40 CFR 141.50 - Maximum contaminant level goals for organic contaminants.

Code of Federal Regulations, 2011 CFR

2011-07-01

... (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Maximum Contaminant Level... contaminants. (a) MCLGs are zero for the following contaminants: (1) Benzene (2) Vinyl chloride (3) Carbon...

Interactive effects of Cd and PAHs on contaminants removal from co-contaminated soil planted with hyperaccumulator plant Sedum alfredii

USDA-ARS?s Scientific Manuscript database

Soil contamination by multiple organic and inorganic contaminants is common but its remediation by hyperaccumulator plants is rarely reported. The growth of a cadmium (Cd) hyperaccumulator Sedum alfredii and removal of contaminants from Cd and polycyclic aromatic hydrocarbons(PAHs) co-contaminated s...

Directional phytoscreening: contaminant gradients in trees for plume delineation.

PubMed

Limmer, Matt A; Shetty, Mikhil K; Markus, Samantha; Kroeker, Ryan; Parker, Beth L; Martinez, Camilo; Burken, Joel G

2013-08-20

Tree sampling methods have been used in phytoscreening applications to delineate contaminated soil and groundwater, augmenting traditional investigative methods that are time-consuming, resource-intensive, invasive, and costly. In the past decade, contaminant concentrations in tree tissues have been shown to reflect the extent and intensity of subsurface contamination. This paper investigates a new phytoscreening tool: directional tree coring, a concept originating from field data that indicated azimuthal concentrations in tree trunks reflected the concentration gradients in the groundwater around the tree. To experimentally test this hypothesis, large diameter trees were subjected to subsurface contaminant concentration gradients in a greenhouse study. These trees were then analyzed for azimuthal concentration gradients in aboveground tree tissues, revealing contaminant centroids located on the side of the tree nearest the most contaminated groundwater. Tree coring at three field sites revealed sufficiently steep contaminant gradients in trees reflected nearby groundwater contaminant gradients. In practice, trees possessing steep contaminant gradients are indicators of steep subsurface contaminant gradients, providing compass-like information about the contaminant gradient, pointing investigators toward higher concentration regions of the plume.

Contamination Effects Due to Space Environmental Interactions

NASA Technical Reports Server (NTRS)

Chen, Philip T.; Paquin, Krista C. (Technical Monitor)

2001-01-01

Molecular and particulate contaminants are commonly generated from the orbital spacecraft operations that are under the influence of the space environment. Once generated, these contaminants may attach to the surfaces of the spacecraft or may remain in the vicinity of the spacecraft. In the event these contaminants come to rest on the surfaces of the spacecraft or situated in the line-of-sight of the observation path, they will create various degrees of contamination effect which may cause undesirable effects for normal spacecraft operations, There will be circumstances in which the spacecraft may be subjected to special space environment due to operational conditions. Interactions between contaminants and special space environment may alter or greatly increase the contamination effect due to the synergistic effect. This paper will address the various types of contamination generation on orbit, the general effects of the contamination on spacecraft systems, and the typical impacts on the spacecraft operations due to the contamination effect. In addition, this paper will explain the contamination effect induced by the space environment and will discuss the intensified contamination effect resulting from the synergistic effect with the special space environment.

Evaluation of Contamination Inspection and Analysis Methods through Modeling System Performance

NASA Technical Reports Server (NTRS)

Seasly, Elaine; Dever, Jason; Stuban, Steven M. F.

2016-01-01

Contamination is usually identified as a risk on the risk register for sensitive space systems hardware. Despite detailed, time-consuming, and costly contamination control efforts during assembly, integration, and test of space systems, contaminants are still found during visual inspections of hardware. Improved methods are needed to gather information during systems integration to catch potential contamination issues earlier and manage contamination risks better. This research explores evaluation of contamination inspection and analysis methods to determine optical system sensitivity to minimum detectable molecular contamination levels based on IEST-STD-CC1246E non-volatile residue (NVR) cleanliness levels. Potential future degradation of the system is modeled given chosen modules representative of optical elements in an optical system, minimum detectable molecular contamination levels for a chosen inspection and analysis method, and determining the effect of contamination on the system. By modeling system performance based on when molecular contamination is detected during systems integration and at what cleanliness level, the decision maker can perform trades amongst different inspection and analysis methods and determine if a planned method is adequate to meet system requirements and manage contamination risk.

Development of Hydro-Epidemiology Studies to Establish Relationships Between Source-Water Contamination and Preterm Birth

NASA Astrophysics Data System (ADS)

Padilla, I. Y.; Meeker, J.; Alshawabkeh, A.; Cordero, J.; Giese, R.; Loch-Caruso, R.

2010-12-01

Puerto Rico has the highest rate of preterm birth in United States. Preliminary investigations suggest that the increase in preterm birth rates in Puerto Rico cannot be explained by changes in known factors, and that there is sufficient evidence that exposure to some contaminants contributes to preterm birth. Contamination in Puerto Rico is extensive with more than 150 contaminated sites and a vast contamination of water resources. Of particular concern is the contamination in the north-coast karst aquifer. This aquifer provides important freshwater resources for human consumption. The same characteristics that make karst aquifers highly productive make them highly vulnerable to contamination and impart an enormous capacity to store and convey contaminants from sources to potential exposures zones. As a result, there is an inherent risk of exposure to contamination thorough groundwater. This presentation will address work being conducted to: assess the extent of groundwater contamination in the north coast of Puerto Rico; evaluate potential relationship between exposure to contaminants and preterm birth; develop new technology for discovery, transport characterization, and green remediation of contaminants in karst aquifers.

Appropriate sampling strategy and analytical methodology to address contamination by industry. Part 2: Geochemistry and speciation analysis

NASA Astrophysics Data System (ADS)

Shtiza, Aurela; Swennen, Rudy

2011-03-01

The degree of contamination in soils, sediments and dusts can be assessed based on knowledge of a variety of factors, such as industrialization, type of contaminants, deposition conditions, contamination-control techniques, along with the characteristics of the recipient environmental compartments, which include pathways for contamination transport, depth of infiltration, and degree of groundwater contamination. The impact of contaminants also depends on the quantity, mobility and speciation of contaminants/wastes as well as on the sensitivity of the recipient compartments. With sufficient knowledge of these factors, a number of conclusions can be drawn concerning the status of contamination in industrialized areas. This literature review aims to scrutinize some of the methods used to analyse the occurrence, speciation, mobility, bioavailability and likely the toxic effects of contaminants in the environment.

Linking field-based metabolomics and chemical analyses to prioritize contaminants of emerging concern in the Great Lakes basin

USGS Publications Warehouse

Davis, John M.; Ekman, Drew R.; Teng, Quincy; Ankley, Gerald T.; Berninger, Jason P.; Cavallin, Jenna E.; Jensen, Kathleen M.; Kahl, Michael D.; Schroeder, Anthony L.; Villeneuve, Daniel L.; Jorgenson, Zachary G.; Lee, Kathy E.; Collette, Timothy W.

2016-01-01

The ability to focus on the most biologically relevant contaminants affecting aquatic ecosystems can be challenging because toxicity-assessment programs have not kept pace with the growing number of contaminants requiring testing. Because it has proven effective at assessing the biological impacts of potentially toxic contaminants, profiling of endogenous metabolites (metabolomics) may help screen out contaminants with a lower likelihood of eliciting biological impacts, thereby prioritizing the most biologically important contaminants. The authors present results from a study that utilized cage-deployed fathead minnows (Pimephales promelas) at 18 sites across the Great Lakes basin. They measured water temperature and contaminant concentrations in water samples (132 contaminants targeted, 86 detected) and used 1H-nuclear magnetic resonance spectroscopy to measure endogenous metabolites in polar extracts of livers. They used partial least-squares regression to compare relative abundances of endogenous metabolites with contaminant concentrations and temperature. The results indicated that profiles of endogenous polar metabolites covaried with at most 49 contaminants. The authors identified up to 52% of detected contaminants as not significantly covarying with changes in endogenous metabolites, suggesting they likely were not eliciting measurable impacts at these sites. This represents a first step in screening for the biological relevance of detected contaminants by shortening lists of contaminants potentially affecting these sites. Such information may allow risk assessors to prioritize contaminants and focus toxicity testing on the most biologically relevant contaminants. Environ Toxicol Chem 2016;35:2493–2502.

Chronic contamination decreases disease spread: a Daphnia–fungus–copper case study

PubMed Central

Civitello, David J.; Forys, Philip; Johnson, Adam P.; Hall, Spencer R.

2012-01-01

Chemical contamination and disease outbreaks have increased in many ecosystems. However, connecting pollution to disease spread remains difficult, in part, because contaminants can simultaneously exert direct and multi-generational effects on several host and parasite traits. To address these challenges, we parametrized a model using a zooplankton–fungus–copper system. In individual-level assays, we considered three sublethal contamination scenarios: no contamination, single-generation contamination (hosts and parasites exposed only during the assays) and multi-generational contamination (hosts and parasites exposed for several generations prior to and during the assays). Contamination boosted transmission by increasing contact of hosts with parasites. However, it diminished parasite reproduction by reducing the size and lifespan of infected hosts. Multi-generational contamination further reduced parasite reproduction. The parametrized model predicted that a single generation of contamination would enhance disease spread (via enhanced transmission), whereas multi-generational contamination would inhibit epidemics relative to unpolluted conditions (through greatly depressed parasite reproduction). In a population-level experiment, multi-generational contamination reduced the size of experimental epidemics but did not affect Daphnia populations without disease. This result highlights the importance of multi-generational effects for disease dynamics. Such integration of models with experiments can provide predictive power for disease problems in contaminated environments. PMID:22593104

A Factor Increasing Venous Contamination on Bolus Chase Three-dimensional Magnetic Resonance Imaging: Charcot Neuroarthropathy.

PubMed

Çildağ, Mehmet B; Ertuğrul, Mustafa B; Köseoğlu, Ömer Fk; Armstrong, David G

2018-01-01

The study aimed to evaluate the ratio of venous contamination in diabetic cases without foot lesion, with foot lesion and with Charcot neuroarthropathy (CN). Bolus-chase three-dimensional magnetic resonance (MR) of 396 extremities of patients with diabetes mellitus was analyzed, retrospectively. Extremities were divided into three groups as follows: diabetic patients without foot ulcer or Charcot arthropathy (Group A), patients with diabetic foot ulcers (Group B) and patients with CN accompanying diabetic foot ulcers (Group C). Furthermore, amount of venous contamination classified as no venous contamination, mild venous contamination, and severe venous contamination. The relationship between venous contamination and extremity groups was investigated. Severe venous contamination was seen in Group A, Group B, and Group C, 5.6%, 15.2%, and 34.1%, respectively. Statistically significant difference was seen between groups with regard to venous contamination. Venous contamination following bolus chase MR was higher in patients with CN.

Space station contamination control study: Internal combustion, phase 1

NASA Technical Reports Server (NTRS)

Ruggeri, Robert T.

1987-01-01

Contamination inside Space Station modules was studied to determine the best methods of controlling contamination. The work was conducted in five tasks that identified existing contamination control requirements, analyzed contamination levels, developed outgassing specification for materials, wrote a contamination control plan, and evaluated current materials of offgassing tests used by NASA. It is concluded that current contamination control methods can be made to function on the Space Station for up to 1000 days, but that current methods are deficient for periods longer than about 1000 days.

Contamination Control for Thermal Engineers

NASA Technical Reports Server (NTRS)

Rivera, Rachel B.

2015-01-01

The presentation will be given at the 26th Annual Thermal Fluids Analysis Workshop (TFAWS 2015) hosted by the Goddard Spaceflight Center (GSFC) Thermal Engineering Branch (Code 545). This course will cover the basics of Contamination Control, including contamination control related failures, the effects of contamination on Flight Hardware, what contamination requirements translate to, design methodology, and implementing contamination control into Integration, Testing and Launch.

The use of a modified technique to reduce radioactive air contamination in aerosol lung ventilation imaging.

PubMed

Avison, M; Hart, G

2001-06-01

The aim of this study was to reduce airborne contamination resulting from the use of aerosols in lung ventilation scintigraphy. Lung ventilation imaging is frequently performed with 99mTc-diethylenetriaminepentaacetate aerosol (DTPA), derived from a commercial nebuliser. Airborne contamination is a significant problem with this procedure; it results in exposure of staff to radiation and can reduce gamma camera performance when the ventilation is performed in the camera room. We examined the level of airborne contamination resulting from the standard technique with one of the most popular nebuliser kits and tested a modification which significantly reduced airborne contamination. Air contamination was measured while ventilating 122 patients. The modified technique reduced air contamination by a mean value of 64% (p = 0.028) compared with the standard control technique. Additionally, differences in contamination were examined when a mask or mouthpiece was used as well as differences between operators. A simplified method of monitoring air contamination is presented using a commonly available surface contamination monitor. The index so derived was proportional to air contamination (r = 0.88). The problems and regulations associated with airborne contamination are discussed.

Effect of fecal contamination and cross-contamination on numbers of coliform, Escherichia coli, Campylobacter, and Salmonella on immersion-chilled broiler carcasses.

PubMed

Smith, D P; Cason, J A; Berrang, M E

2005-07-01

The effect of prechill fecal contamination on numbers of bacteria on immersion-chilled carcasses was tested in each of three replicate trials. For each trial, 16 eviscerated broiler carcasses were split into 32 halves and assigned to one of two groups. Cecal contents (0.1 g inoculated with Campylobacter and nalidixic acid-resistant Salmonella) were applied to each of eight halves in one group (direct contamination) that were placed into one paddle chiller (contaminated), whereas the other paired halves were placed into another chiller (control). From the second group of eight split birds, one of each paired half was placed in the contaminated chiller (to determine cross-contamination) and the other half was placed in the control chiller. Postchill carcass halves were sampled by a 1-min rinse in sterile water, which was collected and cultured. Bacterial counts were reported as log CFU per milliliter of rinsate. There were no significant statistical differences (paired t test, P < 0.05) from direct contamination for coliforms (mean 3.0 log CFU) and Escherichia coli (mean 2.7 log CFU), although Campylobacter numbers significantly increased from control values because of direct contamination (1.5 versus 2.1 log CFU), and the incidence increased from 79 to 100%. There was no significant effect of cross-contamination on coliform (mean 2.9 log CFU) or E. coli (mean 2.6 log CFU) numbers. Nevertheless, Campylobacter levels were significantly higher after exposure to cross-contamination (1.6 versus 2.0 log CFU), and the incidence of this bacterium increased from 75 to 100%. Salmonella-positive halves increased from 0 to 42% postchill because of direct contamination and from 0 to 25% as a result of cross-contamination after chilling. Water samples and surface swabs taken postchill from the contaminated chiller were higher for Campylobacter than those taken from the control chiller. Immersion chilling equilibrated bacterial numbers between contaminated and control halves subjected to either direct contamination or cross-contamination for coliforms and E. coli. Campylobacter numbers, Campylobacter incidence, and Salmonella incidence increased because of both direct contamination and cross-contamination in the chiller. Postchill E. coli numbers did not indicate which carcass halves were contaminated with feces before chilling.

Semianalytical solutions for contaminant transport under variable velocity field in a coastal aquifer

NASA Astrophysics Data System (ADS)

Koohbor, Behshad; Fahs, Marwan; Ataie-Ashtiani, Behzad; Simmons, Craig T.; Younes, Anis

2018-05-01

Existing closed-form solutions of contaminant transport problems are limited by the mathematically convenient assumption of uniform flow. These solutions cannot be used to investigate contaminant transport in coastal aquifers where seawater intrusion induces a variable velocity field. An adaptation of the Fourier-Galerkin method is introduced to obtain semi-analytical solutions for contaminant transport in a confined coastal aquifer in which the saltwater wedge is in equilibrium with a freshwater discharge flow. Two scenarios dealing with contaminant leakage from the aquifer top surface and contaminant migration from a source at the landward boundary are considered. Robust implementation of the Fourier-Galerkin method is developed to efficiently solve the coupled flow, salt and contaminant transport equations. Various illustrative examples are generated and the semi-analytical solutions are compared against an in-house numerical code. The Fourier series are used to evaluate relevant metrics characterizing contaminant transport such as the discharge flux to the sea, amount of contaminant persisting in the groundwater and solute flux from the source. These metrics represent quantitative data for numerical code validation and are relevant to understand the effect of seawater intrusion on contaminant transport. It is observed that, for the surface contamination scenario, seawater intrusion limits the spread of the contaminant but intensifies the contaminant discharge to the sea. For the landward contamination scenario, moderate seawater intrusion affects only the spatial distribution of the contaminant plume while extreme seawater intrusion can increase the contaminant discharge to the sea. The developed semi-analytical solution presents an efficient tool for the verification of numerical models. It provides a clear interpretation of the contaminant transport processes in coastal aquifers subject to seawater intrusion. For practical usage in further studies, the full open source semi-analytical codes are made available at the website https://lhyges.unistra.fr/FAHS-Marwan.

Design and Testing of Trace Contaminant Injection and Monitoring Systems

NASA Technical Reports Server (NTRS)

Broerman, Craig D.; Sweterlitsch, Jeff

2009-01-01

In support of the Carbon dioxide And Moisture Removal Amine Swing-bed (CAMRAS) testing, a contaminant injection system as well as a contaminant monitoring system has been developed by the Johnson Space Center Air Revitalization Systems (JSC-ARS) team. The contaminant injection system has been designed to provide trace level concentrations of contaminants generated by humans in a closed environment during space flight missions. The contaminant injection system continuously injects contaminants from three gas cylinders, two liquid reservoirs and three permeation ovens. The contaminant monitoring system has been designed to provide real time gas analysis with accurate flow, humidity and gas concentration measurements for collection during test. The contaminant monitoring system consists of an analytical real time gas analyzer, a carbon monoxide sensor, and an analyzer for ammonia and water vapor.

ANALYTICAL METHOD READINESS FOR THE CONTAMINANT CANDIDATE LIST

EPA Science Inventory

The Contaminant Candidate List (CCL), which was promulgated in March 1998, includes 50 chemical and 10 microbiological contaminants/contaminant groups. At the time of promulgation, analytical methods were available for 6 inorganic and 28 organic contaminants. Since then, 4 anal...

Understanding Contamination; Twenty Years of Simulating Radiological Contamination

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

Emily Snyder; John Drake; Ryan James

A wide variety of simulated contamination methods have been developed by researchers to reproducibly test radiological decontamination methods. Some twenty years ago a method of non-radioactive contamination simulation was proposed at the Idaho National Laboratory (INL) that mimicked the character of radioactive cesium and zirconium contamination on stainless steel. It involved baking the contamination into the surface of the stainless steel in order to 'fix' it into a tenacious, tightly bound oxide layer. This type of contamination was particularly applicable to nuclear processing facilities (and nuclear reactors) where oxide growth and exchange of radioactive materials within the oxide layer becamemore » the predominant model for material/contaminant interaction. Additional simulation methods and their empirically derived basis (from a nuclear fuel reprocessing facility) are discussed. In the last ten years the INL, working with the Defense Advanced Research Projects Agency (DARPA) and the National Homeland Security Research Center (NHSRC), has continued to develop contamination simulation methodologies. The most notable of these newer methodologies was developed to compare the efficacy of different decontamination technologies against radiological dispersal device (RDD, 'dirty bomb') type of contamination. There are many different scenarios for how RDD contamination may be spread, but the most commonly used one at the INL involves the dispersal of an aqueous solution containing radioactive Cs-137. This method was chosen during the DARPA projects and has continued through the NHSRC series of decontamination trials and also gives a tenacious 'fixed' contamination. Much has been learned about the interaction of cesium contamination with building materials, particularly concrete, throughout these tests. The effects of porosity, cation-exchange capacity of the material and the amount of dirt and debris on the surface are very important factors. The interaction of the contaminant/substrate with the particular decontamination technology is also very important. Results of decontamination testing from hundreds of contaminated coupons have lead to certain conclusions about the contamination and the type of decontamination methods being deployed. A recent addition to the DARPA initiated methodology simulates the deposition of nuclear fallout. This contamination differs from previous tests in that it has been developed and validated purely to simulate a 'loose' type of contamination. This may represent the first time that a radiologically contaminated 'fallout' stimulant has been developed to reproducibly test decontamination methods. While no contaminant/methodology may serve as a complete example of all aspects that could be seen in the field, the study of this family of simulation methods provides insight into the nature of radiological contamination.« less

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

Detecting and Estimating Contamination of Human DNA Samples in Sequencing and Array-Based Genotype Data

PubMed Central

Jun, Goo; Flickinger, Matthew; Hetrick, Kurt N.; Romm, Jane M.; Doheny, Kimberly F.; Abecasis, Gonçalo R.; Boehnke, Michael; Kang, Hyun Min

2012-01-01

DNA sample contamination is a serious problem in DNA sequencing studies and may result in systematic genotype misclassification and false positive associations. Although methods exist to detect and filter out cross-species contamination, few methods to detect within-species sample contamination are available. In this paper, we describe methods to identify within-species DNA sample contamination based on (1) a combination of sequencing reads and array-based genotype data, (2) sequence reads alone, and (3) array-based genotype data alone. Analysis of sequencing reads allows contamination detection after sequence data is generated but prior to variant calling; analysis of array-based genotype data allows contamination detection prior to generation of costly sequence data. Through a combination of analysis of in silico and experimentally contaminated samples, we show that our methods can reliably detect and estimate levels of contamination as low as 1%. We evaluate the impact of DNA contamination on genotype accuracy and propose effective strategies to screen for and prevent DNA contamination in sequencing studies. PMID:23103226

Resuspended contaminated sediments cause sublethal stress to oysters: A biomarker differentiates total suspended solids and contaminant effects.

PubMed

Edge, Katelyn J; Dafforn, Katherine A; Simpson, Stuart L; Ringwood, Amy H; Johnston, Emma L

2015-06-01

Resuspended contaminated sediments represent an important route of contaminant exposure for aquatic organisms. During resuspension events, filter-feeding organisms are exposed to contaminants, in both the dissolved form (at the gills) and the particulate form (in the digestive system). In addition, these organisms must manage the physical stress associated with an increase in total suspended solids (TSS). To date, few studies have experimentally compared the contributions to biological stress of contaminated and clean suspended solids. The authors mixed field-collected sediments (<63 μm) from clean and contaminated field sites to create 4 treatments of increasing metal concentrations. Sydney rock oysters were then exposed to sediment treatments at different TSS concentrations for 4 d, and cellular biomarkers (lysosomal membrane stability, lipid peroxidation, and glutathione) were measured to evaluate sublethal toxicity. Lysosomal membrane stability was the most sensitive biomarker for distinguishing effects from resuspended contaminated sediments, as increasing amounts of contaminated TSS increased lysosomal membrane destabilization. The authors' results illustrate the importance of considering contaminant exposures from resuspended sediments when assessing the toxicity of contaminants to aquatic organisms. © 2015 SETAC.

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.

Harvesting contaminants from liquid

DOEpatents

Simpson, John T.; Hunter, Scott R.

2016-05-31

Disclosed are examples of apparatuses for evaporative purification of a contaminated liquid. In each example, there is a vessel for storing the contaminated fluid. The vessel includes a surface coated with a layer of superhydrophobic material and the surface is at least partially in contact with the contaminated liquid. The contaminants do not adhere to the surface as the purified liquid evaporates, thus allowing the contaminants to be harvested.

Treatment of Chlorinated Aliphatic Contamination of Groundwater by Horizontal Recirculation Wells and by Constructed Vertical Flow Wetlands

DTIC Science & Technology

2002-03-01

groundwater laden with contaminants. Once the contaminated water is at the surface, it must be treated for contaminant destruction, generally by...treatment walls only work under very specific hydrogeologic conditions (relatively shallow water table, no seasonal fluctuations in groundwater flow...GCWs Elevation Schematic Water Table Contaminated Groundwater Contaminated Groundwater Treated Groundwater Treated Groundwater Reactive Porous Medium

Functional gene diversity of soil microbial communities from five oil-contaminated fields in China.

PubMed

Liang, Yuting; Van Nostrand, Joy D; Deng, Ye; He, Zhili; Wu, Liyou; Zhang, Xu; Li, Guanghe; Zhou, Jizhong

2011-03-01

To compare microbial functional diversity in different oil-contaminated fields and to know the effects of oil contaminant and environmental factors, soil samples were taken from typical oil-contaminated fields located in five geographic regions of China. GeoChip, a high-throughput functional gene array, was used to evaluate the microbial functional genes involved in contaminant degradation and in other major biogeochemical/metabolic processes. Our results indicated that the overall microbial community structures were distinct in each oil-contaminated field, and samples were clustered by geographic locations. The organic contaminant degradation genes were most abundant in all samples and presented a similar pattern under oil contaminant stress among the five fields. In addition, alkane and aromatic hydrocarbon degradation genes such as monooxygenase and dioxygenase were detected in high abundance in the oil-contaminated fields. Canonical correspondence analysis indicated that the microbial functional patterns were highly correlated to the local environmental variables, such as oil contaminant concentration, nitrogen and phosphorus contents, salt and pH. Finally, a total of 59% of microbial community variation from GeoChip data can be explained by oil contamination, geographic location and soil geochemical parameters. This study provided insights into the in situ microbial functional structures in oil-contaminated fields and discerned the linkages between microbial communities and environmental variables, which is important to the application of bioremediation in oil-contaminated sites.

Functional gene diversity of soil microbial communities from five oil-contaminated fields in China

PubMed Central

Liang, Yuting; Van Nostrand, Joy D; Deng, Ye; He, Zhili; Wu, Liyou; Zhang, Xu; Li, Guanghe; Zhou, Jizhong

2011-01-01

To compare microbial functional diversity in different oil-contaminated fields and to know the effects of oil contaminant and environmental factors, soil samples were taken from typical oil-contaminated fields located in five geographic regions of China. GeoChip, a high-throughput functional gene array, was used to evaluate the microbial functional genes involved in contaminant degradation and in other major biogeochemical/metabolic processes. Our results indicated that the overall microbial community structures were distinct in each oil-contaminated field, and samples were clustered by geographic locations. The organic contaminant degradation genes were most abundant in all samples and presented a similar pattern under oil contaminant stress among the five fields. In addition, alkane and aromatic hydrocarbon degradation genes such as monooxygenase and dioxygenase were detected in high abundance in the oil-contaminated fields. Canonical correspondence analysis indicated that the microbial functional patterns were highly correlated to the local environmental variables, such as oil contaminant concentration, nitrogen and phosphorus contents, salt and pH. Finally, a total of 59% of microbial community variation from GeoChip data can be explained by oil contamination, geographic location and soil geochemical parameters. This study provided insights into the in situ microbial functional structures in oil-contaminated fields and discerned the linkages between microbial communities and environmental variables, which is important to the application of bioremediation in oil-contaminated sites. PMID:20861922

Assessing contamination in Great Lakes sediments using benthic invertebrate communities and the sediment quality triad approach

USGS Publications Warehouse

Canfield, Timothy J.; Dwyer, F. James; Fairchild, James F.; Haverland, Pamela S.; Ingersoll, Christopher G.; Kemble, Nile E.; Mount, David R.; La Point, Thomas W.; Burton, G. Allen; Swift, M. C.

1996-01-01

Sediments in many Great Lakes harbors and tributary rivers are contaminated. As part of the USEPA's Assessment and Remediation of Contaminated Sediment (ARCS) program, a number of studies were conducted to determine the nature and extent of sediment contamination in Great Lakes Areas of Concern (AOC). This paper describes the composition of benthic invertebrate communities in contaminated sediments and is one in a series of papers describing studies conducted to evaluate sediment toxicity from three AOC's (Buffalo River, NY; Indiana Harbor, IN; Saginaw River, MI), as part of the ARCS Program. Oligochaeta (worms) and Chironomidae (midge) comprised over 90% of the benthic invertebrate numbers in samples collected from depositional areas. Worms and midge consisted of taxa identified as primarily contaminant tolerant organisms. Structural deformities of mouthparts in midge larvae were pronounced in many of the samples. Good concurrence was evident between measures of laboratory toxicity, sediment contaminant concentration, and benthic invertebrate community composition in extremely contaminated samples. However, in moderately contaminated samples, less concordance was observed between the benthos community composition and either laboratory toxicity test results or sediment contaminant concentration. Laboratory sediment toxicity tests may better identify chemical contamination in sediments than many commonly used measures of benthic invertebrate community composition. Benthic measures may also reflect other factors such as habitat alteration. Evaluation of non-contaminant factors are needed to better interpret the response of benthic invertebrates to sediment contamination.

Verification approach for the Shuttle/Payload Contamination Evaluation computer program - Spacelab induced environment

NASA Technical Reports Server (NTRS)

Bareiss, L. E.

1978-01-01

The paper presents a compilation of the results of a systems level Shuttle/payload contamination analysis and related computer modeling activities. The current technical assessment of the contamination problems anticipated during the Spacelab program are discussed and recommendations are presented on contamination abatement designs and operational procedures based on experience gained in the field of contamination analysis and assessment, dating back to the pre-Skylab era. The ultimate test of the Shuttle/Payload Contamination Evaluation program will be through comparison of predictions with measured levels of contamination during actual flight.

Environmental Variation in Contamination Outgas Testing of a Composite Material

DTIC Science & Technology

2009-03-15

outgassed by Sample 1 on QCM 1 (233K) 8 4. Deposition of contaminants outgassed by Sample 1 on QCM 2 (113K) 8 5. Deposition of contaminants...outgassed by Sample 2 on QCM 1 (233K) 10 6. Deposition of contaminants outgassed by Sample 2 on QCM 2 (113K) 10 7. Deposition of contaminants outgassed by...Sample 3 on QCM 1 (233K) 12 8. Deposition of contaminants outgassed by Sample 3 on QCM 2 (113K) 12 9. Deposition of contaminants outgassed by

Method for remote detection of trace contaminants

DOEpatents

Simonson, Robert J.; Hance, Bradley G.

2003-09-09

A method for remote detection of trace contaminants in a target area comprises applying sensor particles that preconcentrate the trace contaminant to the target area and detecting the contaminant-sensitive fluorescence from the sensor particles. The sensor particles can have contaminant-sensitive and contaminant-insensitive fluorescent compounds to enable the determination of the amount of trace contaminant present in the target are by relative comparison of the emission of the fluorescent compounds by a local or remote fluorescence detector. The method can be used to remotely detect buried minefields.

Organizational strategies for protection against back contamination

NASA Technical Reports Server (NTRS)

Mahoney, T. A.

1976-01-01

The organizational issues pertaining to the prevention of inbound contamination associated with possible Viking missions to Mars are considered. The completed Apollo missions, which returned samples from the moon, provide a convenient base for analysis of inbound contamination issues. Despite concern over the threat of inbound contamination from the moon and efforts to prevent back contamination, the back contamination efforts in the Apollo missions were considered ineffective had these missions encountered living organisms. Several alternatives for consideration in the design of future programs dealing with back contamination are examined and proposed for special consideration.

Standardization of Rocket Engine Pulse Time Parameters

NASA Technical Reports Server (NTRS)

Larin, Max E.; Lumpkin, Forrest E.; Rauer, Scott J.

2001-01-01

Plumes of bipropellant thrusters are a source of contamination. Small bipropellant thrusters are often used for spacecraft attitude control and orbit correction. Such thrusters typically operate in a pulse mode, at various pulse lengths. Quantifying their contamination effects onto spacecraft external surfaces is especially important for long-term complex-geometry vehicles, e.g. International Space Station. Plume contamination tests indicated the presence of liquid phase contaminant in the form of droplets. Their origin is attributed to incomplete combustion. Most of liquid-phase contaminant is generated during the startup and shutdown (unsteady) periods of thruster pulse. These periods are relatively short (typically 10-50 ms), and the amount of contaminant is determined by the thruster design (propellant valve response, combustion chamber size, thruster mass flow rate, film cooling percentage, dribble volume, etc.) and combustion process organization. Steady-state period of pulse is characterized by much lower contamination rates, but may be lengthy enough to significantly conh'ibute to the overall contamination effect. Because there was no standard methodology for thruster pulse time division, plume contamination tests were conducted at various pulse durations, and their results do not allow quantifying contaminant amounts from each portion of the pulse. At present, the ISS plume contamination model uses an assumption that all thrusters operate in a pulse mode with the pulse length being 100 ms. This assumption may lead to a large difference between the actual amounts of contaminant produced by the thruster and the model predictions. This paper suggests a way to standardize thruster startup and shutdown period definitions, and shows the usefulness of this approach to better quantify thruster plume contamination. Use of the suggested thruster pulse time-division technique will ensure methodological consistency of future thruster plume contamination test programs, and allow accounting for thruster pulse length when modeling plume contamination and erosion effects.

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.

A review of what is an emerging contaminant

PubMed Central

2014-01-01

A review is presented of how one defines emerging contaminants and what can be included in that group of contaminants which is preferably termed “contaminants of emerging concern”. An historical perspective is given on the evolution of the issues surrounding emerging contaminants and how environmental scientists have tackled this issue. This begins with global lead contamination from the Romans two millennia ago, moves on to arsenic-based and DDT issues and more recently to pharmaceuticals, cyanotoxins, personal care products, nanoparticles, flame retardants, etc. Contaminants of emerging concern will remain a moving target as new chemical compounds are continuously being produced and science continuously improves its understanding of current and past contaminants. PMID:24572188

Enhancement of in situ microbial remediation of aquifers

DOEpatents

Fredrickson, James K.; Brockman, Fred J.; Streile, Gary P.; Cary, John W.; McBride, John F.

1993-01-01

Methods are provided for remediating subsurface areas contaminated by toxic organic compounds. An innocuous oil, such as vegetable oil, mineral oil, or other immiscible organic liquid, is introduced into the contaminated area and permitted to move therethrough. The oil concentrates or strips the organic contaminants, such that the concentration of the contaminants is reduced and such contaminants are available to be either pumped out of the subsurface area or metabolized by microorganisms. Microorganisms may be introduced into the contaminated area to effect bioremediation of the contamination. The methods may be adapted to deliver microorganisms, enzymes, nutrients and electron donors to subsurface zones contaminated by nitrate in order to stimulate or enhance denitrification.

Enhancement of in situ microbial remediation of aquifers

DOEpatents

Fredrickson, J.K.; Brockman, F.J.; Streile, G.P.; Cary, J.W.; McBride, J.F.

1993-11-30

Methods are provided for remediating subsurface areas contaminated by toxic organic compounds. An innocuous oil, such as vegetable oil, mineral oil, or other immiscible organic liquid, is introduced into the contaminated area and permitted to move therethrough. The oil concentrates or strips the organic contaminants, such that the concentration of the contaminants is reduced and such contaminants are available to be either pumped out of the subsurface area or metabolized by microorganisms. Microorganisms may be introduced into the contaminated area to effect bioremediation of the contamination. The methods may be adapted to deliver microorganisms, enzymes, nutrients and electron donors to subsurface zones contaminated by nitrate in order to stimulate or enhance denitrification. 4 figures.

Armored Enzyme Nanoparticles for Remediation of Subsurface

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

Grate, Jay W.

2005-09-01

The remediation of subsurface contaminants is a critical problem for the Department of Energy, other government agencies, and our nation. Severe contamination of soil and groundwater exists at several DOE sites due to various methods of intentional and unintentional release. Given the difficulties involved in conventional removal or separation processes, it is vital to develop methods to transform contaminants and contaminated earth/water to reduce risks to human health and the environment. Transformation of the contaminants themselves may involve conversion to other immobile species that do not migrate into well water or surface waters, as is proposed for metals and radionuclides;more » or degradation to harmless molecules, as is desired for organic contaminants. Transformation of contaminated earth (as opposed to the contaminants themselves) may entail reductions in volume or release of bound contaminants for remediation.« less

Applying Contamination Modelling to Spacecraft Propulsion Systems Designs and Operations

NASA Technical Reports Server (NTRS)

Chen, Philip T.; Thomson, Shaun; Woronowicz, Michael S.

2000-01-01

Molecular and particulate contaminants generated from the operations of a propulsion system may impinge on spacecraft critical surfaces. Plume depositions or clouds may hinder the spacecraft and instruments from performing normal operations. Firing thrusters will generate both molecular and particulate contaminants. How to minimize the contamination impact from the plume becomes very critical for a successful mission. The resulting effect from either molecular or particulate contamination of the thruster firing is very distinct. This paper will discuss the interconnection between the functions of spacecraft contamination modeling and propulsion system implementation. The paper will address an innovative contamination engineering approach implemented from the spacecraft concept design, manufacturing, integration and test (I&T), launch, to on- orbit operations. This paper will also summarize the implementation on several successful missions. Despite other contamination sources, only molecular contamination will be considered here.

Karst hydrology and chemical contamination

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

Field, M.S.

1993-01-01

Ground-water flow in karst aquifers is very different from flow in granular or fractured aquifers. Chemical contamination may be fed directly to a karst aquifer via overland flow to a sinkhole with little or no attenuation and may contaminate downgradient wells, springs, and sinkholes within a few hours or a few days. Contaminants may also become temporarily stored in the epikarstic zone for eventual release to the aquifer. Flood pulses may flush the contaminants to cause transiently higher levels of contamination in the aquifer and discharge points. The convergent nature of flow in karst aquifers may result in contaminants becomingmore » concentrated in conduits. Once contaminants have reached the subsurface conduits, they are likely to be rapidly transported to spring outlets. Traditional aquifer remediation techniques for contaminated aquifers are less applicable to karst aquifers.« less

Fluorescence Imaging Reveals Surface Contamination

NASA Technical Reports Server (NTRS)

Schirato, Richard; Polichar, Raulf

1992-01-01

In technique to detect surface contamination, object inspected illuminated by ultraviolet light to make contaminants fluoresce; low-light-level video camera views fluorescence. Image-processing techniques quantify distribution of contaminants. If fluorescence of material expected to contaminate surface is not intense, tagged with low concentration of dye.

40 CFR 141.50 - Maximum contaminant level goals for organic contaminants.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Maximum contaminant level goals for organic contaminants. 141.50 Section 141.50 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Maximum Contaminant Level...

Mir Contamination Observations and Implications to the International Space Station

NASA Technical Reports Server (NTRS)

Soares, Carlos; Mikatarian, Ron

2000-01-01

A series of external contamination measurements were made on the Russian Mir Space Station. The Mir external contamination observations summarized in this paper were essential in assessing the system level impact of Russian Segment induced contamination on the International Space Station (ISS). Mir contamination observations include results from a series of flight experiments: CNES Comes-Aragatz, retrieved NASA camera bracket, Euro-Mir '95 ICA, retrieved NASA Trek blanket, Russian Astra-II, Mir Solar Array Return Experiment (SARE), etc. Results from these experiments were studied in detail to characterize Mir induced contamination. In conjunction with Mir contamination observations, Russian materials samples were tested for condensable outgassing rates in the U.S. These test results were essential in the characterization of Mir contamination sources. Once Mir contamination sources were identified and characterized, activities to assess the implications to ISS were implemented. As a result, modifications in Russian materials selection and/or usage were implemented to control contamination and mitigate risk to ISS.

Post-Contamination Vapour Hazards from Military Vehicles Contaminated with Thickened and Unthickened GD

DTIC Science & Technology

1979-02-01

The residual vapour hazards from four types of military vehicles previously contaminated with either thickened or unthickened GD have been measured...magnitude of these hazards have been investigated and an assessment made of their relevance to contamination control. It was found that on permeable... contamination had been applied were ineffective in reducing the subsequent vapour hazard; the vapour hazard arising from thickened GD contamination was less

Influence of contaminant burial depth on the bioaccumulation of PCBs and PBDEs by two benthic invertebrates (Monoporeia affinis and Marenzelleria spp.).

PubMed

Josefsson, Sarah; Leonardsson, Kjell; Gunnarsson, Jonas S; Wiberg, Karin

2011-11-01

The bioaccumulation of buried polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) added to specific depths in sediment (2.0-2.5, 5.0-5.5 and 10.0-10.5cm) was studied in two infaunal species with similar feeding habits (surface deposit-feeders) but different bioturbation modes. The deep-burrowing polychaetes Marenzelleria spp. (Mz) displayed up to 36 times higher tissue concentrations of buried (spiked) contaminants than the surface-dwelling biodiffusing amphipod Monoporeia affinis. The differences in bioaccumulation were most pronounced for less hydrophobic contaminants due to the bioirrigating activity of Mz. Contaminants buried at shallow depths displayed higher accumulation than more deeply buried contaminants. In contrast, the bioaccumulation of unspiked (native) contaminants with a uniform vertical distribution in the sediment was similar between the species. For Mz, the BSAFs increased with increased K(OW) for the uniformly distributed contaminants, but decreased for the buried contaminants, which indicates that the dominant uptake routes of the buried contaminants can differ from the uniformly distributed contaminants. The surface sediment concentration of buried contaminants increased in Mz treatments, showing that Mz bioturbation can remobilize historically buried contaminants to the biologically active surface layer and increase the exposure for surface-dwelling species. Copyright © 2011 Elsevier Ltd. All rights reserved.

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

Development of RadRob15, A Robot for Detecting Radioactive Contamination in Nuclear Medicine Departments.

PubMed

Shafe, A; Mortazavi, S M J; Joharnia, A; Safaeyan, Gh H

2016-09-01

Accidental or intentional release of radioactive materials into the living or working environment may cause radioactive contamination. In nuclear medicine departments, radioactive contamination is usually due to radionuclides which emit high energy gamma photons and particles. These radionuclides have a broad range of energies and penetration capabilities. Rapid detection of radioactive contamination is very important for efficient removing of the contamination without spreading the radionuclides. A quick scan of the contaminated area helps health physicists locate the contaminated area and assess the level of activity. Studies performed in IR Iran shows that in some nuclear medicine departments, areas with relatively high levels of activity can be found. The highest contamination level was detected in corridors which are usually used by patients. To monitor radioactive contamination in nuclear medicine departments, RadRob15, a contamination detecting robot was developed in the Ionizing and Non-ionizing Radiation Protection Research Center (INIRPRC). The motor vehicle scanner and the gas radiation detector are the main components of this robot. The detection limit of this robot has enabled it to detect low levels of radioactive contamination. Our preliminary tests show that RadRob15 can be easily used in nuclear medicine departments as a device for quick surveys which identifies the presence or absence of radioactive contamination.

Factors influencing the contamination rate of human organ-cultured corneas.

PubMed

Röck, Daniel; Wude, Johanna; Bartz-Schmidt, Karl U; Yoeruek, Efdal; Thaler, Sebastian; Röck, Tobias

2017-12-01

To assess the influence of donor, environment and storage factors on the contamination rate of organ-cultured corneas, to consider the microbiological species causing corneal contamination and to investigate the corresponding sensitivities. Data from 1340 consecutive donor corneas were analysed retrospectively. Logistic regression analysis was used to assess the influence of different factors on the contamination rate of organ-cultured corneas for transplantation. The mean annual contamination rate was 1.8 ± 0.4% (range: 1.3-2.1%); 50% contaminations were of fungal origin with exclusively Candida species, and 50% contaminations were of bacterial origin with Staphylococcus species being predominant. The cause of donor death including infection and multiple organ dysfunction syndrome increased the risk of bacterial or fungal contamination during organ culture (p = 0.007 and p = 0.014, respectively). Differentiating between septic and aseptic donors showed an increased risk of contamination for septic donors (p = 0.0020). Mean monthly temperature including warmer months increased the risk of contamination significantly (p = 0.0031). Sex, donor age, death to enucleation, death to corneoscleral disc excision and storage time did not increase the risk of contamination significantly. The genesis of microbial contamination in organ-cultured donor corneas seems to be multifactorial. The main source of fungal or bacterial contamination could be resident species from the skin flora. The rate of microbial contamination in organ-cultured donor corneas seems to be dependent on the cause of donor death and mean monthly temperature. © 2017 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Challenging a bioinformatic tool's ability to detect microbial contaminants using in silico whole genome sequencing data.

PubMed

Olson, Nathan D; Zook, Justin M; Morrow, Jayne B; Lin, Nancy J

2017-01-01

High sensitivity methods such as next generation sequencing and polymerase chain reaction (PCR) are adversely impacted by organismal and DNA contaminants. Current methods for detecting contaminants in microbial materials (genomic DNA and cultures) are not sensitive enough and require either a known or culturable contaminant. Whole genome sequencing (WGS) is a promising approach for detecting contaminants due to its sensitivity and lack of need for a priori assumptions about the contaminant. Prior to applying WGS, we must first understand its limitations for detecting contaminants and potential for false positives. Herein we demonstrate and characterize a WGS-based approach to detect organismal contaminants using an existing metagenomic taxonomic classification algorithm. Simulated WGS datasets from ten genera as individuals and binary mixtures of eight organisms at varying ratios were analyzed to evaluate the role of contaminant concentration and taxonomy on detection. For the individual genomes the false positive contaminants reported depended on the genus, with Staphylococcus , Escherichia , and Shigella having the highest proportion of false positives. For nearly all binary mixtures the contaminant was detected in the in-silico datasets at the equivalent of 1 in 1,000 cells, though F. tularensis was not detected in any of the simulated contaminant mixtures and Y. pestis was only detected at the equivalent of one in 10 cells. Once a WGS method for detecting contaminants is characterized, it can be applied to evaluate microbial material purity, in efforts to ensure that contaminants are characterized in microbial materials used to validate pathogen detection assays, generate genome assemblies for database submission, and benchmark sequencing methods.

30 CFR 57.5005 - Control of exposure to airborne contaminants.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Control of exposure to airborne contaminants... Underground § 57.5005 Control of exposure to airborne contaminants. Control of employee exposure to harmful airborne contaminants shall be, insofar as feasible, by prevention of contamination, removal by exhaust...

Contamination control in hybrid microelectronic modules. Identification of critical process and contaminants, part 1

NASA Technical Reports Server (NTRS)

Himmel, R. P.

1975-01-01

Hybrid processes, handling procedures, and materials were examined to identify the critical process steps in which contamination is most likely to occur, to identify the particular contaminants associated with these critical steps, and to propose method for the control of these contaminants.

LONG-TERM RECOVERY OF PCB-CONTAMINATED SURFACE SEDIMENTS AT THE SANGAMO-WESTON/TWELVEMILE CREEK/LAKE HARTWELL SUPERFUND SITE

EPA Science Inventory

Natural recovery of contaminated sediments relies on burial of contaminated sediments with increasingly clean sediments over time (i.e., natural capping). Natural capping reduces the risk of resuspension of contaminated surface sediments, and it reduces the potential for contamin...

Lessons Learned from the Hubble Space Telescope (HST) Contamination Control Program

NASA Technical Reports Server (NTRS)

Hansen, Patricia A.; Townsend, Jacqueline A.; Hedgeland, Randy J.

2004-01-01

Over the past two decades, the Hubble Space Telescope (HST) Contamination Control Program has evolved from a ground-based integration program to a space-based science-sustaining program. The contamination controls from the new-generation Scientific Instruments and Orbital Replacement Units were incorporated into the HST Contamination Control Program to maintain scientific capability over the life of the telescope. Long-term on-orbit scientific data has shown that these contamination controls implemented for the instruments, Servicing Mission activities (Orbiter, Astronauts, and mission), and on-orbit operations successfully protected the HST &om contamination and the instruments from self-contamination.

Lessons Learned from the Hubble Space Telescope (HST) Contamination Control Program

NASA Technical Reports Server (NTRS)

Hansen, Patricia A.; Townsend, Jacqueline A.; Hedgeland, Randy J.

2004-01-01

Over the past two decades, the Hubble Space Telescope (HST) Contamination Control Program has evolved from a ground-based integration program to a space-based science-sustaining program. The contamination controls from the new-generation Scientific Instruments and Orbital Replacement Units were incorporated into the HST Contamination Control Program to maintain scientific capability over the life of the telescope. Long-term on-orbit scientific data has shown that these contamination controls implemented for the instruments, Servicing Mission activities (Orbiter, Astronauts, and mission), and on-orbit operations successfully protected the HST from contamination and the instruments from self-contamination.

An overview of the on-orbit contamination of the Long Duration Exposure Facility (LDEF)

NASA Technical Reports Server (NTRS)

Stuckey, W. K.

1993-01-01

Contamination that leads to degradation of critical surfaces becomes a vital design issue for many spacecraft programs. One of the processes that must be considered is the on-orbit accumulation of contaminants. The Long Duration Exposure Facility (LDEF) has presented an opportunity to examine the deposits on surfaces returned from orbit in order to help in understanding the deposition processes and the current models used to predict spacecraft contamination levels. The results from various investigators on the contamination of LDEF have implications for material selection, contamination models, and contamination control plans for the design of future spacecraft.

Biological Remediation of Petroleum Contaminants

NASA Astrophysics Data System (ADS)

Kuhad, Ramesh Chander; Gupta, Rishi

Large volumes of hazardous wastes are generated in the form of oily sludges and contaminated soils during crude oil transportation and processing. Although many physical, chemical and biological treatment technologies are available for petroleum contaminants petroleum contaminants in soil, biological methods have been considered the most cost-effective. Practical biological remediation methods typically involve direct use of the microbes naturally occurring in the contaminated environment and/or cultured indigenous or modified microorganisms. Environmental and nutritional factors, including the properties of the soil, the chemical structure of the hydrocarbon(s), oxygen, water, nutrient availability, pH, temperature, and contaminant bioavailability, can significantly affect the rate and the extent of hydrocarbon biodegradation hydrocarbon biodegradation by microorganisms in contaminated soils. This chapter concisely discusses the major aspects of bioremediation of petroleum contaminants.

Method of removing oxidized contaminants from water

DOEpatents

Amonette, James E.; Fruchter, Jonathan S.; Gorby, Yuri A.; Cole, Charles R.; Cantrell, Kirk J.; Kaplan, Daniel I.

1998-01-01

The present invention is a method for removing oxidized contaminant(s) from water. More specifically, the invention has the steps of contacting water containing the oxidized contaminant(s) with a layered aluminosilicate having Fe(II). The aluminosilicate may contain naturally occurring Fe(II), or the Fe(II) may be produced by reducing Fe(III) that is initially present. Reduction may be either by exposure to a chemical or biological reductant. Contacting the water containing oxidized contaminant(s) may be by (1) injection of Fe(II)-containing layered aluminosilicate, via a well, into a saturated zone where it is likely to intercept the contaminated water; (2) injection of contaminated water into a vessel containing the Fe(II)-bearing layered aluminosilicate; and (3) first reducing Fe(III) in the layered aluminosilicate to Fe(II) by injection of a biological or chemical reductant, into an aquifer or vessel having sufficient Fe(III)-bearing aluminosilicate to produce the necessary Fe(II).

Method of removing oxidized contaminants from water

DOEpatents

Amonette, J.E.; Fruchter, J.S.; Gorby, Y.A.; Cole, C.R.; Cantrell, K.J.; Kaplan, D.I.

1998-07-21

The present invention is a method for removing oxidized contaminant(s) from water. More specifically, the invention has the steps of contacting water containing the oxidized contaminant(s) with a layered aluminosilicate having Fe(II). The aluminosilicate may contain naturally occurring Fe(II), or the Fe(II) may be produced by reducing Fe(III) that is initially present. Reduction may be either by exposure to a chemical or biological reductant. Contacting the water containing oxidized contaminant(s) may be by (1) injection of Fe(II)-containing layered aluminosilicate, via a well, into a saturated zone where it is likely to intercept the contaminated water; (2) injection of contaminated water into a vessel containing the Fe(II)-bearing layered aluminosilicate; and (3) first reducing Fe(III) in the layered aluminosilicate to Fe(II) by injection of a biological or chemical reductant, into an aquifer or vessel having sufficient Fe(III)-bearing aluminosilicate to produce the necessary Fe(II). 8 figs.

Induced Contamination Predictions for JAXA's MPAC&SEED Devices

NASA Technical Reports Server (NTRS)

Steagall, Courtney; Smith, Kendall; Huang, Alvin; Soares, Carlos; Mikatarian, Ron

2008-01-01

Externally mounted ISS payloads are exposed to the induced ISS environment, including material outgassing and thruster plume contamination. The Boeing Space Environments Team developed analytical and semiempirical models to predict material outgassing and thruster plume induced contamination. JAXA s SM/MPAC&SEED experiment provides an unique opportunity to compare induced contamination predications with measurements. Analysis results are qualitatively consistent with XPS measurements. Calculated depth of contamination within a factor of 2-3 of measured contamination. Represents extremely good agreement, especially considering long duration of experiment and number of outgassing sources. Despite XPS limitations in quantifying plume contamination, the measured and predicted results are of similar scale for the wake-facing surfaces. JAXA s JEM/MPAC&SEED experiment will also be exposed to induced contamination due to JEM and ISS hardware. Predicted material outgassing induced contamination to JEM/MPAC&SEED ranges from 44 to 262 (depending on surface temperature) for a 3 year exposure duration.

MSFC Skylab contamination control systems mission evaluation

NASA Technical Reports Server (NTRS)

1974-01-01

Cluster external contamination control evaluation was made throughout the Skylab Mission. This evaluation indicated that contamination control measures instigated during the design, development, and operational phases of this program were adequate to reduce the general contamination environment external to the Cluster below the threshold senstivity levels for experiments and affected subsystems. Launch and orbit contamination control features included eliminating certain vents, rerouting vents for minimum contamination impact, establishing filters, incorporating materials with minimum outgassing characteristics and developing operational constraints and mission rules to minimize contamination effects. Prior to the launch of Skylab, contamination control math models were developed which were used to predict Cluster surface deposition and background brightness levels throughout the mission. The report summarizes the Skylab system and experiment contamination control evaluation. The Cluster systems and experiments evaluated include Induced Atmosphere, Corollary and ATM Experiments, Thermal Control Surfaces, Solar Array Systems, Windows and Star Tracker.

Trends in blood culture contamination: a College of American Pathologists Q-Tracks study of 356 institutions.

PubMed

Bekeris, Leonas G; Tworek, Joseph A; Walsh, Molly K; Valenstein, Paul N

2005-10-01

Blood culture contamination extends hospital stays and increases the cost of care. To measure blood culture contamination rates in a large number of institutions over time and to elucidate practice patterns and demographic factors associated with sustained reduction in contamination rates. Longitudinal cohort study of 356 clinical laboratories that provided quarterly data about blood culture results, using a uniform definition of contamination. Mixed linear model analysis of the 1999 through 2003 data set. Blood culture contamination was significantly higher in institutions that used nonlaboratory personnel to collect blood (P = .03) and significantly lower in facilities that used a dedicated phlebotomy team (P < .001). Higher volume of blood collection was significantly associated with lower contamination rates (P < .001). Continued participation in the Q-Tracks monitoring program was associated with significant and progressive reduction in contamination rates. By the fifth year of participation, the median institution had reduced its blood culture contamination rate by 0.67% (P < .001). Institutions that use decentralized patient-centered personnel rather than dedicated phlebotomy teams to collect blood cultures experience significantly higher contamination rates. Long-term monitoring of contamination is associated with sustained improvement in performance.

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.

Tolerance of negative emotion moderates the amplification of mental contamination following an evoking task: A randomized experimental study.

PubMed

Fergus, Thomas A

2018-06-01

Contamination is a near universal feeling, with mental contamination representing a contamination feeling in the absence of direct physical contact with a source. Extant research indicates that tolerance of negative emotion is important for understanding emotional reactions to images, thoughts, and memories, all of which are common sources of mental contamination. Extending research linking distress tolerance to mental contamination, this study examined if individual differences in the tolerance of negative emotion moderates the amplification of mental contamination following an evoking task. Unselected participants completed a self-report measure of tolerance of negative emotion during an online session. They later attended an in-person session and were randomized to an experimental scenario group: betrayal (n = 49) or control (n = 49). Participants imagined themselves in a scenario, with the betrayal scenario designed to evoke mental contamination. Mental contamination was assessed by self-report before and after the scenario. The betrayal, but not control, scenario caused an increase in mental contamination. Tolerance for negative emotion moderated the effect of group on mental contamination. Group differences in mental contamination evidenced at low, but not high, distress tolerance. A novel experimental manipulation and an unselected sample were used. Future research could assess tolerance of negative emotion using a behavioral task. These results indicate that tolerance of negative emotion may be important for understanding when individuals experience mental contamination. Copyright © 2017 Elsevier Ltd. All rights reserved.

Estimated association between dwelling soil contamination and internal radiation contamination levels after the 2011 Fukushima Daiichi nuclear accident in Japan

PubMed Central

Tsubokura, Masaharu; Nomura, Shuhei; Sakaihara, Kikugoro; Kato, Shigeaki; Leppold, Claire; Furutani, Tomoyuki; Morita, Tomohiro; Oikawa, Tomoyoshi; Kanazawa, Yukio

2016-01-01

Objectives Measurement of soil contamination levels has been considered a feasible method for dose estimation of internal radiation exposure following the Chernobyl disaster by means of aggregate transfer factors; however, it is still unclear whether the estimation of internal contamination based on soil contamination levels is universally valid or incident specific. Methods To address this issue, we evaluated relationships between in vivo and soil cesium-137 (Cs-137) contamination using data on internal contamination levels among Minamisoma (10–40 km north from the Fukushima Daiichi nuclear power plant), Fukushima residents 2–3 years following the disaster, and constructed three models for statistical analysis based on continuous and categorical (equal intervals and quantiles) soil contamination levels. Results A total of 7987 people with a mean age of 55.4 years underwent screening of in vivo Cs-137 whole-body counting. A statistically significant association was noted between internal and continuous Cs-137 soil contamination levels (model 1, p value <0.001), although the association was slight (relative risk (RR): 1.03 per 10 kBq/m2 increase in soil contamination). Analysis of categorical soil contamination levels showed statistical (but not clinical) significance only in relatively higher soil contamination levels (model 2: Cs-137 levels above 100 kBq/m2 compared to those <25 kBq/m2, RR=1.75, p value <0.01; model 3: levels above 63 kBq/m2 compared to those <11 kBq/m2, RR=1.45, p value <0.05). Conclusions Low levels of internal and soil contamination were not associated, and only loose/small associations were observed in areas with slightly higher levels of soil contamination in Fukushima, representing a clear difference from the strong associations found in post-disaster Chernobyl. These results indicate that soil contamination levels generally do not contribute to the internal contamination of residents in Fukushima; thus, individual measurements are essential for the precise evaluation of chronic internal radiation contamination. PMID:27357196

Polychlorinated biphenyl (PCB) contamination in Galveston Bay, Texas: Comparing concentrations and profiles in sediments, passive samplers, and fish.

PubMed

Oziolor, Elias M; Apell, Jennifer N; Winfield, Zach C; Back, Jeffrey A; Usenko, Sascha; Matson, Cole W

2018-05-01

The industrialized portion of the Houston Ship Channel (HSC) is heavily contaminated with anthropogenic contaminants, most prominent of which are the polychlorinated biphenyls (PCBs). This contamination has driven adaptive evolution in a keystone species for Galveston Bay, the Gulf killifish (Fundulus grandis). We investigated the geographical extent of PCB impacts by sampling 12 sites, ranging from the heavily industrialized upper portion of the HSC to Galveston Island. At each site, PCB concentrations and profiles were determined in three environmental compartments: sediment, water (polyethylene passive samplers), and fish tissue (resident Gulf killifish). We observed a steep gradient of PCB contamination, ranging from 4.00 to 100,000 ng/g organic carbon in sediment, 290-110,000 ng/g lipid in fish, and 4.5-2300 ng/g polyethylene in passive samplers. The PCB congener profiles in Gulf killifish at the most heavily contaminated sites were shifted toward the higher chlorinated PCBs and were highly similar to the sediment contamination profiles. In addition, while magnitude of total PCB concentrations in sediment and total fish contamination levels were highly correlated between sites, the relative PCB congener profiles in fish and passive samplers were more alike. This strong correlation, along with a lack of dependency of biota-sediment accumulation factors with total contamination rates, confirm the likely non-migratory nature of Gulf killifish and suggest their contamination levels are a good site-specific indicator of contamination in the Galveston Bay area. The spatial gradient of PCB contamination in Galveston Bay was evident in all three matrices studied and was observed effectively using Gulf killifish contamination as an environmentally relevant bioindicator of localized contamination in this environment. Copyright © 2018 Elsevier Ltd. All rights reserved.

Correlation of Spatio-Temporal Contaminant Distribution, Land Use, and Hydrogeological Factors in the Karst Aquifers of Northern Puerto Rico

NASA Astrophysics Data System (ADS)

Torres Torres, N. I.; Padilla, I. Y.

2015-12-01

Karst aquifers are characterized by caves, springs, and sinkholes, and typified by interconnected fissures, fractures and conduits. These characteristics make these aquifers highly productive, and vulnerable to contamination. Previous studies in the northern karst aquifers of Puerto Rico have shown significant distribution of contaminants, including volatile organic compounds, phthalates and other contaminants of emerging concern, beyond demarked sources of contamination. This study develops spatial-temporal distributions of phthalate contaminants in the karst system of northern Puerto Rico and assesses statistical correlations between hydrogeologic factors and groundwater contamination with phthalates. Geographic Information Systems (GIS) tools and technologies, and statistical models are applied to attain these objectives. Results show that there is an extensive contamination with phthalates that varies with time. Contamination is present in the confined and shallow aquifers. Di-(2-ethylhexyl) phthalate (DEHP) is the most detected contaminant (20.6% of the sites). Diethyl phthalate and and dibutyl phthalate are also detected in 6.7% and 8.24% of the sites, respectively. Phthalates detected as mixtures components are significantly detected in areas of high urban and industrial development. They are also detected in areas within 5 miles of superfund sites and landfills. The results indicate that phthalate contamination is highly related to land use. Statistical models show that the hydraulic conductivity of the aquifers, sinkholes density, and time are significantly related to the presence of phthalates in groundwater. The extensive spatio-temporal contamination suggests that contaminants can persist in the environment for long periods of time, and that land use and hydrogeological factors are important factors contributing to the presence of emerging contaminants in karst systems.

Challenging a bioinformatic tool’s ability to detect microbial contaminants using in silico whole genome sequencing data

PubMed Central

Zook, Justin M.; Morrow, Jayne B.; Lin, Nancy J.

2017-01-01

High sensitivity methods such as next generation sequencing and polymerase chain reaction (PCR) are adversely impacted by organismal and DNA contaminants. Current methods for detecting contaminants in microbial materials (genomic DNA and cultures) are not sensitive enough and require either a known or culturable contaminant. Whole genome sequencing (WGS) is a promising approach for detecting contaminants due to its sensitivity and lack of need for a priori assumptions about the contaminant. Prior to applying WGS, we must first understand its limitations for detecting contaminants and potential for false positives. Herein we demonstrate and characterize a WGS-based approach to detect organismal contaminants using an existing metagenomic taxonomic classification algorithm. Simulated WGS datasets from ten genera as individuals and binary mixtures of eight organisms at varying ratios were analyzed to evaluate the role of contaminant concentration and taxonomy on detection. For the individual genomes the false positive contaminants reported depended on the genus, with Staphylococcus, Escherichia, and Shigella having the highest proportion of false positives. For nearly all binary mixtures the contaminant was detected in the in-silico datasets at the equivalent of 1 in 1,000 cells, though F. tularensis was not detected in any of the simulated contaminant mixtures and Y. pestis was only detected at the equivalent of one in 10 cells. Once a WGS method for detecting contaminants is characterized, it can be applied to evaluate microbial material purity, in efforts to ensure that contaminants are characterized in microbial materials used to validate pathogen detection assays, generate genome assemblies for database submission, and benchmark sequencing methods. PMID:28924496

Inorganic and organic contaminants in Alaskan shorebird eggs.

PubMed

Saalfeld, David T; Matz, Angela C; McCaffery, Brian J; Johnson, Oscar W; Bruner, Phil; Lanctot, Richard B

2016-05-01

Many shorebird populations throughout North America are thought to be declining, with potential causes attributed to habitat loss and fragmentation, reduced prey availability, increased predation, human disturbance, and increased exposure to environmental pollutants. Shorebirds may be particularly vulnerable to contaminant exposure throughout their life cycle, as they forage primarily on invertebrates in wetlands, where many contaminants accumulate disproportionately in the sediments. Therefore, it is important to document and monitor shorebird populations thought to be at risk and assess the role that environmental contaminants may have on population declines. To investigate potential threats and provide baseline data on shorebird contaminant levels in Alaskan shorebirds, contaminant concentrations were evaluated in shorebird eggs from 16 species residing in seven geographic distinct regions of Alaska. Similar to previous studies, low levels of most inorganic and organic contaminants were found, although concentrations of several inorganic and organic contaminants were higher than those of previous studies. For example, elevated strontium levels were observed in several species, especially black oystercatcher (Haematopus bachmani) sampled in Prince William Sound, Alaska. Additionally, contaminant concentrations varied among species, with significantly higher concentrations of inorganic contaminants found in eggs of pectoral sandpiper (Calidris melanotos), semipalmated sandpiper (Calidris pusilla), black oystercatcher, and bar-tailed godwit (Limosa lapponica). Similarly, significantly higher concentrations of some organic contaminants were found in the eggs of American golden plover (Pluvialis dominica), black-bellied plover (Pluvialis squatarola), pacific golden plover (Pluvialis fulva), bar-tailed godwit, and semipalmated sandpiper. Despite these elevated levels, current concentrations of contaminants in shorebird eggs suggest that breeding environments are relatively free of most contaminants and that contaminant concentrations are below levels (except potentially strontium) that would likely affect the survival of individuals and consequently regulate the species at the population level.

Influence of blood contamination during multimode adhesive application on the microtensile bond strength to dentin.

PubMed

Kucukyilmaz, E; Celik, E U; Akcay, M; Yasa, B

2017-12-01

The present study evaluated the effects of blood contamination performed at different steps of bonding on the microtensile bond strength (μTBS) of multimode adhesives to dentin when using the self-etch approach. Seventy-five molars were randomly assigned to three adhesive groups comprising 25 specimens each: two multimode adhesives [Single Bond Universal (SBU) and All-Bond Universal (ABU)] and a conventional one-step self-etch adhesive [Clearfil S3 Bond Plus (CSBP)]. Each group was subdivided as follows: (1) uncontaminated (control): bonding application/light curing as a positive control; (2) contamination-1 (cont-1): bonding application/light curing/blood contamination/dry as a negative control; (3) contamination-2 (cont-2): bonding application/light curing/blood contamination/rinse/dry; (4) contamination-3 (cont-3): bonding application/blood contamination/dry/bonding re-application/light curing; and (5) contamination-4 (cont-4): bonding application/blood contamination/rinse/dry/bonding re-application/light curing. Dentin specimens were prepared for μTBS testing after the composite resin application. Data were analyzed with two-way ANOVA and post-hoc tests (α = 0.05). μTBS values were similar in cont-3 groups, and ABU/cont-4 and corresponding control groups, but were significantly lower in the other groups than in their control groups (P < 0.05). Cont-1 groups showed the lowest μTBS values (P < 0.05). Neither decontamination method prevented the decrease in μTBS when contamination occurred after light curing. Drying the blood contaminants and reapplying the adhesive may regain the dentin adhesion when contamination occurs before light curing. Alternatively, rinsing and drying contaminants followed by adhesive re-application may be effective depending on adhesive type.

Exposure to emotionally arousing, contamination-relevant pictorial stimuli interferes with response inhibition: Implication for obsessive–compulsive disorder

PubMed Central

Adams, Thomas G.

2016-01-01

Multiple emotional processes are implicated in the pathogenesis of obsessions and compulsions and individuals diagnosed with obsessive-compulsive disorder (OCD) have reliably shown deficits in response inhibition. Little research has tested how emotional processes might interact with cognitive control in the context of OCD. High contamination obsessive-compulsive (OC) and low contamination-OC participants completed an emotional go/no-go task to measure the interfering effects contamination-threat images relative to neutral images on action restraint (errors of commission). Results revealed that high contamination-OC participants committed marginally more commission errors (11.04%) than low contamination-OC participants (10.30%) on neutral no-go trials, but this effect was not significant (p > .05). All participants committed significantly more errors of commission on contamination-threat trails relative to neutral no-go trials, p < .01, but the interfering effects of contamination-threat images was significantly larger (p = .05) for high-contamination-OC participants. Errors of commission almost doubled for high contamination-OC participants on contamination-threat no-go trials (20.78%), compared to a more modest increase for low contamination-OC participants (14.80%). These findings suggest that individuals with elevated symptoms of OCD may have significantly more difficulty inhibiting their actions when processing disorder relevant or emotionally arousing information. This observation has implications for the pathogenesis of obsessions and compulsions. PMID:28090434

Specificity of disgust domains in the prediction of contamination anxiety and avoidance: a multimodal examination.

PubMed

Olatunji, Bunmi O; Ebesutani, Chad; Haidt, Jonathan; Sawchuk, Craig N

2014-07-01

Although core, animal-reminder, and contamination disgust are viewed as distinct "types" of disgust vulnerabilities, the extent to which individual differences in the three disgust domains uniquely predict contamination-related anxiety and avoidance remains unclear. Three studies were conducted to fill this important gap in the literature. Study 1 was conducted to first determine if the three types of disgust could be replicated in a larger and more heterogeneous sample. Confirmatory factor analysis revealed that a bifactor model consisting of a "general disgust" dimension and the three distinct disgust dimensions yielded a better fit than a one-factor model. Structural equation modeling in Study 2 showed that while latent core, animal-reminder, and contamination disgust factors each uniquely predicted a latent "contamination anxiety" factor above and beyond general disgust, only animal-reminder uniquely predicted a latent "non-contamination anxiety" factor above and beyond general disgust. However, Study 3 found that only contamination disgust uniquely predicted behavioral avoidance in a public restroom where contamination concerns are salient. These findings suggest that although the three disgust domains are associated with contamination anxiety and avoidance, individual differences in contamination disgust sensitivity appear to be most uniquely predictive of contamination-related distress. The implications of these findings for the development and maintenance of anxiety-related disorders marked by excessive contamination concerns are discussed. Copyright © 2014. Published by Elsevier Ltd.

Water contamination, land prices, and the statute of repose

Treesearch

John F. Chamblee; Carolyn A. Dehring; Craig A. Depken; Joseph R. Nicholson

2015-01-01

We examine how water contamination risk from an inactive hazardous waste site is capitalized into surrounding vacant land prices. After public knowledge of the first instance of off-site contamination, we find that shallow groundwater contamination potential is negatively capitalized into land prices, as is proximity to a known contaminated well. Public knowledge of...

21 CFR 500.45 - Use of polychlorinated biphenyls (PCB's) in the production, handling, and storage of animal feed.

Code of Federal Regulations, 2010 CFR

2010-04-01

... persistent and ubiquitous contaminant in the environment, causing the contamination of certain foods. In... the contamination of food intended for human consumption (meat, milk, and eggs). Investigations by the... consuming the contaminated silage. Since PCB's are toxic chemicals, the PCB contamination of food as a...

Bacterial community changes in response to oil contamination and perennial crop cultivation.

PubMed

Yan, Lijuan; Penttinen, Petri; Mikkonen, Anu; Lindström, Kristina

2018-05-01

We investigated bacterial community dynamics in response to used motor oil contamination and perennial crop cultivation by 16S rRNA gene amplicon sequencing in a 4-year field study. Actinobacteria, Proteobacteria, Chloroflexi, Acidobacteria, and Gemmatimonadetes were the major bacterial phyla, and Rhodococcus was the most abundant genus. Initially, oil contamination decreased the overall bacterial diversity. Actinobacteria, Betaproteobacteria, and Gammaproteobacteria were sensitive to oil contamination, exhibiting clear succession with time. However, bacterial communities changed over time, regardless of oil contamination and crop cultivation. The abundance difference of most OTUs between oil-contaminated and non-contaminated plots remained the same in later sampling years after the initial abundance difference induced by oil spike. The abundances of three oil-favored actinobacteria (Lysinimonas, Microbacteriaceae, and Marmoricola) and one betaproteobacterium (Aquabacterium) changed in different manner over time in oil-contaminated and non-contaminated soil. We propose that these taxa are potential bio-indicators for monitoring recovery from motor oil contamination in boreal soil. The effect of crop cultivation on bacterial communities became significant only after the crops achieved stable growth, likely associated with plant material decomposition by Bacteroidetes, Armatimonadetes and Fibrobacteres.

Method for removing metal vapor from gas streams

DOEpatents

Ahluwalia, R.K.; Im, K.H.

1996-04-02

A process for cleaning an inert gas contaminated with a metallic vapor, such as cadmium, involves withdrawing gas containing the metallic contaminant from a gas atmosphere of high purity argon; passing the gas containing the metallic contaminant to a mass transfer unit having a plurality of hot gas channels separated by a plurality of coolant gas channels; cooling the contaminated gas as it flows upward through the mass transfer unit to cause contaminated gas vapor to condense on the gas channel walls; regenerating the gas channels of the mass transfer unit; and, returning the cleaned gas to the gas atmosphere of high purity argon. The condensing of the contaminant-containing vapor occurs while suppressing contaminant particulate formation, and is promoted by providing a sufficient amount of surface area in the mass transfer unit to cause the vapor to condense and relieve supersaturation buildup such that contaminant particulates are not formed. Condensation of the contaminant is prevented on supply and return lines in which the contaminant containing gas is withdrawn and returned from and to the electrorefiner and mass transfer unit by heating and insulating the supply and return lines. 13 figs.

Inexact Socio-Dynamic Modeling of Groundwater Contamination Management

NASA Astrophysics Data System (ADS)

Vesselinov, V. V.; Zhang, X.

2015-12-01

Groundwater contamination may alter the behaviors of the public such as adaptation to such a contamination event. On the other hand, social behaviors may affect groundwater contamination and associated risk levels such as through changing ingestion amount of groundwater due to the contamination. Decisions should consider not only the contamination itself, but also social attitudes on such contamination events. Such decisions are inherently associated with uncertainty, such as subjective judgement from decision makers and their implicit knowledge on selection of whether to supply water or reduce the amount of supplied water under the scenario of the contamination. A socio-dynamic model based on the theories of information-gap and fuzzy sets is being developed to address the social behaviors facing the groundwater contamination and applied to a synthetic problem designed based on typical groundwater remediation sites where the effects of social behaviors on decisions are investigated and analyzed. Different uncertainties including deep uncertainty and vague/ambiguous uncertainty are effectively and integrally addressed. The results can provide scientifically-defensible decision supports for groundwater management in face of the contamination.

Cross-ecosystem impacts of stream pollution reduce resource and contaminant flux to riparian food webs

USGS Publications Warehouse

Kraus, Johanna M.; Schmidt, Travis S.; Walters, David; Wanty, Richard B.; Zuellig, Robert E.; Wolf, Ruth E.

2014-01-01

The effects of aquatic contaminants are propagated across ecosystem boundaries by aquatic insects that export resources and contaminants to terrestrial food webs; however, the mechanisms driving these effects are poorly understood. We examined how emergence, contaminant concentration, and total contaminant flux by adult aquatic insects changed over a gradient of bioavailable metals in streams and how these changes affected riparian web-building spiders. Insect emergence decreased 97% over the metal gradient, whereas metal concentrations in adult insects changed relatively little. As a result, total metal exported by insects (flux) was lowest at the most contaminated streams, declining 96% among sites. Spiders were affected by the decrease in prey biomass, but not by metal exposure or metal flux to land in aquatic prey. Aquatic insects are increasingly thought to increase exposure of terrestrial consumers to aquatic contaminants, but stream metals reduce contaminant flux to riparian consumers by strongly impacting the resource linkage. Our results demonstrate the importance of understanding the contaminant-specific effects of aquatic pollutants on adult insect emergence and contaminant accumulation in adults to predict impacts on terrestrial food webs.

Method for removing metal vapor from gas streams

DOEpatents

Ahluwalia, R. K.; Im, K. H.

1996-01-01

A process for cleaning an inert gas contaminated with a metallic vapor, such as cadmium, involves withdrawing gas containing the metallic contaminant from a gas atmosphere of high purity argon; passing the gas containing the metallic contaminant to a mass transfer unit having a plurality of hot gas channels separated by a plurality of coolant gas channels; cooling the contaminated gas as it flows upward through the mass transfer unit to cause contaminated gas vapor to condense on the gas channel walls; regenerating the gas channels of the mass transfer unit; and, returning the cleaned gas to the gas atmosphere of high purity argon. The condensing of the contaminant-containing vapor occurs while suppressing contaminant particulate formation, and is promoted by providing a sufficient amount of surface area in the mass transfer unit to cause the vapor to condense and relieve supersaturation buildup such that contaminant particulates are not formed. Condensation of the contaminant is prevented on supply and return lines in which the contaminant containing gas is withdrawn and returned from and to the electrorefiner and mass transfer unit by heating and insulating the supply and return lines.

Beyond the bed: effects of metal contamination on recruitment to bedded sediments and overlying substrata.

PubMed

Hill, Nicole A; Simpson, Stuart L; Johnston, Emma L

2013-02-01

Metal-contaminated sediments pose a recognised threat to sediment-dwelling fauna. Re-mobilisation of contaminated sediments however, may impact more broadly on benthic ecosystems, including on diverse assemblages living on hard substrata patches immediately above sediments. We used manipulative field experiments to simultaneously test for the effects of metal contamination on recruitment to marine sediments and overlying hard substrata. Recruitment to sediments was strongly and negatively affected by metal contamination. However, while assemblage-level effects on hard-substratum fauna and flora were observed, most functional groups were unaffected or slightly enhanced by exposure to contaminated sediments. Diversity of hard-substratum fauna was also enhanced by metal contamination at one site. Metal-contaminated sediments appear to pose less of a hazard to hard-substratum than sediment-dwelling assemblages, perhaps due to a lower direct contaminant exposure or to indirect effects mediated by contaminant impacts on sediment fauna. Our results indicate that current sediment quality guidelines are protective of hard-substrata organisms. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

Study on contaminants on flight and other critical surfaces

NASA Technical Reports Server (NTRS)

Workman, Gary L.; Hughes, Charles; Arendale, William F.

1994-01-01

The control of surface contamination in the manufacture of space hardware can become a critical step in the production process. Bonded surfaces have been shown to be affected markedly by contamination. It is important to insure surface cleanliness by preventing contamination prior to bonding. In this vein techniques are needed in which the contamination which may affect bonding are easily found and removed. Likewise, if materials which are detrimental to bonding are not easily removed, then they should not be used in the manufacturing process. This study will address the development of techniques to locate and quantify contamination levels of particular contaminants. With other data becoming available from MSFC and its contractors, this study will also quantify how certain contaminants affect bondlines and how easily they are removed in manufacturing.

Microbiologic contamination during dental radiographic film processing.

PubMed

Stanczyk, D A; Paunovich, E D; Broome, J C; Fatone, M A

1993-07-01

This study investigated microbiologic contamination of an automatic dental radiograph processor and daylight loader during a week of simulated clinical use. Pure cultures of Candida albicans, Streptococcus pneumoniae, Staphylococcus aureus, or Klebsiella pneumoniae were used to contaminate 320 vinyl intraoral radiograph packets. Each end of the films was deliberately contaminated during opening. These films and 24 uncontaminated control films were processed. Daylight loader ports, inlet and outlet rollers, fixer and developer samples, and 12 processed films were cultured daily. To simulate a weekend, the processor sites were cultured during 72 hours of inactivity after the contaminated runs. The results showed that contamination of the processor and daylight loader occurred and remained even after 48 hours of inactivity. Films remained contaminated after processing. In addition, cross-contamination of films occurred in the processor.

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.

Microbiological evaluation of a newly designed dental air-turbine handpiece for anti-cross contaminations.

PubMed

Ohsuka, S; Ohta, M; Masuda, K; Kaneda, T; Ueda, M

1994-01-01

The effectiveness of a newly developed anti-cross contamination device for a dental air-turbine handpiece was tested. The handpiece with or without the anti-cross contamination device was contaminated with two bacterial strains, Staphylococcus aureus and Streptococcus mutans, as well as two bacteriophage strains, T2 and MS2. After contamination with these microorganisms, the handpieces were disinfected with glutaraldehyde or replaced with newly autoclaved ones. Residual microorganisms inside the handpiece or an air/water supply hose line were collected and counted after overnight cultivation. The anti-cross contamination device effectively reduced the contamination level of an air-turbine handpiece to that of the negative control. No microbial contamination in the air/water supply hose line was detected with this device.

Contaminated landslide runout deposits in rivers - Method for estimating long-term ecological risks.

PubMed

Göransson, G; Norrman, J; Larson, M

2018-06-14

The potential catastrophic event of a landslide bringing contaminants to surface waters has been highlighted in public media, but there are still few scientific studies analyzing the risk of landslides with contaminated soil. The aim of this study is to present a method to estimate the risk of potential long-term ecological effects on water bodies due to contaminated soil released into a river through a landslide. The study constitutes further development of previous work focusing on the instantaneous (short-term) release of contaminants and associated effects. Risk is here defined as the probability of surface water failing to comply with environmental quality standards (EQS). The transport model formulation is kept simple enough to allow for a probabilistic analysis as a first assessment of the impact on the river water quality from a landslide runout deposit containing contaminated soil. The model is applied at a contaminated site located adjacent to the Göta Älv River that discharges into the Gothenburg estuary, in southwest Sweden. The results from the case study show that a contaminated runout deposit will likely cause contamination levels above EQSs in the near area for a long time and that it will take several years for the deposit to erode, with the greatest erosion at the beginning when water velocities are their highest above the deposit. A contaminated landslide runout deposit will thus act as a source of contamination to the downstream water system until all the contaminated deposit has been eroded away and the contaminants have been transported from the deposit to the river, and further to the river mouth - diluted but not necessarily negligible. Therefore, it is important to prevent landslides of contaminated soil or waste, and if such events were to occur, to remove the contaminated runout deposit as soon as possible. Copyright © 2018. Published by Elsevier B.V.

Linking field-based metabolomics and chemical analyses to prioritize contaminants of emerging concern in the Great Lakes basin.

PubMed

Davis, John M; Ekman, Drew R; Teng, Quincy; Ankley, Gerald T; Berninger, Jason P; Cavallin, Jenna E; Jensen, Kathleen M; Kahl, Michael D; Schroeder, Anthony L; Villeneuve, Daniel L; Jorgenson, Zachary G; Lee, Kathy E; Collette, Timothy W

2016-10-01

The ability to focus on the most biologically relevant contaminants affecting aquatic ecosystems can be challenging because toxicity-assessment programs have not kept pace with the growing number of contaminants requiring testing. Because it has proven effective at assessing the biological impacts of potentially toxic contaminants, profiling of endogenous metabolites (metabolomics) may help screen out contaminants with a lower likelihood of eliciting biological impacts, thereby prioritizing the most biologically important contaminants. The authors present results from a study that utilized cage-deployed fathead minnows (Pimephales promelas) at 18 sites across the Great Lakes basin. They measured water temperature and contaminant concentrations in water samples (132 contaminants targeted, 86 detected) and used 1 H-nuclear magnetic resonance spectroscopy to measure endogenous metabolites in polar extracts of livers. They used partial least-squares regression to compare relative abundances of endogenous metabolites with contaminant concentrations and temperature. The results indicated that profiles of endogenous polar metabolites covaried with at most 49 contaminants. The authors identified up to 52% of detected contaminants as not significantly covarying with changes in endogenous metabolites, suggesting they likely were not eliciting measurable impacts at these sites. This represents a first step in screening for the biological relevance of detected contaminants by shortening lists of contaminants potentially affecting these sites. Such information may allow risk assessors to prioritize contaminants and focus toxicity testing on the most biologically relevant contaminants. Environ Toxicol Chem 2016;35:2493-2502. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US Government work and, as such, is in the public domain in the United States of America. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US Government work and, as such, is in the public domain in the United States of America.

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.

Nutrients versus emerging contaminants-Or a dynamic match between subsidy and stress effects on stream biofilms.

PubMed

Aristi, I; Casellas, M; Elosegi, A; Insa, S; Petrovic, M; Sabater, S; Acuña, V

2016-05-01

Freshwater ecosystems are threatened by multiple anthropogenic stressors, which might be differentiated into two types: those that reduce biological activity at all concentrations (toxic contaminants), and those that subsidize biological activity at low concentrations and reduce it at high concentrations (assimilable contaminants). When occurring in mixtures, these contaminants can have either antagonistic, neutral or synergistic effects; but little is known on their joint effects. We assessed the interaction effects of a mixture of assimilable and toxic contaminants on stream biofilms in a manipulative experiment using artificial streams, and following a factorial design with three nutrient levels (low, medium or high) and either presence or absence of a mixture of emerging contaminants (ciprofloxacin, erythromycin, diclofenac, methylparaben, and sulfamethoxazole). We measured biofilm biomass, basal fluorescence, gross primary production and community respiration. Our initial hypotheses were that biofilm biomass and activity would: increase with medium nutrient concentrations (subsidy effect), but decrease with high nutrient concentrations (stress effect) (i); decrease with emerging contaminants, with the minimum decrease at medium nutrient concentrations (antagonistic interaction between nutrients subsidy and stress by emerging contaminants) and the maximum decrease at high nutrient concentrations (synergistic interaction between nutrients and emerging contaminants stress) (ii). All the measured variables responded linearly to the available nutrients, with no toxic effect at high nutrient concentrations. Emerging contaminants only caused weak toxic effects in some of the measured variables, and only after 3-4 weeks of exposure. Therefore, only antagonistic interactions were observed between nutrients and emerging contaminants, as medium and high nutrient concentrations partly compensated the harmful effects of emerging contaminants during the first weeks of the experiment. Our results show that contaminants with a subsidy effect can alleviate the effects of toxic contaminants, and that long-term experiments are required to detect stress effects of emerging contaminants at environmentally relevant concentrations. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

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.

Influences of climate on aflatoxin producing fungi and aflatoxin contamination.

PubMed

Cotty, Peter J; Jaime-Garcia, Ramon

2007-10-20

Aflatoxins are potent mycotoxins that cause developmental and immune system suppression, cancer, and death. As a result of regulations intended to reduce human exposure, crop contamination with aflatoxins causes significant economic loss for producers, marketers, and processors of diverse susceptible crops. Aflatoxin contamination occurs when specific fungi in the genus Aspergillus infect crops. Many industries frequently affected by aflatoxin contamination know from experience and anecdote that fluctuations in climate impact the extent of contamination. Climate influences contamination, in part, by direct effects on the causative fungi. As climate shifts, so do the complex communities of aflatoxin-producing fungi. This includes changes in the quantity of aflatoxin-producers in the environment and alterations to fungal community structure. Fluctuations in climate also influence predisposition of hosts to contamination by altering crop development and by affecting insects that create wounds on which aflatoxin-producers proliferate. Aflatoxin contamination is prevalent both in warm humid climates and in irrigated hot deserts. In temperate regions, contamination may be severe during drought. The contamination process is frequently broken down into two phases with the first phase occurring on the developing crop and the second phase affecting the crop after maturation. Rain and temperature influence the phases differently with dry, hot conditions favoring the first and warm, wet conditions favoring the second. Contamination varies with climate both temporally and spatially. Geostatistics and multiple regression analyses have shed light on influences of weather on contamination. Geostatistical analyses have been used to identify recurrent contamination patterns and to match these with environmental variables. In the process environmental conditions with the greatest impact on contamination are identified. Likewise, multiple regression analyses allow ranking of environmental variables based on relative influence on contamination. Understanding the impact of climate may allow development of improved management procedures, better allocation of monitoring efforts, and adjustment of agronomic practices in anticipation of global climate change.

Ultraviolet absorption of common spacecraft contaminants. [to control effects of contaminants on optical systems

NASA Technical Reports Server (NTRS)

Colony, J. A.

1979-01-01

Organic contamination of ultraviolet optical systems is discussed. Degradation of signal by reflection, scattering, interference, and absorption is shown. The first three processes depend on the physical state of the contaminant while absorption depends on its chemical structure. The latter phenomenon is isolated from the others by dissolving contaminants in cyclohexane and determining absorption spectra from 2100A to 3600A. A variety of materials representing the types of contaminants responsible for most spaceflight hardware problems is scanned and the spectra is presented. The effect of thickness is demonstrated for the most common contaminant, di(2 ethyl hexyl)phthalate, by scanning successive dilutions.

An evaluation of the infection control potential of a UV clinical podiatry unit.

PubMed

Humphreys, Paul N; Davies, Chris S; Rout, Simon

2014-02-28

Infection control is a key issue in podiatry as it is in all forms of clinical practice. Airborne contamination may be particularly important in podiatry due to the generation of particulates during treatment. Consequently, technologies that prevent contamination in podiatry settings may have a useful role. The aims of this investigation were twofold, firstly to determine the ability of a UV cabinet to protect instruments from airborne contamination and secondly to determine its ability to remove microbes from contaminated surfaces and instruments. A UV instrument cabinet was installed in a University podiatry suite. Impact samplers and standard microbiological techniques were used to determine the nature and extent of microbial airborne contamination. Sterile filters were used to determine the ability of the UV cabinet to protect exposed surfaces. Artificially contaminated instruments were used to determine the ability of the cabinet to remove microbial contamination. Airborne bacterial contamination was dominated by Gram positive cocci including Staphylococcus aureus. Airborne fungal levels were much lower than those observed for bacteria. The UV cabinet significantly reduced (p < 0.05) the observed levels of airborne contamination. When challenged with contaminated instruments the cabinet was able to reduce microbial levels by between 60% to 100% with more complex instruments e.g. clippers, remaining contaminated. Bacterial airborne contamination is a potential infection risk in podiatry settings due to the presence of S. aureus. The use of a UV instrument cabinet can reduce the risk of contamination by airborne microbes. The UV cabinet tested was unable to decontaminate instruments and as such could pose an infection risk if misused.

An evaluation of the infection control potential of a UV clinical podiatry unit

PubMed Central

2014-01-01

Background Infection control is a key issue in podiatry as it is in all forms of clinical practice. Airborne contamination may be particularly important in podiatry due to the generation of particulates during treatment. Consequently, technologies that prevent contamination in podiatry settings may have a useful role. The aims of this investigation were twofold, firstly to determine the ability of a UV cabinet to protect instruments from airborne contamination and secondly to determine its ability to remove microbes from contaminated surfaces and instruments. Method A UV instrument cabinet was installed in a University podiatry suite. Impact samplers and standard microbiological techniques were used to determine the nature and extent of microbial airborne contamination. Sterile filters were used to determine the ability of the UV cabinet to protect exposed surfaces. Artificially contaminated instruments were used to determine the ability of the cabinet to remove microbial contamination. Results Airborne bacterial contamination was dominated by Gram positive cocci including Staphylococcus aureus. Airborne fungal levels were much lower than those observed for bacteria. The UV cabinet significantly reduced (p < 0.05) the observed levels of airborne contamination. When challenged with contaminated instruments the cabinet was able to reduce microbial levels by between 60% to 100% with more complex instruments e.g. clippers, remaining contaminated. Conclusions Bacterial airborne contamination is a potential infection risk in podiatry settings due to the presence of S. aureus. The use of a UV instrument cabinet can reduce the risk of contamination by airborne microbes. The UV cabinet tested was unable to decontaminate instruments and as such could pose an infection risk if misused. PMID:24576315

Tracking cross-contamination transfer dynamics at a mock retail deli market using GloGerm.

PubMed

Maitland, Jessica; Boyer, Renee; Gallagher, Dan; Duncan, Susan; Bauer, Nate; Kause, Janell; Eifert, Joseph

2013-02-01

Ready-to-eat (RTE) deli meats are considered a food at high risk for causing foodborne illness. Deli meats are listed as the highest risk RTE food vehicle for Listeria monocytogenes. Cross-contamination in the retail deli market may contribute to spread of pathogens to deli meats. Understanding potential cross-contamination pathways is essential for reducing the risk of contaminating various products. The objective of this study was to track cross-contamination pathways through a mock retail deli market using an abiotic surrogate, GloGerm, to visually represent how pathogens may spread through the deli environment via direct contact with food surfaces. Six contamination origination sites (slicer blade, meat chub, floor drain, preparation table, employee's glove, and employee's hands) were evaluated separately. Each site was inoculated with 20 ml of GloGerm, and a series of standard deli operations were completed (approximately 10 min of work). Photographs were then taken under UV illumination to visualize spread of GloGerm throughout the deli. A sensory panel evaluated the levels of contamination on the resulting contaminated surfaces. Five of the six contamination origination sites were associated with transfer of GloGerm to the deli case door handle, slicer blade, meat chub, preparation table, and the employee's gloves. Additional locations became contaminated (i.e., deli case shelf, prep table sink, and glove box), but this contamination was not consistent across all trials. Contamination did not spread from the floor drain to any food contact surfaces. The findings of this study reinforce the need for consistent equipment cleaning and food safety practices among deli workers to minimize cross-contamination.

Methods for removing contaminants from algal oil

DOEpatents

Lupton, Francis Stephen

2016-09-27

Methods for removing contaminants from algal oil are provided. In an embodiment, a method comprises the steps of combining a sulfuric acid-aqueous solution that has a pH of about 1 or less with a contaminant-containing algal oil at treatment conditions effective to form an effluent. The effluent comprises a treated algal oil phase and contaminants in an acidic aqueous phase. The contaminants comprise metals, phosphorus, or combinations thereof. The acidic aqueous phase is removed from the effluent to form a contaminant-depleted algal oil.

Tissue floaters and contaminants in the histology laboratory.

PubMed

Platt, Eric; Sommer, Paul; McDonald, Linda; Bennett, Ana; Hunt, Jennifer

2009-06-01

Anatomic pathology diagnosis is often based on morphologic features. In recent years, an appropriate increased attention to patient safety has led to an emphasis on improving maintenance of patient identity. Decreasing or eliminating cross-contamination from one specimen to another is an example of a patient identity issue for which process improvement can be initiated. To quantify the presence of cross-contamination from histology water baths and the slide stainers. We assessed for the presence of contaminants in water baths at cutting stations and in linear stainer stain baths. We assessed the potential for tissue discohesion and carryover in tissue samples and we assessed the potential for carryover onto blank slides sent through the stainer. In the 13 water baths examined (totalling 195 L of water), only one fragment of tissue was identified. The stain baths, however, contained abundant tissue contaminants, ranging in size from 2 to 3 cells to hundreds of cells. The first sets of xylenes and alcohols were the most heavily contaminated. Cross-contamination to blank slides occurred at a rate of 8%, with the highest frequency in the late afternoon. Cross-contamination can present a significant challenge in the histology laboratory. Although the histotechnologists' water baths are not heavily contaminated, the stainer baths do contain contaminating tissue fragments. Cross-contamination does occur onto blank slides in the experimental setting.

Assessing the bioavailability and risk from metal-contaminated ...

EPA Pesticide Factsheets

Exposure to contaminated soil and dust is an important pathway in human health risk assessment. Physical and chemical characteristics, as well as biological factors, determine the bioaccessibility/bioavailability of soil and dust contaminants. Within a single sample, contamination may arise from multiple sources of toxic elements that may exist as different forms (species) which impact bioavailability. In turn, the bioaccessibility/bioavailability of soil and dust contaminants has a direct impact on human health risk assessment and risk management practices. Novel research efforts focusing on development and application of in vitro and in vivo methods to measure the bioaccessibility/bioavailability of metal contaminated soils have advanced in the past few years. The objective of this workshop was to focus on recent developments in assessing the bioaccessibility/bioavailability of arsenic contaminated soils, metal contamination in urban residences in Canada and potential children’s exposures to toxic elements in house dust, a community-based study known as the West Oakland Residential Lead Assessment , studies of the bioavailability of soil cadmium, chromium, nickel and mercury and human exposures to contaminated Brownfield soils. These presentations covered issues related to human health and bioavailability along with the most recent studies on community participation in assessing metal contamination, studies of exposures to residential contamination, and

Salivary contamination during bonding procedures with a one-bottle adhesive system.

PubMed

Fritz, U B; Finger, W J; Stean, H

1998-09-01

The effect of salivary contamination of enamel and dentin on bonding efficacy of an experimental one-bottle resin adhesive was investigated. The adhesive was a light-curing urethane dimethacrylate/hydroxyethyl methacrylate/4-methacryloxyethyl trimellitate anhydride mixture dissolved in acetone. Evaluation parameters were shear bond strength and marginal gap width in a dental cavity. Apart from a control group without contamination (group 1), etched enamel and dentin were (2) contaminated with saliva and air dried; (3) contaminated, rinsed, and blot dried; (4) coated with adhesive, contaminated, rinsed, and blot dried; (5) coated with adhesive, light cured, contaminated, rinsed, and air dried; or (6) treated as in group 5, with additional adhesive application after air drying. There was no negative effect in groups 3 and 4, compared with control. Air drying after salivary contamination (group 2) resulted in low shear bond strengths and wide marginal gaps. Contamination of the cured adhesive layer (groups 5 and 6) had no adverse effect on enamel shear bond strengths, but resulted in 50% reduced dentin shear bond strengths and wide marginal gaps. The one-bottle adhesive system is relatively insensitive to salivary contamination, provided that the contamination occurs prior to light curing of the adhesive and is carefully rinsed and blot dried. Salivary contact after adhesive curing must be avoided.

Mental contamination: The effects of religiosity.

PubMed

Bilekli, Ilgun; Inozu, Mujgan

2018-03-01

Mental contamination, which occurs in the absence of contact with a contaminant, has a moral element. Previous studies evoked feelings of mental contamination via listening to a scenario, which described a non-consensual kiss. Since mental contamination has a moral element, we tested the effects of the level of religiosity on feelings of mental contamination and related variables in an experimental design. Female undergraduates of high religiosity (n = 48) and low religiosity (n = 44) were randomly assigned to listen to one of two audio recordings involving a consensual or non-consensual kiss from a man described as moral. Mental contamination feelings were evoked successfully in both groups. Effects of scenario condition and religiosity level were seen in mental contamination and related negative feelings. Participants who imagined a non-consensual kiss reported greatest feelings of mental contamination, and internal and external negative feelings. More importantly, high religiosity resulted in greater feelings of mental contamination, internal negative feelings, as well as urges to wash and actual washing behaviors. The current study was conducted on non-clinical Muslim females. This limits the generalization of the findings to the wider population. Mental contamination and related feelings can be seen in different forms at different levels of religiosity. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

Emerging Contaminants and Federal Facility Contaminants of Concern

EPA Pesticide Factsheets

This page links to fact sheets summarizing contaminants of concern and emerging contaminants that present unique issues and challenges to the environmental community in general and to FFRRO in particular.

Aspergillus DNA contamination in blood collection tubes.

PubMed

Harrison, Elizabeth; Stalhberger, Thomas; Whelan, Ruth; Sugrue, Michele; Wingard, John R; Alexander, Barbara D; Follett, Sarah A; Bowyer, Paul; Denning, David W

2010-08-01

Fungal polymerase chain reaction (PCR)-based diagnostic methods are at risk for contamination. Sample collection containers were investigated for fungal DNA contamination using real-time PCR assays. Up to 18% of blood collection tubes were contaminated with fungal DNA, probably Aspergillus fumigatus. Lower proportions of contamination in other vessels were observed. Copyright 2010 Elsevier Inc. All rights reserved.

Feasibility study of contaminant detection for food with ULF-NMR/MRI system using HTS-SQUID

NASA Astrophysics Data System (ADS)

Hatsukade, Yoshimi; Tsunaki, Shingo; Yamamoto, Masaaki; Abe, Takayuki; Hatta, Junichi; Tanaka, Saburo

2013-11-01

We have developed an ultra-low frequency (ULF) nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) system utilizing an HTS-SQUID for an application of contaminant detection in food and drink. In the system, a permanent magnet of 1.1 T was used to pre-polarize protons in a water sample. We measured NMR signals from water samples with or without various contaminants, such as stainless steel (SUS304), aluminum, and glass balls using the system. In the case that the contaminant was the SUS304 ball, the NMR signal intensity was reduced compared to that from the sample without the contaminant due to the remnant field of the contaminant. One-dimensional (1D) MRIs of the samples were also acquired to detect non-magnetic contaminants. In the 1D MRIs, changes of the MRI spectra were detected, corresponding to positions of the contaminants. These results show that the feasibility of the system to detect various contaminants in foods.

Organochlorine contaminants and Tree Swallows along the Fox River and Green Bay, Wisconsin, USA

USGS Publications Warehouse

Custer, Christine M.; Custer, T.W.; Allen, P. David; Stromborg, K.L.; Melancon, M.J.; Adams, N.J.; Slotow, R.H.

1999-01-01

Green Bay, Wisconsin is contaminated with polychlorinated biphenyls (PCBs) however, whether these contaminants affect reproduction in insectivorous birds is unknown. Tree Swallows, Tachycineta bicolor, are secondary cavity nesters that will nest in boxes and tolerate handling. Because Tree Swallows are aquatic insectivores, residues in their tissues are primarily indicative of contaminants in sediments. We studied swallows at two contaminated and two reference colonies in 1993, 1994, and 1995 in the Green Bay area. Swallows at the two contaminated sites had significantly higher PCB levels in eggs when compared to two reference sites. Eggs from clutches that contained dead embryos had higher PCB concentrations than eggs from clutches where all eggs hatched; there were no contaminant effects overall on reproduction, however. Twelve-day-old nestlings at the two contaminated sites accumulated significantly more PCBs than did nestlings at the reference sites demonstrating that PCB contamination came from the local area. The PCB congener profile in 12-day-old nestlings mirrored the congener profile in their food.

Evaluating soil contamination

USGS Publications Warehouse

Beyer, W.N.

1990-01-01

This compilation was designed to help U.S. Fish and Wildlife Service contaminant specialists evaluate the degree of contamination of a soil, based on chemical analyses. Included are regulatory criteria, opinions, brief descriptions of scientific articles, and miscellaneous information that might be useful in making risk assessments. The intent was to make hard-to-obtain material readily available to contaminant specialists, but not to critique the material or develop new criteria. The compilation is to be used with its index, which includes about 200 contaminants. There are several entries for a few of the most thoroughly studied contaminants, but for most of them the information available is meager. Entries include soil contaminant criteria from other countries, contaminant guidelines for applying sewage sludge to soil, guidelines for evaluating sediments, background soil concentrations for various elements, citations to scientific articles that may help estimate the potential movement of soil contaminants into wildlife food chains, and a few odds and ends. Articles on earthworms were emphasized because they are a natural bridge between soil and many species of wildlife.

Disgust and Obsessive Beliefs in Contamination-related OCD

PubMed Central

Cisler, Josh M.; Brady, Robert E.; Olatunji, Bunmi O.; Lohr, Jeffrey M.

2010-01-01

A large body of evidence suggests that disgust is an important affective process underlying contamination fear. An independent line of research demonstrates that obsessive beliefs, particularly overestimations of threat, are also an important cognitive process underlying contamination fear. The present study attempts to integrate these two lines of research by testing whether obsessive beliefs potentiate the influence of disgust propensity on contamination fear. The interaction between disgust propensity and obsessive beliefs was tested in two large non-clinical samples (N = 252 in Study 1; N = 308 in Study 2) using two different self-report measures of contamination fear. Regression analyses supported the hypotheses in both samples. The interaction remained significant when controlling for negative affect. The results are hypothesized to suggest that contamination fear results, at least partly, from obsessive beliefs about the contamination-based appraisals that accompany heightened disgust responding. These results complement previous affective-driven explanations of the role of disgust in contamination fear by suggesting cognitive factors that similarly potentiate disgust’s role in contamination fear. PMID:20877585

Nanoparticle interactions with co-existing contaminants: joint toxicity, bioaccumulation and risk.

PubMed

Deng, Rui; Lin, Daohui; Zhu, Lizhong; Majumdar, Sanghamitra; White, Jason C; Gardea-Torresdey, Jorge L; Xing, Baoshan

2017-06-01

With their growing production and application, engineered nanoparticles (NPs) are increasingly discharged into the environment. The released NPs can potentially interact with pre-existing contaminants, leading to biological effects (bioaccumulation and/or toxicity) that are poorly understood. Most studies on NPs focus on single analyte exposure; the existing literature on joint toxicity of NPs and co-existing contaminants is rather limited but beginning to develop rapidly. This is the first review paper evaluating the current state of knowledge regarding the joint effects of NPs and co-contaminants. Here, we review: (1) methods for investigating and evaluating joint effects of NPs and co-contaminants; (2) simultaneous toxicities from NPs co-exposed with organic contaminants, metal/metalloid ions, dissolved organic matter (DOM), inorganic ligands and additional NPs; and (3) the influence of NPs co-exposure on the bioaccumulation of organic contaminants and heavy metal ions, as well as the influence of contaminants on NPs bioaccumulation. In addition, future research needs are discussed so as to better understand risk associated with NPs-contaminant co-exposure.

Urine culture contamination: a College of American Pathologists Q-Probes study of 127 laboratories.

PubMed

Bekeris, Leonas G; Jones, Bruce Allen; Walsh, Molly K; Wagar, Elizabeth A

2008-06-01

While urine culture contamination may not be completely avoidable, some laboratories have lower contamination rates than others. A College of American Pathologists (CAP) 1998 Q-Probes study showed that many interventions commonly assumed to reduce contamination were not demonstrably effective. This article revisits the issue. To examine the frequency of urine culture contamination, review current laboratory practices in the collection of urine culture specimens, and determine practice characteristics that may be associated with the contamination rate. Laboratories participating in a CAP Q-Probes study were required to prospectively collect data on 120 consecutive urine culture specimens and provide information on the patient's demographics (age and sex), the location where the specimen was collected, how the specimen was handled, the number of isolates in quantities greater than or equal to 10,000 colony-forming units (CFU)/mL, and whether the laboratory considered the specimen to be contaminated. Specific inclusion and exclusion criteria were provided to the participants. Each laboratory completed a supplemental questionnaire that probed for specific laboratory urine culture collection practices. One hundred twenty-seven laboratories participated in the study. Results from a total of 14,739 urine specimens were received. For the purpose of this study, a urine specimen was determined to be contaminated if the culture yielded more than 2 isolates in quantities greater than or equal to 10,000 CFU/mL. Using these criteria the median institution had a contamination rate of 15.0%. Laboratories in the 10th percentile (low performance) had an average contamination rate of 41.7%, while laboratories in the 90th percentile had an average rate of 0.8%. The collection site had no influence on the contamination rate, but postcollection processing, especially refrigeration of the specimen, had a substantial effect. Providing instruction to patients produced a statistically significant lowering of contamination rates for specimens from male patients (P = .006) but not for female patients, except when written instructions were provided in the emergency room, in which case specimen contamination rates for both male and female patients dropped (P = .01). The median contamination rates remain at a level comparable to the results seen in a previous Q-Probes study, and some laboratories have very high contamination rates. Specimen refrigeration is associated with lower overall urine culture specimen contamination rate. Providing patient instruction is also associated with lower contamination rates under specific circumstances.

Estimated association between dwelling soil contamination and internal radiation contamination levels after the 2011 Fukushima Daiichi nuclear accident in Japan.

PubMed

Tsubokura, Masaharu; Nomura, Shuhei; Sakaihara, Kikugoro; Kato, Shigeaki; Leppold, Claire; Furutani, Tomoyuki; Morita, Tomohiro; Oikawa, Tomoyoshi; Kanazawa, Yukio

2016-06-29

Measurement of soil contamination levels has been considered a feasible method for dose estimation of internal radiation exposure following the Chernobyl disaster by means of aggregate transfer factors; however, it is still unclear whether the estimation of internal contamination based on soil contamination levels is universally valid or incident specific. To address this issue, we evaluated relationships between in vivo and soil cesium-137 (Cs-137) contamination using data on internal contamination levels among Minamisoma (10-40 km north from the Fukushima Daiichi nuclear power plant), Fukushima residents 2-3 years following the disaster, and constructed three models for statistical analysis based on continuous and categorical (equal intervals and quantiles) soil contamination levels. A total of 7987 people with a mean age of 55.4 years underwent screening of in vivo Cs-137 whole-body counting. A statistically significant association was noted between internal and continuous Cs-137 soil contamination levels (model 1, p value <0.001), although the association was slight (relative risk (RR): 1.03 per 10 kBq/m(2) increase in soil contamination). Analysis of categorical soil contamination levels showed statistical (but not clinical) significance only in relatively higher soil contamination levels (model 2: Cs-137 levels above 100 kBq/m(2) compared to those <25 kBq/m(2), RR=1.75, p value <0.01; model 3: levels above 63 kBq/m(2) compared to those <11 kBq/m(2), RR=1.45, p value <0.05). Low levels of internal and soil contamination were not associated, and only loose/small associations were observed in areas with slightly higher levels of soil contamination in Fukushima, representing a clear difference from the strong associations found in post-disaster Chernobyl. These results indicate that soil contamination levels generally do not contribute to the internal contamination of residents in Fukushima; thus, individual measurements are essential for the precise evaluation of chronic internal radiation contamination. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Why conventional detection methods fail in identifying the existence of contamination events.

PubMed

Liu, Shuming; Li, Ruonan; Smith, Kate; Che, Han

2016-04-15

Early warning systems are widely used to safeguard water security, but their effectiveness has raised many questions. To understand why conventional detection methods fail to identify contamination events, this study evaluates the performance of three contamination detection methods using data from a real contamination accident and two artificial datasets constructed using a widely applied contamination data construction approach. Results show that the Pearson correlation Euclidean distance (PE) based detection method performs better for real contamination incidents, while the Euclidean distance method (MED) and linear prediction filter (LPF) method are more suitable for detecting sudden spike-like variation. This analysis revealed why the conventional MED and LPF methods failed to identify existence of contamination events. The analysis also revealed that the widely used contamination data construction approach is misleading. Copyright © 2016 Elsevier Ltd. All rights reserved.

Contamination control research activities for space optics in JAXA RANDD

NASA Astrophysics Data System (ADS)

Kimoto, Y.

2017-11-01

Contamination control research activities for space optics projects in JAXA R&D are described. More accurate contamination control techniques are requested because of intensified recent science mission requirements. One approach to control the contamination effects is analysis by software. JAXA has been developing a contamination analytical tool "J-SPICE" (Japanese Spacecraft Induced Contamination analysis software) as well as experiment facilities to improve the J-SPICE. A reflection model in J-SPICE has been experimentally verified and outgassing model data has been acquired by a facility. JAXA has developed a facility which could determine the influence of the contamination at a specific wavelength by combining a vacuum chamber with an I-R spectrometer and performed an experiment to inspect the effect of baking. Space material exposure experiment results reveal the actual thickness of the contamination layer in ISS orbit.

WF/PC internal molecular contamination during system thermal-vacuum test

NASA Technical Reports Server (NTRS)

Taylor, Daniel M.; Barengoltz, J.; Jenkins, T.; Leschly, K.; Triolo, J.

1988-01-01

During the recent system thermal vacuum test of the Wide-Field/Planetary Camera (WF/PC), instrumentation was added to the WF/PC to characterize the internal molecular contamination and verify the instrument throughput down to 1470 angstroms. Analysis of data elements revealed two contaminants affecting the far-ultraviolet (FUV) performance of the WF/PC. The one contaminant (heavy volatile) is correlated with the electronic and housing temperature, and the contamination is significantly reduced when the electronics are operated below plus 8 degrees to plus 10 degrees C. The other contaminant (light volatile) is controlled by the heat pipe temperature, and the contamination is significantly reduced when the Thermal Electric Cooler (TEC) hot-junction temperature is below minus 40 degrees to minus 50 degrees C. The utility of contamination sensors located behind instruments during system tests was demonstrated.

The influence of microplastics and halogenated contaminants in feed on toxicokinetics and gene expression in European seabass (Dicentrarchus labrax).

PubMed

Granby, Kit; Rainieri, Sandra; Rasmussen, Rie Romme; Kotterman, Michiel J J; Sloth, Jens Jørgen; Cederberg, Tommy Licht; Barranco, Alex; Marques, António; Larsen, Bodil Katrine

2018-07-01

When microplastics pollute fish habitats, it may be ingested by fish, thereby contaminating fish with sorbed contaminants. The present study investigates how combinations of halogenated contaminants and microplastics associated with feed are able to alter toxicokinetics in European seabass and affect the fish. Microplastic particles (2%) were added to the feed either with sorbed contaminants or as a mixture of clean microplastics and chemical contaminants, and compared to feed containing contaminants without microplastics. For the contaminated microplastic diet, the accumulation of polychlorinated biphenyls (PCBs) and brominated flame retardants (BFRs) in fish was significantly higher, increasing up to 40 days of accumulation and then reversing to values comparable to the other diets at the end of accumulation. The significant gene expression results of liver (cyp1a, il1β, gstα) after 40 days of exposure indicate that microplastics might indeed exacerbate the toxic effects (liver metabolism, immune system, oxidative stress) of some chemical contaminants sorbed to microplastics. Seabass quickly metabolised BDE99 to BDE47 by debromination, probably mediated by deiodinase enzymes, and unlike other contaminants, this metabolism was unaffected by the presence of microplastics. For the other PCBs and BFRs, the elimination coefficients were significantly lower in fish fed the diet with contaminants sorbed to microplastic compared to the other diets. The results indicate that microplastics affects liver detoxification and lipid distribution, both of which affect the concentration of contaminants. Copyright © 2018 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.

Effects of feeding grains naturally contaminated with Fusarium mycotoxins with and without a polymeric glucomannan mycotoxin adsorbent on reproductive performance and serum chemistry of pregnant gilts.

PubMed

Díaz-Llano, G; Smith, T K

2006-09-01

Contamination of animal feedstuffs with Fusarium mycotoxins can cause reduced feed intake and hyperaminoacidemia resulting from reduced hepatic protein synthesis. The current study investigated the effects of feeding grains naturally contaminated with Fusarium mycotoxins on reproductive performance, serum chemistry, ADFI, and ADG of gilts, and tested the ability of a polymeric glucomannan mycotoxin adsorbent (GMA) to reduce or eliminate the effects of the contaminated feeds. Thirty-six Yorkshire gilts were fed 3 diets (n = 12 gilts/diet) from 91 +/- 3 d of gestation until farrowing. Diets included 1) control, 2) contaminated grains, and 3) contaminated grains + 0.2% GMA. Diets contaminated with Fusarium mycotoxins did not affect ADFI (P = 0.24), but ADG (P = 0.029) and G:F (P = 0.047) were reduced. Serum concentrations of beta-hydroxybutyrate, haptoglobin, protein, albumin, globulin, urea, glucose, cholesterol, Ca, Na, Mg, P, K, and Cl, and hepatic enzyme activities were not affected by diet. The frequency of stillborn piglets was greater (P = 0.03) for gilts fed contaminated grains compared with that of gilts fed contaminated grains + GMA. The feeding of contaminated grains + GMA also increased (P = 0.026) the percentage of pigs born alive compared with gilts fed the contaminated diets. In conclusion, feeding gilts diets that are naturally contaminated with Fusarium mycotoxins can increase the incidence of stillborn piglets and this effect can be reduced by dietary supplementation with GMA.

Immune response of greenback flounder Rhombosolea tapirina after exposure to contaminated marine sediment and diet.

PubMed

Mondon, J A; Duda, S; Nowak, B F

2000-01-01

Non-specific immune response of greenback flounder, Rhombosolea tapirina, exposed to contaminated marine sediments was examined. Reference sediments from Port Sorell and contaminated sediments from Deceitful Cove, Tasmania, Australia were investigated. Hatchery-reared flounder were exposed to reference sediment, contaminated sediment or contaminated sediment and diet for 6 weeks. Phagocytic capacity and lysozyme response in flounder were examined on cessation of exposure trial. Significant differences were found in phagocytic capacity and lysozyme response between treatments. Exposure to contaminated sediment, irrespective of diet or benthic disturbance elicited inhibition of phagocytic efficiency in flounder. Disturbance of contaminated sediment stimulated lysozyme activity. The immune response in flounder indicates potential immunotoxicity of sediment from Deceitful Cove.

The relationship between patient functional status and environmental contamination by Clostridium difficile: a pilot study

PubMed Central

Blakney, Rebekah; Gudnadottir, Unnur; Warrack, Simone; O'Horo, John C.; Anderson, Michael; Sethi, Ajay; Schmitz, Michelle; Wang, Jennifer; Duster, Megan; Ide, Emma; Safdar, Nasia

2016-01-01

Introduction Limited data exist on patient factors related to environmental contamination with Clostridium difficile. Methods We evaluated the association between the functional status of patients with C. difficile infection (CDI) and environmental contamination with C. difficile. Results Contamination of patient rooms was frequent and higher functional status was associated with contaminated surfaces remote from the bed. All but one environmental isolates matched the corresponding patient's stool isolate for the seven patients tested. Conclusion Functional status is a factor that influences environmental contamination with C. difficile. Future studies should evaluate strategies to reduce contamination in CDI patient rooms, taking into account the patient's functional status. PMID:25869819

40 CFR 312.31 - The degree of obviousness of the presence or likely presence of contamination at the property...

Code of Federal Regulations, 2010 CFR

2010-07-01

... presence or likely presence of contamination at the property, and the ability to detect the contamination... obviousness of the presence or likely presence of contamination at the property, and the ability to detect the contamination by appropriate investigation. (a) Persons to whom this part is applicable per § 312.1(b) and...

Spacecraft contamination programs within the Air Force Systems Command Laboratories

NASA Technical Reports Server (NTRS)

Murad, Edmond

1990-01-01

Spacecraft contamination programs exist in five independent AFSC organizations: Geophysics Laboratory (GL), Arnold Engineering and Development Center (AEDC), Rome Air Development Center (RADC/OSCE), Wright Research and Development Center (MLBT), Armament Laboratory (ATL/SAI), and Space Systems Division (SSD/OL-AW). In addition, a sizable program exists at Aerospace Corp. These programs are complementary, each effort addressing a specific area of expertise: GL's effort is aimed at addressing the effects of on-orbit contamination; AEDC's effort is aimed at ground simulation and measurement of optical contamination; RADC's effort addresses the accumulation, measurement, and removal of contamination on large optics; MLBT's effort is aimed at understanding the effect of contamination on materials; ATL's effort is aimed at understanding the effect of plume contamination on systems; SSD's effort is confined to the integration of some contamination experiments sponsored by SSD/CLT; and Aerospace Corp.'s effort is aimed at supporting the needs of the using System Program Offices (SPO) in specific areas, such as contamination during ground handling, ascent phase, laboratory measurements aimed at understanding on-orbit contamination, and mass loss and mass gain in on-orbit operations. These programs are described in some detail, with emphasis on GL's program.

Geology and ground water in Door County, Wisconsin, with emphasis on contamination potential in the Silurian dolomite

USGS Publications Warehouse

Sherrill, Marvin G.

1977-01-01

Door County, a recreational and fruit-growing area bordering Lake Michigan in northeastern Wisconsin, has had a long history of ground-water contamination from surface and near-surface sources. Contamination is most severe in late summer when fruit-canning operations and the influx of tourists create additional wastes. Silurian dolomite is the upper bedrock unit in the county and yields generally adequate supplies of very hard water with locally objectionable concentrations of iron and nitrate. Thin soil cover and well-fractured dolomitic bedrock give easy entry to ground-water contaminants throughout large parts of Door County. Many contaminants enter the dolomite by surface or near-surface seepage. There is little attenuation of contamination concentrations in the well-jointed dolomite, and contaminants may travel long distances underground in a relatively short time. The major source of ground-water contamination is bacteria, from individual waste-disposal systems, agricultural, industrial, and municipal wastes. Areas of the county underlain by contaminated zones include only a small percentage of the total ground-water system and are separated by large volumes of ground water free of contamination. (Woodard-USGS)

Contaminated Sites in Europe: Review of the Current Situation Based on Data Collected through a European Network

PubMed Central

Van Liedekerke, Marc; Yigini, Yusuf; Montanarella, Luca

2013-01-01

Under the European Union (EU) Thematic Strategy for Soil Protection, the European Commission has identified soil contamination as a priority for the collection of policy-relevant soil data at European scale. In order to support EU soil management policies, soil-related indicators need to be developed which requires appropriate data collection and establishment of harmonized datasets for the EU Member States. In 2011-12, the European Soil Data Centre of the European Commission conducted a project to collect data on contaminated sites from national institutions in Europe using the European Environment Information and Observation Network for soil (EIONET-SOIL). This paper presents the results obtained from analysing the soil contaminated sites data submitted by participating countries. According to the received data, the number of estimated potential contaminated sites is more than 2.5 million and the identified contaminated sites around 342 thousand. Municipal and industrial wastes contribute most to soil contamination (38%), followed by the industrial/commercial sector (34%). Mineral oil and heavy metals are the main contaminants contributing around 60% to soil contamination. In terms of budget, the management of contaminated sites is estimated to cost around 6 billion Euros (€) annually. PMID:23843802

Bioavailability of sediment-associated mercury to Hexagenia mayflies in a contaminated floodplain river

USGS Publications Warehouse

Naimo, T.J.; Wiener, J.G.; Cope, W.G.; Bloom, N.S.

2000-01-01

We examined the bioavailability of mercury in sediments from the contaminated Sudbury River (Massachusetts, U.S.A.). Mayfly nymphs (Hexagenia) were exposed in four 21-day bioaccumulation tests to contaminated and reference sediments (treatments) from reservoirs, flowing reaches, palustrine wetlands, and a riverine lake. Mean total mercury (Sigma Hg) ranged from 880 to 22 059 ng.g dry weight(-1) in contaminated sediments and from 90 to 272 ng.g(-1) in reference sediments. Mean final concentrations of methyl mercury (MeHg) in test water were greatest (8-47 ng Hg.L-1) in treatments with contaminated wetland sediments, which had mean Sigma Hg ranging from 1200 to 2562 ng.g(-1). In mayflies, final mean concentrations of MeHg were highest in treatments with contaminated wetland sediments (122-183 ng Hg.g(-1)), intermediate in treatments with contaminated sediments from reservoirs, flowing reaches, and a riverine lake (75-127 ng Hg.g(-1)), and lowest in treatments with reference sediments (32-41 ng Hg.g(-1)). We conclude that the potential entry of MeHg into the benthic food chain was greater in contaminated palustrine wetlands than in the contaminated reservoirs, which had the most contaminated sediments.

Comparison of two possible routes of pathogen contamination of spinach leaves in a hydroponic cultivation system.

PubMed

Koseki, Shigenobu; Mizuno, Yasuko; Yamamoto, Kazutaka

2011-09-01

The route of pathogen contamination (from roots versus from leaves) of spinach leaves was investigated with a hydroponic cultivation system. Three major bacterial pathogens, Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes, were inoculated into the hydroponic solution, in which the spinach was grown to give concentrations of 10⁶ and 10³ CFU/ml. In parallel, the pathogens were inoculated onto the growing leaf surface by pipetting, to give concentrations of 10⁶ and 10³ CFU per leaf. Although contamination was observed at a high rate through the root system by the higher inoculum (10⁶ CFU) for all the pathogens tested, the contamination was rare when the lower inoculum (10³ CFU) was applied. In contrast, contamination through the leaf occurred at a very low rate, even when the inoculum level was high. For all the pathogens tested in the present study, the probability of contamination was promoted through the roots and with higher inoculum levels. The probability of contamination was analyzed with logistic regression. The logistic regression model showed that the odds ratio of contamination from the roots versus from the leaves was 6.93, which suggested that the risk of contamination from the roots was 6.93 times higher than the risk of contamination from the leaves. In addition, the risk of contamination by L. monocytogenes was about 0.3 times that of Salmonella enterica subsp. enterica serovars Typhimurium and Enteritidis and E. coli O157:H7. The results of the present study indicate that the principal route of pathogen contamination of growing spinach leaves in a hydroponic system is from the plant's roots, rather than from leaf contamination itself.

Groundwater pumping effects on contaminant loading management in agricultural regions.

PubMed

Park, Dong Kyu; Bae, Gwang-Ok; Kim, Seong-Kyun; Lee, Kang-Kun

2014-06-15

Groundwater pumping changes the behavior of subsurface water, including the location of the water table and characteristics of the flow system, and eventually affects the fate of contaminants, such as nitrate from agricultural fertilizers. The objectives of this study were to demonstrate the importance of considering the existing pumping conditions for contaminant loading management and to develop a management model to obtain a contaminant loading design more appropriate and practical for agricultural regions where groundwater pumping is common. Results from this study found that optimal designs for contaminant loading could be determined differently when the existing pumping conditions were considered. This study also showed that prediction of contamination and contaminant loading management without considering pumping activities might be unrealistic. Motivated by these results, a management model optimizing the permissible on-ground contaminant loading mass together with pumping rates was developed and applied to field investigation and monitoring data from Icheon, Korea. The analytical solution for 1-D unsaturated solute transport was integrated with the 3-D saturated solute transport model in order to approximate the fate of contaminants loaded periodically from on-ground sources. This model was further expanded to manage agricultural contaminant loading in regions where groundwater extraction tends to be concentrated in a specific period of time, such as during the rice-growing season, using a method that approximates contaminant leaching to a fluctuating water table. The results illustrated that the simultaneous management of groundwater quantity and quality was effective and appropriate to the agricultural contaminant loading management and the model developed in this study, which can consider time-variant pumping, could be used to accurately estimate and to reasonably manage contaminant loading in agricultural areas. Copyright © 2014 Elsevier Ltd. All rights reserved.

Near and far field contamination modeling in a large scale enclosure: Fire Dynamics Simulator comparisons with measured observations.

PubMed

Ryder, Noah L; Schemel, Christopher F; Jankiewicz, Sean P

2006-03-17

The occurrence of a fire, no matter how small, often exposes objects to significant levels of contamination from the products of combustion. The production and dispersal of these contaminants has been an issue of relevance in the field of fire science for many years, though little work has been done to examine the contamination levels accumulated within an enclosure some time after an incident. This phenomenon is of great importance when considering the consequences associated with even low level contamination of sensitive materials, such as food, pharmaceuticals, clothing, electrical equipment, etc. Not only does such exposure present a localized hazard, but also the shipment of contaminated goods places distant recipients at risk. It is the intent of this paper to use a well-founded computational fluid dynamic (CFD) program, the Fire Dynamics Simulator (FDS), a large eddy simulation (LES) code developed by National Institute of Standards and Technology (NIST), to model smoke dispersion in order to assess the subject of air contamination and post fire surface contamination in a warehouse facility. Measured results are then compared with the results from the FDS model. Two components are examined: the production rate of contaminates and the trajectory of contaminates caused by the forced ventilation conditions. Each plays an important role in determining the extent to which the products of combustion are dispersed and the levels to which products are exposed to the contaminants throughout the enclosure. The model results indicate a good first-order approximation to the measured surface contamination levels. The proper application of the FDS model can provide a cost and time efficient means of evaluating contamination levels within a defined volume.

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.

Impact of inorganic contaminants on microalgae productivity and bioremediation potential.

PubMed

Torres, Eric M; Hess, Derek; McNeil, Brian T; Guy, Tessa; Quinn, Jason C

2017-05-01

As underdeveloped nations continue to industrialize and world population continues to increase, the need for energy, natural resources, and goods will lead to ever increasing inorganic contaminants, such as heavy metals, in various waste streams that can have damaging effects on plant life, wildlife, and human health. This work is focused on the evaluation of the potential of Nannochloropsis salina to be integrated with contaminated water sources for the concurrent production of a biofuel feedstock while providing an environmental service through bioremediation. Individual contaminants (As, Cd, Cr, Co, Cu, Pb, Ni, Hg, Se, and Zn) at various concentrations ranging from a low concentration (1X) to higher concentrations (10X, and 40X) found in contaminated systems (mine tailings, wastewater treatment plants, produced water) were introduced into growth media. Biological growth experimentation was performed in triplicate at the various contaminant concentrations and at 3 different light intensities. Results show that baseline concentrations of each contaminant slightly decreased biomass growth to between 89% and 99% of the control with the exception of Ni which dramatically reduced growth. Increased contaminant concentrations resulted in progressively lower growth rates for all contaminants tested. Lipid analysis shows most baseline contaminant concentrations slightly decrease or have minimal effects on lipid content at all light levels. Trace contaminant analysis on the biomass showed Cd, Co, Cu, Pb, and Zn were sorbed by the microalgae with minimal contaminants remaining in the growth media illustrating the effectiveness of microalgae to bioremediate these contaminants when levels are sufficiently low to not detrimentally impact productivity. The microalgae biomass was less efficient at sorption of As, Cr, Ni, and Se. Copyright © 2017 Elsevier Inc. All rights reserved.

Understanding the Behaviour of Contamination Spread in Nagarjuna Sagar Reservoir Using Temporal Landsat Data

NASA Astrophysics Data System (ADS)

Tarun Teja, K.; Rajan, K. S.

2016-06-01

LANDSAT images are used to identify organic contaminants in water bodies, but, there is no enough evidence in present literature that LANDSAT is also good in identifying a mixture of organic and mineral contaminants such as agricultural waste. The focus of this paper is to evaluate the effectiveness of LANDSAT imagery to identify organic and mineral contamination (OMC) and to identify spread extent variations of pollution over the season/year in the Nagarjuna Sagar (NS) reservoir using only satellite images. A new band combination is proposed in order to detect OMC, because existing formulae based on band ratio proved to be inadequate in detecting the contamination in NS. Difference in reflectance values of Red and Green channel of an image helps clearly distinguish clear water from OMC water. This procedure was applied over LANDSAT data of the calendar years 2008, 2014 and 2015 to understand the contamination spread pattern through the reservoir. Results show that contamination is following a similar pattern over these calendar years. In January contamination starts at inlets and by May contamination spreads to almost 90% of the reservoir when the total area of water spread is also reduced by half. Contamination spread is low during the monsoonal period of June to September due to heavy inflow and heavy outflow of waters from NS reservoir. Post monsoon NS is contaminated again because of heavy inflow of runoffs from neighboring land use and limited water outflow. This contamination spread pattern matches the agricultural seasons and fertilizer application pattern in this region, indicating that agricultural use of fertilizers could be one of the primary causes of contamination for this waterbody.

In situ removal of contamination from soil

DOEpatents

Lindgren, Eric R.; Brady, Patrick V.

1997-01-01

A process of remediation of cationic heavy metal contamination from soil utilizes gas phase manipulation to inhibit biodegradation of a chelating agent that is used in an electrokinesis process to remove the contamination, and further gas phase manipulation to stimulate biodegradation of the chelating agent after the contamination has been removed. The process ensures that the chelating agent is not attacked by bioorganisms in the soil prior to removal of the contamination, and that the chelating agent does not remain as a new contaminant after the process is completed.

In situ removal of contamination from soil

DOEpatents

Lindgren, E.R.; Brady, P.V.

1997-10-14

A process of remediation of cationic heavy metal contamination from soil utilizes gas phase manipulation to inhibit biodegradation of a chelating agent that is used in an electrokinesis process to remove the contamination. The process also uses further gas phase manipulation to stimulate biodegradation of the chelating agent after the contamination has been removed. The process ensures that the chelating agent is not attacked by bioorganisms in the soil prior to removal of the contamination, and that the chelating agent does not remain as a new contaminant after the process is completed. 5 figs.

Compositions and methods for removing arsenic in water

DOEpatents

Gadgil, Ashok Jagannth [El Cerrito, CA

2011-02-22

Compositions and methods and for contaminants from water are provided. The compositions comprise ferric hydroxide and ferric oxyhydride coated substrates for use in removing the contaminant from the water. Contacting water bearing the contaminant with the substrates can substantially reduce contaminant levels therein. Methods of oxidizing the contaminants in water to facilitate their removal by the ferric hydroxide and ferric oxyhydride coated substrates are also provided. The contaminants include, but are not limited to, arsenic, selenium, uranium, lead, cadmium, nickel, copper, zinc, chromium and vanadium, their oxides and soluble salts thereof.

Shuttle/spacelab contamination environment and effects handbook

NASA Technical Reports Server (NTRS)

Bareiss, L. E.; Payton, R. M.; Papazian, H. A.

1986-01-01

This handbook is intended to assist users of the Spacelab/Space Transportation System by providing contamination environments and effects information that may be of value in planning, designing, manufacturing, and operating a space flight experiment. A summary of available molecular and particulate contamination data on the Space Transportation System and its facilities is presented. Contamination models, contamination effects, and protection methods information are also presented. In addition to contamination, the effects of the space environments at STS altitudes on spacecraft materials are included. Extensive references, bibliographies, and contacts are provided.

Influence of hang time and location on bacterial contamination of intravenous bags in a veterinary emergency and critical care setting.

PubMed

Guillaumin, Julien; Olp, Nichole M; Magnusson, Karissa D; Butler, Amy L; Daniels, Joshua B

2017-09-01

To assess the rate of bacterial contamination of fluid and ports in intravenous bags in a veterinary emergency room (ER) and intensive care unit (ICU). Experimental model. Ninety intravenous fluid bags of lactated balanced-electrolytes solution (1 L) hung in a university hospital. Bags were hung in 2 different locations in the ER (sink and bins) and one location in the ICU (sink) for 11 days. Bags were punctured 3 times daily with a sterile needle to simulate clinical use. Injection ports were swabbed and 50 mL of fluid were collected in duplicates on days 0, 2, 4, 7, and 10. Aerobic bacterial cultures were performed on the fluid and injection port. Contamination was defined as bacterial growth of a similar phenotype across 2 consecutive times. Increase in the fluid contamination rate from day 0 was tested using an exact binomial test. Port contamination rate between locations was tested using Fisher's exact test. Combined bacterial growth on injection ports reached a mean (95% confidence interval) of 8.1 (0.005-16.2) cfu/port on day 10. The combined port contamination was 3.3%, 11.1%, 17.8%, and 31.1% on days 0, 2, 4, and 7, respectively. Port contamination was similar between ER and ICU. However, port contamination was higher in the sink versus the bins area (38.3% vs 16.7%, P = 0.032). No fluid bag was contaminated at days 0 and 2. The contamination rate of fluid bag was 1.1% and 4.4% on days 4 and 7, respectively. All bags with contaminated fluid were in the ER (6.7%, 95% exact binomial confidence interval 1.9-16.2%). Injection port contamination reached 31.1% on day 7. Contamination was more likely when the bags were hung next to a sink. In our model of bag puncture, fluid contamination occurred between days 2 and 4. © Veterinary Emergency and Critical Care Society 2017.

Capabilities of the Materials Contamination Team at Marshall Space Flight Center

NASA Technical Reports Server (NTRS)

Burns, Howard; Albyn, Keith; Edwards, David; Boothe, Richard; Finchum, Charles; Finckenor, Miria

2003-01-01

The Materials Contamination Team at the Marshall Space Flight Center (MSFC) has been recognized for its contributions supporting the National Aeronautics and Space Administration (NASA) spacecraft development programs. These programs include the Reusable Solid Rocket Motor (RSRM), Chandra X-Ray Observatory, and the International Space Station (ISS). The Environmental Effects Group, with the Materials Contamination Team and the Space Environmental Effects Team has been an integral part of NASA's success by the testing, evaluation, and qualification of materials, hardware, and processes. This paper focuses on the capabilities of the Materials Contamination Team. The Materials Contamination Team's realm of responsibility includes establishing contamination control during all phases of hardware development, including design, manufacturing, assembly, test, transportation, launch site processing, on-orbit exposure, return, and refurbishment. The team continues its mission of reducing the risk of equipment failure due to molecular or particulate contamination. Contamination is a concern in the Space Shuttle with sensitive bond-lines and reactive fluid (liquid oxygen) compatibility as well as for spacecraft with sensitive optics, such as Hubble Space Telescope and Chandra X-ray Observatory. The Materials Contamination Team has a variety of facilities and instrumentation capable of contaminant detection, identification, and monitoring. The team addresses material applications dealing with environments, including production facilities, clean rooms, and on-orbit exposure. The optically stimulated electron emission (OSEE) system, the Ultraviolet (UV) fluorescence (UVF) surface contamination detection, and the Surface Optics Corporation 400 (SOC 400) portable hand-held Fourier Transform Infrared (FTIR) spectrometer are state-of-the-art tools for in-process molecular contamination detection. The team of engineers and technicians also develop contamination calibration standards and evaluate new surface cleanliness inspection technologies. The team utilizes facilities for on-orbit simulation testing of materials for outgassing and molecular film deposition characteristics in the presence of space environmental effects, such as Atomic Oxygen (AO) and UV radiation exposure. The Materials Contamination Team maintains databases for process materials as well as outgassing and optical compatibility test results for specific environments.

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.

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

Rick Demmer; John Drake; Ryan James, PhD

Over the last 50 years, the study of radiological contamination and decontamination has expanded significantly. This paper addresses the mechanisms of radiological contamination that have been reported and then discusses which methods have recently been used during performance testing of several different decontamination technologies. About twenty years ago the Idaho Nuclear Technology Engineering Center (INTEC) at the INL began a search for decontamination processes which could minimize secondary waste. In order to test the effectiveness of these decontamination technologies, a new simulated contamination, termed SIMCON, was developed. SIMCON was designed to replicate the types of contamination found on stainless steel,more » spent fuel processing equipment. Ten years later, the INL began research into methods for simulating urban contamination resulting from a radiological dispersal device (RDD). This work was sponsored by the Defense Advanced Research Projects Agency (DARPA) and included the initial development an aqueous application of contaminant to substrate. Since 2007, research sponsored by the US Environmental Protection Agency (EPA) has advanced that effort and led to the development of a contamination method that simulates particulate fallout from an Improvised Nuclear Device (IND). The IND method diverges from previous efforts to create tenacious contamination by simulating a reproducible “loose” contamination. Examining these different types of contamination (and subsequent decontamination processes), which have included several different radionuclides and substrates, sheds light on contamination processes that occur throughout the nuclear industry and in the urban environment.« less

[The current situation of occupational protection against skin/mucosa contamination among obstetrician and gynecologist].

PubMed

Zhang, Yujuan; Li, Peng; Wang, Jianmei; Huo, Yan; Yang, Jing

2015-03-01

To investigate the occurrence and protection of skin/mucosa contamination among obstetrician and gynecologist. By random, stratified, and clustered sampling, 219 obstetrician and gynecologist were selected. 210 valid questionnaires were collected, efficiency is 95.89%. 110 obstetrician and gynecologist come from tertiary hospitals, 100 come from secondary hospitals. A self-administered questionnaire on skin/mucosa contamination was employed to gauge the implementation of protection, types and working links of skin/mucosa contamination. Of the respondents, only 14.76% (31/210) and 5.24% (11/210) adhered to proper hand washing and wearing protective glasses within nearly 1 year in practical work. Of the respondents, 73.81% (155/210) had experienced the skin/mucosa contamination during their vocation, 50.95% (107/210) occurred sharps injuries, 45.71% (96/210) occurred damaged skin contamination, and 43.33% (91/210) occurred mucosa contamination. Sharps injuries mainly occurred when abdominal operation (45.71%, 96/120), damaged skin contamination mainly occurred when gynecological examination (21.43%, 45/210), and mucosa contamination mainly occurred when midwifery (37.14%, 78/210). The implementation of protective measures is inadequate and incidence of skin/mucosa contamination is higher among obstetrician and gynecologist. Therefore, occupational protection education should focus on different types and working links of skin/mucosa contamination. At the same time, strict supervision and management system should be established.

Depth Stratification Leads to Distinct Zones of Manganese and Arsenic Contaminated Groundwater.

PubMed

Ying, Samantha C; Schaefer, Michael V; Cock-Esteb, Alicea; Li, Jun; Fendorf, Scott

2017-08-15

Providing access to safe drinking water is a global challenge, for which groundwater is increasingly being used throughout the world. However, geogenic contaminants limit the suitability of groundwater for domestic purposes over large geographic areas across most continents. Geogenic contaminants in groundwater are often evaluated individually, but here we demonstrate the need to evaluate multiple contaminants to ensure that groundwater is safe for human consumption and agricultural usage. We compiled groundwater chemical data from three aquifer regions across the world that have been reported to have widespread As and Mn contamination including the Glacial Aquifer in the U.S., the Ganges-Brahmaputra-Mehta Basin within Bangladesh, and the Mekong Delta in Cambodia, along with newly sampled wells in the Yangtze River Basin of China. The proportion of contaminated wells increase by up to 40% in some cases when both As and Mn contaminants are considered. Wilcoxon rank-sum analysis indicates that Mn contamination consistently occurs at significantly shallower depths than As contaminated wells in all regions. Arsenic concentrations in groundwater are well predicted by redox indicators (Eh and dissolved oxygen) whereas Mn shows no significant relationship with either parameter. These findings illustrate that the number of safe wells may be drastically overestimated in some regions when Mn contamination is not taken into account and that depth may be used as a distinguishing variable in efforts to predict the presence of groundwater contaminants regionally.

Does modifying personal responsibility moderate the mental contamination effect?

PubMed

Kennedy, Tinisha S; Simonds, Laura M

2017-12-01

Mental contamination is the psychological sense of internal dirtiness that arises in the absence of physical contact with a perceived contaminant. Mental contamination can be evoked through imagining perpetrating a moral transgression. This study experimentally evoked mental contamination by asking men to imagine perpetrating a non-consensual kiss. It explored whether reducing sense of personal responsibility for the kiss moderated the mental contamination effect. Male students (N = 60) imagined giving either a consensual or non-consensual kiss. Personal responsibility for the kiss was manipulated in one of two non-consensual kiss conditions by way of the inclusion of social influence information. Feelings of mental contamination were assessed by self-report and through a behavioural index. Mental contamination was successfully induced in the two non-consensual kiss conditions. There was evidence to support the hypothesis that reducing personal responsibility might moderate specific components of mental contamination (shame, dirtiness and urge to cleanse). The effect of responsibility modification was evident in the self-report measures, but not in the behavioural index. The sample comprised male university students which limits generalizability of the findings. The behavioural assessment of mental contamination was limited to a proxy measure. Imagined moral violations are associated with increases in indices of mental contamination. Further research should investigate whether feelings of shame, dirtiness and urge to cleanse are particularly responsive to responsibility modifications. Copyright © 2017 Elsevier Ltd. All rights reserved.

Potential air contamination during CO2 angiography using a hand-held syringe: theoretical considerations and gas chromatography.

PubMed

Cho, David R; Cho, Kyung J; Hawkins, Irvin F

2006-01-01

To assess air contamination in the hand-held syringes currently used for CO2 delivery and to determine whether there is an association between their position and the rate of air contamination. Assessment of air contamination in the syringe (20 ml) included theoretical modeling, mathematical calculation, and gas chromatography (GC). The model was used with Fick's first law to calculate the diffusion of CO2 and the amount of air contamination. For GC studies, the syringes were placed in the upright, horizontal, and inverted positions and gas samples were obtained after 5, 10, 20, 30, and 60 min. All trials with each position for each sampling time were performed five times. The amounts of air contamination with time calculated mathematically were 5-10% less than those of GC. With the diffusivity of air-CO2 at 0.1599 cm2/sec (9.594 cm2/min), air contamination was calculated to be 60% at 60 min. With GC air contamination was 13% at 5 min, 31% at 20 min, 43% at 30 min, and 68% at 60 min. There was no difference in air contamination between the different syringe positions. Air contamination occurs in hand-held syringes filled with CO2 when they are open to the ambient air. The amounts of air contamination over time are similar among syringes placed in the upright, horizontal, and inverted positions.

Automatic Avoidance Tendencies in Individuals with Contamination-Related Obsessive-Compulsive Symptoms

PubMed Central

Najmi, Sadia; Kuckertz, Jennie M.; Amir, Nader

2010-01-01

We used an Approach-Avoidance Task (AAT) to examine response to threatening stimuli in 20 individuals high in contamination-related obsessive-compulsive symptoms (HCs) and 21 individuals low in contamination-related obsessive-compulsive symptoms (LCs). Participants were instructed to respond to contamination-related and neutral pictures by pulling a joystick towards themselves or by pushing it away from themselves. Moving the joystick changed the size of the image to simulate approaching or distancing oneself from the object. Consistent with our hypothesis, the HC group was significantly slower in pulling contamination-related pictures than in pulling neutral pictures, whereas in the LC group there was no difference between speed of pulling contamination-related pictures and neutral pictures. Contrary to our hypothesis, we did not find support for faster pushing away of contamination-related pictures than neutral pictures by the HC group. Moreover, the degree of avoidance of contamination-related stimuli when pulling – but not when pushing – was significantly correlated with self-reported contamination-related obsessive-compulsive symptoms. These results suggest a biased behavioral response for threatening objects in individuals high in contamination fears only when inhibiting the prepotent response to avoid threatening stimuli and not when performing a practiced avoidance response. Thus, our results validate the use of the AAT as a measure of inhibited and uninhibited automatic avoidance reactions to emotional information in individuals with contamination-related obsessive-compulsive symptoms. PMID:20650448

Assessing groundwater quality in Greece based on spatial and temporal analysis.

PubMed

Dokou, Zoi; Kourgialas, Nektarios N; Karatzas, George P

2015-12-01

The recent industrial growth together with the urban expansion and intensive agriculture in Greece has increased groundwater contamination in many regions of the country. In order to design successful remediation strategies and protect public health, it is very important to identify those areas that are most vulnerable to groundwater contamination. In this work, an extensive contamination database from monitoring wells that cover the entire Greek territory during the last decade (2000-2008) was used in order to study the temporal and spatial distribution of groundwater contamination for the most common and serious anionic and cationic trace element pollutants (heavy metals). Spatial and temporal patterns and trends in the occurrence of groundwater contamination were also identified highlighting the regions where the higher groundwater contamination rates have been detected across the country. As a next step, representative contaminated aquifers in Greece, which were identified by the above analysis, were selected in order to analyze the specific contamination problem in more detail. To this end, geostatistical techniques (various types of kriging, co-kriging, and indicator kriging) were employed in order to map the contaminant values and the probability of exceeding critical thresholds (set as the parametric values of the contaminant of interest in each case). The resulting groundwater contamination maps could be used as a useful tool for water policy makers and water managers in order to assist the decision-making process.

Natural Attenuation of Nonvolatile Contaminants in the Capillary Fringe.

PubMed

Kurt, Zohre; Mack, E Erin; Spain, Jim C

2016-09-20

When anoxic polluted groundwater encounters the overlying vadose zone an oxic/anoxic interface is created, often near the capillary fringe. Biodegradation of volatile contaminants in the capillary fringe can prevent vapor migration. In contrast, the biodegradation of nonvolatile contaminants in the vadose zone has received comparatively little attention. Nonvolatile compounds do not cause vapor intrusion, but they still move with the groundwater and are major contaminants. Aniline (AN) and diphenylamine (DPA) are examples of toxic nonvolatile contaminants found often at dye and munitions manufacturing sites. In this study, we tested the hypothesis that bacteria can aerobically biodegrade AN and DPA in the capillary fringe and decrease the contaminant concentrations in the anoxic plume beneath the vadose zone. Laboratory multiport columns that represented the unsaturated zone were used to evaluate degradation of AN or DPA in contaminated water. The biodegradation fluxes of the contaminants were estimated to be 113 ± 26 mg AN·m(-2)·h(-1) and 76 ± 18 mg DPA·m(-2)·h(-1) in the presence of bacteria known to degrade AN and DPA. Oxygen and contaminant profiles along with enumeration of bacterial populations indicated that most of the biodegradation took place within the lower part of the capillary fringe. The results indicate that bacteria capable of contaminant biodegradation in the capillary fringe can create a sink for nonvolatile contaminants.

Evaluation of human health risks posed by carcinogenic and non-carcinogenic multiple contaminants associated with consumption of fish from Taihu Lake, China.

PubMed

Yu, Yingxin; Wang, Xinxin; Yang, Dan; Lei, Bingli; Zhang, Xiaolan; Zhang, Xinyu

2014-07-01

The present study estimated the human daily intake and uptake of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), polycyclic aromatic hydrocarbons (PAHs), and toxic trace elements [mercury (Hg), chromium (Cr), cadmium (Cd), and arsenic (As)] due to consumption of fish from Taihu Lake, China, and the associated potential health risks posed by these contaminants. The health risks posed by the contaminants were assessed using a risk quotient of the fish consumption rate to the maximum allowable fish consumption rate considering the contaminants for carcinogenic and non-carcinogenic effect endpoints. The results showed that fish consumption would not pose non-cancer risks. However, some species would cause a cancer risk. Relative risks of the contaminants were calculated to investigate the contaminant which posed the highest risk to humans. As a result, in view of the contaminants for carcinogenic effects, As was the contaminant which posed the highest risk to humans. However, when non-carcinogenic effects of the contaminants were considered, Hg posed the highest risk. The risk caused by PBDEs was negligible. The results demonstrated that traditional contaminants, such as As, Hg, DDTs (dichlorodiphenyltrichloroethane and its metabolites), and PCBs, require more attention in Taihu Lake than the other target contaminants. Copyright © 2014 Elsevier Ltd. All rights reserved.

[Perceived risks of food contaminants].

PubMed

Koch, Severine; Lohmann, Mark; Epp, Astrid; Böl, Gaby-Fleur

2017-07-01

Food contaminants can pose a serious health threat. In order to carry out adequate risk communication measures, the subjective risk perception of the public must be taken into account. In this context, the breadth of the topic and insufficient terminological delimitations from residues and food additives make an elaborate explanation of the topic to consumers indispensable. A representative population survey used language adequate for lay people and a clear definition of contaminants to measure risk perceptions with regard to food contaminants among the general public. The study aimed to assess public awareness of contaminants and the perceived health risks associated with them. In addition, people's current knowledge and need for additional information, their attitudes towards contaminants, views on stakeholder accountability, as well as compliance with precautionary measures, such as avoiding certain foods to reduce health risks originating from contaminants, were assessed. A representative sample of 1001 respondents was surveyed about food contaminants via computer-assisted telephone interviewing. The majority of respondents rated contaminants as a serious health threat, though few of them spontaneously mentioned examples of undesirable substances in foods that fit the scientific or legal definition of contaminants. Mercury and dioxin were the most well-known contaminants. Only a minority of respondents was familiar with pyrrolizidine alkaloids. The present findings highlight areas that require additional attention and provide implications for risk communication geared to specific target groups.

32 CFR 644.524 - Reporting contaminated land to the General Services Administration.

Code of Federal Regulations, 2010 CFR

2010-07-01

... and Other Contamination from Proposed Excess Land and Improvements § 644.524 Reporting contaminated... concerning: (a) The extent and type of such contamination; (b) Plans for decontamination, if any; and (c) The...

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

Payload/orbiter contamination control requirement study: Spacelab configuration contamination study

NASA Technical Reports Server (NTRS)

Bareiss, L. E.; Hetrick, M. A.; Ress, E. B.; Strange, D. A.

1976-01-01

The assessment of the Spacelab carrier induced contaminant environment was continued, and the ability of Spacelab to meet established contamination control criteria for the space transportation system program was determined. The primary areas considered included: (1) updating, refining, and improving the Spacelab contamination computer model and contamination analysis methodology, (2) establishing the resulting adjusted induced environment predictions for comparison with the applicable criteria, (3) determining the Spacelab design and operational requirements necessary to meet the criteria, (4) conducting mission feasibility analyses of the combined Spacelab/Orbiter contaminant environment for specific proposed mission and payload mixes, and (5) establishing a preliminary Spacelab mission support plan as well as model interface requirements; A summary of those activities conducted to date with respect to the modelling, analysis, and predictions of the induced environment, including any modifications in approach or methodology utilized in the contamination assessment of the Spacelab carrier, was presented.

Cadastral valuation of land contaminated with radionuclides

NASA Astrophysics Data System (ADS)

Ratnikov, A. N.; Sapozhnikov, P. M.; Sanzharova, N. I.; Sviridenko, D. G.; Zhigareva, T. L.; Popova, G. I.; Panov, A. V.; Kozlova, I. Yu.

2016-01-01

The methodology and procedure for cadastral valuation of land in the areas contaminated with radionuclides are presented. The efficiency of rehabilitation measures applied to decrease crop contamination to the levels satisfying sanitary-hygienic norms is discussed. The differentiation of cadastral value of radioactively contaminated agricultural lands for the particular farms and land plots is suggested. An example of cadastral valuation of agricultural land contaminated during the Chernobyl Nuclear Power Plant accident is given. It is shown that the use of sandy and loamy sandy soddy-podzolic soils with the 137Cs contamination of 37-185 and >185 kBq/m2 for crop growing is unfeasible. The growing of grain crops and potatoes on clay loamy soddy-podzolic soils with the 137Cs contamination of 555-740 kBq/m2 is unprofitable. The maximum cadastral value of radioactively contaminated lands is typical of leached chernozems.

Effect of risk information exposure on consumers' responses to foods with insect contamination.

PubMed

Kimura, Atsushi; Magariyama, Yukio; Miyanoshita, Akihiro; Imamura, Taro; Shichiri, Kumiko; Masuda, Tomohiro; Wada, Yuji

2014-02-01

This study explores the impact that scientific information about insect contamination of food has on consumer perceptions. Participants (n = 320, Japanese consumers) were randomly assigned to 1 of 8 information-type conditions: (1) information about insect type, (2) information about contamination processes, (3) information about the safety of contaminated food, (4, 5, 6) combinations of 2 of (1), (2), and (3) above, (7) all information, and (8) no-information, and asked to rate their valuation, behavioral intention, and attitude toward food with insect contamination. Results demonstrated that some combinations of scientific information that include the safety of the contaminated food are effective to reduce consumers' compulsive rejection of insect contamination in food, whereas the single presentation of information about insect type increases consumers' explicit rejection of both the contaminated product and the manufacturer. These findings have implications for the coordination of risk communication strategies. © 2014 Institute of Food Technologists®

Relationships of environmental contaminants to reproductive success in red-breasted mergansers (Mergus serrator) from Lake Michigan

USGS Publications Warehouse

Heinz, G.H.; Haseltine, S.D.; Reichel, W.L.; Hensler, G.L.

1983-01-01

In 1977 and 1978, we studied red-breasted mergansers Mergus serrator nesting on islands in northwestern Lake Michigan to determine whether environmental contaminants were having effects on reproduction. Seventeen contaminants were measured in randomly chosen eggs from 206 nests under study. Using a variety of statistical approaches, we looked for effects of individual contaminants and combinations of contaminants on reproductive measurements such as nest desertion, failure of eggs to hatch, death of newly hatched ducklings, percentage hatching success, number of ducklings leaving the nest and eggshell thickness. We also looked for relationships between the levels of some contaminants in blood samples of 39 incubating females and reproductive success. A small degree of eggshell thinning was attributed to DDE and a few other statistical tests were significant, but no contaminant or combination of contaminants we measured seemed to have a pronounced effect on the aspects of reproduction we followed.

Contamination of the Arctic reflected in microbial metagenomes from the Greenland ice sheet

NASA Astrophysics Data System (ADS)

Hauptmann, Aviaja L.; Sicheritz-Pontén, Thomas; Cameron, Karen A.; Bælum, Jacob; Plichta, Damian R.; Dalgaard, Marlene; Stibal, Marek

2017-07-01

Globally emitted contaminants accumulate in the Arctic and are stored in the frozen environments of the cryosphere. Climate change influences the release of these contaminants through elevated melt rates, resulting in increased contamination locally. Our understanding of how biological processes interact with contamination in the Arctic is limited. Through shotgun metagenomic data and binned genomes from metagenomes we show that microbial communities, sampled from multiple surface ice locations on the Greenland ice sheet, have the potential for resistance to and degradation of contaminants. The microbial potential to degrade anthropogenic contaminants, such as toxic and persistent polychlorinated biphenyls, was found to be spatially variable and not limited to regions close to human activities. Binned genomes showed close resemblance to microorganisms isolated from contaminated habitats. These results indicate that, from a microbiological perspective, the Greenland ice sheet cannot be seen as a pristine environment.

Biofilm formation and ethanol inhibition by bacterial contaminants of biofuel fermentation.

PubMed

Rich, Joseph O; Leathers, Timothy D; Bischoff, Kenneth M; Anderson, Amber M; Nunnally, Melinda S

2015-11-01

Bacterial contaminants can inhibit ethanol production in biofuel fermentations, and even result in stuck fermentations. Contaminants may persist in production facilities by forming recalcitrant biofilms. A two-year longitudinal study was conducted of bacterial contaminants from a Midwestern dry grind corn fuel ethanol facility. Among eight sites sampled in the facility, the combined liquefaction stream and yeast propagation tank were consistently contaminated, leading to contamination of early fermentation tanks. Among 768 contaminants isolated, 92% were identified as Lactobacillus sp., with the most abundant species being Lactobacillus plantarum, Lactobacillus casei, Lactobacillus mucosae, and Lactobacillus fermentum. Seven percent of total isolates showed the ability to form biofilms in pure cultures, and 22% showed the capacity to significantly inhibit ethanol production. However, these traits were not correlated. Ethanol inhibition appeared to be related to acetic acid production by contaminants, particularly by obligately heterofermentative species such as L. fermentum and L. mucosae. Published by Elsevier Ltd.

Contamination assessment for OSSA space station IOC payloads

NASA Technical Reports Server (NTRS)

Chinn, S.; Gordon, T.; Rantanen, R.

1987-01-01

The results are presented from a study for the Space Station Planners Group of the Office of Space Sciences and Applications. The objectives of the study are: (1) the development of contamination protection requirements for protection of Space Station attached payloads, serviced payloads and platforms; and (2) the determination of unknowns or major impacts requiring further assessment. The nature, sources, and quantitative properties of the external contaminants to be encountered on the Station are summarized. The OSSA payload contamination protection requirements provided by the payload program managers are reviewed and the level of contamination awareness among them is discussed. Preparation of revisions to the contamination protection requirements are detailed. The comparative impact of flying the Station at constant atmospheric density rather than constant altitude is assessed. The impact of the transverse boom configuration of the Station on contamination is also assessed. The contamination protection guidelines which OSSA should enforce during their development of payloads are summarized.

Feed contamination with Fusarium mycotoxins induces a corticosterone stress response in broiler chickens.

PubMed

Antonissen, G; De Baere, S; Devreese, M; Van Immerseel, F; Martel, A; Croubels, S

2017-01-01

The aim of the present study was to evaluate the effect of the Fusarium mycotoxins deoxynivalenol (DON) and fumonisins (FBs) on the stress response in broiler chickens, using corticosterone (CORT) in plasma as a biomarker. Chickens were fed either a control diet, a DON contaminated diet, a FBs contaminated diet, or a DON and FBs contaminated diet for 15 d at concentrations close to the European Union maximum guidance levels for DON and FBs in poultry. Mean plasma CORT levels were significantly higher in broiler chickens fed a DON contaminated and a DON and FBs contaminated diet compared to birds fed a control diet. A similar trend was observed for animals fed a FBs contaminated diet. Consequently, feeding broilers a diet contaminated with DON and/or FBs induced a CORT stress response, which may indicate a negative effect on animal welfare. © 2016 Poultry Science Association Inc.

Payload/orbiter contamination control requirement study

NASA Technical Reports Server (NTRS)

Bareiss, L. E.; Ress, E. B.

1975-01-01

The results of a contamination impact analysis upon the spacelab carrier and the spacelab carrier upon some of its potential payloads are presented. These results are based upon contamination computer modeling techniques developed to predict the induced environment for spacelab and to provide the basis for evaluation of the predicted environment against the current on orbit contamination control criteria as specified for payloads. Those spacelab carrier contamination sources evaluated against the stated contamination control criteria were outgassing/offgassing of the major nonmetallic thermal control coating of the spacelab carriers, spacelab core and experiment module and tunnel cabin atmosphere leakage, avionics bay vent, spacelab condensate vent, random particulate sloughing, and the return flux of the molecular content of these sources from the gas-gas interactions with the ambient orbital environment. It is indicated that the spacelab carrier can meet the intent of the contamination control criteria through incorporating known contamination control practices.

Control of contaminants on sensors. Report 1: Interdirectorate working group on earth observation sensors

NASA Technical Reports Server (NTRS)

Hovis, W.; Smith, D.; Mcculloch, A.; Goldberg, I. L.; Ostrow, H.; Seidenberg, B.

1973-01-01

Examples of contamination of sensors from various sources during space missions are presented. Design precautions to provide access to optical surfaces and venting of outgassing products are recommended as methods for coping with contamination. The effects of the sensor materials on sensor contamination are analyzed. Actions to be taken during transportation, storage, and testing of sensors to avoid contamination are discussed.

Method of producing hydrogen, and rendering a contaminated biomass inert

DOEpatents

Bingham, Dennis N [Idaho Falls, ID; Klingler, Kerry M [Idaho Falls, ID; Wilding, Bruce M [Idaho Falls, ID

2010-02-23

A method for rendering a contaminated biomass inert includes providing a first composition, providing a second composition, reacting the first and second compositions together to form an alkaline hydroxide, providing a contaminated biomass feedstock and reacting the alkaline hydroxide with the contaminated biomass feedstock to render the contaminated biomass feedstock inert and further producing hydrogen gas, and a byproduct that includes the first composition.

Quality of Source Water from Public-Supply Wells in the United States, 1993-2007

USGS Publications Warehouse

Toccalino, Patricia L.; Norman, Julia E.; Hitt, Kerie J.

2010-01-01

More than one-third of the Nation's population receives their drinking water from public water systems that use groundwater as their source. The U.S. Geological Survey (USGS) sampled untreated source water from 932 public-supply wells, hereafter referred to as public wells, as part of multiple groundwater assessments conducted across the Nation during 1993-2007. The objectives of this study were to evaluate (1) contaminant occurrence in source water from public wells and the potential significance of contaminant concentrations to human health, (2) national and regional distributions of groundwater quality, and (3) the occurrence and characteristics of contaminant mixtures. Treated finished water was not sampled. The 932 public wells are widely distributed nationally and include wells in selected parts of 41 states and withdraw water from parts of 30 regionally extensive aquifers used for public water supply. These wells are distributed among 629 unique public water systems-less than 1 percent of all groundwater-supplied public water systems in the United States-but the wells were randomly selected within the sampled hydrogeologic settings to represent typical aquifer conditions. Samples from the 629 systems represent source water used by one-quarter of the U.S. population served by groundwater-supplied public water systems, or about 9 percent of the entire U.S. population in 2008. One groundwater sample was collected prior to treatment or blending from each of the 932 public wells and analyzed for as many as six water-quality properties and 215 contaminants. Consistent with the terminology used in the Safe Drinking Water Act (SDWA), all constituents analyzed in water samples in this study are referred to as 'contaminants'. More contaminant groups were assessed in this study than in any previous national study of public wells and included major ions, nutrients, radionuclides, trace elements, pesticide compounds, volatile organic compounds (VOCs), and fecal-indicator microorganisms. Contaminant mixtures were assessed in subsets of samples in which most contaminants were analyzed. Contaminant concentrations were compared to human-health benchmarks-regulatory U.S. Environmental Protection Agency (USEPA) Maximum Contaminant Levels (MCLs) for contaminants regulated in drinking water under the SDWA or non-regulatory USGS Health-Based Screening Levels (HBSLs) for unregulated contaminants, when available. Nearly three-quarters of the contaminants assessed in this study are unregulated in drinking water, and the USEPA uses USGS data on the occurrence of unregulated contaminants in water resources to fulfill part of the SDWA requirements for determining whether specific contaminants should be regulated in drinking water in the future. More than one in five (22 percent) source-water samples from public wells contained one or more naturally occurring or man-made contaminants at concentrations greater than human-health benchmarks, and 80 percent of samples contained one or more contaminants at concentrations greater than one-tenth of benchmarks. Most individual contaminant detections, however, were less than one-tenth of human-health benchmarks. Public wells yielding water with contaminant concentrations greater than benchmarks, as well as those with concentrations greater than one-tenth of benchmarks, were distributed throughout the United States and included wells that withdraw water from all principal aquifer rock types included in this study. Ten contaminants individually were detected at concentrations greater than human-health benchmarks in at least 1 percent of source-water samples and collectively accounted for most concentrations greater than benchmarks. Seven of these 10 contaminants occur naturally, including three radionuclides (radon, radium, and gross alpha-particle radioactivity) and four trace elements (arsenic, manganese, strontium, and boron); three of these 10 contaminants (dieldrin, nitrate, and perchl

Surface contamination on LDEF exposed materials

NASA Technical Reports Server (NTRS)

Hemminger, Carol S.

1992-01-01

X-ray photoelectron spectroscopy (XPS) has been used to study the surface composition and chemistry of Long Duration Exposure Facility (LDEF) exposed materials including silvered Teflon (Ag/FEP), Kapton, S13GLO paint, quartz crystal monitors (QCM's), carbon fiber/organic matrix composites, and carbon fiber/Al Alloy composites. In each set of samples, silicones were the major contributors to the molecular film accumulated on the LDEF exposed surfaces. All surfaces analyzed have been contaminated with Si, O, and C; most have low levels (less than 1 atom percent) of N, S, and F. Occasionally observed contaminants included Cl, Na, K, P, and various metals. Orange/brown discoloration observed near vent slots in some Ag/FEP blankets were higher in carbon, sulfur, and nitrogen relative to other contamination types. The source of contamination has not been identified, but amine/amide functionalities were detected. It is probable that this same source of contamination account for the low levels of sulfur and nitrogen observed on most LDEF exposed surfaces. XPS, which probes 50 to 100 A in depth, detected the major sample components underneath the contaminant film in every analysis. This probably indicates that the contaminant overlayer is patchy, with significant areas covered by less that 100 A of molecular film. Energy dispersive x-ray spectroscopy (EDS) of LDEF exposed surfaces during secondary electron microscopy (SEM) of the samples confirmed contamination of the surfaces with Si and O. In general, particulates were not observed to develop from the contaminant overlayer on the exposed LDEF material surfaces. However, many SiO2 submicron particles were seen on a masked edge of an Ag/FEP blanket. In some cases such as the carbon fiber/organic matrix composites, interpretation of the contamination data was hindered by the lack of good laboratory controls. Examination of laboratory controls for the carbon fiber/Al alloy composites showed that preflight contamination was the most significant factor for all the contaminants generally detected at less than 1 atom percent, or detected only occasionally (i.e., all but Si, O, and C). Flight control surfaces, including sample backsides not exposed to space radiation or atomic oxygen flux, have accumulated some contamination on flight (compared to laboratory controls), but experimentally, the LDEF exposed surface contamination levels are generally higher for the contaminants Si and O. For most materials analyzed, Si contamination levels were higher on the leading edge surfaces than on the trailing edge surfaces. This was true even for the composite samples where considerable atomic oxygen erosion of the leading edge surfaces was observed by SEM. It is probable that the return flux associated with atmospheric backscatter resulted in enhanced deposition of silicones and other contaminants on the leading edge flight surfaces relative to the trailing edge. Although the Si concentration data suggested greater on-flight deposition of contaminants on the leading edge surfaces, the XPS analyses did not conclusively show different relative total thicknesses of flight deposited contamination for leading and trailing edge surfaces. It is possible that atomic oxygen reactions on the leading edge resulted in greater volatilization of the carbon component of the deposited silicones, effectively 'thinning' the leading edge deposited overlayer. Unlike other materials, exposed polymers such as Kapton and FEP-type Teflon had very low contamination on the leading edge surfaces. SEM evidence showed that undercutting of the contaminant overlayer and damaged polymer layers occurred during atomic oxygen erosion, which would enhance loss of material from the exposed surface.

Impact of mercury contamination on the population dynamics of Peringia ulvae (Gastropoda): Implications on metal transfer through the trophic web

NASA Astrophysics Data System (ADS)

Cardoso, P. G.; Sousa, E.; Matos, P.; Henriques, B.; Pereira, E.; Duarte, A. C.; Pardal, M. A.

2013-09-01

The effects of mercury contamination on the population structure and dynamics of the gastropod Peringia ulvae (also known as Hydrobia ulvae) and its impact on the trophic web were assessed along a mercury gradient in Ria de Aveiro (Portugal). The gastropod was revealed to be a tolerant species to the contaminant, since the highest densities, biomasses and growth productivity values were recorded at the intermediate contaminated area followed by the most contaminated one and finally the least contaminated area. P. ulvae was however negatively affected by mercury in terms of growth and life span. So, in the most contaminated area the population was characterised mainly by the presence of juveniles and young individuals. The intermediate contaminated area showed a greater equilibrium in terms of groups' proportion, being the adults the dominant set. The least contaminated area presented intermediate values. P. ulvae life spans were shortest in the most contaminated area (7-8 mo), followed by the least contaminated area (10-11 mo) and finally, the intermediate one (11-14 mo). P. ulvae revealed to be an important vehicle of mercury transfer from sediments to the trophic web, incorporating approximately 15 g of Hg, annually, in the inner area of the Laranjo Bay (0.6 Km2). Therefore, despite P. ulvae being revealed to be not a good bio-indicator of mercury contamination, since it did not suffer profound modifications in its structure and functioning, it is a crucial element in the mercury biomagnification processes throughout the food web.

Attractiveness of food and avoidance from contamination as conflicting stimuli to habitat selection by fish.

PubMed

Araújo, Cristiano V M; Rodríguez, Elizabeth N V; Salvatierra, David; Cedeño-Macias, Luis A; Vera-Vera, Victoria C; Moreira-Santos, Matilde; Ribeiro, Rui

2016-11-01

Habitat selection by fish is the outcome of a choice between different stimuli. Typically, the presence of food tends to attract organisms, while contamination triggers an avoidance response to prevent toxic effects. Given that both food and contaminants are not homogeneously distributed in the environment and that food can be available in contaminated zones, a key question has been put forward in the present study: does a higher availability of food in contaminated areas interfere in the avoidance response to contaminants regardless of the contamination level? Tilapia fry (Oreochromis sp.; 2.5-3.0 cm and 0.5-0.8 g) were exposed to two different effluent samples, diluted along a free-choice, non-forced exposure system simulating a contamination gradient. Initially, avoidance to the effluents was checked during a one hour exposure. Afterwards, food was added to the system so that the availability of food increased with the increase in the level of contamination, and the avoidance response to contamination was checked during another hour. Results clearly showed a concentration-dependent avoidance response for both effluents during the first hour (i.e., with no food). However, in presence of the food, the avoidance pattern was altered: organisms were propelled to intermittently move towards contaminated areas where food availability was higher. The incursions were taken regardless of the potential risk linked to the toxic effects. In conclusion, even when the risk of toxicity was imminent, tilapia fry were more intensively stimulated by the attractiveness of the food than by repulsion to the contamination. Copyright © 2016 Elsevier Ltd. All rights reserved.

A network biology-based approach to evaluating the effect of environmental contaminants on human interactome and diseases.

PubMed

Iida, M; Takemoto, K

2018-09-30

Environmental contaminant exposure can pose significant risks to human health. Therefore, evaluating the impact of this exposure is of great importance; however, it is often difficult because both the molecular mechanism of disease and the mode of action of the contaminants are complex. We used network biology techniques to quantitatively assess the impact of environmental contaminants on the human interactome and diseases with a particular focus on seven major contaminant categories: persistent organic pollutants (POPs), dioxins, polycyclic aromatic hydrocarbons (PAHs), pesticides, perfluorochemicals (PFCs), metals, and pharmaceutical and personal care products (PPCPs). We integrated publicly available data on toxicogenomics, the diseasome, protein-protein interactions (PPIs), and gene essentiality and found that a few contaminants were targeted to many genes, and a few genes were targeted by many contaminants. The contaminant targets were hub proteins in the human PPI network, whereas the target proteins in most categories did not contain abundant essential proteins. Generally, contaminant targets and disease-associated proteins were closely associated with the PPI network, and the closeness of the associations depended on the disease type and chemical category. Network biology techniques were used to identify environmental contaminants with broad effects on the human interactome and contaminant-sensitive biomarkers. Moreover, this method enabled us to quantify the relationship between environmental contaminants and human diseases, which was supported by epidemiological and experimental evidence. These methods and findings have facilitated the elucidation of the complex relationship between environmental exposure and adverse health outcomes. Copyright © 2018 Elsevier Inc. All rights reserved.

Does microbial contamination influence the success of the hematopoietic cell transplantation outcomes?

PubMed

Dal, Mehmet Sinan; Tekgündüz, Emre; Çakar, Merih Kızıl; Kaya, Ali Hakan; Namdaroğu, Sinem; Batgi, Hikmetullah; Bekdemir, Filiz; Uncu Ulu, Bahar; Yiğenoğlu, Tuğçe Nur; Kılınç, Ali; İskender, Dicle; Uğur, Bilge; Koçubaba, Şerife; İskender, Gülşen; Altuntaş, Fevzi

2016-08-01

Microbial contamination can be a marker for faulty process and is assumed to play an important role in the collection of hematopoietic progenitor cell (HPC) and infusion procedure. We aimed to determine the microbial contamination rates and evaluate the success of hematopoietic cell transplantation (HCT) in patients who received contaminated products. We analyzed microbial contamination records of HPC grafts between 2012 and 2015, retrospectively. Contamination rates of autologous donors were evaluated for at three steps: at the end of mobilization, following processing with dimethyl sulfoxide, and just before stem cell infusion. Grafts of allogeneic donors were assessed only before HCT. A total of 445 mobilization procedures were carried out on 333 (167 autologous and 166 allogeneic) donors. The microbiological contamination of peripheral blood (323/333 donations) and bone marrow (10/333 donations) products were analyzed. Bacterial contamination was detected in 18 of 1552 (1.15 %) culture bottles of 333 donors. During the study period 248 patients underwent HCT and among these patients microbial contamination rate on sample basis was 1.3 % (16/1212). Microbial contamination detected in nine patients (7 autologous; 2 allogeneic). In 8 of 9 patients, a febrile neutropenic attack was observed. The median day for the neutropenic fever was 4 days (0-9). None of the patients died within the post-transplant 30 days who received contaminated products. The use of contaminated products with antibiotic prophylaxis may be safe in terms of the first day of fever, duration of fever, neutrophil, platelet engraftment and duration of hospitalization. Copyright © 2016 Elsevier Ltd. All rights reserved.

Epidemiology of internal contamination with polonium-210 in the London incident, 2006.

PubMed

Fraser, G; Giraudon, I; Cohuet, S; Bishop, L; Maguire, H; Thomas, H L; Mandal, S; Anders, K; Sanchez-Padilla, E; Charlett, A; Evans, B; Gross, R

2012-02-01

More than 700 UK residents were tested for possible contamination with polonium-210 ((210)Po) following the alleged poisoning of Mr Alexander Litvinenko in London in November 2006. This paper describes the epidemiology of internal contamination with the radionuclide in this group. 11 locations in London had been identified as sufficiently environmentally contaminated with (210)Po to present a health risk to people associated with them. Public health consultant teams identified individuals at risk and offered 24-h urine testing for (210)Po excretion. Prevalence of internal contamination was estimated, and a retrospective cohort analysis was completed for each location. Overall 139 individuals (prevalence 0.19 (95% CI 0.13 to 0.27)) showed evidence of internal contamination with (210)Po, although none with uptakes likely to cause adverse health effects. Substantial prevalence was seen among specific hotel service staff, customers, staff and other users of a hotel bar, office and hospital staff, staff of one restaurant and residents of and visitors to the family home. Increased risks of contamination were seen for a hotel bar in association with occupational, behavioural and temporal factors. Occupational and guest exposure to contaminated areas of hotels were also associated with increased contamination risk. Nurses were more likely to become contaminated than other staff involved in direct patient care. Uptake of trace amounts of radionuclide in this incident was frequent. Occupational, behavioural and temporal gradients in contamination risk were mostly consistent with a priori site risk assessments. Utility of the investigation methods and findings for future accidental or deliberate environmental contamination incidents are discussed.

Optimal design of active spreading systems to remediate sorbing groundwater contaminants in situ

NASA Astrophysics Data System (ADS)

Piscopo, Amy N.; Neupauer, Roseanna M.; Kasprzyk, Joseph R.

2016-07-01

The effectiveness of in situ remediation to treat contaminated aquifers is limited by the degree of contact between the injected treatment chemical and the groundwater contaminant. In this study, candidate designs that actively spread the treatment chemical into the contaminant are generated using a multi-objective evolutionary algorithm. Design parameters pertaining to the amount of treatment chemical and the duration and rate of its injection are optimized according to objectives established for the remediation - maximizing contaminant degradation while minimizing energy and material requirements. Because groundwater contaminants have different reaction and sorption properties that influence their ability to be degraded with in situ remediation, optimization was conducted for six different combinations of reaction rate coefficients and sorption rates constants to represent remediation of the common groundwater contaminants, trichloroethene, tetrachloroethene, and toluene, using the treatment chemical, permanganate. Results indicate that active spreading for contaminants with low reaction rate coefficients should be conducted by using greater amounts of treatment chemical mass and longer injection durations relative to contaminants with high reaction rate coefficients. For contaminants with slow sorption or contaminants in heterogeneous aquifers, two different design strategies are acceptable - one that injects high concentrations of treatment chemical mass over a short duration or one that injects lower concentrations of treatment chemical mass over a long duration. Thus, decision-makers can select a strategy according to their preference for material or energy use. Finally, for scenarios with high ambient groundwater velocities, the injection rate used for active spreading should be high enough for the groundwater divide to encompass the entire contaminant plume.

Uptake and transport of radioactive nickel and cadmium into three vegetables after wet aerial contamination.

PubMed

Fismes, Joëlle; Echevarria, Guillaume; Leclerc-Cessac, Elisabeth; Morel, Jean Louis

2005-01-01

Knowledge of radionuclide or trace element retention and translocation to plants following an aerial contamination event, for example, sprinkling with contaminated water, is necessary for the evaluation of human exposure through consumption of contaminated vegetables. The fate of 63Ni and 109Cd in all plant parts of three different vegetables after wet deposition on leaves or on fruits was studied. Lettuce (Lactuca sativa L.), radish (Raphanus sativus L.), and bean (Phaseolus vulgaris L.) grown under controlled conditions in a growth chamber were contaminated with 63Ni and 109Cd either on leaves, by means of two different contamination methods (a single early contamination and a repetitive one), or on bean husks (third contamination method: a single contamination at a late stage). Spiked and nonspiked organs were harvested at maturity and radionuclide contents were measured. The fraction retained was on average 56% of the initially administered doses of 63Ni and 87% of 109Cd. The leaf-to-other organ translocation factor was considerably higher for 63Ni (on average 43% of retained radioactivity) than for 109Cd (8%). Nickel-63 migrated throughout the whole plant following foliar contamination, and mainly toward young leaves, seeds in formation, and sink organs, whereas 109Cd migrated to a much lesser extent and only to the organs that were closest to the spiked one, and not at all into fruit. After a fruit contamination event, both radionuclides were translocated into the seeds of spiked fruits. Radionuclide retention and translocation were not affected by plant species, but principally by the type of organ contaminated.

Processes of contaminant accumulation in an Arctic beluga whale population

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

Hickie, B.E.; Muir, D.; Kingsley, M.

1995-12-31

As long-lived top predators in marine food chains, marine mammals accumulate high levels of persistent organic contaminants. While arctic marine mammal contaminant concentrations are lower than those from temperate regions, levels are sufficiently high to be a health concern to people who rely on marine mammals as food. Monitoring programs developed to address this problem and to define spatial and temporal trends often are difficult to interpret since tissue contaminant concentrations vary with species, age, sex, reproductive effort, and condition (ie blubber thickness). It can be difficult to relate contaminant concentrations in other environmental compartments to those in marine mammalsmore » since their residues reflect exposure over their entire life, often 20 to 30 years. Contaminant accumulation models for marine mammals enable us to better understand the importance of, and interaction between, factors affecting contaminant accumulation, and can provide a dynamic framework for interpreting contaminant monitoring data. The authors developed two models for the beluga whale (Delphinapterus leucas): one provides a detailed view of processes at the individual level, the other examines population-based processes. The models quantify uptake, release and disposition of organic contaminants over their entire lifespan by incorporating all aspects of life-history. These models are used together to examine impact of a variety of factors on patterns and variability of PCBs found in the West Greenland beluga population (sample size: 696, 729). Factors examined include: energetics, growth, birth rate, lactation, contaminant assimilation and clearance rates, and dietary contaminant concentrations. Results are discussed in relation to the use of marine mammals for monitoring contaminant trends.« less

A partition-limited model for the plant uptake of organic contaminants from soil and water

USGS Publications Warehouse

Chiou, C.T.; Sheng, G.; Manes, M.

2001-01-01

In dealing with the passive transport of organic contaminants from soils to plants (including crops), a partition-limited model is proposed in which (i) the maximum (equilibrium) concentration of a contaminant in any location in the plant is determined by partition equilibrium with its concentration in the soil interstitial water, which in turn is determined essentially by the concentration in the soil organic matter (SOM) and (ii) the extent of approach to partition equilibrium, as measured by the ratio of the contaminant concentrations in plant water and soil interstitial water, ??pt (??? 1), depends on the transport rate of the contaminant in soil water into the plant and the volume of soil water solution that is required for the plant contaminant level to reach equilibrium with the external soil-water phase. Through reasonable estimates of plant organic-water compositions and of contaminant partition coefficients with various plant components, the model accounts for calculated values of ??pt in several published crop-contamination studies, including near-equilibrium values (i.e., ??pt ??? 1) for relatively water-soluble contaminants and lower values for much less soluble contaminants; the differences are attributed to the much higher partition coefficients of the less soluble compounds between plant lipids and plant water, which necessitates much larger volumes of the plant water transport for achieving the equilibrium capacities. The model analysis indicates that for plants with high water contents the plant-water phase acts as the major reservoir for highly water-soluble contaminants. By contrast, the lipid in a plant, even at small amounts, is usually the major reservoir for highly water-insoluble contaminants.

Mechanical impact tests of materials in oxygen effects of contamination. [Teflon, stainless steel, and aluminum

NASA Technical Reports Server (NTRS)

Ordin, P. M.

1980-01-01

The effect of contaminants on the mechanical impact sensitivity of Teflon, stainless steel, and aluminum in a high-pressure oxygen environment was investigated. Uncontaminated Teflon did not ignite under the test conditions. The liquid contaminants - cutting oil, motor lubricating oil, and toolmaker dye - caused Teflon to ignite. Raising the temperature lowered the impact energy required for ignition. Stainless steel was insensitive to ignition under the test conditions with the contaminants used. Aluminum appeared to react without contaminants under certain test conditions; however, contamination with cutting oil, motor lubricating oil, and toolmakers dye increased the sensitivity of aluminum to mechanical impact. The grit contaminants silicon dioxide and copper powder did not conclusively affect the sensitivity of aluminum.

Impact Of Groundwater Discharge On Contaminant Behavior In Sediments

EPA Science Inventory

The discharge of groundwater into surface water may influence the concentrations and availability of contaminants in sediments. There are three predominant pathways by which groundwater may affect the characteristics of contaminated sediments: 1) direct contribution of contamin...

CONTAMINANTS AND REMEDIAL OPTIONS AT PESTICIDE SITES

EPA Science Inventory

Many types of soils, sediments, and sludges are contaminated with a wide variety of pesticides. ite-specific characteristics such as volume to be treated, extent of contamination, and applicable cleanup goals differ greatly, and contaminant toxicity, migration pathways, persisten...

Corrective Action Decision Document/Closure Report for Corrective Action Unit 569: Area 3 Yucca Flat Atmospheric Test Sites Nevada National Security Site, Nevada with ROTC 1, Revision 0

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

Sloop, Christy

2013-04-01

This Corrective Action Decision Document/Closure Report presents information supporting the closure of Corrective Action Unit (CAU) 569: Area 3 Yucca Flat Atmospheric Test Sites, Nevada National Security Site, Nevada. CAU 569 comprises the following nine corrective action sites (CASs): • 03-23-09, T-3 Contamination Area • 03-23-10, T-3A Contamination Area • 03-23-11, T-3B Contamination Area • 03-23-12, T-3S Contamination Area • 03-23-13, T-3T Contamination Area • 03-23-14, T-3V Contamination Area • 03-23-15, S-3G Contamination Area • 03-23-16, S-3H Contamination Area • 03-23-21, Pike Contamination Area The purpose of this Corrective Action Decision Document/Closure Report is to provide justification and documentation supportingmore » the recommendation that no further corrective action is needed for CAU 569 based on the implementation of the corrective actions listed in Table ES-2.« less

Delineation of contaminant plume for an inorganic contaminated site using electrical resistivity tomography: comparison with direct-push technique.

PubMed

Liao, Qing; Deng, Yaping; Shi, Xiaoqing; Sun, Yuanyuan; Duan, Weidong; Wu, Jichun

2018-03-03

Precise delineation of contaminant plume distribution is essential for effective remediation of contaminated sites. Traditional in situ investigation methods like direct-push (DP) sampling are accurate, but are usually intrusive and costly. Electrical resistivity tomography (ERT) method, as a non-invasive geophysical technique to map spatiotemporal changes in resistivity of the subsurface, is becoming increasingly popular in environmental science. However, the resolution of ERT for delineation of contaminant plumes still remains controversial. In this study, ERT and DP technique were both conducted at a real inorganic contaminated site. The reliability of the ERT method was validated by the direct comparisons of their investigation results that the resistivity acquired by ERT method is in accordance with the total dissolved solid concentration in groundwater and the overall variation of the total iron content in soil obtained by DP technique. After testifying the applicability of ERT method for contaminant identification, the extension of contaminant plume at the study site was revealed by supplementary ERT surveys conducted subsequently in the surrounding area of the contaminant source zone.

Contaminant fate and transport in the Venice Lagoon: results from a multi-segment multimedia model.

PubMed

Sommerfreund, J K; Gandhi, N; Diamond, M L; Mugnai, C; Frignani, M; Capodaglio, G; Gerino, M; Bellucci, L G; Giuliani, S

2010-03-01

Contaminant loadings to the Venice Lagoon peaked from 1950s-1980s and although they have since declined, contaminant concentrations remain elevated in sediment and seafood. In order to identify the relative importance of contaminant sources, inter-media exchange and removal pathways, a modified 10-segment fugacity/aquivalence-based model was developed for octachlorodibenzodioxin/furan (OCDD/F), PCB-180, Pb and Cu in the Venice Lagoon. Results showed that in-place pollution nearby the industrial area, current industrial discharges, and tributary loadings were the main sources of contaminants to the lagoon, with negligible contributions from the atmosphere. The fate of these contaminants was governed by sediment-water exchange with simultaneous advective transport by water circulation. Contaminants circulated amongst the northern and central basins with a small fraction reaching the far southern basin and the Chioggia inlet. As a consequence, we estimated limited contaminant transfer to the Adriatic Sea, trapping the majority of contaminants in the sediment in this "average" circulation scenario which does not account for periodic flooding events. (c) 2009 Elsevier Inc. All rights reserved.

Simulation of Groundwater Contaminant Transport at a Decommissioned Landfill Site—A Case Study, Tainan City, Taiwan

PubMed Central

Chen, Chao-Shi; Tu, Chia-Huei; Chen, Shih-Jen; Chen, Cheng-Chung

2016-01-01

Contaminant transport in subsurface water is the major pathway for contamination spread from contaminated sites to groundwater supplies, to remediate a contaminated site. The aim of this paper was to set up the groundwater contaminant transport model for the Wang-Tien landfill site, in southwestern Taiwan, which exhibits high contamination of soil and groundwater and therefore represents a potential threat for the adjacent Hsu-Hsian Creek. Groundwater Modeling System software, which is the most sophisticated groundwater modeling tool available today, was used to numerically model groundwater flow and contaminant transport. In the simulation, the total mass of pollutants in the aquifer increased by an average of 72% (65% for ammonium nitrogen and 79% for chloride) after 10 years. The simulation produced a plume of contaminated groundwater that extends 80 m in length and 20 m in depth northeastward from the landfill site. Although the results show that the concentrations of ammonium nitrogen and chlorides in most parts are low, they are 3.84 and 467 mg/L, respectively, in the adjacent Hsu-Hsian Creek. PMID:27153078

DNAPL Managements Overview

DTIC Science & Technology

2007-04-01

characterizing groundwater contamination, In: Contaminated Soil (ConSoil), Thomas Telford, Leipzig, Germany , pp. 198-205. Rao, P.S.C. and J.W. Jawitz, 2003...installed to contain contamination, Keens Creek was rerouted to avoid passage through the contaminated site, new trees for phytoremediation and soil

IMPACT OF REDOX DISEQUILIBRIA ON CONTAMINANT TRANSPORT AND REMEDIATION IN SUBSURFACE SYSTEMS

EPA Science Inventory

Partitioning to mineral surfaces exerts significant control on inorganic contaminant transport in subsurface systems. Remedial technologies for in-situ treatment of subsurface contamination are frequently designed to optimize the efficiency of contaminant partitioning to solid s...

10 CFR 835.1101 - Control of material and equipment.

Code of Federal Regulations, 2010 CFR

2010-01-01

....1101 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Radioactive Contamination Control... section, material and equipment in contamination areas, high contamination areas, and airborne radioactivity areas shall not be released to a controlled area if: (1) Removable surface contamination levels on...

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.

40 CFR 143.3 - Secondary maximum contaminant levels.

Code of Federal Regulations, 2013 CFR

2013-07-01

.... 143.3 Section 143.3 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL SECONDARY DRINKING WATER REGULATIONS § 143.3 Secondary maximum contaminant levels. The secondary maximum contaminant levels for public water systems are as follows: Contaminant...

40 CFR 143.3 - Secondary maximum contaminant levels.

Code of Federal Regulations, 2011 CFR

2011-07-01

.... 143.3 Section 143.3 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL SECONDARY DRINKING WATER REGULATIONS § 143.3 Secondary maximum contaminant levels. The secondary maximum contaminant levels for public water systems are as follows: Contaminant...

40 CFR 143.3 - Secondary maximum contaminant levels.

Code of Federal Regulations, 2014 CFR

2014-07-01

.... 143.3 Section 143.3 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL SECONDARY DRINKING WATER REGULATIONS § 143.3 Secondary maximum contaminant levels. The secondary maximum contaminant levels for public water systems are as follows: Contaminant...

40 CFR 143.3 - Secondary maximum contaminant levels.

Code of Federal Regulations, 2012 CFR

2012-07-01

.... 143.3 Section 143.3 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL SECONDARY DRINKING WATER REGULATIONS § 143.3 Secondary maximum contaminant levels. The secondary maximum contaminant levels for public water systems are as follows: Contaminant...

Presentations from the Fourth Unregulated Contaminant Monitoring Rule (UCMR 4) Methods Stakeholder Meeting on May 15, 2013

EPA Pesticide Factsheets

This document contains the presentations from the Unregulated Contaminant Monitoring Rule 4 Methods Stakeholder Meeting held on May 15, 2013 about the Contaminant Candidate List (CCL) and the Unregulated Contaminant Monitoring Rule.

TOOLS FOR ASSESSING MONITORED NATURAL RECOVERY OF PCB-CONTAMINATED SEDIMENTS

EPA Science Inventory

Management of contaminated sediments poses many challenges due to varied contaminants and volumes of sediments to manage. dredging, capping, and monitored natural recovery (MNR) are the primary approaches at this time for managing contaminated sediment risks. Understanding how we...

Microarray technology for major chemical contaminants analysis in food: current status and prospects.

PubMed

Zhang, Zhaowei; Li, Peiwu; Hu, Xiaofeng; Zhang, Qi; Ding, Xiaoxia; Zhang, Wen

2012-01-01

Chemical contaminants in food have caused serious health issues in both humans and animals. Microarray technology is an advanced technique suitable for the analysis of chemical contaminates. In particular, immuno-microarray approach is one of the most promising methods for chemical contaminants analysis. The use of microarrays for the analysis of chemical contaminants is the subject of this review. Fabrication strategies and detection methods for chemical contaminants are discussed in detail. Application to the analysis of mycotoxins, biotoxins, pesticide residues, and pharmaceutical residues is also described. Finally, future challenges and opportunities are discussed.

Riparian spiders indicate the magnitude and sources of polychlorinated biphenyl (PCB) contamination at a large contaminated sediment site

USGS Publications Warehouse

Walters, David M.; Otter, Ryan R.; Kraus, Johanna M.; Mills, Marc A.

2018-01-01

We investigated PCB contamination at the Ashtabula River Area of Concern (AOC) following remedial dredging using araneid and tetragnathid spiders. PCB concentrations remain elevated in the AOC compared to reference conditions. Patterns of contamination were strikingly similar between taxa, but were higher in tetragnathids at the most contaminated sites. Spider PCB homolog distributions identified two PCB sources to the AOC. Based on these findings, we recommend situations where these taxa can be used singularly, in concert, or combined into a composite “spider” sample to assess environmental contamination. 

Surface cleanliness measurement procedure

DOEpatents

Schroder, Mark Stewart; Woodmansee, Donald Ernest; Beadie, Douglas Frank

2002-01-01

A procedure and tools for quantifying surface cleanliness are described. Cleanliness of a target surface is quantified by wiping a prescribed area of the surface with a flexible, bright white cloth swatch, preferably mounted on a special tool. The cloth picks up a substantial amount of any particulate surface contamination. The amount of contamination is determined by measuring the reflectivity loss of the cloth before and after wiping on the contaminated system and comparing that loss to a previous calibration with similar contamination. In the alternative, a visual comparison of the contaminated cloth to a contamination key provides an indication of the surface cleanliness.

Tools for measuring surface cleanliness

DOEpatents

Schroder, Mark Stewart; Woodmansee, Donald Ernest; Beadie, Douglas Frank

2002-01-01

A procedure and tools for quantifying surface cleanliness are described. Cleanliness of a target surface is quantified by wiping a prescribed area of the surface with a flexible, bright white cloth swatch, preferably mounted on a special tool. The cloth picks up a substantial amount of any particulate surface contamination. The amount of contamination is determined by measuring the reflectivity loss of the cloth before and after wiping on the contaminated system and comparing that loss to a previous calibration with similar contamination. In the alternative, a visual comparison of the contaminated cloth to a contamination key provides an indication of the surface cleanliness.

Solid materials for removing metals and fabrication method

DOEpatents

Coronado, Paul R.; Reynolds, John G.; Coleman, Sabre J.

2004-10-19

Solid materials have been developed to remove contaminating metals and organic compounds from aqueous media. The contaminants are removed by passing the aqueous phase through the solid materials which can be in molded, granular, or powder form. The solid materials adsorb the metals and the organics leaving a purified aqueous stream. The materials are sol-gel and or sol-gel and granulated activated carbon (GAC) mixtures. The species-specific adsorption occurs through specific chemical modifications of the solids tailored towards the contaminant(s). The contaminated solid materials can then be disposed of or the contaminant can be removed and the solids recycled.

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.

Issues and Effects of Atomic Oxygen Interactions With Silicone Contamination on Spacecraft in Low Earth Orbit

NASA Technical Reports Server (NTRS)

Banks, Bruce; Rutledge, Sharon; Sechkar, Edward; Stueber, Thomas; Snyder, Aaron; deGroh, Kim; Haytas, Christy; Brinker, David

2000-01-01

The continued presence and use of silicones on spacecraft in low Earth orbit (LEO) has been found to cause the deposition of contaminant films on surfaces which are also exposed to atomic oxygen. The composition and optical properties of the resulting SiO(x)- based (where x is near 2) contaminant films may be dependent upon the relative rates of arrival of atomic oxygen, silicone contaminant and hydrocarbons. This paper presents results of in-space silicone contamination tests, ground laboratory simulation tests and analytical modeling to identify controlling processes that affect contaminant characteristics.

Functional gene array-based analysis of microbial community structure in groundwaters with a gradient of contaminant levels

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

Waldron, P.J.; Wu, L.; Van Nostrand, J.D.

2009-06-15

To understand how contaminants affect microbial community diversity, heterogeneity, and functional structure, six groundwater monitoring wells from the Field Research Center of the U.S. Department of Energy Environmental Remediation Science Program (ERSP; Oak Ridge, TN), with a wide range of pH, nitrate, and heavy metal contamination were investigated. DNA from the groundwater community was analyzed with a functional gene array containing 2006 probes to detect genes involved in metal resistance, sulfate reduction, organic contaminant degradation, and carbon and nitrogen cycling. Microbial diversity decreased in relation to the contamination levels of the wells. Highly contaminated wells had lower gene diversity butmore » greater signal intensity than the pristine well. The microbial composition was heterogeneous, with 17-70% overlap between different wells. Metal-resistant and metal-reducing microorganisms were detected in both contaminated and pristine wells, suggesting the potential for successful bioremediation of metal-contaminated groundwaters. In addition, results of Mantel tests and canonical correspondence analysis indicate that nitrate, sulfate, pH, uranium, and technetium have a significant (p < 0.05) effect on microbial community structure. This study provides an overall picture of microbial community structure in contaminated environments with functional gene arrays by showing that diversity and heterogeneity can vary greatly in relation to contamination.« less

Comparison of methods to control floor contamination in an animal research facility.

PubMed

Allen, Kenneth P; Csida, Tarrant; Leming, Jeaninne; Murray, Kathleen; Gauld, Stephen B; Thulin, Joseph

2012-10-01

The authors evaluated the effectiveness of adhesive mats, contamination control flooring, and shoe covers in decreasing the presence of microbial agents on animal holding room floors and footwear. Swab samples taken from animal holding room floors after the use of each product were compared with samples taken from rooms after no products were used. Swab samples were also taken from the heels and soles of the footwear of animal care staff before and after use of each product. The use of contamination control flooring or shoe covers significantly reduced the amount of organic material (as indicated by ATP levels measured by a luminometer) present on floors. Bacterial and ATP contamination of footwear was significantly lower after the use of shoe covers than after the use of adhesive mats or contamination control flooring, and the use of shoe covers led to a greater decrease in contamination before and after use than did use of either of the other two products. Although shoe covers were superior to both adhesive mats and contamination control flooring for decreasing contamination of animal room floors and footwear, facilities must take into account the contamination control standards required, the cost of the product, and the labor and time associated with product use when deciding which contamination control practices to implement.

Heavy Metal Contamination Assessment and Partition for Industrial and Mining Gathering Areas

PubMed Central

Guan, Yang; Shao, Chaofeng; Ju, Meiting

2014-01-01

Industrial and mining activities have been recognized as the major sources of soil heavy metal contamination. This study introduced an improved Nemerow index method based on the Nemerow and geo-accumulation index. Taking a typical industrial and mining gathering area in Tianjin (China) as example, this study then analyzed the contamination sources as well as the ecological and integrated risks. The spatial distribution of the contamination level and ecological risk were determined using Geographic Information Systems. The results are as follows: (1) Zinc showed the highest contaminant level in the study area; the contamination levels of the other seven heavy metals assessed were relatively lower. (2) The combustion of fossil fuels and emissions from industrial and mining activities were the main sources of contamination in the study area. (3) The overall contamination level of heavy metals in the study area ranged from heavily contaminated to extremely contaminated and showed an uneven distribution. (4) The potential ecological risk showed an uneven distribution, and the overall ecological risk level ranged from low to moderate. This study also emphasized the importance of partition in industrial and mining areas, the extensive application of spatial analysis methods, and the consideration of human health risks in future studies. PMID:25032743

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.

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.

Effects of electrocardiography contamination and comparison of ECG removal methods on upper trapezius electromyography recordings.

PubMed

Marker, Ryan J; Maluf, Katrina S

2014-12-01

Electromyography (EMG) recordings from the trapezius are often contaminated by the electrocardiography (ECG) signal, making it difficult to distinguish low-level muscle activity from muscular rest. This study investigates the influence of ECG contamination on EMG amplitude and frequency estimations in the upper trapezius during muscular rest and low-level contractions. A new method of ECG contamination removal, filtered template subtraction (FTS), is described and compared to 30 Hz high-pass filter (HPF) and averaged template subtraction (ATS) methods. FTS creates a unique template of each ECG artifact using a low-pass filtered copy of the contaminated signal, which is subtracted from contaminated periods in the original signal. ECG contamination results in an over-estimation of EMG amplitude during rest in the upper trapezius, with negligible effects on amplitude and frequency estimations during low-intensity isometric contractions. FTS and HPF successfully removed ECG contamination from periods of muscular rest, yet introduced errors during muscle contraction. Conversely, ATS failed to fully remove ECG contamination during muscular rest, yet did not introduce errors during muscle contraction. The relative advantages and disadvantages of different ECG contamination removal methods should be considered in the context of the specific motor tasks that require analysis. Copyright © 2014 Elsevier Ltd. All rights reserved.

Bioremediation of Uranium-Contaminated Groundwater using Engineered Injection and Extraction

NASA Astrophysics Data System (ADS)

Greene, J. A.; Neupauer, R.; Ye, M.; Kasprzyk, J. R.; Mays, D. C.; Curtis, G. P.

2017-12-01

During in-situ remediation of contaminated groundwater, a treatment chemical is injected into the contaminated groundwater to react with and degrade the contaminant, with reactions occurring where the treatment chemical contacts the contaminant. Traditional in-situ groundwater remediation relies on background groundwater flow for spreading of treatment chemicals into contaminant plumes. Engineered Injection and Extraction (EIE), in which time-varying induced flow fields are used to actively spread the treatment chemical into the contaminant plume, has been developed to increase contact between the contaminant and treatment chemical, thereby enhancing contaminant degradation. EIE has been investigated for contaminants that degrade through irreversible bimolecular reaction with a treatment chemical, but has not been investigated for a contaminant governed by reversible reactions. Uranium primarily occurs in its aqueous, mobile form, U(VI), in the environment but can be bioreduced to its sparingly soluble, immobile form, U(IV), by iron reducing bacteria stimulated by an acetate amendment. In this study, we investigate the ability of EIE to facilitate and sustain favorable conditions to immobilize uranium during remediation, and to prevent re-mobilization of uranium into the aqueous phase after active remediation has ended. Simulations in this investigation are conducted using a semi-synthetic model based on physical and chemical conditions at the Naturita Uranium Mill Tailings Remedial Action (UMTRA) site in southwestern Colorado and the Old Rifle UMTRA site in western Colorado. The EIE design is optimized for the synthetic model using the Borg multi-objective evolutionary algorithm.

Analysis of predictors related to soil contamination in recreational areas of Romania.

PubMed

Gagiu, C; Pica, E M; Querol, X; Botezan, C S

2015-12-01

Soil contamination in recreational areas can considerably affect children's health, as they are the segment of the population most sensitive to anthropogenic contamination. Soil contamination in recreational areas is influenced by a number of factors such as type and age of the recreational area, nearby traffic intensity, proximity to industrial areas, presence of vegetation, level of usage, treated wood structures, and the extent of maintenance operations carried out in the area. These can most often be observed during a simple site visit. The purpose of the present research is to analyze to which extent the presence of these factors can trigger an alarm signal, highlighting soil contamination in urban recreational areas. In this regard, soil contamination was scaled using the integrated pollution index applied on nine distinctive contaminants (As, Cu, Cd, Zn, Pb, Hg, Co, Ni, Mg) identified using inductively coupled plasma mass spectrometry (ICP-MS). Multiple linear regression analysis was performed in order to assess predictors of soil contamination. The research was carried out in a number of 88 recreational areas, parks, and playgrounds from 19 Romanian cities, revealing the fact that proximity to industrial areas and intensive traffic had statistically significant effects on soil contamination. Furthermore, it was observed that in 78 out of the 88 analyzed locations, the concentrations of contaminants exceeded the guidelines established through national legislation, thus confirming the presumption that high concentrations of contaminants exist in the parks and playgrounds of Romania.

Assessment of the risk of medium-term internal contamination in Minamisoma City, Fukushima, Japan, after the Fukushima Dai-ichi nuclear accident.

PubMed

Sugimoto, Amina; Gilmour, Stuart; Tsubokura, Masaharu; Nomura, Shuhei; Kami, Masahiro; Oikawa, Tomoyoshi; Kanazawa, Yukio; Shibuya, Kenji

2014-06-01

The Fukushima Dai-ichi nuclear disaster, the first level-7 major nuclear disaster since Chernobyl, raised concerns about the future health consequences of exposure to and intake of radionuclides. Factors determining the risk and level of internal radiation contamination after a nuclear accident, which are a key to understanding and improving current nuclear disaster management, are not well studied. We investigated both the prevalence and level of internal contamination in residents of Minamisoma, and identified factors determining the risk and levels of contamination. We implemented a program assessing internal radiation contamination using a whole body counter (WBC) measurement and a questionnaire survey in Minamisoma, between October 2011 and March 2012. Approximately 20% of the city's population (8,829 individuals) participated in the WBC measurement for internal contamination, of which 94% responded to the questionnaire. The proportion of participants with detectable internal contamination was 40% in adults and 9% in children. The level of internal contamination ranged from 2.3 to 196.5 Bq/kg (median, 11.3 Bq/kg). Tobit regression analysis identified two main risk factors: more time spent outdoors, and intake of potentially contaminated foods and water. Our findings suggest that, with sensible and reasonable precautions, people may be able to live continuously in radiation-affected areas with limited contamination risk. To enable this, nuclear disaster response should strictly enforce food and water controls and disseminate evidence-based and up-to-date information about avoidable contamination risks.

Forensic Application of Microbiological Culture Analysis To Identify Mail Intentionally Contaminated with Bacillus anthracis Spores†

PubMed Central

Beecher, Douglas J.

2006-01-01

The discovery of a letter intentionally filled with dried Bacillus anthracis spores in the office of a United States senator prompted the collection and quarantine of all mail in congressional buildings. This mail was subsequently searched for additional intentionally contaminated letters. A microbiological sampling strategy was used to locate heavy contamination within the 642 separate plastic bags containing the mail. Swab sampling identified 20 bags for manual and visual examination. Air sampling within the 20 bags indicated that one bag was orders of magnitude more contaminated than all the others. This bag contained a letter addressed to Senator Patrick Leahy that had been loaded with dried B. anthracis spores. Microbiological sampling of compartmentalized batches of mail proved to be efficient and relatively safe. Efficiency was increased by inoculating culture media in the hot zone rather than transferring swab samples to a laboratory for inoculation. All mail sampling was complete within 4 days with minimal contamination of the sampling environment or personnel. However, physically handling the intentionally contaminated letter proved to be exceptionally hazardous, as did sorting of cross-contaminated mail, which resulted in generation of hazardous aerosol and extensive contamination of protective clothing. Nearly 8 × 106 CFU was removed from the most highly cross-contaminated piece of mail found. Tracking data indicated that this and other heavily contaminated envelopes had been processed through the same mail sorting equipment as, and within 1 s of, two intentionally contaminated letters. PMID:16885280

The incidence of blood contamination of lead unit dose containers with and without single-use protective inserts used with commercially prepared radiopharmaceutical unit doses.

PubMed

Pickett, M W; Kosegi, J E; Thomas, K S; Waterstram-Rich, K M

1998-09-01

This investigation evaluated the effectiveness of disposable plastic inserts in radiopharmaceutical unit dose lead containers (pigs) in preventing the distribution of doses in blood-contaminated containers. Technologists commonly dispose of the syringes by placing them into the lead pigs, leaving the needles uncapped. This process raises the question of unsuspected blood contamination of these pigs. Consequently, the distribution of commercially prepared radiopharmaceutical doses in reusable lead pigs may result in radiopharmaceutical doses being distributed in containers that are contaminated with blood. Using a simple chemical wipe test designed to determine the presence or absence of blood contamination, 618 pigs from commercial radiopharmacies throughout the U.S. were tested for contamination. The inside of the pigs and inserts, if present, were wiped before and after dose administration. Of the pigs tested, 292 came from radiopharmacies that used a protective, disposable plastic insert inside the pig, and 326 came from radiopharmacies that did not use an insert. Of those pigs without the protective disposable inserts, 39.3% arrived in the nuclear medicine department in pigs contaminated with blood. Of those pigs with inserts, 1% arrived with blood-contaminated inserts. After dose administration, 46.3% of the pigs without inserts were contaminated with blood and 3% of the protective inserts were contaminated. The proper use of disposable plastic inserts reduces the possibility of distributing radiopharmaceutical unit doses in containers contaminated with blood.

Some Case Studies on Metal-Microbe Interactions to Remediate Heavy Metals- Contaminated Soils in Korea

NASA Astrophysics Data System (ADS)

Chon, Hyo-Taek

2015-04-01

Conventional physicochemical technologies to remediate heavy metals-contaminated soil have many problems such as low efficiency, high cost and occurrence of byproducts. Recently bioremediation technology is getting more and more attention. Bioremediation is defined as the use of biological methods to remediate and/or restore the contaminated land. The objectives of bioremediation are to degrade hazardous organic contaminants and to convert hazardous inorganic contaminants to less toxic compounds of safe levels. The use of bioremediation in the treatment of heavy metals in soils is a relatively new concept. Bioremediation using microbes has been developed to remove toxic heavy metals from contaminated soils in laboratory scale to the contaminated field sites. Recently the application of cost-effective and environment-friendly bioremediation technology to the heavy metals-contaminated sites has been gradually realized in Korea. The merits of bioremediation include low cost, natural process, minimal exposure to the contaminants, and minimum amount of equipment. The limitations of bioremediation are length of remediation, long monitoring time, and, sometimes, toxicity of byproducts for especially organic contaminants. From now on, it is necessary to prove applicability of the technologies to contaminated sites and to establish highly effective, low-cost and easy bioremediation technology. Four categories of metal-microbe interactions are generally biosorption, bioreduction, biomineralization and bioleaching. In this paper, some case studies of the above metal-microbe interactions in author's lab which were published recently in domestic and international journals will be introduced and summarized.

A randomized trial of povidone-iodine compared with iodine tincture for venipuncture site disinfection: effects on rates of blood culture contamination.

PubMed

Little, J R; Murray, P R; Traynor, P S; Spitznagel, E

1999-08-01

Contamination of blood cultures creates problems in their interpretation and unneeded resource utilization. Because skin flora comprise the major group of contaminant species, more effective skin disinfection at the venipuncture site could reduce contamination. We performed a randomized trial in adult inpatients at a tertiary care teaching hospital. Antecubital venipuncture sites were randomly disinfected with povidone-iodine or iodine tincture, and blood cultures (two bottles, 10 mL of blood) were drawn by professional phlebotomists. Scoring of contaminant species was restricted to skin flora. Hospital resource utilization was compared among patients with contaminated blood cultures and those with sterile blood cultures. Of the 3,851 blood cultures collected during the study, 120 (3.1%) were contaminated with skin flora. The contamination rate for blood cultures collected after povidone-iodine was 3.8% (74 of 1,947), compared with a rate of 2.4% (46 of 1,904, P = 0.01) after iodine tincture. The difference in mean total hospital costs for patients with contaminated blood cultures and those with sterile blood cultures was $4,100 (95% confidence interval: $740 to $7,400, P = 0.02). Iodine tincture is superior to povidone-iodine for venipuncture site antisepsis before blood culture sampling. Because of the high costs associated with contaminated blood cultures, hospitals should consider switching from povidone-iodine to iodine tincture. Reduction of the contamination rate may improve the quality of patient care and reduce hospital costs.

Adverse morphological development in embryonic zebrafish exposed to environmental concentrations of contaminants individually and in mixture.

PubMed

Kinch, Cassandra D; Kurrasch, Deborah M; Habibi, Hamid R

2016-06-01

Exposure to environmental contaminants has been linked to developmental and reproductive abnormalities leading to infertility, spontaneous abortion, reduced number of offspring, and metabolic disorders. In addition, there is evidence linking environmental contaminants and endocrine disruption to abnormal developmental rate, defects in heart and eye morphology, and alterations in behavior. Notably, these effects could not be explained by interaction with a single hormone receptor. Here, using a whole-organism approach, we investigated morphological changes to developing zebrafish caused by exposure to a number of environmental contaminants, including bisphenol A (BPA), di(2-ethylhexyl)phthalate (DEHP), nonylphenol, and fucosterol at concentrations measured in a local water body (Oldman River, AB), individually and in mixture. Exposure to nanomolar contaminant concentrations resulted in abnormal morphological development, including changes to body length, pericardia (heart), and the head. We also characterize the spatiotemporal expression profiles of estrogen, androgen, and thyroid hormone receptors to demonstrate that localization of these receptors might be mediating contaminant effects on development. Finally, we examined the effects of contaminants singly and in mixture. Combined, our results support the hypothesis that adverse effects of contaminants are not mediated by single hormone receptor signaling, and adversity of contaminants in mixture could not be predicted by simple additive effect of contaminants. The findings provide a framework for better understanding of developmental toxicity of environmental contaminants in zebrafish and other vertebrate species. Copyright © 2016 Elsevier B.V. All rights reserved.

The effects of feed-borne Fusarium mycotoxins and glucomannan in turkey poults based on specific and non-specific parameters.

PubMed

Devreese, Mathias; Girgis, George N; Tran, Si-Trung; De Baere, Siegrid; De Backer, Patrick; Croubels, Siska; Smith, Trevor K

2014-01-01

An experiment was conducted to investigate the effects of feeding grains naturally contaminated with Fusarium mycotoxins and a yeast derived glucomannan mycotoxin adsorbent (GMA) on selected specific and non-specific parameters in turkey poults. Two hundred and forty 1-day-old male turkey poults were fed the experimental diets for twelve weeks. Experimental diets were formulated with control grains, control grains+0.2% GMA, naturally-contaminated grains, or naturally-contaminated grains+0.2% GMA. Deoxynivalenol (DON) was the major contaminant of the contaminated grains and concentrations varied from 4.0 to 6.5 mg/kg in the contaminated diets. Non-specific parameters measured included: performance parameters, plasma biochemistry profiles, morphometry and CD8(+) T-lymphocyte counts in the duodenum. Plasma concentrations of DON and de-epoxydeoxynivalenol (DOM-1) were used as specific parameters. Performance parameters and plasma biochemistry were altered by the feeding of contaminated diets and GMA but this was not consistent throughout the trial. The feeding of contaminated diets reduced duodenal villus height and apparent villus surface area. This effect was prevented by GMA supplementation. The feeding of contaminated diets elevated total duodenal CD8(+) T-lymphocyte counts but this effect was not prevented by GMA. No significant differences were seen in plasma concentrations of DON and DOM-1 comparing birds fed contaminated and contaminated+GMA diets suggesting that GMA did not prevent DON absorption under these conditions. Copyright © 2013 Elsevier Ltd. All rights reserved.

Process for treating waste water having low concentrations of metallic contaminants

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

Looney, Brian B; Millings, Margaret R; Nichols, Ralph L

A process for treating waste water having a low level of metallic contaminants by reducing the toxicity level of metallic contaminants to an acceptable level and subsequently discharging the treated waste water into the environment without removing the treated contaminants.

ENGINEERING BULLETIN: SEPARATION/CONCENTRATION TECHNOLOGY ALTERNATIVES FOR THE REMEDIATION OF PESTICIDE-CONTAMINATED SOIL

EPA Science Inventory

Pesticide contamination includes a wide variety of compounds and may result from manufacturing improper storage, handling, disposal; or agricultural processes. It can occur in soil and can lead to secondary contamination of groundwater. Remediation of pesticide-contaminated soils...

RESPONDING TO THREATS AND INCIDENTS OF INTENTIONAL DRINKING WATER CONTAMINATION

EPA Science Inventory

All drinking water systems have some degree of vulnerability to contamination, and analysis shows that it is possible to contaminate drinking water at levels causing varying degrees of harm. Furthermore, experience indicates that the threat of contamination, overt or circumstant...

Biofilm formation and ethanol inhibition by bacterial contaminants of biofuel fermentation

USDA-ARS?s Scientific Manuscript database

Bacterial contaminants can inhibit ethanol production in biofuel fermentations, and even result in stuck fermentations. Contaminants may persist in production facilities by forming recalcitrant biofilms. A two-year longitudinal study was conducted of bacterial contaminants from a Midwestern dry grin...

The Accumulation of Radioactive Contaminants in Drinking Water Distribution Systems

EPA Science Inventory

The accumulation of trace contaminants in drinking water distribution systems has been documented and the subsequent release of the contaminants back to the water is a potential exposure pathway. Radioactive contaminants are of particular concern because of their known health eff...

Recalls of foods due to microbiological contamination classified by the U.S. Food and Drug Administration, fiscal years 2003 through 2011.

PubMed

Dey, Manashi; Mayo, Jonathan A; Saville, Deborah; Wolyniak, Cecilia; Klontz, Karl C

2013-06-01

Recalls of foods contaminated with pathogens help reduce the transmission of infectious diseases. Here, we summarize the number and nature of foods recalled as a result of microbiological contamination, classified by the U.S. Food and Drug Administration for the period 1 October 2002 through 30 September 2011. Microbiological contamination accounted for 1,395 (42%) of 3,360 recalls of food during this period. Nuts and edible seeds, followed by fishery-seafood products and spices, were the types of products most commonly recalled for microbiological contamination. Salmonella contamination accounted for the greatest number of food products recalled due to microbiological contamination, and was the pathogen most often linked to reported outbreaks involving recalled food products.

Verification of surface preparation for adhesive bonding

NASA Technical Reports Server (NTRS)

Myers, Rodney S.

1995-01-01

A survey of solid rocket booster (SRB) production operations identified potential contaminants which might adversely affect bonding operations. Lap shear tests quantified these contaminants' effects on adhesive strength. The most potent contaminants were selected for additional studies on SRB thermal protection system (TPS) bonding processes. Test panels were prepared with predetermined levels of contamination, visually inspected using white and black light, then bonded with three different TPS materials over the unremoved contamination. Bond test data showed that white and black light inspections are adequate inspection methods for TPS bonding operations. Extreme levels of contamination (higher than expected on flight hardware) had an insignificant effect on TPS bond strengths because of the apparent insensitivity of the adhesive system to contamination effects, and the comparatively weak cohesive strength of the TPS materials.

Groundwater contaminant science activities of the U.S. Geological Survey in New England

USGS Publications Warehouse

Weiskel, Peter K.

2016-03-23

Aquifers in New England provide water for human needs and natural ecosystems. In some areas, however, aquifers have been degraded by contaminants from geologic and human sources. In recent decades, the U.S. Geological Survey has been a leader in describing contaminant occurrence in the bedrock and surficial aquifers of New England. In cooperation with Federal, State, and local agencies, the U.S. Geological Survey has also studied the vulnerability of groundwater to contaminants, the factors affecting the geographic distribution of contaminants, and the geochemical processes controlling contaminant transport and fate. This fact sheet describes some of the major science needs in the region related to groundwater contaminants and highlights recent U.S. Geological Survey studies that provide a foundation for future investigations.

Evaluation of certain contaminants in food.

PubMed

2017-01-01

This report represents the conclusions of a Joint FAO/WHO Expert Committee convened to evaluate the safety of various contaminants or groups of contaminants in food. The first part of the report contains a brief description of general considerations addressed at the meeting, including updates on matters of interest to the work of the Committee. A summary follows of the Committee’s evaluations of technical, toxicological and/or dietary exposure data for six contaminants or groups of contaminants (aflatoxins, 4,15-diacetoxyscirpenol, fumonisins, glycidyl esters, 3-MCPD esters and 3-MCPD, sterigmatocystin) as well as an evaluation of co-exposure of fumonisins with aflatoxins. Annexed to the report is a summary of the toxicological and dietary exposure information as well as the Committee’s recommendations on the contaminants and groups of contaminants considered at this meeting.

Contamination of lithium heparin blood by K2-ethylenediaminetetraacetic acid (EDTA): an experimental evaluation.

PubMed

Lima-Oliveira, Gabriel; Salvagno, Gian Luca; Danese, Elisa; Brocco, Giorgio; Guidi, Gian Cesare; Lippi, Giuseppe

2014-01-01

The contamination of serum or lithium heparin blood with ethylenediaminetetraacetic acid (EDTA) salts may affect accuracy of some critical analytes and jeopardize patient safety. The aim of this study was to evaluate the effect of lithium heparin sample contamination with different amounts of K2EDTA. Fifteen volunteers were enrolled among the laboratory staff. Two lithium heparin tubes and one K2EDTA tube were collected from each subject. The lithium-heparin tubes of each subject were pooled and divided in 5 aliquots. The whole blood of K2EDTA tube was then added in scalar amount to autologous heparinised aliquots, to obtained different degrees of K2EDTA blood volume contamination (0%; 5%; 13%; 29%; 43%). The following clinical chemistry parameters were then measured in centrifuged aliquots: alanine aminotranspherase (ALT), bilirubin (total), calcium, chloride, creatinine, iron, lactate dehydrogenase (LD), lipase, magnesium, phosphate, potassium, sodium. A significant variation starting from 5% K2EDTA contamination was observed for calcium, chloride, iron, LD, magnesium (all decreased) and potassium (increased). The variation of phosphate and sodium (both increased) was significant after 13% and 29% K2EDTA contamination, respectively. The values of ALT, bilirubin, creatinine and lipase remained unchanged up to 43% K2EDTA contamination. When variations were compared with desirable quality specifications, the bias was significant for calcium, chloride, LD, magnesium and potassium (from 5% K2EDTA contamination), sodium, phosphate and iron (from 29% K2EDTA contamination). The concentration of calcium, magnesium, potassium, chloride and LD appears to be dramatically biased by even modest K2EDTA contamination (i.e., 5%). The values of iron, phosphate, and sodium are still reliable up to 29% K2EDTA contamination, whereas ALT, bilirubin, creatinine and lipase appear overall less vulnerable towards K2EDTA contamination.

Spatial distribution of Cd and Cu in soils in Shenyang Zhangshi Irrigation Area (SZIA), China*

PubMed Central

Sun, Li-na; Yang, Xiao-bo; Wang, Wen-qing; Ma, Li; Chen, Su

2008-01-01

Heavy metal contamination of soils, derived from sewage irrigation, mining and inappropriate utilization of various agrochemicals and pesticides, and so on, has been of wide concern in the last several decades. The Shenyang Zhangshi Irrigation Area (SZIA) in China is a representative area of heavy metal contamination of soils resulting from sewage irrigation for about 30 years. This study investigated the spatial distribution and temporal variation of soil cadmium (Cd) and copper (Cu) contamination in the SZIA. The soil samples were collected from the SZIA in 1990 and 2004; Cd and Cu in soils was analyzed and then the spatial distribution and temporal variation of Cd and Cu in soils were modeled using Kriging methods. The results show that long-term sewage irrigation had caused serious Cd and Cu contamination in soils. The mean and the maximum of soil Cd are markedly higher than the levels in second grade standard soil (LSGSS) in China, and the maximum of soil Cu is close to the LSGSS in China in 2004 and is more than the LSGSS in China in 1990. The contamination magnitude of soil Cd and the soil extent of Cd contamination had evidently increased since sewage irrigation ceased in 1992. The contamination magnitude of soil Cu and the soil extent of Cu contamination had evidently increased in topsoil, but obviously decresed in subsoil. The soil contamination of Cd and Cu was mainly related to Cd and Cu reactivation of contaminated sediments in Shenyang Xi River and the import of Cd and Cu during irrigation. The eluviation of Cd and Cu in contaminated topsoil with rainfall and irrigation water was another factor of temporal-spatial variability of Cd and Cu contamination in soils. PMID:18357631

A meta-analysis of the rates of Staphylococcus aureus and methicillin-resistant S aureus contamination on the surfaces of environmental objects that health care workers frequently touch.

PubMed

Lin, Dongxin; Ou, Qianting; Lin, Jialing; Peng, Yang; Yao, Zhenjiang

2017-04-01

Health care workers may potentially spread Staphylococcus aureus and methicillin-resistant S aureus (MRSA) to patients by contaminated high-touch items. We aimed to determine the pooled rates of S aureus and MRSA contamination and influencing factors. A literature search of the PubMed, ScienceDirect, Embase, Ovid, and Scopus databases was performed. Pooled contamination rates were determined using random effect models. Subgroup and meta-regression analyses were conducted to identify factors potentially influencing the rates of S aureus and MRSA contamination. Sensitivity and publication bias analyses were performed. Thirty-eight studies were included in the meta-analysis. The pooled contamination rates were 15.0% (95% confidence interval [CI], 9.8%-21.1%) for S aureus and 5.0% (95% CI, 2.7%-7.7%) for MRSA. The subgroup analyses indicated that the pooled rate of S aureus contamination was significantly higher for studies conducted in South America, in developing countries, and during 2010-2015. The pooled rate of MRSA contamination was significantly higher for studies conducted in Africa. The meta-regression analysis suggested that the pooled rate of S aureus contamination was lower for studies conducted in developed countries (odds ratio, 0.664; 95% CI, 0.509-0.867; P = .004). No bias was found in the publication of the rates of S aureus and MRSA contamination. S aureus and MRSA contamination statuses of high-touch items are worrisome and should be paid greater attention. Developing country status was a risk factor for S aureus contamination. Copyright © 2017 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

Dynamics of indigenous bacterial communities associated with crude oil degradation in soil microcosms during nutrient-enhanced bioremediation.

PubMed

Chikere, Chioma B; Surridge, Karen; Okpokwasili, Gideon C; Cloete, Thomas E

2012-03-01

Bacterial population dynamics were examined during bioremediation of an African soil contaminated with Arabian light crude oil and nutrient enrichment (biostimulation). Polymerase chain reaction followed by denaturing gradient gel electrophoresis (DGGE) were used to generate bacterial community fingerprints of the different treatments employing the 16S ribosomal ribonucleic acid (rRNA) gene as molecular marker. The DGGE patterns of the nutrient-amended soils indicated the presence of distinguishable bands corresponding to the oil-contaminated-nutrient-enriched soils, which were not present in the oil-contaminated and pristine control soils. Further characterization of the dominant DGGE bands after excision, reamplification and sequencing revealed that Corynebacterium spp., Dietzia spp., Rhodococcus erythropolis sp., Nocardioides sp., Low G+C (guanine plus cytosine) Gram positive bacterial clones and several uncultured bacterial clones were the dominant bacterial groups after biostimulation. Prominent Corynebacterium sp. IC10 sequence was detected across all nutrient-amended soils but not in oil-contaminated control soil. Total heterotrophic and hydrocarbon utilizing bacterial counts increased significantly in the nutrient-amended soils 2 weeks post contamination whereas oil-contaminated and pristine control soils remained fairly stable throughout the experimental period. Gas chromatographic analysis of residual hydrocarbons in biostimulated soils showed marked attenuation of contaminants starting from the second to the sixth week after contamination whereas no significant reduction in hydrocarbon peaks were seen in the oil-contaminated control soil throughout the 6-week experimental period. Results obtained indicated that nutrient amendment of oil-contaminated soil selected and enriched the bacterial communities mainly of the Actinobacteria phylogenetic group capable of surviving in toxic contamination with concomitant biodegradation of the hydrocarbons. The present study therefore demonstrated that the soil investigated harbours hydrocarbon-degrading bacterial populations which can be biostimulated to achieve effective bioremediation of oil-contaminated soil.

Methodology using a portable X-ray fluorescence device for on-site and rapid evaluation of heavy-atom contamination in wounds: a model study for application to plutonium contamination.

PubMed

Yoshii, Hiroshi; Yanagihara, Kouta; Imaseki, Hitoshi; Hamano, Tsuyoshi; Yamanishi, Hirokuni; Inagaki, Masayo; Sakai, Yasuhiro; Sugiura, Nobuyuki; Kurihara, Osamu; Sakai, Kazuo

2014-01-01

Workers decommissioning the Fukushima-Daiichi nuclear power plant damaged from the Great East Japan Earthquake and resulting tsunami are at risk of injury with possible contamination from radioactive heavy atoms including actinides, such as plutonium. We propose a new methodology for on-site and rapid evaluation of heavy-atom contamination in wounds using a portable X-ray fluorescence (XRF) device. In the present study, stable lead was used as the model contaminant substitute for radioactive heavy atoms. First, the wound model was developed by placing a liquid blood phantom on an epoxy resin wound phantom contaminated with lead. Next, the correlation between the concentration of contaminant and the XRF peak intensity was formulated considering the thickness of blood exiting the wound. Methods to determine the minimum detection limit (MDL) of contaminants at any maximal equivalent dose to the wound by XRF measurement were also established. For example, in this system, at a maximal equivalent dose of 16.5 mSv to the wound and blood thickness of 0.5 mm, the MDL value for lead was 1.2 ppm (3.1 nmol). The radioactivity of 239Pu corresponding to 3.1 nmol is 1.7 kBq, which is lower than the radioactivity of 239Pu contaminating puncture wounds in previous severe accidents. In conclusion, the established methodology could be beneficial for future development of a method to evaluate plutonium contamination in wounds. Highlights: Methodology for evaluation of heavy-atom contamination in a wound was established. A portable X-ray fluorescence device enables on-site, rapid and direct evaluation. This method is expected to be used for evaluation of plutonium contamination in wounds.

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.

Contamination Knowledge Strategy for the Mars 2020 Sample-Collecting Rover

NASA Technical Reports Server (NTRS)

Farley, K. A.; Williford, K.; Beaty, D W.; McSween, H. Y.; Czaja, A. D.; Goreva, Y. S.; Hausrath, E.; Herd, C. D. K.; Humayun, M.; McCubbin, F. M.;

Contaminated Sediment Management in Dam Removals and River Restoration Efforts: Critical Need for Research and Policy Development

NASA Astrophysics Data System (ADS)

Evans, J. E.

2015-12-01

Over 1,000 U.S. dams have been removed (1975-2015) for reasons including obsolescence, liability concerns, water quality upgrades, fisheries, or ecosystem enhancements. Contaminated sediment can significantly complicate the approval process, cost, and timeline of a dam removal, or stop it entirely. In a dam removal, reservoir sediment changes from a sink to a source of contaminants. Recently, the Sierra Club sued to stop the removal of a large dam in Ohio because of the potential impact of phosphate releases on toxic algal blooms in Lake Erie. Heavy metals, PCBs, PAHs, pesticides, and petroleum hydrocarbons can be present in reservoir sediments. In a non-dam removal scenario, reservoir management tools range from "no action" to dredging, dewatering and removal, or sediment capping. But it is not clear how these reservoir management techniques apply to dam removals. Case studies show typically >80% of the reservoir sediment is eventually eroded, precluding sediment capping as a containment option. However, the released contaminants are diluted by mixing with "clean" sediment and are transported to different physio-chemical environments which may immobilize or biodegrade the contaminants. Poorly understood options include phased drawdown/reseeding the former reservoir to contain sediments, diking contaminant "hot spots," and addressing contaminant stratigraphy (where historical use created "hot layers" in the reservoir sediment). Research and policy development needs include: (1) assessment methods based on synergistic effects of multiple contaminants being present; (2) ways to translate the pre-removal contaminant concentrations to post-removal health risks downstream; (3) evaluation of management practices for contaminant "hot spots" and "hot layers;" (4) tools to forecast the presence of contaminated sediment using easily accessible information; and (5) ways to limit liability risk for organizations participating in dam removals involving contaminated sediment.

GROUNDWATER REMEDIATION SOLUTIONS AT HANFORD

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

Gilmore, Tyler J.; Truex, Michael J.; Williams, Mark D.

2007-02-26

In 2006, Congress provided funding to the U. S. Department of Energy (DOE) to study new technologies that could be used to treat contamination from the Hanford Site that might impact the Columbia River. The contaminants of concern are primarily metals and radionuclides, which are byproducts of Hanford’s cold war mission to produce plutonium for atomic weapons. The DOE asked Pacific Northwest National Laboratory (PNNL) to consider this problem and develop approaches to address the contamination that threatens the river. DOE identified three high priority sites that had groundwater contamination migrating towards the Columbia river for remediation. The contaminants includedmore » strontium-90, uranium and chromium. Remediation techniques for metals and radionuclides focus primarily on altering the oxidation state of the contaminant chemically or biologically, isolating the contaminants from the environment through adsorption or encapsulation or concentrating the contaminants for removal. A natural systems approach was taken that uses a mass balance concept to frame the problem and determine the most appropriate remedial approach. This approach provides for a scientifically based remedial decision. The technologies selected to address these contaminants included an apatite adsorption barrier coupled with a phytoremediation to address the strontium-90 contamination, injection of polyphosphate into the subsurface to sequester uranium, and a bioremediation approach to reduce chromium contamination in the groundwater. The ability to provide scientifically based approaches is in large part due to work developed under previous DOE Office of Science and Office of Environmental Management projects. For example, the polyphosphate and the bioremediation techniques, were developed by PNNL under the EMSP and NABIR programs. Contaminated groundwater under the Hanford Site poses a potential risk to humans and the Columbia River. These new technologies holds great promise for effectively remediating the residual waste that threatens the environment.« less

Effects of PCB Substrate Surface Finish, Flux, and Phosphorus Content on Ionic Contamination

NASA Astrophysics Data System (ADS)

Bacior, M.; Sobczak, N.; Siewiorek, A.; Kudyba, A.; Homa, M.; Nowak, R.; Dziula, M.; Masłoń, S.

2015-02-01

The ionic contamination on printed circuit boards (PCB) having different surface finishes was examined using ionograph. The study was performed at the RT on three types of PCBs covered with: (i) hot air solder leveling (HASL LF), (ii) electroless nickel immersion gold (ENIG), and (iii) organic surface protectant (OSP), all on Cu substrates, as well as two types of fluxes, namely EF2202 and RF800. In the group of boards without soldered components, the lowest average value of contamination was for the ENIG 18 µm surface (0.01 μg NaCl/cm2). Boards with soldered components were more contaminated (from 0.29 μg NaCl/cm2 for the HASL LF 18 µm surface). After spraying boards with fluxing agents, the values of contaminants were the highest. The influence of phosphorus content in Ni-P layer of ENIG finish on ionic contamination was examined. In the group of PCBs with Au coating, the smallest amount of surface contaminants (0.32 μg NaCl/cm2) was for Ni-2-5%P layer. PCBs with Ni-11%P layer were higher contaminated (0.47 μg NaCl/cm2), and another with Ni-8%P layer had 0.81 μg NaCl/cm2. PCBs without Au coating, had the lowest contamination (0.48 μg NaCl/cm2) at phosphorous content equal 11%P. Higher contamination (0.67 μg NaCl/cm2) was at 2-5%P, up to 1.98 μg NaCl/cm2 for 8% of P. Boards with Au finish have lower value of contamination than identical boards without Au layer thus contributing to better reliability of electronic assemblies, since its failures due to current leakage and corrosion can be caused by contaminants.

Optimal design of active spreading systems to remediate sorbing groundwater contaminants in situ.

PubMed

Piscopo, Amy N; Neupauer, Roseanna M; Kasprzyk, Joseph R

2016-07-01

The effectiveness of in situ remediation to treat contaminated aquifers is limited by the degree of contact between the injected treatment chemical and the groundwater contaminant. In this study, candidate designs that actively spread the treatment chemical into the contaminant are generated using a multi-objective evolutionary algorithm. Design parameters pertaining to the amount of treatment chemical and the duration and rate of its injection are optimized according to objectives established for the remediation - maximizing contaminant degradation while minimizing energy and material requirements. Because groundwater contaminants have different reaction and sorption properties that influence their ability to be degraded with in situ remediation, optimization was conducted for six different combinations of reaction rate coefficients and sorption rates constants to represent remediation of the common groundwater contaminants, trichloroethene, tetrachloroethene, and toluene, using the treatment chemical, permanganate. Results indicate that active spreading for contaminants with low reaction rate coefficients should be conducted by using greater amounts of treatment chemical mass and longer injection durations relative to contaminants with high reaction rate coefficients. For contaminants with slow sorption or contaminants in heterogeneous aquifers, two different design strategies are acceptable - one that injects high concentrations of treatment chemical mass over a short duration or one that injects lower concentrations of treatment chemical mass over a long duration. Thus, decision-makers can select a strategy according to their preference for material or energy use. Finally, for scenarios with high ambient groundwater velocities, the injection rate used for active spreading should be high enough for the groundwater divide to encompass the entire contaminant plume. Copyright © 2016 Elsevier B.V. All rights reserved.

Early Wound Morbidity after Open Ventral Hernia Repair with Biosynthetic or Polypropylene Mesh.

PubMed

Sahoo, Sambit; Haskins, Ivy N; Huang, Li-Ching; Krpata, David M; Derwin, Kathleen A; Poulose, Benjamin K; Rosen, Michael J

2017-10-01

Recently introduced slow-resorbing biosynthetic and non-resorbing macroporous polypropylene meshes are being used in hernias with clean-contaminated and contaminated wounds. However, information about the use of biosynthetic meshes and their outcomes compared with polypropylene meshes in clean-contaminated and contaminated cases is lacking. Here we evaluate the use of biosynthetic mesh and polypropylene mesh in elective open ventral hernia repair (OVHR) and investigate differences in early wound morbidity after OVHR within clean-contaminated and contaminated cases. All elective, OVHR with biosynthetic mesh or uncoated polypropylene mesh from January 2013 through October 2016 were identified within the Americas Hernia Society Quality Collaborative. Association of mesh type with 30-day wound events in clean-contaminated or contaminated wounds was investigated using a 1:3 propensity-matched analysis. Biosynthetic meshes were used in 8.5% (175 of 2,051) of elective OVHR, with the majority (57.1%) used in low-risk or comorbid clean cases. Propensity-matched analysis in clean-contaminated and contaminated cases showed no significant difference between biosynthetic mesh and polypropylene mesh groups for 30-day surgical site occurrences (20.7% vs 16.7%; p = 0.49) or unplanned readmission (13.8% vs 9.8%; p = 0.4). However, surgical site infections (22.4% vs 10.9%; p = 0.03), surgical site occurrences requiring procedural intervention (24.1% vs 13.2%; p = 0.049), and reoperation rates (13.8% vs 4.0%; p = 0.009) were significantly higher in the biosynthetic group. Biosynthetic mesh appears to have higher rates of 30-day wound morbidity compared with polypropylene mesh in elective OVHR with clean-contaminated or contaminated wounds. Additional post-market analysis is needed to provide evidence defining best mesh choices, location, and surgical technique for repairing contaminated ventral hernias. Copyright © 2017 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

Climate change-contaminant interactions in marine food webs: Toward a conceptual framework.

PubMed

Alava, Juan José; Cheung, William W L; Ross, Peter S; Sumaila, U Rashid

2017-10-01

Climate change is reshaping the way in which contaminants move through the global environment, in large part by changing the chemistry of the oceans and affecting the physiology, health, and feeding ecology of marine biota. Climate change-associated impacts on structure and function of marine food webs, with consequent changes in contaminant transport, fate, and effects, are likely to have significant repercussions to those human populations that rely on fisheries resources for food, recreation, or culture. Published studies on climate change-contaminant interactions with a focus on food web bioaccumulation were systematically reviewed to explore how climate change and ocean acidification may impact contaminant levels in marine food webs. We propose here a conceptual framework to illustrate the impacts of climate change on contaminant accumulation in marine food webs, as well as the downstream consequences for ecosystem goods and services. The potential impacts on social and economic security for coastal communities that depend on fisheries for food are discussed. Climate change-contaminant interactions may alter the bioaccumulation of two priority contaminant classes: the fat-soluble persistent organic pollutants (POPs), such as polychlorinated biphenyls (PCBs), as well as the protein-binding methylmercury (MeHg). These interactions include phenomena deemed to be either climate change dominant (i.e., climate change leads to an increase in contaminant exposure) or contaminant dominant (i.e., contamination leads to an increase in climate change susceptibility). We illustrate the pathways of climate change-contaminant interactions using case studies in the Northeastern Pacific Ocean. The important role of ecological and food web modeling to inform decision-making in managing ecological and human health risks of chemical pollutants contamination under climate change is also highlighted. Finally, we identify the need to develop integrated policies that manage the ecological and socioeconomic risk of greenhouse gases and marine pollutants. © 2017 John Wiley & Sons Ltd.

Reducing Blood Culture Contamination in the Emergency Department: An Interrupted Time Series Quality Improvement Study

PubMed Central

Self, Wesley H.; Speroff, Theodore; Grijalva, Carlos G.; McNaughton, Candace D.; Ashburn, Jacki; Liu, Dandan; Arbogast, Patrick G.; Russ, Stephan; Storrow, Alan B.; Talbot, Thomas R.

2012-01-01

Objectives Blood culture contamination is a common problem in the emergency department (ED) that leads to unnecessary patient morbidity and health care costs. The study objective was to develop and evaluate the effectiveness of a quality improvement (QI) intervention for reducing blood culture contamination in an ED. Methods The authors developed a QI intervention to reduce blood culture contamination in the ED and then evaluated its effectiveness in a prospective interrupted times series study. The QI intervention involved changing the technique of blood culture specimen collection from the traditional clean procedure, to a new sterile procedure, with standardized use of sterile gloves and a new materials kit containing a 2% chlorhexidine skin antisepsis device, a sterile fenestrated drape, a sterile needle, and a procedural checklist. The intervention was implemented in a university-affiliated ED and its effect on blood culture contamination evaluated by comparing the biweekly percentages of blood cultures contaminated during a 48-week baseline period (clean technique), and 48-week intervention period (sterile technique), using segmented regression analysis with adjustment for secular trends and first-order autocorrelation. The goal was to achieve and maintain a contamination rate below 3%. Results During the baseline period, 321 out of 7,389 (4.3%) cultures were contaminated, compared to 111 of 6,590 (1.7%) during the intervention period (p < 0.001). In the segmented regression model, the intervention was associated with an immediate 2.9% (95% CI = 2.2% to 3.2%) absolute reduction in contamination. The contamination rate was maintained below 3% during each biweekly interval throughout the intervention period. Conclusions A QI assessment of ED blood culture contamination led to development of a targeted intervention to convert the process of blood culture collection from a clean to a fully sterile procedure. Implementation of this intervention led to an immediate and sustained reduction of contamination in an ED with a high baseline contamination rate. PMID:23570482

Contamination of stethoscopes and physicians' hands after a physical examination.

PubMed

Longtin, Yves; Schneider, Alexis; Tschopp, Clément; Renzi, Gesuèle; Gayet-Ageron, Angèle; Schrenzel, Jacques; Pittet, Didier

2014-03-01

To compare the contamination level of physicians' hands and stethoscopes and to explore the risk of cross-transmission of microorganisms through the use of stethoscopes. We conducted a structured prospective study between January 1, 2009, and May 31, 2009, involving 83 inpatients at a Swiss university teaching hospital. After a standardized physical examination, 4 regions of the physician's gloved or ungloved dominant hand and 2 sections of the stethoscopes were pressed onto selective and nonselective media; 489 surfaces were sampled. Total aerobic colony counts (ACCs) and total methicillin-resistant Staphylococcus aureus (MRSA) colony-forming unit (CFU) counts were assessed. Median total ACCs (interquartile range) for fingertips, thenar eminence, hypothenar eminence, hand dorsum, stethoscope diaphragm, and tube were 467, 37, 34, 8, 89, and 18, respectively. The contamination level of the diaphragm was lower than the contamination level of the fingertips (P<.001) but higher than the contamination level of the thenar eminence (P=.004). The MRSA contamination level of the diaphragm was higher than the MRSA contamination level of the thenar eminence (7 CFUs/25 cm(2) vs 4 CFUs/25 cm(2); P=.004). The correlation analysis for both total ACCs and MRSA CFU counts revealed that the contamination level of the diaphragm was associated with the contamination level of the fingertips (Spearman's rank correlation coefficient, ρ=0.80; P<.001 and ρ=0.76; P<.001, respectively). Similarly, the contamination level of the stethoscope tube increased with the increase in the contamination level of the fingertips for both total ACCs and MRSA CFU counts (ρ=0.56; P<.001 and ρ=.59; P<.001, respectively). These results suggest that the contamination level of the stethoscope is substantial after a single physical examination and comparable to the contamination of parts of the physician's dominant hand. Copyright © 2014 Mayo Foundation for Medical Education and Research. Published by Elsevier Inc. All rights reserved.

Causes and ecological effects of resuspended contaminated sediments (RCS) in marine environments.

PubMed

Roberts, David A

2012-04-01

Sediments act as a net sink for anthropogenic contaminants in marine ecosystems and contaminated sediments may have a range of toxicological effects on benthic fauna and associated species. When resuspended, however, particulate-bound contaminants may be remobilised into the water column and become bioavailable to an additional assemblage of species. Such resuspension occurs through a range of natural and anthropogenic processes each of which may be thought of as pulsed disturbances resulting in pulsed exposures to contaminants. Thus, it is important to understand not only the toxicological responses of organisms to resuspended contaminated sediments (RCS), but also the frequency, magnitude and duration of sediment disturbance events. Such information is rarely collected together with toxicological data. Rather, the majority of published studies (>50% of the articles captured in this review) have taken the form of fixed-duration laboratory-based exposures with individual species. While this research has clearly demonstrated that resuspension of contaminated sediments can liberate sediment-bound contaminants leading to toxicity and bioaccumulation under controlled conditions, the potential for ecological effects in the field is often unclear. Monitoring studies suggest that recurrent natural disturbances such as tides and waves may cause the majority of contaminant release in many environments. However, various processes also act to limit the spatial and temporal scales across which contaminants are remobilised to the most toxic dissolved state. Various natural and anthropogenic disturbances of contaminated sediments have been linked to both community-level and sub-lethal responses in exposed populations of invertebrates and fish in the field. Together these findings suggest that resuspension of contaminated sediments is a frequently recurring ecological threat in contaminated marine habitats. Further consideration of how marine communities respond to temporally variable exposures to RCS is required, as well as research into the relative importance of various disturbances under field conditions. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

Distribution and transport of sediment-bound metal contaminants in the rio grande de tarcoles, costa rica (Central America)

USGS Publications Warehouse

Fuller, C.C.; Davis, J.A.; Cain, D.J.; Lamothe, P.J.; Fries Fernandez, T.L.G.; Vargas, J.A.; Murillo, M.M.

1990-01-01

A reconnaissance survey of the extent of metal contamination in the Rio Grande de Tarcoles river system of Costa Rica indicated high levels of chromium (Cr) in the fine-grain bed sediments (83 times Cr background or 3000->5000 ??g/g). In the main channel of the river downstream of the San Jose urban area, Cr contamination in sediments was 4-6 times background and remained relatively constant over 50 km to the mouth of the river. Sediment from a mangrove swamp at the river mouth had Cr levels 2-3 times above background. Similar patterns of dilution were observed for lead (Pb) and zinc (Zn) sediment contamination, although the contamination levels were lower. The high affinity of Cr towards particulate phases, probably as Cr(III), allows the use of Cr contamination levels for delineating regions of deposition of fine-grained sediments and dilution of particle associated contaminants during transport and deposition.A reconnaissance survey of the extent of metal contamination in the Rio Grande de Tarcoles river system of Costa Rica indicated high levels of chromium (Cr) in the fine-grain bed sediments (83 times Cr background or 3000->5000 ??g/g). In the main channel of the river downstream of the San Jose urban area, Cr contamination in sediments was 4-6 times background and remained relatively constant over 50 km to the mouth of the river. Sediments from a mangrove swamp at the river mouth had Cr levels 2-3 times above background. Similar patterns of dilution were observed for lead (Pb) and zinc (Zn) sediment contamination, although the contamination levels were lower. The high affinity of Cr towards particulate phases, probably as Cr(III), allows the use of Cr contamination levels for delineating regions of deposition of fine-grained sediments and dilution of particle associated contaminants during transport and deposition.

The Induction of Mental and Contact Contamination

ERIC Educational Resources Information Center

Lee, Michelle; Shafran, Roz; Burgess, Charlotte; Carpenter, Jodi; Millard, Emma; Thorpe, Susan

2013-01-01

Background: Extreme fear of contamination within obsessive compulsive disorder (OCD) is traditionally conceptualised as a physical phenomenon. More recent research has supported the notion of "mental" contamination (MC) in which people feel contaminated in the absence of physical contact. The current research sought to determine whether…

Contaminants | Hydrogen and Fuel Cells | NREL

Science.gov Websites

-Derived Contaminants Overview Materials Methods Data Tool Partners Publications System Contaminants using several screening methods. The materials are from different manufacturers, comprise different Characterization Methods A flowchart graphic that shows the experimental methods used in the system contaminants

40 CFR 141.55 - Maximum contaminant level goals for radionuclides.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Maximum contaminant level goals for... PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Maximum Contaminant Level Goals and Maximum Residual Disinfectant Level Goals § 141.55 Maximum contaminant level goals for radionuclides...

40 CFR 141.55 - Maximum contaminant level goals for radionuclides.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 23 2011-07-01 2011-07-01 false Maximum contaminant level goals for... PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Maximum Contaminant Level Goals and Maximum Residual Disinfectant Level Goals § 141.55 Maximum contaminant level goals for radionuclides...

Innovative Capping Technology To Prevent The Migration of Toxic Chemicals From Contaminated Sediments

EPA Science Inventory

Capping is a common strategy for decreasing the risk associated with contaminated sediments in lakes and streams. Historically, caps have been designed to physically isolate contaminated sediments and prevent the transport of contaminants from sediments into the water above them...

49 CFR 175.705 - Radioactive contamination.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Radioactive contamination. 175.705 Section 175.705... Regulations Applicable According to Classification of Material § 175.705 Radioactive contamination. (a) A... (radioactive) materials that may have been released from their packagings. (b) When contamination is present or...

41 CFR 109-42.1102-51 - Suspect personal property.

Code of Federal Regulations, 2010 CFR

2010-07-01

... radioactive or chemical contamination may occur shall be considered suspect and shall be monitored using... the level of contamination of excess or surplus personal property to the lowest practicable level. Contaminated personal property that exceeds applicable contamination standards shall not be utilized or...

Corona-discharge air-purification system

NASA Technical Reports Server (NTRS)

Wydeven, T. J.; Flamm, D. L.

1979-01-01

Plasma reaction chamber removes trace contaminants from spacecraft, submarines, and other closed environments by oxidizing contaminants to produce carbon dioxide and water. Contaminants are alcohols, esters, hydrogen sulfide, and ammonia. Others are lubricant solvents such as Freons, aromatics, and Ketones. Contaminants are removed from chamber by scrubber.

40 CFR 445.2 - General definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

...) Contaminated storm water means storm water which comes in direct contact with landfill wastes, the waste... specific areas of a landfill that may produce contaminated storm water include (but are not limited to... sanitary wastewater, non-contaminated storm water, contaminated ground water, and wastewater from recovery...

40 CFR 445.2 - General definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

...) Contaminated storm water means storm water which comes in direct contact with landfill wastes, the waste... specific areas of a landfill that may produce contaminated storm water include (but are not limited to... sanitary wastewater, non-contaminated storm water, contaminated ground water, and wastewater from recovery...

40 CFR 445.2 - General definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

...) Contaminated storm water means storm water which comes in direct contact with landfill wastes, the waste... specific areas of a landfill that may produce contaminated storm water include (but are not limited to... sanitary wastewater, non-contaminated storm water, contaminated ground water, and wastewater from recovery...

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...

Using stable isotopes to estimate habitat-based risk of contaminant exposure in fish

EPA Science Inventory

Sediment contamination is a common threat to sustainability in coastal ecosystems. For fish, the risk of exposure to contaminants will vary with respect to life history, including movements between contaminated inshore and less impacted offshore areas, trophic level, and habitat ...

Overcoming bacterial contamination of fuel ethanol fermentations -- alterntives to antibiotics

USDA-ARS?s Scientific Manuscript database

Fuel ethanol fermentations are not performed under aseptic conditions and microbial contamination reduces yields and can lead to costly "stuck fermentations". Antibiotics are commonly used to combat contaminants, but these may persist in the distillers grains co-product. Among contaminants, it is kn...

Review of mobile communication devices as potential reservoirs of nosocomial pathogens.

PubMed

Brady, R R W; Verran, J; Damani, N N; Gibb, A P

2009-04-01

Innovation in mobile communication technology has provided novel approaches to the delivery of healthcare and improvements in the speed and quality of routine medical communication. Bacterial contamination of mobile communication devices (MCDs) could be an important issue affecting the implementation of effective infection control measures and might have an impact on efforts to reduce cross-contamination. This review examines recent studies reporting bacterial contamination of MCDs, most demonstrating that 9-25% of MCDs are contaminated with pathogenic bacteria. We examine previously investigated risk factors for MCD contamination in addition to work on surface decontamination of the device. Recommendations to reduce contamination risks include staff education, strict hand hygiene measures, guidelines on device cleaning and consideration of the restrictions regarding use of mobile phone technology in certain high risk areas, for example, operating theatres, intensive care units and burns units. Further work is required to evaluate the benefit of such interventions on MCD contamination and to determine whether a link exists between contamination and subsequent patient infection.

Scatter from optical components; Proceedings of the Meeting, San Diego, CA, Aug. 8-10, 1989

NASA Astrophysics Data System (ADS)

Stover, John C.

Various papers on scatter from optical components are presented. Individual topics addressed include: BRDF of SiC and Al foam compared to black paint at 3.39 microns, characterization of optical baffle materials, bidirectional transmittance distribution function of several IR materials at 3.39 microns, thermal cycling effects on the BRDF of beryllium mirrors, BTDV of ZnSe with multilayer coatings at 3.39 microns, scattering from contaminated surfaces, cleanliness correlation by BRDF and PFO instruments, contamination effects on optical surfaces, means of eliminating the effects of particulate contamination on scatter measurements of superfine optical surfaces, vacuum BRDF measurement of cryogenic optical surfaces, Monte Carlo simulation of contaminant transport to and deposition on complex spacecraft surfaces, surface particle observation and BRDF predictions, satellite material contaminant optical properties, dark field photographic techniques for documenting optical surface contamination, design of a laboratory study of contaminant film darkening in space, contamination monitoring approaches for EUV space optics.

Predictive Validity of Explicit and Implicit Threat Overestimation in Contamination Fear

PubMed Central

Green, Jennifer S.; Teachman, Bethany A.

2012-01-01

We examined the predictive validity of explicit and implicit measures of threat overestimation in relation to contamination-fear outcomes using structural equation modeling. Undergraduate students high in contamination fear (N = 56) completed explicit measures of contamination threat likelihood and severity, as well as looming vulnerability cognitions, in addition to an implicit measure of danger associations with potential contaminants. Participants also completed measures of contamination-fear symptoms, as well as subjective distress and avoidance during a behavioral avoidance task, and state looming vulnerability cognitions during an exposure task. The latent explicit (but not implicit) threat overestimation variable was a significant and unique predictor of contamination fear symptoms and self-reported affective and cognitive facets of contamination fear. On the contrary, the implicit (but not explicit) latent measure predicted behavioral avoidance (at the level of a trend). Results are discussed in terms of differential predictive validity of implicit versus explicit markers of threat processing and multiple fear response systems. PMID:24073390

Histopathology of the fish Corydoras paleatus contaminated with sublethal levels of organophosphorus in water and food.

PubMed

Fanta, Edith; Rios, Flávia Sant'Anna; Romão, Silvia; Vianna, Ana Cristina Casagrande; Freiberger, Sandra

2003-02-01

The effects of contamination, through water or food, of a sublethal dose of the organophosphate methyl parathion were analyzed in tissues that are responsible for absorption (gills, intestine) and metabolism (liver), in the freshwater fish Corydoras paleatus. In gill respiratory lamellae, epithelial hyperplasia, edema, and detachment occurred, diminishing sooner after contamination by food than after contamination through water. In the intestine, lipoid vacuolization of enterocytes, apical cytoplasm, and an increase in goblet cell activity occurred mainly after ingestion of contaminated food. The liver exhibited cloudy swelling, bile stagnation, focal necrosis, atrophy, and vacuolization after contamination through both absorption routes, the highest degeneration being between T(8) and T(24). Metabolic processes that depend on liver function were equally impaired by the two routes of contamination, but secondary effects vary with gill and intestine pathologies as a consequence of water and food contamination, respectively. Therefore, a "safe" sublethal dose of methyl parathion causes serious health problems in C. paleatus.

Assessment of contamination and misclassification biases in a randomized controlled trial of a social network peer education intervention to reduce HIV risk behaviors among drug users and risk partners in Philadelphia, PA and Chiang Mai, Thailand.

PubMed

Simmons, Nicole; Donnell, Deborah; Ou, San-San; Celentano, David D; Aramrattana, Apinun; Davis-Vogel, Annet; Metzger, David; Latkin, Carl

2015-10-01

Controlled trials of HIV prevention and care interventions are susceptible to contamination. In a randomized controlled trial of a social network peer education intervention among people who inject drugs and their risk partners in Philadelphia, PA and Chiang Mai, Thailand, we tested a contamination measure based on recall of intervention terms. We assessed the recall of test, negative and positive control terms among intervention and control arm participants and compared the relative odds of recall of test versus negative control terms between study arms. The contamination measures showed good discriminant ability among participants in Chiang Mai. In Philadelphia there was no evidence of contamination and little evidence of diffusion. In Chiang Mai there was strong evidence of diffusion and contamination. Network structure and peer education in Chiang Mai likely led to contamination. Recall of intervention materials can be a useful method to detect contamination in experimental interventions.

Method and system for gas flow mitigation of molecular contamination of optics

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

Delgado, Gildardo; Johnson, Terry; Arienti, Marco

A computer-implemented method for determining an optimized purge gas flow in a semi-conductor inspection metrology or lithography apparatus, comprising receiving a permissible contaminant mole fraction, a contaminant outgassing flow rate associated with a contaminant, a contaminant mass diffusivity, an outgassing surface length, a pressure, a temperature, a channel height, and a molecular weight of a purge gas, calculating a flow factor based on the permissible contaminant mole fraction, the contaminant outgassing flow rate, the channel height, and the outgassing surface length, comparing the flow factor to a predefined maximum flow factor value, calculating a minimum purge gas velocity and amore » purge gas mass flow rate from the flow factor, the contaminant mass diffusivity, the pressure, the temperature, and the molecular weight of the purge gas, and introducing the purge gas into the semi-conductor inspection metrology or lithography apparatus with the minimum purge gas velocity and the purge gas flow rate.« less

Radioactive contamination incidents involving protective clothing

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

Reichelt, R.A.; Clay, M.E.; Eichorst, A.J.

1998-01-01

The study focuses on incidents at Department of Energy facilities involving the migration of radioactive contaminants through protective clothing. The authors analyzed 68 occurrence reports for the following factors: (1) type of work, (2) working conditions, (3) type of anti-contamination material; (4) area of body or clothing contaminated; and (5) nature of spread of contamination. A majority of reports identified strenuous work activities such as maintenance, construction, or decontamination and decommissioning projects. The reports also indicated adverse working conditions that included hot and humid or cramped work environments. The type of anti-contamination clothing most often identified was cotton or water-resistantmore » disposable clothing. Most of the reports also indicated contaminants migrating through perspiration-soaked areas, typically in the knees and forearms. On the basis of their survey, the authors recommend the use of improved engineering controls and resilient, breathable, waterproof protective clothing for work in hot, humid, or damp areas where the possibility of prolonged contact with contamination cannot be easily avoided or controlled. 1 ref., 6 figs., 1 tab.« less

Corrective Action Investigation Plan for Corrective Action Unit 568: Area 3 Plutonium Dispersion Sites Nevada National Security Site, Nevada, Revision 0

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

Matthews, Patrick

2014-01-01

CAU 568 is a grouping of sites where there has been a suspected release of contamination associated with nuclear testing. This document describes the planned investigation of CAU 568, which comprises the following corrective action sites (CASs): • 03-23-17, S-3I Contamination Area • 03-23-19, T-3U Contamination Area • 03-23-20, Otero Contamination Area • 03-23-22, Platypus Contamination Area • 03-23-23, San Juan Contamination Area • 03-23-26, Shrew/Wolverine Contamination Area These sites are being investigated because existing information on the nature and extent of potential contamination is insufficient to evaluate and recommend corrective action alternatives (CAAs). Additional information will be obtained bymore » conducting a corrective action investigation before evaluating CAAs and selecting the appropriate corrective action for each CAS. The results of the field investigation will support a defensible evaluation of viable CAAs that will be presented in the investigation report.« less

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.

Prevention of Salmonella cross-contamination in an oilmeal manufacturing plant.

PubMed

Morita, T; Kitazawa, H; Iida, T; Kamata, S

2006-08-01

The mechanisms of Salmonella contamination in an oilmeal plant were investigated and the basic data were collected in order to achieve control of Salmonella in oilmeal. Salmonella was detected in all contamination vectors and environmental factors investigated, namely: operators, processing floor, dust in the air and rodents. In particular, high concentrations of Salmonella were detected on the processing floor of the manufacturing area, which has high oil content. Steam was the most effective disinfection method used for the processing floor, as the effects of heat sterilization and disinfection may work in tandem. In addition, restricting the movement of operators of the production chain remarkably reduced Salmonella contamination, even in areas of otherwise high contamination. Within the oilmeal plant, high Salmonella contamination rates for the processing floor represent the greatest risk of contamination of oilmeal via operators, dust in the air and rodents. Therefore, control of the processing floor is the most important means for reducing the oilmeal contamination rate. Specific Salmonella control methods for oilmeal plants have been established.

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

Reduction of High Levels of Internal Radio-Contamination by Dietary Intervention in Residents of Areas Affected by the Fukushima Daiichi Nuclear Plant Disaster: A Case Series

PubMed Central

Tsubokura, Masaharu; Kato, Shigeaki; Nomura, Shuhei; Gilmour, Stuart; Nihei, Masahiko; Sakuma, Yu; Oikawa, Tomoyoshi; Kanazawa, Yukio; Kami, Masahiro; Hayano, Ryugo

2014-01-01

Maintaining low levels of chronic internal contamination among residents in radiation-contaminated areas after a nuclear disaster is a great public health concern. However, the efficacy of reduction measures for individual internal contamination remains unknown. To reduce high levels of internal radiation exposure in a group of individuals exposed through environmental sources, we performed careful dietary intervention with identification of suspected contaminated foods, as part of mass voluntary radiation contamination screenings and counseling program in Minamisoma Municipal General Hospital and Hirata Central Hospital. From a total of 30,622 study participants, only 9 residents displayed internal cesium-137 (Cs-137) levels of more than 50 Bq/kg. The median level of internal Cs-137 contamination in these residents at the initial screening was 4,830 Bq/body (range: 2,130–15,918 Bq/body) and 69.6 Bq/kg (range: 50.7–216.3 Bq/kg). All these residents with high levels of internal contamination consumed homegrown produce without radiation inspection, and often collected mushrooms in the wild or cultivated them on bed-logs in their homes. They were advised to consume distributed food mainly and to refrain from consuming potentially contaminated foods without radiation inspection and local produces under shipment restrictions such as mushrooms, mountain vegetables, and meat of wild life. A few months after the intervention, re-examination of Cs levels revealed remarkable reduction of internal contamination in all residents. Although the levels of internal radiation exposure appear to be minimal amongst most residents in Fukushima, a subset of the population, who unknowingly consumed highly contaminated foodstuffs, experienced high levels of internal contamination. There seem to be similarities in dietary preferences amongst residents with high internal contamination levels, and intervention based on pre- and post-test counseling and dietary advice from medical care providers about risky food intake appears to be a feasible option for changing residents' dietary practices, subsequently resulting in a reduction in Cs internal contamination levels. PMID:24932486

Flight evaluation of an insect contamination protection system for laminar flow wings

NASA Technical Reports Server (NTRS)

Croom, C. C.; Holmes, B. J.

1985-01-01

The maintenance of minimum wing leading edge contamination is critical to the preservation of drag-reducing laminar flow; previous methods for the prevention of leading edge contamination by insects have, however, been rendered impractical by their excessive weight, cost, or inconvenience. Attention is presently given to the results of a NASA flight experiment which evaluated the performance of a porous leading edge fluid-discharge ice protection system in the novel role of insect contamination removal; high insect contamination conditions were also noted in the experiment. Very small amounts of the fluid are found to be sufficient for insect contamination protection.

Skylab program payload integration. TO27 sample array

NASA Technical Reports Server (NTRS)

Muscari, J. A.; Westcott, P. A.

1974-01-01

The objective of the TO27 sample array was to determine the change in optical properties of various transmissive windows, mirrors, and diffraction gratings caused by the deposition of contaminants found about the orbital assembly. The expected information to be obtained from the total TO27 sample array program is as follows: (1) effect of space contaminants on transmittance, reflectance, grating efficiency, and polarization; (2) variations in deposition of contaminants due to substrate, solar radiation, period of exposure, direction of exposure, and geometry effects; (3) identification of contaminants and source of evolution; (4) time of contaminant evolution and lingering time; and (5) guidelines for a model of spacecraft contamination.

[Quantitative detection on contamination of Listeria monocytogenes isolated from retail ready-to-eat meats in Beijing].

PubMed

Wang, Wei; Yan, Shaofei; Bai, Li; Li, Zhigang; Du, Chunming; Li, Fengqin

2015-11-01

To survey the contamination of L. monocytogenes isolated from retail ready-to-eat meats in Beijing. Ready-to-eat meats were quantitatively detected for L. monocytogenes using MPN method. L. monocytogenes isolates were analyzed by PFGE. Fourteen out of 197 ready-to-eat meat samples were positive for L. monocytogenes with the contamination rate of 7.11% and the geometry mean contamination level of 14.31 MPN/g. The contamination of L. monocytogenes isolated from free trade market (13.89%) was more severe than those from specificity store (8.57%), supermarket (5.75%) and restaurant (2.56%), while supermarket had the highest mean contamination level of 22.78 MPN/g. A total of 13 PFGE types were characterized using DICE-UPGMA analysis through BioNumerics 7.1 software. There were two isolates from the same free trade market share the same PFGE type, which suggested the same contamination source of both samples. Contamination of L. monocytogenes exist in retail ready-to-eat meats. The contamination level of L. monocytogenes isolated from free trade market is more severe than those from specificity store, supermarket and restaurant.

Phytoremediation removal rates of benzene, toluene, and chlorobenzene.

PubMed

Limmer, Matt A; Wilson, Jordan; Westenberg, David; Lee, Amy; Siegman, Mark; Burken, Joel G

2018-06-07

Phytoremediation is a sustainable remedial approach, although performance efficacy is rarely reported. In this study, we assessed a phytoremediation plot treating benzene, toluene, and chlorobenzene. A comparison of the calculated phytoremediation removal rate with estimates of onsite contaminant mass was used to forecast cleanup periods. The investigation demonstrated that substantial microbial degradation was occurring in the subsurface. Estimates of transpiration indicated that the trees planted were removing approximately 240,000 L of water per year. This large quantity of water removal implies substantial removal of contaminant due to large amounts of contaminants in the groundwater; however, these contaminants extensively sorb to the soil, resulting in large quantities of contaminant mass in the subsurface. The total estimate of subsurface contaminant mass was also complicated by the presence of non-aqueous phase liquids (NAPL), additional contaminant masses that were difficult to quantify. These uncertainties of initial contaminant mass at the site result in large uncertainty in the cleanup period, although mean estimates are on the order of decades. Collectively, the model indicates contaminant removal rates on the order of 10 -2 -10 0 kg/tree/year. The benefit of the phytoremediation system is relatively sustainable cleanup over the long periods necessary due to the presence of NAPL.

Potential microbial contamination during sampling of permafrost soil assessed by tracers

NASA Astrophysics Data System (ADS)

Bang-Andreasen, Toke; Schostag, Morten; Priemé, Anders; Elberling, Bo; Jacobsen, Carsten S.

2017-02-01

Drilling and handling of permanently frozen soil cores without microbial contamination is of concern because contamination e.g. from the active layer above may lead to incorrect interpretation of results in experiments investigating potential and actual microbial activity in these low microbial biomass environments. Here, we present an example of how microbial contamination from active layer soil affected analysis of the potentially active microbial community in permafrost soil. We also present the development and use of two tracers: (1) fluorescent plastic microspheres and (2) Pseudomonas putida genetically tagged with Green Fluorescent Protein production to mimic potential microbial contamination of two permafrost cores. A protocol with special emphasis on avoiding microbial contamination was developed and employed to examine how far microbial contamination can penetrate into permafrost cores. The quantity of tracer elements decreased with depth into the permafrost cores, but the tracers were detected as far as 17 mm from the surface of the cores. The results emphasize that caution should be taken to avoid microbial contamination of permafrost cores and that the application of tracers represents a useful tool to assess penetration of potential microbial contamination into permafrost cores.

Environmental microbial contamination in a stem cell bank.

PubMed

Cobo, F; Concha, A

2007-04-01

The aim of this study was to evaluate the main environmental microbial contaminants of the clean rooms in our stem cell bank. We have measured the microbial air contamination by both passive and active air sampling and the microbial monitoring of surfaces by means of Rodac plates. The environmental monitoring tests were carried out in accordance with the guidelines of European Pharmacopeia and US Pharmacopeia. The micro-organisms were identified by means of an automated system (VITEK 2). During the monitoring, the clean rooms are continually under good manufacturing practices specifications. The most frequent contaminants were Gram-positive cocci. The main contaminants in our stem cell bank were coagulase-negative staphylococci and other opportunistic human pathogens. In order to assure the levels of potential contamination in both embryonic and adult stem cell lines, a continuous sampling of air particles and testing for viable microbiological contamination is necessary. This study is the first evaluation of the environmental contaminants in stem cell banks and can serve as initial evaluation for these establishments. The introduction of environmental monitoring programmes in the processing of stem cell lines could diminish the risk of contamination in stem cell cultures.

Unwanted sexual experiences and cognitive appraisals that evoke mental contamination.

PubMed

Ishikawa, Ryotaro; Kobori, Osamu; Shimizu, Eiji

2015-01-01

Mental contamination is a psychological sense of contamination that involves an internal, emotional feeling of dirtiness that may be evoked by unwanted thoughts and images, such as sexual assaults. This study aimed to investigate which types of unwanted sexual experiences evoke the strongest mental contamination, and to test the hypothesis that cognitive appraisals of an unwanted sexual experience predict indices of mental contamination (i.e. feeling of dirtiness, urge to wash, internal negative emotions, and external negative emotions). 148 female participants were asked to recall their most distressing unwanted sexual experiences. Indices of mental contamination and cognitive appraisals of the experience were then assessed. Our findings indicated that individuals recalling experiences related to rape felt more intense feelings of dirtiness than individuals recalling other types of unwanted sexual experience, such as verbal sexual assault, visual sexual assault, and forcible touching/frottage. In addition, hierarchical regression analyses demonstrated that a cognitive appraisal of perceived violation predicted all of the indices of mental contamination after controlling anxiety, depression, and fear of contact contamination. The present study demonstrated that an individual is at greatest risk of mental contamination if she has experienced rape/attempted rape, and if she makes a cognitive appraisal of violation regarding the incident.

Health assessment for Neal's Dump, Spencer, Owen County, Indiana, Region 5. CERCLIS No. IND980794549. Preliminary report

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

Not Available

Neal's Dump (the site) is located four miles south of Spencer, Indiana, on Pottersville Road. The site is 1/2 acre in size and 20 feet deep. Neal's Dump served as a waste disposal site from approximately 1958 to the early seventies. The Westinghouse Electric Corporation, Bloomington, Indiana, disposed of an unknown amount of capacitors, rage, and sawdust contaminated with polychlorinated biphenyls (PCBs). The contaminated soil on-site has been found to contain very high levels of PCBs. In November 1980, the Environmental Protection Agency (EPA) collected soil samples at Neal's Dump. Results indicated a high concentration of PCBs. Several other organicmore » contaminants have been found on-site. There are several environmental pathways of concern. The migration of PCBs off-site via contaminated groundwater potentially contaminate private residential wells. Also of concern is potential surface water contamination. Additional pathways include contamination of fish and other wildlife from surface water run-off or direct contact with contaminated sediments and soils and wind-driven contaminated soil. This site is of public health concern because a risk to human health exists from exposure to hazardous substances at concentrations that may result in adverse human health effects.« less

Joint Estimation of Contamination, Error and Demography for Nuclear DNA from Ancient Humans

PubMed Central

Slatkin, Montgomery

2016-01-01

When sequencing an ancient DNA sample from a hominin fossil, DNA from present-day humans involved in excavation and extraction will be sequenced along with the endogenous material. This type of contamination is problematic for downstream analyses as it will introduce a bias towards the population of the contaminating individual(s). Quantifying the extent of contamination is a crucial step as it allows researchers to account for possible biases that may arise in downstream genetic analyses. Here, we present an MCMC algorithm to co-estimate the contamination rate, sequencing error rate and demographic parameters—including drift times and admixture rates—for an ancient nuclear genome obtained from human remains, when the putative contaminating DNA comes from present-day humans. We assume we have a large panel representing the putative contaminant population (e.g. European, East Asian or African). The method is implemented in a C++ program called ‘Demographic Inference with Contamination and Error’ (DICE). We applied it to simulations and genome data from ancient Neanderthals and modern humans. With reasonable levels of genome sequence coverage (>3X), we find we can recover accurate estimates of all these parameters, even when the contamination rate is as high as 50%. PMID:27049965

Potential microbial contamination during sampling of permafrost soil assessed by tracers.

PubMed

Bang-Andreasen, Toke; Schostag, Morten; Priemé, Anders; Elberling, Bo; Jacobsen, Carsten S

2017-02-23

Drilling and handling of permanently frozen soil cores without microbial contamination is of concern because contamination e.g. from the active layer above may lead to incorrect interpretation of results in experiments investigating potential and actual microbial activity in these low microbial biomass environments. Here, we present an example of how microbial contamination from active layer soil affected analysis of the potentially active microbial community in permafrost soil. We also present the development and use of two tracers: (1) fluorescent plastic microspheres and (2) Pseudomonas putida genetically tagged with Green Fluorescent Protein production to mimic potential microbial contamination of two permafrost cores. A protocol with special emphasis on avoiding microbial contamination was developed and employed to examine how far microbial contamination can penetrate into permafrost cores. The quantity of tracer elements decreased with depth into the permafrost cores, but the tracers were detected as far as 17 mm from the surface of the cores. The results emphasize that caution should be taken to avoid microbial contamination of permafrost cores and that the application of tracers represents a useful tool to assess penetration of potential microbial contamination into permafrost cores.

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.

[Legionella spp. contamination in indoor air: preliminary results of an Italian multicenter study].

PubMed

Montagna, Maria Teresa; De Giglio, Osvalda; Napoli, Christian; Cannova, Lucia; Cristina, Maria Luisa; Deriu, Maria Grazia; Delia, Santi Antonino; Giuliano, Ada; Guida, Marco; Laganà, Pasqualina; Liguori, Giorgio; Mura, Ida; Pennino, Francesca; Rossini, Angelo; Tardivo, Stefano; Torre, Ida; Torregrossa, Maria Valeria; Villafrate, Maria Rosaria; Albertini, Roberto; Pasquarella, Cesira

2014-01-01

To propose a standardized protocol for the evaluation of Legionella contamination in air. A bathroom having a Legionella contamination in water >1,000 cfu/l was selected in 10 different healthcare facilities. Air contamination was assessed by active (Surface Air System, SAS) and passive (Index of Microbial Air, IMA) sampling for 8 hours, about 1 m away from the floor and 50 cm from the tap water. Two hundred liters of air were sampled by SAS every 12 min, after flushing water for 2 min. The IMA value was calculated as the mean value of colony forming units/16 plates exposed during sampling (2 plates/hour). Water contamination was evaluated at T0, after 4 and 8 hours, according to the standard methods. Air contamination by Legionella was found in three healthcare facilities (one with active and two with passive sampling), showing a concomitant tap water contamination (median=40,000; range 1,100-43,000 cfu/l). The remaining seven hospitals isolated Legionella spp. exclusively from water samples (median=8,000; range 1,200-70,000 cfu/l). Our data suggest that environmental Legionella contamination cannot be assessed only through the air sampling, even in the presence of an important water 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.

Baseline risk assessment of ground water contamination at the uranium mill tailings site near Durango, Colorado

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

Not Available

1995-02-01

This risk assessment evaluates the possibility of health and environmental risks from contaminated ground water at the uranium mill tailings site near Durango, Colorado. The former uranium processing site`s contaminated soil and material were removed and placed at a disposal site located in Body Canyon, Colorado, during 1986--1991 by the US Departments of Energy`s Uranium Mill Tailings Remedial Action (UMTRA) Project. Currently, the UMTRA Project is evaluating the nature and extent of ground water contamination at the site. This risk assessment follows an approach similar to that used by the US Environmental Protection Agency. The first step is to determinemore » what site-related contaminants are found in ground water samples. The next step in the risk assessment is to determine how much of these contaminants people might ingest if they got their drinking water from a well on the site. In accordance with standard practice for this type of risk assessment, the highest contaminant concentrations from the most contaminated wells are used. The risk assessment then explains the possible health problems that could result from this amount of contamination.« less

HANDBOOK ON ADVANCED PHOTOCHEMICAL OXIDATION ...

EPA Pesticide Factsheets

This handbook summarizes commercial-scale system performance and cost data for advanced photochemical oxidation (APO) treatment of contaminated water, air, and solids. Similar information from pilot- and bench-scale evaluations of APO processes is also included to supplement the commercial-scale data. Performance and cost data is summarized for various APO processes, including vacuum ultraviolet (VUV) photolysis, ultraviolet (UV)/oxidation, photo-Fenton, and dye- or semiconductor-sensitized APO processes. This handbook is intended to assist engineering practitioners in evaluating the applicability of APO processes and in selecting one or more such processes for site-specific evaluation.APO has been shown to be effective in treating contaminated water and air. Regarding contaminated water treatment, UV/oxidation has been evaluated for the most contaminants, while VUV photolysis has been evaluated for the fewest. Regarding contaminated air treatment, the sensitized APO processes have been evaluated for the most contaminants, while VUV photolysis has been evaluated for the fewest.APO processes for treating contaminated solids generally involve treatment of contaminated slurry or leachate generated using an extraction process such as soil washing. APO has been shown to be effective in treating contaminated solids, primarily at the bench-scale level. Information

Emerging contaminants: Presentations at the 2009 Toxicology and Risk Assessment Conference

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

Murnyak, George, E-mail: George.murnyak@us.army.mil; Vandenberg, John, E-mail: Vandenberg.John@epamail.epa.gov; Yaroschak, Paul J., E-mail: Paul.Yaroschak@osd.mil

2011-07-15

A session entitled 'Emerging Contaminants' was held in April 2009 in Cincinnati, OH at the 2009 Toxicology and Risk Assessment Conference. The purpose of the session was to share information on both programmatic and technical aspects associated with emerging contaminants. Emerging contaminants are chemicals or materials that are characterized by a perceived or real threat to human health or environment, a lack of published health standards or an evolving standard. A contaminant may also be 'emerging' because of the discovery of a new source, a new pathway to humans, or a new detection method or technology. The session included fivemore » speakers representing the Department of Defense (DoD), the Environmental Protection Agency (EPA), and each of the military services. The DoD created the Emerging Contaminant Directorate to proactively address environmental, health, and safety concerns associated with emerging contaminants. This session described the scan-watch-action list process, impact assessment methodology, and integrated risk management concept that DoD has implemented to manage emerging contaminants. EPA presented emerging trends in health risk assessment. Researchers made technical presentations on the status of some emerging contaminates in the assessment process (i.e. manganese, RDX, and naphthalene).« less

Biaccumulation and tolerance of heavy metals on the tropical earthworm, Allobophora sp. after exposed to contaminated soil from oil mine waste

NASA Astrophysics Data System (ADS)

Suhendrayatna; Darusman; Raihannah; Nurmala, D.

2018-04-01

In this study, the impact of contaminated soil from oil mine waste on survival, behavior, tolerance, and bioaccumulation of heavy metals by the tropical earthworm, Allobophora sp. has been quantified. Earthworm was isolated from heavy metals-contaminated soil, cultured in laboratory condition, and exposed to contaminated soil from oil mine waste for a couple of months. The behavior and response of earthworms to contaminated soil was monitored for 28 days and evaluated by the response criteria was expressed in scale index (SI) referred to Langdon method. Resistance test of the earthworm (LC50) to heavy metals also conducted with variation soil concentrations of 100%, 50%, 25%, 12.5%, and 6.25%, and 0% (Control). Results showed that contaminated soil extremely affected to the earthworm live, especially length and their body weight. The Lethal Concentration 50% (LC50) of earthworm against contaminated soil was 19.05% (w/w). When exposed to contaminated soil, earthworm accumulated chromium, barium, and manganese at the concentration of 88; 92.2; and 280 mg/kg-DW, respectively. Based on these results, earthworm Allobophora sp. has potential to reduce heavy metals from contaminated soil in the field of bioremediation process.

Potential microbial contamination during sampling of permafrost soil assessed by tracers

PubMed Central

Bang-Andreasen, Toke; Schostag, Morten; Priemé, Anders; Elberling, Bo; Jacobsen, Carsten S.

2017-01-01

Drilling and handling of permanently frozen soil cores without microbial contamination is of concern because contamination e.g. from the active layer above may lead to incorrect interpretation of results in experiments investigating potential and actual microbial activity in these low microbial biomass environments. Here, we present an example of how microbial contamination from active layer soil affected analysis of the potentially active microbial community in permafrost soil. We also present the development and use of two tracers: (1) fluorescent plastic microspheres and (2) Pseudomonas putida genetically tagged with Green Fluorescent Protein production to mimic potential microbial contamination of two permafrost cores. A protocol with special emphasis on avoiding microbial contamination was developed and employed to examine how far microbial contamination can penetrate into permafrost cores. The quantity of tracer elements decreased with depth into the permafrost cores, but the tracers were detected as far as 17 mm from the surface of the cores. The results emphasize that caution should be taken to avoid microbial contamination of permafrost cores and that the application of tracers represents a useful tool to assess penetration of potential microbial contamination into permafrost cores. PMID:28230151

Phytoremediation of fuel oil and lead co-contaminated soil by Chromolaena odorata in association with Micrococcus luteus.

PubMed

Jampasri, Kongkeat; Pokethitiyook, Prayad; Kruatrachue, Maleeya; Ounjai, Puey; Kumsopa, Acharaporn

2016-10-02

Phytoremediation is widely promoted as a cost-effective technology for treating heavy metal and total petroleum hydrocarbon (TPH) co-contaminated soil. This study investigated the concurrent removal of TPHs and Pb in co-contaminated soil (27,000 mg kg(-1) TPHs, 780 mg kg(-1) Pb) by growing Siam weed (Chromolaena odorata) in a pot experiment for 90 days. There were four treatments: co-contaminated soil; co-contaminated soil with C. odorata only; co-contaminated soil with C. odorata and Micrococcus luteus inoculum; and co-contaminated soil with M. luteus only. C. odorata survived and grew well in the co-contaminated soil. C. odorata with M. luteus showed the highest Pb accumulation (513.7 mg kg(-1)) and uptake (7.7 mg plant(-1)), and the highest reduction percentage of TPHs (52.2%). The higher TPH degradation in vegetated soils indicated the interaction between the rhizosphere microorganisms and plants. The results suggested that C. odorata together with M. luteus and other rhizosphere microorganisms is a promising candidate for the removal of Pb and TPHs in co-contaminated soils.

Toxicity of lead-contaminated sediment to mallards

USGS Publications Warehouse

Heinz, G.H.; Hoffman, D.J.; Sileo, L.; Audet, D.J.; LeCaptain, L.J.

1999-01-01

Because consumption of lead-contaminated sediment has been suspected as the cause of waterfowl mortality in the Coeur d?Alene River basin in Idaho, we studied the bioavailability and toxicity of this sediment to mallards (Anas platyrhynchos). In experiment 1, one of 10 adult male mallards died when fed a pelleted commercial duck diet that contained 24% lead-contaminated sediment (with 3,400 μg/g lead in the sediment). Protoporphyrin levels in the blood increased as the percentage of lead-contaminated sediment in the diet increased. Birds fed 24% lead-contaminated sediment exhibited atrophy of the breast muscles, green staining of the feathers around the vent, viscous bile, green staining of the gizzard lining, and renal tubular intranuclear inclusion bodies. Mallards fed 24% lead-contaminated sediment had means of 6.1 μg/g of lead in the blood and 28 μg/g in the liver (wet-weight basis) and 1,660 μg/g in the feces (dry-weight basis). In experiment 2, we raised the dietary concentration of the lead-contaminated sediment to 48%, but only about 20% sediment was actually ingested due to food washing by the birds. Protoporphyrin levels were elevated in the lead-exposed birds, and all of the mallards fed 48% lead-contaminated sediment had renal tubular intranuclear inclusion bodies. The concentrations of lead in the liver were 9.1 μg/g for mallards fed 24% lead-contaminated sediment and 16 μg/g for mallards fed 48% lead-contaminated sediment. In experiment 3, four of five mallards died when fed a ground corn diet containing 24% lead-contaminated sediment (with 4,000 μg/g lead in this sample of sediment), but none died when the 24% lead-contaminated sediment was mixed into a nutritionally balanced commercial duck diet; estimated actual ingestion rates for sediment were 14% and 17% for the corn and commercial diets. Lead exposure caused elevations in protoporphyrin, and four of the five mallards fed 24% lead-contaminated sediment in a commercial diet and all five fed the contaminated sediment in a corn diet had renal intranuclear inclusion bodies. Lead was higher in the livers of mallards fed 24% lead-contaminated sediment in the corn diet (38 μg/g) than in the commercial diet (13 μg/g).

Groundwater contamination downstream of a contaminant penetration site. II. Horizontal penetration of the contaminant plume

USGS Publications Warehouse

Rubin, H.; Buddemeier, R.W.

2002-01-01

Part I of this study (Rubin, H.; Buddemeier, R.W. Groundwater Contamination Downstream of a Contaminant Penetration Site Part 1: Extension-Expansion of the Contaminant Plume. J. of Environmental Science and Health Part A (in press).) addressed cases, in which a comparatively thin contaminated region represented by boundary layers (BLs) developed within the freshwater aquifer close to contaminant penetration site. However, at some distance downstream from the penetration site, the top of the contaminant plume reaches the top or bottom of the aquifer. This is the location of the "attachment point," which comprises the entrance cross section of the domain evaluated by the present part of the study. It is shown that downstream from the entrance cross section, a set of two BLs develop in the aquifer, termed inner and outer BLs. It is assumed that the evaluated domain, in which the contaminant distribution gradually becomes uniform, can be divided into two sections, designated: (a) the restructuring section, and (b) the establishment section. In the restructuring section, the vertical concentration gradient leads to expansion of the inner BL at the expense of the outer BL, and there is almost no transfer of contaminant mass between the two layers. In the establishment section, each of the BLs occupies half of the aquifer thickness, and the vertical concentration gradient leads to transfer of contaminant mass from the inner to the outer BL. By use of BL approximations, changes of salinity distribution in the aquifer are calculated and evaluated. The establishment section ends at the uniformity point, downstream from which the contaminant concentration profile is practically uniform. The length of the restructuring section, as well as that of the establishment section, is approximately proportional to the aquifer thickness squared, and is inversely proportional to the transverse dispersivity. The study provides a convenient set of definitions and terminology that are helpful in visualizing the gradual development of uniform contaminant concentration distribution in an aquifer subject to contaminant plume penetration. The method developed in this study can be applied to a variety of problems associated with groundwater quality, such as initial evaluation of field data, design of field data collection, the identification of appropriate boundary conditions for numerical models, selection of appropriate numerical modeling approaches, interpretation and evaluation of field monitoring results, etc.

40 CFR 141.11 - Maximum contaminant levels for inorganic chemicals.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Maximum contaminant levels for inorganic chemicals. 141.11 Section 141.11 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... § 141.11 Maximum contaminant levels for inorganic chemicals. (a) The maximum contaminant level for...

EFFECTS OF A HIGHLY-CONTAMINATED URBAN HARBOR ON AN ESTUARINE FISH SPECIES: ADAPTIVE CHANGES AT SPECIFIC LOCI

EPA Science Inventory

Fundulus heteroclitus populations indigenous to certain highly contaminated sites demonstrate an inherited tolerance to the toxic effects of local chemical contaminants. Our initial studies examining populations of F. heterclitus indigenous to a PCB-contaminated Superfund site at...

Soil Vapor Extraction System Optimization, Transition, and Closure Guidance, PNNL-21843

EPA Science Inventory

Soil vapor extraction (SVE) is a prevalent remediation approach for volatile contaminants in the vadose zone. A diminishing rate of contaminant extraction over time is typically observed due to 1) diminishing contaminant mass, and/or 2) slow rates of removal for contamination in ...

40 CFR 141.66 - Maximum contaminant levels for radionuclides.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 24 2012-07-01 2012-07-01 false Maximum contaminant levels for... Regulations: Maximum Contaminant Levels and Maximum Residual Disinfectant Levels § 141.66 Maximum contaminant levels for radionuclides. (a) [Reserved] (b) MCL for combined radium-226 and -228. The maximum...

40 CFR 141.66 - Maximum contaminant levels for radionuclides.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 23 2014-07-01 2014-07-01 false Maximum contaminant levels for... Regulations: Maximum Contaminant Levels and Maximum Residual Disinfectant Levels § 141.66 Maximum contaminant levels for radionuclides. (a) [Reserved] (b) MCL for combined radium-226 and -228. The maximum...

40 CFR 141.66 - Maximum contaminant levels for radionuclides.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 24 2013-07-01 2013-07-01 false Maximum contaminant levels for... Regulations: Maximum Contaminant Levels and Maximum Residual Disinfectant Levels § 141.66 Maximum contaminant levels for radionuclides. (a) [Reserved] (b) MCL for combined radium-226 and -228. The maximum...

40 CFR 141.66 - Maximum contaminant levels for radionuclides.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 23 2011-07-01 2011-07-01 false Maximum contaminant levels for... Regulations: Maximum Contaminant Levels and Maximum Residual Disinfectant Levels § 141.66 Maximum contaminant levels for radionuclides. (a) [Reserved] (b) MCL for combined radium-226 and -228. The maximum...

40 CFR 141.11 - Maximum contaminant levels for inorganic chemicals.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 23 2014-07-01 2014-07-01 false Maximum contaminant levels for inorganic chemicals. 141.11 Section 141.11 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... § 141.11 Maximum contaminant levels for inorganic chemicals. (a) The maximum contaminant level for...

40 CFR 141.11 - Maximum contaminant levels for inorganic chemicals.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 24 2012-07-01 2012-07-01 false Maximum contaminant levels for inorganic chemicals. 141.11 Section 141.11 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... § 141.11 Maximum contaminant levels for inorganic chemicals. (a) The maximum contaminant level for...

EFFECTS OF A HIGHLY-CONTAMINATED URBAN HARBOR ON AN ESTUARINE FISH SPECIES: NEUTRAL MARKERS OF POPULATION GENETIC STRUCTURE

EPA Science Inventory

Fundulus heteroclitus populations indigenous to certain highly contaminated sites demonstrate an inherited tolerance to the toxic effects of local chemical contaminants. Our initial studies examining populations of F. heterclitus indigenous to a PCB-contaminated Superfund site at...

COMBINATION OF A SOURCE REMOVAL REMEDY AND BIOREMEDIATION FOR THE TREATMENT OF A TCE CONTAMINATED AQUIFER

EPA Science Inventory

Historical disposal practices of chlorinated solvents have resulted in the widespread contamination of ground-water resources. These ground-water contaminants exist in the subsurface as free products, residual and vapor phases, and in solution. The remediation of these contamin...

NHEERL CONTAMINATED SEDIMENT RESEARCH MULTI-YEAR IMPLEMENTATION PLAN (2005)

EPA Science Inventory

ORD has developed a multi-year plan (MYP) called the Contaminated Sites MYP to address the research needs of EPA's Office of Superfund Remediation and Technology Innovation (OSRTI). One of the long-term goals of the Contaminated Sites MYP relates to contaminated sediments, and t...

Meaning and Mental Contamination: Focus on Appraisals

ERIC Educational Resources Information Center

Elliott, Corinna M.; Radomsky, Adam S.

2013-01-01

Background: The recent expansion of interest in contamination-related obsessive-compulsive disorder (OCD) has fostered the description of mental contamination and a series of experiments designed to understand associated factors. This supports a cognitive approach to the understanding and treatment of contamination-related OCD--especially when the…

Contamination or changes of food factors during processing and modleing-safety related issue

USDA-ARS?s Scientific Manuscript database

Cross-contamination and food property changes, including chemical and physical, are common during food processing and preservation. The contamination may involve microbial and chemical aspects resulted in food-borne pathogen outbreaks and/or poisons. Chemical contaminations are most likely from th...

40 CFR 52.1988 - Air contaminant discharge permits.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Air contaminant discharge permits. 52... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) Oregon § 52.1988 Air contaminant... other provisions contained in Air Contaminant Discharge Permits issued by the State in accordance with...

Method for selectively removing fluorine and fluorine-containing contaminants from gaseous UF.sub.6

DOEpatents

Jones, Robert L.; Otey, Milton G.; Perkins, Roy W.

1982-01-01

This invention is a method for effecting preferential removal and immobilization of certain gaseous contaminants from gaseous UF.sub.6. The contaminants include fluorine and fluorides which are more reactive with CaCO.sub.3 than is UF.sub.6. The method comprises contacting the contaminant-carrying UF.sub.6 with particulate CaCO.sub.3 at a temperature effecting reaction of the contaminant and the CaCO.sub.3.

Development of a preprototype trace contaminant control system. [for space stations

NASA Technical Reports Server (NTRS)

1977-01-01

The steady state contaminant load model based on shuttle equipment and material test programs, and on the current space station studies was revised. An emergency upset contaminant load model based on anticipated emergency upsets that could occur in an operational space station was defined. Control methods for the contaminants generated by the emergency upsets were established by test. Preliminary designs of both steady state and emergency contaminant control systems for the space station application are presented.

A behavioral test of contamination fear in excessive health anxiety.

PubMed

Brady, Robert E; Lohr, Jeffrey M

2014-03-01

Health anxiety is characterized by a preoccupation with the possibility of having a serious health condition or disease. Contemporary conceptualizations of health anxiety have improved in recent years to incorporate a fear of acquiring an illness; however, there is limited experimental data demonstrating the presence of fear of contamination among health anxious individuals. The present study utilized behavior approach tasks (BATs) to examine the degree to which contamination fear is present in elevated health anxiety. Participants were 60 undergraduate students who reported elevated health anxiety, contamination fear, or no anxiety about either health or contamination. Participants completed four BATS from which avoidance, anxiety, and disgust ratings were derived. Health anxious and contamination fearful individuals exhibited a similar degree of avoidance during the BATs. Contamination fearful participants reported significantly more anxiety and disgust relative to the non-anxious controls, but not the health anxious participants. Health anxious participants did not report more anxiety or disgust than the non-anxious participants. The use of an analogue sample may limit the extension of these findings to clinical populations. Additionally, the role of general negative affect could not be reliably determined in the absence of an anxious control group. These findings suggest that contamination fear may be a source of conceptual overlap between health anxiety and other disorders characterized by contamination fear. This highlights the importance of considering contamination fear in excessive health anxiety. Published by Elsevier Ltd.

Real-time determination of the efficacy of residual disinfection to limit wastewater contamination in a water distribution system using filtration-based luminescence.

PubMed

Lee, Jiyoung; Deininger, Rolf A

2010-05-01

Water distribution systems can be vulnerable to microbial contamination through cross-connections, wastewater backflow, the intrusion of soiled water after a loss of pressure resulting from an electricity blackout, natural disaster, or intentional contamination of the system in a bioterrrorism event. The most urgent matter a water treatment utility would face in this situation is detecting the presence and extent of a contamination event in real-time, so that immediate action can be taken to mitigate the problem. The current approved microbiological detection methods are culture-based plate count methods, which require incubation time (1 to 7 days). This long period of time would not be useful for the protection of public health. This study was designed to simulate wastewater intrusion in a water distribution system. The objectives were 2-fold: (1) real-time detection of water contamination, and (2) investigation of the sustainability of drinking water systems to suppress the contamination with secondary disinfectant residuals (chlorine and chloramine). The events of drinking water contamination resulting from a wastewater addition were determined by filtration-based luminescence assay. The water contamination was detected by luminescence method within 5 minutes. The signal amplification attributed to wastewater contamination was clear-102-fold signal increase. After 1 hour, chlorinated water could inactivate 98.8% of the bacterial contaminant, while chloraminated water reduced 77.2%.

Microbial contamination in intraoral phosphor storage plates: the dilemma.

PubMed

de Souza, Tricia Murielly Pereira Andrade; de Castro, Ricardo Dias; de Vasconcelos, Laís César; Pontual, Andréa Dos Anjos; de Moraes Ramos Perez, Flávia Maria; Pontual, Maria Luiza Dos Anjos

2017-01-01

The aims of this study were to evaluate microbial contamination in phosphor storage plates in dental radiology services and discuss the possible origin of this contamination. The sample comprised 50 phosphor plates: 14 plates from service A, 30 from service B, and 6 in the control group, consisting of plates never used. Damp sterile swabs were rubbed on the phosphor plates, and then transferred to tests tubes containing sterile saline solution. Serial dilutions were made, and then inoculated in triplicate on Mueller Hinton agar plates and incubated at 37 °C/48 h, before counting the colony-forming units (CFU). The samples were also seeded in brain-heart infusion medium to confirm contamination by turbidity of the culture medium. All solutions, turbid and clean, were seeded in selective and non-selective media. At service A and B, 50 and 73.3 % of the phosphor plates were contaminated, respectively. This contamination was mainly due to bacteria of the genus Staphylococcus. CFU counts ranged from 26.4 to 80.0 CFU/plate. Most of the phosphor plates evaluated shown to be contaminated, mainly by Staphylococcus ssp. Quantitatively, this contamination occurred at low levels, possibly arising from handling of the plates. The use of a second plastic barrier may have diminished contamination by microorganisms from the oral cavity. There is a risk of cross-contamination by phosphor storage plates used in dental radiology services.

Assessing groundwater vulnerability to agrichemical contamination in the Midwest US

USGS Publications Warehouse

Burkart, M.R.; Kolpin, D.W.; James, D.E.

1999-01-01

Agrichemicals (herbicides and nitrate) are significant sources of diffuse pollution to groundwater. Indirect methods are needed to assess the potential for groundwater contamination by diffuse sources because groundwater monitoring is too costly to adequately define the geographic extent of contamination at a regional or national scale. This paper presents examples of the application of statistical, overlay and index, and process-based modeling methods for groundwater vulnerability assessments to a variety of data from the Midwest U.S. The principles for vulnerability assessment include both intrinsic (pedologic, climatologic, and hydrogeologic factors) and specific (contaminant and other anthropogenic factors) vulnerability of a location. Statistical methods use the frequency of contaminant occurrence, contaminant concentration, or contamination probability as a response variable. Statistical assessments are useful for defining the relations among explanatory and response variables whether they define intrinsic or specific vulnerability. Multivariate statistical analyses are useful for ranking variables critical to estimating water quality responses of interest. Overlay and index methods involve intersecting maps of intrinsic and specific vulnerability properties and indexing the variables by applying appropriate weights. Deterministic models use process-based equations to simulate contaminant transport and are distinguished from the other methods in their potential to predict contaminant transport in both space and time. An example of a one-dimensional leaching model linked to a geographic information system (GIS) to define a regional metamodel for contamination in the Midwest is included.

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

Transport and transformations of chlorinated-solvent contamination in a saprolite and fractured rock aquifer near a former wastewater-treatment plant, Greenville, South Carolina

USGS Publications Warehouse

Vroblesky, D.A.; Bradley, P.M.; Lane, J.W.; Robertson, J.F.

1997-01-01

The transport and fate of chlorinated-ethene contamination was investigated in a fractured-rock aquifer downgradient from a wastewater-treatment plant at a gas-turbine manufacturing facility in Greenville, South Carolina. A vapor-diffusion-sampler technique, developed for this investigation, located fracture zones that discharged contaminated ground water to surface water. The distribution of chlorinated compounds and sulfate, comparison of borehole geophysical data, driller's logs, and the aquifer response to pumpage allowed subsurface contaminant-transport pathways to be delineated.The probable contaminant-transport pathway from the former aeration lagoon was southward. The probable pathway of contaminant transport from the former sludge lagoon was southward to and beneath Little Rocky Creek. South of the creek, the major pathway of contaminant transport appeared to be at a depth of approximately 80 to 107 feet below land surface. The contaminant-transport pathway from the former industrial lagoon was not readily discernible from existing data. A laboratory investigation, as well as examination of ground- water-chemistry data collected during this investigation and concentrations of chlorinated compounds collected during previous investigations,indicates that higher chlorinated compounds are being degraded to lower-chlorinated compounds in the contaminated aquifer. The approaches used in this investigation, as well as the findings, have potential application to other fractured-rock aquifers contaminated by chlorinated ethenes.

Rapid intrinsic biodegradation of benzene, toluene, and xylenes at the boundary of a gasoline-contaminated plume under natural attenuation.

PubMed

Takahata, Yoh; Kasai, Yuki; Hoaki, Toshihiro; Watanabe, Kazuya

2006-12-01

A groundwater plume contaminated with gasoline constituents [mainly benzene, toluene, and xylenes (BTX)] had been treated by pumping and aeration for approximately 10 years, and the treatment strategy was recently changed to monitored natural attenuation (MNA). To gain information on the feasibility of using MNA to control the spread of BTX, chemical and microbiological parameters in groundwater samples obtained inside and outside the contaminated plume were measured over the course of 73 weeks. The depletion of electron acceptors (i.e., dissolved oxygen, nitrate, and sulfate) and increase of soluble iron were observed in the contaminated zone. Laboratory incubation tests revealed that groundwater obtained immediately outside the contaminated zone (the boundary zone) exhibited much higher potential for BTX degradation than those in the contaminated zone and in uncontaminated background zones. The boundary zone was a former contaminated area where BTX were no longer detected. Denaturing gradient gel electrophoresis (DGGE) analysis of polymerase chain reaction (PCR)-amplified bacterial 16S rRNA gene fragments revealed that DGGE profiles for groundwater samples obtained from the contaminated zone were clustered together and distinct from those from uncontaminated zones. In addition, unique bacterial rRNA types were observed in the boundary zone. These results indicate that the boundary zone in the contaminant plumes served as a natural barrier for preventing the BTX contamination from spreading out.

Detection by denaturing gradient gel electrophoresis of ammonia-oxidizing bacteria in microcosms of crude oil-contaminated mangrove sediments.

PubMed

dos Santos, A C F; Marques, E L S; Gross, E; Souza, S S; Dias, J C T; Brendel, M; Rezende, R P

2012-01-27

Currently, the effect of crude oil on ammonia-oxidizing bacterium communities from mangrove sediments is little understood. We studied the diversity of ammonia-oxidizing bacteria in mangrove microcosm experiments using mangrove sediments contaminated with 0.1, 0.5, 1, 2, and 5% crude oil as well as non-contaminated control and landfarm soil from near an oil refinery in Camamu Bay in Bahia, Brazil. The evolution of CO(2) production in all crude oil-contaminated microcosms showed potential for mineralization. Cluster analysis of denaturing gradient gel electrophoresis-derived samples generated with primers for gene amoA, which encodes the functional enzyme ammonia monooxygenase, showed differences in the sample contaminated with 5% compared to the other samples. Principal component analysis showed divergence of the non-contaminated samples from the 5% crude oil-contaminated sediment. A Venn diagram generated from the banding pattern of PCR-denaturing gradient gel electrophoresis was used to look for operational taxonomic units (OTUs) in common. Eight OTUs were found in non-contaminated sediments and in samples contaminated with 0.5, 1, or 2% crude oil. A Jaccard similarity index of 50% was found for samples contaminated with 0.1, 0.5, 1, and 2% crude oil. This is the first study that focuses on the impact of crude oil on the ammonia-oxidizing bacterium community in mangrove sediments from Camamu Bay.

Simulating Mobility of Chemical Contaminants from Unconventional Gas Development for Protection of Water Resources

NASA Astrophysics Data System (ADS)

Kanno, C.; Edlin, D.; Borrillo-Hutter, T.; McCray, J. E.

2014-12-01

Potential contamination of ground water and surface water supplies from chemical contaminants in hydraulic fracturing fluids or in natural gas is of high public concern. However, quantitative assessments have rarely been conducted at specific energy-producing locations so that the true risk of contamination can be evaluated. The most likely pathways for contamination are surface spills and faulty well bores that leak production fluids directly into an aquifer. This study conducts fate and transport simulations of the most mobile chemical contaminants, based on reactivity to subsurface soils, degradation potential, and source concentration, to better understand which chemicals are most likely to contaminate water resources, and to provide information to planners who wish to be prepared for accidental releases. The simulations are intended to be most relevant to the Niobrara shale formation.

Airborne agent concentration analysis

DOEpatents

Gelbard, Fred

2004-02-03

A method and system for inferring airborne contaminant concentrations in rooms without contaminant sensors, based on data collected by contaminant sensors in other rooms of a building, using known airflow interconnectivity data. The method solves a least squares problem that minimizes the difference between measured and predicted contaminant sensor concentrations with respect to an unknown contaminant release time. Solutions are constrained to providing non-negative initial contaminant concentrations in all rooms. The method can be used to identify a near-optimal distribution of sensors within the building, when then number of available sensors is less than the total number of rooms. This is achieved by having a system-sensor matrix that is non-singular, and by selecting that distribution which yields the lowest condition number of all the distributions considered. The method can predict one or more contaminant initial release points from the collected data.

JPL Contamination Control Engineering

NASA Technical Reports Server (NTRS)

Blakkolb, Brian

2013-01-01

JPL has extensive expertise fielding contamination sensitive missions-in house and with our NASA/industry/academic partners.t Development and implementation of performance-driven cleanliness requirements for a wide range missions and payloads - UV-Vis-IR: GALEX, Dawn, Juno, WFPC-II, AIRS, TES, et al - Propulsion, thermal control, robotic sample acquisition systems. Contamination control engineering across the mission life cycle: - System and payload requirements derivation, analysis, and contamination control implementation plans - Hardware Design, Risk trades, Requirements V-V - Assembly, Integration & Test planning and implementation - Launch site operations and launch vehicle/payload integration - Flight ops center dot Personnel on staff have expertise with space materials development and flight experiments. JPL has capabilities and expertise to successfully address contamination issues presented by space and habitable environments. JPL has extensive experience fielding and managing contamination sensitive missions. Excellent working relationship with the aerospace contamination control engineering community/.

Nanomaterial-enabled Rapid Detection of Water Contaminants.

PubMed

Mao, Shun; Chang, Jingbo; Zhou, Guihua; Chen, Junhong

2015-10-28

Water contaminants, e.g., inorganic chemicals and microorganisms, are critical metrics for water quality monitoring and have significant impacts on human health and plants/organisms living in water. The scope and focus of this review is nanomaterial-based optical, electronic, and electrochemical sensors for rapid detection of water contaminants, e.g., heavy metals, anions, and bacteria. These contaminants are commonly found in different water systems. The importance of water quality monitoring and control demands significant advancement in the detection of contaminants in water because current sensing technologies for water contaminants have limitations. The advantages of nanomaterial-based sensing technologies are highlighted and recent progress on nanomaterial-based sensors for rapid water contaminant detection is discussed. An outlook for future research into this rapidly growing field is also provided. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Radioactive contamination of the Balchug (Upper Yenisey) floodplain, Russia in relation to sedimentation processes and geomorphology.

PubMed

Linnik, V G; Brown, J E; Dowdall, M; Potapov, V N; Surkov, V V; Korobova, E M; Volosov, A G; Vakulovsky, S M; Tertyshnik, E G

2005-03-01

The radioactive contamination of a riverine floodplain, heavily influenced by discharges from Krasnoyarsk-26, has been studied with respect to sedimentation processes and the geomorphology of the Upper Yenisey floodplain. The study was effected by implementation of a regime of in situ observations and measurements, sampling, and the interpretation of satellite images. The results of the study indicate that on the Balchug Bypass Floodplain, radionuclide contamination is primarily influenced by the thickness of the deposited sediments, and the area can be considered as two depositional environments. The Balchug floodplain area was contaminated due to sedimentation of radionuclide-contaminated alluvium, whose depositional regime significantly changed after the construction of a hydroelectric power station in 1967. Contamination levels are lower on the upstream part of the floodplain where sediment depth is less than 0.2-0.3 m, and this contamination started to accumulate in 1967, while the downstream part of the floodplain, exhibiting deeper deposits, displays higher levels of radionuclide contamination because radionuclides began to deposit here in 1958 when the Krasnoyarsk-26 Mining and Chemical Combine (KMCC) commenced operation. Radionuclide contamination of the floodplain is also related to the elevation of the floodplain, higher regions of the floodplain typically having lower contamination than low-lying areas, which tend to be frequently inundated with sediments being deposited during such inundations. Local relief, its orientation, and vegetation cover have also combined to form sediment traps with significantly higher radionuclide contamination. Lithological analysis combined with radiometric assay indicates a total 137Cs floodplain inventory of 33.7 GBq.

Validation and Application of Models to Predict Facemask Influenza Contamination in Healthcare Settings

PubMed Central

Fisher, Edward M.; Noti, John D.; Lindsley, William G.; Blachere, Francoise M.; Shaffer, Ronald E.

2015-01-01

Facemasks are part of the hierarchy of interventions used to reduce the transmission of respiratory pathogens by providing a barrier. Two types of facemasks used by healthcare workers are N95 filtering facepiece respirators (FFRs) and surgical masks (SMs). These can become contaminated with respiratory pathogens during use, thus serving as potential sources for transmission. However, because of the lack of field studies, the hazard associated with pathogen-exposed facemasks is unknown. A mathematical model was used to calculate the potential influenza contamination of facemasks from aerosol sources in various exposure scenarios. The aerosol model was validated with data from previous laboratory studies using facemasks mounted on headforms in a simulated healthcare room. The model was then used to estimate facemask contamination levels in three scenarios generated with input parameters from the literature. A second model estimated facemask contamination from a cough. It was determined that contamination levels from a single cough (≈19 viruses) were much less than likely levels from aerosols (4,473 viruses on FFRs and 3,476 viruses on SMs). For aerosol contamination, a range of input values from the literature resulted in wide variation in estimated facemask contamination levels (13–202,549 viruses), depending on the values selected. Overall, these models and estimates for facemask contamination levels can be used to inform infection control practice and research related to the development of better facemasks, to characterize airborne contamination levels, and to assist in assessment of risk from reaerosolization and fomite transfer because of handling and reuse of contaminated facemasks. PMID:24593662

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.

Indirect latex glove contamination and its inhibitory effect on vinyl polysiloxane polymerization.

PubMed

Kimoto, Katsuhiko; Tanaka, Kinya; Toyoda, Minoru; Ochiai, Kent T

2005-05-01

The inhibitory effect of indirect latex contamination on the polymerization of vinyl polysiloxane (VPS) impression material has been previously reported. However, the transfer of specific elements that cause inhibition has not been confirmed, nor has the removal of such contaminants been reported. This study examined the surfaces of materials commonly used in restorative procedures that were contaminated by indirect latex glove contact and then evaluated for inhibition of polymerization of VPS. The effect of selected cleansing procedures was then studied. Four experimental groups (n = 8) were prepared: (1) clean vinyl gloves (control), (2) clean gingival retraction cords (control), (3) contaminated vinyl gloves, and (4) contaminated gingival retraction cord. Microscopic evaluation of the appearance and the characterization of surface particulate contamination were performed for each. Three cleansing protocols were then evaluated for efficacy in cleaning vinyl glove surfaces contaminated by latex contact (n = 10): (1) brushing with water, (2) brushing with soap/rinsing with water, (3) cleansing with rubbing alcohol. The subsequent degree of VPS polymerization inhibition was evaluated subjectively. A chi-square test was used for data analysis (alpha=.05). Particulate sulfur elements and sulfur-chloride compounds were present on the contaminated substrates. None of the 3 cleansing procedures eliminated polymerization inhibition (P =.33). Residual elemental sulfur remained on all tested surfaces. Particulate sulfur and sulfur-chloride compounds were identified as the particulate contamination that resulted in polymerization inhibition of the tested VPS dental impression material. Removal of these contaminants from the tested vinyl gloves and gingival retraction cord was not possible with the 3 cleansing protocols tested in this study.

30 CFR 56.5005 - Control of exposure to airborne contaminants.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Control of exposure to airborne contaminants... Air Quality and Physical Agents Air Quality § 56.5005 Control of exposure to airborne contaminants. Control of employee exposure to harmful airborne contaminants shall be, insofar as feasible, by prevention...

Microbial Contamination of Chicken Wings: An Open-Ended Laboratory Project.

ERIC Educational Resources Information Center

Deutch, Charles E.

2001-01-01

Introduces the chicken wing project in which students assess the microbial contamination of chicken wings for the safety of foods. Uses the colony counting technique and direct wash fluid examination for determining the microbial contamination, and investigates methods to reduce the level of microbial contamination. (Contains 14 references.) (YDS)

The Contribution of Food Safety Management Systems to the Prevention of Deliberate Food Contamination

NASA Astrophysics Data System (ADS)

Smith, Madeleine

Food Safety Management systems such as HACCP can help to prevent deliberate contamination of food. These systems are widely used already by the food industry to prevent accidental contamination. This makes them an attractive and cost effective way to address the issue of deliberate contamination.

Super Shedding of Escherichia coli O157:H7 by Cattle and the Impact on Beef Carcass Contamination

USDA-ARS?s Scientific Manuscript database

Beef carcass contamination is a direct result of pathogen transfer from cattle hides harboring organisms such as enterohemorrhagic E. coli. Hide contamination occurs from direct and indirect fecal contamination in cattle production and lairage environments. In each of these environments, individua...

Current university and USDA lab cotton contamination research

USDA-ARS?s Scientific Manuscript database

U.S. cotton is considered to have some of the lowest levels of contamination in the world. However, that reputation is in jeopardy as complaints of contamination from domestic and foreign mills are on the rise. Cotton contamination can be classified under four major categorizes: fabrics and strings ...

40 CFR 142.65 - Variances and exemptions from the maximum contaminant levels for radionuclides.

Code of Federal Regulations, 2013 CFR

2013-07-01

... maximum contaminant levels for radionuclides. 142.65 Section 142.65 Protection of Environment... Available § 142.65 Variances and exemptions from the maximum contaminant levels for radionuclides. (a)(1) Variances and exemptions from the maximum contaminant levels for combined radium-226 and radium-228, uranium...

40 CFR 142.65 - Variances and exemptions from the maximum contaminant levels for radionuclides.

Code of Federal Regulations, 2012 CFR

2012-07-01

... maximum contaminant levels for radionuclides. 142.65 Section 142.65 Protection of Environment... Available § 142.65 Variances and exemptions from the maximum contaminant levels for radionuclides. (a)(1) Variances and exemptions from the maximum contaminant levels for combined radium-226 and radium-228, uranium...

40 CFR 142.65 - Variances and exemptions from the maximum contaminant levels for radionuclides.

Code of Federal Regulations, 2014 CFR

2014-07-01

... maximum contaminant levels for radionuclides. 142.65 Section 142.65 Protection of Environment... Available § 142.65 Variances and exemptions from the maximum contaminant levels for radionuclides. (a)(1) Variances and exemptions from the maximum contaminant levels for combined radium-226 and radium-228, uranium...

40 CFR 142.65 - Variances and exemptions from the maximum contaminant levels for radionuclides.

Code of Federal Regulations, 2011 CFR

2011-07-01

... maximum contaminant levels for radionuclides. 142.65 Section 142.65 Protection of Environment... Available § 142.65 Variances and exemptions from the maximum contaminant levels for radionuclides. (a)(1) Variances and exemptions from the maximum contaminant levels for combined radium-226 and radium-228, uranium...

32 CFR 644.520 - Contaminated industrial property.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 32 National Defense 4 2011-07-01 2011-07-01 false Contaminated industrial property. 644.520... Excess Land and Improvements § 644.520 Contaminated industrial property. (a) GSA may arrange to sell contaminated chemical or other industrial plants to a purchaser whose operations will result in the same type...

32 CFR 644.520 - Contaminated industrial property.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 32 National Defense 4 2010-07-01 2010-07-01 true Contaminated industrial property. 644.520 Section... Excess Land and Improvements § 644.520 Contaminated industrial property. (a) GSA may arrange to sell contaminated chemical or other industrial plants to a purchaser whose operations will result in the same type...

41 CFR 109-42.1102-52 - Low level contaminated personal property.

Code of Federal Regulations, 2010 CFR

2010-07-01

... contamination does not exceed applicable standards, it may be utilized and disposed of in the same manner as.... However, recipients shall be advised where levels of radioactive contamination require specific controls... within DOE, reported to GSA, or otherwise disposed of, the kind and degree of contamination must be...

32 CFR 644.530 - Conditions in conveying land suspected of contamination.

Code of Federal Regulations, 2010 CFR

2010-07-01

... contamination. 644.530 Section 644.530 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY... Contamination from Proposed Excess Land and Improvements § 644.530 Conditions in conveying land suspected of contamination. The following conditions, appropriately modified to conform to local law, will be included in...

78 FR 47228 - Airworthiness Directives; Thielert Aircraft Engines GmbH Reciprocating Engines

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-05

... allows the crankcase assembly opening to be susceptible to contamination from external sources. This... contamination of the engine clutch by coolant spillage during the last maintenance operation. The contamination.... The design of the engine allows the crankcase assembly opening to be susceptible to contamination from...

49 CFR 177.843 - Contamination of vehicles.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Contamination of vehicles. 177.843 Section 177.843... and Unloading § 177.843 Contamination of vehicles. (a) Each motor vehicle used for transporting Class... surface contamination is not greater than the level prescribed in § 173.443(a) of this subchapter. (b...

ORGANIC CONTAMINANT DISTRIBUTION IN SEDIMENTS, POLYCHAETES (NEREIS VIRENS) AND THE AMERICAN LOBSTER, HOMARUS AMERICANUS IN A LABORATORY FOOD CHAIN EXPERIMENT

EPA Science Inventory

A laboratory experiment was conducted to investigate the transfer of organic contaminants from an environmentally contaminated marine sediment through a simple marine food chain. The infaunal polychaete, Nereis virens, was exposed to contaminated sediment collected from the Passa...

USDA and university researchers work to prevent U.S. cotton contamination

USDA-ARS?s Scientific Manuscript database

U.S. cotton is considered to have some of the lowest levels of contamination in the world. However, that reputation is in jeopardy as complaints of contamination from domestic and foreign mills are on the rise. Cotton contamination is classified by the International Textile Manufacturers Federation ...

40 CFR Appendix I to Part 257 - Maximum Contaminant Levels (MCLs)

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Maximum Contaminant Levels (MCLs) I Appendix I to Part 257 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES... Part 257—Maximum Contaminant Levels (MCLs) Maximum Contaminant Levels (MCLs) Promulgated Under the Safe...

Development of a U.S. EPA Method for the Analysis of Selected Drinking Water Contaminants by LC/MS/MS

EPA Science Inventory

The U.S. Environmental Protection Agency’s (U.S. EPA) Office of Ground Water and Drinking Water (OGWDW) collects national occurrence data on drinking water contaminants using Unregulated Contaminant Monitoring Regulations (UCMRs). These contaminants may be selected from the Drin...

9 CFR 113.30 - Detection of Salmonella contamination.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Detection of Salmonella contamination... REQUIREMENTS Standard Procedures § 113.30 Detection of Salmonella contamination. The test for detection of Salmonella contamination provided in this section shall be conducted when such a test is prescribed in an...

9 CFR 113.30 - Detection of Salmonella contamination.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Detection of Salmonella contamination... REQUIREMENTS Standard Procedures § 113.30 Detection of Salmonella contamination. The test for detection of Salmonella contamination provided in this section shall be conducted when such a test is prescribed in an...

Application of passive sampling for measuring dissolved concentrations of organic contaminants in the water column at three marine superfund sites

EPA Science Inventory

At contaminated sediment sites, including U.S. EPA Superfund sites, it is critical to measure water column concentrations of freely dissolved contaminants to understand the complete exposure of aquatic organisms to hydrophobic organic contaminants (HOCs). However, historically a...

LINKING GREAT WATERSHEDS AND RIVERS TO FORECAST THE IMPACT OF CONTAMINANT STRESSORS ON LARGE RECEIVING WATERS

EPA Science Inventory

Contaminated sediments are pervasive within the waters of the nation. A number of contaminants are bioaccumulative and are an unacceptable risk to the ecosystem, including humans. Many sites having contaminated sediments are contained within state 305(b) and 303(d) listings and w...

USE OF NETWORK MODELS FOR ESTIMATING EXPOSURE OF CONSUMERS TO CONTAMINANTS IN DRINKING WATER DISTRIBUTION SYSTEMS

EPA Science Inventory

The presence of contaminants in a drinking water distribution system can result in exposure of consumers to contaminated water. Whether the contaminants result from waterborne outbreaks that accidentally enter the system or through purposeful acts, the movement of the resulting ...

21 CFR 211.176 - Penicillin contamination.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 4 2014-04-01 2014-04-01 false Penicillin contamination. 211.176 Section 211.176... Penicillin contamination. If a reasonable possibility exists that a non-penicillin drug product has been exposed to cross-contamination with penicillin, the non-penicillin drug product shall be tested for the...

21 CFR 211.176 - Penicillin contamination.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 4 2012-04-01 2012-04-01 false Penicillin contamination. 211.176 Section 211.176... Penicillin contamination. If a reasonable possibility exists that a non-penicillin drug product has been exposed to cross-contamination with penicillin, the non-penicillin drug product shall be tested for the...

21 CFR 211.176 - Penicillin contamination.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 4 2011-04-01 2011-04-01 false Penicillin contamination. 211.176 Section 211.176... Penicillin contamination. If a reasonable possibility exists that a non-penicillin drug product has been exposed to cross-contamination with penicillin, the non-penicillin drug product shall be tested for the...

21 CFR 211.176 - Penicillin contamination.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 4 2013-04-01 2013-04-01 false Penicillin contamination. 211.176 Section 211.176... Penicillin contamination. If a reasonable possibility exists that a non-penicillin drug product has been exposed to cross-contamination with penicillin, the non-penicillin drug product shall be tested for the...

PHYSICAL, CHEMICAL AND BIOLOGICAL TOOLS FOR EVALUATING, MONITORED NATURAL RECOVERY OF PCB CONTAMINATED SEDIMENTS IN LAKE HARTWELL, CLEMSON, SC

EPA Science Inventory

Management of contaminated sediments poses significant challenges due to varied contaminants and volumes of sediments to
manage. Dredging, capping, and monitored natural recovery (MNR) are the primary approaches for managing the contaminated sediment risks.
Understanding ho...

A MULTI-ORD LAB AND REGIONAL ASSESSMENT OF MONITORED NATURAL RECOVERY OF PCB-CONTAMINATED SEDIMENTS IN LAKE HARTWELL, CLEMSON, SC

EPA Science Inventory

Management of contaminated sediments poses many challenges due to varied contaminants and volumes of sediments to manage. Dredging, capping, and monitored natural recovery (MNR) are the primary approaches for managing the contaminated sediment risks. Understanding how well the ...

A PHYSICAL, CHEMICAL, AND BIOLOGICAL ASSESSMENT OF MONITORED NATURAL RECOVERY OF PCB-CONTAMINATED SEDIMENTS IN LAKE HARTWELL, CLEMSON, NC

EPA Science Inventory

Management of contaminated sediments poses significant challenges due to varied contaminants and volumes of sediments to manage. Dredging, capping, and monitored natural recovery (MNR) are the primary approaches for managing the contaminated sediment risks. Understanding how eff...

Management of Irradiated and Contaminated Casualty Victims

DTIC Science & Technology

1984-08-01

such as those that appear to be "dirty," should have the contamination brushed away or wiped away. At this point the patient should be surveyed for...contamination. Hair should be shampooed with a mild shampoo . Should contamination be present within the external ear canals, the nose, or the mouth, these

76 FR 31271 - Public Meeting: Preliminary Regulatory Determinations for the Third Contaminant Candidate List...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-31

... Regulatory Determinations for the Third Contaminant Candidate List (CCL 3) AGENCY: Environmental Protection... require the EPA to determine every five years, whether to regulate at least five contaminants from the current Contaminant Candidate List (CCL) with a national primary drinking water regulation. The process of...

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.

A Study of Space Station Contamination Effects. [conference

NASA Technical Reports Server (NTRS)

Torr, M. R. (Editor); Spann, J. F. (Editor); Moorehead, T. W. (Editor)

1988-01-01

A workshop was held with the specific objective of reviewing the state-of-knowledge regarding Space Station contamination, the extent to which the various categories of contamination can be predicted, and the extent to which the predicted levels would interfere with onboard scientific investigations or space station functions. The papers presented at the workshop are compiled and address the following topics: natural environment, plasma electromagnetic environment, optical environment, particulate environment, spacecraft contamination, surface physics processes, laboratory experiments and vented chemicals/contaminants.

Feed gas contaminant removal in ion transport membrane systems

DOEpatents

Underwood, Richard Paul [Allentown, PA; Makitka, III, Alexander; Carolan, Michael Francis [Allentown, PA

2012-04-03

An oxygen ion transport membrane process wherein a heated oxygen-containing gas having one or more contaminants is contacted with a reactive solid material to remove the one or more contaminants. The reactive solid material is provided as a deposit on a support. The one or more contaminant compounds in the heated oxygen-containing gas react with the reactive solid material. The contaminant-depleted oxygen-containing gas is contacted with a membrane, and oxygen is transported through the membrane to provide transported oxygen.

Strippable containment and decontamination coating composition and method of use

DOEpatents

Moore, Robert C [Edgewood, NM; Tucker, Mark D [Albuquerque, NM; Jones, Joseph A [Albuquerque, NM

2009-04-07

A method for containing at least a portion of radioisotopes, radionuclides, heavy metal or combination thereof contaminating a substrate wherein a containment composition is applied to the substrate. The ingredients within the containment composition interact with the contaminants on the surface of the substrate until the containment composition has polymerized to a water insoluble form containing at least a portion of the contaminates enmeshed therein. The dried composition is removed from the contaminated surface removing with the composition at least a portion of the contaminate.

Contamination monitoring approaches for EUV space optics

NASA Technical Reports Server (NTRS)

Ray, David C.; Malina, Roger F.; Welsh, Barry J.; Battel, Steven J.

1989-01-01

Data from contaminant-induced UV optics degradation studies and particulate models are used here to develop end-of-service-life instrument contamination requirements which are very stringent but achievable. The budget is divided into allocations for each phase of hardware processing. Optical and nonoptical hardware are monitored for particulate and molecular contamination during initial cleaning and baking, assembly, test, and calibration phases. The measured contamination levels are compared to the requirements developed for each phase to provide confidence that the required end-of-life levels will be met.

Photo-activated luminescence sensor and method of detecting trichloroethylene and related volatile organochloride compounds

DOEpatents

Dinh, Tuan V.

1996-01-01

A sensor for detecting trichloroethylene and related volatile organochloride compounds uses a photo-activator that produces a photo-product complex with the contaminant. Characteristics of the light emitted from the complex will indicate the presence of the contaminant. A probe containing the photo-activator has an excitation light interface and a contaminant interface. One particular embodiment uses a porous membrane as the contaminant interface, so that the contaminant can migrate therethrough to the photo-activator and thereby form the complex.

Method of improving fuel cell performance by removing at least one metal oxide contaminant from a fuel cell electrode

DOEpatents

Kim, Yu Seung [Los Alamos, NM; Choi, Jong-Ho [Los Alamos, NM; Zelenay, Piotr [Los Alamos, NM

2009-08-18

A method of removing contaminants from a fuel cell catalyst electrode. The method includes providing a getter electrode and a fuel cell catalyst electrode having at least one contaminant to a bath and applying a voltage sufficient to drive the contaminant from the fuel cell catalyst electrode to the getter electrode. Methods of removing contaminants from a membrane electrode assembly of a fuel cell and of improving performance of a fuel cell are also provided.

Method for selectively removing fluorine and fluorine-containing contaminants from gaseous UF/sub 6/. [ClF/sub 3/

DOEpatents

Jones, R.L.; Otey, M.G.; Perkins, R.W.

1980-11-24

This invention is a method for effecting preferential removal and immobilization of certain gaseous contaminants from gaseous UF/sub 6/. The contaminants include fluorine and fluorides which are more reactive with CaCO/sub 3/ than is UF/sub 6/. The method comprises contacting the contaminant-carrying UF/sub 6/ with particulate CaCO/sub 3/ at a temperature effecting reaction of the contaminant and the CaCO/sub 3/.

Monitoring Potential Transport of Radioactive Contaminants in Shallow Ephemeral Channels: FY2015 and FY2016

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

Mizell, Steve A; Miller, Julianne J; McCurdy, Greg

The Desert Research Institute (DRI) is conducting a field assessment of the potential for contaminated soil to be transported from the Smoky Contamination Area (CA) as a result of storm runoff. This activity supports Nevada Nuclear Security Administration (NNSA) efforts to complete regulatory closure of the Soils Corrective Action Unit (CAU) contamination areas. The work is intended to confirm the likely mechanism of transport and determine the meteorological conditions that might cause movement of contaminated soils, as well as determine the particle size fraction that is most closely associated with transported radionuclide-contaminated soils. These data will facilitate the appropriate closuremore » design and post-closure monitoring program.« less

Low contaminant formic acid fuel for direct liquid fuel cell

DOEpatents

Masel, Richard I [Champaign, IL; Zhu, Yimin [Urbana, IL; Kahn, Zakia [Palatine, IL; Man, Malcolm [Vancouver, CA

2009-11-17

A low contaminant formic acid fuel is especially suited toward use in a direct organic liquid fuel cell. A fuel of the invention provides high power output that is maintained for a substantial time and the fuel is substantially non-flammable. Specific contaminants and contaminant levels have been identified as being deleterious to the performance of a formic acid fuel in a fuel cell, and embodiments of the invention provide low contaminant fuels that have improved performance compared to known commercial bulk grade and commercial purified grade formic acid fuels. Preferred embodiment fuels (and fuel cells containing such fuels) including low levels of a combination of key contaminants, including acetic acid, methyl formate, and methanol.

Apparatus for removing oil and other floating contaminants from a moving body of water

DOEpatents

Strohecker, J.W.

1973-12-18

The patent describes a process in which floating contaminants such as oil and solid debris are removed from a moving body of water by employing a skimming system which uses the natural gravitational flow of the water. A boom diagonally positioned across the body of water diverts the floating contaminants over a floating weir and into a retention pond where an underflow weir is used to return contaminant-free water to the moving body of water. The floating weir is ballasted to maintain the contaminant-receiving opening therein slightly below the surface of the water during fluctuations in the water level for skimming the contaminants with minimal water removal.

Electron beam influence on the carbon contamination of electron irradiated hydroxyapatite thin films

NASA Astrophysics Data System (ADS)

Hristu, Radu; Stanciu, Stefan G.; Tranca, Denis E.; Stanciu, George A.

2015-08-01

Electron beam irradiation which is considered a reliable method for tailoring the surface charge of hydroxyapatite is hindered by carbon contamination. Separating the effects of the carbon contamination from those of irradiation-induced trapped charge is important for a wide range of biological applications. In this work we focus on the understanding of the electron-beam-induced carbon contamination with special emphasis on the influence of the electron irradiation parameters on this phenomenon. Phase imaging in atomic force microscopy is used to evaluate the influence of electron energy, beam current and irradiation time on the shape and size of the resulted contamination patterns. Different processes involved in the carbon contamination of hydroxyapatite are discussed.

Correlation of the Hubble Space Telescope (HST) Space Telescope Imaging Spectrometer (STIS) On-Orbit Data with Pre-launch Predictions and Ground Contamination Controls

NASA Technical Reports Server (NTRS)

Hansen, Patricia A.

2003-01-01

The Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS) was deployed on-orbit in February 1997. The contamination program for STIS was stringently controlled as the five-year end-of-life deposition was set at 158, per optical element. Contamination was controlled through materials selection, extensive vacuum outgassing certifications, cleaning techniques, and environmental controls. In addition to ground contamination controls, on-orbit contamination controls were implemented for both the HST servicing mission activities and early post-servicing mission checkout. The extensive contamination control program will be discussed and the STIS on-orbit data will be correlated with the prelaunch analytical predictions.

Regenerable Air Purification System for Gas-Phase Contaminant Control

NASA Technical Reports Server (NTRS)

Constantinescu, Ileana C.; Finn, John E.; LeVan, M. Douglas; Lung, Bernadette (Technical Monitor)

2000-01-01

Tests of a pre-prototype regenerable air purification system (RAPS) that uses water vapor to displace adsorbed contaminants from an adsorbent column have been performed at NASA Ames Research Center. A unit based on this design can be used for removing trace gas-phase contaminants from spacecraft cabin air or from polluted process streams including incinerator exhaust. During the normal operation mode, contaminants are removed from the air on the column. Regeneration of the column is performed on-line. During regeneration, contaminants are displaced and destroyed inside the closed oxidation loop. In this presentation we discuss initial experimental results for the performance of RAPS in the removal and treatment of several important spacecraft contaminant species from air.

Exploring Surface Analysis Techniques for the Detection of Molecular Contaminants on Spacecraft

NASA Technical Reports Server (NTRS)

Rutherford, Gugu N.; Seasly, Elaine; Thornblom, Mark; Baughman, James

2016-01-01

Molecular contamination is a known area of concern for spacecraft. To mitigate this risk, projects involving space flight hardware set requirements in a contamination control plan that establishes an allocation budget for the exposure of non-volatile residues (NVR) onto critical surfaces. The purpose of this work will focus on non-contact surface analysis and in situ monitoring to mitigate molecular contamination on space flight hardware. By using Scanning Electron Microscopy and Energy Dispersive Spectroscopy (SEM-EDS) with Raman Spectroscopy, an unlikely contaminant was identified on space flight hardware. Using traditional and surface analysis methods provided the broader view of the contamination sources allowing for best fit solutions to prevent any future exposure.

Carbon contamination in scanning transmission electron microscopy and its impact on phase-plate applications.

PubMed

Hettler, Simon; Dries, Manuel; Hermann, Peter; Obermair, Martin; Gerthsen, Dagmar; Malac, Marek

2017-05-01

We analyze electron-beam induced carbon contamination in a transmission electron microscope. The study is performed on thin films potentially suitable as phase plates for phase-contrast transmission electron microscopy. Electron energy-loss spectroscopy and phase-plate imaging is utilized to analyze the contamination. The deposited contamination layer is identified as a graphitic carbon layer which is not prone to electrostatic charging whereas a non-conductive underlying substrate charges. Several methods that inhibit contamination are evaluated and the impact of carbon contamination on phase-plate imaging is discussed. The findings are in general interesting for scanning transmission electron microscopy applications. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

Enhanced communication and coordination in the public health surveillance component of the Cincinnati Drinking Water Contamination Warning System.

PubMed

Dangel, Chrissy; Allgeier, Steven C; Gibbons, Darcy; Haas, Adam; Simon, Katie

2012-03-01

Effective communication and coordination are critical when investigating a possible drinking water contamination incident. A contamination warning system is designed to detect water contamination by initiating a coordinated, effective response to mitigate significant public health and economic consequences. This article describes historical communication barriers during water contamination incidents and discusses how these barriers were overcome through the public health surveillance component of the Cincinnati Drinking Water Contamination Warning System, referred to as the "Cincinnati Pilot." By enhancing partnerships in the public health surveillance component of the Cincinnati Pilot, information silos that existed in each organization were replaced with interagency information depots that facilitated effective decision making.

Cross-contamination during the preparation of frozen chickens in the kitchen.

PubMed Central

de Wit, J. C.; Broekhuizen, G.; Kampelmacher, E. H.

1979-01-01

A study was made of the extent to which frozen broilers, contaminated with indicator organisms, can cause cross-contamination in the kitchen. In 60 kitchens a number of relevant objects were sampled during the preparation of contaminated frozen broilers. The results show that cross-contamination occurred in a high proportion of the kitchens examined. In many instances the indicator organism was still present on various objects even after rinsing, 'clearing' or washing up. In view of the possible risk of a cross-contamination with Salmonella spp. the importance of instructing food preparers is emphasized. No salmonellas could be found in the sinks of the 60 kitchens examined. PMID:379210

Monitoring Potential Transport of Radioactive Contaminants in Shallow Ephemeral Channels: FY2013 and FY2014 (revised)

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

Mizell, Steve A.; Miller, Julianne J.; McCurdy, Greg D.

The Desert Research Institute (DRI) is conducting a field assessment of the potential for contaminated soil to be transported from the Smoky Contamination Area (CA) as a result of storm runoff, which supports National Nuclear Security Administration (NNSA) efforts to complete regulatory closure of the Soils Corrective Action Unit (CAU) contamination areas. The work is intended to confirm the likely mechanism of transport and determine the meteorological conditions that might cause movement of contaminated soils, as well as determine the particle size fraction that is most closely associated with transported radionuclide-contaminated soils. These data will facilitate the appropriate closure designmore » and post-closure monitoring program.« less

Analysis and Comparison of Aluminum Alloy Welded Joints Between Metal Inert Gas Welding and Tungsten Inert Gas Welding

NASA Astrophysics Data System (ADS)

Zhao, Lei; Guan, Yingchun; Wang, Qiang; Cong, Baoqiang; Qi, Bojin

2015-09-01

Surface contamination usually occurs during welding processing and it affects the welds quality largely. However, the formation of such contaminants has seldom been studied. Effort was made to study the contaminants caused by metal inert gas (MIG) welding and tungsten inert gas (TIG) welding processes of aluminum alloy, respectively. SEM, FTIR and XPS analysis was carried out to investigate the microstructure as well as surface chemistry. These contaminants were found to be mainly consisting of Al2O3, MgO, carbide and chromium complexes. The difference of contaminants between MIG and TIG welds was further examined. In addition, method to minimize these contaminants was proposed.

Metabolomics reveals mycoplasma contamination interferes with the metabolism of PANC-1 cells.

PubMed

Yu, Tao; Wang, Yongtao; Zhang, Huizhen; Johnson, Caroline H; Jiang, Yiming; Li, Xiangjun; Wu, Zeming; Liu, Tian; Krausz, Kristopher W; Yu, Aiming; Gonzalez, Frank J; Huang, Min; Bi, Huichang

2016-06-01

Mycoplasma contamination is a common problem in cell culture and can alter cellular functions. Since cell metabolism is either directly or indirectly involved in every aspect of cell function, it is important to detect changes to the cellular metabolome after mycoplasma infection. In this study, liquid chromatography mass spectrometry (LC/MS)-based metabolomics was used to investigate the effect of mycoplasma contamination on the cellular metabolism of human pancreatic carcinoma cells (PANC-1). Multivariate analysis demonstrated that mycoplasma contamination induced significant metabolic changes in PANC-1 cells. Twenty-three metabolites were identified and found to be involved in arginine and purine metabolism and energy supply. This study demonstrates that mycoplasma contamination significantly alters cellular metabolite levels, confirming the compelling need for routine checking of cell cultures for mycoplasma contamination, particularly when used for metabolomics studies. Graphical abstract Metabolomics reveals mycoplasma contamination changes the metabolome of PANC-1 cells.

Contaminant Interferences with SIMS Analyses of Microparticle Impactor Residues on LDEF Surfaces

NASA Technical Reports Server (NTRS)

Simon, C. G.; Batchelor, D.; Griffis, D. P.; Hunter, J. L.; Misra, V.; Ricks, D. A.; Wortman, J. J.

1992-01-01

Elemental analyses of impactor residues on high purity surface exposed to the low earth orbit (LEO) environment for 5.8 years on Long Duration Exposure Facility (LDEF) has revealed several probable sources for microparticles at this altitude, including natural micrometeorites and manmade debris ranging from paint pigments to bits of stainless steel. A myriad of contamination interferences were identified and their effects on impactor debris identification mitigated during the course of this study. These interferences included pre-, post-, and in-flight deposited particulate surface contaminants, as well as indigenous heterogeneous material contaminants. Non-flight contaminants traced to human origins, including spittle and skin oils, contributed significant levels of alkali-rich carbonaceous interferences. A ubiquitous layer of in-flight deposited silicaceous contamination varied in thickness with location on LDEF and proximity to active electrical fields. In-flight deposited (low velocity) contaminants included urine droplets and bits of metal film from eroded thermal blankets.

Evaluation of a cleanser for petroleum-contaminated skin.

PubMed

Phieffer, Laura S; Banks, David M; Bosse, Michael J; Meyer, Martha H; Meyer, Ralph A; Smith, Kevin

2003-12-01

Extremity injuries contaminated with petroleum products pose clinical dilemmas. This project was designed to evaluate the efficacy of a dioctyl sulfosuccinate (DS) solution for cleansing petroleum-contaminated skin. One hundred Sprague-Dawley rats were subjected to a contamination protocol followed by a cleansing procedure. Four petroleum contaminants and five cleansing solutions were selected. The protocol consisted of shaving, initial punch biopsy, contamination, precleansing punch biopsy, standardized scrub protocol, and postcleansing punch biopsy. Biopsy samples were analyzed for petroleum residue using fluorometry. The 10% DS solution had the highest reduction of crude oil, grease, and tar: 99.6 +/- 0.4% (mean +/- SD) contaminant reduction for crude oil, 99.8 +/- 0.2% for grease, and 99.8 +/- 0.2% for tar. The other cleansers showed less efficacy (p < 0.05). Concentrated DS appears to be significantly more effective at cleaning petroleum products from skin than the commonly chosen surgical and commercial cleansers.

Leak Rate Performance of Silicone Elastomer O-Rings Contaminated with JSC-1A Lunar Regolith Simulant

NASA Technical Reports Server (NTRS)

Oravec, Heather Ann; Daniels, Christopher C.

2014-01-01

Contamination of spacecraft components with planetary and foreign object debris is a growing concern. Face seals separating the spacecraft cabin from the debris filled environment are particularly susceptible; if the seal becomes contaminated there is potential for decreased performance, mission failure, or catastrophe. In this study, silicone elastomer O-rings were contaminated with JSC- 1A lunar regolith and their leak rate performance was evaluated. The leak rate values of contaminated O-rings at four levels of seal compression were compared to those of as-received, uncontaminated, O-rings. The results showed a drastic increase in leak rate after contamination. JSC-1A contaminated O-rings lead to immeasurably high leak rate values for all levels of compression except complete closure. Additionally, a mechanical method of simulant removal was examined. In general, this method returned the leak rate to as-received values.

Contamination analysis unit

DOEpatents

Gregg, H.R.; Meltzer, M.P.

1996-05-28

The portable Contamination Analysis Unit (CAU) measures trace quantities of surface contamination in real time. The detector head of the portable contamination analysis unit has an opening with an O-ring seal, one or more vacuum valves and a small mass spectrometer. With the valve closed, the mass spectrometer is evacuated with one or more pumps. The O-ring seal is placed against a surface to be tested and the vacuum valve is opened. Data is collected from the mass spectrometer and a portable computer provides contamination analysis. The CAU can be used to decontaminate and decommission hazardous and radioactive surfaces by measuring residual hazardous surface contamination, such as tritium and trace organics. It provides surface contamination data for research and development applications as well as real-time process control feedback for industrial cleaning operations and can be used to determine the readiness of a surface to accept bonding or coatings. 1 fig.

Contamination analysis unit

DOEpatents

Gregg, Hugh R.; Meltzer, Michael P.

1996-01-01

The portable Contamination Analysis Unit (CAU) measures trace quantifies of surface contamination in real time. The detector head of the portable contamination analysis unit has an opening with an O-ring seal, one or more vacuum valves and a small mass spectrometer. With the valve closed, the mass spectrometer is evacuated with one or more pumps. The O-ring seal is placed against a surface to be tested and the vacuum valve is opened. Data is collected from the mass spectrometer and a portable computer provides contamination analysis. The CAU can be used to decontaminate and decommission hazardous and radioactive surface by measuring residual hazardous surface contamination, such as tritium and trace organics It provides surface contamination data for research and development applications as well as real-time process control feedback for industrial cleaning operations and can be used to determine the readiness of a surface to accept bonding or coatings.

Disgust as a Unique Affective Predictor of Mental Contamination Following Sexual Trauma

PubMed Central

Badour, Christal L.; Ojserkis, Rachel; McKay, Dean; Feldner, Matthew T.

2014-01-01

Mental contamination has been described as an internal experience of dirtiness that can arise and persist in the absence of contact with observable physical contaminants. Recent research has examined mental contamination specifically related to unwanted physical contact and sexual trauma. This study evaluated the degree to which disgust propensity and both self-focused and perpetrator-focused peritraumatic disgust were associated with mental contamination in a sample of women who experienced sexual trauma (n = 72). Results showed that peritraumatic self-focused disgust, but not peritraumatic perpetrator-focused disgust or fear, was significantly associated with mental contamination. Additionally, disgust propensity contributed significantly to the incremental validity of the model. These findings support the nascent literature showing that disgust plays a significant role in mental contamination, particularly following sexual trauma. Future research directions, and clinical/theoretical implications of these results are discussed. PMID:25129888

STS-1 mission contamination evaluation approach

NASA Technical Reports Server (NTRS)

Jacobs, S.; Ehlers, H.; Miller, E. R.

1980-01-01

The space transportation system 1 mission will be the first opportunity to assess the induced environment of the orbiter payload bay region. Two tools were developed to aid in this assessment. The shuttle payload contamination evaluation computer program was developed to provide an analytical tool for prediction of the induced molecular contamination environment of the space shuttle orbiter during its onorbit operations. An induced environment contamination monitor was constructed and tested to measure the space shuttle orbiter contamination environment inside the payload bay during ascent and descent and inside and outside the payload bay during the onorbit phase. Measurements are to be performed during the four orbital flight test series. Measurements planned for the first flight are described and predicted environmental data are discussed. The results indicate that the expected data are within the measurement range of the induced environment contamination monitor instruments evaluated, and therefore it is expected that useful contamination environmental data will be available after the first flight.

Migration and generation of contaminants from launch through recovery: LDEF case history

NASA Technical Reports Server (NTRS)

Crutcher, E. R.; Nishimura, L. S.; Warner, K. J.; Wascher, W. W.

1992-01-01

It is possible to recreate the contamination history of the Long Duration Exposure Facility (LDEF) through an analysis of its contaminants and selective samples that were collected from surfaces with better documented exposure histories. This data was then used to compare estimates based on monitoring methods that were selected for the purpose of tracking LDEF's exposure to contaminants. The LDEF experienced much more contamination than would have been assumed based on the monitors. Work is still in progress but much of what was learned so far is already being used in the selection of materials and in the design of systems for space. Now experiments are being prepared for flight to resolve questions created by the discoveries on the LDEF. A summary of what was learned about LDEF contaminants over the first year since recovery and deintegration is presented. Over 35 specific conclusions in 5 contamination related categories are listed.

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.

Polyhexamethyl biguanide can eliminate contaminant yeasts from fuel-ethanol fermentation process.

PubMed

Elsztein, Carolina; de Menezes, João Assis Scavuzzi; de Morais, Marcos Antonio

2008-09-01

Industrial ethanol fermentation is a non-sterile process and contaminant microorganisms can lead to a decrease in industrial productivity and significant economic loss. Nowadays, some distilleries in Northeastern Brazil deal with bacterial contamination by decreasing must pH and adding bactericides. Alternatively, contamination can be challenged by adding a pure batch of Saccharomyces cerevisiae-a time-consuming and costly process. A better strategy might involve the development of a fungicide that kills contaminant yeasts while preserving S. cerevisiae cells. Here, we show that polyhexamethyl biguanide (PHMB) inhibits and kills the most important contaminant yeasts detected in the distilleries of Northeastern Brazil without affecting the cell viability and fermentation capacity of S. cerevisiae. Moreover, some physiological data suggest that PHMB acts through interaction with the yeast membrane. These results support the development of a new strategy for controlling contaminant yeast population whilst keeping industrial yields high.

Public health assessment for Petro-Chemical, Inc. (Turtle Bayou) Liberty, Liberty County, Texas, Region 6. CERCLIS No. TXD980873350. Final report

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

Not Available

1993-03-30

The Petro-Chemical Systems, Inc. site, located near Liberty, Texas, is a site where unauthorized disposal of petroleum-based oils has taken place. Although there is evidence of past exposure to site contaminants, the best available evidence does not indicate that humans are currently being exposed to site contaminants at levels that could cause adverse health effects. Contaminated ground water, surface water, soils, and surface water sediments have been found on the site. Although sampling was done for 144 priority pollutants, the primary contaminants of concern are benzene, ethylbenzene, xylene, naphthalene, polycyclic aromatic hydrocarbons, and lead. Because the greatest threat to publicmore » health would be contamination of drinking water, the Agency for Toxic Substances and Disease Registry (ATSDR) has recommended that necessary actions are taken to insure that private wells do not become contaminated with site contaminants.« less

Contamination of water resources by pathogenic bacteria

PubMed Central

2014-01-01

Water-borne pathogen contamination in water resources and related diseases are a major water quality concern throughout the world. Increasing interest in controlling water-borne pathogens in water resources evidenced by a large number of recent publications clearly attests to the need for studies that synthesize knowledge from multiple fields covering comparative aspects of pathogen contamination, and unify them in a single place in order to present and address the problem as a whole. Providing a broader perceptive of pathogen contamination in freshwater (rivers, lakes, reservoirs, groundwater) and saline water (estuaries and coastal waters) resources, this review paper attempts to develop the first comprehensive single source of existing information on pathogen contamination in multiple types of water resources. In addition, a comprehensive discussion describes the challenges associated with using indicator organisms. Potential impacts of water resources development on pathogen contamination as well as challenges that lie ahead for addressing pathogen contamination are also discussed. PMID:25006540

Public health assessment for USMC Marine Corps Recruit Depot (a/k/a Parris Island Marine Corps Recruit Depot), Parris Island, Beaufort County, South Carolina, Region 4. Cerclis No. SC6170022762

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

NONE

1996-09-12

Marine Corps Recruit Depot, (MCRD) Parris Island was proposed for listing on U.S. Environmental Protection Agency`s National Priorities List in August 1994. We identified two areas where chemical contaminants in soil entered the surface water wetland areas and bioaccumulated in edible fish and shellfish species: (1) contaminated fish and shellfish at the Causeway Landfill (Site 3) and (2) contaminated shellfish near the Rifle Range. These exposure situations pose no apparent public health hazard due to the low levels of contaminants detected in fish and shellfish. However, because the landfill has no impermeable cap nor leachate collection system, it is notmore » known whether contaminants in fish and shellfish will increase over time. The remaining 57 contaminated areas pose no public health hazard because people are not coming in contact with contaminants.« less

Process Upsets Involving Trace Contaminant Control Systems

NASA Technical Reports Server (NTRS)

Graf, John C.; Perry, Jay; Wright, John; Bahr, Jim

2000-01-01

Paradoxically, trace contaminant control systems that suffer unexpected upsets and malfunctions can release hazardous gaseous contaminants into a spacecraft cabin atmosphere causing potentially serious toxicological problems. Trace contaminant control systems designed for spaceflight typically employ a combination of adsorption beds and catalytic oxidation reactors to remove organic and inorganic trace contaminants from the cabin atmosphere. Interestingly, the same design features and attributes which make these systems so effective for purifying a spacecraft's atmosphere can also make them susceptible to system upsets. Cabin conditions can be contributing causes of phenomena such as adsorbent "rollover" and catalyst poisoning can alter a systems performance and in some in stances release contamination into the cabin. Evidence of these phenomena has been observed both in flight and during ground-based tests. The following discussion describes specific instances of system upsets found in trace contaminant control systems, groups these specific upsets into general hazard classifications, and recommends ways to minimize these hazards.

Towards a better control of optics cleanliness

NASA Astrophysics Data System (ADS)

Berlioz, P.

2017-11-01

The contamination of optics can considerably degrade the transmission and scattering of spacecraft optics. To prevent efficiently optics from contamination involves introducing since design phase requirements on materials and protections (covers…). Then, integration and test phase demands to implement heavy and stringent means (clean room, specific garment, covers…) and a permanent monitoring by fine contamination measurement of instrument environment and surfaces. Contamination budgets are drawn the project along, first prediction budgets based on analysis and potentially modeling, during design phase, then actual budgets based on contamination measurement during integration and test phase. Finally, the risk still exists to have to clean optics because of hazardous contamination, furthermore to dismount them. The cleanliness engineering set at ASTRIUM Toulouse is presented here, including the contamination monitoring via witness samples measured by IR spectrometry and via counters. ASTRIUM is presently focusing attention on no contact cleaning like the promising UV-ozone process.

Public health assessment for El Toro Marine Corps Air Station, Santa Ana, Orange County, California, Region 9. CERCLIS No. CA6170023208. Final report

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

Not Available

El Toro Marine Corps Air Station is in Orange County, California, near the city of Irvine. The Marine Corps established El Toro in 1943, and it currently serves as the center for marine aviation operations on the Pacific Coast. El Toro Marine Corps Air Station was proposed for listing on EPA's National Priorities List (NPL) in 1989 because past operations and disposal practices contaminated local groundwater. Agricultural farm workers and well operators are exposed to contaminants in groundwater through unintentional ingestion of contaminated groundwater, dermal contact with contaminated groundwater, and inhalation of aerosolized groundwater contaminants. Future exposure could occur throughmore » two potable water wells that are located 10 miles downgradient of the contaminant plume. At the current rate of contaminant migration, those wells will be affected in one and a half to five years.« less

Bacteriological evaluation of a new air turbine handpiece for preventing cross-contamination in dental procedures.

PubMed

Masuda, K; Ohta, M; Ohsuka, S; Matsuyama, M; Ashoori, M; Usami, T; Ito, M; Ueda, M; Kaneda, T

1994-03-01

An autoclavable air turbine handpiece, Air Flushing Clean System (AFCS) (Osada Electric Co., Ltd., Tokyo, Japan) was developed for use in dentistry with the objective of reducing cross-contamination. Its potential for bacterial contamination was investigated in vitro using two bacterial strains (Streptococcus mutants ATCC 25175 and Staphylococcus aureus FDA 209 P). In theory, this device should prevent cross-contamination of the internal water and air lines of the handpiece, by maintaining an internal positive pressure even after the turbine is stopped. In the present study, this AFCS device was found to reduce the bacterial contamination within the air turbine handpiece more effectively than the conventional handpiece used according to accepted protocol. The reduction of such contamination by the AFCS is in keeping with the recent objective of the American Dental Association to reduce cross-contamination during dental procedures.

In-situ remediation system and method for contaminated groundwater

DOEpatents

Corey, John C.; Looney, Brian B.; Kaback, Dawn S.

1989-01-01

A system for removing volatile contaminants from a subsurface plume of contamination comprising two sets of wells, a well for injecting a fluid into a saturated zone on one side of the plume and an extracting well for collecting the fluid together with volatilized contaminants from the plume on the other side of the plume. The fluid enables the volatile contaminants to be volatilized and carried therewith through the ground to the extracting well. Injecting and extracting wells are preferably horizontal wells positioned below the plume in the saturated zone and above the plume in the vadose zone, respectively. The fluid may be air or other gas or a gas and liquid mixture depending on the type of contaminant to be removed and may be preheated to facilitate volatilization. Treatment of the volatilized contamination may be by filtration, incineration, atmospheric dispersion or the like.

Bioremediation of contaminated groundwater

DOEpatents

Hazen, Terry C.; Fliermans, Carl B.

1995-01-01

An apparatus and method for in situ remediation of contaminated subsurface soil or groundwater contaminated by chlorinated hydrocarbons. A nutrient fluid is selected to stimulate the growth and reproduction of indigenous subsurface microorganisms that are capable of degrading the contaminants; an oxygenated fluid is selected to create a generally aerobic environment for these microorganisms to degrade the contaminants, leaving only pockets that are anaerobic. The nutrient fluid is injected periodically while the oxygenated fluid is injected continuously and both are extracted so that both are drawn across the plume. The nutrient fluid stimulates microbial colony growth; withholding it periodicially forces the larger, healthy colony of microbes to degrade the contaminants. Treatment is continued until the subsurface concentration of contaminants is reduced to an acceptable, preselected level. The nutrient fluid can be methane and the oxygenated fluid air for stimulating production of methanotrophs to break down chlorohydrocarbons, especially trichloroethylene (TCE) and tetrachloroethylene.

Bioremediation of contaminated groundwater

DOEpatents

Hazen, T.C.; Fliermans, C.B.

1995-01-24

An apparatus and method are described for in situ remediation of contaminated subsurface soil or groundwater contaminated by chlorinated hydrocarbons. A nutrient fluid is selected to stimulate the growth and reproduction of indigenous subsurface microorganisms that are capable of degrading the contaminants. An oxygenated fluid is selected to create a generally aerobic environment for these microorganisms to degrade the contaminants, leaving only pockets that are anaerobic. The nutrient fluid is injected periodically while the oxygenated fluid is injected continuously and both are extracted so that both are drawn across the plume. The nutrient fluid stimulates microbial colony growth. Withholding it periodically forces the larger, healthy colony of microbes to degrade the contaminants. Treatment is continued until the subsurface concentration of contaminants is reduced to an acceptable, preselected level. The nutrient fluid can be methane and the oxygenated fluid air for stimulating production of methanotrophs to break down chlorohydrocarbons, especially trichloroethylene (TCE) and tetrachloroethylene. 3 figures.

In-situ remediation system and method for contaminated groundwater

DOEpatents

Corey, J.C.; Looney, B.B.; Kaback, D.S.

1989-05-23

A system for removing volatile contaminants from a subsurface plume of contamination comprising two sets of wells, a well for injecting a fluid into a saturated zone on one side of the plume and an extracting well for collecting the fluid together with volatilized contaminants from the plume on the other side of the plume. The fluid enables the volatile contaminants to be volatilized and carried therewith through the ground to the extracting well. Injecting and extracting wells are preferably horizontal wells positioned below the plume in the saturated zone and above the plume in the vadose zone, respectively. The fluid may be air or other gas or a gas and liquid mixture depending on the type of contaminant to be removed and may be preheated to facilitate volatilization. Treatment of the volatilized contamination may be by filtration, incineration, atmospheric dispersion or the like. 3 figs.

Water Security Toolkit User Manual: Version 1.3 | Science ...

EPA Pesticide Factsheets

User manual: Data Product/Software The Water Security Toolkit (WST) is a suite of tools that help provide the information necessary to make good decisions resulting in the minimization of further human exposure to contaminants, and the maximization of the effectiveness of intervention strategies. WST assists in the evaluation of multiple response actions in order to select the most beneficial consequence management strategy. It includes hydraulic and water quality modeling software and optimization methodologies to identify: (1) sensor locations to detect contamination, (2) locations in the network in which the contamination was introduced, (3) hydrants to remove contaminated water from the distribution system, (4) locations in the network to inject decontamination agents to inactivate, remove or destroy contaminants, (5) locations in the network to take grab sample to confirm contamination or cleanup and (6) valves to close in order to isolate contaminated areas of the network.

Procedures involving lipid media for detection of bacterial contamination in breweries.

PubMed

Van Vuuren, H J; Louw, H A; Loos, M A; Meisel, R

1977-02-01

The liquid equivalent of universal beer agar, designated universal beer liquid medium, and its beer-free equivalent, universal liquid medium (UL), were equally effective in demonstrating bacterial contamination in 120 of 200 samples from different stages of commercial brewing process. Growth of the contaminants after 3 days was consistently more luxuriant in the UL medium. A yeast-water substrate medium failed to reveal many contaminants detected with UL in 392 samples from three breweries and revealed only a few not detected with UL. The use of UL and a lactose-peptone medium, with microscope examination of the media for bacterial growth, permitted detection of 93% of the known contaminants compared to 87%, detected with UL alone; this combination or universal beer liquid medium plus lactose-peptone medium can therefore be recommended for the detection of bacterial contaminants in brewery samples. Bacterial contamination of pitching yeasts appeared to be a particular problem in the breweries investigated.

Quantifying the dilution of the radiocesium contamination in Fukushima coastal river sediment (2011-2015)

NASA Astrophysics Data System (ADS)

Evrard, Olivier; Laceby, J. Patrick; Onda, Yuichi; Wakiyama, Yoshifumi; Jaegler, Hugo; Lefèvre, Irène

2016-10-01

Fallout from the Fukushima Dai-ichi nuclear power plant accident resulted in a 3000-km2 radioactive contamination plume. Here, we model the progressive dilution of the radiocesium contamination in 327 sediment samples from two neighboring catchments with different timing of soil decontamination. Overall, we demonstrate that there has been a ~90% decrease of the contribution of upstream contaminated soils to sediment transiting the coastal plains between 2012 (median - M - contribution of 73%, mean absolute deviation - MAD - of 27%) and 2015 (M 9%, MAD 6%). The occurrence of typhoons and the progress of decontamination in different tributaries of the Niida River resulted in temporary increases in local contamination. However, the much lower contribution of upstream contaminated soils to coastal plain sediment in November 2015 demonstrates that the source of the easily erodible, contaminated material has potentially been removed by decontamination, diluted by subsoils, or eroded and transported to the Pacific Ocean.

Correlation of in vitro challenge testing with consumer use testing for cosmetic products.

PubMed Central

Brannan, D K; Dille, J C; Kaufman, D J

1987-01-01

An in vitro microbial challenge test has been developed to predict the likelihood of consumer contamination of cosmetic products. The challenge test involved inoculating product at four concentrations (30, 50, 70, and 100%) with microorganisms known to contaminate cosmetics. Elimination of these microorganisms at each concentration was followed over a 28-day period. The test was used to classify products as poorly preserved, marginally preserved, or well preserved. Consumer use testing was then used to determine whether the test predicted the risk of actual consumer contamination. Products classified by the challenge test as poorly preserved returned 46 to 90% contaminated after use. Products classified by the challenge test as well preserved returned with no contamination. Marginally preserved products returned with 0 to 21% of the used units contaminated. As a result, the challenge test described can be accurately used to predict the risk of consumer contamination of cosmetic products. PMID:3662517

Adenovirus (For Parents)

MedlinePlus

... through respiratory secretions (coughs or sneezes) or fecal contamination. Fecal material can spread via contaminated water, eating food contaminated by houseflies, and poor hand washing (such ...

Metrics for Nitrate Contamination of Ground Water at CAFO Land Application Site - Arkansas Dairy Study

EPA Science Inventory

Nitrate is the most common chemical contaminant found in ground water. Recent research by U.S. EPA has shown that land application of manure can cause nitrate contamination of ground water above the maximum contaminant levels (MCLs) of 10 mg NO3-N/ L at significant depths. This...

Hyperspectral fluorescence imaging of animal feces and soil: potential use of fluorescence imaging for assessment of soil fecal contamination and compost maturity

USDA-ARS?s Scientific Manuscript database

Contamination by pathogenic microorganisms can lead to serious illnesses, particularly if thermal mishandling of contaminated agricultural produce occurs and promotes the incubation of potential pathogens. Pathogenic microbial contamination of agricultural products can occur through a variety of pat...

40 CFR 141.51 - Maximum contaminant level goals for inorganic contaminants.

Code of Federal Regulations, 2014 CFR

2014-07-01

... (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Maximum Contaminant Level...: Contaminant MCLG (mg/l) Antimony 0.006 Arsenic zero 1 Asbestos 7 Million fibers/liter (longer than 10 µm... Lead zero Mercury 0.002 Nitrate 10 (as Nitrogen). Nitrite 1 (as Nitrogen). Total Nitrate+Nitrite 10 (as...

40 CFR 141.51 - Maximum contaminant level goals for inorganic contaminants.

Code of Federal Regulations, 2012 CFR

2012-07-01

... (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Maximum Contaminant Level...: Contaminant MCLG (mg/l) Antimony 0.006 Arsenic zero 1 Asbestos 7 Million fibers/liter (longer than 10 µm... Lead zero Mercury 0.002 Nitrate 10 (as Nitrogen). Nitrite 1 (as Nitrogen). Total Nitrate+Nitrite 10 (as...

40 CFR 141.51 - Maximum contaminant level goals for inorganic contaminants.

Code of Federal Regulations, 2013 CFR

2013-07-01

... (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Maximum Contaminant Level...: Contaminant MCLG (mg/l) Antimony 0.006 Arsenic zero 1 Asbestos 7 Million fibers/liter (longer than 10 µm... Lead zero Mercury 0.002 Nitrate 10 (as Nitrogen). Nitrite 1 (as Nitrogen). Total Nitrate+Nitrite 10 (as...

Application of Passive Sampling for Measuring Dissolved Concentrations of Organic Contaminants in the Water Column at Three U.S. EPA Marine Superfund Sites

EPA Science Inventory

At contaminated sediment sites, including U.S. EPA Superfund sites, it is critical to measure water column concentrations of freely dissolved contaminants to understand the complete exposure of aquatic organisms to hydrophobic organic contaminants (HOCs). Historically acquiring ...

32 CFR 644.533 - Contamination discovered after return of land to owner, or sale.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 32 National Defense 4 2010-07-01 2010-07-01 true Contamination discovered after return of land to owner, or sale. 644.533 Section 644.533 National Defense Department of Defense (Continued) DEPARTMENT OF... Other Contamination from Proposed Excess Land and Improvements § 644.533 Contamination discovered after...

Application of Passive Sampling for Measuring Dissolved Concentrations of Organic Contaminants in the Water Column at Three U.S. EPA Marine Superfund Sites.

EPA Science Inventory

At contaminated sediment sites, including U.S. EPA Superfund sites, it is critical to measure water column concentrations of freely dissolved contaminants to understand the complete exposure of aquatic organisms to hydrophobic organic contaminants (HOCs). Historically, acquiring...

Evaluating Potential Human Health Risks Associated with the Development of Utility-Scale Solar Energy Facilities on Contaminated Sites

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

Cheng, J. -J.; Chang, Y. -S.; Hartmann, H.

2013-09-01

This report presents a general methodology for obtaining preliminary estimates of the potential human health risks associated with developing a utility-scale solar energy facility on a contaminated site, based on potential exposures to contaminants in soils (including transport of those contaminants into the air).

40 CFR 143.3 - Secondary maximum contaminant levels.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Secondary maximum contaminant levels... levels. The secondary maximum contaminant levels for public water systems are as follows: Contaminant Level Aluminum 0.05 to 0.2 mg/l. Chloride 250 mg/l. Color 15 color units. Copper 1.0 mg/l. Corrosivity...

The Western Airborne Contaminant Assessment Project (WACAP): An interdisciplinary evaluation of the impacts of airborne contaminants in Western U.S. National Parks

EPA Science Inventory

The Western Airborne Contaminants Assessment Project (WACAP) was initiated in 2002 by the National Park Service to determine if airborne contaminants were having an impact on remote western ecosystems. Multiple sample media (snow, water, sediment, fish and terrestrial vegetation...

Bioinspired Surface Treatments for Improved Decontamination: Commercial Products

DTIC Science & Technology

2017-07-28

simulants paraoxon, methyl salicylate, dimethyl methylphosphate, and diisopropyl fluorophosphates following treatment of contaminated surfaces with a...treatment of contaminated surfaces with a soapy water solution is reported along with droplet diffusion on the surfaces and wetting angles...Defense Program (CBDP) seeks to provide protection of forces in a contaminated environment including contamination avoidance, individual protection

Identifying fecal matter contamination in produce fields using multispectral reflectance imaging under ambient solar illumination

USDA-ARS?s Scientific Manuscript database

An imaging device to detect fecal contamination in fresh produce fields could allow the producer to avoid harvesting fecal-contaminated produce. E.coli O157:H7 outbreaks have been associated with fecal-contaminated leafy greens. In this study, in-field spectral profiles of bovine fecal matter, soil,...

UPTAKE AND DEPURATION OF NON-IONIC ORGANIC CONTAMINANTS FROM SEDIMENT BY THE OLIGOCHAETE, LUMBRICULUS VARIEGATUS

EPA Science Inventory

Uptake of sediment-associated contaminants by the oligochaete, Lumbriculus variegatus, was evaluated after 1,3,7,14,28, and 56 d of exposure to a field-collected sediment contaminated with DDT and its metabolites DDD and DDE or to a field-collected sediment contaminated with PAHs...

Laser cutting eliminates nucleic acid cross-contamination in dried-blood-spot processing.

PubMed

Murphy, Sean C; Daza, Glenda; Chang, Ming; Coombs, Robert

2012-12-01

Dried blood spots (DBS) are useful for molecular assays but are prone to false positives from cross-contamination. In our malaria DBS assay, cross-contamination was encountered despite cleaning techniques suitable for HIV-1. We therefore developed a contact-free laser cutting system that effectively eliminated cross-contamination during DBS processing.

[Viral contamination of polio vaccines in context of antivaccination mythology].

PubMed

Mats, A N; Kuz'mina, M N; Cheprasova, E V

2010-01-01

Analysis of publications about real and suggested contamination of polio vaccines produced in 1950s and 1960s with simian viruses--SV40 and SIV--is performed. Factual data are discussed and antivaccination fictions about calamitous consequences of really occurred contamination with SV40 and concocted contamination with SIV are refuted.

What research is happening to help prevent contamination of U.S. cotton?

USDA-ARS?s Scientific Manuscript database

U.S. cotton is considered to have some of the lowest levels of contamination in the world. However, that reputation is in jeopardy as complaints of contamination from domestic and foreign mills is on the rise. Cotton contamination can be classified under four major categorizes: fabrics and strings f...

Resolving Bacterial Contamination of Fuel Ethanol Fermentations with Beneficial Bacteria – an Alternative to Antibiotic Treatment

USDA-ARS?s Scientific Manuscript database

Fuel ethanol fermentations are not performed under aseptic conditions and microbial contamination reduces yields and can lead to costly “stuck fermentations.” Antibiotics are commonly used to combat contaminants, but these may persist in the distillers grains co-product. Among contaminants, it is kn...

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...

40 CFR 142.304 - For which of the regulatory requirements is a small system variance available?

Code of Federal Regulations, 2010 CFR

2010-07-01

... subpart for a national primary drinking water regulation for a microbial contaminant (including a bacterium, virus, or other organism) or an indicator or treatment technique for a microbial contaminant. (b... requirement specifying a maximum contaminant level or treatment technique for a contaminant with respect to...

In-situ remediation system for groundwater and soils

DOEpatents

Corey, John C.; Kaback, Dawn S.; Looney, Brian B.

1993-01-01

A method and system for in-situ remediation of contaminated groundwater and soil where the contaminants, such as toxic metals, are carried in a subsurface plume. The method comprises selection and injection into the soil of a fluid that will cause the contaminants to form stable, non-toxic compounds either directly by combining with the contaminants or indirectly by creating conditions in the soil or changing the conditions of the soil so that the formation of stable, non-toxic compounds between the contaminants and existing substances in the soil are more favorable. In the case of non-toxic metal contaminants, sulfides or sulfates are injected so that metal sulfides or sulfates are formed. Alternatively, an inert gas may be injected to stimulate microorganisms in the soil to produce sulfides which, in turn, react with the metal contaminants. Preferably, two wells are used, one to inject the fluid and one to extract the unused portion of the fluid. The two wells work in combination to create a flow of the fluid across the plume to achieve better, more rapid mixing of the fluid and the contaminants.

Trace chemical contaminant generation rates for spacecraft contamination control system design

NASA Technical Reports Server (NTRS)

Perry, J. L.

1995-01-01

A spacecraft presents a unique design challenge with respect to providing a comfortable environment in which people can live and work. All aspects of the spacecraft environmental design including the size of the habitable volume, its temperature, relative humidity, and composition must be considered to ensure the comfort and health of the occupants. The crew members and the materials selected for outfitting the spacecraft play an integral part in designing a habitable spacecraft because material offgassing and human metabolism are the primary sources for continuous trace chemical contaminant generation onboard a spacecraft. Since these contamination sources cannot be completely eliminated, active control processes must be designed and deployed onboard the spacecraft to ensure an acceptably clean cabin atmosphere. Knowledge of the expected rates at which contaminants are generated is very important to the design of these processes. Data from past spacecraft missions and human contaminant production studies have been analyzed to provide this knowledge. The resulting compilation of contaminants and generation rates serve as a firm basis for past, present, and future contamination control system designs for space and aeronautics applications.

Contamination of X-ray Cassettes with Methicillin-resistant Staphylococcus aureus and Methicillin-resistant Staphylococcus haemolyticus in a Radiology Department

PubMed Central

Kim, Han-Sung; Park, Ji-Young; Koo, Hyun-Sook; Choi, Chul-Sun; Song, Wonkeun; Cho, Hyoun Chan; Lee, Kyu Man

2012-01-01

Background We performed surveillance cultures of the surfaces of X-ray cassettes to assess contamination with methicillin-resistant Staphylococcus aureus (MRSA). Methods The surfaces of 37 X-ray cassettes stored in a radiology department were cultured using mannitol salt agar containing 6 µg/mL oxacillin. Suspected methicillin-resistant staphylococcal colonies were isolated and identified by biochemical testing. Pulsed-field gel electrophoresis (PFGE) analysis was performed to determine the clonal relationships of the contaminants. Results Six X-ray cassettes (16.2%) were contaminated with MRSA. During the isolation procedure, we also detected 19 X-ray cassettes (51.4%) contaminated with methicillin-resistant Staphylococcus haemolyticus (MRSH), identified as yellow colonies resembling MRSA on mannitol salt agar. PFGE analysis of the MRSA and MRSH isolates revealed that most isolates of each organism were identical or closely related to each other, suggesting a common source of contamination. Conclusions X-ray cassettes, which are commonly in direct contact with patients, were contaminated with MRSA and MRSH. In hospital environments, contaminated X-ray cassettes may serve as fomites for methicillin-resistant staphylococci. PMID:22563556

Contamination of X-ray cassettes with methicillin-resistant Staphylococcus aureus and methicillin-resistant Staphylococcus haemolyticus in a radiology department.

PubMed

Kim, Jae-Seok; Kim, Han-Sung; Park, Ji-Young; Koo, Hyun-Sook; Choi, Chul-Sun; Song, Wonkeun; Cho, Hyoun Chan; Lee, Kyu Man

2012-05-01

We performed surveillance cultures of the surfaces of X-ray cassettes to assess contamination with methicillin-resistant Staphylococcus aureus (MRSA). The surfaces of 37 X-ray cassettes stored in a radiology department were cultured using mannitol salt agar containing 6 µg/mL oxacillin. Suspected methicillin-resistant staphylococcal colonies were isolated and identified by biochemical testing. Pulsed-field gel electrophoresis (PFGE) analysis was performed to determine the clonal relationships of the contaminants. Six X-ray cassettes (16.2%) were contaminated with MRSA. During the isolation procedure, we also detected 19 X-ray cassettes (51.4%) contaminated with methicillin-resistant Staphylococcus haemolyticus (MRSH), identified as yellow colonies resembling MRSA on mannitol salt agar. PFGE analysis of the MRSA and MRSH isolates revealed that most isolates of each organism were identical or closely related to each other, suggesting a common source of contamination. X-ray cassettes, which are commonly in direct contact with patients, were contaminated with MRSA and MRSH. In hospital environments, contaminated X-ray cassettes may serve as fomites for methicillin-resistant staphylococci.

Perforation and bacterial contamination of microscope covers in lumbar spinal decompressive surgery.

PubMed

Osterhoff, Georg; Spirig, José; Klasen, Jürgen; Kuster, Stefan P; Zinkernagel, Annelies S; Sax, Hugo; Min, Kan

2014-01-01

To determine the integrity of microscope covers and bacterial contamination at the end of lumbar spinal decompressive surgery. A prospective study of 25 consecutive lumbar spinal decompressions with the use of a surgical microscope was performed. For detection of perforations, the microscope covers were filled with water at the end of surgery and the presence of water leakage in 3 zones (objective, ocular and control panel) was examined. For detection of bacterial contamination, swabs were taken from the covers at the same locations before and after surgery. Among the 25 covers, 1 (4%) perforation was observed and no association between perforation and bacterial contamination was seen; 3 (4%) of 75 smears from the 25 covers showed post-operative bacterial contamination, i.e. 2 in the ocular zone and 1 in the optical zone, without a cover perforation. The incidence of microscope cover perforation was very low and was not shown to be associated with bacterial contamination. External sources of bacterial contamination seem to outweigh the problem of contamination due to failure of cover integrity. © 2014 S. Karger AG, Basel.

Reclamation of petrol oil contaminated soil by rhamnolipids producing PGPR strains for growing Withania somnifera a medicinal shrub.

PubMed

Kumar, Rajesh; Das, Amar Jyoti; Juwarkar, Asha A

2015-02-01

Soil contaminated by hydrocarbons, cannot be used for agricultural intents due to their toxic effect to the plants. Surfactants producing by plant growth promotory rhizobacteria (PGPR) can effectively rig the problem of petroleum hydrocarbon contamination and growth promotion on such contaminated soils. In the present study three Pseudomonas strains isolated from contaminated soil identified by 16S rRNA analysis were ascertained for PGPR as well as biosurfactants property. Biosurfactants produced by the strains were further characterized and essayed for rhamnolipids. Inoculation of the strains in petrol hydrocarbon contaminated soil and its interaction with Withania somnifera in presence of petrol oil hydrocarbons depict that the strains helped in growth promotion of Withania somnifera in petrol oil contaminated soil while rhamnolipids helped in lowering the toxicity of petrol oil. The study was found to be beneficial as the growth and antioxidant activity of Withania sominfera was enhanced. Hence the present study signifies that rhamnolipids producing PGPR strains could be a better measure for reclamation of petrol contaminated sites for growing medicinal plants.

Occurrence of rhodamine B contamination in capsicum caused by agricultural materials during the vegetation process.

PubMed

Gao, Wei; Wu, Naiying; Du, Jingjing; Zhou, Li; Lian, Yunhe; Wang, Lei; Liu, Dengshuai

2016-08-15

This paper reports on the environmental rhodamine B (RhB) contamination in capsicum caused by agricultural materials during the vegetation process. Ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) was applied to detect 64 capsicum samples from China, Peru, India and Burma. Results demonstrated that RhB was found in all samples at low concentrations (0.11-0.98 μg/kg), indicating RhB contamination in capsicums is probably a ubiquitous phenomenon. In addition, studies into soils, roots, stems and leaves in Handan of Hebei province, China showed that the whole ecologic chain had been contaminated with RhB with the highest levels in leaves. The investigation into the agricultural environment in Handan of Hebei province and Korla of Xinjiang province, China demonstrated that the appearances of RhB contamination in the tested capsicums are mainly due to the agricultural materials contamination. The study verified that environmental contamination should be an important origin for the RhB contamination in capsicum fruits. Copyright © 2016 Elsevier Ltd. All rights reserved.

Extraction behavior of metallic contaminants and soil constituents from contaminated soils.

PubMed

Tokunaga, S; Park, S W; Ulmanu, M

2005-06-01

With an aim of developing an effective remediation technology for soils contaminated by heavy metals and metalloids, the extraction behavior of metallic contaminants as well as those of soil constituents was studied on a laboratory scale. Three contaminated soils collected from a former metal recycling plant were examined. These three soils were found to be contaminated by As, Cu, Pb, Sb, Se and Zn as compared to the non-contaminated soil. The pH-dependent extraction behavior of various elements from the soils was measured in a wide pH range and categorized into three groups. Hydrochloric acid (HCl), H2SO4, H3PO4, HNO3, sodium citrate, sodium tartrate, disodium dihydrogen ethylenediaminetetraacetate and diethylenetriaminepentaacetic acid were evaluated as extractants for removing contaminants from the soils. Extraction behavior of the soil constituents was also studied. The efficiency of the extraction was evaluated by the Japanese content and leaching tests. The stabilization of Pb remaining in the soil after the extraction process was conducted by the addition of iron(III) and calcium chloride.

Microbial Degradation of Petroleum Hydrocarbon Contaminants: An Overview

PubMed Central

Das, Nilanjana; Chandran, Preethy

2011-01-01

One of the major environmental problems today is hydrocarbon contamination resulting from the activities related to the petrochemical industry. Accidental releases of petroleum products are of particular concern in the environment. Hydrocarbon components have been known to belong to the family of carcinogens and neurotoxic organic pollutants. Currently accepted disposal methods of incineration or burial insecure landfills can become prohibitively expensive when amounts of contaminants are large. Mechanical and chemical methods generally used to remove hydrocarbons from contaminated sites have limited effectiveness and can be expensive. Bioremediation is the promising technology for the treatment of these contaminated sites since it is cost-effective and will lead to complete mineralization. Bioremediation functions basically on biodegradation, which may refer to complete mineralization of organic contaminants into carbon dioxide, water, inorganic compounds, and cell protein or transformation of complex organic contaminants to other simpler organic compounds by biological agents like microorganisms. Many indigenous microorganisms in water and soil are capable of degrading hydrocarbon contaminants. This paper presents an updated overview of petroleum hydrocarbon degradation by microorganisms under different ecosystems. PMID:21350672

Novel Laser Ablation Technology for Surface Decontamination

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

Cheng, Chung H.

2004-06-01

Laser ablation for surface cleaning has been pursued for the removal of paint on airplanes. It has also been pursued for the cleaning of semiconductor surfaces. However, all these approaches have been pursued by laser ablation in air. For highly contaminated surface, laser ablation in air can easily cause secondary contamination. Thus it is not suitable to apply to achieve surface decontamination for DOE facilities since many of these facilities have radioactive contaminants on the surface. Any secondary contamination will be a grave concern. The objective of this project is to develop a novel technology for laser ablation in liquidmore » for surface decontamination. It aims to achieve more efficient surface decontamination without secondary contamination and to evaluate the economic feasibility for large scale surface decontamination with laser ablation in liquid. When laser ablation is pursued in the solution, all the desorbed contaminants will be confined in liquid. The contaminants can be precipitated and subsequently contained in a small volume for disposal. It can reduce the risk of the decontamination workers. It can also reduce the volume of contaminants dramatically.« less

Assessment of microplastic-sorbed contaminant bioavailability through analysis of biomarker gene expression in larval zebrafish.

PubMed

Sleight, Victoria A; Bakir, Adil; Thompson, Richard C; Henry, Theodore B

2017-03-15

Microplastics (MPs) are prevalent in marine ecosystems. Because toxicants (termed here "co-contaminants") can sorb to MPs, there is potential for MPs to alter co-contaminant bioavailability. Our objective was to demonstrate sorption of two co-contaminants with different physicochemistries [phenanthrene (Phe), log 10 K ow =4.57; and 17α-ethinylestradiol (EE2), log 10 K ow =3.67] to MPs; and assess whether co-contaminant bioavailability was increased after MP settlement. Bioavailability was indicated by gene expression in larval zebrafish. Both Phe and EE2 sorbed to MPs, which reduced bioavailability by a maximum of 33% and 48% respectively. Sorption occurred, but was not consistent with predictions based on co-contaminant physicochemistry (Phe having higher log 10 K ow was expected to have higher sorption). Contaminated MPs settled to the bottom of the exposures did not lead to increased bioavailability of Phe or EE2. Phe was 48% more bioavailable than predicted by a linear sorption model, organism-based measurements therefore contribute unique insight into MP co-contaminant bioavailability. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Decontamination of uranium-contaminated waste oil using supercritical fluid and nitric acid.

PubMed

Sung, Jinhyun; Kim, Jungsoo; Lee, Youngbae; Seol, Jeunggun; Ryu, Jaebong; Park, Kwangheon

2011-07-01

The waste oil used in nuclear fuel processing is contaminated with uranium because of its contact with materials or environments containing uranium. Under current law, waste oil that has been contaminated with uranium is very difficult to dispose of at a radioactive waste disposal site. To dispose of the uranium-contaminated waste oil, the uranium was separated from the contaminated waste oil. Supercritical R-22 is an excellent solvent for extracting clean oil from uranium-contaminated waste oil. The critical temperature of R-22 is 96.15 °C and the critical pressure is 49.9 bar. In this study, a process to remove uranium from the uranium-contaminated waste oil using supercritical R-22 was developed. The waste oil has a small amount of additives containing N, S or P, such as amines, dithiocarbamates and dialkyldithiophosphates. It seems that these organic additives form uranium-combined compounds. For this reason, dissolution of uranium from the uranium-combined compounds using nitric acid was needed. The efficiency of the removal of uranium from the uranium-contaminated waste oil using supercritical R-22 extraction and nitric acid treatment was determined.

The effect of Piriformospora indica on the root development of maize (Zea mays L.) and remediation of petroleum contaminated soil.

PubMed

Zamani, Javad; Hajabbasi, Mohammad Ali; Alaie, Ebrahim; Sepehri, Mozhgan; Leuchtmann, Adrian; Schulin, Rainer

2016-01-01

As the depth of soil petroleum contamination can vary substantially under field conditions, a rhizotron experiment was performed to investigate the influence of endophyte, P. indica, on maize growth and degradation of petroleum components in a shallow and a deep-reaching subsurface layer of a soil. For control, a treatment without soil contamination was also included. The degree in contamination and the depth to which it extended had a strong effect on the growth of the plant roots. Contaminated soil layers severely inhibited root growth thus many roots preferred to bypass the shallow contaminated layer and grow in the uncontaminated soil. While the length and branching pattern of these roots were similar to those of uncontaminated treatment. Inoculation of maize with P. indica could improve root distribution and root and shoot growth in all three contamination treatments. This inoculation also enhanced petroleum degradation in soil, especially in the treatment with deep-reaching contamination, consequently the accumulation of petroleum hydrocarbons (PAHs) in the plant tissues were increased.

Assessment of contamination and misclassification biases in a randomized controlled trial of a social network peer education intervention to reduce HIV risk behaviors among drug users and risk partners in Philadelphia, PA and Chiang Mai, Thailand

PubMed Central

Simmons, Nicole; Donnell, Deborah; Ou, San-san; Celentano, David D.; Aramrattana, Apinun; Davis-Vogel, Annet; Metzger, David; Latkin, Carl

2015-01-01

Context Controlled trials of educational interventions are susceptible to contamination. Objectives To test a contamination measure based on recall of terms. Main study A randomized controlled trial of a social network peer education intervention among 1,123 injection drug users and risk partners in Philadelphia, PA and Chiang Mai, Thailand. Methods We assessed the recall of test, negative and positive control terms by intervention and control arm participants and compared the relative odds (OR) of recall of test vs. negative control terms between study arms. Results The contamination measure showed good discriminant ability only among participants from Chiang Mai. In Philadelphia there was no evidence of contamination and little evidence of diffusion. In Chiang Mai there was evidence of diffusion and contamination of 4 of 5 terms tested. Conclusions Network structure and peer education in Chiang Mai likely led to contamination. Recall of intervention materials can be a useful method to detect contamination in trials of educational interventions. PMID:25935214

In-situ remediation system for groundwater and soils

DOEpatents

Corey, J.C.; Kaback, D.S.; Looney, B.B.

1993-11-23

A method and system are presented for in-situ remediation of contaminated groundwater and soil where the contaminants, such as toxic metals, are carried in a subsurface plume. The method comprises selection and injection into the soil of a fluid that will cause the contaminants to form stable, non-toxic compounds either directly by combining with the contaminants or indirectly by creating conditions in the soil or changing the conditions of the soil so that the formation of stable, non-toxic compounds between the contaminants and existing substances in the soil are more favorable. In the case of non-toxic metal contaminants, sulfides or sulfates are injected so that metal sulfides or sulfates are formed. Alternatively, an inert gas may be injected to stimulate microorganisms in the soil to produce sulfides which, in turn, react with the metal contaminants. Preferably, two wells are used, one to inject the fluid and one to extract the unused portion of the fluid. The two wells work in combination to create a flow of the fluid across the plume to achieve better, more rapid mixing of the fluid and the contaminants. 4 figures.

Perforation and Bacterial Contamination of Microscope Covers in Lumbar Spinal Decompressive Surgery

PubMed Central

Osterhoff, Georg; Spirig, José; Klasen, Jürgen; Kuster, Stefan P.; Zinkernagel, Annelies S.; Sax, Hugo; Min, Kan

2014-01-01

Objective To determine the integrity of microscope covers and bacterial contamination at the end of lumbar spinal decompressive surgery. Materials and Methods A prospective study of 25 consecutive lumbar spinal decompressions with the use of a surgical microscope was performed. For detection of perforations, the microscope covers were filled with water at the end of surgery and the presence of water leakage in 3 zones (objective, ocular and control panel) was examined. For detection of bacterial contamination, swabs were taken from the covers at the same locations before and after surgery. Results Among the 25 covers, 1 (4%) perforation was observed and no association between perforation and bacterial contamination was seen; 3 (4%) of 75 smears from the 25 covers showed post-operative bacterial contamination, i.e. 2 in the ocular zone and 1 in the optical zone, without a cover perforation. Conclusions The incidence of microscope cover perforation was very low and was not shown to be associated with bacterial contamination. External sources of bacterial contamination seem to outweigh the problem of contamination due to failure of cover integrity. PMID:24903448

Microbial Contamination of Ice Machines Is Mediated by Activated Charcoal Filtration Systems in a City Hospital.

PubMed

Yorioka, Katsuhiro; Oie, Shigeharu; Hayashi, Koji; Kimoto, Hiroo; Furukawa, Hiroyuki

2016-06-01

Although microbial contamination of ice machines has been reported, no previous study has addressed microbial contamination of ice produced by machines equipped with activated charcoal (AC) filters in hospitals. The aim of this study was to provide clinical data for evaluating AC filters to prevent microbial contamination of ice. We compared microbial contamination in ice samples produced by machines with (n = 20) and without an AC filter (n = 40) in Shunan City Shinnanyo Municipal Hospital. All samples from the ice machine equipped with an AC filter contained 10-116 CFUs/g of glucose nonfermenting gram-negative bacteria such as Pseudomonas aeruginosa and Chryseobacterium meningosepticum. No microorganisms were detected in samples from ice machines without AC filters. After the AC filter was removed from the ice machine that tested positive for Gram-negative bacteria, the ice was resampled (n = 20). Analysis found no contaminants. Ice machines equipped with AC filters pose a serious risk factor for ice contamination. New filter-use guidelines and regulations on bacterial detection limits to prevent contamination of ice in healthcare facilities are necessary.

Biodegradation of chlorobenzene by indigenous bacteria

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

Nishino, S.F.; Spain, J.C.; Pettigrew, C.A.

Soil and ground water from four sites chronically contaminated with chlorobenzenes were examined to determine whether indigenous bacteria could degrade the contaminants and whether the addition of specific chlorobenzene-degrading bacteria enhanced the degradation rate. At each site, chlorobenzene-degrading bacteria were readily isolated from chlorobenzene-contaminated wells, whereas similar samples from noncontaminated wells yielded no chlorobenzene-degrading bacteria. Isolates were tested for growth on a variety of substrates. At a site contaminated with several solvents, a bioreactor was inoculated with the chlorobenzene-degrading Pseudomonas sp. strain JS150. Contaminated water was pumped through this bioreactor and a control bioreactor that had been colonized by inmore » indigenous microorganisms. The contaminants were removed from both bioreactors; however, JS150 could not be recovered from the inoculated bioreactor after three weeks of operation. A follow-up lab study using ground water from the contaminated site confirmed the field results. The authors conclude that chlorobenzene contamination of soil causes the development of indigenous degradative populations that have a competitive advantage over inoculated strains. The mechanism and time course of this acclimation are poorly understood and require additional study.« less

Green PCB Remediation from Sediment Systems (GPRSS) Project

NASA Technical Reports Server (NTRS)

Falker, John; Thompson, Karen; Zeitlin, Nancy; Quinn, Jacqueline; Parrish, Lewis M.

2014-01-01

An ongoing problem facing the global environment community including NASA centers is the removal and remediation of polychlorinated biphenyls (PCBs). PCBs were commonly used in a variety of materials including paints, caulking, and adhesives due to the advantageous physical and chemical properties that PCBs imparted to these various materials. Unfortunately, these properties have made the treatment of sites contaminated with these chemicals extremely difficult to deal with, due to their inherent chemical stability. The remediation of sediments contaminated with PCBs is especially difficult, primarily due to the risk of releasing the contaminant into the environment during the treatment process. Traditional treatment options involve the use of dredging and incineration of the contaminated soils/sediments, in which the chance of releasing the contaminants is greatly increased. The purpose of this project is to develop cleanup technology capable of remediating contaminated sediments in-situ, with minimum intrusion. This allows for the minimization of any potential contaminant release during the treatment process, providing a safer method for cleanup operations (as opposed to dredging/incineration) and still treating the basic problem of PCB contamination (as opposed to capping).

Evaluating Transport and Attenuation of Inorganic Contaminants in the Vadose Zone for Aqueous Waste Disposal Sites

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

Truex, Michael J.; Oostrom, Martinus; Tartakovsky, Guzel D.

An approach was developed for evaluating vadose zone transport and attenuation of aqueous wastes containing inorganic (non-volatile) contaminants that were disposed of at the land surface (i.e., directly to the ground in cribs, trenches, tile fields, etc.) and their effect on the underlying groundwater. The approach provides a structured method for estimating transport of contaminants through the vadose zone and the resulting temporal profile of groundwater contaminant concentrations. The intent of the approach is also to provide a means for presenting and explaining the results of the transport analysis in the context of the site-specific waste disposal conditions and sitemore » properties, including heterogeneities and other complexities. The document includes considerations related to identifying appropriate monitoring to verify the estimated contaminant transport and associated predictions of groundwater contaminant concentrations. While primarily intended for evaluating contaminant transport under natural attenuation conditions, the approach can also be applied to identify types of, and targets for, mitigation approaches in the vadose zone that would reduce the temporal profile of contaminant concentrations in groundwater, if needed.« less

Oxidative particle mixtures for groundwater treatment

DOEpatents

Siegrist, Robert L.; Murdoch, Lawrence C.

2000-01-01

The invention is a method and a composition of a mixture for degradation and immobilization of contaminants in soil and groundwater. The oxidative particle mixture and method includes providing a material having a minimal volume of free water, mixing at least one inorganic oxidative chemical in a granular form with a carrier fluid containing a fine grained inorganic hydrophilic compound and injecting the resulting mixture into the subsurface. The granular form of the inorganic oxidative chemical dissolves within the areas of injection, and the oxidative ions move by diffusion and/or advection, therefore extending the treatment zone over a wider area than the injection area. The organic contaminants in the soil and groundwater are degraded by the oxidative ions, which form solid byproducts that can sorb significant amounts of inorganic contaminants, metals, and radionuclides for in situ treatment and immobilization of contaminants. The method and composition of the oxidative particle mixture for long-term treatment and immobilization of contaminants in soil and groundwater provides for a reduction in toxicity of contaminants in a subsurface area of contamination without the need for continued injection of treatment material, or for movement of the contaminants, or without the need for continuous pumping of groundwater through the treatment zone, or removal of groundwater from the subsurface area of contamination.

Lead contamination of subarctic lakes and its response to reduced atmospheric fallout: can the recovery process be counteracted by the ongoing climate change?

PubMed

Klaminder, Jonatan; Hammarlund, Dan; Kokfelt, Ulla; Vonk, Jorien E; Bigler, Christian

2010-04-01

Can a climate-triggered export of old contaminants from the soil alter the lead (Pb) contaminant burden of subarctic lakes? To address this question, we reconstructed the pollution history of three high latitude lakes situated in a region where a recent climatic shift has occurred. Dated sediment records were used as archives of past Pb inputs to the lakes, where the difference in the (206)Pb/(207)Pb ratio between atmospheric contaminants ((206)Pb/(207)Pb ratio <1.16) and geogenic Pb in the catchment soil ((206)Pb/(207)Pb ratio >1.22) were used to trace fluxes of Pb contaminants. Lead contaminants were found in sediments deposited since Roman times. A significant export of Pb from the soil contaminant pool is indicated in two of the lakes surrounded by near-shore permafrost soils. Here, levels of Pb contaminants and (206)Pb/(207)Pb ratios of sediments deposited after the 1970s appear not to have been strongly affected by the >or=90% reduction in atmospheric deposition rates and increasing (206)Pb/(207)Pb ratios of atmospheric Pb since the 1990s. We concluded that soil processes stimulated by the ongoing climate change at high latitudes might work counteractive to efforts to reduce contaminant levels in subarctic lakes.

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.

Additional exposure of the Irish adult population to dioxins and PCBs from the diet as a consequence of the 2008 Irish dioxin food contamination incident.

PubMed

Tlustos, C; Anderson, W; Flynn, A; Pratt, I

2014-01-01

In 2008, the discovery of elevated levels of dioxins and PCBs in a porcine fat sample taken as part of the national residues monitoring programme led to the detection of a major feed contamination incidence in the Republic of Ireland. To estimate additional exposure to dioxins and PCBs due to the contamination incident, all data associated with the contamination incident were collected and reviewed. An exposure model was devised that took into account the proportion of contaminated product reaching the final consumer during the contamination incident window and which utilised all additional information that became available after the incident occurred. Exposure estimates derived for both dioxins and PCBs showed that the body burden of the general population remained largely unaffected by the contamination incident and only approximately 10% were exposed to elevated levels of dioxins and PCBs. Whilst this proportion of the population experienced quite a significant additional load to the existing body burden, the estimated exposure values do not suggest that these would be associated with adverse health effects, based on current knowledge. The exposure period was also limited in time to approximately 3 months, following the recall of contaminated meat immediately on detection of the contamination.

Bioremediation of a weathered and a recently oil-contaminated soils from Brazil: a comparison study.

PubMed

Trindade, P V O; Sobral, L G; Rizzo, A C L; Leite, S G F; Soriano, A U

2005-01-01

The facility with which hydrocarbons can be removed from soils varies inversely with aging of soil samples as a result of weathering. Weathering refers to the result of biological, chemical and physical processes that can affect the type of hydrocarbons that remain in a soil. These processes enhance the sorption of hydrophobic organic contaminants (HOCs) to the soil matrix, decreasing the rate and extent of biodegradation. Additionally, pollutant compounds in high concentrations can more easily affect the microbial population of a recently contaminated soil than in a weathered one, leading to inhibition of the biodegradation process. The present work aimed at comparing the biodegradation efficiencies obtained in a recently oil-contaminated soil (spiked one) from Brazil and an weathered one, contaminated for four years, after the application of bioaugmentation and biostimulation techniques. Both soils were contaminated with 5.4% of total petroleum hydrocarbons (TPHs) and the highest biodegradation efficiency (7.4%) was reached for the weathered contaminated soil. It could be concluded that the low biodegradation efficiencies reached for all conditions tested reflect the treatment difficulty of a weathered soil contaminated with a high crude oil concentration. Moreover, both soils (weathered and recently contaminated) submitted to bioaugmentation and biostimulation techniques presented biodegradation efficiencies approximately twice as higher as the ones without the aforementioned treatment (natural attenuation).

Monte Carlo simulation of the risk of contamination of apples with Escherichia coli O157:H7.

PubMed

Duffy, Siobain; Schaffner, Donald W

2002-10-25

Quantitative descriptions of the frequency and extent of contamination of apple cider with pathogenic bacteria were obtained using literature data and computer simulation. Probability distributions were chosen to describe the risk of apple contamination by each suspected pathway. Tree-picked apples may be contaminated by birds infected with Escherichia coli O157:H7 when orchards were located near a sewage source (ocean or landfill). Dropped apples could become contaminated from either infected animal droppings or from contaminated manure if used as fertilizer. A risk assessment model was created in Analytica. The results of worst-case simulations revealed that 6-9 log CFU E. coli O157:H7 might be found on a harvest of 1000 dropped apples, while 3-4 log CFU contamination could be present on 1000 tree-picked apples. This model confirms that practices such as using dropped apples and using animal waste as fertilizer increase risk in the production of apple cider, and that pasteurization may not eliminate all contamination in juice from heavily contaminated fruit. Recently published FDA regulations for juices requiring a 5-log CFU/ml reduction of pathogenic bacteria in fresh juices should be a fail-safe measure for apples harvested in all but the worst-case scenarios.

Evaluation of a Candidate Trace Contaminant Control Subsystem Architecture: The High Velocity, Low Aspect Ratio (HVLA) Adsorption Process

NASA Technical Reports Server (NTRS)

Kayatin, Matthew J.; Perry, Jay L.

2017-01-01

Traditional gas-phase trace contaminant control adsorption process flow is constrained as required to maintain high contaminant single-pass adsorption efficiency. Specifically, the bed superficial velocity is controlled to limit the adsorption mass-transfer zone length relative to the physical adsorption bed; this is aided by traditional high-aspect ratio bed design. Through operation in this manner, most contaminants, including those with relatively high potential energy are readily adsorbed. A consequence of this operational approach, however, is a limited available operational flow margin. By considering a paradigm shift in adsorption architecture design and operations, in which flows of high superficial velocity are treated by low-aspect ratio sorbent beds, the range of well-adsorbed contaminants becomes limited, but the process flow is increased such that contaminant leaks or emerging contaminants of interest may be effectively controlled. To this end, the high velocity, low aspect ratio (HVLA) adsorption process architecture was demonstrated against a trace contaminant load representative of the International Space Station atmosphere. Two HVLA concept packaging designs (linear flow and radial flow) were tested. The performance of each design was evaluated and compared against computer simulation. Utilizing the HVLA process, long and sustained control of heavy organic contaminants was demonstrated.

Genital region cleansing wipes: Effects on urine culture contamination.

PubMed

Selek, Mehmet Burak; Bektöre, Bayhan; Sezer, Ogün; Kula Atik, Tuğba; Baylan, Orhan; Özyurt, Mustafa

2017-01-30

Urine culture is the gold standard test for revealing the microbial agent causing urinary tract infection (UTI). Culture results are affected by sampling techniques; improper sampling leads to contamination of urine and thus contamination of the culture with urogenital flora. We aimed to evaluate the effect of urogenital cleansing, performed with chlorhexidine-containing genital region cleansing wipes (GRCW) on contamination rates. A total of 2,665 patients with UTI-related complaints and with urine culture requests from various outpatient clinics were enrolled in the study. Of the patients, 1,609 in the experimental group used GRCW before sampling, while 1,046 in the control group did not use any wipes. The contamination rate in the experimental group patients was 7.7%, while it was 15.8% in the control group. Contamination rates were significantly higher in the control group than in the experimental group for both women and men. Contamination rates for children and adults were also significantly lower in the experimental group than in the control group. Our study, conducted in a large population, showed that the use of chlorhexidine-containing cleansing wipes significantly reduced urine culture contamination rates in both genders, in both child and adult age groups. Using GRCW, collection of urine after urogenital area cleansing will decrease the contamination problem.

Patterns of cross-contamination in a multispecies population genomic project: detection, quantification, impact, and solutions.

PubMed

Ballenghien, Marion; Faivre, Nicolas; Galtier, Nicolas

2017-03-29

Contamination is a well-known but often neglected problem in molecular biology. Here, we investigated the prevalence of cross-contamination among 446 samples from 116 distinct species of animals, which were processed in the same laboratory and subjected to subcontracted transcriptome sequencing. Using cytochrome oxidase 1 as a barcode, we identified a minimum of 782 events of between-species contamination, with approximately 80% of our samples being affected. An analysis of laboratory metadata revealed a strong effect of the sequencing center: nearly all the detected events of between-species contamination involved species that were sent the same day to the same company. We introduce new methods to address the amount of within-species, between-individual contamination, and to correct for this problem when calling genotypes from base read counts. We report evidence for pervasive within-species contamination in this data set, and show that classical population genomic statistics, such as synonymous diversity, the ratio of non-synonymous to synonymous diversity, inbreeding coefficient F IT , and Tajima's D, are sensitive to this problem to various extents. Control analyses suggest that our published results are probably robust to the problem of contamination. Recommendations on how to prevent or avoid contamination in large-scale population genomics/molecular ecology are provided based on this analysis.

Microbial Functional Gene Diversity Predicts Groundwater Contamination and Ecosystem Functioning

PubMed Central

Zhang, Ping; Wu, Linwei; Rocha, Andrea M.; Shi, Zhou; Wu, Bo; Qin, Yujia; Wang, Jianjun; Yan, Qingyun; Curtis, Daniel; Ning, Daliang; Van Nostrand, Joy D.; Wu, Liyou; Watson, David B.; Adams, Michael W. W.; Alm, Eric J.; Adams, Paul D.; Arkin, Adam P.

2018-01-01

ABSTRACT Contamination from anthropogenic activities has significantly impacted Earth’s biosphere. However, knowledge about how environmental contamination affects the biodiversity of groundwater microbiomes and ecosystem functioning remains very limited. Here, we used a comprehensive functional gene array to analyze groundwater microbiomes from 69 wells at the Oak Ridge Field Research Center (Oak Ridge, TN), representing a wide pH range and uranium, nitrate, and other contaminants. We hypothesized that the functional diversity of groundwater microbiomes would decrease as environmental contamination (e.g., uranium or nitrate) increased or at low or high pH, while some specific populations capable of utilizing or resistant to those contaminants would increase, and thus, such key microbial functional genes and/or populations could be used to predict groundwater contamination and ecosystem functioning. Our results indicated that functional richness/diversity decreased as uranium (but not nitrate) increased in groundwater. In addition, about 5.9% of specific key functional populations targeted by a comprehensive functional gene array (GeoChip 5) increased significantly (P < 0.05) as uranium or nitrate increased, and their changes could be used to successfully predict uranium and nitrate contamination and ecosystem functioning. This study indicates great potential for using microbial functional genes to predict environmental contamination and ecosystem functioning. PMID:29463661

Detection of aflatoxin and surface mould contaminated figs by using Fourier transform near-infrared reflectance spectroscopy.

PubMed

Durmuş, Efkan; Güneş, Ali; Kalkan, Habil

2017-01-01

Aflatoxins are toxic metabolites that are mainly produced by members of the Aspergillus section Flavi on many agricultural products. Certain agricultural products such as figs are known to be high risk products for aflatoxin contamination. Aflatoxin contaminated figs may show a bright greenish yellow fluorescence (BGYF) under ultraviolet (UV) light at a wavelength of 365 nm. Traditionally, BGYF positive figs are manually selected by workers. However, manual selection depends on the expertise level of the workers and it may cause them skin-related health problems due to UV radiation. In this study, we propose a non-invasive approach to detect aflatoxin and surface mould contaminated figs by using Fourier transform near-infrared (FT-NIR) reflectance spectroscopy. A classification accuracy of 100% is achieved for classifying the figs into aflatoxin contaminated/uncontaminated and surface mould contaminated/uncontaminated categories. In addition, a strong correlation has been found between aflatoxin and surface mould. Combined with pattern classification methods, the NIR spectroscopy can be used to detect aflatoxin contaminated figs non-invasively. Furthermore, a positive correlation between surface mould and aflatoxin contamination leads to a promising alternative indicator for the detection of aflatoxin-contaminated figs. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Community-level physiological profiles of microorganisms inhabiting soil contaminated with heavy metals

NASA Astrophysics Data System (ADS)

Kuźniar, Agnieszka; Banach, Artur; Stępniewska, Zofia; Frąc, Magdalena; Oszust, Karolina; Gryta, Agata; Kłos, Marta; Wolińska, Agnieszka

2018-01-01

The aim of the study was to assess the differences in the bacterial community physiological profiles in soils contaminated with heavy metals versus soils without metal contaminations. The study's contaminated soil originated from the surrounding area of the Szopienice non-ferrous metal smelter (Silesia Region, Poland). The control was soil unexposed to heavy metals. Metal concentration was appraised by flame atomic absorption spectrometry, whereas the the community-level physiological profile was determined with the Biolog EcoPlatesTM system. The soil microbiological activity in both sites was also assessed via dehydrogenase activity. The mean concentrations of metals (Cd and Zn) in contaminated soil samples were in a range from 147.27 to 12265.42 mg kg-1, and the heavy metal contamination brought about a situation where dehydrogenase activity inhibition was observed mostly in the soil surface layers. Our results demonstrated that there is diversity in the physiological profiles of microorganisms inhabiting contaminated and colntrol soils; therefore, for assessment purposes, these were treated as two clusters. Cluster I included colntrol soil samples in which microbial communities utilised most of the available substrates. Cluster II incorporated contaminated soil samples in which a smaller number of the tested substrates was utilised by the contained microorganisms. The physiological profiles of micro-organisms inhabiting the contaminated and the colntrol soils are distinctly different.

Spatial and seasonal patterns in stream water contamination across mountainous watersheds: Linkage with landscape characteristics

NASA Astrophysics Data System (ADS)

Ai, L.; Shi, Z. H.; Yin, W.; Huang, X.

2015-04-01

Landscape characteristics are widely accepted as strongly influencing stream water quality in heterogeneous watersheds. Understanding the relationships between landscape and specific water contaminant can greatly improve the predictability of potential contamination and the assessment of contaminant export. In this work, we examined the combined effects of watershed complexity, in terms of land use and physiography, on specific water contaminant across watersheds close to the Danjiangkou Reservoir. The land use composition, land use pattern, morphometric variables and soil properties were calculated at the watershed scale and considered potential factors of influence. Due to high co-dependence of these watershed characteristics, partial least squares regression was used to elucidate the linkages between some specific water contaminants and the 16 selected watershed characteristic variables. Water contaminant maps revealed spatial and seasonal heterogeneity. The dissolved oxygen values in the dry season were higher than those in the wet season, whereas the other contaminant concentrations displayed the opposite trend. The studied watersheds which are influenced strongly by urbanization, showed higher levels of ammonia nitrogen, total phosphorus, potassium permanganate index and petroleum, and lower levels of dissolved oxygen. The urban land use, largest patch index and the hypsometric integral were the dominant factors affecting specific water contaminant.

Health Risk-Based Assessment and Management of Heavy Metals-Contaminated Soil Sites in Taiwan

PubMed Central

Lai, Hung-Yu; Hseu, Zeng-Yei; Chen, Ting-Chien; Chen, Bo-Ching; Guo, Horng-Yuh; Chen, Zueng-Sang

2010-01-01

Risk-based assessment is a way to evaluate the potential hazards of contaminated sites and is based on considering linkages between pollution sources, pathways, and receptors. These linkages can be broken by source reduction, pathway management, and modifying exposure of the receptors. In Taiwan, the Soil and Groundwater Pollution Remediation Act (SGWPR Act) uses one target regulation to evaluate the contamination status of soil and groundwater pollution. More than 600 sites contaminated with heavy metals (HMs) have been remediated and the costs of this process are always high. Besides using soil remediation techniques to remove contaminants from these sites, the selection of possible remediation methods to obtain rapid risk reduction is permissible and of increasing interest. This paper discusses previous soil remediation techniques applied to different sites in Taiwan and also clarified the differences of risk assessment before and after soil remediation obtained by applying different risk assessment models. This paper also includes many case studies on: (1) food safety risk assessment for brown rice growing in a HMs-contaminated site; (2) a tiered approach to health risk assessment for a contaminated site; (3) risk assessment for phytoremediation techniques applied in HMs-contaminated sites; and (4) soil remediation cost analysis for contaminated sites in Taiwan. PMID:21139851

Sustainable mineral resources management: from regional mineral resources exploration to spatial contamination risk assessment of mining

NASA Astrophysics Data System (ADS)

Jordan, Gyozo

2009-07-01

Wide-spread environmental contamination associated with historic mining in Europe has triggered social responses to improve related environmental legislation, the environmental assessment and management methods for the mining industry. Mining has some unique features such as natural background contamination associated with mineral deposits, industrial activities and contamination in the three-dimensional subsurface space, problem of long-term remediation after mine closure, problem of secondary contaminated areas around mine sites, land use conflicts and abandoned mines. These problems require special tools to address the complexity of the environmental problems of mining-related contamination. The objective of this paper is to show how regional mineral resources mapping has developed into the spatial contamination risk assessment of mining and how geological knowledge can be transferred to environmental assessment of mines. The paper provides a state-of-the-art review of the spatial mine inventory, hazard, impact and risk assessment and ranking methods developed by national and international efforts in Europe. It is concluded that geological knowledge on mineral resources exploration is essential and should be used for the environmental contamination assessment of mines. Also, sufficient methodological experience, knowledge and documented results are available, but harmonisation of these methods is still required for the efficient spatial environmental assessment of mine contamination.

Cyclodextrin-enhanced solubilization of organic contaminants with implications for aquifer remediation

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

McCray, J.E.; Boving, T.B.; Brusseau, M.L.

2000-12-31

Reagents that enhance the aqueous solubility of nonaqueous phase organic liquid (NAPL) contaminants are under investigation for use in enhanced subsurface remediation technologies. Cyclodextrin, a glucose-based molecule, is such a reagent. In this paper, laboratory experiments and numerical model simulations are used to evaluate and understand the potential remediation performance of cyclodextrin. Physical properties of cyclodextrin solutions such as density, viscosity, and NAPL-aqueous interfacial tension are measured. Their analysis indicates that no serious obstacles exist related to fluid properties that would prevent the use of cyclodextrin solutions for subsurface NAPL remediation. Cyclodextrin-enhanced solubilization for a large suite of typical groundmore » water contaminants is measured in the laboratory, and the results are related to the physiochemical properties of the organic compounds. The most-hydrophobic contaminants experience a larger relative solubility enhancement than the less-hydrophobic contaminants but have lower aqueous-phase apparent solubilities. Numerical model simulations of enhanced-solubilization flushing of NAPL-contaminated soil demonstrate that the more-hydrophilic compounds exhibit the greatest mass-removal relates due to their greater apparent solubilities, and thus are initially more effectively removed from soil by enhanced-solubilization-flushing reagents. However, the relatively more hydrophobic contaminants exhibit a greater improvement in contaminant mass-removal (compared with water flushing) than that exhibited for the relatively hydrophilic contaminants.« less

Phase I Flow and Transport Model Document for Corrective Action Unit 97: Yucca Flat/Climax Mine, Nevada National Security Site, Nye County, Nevada, Revision 1 with ROTCs 1 and 2

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

Andrews, Robert

The Underground Test Area (UGTA) Corrective Action Unit (CAU) 97, Yucca Flat/Climax Mine, in the northeast part of the Nevada National Security Site (NNSS) requires environmental corrective action activities to assess contamination resulting from underground nuclear testing. These activities are necessary to comply with the UGTA corrective action strategy (referred to as the UGTA strategy). The corrective action investigation phase of the UGTA strategy requires the development of groundwater flow and contaminant transport models whose purpose is to identify the lateral and vertical extent of contaminant migration over the next 1,000 years. In particular, the goal is to calculate themore » contaminant boundary, which is defined as a probabilistic model-forecast perimeter and a lower hydrostratigraphic unit (HSU) boundary that delineate the possible extent of radionuclide-contaminated groundwater from underground nuclear testing. Because of structural uncertainty in the contaminant boundary, a range of potential contaminant boundaries was forecast, resulting in an ensemble of contaminant boundaries. The contaminant boundary extent is determined by the volume of groundwater that has at least a 5 percent chance of exceeding the radiological standards of the Safe Drinking Water Act (SDWA) (CFR, 2012).« less

A logical starting point for developing priorities for lizard and snake ecotoxicology: a review of available data.

PubMed

Campbell, Kym Rouse; Campbell, Todd S

2002-05-01

Reptiles, specifically lizards and snakes, usually are excluded from environmental contamination studies and ecological risk assessments. This brief summary of available lizard and snake environmental contaminant data is presented to assist in the development of priorities for lizard and snake ecotoxicology. Most contaminant studies were not conducted recently, list animals found dead or dying after pesticide application, report residue concentrations after pesticide exposure, compare contaminant concentrations in animals from different areas, compare residue concentrations found in different tissues and organs, or compare changes in concentrations over time. The biological significance of the contaminant concentrations is rarely studied. A few recent studies, especially those conducted on modern pesticides, link the contaminant effects with exposure concentrations. Nondestructive sampling techniques for determining organic and inorganic contaminant concentrations in lizards and snakes recently have been developed. Studies that relate exposure, concentration, and effects of all types of environmental contaminants on lizards and snakes are needed. Because most lizards eat insects, studies on the exposure, effects, and accumulation of insecticides in lizards, and their predators, should be a top priority. Because all snakes are upper-trophic-level carnivores, studies on the accumulation and effects of contaminants that are known to bioaccumulate or biomagnify up the food chain should be the top priority.

Reproduction, embryonic development, and maternal transfer of contaminants in the amphibian Gastrophryne carolinensis.

PubMed

Hopkins, William Alexander; DuRant, Sarah Elizabeth; Staub, Brandon Patrick; Rowe, Christopher Lee; Jackson, Brian Phillip

2006-05-01

Although many amphibian populations around the world are declining at alarming rates, the cause of most declines remains unknown. Environmental contamination is one of several factors implicated in declines and may have particularly important effects on sensitive developmental stages. Despite the severe effects of maternal transfer of contaminants on early development in other vertebrate lineages, no studies have examined the effects of maternal transfer of contaminants on reproduction or development in amphibians. We examined maternal transfer of contaminants in eastern narrow-mouth toads (Gastrophryne carolinensis) collected from a reference site and near a coal-burning power plant. Adult toads inhabiting the industrial area transferred significant quantities of selenium and strontium to their eggs, but Se concentrations were most notable (up to 100 microg/g dry mass). Compared with the reference site, hatching success was reduced by 11% in clutches from the contaminated site. In surviving larvae, the frequency of developmental abnormalities and abnormal swimming was 55-58% higher in the contaminated site relative to the reference site. Craniofacial abnormalities were nearly an order of magnitude more prevalent in hatchlings from the contaminated site. When all developmental criteria were considered collectively, offspring from the contaminated site experienced 19% lower viability. Although there was no statistical relationship between the concentration of Se or Sr transferred to eggs and any measure of offspring viability, our study demonstrates that maternal transfer may be an important route of contaminant exposure in amphibians that has been overlooked.

Reproduction, Embryonic Development, and Maternal Transfer of Contaminants in the Amphibian Gastrophryne carolinensis

PubMed Central

Hopkins, William Alexander; DuRant, Sarah Elizabeth; Staub, Brandon Patrick; Rowe, Christopher Lee; Jackson, Brian Phillip

2006-01-01

Although many amphibian populations around the world are declining at alarming rates, the cause of most declines remains unknown. Environmental contamination is one of several factors implicated in declines and may have particularly important effects on sensitive developmental stages. Despite the severe effects of maternal transfer of contaminants on early development in other vertebrate lineages, no studies have examined the effects of maternal transfer of contaminants on reproduction or development in amphibians. We examined maternal transfer of contaminants in eastern narrow-mouth toads (Gastrophryne carolinensis) collected from a reference site and near a coal-burning power plant. Adult toads inhabiting the industrial area transferred significant quantities of selenium and strontium to their eggs, but Se concentrations were most notable (up to 100 μg/g dry mass). Compared with the reference site, hatching success was reduced by 11% in clutches from the contaminated site. In surviving larvae, the frequency of developmental abnormalities and abnormal swimming was 55–58% higher in the contaminated site relative to the reference site. Craniofacial abnormalities were nearly an order of magnitude more prevalent in hatchlings from the contaminated site. When all developmental criteria were considered collectively, offspring from the contaminated site experienced 19% lower viability. Although there was no statistical relationship between the concentration of Se or Sr transferred to eggs and any measure of offspring viability, our study demonstrates that maternal transfer may be an important route of contaminant exposure in amphibians that has been overlooked. PMID:16675417

Testing human hair for drugs of abuse. IV. Environmental cocaine contamination and washing effects.

PubMed

Wang, W L; Cone, E J

1995-01-05

Active cocaine use results in sequestration of parent drug in hair. In addition, hair has unique physicochemical properties that permit absorption of cocaine from the environment. When hair is tested for evidence of cocaine, it is important to consider whether the positive test resulted from active drug use or environmental contamination. In a series of laboratory experiments, it was found that exposure of 'cut' hair to cocaine vapor ('crack' smoke) and to aqueous solutions of cocaine hydrochloride resulted in significant contamination of hair samples. Similar results were obtained with two subjects who were exposed to cocaine vapor in an unventilated room. The amount of contamination adsorbed by hair depended upon both time and extent of exposure. Washing the hair samples with methanol removed > 70% of the cocaine contaminant after cocaine vapor exposure, but was less effective (< 50%) following contamination with aqueous cocaine. Shampoo treatment cycles (overnight soaking) progressively removed increasing amounts of cocaine from the contaminated hair, but residual cocaine remained after 10 cycles. Studies were also performed to determine the usefulness of benzoylecgonine as a marker of active cocaine administration. Small amounts of benzoylecgonine (ca. 1 ng/mg) were formed in hair as a result of environmental contamination with cocaine. Also, it was found that benzoylecgonine could be adsorbed from illicit cocaine contaminated with benzoylecgonine. It was concluded that positive hair test results should be interpreted cautiously due to the possibility of environmental contamination from cocaine and related constituents.

Geophysical and flow-weighted natural-contaminant characterization of three water-supply wells in New Hampshire

USGS Publications Warehouse

Mack, Thomas J.; Belaval, Marcel; Degnan, James R.; Roy, Stephen J.; Ayotte, Joseph D.

2011-01-01

The water-supply systems investigated were typical of small community water systems in New Hampshire where a water system may serve 100 connections or less. Each water system consisted of two wells, approximately 300 to 400 feet deep, in generally low-yielding (about 10 gallons per minute or less) crystalline bedrock. The wells were typically operated a few hours per day to fill a storage tank and had tens of feet of drawdown caused by the low well yields. The systems selected had contaminant concentrations slightly above MCL, or a low-level contamination. One of the water systems investigated had low-level (10 to 24 micrograms per liter) arsenic contamination, and two of the water systems had low-level uranium (30 to 40 micrograms per liter) contamination. The contaminant values were blended-water concentrations from the two wells in a system. Each water system had differences in contaminant concentrations between the two wells. In each case, the well with the greater concentration of the two was selected for investigation. In two of the three systems investigated, there was either not enough variation in the borehole contaminant concentration or not enough water-yielding fractures for borehole modifications to be a viable potential remedy to elevated contamination. However, borehole and contaminant conditions in one of the bedrock supply-well systems may be favorable to potential improvement of supplied water by borehole modification where selected fracture zones are sealed off from supplying water to the well.

Distribution and fate of legacy and emerging contaminants along the Adriatic Sea: A comparative study.

PubMed

Combi, Tatiane; Pintado-Herrera, Marina G; Lara-Martin, Pablo A; Miserocchi, Stefano; Langone, Leonardo; Guerra, Roberta

2016-11-01

The spatial distributions and fates of selected legacy and emerging compounds were investigated and compared in surface sediments sampled along the Adriatic mud-wedge and in deep-sea regions from the southern Adriatic basin. Results indicated that the concentrations of legacy contaminants (PAHs, PCBs and DDTs) and emerging contaminants (tonalide, galaxolide, EHMC, octocrylene, BP3 and NP) ranged from 0.1 to 572 ng g -1 and from

A Field Study of NMR Logging to Quantify Petroleum Contamination in Subsurface Sediments

NASA Astrophysics Data System (ADS)

Fay, E. L.; Knight, R. J.; Grunewald, E. D.

2016-12-01

Nuclear magnetic resonance (NMR) measurements are directly sensitive to hydrogen-bearing fluids including water and petroleum products. NMR logging tools can be used to detect and quantify petroleum hydrocarbon contamination in the sediments surrounding a well or borehole. An advantage of the NMR method is that data can be collected in both cased and uncased holes. In order to estimate the volume of in-situ hydrocarbon, there must be sufficient contrast between either the relaxation times (T2) or the diffusion coefficients (D) of water and the contaminant. In a field study conducted in Pine Ridge, South Dakota, NMR logging measurements were used to investigate an area of hydrocarbon contamination from leaking underground storage tanks. A contaminant sample recovered from a monitoring well at the site was found to be consistent with a mixture of gasoline and diesel fuel. NMR measurements were collected in two PVC-cased monitoring wells; D and T2 measurements were used together to detect and quantify contaminant in the sediments above and below the water table at both of the wells. While the contrast in D between the fluids was found to be inadequate for fluid typing, the T2 contrast between the contaminant and water in silt enabled the estimation of the water and contaminant volumes. This study shows that NMR logging can be used to detect and quantify in-situ contamination, but also highlights the importance of sediment and contaminant properties that lead to a sufficiently large contrast in T2 or D.

Listeria monocytogenes Growth Kinetics in Milkshakes Made from Naturally and Artificially Contaminated Ice Cream.

PubMed

Salazar, Joelle K; Bathija, Vriddi M; Carstens, Christina K; Narula, Sartaj S; Shazer, Arlette; Stewart, Diana; Tortorello, Mary Lou

2018-01-01

This study assessed the growth of Listeria monocytogenes in milkshakes made using the process-contaminated ice cream associated with a listeriosis outbreak in comparison to milkshakes made with artificially contaminated ice cream. For all temperatures, growth kinetics including growth rates, lag phases, maximum populations, and population increases were determined for the naturally and artificially derived contaminants at 5, 10, 15, and 25°C storage for 144 h. The artificially inoculated L. monocytogenes presented lower growth rates and shorter lag phases than the naturally contaminated populations at all temperatures except for 5°C, where the reverse was observed. At 25°C, lag phases of the naturally and artificially contaminated L. monocytogenes were 11.6 and 7.8 h, respectively. The highest increase in population was observed for the artificially inoculated pathogen at 15°C after 96 h (6.16 log CFU/mL) of storage. Growth models for both contamination states in milkshakes were determined. In addition, this study evaluated the antimicrobial effectiveness of flavoring agents, including strawberry, chocolate and mint, on the growth of the pathogen in milkshakes during 10°C storage. All flavor additions resulted in decreased growth rates of L. monocytogenes for both contamination states. The addition of chocolate and mint flavoring also resulted in significantly longer lag phases for both contamination states. This study provides insight into the differences in growth between naturally and artificially contaminated L. monocytogenes in a food product.

Listeria monocytogenes Growth Kinetics in Milkshakes Made from Naturally and Artificially Contaminated Ice Cream

PubMed Central

Salazar, Joelle K.; Bathija, Vriddi M.; Carstens, Christina K.; Narula, Sartaj S.; Shazer, Arlette; Stewart, Diana; Tortorello, Mary Lou

2018-01-01

This study assessed the growth of Listeria monocytogenes in milkshakes made using the process-contaminated ice cream associated with a listeriosis outbreak in comparison to milkshakes made with artificially contaminated ice cream. For all temperatures, growth kinetics including growth rates, lag phases, maximum populations, and population increases were determined for the naturally and artificially derived contaminants at 5, 10, 15, and 25°C storage for 144 h. The artificially inoculated L. monocytogenes presented lower growth rates and shorter lag phases than the naturally contaminated populations at all temperatures except for 5°C, where the reverse was observed. At 25°C, lag phases of the naturally and artificially contaminated L. monocytogenes were 11.6 and 7.8 h, respectively. The highest increase in population was observed for the artificially inoculated pathogen at 15°C after 96 h (6.16 log CFU/mL) of storage. Growth models for both contamination states in milkshakes were determined. In addition, this study evaluated the antimicrobial effectiveness of flavoring agents, including strawberry, chocolate and mint, on the growth of the pathogen in milkshakes during 10°C storage. All flavor additions resulted in decreased growth rates of L. monocytogenes for both contamination states. The addition of chocolate and mint flavoring also resulted in significantly longer lag phases for both contamination states. This study provides insight into the differences in growth between naturally and artificially contaminated L. monocytogenes in a food product. PMID:29416531

Quantifying Diffuse Contamination: Method and Application to Pb in Soil.

PubMed

Fabian, Karl; Reimann, Clemens; de Caritat, Patrice

2017-06-20

A new method for detecting and quantifying diffuse contamination at the continental to regional scale is based on the analysis of cumulative distribution functions (CDFs). It uses cumulative probability (CP) plots for spatially representative data sets, preferably containing >1000 determinations. Simulations demonstrate how different types of contamination influence elemental CDFs of different sample media. It is found that diffuse contamination is characterized by a distinctive shift of the low-concentration end of the distribution of the studied element in its CP plot. Diffuse contamination can be detected and quantified via either (1) comparing the distribution of the contaminating element to that of an element with a geochemically comparable behavior but no contamination source (e.g., Pb vs Rb), or (2) comparing the top soil distribution of an element to the distribution of the same element in subsoil samples from the same area, taking soil forming processes into consideration. Both procedures are demonstrated for geochemical soil data sets from Europe, Australia, and the U.S.A. Several different data sets from Europe deliver comparable results at different scales. Diffuse Pb contamination in surface soil is estimated to be <0.5 mg/kg for Australia, 1-3 mg/kg for Europe, and 1-2 mg/kg, or at least <5 mg/kg, for the U.S.A. The analysis presented here also allows recognition of local contamination sources and can be used to efficiently monitor diffuse contamination at the continental to regional scale.

Bacterial Contamination of Multi-dose Eye Drops at Ophthalmology Department, University of Gondar, Northwest Ethiopia.

PubMed

Tsegaw, Asegedech; Tsegaw, Asamere; Abula, Tefera; Assefa, Yared

2017-01-01

Ophthalmic solutions used for both diagnostic and therapeutic purposes were found to be contaminated with bacteria pathogens and caused serious ocular infections such as keratitis and endophthalmitis. The objective was to assess the magnitude and pattern of bacterial contamination of multi-dose ophthalmic medications and investigate the drug susceptibility pattern of the isolates in the Department of Ophthalmology at Gondar University Teaching Hospital. A total of 100 ophthalmic medications in-use by patients and eye-care workers have been taken and cultured for potential bacterial contamination in the Microbiology Department after 1 week and >1 week of use. The dropper tip and the residual eye medications were examined for contamination. The contaminating bacteria were identified using a standard procedure and drug susceptibility testing to selected antimicrobial agents was done. Eleven ophthalmic medications were contaminated by different bacterial species with a prevalence of 11%. Multi-use and longer duration of use of eye medications were associated with higher rate of contamination. The contamination level ranges from 0% for antibiotics, 20% for local anesthetics, and 40% for povidone iodine. Among bacteria identified, Staphylococcus aureus and coagulase-negative Staphylococcus species were resistant to methicillin while others were sensitive to the antibiotics tested. The prevalence of contamination was low, but methicillin-resistant Staphylococcus was a potential risk. It is recommended that the Department of Ophthalmology should design set of rules about duration of use and safe handling of ophthalmic medications by the staff and patients.

Mortality risk factor analysis in colonic perforation: would retroperitoneal contamination increase mortality in colonic perforation?

PubMed

Yoo, Ri Na; Kye, Bong-Hyeon; Kim, Gun; Kim, Hyung Jin; Cho, Hyeon-Min

2017-10-01

Colonic perforation is a lethal condition presenting high morbidity and mortality in spite of urgent surgical treatment. This study investigated the surgical outcome of patients with colonic perforation associated with retroperitoneal contamination. Retrospective analysis was performed for 30 patients diagnosed with colonic perforation caused by either inflammation or ischemia who underwent urgent surgical treatment in our facility from January 2005 to December 2014. Patient characteristics were analyzed to find risk factors correlated with increased postoperative mortality. Using the Physiological and Operative Severity Score for the Enumeration of Mortality and Morbidity (POSSUM) audit system, the mortality and morbidity rates were estimated to verify the surgical outcomes. Patients with retroperitoneal contamination, defined by the presence of retroperitoneal air in the preoperative abdominopelvic CT, were compared to those without retroperitoneal contamination. Eight out of 30 patients (26.7%) with colonic perforation had died after urgent surgical treatment. Factors associated with mortality included age, American Society of Anesthesiologists (ASA) physical status classification, and the ischemic cause of colonic perforation. Three out of 6 patients (50%) who presented retroperitoneal contamination were deceased. Although the patients with retroperitoneal contamination did not show significant increase in the mortality rate, they showed significantly higher ASA physical status classification than those without retroperitoneal contamination. The mortality rate predicted from Portsmouth POSSUM was higher in the patients with retroperitoneal contamination. Patients presenting colonic perforation along with retroperitoneal contamination demonstrated severe comorbidity. However, retroperitoneal contamination was not found to be correlated with the mortality rate.

An investigation into the bacterial contamination of goniolenses in use in clinical practice.

PubMed

Grundon, Rachael; Scurrell, Emma; Mould, John; Hayton-Lee, Emma; Heinrich, Christine

2017-12-18

Objectives To report the incidence and evaluate the clinical significance of goniolens bacterial contamination in clinical use in dogs with three different usage protocols and one with an added cleaning protocol. Animals Studied and Methods Three groups of twenty dogs undergoing gonioscopy at a private practice in the UK had the goniolenses swabbed for bacteriology culture and identification prior to placement on the cornea. Three protocols of lens use, with 2 different types of goniolens, were studied. One protocol was then repeated with 21 dogs with a lens cleaning protocol prior to storage. Results Low levels of bacterial contamination were found in all 3 initial groups (10-15%). No correlation was found between usage protocol used and rate of contamination and no correlation was found between length of storage between use and contamination. All bacteria cultured were considered naturally occurring commensals for the canine eye and environment. The group with a cleaning protocol had a 4.7% contamination rate. This was not statistically different from the non-cleaning groups. Conclusions The rate of bacterial contamination of goniolenses in clinical practice is low and the bacterial contaminants consist of commensal bacteria, unlikely to be of detriment to the eye. Minimal contamination of the goniolenses was found and this did not appear to be of clinical significance. The introduction of a simple cleaning protocol did not produce a statistically significant reduction in bacterial contamination. © 2017 American College of Veterinary Ophthalmologists.

The Effect of Airborne Contaminants on Fuel Cell Performance and Durability

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

St-Pierre, Jean; Pasaogullari, Ugur; Cheng, Tommy

The impact of contaminants on fuel cell performance was examined to document air filter specifications (prevention) and devise recovery procedures (maintenance) that are effective at the system level. Eight previously undocumented airborne contaminants were selected for detailed studies and characterization data was used to identify operating conditions that intensifying contamination effects. The use of many and complementary electrochemical, chemical and physical characterization methods and the derivation of several mathematical models supported the formulation of contamination mechanisms and the development of recovery procedures. The complexity of these contamination mechanisms suggests a shift to prevention and generic maintenance measures. Only two ofmore » the selected contaminants led to cell voltage losses after injection was interrupted. Proposed recovery procedures for calcium ions, a component of road de-icers, dessicants, fertilizers and soil conditioners, were either ineffective or partly effective, whereas for bromomethane, a fumigant, the cell voltage was recovered to its initial value before contamination by manipulating and sequencing operating conditions. However, implementation for a fuel cell stack and system remains to be demonstrated. Contamination mechanisms also led to the identification of membrane durability stressors. All 8 selected contaminants promote the formation of hydrogen peroxide, a known agent that can produce radicals that attack the ionomer and membrane molecular structure whereas the dehydrating effect of calcium ions on the ionomer and membrane increases their brittleness and favors the creation of pinholes under mechanical stresses. Data related to acetylene, acetonitrile and calcium ions are emphasized in the report.« less

Stochastic, compartmental, and dynamic modeling of cross-contamination during mechanical smearing of cheeses.

PubMed

Aziza, Fanny; Mettler, Eric; Daudin, Jean-Jacques; Sanaa, Moez

2006-06-01

Cheese smearing is a complex process and the potential for cross-contamination with pathogenic or undesirable microorganisms is critical. During ripening, cheeses are salted and washed with brine to develop flavor and remove molds that could develop on the surfaces. Considering the potential for cross-contamination of this process in quantitative risk assessments could contribute to a better understanding of this phenomenon and, eventually, improve its control. The purpose of this article is to model the cross-contamination of smear-ripened cheeses due to the smearing operation under industrial conditions. A compartmental, dynamic, and stochastic model is proposed for mechanical brush smearing. This model has been developed to describe the exchange of microorganisms between compartments. Based on the analytical solution of the model equations and on experimental data collected with an industrial smearing machine, we assessed the values of the transfer parameters of the model. Monte Carlo simulations, using the distributions of transfer parameters, provide the final number of contaminated products in a batch and their final level of contamination for a given scenario taking into account the initial number of contaminated cheeses of the batch and their contaminant load. Based on analytical results, the model provides indicators for smearing efficiency and propensity of the process for cross-contamination. Unlike traditional approaches in mechanistic models, our approach captures the variability and uncertainty inherent in the process and the experimental data. More generally, this model could represent a generic base to use in modeling similar processes prone to cross-contamination.

Effects of Hydrogeologic Conditions on Groundwater Contamination of CVOCs in the North Coast Karst Aquifer of Puerto Rico

NASA Astrophysics Data System (ADS)

Torres Torres, N. I.; Howard, J.; Padilla, I. Y.; Torres, P.; Cotto, I.; Irizarry, C.

2012-12-01

The karst system of northern Puerto Rico is the most productive aquifer of the island. It serves freshwater to industrial, domestic and agricultural purposes, and contributes to the ecological integrity of the region. The same characteristics that make this a highly productive aquifer, make it vulnerable to contamination of groundwater. Of particular importance is contamination with chlorinated volatile organic compounds (CVOCs), which have been related to preterm birth problems. A great extent of CVOC contamination has been seen in the North Coast of Puerto Rico since the 1970s. The main purposes of this study are (1) to relate the water quality of wells and springs with the hydrogeological conditions in the north coast limestone aquifer of Puerto Rico, and (2) to make a statistical analysis of the historical groundwater contamination in that area. To achieve these objectives, groundwater samples are collected from wells and springs during dry and wet seasons. Results show that trichloroethylene (TCE), tetrachloroethylene (PCE) and chloroform (TCM) are frequently detected in groundwater samples. A greater detection of CVOCs is detected during the wet season than the dry season. This is attributed to a greater capacity to flush stored contaminants during the wet season. Historical analysis of contamination in the north coast of Puerto Rico shows a high capacity of the aquifer to store and release contaminants. Future work will be focused the statistical analysis of the historical groundwater contamination data to understand the behavior of the contaminants in different hydrologic conditions.

Management of Contaminated Autologous Grafts in Plastic Surgery

PubMed Central

Centeno, Robert F; Desai, Ankit R; Watson, Marla E

2008-01-01

Background: Contamination of autologous grafts unfortunately occurs in plastic surgery, but the literature provides no guidance for management of such incidents. Methods: American Society of Aesthetic Plastic Surgery members were asked to complete an online survey that asked about the number and causes of graft contaminations experienced, how surgeons dealt with the problem, the clinical outcomes, and patient disclosure. Results: Nineteen hundred surgeons were asked to participate in the survey, and 223 responded. Of these, 70% had experienced at least 1 graft contamination incident, with 26% experiencing 4 or more. The most frequently reported reason for graft contamination was a graft falling on the floor (reported by 75%). Nearly two thirds of the contaminated grafts related to craniofacial procedures. Ninety-four percent of grafts were managed with decontamination and completion of the operation. The most common method of decontamination was washing with povidone-iodine, but this practice is contrary to recommendations in the literature. Only 3 surgeons (1.9%) said a clinical infection developed following decontaminated graft use. Patients were not informed in 60% of graft contamination incidents. The survey results and review of the literature led to development of algorithms for the management of inadvertent graft contamination and patient disclosure. Conclusions: Although autologous grafts do become contaminated in plastic surgery, the overwhelming majority can be safely decontaminated and produce minimal or no clinical sequelae. The algorithms presented are intended to serve as guides for prevention of contamination events or for their management should they occur. PMID:18496583

Space Stirling Cryocooler Contamination Lessons Learned and Recommended Control Procedures

NASA Astrophysics Data System (ADS)

Glaister, D. S.; Price, K.; Gully, W.; Castles, S.; Reilly, J.

The most important characteristic of a space cryocooler is its reliability over a lifetime typically in excess of 7 years. While design improvements have reduced the probability of mechanical failure, the risk of internal contamination is still significant and has not been addressed in a consistent approach across the industry. A significant fraction of the endurance test and flight units have experienced some performance degradation related to internal contamination. The purpose of this paper is to describe and assess the contamination issues inside long life, space cryocoolers and to recommend procedures to minimize the probability of encountering contamination related failures and degradation. The paper covers the sources of contamination, the degradation and failure mechanisms, the theoretical and observed cryocooler sensitivity, and the recommended prevention procedures and their impact. We begin with a discussion of the contamination sources, both artificial and intrinsic. Next, the degradation and failure mechanisms are discussed in an attempt to arrive at a contaminant susceptibility, from which we can derive a contamination budget for the machine. This theoretical sensitivity is then compared with the observed sensitivity to illustrate the conservative nature of the assumed scenarios. A number of lessons learned on Raytheon, Ball, Air Force Research Laboratory, and NASA GSFC programs are shared to convey the practical aspects of the contamination problem. Then, the materials and processes required to meet the proposed budget are outlined. An attempt is made to present a survey of processes across industry.

Determination of the external contamination and cross-contamination by cytotoxic drugs on the surfaces of vials available on the Swiss market.

PubMed

Fleury-Souverain, Sandrine; Nussbaumer, Susanne; Mattiuzzo, Marc; Bonnabry, Pascal

2014-04-01

The external contamination and cross-contamination by cytotoxic drugs on the surface (outside and septum) of 133 vials from various manufacturers and available on the Swiss market were evaluated. All of the tested vials contained one of the following active ingredients: cyclophosphamide, cytarabine, doxorubicin, epirubicin, etoposide phosphate, gemcitabine, ifosfamide, irinotecan, methotrexate or vincristine. The validated wiping liquid chromatography-mass spectrometry method used in this study allowed for the simultaneous determination of these 10 cytotoxic drugs in less than 30 min. External contamination by cytotoxic drugs was detected on 63% of tested vials (outside and septum). The highest contamination level was observed on etoposide phosphate vials with 1896.66 ng of active ingredient on the outside of the vial. Approximately 20% of the contaminated vials had greater than 10 ng of cytotoxic drugs. Chemical contamination on the septum was detected on 38% of the vials. No contamination or very low levels of cytotoxic drugs, less than 1 ng per vial, were detected on the vials protected by plastic shrink-wrap. Traces of cytotoxic drugs different from the active ingredient were detected on 35% of the tested vials. Handling cytotoxic vials with gloves and having a procedure for the decontamination of vials are of the utmost importance for reducing exposure to cytotoxic drugs. Moreover, manufacturers must improve their procedures to provide products free from any contamination.

Food and pharmaceuticals. Lessons learned from global contaminations with melamine/cyanuric acid and diethylene glycol.

PubMed

Brown, C A; Brown, S A

2010-01-01

Recently, contamination of pharmaceuticals with diethylene glycol (DEG) and food with melamine and cyanuric acid has demonstrated the impact of globalization on drug and food safety. By examining the details of these outbreaks, some important lessons can be learned. Toxicoses from contaminated food and drugs are often identified only when large numbers of people or animals are affected and numerous deaths result. Populations most at risk are those repeatedly exposed to a single product. Toxicoses may be complex, involving synergism among relatively nontoxic co-contaminants. Although some contamination may occur inadvertently, practices of deliberate contamination of food and drug ingredients may be widespread but escape detection in poorly regulated markets. If this deliberate contamination is motivated by personal financial gain, it is likely to recur and be concealed. The contaminated raw material produced in a poorly regulated market may cross national boundaries and be used in manufacturing processes for numerous products, sometimes in more well-regulated markets. Once in the production chain, contaminated raw materials may be widely disseminated. It is not clear that regulatory organizations have the capacity to identify significant contaminations despite their best efforts. The veterinary and medical communities, in cooperation with regulatory agencies, should develop cooperative programs designed to detect and limit these global outbreaks. Although addressing regional or national outbreaks remains an important role for regulatory agencies, the veterinary and medical communities must develop proactive global approaches to this global problem.

Contaminated land in Colombia: A critical review of current status and future approach for the management of contaminated sites.

PubMed

Arias Espana, Victor Andres; Rodriguez Pinilla, Alfonso R; Bardos, Paul; Naidu, Ravi

2018-03-15

Environmental contaminants can have negative effects on human health and land, air and water resources. Consequently, there have been significant advances in regulation for protecting the environment in developed countries including the development of remediation frameworks and guidelines. On the other hand, fewer studies have been reported on the risks and health effects of contaminants in developing regions and there is scarce information regarding contaminated land assessment and environmental remediation. Colombia is an important emerging economy and has started to take the first steps towards the development of a framework for the management of contaminated sites and there are opportunities for the country to learn from countries with well-established frameworks such as the United States (US) and the United Kingdom (UK) and for international collaboration with organisations such as CRC for Contamination Assessment and Remediation of the Environment (CARE). We review main pollution issues, current status of contaminated land management in Colombia to identify the gaps in policy and regulation. We also review the UK and US contaminated land policies and regulations to identify the elements of those experiences that could support progress in the country. Finally, we propose recommendations (e.g. risk based approach, soil screening criteria, clean-up funding, liability) for Colombia that could support further development and implementation of a more effective contaminated land management framework. Copyright © 2017 Elsevier B.V. All rights reserved.

Large-eddy simulation of human-induced contaminant transport in room compartments.

PubMed

Choi, J-I; Edwards, J R

2012-02-01

A large-eddy simulation is used to investigate contaminant transport owing to complex human and door motions and vent-system activity in room compartments where a contaminated and clean room are connected by a vestibule. Human and door motions are simulated with an immersed boundary procedure. We demonstrate the details of contaminant transport owing to human- and door-motion-induced wake development during a short-duration event involving the movement of a person (or persons) from a contaminated room, through a vestibule, into a clean room. Parametric studies that capture the effects of human walking pattern, door operation, over-pressure level, and vestibule size are systematically conducted. A faster walking speed results in less mass transport from the contaminated room into the clean room. The net effect of increasing the volume of the vestibule is to reduce the contaminant transport. The results show that swinging-door motion is the dominant transport mechanism and that human-induced wake motion enhances compartment-to-compartment transport. The effect of human activity on contaminant transport may be important in design and operation of clean or isolation rooms in chemical or pharmaceutical industries and intensive care units for airborne infectious disease control in a hospital. The present simulations demonstrate details of contaminant transport in such indoor environments during human motion events and show that simulation-based sensitivity analysis can be utilized for the diagnosis of contaminant infiltration and for better environmental protection. © 2011 John Wiley & Sons A/S.

Identification of critical contaminants in wastewater effluent for managed aquifer recharge.

PubMed

Yuan, Jie; Van Dyke, Michele I; Huck, Peter M

2017-04-01

Managed aquifer recharge (MAR) using highly treated effluent from municipal wastewater treatment plants has been recognized as a promising strategy for indirect potable water reuse. Treated wastewater effluent can contain a number of residual contaminants that could have adverse effects on human health, and some jurisdictions have regulations in place to govern these. For those that do not, but where reuse may be under consideration, it is of crucial importance to develop a strategy for identifying priority contaminants, which can then be used to understand the water treatment technologies that might be required. In this study, a multi-criteria approach to identify critical contaminants in wastewater effluent for MAR was developed and applied using a case study site located in southern Ontario, Canada. An important aspect of this approach was the selection of representative compounds for each group of contaminants, based on potential for occurrence in wastewater and expected health or environmental impacts. Due to a lack of MAR regulations in Canada, the study first proposed potential recharge water quality targets. Predominant contaminants, potential additional contaminants, and potential emerging contaminants, which together comprise critical contaminants for MAR with reclaimed water, were then selected based on the case study wastewater effluent monitoring data and literature data. This paper proposes an approach for critical contaminant selection, which will be helpful to guide future implementation of MAR projects using wastewater treatment plant effluents. Copyright © 2016 Elsevier Ltd. All rights reserved.

The holy grail of soil metal contamination site assessment: reducing risk and increasing confidence of decision making using infield portable X-ray Fluorescence (pXRF) technology

NASA Astrophysics Data System (ADS)

Rouillon, M.; Taylor, M. P.; Dong, C.

2016-12-01

This research assesses the advantages of integrating field portable X-ray Fluorescence (pXRF) technology for reducing the risk and increase confidence of decision making for metal-contaminated site assessments. Metal-contaminated sites are often highly heterogeneous and require a high sampling density to accurately characterize the distribution and concentration of contaminants. The current regulatory assessment approaches rely on a small number of samples processed using standard wet-chemistry methods. In New South Wales (NSW), Australia, the current notification trigger for characterizing metal-contaminated sites require the upper 95% confidence interval of the site mean to equal or exceed the relevant guidelines. The method's low `minimum' sampling requirements can misclassify sites due to the heterogeneous nature of soil contamination, leading to inaccurate decision making. To address this issue, we propose integrating infield pXRF analysis with the established sampling method to overcome sampling limitations. This approach increases the minimum sampling resolution and reduces the 95% CI of the site mean. Infield pXRF analysis at contamination hotspots enhances sample resolution efficiently and without the need to return to the site. In this study, the current and proposed pXRF site assessment methods are compared at five heterogeneous metal-contaminated sites by analysing the spatial distribution of contaminants, 95% confidence intervals of site means, and the sampling and analysis uncertainty associated with each method. Finally, an analysis of costs associated with both the current and proposed methods is presented to demonstrate the advantages of incorporating pXRF into metal-contaminated site assessments. The data shows that pXRF integrated site assessments allows for faster, cost-efficient, characterisation of metal-contaminated sites with greater confidence for decision making.

[Simulation on contamination forecast and control of groundwater in a certain hazardous waste landfill].

PubMed

Ma, Zhi-Fei; An, Da; Jiang, Yong-Hai; Xi, Bei-Dou; Li, Ding-Long; Zhang, Jin-Bao; Yang, Yu

2012-01-01

On the basis of site investigation and data collection of a certain hazardous waste landfill, the groundwater flow and solute transport coupled models were established by applying Visual Modflow software, which was used to conduct a numerical simulation that forecast the transport process of Cr6+ in groundwater and the effects of three control measures (ground-harden, leakage-proof barriers and drainage ditches) of contaminants transport after leachate leakage happened in impermeable layer of the landfill. The results show that the contamination plume of Cr6+ transports with groundwater flow direction, the contamination rang would reach the pool's boundary in 10 years, and the distance of contamination transport is 1 450 m. But the diffusion range of contamination plume would not be obviously expanded between 10 and 20 years. While the ground is hardened, the contamination plume would not reach the pool's boundary in 20 years. When the leakage-proof barrier is set in the bottom of water table aquifer, the concentration of Cr6+ is higher than that the leakage-proof barrier is unset, but the result is just opposite when setting the leakage-proof barrier in the bottom of underlying aquifer. The range of contamination plume is effectively controlled by setting drainage ditches that water discharge is 2 642 m3 x d(-1), which makes the monitoring wells would not be contaminated in 20 years. Moreover, combining the ground-harden with drainage ditches can get the best effect in controlling contaminants diffusion, and meanwhile, the drainage ditches' daily discharge is reduced to 1 878 m3 x d(-1). Therefore, it is suggested that the control measure combining the ground-harden with drainage ditches should apply to prevent contamination diffusion in groundwater when leachate leakage have happened in impermeable layer of the landfill.

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.

Coagulase-negative staphylococcal bacteraemia in cancer patients. Time to positive culture can distinguish bacteraemia from contamination.

PubMed

Morioka, Shinichiro; Ichikawa, Mika; Mori, Keita; Kurai, Hanako

2018-03-16

Coagulase-negative staphylococci (CoNS) are the most common contaminants of blood cultures, however, we sometimes have difficulties in determining their clinical significance. It is still controversial that there is a significant difference between the contamination group and the true bacteraemia group in the time to positivity (TTP) of blood cultures. We validated the relationship between a TTP and the presence of CoNS bacteraemia in cancer patients by using an objective, non-judgmental definition for CoNS contamination. We retrospectively reviewed 175 sets of blood cultures drawn from 95 patients that yielded CoNS from October 2011 to March 2013. We considered as contamination if an isolate of CoNS was identified in one out of multiple sets of blood cultures. We investigated the TTP, the threshold values and corresponding likelihood ratios to distinguish CoNS bacteraemia from contamination. The median TTP in CoNS bacteraemia group was significantly shorter than that in contamination group (14 h 45 min and 20 h 31 min, respectively, p = .0157). A TTP of ≤16 h had a specificity of 83% for predicting CoNS bacteraemia, and that of >20 h had a sensitivity of 86% for predicting CoNS contamination. We validated that the median TTP in CoNS bacteraemia group was significantly shorter than that in their contamination group, and that a TTP of ≤16 h was associated with CoNS bacteraemia, while that of >20 h was associated with CoNS contamination, if evaluated with an objective, non-judgmental definition for CoNS contamination.

Evaluation of deep vadose zone contaminant flux into groundwater: Approach and case study

NASA Astrophysics Data System (ADS)

Oostrom, M.; Truex, M. J.; Last, G. V.; Strickland, C. E.; Tartakovsky, G. D.

2016-06-01

For sites with a contaminant source located in the vadose zone, the nature and extent of groundwater contaminant plumes are a function of the contaminant flux from the vadose zone to groundwater. Especially for thick vadose zones, transport may be relatively slow making it difficult to directly measure contaminant flux. An integrated assessment approach, supported by site characterization and monitoring data, is presented to explain current vadose zone contaminant distributions and to estimate future contaminant flux to groundwater in support of remediation decisions. The U.S. Department of Energy Hanford Site (WA, USA) SX Tank Farm was used as a case study because of a large existing contaminant inventory in its deep vadose zone, the presence of a limited-extent groundwater plume, and the relatively large amount of available data for the site. A predictive quantitative analysis was applied to refine a baseline conceptual model through the completion of a series of targeted simulations. The analysis revealed that site recharge is the most important flux-controlling process for future contaminant flux. Tank leak characteristics and subsurface heterogeneities appear to have a limited effect on long-term contaminant flux into groundwater. The occurrence of the current technetium-99 groundwater plume was explained by taking into account a considerable historical water-line leak adjacent to one of the tanks. The analysis further indicates that the vast majority of technetium-99 is expected to migrate into the groundwater during the next century. The approach provides a template for use in evaluating contaminant flux to groundwater using existing site data and has elements that are relevant to other disposal sites with a thick vadose zone.

Groundwater Flow Model of Corrective Action Units 101 and 102: Central and Western Pahute Mesa, Nevada Test Site, Nye County, Nevada, Revision 0

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

Greg Ruskauff

2006-06-01

The Pahute Mesa groundwater flow model supports the FFACO UGTA corrective action strategy objective of providing an estimate of the vertical and horizontal extent of contaminant migration for each CAU in order to predict contaminant boundaries. A contaminant boundary is the model-predicted perimeter that defines the extent of radionuclide-contaminated groundwater from underground nuclear testing above background conditions exceeding Safe Drinking Water Act (SDWA) standards. The contaminant boundary will be composed of both a perimeter boundary and a lower hydrostratigraphic unit (HSU) boundary. Additional results showing contaminant concentrations and the location of the contaminant boundary at selected times will also bemore » presented. These times may include the verification period, the end of the five-year proof-of-concept period, as well as other times that are of specific interest. The FFACO (1996) requires that the contaminant transport model predict the contaminant boundary at 1,000 years and “at a 95% level of confidence.” The Pahute Mesa Phase I flow model described in this report provides, through the flow fields derived from alternative hydrostratigraphic framework models (HFMs) and recharge models, one part of the data required to compute the contaminant boundary. Other components include the simplified source term model, which incorporates uncertainty and variability in the factors that control radionuclide release from an underground nuclear test (SNJV, 2004a), and the transport model with the concomitant parameter uncertainty as described in Shaw (2003). The uncertainty in all the above model components will be evaluated to produce the final contaminant boundary. This report documents the development of the groundwater flow model for the Central and Western Pahute Mesa CAUs.« less

Hydraulic and geochemical framework of the Idaho National Engineering and Environmental Laboratory vadose zone

USGS Publications Warehouse

Nimmo, John R.; Rousseau, Joseph P.; Perkins, Kim S.; Stollenwerk, Kenneth G.; Glynn, Pierre D.; Bartholomay, Roy C.; Knobel, LeRoy L.

2004-01-01

Questions of major importance for subsurface contaminant transport at the Idaho National Engineering and Environmental Laboratory (INEEL) include (i) travel times to the aquifer, both average or typical values and the range of values to be expected, and (ii) modes of contaminant transport, especially sorption processes. The hydraulic and geochemical framework within which these questions are addressed is dominated by extreme heterogeneity in a vadose zone and aquifer consisting of interbedded basalts and sediments. Hydraulically, major issues include diverse possible types of flow pathways, extreme anisotropy, preferential flow, combined vertical and horizontal flow, and temporary saturation or perching. Geochemically, major issues include contaminant mobility as influenced by redox conditions, the concentration of organic and inorganic complexing solutes and other local variables, the interaction with infiltrating waters and with the contaminant source environment, and the aqueous speciation of contaminants such as actinides. Another major issue is the possibility of colloid transport, which inverts some of the traditional concepts of mobility, as sorbed contaminants on mobile colloids may be transported with ease compared with contaminants that are not sorbed. With respect to the goal of minimizing aquifer concentrations of contaminants, some characteristics of the vadose zone are essentially completely favorable. Examples include the great thickness (200 m) of the vadose zone, and the presence of substantial quantities of fine sediments that can retard contaminant transport both hydraulically and chemically. Most characteristics, however, have both favorable and unfavorable aspects. For example, preferential flow, as promoted by several notable features of the vadose zone at the INEEL, can provide fast, minimally sorbing pathways for contaminants to reach the aquifer easily, but it also leads to a wide dispersal of contaminants in a large volume of subsurface material, thus increasing the opportunity for dilution and sorption.