Assessing the sources of high fecal coliform levels at an urban tropical beach.

PubMed

Davino, Aline Mendonça Cavalcante; de Melo, Milena Bandeira; Caffaro Filho, Roberto Augusto

2015-01-01

Recreational water quality is commonly assessed by microbial indicators such as fecal coliforms. Maceió is the capital of Alagoas state, located in tropical northeastern Brazil. Its beaches are considered as the most beautiful urban beaches in the country. Jatiúca Beach in Maceió was found to be unsuitable for bathing continuously during the year of 2011. The same level of contamination was not observed in surrounding beaches. The aim of this study was to initiate the search for the sources of these high coliform levels, so that contamination can be eventually mitigated. We performed a retrospective analysis of historical results of fecal coliform concentrations from 2006 to 2012 at five monitoring stations located in the study region. Results showed that Jatiúca Beach consistently presented the worst quality among the studied beaches. A field survey was conducted to identify existing point and non-point sources of pollution in the area. Monitoring in the vicinity of Jatiúca was spatially intensified. Fecal coliform concentrations were categorized according to tide range and tide stage. A storm drain located in northern Jatiúca was identified as the main point source of the contamination. However, fecal coliform concentrations at Jatiúca were high during high tides and spring tides even when this point source was inactive (no rainfall). We hypothesize that high fecal coliform levels in Jatiúca Beach may also be caused by aquifer contamination or, more likely, from tide washing of contaminated sand. Both of these hypotheses will be further investigated.

Using spatial-stream-network models and long-term data to understand and predict dynamics of faecal contamination in a mixed land-use catchment.

PubMed

Neill, Aaron James; Tetzlaff, Doerthe; Strachan, Norval James Colin; Hough, Rupert Lloyd; Avery, Lisa Marie; Watson, Helen; Soulsby, Chris

2018-01-15

An 11year dataset of concentrations of E. coli at 10 spatially-distributed sites in a mixed land-use catchment in NE Scotland (52km 2 ) revealed that concentrations were not clearly associated with flow or season. The lack of a clear flow-concentration relationship may have been due to greater water fluxes from less-contaminated headwaters during high flows diluting downstream concentrations, the importance of persistent point sources of E. coli both anthropogenic and agricultural, and possibly the temporal resolution of the dataset. Point sources and year-round grazing of livestock probably obscured clear seasonality in concentrations. Multiple linear regression models identified potential for contamination by anthropogenic point sources as a significant predictor of long-term spatial patterns of low, average and high concentrations of E. coli. Neither arable nor pasture land was significant, even when accounting for hydrological connectivity with a topographic-index method. However, this may have reflected coarse-scale land-cover data inadequately representing "point sources" of agricultural contamination (e.g. direct defecation of livestock into the stream) and temporal changes in availability of E. coli from diffuse sources. Spatial-stream-network models (SSNMs) were applied in a novel context, and had value in making more robust catchment-scale predictions of concentrations of E. coli with estimates of uncertainty, and in enabling identification of potential "hot spots" of faecal contamination. Successfully managing faecal contamination of surface waters is vital for safeguarding public health. Our finding that concentrations of E. coli could not clearly be associated with flow or season may suggest that management strategies should not necessarily target only high flow events or summer when faecal contamination risk is often assumed to be greatest. Furthermore, we identified SSNMs as valuable tools for identifying possible "hot spots" of contamination which could be targeted for management, and for highlighting areas where additional monitoring could help better constrain predictions relating to faecal contamination. Copyright © 2017 Elsevier B.V. All rights reserved.

Mercury Contaminated Sediment Sites: A Review Of Remedial Solutions

EPA Science Inventory

Mercury (Hg) can accumulate in sediment from point and non-point sources, depending on a number of physical, chemical, biological, geological and anthropogenic environmental processes. It is believed that the associated Hg contamination in aquatic systems can be decreased by imp...

Field-deployed Metabolomics for Assessing Waters Impacted by Point and Non-Point Sources of Contamination

EPA Science Inventory

Metabolomics is becoming well-established for studying chemical contaminant-induced alterations to normal biological function. For example, the literature contains a wealth of laboratory-based studies involving analysis of samples from organisms exposed to individual chemical tox...

Field-deployed Metabolomics for Assessing Surface Waters Impacted by Point and Non-Point Sources of Contamination

EPA Science Inventory

Metabolomics has become well-established for studying chemical contaminant-induced alterations to normal biological function. For example, the literature contains a wealth of laboratory-based studies involving analysis of samples from organisms exposed to individual chemical toxi...

Evaluating impacts of pulp and paper mill process changes on bioactive contaminant loading to St. Louis Bay.

EPA Science Inventory

As a convergence point for human waste streams, wastewater treatment plants are recognized as point sources through which contaminants originating from domestic, industrial, and commercial activities enter surface waters. Effluent from the Western Lake Superior Sanitary District ...

Bacteriological quality of drinking water in Nyala, South Darfur, Sudan.

PubMed

Abdelrahman, Amira Ahmed; Eltahir, Yassir Mohammed

2011-04-01

The objective of this study was to determine the bacterial contaminations in drinking water in Nyala city, South Darfur, Sudan with special reference to the internally displaced people camps (IDPs). Two hundred and forty water samples from different sites and sources including bore holes, hand pumps, dug wells, water points, water reservoir and household storage containers were collected in 2009. The most probable number method was used to detect and count the total coliform, faecal coliform and faecal enterococci. Results revealed that the three indicators bacteria were abundant in all sources except water points. Percentages of the three indicators bacteria count above the permissible limits for drinking water in all samples were 46.4% total coliform, 45.2% faecal coliform and 25.4% faecal enterococci whereas the highest count of the indicators bacteria observed was 1,600 U/100 ml water. Enteric bacteria isolated were Escherichia coli (22.5%), Enterococcus faecalis (20.42%), Klebsiella (15.00%), Citrobacter (2.1%) and Enterobacter (3.33%). The highest contamination of water sources was observed in household storage containers (20%) followed by boreholes (11.25%), reservoirs (6.24%), hand pumps (5.42%) and dug wells (2.49%). Contamination varied from season to season with the highest level in autumn (18.33%) followed by winter (13.75%) and summer (13.32%), respectively. All sources of water in IDP camps except water points were contaminated. Data suggested the importance of greater attention for household contamination, environmental sanitation control and the raise of awareness about water contamination.

Organic contaminant transport and fate in the subsurface: Evolution of knowledge and understanding

NASA Astrophysics Data System (ADS)

Essaid, Hedeff I.; Bekins, Barbara A.; Cozzarelli, Isabelle M.

2015-07-01

Toxic organic contaminants may enter the subsurface as slightly soluble and volatile nonaqueous phase liquids (NAPLs) or as dissolved solutes resulting in contaminant plumes emanating from the source zone. A large body of research published in Water Resources Research has been devoted to characterizing and understanding processes controlling the transport and fate of these organic contaminants and the effectiveness of natural attenuation, bioremediation, and other remedial technologies. These contributions include studies of NAPL flow, entrapment, and interphase mass transfer that have advanced from the analysis of simple systems with uniform properties and equilibrium contaminant phase partitioning to complex systems with pore-scale and macroscale heterogeneity and rate-limited interphase mass transfer. Understanding of the fate of dissolved organic plumes has advanced from when biodegradation was thought to require oxygen to recognition of the importance of anaerobic biodegradation, multiple redox zones, microbial enzyme kinetics, and mixing of organic contaminants and electron acceptors at plume fringes. Challenges remain in understanding the impacts of physical, chemical, biological, and hydrogeological heterogeneity, pore-scale interactions, and mixing on the fate of organic contaminants. Further effort is needed to successfully incorporate these processes into field-scale predictions of transport and fate. Regulations have greatly reduced the frequency of new point-source contamination problems; however, remediation at many legacy plumes remains challenging. A number of fields of current relevance are benefiting from research advances from point-source contaminant research. These include geologic carbon sequestration, nonpoint-source contamination, aquifer storage and recovery, the fate of contaminants from oil and gas development, and enhanced bioremediation.

Organic contaminant transport and fate in the subsurface: evolution of knowledge and understanding

USGS Publications Warehouse

Essaid, Hedeff I.; Bekins, Barbara A.; Cozzarelli, Isabelle M.

2015-01-01

Toxic organic contaminants may enter the subsurface as slightly soluble and volatile nonaqueous phase liquids (NAPLs) or as dissolved solutes resulting in contaminant plumes emanating from the source zone. A large body of research published in Water Resources Research has been devoted to characterizing and understanding processes controlling the transport and fate of these organic contaminants and the effectiveness of natural attenuation, bioremediation, and other remedial technologies. These contributions include studies of NAPL flow, entrapment, and interphase mass transfer that have advanced from the analysis of simple systems with uniform properties and equilibrium contaminant phase partitioning to complex systems with pore-scale and macroscale heterogeneity and rate-limited interphase mass transfer. Understanding of the fate of dissolved organic plumes has advanced from when biodegradation was thought to require oxygen to recognition of the importance of anaerobic biodegradation, multiple redox zones, microbial enzyme kinetics, and mixing of organic contaminants and electron acceptors at plume fringes. Challenges remain in understanding the impacts of physical, chemical, biological, and hydrogeological heterogeneity, pore-scale interactions, and mixing on the fate of organic contaminants. Further effort is needed to successfully incorporate these processes into field-scale predictions of transport and fate. Regulations have greatly reduced the frequency of new point-source contamination problems; however, remediation at many legacy plumes remains challenging. A number of fields of current relevance are benefiting from research advances from point-source contaminant research. These include geologic carbon sequestration, nonpoint-source contamination, aquifer storage and recovery, the fate of contaminants from oil and gas development, and enhanced bioremediation.

Monitoring coastal marine waters for spore-forming bacteria of faecal and soil origin to determine point from non-point source pollution.

PubMed

Fujioka, R S

2001-01-01

The US Environmental Protection Agency (USEPA) and the World Health Organization (WHO) have established recreational water quality standards limiting the concentrations of faecal indicator bacteria (faecal coliform, E. coli, enterococci) to ensure that these waters are safe for swimming. In the application of these hygienic water quality standards, it is assumed that there are no significant environmental sources of these faecal indicator bacteria which are unrelated to direct faecal contamination. However, we previously reported that these faecal indicator bacteria are able to grow in the soil environment of humid tropical island environments such as Hawaii and Guam and are transported at high concentrations into streams and storm drains by rain. Thus, streams and storm drains in Hawaii contain consistently high concentrations of faecal indicator bacteria which routinely exceed the EPA and WHO recreational water quality standards. Since, streams and storm drains eventually flow out to coastal marine waters, we hypothesize that all the coastal beaches which receive run-off from streams and storm drains will contain elevated concentrations of faecal indicator bacteria. To test this hypothesis, we monitored the coastal waters at four beaches known to receive water from stream or storm drains for salinity, turbidity, and used the two faecal indicator bacteria (E. coli, enterococci) to establish recreational water quality standards. To determine if these coastal waters are contaminated with non-point source pollution (streams) or with point source pollution (sewage effluent), these same water samples were also assayed for spore-forming bacteria of faecal origin (Cl. perfringens) and of soil origin (Bacillus species). Using this monitoring strategy it was possible to determine when coastal marine waters were contaminated with non-point source pollution and when coastal waters were contaminated with point source pollution. The results of this study are most likely applicable to all countries in the warm and humid region of the world.

Quality of drinking-water at source and point-of-consumption--drinking cup as a high potential recontamination risk: a field study in Bolivia.

PubMed

Rufener, Simonne; Mäusezahl, Daniel; Mosler, Hans-Joachim; Weingartner, Rolf

2010-02-01

In-house contamination of drinking-water is a persistent problem in developing countries. This study aimed at identifying critical points of contamination and determining the extent of recontamination after water treatment. In total, 81 households were visited, and 347 water samples from their current sources of water, transport vessels, treated water, and drinking vessels were analyzed. The quality of water was assessed using Escherichia coli as an indicator for faecal contamination. The concentration of E. coli increased significantly from the water source [median=0 colony-forming unit (CFU)/100 mL, interquartile range (IQR: 0-13)] to the drinking cup (median=8 CFU/100 mL; IQR: 0-550; n=81, z=-3.7, p<0.001). About two-thirds (34/52) of drinking vessels were contaminated with E. coli. Although boiling and solar disinfection of water (SODIS) improved the quality of drinking-water (median=0 CFU/100 mL; IQR: 0-0.05), recontamination at the point-of-consumption significantly reduced the quality of water in the cups (median=8, IQR: 0-500; n=45, z=-2.4, p=0.015). Home-based interventions in disinfection of water may not guarantee health benefits without complementary hygiene education due to the risk of posttreatment contamination.

Reduction of point contamination sources of pesticide from a vineyard farm.

PubMed

Fait, Gabriella; Nicelli, Marco; Fragoulis, George; Trevisan, Marco; Capri, Ettore

2007-05-01

Although plant protection products are already regulated in Europe under Directive 91/414/EEC, there is increasing concern about the pollution of ground and surface water caused by point sources of pesticides, such as tank filling, spillages, faulty equipment, washing, waste disposal, and direct contamination. One tool for the reduction of pesticide point source contamination is a biological system where chemicals are bound and biologically degraded. This paper presents an offset lined system where wastewaters containing pesticide residues leach through a biomix. A pump system is provided to pump the water onto the surface of the biomix and allow it to drain under gravity, keeping the biomix wet. The analysis of residues of nine pesticides in the water, biomix, and sediment inside the tank showed the biobed to function well, with a water decontamination greater than 90%. The use of this system mitigated the potential for pollution (pesticide concentrations higher than 0.1 microg/L) of 1 km of the river system surrounding the farm.

Water-Related Infrastructure in a Region of Post-Earthquake Haiti: High Levels of Fecal Contamination and Need for Ongoing Monitoring

PubMed Central

Widmer, Jocelyn M.; Weppelmann, Thomas A.; Alam, Meer T.; Morrissey, B. David; Redden, Edsel; Rashid, Mohammed H.; Diamond, Ulrica; Ali, Afsar; De Rochars, Madsen Beau; Blackburn, Jason K.; Johnson, Judith A.; Morris, J. Glenn

2014-01-01

We inventoried non-surface water sources in the Leogane and Gressier region of Haiti (approximately 270 km2) in 2012 and 2013 and screened water from 345 sites for fecal coliforms and Vibrio cholerae. An international organization/non-governmental organization responsible for construction could be identified for only 56% of water points evaluated. Sixteen percent of water points were non-functional at any given time; 37% had evidence of fecal contamination, with spatial clustering of contaminated sites. Among improved water sources (76% of sites), 24.6% had fecal coliforms versus 80.9% in unimproved sources. Fecal contamination levels increased significantly from 36% to 51% immediately after the passage of Tropical Storm Sandy in October of 2012, with a return to 34% contamination in March of 2013. Long-term sustainability of potable water delivery at a regional scale requires ongoing assessment of water quality, functionality, and development of community-based management schemes supported by a national plan for the management of potable water. PMID:25071005

Water-related infrastructure in a region of post-earthquake Haiti: high levels of fecal contamination and need for ongoing monitoring.

PubMed

Widmer, Jocelyn M; Weppelmann, Thomas A; Alam, Meer T; Morrissey, B David; Redden, Edsel; Rashid, Mohammed H; Diamond, Ulrica; Ali, Afsar; De Rochars, Madsen Beau; Blackburn, Jason K; Johnson, Judith A; Morris, J Glenn

2014-10-01

We inventoried non-surface water sources in the Leogane and Gressier region of Haiti (approximately 270 km(2)) in 2012 and 2013 and screened water from 345 sites for fecal coliforms and Vibrio cholerae. An international organization/non-governmental organization responsible for construction could be identified for only 56% of water points evaluated. Sixteen percent of water points were non-functional at any given time; 37% had evidence of fecal contamination, with spatial clustering of contaminated sites. Among improved water sources (76% of sites), 24.6% had fecal coliforms versus 80.9% in unimproved sources. Fecal contamination levels increased significantly from 36% to 51% immediately after the passage of Tropical Storm Sandy in October of 2012, with a return to 34% contamination in March of 2013. Long-term sustainability of potable water delivery at a regional scale requires ongoing assessment of water quality, functionality, and development of community-based management schemes supported by a national plan for the management of potable water. © The American Society of Tropical Medicine and Hygiene.

Pharmaceuticals, hormones, anthropogenic waste indicators, and total estrogenicity in liquid and solid samples from municipal sludge stabilization and dewatering

USGS Publications Warehouse

Furlong, Edward T.; Gray, James L.; Quanrud, David M.; Teske, Sondra S.; Werner, Stephen L.; Esposito, Kathleen; Marine, Jeremy; Ela, Wendell P.; Zaugg, Steven D.; Phillips, Patrick J.; Stinson, Beverley

2012-01-01

The ubiquitous presence of pharmaceuticals and other emerging contaminants, or trace organic compounds, in surface water has resulted in research and monitoring efforts to identify contaminant sources to surface waters and to better understand loadings from these sources. Wastewater treatment plant discharges have been identified as an important point source of trace organic compounds to surface water and understanding the transport and transformation of these contaminants through wastewater treatment process is essential to controlling their introduction to receiving waters.

Assessment of Groundwater Susceptibility to Non-Point Source Contaminants Using Three-Dimensional Transient Indexes.

PubMed

Zhang, Yong; Weissmann, Gary S; Fogg, Graham E; Lu, Bingqing; Sun, HongGuang; Zheng, Chunmiao

2018-06-05

Groundwater susceptibility to non-point source contamination is typically quantified by stable indexes, while groundwater quality evolution (or deterioration globally) can be a long-term process that may last for decades and exhibit strong temporal variations. This study proposes a three-dimensional (3- d ), transient index map built upon physical models to characterize the complete temporal evolution of deep aquifer susceptibility. For illustration purposes, the previous travel time probability density (BTTPD) approach is extended to assess the 3- d deep groundwater susceptibility to non-point source contamination within a sequence stratigraphic framework observed in the Kings River fluvial fan (KRFF) aquifer. The BTTPD, which represents complete age distributions underlying a single groundwater sample in a regional-scale aquifer, is used as a quantitative, transient measure of aquifer susceptibility. The resultant 3- d imaging of susceptibility using the simulated BTTPDs in KRFF reveals the strong influence of regional-scale heterogeneity on susceptibility. The regional-scale incised-valley fill deposits increase the susceptibility of aquifers by enhancing rapid downward solute movement and displaying relatively narrow and young age distributions. In contrast, the regional-scale sequence-boundary paleosols within the open-fan deposits "protect" deep aquifers by slowing downward solute movement and displaying a relatively broad and old age distribution. Further comparison of the simulated susceptibility index maps to known contaminant distributions shows that these maps are generally consistent with the high concentration and quick evolution of 1,2-dibromo-3-chloropropane (DBCP) in groundwater around the incised-valley fill since the 1970s'. This application demonstrates that the BTTPDs can be used as quantitative and transient measures of deep aquifer susceptibility to non-point source contamination.

Probabilistic Analysis of Earthquake-Led Water Contamination: A Case of Sichuan, China

NASA Astrophysics Data System (ADS)

Yang, Yan; Li, Lin; Benjamin Zhan, F.; Zhuang, Yanhua

2016-06-01

The objective of this paper is to evaluate seismic-led point source and non-point source water pollution, under the seismic hazard of 10 % probability of exceedance in 50 years, and with the minimum value of the water quality standard in Sichuan, China. The soil conservation service curve number method of calculating the runoff depth in the single rainfall event combined with the seismic damage index were applied to estimate the potential degree of non-point source water pollution. To estimate the potential impact of point source water pollution, a comprehensive water pollution evaluation framework is constructed using a combination of Water Quality Index and Seismic Damage Index methods. The four key findings of this paper are: (1) The water catchment that has the highest factory concentration does not have the highest risk of non-point source water contamination induced by the outbreak of potential earthquake. (2) The water catchment that has the highest numbers of cumulative water pollutants types are typically located in the south western parts of Sichuan where the main river basins in the regions flow through. (3) The most common pollutants in sample factories studied is COD and NH3-N which are found in all catchments. The least common pollutant is pathogen—found present in W1 catchment which has the best rating in the water quality index. (4) Using water quality index as a standardization parameter, parallel comparisons is made among the 16 water catchments. Only catchment W1 reaches level II water quality status which has the rating of moderately polluted in events of earthquake induced water contamination. All other areas suffer from severe water contamination with multiple pollution sources. The results from the data model are significant to urban planning commissions and businesses to strategically choose their factory locations in order to minimize potential hazardous impact during the outbreak of earthquake.

CARIDEAN GRASS SHRIMP (PALAEMONETES PUGIO HOLTHIUS) AS AN INDICATOR OF SEDIMENT QUALITY IN FLORIDA COASTAL AREAS AFFECTED BY POINT AND NON-POINT SOURCE CONTAMINATION

EPA Science Inventory

Grass shrimp are one of the more widely distributed estuarine benthic organisms along the Gulf of Mexico and Atlantic coasts, but they have been used infrequently in contaminated sediment assessments. Early life stages of the caridean grass shrimp, Palaemonetes pugio (Holthuis), ...

Urban Runoff Impact on the qPCR Signal of Enterococci and Other Alternative Fecal Indicators in a Tropical Beach

EPA Science Inventory

In order to effectively control inputs of contamination to coastal recreational waters, an improved understanding of the impact of both point and non-point sources of urban runoff is needed. In this study, we focused on the effect of non-point source urban runoff on the enterococ...

Measuring Spatial Variability of Vapor Flux to Characterize Vadose-zone VOC Sources: Flow-cell Experiments

DOE PAGES

Mainhagu, Jon; Morrison, C.; Truex, Michael J.; ...

2014-08-05

A method termed vapor-phase tomography has recently been proposed to characterize the distribution of volatile organic contaminant mass in vadose-zone source areas, and to measure associated three-dimensional distributions of local contaminant mass discharge. The method is based on measuring the spatial variability of vapor flux, and thus inherent to its effectiveness is the premise that the magnitudes and temporal variability of vapor concentrations measured at different monitoring points within the interrogated area will be a function of the geospatial positions of the points relative to the source location. A series of flow-cell experiments was conducted to evaluate this premise. Amore » well-defined source zone was created by injection and extraction of a non-reactive gas (SF6). Spatial and temporal concentration distributions obtained from the tests were compared to simulations produced with a mathematical model describing advective and diffusive transport. Tests were conducted to characterize both areal and vertical components of the application. Decreases in concentration over time were observed for monitoring points located on the opposite side of the source zone from the local–extraction point, whereas increases were observed for monitoring points located between the local–extraction point and the source zone. We found that the results illustrate that comparison of temporal concentration profiles obtained at various monitoring points gives a general indication of the source location with respect to the extraction and monitoring points.« less

Drivers of microbiological quality of household drinking water - a case study in rural Ethiopia.

PubMed

Usman, Muhammed A; Gerber, Nicolas; Pangaribowo, Evita H

2018-04-01

This study aims at assessing the determinants of microbiological contamination of household drinking water under multiple-use water systems in rural areas of Ethiopia. For this analysis, a random sample of 454 households was surveyed between February and March 2014, and water samples from community sources and household storage containers were collected and tested for fecal contamination. The number of Escherichia coli (E. coli) colony-forming units per 100 mL water was used as an indicator of fecal contamination. The microbiological tests demonstrated that 58% of household stored water samples and 38% of protected community water sources were contaminated with E. coli. Moreover, most improved water sources often considered to provide safe water showed the presence of E. coli. The result shows that households' stored water collected from unprotected wells/springs had higher levels of E. coli than stored water from alternative sources. Distance to water sources and water collection containers are also strongly associated with stored water quality. To ensure the quality of stored water, the study suggests that there is a need to promote water safety from the point-of-source to point-of-use, with due considerations for the linkages between water and agriculture to advance the Sustainable Development Goal 6 of ensuring access to clean water for everyone.

Distinguishing the Effects of Local Point Sources from Those Caused by Upstream Nonpoint Source (NPS) Inputs: Refinement of a Watershed Development Index for New England

EPA Science Inventory

Using EMAP data from the NE Wadeable Stream Survey and state datasets (CT, ME), assessment tools were developed to predict diffuse NPS effects from watershed development and distinguish these from local impacts (point sources, contaminated sediments). Classification schemes were...

Monitoring Fecal Indicators and Pathogens in Watersheds: Implementing a Quantitative Microbial Risk Assessment Approach

EPA Science Inventory

- Many of the nation's rivers, lakes, and estuaries are impaired with fecal indicator bacteria. - Fecal contamination from point and non-point sources is responsible for the presence of fecal pathogens in source and recreational waters - Effective compliance with TMDL regulatio...

A Comparative Analysis of Vibrio cholerae Contamination in Point-of-Drinking and Source Water in a Low-Income Urban Community, Bangladesh.

PubMed

Ferdous, Jannatul; Sultana, Rebeca; Rashid, Ridwan B; Tasnimuzzaman, Md; Nordland, Andreas; Begum, Anowara; Jensen, Peter K M

2018-01-01

Bangladesh is a cholera endemic country with a population at high risk of cholera. Toxigenic and non-toxigenic Vibrio cholerae ( V. cholerae ) can cause cholera and cholera-like diarrheal illness and outbreaks. Drinking water is one of the primary routes of cholera transmission in Bangladesh. The aim of this study was to conduct a comparative assessment of the presence of V. cholerae between point-of-drinking water and source water, and to investigate the variability of virulence profile using molecular methods of a densely populated low-income settlement of Dhaka, Bangladesh. Water samples were collected and tested for V. cholerae from "point-of-drinking" and "source" in 477 study households in routine visits at 6 week intervals over a period of 14 months. We studied the virulence profiles of V. cholerae positive water samples using 22 different virulence gene markers present in toxigenic O1/O139 and non-O1/O139 V. cholerae using polymerase chain reaction (PCR). A total of 1,463 water samples were collected, with 1,082 samples from point-of-drinking water in 388 households and 381 samples from 66 water sources. V. cholerae was detected in 10% of point-of-drinking water samples and in 9% of source water samples. Twenty-three percent of households and 38% of the sources were positive for V. cholerae in at least one visit. Samples collected from point-of-drinking and linked sources in a 7 day interval showed significantly higher odds ( P < 0.05) of V. cholerae presence in point-of-drinking compared to source [OR = 17.24 (95% CI = 7.14-42.89)] water. Based on the 7 day interval data, 53% (17/32) of source water samples were negative for V. cholerae while linked point-of-drinking water samples were positive. There were significantly higher odds ( p < 0.05) of the presence of V. cholerae O1 [OR = 9.13 (95% CI = 2.85-29.26)] and V. cholerae O139 [OR = 4.73 (95% CI = 1.19-18.79)] in source water samples than in point-of-drinking water samples. Contamination of water at the point-of-drinking is less likely to depend on the contamination at the water source. Hygiene education interventions and programs should focus and emphasize on water at the point-of-drinking, including repeated cleaning of drinking vessels, which is of paramount importance in preventing cholera.

Detection of spatial fluctuations of non-point source fecal pollution in coral reef surrounding waters in southwestern Puerto Rico using PCR-based assays.

PubMed

Bonkosky, M; Hernández-Delgado, E A; Sandoz, B; Robledo, I E; Norat-Ramírez, J; Mattei, H

2009-01-01

Human fecal contamination of coral reefs is a major cause of concern. Conventional methods used to monitor microbial water quality cannot be used to discriminate between different fecal pollution sources. Fecal coliforms, enterococci, and human-specific Bacteroides (HF183, HF134), general Bacteroides-Prevotella (GB32), and Clostridium coccoides group (CP) 16S rDNA PCR assays were used to test for the presence of non-point source fecal contamination across the southwestern Puerto Rico shelf. Inshore waters were highly turbid, consistently receiving fecal pollution from variable sources, and showing the highest frequency of positive molecular marker signals. Signals were also detected at offshore waters in compliance with existing microbiological quality regulations. Phylogenetic analysis showed that most isolates were of human fecal origin. The geographic extent of non-point source fecal pollution was large and impacted extensive coral reef systems. This could have deleterious long-term impacts on public health, local fisheries and in tourism potential if not adequately addressed.

Delineating Contaminants and Transport Pathways Within a Coastal Watershed in Southeast Puerto Rico

USDA-ARS?s Scientific Manuscript database

Coastal water quality decline due to point and non-point source pollution from terrestrial sources is a serious concern throughout the Caribbean basin and worldwide. Toxic and noxious algal blooms, declines in mangrove forests and seagrass meadows, depletion of fishery stocks, coral reef die-off, pu...

A Comparative Analysis of Vibrio cholerae Contamination in Point-of-Drinking and Source Water in a Low-Income Urban Community, Bangladesh

PubMed Central

Ferdous, Jannatul; Sultana, Rebeca; Rashid, Ridwan B.; Tasnimuzzaman, Md.; Nordland, Andreas; Begum, Anowara; Jensen, Peter K. M.

2018-01-01

Bangladesh is a cholera endemic country with a population at high risk of cholera. Toxigenic and non-toxigenic Vibrio cholerae (V. cholerae) can cause cholera and cholera-like diarrheal illness and outbreaks. Drinking water is one of the primary routes of cholera transmission in Bangladesh. The aim of this study was to conduct a comparative assessment of the presence of V. cholerae between point-of-drinking water and source water, and to investigate the variability of virulence profile using molecular methods of a densely populated low-income settlement of Dhaka, Bangladesh. Water samples were collected and tested for V. cholerae from “point-of-drinking” and “source” in 477 study households in routine visits at 6 week intervals over a period of 14 months. We studied the virulence profiles of V. cholerae positive water samples using 22 different virulence gene markers present in toxigenic O1/O139 and non-O1/O139 V. cholerae using polymerase chain reaction (PCR). A total of 1,463 water samples were collected, with 1,082 samples from point-of-drinking water in 388 households and 381 samples from 66 water sources. V. cholerae was detected in 10% of point-of-drinking water samples and in 9% of source water samples. Twenty-three percent of households and 38% of the sources were positive for V. cholerae in at least one visit. Samples collected from point-of-drinking and linked sources in a 7 day interval showed significantly higher odds (P < 0.05) of V. cholerae presence in point-of-drinking compared to source [OR = 17.24 (95% CI = 7.14–42.89)] water. Based on the 7 day interval data, 53% (17/32) of source water samples were negative for V. cholerae while linked point-of-drinking water samples were positive. There were significantly higher odds (p < 0.05) of the presence of V. cholerae O1 [OR = 9.13 (95% CI = 2.85–29.26)] and V. cholerae O139 [OR = 4.73 (95% CI = 1.19–18.79)] in source water samples than in point-of-drinking water samples. Contamination of water at the point-of-drinking is less likely to depend on the contamination at the water source. Hygiene education interventions and programs should focus and emphasize on water at the point-of-drinking, including repeated cleaning of drinking vessels, which is of paramount importance in preventing cholera. PMID:29616005

Assessment of ground-water contamination in the alluvial aquifer near West Point, Kentucky

USGS Publications Warehouse

Lyverse, M.A.; Unthank, M.D.

1988-01-01

Well inventories, water level measurements, groundwater quality samples, surface geophysical techniques (specifically, electromagnetic techniques), and test drilling were used to investigate the extent and sources of groundwater contamination in the alluvial aquifer near West Point, Kentucky. This aquifer serves as the principal source of drinking water for over 50,000 people. Groundwater flow in the alluvial aquifer is generally unconfined and moves in a northerly direction toward the Ohio River. Two large public supply well fields and numerous domestic wells are located in this natural flow path. High concentrations of chloride in groundwater have resulted in the abandonment of several public supply wells in the West Point areas. Chloride concentrations in water samples collected for this study were as high as 11,000 mg/L. Electromagnetic techniques indicated and test drilling later confirmed that the source of chloride in well waters was probably improperly plugged or unplugged, abandoned oil and gas exploration wells. The potential for chloride contamination of wells exists in the study area and is related to proximity to improperly abandoned oil and gas exploration wells and to gradients established by drawdowns associated with pumped wells. Periodic use of surface geophysical methods, in combination with added observation wells , could be used to monitor significant changes in groundwater quality related to chloride contamination. (USGS)

40 CFR 419.34 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

Code of Federal Regulations, 2010 CFR

2010-07-01

... limitations for contaminated runoff. The following effluent limitations constitute the quantity and quality of pollutants or pollutant properties controlled by this paragraph and attributable to contaminated runoff which... point source subject to this subpart. (1) If wastewater consists solely of contaminated runoff and is...

Location identification for indoor instantaneous point contaminant source by probability-based inverse Computational Fluid Dynamics modeling.

PubMed

Liu, X; Zhai, Z

2008-02-01

Indoor pollutions jeopardize human health and welfare and may even cause serious morbidity and mortality under extreme conditions. To effectively control and improve indoor environment quality requires immediate interpretation of pollutant sensor readings and accurate identification of indoor pollution history and source characteristics (e.g. source location and release time). This procedure is complicated by non-uniform and dynamic contaminant indoor dispersion behaviors as well as diverse sensor network distributions. This paper introduces a probability concept based inverse modeling method that is able to identify the source location for an instantaneous point source placed in an enclosed environment with known source release time. The study presents the mathematical models that address three different sensing scenarios: sensors without concentration readings, sensors with spatial concentration readings, and sensors with temporal concentration readings. The paper demonstrates the inverse modeling method and algorithm with two case studies: air pollution in an office space and in an aircraft cabin. The predictions were successfully verified against the forward simulation settings, indicating good capability of the method in finding indoor pollutant sources. The research lays a solid ground for further study of the method for more complicated indoor contamination problems. The method developed can help track indoor contaminant source location with limited sensor outputs. This will ensure an effective and prompt execution of building control strategies and thus achieve a healthy and safe indoor environment. The method can also assist the design of optimal sensor networks.

EPA Office of Water (OW): 2002 SPARROW Total NP (Catchments)

EPA Pesticide Factsheets

SPARROW (SPAtially Referenced Regressions On Watershed attributes) is a watershed modeling tool with output that allows the user to interpret water quality monitoring data at the regional and sub-regional scale. The model relates in-stream water-quality measurements to spatially referenced characteristics of watersheds, including pollutant sources and environmental factors that affect rates of pollutant delivery to streams from the land and aquatic, in-stream processing . The core of the model consists of a nonlinear regression equation describing the non-conservative transport of contaminants from point and non-point (or ??diffuse??) sources on land to rivers and through the stream and river network. SPARROW estimates contaminant concentrations, loads (or ??mass,?? which is the product of concentration and streamflow), and yields in streams (mass of nitrogen and of phosphorus entering a stream per acre of land). It empirically estimates the origin and fate of contaminants in streams and receiving bodies, and quantifies uncertainties in model predictions. The model predictions are illustrated through detailed maps that provide information about contaminant loadings and source contributions at multiple scales for specific stream reaches, basins, or other geographic areas.

Compliance Groundwater Monitoring of Nonpoint Sources - Emerging Approaches

NASA Astrophysics Data System (ADS)

Harter, T.

2008-12-01

Groundwater monitoring networks are typically designed for regulatory compliance of discharges from industrial sites. There, the quality of first encountered (shallow-most) groundwater is of key importance. Network design criteria have been developed for purposes of determining whether an actual or potential, permitted or incidental waste discharge has had or will have a degrading effect on groundwater quality. The fundamental underlying paradigm is that such discharge (if it occurs) will form a distinct contamination plume. Networks that guide (post-contamination) mitigation efforts are designed to capture the shape and dynamics of existing, finite-scale plumes. In general, these networks extend over areas less than one to ten hectare. In recent years, regulatory programs such as the EU Nitrate Directive and the U.S. Clean Water Act have forced regulatory agencies to also control groundwater contamination from non-incidental, recharging, non-point sources, particularly agricultural sources (fertilizer, pesticides, animal waste application, biosolids application). Sources and contamination from these sources can stretch over several tens, hundreds, or even thousands of square kilometers with no distinct plumes. A key question in implementing monitoring programs at the local, regional, and national level is, whether groundwater monitoring can be effectively used as a landowner compliance tool, as is currently done at point-source sites. We compare the efficiency of such traditional site-specific compliance networks in nonpoint source regulation with various designs of regional nonpoint source monitoring networks that could be used for compliance monitoring. We discuss advantages and disadvantages of the site vs. regional monitoring approaches with respect to effectively protecting groundwater resources impacted by nonpoint sources: Site-networks provide a tool to enforce compliance by an individual landowner. But the nonpoint source character of the contamination and its typically large spatial extend requires extensive networks at an individual site to accurately and fairly monitor individual compliance. In contrast, regional networks seemingly fail to hold individual landowners accountable. But regional networks can effectively monitor large-scale impacts and water quality trends; and thus inform regulatory programs that enforce management practices tied to nonpoint source pollution. Regional monitoring networks for compliance purposes can face significant challenges in the implementation due to a regulatory and legal landscape that is exclusively structured to address point sources and individual liability, and due to the non-intensive nature of a regional monitoring program (lack of control of hot spots; lack of accountability of individual landowners).

Study of Heavy Metals in a Wetland Area Adjacent to a Waste Disposal Site Near Resolute Bay, Canadian High Arctic

NASA Astrophysics Data System (ADS)

Lund, K. E.; Young, K. L.

2004-05-01

Heavy metal contamination in High Arctic systems is of growing concern. Studies have been conducted measuring long range and large point source pollutants, but little research has been done on small point sources such as municipal waste disposal sites. Many Arctic communities are coastal, and local people consume marine wildlife in which concentrations of heavy metals can accumulate. Waste disposal sites are often located in very close proximity to the coastline and leaching of these metals could contaminate food sources on a local scale. Cadmium and lead are the metals focussed on by this study, as the Northern Contaminants Program recognizes them as metals of concern. During the summer of 2003 a study was conducted near Resolute, Nunavut, Canada, to determine the extent of cadmium and lead leaching from a local dumpsite to an adjacent wetland. The ultimate fate of these contaminants is approximately 1 km downslope in the ocean. Transects covering an area of 0.3 km2 were established downslope from the point of disposal and water and soil samples were collected and analyzed for cadmium and lead. Only trace amounts of cadmium and lead were found in the water samples. In the soil samples, low uniform concentrations of cadmium were found that were slightly above background levels, except for adjacent to the point of waste input where higher concentrations were found. Lead soil concentrations were higher than cadmium and varied spatially with soil material and moisture. Overall, excessive amounts of cadmium and lead contamination do not appear to be entering the marine ecosystem. However, soil material and moisture should be considered when establishing waste disposal sites in the far north

Estimating the susceptibility of surface water in Texas to nonpoint-source contamination by use of logistic regression modeling

USGS Publications Warehouse

Battaglin, William A.; Ulery, Randy L.; Winterstein, Thomas; Welborn, Toby

2003-01-01

In the State of Texas, surface water (streams, canals, and reservoirs) and ground water are used as sources of public water supply. Surface-water sources of public water supply are susceptible to contamination from point and nonpoint sources. To help protect sources of drinking water and to aid water managers in designing protective yet cost-effective and risk-mitigated monitoring strategies, the Texas Commission on Environmental Quality and the U.S. Geological Survey developed procedures to assess the susceptibility of public water-supply source waters in Texas to the occurrence of 227 contaminants. One component of the assessments is the determination of susceptibility of surface-water sources to nonpoint-source contamination. To accomplish this, water-quality data at 323 monitoring sites were matched with geographic information system-derived watershed- characteristic data for the watersheds upstream from the sites. Logistic regression models then were developed to estimate the probability that a particular contaminant will exceed a threshold concentration specified by the Texas Commission on Environmental Quality. Logistic regression models were developed for 63 of the 227 contaminants. Of the remaining contaminants, 106 were not modeled because monitoring data were available at less than 10 percent of the monitoring sites; 29 were not modeled because there were less than 15 percent detections of the contaminant in the monitoring data; 27 were not modeled because of the lack of any monitoring data; and 2 were not modeled because threshold values were not specified.

NUTRIENT CONTAMINATION AS A RESULT OF POINT SOURCE DISCHARGES: A SURVEY

EPA Science Inventory

Nutrients are common contaminants in Gulf of Mexico estuaries and when present in high concentrations, they can cause excessive algal growths and hypoxic conditions. The magnitude and biological significance of nutrient loading to estuarine waters receiving treated wastewaters is...

An Empirical Study of Contamination in Deep, Rapid, and Wide-field Optical Follow-up of Gravitational Wave Events

NASA Astrophysics Data System (ADS)

Cowperthwaite, P. S.; Berger, E.; Rest, A.; Chornock, R.; Scolnic, D. M.; Williams, P. K. G.; Fong, W.; Drout, M. R.; Foley, R. J.; Margutti, R.; Lunnan, R.; Metzger, B. D.; Quataert, E.

2018-05-01

We present an empirical study of contamination in wide-field optical follow-up searches of gravitational wave sources from Advanced LIGO/Virgo using dedicated observations with the Dark Energy Camera. Our search covered ∼56 deg2, with two visits per night, in the i and z bands, followed by an additional set of griz images three weeks later to serve as reference images for subtraction. We achieve 5σ point-source limiting magnitudes of i ≈ 23.5 and z ≈ 22.4 mag in the coadded single-epoch images. We conduct a search for transient objects that mimic the i ‑ z color behavior of both red (i‑z > 0.5 mag) and blue (i‑z < 0 mag) kilonova emission, finding 11 and 10 contaminants, respectively. Independent of color, we identify 48 transients of interest. Additionally, we leverage the rapid cadence of our observations to search for sources with characteristic timescales of ≈1 day and ≈3 hr, finding no potential contaminants. We assess the efficiency of our search with injected point sources, finding that we are 90% (60%) efficient when searching for red (blue) kilonova-like sources to a limiting magnitude of i ≲ 22.5 mag. Using our efficiencies, we derive sky rates for kilonova contaminants of {{ \\mathcal R }}red} ≈ 0.16 deg‑2 and {{ \\mathcal R }}blue}≈ 0.80 deg‑2. The total contamination rate is {{ \\mathcal R }}all}≈ 1.79 deg‑2. We compare our results to previous optical follow-up efforts and comment on the outlook for gravitational wave follow-up searches as additional detectors (e.g., KAGRA, LIGO India) come online in the next decade.

Organic solutes in ground water at the Idaho National Engineering Laboratory

USGS Publications Warehouse

Leenheer, Jerry A.; Bagby, Jefferson C.

1982-01-01

In August 1980, the U.S. Geological Survey started a reconnaissance survey of organic solutes in drinking water sources, ground-water monitoring wells, perched water table monitoring wells, and in select waste streams at the Idaho National Engineering Laboratory (INEL). The survey was to be a two-phase program. In the first phase, 77 wells and 4 potential point sources were sampled for dissolved organic carbon (DOC). Four wells and several potential point sources of insecticides and herbicides were sampled for insecticides and herbicides. Fourteen wells and four potential organic sources were sampled for volatile and semivolatile organic compounds. The results of the DOC analyses indicate no high level (>20 mg/L DOC) organic contamination of ground water. The only detectable insecticide or herbicide was a DDT concentration of 10 parts per trillion (0.01 microgram per liter) in one observation well. The volatile and semivolatile analyses do not indicate the presence of hazardous organic contaminants in significant amounts (>10 micrograms per liter) in the samples taken. Due to the lack of any significant organic ground-water contamination in this reconnaissance survey, the second phase of the study, which was to follow up the first phase by additional sampling of any contaminated wells, was canceled.

Sources, pathways, and relative risks of contaminants in surface water and groundwater: a perspective prepared for the Walkerton inquiry.

PubMed

Ritter, Len; Solomon, Keith; Sibley, Paul; Hall, Ken; Keen, Patricia; Mattu, Gevan; Linton, Beth

2002-01-11

On a global scale, pathogenic contamination of drinking water poses the most significant health risk to humans, and there have been countless numbers of disease outbreaks and poisonings throughout history resulting from exposure to untreated or poorly treated drinking water. However, significant risks to human health may also result from exposure to nonpathogenic, toxic contaminants that are often globally ubiquitous in waters from which drinking water is derived. With this latter point in mind, the objective of this commission paper is to discuss the primary sources of toxic contaminants in surface waters and groundwater, the pathways through which they move in aquatic environments, factors that affect their concentration and structure along the many transport flow paths, and the relative risks that these contaminants pose to human and environmental health. In assessing the relative risk of toxic contaminants in drinking water to humans, we have organized our discussion to follow the classical risk assessment paradigm, with emphasis placed on risk characterization. In doing so, we have focused predominantly on toxic contaminants that have had a demonstrated or potential effect on human health via exposure through drinking water. In the risk assessment process, understanding the sources and pathways for contaminants in the environment is a crucial step in addressing (and reducing) uncertainty associated with estimating the likelihood of exposure to contaminants in drinking water. More importantly, understanding the sources and pathways of contaminants strengthens our ability to quantify effects through accurate measurement and testing, or to predict the likelihood of effects based on empirical models. Understanding the sources, fate, and concentrations of chemicals in water, in conjunction with assessment of effects, not only forms the basis of risk characterization, but also provides critical information required to render decisions regarding regulatory initiatives, remediation, monitoring, and management. Our discussion is divided into two primary themes. First we discuss the major sources of contaminants from anthropogenic activities to aquatic surface and groundwater and the pathways along which these contaminants move to become incorporated into drinking water supplies. Second, we assess the health significance of the contaminants reported and identify uncertainties associated with exposures and potential effects. Loading of contaminants to surface waters, groundwater, sediments, and drinking water occurs via two primary routes: (1) point-source pollution and (2) non-point-source pollution. Point-source pollution originates from discrete sources whose inputs into aquatic systems can often be defined in a spatially explicit manner. Examples of point-source pollution include industrial effluents (pulp and paper mills, steel plants, food processing plants), municipal sewage treatment plants and combined sewage-storm-water overflows, resource extraction (mining), and land disposal sites (landfill sites, industrial impoundments). Non-point-source pollution, in contrast, originates from poorly defined, diffuse sources that typically occur over broad geographical scales. Examples of non-point-source pollution include agricultural runoff (pesticides, pathogens, and fertilizers), storm-water and urban runoff, and atmospheric deposition (wet and dry deposition of persistent organic pollutants such as polychlorinated biphenyls [PCBs] and mercury). Within each source, we identify the most important contaminants that have either been demonstrated to pose significant risks to human health and/or aquatic ecosystem integrity, or which are suspected of posing such risks. Examples include nutrients, metals, pesticides, persistent organic pollutants (POPs), chlorination by-products, and pharmaceuticals. Due to the significant number of toxic contaminants in the environment, we have necessarily restricted our discussion to those chemicals that pose risks to human health via exposure through drinking water. A comprehensive and judicious consideration of the full range of contaminants that occur in surface waters, sediments, and drinking water would be a large undertaking and clearly beyond the scope of this article. However, where available, we have provided references to relevant literature to assist the reader in undertaking a detailed investigation of their own. The information collected on specific chemicals within major contaminant classes was used to determine their relative risk using the hazard quotient (HQ) approach. Hazard quotients are the most widely used method of assessing risk in which the exposure concentration of a stressor, either measured or estimated, is compared to an effect concentration (e.g., no-observed-effect concentration or NOEC). A key goal of this assessment was to develop a perspective on the relative risks associated with toxic contaminants that occur in drinking water. Data used in this assessment were collected from literature sources and from the Drinking Water Surveillance Program (DWSP) of Ontario. For many common contaminants, there was insufficient environmental exposure (concentration) information in Ontario drinking water and groundwater. Hence, our assessment was limited to specific compounds within major contaminant classes including metals, disinfection by-products, pesticides, and nitrates. For each contaminant, the HQ was estimated by expressing the maximum concentration recorded in drinking water as a function of the water quality guideline for that compound. There are limitations to using the hazard quotient approach of risk characterization. For example, HQs frequently make use of worst-case data and are thus designed to be protective of almost all possible situations that may occur. However, reduction of the probability of a type II error (false negative) through the use of very conservative application factors and assumptions can lead to the implementation of expensive measures of mitigation for stressors that may pose little threat to humans or the environment. It is important to realize that our goal was not to conduct a comprehensive, in-depth assessment of risk for each chemical; more comprehensive assessments of managing risks associated with drinking water are addressed in a separate issue paper by Krewski et al. (2001a). Rather, our goal was to provide the reader with an indication of the relative risk of major contaminant classes as a basis for understanding the risks associated with the myriad forms of toxic pollutants in aquatic systems and drinking water. For most compounds, the estimated HQs were < 1. This indicates that there is little risk associated with exposure from drinking water to the compounds tested. There were some exceptions. For example, nitrates were found to commonly yield HQ values well above 1 in- many rural areas. Further, lead, total trihalomethanes, and trichloroacetic acid yielded HQs > 1 in some treated distribution waters (water distributed to households). These latter compounds were further assessed using a probabilistic approach; these assessments indicated that the maximum allowable concentrations (MAC) or interim MACs for the respective compounds were exceeded <5% of the time. In other words, the probability of finding these compounds in drinking water at levels that pose risk to humans through ingestion of drinking water is low. Our review has been carried out in accordance with the conventional principles of risk assessment. Application of the risk assessment paradigm requires rigorous data on both exposure and toxicity in order to adequately characterize potential risks of contaminants to human health and ecological integrity. Weakness rendered by poor data, or lack of data, in either the exposure or effects stages of the risk assessment process significantly reduces the confidence that can be placed in the overall risk assessment. (ABSTRACT TRUNCATED)

Status of metal levels and their potential sources of contamination in Southeast Asian rivers.

PubMed

Chanpiwat, Penradee; Sthiannopkao, Suthipong

2014-01-01

To assess the concentration and status of metal contaminants in four major Southeast Asian river systems, water were collected from the Tonle Sap-Bassac Rivers (Cambodia), Citarum River (Indonesia), lower Chao Phraya River (Thailand), and Saigon River (Vietnam) in both dry and wet seasons. The target elements were Be, Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Mo, Ag, Cd, Ba, Tl, and Pb and the concentrations exceeded the background metal concentrations by 1- to 88-fold. This distinctly indicates enrichment by human urban area activities. The results of a normalization technique used to distinguish natural from enriched metal concentrations confirmed contamination by Al, Cd, Co, Mn, Ni, Pb, and Zn. Cluster analysis revealed the probable source of metals contamination in most sampling sites on all rivers studied to be anthropogenic, including industrial, commercial, and residential activities. Stable lead isotopes analyses applied to track the sources and pathways of anthropogenic lead furthermore confirmed that anthropogenic sources of metal contaminated these rivers. Discharges of wastewater from both industrial and household activities were major contributors of Pb into the rivers. Non-point sources, especially road runoff and street dust, also contributed contamination from Pb and other metals.

Current aspects of Salmonella contamination in the US poultry production chain and the potential application of risk strategies in understanding emerging hazards.

PubMed

Rajan, Kalavathy; Shi, Zhaohao; Ricke, Steven C

2017-05-01

One of the leading causes of foodborne illness in poultry products is Salmonella enterica. Salmonella hazards in poultry may be estimated and possible control methods modeled and evaluated through the use of quantitative microbiological risk assessment (QMRA) models and tools. From farm to table, there are many possible routes of Salmonella dissemination and contamination in poultry. From the time chicks are hatched through growth, transportation, processing, storage, preparation, and finally consumption, the product could be contaminated through exposure to different materials and sources. Examination of each step of the process is necessary as well as an examination of the overall picture to create effective countermeasures against contamination and prevent disease. QMRA simulation models can use either point estimates or probability distributions to examine variables such as Salmonella concentrations at retail or at any given point of processing to gain insight on the chance of illness due to Salmonella ingestion. For modeling Salmonella risk in poultry, it is important to look at variables such as Salmonella transfer and cross contamination during processing. QMRA results may be useful for the identification and control of critical sources of Salmonella contamination.

Water quality at points-of-use in the Galapagos Islands.

PubMed

Gerhard, William A; Choi, Wan Suk; Houck, Kelly M; Stewart, Jill R

2017-04-01

Piped drinking water is often considered a gold standard for protecting public health but research is needed to explicitly evaluate the effect of centralized treatment systems on water quality in developing world settings. This study examined the effect of a new drinking water treatment plant (DWTP) on microbial drinking water quality at the point-of-use on San Cristobal Island, Galapagos using fecal indicator bacteria total coliforms and Escherichia coli. Samples were collected during six collection periods before and after operation of the DWTP began from the freshwater sources (n=4), the finished water (n=6), and 50 sites throughout the distribution system (n=287). This study found that there was a significant decrease in contamination by total coliforms (two orders of magnitude) and E. coli (one order of magnitude) after DWTP operation began (p<0.001). However, during at least one post-construction collection cycle, total coliforms and E. coli were still found at 66% and 28% of points-of-use (n=50), respectively. During the final collection period, conventional methods were augmented with human-specific Bacteroides assays - validated herein - with the goal of elucidating possible microbial contamination sources. Results show that E. coli contamination was not predictive of contamination by human wastes and suggests that observed indicator bacteria contamination may have environmental origins. Together these findings highlight the necessity of a holistic approach to drinking water infrastructure improvements in order to deliver high quality water through to the point-of-use. Copyright © 2017 Elsevier GmbH. All rights reserved.

Community-based research as a mechanism to reduce environmental health disparities in American Indian and Alaska Native communities

EPA Science Inventory

Racial and ethnic minority communities, including American Indian and Alaska Natives, have been disproportionately impacted by environmental pollution and contamination. This includes siting and location of point sources of pollution, legacies of contamination of drinking and re...

Application of a water quality model in the White Cart water catchment, Glasgow, UK.

PubMed

Liu, S; Tucker, P; Mansell, M; Hursthouse, A

2003-03-01

Water quality models of urban systems have previously focused on point source (sewerage system) inputs. Little attention has been given to diffuse inputs and research into diffuse pollution has been largely confined to agriculture sources. This paper reports on new research that is aimed at integrating diffuse inputs into an urban water quality model. An integrated model is introduced that is made up of four modules: hydrology, contaminant point sources, nutrient cycling and leaching. The hydrology module, T&T consists of a TOPMODEL (a TOPography-based hydrological MODEL), which simulates runoff from pervious areas and a two-tank model, which simulates runoff from impervious urban areas. Linked into the two-tank model, the contaminant point source module simulates the overflow from the sewerage system in heavy rain. The widely known SOILN (SOIL Nitrate model) is the basis of nitrogen cycle module. Finally, the leaching module consists of two functions: the production function and the transfer function. The production function is based on SLIM (Solute Leaching Intermediate Model) while the transfer function is based on the 'flushing hypothesis' which postulates a relationship between contaminant concentrations in the receiving water course and the extent to which the catchment is saturated. This paper outlines the modelling methodology and the model structures that have been developed. An application of this model in the White Cart catchment (Glasgow) is also included.

HISTOPATHOLOGIC BIOMARKERS IN FERAL FRESHWATER FISH POPULATIONS EXPOSED TO DIFFERENT TYPES OF CONTAMINANT STRESS. (R825433)

EPA Science Inventory

Histopathologic alterations of gill, liver, and spleen were studied in feral fish from three freshwater ecosystems that experience different types of contaminant stress. East Fork Poplar Creek (EFPC), a third-order stream in East Tennessee, receives point source discharges of ...

EFFECTS OF WHOLE SEDIMENTS FROM CORPUS CHRISTI BAY ON SURVIVAL, GROWTH AND REPRODUCTION OF THE MYSID, MYSIDOPSIS BAHIA

EPA Science Inventory

Estuarine and marine coastlines are receiving waters for many anthropogenic substances. Concentrations of many of these contaminants have been diminished by regulatory control of effluents, but there is concern that continuing inputs (non-point sources) and contaminants contained...

Monitoring for Pesticides in Groundwater and Surface Water in Nevada, 2008

USGS Publications Warehouse

Thodal, Carl E.; Carpenter, Jon; Moses, Charles W.

2009-01-01

Commercial pesticide applicators, farmers, and homeowners apply about 1 billion pounds of pesticides annually to agricultural land, non-crop land, and urban areas throughout the United States (Gilliom and others, 2006, p. 1). The U.S. Environmental Protection Agency (USEPA) defines a pesticide as any substance used to kill or control insects, weeds, plant diseases, and other pest organisms. Although there are important benefits from the proper use of pesticides, like crop protection and prevention of human disease outbreaks, there are also risks. One risk is the contamination of groundwater and surface-water resources. Data collected during 1992-2001 from 51 major hydrologic systems across the United States indicate that one or more pesticide or pesticide breakdown product was detected in more than 50 percent of 5,057 shallow (less than 20 feet below land surface) wells and in all of the 186 stream sites that were sampled in agricultural and urban areas (Gilliom and others, 2006, p. 2-4). Pesticides can contaminate surface water and groundwater from both point sources and non-point sources. Point sources are from specific locations such as spill sites, disposal sites, pesticide drift during application, and application of pesticides to control aquatic pests. Non-point sources represent the dominant source of surface water and groundwater contamination and may include agricultural and urban runoff, erosion, leaching from application sites, and precipitation that has become contaminated by upwind applications. Pesticides typically enter surface water when rainfall or irrigation exceeds the infiltration capacity of soil and resulting runoff then transports pesticides to streams, rivers, and other surface-water bodies. Contamination of groundwater may result directly from spills near poorly sealed well heads and from pesticide applications through improperly designed or malfunctioning irrigation systems that also are used to apply pesticides (chemigation; Carpenter and Johnson, 1997). Groundwater contamination also may come indirectly by the percolation of agricultural and urban irrigation water through soil layers and into groundwater and from pesticide residue in surface water, such as drainage ditches, streams, and municipal wastewater. To protect surface water and groundwater from pesticide contamination, the USEPA requires that all states establish a pesticide management plan. The Nevada Department of Agriculture (NDOA), with assistance from the USEPA, developed a management program of education (Hefner and Donaldson, 2006), regulation (Johnson and others, 2006), and monitoring (Pennington and others, 2001) to protect Nevada's water resources from pesticide contaminants. Sampling sites are located in areas where urban or agricultural pesticide use may affect groundwater, water bodies, endangered species, and other aquatic life. Information gathered from these sites is used by NDOA to help make regulatory decisions that will protect human and environmental health by reducing and eliminating the occurrence of pesticide contamination. This fact sheet describes current (2008) pesticide monitoring of groundwater and streams by the NDOA in Nevada and supersedes Pennington and others (2001).

Microbial source tracking: a tool for identifying sources of microbial contamination in the food chain.

PubMed

Fu, Ling-Lin; Li, Jian-Rong

2014-01-01

The ability to trace fecal indicators and food-borne pathogens to the point of origin has major ramifications for food industry, food regulatory agencies, and public health. Such information would enable food producers and processors to better understand sources of contamination and thereby take corrective actions to prevent transmission. Microbial source tracking (MST), which currently is largely focused on determining sources of fecal contamination in waterways, is also providing the scientific community tools for tracking both fecal bacteria and food-borne pathogens contamination in the food chain. Approaches to MST are commonly classified as library-dependent methods (LDMs) or library-independent methods (LIMs). These tools will have widespread applications, including the use for regulatory compliance, pollution remediation, and risk assessment. These tools will reduce the incidence of illness associated with food and water. Our aim in this review is to highlight the use of molecular MST methods in application to understanding the source and transmission of food-borne pathogens. Moreover, the future directions of MST research are also discussed.

Microbial Groundwater Quality Status of Hand-Dug Wells and Boreholes in the Dodowa Area of Ghana

PubMed Central

Lutterodt, George; Hoiting, Yvonne; Kamara, Alimamy K.; Oduro-Kwarteng, Sampson; Foppen, Jan Willem A.

2018-01-01

To assess the suitability of water sources for drinking purposes, samples were taken from groundwater sources (boreholes and hand-dug wells) used for drinking water in the Dodowa area of Ghana. The samples were analyzed for the presence of fecal indicator bacteria (Escherichia coli) and viruses (Adenovirus and Rotavirus), using membrane filtration with plating and glass wool filtration with quantitative polymerase chain reaction (PCR), respectively. In addition, sanitary inspection of surroundings of the sources was conducted to identify their vulnerability to pollution. The presence of viruses was also assessed in water samples from the Dodowa River. More than 70% of the hand-dug wells were sited within 10 m of nearby sources of contamination. All sources contained E. coli bacteria, and their numbers in samples of water between dug wells and boreholes showed no significant difference (p = 0.48). Quantitative PCR results for Adenovirus indicated 27% and 55% were positive for the boreholes and hand-dug wells, respectively. Samples from all boreholes tested negative for the presence of Rotavirus while 27% of the dug wells were positive for Rotavirus. PCR tests of 20% of groundwater samples were inhibited. Based on these results we concluded that there is systemic microbial and fecal contamination of groundwater in the area. On-site sanitation facilities, e.g., pit latrines and unlined wastewater drains, are likely the most common sources of fecal contamination of groundwater in the area. Water abstracted from groundwater sources needs to be treated before use for consumption purposes. In addition, efforts should be made to delineate protected areas around groundwater abstraction points to minimize contamination from point sources of pollution. PMID:29649111

Estimation of contamination sources of human enteroviruses in a wastewater treatment and reclamation system by PCR-DGGE.

PubMed

Ji, Zheng; Wang, Xiaochang C; Xu, Limei; Zhang, Chongmiao; Funamizu, Naoyuki; Okabe, Satoshi; Sano, Daisuke

2014-06-01

A polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) method was employed to estimate the contamination sources of human enteroviruses and understand how their dominant strains vary in a wastewater treatment and reclamation system consisting of sewage collection, wastewater treatment with membrane bioreactor and open lakes for reclaimed water storage and reuse. After PCR-DGGE using a selected primer set targeting enteroviruses, phylogenetic analysis of acquired enterovirus gene sequences was performed. Enteroviruses identified from the septic tank were much more diverse than those from grey water and kitchen wastewater. Several unique types of enterovirus different from those in wastewater samples were dominant in a biological wastewater treatment unit. Membrane filtration followed by chlorination was proved effective for physically eliminating enteroviruses; however, secondary contamination likely occurred as the reclaimed water was stored in artificial lakes. Enterovirus 71 (EV71), a hand-foot-and-mouth disease (HFMD) viral pathogen, was detected mainly from the artificial lakes, implying that wastewater effluent was not the contamination source of EV71 and that there were unidentified non-point sources of the contamination with the HFMD viral pathogen in the reclaimed water stored in the artificial lakes. The PCR-DGGE targeting enteroviruses provided robust evidence about viral contamination sources in the wastewater treatment and reclamation system.

USGS Toxic Substances Hydrology Program, 2010

USGS Publications Warehouse

Buxton, Herbert T.

2010-01-01

The U.S. Geological Survey (USGS) Toxic Substances Hydrology Program adapts research priorities to address the most important contamination issues facing the Nation and to identify new threats to environmental health. The Program investigates two major types of contamination problems: * Subsurface Point-Source Contamination, and * Watershed and Regional Contamination. Research objectives include developing remediation methods that use natural processes, characterizing and remediating contaminant plumes in fractured-rock aquifers, identifying new environmental contaminants, characterizing new and understudied pesticides in common pesticide-use settings, explaining mercury methylation and bioaccumulation, and developing approaches for remediating watersheds affected by active and historic mining.

Association of Supply Type with Fecal Contamination of Source Water and Household Stored Drinking Water in Developing Countries: A Bivariate Meta-analysis.

PubMed

Shields, Katherine F; Bain, Robert E S; Cronk, Ryan; Wright, Jim A; Bartram, Jamie

2015-12-01

Access to safe drinking water is essential for health. Monitoring access to drinking water focuses on water supply type at the source, but there is limited evidence on whether quality differences at the source persist in water stored in the household. We assessed the extent of fecal contamination at the source and in household stored water (HSW) and explored the relationship between contamination at each sampling point and water supply type. We performed a bivariate random-effects meta-analysis of 45 studies, identified through a systematic review, that reported either the proportion of samples free of fecal indicator bacteria and/or individual sample bacteria counts for source and HSW, disaggregated by supply type. Water quality deteriorated substantially between source and stored water. The mean percentage of contaminated samples (noncompliance) at the source was 46% (95% CI: 33, 60%), whereas mean noncompliance in HSW was 75% (95% CI: 64, 84%). Water supply type was significantly associated with noncompliance at the source (p < 0.001) and in HSW (p = 0.03). Source water (OR = 0.2; 95% CI: 0.1, 0.5) and HSW (OR = 0.3; 95% CI: 0.2, 0.8) from piped supplies had significantly lower odds of contamination compared with non-piped water, potentially due to residual chlorine. Piped water is less likely to be contaminated compared with other water supply types at both the source and in HSW. A focus on upgrading water services to piped supplies may help improve safety, including for those drinking stored water.

Evaluating Crustal Contamination Effects On The Lithophile Trace Element Budget Of Shergottites, NWA 856 As A Test Case

NASA Technical Reports Server (NTRS)

Brandon, A. D.; Ferdous, J.; Peslier, A. H.

2017-01-01

The issue of whether crustal contamination has affected the lithophile trace element budget of shergottites has been a point of contention for decades. The evaluation has focused on the enriched shergottite compositions as an outcome of crustal contamination of mantle-derived parent magmas or, alternatively, the compositions of these stones reflect an incompatible trace element (ITE) enriched mantle source.

Spatial and temporal variability of contaminants within estuarine sediments and native Olympia oysters: A contrast between a developed and an undeveloped estuary

USGS Publications Warehouse

Granek, Elise F.; Conn, Kathleen E.; Nilsen, Elena B.; Pillsbury, Lori; Strecker, Angela L.; Rumrill, Steve; Fish, William

2016-01-01

Chemical contaminants can be introduced into estuarine and marine ecosystems from a variety of sources including wastewater, agriculture and forestry practices, point and non-point discharges, runoff from industrial, municipal, and urban lands, accidental spills, and atmospheric deposition. The diversity of potential sources contributes to the likelihood of contaminated marine waters and sediments and increases the probability of uptake by marine organisms. Despite widespread recognition of direct and indirect pathways for contaminant deposition and organismal exposure in coastal systems, spatial and temporal variability in contaminant composition, deposition, and uptake patterns are still poorly known. We investigated these patterns for a suite of persistent legacy contaminants including polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) and chemicals of emerging concern including pharmaceuticals within two Oregon coastal estuaries (Coos and Netarts Bays). In the more urbanized Coos Bay, native Olympia oyster (Ostrea lurida) tissue had approximately twice the number of PCB congeners at over seven times the total concentration, yet fewer PBDEs at one-tenth the concentration as compared to the more rural Netarts Bay. Different pharmaceutical suites were detected during each sampling season. Variability in contaminant types and concentrations across seasons and between species and media (organisms versus sediment) indicates the limitation of using indicator species and/or sampling annually to determine contaminant loads at a site or for specific species. The results indicate the prevalence of legacy contaminants and CECs in relatively undeveloped coastal environments highlighting the need to improve policy and management actions to reduce contaminant releases into estuarine and marine waters and to deal with legacy compounds that remain long after prohibition of use. Our results point to the need for better understanding of the ecological and human health risks of exposure to the diverse cocktail of pollutants and harmful compounds that will continue to leach from estuarine sediments over time.

Fecal Pollution of Water

EPA Science Inventory

Fecal pollution of water from a health point of view is the contamination of water with disease-causing organisms (pathogens) that may inhabit the gastrointestinal tract of mammals, but with particular attention to human fecal sources as the most relevant source of human illnesse...

Fecal Pollution of Water.

EPA Science Inventory

Fecal pollution of water from a health point of view is the contamination of water with disease-causing organisms (pathogens) that may inhabit the gastrointestinal tract of mammals, but with particular attention to human fecal sources as the most relevant source of human illnesse...

MICROBIAL SOURCE TRACKING GUIDE DOCUMENT

EPA Science Inventory

Approximately 13% of surface waters in the United States do not meet designated use criteria as determined by high densities of fecal indicator bacteria. Although some of the contamination is attributed to point sources such as confined animal feeding operation (CAFO) and wastew...

An alternative screening model for the estimation of outdoor air concentration at large contaminated sites

NASA Astrophysics Data System (ADS)

Verginelli, Iason; Nocentini, Massimo; Baciocchi, Renato

2017-09-01

Simplified analytical solutions of fate and transport models are often used to carry out risk assessment on contaminated sites, to evaluate the long-term air quality in relation to volatile organic compounds in either soil or groundwater. Among the different assumptions employed to develop these solutions, in this work we focus on those used in the ASTM-RBCA ;box model; for the evaluation of contaminant dispersion in the atmosphere. In this simple model, it is assumed that the contaminant volatilized from the subsurface is dispersed in the atmosphere within a mixing height equal to two meters, i.e. the height of the breathing zone. In certain cases, this simplification could lead to an overestimation of the outdoor air concentration at the point of exposure. In this paper we first discuss the maximum source lengths (in the wind direction) for which the application of the ;box model; can be considered acceptable. Specifically, by comparing the results of ;box model; with the SCREEN3 model of U.S.EPA we found that under very stable atmospheric conditions (class F) the ASTM-RBCA approach provides acceptable results for source lengths up to 200 m while for very unstable atmospheric conditions (class A and B) the overestimation of the concentrations at the point of the exposure can be already observed for source lengths of only 10 m. In the latter case, the overestimation of the ;box model; can be of more than one order of magnitude for source lengths above 500 m. To overcome this limitation, in this paper we introduce a simple analytical solution that can be used for the calculation of the concentration at the point of exposure for large contaminated sites. The method consists in the introduction of an equivalent mixing zone height that allows to account for the dispersion of the contaminants along the source length while keeping the simplistic ;box model; approach that is implemented in most of risk assessment tools that are based on the ASTM-RBCA standard (e.g. RBCA toolkit). Based on our testing, we found that the developed model replicates very well the results of the more sophisticated dispersion SCREEN3 model with deviations always below 10%. The key advantage of this approach is that it can be very easily incorporated in the current risk assessment screening tools that are based on the ASTM standards while ensuring a more accurate evaluation of the concentration at the point of exposure.

Skin dose from radionuclide contamination on clothing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taylor, D.C.; Hussein, E.M.A.; Yuen, P.S.

1997-06-01

Skin dose due to radio nuclide contamination on clothing is calculated by Monte Carlo simulation of electron and photon radiation transport. Contamination due to a hot particle on some selected clothing geometries of cotton garment is simulated. The effect of backscattering in the surrounding air is taken into account. For each combination of source-clothing geometry, the dose distribution function in the skin, including the dose at tissue depths of 7 mg cm{sup -2} and 1,000 Mg cm{sup -2}, is calculated by simulating monoenergetic photon and electron sources. Skin dose due to contamination by a radionuclide is then determined by propermore » weighting of & monoenergetic dose distribution functions. The results are compared with the VARSKIN point-kernel code for some radionuclides, indicating that the latter code tends to under-estimate the dose for gamma and high energy beta sources while it overestimates skin dose for low energy beta sources. 13 refs., 4 figs., 2 tabs.« less

Sources of organochlorine contaminants and mercury in seabirds from the Aleutian archipelago of Alaska: Inferences from spatial and trophic variation

USGS Publications Warehouse

Ricca, Mark A.; Miles, A. Keith; Anthony, Robert G.

2008-01-01

Persistent organochlorine compounds and mercury (Hg) have been detected in numerous coastal organisms of the Aleutian archipelago of Alaska, yet sources of these contaminants are unclear. We collected glaucous-winged gulls, northern fulmars, and tufted puffins along a natural longitudinal gradient across the western and central Aleutian Islands (Buldir, Kiska, Amchitka, Adak), and an additional 8 seabird species representing different foraging and migratory guilds from Buldir Island to evaluate: 1) point source input from former military installations, 2) westward increases in contaminant concentrations suggestive of distant source input, and 3) effects of trophic status (δ15N) and carbon source (δ13C) on contaminant accumulation. Concentrations of Σ polychlorinated biphenyls (PCBs) and most chlorinated pesticides in glaucous-winged gulls consistently exhibited a ‘U’-shaped pattern of high levels at Buldir and the east side of Adak and low levels at Kiska and Amchitka. In contrast, concentrations of Σ PCBs and chlorinated pesticides in northern fulmars and tufted puffins did not differ among islands. Hg concentrations increased westward in glaucous-winged gulls and were highest in northern fulmars from Buldir. Among species collected only at Buldir, Hg was notably elevated in pelagic cormorants, and relatively high Σ PCBs were detected in black-legged kittiwakes. Concentrations of Σ PCBs, dichlorodiphenyldichloroethylene (p,p′ DDE), and Hg were positively correlated with δ15N across all seabird species, indicating biomagnification across trophic levels. The east side of Adak Island (a former military installation) was a likely point source of Σ PCBs and p,p′ DDE, particularly in glaucous-winged gulls. In contrast, elevated levels of these contaminants and Hg, along with PCB congener and chlorinated pesticide compositional patterns detected at Buldir Island indicated exposure from distant sources influenced by a combination of atmospheric–oceanic processes and the migratory movements of seabirds.

Activity ratios in soil contaminated by the source of different reactor condition in the FDNPP accident

NASA Astrophysics Data System (ADS)

Satou, Yukihiko; Sueki, Keisuke; Sasa, Kimikazu; Matsunaka, Tetsuya; Shibayama, Nao; Takahashi, Tsutomu; Kinoshita, Norikazu

2014-05-01

The Fukushima Dai-ichi Nuclear power plant (FDNPP) accident caused radioactive contamination on the surface soil at Fukushima and its adjacent prefectures. Substantial contamination has been found in the northwestern area from the FDNPP, according to the airborne monitoring and ground base survey by the Japanese government. Activity ratios would have characteristic information on emission sources because each relevant reactor had different amount of radionuclide and different activity ratio. The ratios can be used to clarify more detailed source and process in the contamination. We have addressed to consider them in Namie town, northwestern region from the FDNPP. This study focused on the gamma-ray emitting radionuclides of 134Cs, 137Cs, and 110mAg. The activities were decay-corrected as of 11th March, 2011 when all nuclear reactors scrammed. Data of activity ratios by our results and the Japanese official report classified the investigated northwestern region into 3 groups. Ratios of 0.02 for 110mAg/137Cs and 0.90 for 134Cs/137Cs were observed in the northern region of 15 km inside from the FDNPP. On the other hand, two kinds of 110mAg/137Cs ratios of 0.005 and 0.002 were distributed broadly in the region 60 km away from the plant. The 134Cs/137Cs ratio was 0.98 there. The activity ratios of 110mAg/137Cs and 134Cs/137Cs in the northern region from the FDNPP correspond to those of nuclear fuel in Unit 1 according to estimation using the ORIGEN code. The 134Cs/137Cs in the northwestern area from FDNPP agrees with that of Unit 2 and 3. The 110mAg/137Cs ratios of 0.005 and0.002 are 1/5 - 1/10 of the Unit 2 and 3. Official report has announced that discharges of the radionuclides from Unit 2 and 3 occurred on 14th March, 2011. It is known that contamination in the northwestern region from the FDNPP took place on 15th March, 2011. Plausible species for silver in reactor core, metal, and halide etc. have higher boiling point than those species for cesium. The core would be cooled down to lower temperature of the boiling point of silver at the timing contamination occurred. Thus, silver with higher boiling point was not much released than cesium with lower boiling point. The 110mAg/137Cs ratio has served to identify the specific sources of contamination in the northwestern area from the FDNPP.

The distribution of infrared point sources in nearby elliptical galaxies

NASA Astrophysics Data System (ADS)

Gogoi, Rupjyoti; Shalima, P.; Misra, Ranjeev

2018-02-01

Infrared (IR) point sources as observed by Spitzer, in nearby early-type galaxies should either be bright sources in the galaxy such as globular clusters, or they may be background sources such as AGNs. These objects are often counterparts of sources in other wavebands such as optical and X-rays and the IR information provides crucial information regarding their nature. However, many of the IR sources may be background objects and it is important to identify them or at least quantify the level of background contamination. Moreover, the distribution of these IR point sources in flux, distance from the centre and colour would be useful in understanding their origin. Archival Spitzer IRAC images provide a unique opportunity for such a study and here we present the results of such an analysis for four nearby galaxies, NGC 1399, NGC 2768, NGC 4365 and NGC 4649. We estimate the background contamination using several blank fields. Our results suggest that IR colours can be effectively used to differentiate between sources in the galaxy and background ones. In particular we find that sources having AGN like colours are indeed consistent with being background AGNs. For sources with non AGN like colours we compute the distribution of flux and normalised distance from the centre which is found to be of a power-law form. Although our sample size is small, the power-law index for the galaxies are different indicating perhaps that the galaxy environment may be playing a part in their origin and nature.

Caresoil: A multidisciplinar Project to characterize, remediate, monitor and evaluate the risk of contaminated soils in Madrid (Spain)

NASA Astrophysics Data System (ADS)

Muñoz-Martín, Alfonso; Antón, Loreto; Granja, Jose Luis; Villarroya, Fermín; Montero, Esperanza; Rodríguez, Vanesa

2016-04-01

Soil contamination can come from diffuse sources (air deposition, agriculture, etc.) or local sources, these last being related to anthropogenic activities that are potentially soil contaminating activities. According to data from the EU, in Spain, and particularly for the Autonomous Community of Madrid, it can be considered that heavy metals, toxic organic compounds (including Non Aqueous Phases Liquids, NAPLs) and combinations of both are the main problem of point sources of soil contamination in our community. The five aspects that will be applied in Caresoil Program (S2013/MAE-2739) in the analysis and remediation of a local soil contamination are: 1) the location of the source of contamination and characterization of soil and aquifer concerned, 2) evaluation of the dispersion of the plume, 3) application of effective remediation techniques, 4) monitoring the evolution of the contaminated soil and 5) risk analysis throughout this process. These aspects involve advanced technologies (hydrogeology, geophysics, geochemistry,...) that require new developing of knowledge, being necessary the contribution of several researching groups specialized in the fields previously cited, as they are those integrating CARESOIL Program. Actually two cases concerning hydrocarbon spills, as representative examples of soil local contamination in Madrid area, are being studied. The first is being remediated and we are monitoring this process to evaluate its effectiveness. In the second location we are defining the extent of contamination in soil and aquifer to define the most effective remediation technique.

Using vadose zone data and spatial statistics to assess the impact of cultivated land and dairy waste lagoons on groundwater contamination

NASA Astrophysics Data System (ADS)

Baram, S.; Ronen, Z.; Kurtzman, D.; Peeters, A.; Dahan, O.

2013-12-01

Land cultivation and dairy waste lagoons are considered to be nonpoint and point sources of groundwater contamination by chloride (Cl-) and nitrate (NO3-). The objective of this work is to introduce a methodology to assess the past and future impacts of such agricultural activities on regional groundwater quality. The method is based on mass balances and on spatial statistical analysis of Cl- and NO3-concentration distributions in the saturated and unsaturated zones. The method enables quantitative analysis of the relation between the locations of pollution point sources and the spatial variability in Cl- and NO3- concentrations in groundwater. The method was applied to the Beer-Tuvia region, Israel, where intensive dairy farming along with land cultivation has been practiced for over 50 years above the local phreatic aquifer. Mass balance calculations accounted for the various groundwater recharge and abstraction sources and sinks in the entire region. The mass balances showed that leachates from lagoons and the cultivated land have contributed 6.0 and 89.4 % of the total mass of Cl- added to the aquifer and 12.6 and 77.4 % of the total mass of NO3-. The chemical composition of the aquifer and vadose zone water suggested that irrigated agricultural activity in the region is the main contributor of Cl- and NO3- to the groundwater. A low spatial correlation between the Cl- and NO3- concentrations in the groundwater and the on-land location of the dairy farms strengthened this assumption, despite the dairy waste lagoon being a point source for groundwater contamination by Cl- and NO3-. Results demonstrate that analyzing vadose zone and groundwater data by spatial statistical analysis methods can significantly contribute to the understanding of the relations between groundwater contaminating sources, and to assessing appropriate remediation steps.

Oil spill contamination probability in the southeastern Levantine basin.

PubMed

Goldman, Ron; Biton, Eli; Brokovich, Eran; Kark, Salit; Levin, Noam

2015-02-15

Recent gas discoveries in the eastern Mediterranean Sea led to multiple operations with substantial economic interest, and with them there is a risk of oil spills and their potential environmental impacts. To examine the potential spatial distribution of this threat, we created seasonal maps of the probability of oil spill pollution reaching an area in the Israeli coastal and exclusive economic zones, given knowledge of its initial sources. We performed simulations of virtual oil spills using realistic atmospheric and oceanic conditions. The resulting maps show dominance of the alongshore northerly current, which causes the high probability areas to be stretched parallel to the coast, increasing contamination probability downstream of source points. The seasonal westerly wind forcing determines how wide the high probability areas are, and may also restrict these to a small coastal region near source points. Seasonal variability in probability distribution, oil state, and pollution time is also discussed. Copyright © 2014 Elsevier Ltd. All rights reserved.

Characterization of streamflow, water quality, and instantaneous dissolved solids, selenium, and uranium loads in selected reaches of the Arkansas River, southeastern Colorado, 2009-2010

USGS Publications Warehouse

Ivahnenko, Tamara; Ortiz, Roderick F.; Stogner, Sr., Robert W.

2013-01-01

As a result of continued water-quality concerns in the Arkansas River, including metal contamination from historical mining practices, potential effects associated with storage and movement of water, point- and nonpoint-source contamination, population growth, storm-water flows, and future changes in land and water use, the Arkansas River Basin Regional Resource Planning Group (RRPG) developed a strategy to address these issues. As such, a cooperative strategic approach to address the multiple water-quality concerns within selected reaches of the Arkansas River was developed to (1) identify stream reaches where stream-aquifer interactions have a pronounced effect on water quality and (or) where reactive transport, and physical and (or) chemical alteration of flow during conveyance, is occurring, (2) quantify loading from point sources, and (3) determine source areas and mass loading for selected constituents. (To see the complete abstract, open Report PDF.)

Source-water susceptibility assessment in Texas—Approach and methodology

USGS Publications Warehouse

Ulery, Randy L.; Meyer, John E.; Andren, Robert W.; Newson, Jeremy K.

2011-01-01

Public water systems provide potable water for the public's use. The Safe Drinking Water Act amendments of 1996 required States to prepare a source-water susceptibility assessment (SWSA) for each public water system (PWS). States were required to determine the source of water for each PWS, the origin of any contaminant of concern (COC) monitored or to be monitored, and the susceptibility of the public water system to COC exposure, to protect public water supplies from contamination. In Texas, the Texas Commission on Environmental Quality (TCEQ) was responsible for preparing SWSAs for the more than 6,000 public water systems, representing more than 18,000 surface-water intakes or groundwater wells. The U.S. Geological Survey (USGS) worked in cooperation with TCEQ to develop the Source Water Assessment Program (SWAP) approach and methodology. Texas' SWAP meets all requirements of the Safe Drinking Water Act and ultimately provides the TCEQ with a comprehensive tool for protection of public water systems from contamination by up to 247 individual COCs. TCEQ staff identified both the list of contaminants to be assessed and contaminant threshold values (THR) to be applied. COCs were chosen because they were regulated contaminants, were expected to become regulated contaminants in the near future, or were unregulated but thought to represent long-term health concerns. THRs were based on maximum contaminant levels from U.S. Environmental Protection Agency (EPA)'s National Primary Drinking Water Regulations. For reporting purposes, COCs were grouped into seven contaminant groups: inorganic compounds, volatile organic compounds, synthetic organic compounds, radiochemicals, disinfection byproducts, microbial organisms, and physical properties. Expanding on the TCEQ's definition of susceptibility, subject-matter expert working groups formulated the SWSA approach based on assumptions that natural processes and human activities contribute COCs in quantities that vary in space and time; that increased levels of COC-producing activities within a source area may increase susceptibility to COC exposure; and that natural and manmade conditions within the source area may increase, decrease, or have no observable effect on susceptibility to COC exposure. Incorporating these assumptions, eight SWSA components were defined: identification, delineation, intrinsic susceptibility, point- and nonpoint-source susceptibility, contaminant occurrence, area-of-primary influence, and summary components. Spatial datasets were prepared to represent approximately 170 attributes or indicators used in the assessment process. These primarily were static datasets (approximately 46 gigabytes (GB) in size). Selected datasets such as PWS surface-water-intake or groundwater-well locations and potential source of contamination (PSOC) locations were updated weekly. Completed assessments were archived, and that database is approximately 10 GB in size. SWSA components currently (2011) are implemented in the Source Water Assessment Program-Decision Support System (SWAP-DSS) computer software, specifically developed to produce SWSAs. On execution of the software, the components work to identify the source of water for the well or intake, assess intrinsic susceptibility of the water- supply source, assess susceptibility to contamination with COCs from point and nonpoint sources, identify any previous detections of COCs from existing water-quality databases, and summarize the results. Each water-supply source's susceptibility is assessed, source results are weighted by source capacity (when a PWS has multiple sources), and results are combined into a single SWSA for the PWS.'SWSA reports are generated using the software; during 2003, more than 6,000 reports were provided to PWS operators and the public. The ability to produce detailed or summary reports for individual sources, and detailed or summary reports for a PWS, by COC or COC group was a unique capability of SWAP-DSS. In 2004, the TCEQ began a rotating schedule for SWSA wherein one-third of PWSs statewide would be assessed annually, or sooner if protection-program activities deemed it necessary, and that schedule has continued to the present. Cooperative efforts by the TCEQ and the USGS for SWAP software maintenance and enhancements ended in 2011 with the TCEQ assuming responsibility for all tasks.

UTILIZATION OF LANDSCAPE INDICATORS TO MODEL WATER QUALITY

EPA Science Inventory

Many water-bodies within the United States are contaminated by, non-point source (NFS) pollution, which is defined as those materials posing a threat to water quality arising from a number of individual sources and diffused through hydrologic processes. One such NPS pollu...

Null-space Monte Carlo particle tracking to assess groundwater PCE (Tetrachloroethene) diffuse pollution in north-eastern Milan functional urban area.

PubMed

Alberti, Luca; Colombo, Loris; Formentin, Giovanni

2018-04-15

The Lombardy Region in Italy is one of the most urbanized and industrialized areas in Europe. The presence of countless sources of groundwater pollution is therefore a matter of environmental concern. The sources of groundwater contamination can be classified into two different categories: 1) Point Sources (PS), which correspond to areas releasing plumes of high concentrations (i.e. hot-spots) and 2) Multiple-Point Sources (MPS) consisting in a series of unidentifiable small sources clustered within large areas, generating an anthropogenic diffuse contamination. The latter category frequently predominates in European Functional Urban Areas (FUA) and cannot be managed through standard remediation techniques, mainly because detecting the many different source areas releasing small contaminant mass in groundwater is unfeasible. A specific legislative action has been recently enacted at Regional level (DGR IX/3510-2012), in order to identify areas prone to anthropogenic diffuse pollution and their level of contamination. With a view to defining a management plan, it is necessary to find where MPS are most likely positioned. This paper describes a methodology devised to identify the areas with the highest likelihood to host potential MPS. A groundwater flow model was implemented for a pilot area located in the Milan FUA and through the PEST code, a Null-Space Monte Carlo method was applied in order to generate a suite of several hundred hydraulic conductivity field realizations, each maintaining the model in a calibrated state and each consistent with the modelers' expert-knowledge. Thereafter, the MODPATH code was applied to generate back-traced advective flowpaths for each of the models built using the conductivity field realizations. Maps were then created displaying the number of backtracked particles that crossed each model cell in each stochastic calibrated model. The result is considered to be representative of the FUAs areas with the highest likelihood to host MPS responsible for diffuse contamination. Copyright © 2017 Elsevier B.V. All rights reserved.

Association of Supply Type with Fecal Contamination of Source Water and Household Stored Drinking Water in Developing Countries: A Bivariate Meta-analysis

PubMed Central

Bain, Robert E.S.; Cronk, Ryan; Wright, Jim A.; Bartram, Jamie

2015-01-01

Background Access to safe drinking water is essential for health. Monitoring access to drinking water focuses on water supply type at the source, but there is limited evidence on whether quality differences at the source persist in water stored in the household. Objectives We assessed the extent of fecal contamination at the source and in household stored water (HSW) and explored the relationship between contamination at each sampling point and water supply type. Methods We performed a bivariate random-effects meta-analysis of 45 studies, identified through a systematic review, that reported either the proportion of samples free of fecal indicator bacteria and/or individual sample bacteria counts for source and HSW, disaggregated by supply type. Results Water quality deteriorated substantially between source and stored water. The mean percentage of contaminated samples (noncompliance) at the source was 46% (95% CI: 33, 60%), whereas mean noncompliance in HSW was 75% (95% CI: 64, 84%). Water supply type was significantly associated with noncompliance at the source (p < 0.001) and in HSW (p = 0.03). Source water (OR = 0.2; 95% CI: 0.1, 0.5) and HSW (OR = 0.3; 95% CI: 0.2, 0.8) from piped supplies had significantly lower odds of contamination compared with non-piped water, potentially due to residual chlorine. Conclusions Piped water is less likely to be contaminated compared with other water supply types at both the source and in HSW. A focus on upgrading water services to piped supplies may help improve safety, including for those drinking stored water. Citation Shields KF, Bain RE, Cronk R, Wright JA, Bartram J. 2015. Association of supply type with fecal contamination of source water and household stored drinking water in developing countries: a bivariate meta-analysis. Environ Health Perspect 123:1222–1231; http://dx.doi.org/10.1289/ehp.1409002 PMID:25956006

Influence of Diffused Sourcers of Water Pollution In The Basin of Volga River

NASA Astrophysics Data System (ADS)

Vasilchenco, O.

The intensive development of industry and agriculture, great growth of cities in the last decades result in an increase of the nature water consumption and deterioration. Different anthropogenic load change characteristics of water objects regime and de- pletion and qualitative degradation of water resources. Sources of pollution are divided on two classes: controlled and uncontrolled. The first includes industrial and domestic wastewater disposal. Their discharge and concentration of pollutants are quite stable. These sources of pollution are identified as "point". Surface run-off from of cities, industrial platforms, agricultural object, navigation, recreation are not controlled have dispersed nature and are identification as diffuse. Pollution from such sources is es- timates by computation. Quantitative assumption of pollution amounts reaches water objects is complicated and independent problem. The significant amount of full-scale observations and information processes of concerning dissolved and fluidized frag- ments movement are required. According to available guidelines the part of the pollu- tant entering water objects, is about 1-10For estimation of pollution mass and transport are mathematical modeling. Preliminary calculations of contaminants transport for different territories under an- thropogenic impact of river-Volga basin were made either for point sources of pol- lution or for non-point. Received data made it possible to analyze the correlation of contaminant volumes, coming from different sources pollution.

Contaminant source and release history identification in groundwater: A multi-step approach

NASA Astrophysics Data System (ADS)

Gzyl, G.; Zanini, A.; Frączek, R.; Kura, K.

2014-02-01

The paper presents a new multi-step approach aiming at source identification and release history estimation. The new approach consists of three steps: performing integral pumping tests, identifying sources, and recovering the release history by means of a geostatistical approach. The present paper shows the results obtained from the application of the approach within a complex case study in Poland in which several areal sources were identified. The investigated site is situated in the vicinity of a former chemical plant in southern Poland in the city of Jaworzno in the valley of the Wąwolnica River; the plant has been in operation since the First World War producing various chemicals. From an environmental point of view the most relevant activity was the production of pesticides, especially lindane. The application of the multi-step approach enabled a significant increase in the knowledge of contamination at the site. Some suspected contamination sources have been proven to have minor effect on the overall contamination. Other suspected sources have been proven to have key significance. Some areas not taken into consideration previously have now been identified as key sources. The method also enabled estimation of the magnitude of the sources and, a list of the priority reclamation actions will be drawn as a result. The multi-step approach has proven to be effective and may be applied to other complicated contamination cases. Moreover, the paper shows the capability of the geostatistical approach to manage a complex real case study.

UTILIZATION OF LANDSCAPE INDICATORS TO MODEL WATERSHED IMPAIRMENT

EPA Science Inventory

Many water-bodies within the United States are contaminated by non-point source (NPS) pollution, which is defined as those materials posing a threat to water quality arising from a number of individual sources and diffused through hydrologic 13romses. One such NPS
pol...

Contamination sources, serogroups, biofilm-forming ability and biocide resistance of Listeria monocytogenes persistent in tilapia-processing facilities.

PubMed

Vázquez-Sánchez, Daniel; Galvão, Juliana Antunes; Oetterer, Marília

2017-11-01

The major contamination sources, serogroups, biofilm-forming ability and biocide resistance of Listeria monocytogenes persistent in tilapia-processing facilities were assessed. Twenty-five processing-control points were examined twice in two factories, including whole tilapias, frozen fillets, water and food-contact surfaces. L. monocytogenes were detected in 4 and 20% of points of Factory A and B respectively, but at low concentrations. Contamination was due to inadequate handling of tilapias in the slaughter room of Factory A and to the application of ineffective sanitizing procedures in Factory B. Seven strains were characterized by RAPD-PCR using primers HLWL85, OPM-01 and DAF4. Genotypic similarity allowed tracing the contamination source of tilapia fillets in Factory B and detecting a prevalent strain in Brazilian tilapia-processing facilities. The serogroup II (including the serotype 1/2c) was the most frequently found, followed by serogroup I (1/2a) and III (1/2b), whereas the serotype 4b was not detected. All strains showed high biofilm-forming ability on stainless steel and polystyrene, but biofilm formation was positively correlated with the type of origin surface. Biofilms were highly resistant to peracetic acid and sodium hypochlorite, being required doses higher than those recommended by manufacturers to be eradicated. Peracetic acid was more effective than sodium hypochlorite, but the use of disinfectants with similar mechanisms of action increases the risk of cross-resistance. Case-by-case approaches are thus recommended to determine the sources and degree of contamination present in each factory, which would allow applying precise responses to control the persistence of bacterial pathogens such as L. monocytogenes .

Tidal salt marsh sediment in California, USA. Part 1: occurrence and sources of organic contaminants.

PubMed

Hwang, Hyun-Min; Green, Peter G; Young, Thomas M

2006-08-01

Surface sediment samples (0-5 cm) from five tidal marshes along the coast of California, USA were analyzed for organic pollutants to investigate their relationship to land use, current distribution within marshes, and possible sources. Among the study areas, Stege Marsh, located in San Francisco Bay, was the most contaminated. Compared to San Francisco Bay, Stege Marsh had much higher levels of organic contaminants such as PCBs (polychlorinated biphenyls), DDTs, and chlordanes. At reference marshes (Tom's Point and Walker Creek in Tomales Bay), organic contaminants in sediments were very low. While PAHs (polycyclic aromatic hydrocarbons) were found at all of the study areas (22-13,600 ng g(-1)), measurable concentrations of PCBs were found only in the sediments from Stege Marsh (80-9,940 ng g(-1)). Combustion related (pyrogenic) high molecular weight PAHs were dominant in sediments from Stege and Carpinteria Marshes, while in sediments from Tom's Point and Walker Creek petroleum related (petrogenic) low molecular weight PAHs and alkyl-substituted PAHs were much more abundant than pyrogenic PAHs. PCB congener patterns in all of the Stege Marsh samples were the same and revealed that Aroclor 1248 was a predominant source. In all marshes, the sum of DDE and DDD accounted for more than 90% of total DDTs, indicating that DDT has degraded significantly. The ratios of p,p'-DDE to p,p'-DDD in sediments from Stege Marsh provide evidence of possible previous use of technical DDD. Chlordane ratios indicated that chlordanes have degraded slightly. Bis(2-ethylhexyl)phthalate (280-32,000 ng g(-1)) was the most abundant phthalate. The data indicates that Stege Marsh may be a source of contaminants that continue to be discharged into San Francisco Bay.

Modelling remediation scenarios in historical mining catchments.

PubMed

Gamarra, Javier G P; Brewer, Paul A; Macklin, Mark G; Martin, Katherine

2014-01-01

Local remediation measures, particularly those undertaken in historical mining areas, can often be ineffective or even deleterious because erosion and sedimentation processes operate at spatial scales beyond those typically used in point-source remediation. Based on realistic simulations of a hybrid landscape evolution model combined with stochastic rainfall generation, we demonstrate that similar remediation strategies may result in differing effects across three contrasting European catchments depending on their topographic and hydrologic regimes. Based on these results, we propose a conceptual model of catchment-scale remediation effectiveness based on three basic catchment characteristics: the degree of contaminant source coupling, the ratio of contaminated to non-contaminated sediment delivery, and the frequency of sediment transport events.

Source partitioning of anthropogenic groundwater nitrogen in a mixed-use landscape, Tutuila, American Samoa

NASA Astrophysics Data System (ADS)

Shuler, Christopher K.; El-Kadi, Aly I.; Dulai, Henrietta; Glenn, Craig R.; Fackrell, Joseph

2017-12-01

This study presents a modeling framework for quantifying human impacts and for partitioning the sources of contamination related to water quality in the mixed-use landscape of a small tropical volcanic island. On Tutuila, the main island of American Samoa, production wells in the most populated region (the Tafuna-Leone Plain) produce most of the island's drinking water. However, much of this water has been deemed unsafe to drink since 2009. Tutuila has three predominant anthropogenic non-point-groundwater-pollution sources of concern: on-site disposal systems (OSDS), agricultural chemicals, and pig manure. These sources are broadly distributed throughout the landscape and are located near many drinking-water wells. Water quality analyses show a link between elevated levels of total dissolved groundwater nitrogen (TN) and areas with high non-point-source pollution density, suggesting that TN can be used as a tracer of groundwater contamination from these sources. The modeling framework used in this study integrates land-use information, hydrological data, and water quality analyses with nitrogen loading and transport models. The approach utilizes a numerical groundwater flow model, a nitrogen-loading model, and a multi-species contaminant transport model. Nitrogen from each source is modeled as an independent component in order to trace the impact from individual land-use activities. Model results are calibrated and validated with dissolved groundwater TN concentrations and inorganic δ15N values, respectively. Results indicate that OSDS contribute significantly more TN to Tutuila's aquifers than other sources, and thus should be prioritized in future water-quality management efforts.

Field demonstration of foam injection to confine a chlorinated solvent source zone.

PubMed

Portois, Clément; Essouayed, Elyess; Annable, Michael D; Guiserix, Nathalie; Joubert, Antoine; Atteia, Olivier

2018-05-01

A novel approach using foam to manage hazardous waste was successfully demonstrated under active site conditions. The purpose of the foam was to divert groundwater flow, that would normally enter the source zone area, to reduce dissolved contaminant release to the aquifer. During the demonstration, foam was pre generated and directly injected surrounding the chlorinated solvent source zone. Despite the constraints related to the industrial activities and non-optimal position of the injection points, the applicability and effectiveness of the approach have been highlighted using multiple metrics. A combination of measurements and modelling allowed definition of the foam extent surrounding each injection point, and this appears to be the critical metric to define the success of the foam injection approach. Information on the transport of chlorinated solvents in groundwater showed a decrease of contaminant flux by a factor of 4.4 downstream of the confined area. The effective permeability reduction was maintained over a period of three months. The successful containment provides evidence for consideration of the use of foam to improve traditional flushing techniques, by increasing the targeting of contaminants by remedial agents. Copyright © 2018 Elsevier B.V. All rights reserved.

Contaminant point source localization error estimates as functions of data quantity and model quality

NASA Astrophysics Data System (ADS)

Hansen, Scott K.; Vesselinov, Velimir V.

2016-10-01

We develop empirically-grounded error envelopes for localization of a point contamination release event in the saturated zone of a previously uncharacterized heterogeneous aquifer into which a number of plume-intercepting wells have been drilled. We assume that flow direction in the aquifer is known exactly and velocity is known to within a factor of two of our best guess from well observations prior to source identification. Other aquifer and source parameters must be estimated by interpretation of well breakthrough data via the advection-dispersion equation. We employ high performance computing to generate numerous random realizations of aquifer parameters and well locations, simulate well breakthrough data, and then employ unsupervised machine optimization techniques to estimate the most likely spatial (or space-time) location of the source. Tabulating the accuracy of these estimates from the multiple realizations, we relate the size of 90% and 95% confidence envelopes to the data quantity (number of wells) and model quality (fidelity of ADE interpretation model to actual concentrations in a heterogeneous aquifer with channelized flow). We find that for purely spatial localization of the contaminant source, increased data quantities can make up for reduced model quality. For space-time localization, we find similar qualitative behavior, but significantly degraded spatial localization reliability and less improvement from extra data collection. Since the space-time source localization problem is much more challenging, we also tried a multiple-initial-guess optimization strategy. This greatly enhanced performance, but gains from additional data collection remained limited.

A simplified approach for monitoring hydrophobic organic contaminants associated with suspended sediment: Methodology and applications

USGS Publications Warehouse

Mahler, B.J.; Van Metre, P.C.

2003-01-01

Hydrophobic organic contaminants, although frequently detected in bed sediment and in aquatic biota, are rarely detected in whole-water samples, complicating determination of their occurrence, load, and source. A better approach for the investigation of hydrophobic organic contaminants is the direct analysis of sediment in suspension, but procedures for doing so are expensive and cumbersome. We describe a simple, inexpensive methodology for the dewatering of sediment and present the results of two case studies. Isolation of a sufficient mass of sediment for analyses of organochlorine compounds and PAHs is obtained by in-line filtration of large volumes of water. The sediment is removed from the filters and analyzed directly by standard laboratory methods. In the first case study, suspended-sediment sampling was used to determine occurrence, loads, and yields of contaminants in urban runoff affecting biota in Town Lake, Austin, TX. The second case study used suspended-sediment sampling to locate a point source of PCBs in the Donna Canal in south Texas, where fish are contaminated with PCBs. The case studies demonstrate that suspended-sediment sampling can be an effective tool for determining the occurrence, load, and source of hydrophobic organic contaminants in transport.

COMPARISON OF OZONE INDICATORS MONITORED AT CASTNET AND RURALLY - DESIGNATED SLAMS SITES

EPA Science Inventory

Many water-bodies within the United States are contaminated by non-point source (NPS) pollution, which is defined as those materials posing a threat to water quality arising from a number of individual sources and diffused through hydrologic 13romses. One such NPS pollutant is fe...

Standardised survey method for identifying catchment risks to water quality.

PubMed

Baker, D L; Ferguson, C M; Chier, P; Warnecke, M; Watkinson, A

2016-06-01

This paper describes the development and application of a systematic methodology to identify and quantify risks in drinking water and recreational catchments. The methodology assesses microbial and chemical contaminants from both diffuse and point sources within a catchment using Escherichia coli, protozoan pathogens and chemicals (including fuel and pesticides) as index contaminants. Hazard source information is gathered by a defined sanitary survey process involving use of a software tool which groups hazards into six types: sewage infrastructure, on-site sewage systems, industrial, stormwater, agriculture and recreational sites. The survey estimates the likelihood of the site affecting catchment water quality, and the potential consequences, enabling the calculation of risk for individual sites. These risks are integrated to calculate a cumulative risk for each sub-catchment and the whole catchment. The cumulative risks process accounts for the proportion of potential input sources surveyed and for transfer of contaminants from upstream to downstream sub-catchments. The output risk matrices show the relative risk sources for each of the index contaminants, highlighting those with the greatest impact on water quality at a sub-catchment and catchment level. Verification of the sanitary survey assessments and prioritisation is achieved by comparison with water quality data and microbial source tracking.

Reconstructing Contaminant Deposition in a San Francisco Bay Marina, California

PubMed Central

Love, Adam H.; Esser, Bradley K.; Hunt, James R.

2010-01-01

Two sediment cores were collected from a marina in the San Francisco Bay to characterize historical sediment contamination resulting from the direct discharge of industrial wastewater from Naval Air Station Alameda. Depth profiles of trace metals, petroleum hydrocarbons, and radionuclides were determined with a 12-cm spacing down to a depth of 120 cm. The chronology of sediment accumulation is established by depth profiles of sedimentary time markers in conjunction with information on site history. The traditional approach of determining sediment accumulation rates by measuring atmospheric 210Pb deposition was obscured by a larger source of 210Pb in the sediments from the decay of anthropogenic 226Ra, likely from luminescent paints used at this facility and released to the marina. The sedimentation rates inferred from the data indicate that the greatest amount of contamination by trace metals and petroleum hydrocarbons took place between 1940 and 1960. In addition, anthropogenic 226Ra activities are positively correlated with some of the contaminants in the sediments, allowing the wastewater discharged from the facility to be distinguished from baywide contamination. In locations such as this, where there is a complex history of contaminant deposition, a source-specific tracer may be the only feasible method of attributing historical contamination to a point source. PMID:20333267

Systems Reliability Framework for Surface Water Sustainability and Risk Management

NASA Astrophysics Data System (ADS)

Myers, J. R.; Yeghiazarian, L.

2016-12-01

With microbial contamination posing a serious threat to the availability of clean water across the world, it is necessary to develop a framework that evaluates the safety and sustainability of water systems in respect to non-point source fecal microbial contamination. The concept of water safety is closely related to the concept of failure in reliability theory. In water quality problems, the event of failure can be defined as the concentration of microbial contamination exceeding a certain standard for usability of water. It is pertinent in watershed management to know the likelihood of such an event of failure occurring at a particular point in space and time. Microbial fate and transport are driven by environmental processes taking place in complex, multi-component, interdependent environmental systems that are dynamic and spatially heterogeneous, which means these processes and therefore their influences upon microbial transport must be considered stochastic and variable through space and time. A physics-based stochastic model of microbial dynamics is presented that propagates uncertainty using a unique sampling method based on artificial neural networks to produce a correlation between watershed characteristics and spatial-temporal probabilistic patterns of microbial contamination. These results are used to address the question of water safety through several sustainability metrics: reliability, vulnerability, resilience and a composite sustainability index. System reliability is described uniquely though the temporal evolution of risk along watershed points or pathways. Probabilistic resilience describes how long the system is above a certain probability of failure, and the vulnerability metric describes how the temporal evolution of risk changes throughout a hierarchy of failure levels. Additionally our approach allows for the identification of contributions in microbial contamination and uncertainty from specific pathways and sources. We expect that this framework will significantly improve the efficiency and precision of sustainable watershed management strategies through providing a better understanding of how watershed characteristics and environmental parameters affect surface water quality and sustainability. With microbial contamination posing a serious threat to the availability of clean water across the world, it is necessary to develop a framework that evaluates the safety and sustainability of water systems in respect to non-point source fecal microbial contamination. The concept of water safety is closely related to the concept of failure in reliability theory. In water quality problems, the event of failure can be defined as the concentration of microbial contamination exceeding a certain standard for usability of water. It is pertinent in watershed management to know the likelihood of such an event of failure occurring at a particular point in space and time. Microbial fate and transport are driven by environmental processes taking place in complex, multi-component, interdependent environmental systems that are dynamic and spatially heterogeneous, which means these processes and therefore their influences upon microbial transport must be considered stochastic and variable through space and time. A physics-based stochastic model of microbial dynamics is presented that propagates uncertainty using a unique sampling method based on artificial neural networks to produce a correlation between watershed characteristics and spatial-temporal probabilistic patterns of microbial contamination. These results are used to address the question of water safety through several sustainability metrics: reliability, vulnerability, resilience and a composite sustainability index. System reliability is described uniquely though the temporal evolution of risk along watershed points or pathways. Probabilistic resilience describes how long the system is above a certain probability of failure, and the vulnerability metric describes how the temporal evolution of risk changes throughout a hierarchy of failure levels. Additionally our approach allows for the identification of contributions in microbial contamination and uncertainty from specific pathways and sources. We expect that this framework will significantly improve the efficiency and precision of sustainable watershed management strategies through providing a better understanding of how watershed characteristics and environmental parameters affect surface water quality and sustainability.

DOE Office of Scientific and Technical Information (OSTI.GOV)

None, None

Operations of Sandia National Laboratories, Nevada (SNL/NV) at the Tonopah Test Range (TTR) resulted in no planned point radiological releases during 1996. Other releases from SNL/NV included diffuse transuranic sources consisting of the three Clean Slate sites. Air emissions from these sources result from wind resuspension of near-surface transuranic contaminated soil particulates. The total area of contamination has been estimated to exceed 20 million square meters. Soil contamination was documented in an aerial survey program in 1977 (EG&G 1979). Surface contamination levels were generally found to be below 400 pCi/g of combined plutonium-238, plutonium-239, plutonium-240, and americium-241 (i.e., transuranic) activity.more » Hot spot areas contain up to 43,000 pCi/g of transuranic activity. Recent measurements confirm the presence of significant levels of transuranic activity in the surface soil. An annual diffuse source term of 0.39 Ci of transuranic material was calculated for the cumulative release from all three Clean Slate sites. A maximally exposed individual dose of 1.1 mrem/yr at the TTR airport area was estimated based on the 1996 diffuse source release amounts and site-specific meteorological data. A population dose of 0.86 person-rem/yr was calculated for the local residents. Both dose values were attributable to inhalation of transuranic contaminated dust.« less

Determination of MeHg sources to fish in the St. Louis River, MN, USA, using Hg stable isotopes

EPA Science Inventory

Mercury contamination in the Great Lakes region has become a prevalent concern due to elevated methylmercury (MeHg) levels in fish. While atmospheric deposition of Hg is ubiquitous, releases from legacy point-sources give rise to numerous Areas of Concern (AOCs) across the Great ...

Occurrence of perfluoroalkyl sulfonates and carboxylates in German drinking water sources compared to other countries.

PubMed

Lange, F T; Wenz, M; Schmidt, C K; Brauch, H-J

2007-01-01

Different homologues of C4 to C8 perfluoroalkyl carboxylates (PFCAs) and perfluoroalkyl sulfonates (PFASs) were detected in German surface waters, bank filtrates, artificially recharged groundwaters, and drinking waters. If no point sources are located nearby, the typically measured levels are in the low ng/L range. In the presence of point sources, such as a fluorochemical production site, a leaching agricultural fertilizer contaminated with PFCAs and PFASs, or drained PFC containing fire-fighting foams, much higher concentrations in the microg/L range occur. This situation is similar in Germany and other countries.

Reduction of non-point source contaminants associated with road-deposited sediments by sweeping.

PubMed

Kim, Do-Gun; Kang, Hee-Man; Ko, Seok-Oh

2017-09-19

Road-deposited sediments (RDS) on an expressway, residual RDS collected after sweeping, and RDS removed by means of sweeping were analyzed to evaluate the degree to which sweeping removed various non-point source contaminants. The total RDS load was 393.1 ± 80.3 kg/km and the RDS, residual RDS, and swept RDS were all highly polluted with organics, nutrients, and metals. Among the metals studied, Cu, Zn, Pb, Ni, Ca, and Fe were significantly enriched, and most of the contaminants were associated with particles within the size range from 63 μm to 2 mm. Sweeping reduced RDS and its associated contaminants by 33.3-49.1% on average. We also measured the biological oxygen demand (BOD) of RDS in the present work, representing to our knowledge the first time that this has been done; we found that RDS contains a significant amount of biodegradable organics and that the reduction of BOD by sweeping was higher than that of other contaminants. Significant correlations were found between the contaminants measured, indicating that the organics and the metals originated from both exhaust and non-exhaust particles. Meanwhile, the concentrations of Cu and Ni were higher in 63 μm-2 mm particles than in smaller particles, suggesting that some metals in RDS likely exist intrinsically in particles, rather than only as adsorbates on particle surfaces. Overall, the results in this study showed that sweeping to collect RDS can be a good alternative for reduction of contaminants in runoff.

Managing commercial and light-industrial discharges to POTWs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fink, R.G.

1993-02-01

Discharging commercial and light-industrial wastewater to a publicly owned treatment works (POTW) is risky business. Pretreating wastewater using traditional methods may leave a wastestream's originator vulnerable to fines, civil and criminal punishment, cleanup costs, and cease-and-desist orders. EPA has tightened regulations applying to discharges from POTWs, which, in turn, are looking to industrial and commercial discharge sources to determine responsibility for toxic contaminants. Although EPA in the past focused on large point sources of contamination, the Agency has shifted its emphasis to smaller and more diverse nonpoint sources. One result is that POTWs no longer act as buffers for light-industrialmore » and commercial wastewater dischargers.« less

Legacy source of mercury in an urban stream-wetland ecosystem in central North Carolina, USA.

PubMed

Deonarine, Amrika; Hsu-Kim, Heileen; Zhang, Tong; Cai, Yong; Richardson, Curtis J

2015-11-01

In the United States, aquatic mercury contamination originates from point and non-point sources to watersheds. Here, we studied the contribution of mercury in urban runoff derived from historically contaminated soils and the subsequent production of methylmercury in a stream-wetland complex (Durham, North Carolina), the receiving water of this runoff. Our results demonstrated that the mercury originated from the leachate of grass-covered athletic fields. A fraction of mercury in this soil existed as phenylmercury, suggesting that mercurial anti-fungal compounds were historically applied to this soil. Further downstream in the anaerobic sediments of the stream-wetland complex, a fraction (up to 9%) of mercury was converted to methylmercury, the bioaccumulative form of the metal. Importantly, the concentrations of total mercury and methylmercury were reduced to background levels within the stream-wetland complex. Overall, this work provides an example of a legacy source of mercury that should be considered in urban watershed models and watershed management. Copyright © 2014 Elsevier Ltd. All rights reserved.

Treatment of Chlorinated Solvents in Groundwater Beneath an Occupied Building at the Young-Rainey STAR Center, Pinellas, FL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daniel, Joe; Surovchak, Scott; Tabor, Charles

Groundwater contamination, consisting of two dissolved-phase plumes originating from chlorinated solvent source areas, in the southeastern portion of the Young- Rainey Star Center (also known as the Pinellas County, Florida, Site) in Largo, Florida, has migrated beyond the property boundary, beneath the roadways, and beneath adjacent properties to the south and east. Groundwater contamination will persist as long as the onsite contaminant source remains. The origin of the contamination appears to be multiple long-term point sources beneath Building 100, a 4.5 ha (11 acre) building that housed manufacturing facilities during US DOE operations at the site. The site is nowmore » owned by Pinellas County, and most of the space inside the building is leased to private companies, so DOE chose not to conduct characterization or remediation through the floor of the building, instead choosing to conduct all work from outside the building. Injection of emulsified soybean oil and a microbial culture has been used at other areas of the site to accelerate naturally occurring bacterial processes that degrade groundwater contaminants to harmless compounds, and that same approach was chosen for this task. The technical approach consisted of installing horizontal wells from outside the building footprint, extending through and around the identified subsurface treatment areas, and terminating beneath the building. Two 107 m (350 ft) long wells, two 122 m (400 ft) long wells, and four 137 m (450 ft) long wells have been installed to intersect the inferred source areas and confirmed contaminant plumes beneath the building. DOE then injected emulsified vegetable oil and a microbial culture into the horizontal wells at each of several target areas beneath the building where the highest groundwater contaminant concentrations have been detected. The target areas are the northwest corner of the building between the old drum storage pad locations and monitoring well PIN12-S35B, the vicinity of former monitoring well PIN12-S57B, and hydraulically upgradient from the south plume and the east plume at the points where they exit from beneath the building. We describe the details of designing and constructing horizontal injection wells for bioremediation beneath a large, occupied industrial production facility, including lessons learned; technical, logistical, and environmental challenges; community relations; and regulatory relations. Because of the expected lag in biological acclimation and response, distance between the treatment areas and associated monitoring points, and low groundwater velocity, it will likely be years before the full impact of the project will be realized.« less

Stochastic Management of Non-Point Source Contamination: Joint Impact of Aquifer Heterogeneity and Well Characteristics

NASA Astrophysics Data System (ADS)

Henri, C. V.; Harter, T.

2017-12-01

Agricultural activities are recognized as the preeminent origin of non-point source (NPS) contamination of water bodies through the leakage of nitrate, salt and agrochemicals. A large fraction of world agricultural activities and therefore NPS contamination occurs over unconsolidated alluvial deposit basins offering soil composition and topography favorable to productive farming. These basins represent also important groundwater reservoirs. The over-exploitation of aquifers coupled with groundwater pollution by agriculture-related NPS contaminant has led to a rapid deterioration of the quality of these groundwater basins. The management of groundwater contamination from NPS is challenged by the inherent complexity of aquifers systems. Contaminant transport dynamics are highly uncertain due to the heterogeneity of hydraulic parameters controlling groundwater flow. Well characteristics are also key uncertain elements affecting pollutant transport and NPS management but quantifying uncertainty in NPS management under these conditions is not well documented. Our work focuses on better understanding the joint impact of aquifer heterogeneity and pumping well characteristics (extraction rate and depth) on (1) the transport of contaminants from NPS and (2) the spatio-temporal extension of the capture zone. To do so, we generate a series of geostatistically equivalent 3D heterogeneous aquifers and simulate the flow and non-reactive solute transport from NPS to extraction wells within a stochastic framework. The propagation of the uncertainty on the hydraulic conductivity field is systematically analyzed. A sensitivity analysis of the impact of extraction well characteristics (pumping rate and screen depth) is also conducted. Results highlight the significant role that heterogeneity and well characteristics plays on management metrics. We finally show that, in case of NPS contamination, the joint impact of regional longitudinal and transverse vertical hydraulic gradients and well depth strongly constrain the average travel times and extension of the contributing area.

Contamination, Transport, and Exposure Mapping and Assessment of Karst Groundwater Systems in Northern Puerto Rico Using GIS

NASA Astrophysics Data System (ADS)

Howard, J.; Schifman, L. A.; Irrizary, C.; Torres, P.; Padilla, I. Y.

2011-12-01

Ground waters from karst aquifer systems are one of the most important sources of freshwater worldwide and are highly vulnerable to both natural and anthropogenic contamination. Contaminants released into karst groundwater systems move through complex pathways from their sources to discharge areas of potential exposure. Points of exposure can include wells, springs, and surface waters that serve as drinking water sources. In Puerto Rico, the North Coast Limestone Aquifer System, which extends 90 miles across the north coast with an area of nearly 700 sq. miles, provides more than 50% of the potable water demand for industrial and drinking purposes. Historical reports from the 1980s revealed that volatile organic compounds, phthalates, and metals were close to or exceeded maximum contaminant levels. Exposure to such contaminants has been reported to cause reproductive and developmental issues, such as preterm birth. Since there is minimal understanding of the extent of contamination it is important to identify areas of potential concern. Preliminary analysis of 20 groundwater/springs and 20 tap water sites within the North Coast suggest that contamination is still a major concern. In addition, mixed effects models analyses suggest that >60% of pre-term birth rates may be explained by the presence of sites contaminated with volatile organic compounds, phthalates, and metals within the North Coast region. This presentation will focus primarily on how GIS was used as a tool for developing sampling strategies for collecting groundwater and tap water sources within the North Coast Limestone Aquifer System of Puerto Rico. In addition, the linkage of contamination, transport, and exposure to volatile organic compounds and phthalates will be addressed.

Contaminant point source localization error estimates as functions of data quantity and model quality

DOE PAGES

Hansen, Scott K.; Vesselinov, Velimir Valentinov

2016-10-01

We develop empirically-grounded error envelopes for localization of a point contamination release event in the saturated zone of a previously uncharacterized heterogeneous aquifer into which a number of plume-intercepting wells have been drilled. We assume that flow direction in the aquifer is known exactly and velocity is known to within a factor of two of our best guess from well observations prior to source identification. Other aquifer and source parameters must be estimated by interpretation of well breakthrough data via the advection-dispersion equation. We employ high performance computing to generate numerous random realizations of aquifer parameters and well locations, simulatemore » well breakthrough data, and then employ unsupervised machine optimization techniques to estimate the most likely spatial (or space-time) location of the source. Tabulating the accuracy of these estimates from the multiple realizations, we relate the size of 90% and 95% confidence envelopes to the data quantity (number of wells) and model quality (fidelity of ADE interpretation model to actual concentrations in a heterogeneous aquifer with channelized flow). We find that for purely spatial localization of the contaminant source, increased data quantities can make up for reduced model quality. For space-time localization, we find similar qualitative behavior, but significantly degraded spatial localization reliability and less improvement from extra data collection. Since the space-time source localization problem is much more challenging, we also tried a multiple-initial-guess optimization strategy. Furthermore, this greatly enhanced performance, but gains from additional data collection remained limited.« less

Characterization of mercury contamination in the Androscoggin River, Coos County, New Hampshire

USGS Publications Warehouse

Chalmers, Ann; Marvin-DiPasquale, Mark C.; Degnan, James R.; Coles, James; Agee, Jennifer L.; Luce, Darryl

2013-01-01

Concentrations of total mercury (THg) and MeHg in sediment, pore water, and biota in the Androscoggin River were elevated downstream from the former chloralkali facility compared with those upstream from reference sites. Sequential extraction of surface sediment showed a distinct difference in Hg speciation upstream compared with downstream from the contamination site. An upstream site was dominated by potassium hydroxide-extractable forms (for example, organic-Hg or particle-bound Hg(II)), whereas sites downstream from the point source were dominated by more chemically recalcitrant forms (largely concentrated nitric acid-extractable), indicative of elemental mercury or mercurous chloride. At all sites, only a minor fraction (less than 0.1 percent) of THg existed in chemically labile forms (for example, water extractable or weak acid extractable). All metrics indicated that a greater percentage of mercury at an upstream site was available for Hg(II)-methylation compared with sites downstream from the point source, but the absolute concentration of bioavailable Hg(II) was greater downstream from the point source. In addition, the concentration of tin-reducible inorganic reactive mercury, a surrogate measure of bioavailable Hg(II) generally increased with distance downstream from the point source. Whereas concentrations of mercury species on a sediment-dry-weight basis generally reflected the relative location of the sample to the point source, river-reach integrated mercury-species inventories and MeHg production potential (MPP) rates reflected the amount of fine-grained sediment in a given reach. THg concentrations in biota were significantly higher downstream from the point source compared with upstream reference sites for smallmouth bass, white sucker, crayfish, oligochaetes, bat fur, nestling tree swallow blood and feathers, adult tree swallow blood, and tree swallow eggs. As with tin-reducible inorganic reactive mercury, THg in smallmouth bass also increased with distance downstream from the point source. Toxicity tests and invertebrate community assessments suggested that invertebrates were not impaired at the current (2009 and 2010) levels of mercury contamination downstream from the point source. Concentrations of THg and MeHg in most water and sediment samples from the Androscoggin River were below U.S. Environmental Protection Agency (USEPA), the Canadian Council of Ministers of the Environment, and probable effects level guidelines. Surface-water and sediment samples from the Androscoggin River had similar THg concentrations but lower MeHg concentrations compared with other rivers in the region. Concentrations of THg in fish tissue were all above regional and U.S. Environmental Protection Agency guidelines. Moreover, median THg concentrations in smallmouth bass from the Androscoggin River were significantly higher than those reported in regional surveys of river and streams nationwide and in the Northeastern United States and Canada. The higher concentrations of mercury in smallmouth bass suggest conditions may be more favorable for Hg(II)-methylation and bioaccumulation in the Androscoggin River compared with many other rivers in the United States and Canada.

Particle transport in low-energy ventilation systems. Part 2: Transients and experiments.

PubMed

Bolster, D T; Linden, P F

2009-04-01

Providing adequate indoor air quality while reducing energy consumption is a must for efficient ventilation system design. In this work, we study the transport of particulate contaminants in a displacement-ventilated space, using the idealized 'emptying filling box' model (P.F. Linden, G.F. Lane-serff and D.A. Smeed (1990) Emptying filling boxes: the fluid mechanics of natural ventilation, J. fluid Mech., 212, 309-335.). In this paper, we focused on transient contaminant transport by modeling three transient contamination scenarios, namely the so called 'step-up', 'step-down', and point source cases. Using analytical integral models and numerical models we studied the transient behavior of each of these three cases. We found that, on average, traditional and low-energy systems can be similar in overall pollutant removal efficiency, although quite different vertical gradients can exist. This plays an important role in estimating occupant exposure to contaminant. A series of laboratory experiments were conducted to validate the developed models. The results presented here illustrate that the source location plays a very important role in the distribution of contaminant concentration for spaces ventilated by low energy displacement-ventilation systems. With these results and the knowledge of typical contaminant sources for a given type of space practitioners can design or select more effective systems for the purpose at hand.

Chemical quality of tap water in Madrid: multicase control cancer study in Spain (MCC-Spain).

PubMed

Fernández-Navarro, Pablo; Villanueva, Cristina M; García-Pérez, Javier; Boldo, Elena; Goñi-Irigoyen, Fernando; Ulibarrena, Enrique; Rantakokko, Panu; García-Esquinas, Esther; Pérez-Gómez, Beatriz; Pollán, Marina; Aragonés, Nuria

2017-02-01

Chronic consumption of water, which contains contaminants, may give rise to adverse health effects. The Madrid region, covered by the population-based multicase-control (MCC-Spain) study, includes two drinking water supply areas. The different sources of the water, coupled together with the possible differences in water management, mean that there may be differences in drinking water quality. In the context of the MCC study, our aims were to describe contaminant concentrations in tap water drawn from various sampling points distributed around the region, assess these concentrations by reference to guideline values and study possible differences between the two supply areas. Tap water samples were collected from 34 sampling points in 7 towns in the Madrid region (19-29 April 2010), and 23 contaminants (metals, nitrates, disinfection by-product and Mutagen X levels) were quantified. We undertook a descriptive analysis of the contaminant concentrations in the water and compared them between the two water supply areas (Wilcoxon test). We created maps representing the distribution of the concentrations observed at water sampling points and assessed the correlations (Spearman's coefficient) between the different parameters measured. The concentrations of the contaminants were below guideline values. There were differences between the two supply areas in concentration of nitrates (p value = 0.0051) and certain disinfection by-products. While there were positive correlations (rho >0.70) among some disinfection by-products, no correlations were found in metals or nitrates. The differences in nitrate levels could be linked to differences in farming/industrial activities in the catchment areas and in disinfection by-products might be related to the existence of different treatment systems or bromine content in source waters.

Characterization and Remediation of Chlorinated Volatile Organic Contaminants in the Vadose Zone: An Overview of Issues and Approaches

PubMed Central

Brusseau, Mark L.; Carroll, Kenneth C.; Truex, Michael J.; Becker, David J.

2014-01-01

Contamination of vadose-zone systems by chlorinated solvents is widespread, and poses significant potential risk to human health through impacts on groundwater quality and vapor intrusion. Soil vapor extraction (SVE) is the presumptive remedy for such contamination, and has been used successfully for innumerable sites. However, SVE operations typically exhibit reduced mass-removal effectiveness at some point due to the impact of poorly accessible contaminant mass and associated mass-transfer limitations. Assessment of SVE performance and closure is currently based on characterizing contaminant mass discharge associated with the vadose-zone source, and its impact on groundwater or vapor intrusion. These issues are addressed in this overview, with a focus on summarizing recent advances in our understanding of the transport, characterization, and remediation of chlorinated solvents in the vadose zone. The evolution of contaminant distribution over time and the associated impacts on remediation efficiency will be discussed, as will the potential impact of persistent sources on groundwater quality and vapor intrusion. In addition, alternative methods for site characterization and remediation will be addressed. PMID:25383058

Arsenic, microbes and contaminated aquifers

USGS Publications Warehouse

Oremland, Ronald S.; Stolz, John F.

2005-01-01

The health of tens of millions of people world-wide is at risk from drinking arsenic-contaminated well water. In most cases this arsenic occurs naturally within the sub-surface aquifers, rather than being derived from identifiable point sources of pollution. The mobilization of arsenic into the aqueous phase is the first crucial step in a process that eventually leads to human arsenicosis. Increasing evidence suggests that this is a microbiological phenomenon.

Chemical contamination and physical characteristics of sediments in the upper Great Lakes connecting channels 1985

USGS Publications Warehouse

Bertram, Paul E.; Edsall, Thomas A.; Manny, Bruce A.; Nichols, Susan J.; Schloesser, Donald W.

1991-01-01

Contamination of sediments by toxic organic substances and heavy metals was widespread throughout the connecting channels of the upper Great Lakes in 1985. Sediments at 250 stations in the connecting channels were analyzed for total PCBs, oil and grease, phenols, total cyanide, total volatile solids, mercury, cadmium, chromium, cobalt, copper, lead, nickel, and zinc, and the results were evaluated according to U.S. EPA guidelines for polluted sediments. Sediments were most heavily contaminated near industrialized areas, although some areas more than 40 km downstream from known point sources of pollution were moderately contaminated by oil and metals.

Fowl play? Forensic environmental assessment of alleged discharge of highly contaminated effluent from a chicken slaughterhouse

NASA Astrophysics Data System (ADS)

Harvey, P.; Taylor, M. P.; Handley, H. K.

2016-12-01

Multiple lines of geochemical and biological evidence are applied to identify and fingerprint the nature and source of alleged contamination emanating from a chicken slaughterhouse on the urban fringe of Sydney, Australia. The slaughterhouse has a long history of alleged environmental misconduct. The impact of the facility on catchment source waters by the slaughterhouse has been the subject of controversy. The facility owner has persistently denied breach of their licence condition and maintains it is `a very environmentally conscious operation'. The disputed nature of the possible sources of discharges and its contaminants required a detailed forensic environmental assessment. Water samples collected from off-site discharge points associated with the facility show highly elevated concentrations of faecal coliforms (max 68,000 cfu), ammonia-N (51,000 µg/L), total nitrogen (98,000 µg/L) and phosphorous (32,000 µg/L). Upstream and adjacent watercourses were markedly less contaminated. Water discharge points associated with the slaughterhouse and natural catchment runoff were sampled for arsenic speciation, including assessment for the organoarsenic compound Roxarsone. Roxarsone is used as a chicken growth promoter. Water draining the slaughterhouse facility contained concentrations around 10 times local background levels. The Roxarsone compound was not detected in any waters, but inorganic arsenic, As(V), was present in all waters with the greatest concentrations in waters draining from the slaughterhouse. The environmental evidence was compiled over a series of discharges events and presented to the NSW EPA. Subsequent to receipt of the data supported by their own investigations, the NSW EPA mandated that the slaughterhouse be subject to a pollution reduction program. The efficacy of the pollution reduction program to stem the release of highly contaminated effluent is currently subject to ongoing investigation using a suite of water chemistry measures including DNA analysis.

Comparison of Microbial and Chemical Source Tracking Markers To Identify Fecal Contamination Sources in the Humber River (Toronto, Ontario, Canada) and Associated Storm Water Outfalls.

PubMed

Staley, Zachery R; Grabuski, Josey; Sverko, Ed; Edge, Thomas A

2016-11-01

Storm water runoff is a major source of pollution, and understanding the components of storm water discharge is essential to remediation efforts and proper assessment of risks to human and ecosystem health. In this study, culturable Escherichia coli and ampicillin-resistant E. coli levels were quantified and microbial source tracking (MST) markers (including markers for general Bacteroidales spp., human, ruminant/cow, gull, and dog) were detected in storm water outfalls and sites along the Humber River in Toronto, Ontario, Canada, and enumerated via endpoint PCR and quantitative PCR (qPCR). Additionally, chemical source tracking (CST) markers specific for human wastewater (caffeine, carbamazepine, codeine, cotinine, acetaminophen, and acesulfame) were quantified. Human and gull fecal sources were detected at all sites, although concentrations of the human fecal marker were higher, particularly in outfalls (mean outfall concentrations of 4.22 log 10 copies, expressed as copy numbers [CN]/100 milliliters for human and 0.46 log 10 CN/100 milliliters for gull). Higher concentrations of caffeine, acetaminophen, acesulfame, E. coli, and the human fecal marker were indicative of greater raw sewage contamination at several sites (maximum concentrations of 34,800 ng/liter, 5,120 ng/liter, 9,720 ng/liter, 5.26 log 10 CFU/100 ml, and 7.65 log 10 CN/100 ml, respectively). These results indicate pervasive sewage contamination at storm water outfalls and throughout the Humber River, with multiple lines of evidence identifying Black Creek and two storm water outfalls with prominent sewage cross-connection problems requiring remediation. Limited data are available on specific sources of pollution in storm water, though our results indicate the value of using both MST and CST methodologies to more reliably assess sewage contamination in impacted watersheds. Storm water runoff is one of the most prominent non-point sources of biological and chemical contaminants which can potentially degrade water quality and pose risks to human and ecosystem health. Therefore, identifying fecal contamination in storm water runoff and outfalls is essential for remediation efforts to reduce risks to public health. This study employed multiple methods of identifying levels and sources of fecal contamination in both river and storm water outfall sites, evaluating the efficacy of using culture-based enumeration of E. coli, molecular methods of determining the source(s) of contamination, and CST markers as indicators of fecal contamination. The results identified pervasive human sewage contamination in storm water outfalls and throughout an urban watershed and highlight the utility of using both MST and CST to identify raw sewage contamination. © Crown copyright 2016.

Comparison of Microbial and Chemical Source Tracking Markers To Identify Fecal Contamination Sources in the Humber River (Toronto, Ontario, Canada) and Associated Storm Water Outfalls

PubMed Central

Grabuski, Josey; Sverko, Ed; Edge, Thomas A.

2016-01-01

ABSTRACT Storm water runoff is a major source of pollution, and understanding the components of storm water discharge is essential to remediation efforts and proper assessment of risks to human and ecosystem health. In this study, culturable Escherichia coli and ampicillin-resistant E. coli levels were quantified and microbial source tracking (MST) markers (including markers for general Bacteroidales spp., human, ruminant/cow, gull, and dog) were detected in storm water outfalls and sites along the Humber River in Toronto, Ontario, Canada, and enumerated via endpoint PCR and quantitative PCR (qPCR). Additionally, chemical source tracking (CST) markers specific for human wastewater (caffeine, carbamazepine, codeine, cotinine, acetaminophen, and acesulfame) were quantified. Human and gull fecal sources were detected at all sites, although concentrations of the human fecal marker were higher, particularly in outfalls (mean outfall concentrations of 4.22 log10 copies, expressed as copy numbers [CN]/100 milliliters for human and 0.46 log10 CN/100 milliliters for gull). Higher concentrations of caffeine, acetaminophen, acesulfame, E. coli, and the human fecal marker were indicative of greater raw sewage contamination at several sites (maximum concentrations of 34,800 ng/liter, 5,120 ng/liter, 9,720 ng/liter, 5.26 log10 CFU/100 ml, and 7.65 log10 CN/100 ml, respectively). These results indicate pervasive sewage contamination at storm water outfalls and throughout the Humber River, with multiple lines of evidence identifying Black Creek and two storm water outfalls with prominent sewage cross-connection problems requiring remediation. Limited data are available on specific sources of pollution in storm water, though our results indicate the value of using both MST and CST methodologies to more reliably assess sewage contamination in impacted watersheds. IMPORTANCE Storm water runoff is one of the most prominent non-point sources of biological and chemical contaminants which can potentially degrade water quality and pose risks to human and ecosystem health. Therefore, identifying fecal contamination in storm water runoff and outfalls is essential for remediation efforts to reduce risks to public health. This study employed multiple methods of identifying levels and sources of fecal contamination in both river and storm water outfall sites, evaluating the efficacy of using culture-based enumeration of E. coli, molecular methods of determining the source(s) of contamination, and CST markers as indicators of fecal contamination. The results identified pervasive human sewage contamination in storm water outfalls and throughout an urban watershed and highlight the utility of using both MST and CST to identify raw sewage contamination. PMID:27542934

Contaminant transport from point source on water surface in open channel flow with bed absorption

NASA Astrophysics Data System (ADS)

Guo, Jinlan; Wu, Xudong; Jiang, Weiquan; Chen, Guoqian

2018-06-01

Studying solute dispersion in channel flows is of significance for environmental and industrial applications. Two-dimensional concentration distribution for a most typical case of a point source release on the free water surface in a channel flow with bed absorption is presented by means of Chatwin's long-time asymptotic technique. Five basic characteristics of Taylor dispersion and vertical mean concentration distribution with skewness and kurtosis modifications are also analyzed. The results reveal that bed absorption affects both the longitudinal and vertical concentration distributions and causes the contaminant cloud to concentrate in the upper layer. Additionally, the cross-sectional concentration distribution shows an asymptotic Gaussian distribution at large time which is unaffected by the bed absorption. The vertical concentration distribution is found to be nonuniform even at large time. The obtained results are essential for practical implements with strict environmental standards.

Household Effectiveness vs. Laboratory Efficacy of Point-of-use Chlorination

PubMed Central

Levy, Karen; Anderson, Larissa; Robb, Katharine A.; Cevallos, William; Trueba, Gabriel; Eisenberg, Joseph N.S.

2014-01-01

Treatment of water at the household level offers a promising approach to combat the global burden of diarrheal diseases. In particular, chlorination of drinking water has been a widely promoted strategy due to persistence of residual chlorine after initial treatment. However, the degree to which chlorination can reduce microbial levels in a controlled setting (efficacy) or in a household setting (effectiveness) can vary as a function of chlorine characteristics, source water characteristics, and household conditions. To gain more understanding of these factors, we carried out an observational study within households in rural communities of northern coastal Ecuador. We found that the efficacy of chlorine treatment under controlled conditions was significantly better than its effectiveness when evaluated both by ability to meet microbiological safety standards and by log reductions. Water treated with chlorine achieved levels of microbial contamination considered safe for human consumption after 24 hours of storage in the household only 39 – 51% of the time, depending on chlorine treatment regimen. Chlorine treatment would not be considered protective against diarrheal disease according to WHO log reduction standards. Factors that explain the observed compromised effectiveness include: source water turbidity, source water baseline contamination levels, and in-home contamination. Water in 38% of the households that had low turbidity source water (< 10 NTU) met the safe water standard as compared with only 17% of the households that had high turbidity source water (> 10 NTU). A 10 MPN/100mL increase in baseline E. coli levels was associated with a 2.2% increase in failure to meet the E. colistandard. Higher mean microbial contamination levels in 54% of household samples in comparison to their matched controls, which is likely the result of in-home contamination during storage. Container characteristics (size of the container mouth) did not influence chlorine effectiveness. We found no significant differences between chlorine treatment regimens in ability to meet the safe water standards or in overall log reductions, although chlorine dosage did modify the effect of source conditions. These results underscore the importance of measuring both source water and household conditions to determine appropriate chlorine levels, as well as to evaluate the appropriateness of chlorine treatment and other point-of-use water quality improvement interventions. PMID:24561887

Household effectiveness vs. laboratory efficacy of point-of-use chlorination.

PubMed

Levy, Karen; Anderson, Larissa; Robb, Katharine A; Cevallos, William; Trueba, Gabriel; Eisenberg, Joseph N S

2014-05-01

Treatment of water at the household level offers a promising approach to combat the global burden of diarrheal diseases. In particular, chlorination of drinking water has been a widely promoted strategy due to persistence of residual chlorine after initial treatment. However, the degree to which chlorination can reduce microbial levels in a controlled setting (efficacy) or in a household setting (effectiveness) can vary as a function of chlorine characteristics, source water characteristics, and household conditions. To gain more understanding of these factors, we carried out an observational study within households in rural communities of northern coastal Ecuador. We found that the efficacy of chlorine treatment under controlled conditions was significantly better than its household effectiveness when evaluated both by ability to meet microbiological safety standards and by log reductions. Water treated with chlorine achieved levels of microbial contamination considered safe for human consumption after 24 h of storage in the household only 39-51% of the time, depending on chlorine treatment regimen. Chlorine treatment would not be considered protective against diarrheal disease according to WHO log reduction standards. Factors that explain the observed compromised effectiveness include: source water turbidity, source water baseline contamination levels, and in-home contamination. Water in 38% of the households that had low turbidity source water (<10 NTU) met the safe water standard as compared with only 17% of the households that had high turbidity source water (>10 NTU). A 10 MPN/100 mL increase in baseline Escherichia coli levels was associated with a 2.2% increase in failure to meet the E. coli standard. Higher mean microbial contamination levels were seen in 54% of household samples in comparison to their matched controls, which is likely the result of in-home contamination during storage. Container characteristics (size of the container mouth) did not influence chlorine effectiveness. We found no significant differences between chlorine treatment regimens in ability to meet the safe water standards or in overall log reductions, although chlorine dosage did modify the effect of source conditions. These results underscore the importance of measuring both source water and household conditions to determine appropriate chlorine levels, as well as to evaluate the appropriateness of chlorine treatment and other point-of-use water quality improvement interventions. Copyright © 2014 Elsevier Ltd. All rights reserved.

A method for separation of heavy metal sources in urban groundwater using multiple lines of evidence.

PubMed

Hepburn, Emily; Northway, Anne; Bekele, Dawit; Liu, Gang-Jun; Currell, Matthew

2018-06-11

Determining sources of heavy metals in soils, sediments and groundwater is important for understanding their fate and transport and mitigating human and environmental exposures. Artificially imported fill, natural sediments and groundwater from 240 ha of reclaimed land at Fishermans Bend in Australia, were analysed for heavy metals and other parameters to determine the relative contributions from different possible sources. Fishermans Bend is Australia's largest urban re-development project, however, complicated land-use history, geology, and multiple contamination sources pose challenges to successful re-development. We developed a method for heavy metal source separation in groundwater using statistical categorisation of the data, analysis of soil leaching values and fill/sediment XRF profiling. The method identified two major sources of heavy metals in groundwater: 1. Point sources from local or up-gradient groundwater contaminated by industrial activities and/or legacy landfills; and 2. contaminated fill, where leaching of Cu, Mn, Pb and Zn was observed. Across the precinct, metals were most commonly sourced from a combination of these sources; however, eight locations indicated at least one metal sourced solely from fill leaching, and 23 locations indicated at least one metal sourced solely from impacted groundwater. Concentrations of heavy metals in groundwater ranged from 0.0001 to 0.003 mg/L (Cd), 0.001-0.1 mg/L (Cr), 0.001-0.2 mg/L (Cu), 0.001-0.5 mg/L (Ni), 0.001-0.01 mg/L (Pb), and 0.005-1.2 mg/L (Zn). Our method can determine the likely contribution of different metal sources to groundwater, helping inform more detailed contamination assessments and precinct-wide management and remediation strategies. Copyright © 2018 Elsevier Ltd. All rights reserved.

Prevalence of household drinking-water contamination and of acute diarrhoeal illness in a periurban community in Myanmar.

PubMed

Myint, Su Latt Tun; Myint, Thuzar; Aung, Wah Wah; Wai, Khin Thet

2015-01-01

A major health consequence of rapid population growth in urban areas is the increased pressure on existing overstretched water and sanitation services. This study of an expanding periurban neighbourhood of Yangon Region, Myanmar, aimed to ascertain the prevalence of acute diarrhoea in children under 5 years; to identify household sources of drinking-water; to describe purification and storage practices; and to assess drinking-water contamination at point-of-use. A survey of the prevalence of acute diarrhoea in children under 5 years was done in 211 households in February 2013; demographic data were also collected, along with data and details of sources of drinking water, water purification, storage practices and waste disposal. During March-August, a subset of 112 households was revisited to collect drinking water samples. The samples were analysed by the multiple tube fermentation method to count thermotolerant (faecal) coliforms and there was a qualitative determination of the presence of Escherichia coli. Acute diarrhoea in children under 5 years was reported in 4.74% (10/211, 95% CI: 3.0-9.0) of households within the past two weeks. More than half of the households used insanitary pit latrines and 36% disposed of their waste into nearby streams and ponds. Improved sources of drinking water were used, mainly the unchlorinated ward reservoir, a chlorinated tube well or purified bottled water. Nearly a quarter of households never used any method for drinking-water purification. Ninety-four per cent (105/112) of water samples were contaminated with thermotolerant (faecal) coliforms, ranging from 2.2 colony-forming units (CFU)/100 mL (21.4%) to more than 1000 CFU/100 mL (60.7%). Of faecal (thermotolerant)-coliform-positive water samples, 70% (47/68) grew E. coli. The prevalence of acute diarrhoea reported for children under 5 years was high and a high level of drinking-water contamination was detected, though it was unclear whether this was due to contamination at source or at point-of-use. Maintenance of drinking-water quality in study households is complex. Further research is crucial to prove the cost effectiveness in quality improvement of drinking water at point-of-use in resource-limited settings. In addition, empowerment of householders to use measures of treating water by boiling, filtration or chlorination, and safe storage with proper handling is essential.

Control Points To Reduce Movement of Central Nervous System Tissue during Beef Slaughter.

PubMed

Aalhus, J L; Thacker, R D; Larsen, I L; Roberts, J C; Price, M A; Juárez, M

2017-02-01

Consumption of central nervous system tissue (CNST) from cattle with bovine spongiform encephalopathy (BSE) is thought to cause the human neurological disease, variant Creutzfeldt-Jacob disease. To identify points of cross-contamination of beef carcasses with CNST, 55 young beef cattle were slaughtered and processed through a federally inspected multispecies abattoir. The objectives of this study were to evaluate CNST spread following the placement of a plug in the penetration site of the skull after captive bolt stunning, to evaluate cross-contamination of carcasses before and after splitting, to compare the effects of hot water pasteurization (84°C for 10 s) versus cold water wash (10°C for 30 s) for reducing CNST on the carcass, and to examine other possible sources of cross-contamination in the abattoir. Results indicated that the use of a plastic plug reduced CNST contamination near the bolt penetration site. This study also confirmed that carcass splitting resulted in an increase in CNST contamination at various areas of the carcass. Hot water pasteurization appeared to be an effective means of removing CNST contamination from carcasses in most of the areas sampled.

Characterization and simulation of fate and transport of selected volatile organic compounds in the vicinities of the Hadnot Point Industrial Area and landfill: Chapter A Supplement 6 in Analyses and historical reconstruction of groundwater flow, contaminant fate and transport, and distribution of drinking water within the service areas of the Hadnot Point and Holcomb Boulevard Water Treatment Plants and vicinities, U.S. Marine Corps Base Camp Lejeune, North Carolina

USGS Publications Warehouse

Jones, L. Elliott; Suárez-Soto, René J.; Anderson, Barbara A.; Maslia, Morris L.

2013-01-01

This supplement of Chapter A (Supplement 6) describes the reconstruction (i.e. simulation) of historical concentrations of tetrachloroethylene (PCE), trichloroethylene (TCE), and benzene3 in production wells supplying water to the Hadnot Base (USMCB) Camp Lejeune, North Carolina (Figure S6.1). A fate and transport model (i.e., MT3DMS [Zheng and Wang 1999]) was used to simulate contaminant migration from source locations through the groundwater system and to estimate mean contaminant concentrations in water withdrawn from water-supply wells in the vicinity of the Hadnot Point Industrial Area (HPIA) and the Hadnot Point landfill (HPLF) area.4 The reconstructed contaminant concentrations were subsequently input into a flow-weighted, materials mass balance (mixing) model (Masters 1998) to estimate monthly mean concentrations of the contaminant in finished water 5 at the HPWTP (Maslia et al. 2013). The calibrated fate and transport models described herein were based on and used groundwater velocities derived from groundwater-flow models that are described in Suárez-Soto et al. (2013). Information data pertinent to historical operations of water-supply wells are described in Sautner et al. (2013) and Telci et al. (2013).

Methods Used to Assess the Susceptibility to Contamination of Transient, Non-Community Public Ground-Water Supplies in Indiana

USGS Publications Warehouse

Arihood, Leslie D.; Cohen, David A.

2006-01-01

The Safe Water Drinking Act of 1974 as amended in 1996 gave each State the responsibility of developing a Source-Water Assessment Plan (SWAP) that is designed to protect public-water supplies from contamination. Each SWAP must include three elements: (1) a delineation of the source-water protection area, (2) an inventory of potential sources of contaminants within the area, and (3) a determination of the susceptibility of the public-water supply to contamination from the inventoried sources. The Indiana Department of Environmental Management (IDEM) was responsible for preparing a SWAP for all public-water supplies in Indiana, including about 2,400 small public ground-water supplies that are designated transient, non-community (TNC) supplies. In cooperation with IDEM, the U.S. Geological Survey compiled information on conditions near the TNC supplies and helped IDEM complete source-water assessments for each TNC supply. The delineation of a source-water protection area (called the assessment area) for each TNC ground-water supply was defined by IDEM as a circular area enclosed by a 300-foot radius centered at the TNC supply well. Contaminants of concern (COCs) were defined by IDEM as any of the 90 contaminants for which the U.S. Environmental Protection Agency has established primary drinking-water standards. Two of these, nitrate as nitrogen and total coliform bacteria, are Indiana State-regulated contaminants for TNC water supplies. IDEM representatives identified potential point and nonpoint sources of COCs within the assessment area, and computer database retrievals were used to identify potential point sources of COCs in the area outside the assessment area. Two types of methods-subjective and subjective hybrid-were used in the SWAP to determine susceptibility to contamination. Subjective methods involve decisions based upon professional judgment, prior experience, and (or) the application of a fundamental understanding of processes without the collection and analysis of data for a specific condition. Subjective hybrid methods combine subjective methods with quantitative hydrologic analyses. The subjective methods included an inventory of potential sources and associated contaminants, and a qualitative description of the inherent susceptibility of the area around the TNC supply. The description relies on a classification of the hydrogeologic and geomorphic characteristics of the general area around the TNC supply in terms of its surficial geology, regional aquifer system, the occurrence of fine- and coarse-grained geologic materials above the screen of the TNC well, and the potential for infiltration of contaminants. The subjective hybrid method combined the results of a logistic regression analysis with a subjective analysis of susceptibility and a subjective set of definitions that classify the thickness of fine-grained geologic materials above the screen of a TNC well in terms of impedance to vertical flow. The logistic regression determined the probability of elevated concentrations of nitrate as nitrogen (greater than or equal to 3 milligrams per liter) in ground water associated with specific thicknesses of fine-grained geologic materials above the screen of a TNC well. In this report, fine-grained geologic materials are referred to as a geologic barrier that generally impedes vertical flow through an aquifer. A geologic barrier was defined to be thin for fine-grained materials between 0 and 45 feet thick, moderate for materials between 45 and 75 feet thick, and thick if the fine-grained materials were greater than 75 feet thick. A flow chart was used to determine the susceptibility rating for each TNC supply. The flow chart indicated a susceptibility rating using (1) concentrations of nitrate as nitrogen and total coliform bacteria reported from routine compliance monitoring of the TNC supply, (2) the presence or absence of potential sources of regulated contaminants (nitrate as nitrogen and coliform bac

The impact of land use on microbial surface water pollution.

PubMed

Schreiber, Christiane; Rechenburg, Andrea; Rind, Esther; Kistemann, Thomas

2015-03-01

Our knowledge relating to water contamination from point and diffuse sources has increased in recent years and there have been many studies undertaken focusing on effluent from sewage plants or combined sewer overflows. However, there is still only a limited amount of microbial data on non-point sources leading to diffuse pollution of surface waters. In this study, the concentrations of several indicator micro-organisms and pathogens in the upper reaches of a river system were examined over a period of 16 months. In addition to bacteria, diffuse pollution caused by Giardia lamblia and Cryptosporidium spp. was analysed. A single land use type predestined to cause high concentrations of all microbial parameters could not be identified. The influence of different land use types varies between microbial species. The microbial concentration in river water cannot be explained by stable non-point effluent concentrations from different land use types. There is variation in the ranking of the potential of different land use types resulting in surface water contamination with regard to minimum, median and maximum effects. These differences between median and maximum impact indicate that small-scale events like spreading manure substantially influence the general contamination potential of a land use type and may cause increasing micro-organism concentrations in the river water by mobilisation during the next rainfall event. Copyright © 2014 Elsevier GmbH. All rights reserved.

COSMIC MICROWAVE BACKGROUND POLARIZATION AND TEMPERATURE POWER SPECTRA ESTIMATION USING LINEAR COMBINATION OF WMAP 5 YEAR MAPS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Samal, Pramoda Kumar; Jain, Pankaj; Saha, Rajib

We estimate cosmic microwave background (CMB) polarization and temperature power spectra using Wilkinson Microwave Anisotropy Probe (WMAP) 5 year foreground contaminated maps. The power spectrum is estimated by using a model-independent method, which does not utilize directly the diffuse foreground templates nor the detector noise model. The method essentially consists of two steps: (1) removal of diffuse foregrounds contamination by making linear combination of individual maps in harmonic space and (2) cross-correlation of foreground cleaned maps to minimize detector noise bias. For the temperature power spectrum we also estimate and subtract residual unresolved point source contamination in the cross-power spectrummore » using the point source model provided by the WMAP science team. Our TT, TE, and EE power spectra are in good agreement with the published results of the WMAP science team. We perform detailed numerical simulations to test for bias in our procedure. We find that the bias is small in almost all cases. A negative bias at low l in TT power spectrum has been pointed out in an earlier publication. We find that the bias-corrected quadrupole power (l(l + 1)C{sub l} /2{pi}) is 532 {mu}K{sup 2}, approximately 2.5 times the estimate (213.4 {mu}K{sup 2}) made by the WMAP team.« less

The Effectiveness of Sanitary Inspections as a Risk Assessment Tool for Thermotolerant Coliform Bacteria Contamination of Rural Drinking Water: A Review of Data from West Bengal, India

PubMed Central

Snoad, Christian; Nagel, Corey; Bhattacharya, Animesh; Thomas, Evan

2017-01-01

The use of sanitary inspections combined with periodic water quality testing has been recommended in some cases as screening tools for fecal contamination. We conducted sanitary inspections and tested for thermotolerant coliforms (TTCs), a fecal indicator bacteria, among 7,317 unique water sources in West Bengal, India. Our results indicate that the sanitary inspection score has poor ability to identify TTC-contaminated sources. Among deep and shallow hand pumps, the area under curve (AUC) for prediction of TTC > 0 was 0.58 (95% confidence interval [CI] = 0.53–0.61) and 0.58 (95% CI = 0.54–0.62), respectively, indicating that the sanitary inspection score was only marginally better than chance in discriminating between contaminated and uncontaminated sources of this type. A slightly higher AUC value of 0.64 (95% CI=0.57–0.71) was observed when the sanitary inspection score was used for prediction of TTC > 0 among the gravity-fed piped sources. Among unprotected springs (AUC = 0.48, 95% CI = 0.38–0.55) and unprotected dug wells (AUC = 0.41, 95% CI = 0.20–0.66), the sanitary inspection score performed more poorly than chance in discriminating between sites with TTC < 1 and TTC > 0. Aggregating over all source types, the sensitivity (true positive rate) of a high/very high sanitary inspection score for TTC contamination (TTC > 1 CFU/100 mL) was 29.4% and the specificity (true negative rate) was 77.9%, resulting in substantial misclassification of the sites when using the established risk categories. These findings suggest that sanitary surveys are inappropriate screening tools for identifying TTC contamination at water points. PMID:28115676

The Effectiveness of Sanitary Inspections as a Risk Assessment Tool for Thermotolerant Coliform Bacteria Contamination of Rural Drinking Water: A Review of Data from West Bengal, India.

PubMed

Snoad, Christian; Nagel, Corey; Bhattacharya, Animesh; Thomas, Evan

2017-04-01

AbstractThe use of sanitary inspections combined with periodic water quality testing has been recommended in some cases as screening tools for fecal contamination. We conducted sanitary inspections and tested for thermotolerant coliforms (TTCs), a fecal indicator bacteria, among 7,317 unique water sources in West Bengal, India. Our results indicate that the sanitary inspection score has poor ability to identify TTC-contaminated sources. Among deep and shallow hand pumps, the area under curve (AUC) for prediction of TTC > 0 was 0.58 (95% confidence interval [CI] = 0.53-0.61) and 0.58 (95% CI = 0.54-0.62), respectively, indicating that the sanitary inspection score was only marginally better than chance in discriminating between contaminated and uncontaminated sources of this type. A slightly higher AUC value of 0.64 (95% CI=0.57-0.71) was observed when the sanitary inspection score was used for prediction of TTC > 0 among the gravity-fed piped sources. Among unprotected springs (AUC = 0.48, 95% CI = 0.38-0.55) and unprotected dug wells (AUC = 0.41, 95% CI = 0.20-0.66), the sanitary inspection score performed more poorly than chance in discriminating between sites with TTC < 1 and TTC > 0. Aggregating over all source types, the sensitivity (true positive rate) of a high/very high sanitary inspection score for TTC contamination (TTC > 1 CFU/100 mL) was 29.4% and the specificity (true negative rate) was 77.9%, resulting in substantial misclassification of the sites when using the established risk categories. These findings suggest that sanitary surveys are inappropriate screening tools for identifying TTC contamination at water points.

Chiral perturbation theory and nucleon-pion-state contaminations in lattice QCD

NASA Astrophysics Data System (ADS)

Bär, Oliver

2017-05-01

Multiparticle states with additional pions are expected to be a non-negligible source of excited-state contamination in lattice simulations at the physical point. It is shown that baryon chiral perturbation theory can be employed to calculate the contamination due to two-particle nucleon-pion-states in various nucleon observables. Leading order results are presented for the nucleon axial, tensor and scalar charge and three Mellin moments of parton distribution functions (quark momentum fraction, helicity and transversity moment). Taking into account phenomenological results for the charges and moments the impact of the nucleon-pion-states on lattice estimates for these observables can be estimated. The nucleon-pion-state contribution results in an overestimation of all charges and moments obtained with the plateau method. The overestimation is at the 5-10% level for source-sink separations of about 2 fm. The source-sink separations accessible in contemporary lattice simulations are found to be too small for chiral perturbation theory to be directly applicable.

A conceptual ground-water-quality monitoring network for San Fernando Valley, California

USGS Publications Warehouse

Setmire, J.G.

1985-01-01

A conceptual groundwater-quality monitoring network was developed for San Fernando Valley to provide the California State Water Resources Control Board with an integrated, basinwide control system to monitor the quality of groundwater. The geology, occurrence and movement of groundwater, land use, background water quality, and potential sources of pollution were described and then considered in designing the conceptual monitoring network. The network was designed to monitor major known and potential point and nonpoint sources of groundwater contamination over time. The network is composed of 291 sites where wells are needed to define the groundwater quality. The ideal network includes four specific-purpose networks to monitor (1) ambient water quality, (2) nonpoint sources of pollution, (3) point sources of pollution, and (4) line sources of pollution. (USGS)

Clean Room Apparel

NASA Technical Reports Server (NTRS)

1989-01-01

American Hospital Supply Corporation (AHSC), Baxter Healthcare Corporation's predecessor, used the NASA informational base on contamination control technology to improve industrial contamination control technology. When a study determined that microscopic body particles escaping through tiny "windows" in woven garments worn by workers were the greatest source of contamination, AHSC developed TYVEK. This non-woven material filters 99% of all particulate matter larger than half a micron. Baxter Healthcare added a polyimide coating which seals and ties down any loose fibers, providing greater durability. Stress points along seams have been minimized to make the garment almost tearproof. Micro-Clean 212 garments are individually packaged and disposable.

Endocrine active contaminants in aquatic systems and intersex in common sport fishes

USGS Publications Warehouse

Lee Pow, Crystal S. D.; Law, J. Mac; Kwak, Thomas J.; Cope, W. Gregory; Rice, James A.; Kullman, Seth W.; Aday, D. Derek

2017-01-01

Male fish are susceptible to developing intersex, a condition characterized by the presence of testicular oocytes. In the present study, the relationship between intersex and exposure to estrogenic endocrine active contaminants (EACs) was assessed for 2 genera of sport fish, Micropterus and Lepomis, at 20 riverine sites. Seasonal trends and relationships between EACs and intersex (prevalence and severity) were examined at varying putative sources of EACs throughout North Carolina, identified as point sources, nonpoint sources, and reference sites. Intersex was identified in both genera, which was documented for the first time in wild-caught Lepomis. Intersex was more prevalent (59.8%) and more severe (1.6 mean rank) in Micropterus, which was highly correlation to EACs in sediment. In contrast, intersex was less common (9.9%) and less severe (0.2 mean rank) in Lepomis and was highly correlated to EACs in the water column. The authors found that concentrations of polycyclic aromatic hydrocarbons, polychlorinated biphenyls, industrial EACs, and estrogens were highest at point source sites; however, no source type variation was identified in the prevalence or severity of intersex, nor were there seasonal trends in intersex or EAC concentrations. The authors’ results associate genus-specific prevalence of intersex with specific EAC classes in common sport fishes having biological, ecological, and conservation implications.

Alkylphenolic compounds and bisphenol A contamination within a heavily urbanized area: case study of Paris.

PubMed

Cladière, Mathieu; Gasperi, Johnny; Lorgeoux, Catherine; Bonhomme, Céline; Rocher, Vincent; Tassin, Bruno

2013-05-01

This study evaluates the influence of a heavily urbanized area (Paris Metropolitan area), on receiving water contamination by both bisphenol A (BPA) and alkylphenol ethoxylate (APE) biodegradation product. The study began by investigating concentrations within urban sources. In addition to the more commonly studied wastewater treatment plant effluent, wet weather urban sources (including combined sewer overflows, urban runoff, and total atmospheric fallout) were considered. The initial results highlight a significant contamination of all urban sources (from a few nanograms per liter in atmospheric fallout to several micrograms per liter in the other sources) with clearly distinguishable distribution patterns. Secondly, concentration changes along the Seine River from upstream of the Paris Metropolitan area to downstream were investigated. While the concentrations of BPA and nonylphenoxy acetic acid (NP₁EC) increase substantially due to urban sources, the 4-nonylphenol concentrations remain homogeneous along the Seine. These results suggest a broad dissemination of 4-nonylphenol at the scale of the Seine River basin. Moreover, the relationship between pollutant concentrations and Seine River flow was assessed both upstream and downstream of the Paris conurbation. Consequently, a sharp decrease in dissolved NP1EC concentrations relative to Seine River flow underscores the influence of single-point urban pollution on Seine River contamination. Conversely, dissolved 4-nonylphenol concentrations serve to reinforce the hypothesis of its widespread presence at the Seine River basin scale.

TSCA Environmental Release Application (TERA) for Modified Escherichia coli

EPA Pesticide Factsheets

TERA submitted by University of North Carolina and given tracking designation of R-01-0001. The microorganism will be introduced into potential sources of fecal contamination to determine if the bacteria can be detected downstream from the release points.

High (36)Cl/Cl ratios in Chernobyl groundwater.

PubMed

Roux, Céline; Le Gal La Salle, Corinne; Simonucci, Caroline; Van Meir, Nathalie; Fifield, L Keith; Diez, Olivier; Bassot, Sylvain; Simler, Roland; Bugai, Dmitri; Kashparov, Valery; Lancelot, Joël

2014-12-01

After the explosion of the Chernobyl Nuclear Power Plant in April 1986, contaminated material was buried in shallow trenches within the exclusion zone. A (90)Sr plume was evidenced downgradient of one of these trenches, trench T22. Due to its conservative properties, (36)Cl is investigated here as a potential tracer to determine the maximal extent of the contamination plume from the trench in groundwater. (36)Cl/Cl ratios measured in groundwater, trench soil water and leaf leachates are 1-5 orders of magnitude higher than the theoretical natural (36)Cl/Cl ratio. This contamination occurred after the Chernobyl explosion and currently persists. Trench T22 acts as an obvious modern point source of (36)Cl, however other sources have to be involved to explain such contamination. (36)Cl contamination of groundwater can be explained by dilution of trench soil water by uncontaminated water (rainwater or deep groundwater). With a plume extending further than that of (90)Sr, radionuclide which is impacted by retention and decay processes, (36)Cl can be considered as a suitable tracer of contamination from the trench in groundwater provided that modern release processes of (36)Cl from trench soil are better characterized. Copyright © 2014 Elsevier Ltd. All rights reserved.

Experimental study of gaseous and particulate contaminants distribution in an aircraft cabin

NASA Astrophysics Data System (ADS)

Li, Fei; Liu, Junjie; Pei, Jingjing; Lin, Chao-Hsin; Chen, Qingyan

2014-03-01

The environment of the aircraft cabin greatly influences the comfort and health of passengers and crew members. Contaminant transport has a strong effect on disease spreading in the cabin environment. To obtain the complex cabin contaminant distribution fields accurately and completely, which is also essential to provide solid and precise data for computational fluid dynamics (CFD) model validation, this paper aimed to investigate and improve the method for simultaneous particle and gaseous contaminant fields measurement. The experiment was conducted in a functional MD-82 aircraft. Sulfur hexafluoride (SF6) was used as tracer gas, and Di-Ethyl-Hexyl-Sebacat (DEHS) was used as particulate contaminant. The whole measurement was completed in a part of the economy-class cabin without heating manikins or occupied with heating manikins. The experimental method, in terms of pollutant source setting, sampling points and schedule, was investigated. Statistical analysis showed that appropriately modified sampling grid was able to provide reasonable data. A small difference in the source locations can lead to a significant difference in cabin contaminant fields. And the relationship between gaseous and particulate pollutant transport was also discussed through tracking behavior analysis.

Historic and contemporary contamination in the marine environment of Kuwait: An overview.

PubMed

Al-Sarawi, Hanan A; Jha, Awadhesh N; Al-Sarawi, Mohammad A; Lyons, Brett P

2015-11-30

The rapid expansion of industry, along with previous pollution events linked to conflicts in the region, have led to a variety of contaminants being inadvertently or deliberately discharged into Kuwait's marine environment. These include polycyclic aromatic hydrocarbons (PAHs) and trace metals, from the petrochemical industry, and contaminated brine from the region's desalination industries. The present paper has reviewed over 60 studies that have reported the levels of contaminants, including PAHs, metals and polychlorinated biphenyls (PCBs) present in seawater, sediment and representative marine organisms. Most of the reviewed literature confirmed that while Kuwait's marine environment has been subjected to a wide array of pollution events, the actual levels of contamination remains relatively low. However, sediment contamination hotspots associated with point sources of industrial contamination, such as originating from the Shuaiba industrial area, do exist at a number of locations around the coast. Copyright © 2015 Elsevier Ltd. All rights reserved.

Dissemination of drinking water contamination data to consumers: a systematic review of impact on consumer behaviors.

PubMed

Lucas, Patricia J; Cabral, Christie; Colford, John M

2011-01-01

Drinking water contaminated by chemicals or pathogens is a major public health threat in the developing world. Responses to this threat often require water consumers (households or communities) to improve their own management or treatment of water. One approach hypothesized to increase such positive behaviors is increasing knowledge of the risks of unsafe water through the dissemination of water contamination data. This paper reviews the evidence for this approach in changing behavior and subsequent health outcomes. A systematic review was conducted for studies where results of tests for contaminants in drinking water were disseminated to populations whose water supply posed a known health risk. Studies of any design were included where data were available from a contemporaneous comparison or control group. Using multiple sources >14,000 documents were located. Six studies met inclusion criteria (four of arsenic contamination and two of microbiological contamination). Meta-analysis was not possible in most cases due to heterogeneity of outcomes and study designs. Outcomes included water quality, change of water source, treatment of water, knowledge of contamination, and urinary arsenic. Source switching was most frequently reported: of 5 reporting studies 4 report significantly higher rates of switching (26-72%) among those who received a positive test result and a pooled risk difference was calculate for 2 studies (RD = 0.43 [CI0.4.0-0.46] 6-12 months post intervention) suggesting 43% more of those with unsafe wells switched source compared to those with safe wells. Strength of evidence is low since the comparison is between non-equivalent groups. Two studies concerning fecal contamination reported non-significant increases in point-of-use water treatment. Despite the publication of some large cohort studies and some encouraging results the evidence base to support dissemination of contamination data to improve water management is currently equivocal. Rigorous studies on this topic are needed, ideally using common outcome measures.

Dissemination of Drinking Water Contamination Data to Consumers: A Systematic Review of Impact on Consumer Behaviors

PubMed Central

Lucas, Patricia J.; Cabral, Christie; Colford, John M.

2011-01-01

Background Drinking water contaminated by chemicals or pathogens is a major public health threat in the developing world. Responses to this threat often require water consumers (households or communities) to improve their own management or treatment of water. One approach hypothesized to increase such positive behaviors is increasing knowledge of the risks of unsafe water through the dissemination of water contamination data. This paper reviews the evidence for this approach in changing behavior and subsequent health outcomes. Methods/Principal Findings A systematic review was conducted for studies where results of tests for contaminants in drinking water were disseminated to populations whose water supply posed a known health risk. Studies of any design were included where data were available from a contemporaneous comparison or control group. Using multiple sources >14,000 documents were located. Six studies met inclusion criteria (four of arsenic contamination and two of microbiological contamination). Meta-analysis was not possible in most cases due to heterogeneity of outcomes and study designs. Outcomes included water quality, change of water source, treatment of water, knowledge of contamination, and urinary arsenic. Source switching was most frequently reported: of 5 reporting studies 4 report significantly higher rates of switching (26–72%) among those who received a positive test result and a pooled risk difference was calculate for 2 studies (RD = 0.43 [CI0.4.0–0.46] 6–12 months post intervention) suggesting 43% more of those with unsafe wells switched source compared to those with safe wells. Strength of evidence is low since the comparison is between non-equivalent groups. Two studies concerning fecal contamination reported non-significant increases in point-of-use water treatment. Conclusion Despite the publication of some large cohort studies and some encouraging results the evidence base to support dissemination of contamination data to improve water management is currently equivocal. Rigorous studies on this topic are needed, ideally using common outcome measures. PMID:21738609

Evidence for Legacy Contamination of Nitrate in Groundwater of North Carolina Using Monitoring and Private Well Data Models

NASA Astrophysics Data System (ADS)

Messier, K. P.; Kane, E.; Bolich, R.; Serre, M. L.

2014-12-01

Nitrate (NO3-) is a widespread contaminant of groundwater and surface water across the United States that has deleterious effects to human and ecological health. Legacy contamination, or past releases of NO3-, is thought to be impacting current groundwater and surface water of North Carolina. This study develops a model for predicting point-level groundwater NO3- at a state scale for monitoring wells and private wells of North Carolina. A land use regression (LUR) model selection procedure known as constrained forward nonlinear regression and hyperparameter optimization (CFN-RHO) is developed for determining nonlinear model explanatory variables when they are known to be correlated. Bayesian Maximum Entropy (BME) is then used to integrate the LUR model to create a LUR-BME model of spatial/temporal varying groundwater NO3- concentrations. LUR-BME results in a leave-one-out cross-validation r2 of 0.74 and 0.33 for monitoring and private wells, effectively predicting within spatial covariance ranges. The major finding regarding legacy sources NO3- in this study is that the LUR-BME models show the geographical extent of low-level contamination of deeper drinking-water aquifers is beyond that of the shallower monitoring well. Groundwater NO3- in monitoring wells is highly variable with many areas predicted above the current Environmental Protection Agency standard of 10 mg/L. Contrarily, the private well results depict widespread, low-level NO3-concentrations. This evidence supports that in addition to downward transport, there is also a significant outward transport of groundwater NO3- in the drinking water aquifer to areas outside the range of sources. Results indicate that the deeper aquifers are potentially acting as a reservoir that is not only deeper, but also covers a larger geographical area, than the reservoir formed by the shallow aquifers. Results are of interest to agencies that regulate surface water and drinking water sources impacted by the effects of legacy NO3- sources. Additionally, the results can provide guidance on factors affecting the point-level variability of groundwater NO3- and areas where monitoring is needed to reduce uncertainty. Lastly, LUR-BME predictions can be integrated into surface water models for more accurate management of non-point sources of nitrogen.

Zinc speciation in proximity to phosphate application points in a lead/zinc smelter-contaminated soil.

PubMed

Baker, Lucas R; Pierzynski, Gary M; Hettiarachchi, Ganga M; Scheckel, Kirk G; Newville, Matthew

2012-01-01

The use of P to immobilize Pb in contaminated soils has been well documented. However, the influence of P on Zn speciation in soils has not been extensively examined, and these two metals often occur as co-contaminants. We hypothesized that additions of P to a Pb/Zn-contaminated soil would induce Zn phosphate mineral formation and fluid P sources would be more effective than granular P amendments. A combination of different synchrotron-based techniques, namely, spatially resolved micro-X-ray fluorescence (μ-XRF), micro-extended X-ray absorption fine structure spectroscopy (μ-EXAFS), and micro-X-ray diffraction (μ-XRD), were used to speciate Zn at two incubation times in the proximity of application points (0 to 4 mm) for fluid and granular P amendments in a Pb/Zn smelter-contaminated soil. Phosphate rock (PR), triple super phosphate (TSP), monoammonium phosphate (MAP), and fluid ammonium polyphosphate induced Zn phosphate formation. Ammonium polyphosphate was more effective at greater distances (up to 3.7 mm) from the point of P application. Phosphoric acid increased the presence of soluble Zn species because of increased acidity. Soluble Zn has implications with respect to Zn bioavailability, which may negatively impact vegetation and other sensitive organisms. Although additions of P immobilize Pb, this practice needs close monitoring due to potential increases in Zn solubility in a Pb/Zn smelter-contaminated soil. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

FRNA Bacteriophages as Viral Indicators of Faecal Contamination in Mexican Tropical Aquatic Systems.

PubMed

Arredondo-Hernandez, Luis Jose Rene; Diaz-Avalos, Carlos; Lopez-Vidal, Yolanda; Castillo-Rojas, Gonzalo; Mazari-Hiriart, Marisa

2017-01-01

A particular challenge to water safety in populous intertropical regions is the lack of reliable faecal indicators to detect microbiological contamination of water, while the numerical relationships of specific viral indicators remain largely unexplored. The aim of this study was to investigate the numerical relationships of FRNA-bacteriophage genotypes, adenovirus 41, and human adenoviruses (HADV) in Mexican surface water systems to assess sewage contamination. We studied the presence of HADV, HADV41 and FRNA bacteriophage genotypes in water samples and quantified by qPCR and RT-qPCR. Virus and water quality indicator variances, as analyzed by principal component analysis and partial least squared regression, followed along the major percentiles of water faecal enterococci. FRNA bacteriophages adequately deciphered viral and point source water contamination. The strongest correlation for HADV was with FRNA bacteriophage type II, in water samples higher than the 50th percentiles of faecal enterococci, thus indicating urban pollution. FRNA bacteriophage genotypes I and III virus indicator performances were assisted by their associations with electrical conductivity and faecal enterococci. In combination, our methods are useful for inferring water quality degradation caused by sewage contamination. The methods used have potential for determining source contamination in water and, specifically, the presence of enteric viruses where clean and contaminated water have mixed.

FRNA Bacteriophages as Viral Indicators of Faecal Contamination in Mexican Tropical Aquatic Systems

PubMed Central

Diaz-Avalos, Carlos; Lopez-Vidal, Yolanda; Castillo-Rojas, Gonzalo; Mazari-Hiriart, Marisa

2017-01-01

A particular challenge to water safety in populous intertropical regions is the lack of reliable faecal indicators to detect microbiological contamination of water, while the numerical relationships of specific viral indicators remain largely unexplored. The aim of this study was to investigate the numerical relationships of FRNA-bacteriophage genotypes, adenovirus 41, and human adenoviruses (HADV) in Mexican surface water systems to assess sewage contamination. We studied the presence of HADV, HADV41 and FRNA bacteriophage genotypes in water samples and quantified by qPCR and RT-qPCR. Virus and water quality indicator variances, as analyzed by principal component analysis and partial least squared regression, followed along the major percentiles of water faecal enterococci. FRNA bacteriophages adequately deciphered viral and point source water contamination. The strongest correlation for HADV was with FRNA bacteriophage type II, in water samples higher than the 50th percentiles of faecal enterococci, thus indicating urban pollution. FRNA bacteriophage genotypes I and III virus indicator performances were assisted by their associations with electrical conductivity and faecal enterococci. In combination, our methods are useful for inferring water quality degradation caused by sewage contamination. The methods used have potential for determining source contamination in water and, specifically, the presence of enteric viruses where clean and contaminated water have mixed. PMID:28114378

Livestock ownership and microbial contamination of drinking-water: Evidence from nationally representative household surveys in Ghana, Nepal and Bangladesh.

PubMed

Wardrop, Nicola A; Hill, Allan G; Dzodzomenyo, Mawuli; Aryeetey, Genevieve; Wright, Jim A

2018-01-01

Current priorities for diarrhoeal disease prevention include use of sanitation and safe water. There have been few attempts to quantify the importance of animal faeces in drinking-water contamination, despite the presence of potentially water-borne zoonotic pathogens in animal faeces. This study aimed to quantify the relationship between livestock ownership and point-of-consumption drinking-water contamination. Data from nationally representative household surveys in Nepal, Bangladesh, and Ghana, each with associated water quality assessments, were used. Multinomial regression adjusting for confounders was applied to assess the relationship between livestock ownership and the level of drinking-water contamination with E. coli. Ownership of five or more large livestock (e.g. cattle) was significantly associated with drinking-water contamination in Ghana (RRR=7.9, 95% CI=1.6 to 38.9 for medium levels of contamination with 1-31cfu/100ml; RRR=5.2, 95% CI=1.1-24.5 for high levels of contamination with >31cfu/100ml) and Bangladesh (RRR=2.4, 95% CI=1.3-4.5 for medium levels of contamination; non-significant for high levels of contamination). Ownership of eight or more poultry (chickens, guinea fowl, ducks or turkeys) was associated with drinking-water contamination in Bangladesh (RRR=1.5, 95% CI=1.1-2.0 for medium levels of contamination, non-significant for high levels of contamination). These results suggest that livestock ownership is a significant risk factor for the contamination of drinking-water at the point of consumption. This indicates that addressing human sanitation without consideration of faecal contamination from livestock sources will not be sufficient to prevent drinking-water contamination. Copyright © 2017 The Authors. Published by Elsevier GmbH.. All rights reserved.

Nitrate in aquifers beneath agricultural systems

USGS Publications Warehouse

Burkart, M.R.; Stoner, J.D.; ,

2007-01-01

Research from several regions of the world provides spatially anecdotal evidence to hypothesize which hydrologic and agricultural factors contribute to groundwater vulnerability to nitrate contamination. Analysis of nationally consistent measurements from the U.S. Geological Survey's NAWQA program confirms these hypotheses for a substantial range of agricultural systems. Shallow unconfined aquifers are most susceptible to nitrate contamination associated with agricultural systems. Alluvial and other unconsolidated aquifers are the most vulnerable and also shallow carbonate aquifers that provide a substantial but smaller contamination risk. Where any of these aquifers are overlain by permeable soils the risk of contamination is larger. Irrigated systems can compound this vulnerability by increasing leaching facilitated by additional recharge and additional nutrient applications. The system of corn, soybean, and hogs produced significantly larger concentrations of groundwater nitrate than all other agricultural systems because this system imports the largest amount of N-fertilizer per unit production area. Mean nitrate under dairy, poultry, horticulture, and cattle and grains systems were similar. If trends in the relation between increased fertilizer use and groundwater nitrate in the United States are repeated in other regions of the world, Asia may experience increasing problems because of recent increases in fertilizer use. Groundwater monitoring in Western and Eastern Europe as well as Russia over the next decade may provide data to determine if the trend in increased nitrate contamination can be reversed. If the concentrated livestock trend in the United States is global, it may be accompanied by increasing nitrogen contamination in groundwater. Concentrated livestock provide both point sources in the confinement area and intense non-point sources as fields close to facilities are used for manure disposal. Regions where irrigated cropland is expanding, such as in Asia, may experience the greatest impact of this practice on groundwater nitrate. ?? USDA 2007.

Nitrate in aquifers beneath agricultural systems

USGS Publications Warehouse

Burkart, M.R.; Stoner, J.D.

2002-01-01

Research from several regions of the world provides spatially anecdotal evidence to hypothesize which hydrologic and agricultural factors contribute to groundwater vulnerability to nitrate contamination. Analysis of nationally consistent measurements from the U.S. Geological Survey's NAWOA program confirms these hypotheses for a substantial range of agricultural systems. Shallow unconfined aquifers are most susceptible to nitrate contamination associated with agricultural systems. Alluvial and other unconsolidated aquifers are the most vulnerable and shallow carbonate aquifers provide a substantial but smaller contamination risk. Where any of these aquifers are overlain by permeable soils the risk of contamination is larger. Irrigated systems can compound this vulnerability by increasing leaching facilitated by additional recharge and additional nutrient applications. The agricultural system of corn, soybeans, and hogs produced significantly larger concentrations of groundwater nitrate than all other agricultural systems, although mean nitrate concentrations in counties with dairy, poultry, cattle and grains, and horticulture systems were similar. If trends in the relation between increased fertilizer use and groundwater nitrate in the United States are repeated in other regions of the world, Asia may experience increasing problems because of recent increases in fertilizer use. Groundwater monitoring in Western and Eastern Europe as well as Russia over the next decade may provide data to determine if the trend in increased nitrate contamination can be reversed. If the concentrated livestock trend in the United States is global, it may be accompanied by increasing nitrogen contamination in groundwater. Concentrated livestock provide both point sources in the confinement area and intense non-point sources as fields close to facilities are used for manure disposal. Regions where irrigated cropland is expanding, such as in Asia, may experience the greatest impact of this practice.

Water quality in organic systems

USDA-ARS?s Scientific Manuscript database

Non-point source contamination is a major water quality concern in the upper Midwestern USA, where plant nutrients, especially NO3-N, are susceptible to leaching due to extensive subsurface draining of the highly productive, but poorly drained, soils found in this region. Environmental impacts assoc...

STREAM CORRIDOR RESTORATION AND ITS POTENTIAL TO IMPROVE WATER QUALITY

EPA Science Inventory

Watershed stream corridors are being degraded by anthropogenic impacts of increased flow from runoff, sediment loading from erosion and contaminants such as nitrate from non-point sources. One solution is to restore stream corridors with bank stabilization and energy dissipation ...

A WORKABLE DEFINITION OF SUCCESS

EPA Science Inventory

The most desirable definition of success from the point of view of environmental stewardship is to treat the entire plume to MCLs. Technically, has proven impossible to attain at many sites. A less desirable definition of success is to contain the source of contamination and tr...

Water quality modeling using geographic information system (GIS) data

NASA Technical Reports Server (NTRS)

Engel, Bernard A

1992-01-01

Protection of the environment and natural resources at the Kennedy Space Center (KSC) is of great concern. The potential for surface and ground water quality problems resulting from non-point sources of pollution was examined using models. Since spatial variation of parameters required was important, geographic information systems (GIS) and their data were used. The potential for groundwater contamination was examined using the SEEPAGE (System for Early Evaluation of the Pollution Potential of Agricultural Groundwater Environments) model. A watershed near the VAB was selected to examine potential for surface water pollution and erosion using the AGNPS (Agricultural Non-Point Source Pollution) model.

Using dynamic flux chambers to estimate the natural attenuation rates in the subsurface at petroleum contaminated sites.

PubMed

Verginelli, Iason; Pecoraro, Roberto; Baciocchi, Renato

2018-04-01

In this work, we introduce a screening method for the evaluation of the natural attenuation rates in the subsurface at sites contaminated by petroleum hydrocarbons. The method is based on the combination of the data obtained from standard source characterization with dynamic flux chambers measurements. The natural attenuation rates are calculated as difference between the flux of contaminants estimated with a non-reactive diffusive model starting from the concentrations of the contaminants detected in the source (soil and/or groundwater) and the effective emission rate of the contaminants measured using dynamic flux chambers installed at ground level. The reliability of this approach was tested in a contaminated site characterized by the presence of BTEX in soil and groundwater. Namely, the BTEX emission rates from the subsurface were measured in 4 seasonal campaigns using dynamic flux chambers installed in 14 sampling points. The comparison of measured fluxes with those predicted using a non-reactive diffusive model, starting from the source concentrations, showed that, in line with other recent studies, the modelling approach can overestimate the expected outdoor concentration of petroleum hydrocarbons even up to 4 orders of magnitude. On the other hand, by coupling the measured data with the fluxes estimated with the diffusive non-reactive model, it was possible to perform a mass balance to evaluate the natural attenuation loss rates of petroleum hydrocarbons during the migration from the source to ground level. Based on this comparison, the estimated BTEX loss rates in the test site were up to almost 0.5kg/year/m 2 . These rates are in line with the values reported in the recent literature for natural source zone depletion. In short, the method presented in this work can represent an easy-to-use and cost-effective option that can provide a further line of evidence of natural attenuation rates expected at contaminated sites. Copyright © 2017 Elsevier B.V. All rights reserved.

Using artificial sweeteners to identify contamination sources and infiltration zones in a coupled river-aquifer system

NASA Astrophysics Data System (ADS)

Bichler, Andrea; Muellegger, Christian; Hofmann, Thilo

2014-05-01

In shallow or unconfined aquifers the infiltration of contaminated river water might be a major threat to groundwater quality. Thus, the identification of possible contamination sources in coupled surface- and groundwater systems is of paramount importance to ensure water quality. Micropollutants like artificial sweeteners are promising markers for domestic waste water in natural water bodies. Compounds, such as artificial sweeteners, might enter the aquatic environment via discharge of waste water treatment plants, leaky sewer systems or septic tanks and are ubiquitously found in waste water receiving waters. The hereby presented field study aims at the (1) identification of contamination sources and (2) delineation of infiltration zones in a connected river-aquifer system. River bank filtrate in the groundwater body was assessed qualitatively and quantitatively using a combined approach of hydrochemical analysis and artificial sweeteners (acesulfame ACE) as waste water markers. The investigated aquifer lies within a mesoscale alpine head water catchment and is used for drinking water production. It is hypothesized that a large proportion of the groundwater flux originates from bank filtrate of a nearby losing stream. Water sampling campaigns in March and July 2012 confirmed the occurrence of artificial sweeteners at the investigated site. The municipal waste water treatment plant was identified as point-source for ACE in the river network. In the aquifer ACE was present in more than 80% of the monitoring wells. In addition, water samples were classified according to their hydrochemical composition, identifying two predominant types of water in the aquifer: (1) groundwater influenced by bank filtrate and (2) groundwater originating from local recharge. In combination with ACE concentrations a third type of water could be discriminated: (3) groundwater influence by bank filtrate but infiltrated prior to the waste water treatment plant. Moreover, the presence of ACE at elevated concentrations in aquifer zones dominated by local recharge indicated another point-source of domestic waste water. The combined analysis of ACE and conventional hydrochemical data proved to be useful to identify different sources of waste water. It is shown that the combination of physicochemical parameters and artificial sweeteners allow for a clear delineation of infiltration areas in the investigated aquifer system.

Decreasing aqueous mercury concentrations to achieve safe levels in fish: examining the water-fish relationship in two point-source contaminated streams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mathews, Teresa J; Southworth, George R; Peterson, Mark J

2013-01-01

East Fork Poplar Creek (EFPC) and White Oak Creek (WOC) are two mercury-contaminated streams located on the Department of Energy s Oak Ridge Reservation in east Tennessee. East Fork Poplar Creek is the larger and more contaminated of the two, with average aqueous mercury (Hg) concentrations exceeding those in reference streams by several hundred-fold. Remedial actions over the past 20 years have decreased aqueous Hg concentrations in EFPC by 85 %. Fish fillet concentrations, however, have not responded to this decrease in aqueous Hg and remain above the U.S. Environmental Protection Agency s ambient water quality criterion (AWQC) of 0.3more » mg/kg. The lack of correlation between aqueous and fish tissue Hg concentrations in this creek has led to questions regarding the usefulness of target aqueous Hg concentrations and strategies for future remediation efforts. White Oak Creek has a similar contamination history but aqueous Hg concentrations in WOC are an order of magnitude lower than in EFPC. Despite the lower aqueous Hg concentrations, fish fillet concentrations in WOC have also been above the AWQC, making the most recent aqueous Hg target of 200 ng/L in EFPC seem unlikely to result in an effective decrease in fillet Hg concentrations. Recent monitoring efforts in WOC, however, suggest an aqueous total Hg threshold above which Hg bioaccumulation in fish may not respond. This new information could be useful in guiding remedial actions in EFPC and in other point-source contaminated streams.« less

Successful application of lead isotopes in source apportionment, legal proceedings, remediation and monitoring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gulson, Brian, E-mail: brian.gulson@mq.edu.au; CSIRO Earth Science and Resource Engineering North Ryde, NSW 1670; Korsch, Michael

In late 2006, the seaside community in Esperance Western Australia was alerted to thousands of native bird species dying. The source of the lead (Pb) was determined by Pb isotopes to derive from the handling of Pb carbonate concentrate through the Port, which began in July 2005. Concern was expressed for the impact of this on the community. Our objectives were to employ Pb isotope ratios to evaluate the source of Pb in environmental samples for use in legal proceedings, and for use in remediation and monitoring. Isotope measurements were undertaken of bird livers, plants, drinking water, soil, harbour sediments,more » air, bulk ceiling dust, gutter sludge, surface swabs and blood. The unique lead isotopic signature of the contaminating Pb carbonate enabled diagnostic apportionment of lead in samples. Apart from some soil and water samples, the proportion of contaminating Pb was >95% in the environmental samples. Lead isotopes were critical in resolving legal proceedings, are being used in the remediation of premises, were used in monitoring of workers involved in the decontamination of the storage facility, and monitoring transport of the concentrate through another port facility. Air samples show the continued presence of contaminant Pb, more than one year after shipping of concentrate ceased, probably arising from dust resuspension. Brief details of the comprehensive testing and cleanup of the Esperance community are provided along with the role of the Community. Lead isotopic analyses can provide significant benefits to regulatory agencies, interested parties, and the community where the signature is able to be characterised with a high degree of certainty. - Highlights: Black-Right-Pointing-Triangle Lead carbonate concentrate. Black-Right-Pointing-Triangle Successful use of Pb isotopes in identifying sources of Pb arising from transport and shipping. Black-Right-Pointing-Triangle Use of Pb isotopes in legal proceedings and their use in cleanup of residences. Black-Right-Pointing-Triangle Use of Pb isotopes in cleanup of a residual 9000 tonnes of Pb carbonate and in ongoing monitoring.« less

Does groundwater protection in Europe require new EU-wide environmental quality standards?

PubMed

Balderacchi, Matteo; Filippini, Maria; Gemitzi, Alexandra; Klöve, Björn; Petitta, Marco; Trevisan, Marco; Wachniew, Przemysław; Witczak, Stanisław; Gargini, Alessandro

2014-01-01

The European Groundwater Directive could be improved by limiting the scopes of the Annexes I and II to the manmade and natural substances, respectively, and by defining a common monitoring protocol. The changes in the European landuse patterns, in particular the urban sprawl phenomena, obscure the distinction between the point and diffuse sources of contamination. In the future more importance will be given to the household contamination. Moreover, the agricultural environment could be used for developing new conceptual models related to the pharmaceuticals.

Impacts by point and diffuse micropollutant sources on the stream water quality at catchment scale

NASA Astrophysics Data System (ADS)

Petersen, M. F.; Eriksson, E.; Binning, P. J.; Bjerg, P. L.

2012-04-01

The water quality of surface waters is threatened by multiple anthropogenic pollutants and the large variety of pollutants challenges the monitoring and assessment of the water quality. The aim of this study was to characterize and quantify both point and diffuse sources of micropollutants impacting the water quality of a stream at catchment scale. Grindsted stream in western Jutland, Denmark was used as a study site. The stream passes both urban and agricultural areas and is impacted by severe groundwater contamination in Grindsted city. Along a 12 km reach of Grindsted stream, the potential pollution sources were identified including a pharmaceutical factory site with a contaminated old drainage ditch, two waste deposits, a wastewater treatment plant, overflow structures, fish farms, industrial discharges and diffuse agricultural and urban sources. Six water samples were collected along the stream and analyzed for general water quality parameters, inorganic constituents, pesticides, sulfonamides, chlorinated solvents, BTEXs, and paracetamol and ibuprofen. The latter two groups were not detected. The general water quality showed typical conditions for a stream in western Jutland. Minor impacts by releases of organic matter and nutrients were found after the fish farms and the waste water treatment plant. Nickel was found at concentrations 5.8 - 8.8 μg/l. Nine pesticides and metabolites of both agricultural and urban use were detected along the stream; among these were the two most frequently detected and some rarely detected pesticides in Danish water courses. The concentrations were generally consistent with other findings in Danish streams and in the range 0.01 - 0.09 μg/l; except for metribuzin-diketo that showed high concentrations up to 0.74 μg/l. The groundwater contamination at the pharmaceutical factory site, the drainage ditch and the waste deposits is similar in composition containing among others sulfonamides and chlorinated solvents (including vinyl chloride). Vinyl chloride concentrations surpassed Danish stream water quality criteria with a factor 10. The largest chemical impact occurs at the reach downstream Grindsted city revealing that the main contaminant groundwater discharge zones are found here. The contaminant plume from the factory site north of the stream is known to impact the stream whereas the impact by the old landfill south of the stream remains to be assessed. A conceptual model of the chemical impacts by the identified sources was made, and high impact was assigned to the contaminant plume from the factory site and to the diffuse sources of urban-use and agricultural pesticides. The next step will be a quantification of the sources, which will be presented at the conference.

Assessment of ambient background concentrations of elements in soil using combined survey and open-source data.

PubMed

Mikkonen, Hannah G; Clarke, Bradley O; Dasika, Raghava; Wallis, Christian J; Reichman, Suzie M

2017-02-15

Understanding ambient background concentrations in soil, at a local scale, is an essential part of environmental risk assessment. Where high resolution geochemical soil surveys have not been undertaken, soil data from alternative sources, such as environmental site assessment reports, can be used to support an understanding of ambient background conditions. Concentrations of metals/metalloids (As, Mn, Ni, Pb and Zn) were extracted from open-source environmental site assessment reports, for soils derived from the Newer Volcanics basalt, of Melbourne, Victoria, Australia. A manual screening method was applied to remove samples that were indicated to be contaminated by point sources and hence not representative of ambient background conditions. The manual screening approach was validated by comparison to data from a targeted background soil survey. Statistical methods for exclusion of contaminated samples from background soil datasets were compared to the manual screening method. The statistical methods tested included the Median plus Two Median Absolute Deviations, the upper whisker of a normal and log transformed Tukey boxplot, the point of inflection on a cumulative frequency plot and the 95th percentile. We have demonstrated that where anomalous sample results cannot be screened using site information, the Median plus Two Median Absolute Deviations is a conservative method for derivation of ambient background upper concentration limits (i.e. expected maximums). The upper whisker of a boxplot and the point of inflection on a cumulative frequency plot, were also considered adequate methods for deriving ambient background upper concentration limits, where the percentage of contaminated samples is <25%. Median ambient background concentrations of metals/metalloids in the Newer Volcanic soils of Melbourne were comparable to ambient background concentrations in Europe and the United States, except for Ni, which was naturally enriched in the basalt-derived soils of Melbourne. Copyright © 2016 Elsevier B.V. All rights reserved.

The Sources of Chemical Contaminants in Food and Their Health Implications

PubMed Central

Rather, Irfan A.; Koh, Wee Yin; Paek, Woon K.; Lim, Jeongheui

2017-01-01

Food contamination is a matter of serious concern, as the high concentration of chemicals present in the edibles poses serious health risks. Protecting the public from the degrees of the harmfulness of contaminated foods has become a daunting task. This article highlights the causes, types, and health implications of chemical contamination in food. The food contamination could be due to naturally occurring contaminants in the environment or artificially introduced by the human. The phases of food processing, packaging, transportation, and storage are also significant contributors to food contamination. The implications of these chemical contaminants on human health are grave, ranging from mild gastroenteritis to fatal cases of hepatic, renal, and neurological syndromes. Although, the government regulates such chemicals in the eatables by prescribing minimum limits that are safe for human consumption yet measures still need to be taken to curb food contamination entirely. Therefore, a variety of food needs to be inspected and measured for the presence of chemical contaminants. The preventative measures pertaining about the food contaminants problems are pointed out and discussed. PMID:29204118

The Sources of Chemical Contaminants in Food and Their Health Implications.

PubMed

Rather, Irfan A; Koh, Wee Yin; Paek, Woon K; Lim, Jeongheui

2017-01-01

Food contamination is a matter of serious concern, as the high concentration of chemicals present in the edibles poses serious health risks. Protecting the public from the degrees of the harmfulness of contaminated foods has become a daunting task. This article highlights the causes, types, and health implications of chemical contamination in food. The food contamination could be due to naturally occurring contaminants in the environment or artificially introduced by the human. The phases of food processing, packaging, transportation, and storage are also significant contributors to food contamination. The implications of these chemical contaminants on human health are grave, ranging from mild gastroenteritis to fatal cases of hepatic, renal, and neurological syndromes. Although, the government regulates such chemicals in the eatables by prescribing minimum limits that are safe for human consumption yet measures still need to be taken to curb food contamination entirely. Therefore, a variety of food needs to be inspected and measured for the presence of chemical contaminants. The preventative measures pertaining about the food contaminants problems are pointed out and discussed.

An approach for assessing potential sediment-bound contaminant threats near the intake of a drinking water treatment plant.

PubMed

Chen, Fei; Anderson, William B; Huck, Peter M

2013-01-01

To assist in assessing a potential contaminated sediment threat near a drinking water intake in a large lake, a technique known as the fingerprint analysis of leachate contaminants (FALCON), was investigated and enhanced to help draw more statistically significant definitive conclusions. This represents the first application of this approach, originally developed by the USEPA to characterize and track leachate penetration in groundwater and contaminant migration from waste and landfill sites, in a large lake from the point-of-view of source water protection. FALCON provided valuable information regarding contaminated sediment characterization, source attribution, and transport within a surface water context without the need for knowledge of local hydrodynamic conditions, potentially reducing reliance on complicated hydrodynamic analysis. A t-test to evaluate the significance of correlations was shown to further enhance the FALCON procedure. In this study, the sensitivity of FALCON was found to be improved by using concentration data from both conserved organics and heavy metals in combination. Furthermore, data analysis indicated that it may be possible to indirectly assess the success of remediation efforts (and the corresponding need to plan for a treatment upgrade in the event of escalating contaminant concentrations) by examining the temporal change in correlation between the source and intake sediment fingerprints over time. This method has potential for widespread application in situations where conserved contaminants such as heavy metals and higher molecular weight polycyclic aromatic hydrocarbons (PAHs), are being or have previously been deposited in sediment somewhere in, or within range of, an intake protection zone. Copyright © 2012 Elsevier Ltd. All rights reserved.

A comparison of the reproductive physiology of largemouth bass, Micropterus salmoides, collected from the Escambia and Blackwater Rivers in Florida.

PubMed

Orlando, E F; Denslow, N D; Folmar, L C; Guillette, L J

1999-03-01

Largemouth bass (LMB), Micropterus salmoides, were taken from the Escambia River (contaminated site) and the Blackwater River (reference site) near Pensacola, Florida. The Escambia River collection occurred downstream of the effluent from two identified point sources of pollution. These point sources included a coal-fired electric power plant and a chemical company. Conversely, the Blackwater River's headwaters and most of its length flow within a state park. Although there is some development on the lower part of the Blackwater River, fish were collected in the more pristine upper regions. Fish were captured by electroshocking and were maintained in aerated coolers. Physical measurements were obtained, blood was taken, and liver and gonads were removed. LMB plasma was assayed for the concentration of 17ss-estradiol (E2) and testosterone using validated radioimmunoassays. The presence of vitellogenin was determined by gel electrophoresis (SDS-PAGE) and Western blotting using a monoclonal antibody validated for largemouth bass vitellogenin. No differences in plasma concentrations of E2 or testosterone were observed in females from the two sites. Similarly, males exhibited no difference in plasma E2. However, plasma testosterone was lower in the males from the contaminated site, as compared to the reference site. Vitellogenic males occurred only at the contaminated site. Additionally, liver mass was proportionately higher in males from the contaminated site, as compared to males from the reference site. These data suggest that reproductive steroid levels may have been altered by increased hepatic enzyme activity, and the presence of vitellogenic males indicates that an exogenous source of estrogen was present in the Escambia River.

A comparison of the reproductive physiology of largemouth bass, Micropterus salmoides, collected from the Escambia and Blackwater Rivers in Florida.

PubMed Central

Orlando, E F; Denslow, N D; Folmar, L C; Guillette, L J

1999-01-01

Largemouth bass (LMB), Micropterus salmoides, were taken from the Escambia River (contaminated site) and the Blackwater River (reference site) near Pensacola, Florida. The Escambia River collection occurred downstream of the effluent from two identified point sources of pollution. These point sources included a coal-fired electric power plant and a chemical company. Conversely, the Blackwater River's headwaters and most of its length flow within a state park. Although there is some development on the lower part of the Blackwater River, fish were collected in the more pristine upper regions. Fish were captured by electroshocking and were maintained in aerated coolers. Physical measurements were obtained, blood was taken, and liver and gonads were removed. LMB plasma was assayed for the concentration of 17ss-estradiol (E2) and testosterone using validated radioimmunoassays. The presence of vitellogenin was determined by gel electrophoresis (SDS-PAGE) and Western blotting using a monoclonal antibody validated for largemouth bass vitellogenin. No differences in plasma concentrations of E2 or testosterone were observed in females from the two sites. Similarly, males exhibited no difference in plasma E2. However, plasma testosterone was lower in the males from the contaminated site, as compared to the reference site. Vitellogenic males occurred only at the contaminated site. Additionally, liver mass was proportionately higher in males from the contaminated site, as compared to males from the reference site. These data suggest that reproductive steroid levels may have been altered by increased hepatic enzyme activity, and the presence of vitellogenic males indicates that an exogenous source of estrogen was present in the Escambia River. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 PMID:10064549

Contamination Control in Hybrid Microelectronic Modules. Part 1: Identification of Critical Process and Contaminants

NASA Technical Reports Server (NTRS)

Himmel, R. P.

1975-01-01

Various hybrid processing steps, handling procedures, and materials are examined in an attempt to identify sources of contamination and to propose methods for the control of these contaminants. It is found that package sealing, assembly, and rework are especially susceptible to contamination. Moisture and loose particles are identified as the worst contaminants. The points at which contaminants are most likely to enter the hybrid package are also identified, and both general and specific methods for their detection and control are developed. In general, the most effective controls for contaminants are: clean working areas, visual inspection at each step of the process, and effective cleaning at critical process steps. Specific methods suggested include the detection of loose particles by a precap visual inspection, by preseal and post-seal electrical testing, and by a particle impact noise test. Moisture is best controlled by sealing all packages in a clean, dry, inert atmosphere after a thorough bake-out of all parts.

Morphological Deformities as Biomarkers in Fish from Contaminated Rivers in Taiwan

PubMed Central

Sun, Peter Lin; Hawkins, William E.; Overstreet, Robin M.; Brown-Peterson, Nancy J.

2009-01-01

Tilapia (Oreochromis spp.) were collected seasonally from four contaminated rivers in southwestern Taiwan for studies of morphological deformities that could be used as biomarkers of contamination. Morphological deformities found in tilapia were separated into 15 categories. Overall, the prevalence of deformities such as split fins, lower lip extension and gill deformities were significantly related to various water quality parameters, including low DO and high ammonium, lead and zinc concentrations. The persistence of tilapia in polluted waters and the development of a suite of morphological deformities suggest that tilapia can be used as sentinels of non-point source pollution in rivers. PMID:19742162

Landsat change detection can aid in water quality monitoring

NASA Technical Reports Server (NTRS)

Macdonald, H. C.; Steele, K. F.; Waite, W. P.; Shinn, M. R.

1977-01-01

Comparison between Landsat-1 and -2 imagery of Arkansas provided evidence of significant land use changes during the 1972-75 time period. Analysis of Arkansas historical water quality information has shown conclusively that whereas point source pollution generally can be detected by use of water quality data collected by state and federal agencies, sampling methodologies for nonpoint source contamination attributable to surface runoff are totally inadequate. The expensive undertaking of monitoring all nonpoint sources for numerous watersheds can be lessened by implementing Landsat change detection analyses.

Development of a robust methos for isolation of shiga toxin positive Escherichia coli (STEC) from fecal, plant, soil and water samples from leafy greens production region in California

USDA-ARS?s Scientific Manuscript database

Pre-harvest contamination of produce occurs by the transport of pathogenic bacteria from point sources in the surrounding environment. To identify vertebrate sources, we surveyed livestock and wildlife over a 2.5 year period on 33 farms and ranches in the Salinas valley region of California for the ...

Effects of Source- versus Household Contamination of Tubewell Water on Child Diarrhea in Rural Bangladesh: A Randomized Controlled Trial

PubMed Central

Unicomb, Leanne; Arnold, Benjamin F.; Colford Jr., John M.; Luby, Stephen P.

2015-01-01

Background Shallow tubewells are the primary drinking water source for most rural Bangladeshis. Fecal contamination has been detected in tubewells, at low concentrations at the source and at higher levels at the point of use. We conducted a randomized controlled trial to assess whether improving the microbiological quality of tubewell drinking water by household water treatment and safe storage would reduce diarrhea in children <2 years in rural Bangladesh. Methods We randomly assigned 1800 households with a child aged 6-18 months (index child) into one of three arms: chlorine plus safe storage, safe storage and control. We followed households with monthly visits for one year to promote the interventions, track their uptake, test participants’ source and stored water for fecal contamination, and record caregiver-reported child diarrhea prevalence (primary outcome). To assess reporting bias, we also collected data on health outcomes that are not expected to be impacted by our interventions. Findings Both interventions had high uptake. Safe storage, alone or combined with chlorination, reduced heavy contamination of stored water. Compared to controls, diarrhea in index children was reduced by 36% in the chlorine plus safe storage arm (prevalence ratio, PR = 0.64, 0.55-0.73) and 31% in the safe storage arm (PR = 0.69, 0.60-0.80), with no difference between the two intervention arms. One limitation of the study was the non-blinded design with self-reported outcomes. However, the prevalence of health outcomes not expected to be impacted by water interventions did not differ between study arms, suggesting minimal reporting bias. Conclusions Safe storage significantly improved drinking water quality at the point of use and reduced child diarrhea in rural Bangladesh. There was no added benefit from combining safe storage with chlorination. Efforts should be undertaken to implement and evaluate long-term efforts for safe water storage in Bangladesh. Trial Registration ClinicalTrials.gov NCT01350063 PMID:25816342

On-farm and postharvest processing sources of bacterial contamination to melon rinds.

PubMed

Gagliardi, J V; Millner, P D; Lester, G; Ingram, D

2003-01-01

Multistate and international foodborne illness outbreaks, particularly involving cantaloupe and often involving rare Salmonella spp., have increased dramatically over the past 13 years. This study assessed the sources and extent of melon rind contamination in production fields and at processing and packing facilities. In the spring of 1999, cantaloupe (Cucumis melo L. [reticulatus group] cv. Cruiser) sampled from two sites in the Rio Grande River Valley showed that postharvest-processed melon rinds often had greater plate counts of bacterial contaminants than field-fresh melons. Cantaloupe in the field had 2.5 to 3.5 log CFU g(-1) rind total coliforms by aerobic plate counts, whereas washed melons had 4.0 to 5.0 log CFU g(-1). In the fall of 1999, coliforms on honeydew melons (C. melo [inodorous group] cv. Honey Brew) ranged from 2.6 to 3.7 log CFU g(-1) after processing, and total and fecal coliforms and enterococci never fell below 2.5 log CFU g(-1). A hydrocooler at another site contaminated cantaloupe rinds with up to 3.4 log CFU g(-1) total and fecal enterococci; a secondary rinse with chlorinated water incompletely removed these bacteria. Sources of coliforms and enterococci were at high levels in melon production soils, especially in furrows that were flood irrigated, in standing water at one field, and in irrigation water at both sites. At one processing facility, wash water pumped from the Rio Grande River may not have been sufficiently disinfected prior to use. Because soil, irrigation water, and process water were potential sources of bacterial contamination, monitoring and management on-farm and at processing and packing facilities should focus on water quality as an important control point for growers and packers to reduce bacterial contamination on melon rinds.

Soil heavy metal pollution and risk assessment associated with the Zn-Pb mining region in Yunnan, Southwest China.

PubMed

Cheng, Xianfeng; Danek, Tomas; Drozdova, Jarmila; Huang, Qianrui; Qi, Wufu; Zou, Liling; Yang, Shuran; Zhao, Xinliang; Xiang, Yungang

2018-03-07

The environmental assessment and identification of sources of heavy metals in Zn-Pb ore deposits are important steps for the effective prevention of subsequent contamination and for the development of corrective measures. The concentrations of eight heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) in soils from 40 sampling points around the Jinding Zn-Pb mine in Yunnan, China, were analyzed. An environmental quality assessment of the obtained data was performed using five different contamination and pollution indexes. Statistical analyses were performed to identify the relations among the heavy metals and the pH in soils and possible sources of pollution. The concentrations of As, Cd, Pb, and Zn were extremely high, and 23, 95, 25, and 35% of the samples, respectively, exceeded the heavy metal limits set in the Chinese Environmental Quality Standard for Soils (GB15618-1995, grade III). According to the contamination and pollution indexes, environmental risks in the area are high or extremely high. The highest risk is represented by Cd contamination, the median concentration of which exceeds the GB15618-1995 limit. Based on the combination of statistical analyses and geostatistical mapping, we identified three groups of heavy metals that originate from different sources. The main sources of As, Cd, Pb, Zn, and Cu are mining activities, airborne particulates from smelters, and the weathering of tailings. The main sources of Hg are dust fallout and gaseous emissions from smelters and tailing dams. Cr and Ni originate from lithogenic sources.

Seasonal variation of nitrogen-concentration in the surface water and its relationship with land use in a catchment of northern China.

PubMed

Chen, Li-ding; Peng, Hong-jia; Fu, Bo-Jie; Qiu, Jun; Zhang, Shu-rong

2005-01-01

Surface waters can be contaminated by human activities in two ways: (1) by point sources, such as sewage treatment discharge and storm-water runoff; and (2) by non-point sources, such as runoff from urban and agricultural areas. With point-source pollution effectively controlled, non-point source pollution has become the most important environmental concern in the world. The formation of non-point source pollution is related to both the sources such as soil nutrient, the amount of fertilizer and pesticide applied, the amount of refuse, and the spatial complex combination of land uses within a heterogeneous landscape. Land-use change, dominated by human activities, has a significant impact on water resources and quality. In this study, fifteen surface water monitoring points in the Yuqiao Reservoir Basin, Zunhua, Hebei Province, northern China, were chosen to study the seasonal variation of nitrogen concentration in the surface water. Water samples were collected in low-flow period (June), high-flow period (July) and mean-flow period (October) from 1999 to 2000. The results indicated that the seasonal variation of nitrogen concentration in the surface water among the fifteen monitoring points in the rainfall-rich year is more complex than that in the rainfall-deficit year. It was found that the land use, the characteristics of the surface river system, rainfall, and human activities play an important role in the seasonal variation of N-concentration in surface water.

Mapping ecosystem service indicators in a Great Lakes estuarine Area of Concern

EPA Science Inventory

Estuaries provide multiple ecosystem services from which humans benefit. Currently, thirty-six Great Lakes estuaries in the United States and Canada are designated as Areas of Concern (AOCs) due to a legacy of chemical contamination, degraded habitat, and non-point-source polluti...

FISH TISSUE QUALITY IN NEAR-COASTAL AREAS OF THE GULF OF MEXICO RECEIVING POINT SOURCE DISCHARGES

EPA Science Inventory

The objective of this study was to determine inorganic and organic contaminant concentrations in edible tissue of fish collected from eight coastal areas receiving wastewater discharges and from two reference locations. Trace metal residues were statistically similar regardless o...

Perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) in soils and groundwater of a U.S. metropolitan area: migration and implications for human exposure.

PubMed

Xiao, Feng; Simcik, Matt F; Halbach, Thomas R; Gulliver, John S

2015-04-01

Perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) are emerging anthropogenic compounds that have recently become the target of global concern due to their ubiquitous presence in the environment, persistence, and bioaccumulative properties. This study was carried out to investigate the migration of PFOS and PFOA in soils and groundwater in a U.S. metropolitan area. We observed elevated levels in surface soils (median: 12.2 ng PFOS/g dw and 8.0 ng PFOA/g dw), which were much higher than the soil-screening levels for groundwater protection developed in this study. The measured levels in subsurface soils show a general increase with depth, suggesting a downward movement toward the groundwater table and a potential risk of aquifer contamination. Furthermore, concentrations of PFOS and PFOA in monitoring wells in the source zone varied insignificantly over 5 years (2009-2013), suggesting limited or no change in either the source or the magnitude of the source. The analysis also shows that natural processes of dispersion and dilution can significantly attenuate the groundwater contamination; the adsorption on aquifer solids, on the other hand, appears to have limited effects on the transport of PFOS and PFOA in the aquifer. The probabilistic exposure assessment indicates that ingestion of contaminated groundwater constitutes a much more important exposure route than ingestion of contaminated soil. Overall, the results suggest that (i) the transport of PFOS and PFOA is retarded in the vadose zone, but not in the aquifer; (ii) the groundwater contamination of PFOS and PFOA often follows their release to surface soils by years, if not decades; and (iii) the aquifer can be a major source of exposure for communities living near point sources. Copyright © 2014 Elsevier Ltd. All rights reserved.

Nonpoint and Point Sources of Nitrogen in Major Watersheds of the United States

USGS Publications Warehouse

Puckett, Larry J.

1994-01-01

Estimates of nonpoint and point sources of nitrogen were made for 107 watersheds located in the U.S. Geological Survey's National Water-Quality Assessment Program study units throughout the conterminous United States. The proportions of nitrogen originating from fertilizer, manure, atmospheric deposition, sewage, and industrial sources were found to vary with climate, hydrologic conditions, land use, population, and physiography. Fertilizer sources of nitrogen are proportionally greater in agricultural areas of the West and the Midwest than in other parts of the Nation. Animal manure contributes large proportions of nitrogen in the South and parts of the Northeast. Atmospheric deposition of nitrogen is generally greatest in areas of greatest precipitation, such as the Northeast. Point sources (sewage and industrial) generally are predominant in watersheds near cities, where they may account for large proportions of the nitrogen in streams. The transport of nitrogen in streams increases as amounts of precipitation and runoff increase and is greatest in the Northeastern United States. Because no single nonpoint nitrogen source is dominant everywhere, approaches to control nitrogen must vary throughout the Nation. Watershed-based approaches to understanding nonpoint and point sources of contamination, as used by the National Water-Quality Assessment Program, will aid water-quality and environmental managers to devise methods to reduce nitrogen pollution.

CMI Remedy Selection for HE- and Barium-Contaminated Vadose Zone and Alluvium at LANL

NASA Astrophysics Data System (ADS)

Hickmott, D.; Reid, K.; Pietz, J.; Ware, D.

2008-12-01

A high explosives (HE) machining building outfall at Los Alamos National Laboratory's Technical Area 16 discharged millions of gallons of HE- and barium-contaminated water into the Canon de Valle watershed. The effluent contaminated surface soils, the alluvial aquifer, vadose zone waters, and deep-perched and regional groundwaters with HE and barium, frequently at levels greater than regulatory standards. Site characterization studies began in 1995 and included extensive monitoring of surface water, groundwater, soils, and subsurface solid media. Hydrogeologic and geophysical studies were conducted to help understand contaminant transport mechanisms and pathways. Results from the characterization studies were used to develop a site conceptual model. In 2000 the principal source area was removed. The ongoing Corrective Measure Study (CMS) and Corrective Measure Implementation (CMI) focus on residual vadose zone contamination and on the contaminated alluvial system. Regulators recently selected a CMI remedy that combined: 1) augmented source removal; 2) grouting of an HE- contaminated surge bed; 3) deployment of Stormwater Management System (SMS) stormfilters in contaminated springs; and 4) permeable reactive barriers (PRBs) in contaminated alluvium. The hydrogeologic conceptual model for the vadose zone and alluvial system as well as the status of the canyon as habitat for the Mexican Spotted Owl were key factors in selection of these minimal-environmental-impact remedies. The heterogeneous vadose zone, characterized by flow and contaminant transport in fractures and in surge beds, requires contaminant treatment at a point of discharge. The canyon PRB is being installed to capture water and contaminants prior to infiltration into the vadose zone. Pilot-scale testing of the SMS and lab-scale batch and column tests of a range of media suggest that granular activated carbon, zeolite, and gypsum may be effective media for removal of HE and/or barium from contaminated waters.

Three-dimensional data interpolation for environmental purpose: lead in contaminated soils in southern Brazil.

PubMed

Piedade, Tales Campos; Melo, Vander Freitas; Souza, Luiz Cláudio Paula; Dieckow, Jeferson

2014-09-01

Monitoring of heavy metal contamination plume in soils can be helpful in establishing strategies to minimize its hazardous impacts to the environment. The objective of this study was to apply a new approach of visualization, based on tridimensional (3D) images, of pseudo-total (extracted with concentrated acids) and exchangeable (extracted with 0.5 mol L(-1) Ca(NO3)2) lead (Pb) concentrations in soils of a mining and metallurgy area to determine the spatial distribution of this pollutant and to estimate the most contaminated soil volumes. Tridimensional images were obtained after interpolation of Pb concentrations of 171 soil samples (57 points × 3 depths) with regularized spline with tension in a 3D function version. The tridimensional visualization showed great potential of use in environmental studies and allowed to determine the spatial 3D distribution of Pb contamination plume in the area and to establish relationships with soil characteristics, landscape, and pollution sources. The most contaminated soil volumes (10,001 to 52,000 mg Pb kg(-1)) occurred near the metallurgy factory. The main contamination sources were attributed to atmospheric emissions of particulate Pb through chimneys. The large soil volume estimated to be removed to industrial landfills or co-processing evidenced the difficulties related to this practice as a remediation strategy.

Higher Storage Temperature Causes Greater Salmonella enterica Serovar Typhimurium Internal Penetration of Artificially Contaminated, Commercially Available, Washed Free Range Eggs.

PubMed

Whiley, Alice; Fallowfield, Howard; Ross, Kirstin; McEvoy, Vanessa; Whiley, Harriet

2016-07-01

Foodborne salmonellosis is a major public health concern, with contaminated eggs identified as a significant source of infection. In Australia, the most prevalent cause of salmonellosis from eggs is Salmonella enterica subsp. enterica serovar Typhimurium. This study explored the effect of temperature after 1, 7, 14, 21, and 28 days of storage on commercially available washed free range eggs, artificially contaminated with Salmonella Typhimurium on the external surface. At each time point, the external surface of the egg, the crushed eggshell, and the internal egg yolk and albumen were analyzed for Salmonella. After 28 days of storage, 25% of eggs stored at 4°C, 50% of eggs stored at 14°C, and 100% of eggs stored at 23 and 35°C were internally contaminated with Salmonella. After 1 day of storage, more than 50% of all eggs had Salmonella present in the crushed shell after the external surface had been disinfected with ethanol. This is the first study to demonstrate that refrigeration reduced the potential for Salmonella Typhimurium to penetrate the eggshell membrane and internally contaminate table eggs commercially available in Australia. It also suggests that the processes of cracking eggs may be a source of cross-contamination within the kitchen.

Reply to comment on "Validation of two innovative methods to measure contaminant mass flux in groundwater" by Goltz et al. (2009)

NASA Astrophysics Data System (ADS)

Goltz, Mark N.; Huang, Junqi

2014-12-01

We thank Sun (2014) for his comment on our paper, Goltz et al. (2009). The commenter basically makes two points: (1) equation (6) in Goltz et al. (2009) is incorrect, and (2) screen loss should be further considered as a source of error in the modified integral pump test (MIPT) experiment. We will address each of these points, below.

Occurrence of Blastocystis sp. in water catchments at Malay villages and Aboriginal settlement during wet and dry seasons in Peninsular Malaysia

PubMed Central

Noradilah, Samseh Abdullah; Lee, Ii Li; Anuar, Tengku Shahrul; Salleh, Fatmah Md; Abdul Manap, Siti Nor Azreen; Mohd Mohtar, Noor Shazleen Husnie; Azrul, Syed Muhamad; Abdullah, Wan Omar

2016-01-01

In the tropics, there are too few studies on isolation of Blastocystis sp. subtypes from water sources; in addition, there is also an absence of reported studies on the occurrence of Blastocystis sp. subtypes in water during different seasons. Therefore, this study was aimed to determine the occurrence of Blastocystis sp. subtypes in river water and other water sources that drained aboriginal vicinity of highly endemic intestinal parasitic infections during wet and dry seasons. Water samples were collected from six sampling points of Sungai Krau (K1–K6) and a point at Sungai Lompat (K7) and other water sources around the aboriginal villages. The water samples were collected during both seasons, wet and dry seasons. Filtration of the water samples were carried out using a flatbed membrane filtration system. The extracted DNA from concentrated water sediment was subjected to single round polymerase chain reaction and positive PCR products were subjected to sequencing. All samples were also subjected to filtration and cultured on membrane lactose glucuronide agar for the detection of faecal coliforms. During wet season, Blastocystis sp. ST1, ST2 and ST3 were detected in river water samples. Blastocystis sp. ST3 occurrence was sustained in the river water samples during dry season. However Blastocystis sp. ST1 and ST2 were absent during dry season. Water samples collected from various water sources showed contaminations of Blastocystis sp. ST1, ST2, ST3 and ST4, during wet season and Blastocystis sp. ST1, ST3, ST8 and ST10 during dry season. Water collected from all river sampling points during both seasons showed growth of Escherichia coli and Enterobacter aerogenes, indicating faecal contamination. In this study, Blastocystis sp. ST3 is suggested as the most robust and resistant subtype able to survive in any adverse environmental condition. Restriction and control of human and animal faecal contaminations to the river and other water sources shall prevent the transmission of Blastocystis sp. to humans and animals in this aboriginal community. PMID:27761331

Selecting remediation goals by assessing the natural attenuation capacity of groundwater systems

USGS Publications Warehouse

Chapelle, Francis H.; Bradley, Paul M.

1998-01-01

Remediation goals for the source areas of a chlorinated ethene‐contaminated groundwater plume were identified by assessing the natural attenuation capacity of the aquifer system. The redox chemistry of the site indicates that sulfate‐reducing (H2 ∼ 2 nanomoles [nM]) per liter conditions near the contaminant source grade to Fe(III)‐reducing conditions (H2 ∼ 0.5 nM) downgradient of the source. Sulfate‐reducing conditions facilitate the initial reduction of perchloroethene (PCE) to trichloroethene (TCE), cis‐dichloroethene (cis‐DCE), and vinyl chloride (VC). Subsequently, the Fe(III)‐reducing conditions drive the oxidation of cis‐DCE and VC to carbon dioxide and chloride. This sequence gives the aquifer a substantial capacity for biodegrading chlorinated ethenes. Natural attenuation capacity (the slope of the steady‐state contaminant concentration profile along a groundwater flowpath) is a function of biodegradation rates, aquifer dispersive characteristics, and groundwater flow velocity. The natural attenuation capacity at the Kings Bay, Georgia site was assessed by estimating groundwater flowrates (∼0.23 ± 0.12 m/d) and aquifer dispersivity (∼1 m) from hydrologic and scale considerations. Apparent biodegradation rate constants (PCE and TCE ∼ 0.01 d−1; cis‐DCE and VC ∼ 0.025 d−1) were estimated from observed contaminant concentration changes along aquifer flowpaths. A boundary‐value problem approach was used to estimate levels to which contaminant concentrations in the source areas must be lowered (by engineered removal), or groundwater flow velocities lowered (by pumping) for the natural attenuation capacity to achieve maximum concentration limits (MCLs) prior to reaching a predetermined regulatory point of compliance.

Chemical and biological tracers to determine groundwater flow in karstic aquifer, Yucatan Peninsula

NASA Astrophysics Data System (ADS)

Lenczewski, M.; Leal-Bautista, R. M.; McLain, J. E.

2013-05-01

Little is known about the extent of pollution in groundwater in the Yucatan Peninsula; however current population growth, both from international tourism and Mexican nationals increases the potential for wastewater release of a vast array of contaminants including personal care products, pharmaceuticals (Rx), and pathogenic microorganisms. Pathogens and Rx in groundwater can persist and can be particularly acute in this region where high permeability of the karst bedrock and the lack of top soil permit the rapid transport of contaminants into groundwater aquifers. The objective of this research is to develop and utilize novel biological and chemical source tracking methods to distinguish between different sources of anthropogenic pollution in degraded groundwater. Although several methods have been used successfully to track fecal contamination sources in small scale studies, little is known about their spatial limitations, as source tracking studies rarely include sample collection over a wide geographical area and with different sources of water. In addition, although source tracking methods to distinguish human from animal fecal contamination are widely available, this work has developed source tracking distinguish between separate human populations is highly unique. To achieve this objective, we collected water samples from a series of drinking wells, cenotes (sinkholes), wastewater treatment plants, and injection wells across the Yucatan Peninsula and examine potential source tracers within the collected water samples. The result suggests that groundwater sources impacted by tourist vs. local populations contain different chemical stressors. This work has developed a more detailed understanding of the presence and persistence of personal care products, pharmaceuticals, and fecal indicators in a karstic system; such understanding will be a vital component for the protection Mexican groundwater and human health. Quantification of different pollution sources within groundwater samples identified point sources of pollution, identify potential remediation strategies, and contribute to an improved understanding of the environmental impact of tourism and tourism-generated waste products on this groundwater-dependent ecosystem.

Future research needs involving pathogens in groundwater

NASA Astrophysics Data System (ADS)

Bradford, Scott A.; Harvey, Ronald W.

2017-06-01

Contamination of groundwater by enteric pathogens has commonly been associated with disease outbreaks. Proper management and treatment of pathogen sources are important prerequisites for preventing groundwater contamination. However, non-point sources of pathogen contamination are frequently difficult to identify, and existing approaches for pathogen detection are costly and only provide semi-quantitative information. Microbial indicators that are readily quantified often do not correlate with the presence of pathogens. Pathogens of emerging concern and increasing detections of antibiotic resistance among bacterial pathogens in groundwater are topics of growing concern. Adequate removal of pathogens during soil passage is therefore critical for safe groundwater extraction. Processes that enhance pathogen transport (e.g., high velocity zones and preferential flow) and diminish pathogen removal (e.g., reversible retention and enhanced survival) are of special concern because they increase the risk of groundwater contamination, but are still incompletely understood. Improved theory and modeling tools are needed to analyze experimental data, test hypotheses, understand coupled processes and controlling mechanisms, predict spatial and/or temporal variability in model parameters and uncertainty in pathogen concentrations, assess risk, and develop mitigation and best management approaches to protect groundwater.

Future research needs involving pathogens in groundwater

USGS Publications Warehouse

Bradford, Scott A.; Harvey, Ronald W.

2017-01-01

Contamination of groundwater by enteric pathogens has commonly been associated with disease outbreaks. Proper management and treatment of pathogen sources are important prerequisites for preventing groundwater contamination. However, non-point sources of pathogen contamination are frequently difficult to identify, and existing approaches for pathogen detection are costly and only provide semi-quantitative information. Microbial indicators that are readily quantified often do not correlate with the presence of pathogens. Pathogens of emerging concern and increasing detections of antibiotic resistance among bacterial pathogens in groundwater are topics of growing concern. Adequate removal of pathogens during soil passage is therefore critical for safe groundwater extraction. Processes that enhance pathogen transport (e.g., high velocity zones and preferential flow) and diminish pathogen removal (e.g., reversible retention and enhanced survival) are of special concern because they increase the risk of groundwater contamination, but are still incompletely understood. Improved theory and modeling tools are needed to analyze experimental data, test hypotheses, understand coupled processes and controlling mechanisms, predict spatial and/or temporal variability in model parameters and uncertainty in pathogen concentrations, assess risk, and develop mitigation and best management approaches to protect groundwater.

StreamVOC - A deterministic source-apportionment model to estimate volatile organic compound concentrations in rivers and streams

USGS Publications Warehouse

Asher, William E.; Bender, David A.; Zogorski, John S.; Bartholomay, Roy C.

2006-01-01

This report documents the construction and verification of the model, StreamVOC, that estimates (1) the time- and position-dependent concentrations of volatile organic compounds (VOCs) in rivers and streams as well as (2) the source apportionment (SA) of those concentrations. The model considers how different types of sources and loss processes can act together to yield a given observed VOC concentration. Reasons for interest in the relative and absolute contributions of different sources to contaminant concentrations include the need to apportion: (1) the origins for an observed contamination, and (2) the associated human and ecosystem risks. For VOCs, sources of interest include the atmosphere (by absorption), as well as point and nonpoint inflows of VOC-containing water. Loss processes of interest include volatilization to the atmosphere, degradation, and outflows of VOC-containing water from the stream to local ground water. This report presents the details of StreamVOC and compares model output with measured concentrations for eight VOCs found in the Aberjona River at Winchester, Massachusetts. Input data for the model were obtained during a synoptic study of the stream system conducted July 11-13, 2001, as part of the National Water-Quality Assessment (NAWQA) Program of the U.S. Geological Survey. The input data included a variety of basic stream characteristics (for example, flows, temperature, and VOC concentrations). The StreamVOC concentration results agreed moderately well with the measured concentration data for several VOCs and provided compound-dependent SA estimates as a function of longitudinal distance down the river. For many VOCs, the quality of the agreement between the model-simulated and measured concentrations could be improved by simple adjustments of the model input parameters. In general, this study illustrated: (1) the considerable difficulty of quantifying correctly the locations and magnitudes of ground-water-related sources of contamination in streams; and (2) that model-based estimates of stream VOC concentrations are likely to be most accurate when the major sources are point sources or tributaries where the spatial extent and magnitude of the sources are tightly constrained and easily determined.

Chemical mixtures and environmental effects: a pilot study to assess ecological exposure and effects in streams

USGS Publications Warehouse

Buxton, Herbert T.; Reilly, Timothy J.; Kuivila, Kathryn; Kolpin, Dana W.; Bradley, Paul M.; Villeneuve, Daniel L.; Mills, Marc A.

2015-01-01

Assessment and management of the risks of exposure to complex chemical mixtures in streams are priorities for human and environmental health organizations around the world. The current lack of information on the composition and variability of environmental mixtures and a limited understanding of their combined effects are fundamental obstacles to timely identification and prevention of adverse human and ecological effects of exposure. This report describes the design of a field-based study of the composition and biological activity of chemical mixtures in U.S. stream waters affected by a wide range of human activities and contaminant sources. The study is a collaborative effort by the U.S. Geological Survey and the U.S. Environmental Protection Agency. Scientists sampled 38 streams spanning 24 States and Puerto Rico. Thirty-four of the sites were located in watersheds impacted by multiple contaminant sources, including industrial and municipal wastewater discharges, crop and animal agricultural runoff, urban runoff, and other point and nonpoint contaminant sources. The remaining four sites were minimally development reference watersheds. All samples underwent comprehensive chemical and biological characterization, including sensitive and specific direct analysis for over 700 dissolved organic and inorganic chemicals and field parameters, identification of unknown contaminants (environmental diagnostics), and a variety of bioassays to evaluate biological activity and toxicity.

COMPARISON OF THE REPRODUCTIVE PHYSIOLOGY OF LARGEMOUTH BASS, MICROPTERUS SALMOIDES, COLLECTED FROM THE ESCAMBIA AND BLACKWATER RIVERS IN FLORIDA

EPA Science Inventory

Largemouth bass (LMB), Micropterus salmoides, were taken from the Escambia River (contaminated site) and the Blackwater River (reference site) near Pensacola, Florida. The Escambia River collection occurred downstream of the effluent from two identified point sources of pollution...

Serendipitous observations of asteroids in Herschel PACS and SPIRE maps

NASA Astrophysics Data System (ADS)

Szakáts, R.; Kiss, Cs.; Marton, G.; Varga-Verebélyi, E.; Müller, T.; Pál, A.

2017-09-01

We present our methods and results in finding serendipitous solar system objects on Herschel PACS and SPIRE maps. We can use this data to supplement the Herschel PACS and SPIRE point source catalogs with flags of possible contamination and to obtain thermal infrared fluxes for these asteroids.

TRANSPORT AND SURVIVAL OF VIRUSES IN THE SUBSURFACE PROCESSES, EXPERIMENTS, AND SIMULATION MODELS

EPA Science Inventory

The remediation of ground water contaminated with waterborne pathogens, in particular with viruses, is based on their probable or actual ability to be transported from the source of origin to a point of withdrawal while maintaining the capacity to cause infections. The transport ...

Denitrification and dilution along fracture flowpaths influence the recovery of a bedrock aquifer from nitrate contamination.

PubMed

Kim, Jonathan J; Comstock, Jeff; Ryan, Peter; Heindel, Craig; Koenigsberger, Stephan

2016-11-01

In 2000, elevated nitrate concentrations ranging from 12 to 34mg/L NO3N were discovered in groundwater from numerous domestic bedrock wells adjacent to a large dairy farm in central Vermont. Long-term plots and contours of nitrate vs. time for bedrock wells showed "little/no", "moderate", and "large" change patterns that were spatially separable. The metasedimentary bedrock aquifer is strongly anisotropic and groundwater flow is controlled by fractures, bedding/foliation, and basins and ridges in the bedrock surface. Integration of the nitrate concentration vs. time data and the physical and chemical aquifer characterization suggest two nitrate sources: a point source emanating from a waste ravine and a non-point source that encompasses the surrounding fields. Once removed, the point source of NO3 (manure deposited in a ravine) was exhausted and NO3 dropped from 34mg/L to <10mg/L after ~10years; however, persistence of NO3 in the 3 to 8mg/L range (background) reflects the long term flux of nitrates from nutrients applied to the farm fields surrounding the ravine over the years predating and including this study. Inferred groundwater flow rates from the waste ravine to either moderate change wells in basin 2 or to the shallow bedrock zone beneath the large change wells are 0.05m/day, well within published bedrock aquifer flow rates. Enrichment of (15)N and (18)O in nitrate is consistent with lithotrophic denitrification of NO3 in the presence of dissolved Mn and Fe. Once the ravine point-source was removed, denitrification and dilution collectively were responsible for the down-gradient decrease of nitrate in this bedrock aquifer. Denitrification was most influential when NO3N was >10mg/L. Our multidisciplinary methods of aquifer characterization are applicable to groundwater contamination in any complexly-deformed and metamorphosed bedrock aquifer. Copyright © 2016 Elsevier B.V. All rights reserved.

Decreasing aqueous mercury concentrations to meet the water quality criterion in fish: examining the water-fish relationship in two point-source contaminated streams.

PubMed

Mathews, Teresa J; Southworth, George; Peterson, Mark J; Roy, W Kelly; Ketelle, Richard H; Valentine, Charles; Gregory, Scott

2013-01-15

East Fork Poplar Creek (EF) and White Oak Creek (WC) are two mercury-contaminated streams located on the United States (U.S.) Department of Energy Oak Ridge Reservation in East Tennessee. East Fork Poplar Creek is the larger and more contaminated of the two, with average aqueous mercury (Hg) concentrations exceeding those in reference streams by several hundred-fold. Remedial actions over the past 20 years have decreased aqueous Hg concentrations in EF by 85% (from >1600 ng/L to <400 ng/L). Fish fillet concentrations, however, have not responded to this decrease in aqueous Hg and remain above the U.S. Environmental Protection Agency National Recommended Water Quality Criteria (NRWQC) of 0.3 mg/kg. The lack of correlation between aqueous and fish tissue Hg concentrations in this creek has led to questions regarding the usefulness of target aqueous Hg concentrations and strategies for future remediation efforts. White Oak Creek has a similar contamination history but aqueous Hg concentrations in WC are an order of magnitude lower than in EF. Despite the lower aqueous Hg concentrations (<100 ng/L), fish fillet concentrations in WC have also been above the NRWQC, making the aqueous Hg remediation goal of 200 ng/L in EF seem unlikely to result in an effective decrease in fillet Hg concentrations. Recent monitoring efforts in WC, however, suggest an aqueous total Hg threshold above which Hg bioaccumulation in fish may not respond. This new information could be useful in guiding remedial actions in EF and in other point-source contaminated streams. Published by Elsevier B.V.

Transmission and control of Salmonella in the pig feed chain: a conceptual model.

PubMed

Binter, Claudia; Straver, Judith Maria; Häggblom, Per; Bruggeman, Geert; Lindqvist, Per-Anders; Zentek, Jürgen; Andersson, Mats Gunnar

2011-03-01

Infected breeder pigs and contaminated feed represent potential sources of Salmonella introduction to fattening pig herds and may thereby cause human infections acquired via consumption of contaminated pork. Modelling approaches such as quantitative microbial risk assessment could improve the design of strategies for control and tracing of Salmonella in the feed chain. However, the construction of such models requires a thorough understanding of the dynamics of the feed chain, including production processes, microbial processes and transport logistics. The present article illustrates a conceptual model of Salmonella in the pig feed chain and explores the possibilities for quantitative modelling including identifying major gaps in data. Information was collected from peer-reviewed scientific journals, official documents and reports and by means of interviews with experts from authorities and the feed industry. Data on prevalence of Salmonella in different parts of the feed chain are difficult to compare as observed prevalence may be biased by variations in sampling procedures as well as limitations of the detection methods. There are almost no data on numbers of Salmonella in commodities of the feed chain, which often makes it difficult to evaluate risks, intervention strategies and sampling plans in a quantitative manner. Tracing the source of Salmonella contamination is hampered by the risk of cross-contamination as well as various mixing and partitioning events along the supply chain, which sometimes makes it impossible to trace the origin of a lot back to a batch or producer. Available information points to contaminated feed materials, animal vectors and persistent contamination of production environments as important sources of Salmonella in feed production. Technological procedures such as hydrothermal or acid treatment can be used to control Salmonella in feed production. However, a large fraction of pig feed is produced without decontamination procedures. Prevention of recontamination and control of moisture throughout the chain are thus critical factors for controlling Salmonella in feed production. To verify successful control it is necessary to have monitoring strategies able to detect low levels of Salmonella heterogeneously distributed in large volumes of feed and feed material in bulk. Experience from monitoring programs and research investigations indicates that sampling of dust and sweepings from control points along the production line is an efficient strategy to gain an indication of Salmonella contamination. Copyright © 2010 Elsevier B.V. All rights reserved.

Microbial Source Module (MSM): Documenting the Science ...

EPA Pesticide Factsheets

The Microbial Source Module (MSM) estimates microbial loading rates to land surfaces from non-point sources, and to streams from point sources for each subwatershed within a watershed. A subwatershed, the smallest modeling unit, represents the common basis for information consumed and produced by the MSM which is based on the HSPF (Bicknell et al., 1997) Bacterial Indicator Tool (EPA, 2013b, 2013c). Non-point sources include numbers, locations, and shedding rates of domestic agricultural animals (dairy and beef cows, swine, poultry, etc.) and wildlife (deer, duck, raccoon, etc.). Monthly maximum microbial storage and accumulation rates on the land surface, adjusted for die-off, are computed over an entire season for four land-use types (cropland, pasture, forest, and urbanized/mixed-use) for each subwatershed. Monthly point source microbial loadings to instream locations (i.e., stream segments that drain individual sub-watersheds) are combined and determined for septic systems, direct instream shedding by cattle, and POTWs/WWTPs (Publicly Owned Treatment Works/Wastewater Treatment Plants). The MSM functions within a larger modeling system that characterizes human-health risk resulting from ingestion of water contaminated with pathogens. The loading estimates produced by the MSM are input to the HSPF model that simulates flow and microbial fate/transport within a watershed. Microbial counts within recreational waters are then input to the MRA-IT model (Soller et

Bisphenol A emission factors from industrial sources and elimination rates in a sewage treatment plant.

PubMed

Fuerhacker, M

2003-01-01

Bisphenol A (BPA) is widely used for the production of epoxy resins and polycarbonate plastics and is considered an endocrine disruptor. Special in vitro test systems and animal experiments showed a weak estrogenic activity. Aquatic wildlife especially could be endangered by waste water discharges. To manage possible risks arising from BPA emissions the major fluxes need to be investigated and the sources of the contamination of municipal treatment plants need to be determined. In this study, five major industrial point sources, two different household areas and the influent and effluent of the corresponding treatment plant (WWTP) were monitored simultaneously at a plant serving 120,000 population equivalents. A paper producing plant was the major BPA contributor to the influent load of the wastewater treatment plant. All the other emissions from point sources, including the two household areas, were considerably lower. The minimum elimination rate in the WTTP could be determined at 78% with an average of 89% of the total BPA-load. For a possible pollution-forecast, or for a comparison between different point sources, emission factors based on COD-emissions were calculated for industrial and household point sources at BPA/COD-ratios between 1.4 x 10(-8) - 125 x 10(-8) and 1.3 x 10(-6) - 6.3 x 10(-6), respectively.

Temporal and spatial variation of polychlorinated biphenyls (PCBs) contamination in environmental compartments of highly polluted area in Central Russia.

PubMed

Malina, Natalia; Mazlova, Elena A

2017-10-01

This study highlights the fact that serious contamination from polychlorinated biphenyls (PCBs) still exists in Serpukhov City (Russia). The research help to determine the temporal (16- and 24-year periods) and spatial PCBs distribution in the environmental compartments of the studied region. Samples of soil, sediments, water and plants were analysed in order to establish their contamination levels. The most recent data on the Serpukhov City's soil contamination showed that the PCBs concentrations varies from 0.0009 to 1169 mg/kg depending on the sampling point and the distance from the pollution source. The temporal trends of the contamination distribution with the soil depth showed contamination migration in the upper soil layers of the highly polluted site. The high level of water pollution (11.5 μg/L) in the proximity to the contamination source and the sediments contamination (0.098-119 mg/kg) were determined, as well as the water migration pathways of the PCBs that were prevalent in the studied region. The PCB congener group (by the level of chlorination) analysis showed that heptachlorinated biphenyls were only found in the soils in close proximity to the contamination place, while biphenyls with Cl ≤ 6 were found in the soil samples downstream of the condenser plant and with Cl ≤ 5 in the soil samples upstream of the plant. The plant uptake of PCBs, even on the extremely contaminated site, was shown. In turn, this research present new knowledge necessary for the development of a contaminated territory remediation strategy. Copyright © 2017 Elsevier Ltd. All rights reserved.

Prevalence and characteristics of ESBL-producing E. coli in Dutch recreational waters influenced by wastewater treatment plants.

PubMed

Blaak, Hetty; de Kruijf, Patrick; Hamidjaja, Raditijo A; van Hoek, Angela H A M; de Roda Husman, Ana Maria; Schets, Franciska M

2014-07-16

Outside health care settings, people may acquire ESBL-producing bacteria through different exposure routes, including contact with human or animal carriers or consumption of contaminated food. However, contact with faecally contaminated surface water may also represent a possible exposure route. The current study investigated the prevalence and characteristics of ESBL-producing Escherichia coli in four Dutch recreational waters and the possible role of nearby waste water treatment plants (WWTP) as contamination source. Isolates from recreational waters were compared with isolates from WWTP effluents, from surface water upstream of the WWTPs, at WWTP discharge points, and in connecting water bodies not influenced by the studied WWTPs. ESBL-producing E. coli were detected in all four recreational waters, with an average concentration of 1.3 colony forming units/100ml, and in 62% of all samples. In surface waters not influenced by the studied WWTPs, ESBL-producing E. coli were detected in similar concentrations, indicating the existence of additional ESBL-E. coli contamination sources. Isolates with identical ESBL-genes, phylogenetic background, antibiotic resistance profiles, and sequence type, were obtained from effluent and different surface water sites in the same watershed, on the same day; occasionally this included isolates from recreational waters. Recreational waters were identified as a potential exposure source of ESBL-producing E. coli. WWTPs were shown to contribute to the presence of these bacteria in surface waters, but other (yet unidentified) sources likely co-contribute. Copyright © 2014 Elsevier B.V. All rights reserved.

Emergency drinking water treatment during source water pollution accidents in China: origin analysis, framework and technologies.

PubMed

Zhang, Xiao-Jian; Chen, Chao; Lin, Peng-Fei; Hou, Ai-Xin; Niu, Zhang-Bin; Wang, Jun

2011-01-01

China has suffered frequent source water contamination accidents in the past decade, which has resulted in severe consequences to the water supply of millions of residents. The origins of typical cases of contamination are discussed in this paper as well as the emergency response to these accidents. In general, excessive pursuit of rapid industrialization and the unreasonable location of factories are responsible for the increasing frequency of accidental pollution events. Moreover, insufficient attention to environmental protection and rudimentary emergency response capability has exacerbated the consequences of such accidents. These environmental accidents triggered or accelerated the promulgation of stricter environmental protection policy and the shift from economic development mode to a more sustainable direction, which should be regarded as the turning point of environmental protection in China. To guarantee water security, China is trying to establish a rapid and effective emergency response framework, build up the capability of early accident detection, and develop efficient technologies to remove contaminants from water.

National water summary 1986; Hydrologic events and ground-water quality

USGS Publications Warehouse

Moody, David W.; Carr, Jerry E.; Chase, Edith B.; Paulson, Richard W.

1988-01-01

Ground water is one of the most important natural resources of the United States and degradation of its quality could have a major effect on the welfare of the Nation. Currently (1985), ground water is the source of drinking water for 53 percent of the Nation's population and for more than 97 percent of its rural population. It is the source of about 40 percent of the Nation's public water supply, 33 percent of water for irrigation, and 17 percent of freshwater for selfsupplied industries.Ground water also is the source of about 40 percent of the average annual streamflow in the United States, although during long periods of little or no precipitation, ground-water discharges provide nearly all of the base streamflow. This hydraulic connection between aquifers and streams implies that if a persistent pollutant gets into an aquifer, it eventually could discharge into a stream.Information presented in the 1986 National Water Summary clearly shows that the United States has very large amounts of potable ground water available for use. Although naturally occurring constituents, such as nitrate, and human-induced substances, such as synthetic organic chemicals, frequently are detected in ground water, their concentrations usually do not exceed existing Federal or State standards or guidelines for maximum concentrations in drinking water.Troublesome contamination of ground water falls into two basic categories related to the source or sources of the contamination. Locally, high concentrations of a variety of toxic metals, organic chemicals, and petroleum products have been detected in ground water associated with point sources such as wastedisposal sites, storage-tank leaks, and hazardous chemical spills. These types of local problems commonly occur in densely populated urban areas and industrialized areas. Larger, multicounty areas also have been identified where contamination frequently is found in shallow wells. These areas generally are associated with broad-scale, or nonpoint, sources of contamination such as agricultural activities or highdensity domestic waste disposal (septic systems) in urban centers. At present, only a very small percentage of the total volume of potable ground water in the United States is contaminated from both point and nonpoint sources; however, available data, especially data about the occurrence of synthetic organic and toxic substances, generally are inadequate to determine the full extent of ground-water contamination in the Nation's aquifers or to define trends in groundwater quality. Most information about the occurrence of these substances has come from the study of individual sites or areas where contamination had already been detected or suspected.Management and protection of ground water present a major challenge to the Nation. Current and projected costs of detection and cleanup of existing ground-water contamination are staggering and, even so, complete removal of pollutants from ground water in the vicinity of some waste sites might not be technically feasible. At all levels of government, the task of protecting the resource for its most beneficial uses is difficult and controversial.Despite increasing awareness that some of the Nation's ground water is contaminated with a variety of toxic metals, synthetic organic chemicals, radionuclides, pesticides, and other contaminants that might present a long-term risk to human health, public policy towards ground-water protection is still in the formative stages. Despite increasing efforts devoted to ground-water protection by State and Federal regulatory and resource-management agencies, the extent of ground-water contamination is likely to appear to increase over the next few years because more agencies will be searching for evidence of contamination, and they will be using increasingly sensitive analytical procedures. Increased technology and expanded monitoring activities probably will detect the effects of past contamination and land uses on water quality. The significant time lag between a waterquality change in one part of an aquifer system and the effects of that change at a downgradient site, such as a well, results from the generally slow movement of ground water. This lag between cause and observed effect needs to be considered in evaluating the effectiveness of current and future ground-water policies and remedial measures.Conclusive answers to questions about the location, extent, and severity of ground-water contamination, and about trends in ground-water quality, must await further collection and analysis of data from the Nation's aquifers. Generalizations, however, can be made, and the 1986 National Water Summary, which describes the natural quality of ground-water resources in each State and the major contamination problems that have been identified as of 1986, provides a national perspective of the ground-water-quality situation.The 1986 National Water Summary follows the format of previous volumes. It contains three parts, and the contents of each of these parts are highlighted below.

A stress ecology framework for comprehensive risk assessment of diffuse pollution.

PubMed

van Straalen, Nico M; van Gestel, Cornelis A M

2008-12-01

Environmental pollution is traditionally classified as either localized or diffuse. Local pollution comes from a point source that emits a well-defined cocktail of chemicals, distributed in the environment in the form of a gradient around the source. Diffuse pollution comes from many sources, small and large, that cause an erratic distribution of chemicals, interacting with those from other sources into a complex mixture of low to moderate concentrations over a large area. There is no good method for ecological risk assessment of such types of pollution. We argue that effects of diffuse contamination in the field must be analysed in the wider framework of stress ecology. A multivariate approach can be applied to filter effects of contaminants from the many interacting factors at the ecosystem level. Four case studies are discussed (1) functional and structural properties of terrestrial model ecosystems, (2) physiological profiles of microbial communities, (3) detritivores in reedfield litter, and (4) benthic invertebrates in canal sediment. In each of these cases the data were analysed by multivariate statistics and associations between ecological variables and the levels of contamination were established. We argue that the stress ecology framework is an appropriate assessment instrument for discriminating effects of pollution from other anthropogenic disturbances and naturally varying factors.

Metals and metalloids in atmospheric dust: Use of lead isotopic analysis for source apportionment

NASA Astrophysics Data System (ADS)

Felix Villar, Omar I.

Mining activities generate aerosol in a wide range of sizes. Smelting activities produce mainly fine particles (<1 microm). On the other hand, milling, crushing and refining processes, as well tailings management, are significant sources of coarse particles (> 1 microm). The adverse effects of aerosols on human health depend mainly on two key characteristics: size and chemical composition. One of the main objectives of this research is to analyze the size distribution of contaminants in aerosol produced by mining operations. For this purpose, a Micro-Orifice Uniform Deposit Impactor (MOUDI) was utilized. Results from the MOUDI samples show higher concentrations of the toxic elements like lead and arsenic in the fine fraction (<1 microm). Fine particles are more likely to be deposited in the deeper zones of the respiratory system; therefore, they are more dangerous than coarse particles that can be filtered out in the upper respiratory system. Unfortunately, knowing the total concentration of contaminants does not give us enough information to identify the source of contamination. For this reason, lead isotopes have been introduced as fingerprints for source apportionment. Each source of lead has specific isotopic ratios; by knowing these ratios sources can be identified. During this research, lead isotopic ratios were analyzed at different sites and for different aerosol sizes. From these analyses it can be concluded that lead isotopes are a powerful tool to identify sources of lead. Mitigation strategies could be developed if the source of contamination is well defined. Environmental conditions as wind speed, wind direction, relative humidity and precipitation have an important role in the concentration of atmospheric dust. Dry environments with low relative humidity are ideal for the transport of aerosols. Results obtained from this research show the relationship between dust concentrations and meteorological parameters. Dust concentrations are highly correlated with relative humidity and wind speed. With all the data collected on site and the analysis of the meteorological parameters, models can be develop to predict the transport of particles as well as the concentration of contaminants at a specific point. These models were developed and are part of the results shown in this dissertation.

REPORT TO STATES, REGIONS, AND PROGRAM OFFICES DEMONSTRATING THE USE OF TIME SERIES ANALYSIS TO IDENTIFY NON-POINT SOURCE IMPACTS.

EPA Science Inventory

Land use change, and the implementation of best management practices to remedy the adverse effects of land use change, alter hydrologic patterns, contaminant loading and water quality in freshwater ecosystems. These changes are not constant over time, but vary in response to di...

USING REGIONAL EXPOSURE CRITERIA AND UPSTREAM REFERENCE DATA TO CHARACTERIZE SPATIAL AND TEMPORAL EXPOSURES TO CHEMICAL CONTAMINANTS

EPA Science Inventory

Analyses of biomarkers in fish were used to evaluate exposures among locations and across time. Two types of references were used for comparison, an upstream reference sample remote from known point sources and regional exposure criteria derived from a baseline of fish from refer...

Determining volume sensitive waters in Beaufort County, SC tidal creeks

Treesearch

Andrew Tweel; Denise Sanger; Anne Blair; John Leffler

2016-01-01

Non-point source pollution from stormwater runoff associated with large-scale land use changes threatens the integrity of ecologically and economically valuable estuarine ecosystems. Beaufort County, SC implemented volume-based stormwater regulations on the rationale that if volume discharge is controlled, contaminant loading will also be controlled.

Using Rare Earth Elements (REE) to determine wind-driven soil dispersal from a point source

USDA-ARS?s Scientific Manuscript database

Although erosion of soil by water is a predictably directional process, the erosion of soil by wind is determined by wind direction on an event-wise basis. The wind-driven dispersal patterns of chemical constituents including natural soil components and anthropogenic contaminants are not well under...

Multi-laboratory evaluations of the performance of Catellicoccus marimammalium PCR assays developed to target gull fecal sources

EPA Science Inventory

Here we report results from a multi-laboratory (n=11) evaluation of four different PCR methods targeting the 16S rRNA gene of Catellicoccus marimammalium used to detect fecal contamination from birds in coastal environments. The methods included conventional end-point PCR, a SYBR...

USING REGIONAL EXPOSURE CRITERIA AND UPSTREAM REFERENCE DATA TO CHARACTERIZE SPATIAL AND TEMPORAL EXPOSURES TO CHEMICAL CONTAMINANTS

EPA Science Inventory

Analyses of biomarkers in fish were used to evaluate exposures among locations and across time. Two types of references were used for comparison, an upstream reference sample remote from known point sources and regional exposure criteria derived from a basline of fish from refere...

Evaluation of sediment contamination by monoaromatic hydrocarbons in the coastal lagoons of Gulf of Saros, NE Aegean Sea.

PubMed

Ünlü, Selma; Alpar, Bedri

2017-05-15

The concentrations and distribution of monoaromatic hydrocarbons (benzene, toluene, ethyl benzene and the sum of m-, p- and o-, xylenes) were determined in the sediments of coastal lagoons of the Gulf of Saros, using a static headspace GC-MS. The total concentrations of BTEX compounds ranged from 368.5 to below detection limit 0.6μgkg -1 dw, with a mean value of 61.5μgkg -1 dw. The light aromatic fraction of m-, p-xylene was the most abundant compound (57.1% in average), and followed by toluene (38.1%)>ethylbenzene (4.1%)>o-xylene (2.5%)>benzene (1.1%). The factor analysis indicated that the levels and distribution of BTEX compounds depend on the type of contaminant source (mobile/point), absorbance of compounds in sediment, and mobility of benzene compound and degradation processes. Point sources are mainly related to agricultural facilities and port activities while the dispersion of compounds are related with their solubility, volatility and effect of sea/saline waters on lagoons. Copyright © 2017. Published by Elsevier Ltd.

Development of a mass balance model for estimating PCB export from the lower Fox River to Green Bay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Velleux, M.; Endicott, D.

A mass balance approach was used to model contaminant cycling in the lower Fox River from the DePere Dam to Green Bay. The objectives of this research were (1) to estimate present contaminant export from the Fox River to Green Bay, and (2) to quantify contaminant transport and fate pathways in the lower river for the study period. Specifically, a model describing the transport, fate, and export of chlorides, total suspended solids, total PCBs, and six PCB congeners for the lower Fox River was developed. Field data collected as part of the U.S. Environmental Protection Agency's Green Bay Mass Balancemore » Study were used to calibrate the model. Model results suggest that the transport of inplace pollutants significantly contributed to the cumulative export of total PCBs over this period. Estimated total PCB transport in the Fox River during 1989 increased 60% between the dam and river mouth due to the resuspension of lower river sediments. Total suspended solids and PCB predictions are most sensitive to particle transport parameters, particularly the settling and resuspension velocities. The significant components of the total PCB mass balance are import (loading over the DePere Dam), settling, resuspension, and export to Green Bay. Volatilization, porewater transport, and point source input were not significant to the mass balance. Present point source discharges to the river are not significant total PCB sources, collectively contributing less than 6 kg of PCB to the river during the mass balance period.« less

Estimating the Effectiveness of Health-Risk Communications with Propensity-Score Matching: Application to Arsenic Groundwater Contamination in Four US Locations

PubMed Central

Leidner, Andrew J.

2014-01-01

This paper provides a demonstration of propensity-score matching estimation methods to evaluate the effectiveness of health-risk communication efforts. This study develops a two-stage regression model to investigate household and respondent characteristics as they contribute to aversion behavior to reduce exposure to arsenic-contaminated groundwater. The aversion activity under study is a household-level point-of-use filtration device. Since the acquisition of arsenic contamination information and the engagement in an aversion activity may be codetermined, a two-stage propensity-score model is developed. In the first stage, the propensity for households to acquire arsenic contamination information is estimated. Then, the propensity scores are used to weight observations in a probit regression on the decision to avert the arsenic-related health risk. Of four potential sources of information, utility, media, friend, or others, information received from a friend appears to be the source of information most associated with aversion behavior. Other statistically significant covariates in the household's decision to avert contamination include reported household income, the presence of children in household, and region-level indicator variables. These findings are primarily illustrative and demonstrate the usefulness of propensity-score methods to estimate health-risk communication effectiveness. They may also be suggestive of areas for future research. PMID:25349622

Geochemical cartography as a tool for assessing the degree of soil contamination with heavy metals in Poland

NASA Astrophysics Data System (ADS)

Szymon Borkowski, Andrzej; Kwiatkowska-Malina, Jolanta

2016-04-01

Spatial disposition of chemical elements including heavy metals in the soil environment is a very important information during preparation of the thematic maps for the environmental protection and/or spatial planning. This knowledge is also essential for the earth's surface and soil's monitoring, designation of areas requiring improvement including remediation. The main source of anthropogenic pollution of soil with heavy metals are industry related to the mining coal and liquid fuels, mining and metallurgy, chemical industry, energy production, waste management, agriculture and transport. The geochemical maps as a kind of specific thematic maps made on the basis of datasets obtained from the Polish Geological Institute's resources allow to get to know the spatial distribution of different chemical elements including heavy metals in soil. The results of the research carried out by the Polish Geological Institute showed strong contamination in some regions in Poland mainly with arsenic, cadmium, lead and nickel. For this reason it was the point to prepare geochemical maps showing contamination of soil with heavy metals, and determine main sources of contamination and zones where heavy metals concentration was higher than acceptable contents. It was also presented a summary map of soil contamination with heavy metals. Additionally, location of highly contaminated zones was compiled with predominant in those areas types of arable soils and then results were thoroughly analyzed. This information can provide a base for further detailed studies on the soil contamination with heavy metals.

Regional Scale Simulations of Nitrate Leaching through Agricultural Soils of California

NASA Astrophysics Data System (ADS)

Diamantopoulos, E.; Walkinshaw, M.; O'Geen, A. T.; Harter, T.

2016-12-01

Nitrate is recognized as one of California's most widespread groundwater contaminants. As opposed to point sources, which are relative easily identifiable sources of contamination, non-point sources of nitrate are diffuse and linked with widespread use of fertilizers in agricultural soils. California's agricultural regions have an incredible diversity of soils that encompass a huge range of properties. This complicates studies dealing with nitrate risk assessment, since important biological and physicochemical processes appear at the first meters of the vadose zone. The objective of this study is to evaluate all agricultural soils in California according to their potentiality for nitrate leaching based on numerical simulations using the Richards equation. We conducted simulations for 6000 unique soil profiles (over 22000 soil horizons) taking into account the effect of climate, crop type, irrigation and fertilization management scenarios. The final goal of this study is to evaluate simple management methods in terms of reduced nitrate leaching. We estimated drainage rates of water under the root zone and nitrate concentrations in the drain water at the regional scale. We present maps for all agricultural soils in California which can be used for risk assessment studies. Finally, our results indicate that adoption of simple irrigation and fertilization methods may significantly reduce nitrate leaching in vulnerable regions.

Multi-hadron-state contamination in nucleon observables from chiral perturbation theory

NASA Astrophysics Data System (ADS)

Bär, Oliver

2018-03-01

Multi-particle states with additional pions are expected to be a non-negligible source of the excited-state contamination in lattice simulations at the physical point. It is shown that baryon chiral perturbation theory (ChPT) can be employed to calculate the contamination due to two-particle nucleon-pion states in various nucleon observables. Results to leading order are presented for the nucleon axial, tensor and scalar charge and three Mellin moments of parton distribution functions: the average quark momentum fraction, the helicity and the transversity moment. Taking into account experimental and phenomenological results for the charges and moments the impact of the nucleon-pionstates on lattice estimates for these observables can be estimated. The nucleon-pion-state contribution leads to an overestimation of all charges and moments obtained with the plateau method. The overestimation is at the 5-10% level for source-sink separations of about 2 fm. Existing lattice data is not in conflict with the ChPT predictions, but the comparison suggests that significantly larger source-sink separations are needed to compute the charges and moments with few-percent precision. Talk given at the 35th International Symposium on Lattice Field Theory, 18 - 24 June 2017, Granada, Spain.

Prevalence of organic and inorganic contaminants within a rapidly developing catchment

NASA Astrophysics Data System (ADS)

Njumbe, E. S.; Curtis, C. D.; Cooke, D. A.; Polya, D. A.; Wogelius, R. A.; Hughes, C.

2003-04-01

Industrialization rates in many developing countries typically outpace investment in water supply, sewage treatment and other waste water facilities. This is futher compounded by the absence of stringent land-use and waste disposal policies. The consequence of this has been contamination of land, surface water, and groundwater in such areas. Efforts to control and remediate these types of systems will rely on a thorough understanding of contaminant levels and mobility. Reliable data, however, is usually not available. Therefore this study was designed to acquire baseline data from a representative developing urban area in tropical west Africa. 43 water and 20 sediment/soil samples from streams, hand-dug wells, springs and deep boreholes within the city and surrounding areas of Douala in Cameroon were characterised. Analyses were aimed at obtaining information on the type and quantity of organic and inorganic contaminants present, and linking them to specific point and non-point sources. Results from gas chromatography (GC/FID) and gas chromatography/mass spectrometry analyses of total organic extracts (TOE) of water samples have revealed the presence of a wide range of organic compounds including phenols, polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs), phthalates, acids and aliphatic derivatives. Concentrations as high as 500 ng ml-1 were detected. These high levels of non-polar compounds measured in drinking water represent a clear health problem. Heavy metal concentrations in bulk alluvial sands and loamy soil have been determined by microwave assisted nitric acid digestion. Concentration ranges (in ppm of dry weight) for the important metals were: Cr, 3.2-84.2 ; Ni, 0.2-57.4 ; Zn, 2.1-92 ; Pb, 0.3-33 ; As, 0.081-9.4 ; Cu, 0.61-17.4 ; and Cd, 0-3.1. Point sources have been identified for several of the organic and inorganic compounds and this spatial information will be integrated with the chemical data to present an overview of environmental degradation within this system.

Occurrence and ecological risk assessment of emerging organic chemicals in urban rivers: Guangzhou as a case study in China.

PubMed

Peng, Feng-Jiao; Pan, Chang-Gui; Zhang, Min; Zhang, Nai-Sheng; Windfeld, Ronja; Salvito, Daniel; Selck, Henriette; Van den Brink, Paul J; Ying, Guang-Guo

2017-07-01

Urban rivers may receive contamination from various sources including point sources like domestic sewage and nonpoint sources (e.g., runoff), resulting in contamination with various chemicals. This study investigated the occurrence of emerging organic contaminants (3 endocrine disrupting compounds (EDCs), and 17 pharmaceuticals and personal care products (PPCPs)) in six urban rivers of a representative subtropical city, Guangzhou (southern China). Our results showed that EDCs and personal care products were frequently detected in the water phase and sediment phase. 4-nonylphenol (4-NP) was the most predominant compound with the highest concentration of 5050ng/L in the water phase and 14,400ng/g dry weight (dw) in the sediment. Generally, higher total concentrations of EDCs and PPCPs were detected in the four urban streams compared to the main stream Zhujiang River and the Liuxi River at the suburb area. A screening-level risk assessment showed that 4-nonylphenol and triclosan (TCS) pose potential risks to aquatic organisms in most sampling sites. For individual taxa, 4-NP may pose risks to various groups of aquatic organisms, while TCS only might pose high risks to algae. Higher contamination of EDCs and PPCPs was observed in rivers in urban area; 4-nonylphenol and triclosan showed RQs>1 in >70% of the reported area. Copyright © 2017 Elsevier B.V. All rights reserved.

Expert elicitation as a means to attribute 28 enteric pathogens to foodborne, waterborne, animal contact, and person-to-person transmission routes in Canada.

PubMed

Butler, Ainslie J; Thomas, M Kate; Pintar, Katarina D M

2015-04-01

Enteric illness contributes to a significant burden of illness in Canada and globally. Understanding its sources is a critical step in identifying and preventing health risks. Expert elicitation is a powerful tool, used previously, to obtain information about enteric illness source attribution where information is difficult or expensive to obtain. Thirty-one experts estimated transmission of 28 pathogens via major transmission routes (foodborne, waterborne, animal contact, person-to-person, and other) at the point of consumption. The elicitation consisted of a (snowball) recruitment phase; administration of a pre-survey to collect background information, an introductory webinar, an elicitation survey, a 1-day discussion, survey readministration, and a feedback exercise, and surveys were administered online. Experts were prompted to quantify changes in contamination at the point of entry into the kitchen versus point of consumption. Estimates were combined via triangular probability distributions, and medians and 90% credible-interval estimates were produced. Transmission was attributed primarily to food for Bacillus cereus, Clostridium perfringens, Cyclospora cayetanensis, Trichinella spp., all three Vibrio spp. categories explored, and Yersinia enterocolitica. Multisource pathogens (e.g., transmitted commonly through both water and food) such as Campylobacter spp., four Escherichia coli categories, Listeria monocytogenes, Salmonella spp., and Staphylococcus aureus were also estimated as mostly foodborne. Water was the primary pathway for Giardia spp. and Cryptosporidium spp., and person-to-person transmission dominated for six enteric viruses and Shigella spp. Consideration of the point of attribution highlighted the importance of food handling and cross-contamination in the transmission pathway. This study provides source attribution estimates of enteric illness for Canada, considering all possible transmission routes. Further research is necessary to improve our understanding of poorly characterized pathogens such as sapovirus and E. coli subgroups in Canada.

Understanding the contamination of food with mineral oil: the need for a confirmatory analytical and procedural approach.

PubMed

Spack, Lionel W; Leszczyk, Gabriela; Varela, Jesus; Simian, Hervé; Gude, Thomas; Stadler, Richard H

2017-06-01

The contamination of food by mineral oil hydrocarbons (MOHs) found in packaging is a long-running concern. A main source of MOHs in foods is the migration of mineral oil from recycled board into the packed food products. Consequently, the majority of food manufacturers have taken protective measures, e.g., by using virgin board instead of recycled fibres and, where feasible, introducing functional barriers to mitigate migration. Despite these protective measures, MOHs may still be observed in low amounts in certain food products, albeit due to different entry points across the food supply chain. In this study, we successfully apply gas chromatography coupled to mass spectrometry (GC-MS) to demonstrate, through marker compounds and the profile of the hydrocarbon response, the possible source of contamination using mainly chocolate and cereals as food matrices. The conventional liquid chromatography-one-dimensional GC coupled to a flame ionisation detector (LC-GC-FID) is a useful screening method, but in cases of positive samples it must be complemented by a confirmatory method such as, for example, GC-MS, allowing a verification of mineral oil contamination. The procedural approach proposed in this study entails profile analysis, marker identification, and interpretation and final quantification.

Effects of iodine in microbial control of dental treatment water.

PubMed

Puttaiah, Raghunath; Seibert, Jeff; Spears, Robert

2011-05-01

To determine the effects of low levels of iodine constantly present in the dental unit water system on microbial control of dental treatment water and biofilm control. This study used a dental unit water system simulator with eight dental unit waterline systems built to scale and function, each controlled via computer. Each of the eight units was operated independently, four units supplied with self-contained water reservoirs and four units supplied with municipal water. Four units were precleaned to remove biofilm buildup. The study had a well-balanced design with equal representation (variables) of presence/absence of biofilms, selfcontained reservoirs for introduction of treatment water, source water directly connected to municipal water source and iodinated cartridges within the self-contained reservoirs and between municipal water and dental unit. Point-of-use iodinated resin cartridges (IRC) were retrofitted proximal to handpiece and air/ water syringe tip lines in four units, and iodinated resin water cartridges (IRSWC) were fitted to the other four units at the source water output. Heterotrophic plate counts were performed at baseline and twice weekly for a period of 6 weeks. One representative waterline sample was taken from each group at baseline and end-of-study to analyze changes in biofilm status using scanning electron microscopy. Waterlines not previously contaminated with biofilms did not show organization of biofilm matrix in units equipped with IRSWC. Constantly present low levels of iodine, demonstrated some disruption of biofilms in waterlines already contaminated with mature biofilms. All groups showed contamination levels < 500 cfu/ml (colony forming units per milliliter) consistent with the CDC and ADA guidelines. In this 6 weeks study, IRSWC equipped waterlines showed disruption of established biofilms, controlled formation of new biofilms in clean lines and rendered the dental treatment water < 500 cfu/ml. Point-of-use iodinated resin cartridges were also effective in controlling contamination in the dental treatment water. Dental unit water systems that are in use get contaminated with microbes and biofilms in weeks of being put into use. These biofilms contaminate the treatment water thereby putting patients and staff at risk of infection by predominantly gram-negative microbes. Biofilms in the water systems must be cleaned periodically with a strong decontaminant and the dental treatment source water needs to be modified with a low-grade antimicrobial that can preserve the water quality yet safe to humans. In this translational research study, we evaluate the effects of elemental iodine dissolved in water flowing through an iodine containing cartridge in controlling biofilm and dental treatment water contamination using a dental unit water system simulator, prior to clinical utilization.

Integration of models of various types of aquifers for water quality management in the transboundary area of the Soča/Isonzo river basin (Slovenia/Italy).

PubMed

Vižintin, Goran; Ravbar, Nataša; Janež, Jože; Koren, Eva; Janež, Naško; Zini, Luca; Treu, Francesco; Petrič, Metka

2018-04-01

Due to intrinsic characteristics of aquifers groundwater frequently passes between various types of aquifers without hindrance. The complex connection of underground water paths enables flow regardless of administrative boundaries. This can cause problems in water resources management. Numerical modelling is an important tool for the understanding, interpretation and management of aquifers. Useful and reliable methods of numerical modelling differ with regard to the type of aquifer, but their connections in a single hydrodynamic model are rare. The purpose of this study was to connect different models into an integrated system that enables determination of water travel time from the point of contamination to water sources. The worst-case scenario is considered. The system was applied in the Soča/Isonzo basin, a transboundary river in Slovenia and Italy, where there is a complex contact of karst and intergranular aquifers and surface flows over bedrock with low permeability. Time cell models were first elaborated separately for individual hydrogeological units. These were the result of numerical hydrological modelling (intergranular aquifer and surface flow) or complex GIS analysis taking into account the vulnerability map and tracer tests results (karst aquifer). The obtained cellular models present the basis of a contamination early-warning system, since it allows an estimation when contaminants can be expected to appear, and in which water sources. The system proves that the contaminants spread rapidly through karst aquifers and via surface flows, and more slowly through intergranular aquifers. For this reason, karst water sources are more at risk from one-off contamination incidents, while water sources in intergranular aquifers are more at risk in cases of long-term contamination. The system that has been developed is the basis for a single system of protection, action and quality monitoring in the areas of complex aquifer systems within or on the borders of administrative units. Copyright © 2017 Elsevier B.V. All rights reserved.

Field Observations of Hydrodynamics, Sediment Transport, and Water and Sediment Quality in the Hudson-Raritan Estuary

NASA Astrophysics Data System (ADS)

Bruno, M. S.; Glenn, S.; Chant, R.; Rankin, K.; Korfiatis, G.; Dimou, N.; Creed, E.; Fullerton, B.; Pence, A.; Burke, P.; Haldeman, C.; Hires, R.; Hunter, E.

2002-12-01

The New York-New Jersey Harbor estuary system is of enormous ecological and economic importance to the region. The presence of toxic chemicals in the water and sediments results in reduced water quality, fisheries restrictions/advisories, and general adverse impacts to the estuarine ecosystem. The Port of New York and New Jersey is central to the economy of the region. However, in recent years, problems associated with the management of contaminated dredged material, including high costs and the lack of suitable disposal/use alternatives, have threatened to impact the volume of shipping in the Harbor. Sources of contaminants include atmospheric deposition, municipal and industrial wastewater treatment facilities, combined sewer and stormwater outfalls, and rainfall-induced runoff (non-point sources). In addition, Harbor sediments can act as a continuing source as they are re-suspended and moved throughout the system by both natural and man-made means. As part of the New Jersey Toxics Reduction Workplan, Stevens Institute of Technology and Rutgers University are conducting hydrodynamic, sediment transport, and water and suspended sediment quality measurements in Newark Bay, the Arthur Kill and the Kill van Kull. The goals of the project include: (1) collection of high resolution (event-driven and long-term) hydrodynamic, sediment transport and water and suspended sediment quality measurements for use in the assessment of the dominant physics of the system and in the development of a combined hydrodynamic-sediment transport-water/sediment quality model for the region. (2) identification of those tributaries to NY-NJ Harbor that are significant sources of the chemicals of concern, and evaluation of the importance of non-point sources and existing contaminated bottom sediments as sources of the chemicals of concern. (3) identification of point discharges that represent significant sources of the chemicals of concern. Observations were obtained over a two-year period, during 21 tributary flow "events", each having an approximate duration of 1 week. The measurement program included 3 fixed mooring stations and 5 shipboard locations. Each mooring consisted of an acoustic Doppler current profiler; a high-resolution pressure sensor; an OBS; a CTD; and a laser-based scatterometer. The ship-board measurements included vertical current profiles using a towed acoustic Doppler current profiler; CTD measurements; OBS measurements; suspended sediment concentration and particle size spectrum using a laser-based scatterometer; and chemical characterization of water and suspended sediment samples. The water and sediment quality measurements were obtained using a specially designed Trace Organics Platform Sampler. This sampler allowed for the measurement of low-level concentrations of PCBs (108 congeners), dioxins/furans, Pesticides, PAHs and metals (Hg, Cd, Pb). Preliminary analysis of the data has improved our understanding of the circulation and sediment transport patterns in this region of the estuary, including the influence of extreme tributary flow events, local winds, and anthropogenic effects such as port structures, vessels, and the navigation channels, and has identified the most highly contaminated reaches of the tributaries.

Measurement of Radiation Protection Factors for Contaminated Vehicles

DTIC Science & Technology

1999-03-01

sources, developed by the Aberdeen Test Center in the USA. Point sources of 6°Co are embedded in a blanket (on a 0.5 m grid) and draped over a vehicle...constructing a similar facility. Thus, a different approach is desired. This is achieved through the arrangement depicted in Figure 1. A rubber tube is draped ...Figure 1: Experimental set-up. A rubber tube was draped over the Grizzly at one foot intervals along the side ofthe Grizzly. Two motors (one shown at

Heavy metals in marine coastal sediments: assessing sources, fluxes, history and trends.

PubMed

Frignani, Mauro; Bellucci, Luca Giorgio

2004-01-01

Examples are presented from the Adriatic Sea, the Ligurian Sea and the Venice Lagoon to illustrate different approaches to the study of anthropogenic metals in marine coastal sediments. These examples refer to studies of areal distribution and transport mechanisms, individuation of the sources, sediment dating, chronology of the fluxes, present and past trends. In particular, some of the findings achieved in studying the Venice Lagoon are discussed from the point of view of anthropogenic changes both in sediment composition and contaminant fluxes.

Contaminant concentration versus flow velocity: drivers of biodegradation and microbial growth in groundwater model systems.

PubMed

Grösbacher, Michael; Eckert, Dominik; Cirpka, Olaf A; Griebler, Christian

2018-06-01

Aromatic hydrocarbons belong to the most abundant contaminants in groundwater systems. They can serve as carbon and energy source for a multitude of indigenous microorganisms. Predictions of contaminant biodegradation and microbial growth in contaminated aquifers are often vague because the parameters of microbial activity in the mathematical models used for predictions are typically derived from batch experiments, which don't represent conditions in the field. In order to improve our understanding of key drivers of natural attenuation and the accuracy of predictive models, we conducted comparative experiments in batch and sediment flow-through systems with varying concentrations of contaminant in the inflow and flow velocities applying the aerobic Pseudomonas putida strain F1 and the denitrifying Aromatoleum aromaticum strain EbN1. We followed toluene degradation and bacterial growth by measuring toluene and oxygen concentrations and by direct cell counts. In the sediment columns, the total amount of toluene degraded by P. putida F1 increased with increasing source concentration and flow velocity, while toluene removal efficiency gradually decreased. Results point at mass transfer limitation being an important process controlling toluene biodegradation that cannot be assessed with batch experiments. We also observed a decrease in the maximum specific growth rate with increasing source concentration and flow velocity. At low toluene concentrations, the efficiencies in carbon assimilation within the flow-through systems exceeded those in the batch systems. In all column experiments the number of attached cells plateaued after an initial growth phase indicating a specific "carrying capacity" depending on contaminant concentration and flow velocity. Moreover, in all cases, cells attached to the sediment dominated over those in suspension, and toluene degradation was performed practically by attached cells only. The observed effects of varying contaminant inflow concentration and flow velocity on biodegradation could be captured by a reactive-transport model. By monitoring both attached and suspended cells we could quantify the release of new-grown cells from the sediments to the mobile aqueous phase. Studying flow velocity and contaminant concentrations as key drivers of contaminant transformation in sediment flow-through microcosms improves our system understanding and eventually the prediction of microbial biodegradation at contaminated sites.

Use of the semipermeable membrane device (SPMD) to sample polycyclic aromatic hydrocarbon pollution in a lotic system

USGS Publications Warehouse

Lebo, Jon A.; Zajicek, James L.; Orazio, Carl E.; Petty, Jimmie D.; Huckins, James; Douglas, Ernest H.

1996-01-01

Relative concentrations of aqueous polycyclic aromatic hydrocarbons (PAH) were investigated in an urban creek. Samples were obtained at five sites within a 600-m segment of the creek that is critical habitat for an endangered species of fish. the sampling technique entailed immersion of semipermeable membrane devices (SPMDs) in the water for intervals as long as 64 d. SPMDs are passive, in situ, mtegrative samplers of bioavailable (truly dissolved) PAH and other hydrophobic organic contaminants. Two point sources of PAH to the 600-m segment of the creek were differentiated. Aqueous concentrations were found to wane dramatically over the relatively short section of the creek between the point sources. All samples were almost devoid of alkyl-substituted PAH, indicating that the ultimate sources were probably of pyrogenic nature.

Synoptic sampling and principal components analysis to identify sources of water and metals to an acid mine drainage stream.

PubMed

Byrne, Patrick; Runkel, Robert L; Walton-Day, Katherine

2017-07-01

Combining the synoptic mass balance approach with principal components analysis (PCA) can be an effective method for discretising the chemistry of inflows and source areas in watersheds where contamination is diffuse in nature and/or complicated by groundwater interactions. This paper presents a field-scale study in which synoptic sampling and PCA are employed in a mineralized watershed (Lion Creek, Colorado, USA) under low flow conditions to (i) quantify the impacts of mining activity on stream water quality; (ii) quantify the spatial pattern of constituent loading; and (iii) identify inflow sources most responsible for observed changes in stream chemistry and constituent loading. Several of the constituents investigated (Al, Cd, Cu, Fe, Mn, Zn) fail to meet chronic aquatic life standards along most of the study reach. The spatial pattern of constituent loading suggests four primary sources of contamination under low flow conditions. Three of these sources are associated with acidic (pH <3.1) seeps that enter along the left bank of Lion Creek. Investigation of inflow water (trace metal and major ion) chemistry using PCA suggests a hydraulic connection between many of the left bank inflows and mine water in the Minnesota Mine shaft located to the north-east of the river channel. In addition, water chemistry data during a rainfall-runoff event suggests the spatial pattern of constituent loading may be modified during rainfall due to dissolution of efflorescent salts or erosion of streamside tailings. These data point to the complexity of contaminant mobilisation processes and constituent loading in mining-affected watersheds but the combined synoptic sampling and PCA approach enables a conceptual model of contaminant dynamics to be developed to inform remediation.

Synoptic sampling and principal components analysis to identify sources of water and metals to an acid mine drainage stream

USGS Publications Warehouse

Byrne, Patrick; Runkel, Robert L.; Walton-Day, Katie

2017-01-01

Combining the synoptic mass balance approach with principal components analysis (PCA) can be an effective method for discretising the chemistry of inflows and source areas in watersheds where contamination is diffuse in nature and/or complicated by groundwater interactions. This paper presents a field-scale study in which synoptic sampling and PCA are employed in a mineralized watershed (Lion Creek, Colorado, USA) under low flow conditions to (i) quantify the impacts of mining activity on stream water quality; (ii) quantify the spatial pattern of constituent loading; and (iii) identify inflow sources most responsible for observed changes in stream chemistry and constituent loading. Several of the constituents investigated (Al, Cd, Cu, Fe, Mn, Zn) fail to meet chronic aquatic life standards along most of the study reach. The spatial pattern of constituent loading suggests four primary sources of contamination under low flow conditions. Three of these sources are associated with acidic (pH <3.1) seeps that enter along the left bank of Lion Creek. Investigation of inflow water (trace metal and major ion) chemistry using PCA suggests a hydraulic connection between many of the left bank inflows and mine water in the Minnesota Mine shaft located to the north-east of the river channel. In addition, water chemistry data during a rainfall-runoff event suggests the spatial pattern of constituent loading may be modified during rainfall due to dissolution of efflorescent salts or erosion of streamside tailings. These data point to the complexity of contaminant mobilisation processes and constituent loading in mining-affected watersheds but the combined synoptic sampling and PCA approach enables a conceptual model of contaminant dynamics to be developed to inform remediation.

Passive sampling methods for contaminated sediments: Risk assessment and management

PubMed Central

Greenberg, Marc S; Chapman, Peter M; Allan, Ian J; Anderson, Kim A; Apitz, Sabine E; Beegan, Chris; Bridges, Todd S; Brown, Steve S; Cargill, John G; McCulloch, Megan C; Menzie, Charles A; Shine, James P; Parkerton, Thomas F

2014-01-01

This paper details how activity-based passive sampling methods (PSMs), which provide information on bioavailability in terms of freely dissolved contaminant concentrations (Cfree), can be used to better inform risk management decision making at multiple points in the process of assessing and managing contaminated sediment sites. PSMs can increase certainty in site investigation and management, because Cfree is a better predictor of bioavailability than total bulk sediment concentration (Ctotal) for 4 key endpoints included in conceptual site models (benthic organism toxicity, bioaccumulation, sediment flux, and water column exposures). The use of passive sampling devices (PSDs) presents challenges with respect to representative sampling for estimating average concentrations and other metrics relevant for exposure and risk assessment. These challenges can be addressed by designing studies that account for sources of variation associated with PSMs and considering appropriate spatial scales to meet study objectives. Possible applications of PSMs include: quantifying spatial and temporal trends in bioavailable contaminants, identifying and evaluating contaminant source contributions, calibrating site-specific models, and, improving weight-of-evidence based decision frameworks. PSM data can be used to assist in delineating sediment management zones based on likelihood of exposure effects, monitor remedy effectiveness, and, evaluate risk reduction after sediment treatment, disposal, or beneficial reuse after management actions. Examples are provided illustrating why PSMs and freely dissolved contaminant concentrations (Cfree) should be incorporated into contaminated sediment investigations and study designs to better focus on and understand contaminant bioavailability, more accurately estimate exposure to sediment-associated contaminants, and better inform risk management decisions. Research and communication needs for encouraging broader use are discussed. Integr Environ Assess Manag 2014;10:224–236. © 2014 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of SETAC. PMID:24343931

Method for the Collection, Gravimetric and Chemical Analysis of Nonvolatile Residue (NVR) on Surfaces

NASA Technical Reports Server (NTRS)

Gordon, Keith; Rutherford, Gugu; Aranda, Denisse

2017-01-01

Nonvolatile residue (NVR), sometimes referred to as molecular contamination is the term used for the total composition of the inorganic and high boiling point organic components in particulates and molecular films deposited on critical surfaces surrounding space structures, with the particulate and NVR contamination originating primarily from pre-launch operations. The "nonvolatile" suggestion from the terminology NVR implies that the collected residue will not experience much loss under ambient conditions. NVR has been shown to have a dramatic impact on the ability to perform optical measurements from platforms based in space. Such contaminants can be detected early by the controlled application of various detection techniques and contamination analyses. Contamination analyses are the techniques used to determine if materials, components, and subsystems can be expected to meet the performance requirements of a system. Of particular concern is the quantity of NVR contaminants that might be deposited on critical payload surfaces from these sources. Subsequent chemical analysis of the contaminant samples by infrared spectroscopy and gas chromatography mass spectrometry identifies the components, gives semi-quantitative estimates of contaminant thickness, indicates possible sources of the NVR, and provides guidance for effective cleanup procedures. In this report, a method for the collection and determination of the mass of NVR was generated by the authors at NASA Langley Research Center. This report describes the method developed and implemented for collecting NVR contaminants, and procedures for gravimetric and chemical analysis of the residue obtained. The result of this NVR analysis collaboration will help pave the way for Langley's ability to certify flight hardware outgassing requirements in support of flight projects such as Stratospheric Aerosol and Gas Experiment III (SAGE III), Clouds and the Earth's Radiant Energy System (CERES), Materials International Space Station Experiment - X (MISSE-X), and Doppler Aerosol Wind Lidar (DAWN).

Positive matrix factorization as source apportionment of soil lead and cadmium around a battery plant (Changxing County, China).

PubMed

Xue, Jian-long; Zhi, Yu-you; Yang, Li-ping; Shi, Jia-chun; Zeng, Ling-zao; Wu, Lao-sheng

2014-06-01

Chemical compositions of soil samples are multivariate in nature and provide datasets suitable for the application of multivariate factor analytical techniques. One of the analytical techniques, the positive matrix factorization (PMF), uses a weighted least square by fitting the data matrix to determine the weights of the sources based on the error estimates of each data point. In this research, PMF was employed to apportion the sources of heavy metals in 104 soil samples taken within a 1-km radius of a lead battery plant contaminated site in Changxing County, Zhejiang Province, China. The site is heavily contaminated with high concentrations of lead (Pb) and cadmium (Cd). PMF successfully partitioned the variances into sources related to soil background, agronomic practices, and the lead battery plants combined with a geostatistical approach. It was estimated that the lead battery plants and the agronomic practices contributed 55.37 and 29.28%, respectively, for soil Pb of the total source. Soil Cd mainly came from the lead battery plants (65.92%), followed by the agronomic practices (21.65%), and soil parent materials (12.43%). This research indicates that PMF combined with geostatistics is a useful tool for source identification and apportionment.

Land use change detection with LANDSAT-2 data for monitoring and predicting regional water quality degradation. [Arkansas

NASA Technical Reports Server (NTRS)

Macdonald, H.; Steele, K. (Principal Investigator); Waite, W.; Rice, R.; Shinn, M.; Dillard, T.; Petersen, C.

1977-01-01

The author has identified the following significant results. Comparison between LANDSAT 1 and 2 imagery of Arkansas provided evidence of significant land use changes during the 1972-75 time period. Analysis of Arkansas historical water quality information has shown conclusively that whereas point source pollution generally can be detected by use of water quality data collected by state and federal agencies, sampling methodologies for nonpoint source contamination attributable to surface runoff are totally inadequate. The expensive undertaking of monitoring all nonpoint sources for numerous watersheds can be lessened by implementing LANDSAT change detection analyses.

A source of PCB contamination in modified high-volume air samplers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Basu, I.; O'Dell, J.M.; Arnold, K.

2000-02-01

Modified Anderson High Volume (Hi-Vol) air samplers are widely used for the collection of semi-volatile organic compounds (such as PCBs) from air. The foam gasket near the main air flow path in these samplers can become contaminated with PCBs if the sampler or the gasket is stored at a location with high indoor air PCB levels. Once the gasket is contaminated, it releases PCBs back into the air stream during sampling, and as a result, incorrectly high air PCB concentrations are measured. This paper presents data demonstrating this contamination problem using measurements from two Integrated Atmospheric Deposition Network sites: onemore » at Sleeping Bear Dunes on Lake Michigan and the other at Point Petre on Lake Ontario. The authors recommend that these gaskets be replaced by Teflon tape and that the storage history of each sampler be carefully tracked.« less

Integrated assessment of sources, chemical stressors and stream quality along a groundwater fed stream system

NASA Astrophysics Data System (ADS)

Løgstrup Bjerg, Poul; Sonne, Anne T.; Rønde, Vinni; McKnight, Ursula S.

2016-04-01

Streams are impacted by significant contamination at the catchment scale, as they are often locations of multiple chemical stressor inputs. The European Water Framework Directive requires EU member states to ensure good chemical and ecological status of surface water bodies by 2027. This requires monitoring of stream water quality, comparison with environmental quality standards (EQS) and assessment of ecological status. However, the achievement of good status of stream water also requires a strong focus on contaminant sources, pathways and links to stream water impacts, so source management and remedial measures can be implemented. Fate and impacts of different contaminant groups are governed by different processes and are dependent on the origin (geogenic, anthropogenic), source type (point or diffuse) and pathway of the contaminant. To address this issue, we identified contaminant sources and chemical stressors on a groundwater-fed stream to quantify the contaminant discharges, link the chemical impact and stream water quality and assess the main chemical risk drivers in the stream system potentially driving ecological impact. The study was conducted in the 8 m wide Grindsted stream (Denmark) along a 16 km stream stretch that is potentially impacted by two contaminated sites (Grindsted Factory site, Grindsted Landfill), fish farms, waste water discharges, and diffuse sources from agriculture and urban areas. Water samples from the stream and the hyporheic zone as well as bed sediment samples were collected during three campaigns in 2012 and 2014. Data for xenobiotic organic groundwater contaminants, pesticides, heavy metals, general water chemistry, physical conditions and stream flow were collected. The measured chemical concentrations were converted to toxic units (TU) based on the 48h acute toxicity tests with D. magna. The results show a substantial impact of the Grindsted Factory site at a specific stretch of the stream. The groundwater plume caused elevated concentrations of chlorinated ethenes, benzene and site specific pharmaceuticals in both the hyporheic zone and the stream water. Observed stream water vinyl chloride concentrations (up to 6 μg/L) are far above the Danish EQS (0.05 μg/L) for several km downstream of the discharge area. For heavy metals, comparison with EQS in stream water, the hyporheic zone and streambed showed concentrations around or above the threshold values for barium, copper, lead, nickel and zinc. The calculated TU was generally similar along the stream, but for arsenic and nickel higher values were observed where the groundwater plume discharges into the stream. Also, log TU sum values for organic contaminants were elevated in both the hyporheic zone and stream. Thus, the overall chemical stress in the main discharge area is much higher than upstream, while it gradually decreases downstream. In conclusion, this work clearly shows that groundwater contaminant plumes can impact stream water quality significantly in discharge areas, and extend far downstream. A surprisingly high impact of heavy metals with diffuse and/or biogenic origin on stream quality was identified. This work highlights the importance of a holistic assessment of stream water quality to identify and quantify the main contaminant sources and resulting chemical stream stressors leading to potential ecological impacts.

Drinking water incidents due to chemical contamination in England and Wales, 2006-2008.

PubMed

Paranthaman, Karthikeyan; Harrison, Henrietta

2010-12-01

Contamination of drinking water by microbiological and chemical agents can lead to adverse health effects. In England and Wales, the Chemicals Hazards and Poisons Division (CHaPD) of the Health Protection Agency provides expert advice on the consequences to public health of chemical contamination incidents affecting drinking water. In this study, we extracted data from the National Database on the type and nature of drinking water contamination events reported to the CHaPD between 2006 and 2008. Eighty-two incidents with confirmed chemical contamination were identified. Among the 70 incidents where data was available, 40% (28/70) of incidents related to contamination of drinking water provided by private suppliers, 31% (22/70) were due to contamination occurring close to the point of consumption (i.e. near consumer) and 29% (20/70) related to incidents where public water supplies were identified as the contaminated source. For the majority of incidents, little or no information was available on the critical exposure variables such as duration of contamination and actual or estimates of the population affected. Reassuringly, the levels of exposure in most incidents were considered unlikely to cause serious immediate or long term ill health effects. Recording of exposure data for reported contamination incidents needs to be improved.

Rural drinking water at supply and household levels: quality and management.

PubMed

Hoque, Bilqis A; Hallman, Kelly; Levy, Jason; Bouis, Howarth; Ali, Nahid; Khan, Feroze; Khanam, Sufia; Kabir, Mamun; Hossain, Sanower; Shah Alam, Mohammad

2006-09-01

Access to safe drinking water has been an important national goal in Bangladesh and other developing countries. While Bangladesh has almost achieved accepted bacteriological drinking water standards for water supply, high rates of diarrheal disease morbidity indicate that pathogen transmission continues through water supply chain (and other modes). This paper investigates the association between water quality and selected management practices by users at both the supply and household levels in rural Bangladesh. Two hundred and seventy tube-well water samples and 300 water samples from household storage containers were tested for fecal coliform (FC) concentrations over three surveys (during different seasons). The tube-well water samples were tested for arsenic concentration during the first survey. Overall, the FC was low (the median value ranged from 0 to 4 cfu/100ml) in water at the supply point (tube-well water samples) but significantly higher in water samples stored in households. At the supply point, 61% of tube-well water samples met the Bangladesh and WHO standards of FC; however, only 37% of stored water samples met the standards during the first survey. When arsenic contamination was also taken into account, only 52% of the samples met both the minimum microbiological and arsenic content standards of safety. The contamination rate for water samples from covered household storage containers was significantly lower than that of uncovered containers. The rate of water contamination in storage containers was highest during the February-May period. It is shown that safe drinking water was achieved by a combination of a protected and high quality source at the initial point and maintaining quality from the initial supply (source) point through to final consumption. It is recommended that the government and other relevant actors in Bangladesh establish a comprehensive drinking water system that integrates water supply, quality, handling and related educational programs in order to ensure the safety of drinking water supplies.

A summary of total mercury concentrations in flora and fauna near common contaminant sources in the Gulf of Mexico.

PubMed

Lewis, M; Chancy, C

2008-02-01

Total mercury concentrations are summarized for environmental media and biota collected from near-coastal areas, several impacted by contaminant sources common to the Gulf of Mexico. Water, sediment, fish, blue crabs, oysters, clams, mussels, periphyton and seagrasses were collected during 1993-2002 from targeted areas affected by point and non-point source contaminants. Mean concentrations in water and sediment were 0.02 (+/-1 standard deviation=0.06) microg l(-1) and 96.3 (230.8) ng g(-1) dry wt, respectively. Mean total mercury concentrations in fish, blue crabs, brackish clams and mussels were significantly greater than those in sediment, seagrass, colonized periphyton and oysters. Concentrations (ng g(-1) dry wt) averaged 23.1 (two seagrass species), 220.1 (oysters), 287.8 (colonized periphyton), 604.0 (four species of freshwater mussels), 772.4 (brackish clam), 857.9 (blue crabs) and 933.1 (nine fish species). Spatial, intraspecific and interspecific variability in results limited most generalizations concerning the relative mercury contributions of different stressor types. However, concentrations were significantly greater for some biota collected from areas receiving wastewater discharges and golf course runoff (fish), agricultural runoff (oysters) and urban stormwater runoff (colonized periphyton and sediment). Marine water quality criteria and proposed sediment quality guidelines were exceeded in 1-12% of total samples. At least one seafood consumption guideline, criteria or screening value were exceeded in edible tissues of blue crabs (6% total samples) and nine fish species (8-33% total samples) but all residues were less than the US Federal Drug Administration action limit of 1.0 ppm and the few reported toxic effect concentrations available for the targeted biota.

Source Apportionment and Risk Assessment of Emerging Contaminants: An Approach of Pharmaco-Signature in Water Systems

PubMed Central

Jiang, Jheng Jie; Lee, Chon Lin; Fang, Meng Der; Boyd, Kenneth G.; Gibb, Stuart W.

2015-01-01

This paper presents a methodology based on multivariate data analysis for characterizing potential source contributions of emerging contaminants (ECs) detected in 26 river water samples across multi-scape regions during dry and wet seasons. Based on this methodology, we unveil an approach toward potential source contributions of ECs, a concept we refer to as the “Pharmaco-signature.” Exploratory analysis of data points has been carried out by unsupervised pattern recognition (hierarchical cluster analysis, HCA) and receptor model (principal component analysis-multiple linear regression, PCA-MLR) in an attempt to demonstrate significant source contributions of ECs in different land-use zone. Robust cluster solutions grouped the database according to different EC profiles. PCA-MLR identified that 58.9% of the mean summed ECs were contributed by domestic impact, 9.7% by antibiotics application, and 31.4% by drug abuse. Diclofenac, ibuprofen, codeine, ampicillin, tetracycline, and erythromycin-H2O have significant pollution risk quotients (RQ>1), indicating potentially high risk to aquatic organisms in Taiwan. PMID:25874375

Transplantation of epiphytic bioaccumulators (Tillandsia capillaris) for high spatial resolution biomonitoring of trace elements and point sources deconvolution in a complex mining/smelting urban context

NASA Astrophysics Data System (ADS)

Goix, Sylvaine; Resongles, Eléonore; Point, David; Oliva, Priscia; Duprey, Jean Louis; de la Galvez, Erika; Ugarte, Lincy; Huayta, Carlos; Prunier, Jonathan; Zouiten, Cyril; Gardon, Jacques

2013-12-01

Monitoring atmospheric trace elements (TE) levels and tracing their source origin is essential for exposure assessment and human health studies. Epiphytic Tillandsia capillaris plants were used as bioaccumulator of TE in a complex polymetallic mining/smelting urban context (Oruro, Bolivia). Specimens collected from a pristine reference site were transplanted at a high spatial resolution (˜1 sample/km2) throughout the urban area. About twenty-seven elements were measured after a 4-month exposure, also providing new information values for reference material BCR482. Statistical power analysis for this biomonitoring mapping approach against classical aerosols surveys performed on the same site showed the better aptitude of T. Capillaris to detect geographical trend, and to deconvolute multiple contamination sources using geostatistical principal component analysis. Transplanted specimens in the vicinity of the mining and smelting areas were characterized by extreme TE accumulation (Sn > Ag > Sb > Pb > Cd > As > W > Cu > Zn). Three contamination sources were identified: mining (Ag, Pb, Sb), smelting (As, Sn) and road traffic (Zn) emissions, confirming results of previous aerosol survey.

Baseline ecological risk assessment of the Calcasieu Estuary, Louisiana: 3. An evaluation of the risks to benthic invertebrates associated with exposure to contaminated sediments

USGS Publications Warehouse

MacDonald, Donald D.; Ingersoll, Christopher G.; Kemble, Nile E.; Smorong, Dawn E.; Sinclair, Jesse A.; Lindskoog, Rebekka; Gaston, Gary; Sanger, Denise; Carr, R. Scott; Biedenbach, James; Gouguet, Ron; Kern, John; Shortelle, Ann; Field, L. Jay; Meyer, John

2011-01-01

The sediments in the Calcasieu Estuary are contaminated with a wide variety of chemicals of potential concern (COPCs), including heavy metals, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, phthalates, chlorinated benzenes, and polychlorinated dibenzo-p-dioxins and dibenzofurans. The sources of these COPCs include both point and non-point source discharges. As part of a baseline ecological risk assessment, the risks to benthic invertebrates posed by exposure to sediment-associated COPCs were assessed using five lines of evidence, including whole-sediment chemistry, pore-water chemistry, whole-sediment toxicity, pore-water toxicity, and benthic invertebrate community structure. The results of this assessment indicated that exposure to whole sediments and/or pore water from the Calcasieu Estuary generally posed low risks to benthic invertebrate communities (i.e., risks were classified as low for 68% of the sampling locations investigated). However, incremental risks to benthic invertebrates (i.e., compared with those associated with exposure to conditions in reference areas) were indicated for 32% of the sampling locations within the estuary. Of the three areas of concern (AOCs) investigated, the risks to benthic invertebrates were highest in the Bayou d'Inde AOC; risks were generally lower in the Upper Calcasieu River AOC and Middle Calcasieu River AOC. The areas showing the highest risks to sediment-dwelling organisms were generally located in the vicinity of point source discharges of COPCs. These results provided risk managers with the information required to make decisions regarding the need for remedial actions at the site.

Occurrence and potential health risk of Cryptosporidium and Giardia in different water catchments in Belgium.

PubMed

Ehsan, Amimul; Geurden, Thomas; Casaert, Stijn; Paulussen, Jef; De Coster, Lut; Schoemaker, Toon; Chalmers, Rachel; Grit, Grietje; Vercruysse, Jozef; Claerebout, Edwin

2015-02-01

Human wastewater and livestock can contribute to contamination of surface water with Cryptosporidium and Giardia. In countries where a substantial proportion of drinking water is produced from surface water, e.g., Belgium, this poses a constant threat on drinking water safety. Our objective was to monitor the presence of Cryptosporidium and Giardia in different water catchment sites in Belgium and to discriminate between (oo)cysts from human or animal origin using genotyping. Monthly samples were collected from raw water and purified drinking water at four catchment sites. Cryptosporidium and Giardia were detected using USEPA method 1623 and positive samples were genotyped. No contamination was found in purified water at any site. In three catchments, only low numbers of (oo)cysts were recovered from raw water samples (<1/liter), but raw water samples from one catchment site were frequently contaminated with Giardia (92 %) and Cryptosporidium (96 %), especially in winter and spring. Genotyping of Giardia in 38 water samples identified the presence of Giardia duodenalis assemblage AI, AII, BIV, BIV-like, and E. Cryptosporidium andersoni, Cryptosporidium suis, Cryptosporidium horse genotype, Cryptosporidium parvum, and Cryptosporidium hominis were detected. The genotyping results suggest that agriculture may be a more important source of surface water contamination than human waste in this catchment. In catchment sites with contaminated surface water, such as the Blankaart, continuous monitoring of treated water for the presence of Cryptosporidium and Giardia would be justified and (point) sources of surface water contamination should be identified.

Assessing ongoing sources of dissolved-phase polychlorinated biphenyls in a contaminated stream

USGS Publications Warehouse

Dang, Viet D.; Walters, David M.; Lee, Cindy M.

2013-01-01

Few studies assess the potential of ongoing sources of “fresh” polychlorinated biphenyls (PCBs) to aquatic systems when direct discharge to the environment has been eliminated. In the present study, the authors used single-layered, low-density polyethylene samplers (PEs) to measure total PCB concentrations, congener profiles, and enantiomeric fractions (EFs) in a contaminated stream and to provide multiple lines of evidence for assessing ongoing inputs of PCB. Concentrations were well above background levels that have been monitored for years. Concentrations significantly increased with distance, the farthest downstream PE concentrations being almost five times greater than those at 79 m downstream of a historical point source. The PCBs in the PEs at 79 m downstream of the contamination source were dominated by low KOW congeners, similar to those in the mixture of Aroclors 1016 and 1254 (4:1 v/v) historically released from the former capacitor manufacturer. The only two chiral congeners detected in the PEs downstream were PCBs 91 and 95. The EF values were nonracemic for PCB 91, while the values were either racemic or near racemic for PCB 95. Increased PCB concentrations with distance and a congener composition of predominantly low-weight congeners in the PEs at 79 m downstream of the plant site suggested an ongoing PCB source from the plant site. Chiral signatures suggested aerobic biotransformation of dissolved PCBs but did not shed any light on possible ongoing PCB inputs.

Appraisal of data for ground-water quality in Nebraska

USGS Publications Warehouse

Engberg, R.A.

1984-01-01

This report summarizes existing data for groundwater quality in Nebraska and indicates their adequacy as a data base. Analyses have been made of water from nearly 10,000 wells by 8 agencies. Those analyses that meet reliability criteria have been aggregated by geologic source of water into four principal aquifer groupings--Holocene-Pleistocene aquifers, Tertiary aquifers, Mesozoic aquifers, and Paleozoic aquifers. For each aquifer grouping, data for specific conductance and 24 constituents in the water are summarized statistically. Also, diagrams are presented showing differences in statistical parameters, or in chemical composition, of water from the different aquifer groupings. Additionally, for each grouping except Paleozoic aquifers, maps show ranges in concentration of dissolved solids, calcium, alkalinity, and sulfate. In areas where data are insufficient to delimit, ranges in concentration also are shown on the maps. Point-source contamination has been identified at 41 locations and nonpoint-source contamination in 3 areas, namely, the central Platte Valley, Holt County, and Boyd County. Potential for nonpoint-source contamination exists in 10 major areas, which together comprise more than one-third of the State. Existing data are mostly from specific projects having limited areas and objectives. Consequently, a lack of data exists for other areas and for certain geologic units, particularly the Mesozoic and Paleozoic aquifers. Specific data needs for each of the four principal aquifer groupings are indicated in a matrix table.

Calm Multi-Baryon Operators

NASA Astrophysics Data System (ADS)

Berkowitz, Evan; Nicholson, Amy; Chang, Chia Cheng; Rinaldi, Enrico; Clark, M. A.; Joó, Bálint; Kurth, Thorsten; Vranas, Pavlos; Walker-Loud, André

2018-03-01

There are many outstanding problems in nuclear physics which require input and guidance from lattice QCD calculations of few baryons systems. However, these calculations suffer from an exponentially bad signal-to-noise problem which has prevented a controlled extrapolation to the physical point. The variational method has been applied very successfully to two-meson systems, allowing for the extraction of the two-meson states very early in Euclidean time through the use of improved single hadron operators. The sheer numerical cost of using the same techniques in two-baryon systems has so far been prohibitive. We present an alternate strategy which offers some of the same advantages as the variational method while being significantly less numerically expensive. We first use the Matrix Prony method to form an optimal linear combination of single baryon interpolating fields generated from the same source and different sink interpolating fields. Very early in Euclidean time this optimal linear combination is numerically free of excited state contamination, so we coin it a calm baryon. This calm baryon operator is then used in the construction of the two-baryon correlation functions. To test this method, we perform calculations on the WM/JLab iso-clover gauge configurations at the SU(3) flavor symmetric point with mπ 800 MeV — the same configurations we have previously used for the calculation of two-nucleon correlation functions. We observe the calm baryon significantly removes the excited state contamination from the two-nucleon correlation function to as early a time as the single-nucleon is improved, provided non-local (displaced nucleon) sources are used. For the local two-nucleon correlation function (where both nucleons are created from the same space-time location) there is still improvement, but there is significant excited state contamination in the region the single calm baryon displays no excited state contamination.

Assessment of heavy metal contamination in the sediments from the Yellow River Wetland National Nature Reserve (the Sanmenxia section), China.

PubMed

Cheng, Qingli; Wang, Ruiling; Huang, Wenhai; Wang, Wenlin; Li, Xudong

2015-06-01

The Yellow River Wetland National Nature Reserve (the Sanmenxia section) is an important area of the Yellow River for two important hydrologic gauging stations: the Sanmenxia reservoir and the Xiaolangdi reservoir. Seven sites along the section were selected: Jiziling, Dinghuwan, Houdi, Canglonghu, Shangcun, Wangguan, and Nancun. After the microwave digestion with aqua regia, concentrations of Cu, Pb, Cd, Cr, Zn, and Mn in the sediments were analyzed by flame atomic absorption spectrometry with air-acetylene flame. The results showed that all the concentrations of Cr detected were from the lithogenic source, and 63 % Mn, 48 % Pb, 41 % Cu, 20 % Cd, and 12 % Zn were from the anthropogenic source. The values of the index of geo-accumulation pointed out that there was moderate contamination of Mn at the Dinghuwan (1.04) and Houdi (1.00) sites (class 2), while the modified degree of contamination denoted that the contamination at the Houdi site (2.02) was moderate, nil to very low at the Nancun and Shangcun sites and low at the other sites, consisting with the tendency of pollution load index. For metal toxicity, the sediment pollution index indicated that the sediments of the Canglonghu site were low polluted, that of the Houdi site is nearly slightly contaminated, and those of others were natural and uncontaminated. It was vital to evaluate the degree of contamination with individual and overall elements and even with the metal toxicity. Cu, Pb, and Mn contaminations were aggravated in the Sanmenxia section, and there maybe was one of the main anthropogenic sources of these metals along the Yellow River. The findings were expected to update the current status of the heavy metal pollution in the Sanmenxia section as well as to create awareness concerning the sound condition of the whole reaches of the Yellow River.

Temporal and spatial distributions of contaminants in sediments of Santa Monica Bay, California

USGS Publications Warehouse

Bay, S.M.; Zeng, E.Y.; Lorenson, T.D.; Tran, K.; Alexander, Corrine

2003-01-01

Contaminant inputs from wastewater discharge, a major source of contamination to Santa Monica Bay (SMB), have declined drastically during the last three decades as a result of improved treatment processes and better source control. To assess the concomitant temporal changes in the SMB sediments, a study was initiated in June 1997, in which 25 box cores were collected using a stratified random sampling design. Five sediment strata corresponding to the time intervals of 1890-1920, 1932-1963, 1965-1979, 1979-1989, and 1989-1997 were identified using 210Pb dating techniques. Samples from each stratum were analyzed for metals, 1,1,1-Trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) and its metabolites (DDTs), polychlorinated biphenyls (PCBs), and total organic carbon (TOC). Samples from the 1965-1979, 1979-1989, and 1989-1997 strata were also analyzed for polycyclic aromatic hydrocarbons (PAHs) and linear alkylbenzenes (LABs). Sediment metal concentrations increased from 1890-1979 and were similar during the time intervals of 1965-1979, 1979-1989, and 1989-1997, although the mass emissions of trace metals from sewage inputs declined substantially during the same time period. Trace organic contamination in SMB was generally highest in sediments corresponding to deposition during the years of 1965-1979 or 1979-1989 and showed a decline in concentration in the 1989-1997 stratum. Temporal trends of contamination were greatest in sediments collected from areas near the Hyperion Treatment Plant (HTP) outfall system and on the slope of Redondo Canyon. The highest contaminant concentrations were present in sediments near the HTP 7-mile outfall in the 1965-1979 stratum. Elevated trace metal and organic concentrations were still present in the 1989-1997 stratum of most stations, suggesting that sediment contaminants have moved vertically in the sediment column since sludge discharges from the 7-mile outfall (a dominant source of contamination to the bay) ceased in 1987. The widespread distributions of DDTs and PCBs in SMB and highly confined distribution of LABs around the HTP outfall system were indicative of a dispersal mechanism remobilizing historically deposited contaminants to areas relatively remote from the point of discharge. ?? 2003 Elsevier Science Ltd. All rights reserved.

Storm water runoff for the Y-12 Plant and selected parking lots

DOE Office of Scientific and Technical Information (OSTI.GOV)

Collins, E.T.

1996-01-01

A comparison of storm water runoff from the Y-12 Plant and selected employee vehicle parking lots to various industry data is provided in this document. This work is an outgrowth of and part of the continuing Non-Point Source Pollution Elimination Project that was initiated in the late 1980s. This project seeks to identify area pollution sources and remediate these areas through the Resource Conservation and Recovery Act/Comprehensive Environmental Response, Compensation, and Liability Act (RCRA/CERCLA) process as managed by the Environmental Restoration Organization staff. This work is also driven by the Clean Water Act Section 402(p) which, in part, deals withmore » establishing a National Pollutant Discharge Elimination System (NPDES) permit for storm water discharges. Storm water data from events occurring in 1988 through 1991 were analyzed in two reports: Feasibility Study for the Best Management Practices to Control Area Source Pollution Derived from Parking Lots at the DOE Y-12 Plant, September 1992, and Feasibility Study of Best Management Practices for Non-Point Source Pollution Control at the Oak Ridge Y-12 Plant, February 1993. These data consisted of analysis of outfalls discharging to upper East Fork Poplar Creek (EFPC) within the confines of the Y-12 Plant (see Appendixes D and E). These reports identified the major characteristics of concern as copper, iron, lead, manganese, mercury, nitrate (as nitrogen), zinc, biological oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), fecal coliform, and aluminum. Specific sources of these contaminants were not identifiable because flows upstream of outfalls were not sampled. In general, many of these contaminants were a concern in many outfalls. Therefore, separate sampling exercises were executed to assist in identifying (or eliminating) specific suspected sources as areas of concern.« less

Bacteriophages in food fermentations: new frontiers in a continuous arms race.

PubMed

Samson, Julie E; Moineau, Sylvain

2013-01-01

Phage contamination represents an important risk to any process requiring bacterial growth, particularly in the biotechnology and food industries. The presence of unwanted phages may lead to manufacturing delays, lower quality product, or, in the worst cases, total production loss. Thus, constant phage monitoring and stringent application of the appropriate control measures are indispensable. In fact, a systematic preventive approach to phage contamination [phage analysis and critical control points (PACCP)] should be put in place. In this review, sources of phage contamination and novel phage detection methods are described, with an emphasis on bacterial viruses that infect lactic acid bacteria used in food fermentations. Recent discoveries related to antiphage systems that are changing our views on phage-host interactions are highlighted. Finally, future directions are also discussed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lewis, J.C.; Hochreitner, J.J.

Investigations of potential sources of groundwater contamination conducted by various regulatory agencies and consultants at four industrial sites in Logan Township, New Jersey found groundwater contamination at all four sites and at properties adjoining two of the sites. The four sites directly overlie the Potomac-Raritan-Magothy aquifer system, the Township's sole source of potable water. One site was a waste-oil processing and storage facility. The major source of groundwater contamination at the site is a lagoon containing waste oil. Groundwater within 1,000 ft of the lagoon is contaminated. The second site is used to maintain, dispatch, and clean chemical-transportation tanks. Potentialmore » sources of groundwater contamination at the site include former wastewater lagoons, leaking storage drums, and leaking tank trucks. Groundwater at and immediately north of the property is contaminated. Organic compounds are manufactured at the third site. Potential sources of groundwater contamination at this site include landfilled industrial wastes. Groundwater underlying the property is contaminated, but there is no evidence of offsite groundwater contamination from this source. The fourth site is used to treat and dispose of hazardous wastes. The major source of groundwater contamination at this site is landfilled residue from waste-treatment processes. Groundwater underlying the property is contaminated, but there is no evidence of off-site groundwater contamination from this source.« less

First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Foreground Emission

NASA Technical Reports Server (NTRS)

Bennett, C. L.; Hill, R. S.; Hinshaw, G.; Nolta, M. R.; Odegard, N.; Page, L.; Spergel, D. N.; Weiland, J. L.; Wright, E. L.; Halpern, M.

2003-01-01

The WMAP mission has mapped the full sky to determine the geometry, content, and evolution of the universe. Full sky maps are made in five microwave frequency bands to separate the temperature anisotropy of the cosmic microwave background (CMB) from foreground emission, including diffuse Galactic emission and Galactic and extragalactic point sources. We define masks that excise regions of high foreground emission, so CMB analyses can became out with minimal foreground contamination. We also present maps and spectra of the individual emission components, leading to an improved understanding of Galactic astrophysical processes. The effectiveness of template fits to remove foreground emission from the WMAP data is also examined. These efforts result in a CMB map with minimal contamination and a demonstration that the WMAP CMB power spectrum is insensitive to residual foreground emission. We use a Maximum Entropy Method to construct a model of the Galactic emission components. The observed total Galactic emission matches the model to less than 1% and the individual model components are accurate to a few percent. We find that the Milky Way resembles other normal spiral galaxies between 408 MHz and 23 GHz, with a synchrotron spectral index that is flattest (beta(sub s) approx. -2.5) near star-forming regions, especially in the plane, and steepest (beta(sub s) approx. -3) in the halo. This is consistent with a picture of relativistic cosmic ray electron generation in star-forming regions and diffusion and convection within the plane. The significant synchrotron index steepening out of the plane suggests a diffusion process in which the halo electrons are trapped in the Galactic potential long enough to suffer synchrotron and inverse Compton energy losses and hence a spectral steepening. The synchrotron index is steeper in the WMAP bands than in lower frequency radio surveys, with a spectral break near 20 GHz to beta(sub s) less than -3. The modeled thermal dust spectral index is also steep in the WMAP bands, with beta(sub d) approx. = 2.2. Our model is driven to these conclusions by the low level of total foreground contamination at approx. 60 GHz. Microwave and Ha measurements of the ionized gas agree well with one another at about the expected levels. Spinning dust emission is limited to less than 5% of the Ka-band foreground emission. A catalog of 208 point sources is presented. The reliability of the catalog is 98%, i.e., we expect five of the 208 sources to be statistically spurious. The mean spectral index of the point sources is alpha approx. 0(beta approx. -2). Derived source counts suggest a contribution to the anisotropy power from unresolved sources of (15.0 +/- 1.4) x 10(exp -3)micro sq K sr at Q-band and negligible levels at V-band and W-band. The Sunyaev-Zeldovich effect is shown to be a negligible "contamination" to the maps.

Groundwater quality and hydrogeochemical properties of Torbali Region, Izmir, Turkey.

PubMed

Tayfur, Gokmen; Kirer, Tugba; Baba, Alper

2008-11-01

The large demand for drinking, irrigation and industrial water in the region of Torbali (Izmir, Turkey) is supplied from groundwater sources. Almost every factory and farm has private wells that are drilled without permission. These cause the depletion of groundwater and limiting the usage of groundwater. This study investigates spatial and temporal change in groundwater quality, relationships between quality parameters, and sources of contamination in Torbali region. For this purpose, samples were collected from 10 different sampling points chosen according to their geological and hydrogeological properties and location relative to factories, between October 2001 and July 2002. Various physical (pH, temperature, EC), chemical (calcium, magnesium, potassium, sodium, chloride, alkalinity, copper, chromium, cadmium, lead, zinc) and organic (nitrate, nitrite, ammonia, COD and cyanide) parameters were monitored. It was observed that the groundwater has bicarbonate alkalinity. Agricultural contamination was determined in the region, especially during the summer. Nitrite and ammonia concentrations were found to be above drinking water standard. Organic matter contamination was also investigated in the study area. COD concentrations were higher than the permissible limits during the summer months of the monitoring period.

Impact of wastewater-irrigation on in-household water contamination. A cohort study among urban farmers in Ahmedabad, India.

PubMed

Falkenberg, Timo; Saxena, Deepak; Kistemann, Thomas

2018-10-15

This cohort study explores the contribution of wastewater irrigation, in the context of WASH (Water, Sanitation, Hygiene), on in-household water contamination among urban farming households in Ahmedabad, India. Drinking water samples of 204 households in four peri-urban farming communities were collected from the point-of-source (PoS) and point-of-use (PoU) of each household four times over the 12-month follow-up period. Next to the quantification of E. coli, three household surveys (baseline, hygiene and farm) were conducted. Additionally, an observational spot-check was undertaken in bi-monthly intervals throughout the follow-up period. Significant positive differences in water quality between PoS and PoU samples were identified in 78% of households. During the monsoon, the peak of contamination, only 6% of households had access to safe drinking water at PoU. The Average Treatment Effect (ATE) of wastewater irrigation indicates an adverse effect on in-household water contamination, larger in effect size than the mitigation effect of access to sanitation or personal hygiene. To control transmission of fecal pathogens, effective barriers are required for wastewater irrigation similar to the necessity of ensuring access to sanitation and practicing adequate hygiene behavior. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Overview of environmental and hydrogeologic conditions at Barrow, Alaska

USGS Publications Warehouse

McCarthy, K.A.

1994-01-01

To assist the Federal Aviation Administration (FAA) in evaluating the potential effects of environmental contamination at their facility in Barrow, Alaska, a general assessment was made of the hydrologic system is the vicinity of the installation. The City of Barrow is located approximately 16 kilometers southwest of Point Barrow, the northernmost point in Alaska, and therefore lies within the region of continuous permafrost. Migration of surface or shallow- subsurface chemical releases in this environ- ment would be largely restricted by near-surface permafrost to surface water and the upper, suprapermafrost zone of the subsurface. In the arctic climate and tundra terrain of the Barrow area, this shallow environment has a limited capacity to attenuate the effects of either physical disturbances or chemical contamination and is therefore highly susceptible to degradation. Esatkuat Lagoon, the present drink- ing water supply for the City of Barrow, is located approximately 2 kilometers from the FAA facility. This lagoon is the only practical source of drinking water available to the City of Barrow because alternative sources of water in the area are (1) frozen throughout most of the year, (2) insufficient in volume, (3) of poor quality, or (4) too costly to develop and distribute.

Spatial and temporal variations of total and methylmercury concentrations in plankton from a mercury-contaminated and eutrophic reservoir in Guizhou Province, China.

PubMed

Wang, Qing; Feng, Xinbin; Yang, Yufeng; Yan, Haiyu

2011-12-01

Total mercury (THg) and methylmercury (MeHg) concentrations in four size fractions of plankton from three sampling stations in the Hg-contaminated and eutrophic Baihua Reservoir, Guizhou, China, were investigated for biomagnification and trophic transfer of Hg at different sites with various proximity to the major point sources of nutrients and metals. Total Hg concentrations in plankton of the various size fractions varied from 49 to 5,504 ng g(-1) and MeHg concentrations ranged from 3 to 101 ng g(-1). The percentage of Hg as MeHg varied from 0.16 to 70%. Total Hg and MeHg concentrations in plankton samples differed among the three sampling stations with different proximities from the major point sources. The plankton from the site closest to the dam contained the highest concentrations of MeHg. The successive increase of the ratios of MeHg to Hg from seston to macroplankton at all sites indicated that biomagnification is occurring along the plankton food web. However, biomagnification factors (BMF) for MeHg were low (1.5-2.0) between trophic levels. Concentrations of THg in seston decreased with an increase of chlorophyll concentrations, suggesting a significant dilution effect by the algae bloom for Hg. Eutrophication dilution may be a reason for lower MeHg accumulation by the four size classes of plankton in this Hg-contaminated reservoir. Copyright © 2011 SETAC.

Water contamination in urban south India: household storage practices and their implications for water safety and enteric infections.

PubMed

Brick, Thomas; Primrose, Beryl; Chandrasekhar, R; Roy, Sheela; Muliyil, Jayaprakash; Kang, Gagandeep

2004-10-01

Water contamination, at source and during household storage, is a major cause of enterically transmitted infections in developing countries. This study assessed contamination of the municipal water in a south Indian town, which obtains its water intermittently from a surface lake and by pumping subsurface water from a dry river bed, and monitored microbial contamination during household storage. All samples of the 'treated' municipal water were contaminated when freshly pumped, and on household storage, 25/37 (67%) showed increased contamination during storage periods from 1 to 9 days. Household storage in brass, but not in containers of other materials significantly decreased contamination of water (p = 0.04). This was confirmed in the laboratory by testing water seeded with 10(3) to 10(5) Escherichia coli per 100 ml stored in containers of different materials (p < 0.01). Despite the requirements for provision of safe drinking water in municipal areas, in practice the water supplied in Vellore is contaminated and current household storage practices increase the level of contamination in at least two-thirds of households. The implementation of locally appropriate point-of-use disinfection and safe household storage practices in developing countries is an urgent need to ensure a safe, reliable year-round supply in areas where clean water is not available.

Water quality risks of 'improved' water sources: evidence from Cambodia.

PubMed

Shaheed, A; Orgill, J; Ratana, C; Montgomery, M A; Jeuland, M A; Brown, J

2014-02-01

The objective of this study was to investigate the quality of on-plot piped water and rainwater at the point of consumption in an area with rapidly expanding coverage of 'improved' water sources. Cross-sectional study of 914 peri-urban households in Kandal Province, Cambodia, between July-August 2011. We collected data from all households on water management, drinking water quality and factors potentially related to post-collection water contamination. Drinking water samples were taken directly from a subsample of household taps (n = 143), stored tap water (n = 124), other stored water (n = 92) and treated stored water (n = 79) for basic water quality analysis for Escherichia coli and other parameters. Household drinking water management was complex, with different sources used at any given time and across seasons. Rainwater was the most commonly used drinking water source. Households mixed different water sources in storage containers, including 'improved' with 'unimproved' sources. Piped water from taps deteriorated during storage (P < 0.0005), from 520 cfu/100 ml (coefficient of variation, CV: 5.7) E. coli to 1100 cfu/100 ml (CV: 3.4). Stored non-piped water (primarily rainwater) had a mean E. coli count of 1500 cfu/100 ml (CV: 4.1), not significantly different from stored piped water (P = 0.20). Microbial contamination of stored water was significantly associated with observed storage and handling practices, including dipping hands or receptacles in water (P < 0.005), and having an uncovered storage container (P = 0.052). The microbial quality of 'improved' water sources in our study area was not maintained at the point of consumption, possibly due to a combination of mixing water sources at the household level, unsafe storage and handling practices, and inadequately treated piped-to-plot water. These results have implications for refining international targets for safe drinking water access as well as the assumptions underlying global burden of disease estimates, which posit that 'improved' sources pose minimal risks of diarrhoeal diseases. © 2013 John Wiley & Sons Ltd.

Inputs, source apportionment, and transboundary transport of pesticides and other polar organic contaminants along the lower Red River, Manitoba, Canada.

PubMed

Challis, Jonathan K; Cuscito, Leah D; Joudan, Shira; Luong, Kim H; Knapp, Charles W; Hanson, Mark L; Wong, Charles S

2018-04-20

The Red River originates in the U.S., drains into Lake Winnipeg, and is a significant pathway for nutrients. We investigate its role as a source for pesticides, pharmaceuticals, per- and polyfluoroalkyl substances (PFASs), and microbes bearing antibiotic resistance genes (ARGs). We delineate agricultural, urban, and rural land-use for organic contaminants to determine the extent of chemical transboundary riverine fluxes, and characterize levels and trends of organic contaminants and ARGs between spring and fall 2014 and 2015. The herbicide atrazine peaked at over 500 ng/L (14-day time-weighted average) near the border, indicating that the U.S. represents the major source into Canada from the Red River. Neonicotinoid insecticides had relatively constant concentrations, suggesting more widespread agricultural use in both countries. Pesticide concentrations were greatest post-application in June and July. Mass loadings of pesticides over the sampling periods, from the river to Lake Winnipeg, ranged from approximately 800 kg of atrazine, to 120 kg of thiamethoxam and clothianidin, to 40 kg of imidacloprid. Exposure distributions for atrazine exceeded benchmark water quality guidelines for protection of aquatic life (0.2% probability of exceeding chronic benchmark) with no exceedances for neonicotinoids. Seven pharmaceuticals were detected, mostly at low ng/L levels downstream of the City of Winnipeg wastewater treatment plant. Carbamazepine, the only pharmaceutical detected consistently at all sites, contributed on average 20 kg each year into Lake Winnipeg. While minor inputs were observed all along the river, city inputs represented the greatest source of pharmaceuticals to the river. Both PFASs and ARGs were observed consistently and ubiquitously, indicative of an anthropogenically-influenced system with no indications of any single point-source signature. While transboundary flux from the U.S. was an important source of pesticides to the Red River, especially for atrazine, observed concentrations of all measured contaminants suggest that known aquatic toxicological risk is minimal. Copyright © 2018 Elsevier B.V. All rights reserved.

Identifying and characterizing major emission point sources as a basis for geospatial distribution of mercury emissions inventories

NASA Astrophysics Data System (ADS)

Steenhuisen, Frits; Wilson, Simon J.

2015-07-01

Mercury is a global pollutant that poses threats to ecosystem and human health. Due to its global transport, mercury contamination is found in regions of the Earth that are remote from major emissions areas, including the Polar regions. Global anthropogenic emission inventories identify important sectors and industries responsible for emissions at a national level; however, to be useful for air transport modelling, more precise information on the locations of emission is required. This paper describes the methodology applied, and the results of work that was conducted to assign anthropogenic mercury emissions to point sources as part of geospatial mapping of the 2010 global anthropogenic mercury emissions inventory prepared by AMAP/UNEP. Major point-source emission sectors addressed in this work account for about 850 tonnes of the emissions included in the 2010 inventory. This work allocated more than 90% of these emissions to some 4600 identified point source locations, including significantly more point source locations in Africa, Asia, Australia and South America than had been identified during previous work to geospatially-distribute the 2005 global inventory. The results demonstrate the utility and the limitations of using existing, mainly public domain resources to accomplish this work. Assumptions necessary to make use of selected online resources are discussed, as are artefacts that can arise when these assumptions are applied to assign (national-sector) emissions estimates to point sources in various countries and regions. Notwithstanding the limitations of the available information, the value of this procedure over alternative methods commonly used to geo-spatially distribute emissions, such as use of 'proxy' datasets to represent emissions patterns, is illustrated. Improvements in information that would facilitate greater use of these methods in future work to assign emissions to point-sources are discussed. These include improvements to both national (geo-referenced) emission inventories and also to other resources that can be employed when such national inventories are lacking.

Assessment of trace metals contamination level, bioavailability and toxicity in sediments from Dakar coast and Saint Louis estuary in Senegal, West Africa.

PubMed

Diop, Cheikh; Dewaelé, Dorothée; Cazier, Fabrice; Diouf, Amadou; Ouddane, Baghdad

2015-11-01

Trace metals have the potential to associate with sediments that have been recognised as significant source of contamination for the benthic environment. The current study aims assessing the trace metals contamination level in sediments from Dakar coast and Saint Louis estuary, and to examine their bioavailability to predict potential toxicity of sediments. Surface sediment samples were collected between June 2012 and January 2013 in three sampling periods from eight stations. Trace metals were analysed using inductively coupled plasma-optical emission spectrometer. Geoaccumulation indexes (Igeo) showed strong pollution by Cd, Cr, Cu and Pb confirmed by enrichment factor (EF) suggesting that these metals derived from anthropogenic sources. Toxicity indexes exceeded one in several sites suggesting the potential effects on sediment-dwelling organisms, which may constitute a risk to populations' health. However, seasonal variability of metal bioavailability was noted, revealing the best period to monitor metal contamination. From an ecotoxicological point of view, concentrations of Cd, Cr, Cu and Pb were above the effects range low threshold limit of the sediment quality guidelines for adverse biological effects. In addition, with Pb concentrations above the effect range medium values in some sites, biological effects may occur. Copyright © 2014 Elsevier Ltd. All rights reserved.

p,p'-DDE bioaccumulation in female sea lions of the California Channel Islands

NASA Astrophysics Data System (ADS)

Connolly, John P.; Glaser, David

2002-05-01

An area of sediment on the Palos Verdes shelf and in Santa Monica Bay off Los Angeles, CA is contaminated with DDE and other breakdown products of DDT as a result of discharges of DDT through the Whites Point outfall. Elevated concentrations of DDE have been found in the water column of the Palos Verdes Shelf and in various fish species inhabiting the shelf and Santa Monica Bay. High concentrations have also been found in California sea lions from San Miguel Island and sea lion carcasses on Santa Catalina Island. These islands are located some distance from the Palos Verdes shelf and Santa Monica Bay. It was the purpose of this study to determine if it is likely that the Palos Verdes Shelf/Santa Monica Bay sediments were the principal source of the DDE in the Channel Island sea lions via a pathway from sediments to water and fish preyed on by sea lions. A time variable, age dependent, physiologically based toxicokinetic model of female California sea lions was developed. Mass and energy balance equations describe the uptake and loss of contaminants. The contaminants are partitioned among multiple body compartments, including lipid and non-lipid body tissue and milk. Contaminants are distributed into a fetus of females. Physiological and toxicokinetic data were used to establish rates of growth, respiration, reproduction and lactation, internal partitioning of DDE, efficiency of DDE uptake and rates of DDE excretion. The model was used to estimate the likely DDE exposure history of the sea lions in view of their DDE body burdens. Field-measured dietary composition and prey contaminant levels were then used to establish potential exposure to DDE from various regions within the Southern California Bight. Comparison of the estimated exposure history with that attainable from the various regions indicated that the more highly contaminated lactating females were exposed to prey at levels found only on the Palos Verdes Shelf and in Santa Monica Bay. Thus, it is likely that the sediments impacted by the Whites Point outfall were the source of much of the DDE and PCBs in these animals.

Assessment of heavy metal and bacterial pollution in coastal aquifers from SIPCOT industrial zones, Gulf of Mannar, South Coast of Tamil Nadu, India

NASA Astrophysics Data System (ADS)

Selvam, S.; Antony Ravindran, A.; Venkatramanan, S.; Singaraja, C.

2017-05-01

Heavy metals and microbiological contamination were investigated in groundwater in the industrial and coastal city of Thoothukudi. The main sources of drinking water in this area are water bores which are dug up to the depth of 10-50 m in almost every house. A number of chemical and pharmaceutical industries have been established since past three decades. Effluents from these industries are reportedly being directly discharged onto surrounding land, irrigation fields and surface water bodies forming point and non-point sources of contamination for groundwater in the study area. The study consists of the determination of physico-chemical properties, trace metals, heavy metals and microbiological quality of drinking water. Heavy metals were analysed using Inductively Coupled Plasma Mass Spectrometry and compared with the (WHO in Guidelines for drinking water quality, 2004) standards. The organic contamination was detected in terms of most probable number (MPN) test in order to find out faecal coliforms that were identified through biochemical tests. A comparison of the results of groundwater samples with WHO guidelines reveals that most of the groundwater samples are heavily contaminated with heavy metals like arsenic, selenium, lead, boron, aluminium, iron and vanadium. The selenium level was higher than 0.01 mg/l in 82 % of the study area and the arsenic concentration exceeded 0.01 mg/l in 42 % of the area. The results reveal that heavy metal contamination in the area is mainly due to the discharge of effluents from copper industries, alkali chemical industry, fertiliser industry, thermal power plant and sea food industries. The results showed that there are pollutions for the groundwater, and the total Coliform means values ranged from 0.6-145 MPN ml-1, faecal Coliform ranged from 2.2-143 MPN ml-1, Escherichia coli ranged from 0.9 to 40 MPN ml-1 and faecal streptococci ranged from 10-9.20 × 102 CFU ml-1. The coastal regions are highly contaminated with total coliform bacteria, faecal coliform bacteria and E. coli. This might be due to the mixing of sewage from Thoothukudi town through the Buckle channel and fishing activity.

Harmonised investigation of the occurrence of human enteric viruses in the leafy green vegetable supply chain in three European countries.

PubMed

Kokkinos, P; Kozyra, I; Lazic, S; Bouwknegt, M; Rutjes, S; Willems, K; Moloney, R; de Roda Husman, A M; Kaupke, A; Legaki, E; D'Agostino, M; Cook, N; Rzeżutka, A; Petrovic, T; Vantarakis, A

2012-12-01

Numerous outbreaks have been attributed to the consumption of raw or minimally processed leafy green vegetables contaminated with enteric viral pathogens. The aim of the present study was an integrated virological monitoring of the salad vegetables supply chain in Europe, from production, processing and point-of-sale. Samples were collected and analysed in Greece, Serbia and Poland, from 'general' and 'ad hoc' sampling points, which were perceived as critical points for virus contamination. General sampling points were identified through the analysis of background information questionnaires based on HACCP audit principles, and they were sampled during each sampling occasion where as-ad hoc sampling points were identified during food safety fact-finding visits and samples were only collected during the fact-finding visits. Human (hAdV) and porcine (pAdV) adenovirus, hepatitis A (HAV) and E (HEV) virus, norovirus GI and GII (NoV) and bovine polyomavirus (bPyV) were detected by means of real-time (RT-) PCR-based protocols. General samples were positive for hAdV, pAdV, HAV, HEV, NoV GI, NoV GII and bPyV at 20.09 % (134/667), 5.53 % (13/235), 1.32 % (4/304), 3.42 % (5/146), 2 % (6/299), 2.95 % (8/271) and 0.82 % (2/245), respectively. Ad hoc samples were positive for hAdV, pAdV, bPyV and NoV GI at 9 % (3/33), 9 % (2/22), 4.54 % (1/22) and 7.14 % (1/14), respectively. These results demonstrate the existence of viral contamination routes from human and animal sources to the salad vegetable supply chain and more specifically indicate the potential for public health risks due to the virus contamination of leafy green vegetables at primary production.

Spatial distribution and enteroparasite contamination in peridomiciliar soil and water in the Apucaraninha Indigenous Land, southern Brazil.

PubMed

da Silva, Joseane Balan; Piva, Camila; Falavigna-Guilherme, Ana Lúcia; Rossoni, Diogo Francisco; de Ornelas Toledo, Max Jean

2016-04-01

The prevalence and distribution of soil and water samples contaminated with enteroparasites of humans and animals with zoonotic potential (EHAZP) in Apucaraninha Indigenous Land (AIL), southern Brazil, was evaluated. An environmental survey was conducted to evaluate the presence of parasitic forms in peridomiciliary soil and associated variables. Soil samples were collected from 40/293 domiciles (10 domiciles per season), from November 2010 to June 2011, and evaluated by modified methods of Faust et al. and Lutz. Analyses of water from seven consumption sites were also performed. The overall prevalence of soil samples contaminated by EHAZP was 23.8 %. The most prevalent parasitic forms were cyst of Entamoeba spp. and eggs of Ascaris spp. The highest prevalence of contaminated soil samples was observed in winter (31 %). The probability map obtained with geostatistical analyses showed an average of 47 % soil contamination at a distance of approximately 140 m. The parasitological analysis of water did not detect Giardia spp. or Cryptosporidium spp. and showed that all collection points were within the standards of the Brazilian law. However, the microbiological analysis showed the presence of Escherichia coli in 6/7 sampled points. Despite the low level of contamination by EHAZP in peridomiciliar soil and the absence of pathogenic protozoa in water, the AIL soil and water (due to the presence of fecal coliforms) are potential sources of infection for the population, indicating the need for improvements in sanitation and water treatment, in addition periodic treatment of the population with antiparasitic.

A CMB foreground study in WMAP data: Extragalactic point sources and zodiacal light emission

NASA Astrophysics Data System (ADS)

Chen, Xi

The Cosmic Microwave Background (CMB) radiation is the remnant heat from the Big Bang. It serves as a primary tool to understand the global properties, content and evolution of the universe. Since 2001, NASA's Wilkinson Microwave Anisotropy Probe (WMAP) satellite has been napping the full sky anisotropy with unprecedented accuracy, precision and reliability. The CMB angular power spectrum calculated from the WMAP full sky maps not only enables accurate testing of cosmological models, but also places significant constraints on model parameters. The CMB signal in the WMAP sky maps is contaminated by microwave emission from the Milky Way and from extragalactic sources. Therefore, in order to use the maps reliably for cosmological studies, the foreground signals must be well understood and removed from the maps. This thesis focuses on the separation of two foreground contaminants from the WMAP maps: extragalactic point sources and zodiacal light emission. Extragalactic point sources constitute the most important foreground on small angular scales. Various methods have been applied to the WMAP single frequency maps to extract sources. However, due to the limited angular resolution of WMAP, it is possible to confuse positive CMB excursions with point sources or miss sources that are embedded in negative CMB fluctuations. We present a novel CMB-free source finding technique that utilizes the spectrum difference of point sources and CMB to form internal linear combinations of multifrequency maps to suppress the CMB and better reveal sources. When applied to the WMAP 41, 64 and 94 GHz maps, this technique has not only enabled detection of sources that are previously cataloged by independent methods, but also allowed disclosure of new sources. Without the noise contribution from the CMB, this method responds rapidly with the integration time. The number of detections varies as 0( t 0.72 in the two-band search and 0( t 0.70 in the three-band search from one year to five years, separately, in comparison to t 0.40 from the WMAP catalogs. Our source catalogs are a good supplement to the existing WMAP source catalogs, and the method itself is proven to be both complementary to and competitive with all the current source finding techniques in WMAP maps. Scattered light and thermal emission from the interplanetary dust (IPD) within our Solar System are major contributors to the diffuse sky brightness at most infrared wavelengths. For wavelengths longer than 3.5 mm, the thermal emission of the IPD dominates over scattering, and the emission is often referred to as the Zodiacal Light Emission (ZLE). To set a limit of ZLE contribution to the WMAP data, we have performed a simultaneous fit of the yearly WMAP time-ordered data to the time variation of ZLE predicted by the DIRBE IPD model (Kelsallet al. 1998) evaluated at 240 mm, plus [cursive l] = 1 - 4 CMB components. It is found that although this fitting procedure can successfully recover the CMB dipole to a 0.5% accuracy, it is not sensitive enough to determine the ZLE signal nor the other multipole moments very accurately.

Microplastic analysis in the South Funen Archipelago, Baltic Sea, implementing manta trawling and bulk sampling.

PubMed

Tamminga, Matthias; Hengstmann, Elena; Fischer, Elke Kerstin

2018-03-01

Microplastic contamination in surface waters of the South Funen Archipelago in Denmark was assessed. Therefore, ten manta trawls were conducted in June 2015. Moreover, 31 low-volume bulk samples were taken to evaluate, whether consistent results in comparison to the net-based approach can be obtained. Microplastic contamination in the South Funen Archipelago (0.07 ± 0.02 particles/m3) is slightly below values reported before. The sheltered position of the study area, low population pressure on adjacent islands and the absence of any major potential point sources were identified as major factors explaining the low concentration of microplastics. Within the Archipelago, harbors or marinas and the associated vessel traffic are the most probable sources of microplastics. The concentration of microplastics in low-volume bulk samples is not comparable to manta trawl results. This is mainly due to insufficient representativeness of the bulk sample volumes.

Coastal aquifers: Scientific advances in the face of global environmental challenges

NASA Astrophysics Data System (ADS)

Post, Vincent E. A.; Werner, Adrian D.

2017-08-01

Coastal aquifers embody the subsurface transition between terrestrial and marine systems, and form the almost invisible pathway for tremendous volumes of freshwater that flow to the ocean. Changing conditions of the earth's landscapes and oceans can disrupt the fragile natural equilibrium between fresh and saltwater that exists in coastal zones. Among these, over-abstraction of groundwater is considered the leading man-made cause of seawater intrusion. Moreover, many of the world's largest urban settings, where sources of contamination are profuse, have been built over the freshwater in coastal aquifers. Thus, coastal aquifers are important receptors of human impacts to water on Earth (Michael et al., 2017). This Special Issue on 'Investigation and Management of Coastal Aquifers' contains current scientific advances on the topic, dealing with the storage and quality of water, affected by stressors ranging in scale from point source contamination to global climate change.

Measurement of helium isotopes in soil gas as an indicator of tritium groundwater contamination.

PubMed

Olsen, Khris B; Dresel, P Evan; Evans, John C; McMahon, William J; Poreda, Robert

2006-05-01

The focus of this study was to define the shape and extent of tritium groundwater contamination emanating from a legacy burial ground and to identify vadose zone sources of tritium using helium isotopes (3He and 4He) in soil gas. Helium isotopes were measured in soil-gas samples collected from 70 sampling points around the perimeter and downgradient of a burial ground that contains buried radioactive solid waste. The soil-gas samples were analyzed for helium isotopes using rare gas mass spectrometry. 3He/4He ratios, reported as normalized to the air ratio (RA), were used to locate the tritium groundwater plume emanating from the burial ground. The 3He (excess) suggested that the general location of the tritium source is within the burial ground. This study clearly demonstrated the efficacy of the 3He method for application to similar sites elsewhere within the DOE weapons complex.

Real-time identification of indoor pollutant source positions based on neural network locator of contaminant sources and optimized sensor networks.

PubMed

Vukovic, Vladimir; Tabares-Velasco, Paulo Cesar; Srebric, Jelena

2010-09-01

A growing interest in security and occupant exposure to contaminants revealed a need for fast and reliable identification of contaminant sources during incidental situations. To determine potential contaminant source positions in outdoor environments, current state-of-the-art modeling methods use computational fluid dynamic simulations on parallel processors. In indoor environments, current tools match accidental contaminant distributions with cases from precomputed databases of possible concentration distributions. These methods require intensive computations in pre- and postprocessing. On the other hand, neural networks emerged as a tool for rapid concentration forecasting of outdoor environmental contaminants such as nitrogen oxides or sulfur dioxide. All of these modeling methods depend on the type of sensors used for real-time measurements of contaminant concentrations. A review of the existing sensor technologies revealed that no perfect sensor exists, but intensity of work in this area provides promising results in the near future. The main goal of the presented research study was to extend neural network modeling from the outdoor to the indoor identification of source positions, making this technology applicable to building indoor environments. The developed neural network Locator of Contaminant Sources was also used to optimize number and allocation of contaminant concentration sensors for real-time prediction of indoor contaminant source positions. Such prediction should take place within seconds after receiving real-time contaminant concentration sensor data. For the purpose of neural network training, a multizone program provided distributions of contaminant concentrations for known source positions throughout a test building. Trained networks had an output indicating contaminant source positions based on measured concentrations in different building zones. A validation case based on a real building layout and experimental data demonstrated the ability of this method to identify contaminant source positions. Future research intentions are focused on integration with real sensor networks and model improvements for much more complicated contamination scenarios.

Deep challenges for China's war on water pollution.

PubMed

Han, Dongmei; Currell, Matthew J; Cao, Guoliang

2016-11-01

China's Central government has released an ambitious plan to tackle the nation's water pollution crisis. However, this is inhibited by a lack of data, particularly for groundwater. We compiled and analyzed water quality classification data from publicly available government sources, further revealing the scale and extent of the crisis. We also compiled nitrate data in shallow and deep groundwater from a range of literature sources, covering 52 of China's groundwater systems; the most comprehensive national-scale assessment yet. Nitrate pollution at levels exceeding the US EPA's maximum contaminant level (10 mg/L NO 3 N) occurs at the 90th percentile in 25 of 36 shallow aquifers and 10 out of 37 deep or karst aquifers. Isotopic compositions of groundwater nitrate (δ 15 N and δ 18 O NO3 values ranging from -14.9‰ to 35.5‰ and -8.1‰ to 51.0‰, respectively) indicate many nitrate sources including soil nitrogen, agricultural fertilizers, untreated wastewater and/or manure, and locally show evidence of de-nitrification. From these data, it is clear that contaminated groundwater is ubiquitous in deep aquifers as well as shallow groundwater (and surface water). Deep aquifers contain water recharged tens of thousands of years before present, long before widespread anthropogenic nitrate contamination. This groundwater has therefore likely been contaminated due to rapid bypass flow along wells or other conduits. Addressing the issue of well condition is urgently needed to stop further pollution of China's deep aquifers, which are some of China's most important drinking water sources. China's new 10-point Water Pollution Plan addresses previous shortcomings, however, control and remediation of deep groundwater pollution will take decades of sustained effort. Copyright © 2016. Published by Elsevier Ltd.

Ground-water protection, low-level waste, and below regulatory concern: What`s the connection?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gruhlke, J.M.; Galpin, F.L.

1991-12-31

The Environmental Protection Agency (EPA) has a responsibility to protect ground water and drinking water under a wide variety of statutes. Each statute establishes different but specific requirements for EPA and applies to diverse environmental contaminants. Radionuclides are but one of the many contaminants subject to this regulatory matrix. Low-level radioactive waste (LLW) and below regulatory concern (BRC) are but two of many activities falling into this regulatory structure. The nation`s ground water serves as a major source of drinking water, supports sensitive ecosystems, and supplies the needs of agriculture and industry. Ground water can prove enormously expensive to cleanmore » up. EPA policy for protecting ground water has evolved considerably over the last ten years. The overall goal is to prevent adverse effects to human health, both now and in the future, and to protect the integrity of the nation`s ground-water resources. The Agency uses the Maximum Contaminant Levels (MCLs) under the Safe Drinking Water Act as reference points for protection in both prevention and remediation activities. What`s the connection? Both low-level waste management and disposal activities and the implementation of below regulatory concern related to low-level waste disposal have the potential for contaminating ground water. EPA is proposing to use the MCLs as reference points for low-level waste disposal and BRC disposal in order to define limits to the environmental contamination of ground water that is, or may be, used for drinking water.« less

Nitrate, volatile organic compounds, and pesticides in ground water--a summary of selected studies from New Jersey and Long Island, New York

USGS Publications Warehouse

Clawges, Rick M.; Stackelberg, Paul E.; Ayers, Mark A.; Vowinkel, Eric F.

1999-01-01

This report describes the ground-water systems in the unconsolidated sand and gravel aquifers of the Coastal Plain of New Jersey and Long Island and in the fractured bedrock and valley-fill aquifers of northern New Jersey; summarizes current knowledge about the occurrence and distribution of nitrate, volatile organic compounds (VOCs), and pesticides in these systems; and explains why some ground-water systems are more vulnerable to comtamination than others. Although the vulnerability of ground water to contamination from the land surface is influenced by many factors, the degree of aquifer confinement, the depth of the well, and the surrounding land use are key factors. Unconfined aquifers generally are much more vulnerable to contamination than confined aquifers. For a well in a confined aquifer, the farther the well is from the unconfined area, the less vulnerable it is to contamination. Generally, the deeper the well, the less vulnerable it is to contamination. Finally, because human activities greatly affect the quality of water that recharges an aquifer, the amount and type of land use in the area that contributes water to the well is a key factor in determining vulnerability. Nitrate contamination of ground water typically occurs in agricultural and residential areas, especially where the aquifer is very permeable and unconfined and nitrogen-fertilizer use is high. In New Jersey and on Long Island, concentrations of nitrate exceed the U.S. Environmental Protection Agency Maximum Contaminant Level (MCL) more often than those of VOCs or pesticides. Nitrate contamination generally is associated with nonpoint sources. VOC contamination of ground water occurs primarily in urban areas, especially in mixed urban and industrial areas where chemicals are used. In general, VOC concentrations are low and do not exceed MCLs. High concentrations of VOCs generally are associated with point sources. Pesticide contamination of ground water occurs in some agricultural and residential areas, where the aquifer is very permeable and unconfined, and where the chemicals are used. Concentrations of pesticides in New Jersey and on Long Island generally are low; in agricultural areas of Long Island, however, some have been found to exceed MCLs. Pesticide contamination generally is associated with nonpoint sources.

International Space Station External Contamination Status

NASA Technical Reports Server (NTRS)

Mikatarian, Ron; Soares, Carlos

2000-01-01

PResentation slides examine external contamination requirements; International Space Station (ISS) external contamination sources; ISS external contamination sensitive surfaces; external contamination control; external contamination control for pre-launch verification; flight experiments and observations; the Space Shuttle Orbiter waste water dump, materials outgassing, active vacuum vents; example of molecular column density profile, modeling and analysis tools; sources of outgassing induced contamination analyzed to date, quiescent sources, observations on optical degradation due to induced external contamination in LEO; examples of typical contaminant and depth profiles; and status of the ISS system, material outgassing, thruster plumes, and optical degradation.

Point Spread Function of ASTRO-H Soft X-Ray Telescope (SXT)

NASA Technical Reports Server (NTRS)

Hayashi, Takayuki; Sato, Toshiki; Kikuchi, Naomichi; Iizuka, Ryo; Maeda, Yoshitomo; Ishida, Manabu; Kurashima, Sho; Nakaniwa, Nozomi; Okajima, Takashi; Mori, Hideyuki;

Risk Assessment and Source Identification of 17 Metals and Metalloids on Soils from the Half-Century Old Tungsten Mining Areas in Lianhuashan, Southern China.

PubMed

Guo, Li; Zhao, Weituo; Gu, Xiaowen; Zhao, Xinyun; Chen, Juan; Cheng, Shenggao

2017-11-29

Background: Mining activities always emit metal(loid)s into the surrounding environment, where their accumulation in the soil may pose risks and hazards to humans and ecosystems. Objective : This paper aims to determine of the type, source, chemical form, fate and transport, and accurate risk assessment of 17 metal(loid) contaminants including As, Cd, Cu, Ni, Pb, Zn, Cr, Ag, B, Bi, Co, Mo, Sb, Ti, V, W and Sn in the soils collected from an abandoned tungsten mining area, and to guide the implementing of appropriate remediation strategies. Methods : Contamination factors ( CFs ) and integrated pollution indexes ( IPIs ) and enrichment factors ( EFs ) were used to assess their ecological risk and the sources were identified by using multivariate statistics analysis, spatial distribution investigation and correlation matrix. Results : The IPI and EF values indicated the soils in the mine site and the closest downstream one were extremely disturbed by metal(loid)s such as As, Bi, W, B, Cu, Pb and Sn, which were emitted from the mining wastes and acid drainages and delivered by the runoff and human activities. Arsenic contamination was detected in nine sites with the highest CF values at 24.70 next to the mining site. The Cd contamination scattered in the paddy soils around the resident areas with higher fraction of bioavailable forms, primarily associated with intense application of phosphorus fertilizer. The lithogenic elements V, Ti, Ag, Ni, Sb, Mo exhibit low contamination in all sampling points and their distribution were depended on the soil texture and pedogenesis process. Conclusions : The long term historical mining activities have caused severe As contamination and higher enrichment of the other elements of orebody in the local soils. The appropriate remediation treatment approach should be proposed to reduce the bioavailability of Cd in the paddy soils and to immobilize As to reclaim the soils around the mining site. Furthermore, alternative fertilizing way and irrigating water sources are urgencies to reduce the input of Cd and As into the local soils effectively.

Risk Assessment and Source Identification of 17 Metals and Metalloids on Soils from the Half-Century Old Tungsten Mining Areas in Lianhuashan, Southern China

PubMed Central

Guo, Li; Zhao, Weituo; Gu, Xiaowen; Zhao, Xinyun; Chen, Juan; Cheng, Shenggao

2017-01-01

Background: Mining activities always emit metal(loid)s into the surrounding environment, where their accumulation in the soil may pose risks and hazards to humans and ecosystems. Objective: This paper aims to determine of the type, source, chemical form, fate and transport, and accurate risk assessment of 17 metal(loid) contaminants including As, Cd, Cu, Ni, Pb, Zn, Cr, Ag, B, Bi, Co, Mo, Sb, Ti, V, W and Sn in the soils collected from an abandoned tungsten mining area, and to guide the implementing of appropriate remediation strategies. Methods: Contamination factors (CFs) and integrated pollution indexes (IPIs) and enrichment factors (EFs) were used to assess their ecological risk and the sources were identified by using multivariate statistics analysis, spatial distribution investigation and correlation matrix. Results: The IPI and EF values indicated the soils in the mine site and the closest downstream one were extremely disturbed by metal(loid)s such as As, Bi, W, B, Cu, Pb and Sn, which were emitted from the mining wastes and acid drainages and delivered by the runoff and human activities. Arsenic contamination was detected in nine sites with the highest CF values at 24.70 next to the mining site. The Cd contamination scattered in the paddy soils around the resident areas with higher fraction of bioavailable forms, primarily associated with intense application of phosphorus fertilizer. The lithogenic elements V, Ti, Ag, Ni, Sb, Mo exhibit low contamination in all sampling points and their distribution were depended on the soil texture and pedogenesis process. Conclusions: The long term historical mining activities have caused severe As contamination and higher enrichment of the other elements of orebody in the local soils. The appropriate remediation treatment approach should be proposed to reduce the bioavailability of Cd in the paddy soils and to immobilize As to reclaim the soils around the mining site. Furthermore, alternative fertilizing way and irrigating water sources are urgencies to reduce the input of Cd and As into the local soils effectively. PMID:29186069

Evaluating Crustal Contamination Effects on the Lithophile Trace Element Budget of Shergottites

NASA Technical Reports Server (NTRS)

Brandon, A. D.; Ferdous, J.; Peslier, A. H.

2017-01-01

The origin of the incompatible trace element (ITE) enriched compositions of shergottites has been a point of contention for decades [1-2]. Two scenarios have been proposed, the first is that enriched shergottite compositions reflect an ITE-enriched mantle source, whereas in the second, the ITE enrichment reflects crustal contamination of mantle-derived parent magmas. Evidence supporting the first scenario is that the ITE-enriched shergottite compositions are consistent with the outcomes of magma ocean crystallization [3], and that Os-Nd isotope relationships for shergottites cannot be explained by realistic crustal contamination models [4]. In contrast, Cl and S isotopes are consistent with shergottite magmas interacting with Mars crust [5,6], and ITE-enriched olivine-hosted melt inclusions and interstitial glass are found in depleted shergottite Yamato 980459 [7]. These findings indicate that some level of crustal interaction occurred but the question of whether ITE-enrichments in some bulk shergottites reflect crustal contamination remains open. Recently, a Mars crustal breccia meteorite has been found, NWA 7034 and its paired stones, that is our best analogue to an average of Mars ancient crust [8-10]. This allows for better constraints on crustal contamination of shergottite magmas. We modeled magma-crust mixing and assimilation-fractional crystallization (AFC) using ITE-depleted shergottite compositions and bulk NWA 7034 and its clasts as end-members. The results of these models indicate that crustal contamination can only explain the ITE-enriched compositions of some bulk shergottites under unusual circumstances. It is thus likely that the shergottite range of compositions reflects primarily mantle sources.

Coliform Sources and Mechanisms for Regrowth in Household Drinking Water in Limpopo, South Africa.

PubMed

Mellor, Jonathan E; Smith, James A; Samie, Amidou; Dillingham, Rebecca A

2013-09-01

Resource-limited communities throughout the developing world face significant environmental health problems related to the myriad of coliform sources within those communities. This study comprehensively investigated contamination sources and the biological and chemical mechanisms sustaining them in two adjacent communities in rural Limpopo, South Africa. An 8-month study was conducted of household ( n = 14) and source water quality, measurements of biofilm layers on the inside of household water storage containers and water transfer devices, and also hand-based coliforms and hand-washing effectiveness. A 7-day water container incubation experiment was also performed to determine the biological and chemical changes that occur in a household water storage container independent of human interference. Results indicate that household drinking water frequently becomes contaminated after collection but before consumption (197 versus 1,046 colony-forming units/100 mL; n = 266; p < 0.001). The most important contamination sources include biofilm layers on the inside of storage containers (1.85 ± 1.59 colony-forming units/cm 2 ; n = 44), hands (5,097 ± 2,125 colony-forming units/hand; n = 48), and coliform regrowth resulting from high assimilable organic carbon (AOC) levels during storage. A maximum specific growth rate, μ max , of 0.072 ± 0.003 h -1 was determined for total coliform bacteria on AOC, and a high correlation between AOC concentrations and the growth potential of total coliform bacteria was observed. These results support the implementation of point-of-use water treatment and other interventions aimed at maintaining the safe water chain and preventing biological regrowth.

Coliform Sources and Mechanisms for Regrowth in Household Drinking Water in Limpopo, South Africa

PubMed Central

Mellor, Jonathan E.; Samie, Amidou; Dillingham, Rebecca A.

2014-01-01

Resource-limited communities throughout the developing world face significant environmental health problems related to the myriad of coliform sources within those communities. This study comprehensively investigated contamination sources and the biological and chemical mechanisms sustaining them in two adjacent communities in rural Limpopo, South Africa. An 8-month study was conducted of household (n = 14) and source water quality, measurements of biofilm layers on the inside of household water storage containers and water transfer devices, and also hand-based coliforms and hand-washing effectiveness. A 7-day water container incubation experiment was also performed to determine the biological and chemical changes that occur in a household water storage container independent of human interference. Results indicate that household drinking water frequently becomes contaminated after collection but before consumption (197 versus 1,046 colony-forming units/100 mL; n = 266; p < 0.001). The most important contamination sources include biofilm layers on the inside of storage containers (1.85 ± 1.59 colony-forming units/cm2; n = 44), hands (5,097 ± 2,125 colony-forming units/hand; n = 48), and coliform regrowth resulting from high assimilable organic carbon (AOC) levels during storage. A maximum specific growth rate, μmax, of 0.072 ± 0.003 h−1 was determined for total coliform bacteria on AOC, and a high correlation between AOC concentrations and the growth potential of total coliform bacteria was observed. These results support the implementation of point-of-use water treatment and other interventions aimed at maintaining the safe water chain and preventing biological regrowth. PMID:25190902

Point-of-use Unit Based on Gravity Ultrafiltration Removes Waterborne Gastrointestinal Pathogens from Untreated Water Sources in Rural Communities.

PubMed

Chaidez, Cristóbal; Ibarra-Rodríguez, Juan R; Valdez-Torres, José Benigno; Soto, Marcela; Gerba, Charles P; Castro-Del Campo, Nohelia

2016-09-01

In developing countries, rural communities often face the lack of potable water infrastructure and must rely on untreated sources for drinking, which are often contaminated with waterborne pathogens. The use of home water treatment devices is seen as one means of reducing the risk of exposure to waterborne pathogens. The aim of this study was to evaluate the microbiological and physicochemical performance of a simple in-home point-of-use device based on gravity ultrafiltration through an ultrafilter membrane. Twenty-five randomly selected households from 2 rural communities in Culiacán, Mexico, were enrolled. Water samples were collected before and after treatment and during storage for a period of 8 weeks. Heterotrophic bacteria, total coliforms, fecal coliforms, Escherichia coli, and Giardia spp were quantified, as well as various physicochemical parameters. All of the untreated water samples contained high levels of indicator bacteria, but none were detected in the treated water fulfilling the requirements set by the Mexican Norm (NOM-127-SSA1-1994) and the World Health Organization guidelines for drinking water. However, indicator bacteria (fecal coliforms and E coli) were detected in every sample from water stored 24 hours after treatment. This study demonstrated that point-of-use filters using gravity-fed ultrafilters are a low-cost, effective water treatment technology for water of poor microbial quality. However, further identification of the sources and mechanisms by which water is contaminated when stored after treatment will help with designing and implementing better strategies for keeping water safe for domestic use. Copyright © 2016 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

Root cause investigation of a viral contamination incident occurred during master cell bank (MCB) testing and characterization--a case study.

PubMed

Chen, Dayue; Nims, Raymond; Dusing, Sandra; Miller, Pamela; Luo, Wen; Quertinmont, Michelle; Parekh, Bhavin; Poorbaugh, Josh; Boose, Jeri Ann; Atkinson, E Morrey

2008-11-01

An adventitious agent contamination occurred during a routine 9 CFR bovine viral screening test at BioReliance for an Eli Lilly Chinese Hamster Ovary (CHO) cell-derived Master Cell Bank (MCB) intended for biological production. Scientists from the sponsor (Eli Lilly and Company) and the testing service company (BioReliance) jointly conducted a systematic investigation in an attempt to determine the root cause of the contamination. Our investigation resulted in the identification of the viral nature of the contaminant. Subsequent experiments indicated that the viral contaminant was a non-enveloped and non-hemadsorbing virus. Transmission electron microscopy (TEM) revealed that the viral contaminant was 25-30 nm in size and morphologically resembled viruses of the family Picornaviridae. The contaminant virus was readily inactivated when exposed to acidic pH, suggesting that the viral contaminant was a member of rhinoviruses. Although incapable of infecting CHO cells, the viral contaminant replicated efficiently in Vero cell with a life cycle of approximately 16 h. Our investigation provided compelling data demonstrating that the viral contaminant did not originate from the MCB. Instead, it was introduced into the process during cell passaging and a possible entry point was proposed. We identified the viral contaminant as an equine rhinitis A virus using molecular cloning and DNA sequencing. Finally, our investigation led us to conclude that the source of the viral contaminant was the equine serum added to the cell growth medium in the 9 CFR bovine virus test.

Site-specific variability in BTEX biodegradation under denitrifying conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kao, C.M.; Borden, R.C.

1997-03-01

Laboratory microcosm experiments were conducted to evaluate the feasibility of benzene, toluene, ethylbenzene, m-xylene, and o-xylene (BTEX) biodegradation under denitrifying conditions. Nine different sources of inocula, including contaminated and uncontaminated soil cores from four different sites and activated sludge, were used to establish microcosms. BTEX was not degraded under denitrifying conditions in microcosms inoculated with aquifer material from Rocky Point and Traverse City. However, rapid depletion of glucose under denitrifying conditions was observed in microcosms containing Rocky Point aquifer material. TEX degradation was observed in microcosms containing Rocky Point aquifer material. TEX degradation was observed in microcosms containing aquifer materialmore » from Fort Bragg and Sleeping Bear Dunes and sewage sludge. Benzene was recalcitrant in all microcosms tested. The degradation of o-xylene ceased after toluene, ethylbenzene, and m-xylene were depleted in the Fort Bragg and sludge microcosms, but o-xylene continued to degrade in microcosms with contaminated Sleeping Bear Dunes soil. The most probable number (MPN) of denitrifiers in these nine different inocula were measured using a microtiter technique. There was no correlation between the MPN of denitrifiers and the TEX degradation rate under denitrifying conditions. Experimental results indicate that the degradation sequence and TEX degradation rate under denitrifying conditions may differ among sites. Results also indicate that denitrification alone may not be a suitable bioremediation technology for gasoline-contaminated aquifers because of the inability of denitrifiers to degrade benzene.« less

Assessing the impact of dairy waste lagoons on groundwater quality using a spatial analysis of vadose zone and groundwater information in a coastal phreatic aquifer.

PubMed

Baram, S; Kurtzman, D; Ronen, Z; Peeters, A; Dahan, O

2014-01-01

Dairy waste lagoons are considered to be point sources of groundwater contamination by chloride (Cl(-)), different nitrogen-species and pathogens/microorganisms. The objective of this work is to introduce a methodology to assess the past and future impacts of such lagoons on regional groundwater quality. The method is based on a spatial statistical analysis of Cl(-) and total nitrogen (TN) concentration distributions in the saturated and the vadose (unsaturated) zones. The method provides quantitative data on the relation between the locations of dairy lagoons and the spatial variability in Cl(-) and TN concentrations in groundwater. The method was applied to the Beer-Tuvia region, Israel, where intensive dairy farming has been practiced for over 50 years above the local phreatic aquifer. Mass balance calculations accounted for the various groundwater recharge and abstraction sources and sinks in the entire region. The mass balances showed that despite the small surface area covered by the dairy lagoons in this region (0.8%), leachates from lagoons have contributed 6.0% and 12.6% of the total mass of Cl(-) and TN (mainly as NO3(-)-N) added to the aquifer. The chemical composition of the aquifer and vadose zone water suggested that irrigated agricultural activity in the region is the main contributor of Cl(-) and TN to the groundwater. A low spatial correlation between the Cl(-) and NO3(-)-N concentrations in the groundwater and the on-land location of the dairy farms strengthened this assumption, despite the dairy waste lagoon being a point source for groundwater contamination by Cl(-) and NO3(-)-N. Mass balance calculations, for the vadose zone of the entire region, indicated that drying of the lagoons would decrease the regional groundwater salinization process (11% of the total Cl(-) load is stored under lagoons). A more considerable reduction in the groundwater contamination by NO3(-)-N is expected (25% of the NO3(-)-N load is stored under lagoons). Results demonstrate that analyzing vadose zone and groundwater data by spatial statistical analysis methods can significantly contribute to the understanding of the relations between groundwater contaminating sources, and to assessing appropriate remediation steps. Copyright © 2013 Elsevier Ltd. All rights reserved.

Sedimentary record and anthropogenic pollution of a complex, multiple source fed dam reservoirs: An example from the Nové Mlýny reservoir, Czech Republic.

PubMed

Sedláček, Jan; Bábek, Ondřej; Nováková, Tereza

2017-01-01

While numerous studies of dam reservoirs contamination are reported world-wide, we present a missing link in the study of reservoirs sourced from multiple river catchments. In such reservoirs, different point sources of contaminants and variable composition of their sedimentary matrices add to extremely complex geochemical patterns. We studied a unique, step-wise filled Nové Mlýny dam reservoir, Czech Republic, which consists of three interconnected sub-basins. Their source areas are located in units with contrasting geology and different levels and sources of contamination. The aim of this study is to provide an insight into the provenance of the sediment, including lithogenic elements and anthropogenic pollutants, to investigate the sediment dispersal across the reservoir, and to assess the heavy metal pollution in each basin. The study is based on multi-proxy stratigraphic analysis and geochemistry of sediment cores. There is a considerable gradient in the sediment grain size, brightness, MS and geochemistry, which reflects changing hydrodynamic energy conditions and primary pelagic production of CaCO 3 . The thickness of sediments generally decreases from proximal to distal parts, but underwater currents can accumulate higher amounts of sediments in distal parts near the thalweg line. Average sedimentation rates vary over a wide range from 0.58cm/yr to 2.33cm/yr. In addition, the petrophysical patterns, concentrations of lithogenic elements and their ratios made it possible to identify two main provenance areas, the Dyje River catchment (upper basin) and the Svratka and Jihlava River catchments (middle and lower basin). Enrichment factors (EF) were used for distinguishing the anthropogenic element contribution from the local background levels. We found moderate Zn and Cu pollution (EF ~2 to 5) in the upper basin and Zn, Cu and Pb (EF ~2 to 4.5) in the middle basin with the peak contamination in the late 1980s, indicating that the two basins have different contamination histories. Copyright © 2016 Elsevier B.V. All rights reserved.

Bacterial source tracking guides management of boat head waste in a coastal resort area.

PubMed

Mallin, Michael A; Haltom, Mary I; Song, Bongkeun; Tavares, Mary E; Dellies, Stephen P

2010-12-01

Fecal contamination of water bodies causes a public health problem and economic loss. To control such contamination management actions need to be guided by sound science. From 2007-2009 a study was undertaken to determine the sources of fecal bacteria contamination to the marine waters adjoining the Town of Wrightsville Beach, North Carolina, USA. The research effort included sampling for fecal coliform and Enterococcus bacteria, sampling for optical brighteners, dye studies, and use of molecular bacterial source tracking techniques including polymerase chain reaction (PCR) and terminal restriction fragment polymorphism (T-RFLP) fingerprinting of the Bacteroides-Prevotella group. Of the 96 samples collected from nine locations during the study, the water contact standard for Enterococcus was exceeded on 13 occasions. The T-RFLP fingerprint analyses demonstrated that the most widespread source of fecal contamination was human, occurring in 38% of the samples, with secondary ruminant and avian sources also detected. Optical brightener concentrations were low, reflecting a lack of sewage line leakage or spills. A lack of sewer leaks and lack of septic systems in the town pointed toward discharge from boat heads into the marine waters as the major cause of fecal contamination; this was supported by dye studies. Based on these data, the Town initiated action to have the U.S. Environmental Protection Agency declare the coastal waters (out to 3 nautical miles), the nearby Atlantic Intracoastal Waterway and its tributaries a no-discharge zone (NDZ) to alleviate the human fecal pollution. The Town garnered supporting resolutions from other local communities who jointly petitioned the North Carolina Department of Environmental and Natural Resources. This State regulatory agency supported the local government resolutions and sent an application for an NDZ to the EPA in April 2009. The EPA concurred, and in February 2010 the coastal waters of New Hanover County, NC, became the first marine area on the U.S. eastern seaboard between Delaware and the Florida Keys to be declared a no-discharge zone. Copyright © 2010 Elsevier Ltd. All rights reserved.

Heavy metal contamination in river water and sediments of the Swarnamukhi River Basin, India: risk assessment and environmental implications.

PubMed

Patel, Priyanka; Raju, N Janardhana; Reddy, B C Sundara Raja; Suresh, U; Sankar, D B; Reddy, T V K

2018-04-01

The concentration of heavy metals was analyzed each of 20 river water, suspended sediments and bed sediments along the stretch of Swarnamukhi River Basin. River water is not contaminated with heavy metals except Fe and Mn. Contamination factor in sediments shows considerable to very high degree contamination with Cr, Cu, Pb and Zn. The sources of these metals could be residential wastes, sewer outfall, fertilizers, pesticides (M-45 + carbondine) and traffic activities apart from natural weathering of granitic rocks present in the basin area. Principal component analyses indicate the interaction between metals in different media. The comparison of metals (Cu, Pb and Zn) in bed sediments of Swarnamukhi River with the Indian and world averages indicates that the values obtained in the basin are above the Indian averages and far below to the world averages. Average shale values and sediment quality guidelines point toward the enrichment and contamination of Cu, Cr, Pb and Zn to several fold leading to eco-toxicological risks in basin.

Determination of the origin of groundwater nitrate at an air weapons range using the dual isotope approach.

PubMed

Bordeleau, Geneviève; Savard, Martine M; Martel, Richard; Ampleman, Guy; Thiboutot, Sonia

2008-06-06

Nitrate is one of the most common contaminants in shallow groundwater, and many sources may contribute to the nitrate load within an aquifer. Groundwater nitrate plumes have been detected at several ammunition production sites. However, the presence of multiple potential sources and the lack of existing isotopic data concerning explosive degradation-induced nitrate constitute a limitation when it comes to linking both types of contaminants. On military training ranges, high nitrate concentrations in groundwater were reported for the first time as part of the hydrogeological characterization of the Cold Lake Air Weapons Range (CLAWR), Alberta, Canada. Explosives degradation is thought to be the main source of nitrate contamination at CLAWR, as no other major source is present. Isotopic analyses of N and O in nitrate were performed on groundwater samples from the unconfined and confined aquifers; the dual isotopic analysis approach was used in order to increase the chances of identifying the source of nitrate. The isotopic ratios for the groundwater samples with low nitrate concentration suggested a natural origin with a strong contribution of anthropogenic atmospheric NOx. For the samples with nitrate concentration above the expected background level the isotopic ratios did not correspond to any source documented in the literature. Dissolved RDX samples were degraded in the laboratory and results showed that all reproduced degradation processes released nitrate with a strong fractionation. Laboratory isotopic values for RDX-derived NO(3)(-) produced a trend of high delta(18)O-low delta(15)N to low delta(18)O-high delta(15)N, and groundwater samples with nitrate concentrations above the expected background level appeared along this trend. Our results thus point toward a characteristic field of isotopic ratios for nitrate being derived from the degradation of RDX.

The quality of our Nation's waters: factors affecting public-supply-well vulnerability to contamination: understanding observed water quality and anticipating future water quality

USGS Publications Warehouse

Eberts, Sandra M.; Thomas, Mary Ann; Jagucki, Martha L.

2013-01-01

As part of the U.S. Geological Survey National Water-Quality Assessment (NAWQA) Program, a study was conducted from 2001 to 2011 to shed light on factors that affect the vulnerability of water from public-supply wells to contamination (referred to hereafter as “public-supply-well vulnerability”). The study was designed as a follow-up to earlier NAWQA studies that found mixtures of contaminants at low concentrations in groundwater near the water table in urban areas across the Nation and, less frequently, in deeper groundwater typically used for public supply. Beside the factors affecting public-supply-well vulnerability to contamination, this circular describes measures that can be used to determine which factor (or factors) plays a dominant role at an individual public-supply well. Case-study examples are used throughout to show how such information can be used to improve water quality. In general, the vulnerability of the water from public-supply wells to contamination is a function of contaminant input within the area that contributes water to a well, the mobility and persistence of a contaminant once released to the groundwater, and the ease of groundwater and contaminant movement from the point of recharge to the open interval of a well. The following measures described in this circular are particularly useful for indicating which contaminants in an aquifer might reach an individual public-supply well and when, how, and at what concentration they might arrive: * Sources of recharge—Information on the sources of recharge for a well provides insight into contaminants that might enter the aquifer with the recharge water and potentially reach the well. * Geochemical conditions—Information on the geochemical conditions encountered by groundwater traveling to a well provides insight into contaminants that might persist in the water all the way to the well. * Groundwater-age mixtures—Information on the ages of the different waters that mix in a well provides insight into the time lag between contaminant input at the water table and contaminant arrival at the well. It also provides insight into the potential for in-well dilution of contaminated water by unaffected groundwater of a different age that simultaneously enters the well. Preferential flow pathways—pathways that provide little resistance to flow—can influence how all other factors affect public-supply-well vulnerability to contamination. For example, preferential flow pathways can influence whether a contaminant source is physically linked to a well, whether contaminant concentrations are substantially altered before contaminated groundwater reaches a well, and whether contaminated groundwater can arrive at a well within a timeframe of concern to the well owner. Methods for recognizing the influence of preferential flow pathways on the quality of water from a public-supply well are presented in this circular and can provide opportunities to prevent or mitigate the deterioration of a water supply. Knowing what water-quality variables to measure, what spatial and temporal scales on which to measure them, and how to interpret the resulting data makes it possible for samples from public-supply wells to provide a broad window into a well’s past and present water quality—and possibly future water quality. Such insight can enable resource managers to prioritize actions for sustaining a high-quality groundwater source of drinking water.

The influence of the scale of mining activity and mine site remediation on the contamination legacy of historical metal mining activity.

PubMed

Bird, Graham

2016-12-01

Globally, thousands of kilometres of rivers are degraded due to the presence of elevated concentrations of potentially harmful elements (PHEs) sourced from historical metal mining activity. In many countries, the presence of contaminated water and river sediment creates a legal requirement to address such problems. Remediation of mining-associated point sources has often been focused upon improving river water quality; however, this study evaluates the contaminant legacy present within river sediments and attempts to assess the influence of the scale of mining activity and post-mining remediation upon the magnitude of PHE contamination found within contemporary river sediments. Data collected from four exemplar catchments indicates a strong relationship between the scale of historical mining, as measured by ore output, and maximum PHE enrichment factors, calculated versus environmental quality guidelines. The use of channel slope as a proxy measure for the degree of channel-floodplain coupling indicates that enrichment factors for PHEs in contemporary river sediments may also be the highest where channel-floodplain coupling is the greatest. Calculation of a metric score for mine remediation activity indicates no clear influence of the scale of remediation activity and PHE enrichment factors for river sediments. It is suggested that whilst exemplars of significant successes at improving post-remediation river water quality can be identified; river sediment quality is a much more long-lasting environmental problem. In addition, it is suggested that improvements to river sediment quality do not occur quickly or easily as a result of remediation actions focused a specific mining point sources. Data indicate that PHEs continue to be episodically dispersed through river catchments hundreds of years after the cessation of mining activity, especially during flood flows. The high PHE loads of flood sediments in mining-affected river catchments and the predicted changes to flood frequency, especially, in many river catchments, provides further evidence of the need to enact effective mine remediation strategies and to fully consider the role of river sediments in prolonging the environmental legacy of historical mine sites.

The association between domestic animal presence and ownership and household drinking water contamination among peri-urban communities of Kisumu, Kenya.

PubMed

Barnes, Amber N; Anderson, John D; Mumma, Jane; Mahmud, Zahid Hayat; Cumming, Oliver

2018-01-01

Household drinking water can be contaminated by diarrheagenic enteropathogens at numerous points between the source and actual consumption. Interventions to prevent this contamination have focused on preventing exposure to human waste through interventions to improve drinking water, sanitation and hygiene (WASH). In many cases though, the infectious agent may be of zoonotic rather than human origin suggesting that unsafely managed animal waste may contribute to the contamination of household drinking water and the associated diarrheal disease burden. A cross-sectional household survey of 800 households was conducted across three informal peri-urban neighborhoods of Kisumu, Kenya, collecting stored drinking water samples, administering a household survey including water, sanitation and hygiene infrastructure and behaviors, and recording domestic animal presence and ownership. We used multivariate logistic regression to assess the association of traditional WASH factors and domestic animal presence and ownership on microbial contamination of household drinking water. The majority of households sampled had fecally contaminated drinking water (67%), defined by the presence of any colony forming units of the fecal indicator bacteria enterococci. After adjustment for potential confounders, including socio-economic status and water and sanitation access, both household animal ownership (aOR 1.31; CI 1.00-1.73, p = 0.05) and the presence of animal waste in the household compound (aOR 1.38; CI 1.01, 1.89, p = 0.04) were found to be significantly associated with household drinking water contamination. None of the conventional WASH variables were found to be significantly associated with household drinking water contamination in the study population. Water, sanitation, and hygiene strategies to reduce diarrheal disease should consider the promotion of safe animal contact alongside more traditional interventions focusing on the management of human waste. Future research on fecal contamination of unsafe household drinking water should utilize host-specific markers to determine whether the source is human or animal to prepare targeted public health messages.

The association between domestic animal presence and ownership and household drinking water contamination among peri-urban communities of Kisumu, Kenya

PubMed Central

Mumma, Jane; Mahmud, Zahid Hayat

2018-01-01

Introduction Household drinking water can be contaminated by diarrheagenic enteropathogens at numerous points between the source and actual consumption. Interventions to prevent this contamination have focused on preventing exposure to human waste through interventions to improve drinking water, sanitation and hygiene (WASH). In many cases though, the infectious agent may be of zoonotic rather than human origin suggesting that unsafely managed animal waste may contribute to the contamination of household drinking water and the associated diarrheal disease burden. Methods A cross-sectional household survey of 800 households was conducted across three informal peri-urban neighborhoods of Kisumu, Kenya, collecting stored drinking water samples, administering a household survey including water, sanitation and hygiene infrastructure and behaviors, and recording domestic animal presence and ownership. We used multivariate logistic regression to assess the association of traditional WASH factors and domestic animal presence and ownership on microbial contamination of household drinking water. Results The majority of households sampled had fecally contaminated drinking water (67%), defined by the presence of any colony forming units of the fecal indicator bacteria enterococci. After adjustment for potential confounders, including socio-economic status and water and sanitation access, both household animal ownership (aOR 1.31; CI 1.00–1.73, p = 0.05) and the presence of animal waste in the household compound (aOR 1.38; CI 1.01, 1.89, p = 0.04) were found to be significantly associated with household drinking water contamination. None of the conventional WASH variables were found to be significantly associated with household drinking water contamination in the study population. Conclusions Water, sanitation, and hygiene strategies to reduce diarrheal disease should consider the promotion of safe animal contact alongside more traditional interventions focusing on the management of human waste. Future research on fecal contamination of unsafe household drinking water should utilize host-specific markers to determine whether the source is human or animal to prepare targeted public health messages. PMID:29874284

Contamination of environment in the road surroudings - impact of road salting on Norway spruce (Picea abies) and Scots pine (Pinus sylvestris)

NASA Astrophysics Data System (ADS)

Hegrová, Jitka; Steiner, Oliver; Goessler, Walter; Tanda, Stefan; Anděl, Petr

2017-09-01

A comprehensive overview of the influence of transport on the environment is presented in this study. The complex analysis of soil and needle samples provides an extensive set of data, which presents elemental contamination of the environment near roads. Traffic pollution (including winter road treatment) has a significant negative influence on our environment. Besides sodium and chlorine from winter maintenance many other elements are emitted into the environment. Three possible sources of contamination are assumed for environmental contamination evaluation: car emission, winter maintenance and abrasion from breaks and clutches. The chemical analysis focused on the description of samples from inorganic point of view. The influence of the contamination potential on the sodium and chlorine content in the samples of 1st year-old and 2nd year-old needles of Norway spruce (Picea abies) and Scots pine (Pinus sylvestris) is discussed. Additional soil samples were taken from each sampling site and analyzed to get insight in the sodium and chlorine distribution. Statistical evaluation was used for interpretation of complex interaction patterns between element concentrations in different aged needles based on localities character including distance from the road and element concentration in soils. This species of needles were chosen because of its heightened sensitivity towards salinization. The study was conducted in different parts of the Czech Republic. The resulting database is a source of valuable information about the influence of transport on the environment.

A critical evaluation of two point-of-use water treatment technologies: can they provide water that meets WHO drinking water guidelines?

PubMed

Murphy, Heather M; McBean, Edward A; Farahbakhsh, Khosrow

2010-12-01

Point-of-use (POU) technologies have been proposed as solutions for meeting the Millennium Development Goal (MDG) for safe water. They reduce the risk of contamination between the water source and the home, by providing treatment at the household level. This study examined two POU technologies commonly used around the world: BioSand and ceramic filters. While the health benefits in terms of diarrhoeal disease reduction have been fairly well documented for both technologies, little research has focused on the ability of these technologies to treat other contaminants that pose health concerns, including the potential for formation of contaminants as a result of POU treatment. These technologies have not been rigorously tested to see if they meet World Health Organization (WHO) drinking water guidelines. A study was developed to evaluate POU BioSand and ceramic filters in terms of microbiological and chemical quality of the treated water. The following parameters were monitored on filters in rural Cambodia over a six-month period: iron, manganese, fluoride, nitrate, nitrite and Escherichia coli. The results revealed that these technologies are not capable of consistently meeting all of the WHO drinking water guidelines for these parameters.

A comprehensive analysis of heavy metals in urban road dust of Xi'an, China: Contamination, source apportionment and spatial distribution.

PubMed

Pan, Huiyun; Lu, Xinwei; Lei, Kai

2017-12-31

A detailed investigation was conducted to study heavy metal contamination in road dust from four regions of Xi'an, Northwest China. The concentrations of eight heavy metals Co, Cr, Cu, Mn, Ni, Pb, Zn and V were determined by X-Ray Fluorescence. The mean concentrations of these elements were: 30.9mgkg -1 Co, 145.0mgkg -1 Cr, 54.7mgkg -1 Cu, 510.5mgkg -1 Mn, 30.8mgkg -1 Ni, 124.5mgkg -1 Pb, 69.6mgkg -1 V and 268.6mgkg -1 Zn. There was significant enrichment of Pb, Zn, Co, Cu and Cr based on geo-accumulation index value. Multivariate statistical analysis showed that levels of Cu, Pb, Zn, Co and Cr were controlled by anthropogenic activities, while levels of Mn, Ni and V were associated with natural sources. Principle component analysis and multiple linear regression were applied to determine the source apportionment. The results showed that traffic was the main source with a percent contribution of 53.4%. Natural sources contributed 26.5%, and other anthropogenic pollution sources contributed 20.1%. Clear heavy metal pollution hotspots were identified by GIS mapping. The location of point pollution sources and prevailing wind direction were found to be important factors in the spatial distribution of heavy metals. Copyright © 2017 Elsevier B.V. All rights reserved.

Determining sources of water and contaminants to wells in a carbonate aquifer near Martinsburg, Blair County, Pennsylvania, by use of geochemical indicators, analysis of anthropogenic contaminants, and simulation of ground-water flow

USGS Publications Warehouse

Lindsey, Bruce D.; Koch, Michele L.

2004-01-01

Water supply for the Borough of Martinsburg, Pa., is from two well fields (Wineland and Hershberger) completed in carbonate-bedrock aquifers in the Morrison Cove Valley. Water supply is plentiful; however, waters with high concentrations of nitrate are a concern. This report describes the sources of water and contaminants to the supply wells. A review of previous investigations was used to establish the aquifer framework and estimate aquifer hydraulic properties. Aquifer framework and simulation of ground-water flow in a 25-square-mile area using the MODFLOW model helped to further constrain aquifer hydraulic properties and identify water-source areas in the zone of contribution of ground water to the well fields. Flow simulation identified potential contaminant-source areas. Data on contaminants and geochemical characteristics of ground water at the well fields were compared to the results of flow simulation. The Woodbury Anticline controls the aquifer framework near the well fields and four carbonate-bedrock formations contain the primary aquifers. Three carbonate-bedrock aquifers of Ordovician age overlie the Gatesburg aquifer of Cambrian age on the flanks of the anticline. Fracture, not conduit, permeability was determined to be the dominant water-bearing characteristic of the bedrock. The horizontal hydraulic conductivity of the Gatesburg aquifer is about 36 feet per day. The other carbonate aquifers (Nittany/Stonehenge, Bellefonte/Axemann, and Coburn through Loysburg aquifers) overlying and flanking the Gatesburg aquifer have horizontal hydraulic conductivities of about 1 foot per day. Regional directions of ground-water flow are toward the major streams with Clover Creek as the major discharge point for ground water in the east. Ground-water flow to the well fields is anisotropic with a 5:1 preferential horizontal direction along strike of the axial fold of the anticline. Thus, the zone of contribution of ground water to the well fields is elongate in a north-south direction along the anticline axis, with the majority of the flow to the well fields originating from the south. Human activity in the areal extent of the zone of contribution to the well fields was the source of contaminants. The areal extent of the zone of contribution included both urban areas in the Borough and a large amount of agricultural land. By relating results of flow simulation, natural geochemistry, and analyses of anthropogenic (human-made) contaminants, the source areas for water and contaminants were determined with more confidence than by using only flow simulation. Analysis of natural geochemistry identified water sources from both limestone and dolomite aquifers. Geochemistry results also indicated fractures, not conduits, were the dominant source of water from aquifers; however, quantitative source identification was not possible. Chemical ratios of chloride and bromide were useful to show that all samples of ground water had sources with chemical contributions from land surface. Nitrogen isotope ratio analysis indicated animal manure as the possible primary source of nitrate in most ground water. Some of the nitrate in ground water had chemical fertilizer as a source. At the Wineland well field, chemical fertilizer was likely the source of nitrate. The nitrate in water from the Hershberger well field was from a mixture of fertilizer and animal-manure sources. Human sewage was ruled out as a major source of nitrate in water from the municipal wells by results showing 1) wastewater compounds in sewage were rarely detected and 2) a mass-balance calculation indicating the small contribution of nitrogen that could be attributed to septic systems.

Fingerprinting two metal contaminants in streams with Cu isotopes near the Dexing Mine, China.

PubMed

Song, Shiming; Mathur, Ryan; Ruiz, Joaquin; Chen, Dandan; Allin, Nicholas; Guo, Kunyi; Kang, Wenkai

2016-02-15

Transition metal isotope signatures are becoming useful for fingerprinting sources in surface waters. This study explored the use of Cu isotope values to trace dissolved metal contaminants in stream water throughout a watershed affected by mining by-products of the Dexing Mine, the largest porphyry Cu operation in Asia. Cu isotope values of stream water were compared to potential mineral sources of Cu in the mining operation, and to proximity to the known Cu sources. The first mineral source, chalcopyrite, CuFeS2 has a 'tight' cluster of Cu isotope values (-0.15‰ to +1.65‰; +0.37 ± 0.6‰, 1σ, n=10), and the second mineral source, pyrite (FeS2), has a much larger range of Cu isotope values (-4‰ to +11.9‰; 2.7 ± 4.3‰, 1σ, n=16). Dissolved Cu isotope values of stream water indicated metal derived from either chalcopyrite or pyrite. Above known Cu mineralization, stream waters are approximately +1.5‰ greater than the average chalcopyrite and are interpreted as derived from weathering of chalcopyrite. In contrast, dissolved Cu isotope values in stream water emanating from tailings piles had Cu isotope values similar to or greater than pyrite (>+6‰, a common mineral in the tailings). These values are interpreted as sourced from the tailings, even in solutions that possess significantly lower concentrations of Cu (<0.05 ppm). Elevated Cu isotope values were also found in two soil and two tailings samples (δ(65)Cu ranging between +2 to +5‰). These data point to the mineral pyrite in tailings as the mineral source for the elevated Cu isotope values. Therefore, Cu isotope values of waters emanating from a clearly contaminated drainage possess different Cu isotope values, permitting the discrimination of Cu derived from chalcopyrite and pyrite in solution. Data demonstrate the utility of Cu isotopic values in waters, minerals, and soils to fingerprint metallic contamination for environmental problems. Copyright © 2015 Elsevier B.V. All rights reserved.

Quantitative FE-EPMA measurement of formation and inhibition of carbon contamination on Fe for trace carbon analysis.

PubMed

Tanaka, Yuji; Yamashita, Takako; Nagoshi, Masayasu

2017-04-01

Hydrocarbon contamination introduced during point, line and map analyses in a field emission electron probe microanalysis (FE-EPMA) was investigated to enable reliable quantitative analysis of trace amounts of carbon in steels. The increment of contamination on pure iron in point analysis is proportional to the number of iterations of beam irradiation, but not to the accumulated irradiation time. A combination of a longer dwell time and single measurement with a liquid nitrogen (LN2) trap as an anti-contamination device (ACD) is sufficient for a quantitative point analysis. However, in line and map analyses, contamination increases with irradiation time in addition to the number of iterations, even though the LN2 trap and a plasma cleaner are used as ACDs. Thus, a shorter dwell time and single measurement are preferred for line and map analyses, although it is difficult to eliminate the influence of contamination. While ring-like contamination around the irradiation point grows during electron-beam irradiation, contamination at the irradiation point increases during blanking time after irradiation. This can explain the increment of contamination in iterative point analysis as well as in line and map analyses. Among the ACDs, which are tested in this study, specimen heating at 373 K has a significant contamination inhibition effect. This technique makes it possible to obtain line and map analysis data with minimum influence of contamination. The above-mentioned FE-EPMA data are presented and discussed in terms of the contamination-formation mechanisms and the preferable experimental conditions for the quantification of trace carbon in steels. © The Author 2016. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Multicenter Outbreak of Infections by Saprochaete clavata, an Unrecognized Opportunistic Fungal Pathogen

PubMed Central

Vaux, Sophie; Criscuolo, Alexis; Desnos-Ollivier, Marie; Diancourt, Laure; Tarnaud, Chloé; Vandenbogaert, Matthias; Brisse, Sylvain; Coignard, Bruno; Garcia-Hermoso, Dea; Blanc, Catherine; Hoinard, Damien; Lortholary, Olivier; Bretagne, Stéphane; Thiolet, Jean-Michel; de Valk, Henriette; Courbil, Rémi; Chabanel, Anne; Simonet, Marion; Maire, Francoise; Jbilou, Saadia; Tiberghien, Pierre; Blanchard, Hervé; Venier, Anne-Gaëlle; Bernet, Claude; Simon, Loïc; Sénéchal, Hélène; Pouchol, Elodie; Angot, Christiane; Ribaud, Patricia; Socié, G.; Flèche, M.; Brieu, Nathalie; Lagier, Evelyne; Chartier, Vanessa; Allegre, Thierry; Maulin, Laurence; Lanic, Hélène; Tilly, Hervé; Bouchara, Jean-Philippe; Pihet, Marc; Schmidt, Aline; Kouatchet, Achille; Vandamme, Yves-Marie; Ifrah, Norbert; Mercat, Alain; Accoceberry, Isabelle; Albert, Olivier; Leguay, Thibaut; Rogues, Anne-Marie; Bonhomme, Julie; Reman, Oumédaly; Lesteven, Claire; Poirier, Philippe; Chabrot, Cécile Molucon; Calvet, Laure; Baud, Olivier; Cambon, Monique; Farkas, Jean Chistophe; Lafon, Bruno; Dalle, Frédéric; Caillot, Denis; Lazzarotti, Aline; Aho, Serge; Combret, Sandrine; Facon, Thierry; Sendid, Boualem; Loridant, Séverine; Louis, Terriou; Cazin, Bruno; Grandbastien, Bruno; Bourgeois, Nathalie; Lotthé, Anne; Cartron, Guillaume; Ravel, Christophe; Colson, Pascal; Gaudard, Philippe; Bonmati, Caroline; Simon, Loic; Rabaud, Christian; Machouart, Marie; Poisson, Didier; Carp, Diana; Meunier, Jérôme; Gaschet, Anne; Miquel, Chantal; Sanhes, Laurence; Ferreyra, Milagros; Leibinger, Franck; Geudet, Philippe; Toubas, Dominique; Himberlin, Chantal; Bureau-Chalot, Florence; Delmer, Alain; Favennec, Loïc; Gargala, Gilles; Michot, Jean-Baptiste; Girault, Christophe; David, Marion; Leprêtre, Stéphane; Jardin, Fabrice; Honderlick, Pierre; Caille, Vincent; Cerf, Charles; Cassaing, Sophie; Recher, Christian; Picard, Muriel; Protin, Caroline; Huguet, Françoise; Huynh, Anne; Ruiz, Jean; Riu-Poulenc, Béatrice; Letocart, Philippe; Marchou, Bruno; Verdeil, Xavier; Cavalié, Laurent; Chauvin, Pamela; Iriart, Xavier; Valentin, Alexis; Bouvet, Emmanuelle; Delmas-Marsalet, Béatrice; Jeblaoui, Asma; Kassis-Chikhani, Najiby; Mühlethaler, Konrad; Zimmerli, Stefan; Zalar, Polona; Sánchez-Reus, Ferran; Gurgui, Merce

2014-01-01

ABSTRACT Rapidly fatal cases of invasive fungal infections due to a fungus later identified as Saprochaete clavata were reported in France in May 2012. The objectives of this study were to determine the clonal relatedness of the isolates and to investigate possible sources of contamination. A nationwide alert was launched to collect cases. Molecular identification methods, whole-genome sequencing (WGS), and clone-specific genotyping were used to analyze recent and historical isolates, and a case-case study was performed. Isolates from thirty cases (26 fungemias, 22 associated deaths at day 30) were collected between September 2011 and October 2012. Eighteen cases occurred within 8 weeks (outbreak) in 10 health care facilities, suggesting a common source of contamination, with potential secondary cases. Phylogenetic analysis identified one clade (clade A), which accounted for 16/18 outbreak cases. Results of microbiological investigations of environmental, drug, or food sources were negative. Analysis of exposures pointed to a medical device used for storage and infusion of blood products, but no fungal contamination was detected in the unused devices. Molecular identification of isolates from previous studies demonstrated that S. clavata can be found in dairy products and has already been involved in monocentric outbreaks in hematology wards. The possibility that S. clavata may transmit through contaminated medical devices or can be associated with dairy products as seen in previous European outbreaks is highly relevant for the management of future outbreaks due to this newly recognized pathogen. This report also underlines further the potential of WGS for investigation of outbreaks due to uncommon fungal pathogens. PMID:25516620

Assessment of sources of human pathogens and fecal contamination in a Florida freshwater lake.

PubMed

Staley, Christopher; Reckhow, Kenneth H; Lukasik, Jerzy; Harwood, Valerie J

2012-11-01

We investigated the potential for a variety of environmental reservoirs to harbor or contribute fecal indicator bacteria (FIB), DNA markers of human fecal contamination, and human pathogens to a freshwater lake. We hypothesized that submerged aquatic vegetation (SAV), sediments, and stormwater act as reservoirs and/or provide inputs of FIB and human pathogens to this inland water. Analysis included microbial source tracking (MST) markers of sewage contamination (Enterococcus faecium esp gene, human-associated Bacteroides HF183, and human polyomaviruses), pathogens (Salmonella, Cryptosporidium, Giardia, and enteric viruses), and FIB (fecal coliforms, Escherichia coli, and enterococci). Bayesian analysis was used to assess relationships among microbial and physicochemical variables. FIB in the water were correlated with concentrations in SAV and sediment. Furthermore, the correlation of antecedent rainfall and major rain events with FIB concentrations and detection of human markers and pathogens points toward multiple reservoirs for microbial contaminants in this system. Although pathogens and human-source markers were detected in 55% and 21% of samples, respectively, markers rarely coincided with pathogen detection. Bayesian analysis revealed that low concentrations (<45 CFU × 100 ml(-1)) of fecal coliforms were associated with 93% probability that pathogens would not be detected; furthermore the Bayes net model showed associations between elevated temperature and rainfall with fecal coliform and enterococci concentrations, but not E. coli. These data indicate that many under-studied matrices (e.g. SAV, sediment, stormwater) are important reservoirs for FIB and potentially human pathogens and demonstrate the usefulness of Bayes net analysis for water quality assessment. Copyright © 2012 Elsevier Ltd. All rights reserved.

Atmospheric lead deposition to Okefenokee Swamp, Georgia, USA

USGS Publications Warehouse

Jackson, B.P.; Winger, P.V.; Lasier, P.J.

2004-01-01

'Capsule:' Coal combustion emissions appear to be a major source of Pb in the Okefenokee wetland. Contamination of the environment from atmospheric deposition during the twentieth century is pervasive even in areas ostensibly considered pristine or remote from point sources. In this study, Pb concentrations in a Pb-210-dated peat core collected from the Okefenokee Swamp, GA were used to assess historical contaminant input via atmospheric deposition. Lead isotope ratios were determined by dynamic reaction cell ICP-MS (DRC-ICP-MS). Increases in Pb concentration occurred in the late nineteenth century and a marked rise in Pb concentrations pre-dated the widespread use of leaded gasoline within the US. The Pb-206/Pb-207 ratios of 1.19 during this period were consistent with coal combustion emissions. A later increase in Pb concentration, concurrent with a trend toward more radiogenic Pb-206/Pb-207 ratios in gasoline is consistent with an increased input of Pb from leaded gasoline emissions. However, it appears that coal combustion emissions remain a major source of Pb to the Okefenokee.

Effect of lixiviated sediments affected with treated water on Selenastrum capricornutum, Printz and Origanum vulgare L.

PubMed

Ramos, Guadalupe E; Lopez, Martin H; Flores, Antonio M; Figueroa, Guadalupe T; De Leon, Fernando G

2010-01-01

Xochimilco is an area of Mexico City fulfilling important ecological functions. However, the water of the canal network in the lacustrine zone of Xochimilco is supplied by the water treatment plants of the city, implying a risk of accumulated contaminants in the sediments. This study reports the effect of lixiviates obtained from sediments collected in the canals of Xochimilco on the growth of the alga Selenastrum capricornutum and the angiosperm Origanum vulgare. Three factors were tested: (a) water source in terms of the effluent from the two water treatment plants (urban waste-water, located at Cerro de la Estrella (CE) and urban-rural waters at San Luis Tlaxialtemalco (SLT); (b) sampling season (January, dry season; May and September, rainy season; and (c) distances from the water discharge point in the Xochimilco's main canal (5200 and 1000 m for CE, and 0, 200 m for SLT). The chemical water properties analyzed were: pH, electrical conductivity, N-NO(3), N-NH(3), N(Total), P-PO(4) and P(Total). The alga was more sensitive to the contaminants than O. vulgare, showing growth inhibition of 93-100%. The effect of sampling season on the inhibition of algal growth was ordered as follows: September > May > January. Lixiviates obtained from sediment samples 200 and 1000 m from the main point of water discharge caused a higher algal growth inhibition than the samples obtained at the source point. Lixiviate promoted the growth of seedlings of O. vulgare.

On the construction, comparison, and variability of airsheds for interpreting semivolatile organic compounds in passively sampled air.

PubMed

Westgate, John N; Wania, Frank

2011-10-15

Air mass origin as determined by back trajectories often aids in explaining some of the short-term variability in the atmospheric concentrations of semivolatile organic contaminants. Airsheds, constructed by amalgamating large numbers of back trajectories, capture average air mass origins over longer time periods and thus have found use in interpreting air concentrations obtained by passive air samplers. To explore some of their key characteristics, airsheds for 54 locations on Earth were constructed and compared for roundness, seasonality, and interannual variability. To avoid the so-called "pole problem" and to simplify the calculation of roundness, a "geodesic grid" was used to bin the back-trajectory end points. Departures from roundness were seen to occur at all latitudes and to correlate significantly with local slope but no strong relationship between latitude and roundness was revealed. Seasonality and interannual variability vary widely enough to imply that static models of transport are not sufficient to describe the proximity of an area to potential sources of contaminants. For interpreting an air measurement an airshed should be generated specifically for the deployment time of the sampler, especially when investigating long-term trends. Samples taken in a single season may not represent the average annual atmosphere, and samples taken in linear, as opposed to round, airsheds may not represent the average atmosphere in the area. Simple methods are proposed to ascertain the significance of an airshed or individual cell. It is recommended that when establishing potential contaminant source regions only end points with departure heights of less than ∼700 m be considered.

Theoretical study on the effect of the design of small (milli-Newton) thruster jets on molecular contamination for the space station

NASA Technical Reports Server (NTRS)

Riley, B. R.

1986-01-01

The self-induced molecular contamination around the space station could have adverse effects on space station components (for example solar panels) as well as scientific experiments that might be done on or near the space station. Aerospace engineers need to design a space station (SS) propulsion system that keeps the SS in a stable orbit and at the same time does not allow the propellant gases to interfere with the experiments of the user. One scenario that might accomplish the above requirements is to use an electrothermal propulsion system, resistojet, that will thrust continuously in the hundreds of milli-Newton range which will provide a constant altitude for the SS with a low g environment. As a first attempt to understand the contamination from such a propulsion system, a point source model was developed. The numerical results of the point source model are given. Number column densities for CO2 are presented as a function of direction of observation (line of sight), temperature of the exit gas, and mean exit velocity. All the results are for a constant exhaust rate of 5,000 kg/year. In addition, a mathematical model to study the effect of nozzle design on the induced molecular environment around the space station produced by simple gas propellants is described. The mathematical model would allow one to follow the expansion of the gas from the throat of a nozzle to the nozzle exit plane and then into the space external to the nozzle.

First-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Foreground Emission

NASA Astrophysics Data System (ADS)

Bennett, C. L.; Hill, R. S.; Hinshaw, G.; Nolta, M. R.; Odegard, N.; Page, L.; Spergel, D. N.; Weiland, J. L.; Wright, E. L.; Halpern, M.; Jarosik, N.; Kogut, A.; Limon, M.; Meyer, S. S.; Tucker, G. S.; Wollack, E.

2003-09-01

The WMAP mission has mapped the full sky to determine the geometry, content, and evolution of the universe. Full-sky maps are made in five microwave frequency bands to separate the temperature anisotropy of the cosmic microwave background (CMB) from foreground emission, including diffuse Galactic emission and Galactic and extragalactic point sources. We define masks that excise regions of high foreground emission, so CMB analyses can be carried out with minimal foreground contamination. We also present maps and spectra of the individual emission components, leading to an improved understanding of Galactic astrophysical processes. The effectiveness of template fits to remove foreground emission from the WMAP data is also examined. These efforts result in a CMB map with minimal contamination and a demonstration that the WMAP CMB power spectrum is insensitive to residual foreground emission. We use a maximum entropy method to construct a model of the Galactic emission components. The observed total Galactic emission matches the model to less than 1%, and the individual model components are accurate to a few percent. We find that the Milky Way resembles other normal spiral galaxies between 408 MHz and 23 GHz, with a synchrotron spectral index that is flattest (βs~-2.5) near star-forming regions, especially in the plane, and steepest (βs~-3) in the halo. This is consistent with a picture of relativistic cosmic-ray electron generation in star-forming regions and diffusion and convection within the plane. The significant synchrotron index steepening out of the plane suggests a diffusion process in which the halo electrons are trapped in the Galactic potential long enough to suffer synchrotron and inverse Compton energy losses and hence a spectral steepening. The synchrotron index is steeper in the WMAP bands than in lower frequency radio surveys, with a spectral break near 20 GHz to βs<-3. The modeled thermal dust spectral index is also steep in the WMAP bands, with βd~2.2. Our model is driven to these conclusions by the low level of total foreground contamination at ~60 GHz. Microwave and Hα measurements of the ionized gas agree well with one another at about the expected levels. Spinning dust emission is limited to <~5% of the Ka-band foreground emission, assuming a thermal dust distribution with a cold neutral medium spectrum and a monotonically decreasing synchrotron spectrum. A catalog of 208 point sources is presented. The reliability of the catalog is 98%; i.e., we expect five of the 208 sources to be statistically spurious. The mean spectral index of the point sources is α~0 (β~-2). Derived source counts suggest a contribution to the anisotropy power from unresolved sources of (15.0+/-1.4)×10-3 μK2 sr at Q band and negligible levels at V band and W band. The Sunyaev-Zeldovich effect is shown to be a negligible ``contamination'' to the maps. WMAP is the result of a partnership between Princeton University and the NASA Goddard Space Flight Center. Scientific guidance is provided by the WMAP Science Team.

Contamination sources, prevention, and research

USDA-ARS?s Scientific Manuscript database

Contamination is defined as anything other than cotton in cotton lint. Worldwide, contamination is on the rise and plastic contamination has increased at a faster rate than contamination overall. In the U.S., there are many sources of plastic contaminants, such as plastic trash that collects in cott...

Associations of free-living bacteria and dissolved organic compounds in a plume of contaminated groundwater

USGS Publications Warehouse

Harvey, R.W.; Barber, L.B.; ,

1992-01-01

Associations of free-living bacteria (FLB) and dissolved organic contaminants in a 4-km-long plume of sewage-contaminated groundwater were investigated. Abundance of FLB in the core of the plume (as delineated by maximum specific conductance) steadily decreased in the direction of flow from a point 0.25 km downgradient from the source to the toe of the plume. At 0.25 km downgradient, FLB comprised up to 31% of the total bacterial population, but constituted < 7% of the population at 2 km downgradient. Abundance of FLB correlated strongly (r = 0.80 n = 23) with total dissolved organic carbon (DOC) in contaminated groundwater between 0.64 and 2.1 km downgradient, although distributions of individual contaminants such as di-, tri- and tetrachloroethene were highly variable, and their association with FLB less clear. Numbers of FLB in the downgradient portion of the plume which is contaminated with branched-chain alkylbenzenesulfonate (ABS) surfactants were low (< 5??108/L) in spite of relatively high levels of DOC (up to 4 mg/L). However, abundance of FLB correlated strongly with non-surfactant DOC along vertical transects through the plume. The ratio of FLB to DOC and the ratio of FLB to attached bacteria generally decreased in the direction of flow and, consequently, with the age of the organic contaminants.

Water Quality, Sanitation, and Hygiene Conditions in Schools and Households in Dolakha and Ramechhap Districts, Nepal: Results from A Cross-Sectional Survey.

PubMed

Shrestha, Akina; Sharma, Subodh; Gerold, Jana; Erismann, Séverine; Sagar, Sanjay; Koju, Rajendra; Schindler, Christian; Odermatt, Peter; Utzinger, Jürg; Cissé, Guéladio

2017-01-18

This study assessed drinking water quality, sanitation, and hygiene (WASH) conditions among 708 schoolchildren and 562 households in Dolakha and Ramechhap districts of Nepal. Cross-sectional surveys were carried out in March and June 2015. A Delagua water quality testing kit was employed on 634 water samples obtained from 16 purposively selected schools, 40 community water sources, and 562 households to examine water quality. A flame atomic absorption spectrophotometer was used to test lead and arsenic content of the same samples. Additionally, a questionnaire survey was conducted to obtain WASH predictors. A total of 75% of school drinking water source samples and 76.9% point-of-use samples (water bottles) at schools, 39.5% water source samples in the community, and 27.4% point-of-use samples at household levels were contaminated with thermo-tolerant coliforms. The values of water samples for pH (6.8-7.6), free and total residual chlorine (0.1-0.5 mg/L), mean lead concentration (0.01 mg/L), and mean arsenic concentration (0.05 mg/L) were within national drinking water quality standards. The presence of domestic animals roaming inside schoolchildren's homes was significantly associated with drinking water contamination (adjusted odds ratio: 1.64; 95% confidence interval: 1.08-2.50; p = 0.02). Our findings call for an improvement of WASH conditions at the unit of school, households, and communities.

Heavy metals in agricultural landscapes as hazards to human and ecosystem health: a case study on zinc and cadmium in drainage channel sediments.

PubMed

Savic, Radovan; Ondrasek, Gabrijel; Josimov-Dundjerski, Jasmina

2015-02-01

In agricultural systems, heavy metals pose severe risks to the health of soil-plant-animal-human continuum. Drainage channels, as integral components of agricultural landscapes, contain sediment material that can be both a source and a sink of metals and other toxic/persistent elements due to its highly reactive interfaces and strong binding affinity. The drainage channel network in a case study area of Vojvodina (Serbia) is not appropriately protected from contamination, nor is it maintained regularly (e.g. by desilting), thus endangering and potentially decreasing the ecological value of surrounding water and agricultural land resources, i.e. exposing food production to potential contaminants. In this study (2004-2012), Cd and Zn concentrations were analysed in 100 samples from 46 drainage channels sediments spread along the areas of the most intensive agricultural land use in Vojvodina. Among the samples measured, 5% had Cd and 14% had Zn concentrations above the maximally permitted levels, indicating that some drainage channel sections have been exposed to different point and non-point source pollutants. The maximum detected concentrations of the analysed elements were >50% (Zn) and were as much as 11-fold (Cd) higher than their remediation values. There is a strong need for the establishment of qualitative monitoring of channel sediment media in agro-ecosystems closely linked with complex pollution sources (intensive agriculture, industry, urban zones). © 2013 Society of Chemical Industry.

Water Quality, Sanitation, and Hygiene Conditions in Schools and Households in Dolakha and Ramechhap Districts, Nepal: Results from A Cross-Sectional Survey

PubMed Central

Shrestha, Akina; Sharma, Subodh; Gerold, Jana; Erismann, Séverine; Sagar, Sanjay; Koju, Rajendra; Schindler, Christian; Odermatt, Peter; Utzinger, Jürg; Cissé, Guéladio

2017-01-01

This study assessed drinking water quality, sanitation, and hygiene (WASH) conditions among 708 schoolchildren and 562 households in Dolakha and Ramechhap districts of Nepal. Cross-sectional surveys were carried out in March and June 2015. A Delagua water quality testing kit was employed on 634 water samples obtained from 16 purposively selected schools, 40 community water sources, and 562 households to examine water quality. A flame atomic absorption spectrophotometer was used to test lead and arsenic content of the same samples. Additionally, a questionnaire survey was conducted to obtain WASH predictors. A total of 75% of school drinking water source samples and 76.9% point-of-use samples (water bottles) at schools, 39.5% water source samples in the community, and 27.4% point-of-use samples at household levels were contaminated with thermo-tolerant coliforms. The values of water samples for pH (6.8–7.6), free and total residual chlorine (0.1–0.5 mg/L), mean lead concentration (0.01 mg/L), and mean arsenic concentration (0.05 mg/L) were within national drinking water quality standards. The presence of domestic animals roaming inside schoolchildren’s homes was significantly associated with drinking water contamination (adjusted odds ratio: 1.64; 95% confidence interval: 1.08–2.50; p = 0.02). Our findings call for an improvement of WASH conditions at the unit of school, households, and communities. PMID:28106779

Ambulance vehicles as a source of multidrug-resistant infections: a multicenter study in Assiut City, Egypt

PubMed Central

2018-01-01

Background Ambulances may represent a potential source of infection to patients, patients’ relatives, and paramedical staffs. In this study, we analyzed the extent of bacterial contamination in ambulance vehicles and measured the degree of antimicrobial resistance among isolated pathogens. Materials and methods Twenty-five vehicles were included and 16 sampling points were swabbed in each vehicle. Then the swabs were immediately transferred to the laboratory to identify bacterial contaminants utilizing standard microbiological procedures and API® systems. Antibiotic susceptibility testing and screening for methicillin-resistant staphylococci and extended spectrum β-lactamases (ESBLs)-producing Gram-negative rods were carried out. Results A total of 400 samples were collected, 589 bacteria were isolated and 286 (48.6%) of the isolates were potentially pathogenic. The highest contamination rate with pathogenic bacteria was detected in suction devices (75.8%) and stethoscopes (67.7%). Staphylococci were the most frequently detected microorganisms (n=184) followed by Klebsiella spp. (49), Escherichia coli (40), Citrobacter spp. (7), and Proteus spp. (6). Staphylococci were mostly sensitive to vancomycin, whereas Gram-negative bacteria were sensitive to imipenem. Overall, 46.1% of Staphylococcus aureus were methicillin resistant, whereas 20.4% of the coagulase-negative staphylococci were methicillin resistant. Moreover, 36.7% of Klebsiella spp. and 27.5% of E. coli were ESBL producers. Conclusion Our study provides evidence that ambulances represent a source of prehospital multidrug-resistant infections. PMID:29731647

Distributions and fate of chlorinated pesticides, biomarkers and polycyclic aromatic hydrocarbons in sediments along a contamination gradient from a point-source in San Francisco Bay, California

USGS Publications Warehouse

Pereira, W.E.; Hostettler, F.D.; Rapp, J.B.

1996-01-01

The distribution and fate of chlorinated pesticides, biomarkers, and polycyclic aromatic hydrocarbons (PAHs) in surficial sediments along a contamination gradient in the Lauritzen Canal and Richmond Harbor in San Francisco Bay was investigated. Compounds were identified and quantified using gas chromatography-ion trap mass spectrometry. Biomarkers and PAHs were derived primarily from weathered petroleum. DDT was reductively dechlorinated under anoxic conditions to DDD and several minor degradation products, DDMU, DDMS, and DDNU. Under aerobic conditions, DDT was dehydrochlorinated to DDE and DBP. Aerobic degradation of DDT was diminished or inhibited in zones of high concentration, and increased significantly in zones of lower concentration: Other chlorinated pesticides identified in sediment included dieldrin and chlordane isomers. Multivariate analysis of the distributions of the DDTs suggested that there are probably two sources of DDD. In addition, DDE and DDMU are probably formed by similar mechanisms, i.e. dehydrochlorination. A steep concentration gradient existed from the Canal to the Outer Richmond Harbor, but higher levels of DDD than those found in the remainder of the Bay indicated that these contaminants are transported on particulates and colloidal organic matter from this source into San Francisco Bay. Chlorinated pesticides and PAHs may pose a potential problem to biota in San Francisco Bay.

Potential Effectiveness of Point-of-Use Filtration to Address Risks to Drinking Water in the United States

PubMed Central

Brown, Kathleen Ward; Gessesse, Bemnet; Butler, Lindsey J; MacIntosh, David L

2017-01-01

Numerous contemporary incidents demonstrate that conventional control strategies for municipal tap water have limited ability to mitigate exposures to chemicals whose sources are within distribution systems, such as lead, and chemicals that are not removed by standard treatment technologies, such as perfluorooctanoic acid (PFOA)/perfluorooctanesulfonic acid (PFOS). In these situations, point-of-use (POU) controls may be effective in mitigating exposures and managing health risks of chemicals in drinking water, but their potential utility has not been extensively examined. As an initial effort to fill this information gap, we conducted a critical review and analysis of the existing literature and data on the effectiveness of POU drinking water treatment technologies for reducing chemical contaminants commonly found in tap water in the United States. We found that many types of water treatment devices available to consumers in the United States have undergone laboratory testing and often certification for removal of chemical contaminants in tap water, but in most cases their efficacy in actual use has yet to be well characterized. In addition, the few studies of POU devices while “in use” focus on traditional contaminants regulated under the Safe Drinking Water Act, but do not generally consider nontraditional contaminants of concern, such as certain novel human carcinogens, industrial chemicals, pesticides, pharmaceuticals, personal care products, and flame retardants. Nevertheless, the limited information available at present suggests that POU devices can be highly effective when used prophylactically and when deployed in response to contamination incidents. Based on these findings, we identify future areas of research for assessing the ability of POU filters to reduce health-related chemical contaminants distributed through public water systems and private wells. PMID:29270018

Critical control points for avian influenza A H5N1 in live bird markets in low resource settings.

PubMed

Samaan, Gina; Gultom, Anita; Indriani, Risa; Lokuge, Kamalini; Kelly, Paul M

2011-06-01

Live bird markets can become contaminated with and become a source of transmission for avian influenza viruses including the highly pathogenic H5N1 strain. Many countries affected by the H5N1-virus have limited resources for programs in environmental health, sanitation and disease control in live bird markets. This study proposes five critical control points (CCPs) to reduce the risk of H5N1-virus contamination in markets in low resource settings. The CCPs were developed based on three surveys conducted in Indonesia: a cross-sectional survey in 119 markets, a knowledge, attitudes and practice survey in 3 markets and a microbiological survey in 83 markets. These surveys assessed poultry workflow, market infrastructure, hygiene and regulatory practices and microbiological contamination with the H5N1-virus. The five CCPs identified were (1) reducing risk of receiving infected birds into the market, (2) reducing the risk of virus spread between different bird flocks in holding cages, (3) reducing surface contamination by isolating slaughter processes from other poultry-related processes, (4) minimizing the potential for contamination during evisceration of carcasses and (5) reducing the risk of surface contamination in the sale zone of the market. To be relevant for low resource settings, the CCPs do not necessitate large infrastructure changes. The CCPs are suited for markets that slaughter poultry and have capacity for daily disposal and removal of solid waste from the market. However, it is envisaged that the CCPs can be adapted for the development of risk-based programs in various settings. Copyright © 2011 Elsevier B.V. All rights reserved.

Legionella in industrial cooling towers: monitoring and control strategies.

PubMed

Carducci, A; Verani, M; Battistini, R

2010-01-01

Legionella contamination of industrial cooling towers has been identified as the cause of sporadic cases and outbreaks of legionellosis among people living nearby. To evaluate and control Legionella contamination in industrial cooling tower water, microbiological monitoring was carried out to determine the effectiveness of the following different disinfection treatments: (i) continuous chlorine concentration of 0.01 ppm and monthly chlorine shock dosing (5 ppm) on a single cooling tower; (ii) continuous chlorine concentration of 0.4 ppm and monthly shock of biocide P3 FERROCID 8580 (BKG Water Solution) on seven towers. Legionella spp. and total bacterial count (TBC) were determined 3 days before and after each shock dose. Both strategies demonstrated that when chlorine was maintained at low levels, the Legionella count grew to levels above 10(4) CFU l(-1) while TBC still remained above 10(8 )CFU l(-1). Chlorine shock dosing was able to eliminate bacterial contamination, but only for 10-15 days. Biocide shock dosing was also insufficient to control the problem when the disinfectant concentration was administered at only one point in the plant and at the concentration of 30 ppm. On the other hand, when at a biocide concentration of 30 or 50 ppm was distributed throughout a number of points, depending on the plant hydrodynamics, Legionella counts decreased significantly and often remained below the warning limit. Moreover, the contamination of water entering the plant and the presence of sediment were also important factors for Legionella growth. For effective decontamination of outdoor industrial cooling towers, disinfectants should be distributed in a targeted way, taking into account the possible sources of contamination. The data of the research permitted to modify the procedure of disinfection for better reduce the water and aerosol contamination and consequently the exposure risk.

Potential Effectiveness of Point-of-Use Filtration to Address Risks to Drinking Water in the United States.

PubMed

Brown, Kathleen Ward; Gessesse, Bemnet; Butler, Lindsey J; MacIntosh, David L

2017-01-01

Numerous contemporary incidents demonstrate that conventional control strategies for municipal tap water have limited ability to mitigate exposures to chemicals whose sources are within distribution systems, such as lead, and chemicals that are not removed by standard treatment technologies, such as perfluorooctanoic acid (PFOA)/perfluorooctanesulfonic acid (PFOS). In these situations, point-of-use (POU) controls may be effective in mitigating exposures and managing health risks of chemicals in drinking water, but their potential utility has not been extensively examined. As an initial effort to fill this information gap, we conducted a critical review and analysis of the existing literature and data on the effectiveness of POU drinking water treatment technologies for reducing chemical contaminants commonly found in tap water in the United States. We found that many types of water treatment devices available to consumers in the United States have undergone laboratory testing and often certification for removal of chemical contaminants in tap water, but in most cases their efficacy in actual use has yet to be well characterized. In addition, the few studies of POU devices while "in use" focus on traditional contaminants regulated under the Safe Drinking Water Act, but do not generally consider nontraditional contaminants of concern, such as certain novel human carcinogens, industrial chemicals, pesticides, pharmaceuticals, personal care products, and flame retardants. Nevertheless, the limited information available at present suggests that POU devices can be highly effective when used prophylactically and when deployed in response to contamination incidents. Based on these findings, we identify future areas of research for assessing the ability of POU filters to reduce health-related chemical contaminants distributed through public water systems and private wells.

Biological Processes Affecting Bioaccumulation, Transfer, and Toxicity of Metal Contaminants in Estuarine Sediments

DTIC Science & Technology

2011-12-01

ER-1503 December 2011 Celia Y. Chen Dartmouth College Nicholas S. Fisher Stonybrook University Joseph R. Shaw Indiana University...and Cd because of their importance in DoD sites and other industrial point sources. Hg comes from the combustion of fossil fuels, cadmium from...investigate the trophic transfer of cadmium , inorganic mercury and methylmercury from phytoplankton to a benthic amphipod to fish, simulating a

The metallic contamination of the Loire River Basin (France): Spatial and temporal evolution with a multi-scale approach

NASA Astrophysics Data System (ADS)

Dhivert, Elie; Grosbois, Cécile; Desmet, Marc; Curie, Florence; Moatar, Florentina; Meybeck, Michel; Bourrain, Xavier

2013-04-01

Since the early 19th century, important agricultural, mining and industrial development has been active in Western Europe. The Loire River Basin (117,800 km2, total population of 8.4 Mp) presents a long history of human pressures, reflecting temporal evolution of technological and urban activities (Grosbois et al, 2012). Hence, sediments of the Loire River and its tributaries have recorded partially and/or totally organic, nutrients and trace element contamination. Nowadays, can we determine history of metallic emissions in sediment records and what is the part of these past inputs relative to the actual contamination? Can we point out historical sources of contamination? To answer these questions, two approaches were used in this study. Firstly, in four coring sites in the Loire River Basin, a temporal re-enacting of metallic contamination trapped in sediments was carried out. Based on age-model and inter-element correlations in each core, trace element signals were deconvoluted and compared to actual and specific chemical signatures of anthropogenic inputs (300 bed sediment samples collected downstream of former and current industrial sites like mines, smelters, planting/coating plants, glassware and car industries, metal recycling plants and waste water treatment plants). The second approach was at a larger basin scale, comparing location of these former and actual contamination sources with explanatory factors such as geology, evolution of population density, of industrial activities and of land use. This was done in the main stream of the Loire River and its major tributaries and locally at a smaller scale (0-500 km²). All these approaches emphasized three temporal periods of metallic contamination: (i) the first period begins with the 20th century until 1950, it corresponds to the first increase of major contaminants like Ag, As, Cd, Cr, Hg, Pb, Sb, Sn and Zn; some trace elements like Hg and Sn seem to be present in the Loire sediments much earlier as they were already enriched before 1900.; (ii) the second one (1950-1980s) represents the highest level of contamination for the cited contaminants above; (iii) the last period is characterized by a large decrease of pollution from 1980s to nowadays when environmental policies and contaminant emission control started. At a spatial scale, small and medium-scale sub-basins, presenting numerous important mining sites and associated industrial plants, are specifically associated to local sources. In contrast, industrial and urban poles are related to polymetallic concentrated bed sediments.

An assessment of air as a source of DNA contamination encountered when performing PCR.

PubMed

Witt, Nina; Rodger, Gillian; Vandesompele, Jo; Benes, Vladimir; Zumla, Alimuddin; Rook, Graham A; Huggett, Jim F

2009-12-01

Sensitive molecular methods, such as the PCR, can detect low-level contamination, and careful technique is required to reduce the impact of contaminants. Yet, some assays that are designed to detect high copy-number target sequences appear to be impossible to perform without contamination, and frequently, personnel or laboratory environment are held responsible as the source. This complicates diagnostic and research analysis when using molecular methods. To investigate the air specifically as a source of contamination, which might occur during PCR setup, we exposed tubes of water to the air of a laboratory and clean hood for up to 24 h. To increase the chances of contamination, we also investigated a busy open-plan office in the same way. All of the experiments showed the presence of human and rodent DNA contamination. However, there was no accumulation of the contamination in any of the environments investigated, suggesting that the air was not the source of contamination. Even the air from a busy open-plan office was a poor source of contamination for all of the DNA sequences investigated (human, bacterial, fungal, and rodent). This demonstrates that the personnel and immediate laboratory environment are not necessarily to blame for the observed contamination.

Strategies for lidar characterization of particulates from point and area sources

NASA Astrophysics Data System (ADS)

Wojcik, Michael D.; Moore, Kori D.; Martin, Randal S.; Hatfield, Jerry

2010-10-01

Use of ground based remote sensing technologies such as scanning lidar systems (light detection and ranging) has gained traction in characterizing ambient aerosols due to some key advantages such as wide area of regard (10 km2), fast response time, high spatial resolution (<10 m) and high sensitivity. Energy Dynamics Laboratory and Utah State University, in conjunction with the USDA-ARS, has developed a three-wavelength scanning lidar system called Aglite that has been successfully deployed to characterize particle motion, concentration, and size distribution at both point and diffuse area sources in agricultural and industrial settings. A suite of massbased and size distribution point sensors are used to locally calibrate the lidar. Generating meaningful particle size distribution, mass concentration, and emission rate results based on lidar data is dependent on strategic onsite deployment of these point sensors with successful local meteorological measurements. Deployment strategies learned from field use of this entire measurement system over five years include the characterization of local meteorology and its predictability prior to deployment, the placement of point sensors to prevent contamination and overloading, the positioning of the lidar and beam plane to avoid hard target interferences, and the usefulness of photographic and written observational data.

Differentiation of fecal Escherichia coli from poultry and free-living birds by (GTG)5-PCR genomic fingerprinting.

PubMed

Mohapatra, Bidyut R; Broersma, Klaas; Mazumder, Asit

2008-04-01

Determination of the non-point sources of fecal pollution is essential for the assessment of potential public health risk and development of appropriate management practices for prevention of further contamination. Repetitive extragenic palindromic-PCR coupled with (GTG)(5) primer [(GTG)(5)-PCR] was performed on 573 Escherichia coli isolates obtained from the feces of poultry (chicken, duck and turkey) and free-living (Canada goose, hawk, magpie, seagull and songbird) birds to evaluate the efficacy of (GTG)(5)-PCR genomic fingerprinting in the prediction of the correct source of fecal pollution. A discriminant analysis with the jack-knife algorithm of (GTG)(5)-PCR DNA fingerprints revealed that 95%, 94.1%, 93.2%, 84.6%, 79.7%, 76.7%, 75.3% and 70.7% of magpie, hawk, turkey, seagull, Canada goose, chicken, duck and songbird fecal E. coli isolates classified into the correct host source, respectively. The results of this study indicate that (GTG)(5)-PCR can be considered to be a complementary molecular tool for the rapid determination of E. coli isolates identity and tracking the non-point sources of fecal pollution.

Potential effects of groundwater and surface water contamination in an urban area, Qus City, Upper Egypt

NASA Astrophysics Data System (ADS)

Abdalla, Fathy; Khalil, Ramadan

2018-05-01

The potential effects of anthropogenic activities, in particular, unsafe sewage disposal practices, on shallow groundwater in an unconfined aquifer and on surface water were evaluated within an urban area by the use of hydrogeological, hydrochemical, and bacteriological analyses. Physicochemical and bacteriological data was obtained from forty-five sampling points based on33 groundwater samples from variable depths and 12 surface water samples. The pollution sources are related to raw sewage and wastewater discharges, agricultural runoff, and wastewater from the nearby Paper Factory. Out of the 33 groundwater samples studied, 17 had significant concentrations of NO3-, Cl- and SO42-, and high bacteria counts. Most of the water samples from the wells contained high Fe, Mn, Pb, Zn, Cd, and Cr. The majority of surface water samples presented high NO3- concentrations and high bacteria counts. A scatter plot of HCO3- versus Ca indicates that 58% of the surface water samples fall within the extreme contamination zone, while the others are within the mixing zone; whereas 94% of groundwater samples showed evidence of mixing between groundwater and wastewater. The bacteriological assessment showed that all measured surface and groundwater samples contained Escherichia coli and total coliform bacteria. A risk map delineated four classes of contamination, namely, those sampling points with high (39.3%), moderate (36.3%), low (13.3%), and very low (11.1%) levels of contamination. Most of the highest pollution points were in the middle part of the urban area, which suffers from unmanaged sewage and industrial effluents. Overall, the results demonstrate that surface and groundwater in Qus City are at high risk of contamination by wastewater since the water table is shallow and there is a lack of a formal sanitation network infrastructure. The product risk map is a useful tool for prioritizing zones that require immediate mitigation and monitoring.

Natural Remediation at Savannah River Site

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lewis, C. M.; Van Pelt, R.

2002-02-25

Natural remediation is a general term that includes any technology or strategy that takes advantage of natural processes to remediate a contaminated media to a condition that is protective of human health and the environment. Natural remediation techniques are often passive and minimally disruptive to the environment. They are generally implemented in conjunction with traditional remedial solutions for source control (i.e., capping, stabilization, removal, soil vapor extraction, etc.). Natural remediation techniques being employed at Savannah River Site (SRS) include enhanced bio-remediation, monitored natural attenuation, and phytoremediation. Enhanced bio-remediation involves making nutrients available and conditions favorable for microbial growth. With propermore » precautions and feeding, the naturally existing microbes flourish and consume the contaminants. Case studies of enhanced bio-remediation include surface soils contaminated with PCBs and pesticides, and Volatile Organic Compound (VOC) contamination in both the vadose zone and groundwater. Monitored natural attenuation (MNA) has been selected as the preferred alternative for groundwater clean up at several SRS waste units. Successful implementation of MNA has been based on demonstration that sources have been controlled, groundwater modeling that indicates that plumes will not expand or reach surface water discharge points at levels that exceed regulatory limits, and continued monitoring. Phytoremediation is being successfully utilized at several SRS waste units. Phytoremediation involves using plants and vegetation to uptake, break down, or manage contaminants in groundwater or soils. Case studies at SRS include managing groundwater plumes of tritium and VOCs with pine trees that are native to the area. Significant decreases in tritium discharge to a site stream have been realized in one phytoremediation project. Studies of other vegetation types, methods of application, and other target contaminants are underway.« less

Screening tool to evaluate the vulnerability of down-gradient receptors to groundwater contaminants from uncapped landfills

USGS Publications Warehouse

Baker, Ronald J.; Reilly, Timothy J.; Lopez, Anthony R.; Romanok, Kristin M.; Wengrowski, Edward W

2015-01-01

A screening tool for quantifying levels of concern for contaminants detected in monitoring wells on or near landfills to down-gradient receptors (streams, wetlands and residential lots) was developed and evaluated. The tool uses Quick Domenico Multi-scenario (QDM), a spreadsheet implementation of Domenico-based solute transport, to estimate concentrations of contaminants reaching receptors under steady-state conditions from a constant-strength source. Unlike most other available Domenico-based model applications, QDM calculates the time for down-gradient contaminant concentrations to approach steady state and appropriate dispersivity values, and allows for up to fifty simulations on a single spreadsheet. Sensitivity of QDM solutions to critical model parameters was quantified. The screening tool uses QDM results to categorize landfills as having high, moderate and low levels of concern, based on contaminant concentrations reaching receptors relative to regulatory concentrations. The application of this tool was demonstrated by assessing levels of concern (as defined by the New Jersey Pinelands Commission) for thirty closed, uncapped landfills in the New Jersey Pinelands National Reserve, using historic water-quality data from monitoring wells on and near landfills and hydraulic parameters from regional flow models. Twelve of these landfills are categorized as having high levels of concern, indicating a need for further assessment. This tool is not a replacement for conventional numerically-based transport model or other available Domenico-based applications, but is suitable for quickly assessing the level of concern posed by a landfill or other contaminant point source before expensive and lengthy monitoring or remediation measures are taken. In addition to quantifying the level of concern using historic groundwater-monitoring data, the tool allows for archiving model scenarios and adding refinements as new data become available.

Contamination control engineering design guidelines for the aerospace community

NASA Technical Reports Server (NTRS)

Tribble, A. C. (Principal Investigator); Boyadjian, B.; Davis, J.; Haffner, J.; McCullough, E.

1996-01-01

Thermal control surfaces, solar arrays, and optical devices may be adversely affected by a small quantity of molecular and/or particulate contamination. What is rarely discussed is how one: (1) quantifies the level of contamination that must be maintained in order for the system to function properly, and (2) enforces contamination control to ensure compliance with requirements. This document is designed to address these specific issues and is intended to serve as a handbook on contamination control for the reader, illustrating process and methodology while providing direction to more detailed references when needed. The effects of molecular contamination on reflecting and transmitting surfaces are examined and quantified in accordance with MIL STD 1246C. The generation, transportation, and deposition of molecular contamination is reviewed and specific examples are worked to illustrate the process a design engineer can use to estimate end of life cleanliness levels required by solar arrays, thermal control surfaces, and optical surfaces. A similar process is used to describe the effect of particulate contamination as related to percent area coverage (PAC) and bi-directional reflectance distribution function (BRDF). Relationships between PAC and surface cleanliness, which include the effects of submicron sized particles, are developed and BRDF is related to specific sensor design parameters such as Point Source Transmittance (PST). The pros and cons of various methods of preventing, monitoring, and cleaning surfaces are examined and discussed.

Point-of-Use Interventions to Decrease Contamination of Drinking Water: A Randomized, Controlled Pilot Study on Efficacy, Effectiveness, and Acceptability of Closed Containers, Moringa oleifera, and In-home Chlorination in Rural South India

PubMed Central

Firth, Jacqueline; Balraj, Vinohar; Muliyil, Jayaprakash; Roy, Sheela; Rani, Lilly Michael; Chandresekhar, R.; Kang, Gagandeep

2010-01-01

To assess water contamination and the relative effectiveness of three options for point-of-use water treatment in South India, we conducted a 6-month randomized, controlled intervention trial using chlorine, Moringa oleifera seeds, a closed valved container, and controls. One hundred twenty-six families participated. Approximately 70% of public drinking water sources had thermotolerant coliform counts > 100/100 mL. Neither M. oleifera seeds nor containers reduced coliform counts in water samples from participants' homes. Chlorine reduced thermotolerant coliform counts to potable levels, but was less acceptable to participants. Laboratory testing of M. oleifera seeds in water from the village confirmed the lack of reduction in coliform counts, in contrast to the improvement seen with Escherichia coli seeded distilled water. This discrepancy merits further study, as M. oleifera was effective in reducing coliform counts in other studies and compliance with Moringa use in this study was high. PMID:20439952

Outbreaks attributed to fresh leafy vegetables, United States, 1973–2012

PubMed Central

HERMAN, K. M.; HALL, A. J.; GOULD, L. H.

2015-01-01

SUMMARY Leafy vegetables are an essential component of a healthy diet; however, they have been associated with high-profile outbreaks causing severe illnesses. We reviewed leafy vegetable-associated outbreaks reported to the Centers for Disease Control and Prevention between 1973 and 2012. During the study period, 606 leafy vegetable-associated outbreaks, with 20 003 associated illnesses, 1030 hospitalizations, and 19 deaths were reported. On average, leafy vegetable-associated outbreaks were larger than those attributed to other food types. The pathogens that most often caused leafy vegetable-associated outbreaks were norovirus (55% of outbreaks with confirmed aetiology), Shiga toxin-producing Escherichia coli (STEC) (18%), and Salmonella (11%). Most outbreaks were attributed to food prepared in a restaurant or catering facility (85%). An ill food worker was implicated as the source of contamination in 31% of outbreaks. Efforts by local, state, and federal agencies to control leafy vegetable contamination and outbreaks should span from the point of harvest to the point of preparation. PMID:25697407

Point-of-use interventions to decrease contamination of drinking water: a randomized, controlled pilot study on efficacy, effectiveness, and acceptability of closed containers, Moringa oleifera, and in-home chlorination in rural South India.

PubMed

Firth, Jacqueline; Balraj, Vinohar; Muliyil, Jayaprakash; Roy, Sheela; Rani, Lilly Michael; Chandresekhar, R; Kang, Gagandeep

2010-05-01

To assess water contamination and the relative effectiveness of three options for point-of-use water treatment in South India, we conducted a 6-month randomized, controlled intervention trial using chlorine, Moringa oleifera seeds, a closed valved container, and controls. One hundred twenty-six families participated. Approximately 70% of public drinking water sources had thermotolerant coliform counts > 100/100 mL. Neither M. oleifera seeds nor containers reduced coliform counts in water samples from participants' homes. Chlorine reduced thermotolerant coliform counts to potable levels, but was less acceptable to participants. Laboratory testing of M. oleifera seeds in water from the village confirmed the lack of reduction in coliform counts, in contrast to the improvement seen with Escherichia coli seeded distilled water. This discrepancy merits further study, as M. oleifera was effective in reducing coliform counts in other studies and compliance with Moringa use in this study was high.

Outbreaks attributed to fresh leafy vegetables, United States, 1973-2012.

PubMed

Herman, K M; Hall, A J; Gould, L H

2015-10-01

Leafy vegetables are an essential component of a healthy diet; however, they have been associated with high-profile outbreaks causing severe illnesses. We reviewed leafy vegetable-associated outbreaks reported to the Centers for Disease Control and Prevention between 1973 and 2012. During the study period, 606 leafy vegetable-associated outbreaks, with 20 003 associated illnesses, 1030 hospitalizations, and 19 deaths were reported. On average, leafy vegetable-associated outbreaks were larger than those attributed to other food types. The pathogens that most often caused leafy vegetable-associated outbreaks were norovirus (55% of outbreaks with confirmed aetiology), Shiga toxin-producing Escherichia coli (STEC) (18%), and Salmonella (11%). Most outbreaks were attributed to food prepared in a restaurant or catering facility (85%). An ill food worker was implicated as the source of contamination in 31% of outbreaks. Efforts by local, state, and federal agencies to control leafy vegetable contamination and outbreaks should span from the point of harvest to the point of preparation.

Semi-quantitative evaluation of fecal contamination potential by human and ruminant sources using multiple lines of evidence

USGS Publications Warehouse

Stoeckel, D.M.; Stelzer, E.A.; Stogner, R.W.; Mau, D.P.

2011-01-01

Protocols for microbial source tracking of fecal contamination generally are able to identify when a source of contamination is present, but thus far have been unable to evaluate what portion of fecal-indicator bacteria (FIB) came from various sources. A mathematical approach to estimate relative amounts of FIB, such as Escherichia coli, from various sources based on the concentration and distribution of microbial source tracking markers in feces was developed. The approach was tested using dilute fecal suspensions, then applied as part of an analytical suite to a contaminated headwater stream in the Rocky Mountains (Upper Fountain Creek, Colorado). In one single-source fecal suspension, a source that was not present could not be excluded because of incomplete marker specificity; however, human and ruminant sources were detected whenever they were present. In the mixed-feces suspension (pet and human), the minority contributor (human) was detected at a concentration low enough to preclude human contamination as the dominant source of E. coli to the sample. Without the semi-quantitative approach described, simple detects of human-associated marker in stream samples would have provided inaccurate evidence that human contamination was a major source of E. coli to the stream. In samples from Upper Fountain Creek the pattern of E. coli, general and host-associated microbial source tracking markers, nutrients, and wastewater-associated chemical detections-augmented with local observations and land-use patterns-indicated that, contrary to expectations, birds rather than humans or ruminants were the predominant source of fecal contamination to Upper Fountain Creek. This new approach to E. coli allocation, validated by a controlled study and tested by application in a relatively simple setting, represents a widely applicable step forward in the field of microbial source tracking of fecal contamination. ?? 2011 Elsevier Ltd.

Relationship between mass-flux reduction and source-zone mass removal: analysis of field data.

PubMed

Difilippo, Erica L; Brusseau, Mark L

2008-05-26

The magnitude of contaminant mass-flux reduction associated with a specific amount of contaminant mass removed is a key consideration for evaluating the effectiveness of a source-zone remediation effort. Thus, there is great interest in characterizing, estimating, and predicting relationships between mass-flux reduction and mass removal. Published data collected for several field studies were examined to evaluate relationships between mass-flux reduction and source-zone mass removal. The studies analyzed herein represent a variety of source-zone architectures, immiscible-liquid compositions, and implemented remediation technologies. There are two general approaches to characterizing the mass-flux-reduction/mass-removal relationship, end-point analysis and time-continuous analysis. End-point analysis, based on comparing masses and mass fluxes measured before and after a source-zone remediation effort, was conducted for 21 remediation projects. Mass removals were greater than 60% for all but three of the studies. Mass-flux reductions ranging from slightly less than to slightly greater than one-to-one were observed for the majority of the sites. However, these single-snapshot characterizations are limited in that the antecedent behavior is indeterminate. Time-continuous analysis, based on continuous monitoring of mass removal and mass flux, was performed for two sites, both for which data were obtained under water-flushing conditions. The reductions in mass flux were significantly different for the two sites (90% vs. approximately 8%) for similar mass removals ( approximately 40%). These results illustrate the dependence of the mass-flux-reduction/mass-removal relationship on source-zone architecture and associated mass-transfer processes. Minimal mass-flux reduction was observed for a system wherein mass removal was relatively efficient (ideal mass-transfer and displacement). Conversely, a significant degree of mass-flux reduction was observed for a site wherein mass removal was inefficient (non-ideal mass-transfer and displacement). The mass-flux-reduction/mass-removal relationship for the latter site exhibited a multi-step behavior, which cannot be predicted using some of the available simple estimation functions.

Probabilistic analysis showing that a combination of bacteroides and methanobrevibacter source tracking markers is effective for identifying waters contaminated by human fecal pollution

USGS Publications Warehouse

Johnston, Christopher; Byappanahalli, Muruleedhara N.; Gibson, Jacqueline MacDonald; Ufnar, Jennifer A.; Whitman, Richard L.; Stewart, Jill R.

2013-01-01

Microbial source tracking assays to identify sources of waterborne contamination typically target genetic markers of host-specific microorganisms. However, no bacterial marker has been shown to be 100% host-specific, and cross-reactivity has been noted in studies evaluating known source samples. Using 485 challenge samples from 20 different human and animal fecal sources, this study evaluated microbial source tracking markers including the Bacteroides HF183 16S rRNA, M. smithii nifH, and Enterococcus esp gene targets that have been proposed as potential indicators of human fecal contamination. Bayes' Theorem was used to calculate the conditional probability that these markers or a combination of markers can correctly identify human sources of fecal pollution. All three human-associated markers were detected in 100% of the sewage samples analyzed. Bacteroides HF183 was the most effective marker for determining whether contamination was specifically from a human source, and greater than 98% certainty that contamination was from a human source was shown when both Bacteroides HF183 and M. smithii nifH markers were present. A high degree of certainty was attained even in cases where the prior probability of human fecal contamination was as low as 8.5%. The combination of Bacteroides HF183 and M. smithii nifH source tracking markers can help identify surface waters impacted by human fecal contamination, information useful for prioritizing restoration activities or assessing health risks from exposure to contaminated waters.

Three studies using Ceriodaphnia to detect nonpoint sources of metals from mine drainage

USGS Publications Warehouse

Nimmo, Del Wayne R.; Dodson, Max H.; Davies, Patrick H.; Greene, Joseph C.; Kerr, Mark A.

1990-01-01

Since its introduction, Ceriodaphnia dubia, a small planktonic daphnid, has been widely used for biomonitoring point source discharges. This species was also used to determine nonpoint sources of metals and related contaminants in three trout streams in the west where mining activities have been widespread. Along Chalk Creek, Colo., specific tailings (and impacted tributaries) were sources of metals toxic to fish using the water in a hatchery. At stations below extensive mine tailings in the upper Clark Fork River, Mont., drainage was acutely and chronically toxic to daphnids and paralleled reduced or nonexistent populations of trout. In Whitewood Creek, S. Dak., reduced toxicity below a gold mine portended that fish could live in the stream segment previously impaired by the mine. Toxicity downstream revealed a previously unknown nonpoint source of chromium.

Contamination characteristics and source apportionment of heavy metals in topsoil from an area in Xi'an city, China.

PubMed

Chen, Xiuduan; Lu, Xinwei

2018-04-30

As soil-extractable elements potentially pose ecological and health risks, identifying their contamination characteristics and sources is crucial. Therefore, to understand topsoil trace elements in the urban ring zone from the Second Ring Road to the Third Ring of Xi'an city in China, we determined the concentrations of Zn, Co, V, As, Cu, Mn, Ba, Ni and Pb, and analyzed the sources of the contamination. The results showed that the individual pollution indices of Pb, Co, Cu, Zn, Ba, Ni, Mn, As, and V were 1.79, 1.48, 1.41, 1.33, 1.20, 1.07, 1.04, 0.99, and 0.99, respectively. Evaluation with the aid of the pollution load index (PLI) indicated slight soil contamination by these elements in the study area. Using the positive matrix factorization (PMF) method, we identified four sources of contamination, namely (1) a natural source, (2) traffic emission source, (3) industrial emission source, and (4) mixed source. PMF is an effective tool for source apportionment of heavy metals in topsoil. The contribution rates of the natural source, traffic source, mixed source, and industrial source to the heavy metal contamination were specified as 25.04%, 24.71%, 24.99%, and 25.26%, respectively. Considering the above, any attempt to reduce the soil environmental cost of urban development, has to take into account the heavy metal contamination of the topsoil from industries, traffic, and other activities. Copyright © 2018 Elsevier Inc. All rights reserved.

Characterization of atmospheric emission sources in lichen from metal and organic contaminant patterns.

PubMed

Ratier, Aude; Dron, Julien; Revenko, Gautier; Austruy, Annabelle; Dauphin, Charles-Enzo; Chaspoul, Florence; Wafo, Emmanuel

2018-03-01

Lichen samples from contrasted environments, influenced by various anthropic activities, were investigated focusing on the contaminant signatures according to the atmospheric exposure typologies. Most of the contaminant concentrations measured in the 27 lichen samples, collected around the industrial harbor of Fos-sur-Mer (France), were moderate in rural and urban environments, and reached extreme levels in industrial areas and neighboring cities (Al up to 6567 mg kg -1 , Fe 42,398 mg kg -1 , or ΣPAH 1417 μg kg -1 for example). At the same time, a strong heterogeneity was noticed in industrial samples while urban and rural ones were relatively homogeneous. Several metals could be associated to steel industry (Fe, Mn, Cd), road traffic, and agriculture (Sb, Cu, Sn), or to a distinct chemical installation (Mo). As well, PCDFs dominated in industrial samples while PCDDs prevailed in urban areas. The particularities observed supported the purpose of this work and discriminated the contributions of various atmospheric pollution emission sources in lichen samples. A statistical approach based on principal component analysis (PCA) was applied and resolved these potential singularities into specific component factors. Even if a certain degree of mixing of the factors is pointed out, relevant relationships were observed with several atmospheric emission sources. By this methodology, the contribution of industrial emissions to the atmospheric metal, PAH, PCB, and PCDD/F levels was roughly estimated to be 60.2%, before biomass burning (10.2%) and road traffic (3.8%). These results demonstrate that lichen biomonitoring offers an encouraging perspective of spatially resolved source apportionment studies.

Bacterial indicator occurrence and the use of an F+ specific RNA coliphage assay to identify fecal sources in Homosassa Springs, Florida

USGS Publications Warehouse

Griffin, Dale W.; Stokes, Rodger; Rose, J.B.; Paul, J.H.

2000-01-01

A microbiological water quality study of Homosassa Springs State Wildlife Park (HSSWP) and surrounding areas was undertaken. Samples were collected in November of 1997 (seven sites) and again in November of 1998 (nine sites). Fecal bacterial concentrations (total and fecal coliforms, Clostridium perfringens, and enterococci) were measured as relative indicators of fecal contamination. F+-specific coliphage genotyping was performed to determine the source of fecal contamination at the study sites. Bacterial levels were considerably higher at most sites in the 1997 sampling compared to the 1998 sampling, probably because of the greater rainfall that year. In November of 1997, 2 of the 7 sites were in violation of all indicator standards and guidance levels. In November of 1998, 1 of 9 sites was in violation of all indicator standard and guidance levels. The highest concentrations of all fecal indicators were found at a station downstream of the animal holding pens in HSSWP. The lowest levels of indicators were found at the Homosassa Main Spring vent. Levels of fecal indicators downstream of HSSWP (near the point of confluence with the river) were equivalent to those found in the Southeastern Fork and areas upstream of the park influences. F+ specific RNA coliphage analysis indicated that fecal contamination at all sites that tested positive was from animal sources (mammals and birds). These results suggest that animal (indigenous and those in HSSWP) and not human sources influenced microbial water quality in the area of Homosassa River covered by this study.

Groundwater pollution and remediation options for multi-source contaminated aquifers (Bitterfeld/Wolfen, Germany).

PubMed

Wycisk, P; Weiss, H; Kaschl, A; Heidrich, S; Sommerwerk, K

2003-04-11

Large-scale contaminated megasites like Bitterfeld/Wolfen in the eastern part of Germany are characterized by a regional pollution of soil, surface water and groundwater due to the long and varied history of the chemical industry on location. The pollutants in groundwater may spread to uncontaminated areas and endanger receptors like surface water and drinking water wells according to the site-specific hydrologic regime. In addition, the sheer extension of the contamination at megasites as well as the existence of large densely populated areas and land of high-reuse value prevent a simple risk management strategy of use restriction for the whole area. Since a complete clean-up of the groundwater on a megasite is neither economically feasible nor technically possible within a reasonable time-frame, a multi-approach remediation strategy is needed, taking into account the immediate risks for human health, ecosystem and so-called "protectable goods". Moreover, the contaminants at megasites typically represent a dangerous cocktail of multiple harmful substances stemming from a variety of sources, which may interact with each other and complicate the search for an appropriate remediation strategy. At the SAFIRA-project site in Bitterfeld approaches for in situ remediation of multiple contaminants in groundwater are being tested. Alternatives in local implementation strategies as well as consequences of long-term restrictions for megasites like Bitterfeld need an independent evaluation of the situation using a risk-based approach. For this reason, a GIS-based 3D model of the area including geology, contaminants, hydrogeology, land-use and protected areas has been built. The regional groundwater pollution is characterized by contamination profiles of all monitored substances. In the area of investigation, e.g. threefold and fourfold threshold levels of chlorinated methane, ethane and ethene as well as HCH-isomers, mono-, di- and tetrachlorobenzene, DDT-isomers and benzene are frequently detected in groundwater, that means in at least 60% of the wells that were sampled. High median values of more than 10 microg/l were calculated for cis/trans-1,2-dichloroethene, 1,2-dichloroethane, chloroethene and monochlorobenzene. In general, the regional distribution of contaminants reflect the different sources and pathways, and give first results from a regional point of view, depending on a land-use classification of specific areas.

All coliforms are not created equal: A comparison of the effects of water source and in-house water contamination on Infantile Diarrheal Disease

NASA Astrophysics Data System (ADS)

VanDerslice, James; Briscoe, James

1993-07-01

Storing drinking water in the home is common in the developing world. Several studies have documented increased concentrations of fecal coliforms during household storage. This has led to the belief that in-house water contamination is an important transmission route for enteric pathogens and, moreover, that improving water source quality is not warranted until that quality can be maintained in the home. We contend that in-house water contamination does not pose a serious risk of diarrhea because family members would likely develop some level of immunity to pathogens commonly encountered in the household environment. Even when there is no such immunity, transmission of these pathogens via stored water may be inefficient relative to other household transmission routes, such as person-to-person contact or food contamination. A contaminated water source poses much more of a risk since it may introduce new pathogens into the household, The effects of water source and in-house contamination on diarrheal disease are estimated for 2355 Filipino infants. The results confirm our hypothesis: contaminated water sources pose a serious risk of diarrhea while contamination of drinking water in the home does not. Water boiling is shown to eliminate the risk of diarrhea due to water source contamination. The results imply that improvements in water source quality are more important than improving water storage practices.

Heterogeneity Effects in Plutonium Contaminated Soil

DTIC Science & Technology

2009-03-01

masses up to one kilogram once the ratio of Americium - 241 (Am- 241 ) and plutonium concentrations was established (Rademacher, 2001). Alpha...with a sample number and tared weight with a non-smearing marker. A standard control was then set using a point source of Americium - 241 on an aluminum...During the fire the weapons grade plutonium (Pu- 239, Pu-240, and Pu- 241 ) ignited and was released into the surrounding area, due to both

Nutrients and clam contamination by Escherichia coli in a meso-tidal coastal lagoon: Seasonal variation in counter cycle to external sources.

PubMed

Botelho, Maria João; Soares, Florbela; Matias, Domitília; Vale, Carlos

2015-07-15

The clam Ruditapes decussatus was transplanted from a natural recruitment area of Ria Formosa to three sites, surveyed for nutrients in water and sediments. Specimens were sampled monthly for determination of Escherichia coli, condition index and gonadal index. Higher nutrient values in low tide reflect drainage, anthropogenic sources or sediment regeneration, emphasising the importance of water mixing in the entire lagoon driven by the tide. Despite the increase of effluent discharges in summer due to tourism, nutrient concentrations and E. coli in clams were lower in warmer periods. The bactericide effect of temperature and solar radiation was better defined in clams from the inlet channel site than from sites closer to urban effluents. High temperature in summer and torrential freshwater inputs to Ria Formosa may anticipate climate change scenarios for south Europe. Seasonal variation of nutrients and clam contamination may thus point to possible alterations in coastal lagoons and their ecosystem services. Copyright © 2015. Published by Elsevier Ltd.

Reduction of nonpoint source contamination of surface water and groundwater by starch encapsulation of herbicides

USGS Publications Warehouse

Mills, M.S.; Thurman, E.M.

1994-01-01

The loss of the preemergent herbicide atrazine in surface runoff from experimental field plots growing corn (Zea mays L.) was significantly reduced using a starchencapsulated formulation versus a conventional powdered formulation. Field edge losses of starch-encapsulated atrazine were described as following a Rayleigh distribution totaling 1.8% of applied herbicide compared to exponential powdered atrazine losses of 2.9% applied - a 40% decrease. This has important implications for the reduction of nonpoint source contamination of surface water by agricultural chemicals. Unsaturated zone release of starchencapsulated atrazine was gradual, but comparable weed control was maintained. Deethylatrazine was a major dealkylated metabolite from each formulation, and deisopropylatrazine was a minor metabolite. The determination of soil partition coefficients for deethylatrazine and deisopropylatrazine (0.4 and 0.3, respectively), aqueous solubilities (3200 and 670 mg/L, respectively), and melting points (133 and 177 ??C, respectively) confirmed that the dealkylated metabolites should move more rapidly through the soil profile to groundwater than atrazine.

History of mercury use and environmental contamination at the Oak Ridge Y-12 Plant.

PubMed

Brooks, Scott C; Southworth, George R

2011-01-01

Between 1950 and 1963 approximately 11 million kilograms of mercury (Hg) were used at the Oak Ridge Y-12 National Security Complex (Y-12 NSC) for lithium isotope separation processes. About 3% of the Hg was lost to the air, soil and rock under facilities, and East Fork Poplar Creek (EFPC) which originates in the plant site. Smaller amounts of Hg were used at other Oak Ridge facilities with similar results. Although the primary Hg discharges from Y-12 NSC stopped in 1963, small amounts of Hg continue to be released into the creek from point sources and diffuse contaminated soil and groundwater sources within Y-12 NSC. Mercury concentration in EFPC has decreased 85% from ∼2000 ng/L in the 1980s. In general, methylmercury concentrations in water and in fish have not declined in response to improvements in water quality and exhibit trends of increasing concentration in some cases. Published by Elsevier Ltd.

An Assessment of Air As a Source of DNA Contamination Encountered When Performing PCR

PubMed Central

Witt, Nina; Rodger, Gillian; Vandesompele, Jo; Benes, Vladimir; Zumla, Alimuddin; Rook, Graham A.; Huggett, Jim F.

2009-01-01

Sensitive molecular methods, such as the PCR, can detect low-level contamination, and careful technique is required to reduce the impact of contaminants. Yet, some assays that are designed to detect high copy-number target sequences appear to be impossible to perform without contamination, and frequently, personnel or laboratory environment are held responsible as the source. This complicates diagnostic and research analysis when using molecular methods. To investigate the air specifically as a source of contamination, which might occur during PCR setup, we exposed tubes of water to the air of a laboratory and clean hood for up to 24 h. To increase the chances of contamination, we also investigated a busy open-plan office in the same way. All of the experiments showed the presence of human and rodent DNA contamination. However, there was no accumulation of the contamination in any of the environments investigated, suggesting that the air was not the source of contamination. Even the air from a busy open-plan office was a poor source of contamination for all of the DNA sequences investigated (human, bacterial, fungal, and rodent). This demonstrates that the personnel and immediate laboratory environment are not necessarily to blame for the observed contamination. PMID:19949694

Payload/orbiter contamination control assessment support

NASA Technical Reports Server (NTRS)

Rantanen, R. O.; Ress, E. B.

1975-01-01

The development and use is described of a basic contamination mathematical model of the shuttle orbiter which incorporates specific shuttle orbiter configurations and contamination sources. These configurations and sources were evaluated with respect to known shuttle orbiter operational surface characteristics and specific lines-of-sight which encompass the majority of viewing requirements for shuttle payloads. The results of these evaluations are presented as summary tables for each major source. In addition, contamination minimization studies were conducted and recommendations are made, where applicable, to support the shuttle orbiter design and operational planning for those sources which were identified to present a significant contamination threat.

40 CFR 144.12 - Prohibition of movement of fluid into underground sources of drinking water.

Code of Federal Regulations, 2010 CFR

2010-07-01

... other injection activity in a manner that allows the movement of fluid containing any contaminant into underground sources of drinking water, if the presence of that contaminant may cause a violation of any... source of drinking water indicates the movement of any contaminant into the underground source of...

Links between contaminant hotspots in low flow estuarine systems and altered sediment biogeochemical processes

NASA Astrophysics Data System (ADS)

Sutherland, Michael D.; Dafforn, Katherine A.; Scanes, Peter; Potts, Jaimie; Simpson, Stuart L.; Sim, Vivian X. Y.; Johnston, Emma L.

2017-11-01

The urbanisation of coastal zones is a major threat to the health of global estuaries and has been linked to increased contamination (e.g. metals) and excess organic matter. Urban stormwater networks collect and funnel contaminants into waterways at point sources (e.g. stormdrains). Under dry, low flow conditions, these stormwater contaminants can accumulate in sediments over time and result in modifications to benthic sediment biogeochemical processes. To quantify these processes, this field study measured differences in benthic metabolism (CR, GPP, NEM) and sediment-water nutrient fluxes (NH3, NOx, PO4) associated with stormdrains (0 m, 200 m and 1000 m away) and increased water-retention (embayments vs channels). Significant changes to benthic metabolism were detected with distance from stormdrains, and with differences in water-retention rates, above natural spatial and temporal variation. Oxygen consumption was ∼50% higher at stormdrains (0 m) compared to 1000 m away and >70% higher at stormdrains (0 m) located in embayments compared to channels. Oxygen production also appeared to decrease with distance from stormdrains in embayments, but patterns were variable. These changes to benthic metabolism were of a magnitude expected to influence benthic nutrient cycling, but NH3, NOx and PO4 fluxes were generally low, and highly spatially and temporally variable. Overall, metal (Cu) contamination explained most of the variation in sediment biogeochemical processes between embayments and channels, while sediment grain size explained differences in fluxes with distance from stormdrains. Importantly, although there was evidence of increased productivity associated with stormdrains, we also detected evidence of early hypoxia suggesting that systems with legacy stormwater contaminants exist on a tipping point. Future work should investigate changes to sediment processes after a major rainfall event, when large and sudden inputs of potentially toxic contaminants occur. Monitoring benthic O2 fluxes could be a sensitive measure of ecological change under these conditions.

Potential urban runoff impacts and contaminant distributions in shoreline and reservoir environments of Lake Havasu, southwestern United States.

PubMed

Wilson, Doyle C

2018-04-15

Heavy metal, nutrient, and hydrocarbon levels in and adjacent to Lake Havasu, a regionally significant water supply reservoir with a highly controlled, dynamic flow regime, are assessed in relation to possible stormwater runoff impacts from an arid urban center. Shallow groundwater and sediment analyses from ephemeral drainage (wash) mouths that convey stormwater runoff from Lake Havasu City, Arizona to the reservoir, provided contaminant control points and correlation ties with the reservoir environment. Fine-grain sediments tend to contain higher heavy metal concentrations whereas nutrients are more evenly distributed, except low total organic carbon levels from young wash mouth surfaces devoid of vegetation. Heavy metal and total phosphate sediment concentrations in transects from wash mouths into the reservoir have mixed and decreasing trends, respectively. Both series may indicate chemical depositional influences from urban runoff, yet no statistically significant concentration differences occur between specific wash mouths and corresponding offshore transects. Heavy metal pollution indices of all sediments indicate no discernible to minor contamination, indicating that runoff impacts are minimal. Nevertheless, several heavy metal concentrations from mid-reservoir sediment sites increase southward through the length of the reservoir. Continual significant water flow through the reservoir may help to disperse locally derived runoff particulates, which could mix and settle down gradient with chemical loads from upriver sources and local atmospheric deposition. Incorporating the shoreline environment with the reservoir investigation provides spatial continuity in assessing contaminant sources and distribution patterns. This is particularly acute in the investigation of energetic, flow-through reservoirs in which sources may be overlooked if solely analyzing the reservoir environment. Copyright © 2017 Elsevier B.V. All rights reserved.

High concentrations of heavy metals in neighborhoods near ore smelters in northern Mexico.

PubMed Central

Benin, A L; Sargent, J D; Dalton, M; Roda, S

1999-01-01

In developing countries, rapid industrialization without environmental controls has resulted in heavy metal contamination of communities. We hypothesized that residential neighborhoods located near ore industries in three northern Mexican cities would be heavily polluted with multiple contaminants (arsenic, cadmium, and lead) and that these sites would be point sources for the heavy metals. To evaluate these hypotheses, we obtained samples of roadside surface dust from residential neighborhoods within 2 m of metal smelters [Torreón (n = 19)] and Chihuahua (n = 19)] and a metal refinery [Monterrey (n = 23)]. Heavy metal concentrations in dust were mapped with respect to distance from the industrial sites. Correlation between dust metal concentration and distance was estimated with least-squares regression using log-transformed data. Median dust arsenic, cadmium, and lead concentrations were 32, 10, and 277 microg/g, respectively, in Chihuahua; 42, 2, and 467 microg/g, respectively, in Monterrey, and 113, 112, and 2,448 microg/g, respectively, in Torreón. Dust concentrations of all heavy metals were significantly higher around the active smelter in Torreón, where more than 90% of samples exceeded Superfund cleanup goals. At all sites, dust concentrations were inversely related to distance from the industrial source, implicating these industries as the likely source of the contamination. We concluded that residential neighborhoods around metal smelting and refining sites in these three cities are contaminated by heavy metals at concentrations likely to pose a health threat to people living nearby. Evaluations of human exposure near these sites should be conducted. Because multiple heavy metal pollutants may exist near smelter sites, researchers should avoid attributing toxicity to one heavy metal unless others have been measured and shown not to coexist. Images Figure 1 Figure 2-3 Figure 4-5 Figure 6-7 Figure 8 PMID:10090706

Source Evaluation and Trace Metal Contamination in Benthic Sediments from Equatorial Ecosystems Using Multivariate Statistical Techniques

PubMed Central

Benson, Nsikak U.; Asuquo, Francis E.; Williams, Akan B.; Essien, Joseph P.; Ekong, Cyril I.; Akpabio, Otobong; Olajire, Abaas A.

2016-01-01

Trace metals (Cd, Cr, Cu, Ni and Pb) concentrations in benthic sediments were analyzed through multi-step fractionation scheme to assess the levels and sources of contamination in estuarine, riverine and freshwater ecosystems in Niger Delta (Nigeria). The degree of contamination was assessed using the individual contamination factors (ICF) and global contamination factor (GCF). Multivariate statistical approaches including principal component analysis (PCA), cluster analysis and correlation test were employed to evaluate the interrelationships and associated sources of contamination. The spatial distribution of metal concentrations followed the pattern Pb>Cu>Cr>Cd>Ni. Ecological risk index by ICF showed significant potential mobility and bioavailability for Cu, Cu and Ni. The ICF contamination trend in the benthic sediments at all studied sites was Cu>Cr>Ni>Cd>Pb. The principal component and agglomerative clustering analyses indicate that trace metals contamination in the ecosystems was influenced by multiple pollution sources. PMID:27257934

Assessing the Impact of Source-Zone Remediation Efforts at the Contaminant-Plume Scale Through Analysis of Contaminant Mass Discharge

PubMed Central

Brusseau, M. L.; Hatton, J.; DiGuiseppi, W.

2011-01-01

The long-term impact of source-zone remediation efforts was assessed for a large site contaminated by trichloroethene. The impact of the remediation efforts (soil vapor extraction and in-situ chemical oxidation) was assessed through analysis of plume-scale contaminant mass discharge, which was measured using a high-resolution data set obtained from 23 years of operation of a large pump-and-treat system. The initial contaminant mass discharge peaked at approximately 7 kg/d, and then declined to approximately 2 kg/d. This latter value was sustained for several years prior to the initiation of source-zone remediation efforts. The contaminant mass discharge in 2010, measured several years after completion of the two source-zone remediation actions, was approximately 0.2 kg/d, which is ten times lower than the value prior to source-zone remediation. The time-continuous contaminant mass discharge data can be used to evaluate the impact of the source-zone remediation efforts on reducing the time required to operate the pump-and-treat system, and to estimate the cost savings associated with the decreased operational period. While significant reductions have been achieved, it is evident that the remediation efforts have not completely eliminated contaminant mass discharge and associated risk. Remaining contaminant mass contributing to the current mass discharge is hypothesized to comprise poorly-accessible mass in the source zones, as well as aqueous (and sorbed) mass present in the extensive lower-permeability units located within and adjacent to the contaminant plume. The fate of these sources is an issue of critical import to the remediation of chlorinated-solvent contaminated sites, and development of methods to address these sources will be required to achieve successful long-term management of such sites and to ultimately transition them to closure. PMID:22115080

Tracking enteric viruses in green vegetables from central Argentina: potential association with viral contamination of irrigation waters.

PubMed

Prez, V E; Martínez, L C; Victoria, M; Giordano, M O; Masachessi, G; Ré, V E; Pavan, J V; Colina, R; Barril, P A; Nates, S V

2018-05-11

Consumption of green vegetable products is commonly viewed as a potential risk factor for infection with enteric viruses. The link between vegetable crops and fecally contaminated irrigation water establishes an environmental scenario that can result in a risk to human health. The aim of this work was to analyze the enteric viral quality in leafy green vegetables from Córdoba (Argentina) and its potential association with viral contamination of irrigation waters. During July-December 2012, vegetables were collected from peri-urban green farms (n = 19) and its corresponding urban river irrigation waters (n = 12). Also, urban sewage samples (n = 6) were collected to analyze the viral variants circulating in the community. Viruses were eluted and concentrated by polyethylene glycol precipitation and then were subject to Reverse Transcription Polymerase Chain Reaction to assess the genome presence of norovirus, rotavirus and human astrovirus. The concentrates were also inoculated in HEp-2 (Human Epidermoid carcinoma strain #2) cells to monitor the occurrence of infective enterovirus. The frequency of detection of the viral groups in sewage, irrigation water and crops was: norovirus 100%, 67% and 58%, rotavirus 100%, 75% and 5%, astrovirus 83%, 75% and 32% and infective enterovirus 50%, 33% and 79%, respectively. A similar profile in sewage, irrigation water and green vegetables was observed for norovirus genogroups (I and II) distribution as well as for rotavirus and astrovirus G-types. These results provide the first data for Argentina pointing out that green leafy vegetables are contaminated with a broad range of enteric viruses and that the irrigation water would be a source of contamination. The presence of viral genomes and infective particles in food that in general suffer minimal treatment before consumption underlines that green crops can act as potential sources of enteric virus transmission. Public intervention in the use of the river waters as irrigation source is needed. Copyright © 2018. Published by Elsevier B.V.

Drinking cholera: salinity levels and palatability of drinking water in coastal Bangladesh.

PubMed

Grant, Stephen Lawrence; Tamason, Charlotte Crim; Hoque, Bilqis Amin; Jensen, Peter Kjaer Mackie

2015-04-01

To measure the salinity levels of common water sources in coastal Bangladesh and explore perceptions of water palatability among the local population to investigate the plausibility of linking cholera outbreaks in Bangladesh with ingestion of saline-rich cholera-infected river water. Hundred participants took part in a taste-testing experiment of water with varying levels of salinity. Salinity measurements were taken of both drinking and non-drinking water sources. Informal group discussions were conducted to gain an in-depth understanding of water sources and water uses. Salinity levels of non-drinking water sources suggest that the conditions for Vibrio cholerae survival exist 7-8 days within the local aquatic environment. However, 96% of participants in the taste-testing experiment reported that they would never drink water with salinity levels that would be conducive to V. cholerae survival. Furthermore, salinity levels of participant's drinking water sources were all well below the levels required for optimal survival of V. cholerae. Respondents explained that they preferred less salty and more aesthetically pleasing drinking water. Theoretically, V. cholerae can survive in the river systems in Bangladesh; however, water sources which have been contaminated with river water are avoided as potential drinking water sources. Furthermore, there are no physical connecting points between the river system and drinking water sources among the study population, indicating that the primary driver for cholera cases in Bangladesh is likely not through the contamination of saline-rich river water into drinking water sources. © 2015 John Wiley & Sons Ltd.

Analysis of concentration fluctuations in gas dispersion around high-rise building for different incident wind directions.

PubMed

Liu, X P; Niu, J L; Kwok, K C S

2011-09-15

This article presents experimental results that illustrate the unsteady characteristics of gas dispersion around a complex-shaped high-rise building for different incident wind directions. A series of wind tunnel experiments were conducted using a 1:30 scale model that represented the real structures under study. The objective of this paper is to study the behaviour of concentration fluctuations through transient analysis. Tracer gas was continuously released from a point source located at different positions, and a time series of fluctuating concentrations were recorded at a large number of points using fast flame ionization detectors. The experimental data were analysed to provide a comprehensive data set including variances and associated statistical quantities. Both the unsteady characteristics of the system and their potential practical impact are presented and discussed. Under crowd living conditions, the air pollutant exhausted from one household could probably re-enter into the neighbouring households, traveling with ambient airflow. Such pollutant dispersion process is defined as air cross-contamination in this study. The results indicate that the wind-induced cross-contamination around the studied type of high-rise building should not be overlooked, and the fluctuating concentrations should be paid attention to particularly during the evaluation of a potential contamination risk. This study can help deepen our understanding of the mechanisms of air cross-contamination, and will be useful for implementing optimization strategies to improve the built environments in metropolitan cities such as Hong Kong. Copyright © 2011 Elsevier B.V. All rights reserved.

Urban stormwater harvesting and reuse: a probe into the chemical, toxicology and microbiological contaminants in water quality.

PubMed

Chong, Meng Nan; Sidhu, Jatinder; Aryal, Rupak; Tang, Janet; Gernjak, Wolfgang; Escher, Beate; Toze, Simon

2013-08-01

Stormwater is one of the last major untapped urban water resources that can be exploited as an alternative water source in Australia. The information in the current Australian Guidelines for Water Recycling relating to stormwater harvesting and reuse only emphasises on a limited number of stormwater quality parameters. In order to supply stormwater as a source for higher value end-uses, a more comprehensive assessment on the potential public health risks has to be undertaken. Owing to the stochastic variations in rainfall, catchment hydrology and also the types of non-point pollution sources that can provide contaminants relating to different anthropogenic activities and catchment land uses, the characterisation of public health risks in stormwater is complex, tedious and not always possible through the conventional detection and analytical methods. In this study, a holistic approach was undertaken to assess the potential public health risks in urban stormwater samples from a medium-density residential catchment. A combined chemical-toxicological assessment was used to characterise the potential health risks arising from chemical contaminants, while a combination of standard culture methods and quantitative polymerase chain reaction (qPCR) methods was used for detection and quantification of faecal indicator bacteria (FIB) and pathogens in urban stormwater. Results showed that the concentration of chemical contaminants and associated toxicity were relatively low when benchmarked against other alternative water sources such as recycled wastewater. However, the concentrations of heavy metals particularly cadmium and lead have exceeded the Australian guideline values, indicating potential public health risks. Also, high numbers of FIB were detected in urban stormwater samples obtained from wet weather events. In addition, qPCR detection of human-related pathogens suggested there are frequent sewage ingressions into the urban stormwater runoff during wet weather events. Further water quality monitoring study will be conducted at different contrasting urban catchments in order to undertake a more comprehensive public health risk assessment for urban stormwater.

Seasonal Shifts in Primary Water Source Type: A Comparison of Largely Pastoral Communities in Uganda and Tanzania

PubMed Central

Pearson, Amber L.; Zwickle, Adam; Namanya, Judith; Rzotkiewicz, Amanda; Mwita, Emiliana

2016-01-01

Many water-related illnesses show an increase during the wet season. This is often due to fecal contamination from runoff, yet, it is unknown whether seasonal changes in water availability may also play a role in increased illness via changes in the type of primary water source used by households. Very little is known about the dynamic aspects of access to water and changes in source type across seasons, particularly in semi-arid regions with annual water scarcity. The research questions in this study were: (1) To what degree do households in Uganda (UG) and Tanzania (TZ) change primary water source type between wet and dry seasons?; and (2) How might seasonal changes relate to water quality and health? Using spatial survey data from 92 households each in UG and TZ this study found that, from wet to dry season, 26% (UG) and 9% (TZ) of households switched from a source with higher risk of contamination to a source with lower risk. By comparison, only 20% (UG) and 0% (TZ) of households switched from a source with lower risk of contamination to a source with higher risk of contamination. This research suggests that one pathway through which water-related disease prevalence may differ across seasons is the use of water sources with higher risk contamination, and that households with access to sources with lower risks of contamination sometimes choose to use more contaminated sources. PMID:26828507

Development of phytotoxicity tests using wetland species

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nelson, M.K.; Fairchild, J.F.

1994-12-31

Laboratory phytotoxicity tests used to assess contaminant effects may not effectively protect wetland communities. The authors are developing routine culture and testing methods for selected fresh water plants, that can be used in risk assessments and monitoring of existing wetland systems. Utility of these tests includes evaluating the effects of point or non-point source contamination that may cause water or sediment quality degradation. Selected species include algae (blue-green, green), phytoflagellates (Chlamydomonas, Euglena), and floating or submerged vascular plants (milfoil, coontail, wild celery, elodea, duckweed). Algae toxicity tests range from 2-d, 4-d, and 7 day tests, and macrophyte tests from 10-dmore » to 14 days. Metribuzin and boron are the selected contaminants for developing the test methods. Metribuzin, a triazinone herbicide, is a photosystem 11 inhibitor, and is commonly used for control of grass and broad-leaf plants. As a plant micronutrient, boron is required in very small amounts, but excessive levels can result in phytotoxicity or accumulation. The investigations focus on the influence of important factors including the influence of light quality and quantity, and nutrient media. Reference toxicant exposures with potassium chloride are used to establish baseline data for sensitivity and vitality of the plants. These culture and test methods will be incorporated into recommendations for standard phytotoxicity test designs.« less

Implications of new data on lead toxicity for managing and preventing exposure.

PubMed Central

Silbergeld, E K

1990-01-01

Recent advances in research on low-level lead poisoning point to the need to increase efforts to prevent exposure. Current biomedical consensus accepts that blood lead levels as low as 5 to 15 mcg/dL are risky to fetuses, young children, and adults. Lead at low dose is associated with increased blood pressure in adults, and chronic exposure has been associated in cohort studies with kidney disease and cancer. Data on lead toxicokinetics also points to the hazards of low-level, chronic exposure, since the lead that is accumulated over time in bone can be released at a relatively rapid rate during pregnancy and menopause. Sources that contribute to current lead exposure of the general population include unabated lead-based paint and contaminated soils, as well as lower level but pervasive sources in drinking water, food, and consumer products. PMID:2088754

Implications of new data on lead toxicity for managing and preventing exposure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Silbergeld, E.K.

1990-11-01

Recent advances in research on low-level lead poisoning point to the need to increase efforts to prevent exposure. Current biomedical consensus accepts that blood lead levels as low as 5 to 15 mcg/dL are risky to fetuses, young children, and adults. Lead at low dose is associated with increased blood pressure in adults, and chronic exposure has been associated in cohort studies with kidney disease and cancer. Data on lead toxicokinetics also points to the hazards of low-level, chronic exposure, since the lead that is accumulated over time in bone can be released at a relatively rapid rate during pregnancymore » and menopause. Sources that contribute to current lead exposure of the general population include unabated lead-based paint and contaminated soils, as well as lower level but pervasive sources in drinking water, food, and consumer products.« less

Occurrence of bacteriophages infecting Aeromonas, Enterobacter, and Klebsiella in water and association with contamination sources in Thailand.

PubMed

Wangkahad, Bencharong; Bosup, Suchada; Mongkolsuk, Skorn; Sirikanchana, Kwanrawee

2015-06-01

The co-residence of bacteriophages and their bacterial hosts in humans, animals, and environmental sources directed the use of bacteriophages to track the origins of the pathogenic bacteria that can be found in contaminated water. The objective of this study was to enumerate bacteriophages of Aeromonas caviae (AecaKS148), Enterobacter sp. (EnspKS513), and Klebsiella pneumoniae (KlpnKS648) in water and evaluate their association with contamination sources (human vs. animals). Bacterial host strains were isolated from untreated wastewater in Bangkok, Thailand. A double-layer agar technique was used to detect bacteriophages. All three bacteriophages were detected in polluted canal samples, with likely contamination from human wastewater, whereas none was found in non-polluted river samples. AecaKS148 was found to be associated with human fecal sources, while EnspKS513 and KlpnKS648 seemed to be equally prevalent in both human and animal fecal sources. Both bacteriophages were also present in polluted canals that could receive contamination from other fecal sources or the environment. In conclusion, all three bacteriophages were successfully monitored in Bangkok, Thailand. This study provided an example of bacteriophages for potential use as source identifiers of pathogen contamination. The results from this study will assist in controlling sources of pathogen contamination, especially in developing countries.

Oxidation of Ammonia in Source Water Using Biological Filtration (slides)

EPA Science Inventory

Drinking water utilities are challenged with a variety of contamination issues from both the source water and the distribution system. Source water issues include biological contaminants such as bacteria and viruses as well as inorganic contaminants such as arsenic, barium, and ...

Non-destructive in-situ method and apparatus for determining radionuclide depth in media

DOEpatents

Xu, X. George; Naessens, Edward P.

2003-01-01

A non-destructive method and apparatus which is based on in-situ gamma spectroscopy is used to determine the depth of radiological contamination in media such as concrete. An algorithm, Gamma Penetration Depth Unfolding Algorithm (GPDUA), uses point kernel techniques to predict the depth of contamination based on the results of uncollided peak information from the in-situ gamma spectroscopy. The invention is better, faster, safer, and/cheaper than the current practice in decontamination and decommissioning of facilities that are slow, rough and unsafe. The invention uses a priori knowledge of the contaminant source distribution. The applicable radiological contaminants of interest are any isotopes that emit two or more gamma rays per disintegration or isotopes that emit a single gamma ray but have gamma-emitting progeny in secular equilibrium with its parent (e.g., .sup.60 Co, .sup.235 U, and .sup.137 Cs to name a few). The predicted depths from the GPDUA algorithm using Monte Carlo N-Particle Transport Code (MCNP) simulations and laboratory experiments using .sup.60 Co have consistently produced predicted depths within 20% of the actual or known depth.

The effect of water contamination on the dew-point temperature scale realization with humidity generators

NASA Astrophysics Data System (ADS)

Vilbaste, M.; Heinonen, M.; Saks, O.; Leito, I.

2013-08-01

The purpose of this paper is to study the effect of contaminated water in the context of humidity generators. Investigation of different methods to determine the drop in dew-point temperature due to contamination and experiments on actual contamination rates are reported. Different methods for calculating the dew-point temperature effect from electrical conductivity and density measurements are studied with high-purity water and aqueous solutions of NaCl and LiCl. The outcomes of the calculation methods are compared with the results of direct humidity measurements. The results show that the often applied Raoult's law based calculation method is in good agreement with other methods. For studying actual contamination, water samples were kept in glass, plastic, copper and stainless-steel vessels for up to 13 months to investigate natural ionic and organic contamination in vessels with different wall materials. The amount of ionic contamination was found to be higher in copper and glass vessels than in stainless-steel and plastic vessels. The amount of organic contamination was found to be highest in the plastic vessel. In all the cases, however, the corresponding drop in dew-point temperature due to natural contamination was found to be below 0.1 mK. The largest rate of change of dew-point temperature was 26 µK/month. Thus, if proper cleanness is maintained in a humidity generator the effect of contamination of water in the saturator is insignificant compared with the major uncertainty components even in the most accurate generators today.

Impact of Some Ecological Factors on Fecal Contamination of Drinking Water by Diarrheagenic Antibiotic-Resistant Escherichia coli in Zagazig City, Egypt

PubMed Central

Gohar, Maha Kamal; Atta, Amal Hassan

2016-01-01

Fecal contamination of drinking water is a major health problem which accounts for many cases of diarrhea mainly in infants and foreigners. This contamination is a complex interaction of many parameters. Antibiotic resistance among bacterial isolates complicates the problem. The study was done to identify fecal contamination of drinking water by Diarrheagenic Antibiotic-Resistant Escherichia coli in Zagazig city and to trace reasons for such contamination, three hundred potable water samples were investigated for E. coli existence. Locations of E. coli positive samples were investigated in relation to population density, water source, and type of water pipe. Sixteen E. coli strains were isolated. Antibiotic sensitivity was done and enterotoxigenic, enteropathogenic, and enterohaemorrhagic virulence genes were investigated by PCR. Probability of fecal contamination correlated with higher population density, with increased distance from Zagazig water plant, and with asbestos cement water pipes. Resistance to at least one antimicrobial drug was found in all isolates. Virulence genes were detected in a rate of 26.27%, 13.13%, 20%, 6.67%, and 33.33% for LT, ST, stx1, stx2, and eae genes, respectively. This relatively high frequency of fecal contamination points towards the high risk of developing diarrhea by antibiotic resistant DEC in low socioeconomic communities particularly with old fashion distribution systems. PMID:27725834

Associations of free-living bacteria and dissolved organic compounds in a plume of contaminated groundwater

USGS Publications Warehouse

Harvey, Ronald W.; Barber, Larry B.

1992-01-01

Associations of free-living bacteria (FLB) and dissolved organic contaminants in a 4-km-long plume of sewage-contaminated groundwater were investigated. Abundance of FLB in the core of the plume (as delineated by maximum specific conductance) steadily decreased in the direction of flow from a point 0.25 km downgradient from the source to the toe of the plume. At 0.25 km downgradient, FLB comprised up to 31% of the total bacterial population, but constituted <7% of the population at 2 km downgradient. Abundance of FLB correlated strongly (r = 0.80, n = 23) with total dissolved organic carbon (DOC) in contaminated groundwater between 0.64 and 2.1 km downgradient, although distributions of individual contaminants such as di-, tri- and tetrachloroethene were highly variable, and their association with FLB less clear. Numbers of FLB in the downgradient portion of the plume which is contaminated with branched-chain alkylbenzenesulfonate (ABS) surfactants were low (<5 · 108/L) in spite of relatively high levels of DOC (up to 4 mg/L). However, abundance of FLB correlated strongly with non-surfactant DOC along vertical transects through the plume. The ratio of FLB to DOC and the ratio of FLB to attached bacteria generally decreased in the direction of flow and, consequently, with the age of the organic contaminants.

Use of Spatial Sampling and Microbial Source-Tracking Tools for Understanding Fecal Contamination at Two Lake Erie Beaches

USGS Publications Warehouse

Francy, Donna S.; Bertke, Erin E.; Finnegan, Dennis P.; Kephart, Christopher M.; Sheets, Rodney A.; Rhoades, John; Stumpe, Lester

2006-01-01

Source-tracking tools were used to identify potential sources of fecal contamination at two Lake Erie bathing beaches: an urban beach (Edgewater in Cleveland, Ohio) and a beach in a small city (Lakeshore in Ashtabula, Ohio). These tools included identifying spatial patterns of Escherichia coli (E. coli) concentrations in each area, determining weather patterns that caused elevated E. coli, and applying microbial source tracking (MST) techniques to specific sites. Three MST methods were used during this study: multiple antibiotic resistance (MAR) indexing of E. coli isolates and the presence of human-specific genetic markers within two types of bacteria, the genus Bacteroides and the species Enterococcus faecium. At Edgewater, sampling for E. coli was done during 2003-05 at bathing-area sites, at nearshore lake sites, and in shallow ground water in foreshore and backshore areas. Spatial sampling at nearshore lake sites showed that fecal contamination was most likely of local origin; E. coli concentrations near the mouths of rivers and outfalls remote to the beach were elevated (greater than 235 colony-forming units per 100 milliliters (CFU/100 mL)) but decreased along transport pathways to the beach. In addition, E. coli concentrations were generally highest in bathing-area samples collected at 1- and 2-foot water depths, midrange at 3-foot depths, and lowest in nearshore lake samples typically collected 150 feet from the shoreline. Elevated E. coli concentrations at bathing-area sites were generally associated with increased wave heights and rainfall, but not always. E. coli concentrations were often elevated in shallow ground-water samples, especially in samples collected less than 10 feet from the edge of water (near foreshore area). The interaction of shallow ground water and waves may be a mechanism of E. coli storage and accumulation in foreshore sands. Infiltration of bird feces through sand with surface water from rainfall and high waves may be concentrating E. coli in shallow ground water in foreshore and backshore sands. At Lakeshore, sampling for E. coli was done at bathing-area, nearshore lake, and parking-lot sites during 2004-05. Low concentrations of E. coli at nearshore lake sites furthest from the shoreline indicated that fecal contamination was most likely of local origin. High concentrations of E. coli in water and bed sediments at several nearshore lake sites showed that contamination was emanating from several points along the shoreline during wet and dry weather, including the boat ramp, an area near the pond drainage, and parking-lot sediments. Physical evidence confirmed that runoff from the parking lot leads to degradation of water quality at the beach. MST samples were collected to help interpret spatial findings and determine whether sources of fecal contamination were from wastewater or bird feces and if a human-specific marker was present. MAR indices were useful in distinguishing between bird feces and wastewater sources because they were about 10 times higher in the latter. The results from MAR indices agreed with results from the two human-specific markers in some but not all of the samples tested. Bacteroides and enterococci human-specific markers were found on one day at Edgewater and two days at Lakeshore. On three days at Edgewater and two days at Lakeshore, the MAR index indicated a mixed source, but neither marker was found in bathing-water samples; this may be because bacterial indicator concentrations were too low to detect a marker. Multiple tools are needed to help identify sources of fecal contamination at coastal beaches. Spatial sampling identified patterns in E. coli concentrations and yielded information on the physical pathways of contamination. MST methods provided information on whether the source was likely of human or nonhuman origin only; however, MST did not provide information on the pathways of contamination.

Beach boundary layer: a framework for addressing recreational water quality impairment at enclosed beaches.

PubMed

Grant, Stanley B; Sanders, Brett F

2010-12-01

Nearshore waters in bays, harbors, and estuaries are frequently contaminated with human pathogens and fecal indicator bacteria. Tracking down and mitigating this contamination is complicated by the many point and nonpoint sources of fecal pollution that can degrade water quality along the shore. From a survey of the published literature, we propose a conceptual and mathematical framework, the "beach boundary layer model", for understanding and quantifying the relative impact of beach-side and bay-side sources of fecal pollution on nearshore water quality. In the model, bacterial concentration in ankle depth water C(ankle) [bacteria L(-3)] depends on the flux m'' [bacteria L(-2) T(-1)] of fecal bacteria from beach-side sources (bather shedding, bird and dog feces, tidal washing of sediments, decaying vegetation, runoff from small drains, and shallow groundwater discharge), a cross-shore mass transfer velocity k [L T(-1)] that accounts for the physics of nearshore transport and mixing, and a background concentration C(bay) [bacteria L(-3)] attributable to bay-side sources of pollution that impact water quality over large regions (sewage outfalls, creeks and rivers): C(ankle) = m''/k + C(bay). We demonstrate the utility of the model for identifying risk factors and pollution sources likely to impact shoreline water quality, and evaluate the model's underlying assumptions using computational fluid dynamic simulations of flow, turbulence, and mass transport in a trapezoidal channel.

Isotopic Tracing of Groundwater Contamination: Techniques, Applications, and Considerations, February 24/25, 2011

EPA Pesticide Factsheets

We need techniques that verify that groundwater is not contaminated from hydraulic fracturing. Groundwater contamination can come from sources which may carry a fingerprint that identifies the source, or the process which led to the contamination.

Semi-quantitative evaluation of fecal contamination potential by human and ruminant sources using multiple lines of evidence.

PubMed

Stoeckel, Donald M; Stelzer, Erin A; Stogner, Robert W; Mau, David P

2011-05-01

Protocols for microbial source tracking of fecal contamination generally are able to identify when a source of contamination is present, but thus far have been unable to evaluate what portion of fecal-indicator bacteria (FIB) came from various sources. A mathematical approach to estimate relative amounts of FIB, such as Escherichia coli, from various sources based on the concentration and distribution of microbial source tracking markers in feces was developed. The approach was tested using dilute fecal suspensions, then applied as part of an analytical suite to a contaminated headwater stream in the Rocky Mountains (Upper Fountain Creek, Colorado). In one single-source fecal suspension, a source that was not present could not be excluded because of incomplete marker specificity; however, human and ruminant sources were detected whenever they were present. In the mixed-feces suspension (pet and human), the minority contributor (human) was detected at a concentration low enough to preclude human contamination as the dominant source of E. coli to the sample. Without the semi-quantitative approach described, simple detects of human-associated marker in stream samples would have provided inaccurate evidence that human contamination was a major source of E. coli to the stream. In samples from Upper Fountain Creek the pattern of E. coli, general and host-associated microbial source tracking markers, nutrients, and wastewater-associated chemical detections--augmented with local observations and land-use patterns--indicated that, contrary to expectations, birds rather than humans or ruminants were the predominant source of fecal contamination to Upper Fountain Creek. This new approach to E. coli allocation, validated by a controlled study and tested by application in a relatively simple setting, represents a widely applicable step forward in the field of microbial source tracking of fecal contamination. Copyright © 2011 Elsevier Ltd. All rights reserved.

Using Geophysical Signatures to Investigate Temporal Changes Due to Source Reduction in the Subsurface Contaminated with Hydrocarbons

EPA Science Inventory

We investigated the geophysical response to subsurface hydrocarbon contamination source removal. Source removal by natural attenuation or by engineered bioremediation is expected to change the biological, chemical, and physical environment associated with the contaminated matrix....

The Anisotropy of the Microwave Background to l=3500: Mosaic Observations with the Cosmic Background Imager

NASA Technical Reports Server (NTRS)

Pearson, T. J.; Mason, B. S.; Readhead, A. C. S.; Shepherd, M. C.; Sievers, J. L.; Udomprasert, P. S.; Cartwright, J. K.; Farmer, A. J.; Padin, S.; Myers, S. T.;

The Grand Challenge of Basin-Scale Groundwater Quality Management Modelling

NASA Astrophysics Data System (ADS)

Fogg, G. E.

2017-12-01

The last 50+ years of agricultural, urban and industrial land and water use practices have accelerated the degradation of groundwater quality in the upper portions of many major aquifer systems upon which much of the world relies for water supply. In the deepest and most extensive systems (e.g., sedimentary basins) that typically have the largest groundwater production rates and hold fresh groundwaters on decadal to millennial time scales, most of the groundwater is not yet contaminated. Predicting the long-term future groundwater quality in such basins is a grand scientific challenge. Moreover, determining what changes in land and water use practices would avert future, irreversible degradation of these massive freshwater stores is a grand challenge both scientifically and societally. It is naïve to think that the problem can be solved by eliminating or reducing enough of the contaminant sources, for human exploitation of land and water resources will likely always result in some contamination. The key lies in both reducing the contaminant sources and more proactively managing recharge in terms of both quantity and quality, such that the net influx of contaminants is sufficiently moderate and appropriately distributed in space and time to reverse ongoing groundwater quality degradation. Just as sustainable groundwater quantity management is greatly facilitated with groundwater flow management models, sustainable groundwater quality management will require the use of groundwater quality management models. This is a new genre of hydrologic models do not yet exist, partly because of the lack of modeling tools and the supporting research to model non-reactive as well as reactive transport on large space and time scales. It is essential that the contaminant hydrogeology community, which has heretofore focused almost entirely on point-source plume-scale problems, direct it's efforts toward the development of process-based transport modeling tools and analyses capable of appropriately upscaling advection-dispersion and reactions at the basin scale (10^2 km). A road map for research and development in groundwater quality management modeling and its application toward securing future groundwater resources will be discussed.

Quantitative farm-to-fork risk assessment model for norovirus and hepatitis A virus in European leafy green vegetable and berry fruit supply chains.

PubMed

Bouwknegt, Martijn; Verhaelen, Katharina; Rzeżutka, Artur; Kozyra, Iwona; Maunula, Leena; von Bonsdorff, Carl-Henrik; Vantarakis, Apostolos; Kokkinos, Petros; Petrovic, Tamas; Lazic, Sava; Pavlik, Ivo; Vasickova, Petra; Willems, Kris A; Havelaar, Arie H; Rutjes, Saskia A; de Roda Husman, Ana Maria

2015-04-02

Fresh produce that is contaminated with viruses may lead to infection and viral gastroenteritis or hepatitis when consumed raw. It is thus important to reduce virus numbers on these foods. Prevention of virus contamination in fresh produce production and processing may be more effective than treatment, as sufficient virus removal or inactivation by post-harvest treatment requires high doses that may adversely affect food quality. To date knowledge of the contribution of various potential contamination routes is lacking. A risk assessment model was developed for human norovirus, hepatitis A virus and human adenovirus in raspberry and salad vegetable supply chains to quantify contributions of potential contamination sources to the contamination of produce at retail. These models were used to estimate public health risks. Model parameterization was based on monitoring data from European supply chains and literature data. No human pathogenic viruses were found in the soft fruit supply chains; human adenovirus (hAdV) was detected, which was additionally monitored as an indicator of fecal pollution to assess the contribution of potential contamination points. Estimated risks per serving of lettuce based on the models were 3×10(-4) (6×10(-6)-5×10(-3)) for NoV infection and 3×10(-8) (7×10(-10)-3×10(-6)) for hepatitis A jaundice. The contribution to virus contamination of hand-contact was larger as compared with the contribution of irrigation, the conveyor belt or the water used for produce rinsing. In conclusion, viral contamination in the lettuce and soft fruit supply chains occurred and estimated health risks were generally low. Nevertheless, the 97.5% upper limit for the estimated NoV contamination of lettuce suggested that infection risks up to 50% per serving might occur. Our study suggests that attention to full compliance for hand hygiene will improve fresh produce safety related to virus risks most as compared to the other examined sources, given the monitoring results. This effect will be further aided by compliance with other hygiene and water quality regulations in production and processing facilities. Copyright © 2015 Elsevier B.V. All rights reserved.

Primary Beam Air Kerma Dependence on Distance from Cargo and People Scanners

DOE Office of Scientific and Technical Information (OSTI.GOV)

Strom, Daniel J.; Cerra, Frank

The distance dependence of air kerma or dose rate of the primary radiation beam is not obvious for security scanners of cargo and people in which there is relative motion between a collimated source and the person or object being imaged. To study this problem, one fixed line source and three moving-source scan-geometry cases are considered, each characterized by radiation emanating perpendicular to an axis. The cases are 1) a stationary line source of radioactive material, e.g., contaminated solution in a pipe; 2) a moving, uncollimated point source of radiation that is shuttered or off when it is stationary; 3)more » a moving, collimated point source of radiation that is shuttered or off when it is stationary; and 4) a translating, narrow “pencil” beam emanating in a flying-spot, raster pattern. Each case is considered for short and long distances compared to the line source length or path traversed by a moving source. The short distance model pertains mostly to dose to objects being scanned and personnel associated with the screening operation. The long distance model pertains mostly to potential dose to bystanders. For radionuclide sources, the number of nuclear transitions that occur a) per unit length of a line source, or b) during the traversal of a point source, is a unifying concept. The “universal source strength” of air kerma rate at a meter from the source can be used to describe x-ray machine or radionuclide sources. For many cargo and people scanners with highly collimated fan or pencil beams, dose varies as the inverse of the distance from the source in the near field and with the inverse square of the distance beyond a critical radius. Ignoring the inverse square dependence and using inverse distance dependence is conservative in the sense of tending to overestimate dose.« less

Primary Beam Air Kerma Dependence on Distance from Cargo and People Scanners.

PubMed

Strom, Daniel J; Cerra, Frank

2016-06-01

The distance dependence of air kerma or dose rate of the primary radiation beam is not obvious for security scanners of cargo and people in which there is relative motion between a collimated source and the person or object being imaged. To study this problem, one fixed line source and three moving-source scan-geometry cases are considered, each characterized by radiation emanating perpendicular to an axis. The cases are 1) a stationary line source of radioactive material, e.g., contaminated solution in a pipe; 2) a moving, uncollimated point source of radiation that is shuttered or off when it is stationary; 3) a moving, collimated point source of radiation that is shuttered or off when it is stationary; and 4) a translating, narrow "pencil" beam emanating in a flying-spot, raster pattern. Each case is considered for short and long distances compared to the line source length or path traversed by a moving source. The short distance model pertains mostly to dose to objects being scanned and personnel associated with the screening operation. The long distance model pertains mostly to potential dose to bystanders. For radionuclide sources, the number of nuclear transitions that occur a) per unit length of a line source or b) during the traversal of a point source is a unifying concept. The "universal source strength" of air kerma rate at 1 m from the source can be used to describe x-ray machine or radionuclide sources. For many cargo and people scanners with highly collimated fan or pencil beams, dose varies as the inverse of the distance from the source in the near field and with the inverse square of the distance beyond a critical radius. Ignoring the inverse square dependence and using inverse distance dependence is conservative in the sense of tending to overestimate dose.

Contamination history of lead and other trace metals reconstructed from an urban winter pond in the Eastern Mediterranean coast (Israel).

PubMed

Zohar, I; Bookman, R; Levin, N; de Stigter, H; Teutsch, N

2014-12-02

Pollution history of Pb and other trace metals was reconstructed for the first time for the Eastern Mediterranean, from a small urban winter pond (Dora, Netanya), located at the densely populated coastal plain of Israel. An integrated approach including geochemical, sedimentological, and historical analyses was employed to study sediments from the center of the pond. Profiles of metal concentrations (Pb, Zn, V, Ni, Cu, Cr, Co, Cd, and Hg) and Pb isotopic composition denote two main eras of pre- and post-19th century. The deeper sediment is characterized by low concentrations and relatively constant 206Pb/207Pb (around 1.20), similar to natural Pb sources, with slight indications of ancient anthropogenic activity. The upper sediment displays an upward increase in trace metal concentrations, with the highest enrichment factor for Pb (18.4). Lead fluxes and isotopic composition point to national/regional petrol-Pb emissions as the major contributor to Pb contamination, overwhelming other potential local and transboundary sources. Traffic-related metals are correlated with Pb, emphasizing the polluting inputs of traffic. The Hg profile, however, implies global pollution rather than local sources.

INEEL Subregional Conceptual Model Report Volume 3: Summary of Existing Knowledge of Natural and Anthropogenic Influences on the Release of Contaminants to the Subsurface Environment from Waste Source Terms at the INEEL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paul L. Wichlacz

2003-09-01

This source-term summary document is intended to describe the current understanding of contaminant source terms and the conceptual model for potential source-term release to the environment at the Idaho National Engineering and Environmental Laboratory (INEEL), as presented in published INEEL reports. The document presents a generalized conceptual model of the sources of contamination and describes the general categories of source terms, primary waste forms, and factors that affect the release of contaminants from the waste form into the vadose zone and Snake River Plain Aquifer. Where the information has previously been published and is readily available, summaries of the inventorymore » of contaminants are also included. Uncertainties that affect the estimation of the source term release are also discussed where they have been identified by the Source Term Technical Advisory Group. Areas in which additional information are needed (i.e., research needs) are also identified.« less

Source to point of use drinking water changes and knowledge, attitude and practices in Katsina State, Northern Nigeria

NASA Astrophysics Data System (ADS)

Onabolu, B.; Jimoh, O. D.; Igboro, S. B.; Sridhar, M. K. C.; Onyilo, G.; Gege, A.; Ilya, R.

In many Sub-Saharan countries such as Nigeria, inadequate access to safe drinking water is a serious problem with 37% in the region and 58% of rural Nigeria using unimproved sources. The global challenge to measuring household water quality as a determinant of safety is further compounded in Nigeria by the possibility of deterioration from source to point of use. This is associated with the use of decentralised water supply systems in rural areas which are not fully reticulated to the household taps, creating a need for an integrated water quality monitoring system. As an initial step towards establishing the system in the north west and north central zones of Nigeria, The Katsina State Rural Water and Sanitation Agency, responsible for ensuring access to safe water and adequate sanitation to about 6 million people carried out a three pronged study with the support of UNICEF Nigeria. Part 1 was an assessment of the legislative and policy framework, institutional arrangements and capacity for drinking water quality monitoring through desk top reviews and Key Informant Interviews (KII) to ascertain the institutional capacity requirements for developing the water quality monitoring system. Part II was a water quality study in 700 households of 23 communities in four local government areas. The objectives were to assess the safety of drinking water, compare the safety at source and household level and assess the possible contributory role of end users’ Knowledge Attitudes and Practices. These were achieved through water analysis, household water quality tracking, KII and questionnaires. Part III was the production of a visual documentary as an advocacy tool to increase awareness of the policy makers of the linkages between source management, treatment and end user water quality. The results indicate that except for pH, conductivity and manganese, the improved water sources were safe at source. However there was a deterioration in water quality between source and point of use in 18%, 12.5%, 27% and 50% of hand pump fitted boreholes, motorised boreholes, hand dug wells and streams respectively. Although no statistical correlation could be drawn between water management practices and water quality deterioration, the survey of the study households gave an indication of the possible contributory role of their knowledge, attitudes and practices to water contamination after provision. Some of the potential water related sources of contamination were poor source protection and location, use of unimproved water source and poor knowledge and practice of household water treatment methods, poor hand washing practices in terms of percentage that wash hands and use soap. Consequently 34 WASH departments have been created at the local government level towards establishment of a community based monitoring system and piloting has begun in Kaita local government area.

Contaminants in ventilated filling boxes

NASA Astrophysics Data System (ADS)

Bolster, D. T.; Linden, P. F.

While energy efficiency is important, the adoption of energy-efficient ventilation systems still requires the provision of acceptable indoor air quality. Many low-energy systems, such as displacement or natural ventilation, rely on temperature stratification within the interior environment, always extracting the warmest air from the top of the room. Understanding buoyancy-driven convection in a confined ventilated space is key to understanding the flow that develops with many of these modern low-energy ventilation schemes. In this work we study the transport of an initially uniformly distributed passive contaminant in a displacement-ventilated space. Representing a heat source as an ideal sourced of buoyancy, analytical and numerical models are developed that allow us to compare the average efficiency of contaminant removal between traditional mixing and modern low-energy systems. A set of small-scale analogue laboratory experiments was also conducted to further validate our analytical and numerical solutions.We find that on average traditional and low-energy ventilation methods are similar with regard to pollutant flushing efficiency. This is because the concentration being extracted from the system at any given time is approximately the same for both systems. However, very different vertical concentration gradients exist. For the low-energy system, a peak in contaminant concentration occurs at the temperature interface that is established within the space. This interface is typically designed to sit at some intermediate height in the space. Since this peak does not coincide with the extraction point, displacement ventilation does not offer the same benefits for pollutant flushing as it does for buoyancy removal.

Modelling of faecal indicator bacteria (FIB) in the Red River basin (Vietnam).

PubMed

Nguyen, Huong Thi Mai; Billen, Gilles; Garnier, Josette; Rochelle-Newall, Emma; Ribolzi, Olivier; Servais, Pierre; Le, Quynh Thi Phuong

2016-09-01

Many studies have been published on the use of models to assess water quality through faecal contamination levels. However, the vast majority of this work has been conducted in developed countries and similar studies from developing countries in tropical regions are lacking. Here, we used the Seneque/Riverstrahler model to investigate the dynamics and seasonal distribution of total coliforms (TC), an indicator of faecal contamination, in the Red River (Northern Vietnam) and its upstream tributaries. The results of the model showed that, in general, the overall correlations between the simulated and observed values of TC follow a 1:1 relationship at all examined stations. They also showed that TC numbers were affected by both land use in terms of human and livestock populations and by hydrology (river discharge). We also developed a possible scenario based on the predicted changes in future demographics and land use in the Red River system for the 2050 horizon. Interestingly, the results showed only a limited increase of TC numbers compared with the present situation at all stations, especially in the upstream Vu Quang station and in the urban Ha Noi station. This is probably due to the dominance of diffuse sources of contamination relative to point sources. The model is to our knowledge one of the first mechanistic models able to simulate spatial and seasonal variations of microbial contamination (TC numbers) in the whole drainage network of a large regional river basin covering both urban and rural areas of a developing country.

Origin and spatial-temporal distribution of faecal bacteria in a bay of Lake Geneva, Switzerland.

PubMed

Poté, John; Goldscheider, Nico; Haller, Laurence; Zopfi, Jakob; Khajehnouri, Fereidoun; Wildi, Walter

2009-07-01

The origin and distribution of microbial contamination in Lake Geneva's most polluted bay were assessed using faecal indicator bacteria (FIB). The lake is used as drinking water, for recreation and fishing. During 1 year, water samples were taken at 23 points in the bay and three contamination sources: a wastewater treatment plant (WWTP), a river and a storm water outlet. Analyses included Escherichia coli, enterococci (ENT), total coliforms (TC), and heterotrophic plate counts (HPC). E. coli input flux rates from the WWTP can reach 2.5 x 10(10) CFU/s; those from the river are one to three orders of magnitude lower. Different pathogenic Salmonella serotypes were identified in water from these sources. FIB levels in the bay are highly variable. Results demonstrate that (1) the WWTP outlet at 30 m depth impacts near-surface water quality during holomixis in winter; (2) when the lake is stratified, the effluent water is generally trapped below the thermocline; (3) during major floods, upwelling across the thermocline may occur; (4) the river permanently contributes to contamination, mainly near the river mouth and during floods, when the storm water outlet contributes additionally; (5) the lowest FIB levels in the near-surface water occur during low-flow periods in the bathing season.

Assessment of biotic response to heavy metal contamination in Avicennia marina mangrove ecosystems in Sydney Estuary, Australia.

PubMed

Nath, Bibhash; Chaudhuri, Punarbasu; Birch, Gavin

2014-09-01

Mangrove forests act as a natural filter of land-derived wastewaters along industrialized tropical and sub-tropical coastlines and assist in maintaining a healthy living condition for marine ecosystems. Currently, these intertidal communities are under serious threat from heavy metal contamination induced by human activity associated with rapid urbanization and industrialization. Studies on the biotic responses of these plants to heavy metal contamination are of great significance in estuary management and maintaining coastal ecosystem health. The main objective of the present investigation was to assess the biotic response in Avicennia marina ecosystems to heavy metal contamination through the determination of metal concentrations in leaves, fine nutritive roots and underlying sediments collected in fifteen locations across Sydney Estuary (Australia). Metal concentrations (especially Cu, Pb and Zn) in the underlying sediments of A. marina were enriched to a level (based on Interim Sediment Quality Guidelines) at which adverse biological effects to flora could occasionally occur. Metals accumulated in fine nutritive roots greater than underlying sediments, however, only minor translocation of these metals to A. marina leaves was observed (mean translocation factors, TFs, for all elements <0.13, except for Mn). Translocation factors of essential elements (i.e., common plant micro-nutrients, Cu, Ni, Mn and Zn) were greater than non-essential elements (As, Cd, Co, Cr and Pb), suggesting that A. marina mangroves of this estuary selectively excluded non-essential elements, while regulating essential elements and limiting toxicity to plants. This study supports the notion that A. marina mangroves act as a phytostabilizer in this highly modified estuary thereby protecting the aquatic ecosystem from point or non-point sources of heavy metal contamination. Copyright © 2014 Elsevier Inc. All rights reserved.

Water quality and health in northern Canada: stored drinking water and acute gastrointestinal illness in Labrador Inuit.

PubMed

Wright, Carlee J; Sargeant, Jan M; Edge, Victoria L; Ford, James D; Farahbakhsh, Khosrow; Shiwak, Inez; Flowers, Charlie; Harper, Sherilee L

2017-07-12

One of the highest self-reported incidence rates of acute gastrointestinal illness (AGI) in the global peer-reviewed literature occurs in Inuit communities in the Canadian Arctic. This high incidence of illness could be due, in part, to the consumption of contaminated water, as many northern communities face challenges related to the quality of municipal drinking water. Furthermore, many Inuit store drinking water in containers in the home, which could increase the risk of contamination between source and point-of-use (i.e., water recontamination during storage). To examine this risk, this research characterized drinking water collection and storage practices, identified potential risk factors for water contamination between source and point-of-use, and examined possible associations between drinking water contamination and self-reported AGI in the Inuit community of Rigolet, Canada. The study included a cross-sectional census survey that captured data on types of drinking water used, household practices related to drinking water (e.g., how it was collected and stored), physical characteristics of water storage containers, and self-reported AGI. Additionally, water samples were collected from all identified drinking water containers in homes and analyzed for presence of Escherichia coli and total coliforms. Despite municipally treated tap water being available in all homes, 77.6% of households had alternative sources of drinking water stored in containers, and of these containers, 25.2% tested positive for total coliforms. The use of transfer devices and water dippers (i.e., smaller bowls or measuring cups) for the collection and retrieval of water from containers were both significantly associated with increased odds of total coliform presence in stored water (OR transfer device  = 3.4, 95% CI 1.2-11.7; OR dipper  = 13.4, 95% CI 3.8-47.1). Twenty-eight-day period prevalence of self-reported AGI during the month before the survey was 17.2% (95% CI 13.0-22.5), which yielded an annual incidence rate of 2.4 cases per person per year (95% CI 1.8-3.1); no water-related risk factors were significantly associated with AGI. Considering the high prevalence of, and risk factors associated with, indicator bacteria in drinking water stored in containers, potential exposure to waterborne pathogens may be minimized through interventions at the household level.

An In-Port Feeding System for Shipboard Personnel. Volume 4. Recommended Quality Control Requirements for a Central Food Service System

DTIC Science & Technology

1981-10-01

NUMBER(e) Ronald Josephson and Bonnie Sattler 9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PRGRAM ELEMENT. PROJECT. TASK San Diego State University... substances ; (2) determining sources and specific points of contamination, survival and growth of pathogens during food service operations; and (3...Control in Atlanta, has recommended (1981) the HACCP system as the best available insurance policy for prevention of foodborne illness in foodservice

Association of land use and beach closure in the United ...

EPA Pesticide Factsheets

Swimming in natural waters (e.g., oceans, lakes, rivers) is one of most popular recreational activities in the United States. However, exposure to pathogens (e.g., Salmonella spp., Shigella spp., Cryptosporidium, Giardia, adenovirus, norovirus) in recreational waters can lead to a variety of adverse health outcomes. To protect public health and reduce the number of outbreaks associated with recreational waters, the BEACH Act was passed in 2000, which required beach regulators to develop a formal plan to assess beach water quality and to notify the public if recreational waters are unsafe. High levels of microorganisms in water often follow extreme weather events. Besides extreme weather events, the proximity of certain land uses to beaches may also have great influence on beach water quality. Microbial contaminants that lead to beach closures and human illness come mainly from land, either from discrete point sources or from diffuse non-point sources. It is expected that land use will have considerable influence on beach microbial water quality. However, to date, studies on impacts of land use on beach microbial contamination are rare, and few researchers are aware of the relationship between land use and beach closures.In this study, we analyzed beach closure data obtained from 2004 to 2013 for more than 500 beaches in the United States, and examined their associations with land use around beaches in 2006 and 2011. The results show that the number of beach clos

The importance of policy in emissions inventory accuracy--a lesson from British Columbia, Canada.

PubMed

Krzyzanowski, Judi

2009-04-01

Actual atmospheric emissions in northeast British Columbia, Canada, are much higher than reported emissions. The addition of upstream oil and gas sector sources not included in the year-2000 emissions inventory of Criteria Air Contaminants (CACs) increases annual totals of nitrogen oxides, sulfur oxides, and volatile organic compound emissions by 115.1, 89.9, and 109.5%, respectively. These emissions arise from numerous small and unregulated point sources (N = 10,129). CAC summaries are given by source type and source sector. An analysis of uncertainty and reporting policy suggests that inventory omissions are not limited to the study area and that Canadian pollutant emissions are systematically underestimated. The omissions suggest that major changes in reporting procedures are needed in Canada if true estimates of annual pollutant emissions are to be documented.

Delineating Landfill Leachate Discharge To An Arsenic Contaminated Waterway

EPA Science Inventory

Discharge of contaminated ground water may serve as a primary and on-going source of contamination to surface water. A field investigation was conducted at a Superfund site in Massachusetts, USA to define the locus of contaminant flux and support source identification for arseni...

Spacecraft contamination issues from LDEF: Issues for design

NASA Technical Reports Server (NTRS)

Pippin, Gary; Crutcher, Russ

1993-01-01

Many contamination sources have been identified on the Long Duration Exposure Facility (LDEF). Effects of contamination from these sources are being quantified and have been reported on in several papers. For a designer, the essential question is how much contamination from all sources can be tolerated without causing a given spacecraft system to degrade below a critical performance level, or fail altogether. Even a rudimentary knowledge of the mechanisms by which molecular and particulate contamination can occur will allow simple design options to be chosen to circumvent potential contamination problems and reduce contamination levels. Because of the varied nature and condition of hardware used on LDEF experiments, examples of many types of contamination were seen and these provide a useful guide to expected performance of many types of materials in space environments.

Tracking sources of Staphylococcus aureus hand contamination in food handlers by spa typing.

PubMed

Ho, Jeffery; Boost, Maureen V; O'Donoghue, Margaret M

2015-07-01

We aimed to identify the source of Staphylococcus aureus contaminating hands of food handlers. Nasal samples and direct fingertip imprints were collected on 2 occasions from food handlers and characterized to determine likely sources of hand contamination. Most hand contamination was attributable to nasal isolates of persistently colonized coworkers who had presumably contaminated the environment. Regular handwashing should be supplemented by effective environmental disinfection. Copyright © 2015 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

Development of a microbial contamination susceptibility model for private domestic groundwater sources

NASA Astrophysics Data System (ADS)

Hynds, Paul D.; Misstear, Bruce D.; Gill, Laurence W.

2012-12-01

Groundwater quality analyses were carried out on samples from 262 private sources in the Republic of Ireland during the period from April 2008 to November 2010, with microbial quality assessed by thermotolerant coliform (TTC) presence. Assessment of potential microbial contamination risk factors was undertaken at all sources, and local meteorological data were also acquired. Overall, 28.9% of wells tested positive for TTC, with risk analysis indicating that source type (i.e., borehole or hand-dug well), local bedrock type, local subsoil type, groundwater vulnerability, septic tank setback distance, and 48 h antecedent precipitation were all significantly associated with TTC presence (p < 0.05). A number of source-specific design parameters were also significantly associated with bacterial presence. Hierarchical logistic regression with stepwise parameter entry was used to develop a private well susceptibility model, with the final model exhibiting a mean predictive accuracy of >80% (TTC present or absent) when compared to an independent validation data set. Model hierarchies of primary significance are source design (20%), septic tank location (11%), hydrogeological setting (10%), and antecedent 120 h precipitation (2%). Sensitivity analysis shows that the probability of contamination is highly sensitive to septic tank setback distance, with probability increasing linearly with decreases in setback distance. Likewise, contamination probability was shown to increase with increasing antecedent precipitation. Results show that while groundwater vulnerability category is a useful indicator of aquifer susceptibility to contamination, its suitability with regard to source contamination is less clear. The final model illustrates that both localized (well-specific) and generalized (aquifer-specific) contamination mechanisms are involved in contamination events, with localized bypass mechanisms dominant. The susceptibility model developed here could be employed in the appropriate location, design, construction, and operation of private groundwater wells, thereby decreasing the contamination risk, and hence health risk, associated with these sources.

Employing ASHRAE Standard 62-1989 in urban building environments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meckler, M.

1991-01-01

Indoor air quality (IAQ) is a result of a complex relationship between the contamination sources in a building, the ventilation rate, and the dilution of the indoor air contaminant concentrations with outdoor air. This complex relationship is further complicated by outdoor sources used for dilution air and pollution sinks in a building which may modify or remove contaminants. This paper reports that the factors influencing IAQ in a building are: emissions from indoor contamination sources, dilution rate of outdoor ventilation air, quality of the outdoor dilution air, and systems and materials in a building that change the concentrations of contaminants.more » Emissions from contaminant sources in a building are the primary determinant of IAQ. They include building materials, consumer products, cleaners, furnishings, combustion appliances and processes, biological growth from standing water and damp surfaces and building occupants. These factors combined with the emissions from indoor air contamination sources such as synthetic building materials, modern office equipment, and cleaning and biological agents are believed to increase the levels of indoor air contamination. The physiological reactions to these contaminants, coupled with the psychosocial stresses of the modern office environment, and the wide range of human susceptibility to indoor air contaminants led to the classification of acute building sicknesses: sick building syndrome (SBS), building-related illness (BRI), and multiple chemical sensitivity (MCS).« less

Polychlorinated Biphenyl (PCB) Bioaccumulation in Fish: A Look at Michigan's Upper Peninsula

NASA Astrophysics Data System (ADS)

Sokol, E. C.; Urban, N. R.; Perlinger, J. A.; Khan, T.; Friedman, C. L.

2014-12-01

Fish consumption is an important economic, social and cultural component of Michigan's UpperPeninsula, where safe fish consumption is threatened due to polychlorinated biphenyl (PCB)contamination. Despite its predominantly rural nature, the Upper Peninsula has a history of industrialPCB use. PCB congener concentrations in fish vary 50-fold in Upper Peninsula lakes. Several factors maycontribute to this high variability including local point sources, unique watershed and lakecharacteristics, and food web structure. It was hypothesized that the variability in congener distributionscould be used to identify factors controlling concentrations in fish, and then to use those factors topredict PCB contamination in fish from lakes that had not been monitored. Watershed and lakecharacteristics were acquired from several databases for 16 lakes sampled in the State's fishcontaminant survey. Species congener distributions were compared using Principal Component Analysis(PCA) to distinguish between lakes with local vs. regional, atmospheric sources; six lakes were predictedto have local sources and half of those have confirmed local PCB use. For lakes without local PCBsources, PCA indicated that lake size was the primary factor influencing PCB concentrations. The EPA'sbioaccumulation model, BASS, was used to predict PCB contamination in lakes without local sources as afunction of food web characteristics. The model was used to evaluate the hypothesis that deep,oligotrophic lakes have longer food webs and higher PCB concentrations in top predator fish. Based onthese findings, we will develop a mechanistic watershed-lake model to predict PCB concentrations infish as a function of atmospheric PCB concentrations, lake size, and trophic state. Future atmosphericconcentrations, predicted by modeling potential primary and secondary emission scenarios, will be usedto predict the time horizon for safe fish consumption.

Water contamination with heavy metals and trace elements from Kilembe copper mine and tailing sites in Western Uganda; implications for domestic water quality.

PubMed

Abraham, Mwesigye R; Susan, Tumwebaze B

2017-02-01

The mining and processing of copper in Kilembe, Western Uganda, from 1956 to 1982 left over 15 Mt of cupriferous and cobaltiferous pyrite dumped within a mountain river valley, in addition to mine water which is pumped to the land surface. This study was conducted to assess the sources and concentrations of heavy metals and trace elements in Kilembe mine catchment water. Multi-element analysis of trace elements from point sources and sinks was conducted which included mine tailings, mine water, mine leachate, Nyamwamba River water, public water sources and domestic water samples using ICP-MS. The study found that mean concentrations (mg kg -1 ) of Co (112), Cu (3320), Ni (131), As (8.6) in mine tailings were significantly higher than world average crust and were being eroded and discharged into water bodies within the catchment. Underground mine water and leachate contained higher mean concentrations (μg L -1 ) of Cu (9470), Co (3430) and Ni (590) compared with background concentrations (μg L -1 ) in un contaminated water of 1.9, 0.21 and 0.67 for Cu, Co and Ni respectively. Over 25% of household water samples exceeded UK drinking water thresholds for Al of 200 μg L -1 , Co exceeded Winsconsin (USA drinking) water thresholds of 40 μg L -1 in 40% of samples while Fe in 42% of samples exceeded UK thresholds of 200 μg L -1 . The study however found that besides mining activities, natural processes of geological weathering also contributed to Al, Fe, and Mn water contamination in a number of public water sources. Copyright © 2016 Elsevier Ltd. All rights reserved.

Micro-x-ray fluorescence, micro-x-ray absorption spectroscopy, and micro-x-ray diffraction investigation of lead speciation after the addition of different phosphorus amendments to a smelter-contaminated soil.

PubMed

Baker, Lucas R; Pierzynski, Gary M; Hettiarachchi, Ganga M; Scheckel, Kirk G; Newville, Matthew

2014-03-01

The stabilization of Pb on additions of P to contaminated soils and mine spoil materials has been well documented. It is clear from the literature that different P sources result in different efficacies of Pb stabilization in the same contaminated material. We hypothesized that the differences in the efficacy of Pb stabilization in contaminated soils on fluid or granular P amendment addition is due to different P reaction processes in and around fertilizer granules and fluid droplets. We used a combination of several synchrotron-based techniques (i.e., spatially resolved micro-X-ray fluorescence, micro-X-ray absorption near-edge structure spectroscopy, and micro-X-ray diffraction) to speciate Pb at two incubation times in a smelter-contaminated soil on addition of several fluid and granular P amendments. The results indicated that the Pb phosphate mineral plumbogummite was an intermediate phase of pyromorphite formation. Additionally, all fluid and granular P sources were able to induce Pb phosphate formation, but fluid phosphoric acid (PA) was the most effective with time and distance from the treatment. Granular phosphate rock and triple super phosphate (TSP) amendments reacted to generate Pb phosphate minerals, with TSP being more effective at greater distances from the point of application. As a result, PA and TSP were the most effective P amendments at inducing Pb phosphate formation, but caution needs to be exercised when adding large amounts of soluble P to the environment. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Time-integrated passive sampling as a complement to conventional point-in-time sampling for investigating drinking-water quality, McKenzie River Basin, Oregon, 2007 and 2010-11

USGS Publications Warehouse

McCarthy, Kathleen A.; Alvarez, David A.

2014-01-01

The Eugene Water & Electric Board (EWEB) supplies drinking water to approximately 200,000 people in Eugene, Oregon. The sole source of this water is the McKenzie River, which has consistently excellent water quality relative to established drinking-water standards. To ensure that this quality is maintained as land use in the source basin changes and water demands increase, EWEB has developed a proactive management strategy that includes a combination of conventional point-in-time discrete water sampling and time‑integrated passive sampling with a combination of chemical analyses and bioassays to explore water quality and identify where vulnerabilities may lie. In this report, we present the results from six passive‑sampling deployments at six sites in the basin, including the intake and outflow from the EWEB drinking‑water treatment plant (DWTP). This is the first known use of passive samplers to investigate both the source and finished water of a municipal DWTP. Results indicate that low concentrations of several polycyclic aromatic hydrocarbons and organohalogen compounds are consistently present in source waters, and that many of these compounds are also present in finished drinking water. The nature and patterns of compounds detected suggest that land-surface runoff and atmospheric deposition act as ongoing sources of polycyclic aromatic hydrocarbons, some currently used pesticides, and several legacy organochlorine pesticides. Comparison of results from point-in-time and time-integrated sampling indicate that these two methods are complementary and, when used together, provide a clearer understanding of contaminant sources than either method alone.

Quantification of contamination levels and particular risk of Salmonella spp. in pigs in slaughterhouses in Chiang Mai and Lamphun provinces, Thailand.

PubMed

Tadee, Pakpoom; Boonkhot, Phacharaporn; Patchanee, Prapas

2014-11-01

Salmonella spp. is one of the important foodborne pathogens, and the slaughtering process is recognized as a potential point of contamination and the spread of the pathogens. The three objectives of this study are first, to quantify the contamination levels of Salmonella spp. in pig skins and carcasses, second, to evaluate the outcomes from different pig supply sources and different practices at three critical steps (scalding, splitting, and washing) for Salmonella spp. contamination, and third, to assess risk of Salmonella spp. contamination in pork products after slaughtering level. The study was performed in three representative slaughterhouses in Chiang Mai and Lamphun provinces, Thailand. Investigation conducted from May 2013 through October 2013 found the overall prevalence and contamination levels mean to be 11.85% and 0.34 MPN/cm2, respectively. There was no statistically significant in Salmonella spp. prevalence and contamination levels detected with different patterns at the slaughterhouses which were supplied pigs from either co-operative or integrated farms. Factors found to reduce Salmonella spp. loads on carcasses included good practices, e.g., regular changing of water in the scalding tank after each batch and the use of chlorine in the washing step. Risk of Salmonella spp. contamination of pork products at the final stage of slaughtering was nearly 10%. Good practices and proper hygiene measures should be applied to minimize the risk of Salmonella spp. exposure in the slaughtering line, which can reduce the contamination pressure downstream at retail shops as well as for end consumers.

Levels and profiles of PCBs and OCPs in marine benthic species from the Belgian North Sea and the Western Scheldt Estuary.

PubMed

Voorspoels, Stefan; Covaci, Adrian; Maervoet, Johan; De Meester, Ingrid; Schepens, Paul

2004-09-01

Various benthic invertebrates (flying crab, common shrimp, and red starfish), small fish (sand goby), benthic flatfish (dab, plaice, and sole) and gadoids (bib and whiting) were collected in the Belgian North Sea and along the Scheldt Estuary, both representing areas impacted by various contaminants to different degrees. The levels of 25 polychlorinated biphenyls (PCBs) and 15 organochlorine pesticides (OCPs), which included penta- and hexachlorobenzene, alpha-, beta-, and gamma-hexachlorocyclohexane isomers, chlordanes, and DDT and metabolites, were determined. Sum of PCBs and OCPs in benthic invertebrates and goby ranged from 1.5 to 280 ng/g wet weight (ww) and from 0.27 to 23 ng/g ww, respectively. The fish livers revealed total PCB and OCP levels ranging from 20 to 3200 ng/g ww and from 6.0 to 410 ng/g ww, respectively. Levels of both contaminant groups were significantly higher in samples from the Scheldt Estuary compared to the Belgian North Sea. For most species a highly inverse correlation was found between the concentration of contaminants and the distance to Antwerp (r between 0.812 and 0.901, p < 0.05), pointing to a higher degree of exposure further upstream. PCB and OCP exposures are highly correlated (r between 0.836 and 1.000, p < 0.05), which suggests that the pollution can be classified as historical. However, because urban and industrial centres may still be emitting these compounds, more recent point and non-point sources cannot be ruled out. Copyright 2004 Elsevier Ltd.

Ground-Water Age and its Water-Management Implications, Cook Inlet Basin, Alaska

USGS Publications Warehouse

Glass, Roy L.

2002-01-01

The Cook Inlet Basin encompasses 39,325 square miles in south-central Alaska. Approximately 350,000 people, more than half of Alaska?s population, reside in the basin, mostly in the Anchorage area. However, rapid growth is occurring in the Matanuska?Susitna and Kenai Peninsula Boroughs to the north and south of Anchorage. Ground-water resources provide about one-third of the water used for domestic, commercial and industrial purposes in the Anchorage metropolitan area and are the sole sources of water for industries and residents outside Anchorage. In 1997, a study of the Cook Inlet Basin was begun as part of the U.S. Geological Survey?s National Water-Quality Assessment Program. Samples of ground water were collected from 35 existing wells in unconsolidated glacial and alluvial aquifers during 1999 to determine the regional quality of ground water beneath about 790 mi2 of developed land and to gain a better understanding of the natural and human factors that affect the water quality (Glass, 2001). Of the 35 wells sampled, 31 had water analyzed for atmospherically derived substances to determine the ground water?s travel time from its point of recharge to its point of use or discharge?also known as ground-water age. Ground water moves slowly from its point of recharge to its point of use or discharge. This water starts as rain and melting snow that soak into the ground as recharge. In the Matanuska?Susitna, Anchorage, and Kenai Peninsula areas, ground water generally moves from near the mountain fronts toward Cook Inlet or the major rivers. Much of the water pumped by domestic and public-supply wells may have traveled less than 10 miles, and the trip may have taken as short a time as a few days or as long as several decades. This ground water is vulnerable to contamination from the land surface, and many contaminants in the water would follow the same paths and have similar travel times from recharge areas to points of use as the chemical substances analyzed in this study. The effects of contamination may not be seen for several years after a contaminant is introduced into the ground-water system. Many contaminants could make the water unsuitable for drinking for many years, even in concentrations too low to detect without expensive chemical tests. The travel time of a chemically conservative substance depends primarily on the velocity of ground water through the aquifer, which in turn depends on the hydrologic characteristics of the aquifer system.

Assessment of hydrogeologic terrains, well-construction characteristics, groundwater hydraulics, and water-quality and microbial data for determination of surface-water-influenced groundwater supplies in West Virginia

USGS Publications Warehouse

Kozar, Mark D.; Paybins, Katherine S.

2016-08-30

Groundwater public-supply systems in areas of high intrinsic susceptibility and with a large number of potential contaminant sources within the recharge or source-water-protection area of individual wells or well fields are potentially vulnerable to contamination and probably warrant further evaluation as potential SWIGS. However, measures can be taken to educate the local population and initiate safety protocols and protective strategies to appropriately manage contaminant sources to prevent release of contaminants to the aquifer, therefore, reducing vulnerability of these systems to contamination. However, each public groundwater supply source needs to be assessed on an individual basis. Data presented in this report can be used to categorize and prioritize wells and springs that have a high potential for intrinsic susceptibility or vulnerability to contamination.

Bioinjection Performance Review for the Building 100 Area and 4.5 Acre Site at the Pinellas County, Florida, Site

DOE Office of Scientific and Technical Information (OSTI.GOV)

Survochak, Scott; Daniel, Joe

This document provides a summary of a review of the performance of bioinjection activities at the Building 100 Area and the 4.5 Acre Site at the Pinellas County, Florida, Site since 2010, determines how best to optimize future injection events, and identifies the approach for the bioinjection event in 2016 at (1) the 4.5 Acre Site and (2) the Essentra property at the Building 100 Area. Because this document describes the next bioinjection event at the 4.5 Acre Site, it also serves as an addendum to the Interim Remedial Action Plan for Emulsified Edible Oil Injection at the 4.5 Acremore » Site (DOE 2013). In addition, this document revises the injection layout and injection intervals for the Essentra property that were originally described in the Interim Corrective Measure Work Plan for Source and Plume Treatment at the Building 100 Area (DOE 2014), and is a de facto update of that document. Bioinjection consists of injection of emulsified vegetable oil (EVO) and the microorganism Dehalococcoides mccartyi (DHM; formerly known as Dehalococcoides ethenogenes) into the subsurface to enhance biodegradation of trichloroethene (TCE), dichloroethene (DCE), and vinyl chloride (VC). VC is the only contaminant that exceeds its maximum contaminant level (10 micrograms per liter onsite and 1 microgram per liter onsite) on the 4.5 Acre Site and the Essentra property. Bioinjection was conducted at the 4.5 Acre Site in 2010 and 2013. Approximately 49,900 gallons of EVO and DHM were injected at 95 injection points in February 2010, and approximately 22,900 gallons of EVO and DHM were injected at 46 injection points in July 2013. The injection locations are shown on Figure 1. The goal of bioinjection at the 4.5 Acre Site is to decrease contaminant concentrations to maximum contaminant levels along the west and southwest property boundaries (to meet risk–based corrective action requirements) and to minimize the extent of the contaminant plume in the interior of the site. Bioinjection was conducted at the Building 100 Area in 3 phases from October 2014 through November 2015 (Figures 2–4). Approximately 32,850 gallons of EVO and DHM were injected using 62 temporary injection points in the onsite plumes in October and November 2014, 16,500 gallons were injected using 33 temporary injection points in the offsite plumes in February 2015, and 51,000 gallons were injected beneath the building using 8 horizontal wells in November 2015. The goal of bioinjection at the Building 100 Area is to enhance contaminant biodegradation to stabilize or shrink the contaminant plumes.« less

Using Sediment Records to Reconstruct Historical Inputs Combustion-Derived Contaminants to Urban Airsheds/Watersheds: A Case Study From the Puget Sound

NASA Astrophysics Data System (ADS)

Louchouarn, P. P.; Kuo, L.; Brandenberger, J.; Marcantonio, F.; Wade, T. L.; Crecelius, E.; Gobeil, C.

2008-12-01

Urban centers are major sources of combustion-derived particulate matter (e.g. black carbon (BC), polycyclic aromatic hydrocarbons (PAH), anhydrosugars) and volatile organic compounds to the atmosphere. Evidence is mounting that atmospheric emissions from combustion sources remain major contributors to air pollution of urban systems. For example, recent historical reconstructions of depositional fluxes for pyrogenic PAHs close to urban systems have shown an unanticipated reversal in the trends of decreasing emissions initiated during the mid-20th Century. Here we compare a series of historical reconstructions of combustion emission in urban and rural airsheds over the last century using sedimentary records. A complex suite of combustion proxies (BC, PAHs, anhydrosugars, stable lead concentrations and isotope signatures) assisted in elucidating major changes in the type of atmospheric aerosols originating from specific processes (i.e. biomass burning vs. fossil fuel combustion) or fuel sources (wood vs. coal vs. oil). In all studied locations, coal continues to be a major source of combustion-derived aerosols since the early 20th Century. Recently, however, oil and biomass combustion have become substantial additional sources of atmospheric contamination. In the Puget Sound basin, along the Pacific Northwest region of the U.S., rural locations not impacted by direct point sources of contamination have helped assess the influence of catalytic converters on concentrations of oil-derived PAH and lead inputs since the early 1970s. Although atmospheric deposition of lead has continued to drop since the introduction of catalytic converters and ban on leaded gasoline, PAH inputs have "rebounded" in the last decade. A similar steady and recent rise in PAH accumulations in urban systems has been ascribed to continued urban sprawl and increasing vehicular traffic. In the U.S., automotive emissions, whether from gasoline or diesel combustion, are becoming a major source of combustion-derived PM and BC to the atmosphere and have started to replace coal as the major source in some surficial reservoirs. This increased urban influence of gasoline and diesel combustion on BC emissions was also observed in Europe both from model estimates as well as from measured fluxes in recent lake sediments.

Screening for Groundwater Contaminants Discharging to Urban Streams

NASA Astrophysics Data System (ADS)

Roy, J. W.; Bickerton, G.; Voralek, J.

2009-05-01

Groundwater contaminated with urban pollutants can adversely affect freshwater aquatic ecosystems where it discharges to streams, lakes or wetlands. Generally such occurrences have been revealed following the discovery of contaminated groundwater plumes at a particular site or from wells in the area. Thus, this contaminant pathway tends to be dealt with on a site-specific and aquifer-focused basis. In contrast, surface water contaminant monitoring typically relies on bulk water concentrations from one or a small set of locations, thus ignoring the spatial variation in contaminant loading, potential losses to sediment or the atmosphere, and the full range of benthic components of the aquatic ecosystem. There are few studies outlining the extent of this contamination from the perspective of the surface water body's deeper benthic community, which might be expected to experience the greatest contaminant concentrations, on more than a local-scale. In this study, we report on an approach to stream-reach-screening for urban contaminants in discharging groundwater, with the focus on detection rather than accurate quantification. The methodology consists of a drive-point technique for sampling groundwater from below the stream bed (e.g. typically 50 cm) along a chosen reach at intervals of about 10 m. Groundwater samples were then analyzed for a wide range of common urban contaminants and general chemistry. This screening method was performed in three urban settings in Canada with known groundwater contamination, covering sections of about 140 to >500 m. The known contaminant plumes at each site were detected and roughly delineated. In addition, potential areas of previously-unknown groundwater contamination were also identified at each site. Contaminants included BTEX and other petroleum hydrocarbons, various chlorinated solvent compounds, nitrate, 1,4-dioxane, MTBE and elevated chloride (likely indicating road salt). These preliminary findings suggest that this approach may be useful for quickly assessing the cumulative threat to aquatic ecosystems of potentially multiple groundwater contaminant sources discharging to surface water bodies in urban settings.

Development of a chemical source apportionment decision support framework for lake catchment management.

PubMed

Comber, Sean D W; Smith, Russell; Daldorph, Peter; Gardner, Michael J; Constantino, Carlos; Ellor, Brian

2018-05-01

Increasing pressures on natural resources has led to the adoption of water quality standards to protect ecological and human health. Lakes and reservoirs are particularly vulnerable to pressure on water quality owing to long residence times compared with rivers. This has raised the question of how to determine and to quantify the sources of priority chemicals (e.g. nutrients, persistent organic pollutants and metals) so that suitable measures can be taken to address failures to comply with regulatory standards. Contaminants enter lakes waters from a range of diffuse and point sources. Decision support tools and models are essential to assess the relative magnitudes of these sources and to estimate the impacts of any programmes of measures. This paper describes the development and testing of the Source Apportionment Geographical Information System (SAGIS) for future management of 763 lakes in England and Wales. The model uses readily available national data sets to estimate contributions of a number of key chemicals including nutrients (nitrogen and phosphorus), metals (copper, zinc, cadmium, lead, mercury and nickel) and organic chemicals (Polynuclear Aromatic Hydrocarbons) from multiple sector sources. Lake-specific sources are included (groundbait from angling and bird faeces) and hydrology associated with pumped inputs and abstraction. Validation data confirms the efficacy of the model to successfully predicted seasonal patterns of all types of contaminant concentrations under a number of hydrological scenarios. Such a tool has not been available on a national scale previously for such a wide range of chemicals and is currently being used to assist with future river basin planning. Copyright © 2017 Elsevier B.V. All rights reserved.

Development of integrated protocols to track the deposition and impacts of metal contaminants in tidal riverine environments

NASA Astrophysics Data System (ADS)

Roe, Helen M.; Patterson, R. Timothy; Nasser, Nawaf; Edwards, Robin J.; Graham, Conor

2016-04-01

Tidally-influenced rivers are particularly vulnerable to the effects of metal contamination, yet are amongst the most complex fluvial environments in terms of their sediment deposition and transport patterns. We present the results of an interdisciplinary study that aims to elucidate the fluxes and deposition of metal contaminants in a tidally-influenced river system in Northern Ireland, with a view to developing protocols that will have wide applicability for the monitoring and assessment of metal contaminants in similar environments in other regions. We employ a novel methodology that combines ICPMS analysis of sediments, ITRAX-based core analysis and the examination a important group of shelled protozoans (foraminifera), which occur widely in tidal riverine environments, and which are highly sensitive to metal contamination. The responses shown by the group vary between species and with different levels of contaminant exposure. Some species, for example, show increased relative abundances in proximity to discharge sources, whilst others develop chamber deformities. Application of our integrated multiproxy approach to the analysis of surface sediment samples and cores provides a framework for assessing both the spatial and temporal patterns of metal deposition and the impact of contaminants on the biota. Modern sediment samples (n=90) were collected at varying distances from a point contamination source (a former industrial site) in different morpho-sedimentary settings. The impact of 25 measured variables on the modern foraminiferal faunas was considered, including 20 metals, pH, conductivity, elevation and particle size. Channel sediments in close proximity to the contamination source and with the highest levels of Fe, Cu, Zn, Mg and As, yielded the sparsest foraminiferal faunas (Shannon Diversity Index values 0-1.5), whilst the highest prevalence of foraminiferids showing chamber deformities were observed in channel edge and levée bank sites. Kernal density plots showing metal loading and foraminiferal concentrations across the site aided in determining spatial trends. The sediment core data revealed that deformed foraminiferal specimens can extend >15 cm below the contemporary floodplain surface to horizons that pre-date the historical onset of the contamination, suggesting vertical mobilisation of sediment and/or infaunal migration. Etching of the foraminiferal tests in association with reduced pH conditions was also observed for some species. Biometric analysis of tests using SEM imagery further aided in the identification of deformities and the delimitation of graded responses to contaminants. The results of this study of core and surficial samples indicate that the adoption of integrated methodologies that combine established geochemical analysis techniques (e.g. ICPMS analysis) with the observed ecophenotypic response of key indicator microfossil groups (e.g. foraminifera) can provide invaluable data on habitat responses to environmental contamination. Such long-term habitat evaluation data is invaluable to policy makers and planners when prioritising management and remediation efforts.

NAWQA, National Water-Quality Assessment Program; Allegheny-Monongahela River Basin

USGS Publications Warehouse

McAuley, Steven D.; Brown, Juliane B.; Sams, James I.

1997-01-01

Surface-water and ground-water quality and aquatic life can be significantly affected by the following principal issues identified in the Allegheny-Monongahela River Basin:Contaminants common to surface and under-ground coal mine discharge such as acidity, iron, aluminum, manganese, and sulfate.Volatile organic compounds (VOC’s), pesti-cides, and nutrients from increased urbanization.Runoff and loading of nutrients and pesticides to streams from nonpoint and point sources such as agricultural land uses.Radon in ground water.

Development and application of a green fluorescent protein (GFP) expressing E. coli O103 surrogate for tracking contamination through grinding and identifying persistent points of contamination

USDA-ARS?s Scientific Manuscript database

Objective: To 1.) develop and validate an easily trackable E. coli O157:H7/non-O157 STEC surrogate that can be detected to the same level of sensitivity as E. coli O157:H7; and 2.) apply the trackable surrogate to model contamination passage through grinding and identify points where contamination ...

Sources and Practices Contributing to Soil Contamination

Treesearch

A.S. Knox; A.P. Gamerdinger; D.C. Adriano; R.K. Kolka; D.I. Kaplan

1999-01-01

The term soil contamination can have different connotations because anthropogehic sources of contaminants have affected virtually every natural ecosystem in the world; a commonly held view is that contamination occurs when the soil composition deiiates from the normal composition (Adriano et al., 1997). Other specialists have defined soil pollution as the presence of...

Salmonellosis outbreaks in the United States due to fresh produce: sources and potential intervention measures.

PubMed

Hanning, Irene B; Nutt, J D; Ricke, Steven C

2009-01-01

Foodborne Salmonella spp. is a leading cause of foodborne illness in the United States each year. Traditionally, most cases of salmonellosis were thought to originate from meat and poultry products. However, an increasing number of salmonellosis outbreaks are occurring as a result of contaminated produce. Several produce items specifically have been identified in outbreaks, and the ability of Salmonella to attach or internalize into vegetables and fruits may be factors that make these produce items more likely to be sources of Salmonella. In addition, environmental factors including contaminated water sources used to irrigate and wash produce crops have been implicated in a large number of outbreaks. Salmonella is carried by both domesticated and wild animals and can contaminate freshwater by direct or indirect contact. In some cases, direct contact of produce or seeds with contaminated manure or animal wastes can lead to contaminated crops. This review examines outbreaks of Salmonella due to contaminated produce, the potential sources of Salmonella, and possible control measures to prevent contamination of produce.

Sources of Salmonella on broiler carcasses during transportation and processing: modes of contamination and methods of control.

PubMed

Corry, Janet E L; Allen, V M; Hudson, W R; Breslin, M F; Davies, R H

2002-01-01

The prevalence and types of salmonella in broiler chickens during transportation and during slaughter and dressing were studied. This was part of a comprehensive investigation of salmonellas in two UK poultry companies, which aimed to find the origins and mechanisms of salmonella contamination. Salmonellas were isolated using cultural methods. Serovars of Salmonella detected during rearing were usually also found in a small proportion of birds on the day of slaughter and on the carcasses at various points during processing. There was little evidence of salmonellas spreading to large numbers of carcasses during processing. Many serovars found in the feedmills or hatcheries were also detected in the birds during rearing and/or slaughter. Transport crates were contaminated with salmonellas after washing and disinfection. Prevalence of salmonellas fell in the two companies during this survey. A small number of serovars predominated in the processing plants of each company. These serovars originated from the feed mills. Reasons for transport crate contamination were: (1) inadequate cleaning, resulting in residual faecal soiling; (2) disinfectant concentration and temperature of disinfectant too low; (3) contaminated recycled flume water used to soak the crates. Efforts to control salmonella infection in broilers need to concentrate on crate cleaning and disinfection and hygiene in the feed mills.

A GIS-aided assessment of the health hazards of cadmium in farm soils in central Taiwan.

PubMed

Chiang, Po-Huang; Chan, Ta-Chien; Hsieh, Dennis P H

2011-09-01

A geostatistical method was developed to examine the correlation, or lack of it, between the levels of cadmium (Cd) detected in farm soils and those detected in the human specimens collected from residents around the contaminated areas in Changhua County where cadmium contamination of staple rice has been documented. We used the Taiwan EPA environment data in 2002 and human data which were generated by the National Health Research Institutes during 2003-2005. Kriging interpolation methods were used to determine soil Cd concentrations. A Zonal statistical function was performed to assess the individual exposure. Soil Cd levels and tissue Cd levels in residents were analyzed for contamination hotspots and other areas to determine correlation between the two variables. Three Cd contamination hotspots were identified, in which no correlation was found between soil Cd levels and tissue Cd levels in residents. Our results demonstrate how GIS spatial modeling technique can be used to estimate distribution of pollutants in an area using a limited number of data points. Results indicated no association between the soil contamination and the exposure of residents to Cd, suggesting that both the soils and the residents are receptors of Cd as a pollutant from as yet unidentified sources.

Chemical contaminants in the Wadden Sea: Sources, transport, fate and effects

NASA Astrophysics Data System (ADS)

Laane, R. W. P. M.; Vethaak, A. D.; Gandrass, J.; Vorkamp, K.; Köhler, A.; Larsen, M. M.; Strand, J.

2013-09-01

The Wadden Sea receives contaminants from various sources and via various transport routes. The contaminants described in this overview are various metals (Cd, Cu, Hg, Pb and Zn) and various organic contaminants (polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs) and lindane (hexachlorocyclohexane, γ-HCH)). In addition, information is presented about other and emerging contaminants such as antifouling biocides (e.g. TBT and Irgarol), brominated flame retardants (BFRs), poly- and perfluorinated compounds (PFCs) and pharmaceutical and personal care products (PPCPs). Special attention is given to biogeochemical processes that contribute to the mobilization of contaminants in the surface sediments of the Wadden Sea. Finally, the effects on organisms of contaminants are reviewed and discussed. The main source of contaminants in the Wadden Sea are the rivers Rhine (via de Dutch coastal zone), Elbe and Weser. The Wadden Sea is not a sink for contaminants and adsorbed contaminants are transported from east to west. The surface sediments of the Wadden Sea are an important source for contaminants to the water above. The input and concentration of most contaminants have significantly decreased in water, sediments, organisms (e.g., mussel, flounder and bird eggs) in various parts of the Wadden Sea in the last three decades. Remarkably, the Cd concentration in mussels is increasing the last decades. In recent decades, the effects of contaminants on organisms (e.g., flounder, seal) have fallen markedly. Most of the affected populations have recovered, except for TBT induced effects in snails. Little is known about the concentration and effects of most emerging contaminants and the complex environmental mixtures of contaminants. It is recommended to install an international coordinated monitoring programme for contaminants and their effects in the whole Wadden Sea and to identify the chemical contaminants that really cause the effect.

Do contamination of and exposure to chicken meat and water drive the temporal dynamics of Campylobacter cases?

PubMed

David, J M; Pollari, F; Pintar, K D M; Nesbitt, A; Butler, A J; Ravel, A

2017-11-01

Campylobacteriosis, the most frequent bacterial enteric disease, shows a clear yet unexplained seasonality. The study purpose was to explore the influence of seasonal fluctuation in the contamination of and in the behaviour exposures to two important sources of Campylobacter on the seasonality of campylobacteriosis. Time series analyses were applied to data collected through an integrated surveillance system in Canada in 2005-2010. Data included sporadic, domestically-acquired cases of Campylobacter jejuni infection, contamination of retail chicken meat and of surface water by C. jejuni, and exposure to each source through barbequing and swimming in natural waters. Seasonal patterns were evident for all variables with a peak in summer for human cases and for both exposures, in fall for chicken meat contamination, and in late fall for water contamination. Time series analyses showed that the observed campylobacteriosis summer peak could only be significantly linked to behaviour exposures rather than sources contamination (swimming rather than water contamination and barbequing rather than chicken meat contamination). The results indicate that the observed summer increase in human cases may be more the result of amplification through more frequent risky exposures rather than the result of an increase of the Campylobacter source contamination.

External Contamination Control of Attached Payloads on the International Space Station

NASA Technical Reports Server (NTRS)

Soares, Carlos E.; Mikatarian, Ronald R.; Olsen, Randy L.; Huang, Alvin Y.; Steagall, Courtney A.; Schmidl, William D.; Wright, Bruce D.; Koontz, Steven

2012-01-01

The International Space Station (ISS) is an on-orbit platform for science utilization in low Earth orbit with multiple sites for external payloads with exposure to the natural and induced environments. Contamination is one of the induced environments that can impact performance, mission success and science utilization on the vehicle. This paper describes the external contamination control requirements and integration process for externally mounted payloads on the ISS. The external contamination control requirements are summarized and a description of the integration and verification process is detailed to guide payload developers in the certification process of attached payloads on the vehicle. A description of the required data certification deliverables covers the characterization of contamination sources. Such characterization includes identification, usage and operational data for each class of contamination source. Classes of external contamination sources covered are vacuum exposed materials, sources of leakage, vacuum venting and thrusters. ISS system level analyses are conducted by the ISS Space Environments Team to certify compliance with external contamination control requirements. This paper also addresses the ISS induced contamination environment at attached payload sites, both at the requirements level as well as measurements made on ISS.

Saltwater contamination in the managed low-lying farmland of the Venice coast, Italy: An assessment of vulnerability.

PubMed

Da Lio, Cristina; Carol, Eleonora; Kruse, Eduardo; Teatini, Pietro; Tosi, Luigi

2015-11-15

The original morphology and hydrogeology of many low-lying coastlands worldwide have been significantly modified over the last century through river diversion, embankment built-up, and large-scale land reclamation projects. This led to a progressive shifting of the groundwater-surficial water exchanges from naturally to anthropogenically driven. In this human-influenced hydrologic landscape, the saltwater contamination usually jeopardizes the soil productivity. In the coastland south of Venice (Italy), several well log measurements, chemical and isotope analyses have been performed over the last decade to characterize the occurrence of the salt contamination. The processing of this huge dataset highlights a permanent variously-shaped saline contamination up to 20km inland, with different conditions in relation with the various geomorphological features of the area. The results point out the important role of the land reclamation in shaping the present-day salt contamination and reveal the contribution of precipitation, river discharge, lagoon and sea water to the shallow groundwater in the various coastal sectors. Moreover, an original vulnerability map to salt contamination in relation to the farmland productivity has been developed taking into account the electrical conductivity of the upper aquifer in the worst condition, the ground elevation, and the distance from salt and fresh surface water sources. Finally, the study allows highlighting the limit of traditional investigations in monitoring saltwater contamination at the regional scale in managed Holocene coastal environments. Possible improvements are outlined. Copyright © 2015 Elsevier B.V. All rights reserved.

Groundwater contaminants in the deep benthic zone of urban streams in Canada (Invited)

NASA Astrophysics Data System (ADS)

Roy, J. W.; Bickerton, G.

2010-12-01

There is little information available on the potential threat that groundwater containing land-based contaminants poses to aquatic ecosystems in urban environments. In this study, a rapid screening approach was applied at the stream reach-scale for eight urban streams (reaches from 100 to < 1000 m). The objective was to determine what types of groundwater contaminants could be detected in the deeper benthic zone of these streams, if any, to start to address questions of whether such contaminants are a concern and which types are the most problematic. The benthic community may be especially at risk since it may experience higher contaminant concentrations than the stream itself due to fewer losses from sorption, degradation and volatilization processes. For each stream, groundwater samples from below the stream bed (typically 25-75 cm) were collected using a drive-point mini-profiler at intervals of 10-15 m along the stream and were subsequently analysed for general chemistry and a wide range of common and emerging urban contaminants. For a few test streams with known contamination, the area of contamination was identified with this technique. In addition, previously unknown contaminants or areas of contamination were identified at all nine streams. Identified contaminants included benzene and other petroleum hydrocarbons, fuel oxygenates (e.g. MTBE), perchlorate, pesticides, artificial sweeteners, and various chlorinated solvent compounds. In addition, elevated levels of nitrate, phosphate, some heavy metals, including cadmium and arsenic, and elevated chloride (likely indicating road salt) were detected. Most streams had many different types of contaminants, often overlapping over small stretches, and together often covering substantial portions of the monitored reach. The findings provide support for this screening approach for delineating areas of potential ecological concern and identifying possible sources of groundwater contamination, for urban settings. They also suggest that the presence of multiple groundwater contaminants may be a more common threat to the benthic community of urban streams than currently perceived.

Aliphatic and polycyclic aromatic hydrocarbons in Gulf of Trieste sediments (northern Adriatic): potential impacts of maritime traffic.

PubMed

Bajt, Oliver

2014-09-01

The Gulf of Trieste (northern Adriatic) is one of the most urbanized and industrialized areas in the northern Adriatic, with intense maritime traffic experienced at multiple ports. The impact of maritime traffic on contamination by hydrocarbons in this area was assessed. Concentrations of hydrocarbons were higher near the expected contamination sources and still elevated in the adjacent offshore areas. Aliphatic hydrocarbons were mainly of petrogenic origin, with some contribution of biogenic origin. A continuous contamination by aliphatic hydrocarbons and degradation processes were hypothesized. Concentrations of total polycyclic aromatic hydrocarbons (PAH) were generally greater near the contamination sources. Compared to the prevailing pyrolytic origin, the petrogenic PAH origin seemed to be less important, but not negligible. Results revealed that intensive maritime traffic is a probable source of contamination by hydrocarbons in the investigated area, which is largely limited to areas near the contamination sources.

Identifying the starting point of a spreading process in complex networks.

PubMed

Comin, Cesar Henrique; Costa, Luciano da Fontoura

2011-11-01

When dealing with the dissemination of epidemics, one important question that can be asked is the location where the contamination began. In this paper, we analyze three spreading schemes and propose and validate an effective methodology for the identification of the source nodes. The method is based on the calculation of the centrality of the nodes on the sampled network, expressed here by degree, betweenness, closeness, and eigenvector centrality. We show that the source node tends to have the highest measurement values. The potential of the methodology is illustrated with respect to three theoretical complex network models as well as a real-world network, the email network of the University Rovira i Virgili.

CO2-efflux measurements for evaluating source zone natural attenuation rates in a petroleum hydrocarbon contaminated aquifer.

PubMed

Sihota, Natasha J; Singurindy, Olga; Mayer, K Ulrich

2011-01-15

In order to gain regulatory approval for source zone natural attenuation (SZNA) at hydrocarbon-contaminated sites, knowledge regarding the extent of the contamination, its tendency to spread, and its longevity is required. However, reliable quantification of biodegradation rates, an important component of SZNA, remains a challenge. If the rate of CO(2) gas generation associated with contaminant degradation can be determined, it may be used as a proxy for the overall rate of subsurface biodegradation. Here, the CO(2)-efflux at the ground surface is measured using a dynamic closed chamber (DCC) method to evaluate whether this technique can be used to assess the areal extent of the contaminant source zone and the depth-integrated rate of contaminant mineralization. To this end, a field test was conducted at the Bemidji, MN, crude oil spill site. Results indicate that at the Bemidji site the CO(2)-efflux method is able to both delineate the source zone and distinguish between the rates of natural soil respiration and contaminant mineralization. The average CO(2)-efflux associated with contaminant degradation in the source zone is estimated at 2.6 μmol m(-2) s(-1), corresponding to a total petroleum hydrocarbon mineralization rate (expressed as C(10)H(22)) of 3.3 g m(-2) day(-1).

A hospital outbreak of Legionella from a contaminated water supply.

PubMed

Tercelj-Zorman, Marjeta; Seljak, Marija; Stare, Janez; Mencinger, Joze; Rakovec, Joze; Rylander, Ragnar; Strle, Franc

2004-03-01

The authors performed a cross-sectional epidemiological survey to investigate the source of a hospital Legionella outbreak originating in contaminated water. Water temperature and air humidity were measured around possible contamination sources. A dead-end pipe was found to contain Legionella pneumophila serogroup 1. All individuals who acquired legionellosis had spent at least 30 min within 2 m of the contamination source. Among staff, 41 of 71 were exposed, and 31 of these fell ill. All 7 patients exposed to the contaminated water acquired legionellosis. None of the 94 bed-ridden patients from the same units developed the disease. An aerosol with 60% relative air humidity was formed near the suspect water faucets, but the humidity fell rapidly farther from the water source, suggesting that desiccation decreased the risk of infection. The healthy personnel and patients closest to the source acquired legionellosis, suggesting that risk was related less to compromised patients than to exposure.

Faecal contamination of drinking water in a Brazilian shanty town: importance of household storage and new human faecal marker testing.

PubMed

Copeland, Curtis C; Beers, Benjamin B; Thompson, Meghan R; Fitzgerald, Relana P; Barrett, Leah J; Sevilleja, Jesus E; Alencar, Sayonara; Lima, Aldo A M; Guerrant, Richard L

2009-06-01

Worldwide, contaminated drinking water poses a major health threat, particularly to child development. Diarrhoea represents a large part of the water-related disease burden and enteric infections have been linked to nutritional and growth shortfalls as well as long-term physical and cognitive impairment in children. Previous studies detailed the frequency of infection and the consequences for child health in a shanty town in north-east Brazil. To determine the frequency of contaminated water, we measured faecal contamination in primary drinking water samples from 231 randomly selected households. Risk for contamination was compared across source and storage types. Nearly a third of the study households (70/231: 30.3%) had contaminated drinking water; the source with the highest frequency of contamination was well water (23/24: 95.8%). For tap water, the type of storage had a significant effect on the susceptibility to contamination (chi(2) = 12.090; p = 0.007). The observed pattern of contamination demonstrated the relative potential contributions of both source and storage. With evidence that supports the inclusion of source and storage in water quality surveys, this study, like others, suggests that contaminated drinking water in storage vessels may be an important factor for the documented diarrhoea disease burden in the Brazilian shanty town.

Comparison of Chlorinated Ethenes DNAPL Reductive Dechlorination by Indigenous and Evanite culture with Surfactant Tween-80

NASA Astrophysics Data System (ADS)

Kwon, S.; Hong, S.; Kim, R.; Kim, N.; Ahn, H.; Lee, S.; Kim, Y.

2010-12-01

Although many innovative technologies have been developed to enhance remediation of chlorinated ethenes(e.g. tetrachloroethene[PCE], trichloroethene[TCE])DNAPL source zones, they have been ineffective in reducing contaminant concentration to regulatory end points. Thus, combination of surfactant flushing process that removes significant contaminant mass with microbial reductive dechlorination, posttreatment "polishing step" to control the remaining DNAPL that may serve as a source of reducing equivalents and stimulate the dechlorinating bacterial communities may be an attractive remediation process alternatively. Microcosm studies were conducted to explore chlorinated ethenes, PCE/TCE of 3 ~ 30 mg/L dechlorination by indigenous microbial communities from TCE DNAPL source zones of Korea and Evanite culture in the presence of Tween-80 of 10 ~ 5,000 mg/L. In the microcosms for indigenous microbial communities, by-products(e.g. c-DCE, vinyl chloride) of reductive dechlorination of PCE/TCE were not detected. This results suggest dechlorinating bacteria might be not exist or high concentration of chlorinated ethenes inhibit activity of dechlorinating bacteria in indigenous microbial communities. But VFAs like acetate, methane and hydrogen gas from fermentation of Tween-80 were detected. So Tween-80 might estimated to serve as a source of reducing equivalents. To evaluate the dechlorinating ability of Evanite-culture, we added Evanite-culture to the microcosms for indigenous bacteria and monitored by-products of reductive dechlorination of PCE/TCE and VFAs and hydrogen gas.

Characterizing Long-term Contaminant Mass Discharge and the Relationship Between Reductions in Discharge and Reductions in Mass for DNAPL Source Areas

PubMed Central

Matthieu, D.E.; Carroll, K.C.; Mainhagu, J.; Morrison, C.; McMillan, A.; Russo, A.; Plaschke, M.

2013-01-01

The objective of this study was to characterize the temporal behavior of contaminant mass discharge, and the relationship between reductions in contaminant mass discharge and reductions in contaminant mass, for a very heterogeneous, highly contaminated source-zone field site. Trichloroethene is the primary contaminant of concern, and several lines of evidence indicate the presence of organic liquid in the subsurface. The site is undergoing groundwater extraction for source control, and contaminant mass discharge has been monitored since system startup. The results show a significant reduction in contaminant mass discharge with time, decreasing from approximately 1 to 0.15 kg/d. Two methods were used to estimate the mass of contaminant present in the source area at the initiation of the remediation project. One was based on a comparison of two sets of core data, collected 3.5 years apart, which suggests that a significant (~80%) reduction in aggregate sediment-phase TCE concentrations occurred between sampling events. The second method was based on fitting the temporal contaminant mass discharge data with a simple exponential source-depletion function. Relatively similar estimates, 784 and 993 kg, respectively, were obtained with the two methods. These data were used to characterize the relationship between reductions in contaminant mass discharge (CMDR) and reductions in contaminant mass (MR). The observed curvilinear relationship exhibits a reduction in contaminant mass discharge essentially immediately upon initiation of mass reduction. This behavior is consistent with a system wherein significant quantities of mass are present in hydraulically poorly accessible domains for which mass removal is influenced by rate-limited mass transfer. The results obtained from the present study are compared to those obtained from other field studies to evaluate the impact of system properties and conditions on mass-discharge and mass-removal behavior. The results indicated that factors such as domain scale, hydraulic-gradient status (induced or natural), and flushing-solution composition had insignificant impact on the CMDR-MR profiles and thus on underlying mass-removal behavior. Conversely, source-zone age, through its impact on contaminant distribution and accessibility, was implicated as a critical factor influencing the nature of the CMDR-MR relationship. PMID:23528743

A geographical information system (GIS) as a tool for microbial risk assessment in catchment areas of drinking water reservoirs.

PubMed

Kistemann, T; Dangendorf, F; Exner, M

2001-03-01

The main tributaries of three drinking water reservoirs of Northrhine-Westfalia (Germany) were monitored within a 14-month period mainly for bacterial and parasitic contamination. In this context a detailed geo-ecological characterisation within the differing catchment areas was carried out to reveal a reliable informational basis for tracing back the origin of microbial loads present in the watercourses. To realise a microbial risk assessing geo-ecological information system (MRA-GIS), a Geographical Information System (GIS) has been implemented for the study areas. The results of the microbiological investigations of the watercourses showed an input of pathogens into all three of the tributaries. It could be demonstrated that the use of MRA-GIS database and some GIS-techniques substantially support the spatial analysis of the microbial contamination patterns. From the hygienic point of view, it is of the utmost importance to protect catchment areas of surface water reservoirs from microbial contamination stemming from human activities and animal sources. This constitutes essential part of the multi-barrier concept which stresses the importance of reducing diffuse and point pollution in catchment areas of water resources intended for human consumption. MRA-GIS proves to be helpful to manage multi-barrier water protection in catchment areas and ideally assists the application of the HACCP concept on drinking water production.

Detection of human adenovirus, rotavirus and enterovirus in water samples collected on dairy farms from Tenente Portela, Northwest of Rio Grande do Sul, Brazil

PubMed Central

Spilki, Fernando Rosado; da Luz, Roger Bordin; Fabres, Rafael Bandeira; Soliman, Mayra Cristina; Kluge, Mariana; Fleck, Juliane Deise; Rodrigues, Manoela Tressoldi; Comerlato, Juliana; Cenci, Alexander; Cerva, Cristine; Dasso, Maurício Gautério; Roehe, Paulo Michel

2013-01-01

Viral gastroenteritis and other waterborne diseases are a major concern for health in Brazil. A number of studies were conducted about the presence of viruses on water samples from Brazilian areas. However, the knowledge about the occurrence of viral contamination of drinking water sources in rural settings of the country is insufficient. On the present work, 15 samples from 5 dairy farms located at the municipality of Tenente Portela were collected and analysed for the presence of human adenoviruses (HAdV), as well as human enteroviruses (EV) and rotaviruses (RV). HAdV was present on 66.66% of the water samples, and have been found in all samples from artesian wells and springs, which are used as sources of drinking water for the individuals inhabiting those farms. EV and RV found only in one sample each. The detection rates of HAdV on the water from these dairy farms are alarming and point towards a situation of elevated environmental contamination by fecal microorganisms of human origin and poor basic sanitation conditions. PMID:24516464

A cluster of cases of nosocomial legionnaires disease linked to a contaminated hospital decorative water fountain.

PubMed

Palmore, Tara N; Stock, Frida; White, Margaret; Bordner, MaryAnn; Michelin, Angela; Bennett, John E; Murray, Patrick R; Henderson, David K

2009-08-01

Nosocomial outbreaks of Legionnaires disease have been linked to contaminated water in hospitals. Immunocompromised patients are particularly vulnerable and, when infected, have a high mortality rate. We report the investigation of a cluster of cases of nosocomial pneumonia attributable to Legionella pneumophila serogroup 1 that occurred among patients on our stem cell transplantation unit. We conducted a record review to identify common points of potential exposure, followed by environmental and water sampling for Legionella species from those sources. We used an air sampler to in an attempt to detect aerosolized Legionella and pulsed-field gel electrophoresis to compare clinical and environmental isolates. The most likely sources identified were the water supply in the patients' rooms and a decorative fountain in the radiation oncology suite. Samples from the patients' rooms did not grow Legionella species. Cultures of the fountain, which had been restarted 4 months earlier after being shut off for 5 months, yielded L. pneumophila serogroup 1. The isolates from both patients and the fountain were identical by pulsed-field gel electrophoresis. Both patients developed pneumonia within 10 days of completing radiation therapy, and each reported having observed the fountain at close range. Both patients' infections were identified early and treated promptly, and both recovered. This cluster was caused by contamination of a decorative fountain despite its being equipped with a filter and ozone generator. Fountains are a potential source of nosocomial Legionnaires disease despite standard maintenance and sanitizing measures. In our opinion, fountains present unacceptable risk in hospitals serving immunocompromised patients.

Groundwater source contamination mechanisms: Physicochemical profile clustering, risk factor analysis and multivariate modelling

NASA Astrophysics Data System (ADS)

Hynds, Paul; Misstear, Bruce D.; Gill, Laurence W.; Murphy, Heather M.

2014-04-01

An integrated domestic well sampling and "susceptibility assessment" programme was undertaken in the Republic of Ireland from April 2008 to November 2010. Overall, 211 domestic wells were sampled, assessed and collated with local climate data. Based upon groundwater physicochemical profile, three clusters have been identified and characterised by source type (borehole or hand-dug well) and local geological setting. Statistical analysis indicates that cluster membership is significantly associated with the prevalence of bacteria (p = 0.001), with mean Escherichia coli presence within clusters ranging from 15.4% (Cluster-1) to 47.6% (Cluster-3). Bivariate risk factor analysis shows that on-site septic tank presence was the only risk factor significantly associated (p < 0.05) with bacterial presence within all clusters. Point agriculture adjacency was significantly associated with both borehole-related clusters. Well design criteria were associated with hand-dug wells and boreholes in areas characterised by high permeability subsoils, while local geological setting was significant for hand-dug wells and boreholes in areas dominated by low/moderate permeability subsoils. Multivariate susceptibility models were developed for all clusters, with predictive accuracies of 84% (Cluster-1) to 91% (Cluster-2) achieved. Septic tank setback was a common variable within all multivariate models, while agricultural sources were also significant, albeit to a lesser degree. Furthermore, well liner clearance was a significant factor in all models, indicating that direct surface ingress is a significant well contamination mechanism. Identification and elucidation of cluster-specific contamination mechanisms may be used to develop improved overall risk management and wellhead protection strategies, while also informing future remediation and maintenance efforts.

A cluster of nosocomial Legionnaire’s disease linked to a contaminated hospital decorative water fountain

PubMed Central

Palmore, Tara N.; Stock, Frida; White, Margaret; Bordner, MaryAnn; Michelin, Angela; Bennett, John E.; Murray, Patrick R.; Henderson, David K.

2009-01-01

Background Nosocomial outbreaks of Legionnaire’s disease have been linked to contaminated water in hospitals. Immunocompromised patients are particularly vulnerable and, when infected, have a high mortality rate. We report the investigation of a cluster of nosocomial pneumonia due to Legionella pneumophila serogroup 1 that occurred among patients on our stem cell transplantation unit. Methods We conducted a record review to identify common points of potential exposure, followed by environmental and water sampling for Legionella spp. from those sources. We used an air sampler in an attempt to detect aerosolized Legionella, and pulsed-field gel electrophoresis to compare clinical and environmental isolates. Results The most likely sources identified were the water supply in the patients’ rooms and a decorative fountain in the radiation oncology suite. Samples from the patients’ rooms did not grow Legionella species. Cultures of the fountain, which had been restarted 4 months earlier after being shut off for 5 months, yielded L. pneumophila serogroup 1. The isolates from both patients and the fountain were identical by pulsed-field gel electrophoresis. Both patients developed pneumonia within 10 days of completing radiation therapy, and each reported having observed the fountain at close range. Both patients’ infections were identified early and treated promptly, and both recovered. Conclusions This cluster was caused by contamination of a decorative fountain despite its being equipped with a filter and ozone generator. Fountains are a potential source of nosocomial Legionnaire’s disease despite standard maintenance and sanitizing measures. In our opinion, fountains present unacceptable risk in hospitals serving immunocompromised patients. PMID:19580436

D-Optimal Experimental Design for Contaminant Source Identification

NASA Astrophysics Data System (ADS)

Sai Baba, A. K.; Alexanderian, A.

2016-12-01

Contaminant source identification seeks to estimate the release history of a conservative solute given point concentration measurements at some time after the release. This can be mathematically expressed as an inverse problem, with a linear observation operator or a parameter-to-observation map, which we tackle using a Bayesian approach. Acquisition of experimental data can be laborious and expensive. The goal is to control the experimental parameters - in our case, the sparsity of the sensors, to maximize the information gain subject to some physical or budget constraints. This is known as optimal experimental design (OED). D-optimal experimental design seeks to maximize the expected information gain, and has long been considered the gold standard in the statistics community. Our goal is to develop scalable methods for D-optimal experimental designs involving large-scale PDE constrained problems with high-dimensional parameter fields. A major challenge for the OED, is that a nonlinear optimization algorithm for the D-optimality criterion requires repeated evaluation of objective function and gradient involving the determinant of large and dense matrices - this cost can be prohibitively expensive for applications of interest. We propose novel randomized matrix techniques that bring down the computational costs of the objective function and gradient evaluations by several orders of magnitude compared to the naive approach. The effect of randomized estimators on the accuracy and the convergence of the optimization solver will be discussed. The features and benefits of our new approach will be demonstrated on a challenging model problem from contaminant source identification involving the inference of the initial condition from spatio-temporal observations in a time-dependent advection-diffusion problem.

Spatial distribution and sources of heavy metals in natural pasture soil around copper-molybdenum mine in Northeast China.

PubMed

Wang, Zhiqiang; Hong, Chen; Xing, Yi; Wang, Kang; Li, Yifei; Feng, Lihui; Ma, Silu

2018-06-15

The characterization of the content and source of heavy metals are essential to assess the potential threat of metals to human health. The present study collected 140 topsoil samples around a Cu-Mo mine (Wunugetushan, China) and investigated the concentrations and spatial distribution pattern of Cr, Ni, Zn, Cu, Mo and Cd in soil using multivariate and geostatistical analytical methods. Results indicated that the average concentrations of six heavy metals, especially Cu and Mo, were obviously higher than the local background values. Correlation analysis and principal component analysis divided these metals into three groups, including Cr and Ni, Cu and Mo, Zn and Cd. Meanwhile, the spatial distribution maps of heavy metals indicated that Cr and Ni in soil were no notable anthropogenic inputs and mainly controlled by natural factors because their spatial maps exhibited non-point source contamination. The concentrations of Cu and Mo gradually decreased with distance away from the mine area, suggesting that human mining activities may be crucial in the spreading of contaminants. Soil contamination of Zn were associated with livestock manure produced from grazing. In addition, the environmental risk of heavy metal pollution was assessed by geo-accumulation index. All the results revealed that the spatial distribution of heavy metals in soil were in agreement with the local human activities. Investigating and identifying the origin of heavy metals in pasture soil will lay the foundation for taking effective measures to preserve soil from the long-term accumulation of heavy metals. Copyright © 2018 Elsevier Inc. All rights reserved.

Natural and anthropogenic factors affecting the groundwater quality in Serbia.

PubMed

Devic, Gordana; Djordjevic, Dragana; Sakan, Sanja

2014-01-15

Various chemometric techniques were used to analyze the quality of groundwater data sets. Seventeen water quality parameters: the cations Na, K, Ca, Mg, the anions Cl, SO4, NO3, HCO3 and nine trace elements Pb, As, Mn, Ni, Cu, Cd, Fe, Zn and Cr were measured at 66 different key sampling sites in ten representative areas (low land-Northern Autonomous Province of Serbia, Vojvodina and central Serbia) for the summer period of 2009. HCA grouped the sample sites into four clusters based on the similarities of the characteristics of the groundwater quality. DA showed two parameters, HCO3 and Zn, affording more than 90% correct assignments in the spatial analysis of four/three different regions in Serbia. Factor analysis was applied on the log-transformed data sets and allowed the identification of a reduced number of factors with hydrochemical meaning. The results showed severe pollution with Mn, As, NO3, Ni, Pb whereby anthropogenic origin of these contaminants was indicated. The pollution comes from both scattered point sources (industrial and urban effluent) and diffuse source agricultural activity. These samples may not be suitable for human consumption; the water quality belongs to class III/IV (contaminated). The Fe anomalies (7.1mg/L) in the water from the Vetrnica site can be attributed to natural sources, such as the dissolution of rock masses and rock fragments. The serious groundwater contamination with As (25.7-137.8 μg/L) in the area of Banat (Northern Autonomous Province of Serbia, Vojvodina) and a sample No. 9 at the Great Morava River requires urgent attention. © 2013.

Point sources of emerging contaminants along the Colorado River Basin: Source water for the arid Southwestern United States

USGS Publications Warehouse

Jones-Lepp, Tammy L.; Sanchez, Charles; Alvarez, David A.; Wilson, Doyle C.; Taniguchi-Fu, Randi-Laurant

2012-01-01

Emerging contaminants (ECs) (e.g., pharmaceuticals, illicit drugs, personal care products) have been detected in waters across the United States. The objective of this study was to evaluate point sources of ECs along the Colorado River, from the headwaters in Colorado to the Gulf of California. At selected locations in the Colorado River Basin (sites in Colorado, Utah, Nevada, Arizona, and California), waste stream tributaries and receiving surface waters were sampled using either grab sampling or polar organic chemical integrative samplers (POCIS). The grab samples were extracted using solid-phase cartridge extraction (SPE), and the POCIS sorbents were transferred into empty SPEs and eluted with methanol. All extracts were prepared for, and analyzed by, liquid chromatography–electrospray-ion trap mass spectrometry (LC–ESI-ITMS). Log DOW values were calculated for all ECs in the study and compared to the empirical data collected. POCIS extracts were screened for the presence of estrogenic chemicals using the yeast estrogen screen (YES) assay. Extracts from the 2008 POCIS deployment in the Las Vegas Wash showed the second highest estrogenicity response. In the grab samples, azithromycin (an antibiotic) was detected in all but one urban waste stream, with concentrations ranging from 30 ng/L to 2800 ng/L. Concentration levels of azithromycin, methamphetamine and pseudoephedrine showed temporal variation from the Tucson WWTP. Those ECs that were detected in the main surface water channels (those that are diverted for urban use and irrigation along the Colorado River) were in the region of the limit-of-detection (e.g., 10 ng/L), but most were below detection limits.

[Accidents with exposure to biological material contaminated with HIV in workers at a third level hospital in Madrid].

PubMed

García de Codes Ilario, Aurelia; de Juanes Pardo, José Ramón; Arrazola Martínez, M del Pilar; Jaén Herreros, Felisa; Sanz Gallardo, M Inmaculada; Lago López, Emilia

2004-01-01

Human Immunodeficiency Virus (HIV) is an occupational hazard among healthcare professionals accidentally contaminated with HIV-positive blood. This study is aimed at describing the characteristics of the accidents involving blood of HIV-positive patients recorded over a sixteen-year period at a general hospital. Epidemiological study of the accidents reported in 2001 involving biological material from an HIV-positive source by the healthcare personnel of a general hospital throughout the 1986-2001 period entailing the presence of biological material from HIV-positive serology individuals. Individual, time and place-related variables, in addition to the initial serologies and those throughout the protocolized follow-up were studied for those individuals involved in these accidents. A total 550 accidents entailing an HIV-positive source were reported. The average number of accidents was 34.4/year. The accidental exposure rate for the period under study was 7.5/1000 workers/year. The professional group showing the highest accident rate was the nursing staff (54.4%). Percutaneous injuries were the most frequent (80.2%). The mean exposure rate was 2.6/100 beds/year. The anatomical areas involved to the greatest degree were the fingers (75.6%). A total 53.4% of those injured completed the serological follow-up without having shown any seroconversion. Throughout the sixteen-year period under study, the annual incidence of accidents involving an HIV-positive source increased from the 27 accidents reported in 1986 to the 60 accidents reported in 1990, there having been a downward trend as of that point in time, to the point of 12 accidents having been recorded in 2001.

Rooftop Runoff as a Source of Contamination: A Review

EPA Science Inventory

Scientific reports concerning chemical and microbiological contaminant levels of rainwater runoff from rooftop collection in both urban and rural areas are reviewed. This alternative source of water has been documented to often contain substantial amounts of contaminants. Studi...

How to Decide? Multi-Objective Early-Warning Monitoring Networks for Water Suppliers

NASA Astrophysics Data System (ADS)

Bode, Felix; Loschko, Matthias; Nowak, Wolfgang

2015-04-01

Groundwater is a resource for drinking water and hence needs to be protected from contaminations. However, many well catchments include an inventory of known and unknown risk sources, which cannot be eliminated, especially in urban regions. As a matter of risk control, all these risk sources should be monitored. A one-to-one monitoring situation for each risk source would lead to a cost explosion and is even impossible for unknown risk sources. However, smart optimization concepts could help to find promising low-cost monitoring network designs. In this work we develop a concept to plan monitoring networks using multi-objective optimization. Our considered objectives are to maximize the probability of detecting all contaminations, to enhance the early warning time before detected contaminations reach the drinking water well, and to minimize the installation and operating costs of the monitoring network. Using multi-objectives optimization, we avoid the problem of having to weight these objectives to a single objective-function. These objectives are clearly competing, and it is impossible to know their mutual trade-offs beforehand - each catchment differs in many points and it is hardly possible to transfer knowledge between geological formations and risk inventories. To make our optimization results more specific to the type of risk inventory in different catchments we do risk prioritization of all known risk sources. Due to the lack of the required data, quantitative risk ranking is impossible. Instead, we use a qualitative risk ranking to prioritize the known risk sources for monitoring. Additionally, we allow for the existence of unknown risk sources that are totally uncertain in location and in their inherent risk. Therefore, they can neither be located nor ranked. Instead, we represent them by a virtual line of risk sources surrounding the production well. We classify risk sources into four different categories: severe, medium and tolerable for known risk sources and an extra category for the unknown ones. With that, early warning time and detection probability become individual objectives for each risk class. Thus, decision makers can identify monitoring networks valid for controlling the top risk sources, and evaluate the capabilities (or search for least-cost upgrades) to also cover moderate, tolerable and unknown risk sources. Monitoring networks, which are valid for the remaining risk also cover all other risk sources, but only with a relatively poor early-warning time. The data provided for the optimization algorithm are calculated in a preprocessing step by a flow and transport model. It simulates, which potential contaminant plumes from the risk sources would be detectable where and when by all possible candidate positions for monitoring wells. Uncertainties due to hydro(geo)logical phenomena are taken into account by Monte-Carlo simulations. These include uncertainty in ambient flow direction of the groundwater, uncertainty of the conductivity field, and different scenarios for the pumping rates of the production wells. To avoid numerical dispersion during the transport simulations, we use particle-tracking random walk methods when simulating transport.

Lead distribution and its potential risk to the environment: lesson learned from environmental monitoring of abandon mine.

PubMed

Nobuntou, Wanida; Parkpian, Preeda; Oanh, Nguyen Thi Kim; Noomhorm, Athapol; Delaune, R D; Jugsujinda, Aroon

2010-11-01

There are many abandon and existing mines (tin, lead and zinc) in the mountainous areas of Thailand. Toxic elements including heavy metals such as lead (Pb), cadmium (Cd) and arsenic (As) have been released and transported from the mining sites to the adjacent landscape. In Thong Pha Phum District, Kanchanaburi Province, Thailand Pb contamination in the vicinity of the mine has occurred which could lead to potential health problems in downstream communities. To better understand current status of Pb contamination and accumulation in the surrounding environment and potential health impact, surface sediment, soil and plant samples were collected seasonally from representative monitoring sites along the aquatic track or flow regime. Potential health risk was determined using hazard quotient (HQ) as an index for local inhabitants who consume rice. Environmental monitoring illustrated that Pb concentrations in the surface sediment was as high as 869.4 mg kg(-1) dry weight and varied differently among stations sampled. Lead content in agricultural soil ranged between 137.8 to 613.5 mg kg(-1) dry weight and was inversely proportion to the distance from the point source. Moreover Pb was transported from the point source to down hill areas. At the highly polluted monitoring stations (S1, S2, and S3), concentrations of Pb exceeded the maximum allowable concentration for Pb in agricultural soil (300 mg kg(-1)) by 1.7-2 times. The Pb in soil was primarily associated with Fe/Mn oxides bound fraction (46-56%) followed by the organic bound fraction (25-30%). Lead uptake by plant varied and was species dependent. However root and tuber crops like cassava (19.92 mg Pb kg(-1) dry weight) and curcumin (3.25 mg Pb kg(-1) dry weight) could have removed Pb from the soil which suggest growing root crops in Pb contaminated soils should be avoided. However Cd, a co-contaminant at one of monitored stations (S4) yielded rice grain with Cd exceeding the maximum allowable concentration suggesting some potential health risk (HQ = 5.34) if people consume rice grown at this station. Overall result shows a low risk associated with Pb release into the environment.

The Relationship Between Partial Contaminant Source Zone Remediation and Groundwater Plume Attenuation

NASA Astrophysics Data System (ADS)

Falta, R. W.

2004-05-01

Analytical solutions are developed that relate changes in the contaminant mass in a source area to the behavior of biologically reactive dissolved contaminant groundwater plumes. Based on data from field experiments, laboratory experiments, numerical streamtube models, and numerical multiphase flow models, the chemical discharge from a source region is assumed to be a nonlinear power function of the fraction of contaminant mass removed from the source zone. This function can approximately represent source zone mass discharge behavior over a wide range of site conditions ranging from simple homogeneous systems, to complex heterogeneous systems. A mass balance on the source zone with advective transport and first order decay leads to a nonlinear differential equation that is solved analytically to provide a prediction of the time-dependent contaminant mass discharge leaving the source zone. The solution for source zone mass discharge is coupled semi-analytically with a modified version of the Domenico (1987) analytical solution for three-dimensional reactive advective and dispersive transport in groundwater. The semi-analytical model then employs the BIOCHLOR (Aziz et al., 2000; Sun et al., 1999) transformations to model sequential first order parent-daughter biological decay reactions of chlorinated ethenes and ethanes in the groundwater plume. The resulting semi-analytic model thus allows for transient simulation of complex source zone behavior that is fully coupled to a dissolved contaminant plume undergoing sequential biological reactions. Analyses of several realistic scenarios show that substantial changes in the ground water plume can result from the partial removal of contaminant mass from the source zone. These results, however, are sensitive to the nature of the source mass reduction-source discharge reduction curve, and to the rates of degradation of the primary contaminant and its daughter products in the ground water plume. Aziz, C.E., C.J. Newell, J.R. Gonzales, P. Haas, T.P. Clement, and Y. Sun, 2000, BIOCHLOR Natural Attenuation Decision Support System User's Manual Version 1.0, US EPA Report EPA/600/R-00/008 Domenico, P.A., 1987, An analytical model for multidimensional transport of a decaying contaminant species, J. Hydrol., 91: 49-58. Sun, Y., J.N. Petersen, T.P. Clement, and R.S. Skeen, 1999, A new analytical solution for multi-species transport equations with serial and parallel reactions, Water Resour. Res., 35(1): 185-190.

Multicenter outbreak of infections by Saprochaete clavata, an unrecognized opportunistic fungal pathogen.

PubMed

Vaux, Sophie; Criscuolo, Alexis; Desnos-Ollivier, Marie; Diancourt, Laure; Tarnaud, Chloé; Vandenbogaert, Matthias; Brisse, Sylvain; Coignard, Bruno; Dromer, Françoise

2014-12-16

Rapidly fatal cases of invasive fungal infections due to a fungus later identified as Saprochaete clavata were reported in France in May 2012. The objectives of this study were to determine the clonal relatedness of the isolates and to investigate possible sources of contamination. A nationwide alert was launched to collect cases. Molecular identification methods, whole-genome sequencing (WGS), and clone-specific genotyping were used to analyze recent and historical isolates, and a case-case study was performed. Isolates from thirty cases (26 fungemias, 22 associated deaths at day 30) were collected between September 2011 and October 2012. Eighteen cases occurred within 8 weeks (outbreak) in 10 health care facilities, suggesting a common source of contamination, with potential secondary cases. Phylogenetic analysis identified one clade (clade A), which accounted for 16/18 outbreak cases. Results of microbiological investigations of environmental, drug, or food sources were negative. Analysis of exposures pointed to a medical device used for storage and infusion of blood products, but no fungal contamination was detected in the unused devices. Molecular identification of isolates from previous studies demonstrated that S. clavata can be found in dairy products and has already been involved in monocentric outbreaks in hematology wards. The possibility that S. clavata may transmit through contaminated medical devices or can be associated with dairy products as seen in previous European outbreaks is highly relevant for the management of future outbreaks due to this newly recognized pathogen. This report also underlines further the potential of WGS for investigation of outbreaks due to uncommon fungal pathogens. Several cases of rapidly fatal infections due to the fungus Saprochaete clavata were reported in France within a short period of time in three health care facilities, suggesting a common source of contamination. A nationwide alert collected 30 cases over 1 year, including an outbreak of 18 cases over 8 weeks. Whole-genome sequencing (WGS) was used to analyze recent and historical isolates and to design a clade-specific genotyping method that uncovered a clone associated with the outbreak, thus allowing a case-case study to analyze the risk factors associated with infection by the clone. The possibility that S. clavata may transmit through contaminated medical devices or can be associated with dairy products as seen in previous European outbreaks is highly relevant for the management of future outbreaks due to this newly recognized pathogen. Copyright © 2014 Vaux et al.

Evaluation of Long-term Performance of Enhanced Anaerobic Source Zone Bioremediation using mass flux

NASA Astrophysics Data System (ADS)

Haluska, A.; Cho, J.; Hatzinger, P.; Annable, M. D.

2017-12-01

Chlorinated ethene DNAPL source zones in groundwater act as potential long term sources of contamination as they dissolve yielding concentrations well above MCLs, posing an on-going public health risk. Enhanced bioremediation has been applied to treat many source zones with significant promise, but long-term sustainability of this technology has not been thoroughly assessed. This study evaluated the long-term effectiveness of enhanced anaerobic source zone bioremediation at chloroethene contaminated sites to determine if the treatment prevented contaminant rebound and removed NAPL from the source zone. Long-term performance was evaluated based on achieving MCL-based contaminant mass fluxes in parent compound concentrations during different monitoring periods. Groundwater concertation versus time data was compiled for 6-sites and post-remedial contaminant mass flux data was then measured using passive flux meters at wells both within and down-gradient of the source zone. Post-remedial mass flux data was then combined with pre-remedial water quality data to estimate pre-remedial mass flux. This information was used to characterize a DNAPL dissolution source strength function, such as the Power Law Model and the Equilibrium Stream tube model. The six-sites characterized for this study were (1) Former Charleston Air Force Base, Charleston, SC; (2) Dover Air Force Base, Dover, DE; (3) Treasure Island Naval Station, San Francisco, CA; (4) Former Raritan Arsenal, Edison, NJ; (5) Naval Air Station, Jacksonville, FL; and, (6) Former Naval Air Station, Alameda, CA. Contaminant mass fluxes decreased for all the sites by the end of the post-treatment monitoring period and rebound was limited within the source zone. Post remedial source strength function estimates suggest that decreases in contaminant mass flux will continue to occur at these sites, but a mass flux based on MCL levels may never be exceeded. Thus, site clean-up goals should be evaluated as order-of-magnitude reductions. Additionally, sites may require monitoring for a minimum of 5-years in order to sufficiently evaluate remedial performance. The study shows that enhanced anaerobic source zone bioremediation contributed to a modest reduction of source zone contaminant mass discharge and appears to have mitigated rebound of chlorinated ethenes.

Contaminants and drinking-water sources in 2001; recent findings of the U. S. Geological Survey

USGS Publications Warehouse

Patterson, G.G.; Focazio, M.J.

2000-01-01

As the Nation's principal earth-science agency, the U.S. Geological Survey (USGS) studies numerous issues related to contamination of drinking-water sources. The work includes monitoring to determine the spatial and temporal distribution of contaminants; research to determine sources, transport, transformations, and fate of contaminants, and assessments of vulnerability. Much of the work is conducted in cooperation with the U.S. Environmental Protection Agency and other Federal, State, Tribal, and local governments, to help provide a scientific basis for resource management and regulation. Examples of recent results are presented for two broad categories of drinking-water projects: occurrence studies, and source-water assessments.

The effects of motorway runoff on freshwater ecosystems. 2: Identifying major toxicants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maltby, L.; Boxall, A.B.A.; Forrow, D.M.

1995-06-01

Previous studies have provided prima facie evidence that runoff from the M1 motorway, UK, affects both the quality of the receiving water and the biota living there, in sites short distances from point sources-i.e., possible worst-case situations. Because discharges contain a wide variety of contaminants, both the identification of toxicants and the establishment of causal relationships between observed changes in water/sediment quality and biology are often difficult. In this particular case, the problem was addressed by conducting a series of toxicity tests using the benthic amphipod Gammarus pulex. The abundance of this species was greatly reduced downstream of the pointmore » where motorway runoff entered the stream. Stream water contaminated with motorway runoff was not toxic to G. pulex. However, exposure to contaminated sediments resulted in a slight reduction in survival over 14 d, and sediment manipulation experiments identified hydrocarbons, copper, and zinc as potential toxicants. Spiking experiments confirmed the importance of hydrocarbons, and fractionation studies indicated that most of the observed toxicity was due to the fraction containing polycyclic aromatic hydrocarbons. Animals exposed to contaminated sediments and water spiked with sediment extract accumulated aromatic hydrocarbons in direct proportion to exposure concentrations.« less

Microbial communities along biogeochemical gradients in a hydrocarbon-contaminated aquifer.

PubMed

Tischer, Karolin; Kleinsteuber, Sabine; Schleinitz, Kathleen M; Fetzer, Ingo; Spott, Oliver; Stange, Florian; Lohse, Ute; Franz, Janett; Neumann, Franziska; Gerling, Sarah; Schmidt, Christian; Hasselwander, Eyk; Harms, Hauke; Wendeberg, Annelie

2013-09-01

Micro-organisms are known to degrade a wide range of toxic substances. How the environment shapes microbial communities in polluted ecosystems and thus influences degradation capabilities is not yet fully understood. In this study, we investigated microbial communities in a highly complex environment: the capillary fringe and subjacent sediments in a hydrocarbon-contaminated aquifer. Sixty sediment sections were analysed using terminal restriction fragment length polymorphism (T-RFLP) fingerprinting, cloning and sequencing of bacterial and archaeal 16S rRNA genes, complemented by chemical analyses of petroleum hydrocarbons, methane, oxygen and alternative terminal electron acceptors. Multivariate statistics revealed concentrations of contaminants and the position of the water table as significant factors shaping the microbial community composition. Micro-organisms with highest T-RFLP abundances were related to sulphate reducers belonging to the genus Desulfosporosinus, fermenting bacteria of the genera Sedimentibacter and Smithella, and aerobic hydrocarbon degraders of the genus Acidovorax. Furthermore, the acetoclastic methanogens Methanosaeta, and hydrogenotrophic methanogens Methanocella and Methanoregula were detected. Whereas sulphate and sulphate reducers prevail at the contamination source, the detection of methane, fermenting bacteria and methanogenic archaea further downstream points towards syntrophic hydrocarbon degradation. © 2013 John Wiley & Sons Ltd and Society for Applied Microbiology.

Geostatistics - a tool applied to the distribution of Legionella pneumophila in a hospital water system.

PubMed

Laganà, Pasqualina; Moscato, Umberto; Poscia, Andrea; La Milia, Daniele Ignazio; Boccia, Stefania; Avventuroso, Emanuela; Delia, Santi

2015-01-01

Legionnaires' disease is normally acquired by inhalation of legionellae from a contaminated environmental source. Water systems of large buildings, such as hospitals, are often contaminated with legionellae and therefore represent a potential risk for the hospital population. The aim of this study was to evaluate the potential contamination of Legionella pneumophila (LP) in a large hospital in Italy through georeferential statistical analysis to assess the possible sources of dispersion and, consequently, the risk of exposure for both health care staff and patients. LP serogroups 1 and 2-14 distribution was considered in the wards housed on two consecutive floors of the hospital building. On the basis of information provided by 53 bacteriological analysis, a 'random' grid of points was chosen and spatial geostatistics or FAIk Kriging was applied and compared with the results of classical statistical analysis. Over 50% of the examined samples were positive for Legionella pneumophila. LP 1 was isolated in 69% of samples from the ground floor and in 60% of sample from the first floor; LP 2-14 in 36% of sample from the ground floor and 24% from the first. The iso-estimation maps show clearly the most contaminated pipe and the difference in the diffusion of the different L. pneumophila serogroups. Experimental work has demonstrated that geostatistical methods applied to the microbiological analysis of water matrices allows a better modeling of the phenomenon under study, a greater potential for risk management and a greater choice of methods of prevention and environmental recovery to be put in place with respect to the classical statistical analysis.

Screening for Stockholm Convention persistent organic pollutants in the Bosna River (Bosnia and Herzogovina).

PubMed

Harman, Christopher; Grung, Merete; Djedjibegovic, Jasmina; Marjanovic, Aleksandra; Sober, Miroslav; Sinanovic, Kemo; Fjeld, Eirik; Rognerud, Sigurd; Ranneklev, Sissel Brit; Larssen, Thorjørn

2013-02-01

The Stockholm Convention, which aspires to manage persistent organic pollutants (POPs) at the international level, was recently ratified in Bosnia and Herzegovina (BiH). Despite this fact, there is in general a paucity of data regarding the levels of POPs in the environment in BiH. In the present study, screening for POPs was conducted in one of the country's major rivers, the Bosna. A two-pronged approach was applied using passive samplers to detect the freely dissolved and bioavailable concentrations in the water phase and sediment analysis to provide an integrated measure of historical contamination. At several places along the river, the concentrations of polycyclic aromatic hydrocarbons (PAH) were high and exhibited potential for both chronic and acute effects to biota. River water also showed elevated concentrations of PAH, up to 480 ng L(-1) near the city of Doboj, and diagnostic ratios suggested combustion sources for the contamination present in both types of sample. The levels of the other contaminants measured-polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and polybrominated diphenyl ethers--were generally low in the water phase. However, PCBs and some OCPs were present in river sediments at levels which breach the international criteria and thus suggest potential for ecological damage. Additionally, the levels of heptachlor breached these criteria in many of the sites investigated. This study presents the first screening data for some of these Stockholm Convention relevant compounds in BiH and reveals both low concentrations of some chemical groups, but significant point sources and historic contamination for others.

Integrated frameworks for assessing and managing health risks in the context of managed aquifer recharge with river water.

PubMed

Assmuth, Timo; Simola, Antti; Pitkänen, Tarja; Lyytimäki, Jari; Huttula, Timo

2016-01-01

Integrated assessment and management of water resources for the supply of potable water is increasingly important in light of projected water scarcity in many parts of the world. This article develops frameworks for regional-level waterborne human health risk assessment of chemical and microbiological contamination to aid water management, incorporating economic aspects of health risks. Managed aquifer recharge with surface water from a river in Southern Finland is used as an illustrative case. With a starting point in watershed governance, stakeholder concerns, and value-at-risk concepts, we merge common methods for integrative health risk analysis of contaminants to describe risks and impacts dynamically and broadly. This involves structuring analyses along the risk chain: sources-releases-environmental transport and fate-exposures-health effects-socio-economic impacts-management responses. Risks attributed to contaminants are embedded in other risks, such as contaminants from other sources, and related to benefits from improved water quality. A set of models along this risk chain in the case is presented. Fundamental issues in the assessment are identified, including 1) framing of risks, scenarios, and choices; 2) interaction of models and empirical information; 3) time dimension; 4) distributions of risks and benefits; and 5) uncertainties about risks and controls. We find that all these combine objective and subjective aspects, and involve value judgments and policy choices. We conclude with proposals for overcoming conceptual and functional divides and lock-ins to improve modeling, assessment, and management of complex water supply schemes, especially by reflective solution-oriented interdisciplinary and multi-actor deliberation. © 2015 SETAC.

A stable isotope approach for source apportionment of chlorinated ethene plumes at a complex multi-contamination events urban site

NASA Astrophysics Data System (ADS)

Nijenhuis, Ivonne; Schmidt, Marie; Pellegatti, Eleonora; Paramatti, Enrico; Richnow, Hans Hermann; Gargini, Alessandro

2013-10-01

The stable carbon isotope composition of chlorinated aliphatic compounds such as chlorinated methanes, ethanes and ethenes was examined as an intrinsic fingerprint for apportionment of sources. A complex field site located in Ferrara (Italy), with more than 50 years history of use of chlorinated aliphatic compounds, was investigated in order to assess contamination sources. Several contamination plumes were found in a complex alluvial sandy multi-aquifer system close to the river Po; sources are represented by uncontained former industrial and municipal dump sites as well as by spills at industrial areas. The carbon stable isotope signature allowed distinguishing 2 major sources of contaminants. One source of chlorinated aliphatic contaminants was strongly depleted in 13C (<-60‰) suggesting production lines which have used depleted methane for synthesis. The other source had typical carbon isotope compositions of >-40‰ which is commonly observed in recent production of chlorinated solvents. The degradation processes in the plumes could be traced interpreting the isotope enrichment and depletion of parent and daughter compounds, respectively. We demonstrate that, under specific production conditions, namely when highly chlorinated ethenes are produced as by-product during chloromethanes production, 13C depleted fingerprinting of contaminants can be obtained and this can be used to track sources and address the responsible party of the pollution in urban areas.

A stable isotope approach for source apportionment of chlorinated ethene plumes at a complex multi-contamination events urban site.

PubMed

Nijenhuis, Ivonne; Schmidt, Marie; Pellegatti, Eleonora; Paramatti, Enrico; Richnow, Hans Hermann; Gargini, Alessandro

2013-10-01

The stable carbon isotope composition of chlorinated aliphatic compounds such as chlorinated methanes, ethanes and ethenes was examined as an intrinsic fingerprint for apportionment of sources. A complex field site located in Ferrara (Italy), with more than 50years history of use of chlorinated aliphatic compounds, was investigated in order to assess contamination sources. Several contamination plumes were found in a complex alluvial sandy multi-aquifer system close to the river Po; sources are represented by uncontained former industrial and municipal dump sites as well as by spills at industrial areas. The carbon stable isotope signature allowed distinguishing 2 major sources of contaminants. One source of chlorinated aliphatic contaminants was strongly depleted in ¹³C (<-60‰) suggesting production lines which have used depleted methane for synthesis. The other source had typical carbon isotope compositions of >-40‰ which is commonly observed in recent production of chlorinated solvents. The degradation processes in the plumes could be traced interpreting the isotope enrichment and depletion of parent and daughter compounds, respectively. We demonstrate that, under specific production conditions, namely when highly chlorinated ethenes are produced as by-product during chloromethanes production, ¹³C depleted fingerprinting of contaminants can be obtained and this can be used to track sources and address the responsible party of the pollution in urban areas. © 2013 Elsevier B.V. All rights reserved.

Field based plastic contamination sensing

USDA-ARS?s Scientific Manuscript database

The United States has a long-held reputation of being a dependable source of high quality, contaminant-free cotton. Recently, increased incidence of plastic contamination from sources such as shopping bags, vegetable mulch, surface irrigation tubing, and module covers has threatened the reputation o...

DEVELOPMENT OF A DATA EVALUATION/DECISION SUPPORT SYSTEM FOR REMEDIATION OF SUBSURFACE CONTAMINATION

EPA Science Inventory

Subsurface contamination frequently originates from spatially distributed sources of multi-component nonaqueous phase liquids (NAPLs). Such chemicals are typically persistent sources of ground-water contamination that are difficult to characterize. This work addresses the feasi...

PRIORITIZATION OF GROUND WATER CONTAMINANTS AND SOURCES

EPA Science Inventory

The objective of this research was to identify chemical, physical, bacteriological, and viral contaminants, and their sources, which present the greatest health threat in public ground water supplies in the USA; and to classify (prioritize) such contaminants and relative to their...

Deriving realistic source boundary conditions for a CFD simulation of concentrations in workroom air.

PubMed

Feigley, Charles E; Do, Thanh H; Khan, Jamil; Lee, Emily; Schnaufer, Nicholas D; Salzberg, Deborah C

2011-05-01

Computational fluid dynamics (CFD) is used increasingly to simulate the distribution of airborne contaminants in enclosed spaces for exposure assessment and control, but the importance of realistic boundary conditions is often not fully appreciated. In a workroom for manufacturing capacitors, full-shift samples for isoamyl acetate (IAA) were collected for 3 days at 16 locations, and velocities were measured at supply grills and at various points near the source. Then, velocity and concentration fields were simulated by 3-dimensional steady-state CFD using 295K tetrahedral cells, the k-ε turbulence model, standard wall function, and convergence criteria of 10(-6) for all scalars. Here, we demonstrate the need to represent boundary conditions accurately, especially emission characteristics at the contaminant source, and to obtain good agreement between observations and CFD results. Emission rates for each day were determined from six concentrations measured in the near field and one upwind using an IAA mass balance. The emission was initially represented as undiluted IAA vapor, but the concentrations estimated using CFD differed greatly from the measured concentrations. A second set of simulations was performed using the same IAA emission rates but a more realistic representation of the source. This yielded good agreement with measured values. Paying particular attention to the region with highest worker exposure potential-within 1.3 m of the source center-the air speed and IAA concentrations estimated by CFD were not significantly different from the measured values (P = 0.92 and P = 0.67, respectively). Thus, careful consideration of source boundary conditions greatly improved agreement with the measured values.

Stanols as a tool to track the origin of microbial contamination of oysters, Crassostrea gigas, in shellfish areas.

NASA Astrophysics Data System (ADS)

Harrault, Loïc; Jardé, Emilie; Jeanneau, Laurent; Petitjean, Patrice

2013-04-01

Runoff of cattle manures (cows, pigs, sheeps) or discharge of effluent from wastewater treatment plants (WWTP) into aquatic ecosystems can lead to microbiological contamination of waters and living organisms. In coastal ecosystems and particularly in shellfish harvesting areas, the presence of pathogen microorganisms in waters induces fecal contamination of filter feeding bivalves (oysters, mussels, scallops…), therefore leading to human health risks associated to the consumption of these contaminated organisms. Watershed management plans that aim at limiting these risks require the development of tools able to identify fecal contamination sources. The fecal indicator bacteria used in the regulations to determine fecal contamination are not source specific since they are found in the feces of most warm-blooded animals. Thus, microbiological biomarkers have been developed in association with chemical biomarkers as Microbial Source Tracking (MST) methods. Fecal stanols, by-products of sterols obtained by human and animal microbial gut flora, are found in considerable amounts in feces with different relative proportions depending on their animal or human source. Recently, in association with microbiological biomarkers, the stanol fingerprint of contaminated waters has been successfully used to determine the main source of fecal contamination (cow, pig or human sources) in rural watersheds (Brittany, France). Up to now, the use of the stanol fingerprint to track the fecal contamination in shellfish tissues, especially bivalves, has been limited to the analysis of coprostanol, a stanol commonly associated to human contamination. Therefore, whether the stanol fingerprint can be used as a MST method in bivalves or not is still unknown. The first aim of this study was to compare several organic extraction procedures of stanols in the oyster Crassostrea gigas to determine a reliable method for stanol fingerprint analysis in bivalves. Solvent extraction and purification steps have been carried out with attention as they are critical for stanol quantification. Secondly, the evolution of the stanol fingerprint of oysters with time was evaluated during 6 days by artificially contaminating microcosms with two concentrations of a WWTP effluent. In the microcosms, the fingerprint of stanols as a chemical biomarkers of fecal (human) contamination was compared to counts of Escherichia coli, a commonly used microbial indicator. In association with microbial markers, the method developed from the two previous steps will be applied at the watershed scale in order to identify sources of fecal contamination in Brittany and Normandy (France).

Distributional patterns of arsenic concentrations in contaminant plumes offer clues to the source of arsenic in groundwater at landfills

USGS Publications Warehouse

Harte, Philip T.

2015-01-01

The distributional pattern of dissolved arsenic concentrations from landfill plumes can provide clues to the source of arsenic contamination. Under simple idealized conditions, arsenic concentrations along flow paths in aquifers proximal to a landfill will decrease under anthropogenic sources but potentially increase under in situ sources. This paper presents several conceptual distributional patterns of arsenic in groundwater based on the arsenic source under idealized conditions. An example of advanced subsurface mapping of dissolved arsenic with geophysical surveys, chemical monitoring, and redox fingerprinting is presented for a landfill site in New Hampshire with a complex flow pattern. Tools to assist in the mapping of arsenic in groundwater ultimately provide information on the source of contamination. Once an understanding of the arsenic contamination is achieved, appropriate remedial strategies can then be formulated.

A Deep XMM-Newton Survey of M33: Point-source Catalog, Source Detection, and Characterization of Overlapping Fields

NASA Astrophysics Data System (ADS)

Williams, Benjamin F.; Wold, Brian; Haberl, Frank; Garofali, Kristen; Blair, William P.; Gaetz, Terrance J.; Kuntz, K. D.; Long, Knox S.; Pannuti, Thomas G.; Pietsch, Wolfgang; Plucinsky, Paul P.; Winkler, P. Frank

2015-05-01

We have obtained a deep 8 field XMM-Newton mosaic of M33 covering the galaxy out to the D25 isophote and beyond to a limiting 0.2-4.5 keV unabsorbed flux of 5 × 10-16 erg cm-2 s-1 (L \\gt 4 × 1034 erg s-1 at the distance of M33). These data allow complete coverage of the galaxy with high sensitivity to soft sources such as diffuse hot gas and supernova remnants (SNRs). Here, we describe the methods we used to identify and characterize 1296 point sources in the 8 fields. We compare our resulting source catalog to the literature, note variable sources, construct hardness ratios, classify soft sources, analyze the source density profile, and measure the X-ray luminosity function (XLF). As a result of the large effective area of XMM-Newton below 1 keV, the survey contains many new soft X-ray sources. The radial source density profile and XLF for the sources suggest that only ˜15% of the 391 bright sources with L \\gt 3.6 × 1035 erg s-1 are likely to be associated with M33, and more than a third of these are known SNRs. The log(N)-log(S) distribution, when corrected for background contamination, is a relatively flat power law with a differential index of 1.5, which suggests that many of the other M33 sources may be high-mass X-ray binaries. Finally, we note the discovery of an interesting new transient X-ray source, which we are unable to classify.

Sources of nitrate in the Arno River waters: Constraints from d15N and d18O

USGS Publications Warehouse

Nisi, Barbara; Vaselli, Orlando; Buccianti, Antonella; Silva, Steven R.

2005-01-01

Running waters in anthropogenically affected areas are susceptible to nitrate contamination. Source identification is a fundamental step for the development of effective remediation. Previous studies pointed to pollution by nitrogen-bearing contaminants in the Arno Basin. In this paper, eleven surface water samples have been analysed for main and trace components and 15N/14N and 18O/16O ratios, with the aim of identifying for the first time the origin of nitrate in the Arno River Basin so that further investigations can appropriately be designed. d18O(NO3)and d15N(NO3) values have allowed to hypothesise the main sources of nitrate, as follows: i) mineralized fertilizer, ii) soil-organic nitrogen, iii) manure and septic waste. The anomalously high d15N and d18O values in the Chiana (d15N=24.9‰ and d18O=15.5‰) and Usciana tributaries (d15N=30.1‰ and d18O=7.2‰) show a low probability of belonging to the same population as that of the other samples and can be related to denitrification process of nitrate from animal waste/sewage and/or an industrial process (e.g. tanneries).

Monitoring bacterial contamination of piped water supply in rural coastal Bangladesh.

PubMed

Ahsan, Md Sabbir; Akber, Md Ali; Islam, Md Atikul; Kabir, Md Pervez; Hoque, Md Ikramul

2017-10-31

Safe drinking water is scarce in southwest coastal Bangladesh because of unavailability of fresh water. Given the high salinity of both groundwater and surface water in this area, harvested rainwater and rain-fed pond water became the main sources of drinking water. Both the government and non-government organizations have recently introduced pipe water supply in the rural coastal areas to ensure safe drinking water. We assessed the bacteriological quality of water at different points along the piped water distribution system (i.e., the source, treatment plant, household taps, street hydrants, and household storage containers) of Mongla municipality under Mongla Upazila in Bagerhat district. Water samples were collected at 2-month interval from May 2014 to March 2015. Median E. coli and total coliform counts at source, treatment plant, household taps, street hydrants, and household storage containers were respectively 225, 4, 7, 7, and 15 cfu/100 ml and 42,000, 545, 5000, 6150, and 18,800 cfu/100 ml. Concentrations of both of the indicator bacteria reduced after treatment, although it did not satisfy the WHO drinking water standards. However, re-contamination in distribution systems and household storage containers indicate improper maintenance of distribution system and lack of personal hygiene.

Nitrate variability in groundwater of North Carolina using monitoring and private well data models.

PubMed

Messier, Kyle P; Kane, Evan; Bolich, Rick; Serre, Marc L

2014-09-16

Nitrate (NO3-) is a widespread contaminant of groundwater and surface water across the United States that has deleterious effects to human and ecological health. This study develops a model for predicting point-level groundwater NO3- at a state scale for monitoring wells and private wells of North Carolina. A land use regression (LUR) model selection procedure is developed for determining nonlinear model explanatory variables when they are known to be correlated. Bayesian Maximum Entropy (BME) is used to integrate the LUR model to create a LUR-BME model of spatial/temporal varying groundwater NO3- concentrations. LUR-BME results in a leave-one-out cross-validation r2 of 0.74 and 0.33 for monitoring and private wells, effectively predicting within spatial covariance ranges. Results show significant differences in the spatial distribution of groundwater NO3- contamination in monitoring versus private wells; high NO3- concentrations in the southeastern plains of North Carolina; and wastewater treatment residuals and swine confined animal feeding operations as local sources of NO3- in monitoring wells. Results are of interest to agencies that regulate drinking water sources or monitor health outcomes from ingestion of drinking water. Lastly, LUR-BME model estimates can be integrated into surface water models for more accurate management of nonpoint sources of nitrogen.

When enough is enough: The worth of monitoring data in aquifer remediation design

NASA Astrophysics Data System (ADS)

James, Bruce R.; Gorelick, Steven M.

1994-12-01

Given the high cost of data collection at groundwater contamination remediation sites, it is becoming increasingly important to make data collection as cost-effective as possible. A Bayesian data worth framework is developed in an attempt to carry out this task for remediation programs in which a groundwater contaminant plume must be located and then hydraulically contained. The framework is applied to a hypothetical contamination problem where uncertainty in plume location and extent are caused by uncertainty in source location, source loading time, and aquifer heterogeneity. The goal is to find the optimum number and the best locations for a sequence of observation wells that minimize the expected cost of remediation plus sampling. Simplifying assumptions include steady state heads, advective transport, simple retardation, and remediation costs as a linear function of discharge rate. In the case here, an average of six observation wells was needed. Results indicate that this optimum number was particularly sensitive to the mean hydraulic conductivity. The optimum number was also sensitive to the variance of the hydraulic conductivity, annual discount rate, operating cost, and sample unit cost. It was relatively insensitive to the correlation length of hydraulic conductivity. For the case here, points of greatest uncertainty in plume presence were on average poor candidates for sample locations, and randomly located samples were not cost-effective.

Levels and potential sources of decabromodiphenyl ethane (DBDPE) and decabromodiphenyl ether (DecaBDE) in lake and marine sediments in Sweden.

PubMed

Ricklund, Niklas; Kierkegaard, Amelie; McLachlan, Michael S

2010-03-15

Decabromodiphenyl ethane (DBDPE) is a brominated flame retardant (BFR) used as a replacement for the structurally similar decabromodiphenyl ether (decaBDE), which is a regulated environmental contaminant of concern. DBDPE has been found in indoor dust, sewage sludge, sediment, and biota, but little is known about its occurrence and distribution in the environment In this paper, sediment was analyzed from 11 isolated Swedish lakes and along a transect running from central Stockholm through the Stockholm archipelago to the Baltic Sea. DBDPE was present in all samples. In lake sediment, the levels ranged from 0.23 to 11 ng/g d.wt. and were very similar to the levels of decaBDE (0.48-11 ng/g d.wt.). Since the lakes have no known point sources of BFRs, their presence in the sediments provides evidence for long-range atmospheric transport and deposition. In the marine sediment, the DBDPE and decaBDE levels decreased by a factor of 20-50 over 40 km from the inner harbor to the outer archipelago. There the DBDPE and decaBDE levels were similar to the levels in nearby isolated lakes. The results indicate that contamination of the Swedish environment with DBDPE has already approached that of decaBDE, and that this contamination is primarily occurring via the atmosphere.

Circumstances associated with the contamination of food by aflatoxin in a high primary liver cancer area.

PubMed

Van Rensburg, S J; Kirsipuu, A; Coutinho, L P; Van Der Watt, J J

1975-05-24

The variable incidence of primary liver cancer has been shown to be related to the average daily intake of aflatoxin in various parts of the world. This study was made to detect and report strategic points of contamination of foodstuffs in the region with the highest known incidence of liver cancer. Methods of food production, harvesting, storage and preparation were examined, and defects which promote fungus growth on food were found at each stage. Most meals consisted of a single dish with three basic ingredients -- a protein, bulk carbohydrate and green vegetables. Groundnuts were the main source of protein, but were also the main cause of aflatoxin contamination, since casual traditional methods of agriculture are not suited to the production of this exotic crop. Aflatoxin production appears to occur in the main sources of carbohydrate, such as cassava and maize, during storage. Leaves of various kinds provide substitutes for green vegetables and common methods of handling the crop promote fungal growth. Western-type foods had a particularly low aflatoxin content, or were free of it. Education and economic opportunities external to the subsistence economy structure are contributing to the westerisation of some living habits, a process believed to be responsible for the observed decrease in the incidence of primary liver cancer. Current knowledge indicates that a pertinent but simple educational programme could further markedly reduce the incidence of the disease.

UV filters, ethylhexyl methoxycinnamate, octocrylene and ethylhexyl dimethyl PABA from untreated wastewater in sediment from eastern Mediterranean river transition and coastal zones.

PubMed

Amine, Helmieh; Gomez, Elena; Halwani, Jalal; Casellas, Claude; Fenet, Hélène

2012-11-01

UVF may occur in the aquatic environment through two principal sources: direct inputs from recreational activities and indirect wastewater- and river-borne inputs. The aim of this study was to obtain a first overview of levels of three UVF (EHMC, OC and OD-PABA) in coastal areas subjected to river inputs, untreated wastewater discharges and dumpsite leachates. We selected three eastern Mediterranean rivers that have been impacted for decades by untreated wastewater release and collected sediment in the coastal zone during the hot and humid seasons. Western Mediterranean sites receiving treated wastewaters were analyzed for comparison. The results gave an overview of sediment contamination under these two contrasted situations representative of Mediterranean coastal areas without bathing activities. The analysis of the three UVF revealed the ubiquity and high point source contamination by EHMC and OC in transition and coastal zones, with levels as high as 128 ng g(-1)d.w. OD-PABA was also frequently detected, but at lower concentrations (

Modeled occupational exposures to gas-phase medical laser-generated air contaminants.

PubMed

Lippert, Julia F; Lacey, Steven E; Jones, Rachael M

2014-01-01

Exposure monitoring data indicate the potential for substantive exposure to laser-generated air contaminants (LGAC); however the diversity of medical lasers and their applications limit generalization from direct workplace monitoring. Emission rates of seven previously reported gas-phase constituents of medical laser-generated air contaminants (LGAC) were determined experimentally and used in a semi-empirical two-zone model to estimate a range of plausible occupational exposures to health care staff. Single-source emission rates were generated in an emission chamber as a one-compartment mass balance model at steady-state. Clinical facility parameters such as room size and ventilation rate were based on standard ventilation and environmental conditions required for a laser surgical facility in compliance with regulatory agencies. All input variables in the model including point source emission rates were varied over an appropriate distribution in a Monte Carlo simulation to generate a range of time-weighted average (TWA) concentrations in the near and far field zones of the room in a conservative approach inclusive of all contributing factors to inform future predictive models. The concentrations were assessed for risk and the highest values were shown to be at least three orders of magnitude lower than the relevant occupational exposure limits (OELs). Estimated values do not appear to present a significant exposure hazard within the conditions of our emission rate estimates.

A Nondestructive Method to Identify POP Contamination Sources in Omnivorous Seabirds.

PubMed

Michielsen, Rosanne J; Shamoun-Baranes, Judy; Parsons, John R; Kraak, Michiel H S

2018-03-13

Persistent organic pollutants (POPs) are present in almost all environments due to their high bioaccumulation potential. Especially species that adapted to human activities, like gulls, might be exposed to harmful concentrations of these chemicals. The nature and degree of the exposure to POPs greatly vary between individual gulls, due to their diverse foraging behavior and specialization in certain foraging tactics. Therefore, in order clarify the effect of POP-contaminated areas on gull populations, it is important to identify the sources of POP contamination in individual gulls. Conventional sampling methods applied when studying POP contamination are destructive and ethically undesired. The aim of this literature review was to evaluate the potential of using feathers as a nondestructive method to determine sources of POP contamination in individual gulls. The reviewed data showed that high concentrations of PCBs and PBDEs in feathers together with a large proportion of less bioaccumulative congeners may indicate that the contamination originates from landfills. Low PCB and PBDE concentrations in feathers and a large proportion of more bioaccumulative congeners could indicate that the contamination originates from marine prey. We propose a nondestructive approach to identify the source of contamination in individual gulls based on individual contamination levels and PCB and PBDE congener profiles in feathers. Despite some uncertainties that might be reduced by future research, we conclude that especially when integrated with other methods like GPS tracking and the analysis of stable isotopic signatures, identifying the source of POP contamination based on congener profiles in feathers could become a powerful nondestructive method.

Assessment of the potential of the rock gunnel (Pholis gunnellus) along the Atlantic coast of Canada as a species for monitoring the reproductive impacts of contaminant exposures.

PubMed

Vallis, L; MacLatchy, D L; Munkittrick, K R

2007-05-01

Evaluating the impacts of point source discharges on fish species in estuarine environments can be challenging because of a paucity of resident species. We evaluated the biology of rock gunnel (Pholis gunnellus) at three relatively uncontaminated sites in the Bay of Fundy, along the Atlantic coast of Canada. Rock gunnel are seasonally resident (April to November) in tide pools, but little was known about their life history in Atlantic Canada or their potential for use for monitoring environmental quality. Fish were collected between April and November, and ranged from 2.46 g-15.2g in weight and 97 mm-170 mm in length, with a maximum age of 7 years. Both males and females were similar in size, and both reached sexual maturity at a size of 5.5 g. Organ weights and condition indices of fish were stable from spring when they returned from offshore (April to May) until late summer (August to September), but fall fish (October to November) had slightly larger gonads, livers and condition indices. Rock gunnel may be a useful indicator to provide insight into local impacts of point sources over a short time period. However, they do not provide adequate information on reproductive development and performance since they are not exposed to onshore contaminants during the periods of gonadal development that have most commonly found to be sensitive to anthropogenic stressors.

THE IMPACT OF PARTIAL DNAPL SOURCE ZONE REMEDIATION

EPA Science Inventory

Dense non-aqueous phase liquids (DNAPL) constitute a long-term source of groundwater contamination and a significant effort is usually required to treat these contaminated waters and bring them back to maximum contaminant level (MCL) required by the regulatory authorities.
Fi...

Molecular Microbial Ecology of a Full-Scale Biologically Active Filter

EPA Science Inventory

Drinking water utilities are challenged with a variety of contamination issues both from the source water and in the distribution system. Source water issues include inorganic contaminants such as arsenic, barium, iron, and biological contaminants such as bacteria and viruses. ...

Characterization and Remediation of Contaminated Sites:Modeling, Measurement and Assessment

NASA Astrophysics Data System (ADS)

Basu, N. B.; Rao, P. C.; Poyer, I. C.; Christ, J. A.; Zhang, C. Y.; Jawitz, J. W.; Werth, C. J.; Annable, M. D.; Hatfield, K.

2008-05-01

The complexity of natural systems makes it impossible to estimate parameters at the required level of spatial and temporal detail. Thus, it becomes necessary to transition from spatially distributed parameters to spatially integrated parameters that are capable of adequately capturing the system dynamics, without always accounting for local process behavior. Contaminant flux across the source control plane is proposed as an integrated metric that captures source behavior and links it to plume dynamics. Contaminant fluxes were measured using an innovative technology, the passive flux meter at field sites contaminated with dense non-aqueous phase liquids or DNAPLs in the US and Australia. Flux distributions were observed to be positively or negatively correlated with the conductivity distribution, depending on the source characteristics of the site. The impact of partial source depletion on the mean contaminant flux and flux architecture was investigated in three-dimensional complex heterogeneous settings using the multiphase transport code UTCHEM and the reactive transport code ISCO3D. Source mass depletion reduced the mean contaminant flux approximately linearly, while the contaminant flux standard deviation reduced proportionally with the mean (i.e., coefficient of variation of flux distribution is constant with time). Similar analysis was performed using data from field sites, and the results confirmed the numerical simulations. The linearity of the mass depletion-flux reduction relationship indicates the ability to design remediation systems that deplete mass to achieve target reduction in source strength. Stability of the flux distribution indicates the ability to characterize the distributions in time once the initial distribution is known. Lagrangian techniques were used to predict contaminant flux behavior during source depletion in terms of the statistics of the hydrodynamic and DNAPL distribution. The advantage of the Lagrangian techniques lies in their small computation time and their inclusion of spatially integrated parameters that can be measured in the field using tracer tests. Analytical models that couple source depletion to plume transport were used for optimization of source and plume treatment. These models are being used for the development of decision and management tools (for DNAPL sites) that consider uncertainty assessments as an integral part of the decision-making process for contaminated site remediation.

Source water assessment and nonpoint sources of acutely toxic contaminants: A review of research related to survival and transport of Cryptosporidium parvum

NASA Astrophysics Data System (ADS)

Walker, Mark J.; Montemagno, Carlo D.; Jenkins, Michael B.

1998-12-01

Amendments to the Safe Drinking Water Act (PL-930123) in 1996 required that public water supply managers identify potential sources of contamination within contributing areas. Nonpoint sources of acutely toxic microbial contaminants, such as Cryptosporidium parvum, challenge current approaches to source identification and management as a first step toward developing management plans for public water supply protection. Little may be known about survival and transport in the field environment, prescribed practices may not be designed to manage such substances, and infective stages may be present in vast numbers and may resist water treatment and disinfection processes. This review summarizes research related to survival and transport of C. parvum oocysts, as an example of an acutely toxic contaminant with nonpoint sources in animal agriculture. It discusses ∥1) significance of infected domesticated animals as potential sources of C. parvum, (2) laboratory and field studies of survival and transport, and (3) approaches to source control in the context of public health protection.

Continuous monitoring of water flow and solute transport using vadose zone monitoring technology

NASA Astrophysics Data System (ADS)

Dahan, O.

2009-04-01

Groundwater contamination is usually attributed to pollution events that initiate on land surface. These may be related to various sources such as industrial, urban or agricultural, and may appear as point or non point sources, through a single accidental event or a continuous pollution process. In all cases, groundwater pollution is a consequence of pollutant transport processes that take place in the vadose zone above the water table. Attempts to control pollution events and prevent groundwater contamination usually involve groundwater monitoring programs. This, however, can not provide any protection against contamination since pollution identification in groundwater is clear evidence that the groundwater is already polluted and contaminants have already traversed the entire vadose zone. Accordingly, an efficient monitoring program that aims at providing information that may prevent groundwater pollution has to include vadose-zone monitoring systems. Such system should provide real-time information on the hydrological and chemical properties of the percolating water and serve as an early warning system capable of detecting pollution events in their early stages before arrival of contaminants to groundwater. Recently, a vadose-zone monitoring system (VMS) was developed to allow continuous monitoring of the hydrological and chemical properties of percolating water in the deep vadose zone. The VMS includes flexible time-domain reflectometry (FTDR) probes for continuous tracking of water content profiles, and vadose-zone sampling ports (VSPs) for frequent sampling of the deep vadose pore water at multiple depths. The monitoring probes and sampling ports are installed through uncased slanted boreholes using a flexible sleeve that allows attachment of the monitoring devices to the borehole walls while achieving good contact between the sensors and the undisturbed sediment column. The system has been successfully implemented in several studies on water flow and contaminant transport in various hydrological and geological setups. These include floodwater infiltration in arid environments, land use impact on groundwater quality, and control of remediation process in a contaminated vadose zone. The data which is collected by the VMS allows direct measurements of flow velocities and fluxes in the vadose zone while continuously monitoring the chemical evolution of the percolating water. While real time information on the hydrological and chemical properties of the percolating water in the vadose is essential to prevent groundwater contamination it is also vital for any remediation actions. Remediation of polluted soils and aquifers essentially involves manipulation of surface and subsurface hydrological, physical and biochemical conditions to improve pollutant attenuation. Controlling the biochemical conditions to enhance biodegradation often includes introducing degrading microorganisms, applying electron donors or acceptors, or adding nutrients that can promote growth of the desired degrading organisms. Accordingly real time data on the hydrological and chemical properties of the vadose zone may be used to select remediation strategies and determine its efficiency on the basis of real time information.

A mass balance approach to investigate arsenic cycling in a petroleum plume.

PubMed

Ziegler, Brady A; Schreiber, Madeline E; Cozzarelli, Isabelle M; Crystal Ng, G-H

2017-12-01

Natural attenuation of organic contaminants in groundwater can give rise to a series of complex biogeochemical reactions that release secondary contaminants to groundwater. In a crude oil contaminated aquifer, biodegradation of petroleum hydrocarbons is coupled with the reduction of ferric iron (Fe(III)) hydroxides in aquifer sediments. As a result, naturally occurring arsenic (As) adsorbed to Fe(III) hydroxides in the aquifer sediment is mobilized from sediment into groundwater. However, Fe(III) in sediment of other zones of the aquifer has the capacity to attenuate dissolved As via resorption. In order to better evaluate how long-term biodegradation coupled with Fe-reduction and As mobilization can redistribute As mass in contaminated aquifer, we quantified mass partitioning of Fe and As in the aquifer based on field observation data. Results show that Fe and As are spatially correlated in both groundwater and aquifer sediments. Mass partitioning calculations demonstrate that 99.9% of Fe and 99.5% of As are associated with aquifer sediment. The sediments act as both sources and sinks for As, depending on the redox conditions in the aquifer. Calculations reveal that at least 78% of the original As in sediment near the oil has been mobilized into groundwater over the 35-year lifespan of the plume. However, the calculations also show that only a small percentage of As (∼0.5%) remains in groundwater, due to resorption onto sediment. At the leading edge of the plume, where groundwater is suboxic, sediments sequester Fe and As, causing As to accumulate to concentrations 5.6 times greater than background concentrations. Current As sinks can serve as future sources of As as the plume evolves over time. The mass balance approach used in this study can be applied to As cycling in other aquifers where groundwater As results from biodegradation of an organic carbon point source coupled with Fe reduction. Copyright © 2017 Elsevier Ltd. All rights reserved.

A mass balance approach to investigate arsenic cycling in a petroleum plume

USGS Publications Warehouse

Ziegler, Brady A.; Schreiber, Madeline E.; Cozzarelli, Isabelle M.; Ng. G.-H. Crystal,

2017-01-01

Natural attenuation of organic contaminants in groundwater can give rise to a series of complex biogeochemical reactions that release secondary contaminants to groundwater. In a crude oil contaminated aquifer, biodegradation of petroleum hydrocarbons is coupled with the reduction of ferric iron (Fe(III)) hydroxides in aquifer sediments. As a result, naturally occurring arsenic (As) adsorbed to Fe(III) hydroxides in the aquifer sediment is mobilized from sediment into groundwater. However, Fe(III) in sediment of other zones of the aquifer has the capacity to attenuate dissolved As via resorption. In order to better evaluate how long-term biodegradation coupled with Fe-reduction and As mobilization can redistribute As mass in contaminated aquifer, we quantified mass partitioning of Fe and As in the aquifer based on field observation data. Results show that Fe and As are spatially correlated in both groundwater and aquifer sediments. Mass partitioning calculations demonstrate that 99.9% of Fe and 99.5% of As are associated with aquifer sediment. The sediments act as both sources and sinks for As, depending on the redox conditions in the aquifer. Calculations reveal that at least 78% of the original As in sediment near the oil has been mobilized into groundwater over the 35-year lifespan of the plume. However, the calculations also show that only a small percentage of As (∼0.5%) remains in groundwater, due to resorption onto sediment. At the leading edge of the plume, where groundwater is suboxic, sediments sequester Fe and As, causing As to accumulate to concentrations 5.6 times greater than background concentrations. Current As sinks can serve as future sources of As as the plume evolves over time. The mass balance approach used in this study can be applied to As cycling in other aquifers where groundwater As results from biodegradation of an organic carbon point source coupled with Fe reduction.

Characterization of ecological risks at the Milltown Reservoir-Clark Fork River Sediments Superfund Site, Montana

USGS Publications Warehouse

Pascoe, Gary A.; Blanchet, Richard J.; Linder, Greg L.; Palawski, Don; Brumbaugh, William G.; Canfield, Tim J.; Kemble, Nile E.; Ingersoll, Chris G.; Farag, Aïda M.; DalSoglio, Julie A.

1994-01-01

A comprehensive field and laboratory approach to the ecological risk assessment for the Milltown Reservoir-Clark Fork River Sediments Site, a Superfund site in the Rocky Mountains of Montana, has been described in the preceding reports of this series. The risk assessment addresses concerns over the ecological impacts of upstream releases of mining wastes to fisheries of the upper Clark Fork River (CFR) and the benthic and terrestrial habitats further downstream in Milltown Reservoir. The risk characterization component of the process integrated results from a triad of information sources: (a) chemistry studies of environmental media to identify and quantify exposures of terrestrial and aquatic organisms to site-related contaminants; (b) ecological or population studies of terrestrial vegetation, birds, benthic communities, and fish; and (c) in situ and laboratory toxicity studies with terrestrial and aquatic invertebrates and plants, small mammals, amphibians, and fish exposed to contaminated surface water, sediments, wetland soils, and food sources. Trophic transfer studies were performed on waterfowl, mammals, and predatory birds using field measurement data on metals concentrations in environmental media and lower trophic food sources. Studies with sediment exposures were incorporated into the Sediment Quality Triad approach to evaluate risks to benthic ecology. Overall results of the wetland and terrestrial studies suggested that acute adverse biological effects were largely absent from the wetland; however, adverse effects to reproductive, growth, and physiological end points of various terrestrial and aquatic species were related to metals exposures in more highly contaminated depositional areas. Feeding studies with contaminated diet collected from the upper CFR indicated that trout are at high risk from elevated metals concentrations in surface water, sediment, and aquatic invertebrates. Integration of chemical analyses with toxicological and ecological evaluations of metal effects on the wetland and fishery has provided an important foundation for environmental decisions at this site.

Bayesian modeling approach for characterizing groundwater arsenic contamination in the Mekong River basin.

PubMed

Cha, YoonKyung; Kim, Young Mo; Choi, Jae-Woo; Sthiannopkao, Suthipong; Cho, Kyung Hwa

2016-01-01

In the Mekong River basin, groundwater from tube-wells is a major drinking water source. However, arsenic (As) contamination in groundwater resources has become a critical issue in the watershed. In this study, As species such as total As (AsTOT), As(III), and As(V), were monitored across the watershed to investigate their characteristics and inter-relationships with water quality parameters, including pH and redox potential (Eh). The data illustrated a dramatic change in the relationship between AsTOT and Eh over a specific Eh range, suggesting the importance of Eh in predicting AsTOT. Thus, a Bayesian change-point model was developed to predict AsTOT concentrations based on Eh and pH, to determine changes in the AsTOT-Eh relationship. The model captured the Eh change-point (∼-100±15mV), which was compatible with the data. Importantly, the inclusion of this change-point in the model resulted in improved model fit and prediction accuracy; AsTOT concentrations were strongly negatively related to Eh values higher than the change-point. The process underlying this relationship was subsequently posited to be the reductive dissolution of mineral oxides and As release. Overall, AsTOT showed a weak positive relationship with Eh at a lower range, similar to those commonly observed in the Mekong River basin delta. It is expected that these results would serve as a guide for establishing public health strategies in the Mekong River Basin. Copyright © 2015 Elsevier Ltd. All rights reserved.

The use of Pb isotopes to differentiate between contemporary and ancient sources of pollution in Greece

NASA Astrophysics Data System (ADS)

Åberg, G.; Charalampides, G.; Fosse, G.; Hjelmseth, H.

Stable lead isotopes are used to illustrate the relation source-receptor and to differentiate between sources of pollution in Greece. Air filters collected in the Kozani-Ptolemais lignite mining area, West Macedonia, point to an impact from gasoline lead as well as lead from the combustion of lignite. This is supported by lead isotope data of wheat grown on reclaimed land. Lead isotope analyses of contemporary teeth from the Lavrio sulphide mining area, southeast of Greece, show the imprint of previous mining activities as well as traffic emissions. Moreover, the Lavrio teeth can be distinguished from one tooth from Athens; the Athens tooth show a stronger impact of gasoline lead. Lead data also imply that the Greek top soil is contaminated by air pollution from earlier sulphide mining and smelting since Hellenic and Roman times.

Groundwater vulnerability and risk mapping using GIS, modeling and a fuzzy logic tool.

PubMed

Nobre, R C M; Rotunno Filho, O C; Mansur, W J; Nobre, M M M; Cosenza, C A N

2007-12-07

A groundwater vulnerability and risk mapping assessment, based on a source-pathway-receptor approach, is presented for an urban coastal aquifer in northeastern Brazil. A modified version of the DRASTIC methodology was used to map the intrinsic and specific groundwater vulnerability of a 292 km(2) study area. A fuzzy hierarchy methodology was adopted to evaluate the potential contaminant source index, including diffuse and point sources. Numerical modeling was performed for delineation of well capture zones, using MODFLOW and MODPATH. The integration of these elements provided the mechanism to assess groundwater pollution risks and identify areas that must be prioritized in terms of groundwater monitoring and restriction on use. A groundwater quality index based on nitrate and chloride concentrations was calculated, which had a positive correlation with the specific vulnerability index.

Fate and Transport Modeling of Selected Chlorinated Organic Compounds at Operable Unit 1, U.S. Naval Air Station, Jacksonville, Florida

USGS Publications Warehouse

Davis, J. Hal

2007-01-01

The U.S. Naval Air Station occupies 3,800 acres adjacent to the St. Johns River in Jacksonville, Florida. The Station was placed on the U.S. Environmental Protection Agency's National Priorities List in December 1989 and is participating in the U.S. Department of Defense Installation Restoration Program, which serves to identify and remediate environmental contamination. One contaminated site, the old landfill, was designated as Operable Unit 1 (OU1) in 1989. The major source of ground-water contamination was from the disposal of waste oil and solvents into open pits, which began in the 1940s. Several remedial measures were implemented at this site to prevent the spread of contamination. Recovery trenches were installed in 1995 to collect free product. In 1998, some of the contamination was consolidated to the center of the old landfill and covered by an impermeable cap. Currently, Operable Unit 1 is being reevaluated as part of a 5-year review process to determine if the remedial actions were effective. Solute transport modeling indicated that the concentration of contaminants would have reached its maximum extent by the 1970s, after which the concentration levels would have generally declined because the pits would have ceased releasing high levels of contaminants. In the southern part of the site, monitoring well MW-19, which had some of the highest levels of contamination, showed decreases for measured and simulated concentrations of trichloroethene (TCE) and dichloroethene (DCE) from 1992 to present. Two upgradient disposal pits were simulated to have ceased releasing high levels of contamination in 1979, which consequently caused a drop in simulated concentrations. Monitoring well MW-100 had the highest levels of contamination of any well directly adjacent to a creek. Solute transport modeling substantially overestimated the concentrations of TCE, DCE, and vinyl chloride (VC) in this well. The reason for this overestimation is not clear, however, it indicates that the model will be conservative when used to predict concentration levels and the time required for the contamination to move through the system. Monitoring well MW-97 had the highest levels of contamination in the central part of the site. The levels decreased for both the measured and simulated values of TCE, DCE, and VC from 1999 to present. Simulating the source area as ceasing to release high levels of contamination in 1979 caused the drop in concentration, which began in the 1990s at this well. Monitoring well MW-89 had the highest levels of contamination in the northern part of the site. In order to match the low levels of contamination in wells MW-12 and MW-93, the pit was simulated as ceasing to release contamination in 1970; however, the installation of a trench in 1995 could have caused the source area to release additional contamination from 1995 to 1998. The effect of the additional dissolution was a spike in contamination at MW-89, beginning in about 1996 and continuing until the present time. Results from the last several sampling events indicate that the TCE and DCE levels could be decreasing, but VC shows no apparent trend. Several more years of sampling are needed to determine if these trends are continuing. Based on the solute transport modeling predictions, TCE, DCE, and VC will have migrated to the vicinity of creeks that drain ground water from the aquifer by 2010, and only relatively low levels will remain in the aquifer by 2015. Because the creeks represent the point where the contaminated ground water comes into contact with the environment, future contamination levels are a concern. The concentration of chlorinated solvents in the creek water has always been relatively low. Because the model shows that concentrations of TCE, DCE, and VC are declining in the aquifer, contamination levels in the creeks also are anticipated to decline.

Screening tool to evaluate the vulnerability of down-gradient receptors to groundwater contaminants from uncapped landfills

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baker, Ronald J.; Reilly, Timothy J.; Lopez, Anthony

2015-09-15

Highlights: • A spreadsheet-based risk screening tool for groundwater affected by landfills is presented. • Domenico solute transport equations are used to estimate downgradient contaminant concentrations. • Landfills are categorized as presenting high, moderate or low risks. • Analysis of parameter sensitivity and examples of the method’s application are given. • The method has value to regulators and those considering redeveloping closed landfills. - Abstract: A screening tool for quantifying levels of concern for contaminants detected in monitoring wells on or near landfills to down-gradient receptors (streams, wetlands and residential lots) was developed and evaluated. The tool uses Quick Domenicomore » Multi-scenario (QDM), a spreadsheet implementation of Domenico-based solute transport, to estimate concentrations of contaminants reaching receptors under steady-state conditions from a constant-strength source. Unlike most other available Domenico-based model applications, QDM calculates the time for down-gradient contaminant concentrations to approach steady state and appropriate dispersivity values, and allows for up to fifty simulations on a single spreadsheet. Sensitivity of QDM solutions to critical model parameters was quantified. The screening tool uses QDM results to categorize landfills as having high, moderate and low levels of concern, based on contaminant concentrations reaching receptors relative to regulatory concentrations. The application of this tool was demonstrated by assessing levels of concern (as defined by the New Jersey Pinelands Commission) for thirty closed, uncapped landfills in the New Jersey Pinelands National Reserve, using historic water-quality data from monitoring wells on and near landfills and hydraulic parameters from regional flow models. Twelve of these landfills are categorized as having high levels of concern, indicating a need for further assessment. This tool is not a replacement for conventional numerically-based transport model or other available Domenico-based applications, but is suitable for quickly assessing the level of concern posed by a landfill or other contaminant point source before expensive and lengthy monitoring or remediation measures are taken. In addition to quantifying the level of concern using historic groundwater-monitoring data, the tool allows for archiving model scenarios and adding refinements as new data become available.« less

A multiple-point geostatistical method for characterizing uncertainty of subsurface alluvial units and its effects on flow and transport

USGS Publications Warehouse

Cronkite-Ratcliff, C.; Phelps, G.A.; Boucher, A.

2012-01-01

This report provides a proof-of-concept to demonstrate the potential application of multiple-point geostatistics for characterizing geologic heterogeneity and its effect on flow and transport simulation. The study presented in this report is the result of collaboration between the U.S. Geological Survey (USGS) and Stanford University. This collaboration focused on improving the characterization of alluvial deposits by incorporating prior knowledge of geologic structure and estimating the uncertainty of the modeled geologic units. In this study, geologic heterogeneity of alluvial units is characterized as a set of stochastic realizations, and uncertainty is indicated by variability in the results of flow and transport simulations for this set of realizations. This approach is tested on a hypothetical geologic scenario developed using data from the alluvial deposits in Yucca Flat, Nevada. Yucca Flat was chosen as a data source for this test case because it includes both complex geologic and hydrologic characteristics and also contains a substantial amount of both surface and subsurface geologic data. Multiple-point geostatistics is used to model geologic heterogeneity in the subsurface. A three-dimensional (3D) model of spatial variability is developed by integrating alluvial units mapped at the surface with vertical drill-hole data. The SNESIM (Single Normal Equation Simulation) algorithm is used to represent geologic heterogeneity stochastically by generating 20 realizations, each of which represents an equally probable geologic scenario. A 3D numerical model is used to simulate groundwater flow and contaminant transport for each realization, producing a distribution of flow and transport responses to the geologic heterogeneity. From this distribution of flow and transport responses, the frequency of exceeding a given contaminant concentration threshold can be used as an indicator of uncertainty about the location of the contaminant plume boundary.

Organic contaminants in onsite wastewater treatment systems

USGS Publications Warehouse

Conn, K.E.; Siegrist, R.L.; Barber, L.B.; Brown, G.K.

2007-01-01

Wastewater from thirty onsite wastewater treatment systems was sampled during a reconnaissance field study to quantify bulk parameters and the occurrence of organic wastewater contaminants including endocrine disrupting compounds in treatment systems representing a variety of wastewater sources and treatment processes and their receiving environments. Bulk parameters ranged in concentrations representative of the wide variety of wastewater sources (residential vs. non-residential). Organic contaminants such as sterols, surfactant metabolites, antimicrobial agents, stimulants, metal-chelating agents, and other consumer product chemicals, measured by gas chromatography/mass spectrometry were detected frequently in onsite system wastewater. Wastewater composition was unique between source type likely due to differences in source water and chemical usage. Removal efficiencies varied by engineered treatment type and physicochemical properties of the contaminant, resulting in discharge to the soil treatment unit at ecotoxicologically-relevant concentrations. Organic wastewater contaminants were detected less frequently and at lower concentrations in onsite system receiving environments. Understanding the occurrence and fate of organic wastewater contaminants in onsite wastewater treatment systems will aid in minimizing risk to ecological and human health.

A Space Experiment to Measure the Atomic Oxygen Erosion of Polymers and Demonstrate a Technique to Identify Sources of Silicone Contamination

NASA Technical Reports Server (NTRS)

Banks, Bruce A.; deGroh, Kim K.; Baney-Barton, Elyse; Sechkar, Edward A.; Hunt, Patricia K.; Willoughby, Alan; Bemer, Meagan; Hope, Stephanie; Koo, Julie; Kaminski, Carolyn;

Sources and contamination routes of microbial pathogens to fresh produce during field cultivation: A review.

PubMed

Alegbeleye, Oluwadara Oluwaseun; Singleton, Ian; Sant'Ana, Anderson S

2018-08-01

Foodborne illness resulting from the consumption of contaminated fresh produce is a common phenomenon and has severe effects on human health together with severe economic and social impacts. The implications of foodborne diseases associated with fresh produce have urged research into the numerous ways and mechanisms through which pathogens may gain access to produce, thereby compromising microbiological safety. This review provides a background on the various sources and pathways through which pathogenic bacteria contaminate fresh produce; the survival and proliferation of pathogens on fresh produce while growing and potential methods to reduce microbial contamination before harvest. Some of the established bacterial contamination sources include contaminated manure, irrigation water, soil, livestock/ wildlife, and numerous factors influence the incidence, fate, transport, survival and proliferation of pathogens in the wide variety of sources where they are found. Once pathogenic bacteria have been introduced into the growing environment, they can colonize and persist on fresh produce using a variety of mechanisms. Overall, microbiological hazards are significant; therefore, ways to reduce sources of contamination and a deeper understanding of pathogen survival and growth on fresh produce in the field are required to reduce risk to human health and the associated economic consequences. Copyright © 2018 Elsevier Ltd. All rights reserved.

Geochemistry and petrogenesis of lava flows around Linga, Chhindwara area in the Eastern Deccan Volcanic Province (EDVP), India

NASA Astrophysics Data System (ADS)

Ganguly, Sohini; Ray, Jyotisankar; Koeberl, Christian; Saha, Abhishek; Thöni, Martin; Balaram, V.

2014-09-01

Based on systematic three-tier arrangement of vesicles, entablature and columnar joints, three distinct quartz normative tholeiitic lava flows (I, II and III) were recognized in the area around Linga, in the Eastern Deccan Volcanic Province (EDVP). Each of the flows exhibits intraflow chemical variations marked by high Mg#-low Ti, and low Mg#-high Ti contents. The MgO (4.27-7.74 wt.%), Mg# (23.45-41.89) and Zr (161.5-246.3 ppm) of Linga flows suggest an evolved chemistry marked by fractional crystallization and crustal contamination processes. Positive Rb and Th anomalies, negative Nb anomalies, relative enrichment of LILE-LREE with respect to Nb, Nb/Th:3.71-6.77 indicate crustal contamination of magma by continental materials through magma-crust interaction during melt migration and contributions from sub-continental lithospheric mantle (SCLM). Negative K, Sr and Ti anomalies corroborate an intracontinental, rift-controlled tectonic setting for the genesis and evolution of Linga basalts. Chondrite-normalized REE patterns reflect low HREE abundances and prominent LREE/HREE, MREE/HREE fractionation thereby pointing towards partial melting of garnet peridotite mantle source. Nb, Zr, Y variations suggest 10-15% partial melting of mantle source for the derivation of parent tholeiitic melt that suffered crystal fractionation of phenocrystal phases and subsequent liquid immiscibility. Critical evaluation of Srinitial and Ndinitial (65 Ma) isotopic compositions (87Sr/86Srinitial between 0.705656 and 0.706980 and 143Nd/144Ndinitial between 0.512523 and 0.512598) suggests that these basalts were derived from an enriched mantle (∼EM I-EM II) source. The εSr (21.84-41.27) and εNd (-0.28 to 1.10) isotopic signatures defined by higher εSr and lower εNd fingerprint a plume-related source. Positive and negative values of εNd indicate an isotopically heterogeneous mantle source marked by mixing of depleted (DM) and enriched mantle (EM I-EM II) components at the source region and together with 87Sr/86Srinitial ranging from 0.705656 to 0.706980 suggest two stage contamination of parent magma which is much similar to that of Poladpur, Toranmal, Mhow, Chikaldara flows. Ba/Y versus 87Sr/86Sr and Nb/Y versus Rb/Y variations show an Ambenali-Poladpur contamination trend for the Linga basalts thereby suggesting the role of upper continental granitic crust as the contaminant of these flows through magma-crust interaction during melt migration. The lava flows of Linga are geochemically correlatable with the Poladpur flows of southwestern and Toranmal flows of northern Deccan and show genetic coherence with the basalts of Jabalpur, Seoni, Chakhla-Delakhari of eastern Deccan.

Application of the Approximate Bayesian Computation methods in the stochastic estimation of atmospheric contamination parameters for mobile sources

NASA Astrophysics Data System (ADS)

Kopka, Piotr; Wawrzynczak, Anna; Borysiewicz, Mieczyslaw

2016-11-01

In this paper the Bayesian methodology, known as Approximate Bayesian Computation (ABC), is applied to the problem of the atmospheric contamination source identification. The algorithm input data are on-line arriving concentrations of the released substance registered by the distributed sensors network. This paper presents the Sequential ABC algorithm in detail and tests its efficiency in estimation of probabilistic distributions of atmospheric release parameters of a mobile contamination source. The developed algorithms are tested using the data from Over-Land Atmospheric Diffusion (OLAD) field tracer experiment. The paper demonstrates estimation of seven parameters characterizing the contamination source, i.e.: contamination source starting position (x,y), the direction of the motion of the source (d), its velocity (v), release rate (q), start time of release (ts) and its duration (td). The online-arriving new concentrations dynamically update the probability distributions of search parameters. The atmospheric dispersion Second-order Closure Integrated PUFF (SCIPUFF) Model is used as the forward model to predict the concentrations at the sensors locations.

Seabird colonies as relevant sources of pollutants in Antarctic ecosystems: Part 1 - Trace elements.

PubMed

Cipro, C V Z; Bustamante, P; Petry, M V; Montone, R C

2018-08-01

Global distillation is classically pointed as the biggest responsible for contaminant inputs in Polar ecosystems. Mercury (Hg) and other trace elements (TEs) also present natural sources, whereas the biologically mediated input is typically ignored. However, bioaccumulation and biomagnification combined with the fact that seabirds gather in large numbers into large colonies and excrete on land might represent an important local TEs input. A previous work suggested these colonies as sources of not only nutrients, but also organic contaminants. To evaluate a similar hypothesis for TEs, samples of lichen (n = 55), mosses (n = 58) and soil (n = 37) were collected in 13 locations within the South Shetlands Archipelago during the austral summers of 2013-14 and 2014-15. They were divided in: "colony" (within the colony itself for soil and bordering it for vegetation) and "control" (at least 50 m away from colony interference), analysed for TEs (As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, V, and Zn) and stable isotopes (C and N). In most cases, soil seems the best matrix to assess colonies as TEs sources, as it presented more differences between control/colony sites than vegetation. Colonies are clearly local sources of organic matter, Cd, Hg and likely of As, Se and Zn. Conversely, Co, Cr, Ni and Pb come presumably from other sources, natural or anthropogenic. In general, isotopes were more useful for interpreting vegetation data due to fractionation of absorbed animal-derived organic matter. Other local Hg sources could be inferred from high levels in control sites, location and wind patterns. Copyright © 2018 Elsevier Ltd. All rights reserved.

Characterization of sources and loadings of fecal pollutants using microbial source tracking assays in urban and rural areas of the Grand River Watershed, Southwestern Ontario.

PubMed

Lee, Dae-Young; Lee, Hung; Trevors, Jack T; Weir, Susan C; Thomas, Janis L; Habash, Marc

2014-04-15

Sources of fecal water pollution were assessed in the Grand River and two of its tributaries (Ontario, Canada) using total and host-specific (human and bovine) Bacteroidales genetic markers in conjunction with reference information, such as land use and weather. In-stream levels of the markers and culturable Escherichia coli were also monitored during multiple rain events to gain information on fecal loadings to catchment from diffuse sources. Elevated human-specific marker levels were accurately identified in river water impacted by a municipal wastewater treatment plant (WWTP) effluent and at a downstream site in the Grand River. In contrast, the bovine-specific marker showed high levels of cattle fecal pollution in two tributaries, both of which are characterized as intensely farmed areas. The bovine-specific Bacteroidales marker increased with rainfall in the agricultural tributaries, indicating enhanced loading of cattle-derived fecal pollutants to river from non-point sources following rain events. However, rain-triggered fecal loading was not substantiated in urban settings, indicating continuous inputs of human-originated fecal pollutants from point sources, such as WWTP effluent. This study demonstrated that the Bacteroidales source tracking assays, in combination with land use information and hydrological data, may provide additional insight into the spatial and temporal distribution of source-specific fecal contamination in streams impacted by varying land uses. Using the approach described in this study may help to characterize impacted water sources and to design targeted land use management plans in other watersheds in the future. Copyright © 2014 Elsevier Ltd. All rights reserved.

Characterization and identification of Na-Cl sources in ground water

USGS Publications Warehouse

Panno, S.V.; Hackley, Keith C.; Hwang, H.-H.; Greenberg, S.E.; Krapac, I.G.; Landsberger, S.; O'Kelly, D. J.

2006-01-01

Elevated concentrations of sodium (Na+) and chloride (Cl -) in surface and ground water are common in the United States and other countries, and can serve as indicators of, or may constitute, a water quality problem. We have characterized the most prevalent natural and anthropogenic sources of Na+ and Cl- in ground water, primarily in Illinois, and explored techniques that could be used to identify their source. We considered seven potential sources that included agricultural chemicals, septic effluent, animal waste, municipal landfill leachate, sea water, basin brines, and road deicers. The halides Cl-, bromide (Br-), and iodide (I-) were useful indicators of the sources of Na+-Cl- contamination. Iodide enrichment (relative to Cl-) was greatest in precipitation, followed by uncontaminated soil water and ground water, and landfill leachate. The mass ratios of the halides among themselves, with total nitrogen (N), and with Na+ provided diagnostic methods for graphically distinguishing among sources of Na+ and Cl- in contaminated water. Cl/Br ratios relative to Cl- revealed a clear, although overlapping, separation of sample groups. Samples of landfill leachate and ground water known to be contaminated by leachate were enriched in I- and Br-; this provided an excellent fingerprint for identifying leachate contamination. In addition, total N, when plotted against Cl/Br ratios, successfully separated water contaminated by road salt from water contaminated by other sources. Copyright ?? 2005 National Ground Water Association.

Utility of Microbial Source-Tracking Markers for Assessing Fecal Contamination in the Portage River Watershed, Northwestern Ohio, 2008

USGS Publications Warehouse

Kephart, Christopher M.; Bushon, Rebecca N.

2010-01-01

An influx of concentrated animal feeding operations in northwest Ohio has prompted local agencies to examine the effects of these industrial farms on water quality in the upper Portage River watershed. The utility of microbial source-tracking (MST) tools as a means of characterizing sources of fecal contamination in the watershed was evaluated. From 2007 to 2008, scientists with the U.S. Geological Survey, Bowling Green State University, and the Wood County Health Department collected and analyzed 17 environmental samples and 13 fecal source samples for Bacteroides-based host-associated DNA markers. At many of the environmental sites tested, MST marker results corroborated the presumptive fecal contamination sources. Results from this demonstration study support the utility of using MST with host-specific molecular markers to characterize the sources of fecal contamination in the Portage River watershed.

[Groundwater organic pollution source identification technology system research and application].

PubMed

Wang, Xiao-Hong; Wei, Jia-Hua; Cheng, Zhi-Neng; Liu, Pei-Bin; Ji, Yi-Qun; Zhang, Gan

2013-02-01

Groundwater organic pollutions are found in large amount of locations, and the pollutions are widely spread once onset; which is hard to identify and control. The key process to control and govern groundwater pollution is how to control the sources of pollution and reduce the danger to groundwater. This paper introduced typical contaminated sites as an example; then carried out the source identification studies and established groundwater organic pollution source identification system, finally applied the system to the identification of typical contaminated sites. First, grasp the basis of the contaminated sites of geological and hydrogeological conditions; determine the contaminated sites characteristics of pollutants as carbon tetrachloride, from the large numbers of groundwater analysis and test data; then find the solute transport model of contaminated sites and compound-specific isotope techniques. At last, through groundwater solute transport model and compound-specific isotope technology, determine the distribution of the typical site of organic sources of pollution and pollution status; invest identified potential sources of pollution and sample the soil to analysis. It turns out that the results of two identified historical pollution sources and pollutant concentration distribution are reliable. The results provided the basis for treatment of groundwater pollution.

Microbiological quality of pastrami and associated surfaces at the point of sale in Kayseri, Turkey.

PubMed

Yildirim, Y; Ertas Onmaz, N; Gonulalan, Z; Al, S; Yildirim, A; Karadal, F; Hizlisoy, H; Pamuk, Ş

2017-05-01

The aim of this study is to trace the possible relations between the hygienic status of slicing utensils and the microbiological quality of pastrami. A total of 75 pastrami retail markets were visited in Kayseri, Turkey, where the pastrami (a ready-to-eat meat product) is commonly produced and consumed. Sliced pastrami, the cutting board and knife surface swabs were collected from each pastrami retail point to trace possible sources of contamination. Samples were analysed for the presence of total viable counts (TVC), total coliforms, Escherichia coli, members of Enterobacteriaceae, Staphylococcus aureus and Listeria spp. In addition, pastrami samples were analysed for sulphite-reducing Clostridium spp. and Toxoplasma gondii. When compared with the target values of related literatures, a total of 6 (8%) pastrami samples were found unsatisfactory as a result of TVC (5.3%), Enterobacteriaceae (5.3%), E. coli (2.6%), S. aureus (2.6%), Listeria spp. (2.6%) and Listeria monocytogenes (1.3%) contaminations. No T. gondii positivity was observed among the pastrami samples. None of the cutting board and knife surface swabs were found to harbour TVC level >10 3  cfu/cm 2 , E. coli and L. monocytogenes. For the total coliforms, 7 (9.3%) and 5 (6.6%) of cutting board and knife surface swabs were found to exceed the target value (<2.5 cfu/cm 2 ), respectively. No statistically significant correlation was detected between the organisms on pastrami and slicing utensils indicating that pastrami were not cross-contaminated by the contact surfaces. More emphasis needs to be placed for training of food handlers and to apply good hygienic practices at the point of pastrami sale. The conditions at retail points must be monitored and inspections should be tightened to protect public health. Copyright © 2017 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

Characterization of Boron Contamination in Fluorine Implantation using Boron Trifluoride as a Source Material

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schmeide, Matthias; Kondratenko, Serguei

2011-01-07

Fluorine implantation process purity was considered on different types of high current implanters. It was found that implanters equipped with an indirectly heated cathode ion source show an enhanced deep boron contamination compared to a high current implanter using a cold RF-driven multicusp ion source when boron trifluoride is used for fluorine implantations. This contamination is directly related to the source technology and thus, should be considered potentially for any implanter design using hot cathode/hot filament ion source, independently of the manufacturer.The boron contamination results from the generation of double charged boron ions in the arc chamber and the subsequentmore » charge exchange reaction to single charged boron ions taking place between the arc chamber and the extraction electrode. The generation of the double charged boron ions depends mostly on the source parameters, whereas the pressure in the region between the arc chamber and the extraction electrode is mostly responsible for the charge exchange from double charged to single charged ions. The apparent mass covers a wide range, starting at mass 11. A portion of boron ions with energies of (19/11) times higher than fluorine energy has the same magnetic rigidity as fluorine beam and cannot be separated by the analyzer magnet. The earlier described charge exchange effects between the extraction electrode and the entrance to the analyzer magnet, however, generates boron beam with a higher magnetic rigidity compared to fluorine beam and cannot cause boron contamination after mass-separation.The energetic boron contamination was studied as a function of the ion source parameters, such as gas flow, arc voltage, and source magnet settings, as well as analyzing magnet aperture resolution. This allows process optimization reducing boron contamination to the level acceptable for device performance.« less

Origin of fecal contamination in waters from contrasted areas: stanols as Microbial Source Tracking markers.

PubMed

Derrien, M; Jardé, E; Gruau, G; Pourcher, A M; Gourmelon, M; Jadas-Hécart, A; Pierson Wickmann, A C

2012-09-01

Improving the microbiological quality of coastal and river waters relies on the development of reliable markers that are capable of determining sources of fecal pollution. Recently, a principal component analysis (PCA) method based on six stanol compounds (i.e. 5β-cholestan-3β-ol (coprostanol), 5β-cholestan-3α-ol (epicoprostanol), 24-methyl-5α-cholestan-3β-ol (campestanol), 24-ethyl-5α-cholestan-3β-ol (sitostanol), 24-ethyl-5β-cholestan-3β-ol (24-ethylcoprostanol) and 24-ethyl-5β-cholestan-3α-ol (24-ethylepicoprostanol)) was shown to be suitable for distinguishing between porcine and bovine feces. In this study, we tested if this PCA method, using the above six stanols, could be used as a tool in "Microbial Source Tracking (MST)" methods in water from areas of intensive agriculture where diffuse fecal contamination is often marked by the co-existence of human and animal sources. In particular, well-defined and stable clusters were found in PCA score plots clustering samples of "pure" human, bovine and porcine feces along with runoff and diluted waters in which the source of contamination is known. A good consistency was also observed between the source assignments made by the 6-stanol-based PCA method and the microbial markers for river waters contaminated by fecal matter of unknown origin. More generally, the tests conducted in this study argue for the addition of the PCA method based on six stanols in the MST toolbox to help identify fecal contamination sources. The data presented in this study show that this addition would improve the determination of fecal contamination sources when the contamination levels are low to moderate. Copyright © 2012 Elsevier Ltd. All rights reserved.

Simulation of ground-water flow in the St Peter aquifer in an area contaminated by coal-tar derivatives, St Louis Park, Minnesota

USGS Publications Warehouse

Lorenz, D.L.; Stark, J.R.

1990-01-01

Model simulations also indicated that drawdown caused by pumping two wells, each pumping at 75 gallons per minute and located about 1 mile southeast of the source of contamination, would be effective in controlling movement and volume of contaminated ground water in the immediate area of the source of contamination. Some contamination may already have moved beyond the influence of these wells, however, because of a complex set of hydraulic conditions.

Distribution and Source Identification of Pb Contamination in industrial soil

NASA Astrophysics Data System (ADS)

Ko, M. S.

2017-12-01

INTRODUCTION Lead (Pb) is toxic element that induce neurotoxic effect to human, because competition of Pb and Ca in nerve system. Lead is classified as a chalophile element and galena (PbS) is the major mineral. Although the Pb is not an abundant element in nature, various anthropogenic source has been enhanced Pb enrichment in the environment after the Industrial Revolution. The representative anthropogenic sources are batteries, paint, mining, smelting, and combustion of fossil fuel. Isotope analysis widely used to identify the Pb contamination source. The Pb has four stable isotopes that are 208Pb, 207Pb, 206Pb, and 204Pb in natural. The Pb is stable isotope and the ratios maintain during physical and chemical fractionation. Therefore, variations of Pb isotope abundance and relative ratios could imply the certain Pb contamination source. In this study, distributions and isotope ratios of Pb in industrial soil were used to identify the Pb contamination source and dispersion pathways. MATERIALS AND METHODS Soil samples were collected at depth 0­-6 m from an industrial area in Korea. The collected soil samples were dried and sieved under 2 mm. Soil pH, aqua-regia digestion and TCLP carried out using sieved soil sample. The isotope analysis was carried out to determine the abundance of Pb isotope. RESULTS AND DISCUSSION The study area was developed land for promotion of industrial facilities. The study area was forest in 1980, and the satellite image show the alterations of land use with time. The variations of land use imply the possibilities of bringing in external contaminated soil. The Pb concentrations in core samples revealed higher in lower soil compare with top soil. Especially, 4 m soil sample show highest Pb concentrations that are approximately 1500 mg/kg. This result indicated that certain Pb source existed at 4 m depth. CONCLUSIONS This study investigated the distribution and source identification of Pb in industrial soil. The land use and Pb concentration at depth indicated elusive contamination event or contamination sources. In order to identify the contamination source clearly, isotope and Pb compound/mineralogy analysis are necessary.

INTERIM RESULTS FROM A STUDY OF THE IMPACTS OF TIN(II) BASED MERCURY TREATMENT IN A SMALL STREAM ECOSYSTEM: TIMS BRANCH, SAVANNAH RIVER SITE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Looney, B.; Bryan, L.; Mathews, T.

2012-03-30

Mercury (Hg) has been identified as a 'persistent, bioaccumulative and toxic' pollutant with widespread impacts throughout North America and the world (EPA. 1997a, 1997b, 1998a, 1998b, 2000). Although most of the mercury in the environment is inorganic Hg, a small proportion of total Hg is transformed through the actions of aquatic microbes into methylmercury (MeHg). In contrast to virtually all other metals, MeHg biomagnifies or becomes increasingly concentrated as it is transferred through aquatic food chains so that the consumption of mercury contaminated fish is the primary route of this toxin to humans. For this reason, the ambient water qualitymore » criterion (AWQC) for mercury is based on a fish tissue endpoint rather than an aqueous Hg concentration, as the tissue concentration (e.g., < 0.3 {mu}g/g fillet) is considered to be a more consistent indicator of exposure and risk (EPA, 2001). Effective mercury remediation at point-source contaminated sites requires an understanding of the nature and magnitude of mercury inputs, and also knowledge of how these inputs must be controlled in order to achieve the desired reduction of mercury contamination in biota necessary for compliance with AWQC targets. One of the challenges to remediation is that mercury body burdens in fish are more closely linked to aqueous MeHg than to inorganic Hg concentrations (Sveinsdottir and Mason 2005), but MeHg production is not easily predicted or controlled. At point-source contaminated sites, mercury methylation is not only affected by the absolute mercury load, but also by the form of mercury loaded. In addition, once MeHg is formed, the hydrology, trophic structure, and water chemistry of a given system affect how it is transformed and transferred through the food chain to fish. Decreasing inorganic Hg concentrations and loading may often therefore be a more achievable remediation goal, but has led to mixed results in terms of responses in fish bioaccumulation. A number of source control measures have resulted in rapid responses in lake or reservoir fisheries (Joslin 1994, Turner and Southworth 1999; Orihel et al., 2007), but examples of similar responses in Hg-contaminated stream ecosystems are less common. Recent work suggests that stream systems may actually be more susceptible to mercury bioaccumulation than lakes, highlighting the need to better understand the ecological drivers of mercury bioaccumulation in stream-dwelling fish (Chasar et al. 2009, Ward et al. 2010). In the present study we examine the response of fish to remedial actions in Tims Branch, a point-source contaminated stream on the Department of Energy's (DOE) Savannah River Site in Aiken, South Carolina. This second order stream received inorganic mercury inputs at its headwaters from the 1950s-2000s which contaminated the water, sediments, and biota downstream. In 2007, an innovative mercury removal system using tin (II) chloride (stannous chloride, SnCl{sub 2}) was implemented at a pre-existing air stripper. Tin(II) reduces dissolved Hg (II) to Hg (0), which is removed by the air stripper. During this process, tin(II) is oxidized to tin (IV) which is expected to precipitate as colloidal tin(IV) oxides and hydroxides, particulate materials with relatively low toxicity (Hallas and Cooney, 1981, EPA 2002, ATSDR, 2005). The objectives of the present research are to provide an initial assessment of the net impacts of the tin(II) based mercury treatment on key biota and to document the distribution and fate of inorganic tin in this small stream ecosystem after the first several years of operating a full scale system. To support these objectives, we collected fish, sediment, water, invertebrates, and biofilm samples from Tims Branch to quantify the general behavior and accumulation patterns for mercury and tin in the ecosystem and to determine if the treatment process has resulted in: (1) a measurable beneficial impact on (i.e., decrease of) mercury concentration in upper trophic level fish and other biota; this is a key environmental endpoint since reducing mercury concentration in fish is a primary regulatory driver for controlling mercury in streams; and (2) the potential for negative impacts associated with inorganic tin, including, biological transformation and uptake, and/or undesirable accumulation/focusing of tin to in key ecosystem compartments.« less

Sources and contamination rate of port sediments: evidences from dimensional, mineralogical, and chemical investigations

NASA Astrophysics Data System (ADS)

Lucchetti, Gabriella; Cutroneo, Laura; Carbone, Cristina; Consani, Sirio; Vagge, Greta; Canepa, Giuseppe; Capello, Marco

2017-04-01

Ports are complex environments due to their complicated geometry (quays, channels, and piers), the presence of human activities (vessel traffic, yards, industries, and discharges), and natural factors (stream and torrent inputs, sea action, and currents). Due to the many activities that take place in a port, sediments and waters are often contaminated by different kinds of chemicals, such as hydrocarbons, dioxins, pesticides, nutrients, and metals. The contamination rate of a port basin is site specific and depends on the sources of contamination in the nearby urban system as well as the port system itself, such as city discharges and sewers, river intake, vessel traffic, factories (Taylor and Owens, 2009). Moreover, two important sources and vehicles of contaminants are: a) anthropogenic road deposited sediments derived from the runoff of the port and city area, and natural road deposited sediments derived from rivers and torrents, and b) airborne particulate matter and sediments (Taylor and Owens, 2009). The Port of Genoa is situated at the apex of the Ligurian Sea in the north western Mediterranean Sea and is characterised by the presence of several commercial activities that have contributed, over the years, and still contribute today, to the contaminant accumulation in both the water column and the bottom sediments. This port basin includes the mouth of several streams and the mouth of the Bisagno and the Polcevera Torrents, along the banks of which can be found several small towns, quarries, factories, and the suburbs of the city of Genoa, a ferry terminal, different container terminals, marinas, dry docks, the coal power plant of Genoa, and different wastewater treatment plant discharges. Starting from these considerations, we have examined the marine environment of a port from the point of view of the water mass circulation, hydrological characteristics, distribution of the sediment grain size, mineralogical characteristics, and metal concentrations of the bottom sediments. Our results show that, in the case of the Port of Genoa (north western Italy), both the impact of the human activities (such as coal power plant, oil depots, yards, dredging of the bottom sediments, etc.) and the natural processes (such as currents, fresh water and sediment inputs from the torrents), together with the morphology of the basin, are important factors in sediment, water and metal distributions and give rise to a complex environment. Taylor, K.G., Owens, P.N., 2009. Sediments in urban river basins: a review of sediment contaminant dynamics in an environmental system conditioned by human activities. Journal of Soils and Sediments 9: 281-303.

Do forests represent a long-term source of contaminated particulate matter in the Fukushima Prefecture?

PubMed

Laceby, J Patrick; Huon, Sylvain; Onda, Yuichi; Vaury, Veronique; Evrard, Olivier

2016-12-01

The Fukushima Daiichi Nuclear Power Plant (FDNPP) accident resulted in radiocesium fallout contaminating coastal catchments of the Fukushima Prefecture. As the decontamination effort progresses, the potential downstream migration of radiocesium contaminated particulate matter from forests, which cover over 65% of the most contaminated region, requires investigation. Carbon and nitrogen elemental concentrations and stable isotope ratios are thus used to model the relative contributions of forest, cultivated and subsoil sources to deposited particulate matter in three contaminated coastal catchments. Samples were taken from the main identified sources: cultivated (n = 28), forest (n = 46), and subsoils (n = 25). Deposited particulate matter (n = 82) was sampled during four fieldwork campaigns from November 2012 to November 2014. A distribution modelling approach quantified relative source contributions with multiple combinations of element parameters (carbon only, nitrogen only, and four parameters) for two particle size fractions (<63 μm and <2 mm). Although there was significant particle size enrichment for the particulate matter parameters, these differences only resulted in a 6% (SD 3%) mean difference in relative source contributions. Further, the three different modelling approaches only resulted in a 4% (SD 3%) difference between relative source contributions. For each particulate matter sample, six models (i.e. <63 μm and <2 mm from the three modelling approaches) were used to incorporate a broader definition of potential uncertainty into model results. Forest sources were modelled to contribute 17% (SD 10%) of particulate matter indicating they present a long term potential source of radiocesium contaminated material in fallout impacted catchments. Subsoils contributed 45% (SD 26%) of particulate matter and cultivated sources contributed 38% (SD 19%). The reservoir of radiocesium in forested landscapes in the Fukushima region represents a potential long-term source of particulate contaminated matter that will require diligent management for the foreseeable future. Copyright © 2016 Elsevier Ltd. All rights reserved.

Migration of strontium-90 in surface water, groundwater and sediments of the Borschi watershed, Chernobyl

NASA Astrophysics Data System (ADS)

Freed, Rina

Effective stream remediation of non-point source contaminants, such as Chernobyl fallout, requires an understanding of the areas within watersheds that are contributing contamination to streams, the pathways of contaminant migration to streams, and the mechanisms controlling concentration changes in streams. From 1998--2002, the migration of 90Sr was studied in the Borschi watershed, a small (8.5 km2) catchment, three km south of the Chernobyl Nuclear Power Plant. Estimates of 90Sr depletion from soil cores (based on the ratio of 90Sr to the relatively immobile 154Eu) were used to map the effective source area that has contributed 90Sr loading into the main channel. The effective source areas include the channel bottom sediments, a wetland in the central region of the watershed, and periodically flooded soils surrounding the wetland. The estimated 90Sr leaching rate considering the effective source areas agrees with the estimate based on monitoring observations of stream water quality and flow rate in 1999--2001, 2.0% per year. In approximately 44 years, 90% of the remaining 90Sr could be removed from the effective source areas. We hypothesize that during discharge periods, the pore waters in the wetland represent the 90Sr concentration of advecting groundwater while during stagnant periods, the pore waters represent the concentration of 90Sr in equilibrium with the sediment. This proposed explanation is supported using PHREEQC in a dual porosity mode. Using independent estimates of the model parameters, the pore water concentration profiles could be successfully matched with the assumption of advective transport during the discharge period and diffusive transport of 90Sr during near-stagnant conditions. Changes in the 90Sr concentration of the Borschi stream are correlated with the elevation of the water table in the vicinity of the wetlands. The elevation of the water table is a surrogate variable for the area of submerged soil. As the area of submerged soil increases, more of the contaminant in the upper soil horizon is saturated and more 90Sr is released into the stream. In contrast to the prevailing assumption that the mechanism of 90Sr migration to streams is overland flow during storm events, over 70% of the annual flux occurs during baseflow conditions.

Aquitard contaminant storage and flux resulting from dense nonaqueous phase liquid source zone dissolution and remediation

EPA Science Inventory

A one-dimensional diffusion model was used to investigate the effects of dense non-aqueous phase liquid (DNAPL) source zone dissolution and remediation on the storage and release of contaminants from aquitards. Source zone dissolution was represented by a power-law source depleti...

Airborne bacterial contaminations in typical Chinese wet market with live poultry trade.

PubMed

Gao, Xin-Lei; Shao, Ming-Fei; Luo, Yi; Dong, Yu-Fang; Ouyang, Feng; Dong, Wen-Yi; Li, Ji

2016-12-01

Chinese wet markets with live poultry trade have been considered as major sources of pathogen dissemination, and sites for horizontal transfer of bacterial and viral pathogens. In this study, the pathogenic bacteria and antibiotic resistant genes (ARGs) in air samples collected at a typical Chinese wet market had been analysis and quantified. Corynebacterium minutissimum and other pathogenic bacteria accounted for 0.81-8.02% of the whole microbial community in different air samples. The four ARGs quantified in this study showed a comparable relative concentration (copies/ng_DNA) with municipal wastewater. Poultry manures were demonstrated to be important microbial contamination source in wet market, which was supported by both microbial composition based source tracking and the quantification of airborne microbial density. A series of Firmicutes and Bacteroidetes indicators of poultry area contamination were successfully screened, which will be useful for the more convenient monitoring of airborne poultry area contamination. Our results indicate bioaerosols acted as important route for the transmissions of pathogens and ARGs. Continued surveillance of airborne microbial contamination is required in poultry trade wet market. Urban live poultry markets are important sources of pathogen dissemination, and sites for horizontal transfer of viral and bacterial pathogens. In the present field-study, pathogenic bacteria and antibiotic resistance genes were focused to provide quantitative information on the levels of microbial contaminations at the indoor air of wet markets. Results demonstrated that poultry manures were important microbial contamination source in wet market, and in the meanwhile bioaerosols were identified as important route for the transmissions of microbial contaminants. A series of Firmicutes and Bacteroidetes indicators of poultry area contamination were successfully screened, which will be useful for the more convenient monitoring of airborne poultry area contamination. Copyright © 2016 Elsevier B.V. All rights reserved.

Guidance on managing dredged material contaminated with dioxins and furans

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chase, T.; Dillon, T.

Approximately 400 million cubic yards of sediment are dredged from US navigation channels every year. While the vast majority of the dredged material are clean and thereby suitable for aquatic disposal, a portion of the dredged material are contaminated with chemicals that may pose risks to human health and the ecological health of the aquatic environment. Contaminated dredged materials are most frequently found downstream of industrial and municipal sewage-treatment discharges; non-point sources of pollution (e.g., urban and agricultural runoff) also contribute to contamination of dredged materials. An increasing amount of dredged materials are being identified through more sophisticated testing regimesmore » to pose potentially adverse risks to human health and the aquatic environment. One particular class of chemicals that raises concern when regulating dredged material disposal is dioxin, which has been found in sediment in a number of locations, including New Jersey/New York Harbor. Further testing will likely find that dredged materials are contaminated with low levels of dioxin across the country. Decision makers in the EPA and the USACE are guided by numerous statutory mandates and regulations. Within that framework, judgments about the suitability of dredged material for aquatic disposal are made based upon a tiered testing and evaluative process. Recently, the EPA and the USACE have been working to incorporate risk-based evaluation procedures into the dredged material decision-making process. This paper discusses such efforts to date and the preliminary recommendations for evaluating the potential effects of dioxin contaminated dredged material.« less

Distributions of typical contaminant species in urban short-term storm runoff and their fates during rain events: a case of Xiamen City.

PubMed

Wei, Qunshan; Zhu, Gefu; Wu, Peng; Cui, Li; Zhang, Kaisong; Zhou, Jingjing; Zhang, Wenru

2010-01-01

The pollutants in urban storm runoff, which lead to an non-point source contamination of water environment around cities, are of great concerns. The distributions of typical contaminants and the variations of their species in short term storm runoff from different land surfaces in Xiamen City were investigated. The concentrations of various contaminants, including organic matter, nutrients (i.e., N and P) and heavy metals, were significantly higher in parking lot and road runoff than those in roof and lawn runoff. The early runoff samples from traffic road and parking lot contained much high total nitrogen (TN 6-19 mg/L) and total phosphorus (TP 1-3 mg/L). A large proportion (around 60%) of TN existed as total dissolved nitrogen (TDN) species in most runoff. The percentage of TDN and the percentage of total dissolved phosphorus remained relatively stable during the rain events and did not decrease as dramatically as TN and TP. In addition, only parking lot and road runoff were contaminated by heavy metals, and both Pb (25-120 microg/L) and Zn (0.1-1.2 mg/L) were major heavy metals contaminating both runoff. Soluble Pb and Zn were predominantly existed as labile complex species (50%-99%), which may be adsorbed onto the surfaces of suspended particles and could be easily released out when pH decreased. This would have the great impact to the environment.

Long-term survival of the Shiga toxin-producing Escherichia coli O104:H4 outbreak strain on fenugreek seeds.

PubMed

Knödler, Michael; Berger, Michael; Dobrindt, Ulrich

2016-10-01

A major outbreak of Shiga toxin-producing Escherichia coli (STEC) O104:H4 occurred in Germany in 2011. The epidemiological investigation revealed that a contaminated batch of fenugreek seeds (Trigonella foenum-graecum) was the most probable source of the pathogen. It was suggested that the most probable point of contamination was prior to leaving the importer, meaning that the seed contamination with STEC O104:H4 should have happened more than one year before the seeds were used for sprout production. Here, we investigated the capacity of STEC O104:H4 and closely related pathogenic as well as non-pathogenic Escherichia coli strains for long-term survival on dry fenugreek seeds. We did not observe a superior survival capacity of STEC O104:H4 on dry seeds. For none of the strains tested cultivatable cells were found without enrichment on contaminated seeds after more than 24 weeks of storage. Our findings suggest that contamination previous to the distribution from the importer may be less likely than previously assumed. We show that seeds contaminated with E. coli in extremely high numbers can be completely sterilized by a short treatment with bleach. This simple and cheap procedure does not affect the germination capacity of the seeds and could significantly improve safety in sprout production. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.