Drilling Fluid Contamination during Riser Drilling Quantified by Chemical and Molecular Tracers

NASA Astrophysics Data System (ADS)

Inagaki, F.; Lever, M. A.; Morono, Y.; Hoshino, T.

2012-12-01

Stringent contamination controls are essential to any type of microbiological investigation, and are particularly challenging in ocean drilling, where samples are retrieved from hundreds of meters below the seafloor. In summer 2012, Integrated Ocean Drilling Expedition 337 aboard the Japanese vessel Chikyu pioneered the use of chemical tracers in riser drilling while exploring the microbial ecosystem of coalbeds 2 km below the seafloor off Shimokita, Japan. Contamination tests involving a perfluorocarbon tracer that had been successfully used during past riserless drilling expeditions were complemented by DNA-based contamination tests. In the latter, likely microbial contaminants were targeted via quantitative polymerase chain reaction assays using newly designed, group-specific primers. Target groups included potential indicators of (a) drilling mud viscosifiers (Xanthomonas, Halomonas), (b) anthropogenic wastewater (Bifidobacterium, Blautia, Methanobrevibacter), and (c) surface seawater (SAR 11, Marine Group I Archaea). These target groups were selected based on past evidence suggesting viscosifiers, wastewater, and seawater as the main sources of microbial contamination in cores retrieved by ocean drilling. Analyses of chemical and molecular tracers are in good agreement, and indicate microorganisms associated with mud viscosifiers as the main contaminants during riser drilling. These same molecular analyses are then extended to subseafloor samples obtained during riserless drilling operations. General strategies to further reduce the risk of microbial contamination during riser and riserless drilling operations are discussed.

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.

Molecular barcodes detect redundancy and contamination in hairpin-bisulfite PCR

PubMed Central

Miner, Brooks E.; Stöger, Reinhard J.; Burden, Alice F.; Laird, Charles D.; Hansen, R. Scott

2004-01-01

PCR amplification of limited amounts of DNA template carries an increased risk of product redundancy and contamination. We use molecular barcoding to label each genomic DNA template with an individual sequence tag prior to PCR amplification. In addition, we include molecular ‘batch-stamps’ that effectively label each genomic template with a sample ID and analysis date. This highly sensitive method identifies redundant and contaminant sequences and serves as a reliable method for positive identification of desired sequences; we can therefore capture accurately the genomic template diversity in the sample analyzed. Although our application described here involves the use of hairpin-bisulfite PCR for amplification of double-stranded DNA, the method can readily be adapted to single-strand PCR. Useful applications will include analyses of limited template DNA for biomedical, ancient DNA and forensic purposes. PMID:15459281

Surface accommodation of molecular contaminants

NASA Technical Reports Server (NTRS)

Chen, Philip T.; Hedgeland, Randy J.; Thomson, Shaun R.

1990-01-01

Theoretical consideration and supporting data are presented regarding the nature of the transport mechanisms which cause the adsorption of gases on spacecraft surfaces. Particular attention is given to the concept of a sticking coefficient which is the ratio of the thermally accommodated mass to the total incident mass. Existing molecular accommodation data are examined in terms of spacecraft applications and recent contamination-control data are introduced. Two distinct yet linked concepts emerge which are the accommodation and sticking coefficients, and surface roughness contributes significantly to both coefficients. A general equation regarding the coefficients is developed, and the data are found to fit the equation basically. It is concluded that a more precise characterization of the coefficients can be obtained through experimentation under simulated spacecraft conditions.

Statistical Evaluation of Molecular Contamination During Spacecraft Thermal Vacuum Test

NASA Technical Reports Server (NTRS)

Chen, Philip; Hedgeland, Randy; Montoya, Alex; Roman-Velazquez, Juan; Dunn, Jamie; Colony, Joe; Petitto, Joseph

1998-01-01

The purpose of this paper is to evaluate the statistical molecular contamination data with a goal to improve spacecraft contamination control. The statistical data was generated in typical thermal vacuum tests at the National Aeronautics and Space Administration, Goddard Space Flight Center (GSFC). The magnitude of material outgassing was measured using a Quartz Crystal Microbalance (QCM) device during the test. A solvent rinse sample was taken at the conclusion of each test. Then detailed qualitative and quantitative measurements were obtained through chemical analyses. All data used in this study encompassed numerous spacecraft tests in recent years.

Statistical Evaluation of Molecular Contamination During Spacecraft Thermal Vacuum Test

NASA Technical Reports Server (NTRS)

Chen, Philip; Hedgeland, Randy; Montoya, Alex; Roman-Velazquez, Juan; Dunn, Jamie; Colony, Joe; Petitto, Joseph

1999-01-01

The purpose of this paper is to evaluate the statistical molecular contamination data with a goal to improve spacecraft contamination control. The statistical data was generated in typical thermal vacuum tests at the National Aeronautics and Space Administration, Goddard Space Flight Center (GSFC). The magnitude of material outgassing was measured using a Quartz Crystal Microbalance (QCNO device during the test. A solvent rinse sample was taken at the conclusion of each test. Then detailed qualitative and quantitative measurements were obtained through chemical analyses. All data used in this study encompassed numerous spacecraft tests in recent years.

Statistical Evaluation of Molecular Contamination During Spacecraft Thermal Vacuum Test

NASA Technical Reports Server (NTRS)

Chen, Philip; Hedgeland, Randy; Montoya, Alex; Roman-Velazquez, Juan; Dunn, Jamie; Colony, Joe; Petitto, Joseph

1997-01-01

The purpose of this paper is to evaluate the statistical molecular contamination data with a goal to improve spacecraft contamination control. The statistical data was generated in typical thermal vacuum tests at the National Aeronautics and Space Administration, Goddard Space Flight Center (GSFC). The magnitude of material outgassing was measured using a Quartz Crystal Microbalance (QCM) device during the test. A solvent rinse sample was taken at the conclusion of the each test. Then detailed qualitative and quantitative measurements were obtained through chemical analyses. All data used in this study encompassed numerous spacecraft tests in recent years.

Vacuum Ultraviolet Radiation Desorption of Molecular Contaminants Deposited on Quartz Crystal Microbalances

NASA Technical Reports Server (NTRS)

Albyn, Keith; Burns, Dewitt

2006-01-01

Recent quartz crystal microbalance measurements made in the Marshall Space Flight Center, Photo-Deposition Facility, for several materials, recorded a significant loss of deposited contaminants when the deposition surface of the microbalance was illuminated by a deuterium lamp. These measurements differ from observations made by other investigators in which the rate of deposition increased significantly when the deposition surface was illuminated with vacuum ultraviolet radiation. These observations suggest that the accelerated deposition of molecular contaminants on optically sensitive surfaces is dependant upon the contaminant being deposited and must be addressed during the materials selection process by common material screening techniques.

Application of computer-assisted molecular modeling (CAMM) for immunoassay of low molecular weight food contaminants: A review

USDA-ARS?s Scientific Manuscript database

Immunoassay for low molecular weight food contaminants, such as pesticides, veterinary drugs, and mycotoxins is now a well-established technique which meets the demands for a rapid, reliable, and cost-effective analytical method. However, due to limited understanding of the fundamental aspects of i...

A study on EUV reticle surface molecular contamination under different storage conditions in a HVM foundry fab

NASA Astrophysics Data System (ADS)

Singh, SherJang; Yatzor, Brett; Taylor, Ron; Wood, Obert; Mangat, Pawitter

2017-03-01

The prospect of EUVL (Extreme Ultraviolet Lithography) insertion into HVM (High Volume Manufacturing) has never been this promising. As technology is prepared for "lab to fab" transition, it becomes important to comprehend challenges associated with integrating EUVL infrastructure within existing high volume chip fabrication processes in a foundry fab. The existing 193nm optical lithography process flow for reticle handling and storage in a fab atmosphere is well established and in-fab reticle contamination concerns are mitigated with the reticle pellicle. However EUVL reticle pellicle is still under development and if available, may only provide protection against particles but not molecular contamination. HVM fab atmosphere is known to be contaminated with trace amounts of AMC's (Atmospheric Molecular Contamination). If such contaminants are organic in nature and get absorbed on the reticle surface, EUV photon cause photo-dissociation resulting into carbon generation which is known to reduce multilayer reflectivity and also degrades exposure uniformity. Chemical diffusion and aggregation of other ions is also reported under the e-beam exposure of a EUV reticle which is known to cause haze issues in optical lithography. Therefore it becomes paramount to mitigate absorbed molecular contaminant concerns on EUVL reticle surface. In this paper, we have studied types of molecular contaminants that are absorbed on an EUVL reticle surface under HVM fab storage and handling conditions. Effect of storage conditions (gas purged vs atmospheric) in different storage pods (Dual pods, Reticle Clamshells) is evaluated. Absorption analysis is done both on ruthenium capping layer as well as TaBN absorber. Ru surface chemistry change as a result of storage is also studied. The efficacy of different reticle cleaning processes to remove absorbed contaminant is evaluated as well.

Molecular testing of Klebsiella pneumoniae contaminating tissue allografts recovered from deceased donors.

PubMed

Ghalavand, Zohreh; Heidary Rouchi, Alireza; Bahraminasab, Hassan; Ravanasa, Elham; Mirsamadi, Elnaz Sadat; Nodeh Farahani, Narges; Nikmanesh, Bahram

2018-02-03

Microbiological screening of tissue allografts is crucial to prevent the transmission of bacterial and fungal infections to transplant recipients. Klebsiella was the most prevalent and resistant contaminating microorganism observed in our setting in the Iranian Tissue Bank. This study was conducted to determine the presence of extended-spectrum β-lactamase (ESBL) genes, antimicrobial resistance patterns of Klebsiella pneumoniae isolates, and their clonal relationships in allograft materials. K. pneumoniae contaminating bone and other tissue allografts recovered from deceased donors were identified and ESBL isolates were detected using a phenotypic confirmatory method. Antimicrobial susceptibility testing was carried out using the disk diffusion method. Distribution of ESBL genes and molecular typing were performed using polymerase chain reaction (PCR) and Repetitive-element (rep-PCR) methods. Of 3828 donated tissues, 51 (1.3%) were found contaminated by K. pneumoniae isolates. Compared to tissue allografts from brain-dead, heart-beating tissue donors, allografts from donors with circulatory cessation were associated with a higher risk of K. pneumoniae contamination [odds ratio (OR), 1.2 (CI 95% 0.9-2.3) (P value < 0.001)]. Half of the isolates produced ESBL, and the rate of susceptibility to cephalosporins was 51%. Among isolates, 22 (43.1%) harbored CTX-M, 31 (60.8%) SHV, and 9 (17.6%) harbored TEM types. The rep-dendrogram indicated that clones having identical or related strains with a similar antibiotype were isolated in the same period. This study provides evidence that a single clone of K. pneumoniae contaminated tissue allografts recovered from many different donors. A single clone found on tissues from several donors suggests contamination of tissues from a single source such as the tissue recovery process and environment. Genomic DNA testing and clonality of contaminating bacteria using molecular methods can focus the epidemiologic investigation on the

Regional risk assessment for contaminated sites part 2: ranking of potentially contaminated sites.

PubMed

Pizzol, Lisa; Critto, Andrea; Agostini, Paola; Marcomini, Antonio

2011-11-01

Environmental risks are traditionally assessed and presented in non spatial ways although the heterogeneity of the contaminants spatial distributions, the spatial positions and relations between receptors and stressors, as well as the spatial distribution of the variables involved in the risk assessment, strongly influence exposure estimations and hence risks. Taking into account spatial variability is increasingly being recognized as a further and essential step in sound exposure and risk assessment. To address this issue an innovative methodology which integrates spatial analysis and a relative risk approach was developed. The purpose of this methodology is to prioritize sites at regional scale where a preliminary site investigation may be required. The methodology aimed at supporting the inventory of contaminated sites was implemented within the spatial decision support sYstem for Regional rIsk Assessment of DEgraded land, SYRIADE, and was applied to the case-study of the Upper Silesia region (Poland). The developed methodology and tool are both flexible and easy to adapt to different regional contexts, allowing the user to introduce the regional relevant parameters identified on the basis of user expertise and regional data availability. Moreover, the used GIS functionalities, integrated with mathematical approaches, allow to take into consideration, all at once, the multiplicity of sources and impacted receptors within the region of concern, to assess the risks posed by all contaminated sites in the region and, finally, to provide a risk-based ranking of the potentially contaminated sites. Copyright © 2011. Published by Elsevier Ltd.

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.

Developing an integration tool for soil contamination assessment

NASA Astrophysics Data System (ADS)

Anaya-Romero, Maria; Zingg, Felix; Pérez-Álvarez, José Miguel; Madejón, Paula; Kotb Abd-Elmabod, Sameh

2015-04-01

In the last decades, huge soil areas have been negatively influenced or altered in multiples forms. Soils and, consequently, underground water, have been contaminated by accumulation of contaminants from agricultural activities (fertilizers and pesticides) industrial activities (harmful material dumping, sludge, flying ashes) and urban activities (hydrocarbon, metals from vehicle traffic, urban waste dumping). In the framework of the RECARE project, local partners across Europe are focusing on a wide range of soil threats, as soil contamination, and aiming to develop effective prevention, remediation and restoration measures by designing and applying targeted land management strategies (van Lynden et al., 2013). In this context, the Guadiamar Green Corridor (Southern Spain) was used as a case study, aiming to obtain soil data and new information in order to assess soil contamination. The main threat in the Guadiamar valley is soil contamination after a mine spill occurred on April 1998. About four hm3 of acid waters and two hm3 of mud, rich in heavy metals, were released into the Agrio and Guadiamar rivers affecting more than 4,600 ha of agricultural and pasture land. Main trace elements contaminating soil and water were As, Cd, Cu, Pb, Tl and Zn. The objective of the present research is to develop informatics tools that integrate soil database, models and interactive platforms for soil contamination assessment. Preliminary results were obtained related to the compilation of harmonized databases including geographical, hydro-meteorological, soil and socio-economic variables based on spatial analysis and stakeholder's consultation. Further research will be modellization and upscaling at the European level, in order to obtain a scientifically-technical predictive tool for the assessment of soil contamination.

The JCMT Gould Belt Survey: the effect of molecular contamination in SCUBA-2 observations of Orion A

NASA Astrophysics Data System (ADS)

Coudé, S.; Bastien, P.; Kirk, H.; Johnstone, D.; Drabek-Maunder, E.; Graves, S.; Hatchell, J.; Chapin, E. L.; Gibb, A. G.; Matthews, B.; JCMT Gould Belt Survey Team

2016-04-01

Thermal emission from cold dust grains in giant molecular clouds can be used to probe the physical properties, such as density, temperature and emissivity in star-forming regions. We present the Submillimetre Common-User Bolometer Array (SCUBA-2) shared-risk observations at 450 and 850 μm of the Orion A molecular cloud complex taken at the James Clerk Maxwell Telescope (JCMT). Previous studies showed that molecular emission lines can contribute significantly to the measured fluxes in those continuum bands. We use the Heterodyne Array Receiver Programme 12CO J = 3-2 integrated intensity map for Orion A in order to evaluate the molecular line contamination and its effects on the SCUBA-2 maps. With the corrected fluxes, we have obtained a new spectral index α map for the thermal emission of dust in the well-known integral-shaped filament. Furthermore, we compare a sample of 33 sources, selected over the Orion A molecular cloud complex for their high 12CO J = 3-2 line contamination, to 27 previously identified clumps in OMC 4. This allows us to quantify the effect of line contamination on the ratio of 850-450 μm flux densities and how it modifies the deduced spectral index of emissivity β for the dust grains. We also show that at least one Spitzer-identified protostellar core in OMC 5 has a 12CO J = 3-2 contamination level of 16 per cent. Furthermore, we find the strongest contamination level (44 per cent) towards a young star with disc near OMC 2. This work is part of the JCMT Gould Belt Legacy Survey.

TRACKING FECAL CONTAMINATION WITH BACTEROIDALES MOLECULAR MARKERS: AN ANALYSIS OF THE DYNAMICS OF FECAL CONTAMINATION IN THE TILLAMOOK BASIN, OREGON

EPA Science Inventory

Although amplification of source-specific molecular markers from Bacteroidales fecal bacteria can identify several different kinds of fecal contamination in water, it remains unclear how this technique relates to fecal indicator measurements in natural waters. The objectives of t...

Molecular sieves control contamination and and insulate in thermal regenerators - A concept

NASA Technical Reports Server (NTRS)

Gasser, M. G.

1970-01-01

Zeolitic molecular sieves prolong the lives of cryogenic engines by preventing contamination of the thermal regenerators on the cold ends of closed-cycle engines. Sieves also serve as thermal insulators by preventing conduction of heat along regenerators through contiguous disks of mesh.

Effects of low molecular weight organic acids on (137)Cs release from contaminated soils.

PubMed

Chiang, Po Neng; Wang, Ming Kuang; Huang, Pan Ming; Wang, Jeng Jong

2011-06-01

Radio pollutant removal is one of several priority restoration strategies for the environment. This study assessed the effect of low molecular weight organic acid on the lability and mechanisms for release of (137)Cs from contaminated soils. The amount of (137)Cs radioactivity released from contaminated soils reacting with 0.02 M low molecular weight organic acids (LMWOAs) specifically acetic, succinic, oxalic, tartaric, and citric acid over 48 h were 265, 370, 760, 850, and 1002 Bq kg(-1), respectively. The kinetic results indicate that (137)Cs exhibits a two-step parabolic diffusion equation and a good linear relationship, indicating that the parabolic diffusion equation describes the data quite well, as shown by low p and high r(2) values. The fast stage, which was found to occur within a short period of time (0.083-3 h), corresponds to the interaction of LMWOAs with the surface of clay minerals; meanwhile, during the slow stage, which occurs over a much longer time period (3-24 h), desorption primarily is attributed to inter-particle or intra-particle diffusion. After a fifth renewal of the LMWOAs, the total levels of (137)Cs radioactivity released by acetic, succinic, oxalic, tartaric, and citric acid were equivalent to 390, 520, 3949, 2061, and 4422 Bq kg(-1) soil, respectively. H(+) can protonate the hydroxyl groups and oxygen atoms at the broken edges or surfaces of the minerals, thereby weakening Fe-O and Al-O bonds. After protonation of H(+), organic ligands can attack the OH and OH(2) groups in the minerals easily, to form complexes with surface structure cations, such as Al and Fe. The amounts of (137)Cs released from contaminated soil treated with LMWOAs were substantially increased, indicating that the LMWOAs excreted by the roots of plants play a critical role in (137)Cs release. Copyright © 2011 Elsevier Ltd. All rights reserved.

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.

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: 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

The Effect of Molecular Contamination on the Emissivity Spectral Index in Orion A

NASA Astrophysics Data System (ADS)

Coudé, Simon; Bastien, Pierre; Drabek, Emily; Johnstone, Doug; Hatchell, Jennifer

2013-07-01

The emissivity spectral index is a critical component in the study of the physical properties of dust grains in cold and optically thin interstellar star forming regions. Since submillimeter astronomy is an ideal tool to measure the thermal emission of those dust grains, it can be used to characterize this important parameter. We present the SCUBA-2 shared risks observations at 450 μm and 850 μm of the Orion A molecular cloud obtained at the James-Clerk-Maxwell telescope. Previous studies showed that molecular emission lines can also contribute significantly to the measured fluxes in those continuum bands. We use HARP 12CO 3-2 maps to evaluate the total molecular line contamination in the SCUBA-2 maps and its effect on the determination of the spectral index in highly contaminated areas. With the corrected fluxes, we have obtained new spectral index maps for different regions of the well-known integral-shaped filament. This work is part of an ongoing effort to characterize the properties of star forming regions in the Gould belt with the new instruments available at the JCMT.

Chemometric assessment of enhanced bioremediation of oil contaminated soils.

PubMed

Soleimani, Mohsen; Farhoudi, Majid; Christensen, Jan H

2013-06-15

Bioremediation is a promising technique for reclamation of oil polluted soils. In this study, six methods for enhancing bioremediation were tested on oil contaminated soils from three refinery areas in Iran (Isfahan, Arak, and Tehran). The methods included bacterial enrichment, planting, and addition of nitrogen and phosphorous, molasses, hydrogen peroxide, and a surfactant (Tween 80). Total petroleum hydrocarbon (TPH) concentrations and CHEMometric analysis of Selected Ion Chromatograms (SIC) termed CHEMSIC method of petroleum biomarkers including terpanes, regular, diaromatic and triaromatic steranes were used for determining the level and type of hydrocarbon contamination. The same methods were used to study oil weathering of 2 to 6 ring polycyclic aromatic compounds (PACs). Results demonstrated that bacterial enrichment and addition of nutrients were most efficient with 50% to 62% removal of TPH. Furthermore, the CHEMSIC results demonstrated that the bacterial enrichment was more efficient in degradation of n-alkanes and low molecular weight PACs as well as alkylated PACs (e.g. C₃-C₄ naphthalenes, C₂ phenanthrenes and C₂-C₃ dibenzothiophenes), while nutrient addition led to a larger relative removal of isoprenoids (e.g. norpristane, pristane and phytane). It is concluded that the CHEMSIC method is a valuable tool for assessing bioremediation efficiency. Copyright © 2013 Elsevier B.V. All rights reserved.

Contamination of grazing incidence EUV mirrors - An assessment

NASA Technical Reports Server (NTRS)

Osantowski, John F.; Fleetwood, C. F.

1988-01-01

Contamination assessment for space optical systems requires an understanding of the sensitivity of component performance, e.g. mirror reflectance, to materials deposited on the mirror surface. In a previous study, the sensitivity of typical normal incidence mirror coatings to surface deposits of generic hydrocarbons was reported. Recent activity in the development of grazing incidence telescopes for extreme ultraviolet space astronomy has stimulated the need for a similar assessment in the spectral region extending from approximately 100 A to 1000 A. The model used for analysis treats the contamination layer as a continuous thin film deposited on the mirror surface. The mirror surfaces selected for this study are opaque vacuum deposited gold and the uncoated and polished Zerodur. Scatter caused by film irregularities or particulates are not included in this assessment. Parametric evaluations at 100, 500, and 1000 A determine the sensitivity of mirror reflectance to a range of optical constants selected for the generic contaminants. This sensitivity analysis combined with the limited amount of optical data in the EUV for hydrocarbons, is used to select representative optical constants for the three wavelength regions. Reflectance versus contamination layer thickness curves are then calculated and used to determine critical thickness limits based on allowable reflectance change. Initial observations indicate that thickness limits will be highly dependent on the real part of the complex index of refraction of the contaminant film being less than 1.0. Preliminary laboratory measurements of samples contaminated with some commonly encountered hydrocarbons confirm trends indicated in the analytical studies.

Energy level alignment and molecular conformation at rubrene/Ag interfaces: Impact of contact contaminations on the interfaces

NASA Astrophysics Data System (ADS)

Sinha, Sumona; Wang, C.-H.; Mukherjee, M.

2017-07-01

This paper addresses the impact of electrode contaminations on the interfacial energy level alignment, the molecular conformation, orientation and surface morphology deposited organic film at organic semiconductor/noble metal interfaces by varying of film thickness from sub-monolayer to multilayer, which currently draws significant attention with regard to its application in organic electronics. The UHV clean Ag and unclean Ag were employed as substrate whereas rubrene was used as an organic semiconducting material. The photoelectron spectroscopy (XPS and UPS) was engaged to investigate the evolution of interfacial energetics; polarization dependent near edge x-ray absorption fine structure spectroscopy (NEXAFS) was employed to understand the molecular conformation as well as orientation whereas atomic force microscopy (AFM) was used to investigate the surface morphologies of the films. The adventitious contamination layer was acted as a spacer layer between clean Ag substrate surface and rubrene molecular layer. As a consequence, hole injection barrier height, interface dipole as well as molecular-conformation, molecular-orientation and surface morphology of rubrene thin films were found to depend on the cleanliness of Ag substrate. The results have important inferences about the understanding of the impact of substrate contamination on the energy level alignment, the molecular conformation as well as orientation and surface morphology of deposited rubrene thin film at rubrene/Ag interfaces and are beneficial for the improvement of the device performance.

MOLECULAR EVALUATION OF CHANGES IN PLANKTONIC BACTERIAL POPULATIONS RESULTING FROM EQUINE FECAL CONTAMINATION IN A SUB-WATERSHED

EPA Science Inventory

Considerable emphasis has been placed on developing watershed-based strategies with the potential to reduce non-point-source fecal contamination. Molecular methods applied used 16S-ribosomal-deoxyribonucleic-acid (rDNA) to try to determine sources of fecal contamination. Objectiv...

Contamination assessment and control in scientific satellites

NASA Technical Reports Server (NTRS)

Naumann, R. J.

1973-01-01

Techniques for assessment and control of the contamination environment for both particulates and condensible vapors in the vicinity of spacecraft are developed. An analysis of the deposition rate on critical surfaces is made considering sources within the line of sight of the surface in question as well as those obscured from the line of sight. The amount of contamination returned by collision with the surrounding atmosphere is estimated. Scattering and absorption from the induced atmosphere of gases and particulates around the spacecraft are estimated. Finally, design techniques developed for Skylab to reduce the contamination environment to an acceptable level are discussed.

Removing external DNA contamination from arthropod predators destined for molecular gut-content analysis

USDA-ARS?s Scientific Manuscript database

Molecular gut-content analysis enables detection of arthropod predation with minimal disruption of ecosystem processes. Field and laboratory experiments have demonstrated that mass-collection methods, such as sweep-netting, vacuum sampling, and foliage beating, can lead to contamination of fed pred...

Assessment of the probability of contaminating Mars

NASA Technical Reports Server (NTRS)

Judd, B. R.; North, D. W.; Pezier, J. P.

1974-01-01

New methodology is proposed to assess the probability that the planet Mars will by biologically contaminated by terrestrial microorganisms aboard a spacecraft. Present NASA methods are based on the Sagan-Coleman formula, which states that the probability of contamination is the product of the expected microbial release and a probability of growth. The proposed new methodology extends the Sagan-Coleman approach to permit utilization of detailed information on microbial characteristics, the lethality of release and transport mechanisms, and of other information about the Martian environment. Three different types of microbial release are distinguished in the model for assessing the probability of contamination. The number of viable microbes released by each mechanism depends on the bio-burden in various locations on the spacecraft and on whether the spacecraft landing is accomplished according to plan. For each of the three release mechanisms a probability of growth is computed, using a model for transport into an environment suited to microbial growth.

1H NMR Metabolomics: A New Molecular Level Tool for Assessment of Organic Contaminant Bioavailability to Earthworms in Soil

NASA Astrophysics Data System (ADS)

McKelvie, J. R.; Wolfe, D. M.; Celejewski, M. A.; Simpson, A. J.; Simpson, M. J.

2009-05-01

At contaminated field sites, the complete removal of polycyclic aromatic hydrocarbons (PAHs) is rarely achieved since a portion of these compounds remain tightly bound to the soil matrix. The concentration of PAHs in soil typically decreases until a plateau is reached, at which point the remaining contaminant is considered non- bioavailable. Numerous soil extraction techniques, including cyclodextrin extraction, have been developed to estimate contaminant bioavailability. However, these are indirect methods that do not directly measure the response of organisms to chemical exposure in soil. Earthworm metabolomics offers a promising new way to directly evaluate the bioavailability and toxicity of contaminants in soil. Metabolomics involves the measurement of changes in small-molecule metabolites, including sugars and amino acids, in living organisms due to an external stress, such as contaminant exposure. The objective of this study was to compare cyclodextrin extraction of soil (a bioavailability proxy) and 1H NMR metabolomic analysis of aqueous earthworm tissue extracts as indicators of contaminant bioavailability. A 30 day laboratory experiment was conducted using phenanthrene-spiked sphagnum peat soil and the OECD recommended earthworm species for toxicity testing, Eisenia fetida. The initial phenanthrene concentration in the soil was 320 mg/kg. Rapid biodegradation of phenanthrene occurred and concentrations decreased to 16 mg/kg within 15 days. After 15 days, phenanthrene biodegradation slowed and cyclodextrin extraction of the soil suggested that phenanthrene was no longer bioavailable. Multivariate statistical analysis of the 1H NMR spectra for E. fetida tissue extracts indicated that the metabolic profile of phenanthrene exposed earthworms differed from control earthworms throughout the 30 day experiment. This suggests that the residual phenanthrene remaining in the soil after 15 days continued to elicit a metabolic response, even though it was not

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.

Fungal contamination assessment in Portuguese elderly care centers.

PubMed

Viegas, C; Almeida-Silva, M; Gomes, A Quintal; Wolterbeek, H T; Almeida, S M

2014-01-01

Individuals spend 80-90% of their day indoors and elderly subjects are likely to spend even a greater amount of time indoors. Thus, indoor air pollutants such as bioaerosols may exert a significant impact on this age group. The aim of this study was to characterize fungal contamination within Portuguese elderly care centers. Fungi were measured using conventional as well as molecular methods in bedrooms, living rooms, canteens, storage areas, and outdoors. Bioaerosols were evaluated before and after the microenvironments' occupancy in order to understand the role played by occupancy in fungal contamination. Fungal load results varied from 32 colony-forming units CFU m(-3) in bedrooms to 228 CFU m(-3) in storage areas. Penicillium sp. was the most frequently isolated (38.1%), followed by Aspergillus sp. (16.3%) and Chrysonilia sp. (4.2%). With respect to Aspergillus genus, three different fungal species in indoor air were detected, with A. candidus (62.5%) the most prevalent. On surfaces, 40 different fungal species were isolated and the most frequent was Penicillium sp. (22.2%), followed by Aspergillus sp. (17.3%). Real-time polymerase chain reaction did not detect the presence of A. fumigatus complex. Species from Penicillium and Aspergillus genera were the most abundant in air and surfaces. The species A. fumigatus was present in 12.5% of all indoor microenvironments assessed. The living room was the indoor microenvironment with lowest fungal concentration and the storage area was highest.

Passive sampling methods for contaminated sediments: Risk assessment and management

PubMed Central

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

2014-01-01

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

Molecular modifications of cholesterol metabolism in the liver and the brain after chronic contamination with cesium 137.

PubMed

Racine, R; Grandcolas, L; Grison, S; Gourmelon, P; Guéguen, Y; Veyssière, G; Souidi, M

2009-07-01

Twenty years after Chernobyl accident, the daily ingestion of foodstuff grown on contaminated grounds remains the main source for internal exposure to ionizing radiations, and primarily to cesium 137 ((137)Cs). Though the effects of a long-term internal contamination with radionuclides are poorly documented, several non-cancerous pathologies have been described in this population. However, lipid metabolism was never investigated after chronic internal contamination although disturbances were observed in externally-exposed people. In this regard, we assessed the effects of a chronic ingestion of (137)Cs on hepatic and cerebral cholesterol metabolism. To mimic a chronically-exposed population, rats were given (137)Cs-supplemented water at a post-accidental dose (150 Bq/rat/day) during 9 months. The plasma profile, and brain and liver cholesterol concentrations were unchanged. A decrease of ACAT 2, Apo E, and LXRmRNA levels was recorded in the liver. In the brain, a decrease of CYP27A1 and ACAT 1 gene expression was observed. These results clearly show that cholesterol metabolism is not disrupted by a chronic ingestion of (137)Cs, although several molecular alterations are observed. This work would be interestingly completed by studying the influence of (137)Cs in models likely more sensitive to contaminants, such as the fetus or individuals susceptible to a lipidic disease.

Laser pattern generator challenges in airborne molecular contamination protection

NASA Astrophysics Data System (ADS)

Ekberg, Mats; Skotte, Per-Uno; Utterback, Tomas; Paul, Swaraj; Kishkovich, Oleg P.; Hudzik, James S.

2003-08-01

The introduction of photomask laser pattern generators presents new challenges to system designers and manufacturers. One of the laser pattern generator's environmental operating challenges is Airborne Molecular Contamination (AMC), which affects both chemically amplified resists (CAResist) and laser optics. Similar challenges in CAResist protection have already been addressed in semiconductor wafer lithography with reasonable solutions and experience gained by all those involved. However, photomask and photomask equipment manufacturers have not previously had a comparable experience, and some photomask AMC issues differ from those seen in semiconductor wafer lithography. Culminating years of AMC experience, the authors discuss specific requirements of Photomask AMC. Air sampling and material of construction analysis were performed to understand these particular AMC challenges and used to develop an appropriate filtration specification for different classes of contaminates. The authors portray the importance of cooperation between tool designers and AMC experts early in the design stage to assure goal attainment to maximize both process stability and machine productivity in advanced mask making. In conclusion, the authors provide valuable recommendations to both laser tool users and other equipment manufacturers.

ASSESSING FISH TISSUE CONTAMINATION ON A REGIONAL SCALE

EPA Science Inventory

The selection of target fish species for assessing the extent of fish tissue contaminants is a critical consideration in regional stream surveys such as the Environmental Monitoring and Assessment Program (EMAP). The ideal species would be widely distributed and common, bioaccumu...

Contamination assessment for OSSA space station IOC payloads

NASA Technical Reports Server (NTRS)

Wu, S. T.

1987-01-01

An assessment is made of NASA/OSSA space station IOC payloads. The report has two main objectives, i.e., to provide realistic contamination requirements for space station attached payloads, serviced payloads and platforms, and to determine unknowns or major impacts requiring further assessment.

Towards the assessment and management of contaminated dredged materials.

PubMed

Agius, Suzanne J; Porebski, Linda

2008-04-01

Environment Canada's Disposal at Sea Programme hosted the Contaminated Dredged Material Management Decisions Workshop in Montreal, Quebec, Canada, on 28-30 November 2006. The workshop brought together over 50 sediment assessment and management experts from academic, industrial, and regulatory backgrounds and charged them with drafting a potential framework to assess contaminated dredged materials and compare the risks of various disposal alternatives. This article summarizes the recommendations made during the workshop concerning the development of sediment assessment tools, the interpretation of these tools, and the essential attributes of a comparative risk assessment process. The major outcomes of the workshop include a strong recommendation to develop a national dredging or sediment management strategy, a potential decision-making framework for the assessment of dredged materials and comparative risk assessment of disposal options, and the expansion of minimum sediment characterization requirements for nonroutine disposal permit applications.

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

PubMed

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

2013-01-01

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

Long-Term Oil Contamination Alters the Molecular Ecological Networks of Soil Microbial Functional Genes

PubMed Central

Liang, Yuting; Zhao, Huihui; Deng, Ye; Zhou, Jizhong; Li, Guanghe; Sun, Bo

2016-01-01

With knowledge on microbial composition and diversity, investigation of within-community interactions is a further step to elucidate microbial ecological functions, such as the biodegradation of hazardous contaminants. In this work, microbial functional molecular ecological networks were studied in both contaminated and uncontaminated soils to determine the possible influences of oil contamination on microbial interactions and potential functions. Soil samples were obtained from an oil-exploring site located in South China, and the microbial functional genes were analyzed with GeoChip, a high-throughput functional microarray. By building random networks based on null model, we demonstrated that overall network structures and properties were significantly different between contaminated and uncontaminated soils (P < 0.001). Network connectivity, module numbers, and modularity were all reduced with contamination. Moreover, the topological roles of the genes (module hub and connectors) were altered with oil contamination. Subnetworks of genes involved in alkane and polycyclic aromatic hydrocarbon degradation were also constructed. Negative co-occurrence patterns prevailed among functional genes, thereby indicating probable competition relationships. The potential “keystone” genes, defined as either “hubs” or genes with highest connectivities in the network, were further identified. The network constructed in this study predicted the potential effects of anthropogenic contamination on microbial community co-occurrence interactions. PMID:26870020

Exposure assessment of process-related contaminants in food by biomarker monitoring

DOE PAGES

Rietjens, Ivonne M. C. M.; Dussort, P.; Gunther, Helmut; ...

2018-01-04

Exposure assessment is a fundamental part of the risk assessment paradigm, but can often present a number of challenges and uncertainties. This is especially the case for process contaminants formed during the processing, e.g. heating of food, since they are in part highly reactive and/or volatile, thus making exposure assessment by analysing contents in food unreliable. New approaches are therefore required to accurately assess consumer exposure and thus better inform the risk assessment. Such novel approaches may include the use of biomarkers, physiologically based kinetic (PBK) modelling-facilitated reverse dosimetry, and/or duplicate diet studies. This review focuses on the state ofmore » the art with respect to the use of biomarkers of exposure for the process contaminants acrylamide, 3-MCPD esters, glycidyl esters, furan and acrolein. From the overview presented, it becomes clear that the field of assessing human exposure to process-related contaminants in food by biomarker monitoring is promising and strongly developing. The current state of the art as well as the existing data gaps and challenges for the future were defined. They include (1) using PBK modelling and duplicate diet studies to establish, preferably in humans, correlations between external exposure and biomarkers; (2) elucidation of the possible endogenous formation of the process-related contaminants and the resulting biomarker levels; (3) the influence of inter-individual variations and how to include that in the biomarker-based exposure predictions; (4) the correction for confounding factors; (5) the value of the different biomarkers in relation to exposure scenario’s and risk assessment, and (6) the possibilities of novel methodologies. Here, in spite of these challenges it can be concluded that biomarker-based exposure assessment provides a unique opportunity to more accurately assess consumer exposure to process-related contaminants in food and thus to better inform risk assessment.« less

Exposure assessment of process-related contaminants in food by biomarker monitoring

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

Rietjens, Ivonne M. C. M.; Dussort, P.; Gunther, Helmut

Exposure assessment is a fundamental part of the risk assessment paradigm, but can often present a number of challenges and uncertainties. This is especially the case for process contaminants formed during the processing, e.g. heating of food, since they are in part highly reactive and/or volatile, thus making exposure assessment by analysing contents in food unreliable. New approaches are therefore required to accurately assess consumer exposure and thus better inform the risk assessment. Such novel approaches may include the use of biomarkers, physiologically based kinetic (PBK) modelling-facilitated reverse dosimetry, and/or duplicate diet studies. This review focuses on the state ofmore » the art with respect to the use of biomarkers of exposure for the process contaminants acrylamide, 3-MCPD esters, glycidyl esters, furan and acrolein. From the overview presented, it becomes clear that the field of assessing human exposure to process-related contaminants in food by biomarker monitoring is promising and strongly developing. The current state of the art as well as the existing data gaps and challenges for the future were defined. They include (1) using PBK modelling and duplicate diet studies to establish, preferably in humans, correlations between external exposure and biomarkers; (2) elucidation of the possible endogenous formation of the process-related contaminants and the resulting biomarker levels; (3) the influence of inter-individual variations and how to include that in the biomarker-based exposure predictions; (4) the correction for confounding factors; (5) the value of the different biomarkers in relation to exposure scenario’s and risk assessment, and (6) the possibilities of novel methodologies. Here, in spite of these challenges it can be concluded that biomarker-based exposure assessment provides a unique opportunity to more accurately assess consumer exposure to process-related contaminants in food and thus to better inform risk assessment.« less

Exposure assessment of process-related contaminants in food by biomarker monitoring.

PubMed

Rietjens, Ivonne M C M; Dussort, P; Günther, Helmut; Hanlon, Paul; Honda, Hiroshi; Mally, Angela; O'Hagan, Sue; Scholz, Gabriele; Seidel, Albrecht; Swenberg, James; Teeguarden, Justin; Eisenbrand, Gerhard

2018-01-01

Exposure assessment is a fundamental part of the risk assessment paradigm, but can often present a number of challenges and uncertainties. This is especially the case for process contaminants formed during the processing, e.g. heating of food, since they are in part highly reactive and/or volatile, thus making exposure assessment by analysing contents in food unreliable. New approaches are therefore required to accurately assess consumer exposure and thus better inform the risk assessment. Such novel approaches may include the use of biomarkers, physiologically based kinetic (PBK) modelling-facilitated reverse dosimetry, and/or duplicate diet studies. This review focuses on the state of the art with respect to the use of biomarkers of exposure for the process contaminants acrylamide, 3-MCPD esters, glycidyl esters, furan and acrolein. From the overview presented, it becomes clear that the field of assessing human exposure to process-related contaminants in food by biomarker monitoring is promising and strongly developing. The current state of the art as well as the existing data gaps and challenges for the future were defined. They include (1) using PBK modelling and duplicate diet studies to establish, preferably in humans, correlations between external exposure and biomarkers; (2) elucidation of the possible endogenous formation of the process-related contaminants and the resulting biomarker levels; (3) the influence of inter-individual variations and how to include that in the biomarker-based exposure predictions; (4) the correction for confounding factors; (5) the value of the different biomarkers in relation to exposure scenario's and risk assessment, and (6) the possibilities of novel methodologies. In spite of these challenges it can be concluded that biomarker-based exposure assessment provides a unique opportunity to more accurately assess consumer exposure to process-related contaminants in food and thus to better inform risk assessment.

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

ASSESSING POTENTIAL EXPOSURES FROM ROUTINE USE OF VOC-CONTAMINATED GROUNDWATER

EPA Science Inventory

Three identical experiments were conducted in a single residence to assess potential exposures that may result from the routine household use of VOC-contaminated groundwater. Each experiment was based on a single 20-min shower using contaminated groundwater containing 185-367 ug/...

Flight measurement of molecular contaminant deposition

NASA Astrophysics Data System (ADS)

Hall, David F.

1994-10-01

A spacecraft was instrumented with four temperature controlled quartz crystal microbalance (TQCM) contamination detectors. One TQCM, located inside the vehicle, recorded contaminant deposition that was orders of magnitude higher than did the three TQCMs located in various positions outside the vehicle. The deposition rate on the interior TQCM varied with the temperatures of interior spacecraft cavity surfaces. In particular, there is clear evidence of condensation on these surfaces and re-evaporation from these surfaces by previously outgassed contaminant molecules. The e-folding time constants of the deposition on two of the exterior TQCMs held at -50 degree(s)C are approximately 1.4 years, with extrapolated final equivalent thickness of the deposition in the 20 - 25 nm (200 - 250 angstroms) range. The third exterior TQCM, which has a significant field of view of a segmented thermal blanket, collected contamination at a greater rate. The data enable the ranking of the several contamination transport mechanisms at work and the drawing of general recommendations for spacecraft design.

Decision support methods for the environmental assessment of contamination at mining sites.

PubMed

Jordan, Gyozo; Abdaal, Ahmed

2013-09-01

Polluting mine accidents and widespread environmental contamination associated with historic mining in Europe and elsewhere has triggered the improvement of related environmental legislation and of the environmental assessment and management methods for the mining industry. Mining has some unique features such as natural background pollution associated with natural mineral deposits, industrial activities and contamination located in the three-dimensional sub-surface space, the problem of long-term remediation after mine closure, problem of secondary contaminated areas around mine sites and abandoned mines in historic regions like Europe. These mining-specific problems require special tools to address the complexity of the environmental problems of mining-related contamination. The objective of this paper is to review and evaluate some of the decision support methods that have been developed and applied to mining contamination. In this paper, only those methods that are both efficient decision support tools and provide a 'holistic' approach to the complex problem as well are considered. These tools are (1) landscape ecology, (2) industrial ecology, (3) landscape geochemistry, (4) geo-environmental models, (5) environmental impact assessment, (6) environmental risk assessment, (7) material flow analysis and (8) life cycle assessment. This unique inter-disciplinary study should enable both the researcher and the practitioner to obtain broad view on the state-of-the-art of decision support methods for the environmental assessment of contamination at mine sites. Documented examples and abundant references are also provided.

ASSESSMENT OF RADIOACTIVE AND NON-RADIOACTIVE CONTAMINANTS FOUND IN LOW LEVEL RADIOACTIVE WASTE STREAMS

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

R.H. Little, P.R. Maul, J.S.S. Penfoldag

2003-02-27

This paper describes and presents the findings from two studies undertaken for the European Commission to assess the long-term impact upon the environment and human health of non-radioactive contaminants found in various low level radioactive waste streams. The initial study investigated the application of safety assessment approaches developed for radioactive contaminants to the assessment of nonradioactive contaminants in low level radioactive waste. It demonstrated how disposal limits could be derived for a range of non-radioactive contaminants and generic disposal facilities. The follow-up study used the same approach but undertook more detailed, disposal system specific calculations, assessing the impacts of bothmore » the non-radioactive and radioactive contaminants. The calculations undertaken indicated that it is prudent to consider non-radioactive, as well as radioactive contaminants, when assessing the impacts of low level radioactive waste disposal. For some waste streams with relatively low concentrations of radionuclides, the potential post-closure disposal impacts from non-radioactive contaminants can be comparable with the potential radiological impacts. For such waste streams there is therefore an added incentive to explore options for recycling the materials involved wherever possible.« less

Colloidal crystal templated molecular imprinted polymer for the detection of 2-butoxyethanol in water contaminated by hydraulic fracturing.

PubMed

Dai, Jingjing; Vu, Danh; Nagel, Susan; Lin, Chung-Ho; Fidalgo de Cortalezzi, Maria

2017-12-06

The authors describe a molecularly imprinted polymer (MIP) that enables detection of 2-butoxyethanol (2BE), a pollutant associated with hydraulic fracturing contamination. Detection is based on a combination of a colloidal crystal templating and a molecular imprinting. The MIPs are shown to display higher binding capacity for 2BE compared to non-imprinted films (NIPs), with imprinting efficiencies of ∼ 2. The tests rely on the optical effects that are displayed by the uniformly ordered porous structure of the material. The reflectance spectra of the polymer films have characteristic Bragg peaks whose location varies with the concentration of 2BE. Peaks undergo longwave red shifts up to 50 nm on exposure of the MIP to 2BE in concentrations in the range from 1 ppb to 100 ppm. This allows for quantitative estimates of the 2BE concentrations present in aqueous solutions. The material is intended for use in the early detection of contamination at hydraulic fracturing sites. Graphical abstract Molecularly imprinted polymers (MIPs) sensor with the sensing ability on reflectance spectra responding to the presence of 2-butoxyethanol (2BE) for early detection of hydraulic fracking contamination.

The Molecular Biology Capstone Assessment: A Concept Assessment for Upper-Division Molecular Biology Students

ERIC Educational Resources Information Center

Couch, Brian A.; Wood, William B.; Knight, Jennifer K.

2015-01-01

Measuring students' conceptual understandings has become increasingly important to biology faculty members involved in evaluating and improving departmental programs. We developed the Molecular Biology Capstone Assessment (MBCA) to gauge comprehension of fundamental concepts in molecular and cell biology and the ability to apply these concepts in…

Application of computer-assisted molecular modeling for immunoassay of low molecular weight food contaminants: A review.

PubMed

Xu, Zhen-Lin; Shen, Yu-Dong; Beier, Ross C; Yang, Jin-Yi; Lei, Hong-Tao; Wang, Hong; Sun, Yuan-Ming

2009-08-11

Immunoassay for low molecular weight food contaminants, such as pesticides, veterinary drugs, and mycotoxins is now a well-established technique which meets the demand for a rapid, reliable, and cost-effective analytical method. However, due to limited understanding of the molecular structure of antibody binding sites and antigenic epitopes, as well as the intermolecular binding forces that come into play, the traditional 'trial and error' method used to develop antibodies still remains the method of choice. Therefore, development of enhanced immunochemical techniques for specific- and generic-assays, requires new approaches for antibody design that will improve affinity and specificity of the antibody in a more rapid and economic manner. Computer-assisted molecular modeling (CAMM) has been demonstrated to be a useful tool to help the immunochemist develop immunoassays. CAMM methods can be used to help direct improvements to important antibody features, and can provide insights into the effects of molecular structure on biological activity that are difficult or impossible to obtain in any other way. In this review, we briefly summarize applications of CAMM in immunoassay development, including assisting in hapten design, explaining cross-reactivity, modeling antibody-antigen interactions, and providing insights into the effects of the mouse body temperature on the three-dimensional conformation of a hapten during antibody production. The fundamentals and theory, programs and software, limitations, and prospects of CAMM in immunoassay development were also discussed.

Human health risk assessment related to contaminated land: state of the art.

PubMed

Swartjes, F A

2015-08-01

Exposure of humans to contaminants from contaminated land may result in many types of health damage ranging from relatively innocent symptoms such as skin eruption or nausea, on up to cancer or even death. Human health protection is generally considered as a major protection target. State-of-the-art possibilities and limitations of human health risk assessment tools are described in this paper. Human health risk assessment includes two different activities, i.e. the exposure assessment and the hazard assessment. The combination of these is called the risk characterization, which results in an appraisal of the contaminated land. Exposure assessment covers a smart combination of calculations, using exposure models, and measurements in contact media and body liquids and tissue (biomonitoring). Regarding the time frame represented by exposure estimates, biomonitoring generally relates to exposure history, measurements in contact media to actual exposures, while exposure calculations enable a focus on exposure in future situations. The hazard assessment, which is different for contaminants with or without a threshold for effects, results in a critical exposure value. Good human health risk assessment practice accounts for tiered approaches and multiple lines of evidence. Specific attention is given here to phenomena such as the time factor in human health risk assessment, suitability for the local situation, background exposure, combined exposure and harmonization of human health risk assessment tools.

Molecular Contamination on Anodized Aluminum Components of the Genesis Science Canister

NASA Technical Reports Server (NTRS)

Burnett, D. S.; McNamara, K. M.; Jurewicz, A.; Woolum, D.

2005-01-01

Inspection of the interior of the Genesis science canister after recovery in Utah, and subsequently at JSC, revealed a darkening on the aluminum canister shield and other canister components. There has been no such observation of film contamination on the collector surfaces, and preliminary spectroscopic ellipsometry measurements support the theory that the films observed on the anodized aluminum components do not appear on the collectors to any significant extent. The Genesis Science Team has made an effort to characterize the thickness and composition of the brown stain and to determine if it is associated with molecular outgassing.Detailed examination of the surfaces within the Genesis science canister reveals that the brown contamination is observed to varying degrees, but only on surfaces exposed in space to the Sun and solar wind hydrogen. In addition, the materials affected are primarily composed of anodized aluminum. A sharp line separating the sun and shaded portion of the thermal closeout panel is shown. This piece was removed from a location near the gold foil collector within the canister. Future plans include a reassembly of the canister components to look for large-scale patterns of contamination within the canister to aid in revealing the root cause.

[Establishment of Assessment Method for Air Bacteria and Fungi Contamination].

PubMed

Zhang, Hua-ling; Yao, Da-jun; Zhang, Yu; Fang, Zi-liang

2016-03-15

In this paper, in order to settle existing problems in the assessment of air bacteria and fungi contamination, the indoor and outdoor air bacteria and fungi filed concentrations by impact method and settlement method in existing documents were collected and analyzed, then the goodness of chi square was used to test whether these concentration data obeyed normal distribution at the significant level of α = 0.05, and combined with the 3σ principle of normal distribution and the current assessment standards, the suggested concentrations ranges of air microbial concentrations were determined. The research results could provide a reference for developing air bacteria and fungi contamination assessment standards in the future.

Spacecraft external molecular contamination analysis

NASA Technical Reports Server (NTRS)

Ehlers, H. K. F.

1990-01-01

Control of contamination on and around spacecraft is required to avoid adverse effects on the performance of instruments and spacecraft systems. Recent work in this area is reviewed and discussed. Specific issues and limitations to be considered as part of the effort to predict contamination effects using modeling techniques are addressed. Significant results of Space Shuttle missions in the field of molecule/surface interactions as well as their implications for space station design and operation are reviewed.

Assessing the bioavailability and risk from metal-contaminated soils and dusts

EPA Science Inventory

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, contaminat...

Biochemical markers for the assessment of aquatic environment contamination

PubMed Central

Havelková, Marcela; Randák, Tomáš; Blahová, Jana; Slatinská, Iveta; Svobodová, Zdeňka

2008-01-01

The need for assessment of aquatic ecosystem contamination and of its impact on water dwelling organisms was developed in response to rising aquatic environmental pollution. In this field study, liver enzymes of phase I and phase II of xenobiotic transformation, namely cytochrome P450, ethoxyresorufin-O-deethylase, glutathione-S-transferase and tripeptide glutathione were used to assess the contamination of the aquatic environment at different rivers in the Czech Republic. The indicator species selected was the male chub (Leuciscus cephalus L.) and male brown trout (Salmo trutta fario). Chemical analyses included also the assessment of the most important inductors of previously mentioned biochemical markers. The major inductors of monitored biomarkers are industrial contaminants which belong to a large group of organic pollutants (PCB, PAH, PCDD/F, DDT, HCH, HCB and OCS), persistent in the environment. Four different groups of river basins were assessed: the River Tichá Orlice and its tributary the Kralický brook; important tributaries of the River Elbe (the rivers Orlice, Chrudimka, Cidlina, Jizera, Vltava, Ohře and Bílina); major rivers in the Czech Republic (the rivers Lužnice, Otava, Sázava, Berounka, Vltava, Labe, Ohře, Svratka, Dyje, Morava and Odra) and the River Vltava. The use of the biochemical markers together with chemical analyses seems to be an effective way to monitor the quality of aquatic environment. PMID:21218108

Assessing the bioavailability and risk from metal contaminated soils and dusts#

EPA Science Inventory

Exposure to contaminated soil and dust is an important pathway in human and ecological risk assessment and often is the "risk-driver" for metal contaminated soil. Site-specific soil physical and chemical characteristics, as well as biological factors, determine the bioavailabilit...

Incorporating Contaminant Bioavailability into Sediment Quality Assessment Frameworks

EPA Science Inventory

The recently adopted sediment quality assessment framework for evaluating bay and estuarine sediments in the State of California incorporates bulk sediment chemistry as a key line of evidence(LOE) but does not address the bioavailability of measured contaminants. Thus, the chemis...

Risk assessment for chemical pickling of metals contaminated by radioactive materials.

PubMed

Donzella, A; Formisano, P; Giroletti, E; Zenoni, A

2007-01-01

In recent years, many cases of contamination of metal scraps by unwanted radioactive materials have occurred. Moreover, international organisations are evaluating the possibility to re-use or to recycle metals coming from nuclear power plants. The metal recycling industry has started to worry about radiation exposure of workers that could be in contact with contaminated metals during each manufacturing phase. Risks are strongly dependent on the radiation source features. The aim of this study is to perform risk assessment for workers involved in chemical pickling of steel coils. Monte Carlo simulations have been performed, using the MCNP package and considering coils contaminated with (60)Co, (137)Cs, (241)Am and (226)Ra. Under the most conservative conditions (coil contaminated with 1.0 kBq g(-1) of (60)Co), the dose assessment results lower than the European dose limit for the population (1 mSv y(-1)), considering a maximum number of 10 contaminated coils handled per year. The only exception concerns the case of (241)Am, for which internal contamination could be non- negligible and should be verified in the specific cases. In every case, radiation exposure risk for people standing at 50 m from the coil is widely <1 mSv y(-1).

Multiple correspondence analysis and random amplified polymorphic DNA molecular typing to assess the sources of Staphylococcus aureus contamination in alheira production lines.

PubMed

Esteves, A; Patarata, L; Aymerich, T; Garriga, M; Martins, C

2007-03-01

Sources and tracing of Staphylococcus aureus in alheira (garlic sausage) production were evaluated by multifactorial correspondence analysis (MCA) of occurrence data and a random amplified polymorphic DNA (RAPD) on S. aureus isolates. Samples from four production lines, four different production batches, and 14 different sampling sites (including raw material, different contact surfaces, and several stages of alheira manufacturing) were analyzed at four sampling times. From the 896 microbial analyses completed, a collection of 170 S. aureus isolates was obtained. Although analysis of the occurrence data alone was not elucidative enough, MCA and RAPD-PCR were able to assess the sources of contamination and to trace the spread of this microorganism along the production lines. MCA results indicated that the presence of S. aureus in alheira was related to its presence in the intermediate manufacturing stages after heat treatment but before stuffing in the casings. It was also possible to associate a cross-contamination path related to handler procedures. RAPD-PCR typing in accordance to MCA results confirmed the cross-contamination path between the raw material and casings and the role of handlers as an important cross-contamination vehicle.

Nitrate contamination risk assessment in groundwater at regional scale

NASA Astrophysics Data System (ADS)

Daniela, Ducci

2016-04-01

Nitrate groundwater contamination is widespread in the world, due to the intensive use of fertilizers, to the leaking from the sewage network and to the presence of old septic systems. This research presents a methodology for groundwater contamination risk assessment using thematic maps derived mainly from the land-use map and from statistical data available at the national institutes of statistic (especially demographic and environmental data). The potential nitrate contamination is considered as deriving from three sources: agricultural, urban and periurban. The first one is related to the use of fertilizers. For this reason the land-use map is re-classified on the basis of the crop requirements in terms of fertilizers. The urban source is the possibility of leaks from the sewage network and, consequently, is linked to the anthropogenic pressure, expressed by the population density, weighted on the basis of the mapped urbanized areas of the municipality. The periurban sources include the un-sewered areas, especially present in the periurban context, where illegal sewage connections coexist with on-site sewage disposal (cesspools, septic tanks and pit latrines). The potential nitrate contamination map is produced by overlaying the agricultural, urban and periurban maps. The map combination process is very easy, being an algebraic combination: the output values are the arithmetic average of the input values. The groundwater vulnerability to contamination can be assessed using parametric methods, like DRASTIC or easier, like AVI (that involves a limited numbers of parameters). In most of cases, previous documents produced at regional level can be used. The pollution risk map is obtained by combining the thematic maps of the potential nitrate contamination map and the groundwater contamination vulnerability map. The criterion for the linkages of the different GIS layers is very easy, corresponding to an algebraic combination. The methodology has been successfully

Assessing Organic Contaminant Fluxes from Contaminated Sediments Following Dam Removal in an Urbanized River

EPA Science Inventory

In this study, methods and approaches were developed and tested to assess changes in contaminant fluxes resulting from dam removal in a riverine system. Sediment traps and passive samplers were deployed to measure particulate and dissolved PAHs and PCBs in the water column prior...

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.

Status and Assessment of Chesapeake Bay Wildlife Contamination

USGS Publications Warehouse

Heinz, G.H.; Wiemeyer, Stanley N.; Clark, D.R.; Albers, P.H.; Henry, P.; Batiuk, R.A.

1992-01-01

As an integral component of its priority setting process, the Chesapeake Bay Program`s Toxics Subcommittee has sought the expertise of Chesapeake Bay researchers and managers in developing a series of Chesapeake Bay toxics status and assessment papers. In the report, evidence for historical and current contaminant effects on key bird species, mammals, reptiles and amphibians which inhabit the Chesapeake Bay basin is examined. For each group of wildlife species, a general overview of effects caused by specific toxic substances is followed by detailed accounts of contaminant effects on selected species. Sponsored by Environmental Protection Agency, Annapolis, MD. Chesapeake Bay Program.

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

ASSESSING ALLERGENICITY OF INDOOR AIR FUNGAL CONTAMINANTS

EPA Science Inventory

Assessing Allergenicity of Indoor Air Fungal Contaminants
M D W Ward1, M E Viana2, N Haykal-Coates1, L B Copeland1, S H Gavett1, and MJ K Selgrade1. 1US EPA, ORD, NHEERL, RTP, NC, USA. 2NCSU, CVM, Raleigh, NC, USA.
Rationale: The indoor environment has increased in impor...

Toxicological assessment of aquatic ecosystems: application to watercraft contaminants in shallow water environments

USGS Publications Warehouse

Winger, P.V.; Kemmish, Michael J.

2002-01-01

Recreational boating and personal watercraft use have the potential to adversely impact shallow water systems through contaminant release and physical disturbance of bottom sediments. These nearshore areas are often already degraded by surface runoff, municipal and industrial effluents, and other anthropogenic activities. For proper management, information is needed on the level of contamination and environmental quality of these systems. A number of field and laboratory procedures can be used to provide this much needed information. Contaminants, such as metals, pesticides, polychlorinated biphenyls and polycyclic aromatic hydrocarbons, entering aquatic environments generally attach to particulate matter that eventually settles and becomes incorporated into the bottom sediments. Because bottom sediments serve as a sink and as a source for contaminants, environmental assessments generally focus on this matrix. While contaminant residues in sediments and sediment pore waters can reflect environmental quality, characteristics of sediment (redox potential, sediment/pore-water chemistry, acid volatile sulfides, percent organic matter, and sediment particle size) influence their bioavailability and make interpretation of environmental significance difficult. Comparisons of contaminant concentrations in pore water (interstitial water) and sediment with water quality criteria and sediment quality guidelines, respectively, can provide insight into potential biological effects. Laboratory bioaccumulation studies and residue concentrations in resident or caged biota also yield information on potential biological impacts. The usefulness of these measurements may increase as data are developed relating in-situ concentrations, tissue residue levels, and biological responses. Exposure of test organisms in situ or to field-collected sediment and pore water are additional procedures that can be used to assess the biological effects of contaminants. A battery of tests using multi

Assessing organic contaminant fluxes from contaminated sediments following dam removal in an urbanized river.

PubMed

Cantwell, Mark G; Perron, Monique M; Sullivan, Julia C; Katz, David R; Burgess, Robert M; King, John

2014-08-01

In this study, methods and approaches were developed and tested to assess changes in contaminant fluxes resulting from dam removal in a riverine system. Sediment traps and passive samplers were deployed to measure particulate and dissolved polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in the water column prior to and following removal of a small, low-head dam in the Pawtuxet River, an urbanized river located in Cranston, RI, USA. During the study, concentrations of particulate and dissolved PAHs ranged from 21.5 to 103 μg/g and from 68 to 164 ng/L, respectively. Overall, temporal trends of PAHs showed no increases in either dissolved or particulate phases following removal of the dam. Dissolved concentrations of PCBs were very low, remaining below 1.72 ng/L at all sites. Particulate PCB concentrations across sites and time showed slightly greater variability, ranging from 80 to 469 ng/g, but with no indication that dam removal influenced any increases. Particulate PAHs and PCBs were sampled continuously at the site located below the dam and did not show sustained increases in concentration resulting from dam removal. The employment of passive sampling technology and sediment traps was highly effective in monitoring the concentrations and flux of contaminants moving through the river system. Variations in river flow had no effect on the concentration of contaminants in the dissolved or particulate phases, but did influence the flux rate of contaminants exiting the river. Overall, dam removal did not cause measurable sediment disturbance or increase the concentration or fluxes of dissolved or particulate PAHs and PCBs. This is due in large part to low volumes of impounded sediment residing above the dam and highly armored sediments in the river channel, which limited erosion. Results from this study will be used to improve methods and approaches that assess the short- and long-term impacts ecological restoration activities such as

Effect of heavy metals and organic matter on root exudates (low molecular weight organic acids) of herbaceous species: An assessment in sand and soil conditions under different levels of contamination.

PubMed

Montiel-Rozas, M M; Madejón, E; Madejón, P

2016-09-01

Bioavailability of heavy metals can be modified by different root exudates. Among them, low molecular weight organic acids (LMWOAs) play an important role in this process. Three plant species (Poa annua, Medicago polymorpha and Malva sylvestris), potentially used for phytoremediation, have been assessed for both metal uptake and LMWOAs excretion in contaminated environments with different concentrations of Cd, Cu and Zn. The experiments have been carried out in washed sand and in three contaminated soils where two organic amendments were added (biosolid compost and alperujo compost). The most abundant LMWOAs excreted by all studied plants were oxalic and malic acids, although citric and fumaric acids were also detected. The general tendency was that plants responded to an increase of heavy metal stress releasing higher amounts of LMWOAs. This is an efficient exclusion mechanism reducing the metal uptake and allowing the plant growth at high levels of contamination. In the experiment using wash sand as substrate, the organic acids composition and quantity depended mainly on plant species and metal contamination. M. polymorpha was the species that released the highest concentrations of LMWOAs, both in sand and in soils with no amendment addition, whereas a decrease of these acids was observed with the addition of amendments. Our results established a clear effect of organic matter on the composition and total amount of LMWOAs released. The increase of organic matter and nutrients, through amendments, improved the soil quality reducing phytotoxicity. As a result, organic acids exudates decreased and were solely composed of oxalic acid (except for M. polymorpha). The release of LMWOAs has proved to be an important mechanism against heavy metal stress, unique to each species and modifiable by means of organic amendment addition. Copyright © 2016 Elsevier Ltd. All rights reserved.

Molecularly Imprinted Polymer as an Antibody Substitution in Pseudo-immunoassays for Chemical Contaminants in Food and Environmental Samples.

PubMed

Chen, Chaochao; Luo, Jiaxun; Li, Chenglong; Ma, Mingfang; Yu, Wenbo; Shen, Jianzhong; Wang, Zhanhui

2018-03-21

The chemical contaminants in food and the environment are quite harmful to food safety and human health. Rapid, accurate, and cheap detection can effectively control the potential risks derived from these chemical contaminants. Among all detection methods, the immunoassay based on the specific interaction of antibody-analyte is one of the most widely used techniques in the field. However, biological antibodies employed in the immunoassay usually cannot tolerate extreme conditions, resulting in an unstable state in both physical and chemical profiles. Molecularly imprinted polymers (MIPs) are a class of polymers with specific molecular recognition abilities, which are highly robust, showing excellent operational stability under a wide variety of conditions. Recently, MIPs have been used in biomimetic immunoassays for chemical contaminants as an antibody substitute in food and the environment. Here, we reviewed these applications of MIPs incorporated in different analytical platforms, such as enzyme-linked immunosorbent assay, fluorescent immunoassay, chemiluminescent immunoassay, electrochemical immunoassay, microfluidic paper-based immunoassay, and homogeneous immunoassay, and discussed current challenges and future trends in the use of MIPs in biomimetic immunoassays.

Toxicity assessment for petroleum-contaminated soil using terrestrial invertebrates and plant bioassays.

PubMed

Hentati, Olfa; Lachhab, Radhia; Ayadi, Mariem; Ksibi, Mohamed

2013-04-01

The assessment of soil quality after a chemical or oil spill and/or remediation effort may be measured by evaluating the toxicity of soil organisms. To enhance our understanding of the soil quality resulting from laboratory and oil field spill remediation, we assessed toxicity levels by using earthworms and springtails testing and plant growth experiments. Total petroleum hydrocarbons (TPH)-contaminated soil samples were collected from an oilfield in Sfax, Tunisia. Two types of bioassays were performed. The first assessed the toxicity of spiked crude oil (API gravity 32) in Organization for Economic Co-operation and Development artificial soil. The second evaluated the habitat function through the avoidance responses of earthworms and springtails and the ability of Avena sativa to grow in TPH-contaminated soils diluted with farmland soil. The EC50 of petroleum-contaminated soil for earthworms was 644 mg of TPH/kg of soil at 14 days, with 67 % of the earthworms dying after 14 days when the TPH content reached 1,000 mg/kg. The average germination rate, calculated 8 days after sowing, varied between 64 and 74 % in low contaminated soils and less than 50 % in highly contaminated soils.

Assessing the Impact of Source-Zone Remediation Efforts at the Contaminant-Plume Scale Through Analysis of Contaminant Mass Discharge

PubMed Central

Brusseau, M. L.; Hatton, J.; DiGuiseppi, W.

2011-01-01

The long-term impact of source-zone remediation efforts was assessed for a large site contaminated by trichloroethene. The impact of the remediation efforts (soil vapor extraction and in-situ chemical oxidation) was assessed through analysis of plume-scale contaminant mass discharge, which was measured using a high-resolution data set obtained from 23 years of operation of a large pump-and-treat system. The initial contaminant mass discharge peaked at approximately 7 kg/d, and then declined to approximately 2 kg/d. This latter value was sustained for several years prior to the initiation of source-zone remediation efforts. The contaminant mass discharge in 2010, measured several years after completion of the two source-zone remediation actions, was approximately 0.2 kg/d, which is ten times lower than the value prior to source-zone remediation. The time-continuous contaminant mass discharge data can be used to evaluate the impact of the source-zone remediation efforts on reducing the time required to operate the pump-and-treat system, and to estimate the cost savings associated with the decreased operational period. While significant reductions have been achieved, it is evident that the remediation efforts have not completely eliminated contaminant mass discharge and associated risk. Remaining contaminant mass contributing to the current mass discharge is hypothesized to comprise poorly-accessible mass in the source zones, as well as aqueous (and sorbed) mass present in the extensive lower-permeability units located within and adjacent to the contaminant plume. The fate of these sources is an issue of critical import to the remediation of chlorinated-solvent contaminated sites, and development of methods to address these sources will be required to achieve successful long-term management of such sites and to ultimately transition them to closure. PMID:22115080

A risk assessment approach to contaminants in Port Curtis, Queensland, Australia.

PubMed

Jones, Mary-Anne; Stauber, Jenny; Apte, Simon; Simpson, Stuart; Vicente-Beckett, Vicky; Johnson, Rod; Duivenvoorden, Leo

2005-01-01

Port Curtis is one of Australia's leading ports for which substantial industrial expansion is proposed over the next decade. However, there has been little attempt to date to assess the extent of contamination in waters, sediments and biota or to characterize the potential impacts of contaminants on aquatic biota. Contaminants of potential concern to biota and human health were investigated in the Port Curtis estuary using a screening-level risk assessment approach. Dissolved metal concentrations in waters were below [ANZECC/ARMCANZ, 2000. Australian and New Zealand Guidelines for Fresh and Marine Water Quality, Vol. 1. The Guidelines, Australian and New Zealand Environment and Conservation Council and Agriculture and Resource Management Council of Australia and New Zealand] trigger values, suggesting low risk of these contaminants. In sediments, arsenic, nickel and chromium concentrations exceeded interim sediment quality guidelines-low (ISQG-low), but were also high in the reference zone suggesting a natural origin. Historical data on naphthalene in Harbour sediments showed that it was also of potential concern. Bioaccumulation of contaminants in a range of biota was also used as an indicator of contaminant exposure. Biota were generally enriched in metals and tributyltin, which was also elevated in water and sediments. Although not unique to Port Curtis, mercury in barramundi was identified as a potential risk to human health.

The use of passive membrane samplers to assess organic contaminant inputs at five coastal sites in west Maui, Hawaii

USGS Publications Warehouse

Campbell, Pamela L.; Prouty, Nancy G.; Storlazzi, Curt; D'antonio, Nicole

2017-07-26

Five passive membrane samplers were deployed for 28 continuous days at select sites along and near the west Maui coastline to assess organic compounds and contaminant inputs to diverse, shallow coral reef ecosystems. Daily and weekly fluctuations in such inputs were captured on the membranes using integrative sampling. The distribution of organic compounds observed at these five coastal sites showed considerable variation; with high concentrations of terrestrially sourced organic compounds such as C29 sterols and high molecular weight n-alkanes at the strongly groundwater-influenced Kahekili vent site. In comparison, the coastal sites were presumably influenced more by seasonal surface and stream water runoff and therefore had marine-sourced organic compounds and fewer pharmaceuticals and personal care products. The direct correlation to upstream land-use practices was not obvious and may require additional wet-season sampling. Pharmaceuticals and personal care products as well as flame retardants were detected at all sites, and the Kahekili vent site had the highest number of detections. Planned future work must also determine the organic compound and contaminant concentrations adsorbed onto water column particulate matter, because it may also be an important vector for contaminant transport to coral reef ecosystems. The impact of contaminants per individual (such as fecundity and metabolism) as well as per community (such as species abundance and diversity) is necessary for an accurate assessment of environmental stress. Results presented herein provide current contaminant inputs to select nearshore environments along the west Maui coastline captured during the dry season, and they can be useful to aid potential future evaluations and (or) comparisons.

Assessment of chloroethene biodegradation in the subsurface by microbiological, molecular and isotopic tools

NASA Astrophysics Data System (ADS)

Schmidt, K. R.; Kranzioch, I.; Heidinger, M.; Ertl, S.; Tiehm, A.

2012-04-01

A multiple lines of evidence approach to assess the biodegradation potential of contaminated sites includes - site investigation analysing pollutant distribution (compounds, concentrations, isotopic composition) and hydrochemical conditions (redox conditions) - determination of the presence of pollutant degrading bacteria in the field by microbiological (most probable number, MPN) and molecular (polymerase chain reaction, PCR) methods - analysis of degradation processes in the laboratory by microcosms with determination of site specific isotopic enrichment factors enabling the quantification of biodegradation processes in the field. Results will be shown of the application of such a multiple lines of evidence approach at a chloroethene-contaminated site in Frankenthal, Germany. In anaerobic groundwater microcosms, reductive transformation of perchloroethene (PCE) and trichloroethene (TCE) was observed to mainly proceed to cis-1,2-dichloroethene (cDCE). 16S-PCR analysis showed a wide distribution of halorespiring bacteria capable of PCE degradation to cDCE, whereas Dehalococcoides - the only organisms described so far being able of complete reductive dechlorination down to ethene - was only found in one groundwater sample. Aerobic microcosms showed metabolic degradation of the lower chlorinated compounds cDCE and vinyl chloride (VC). Co-metabolic degradation of cDCE with VC as auxiliary substrate occurred, too. Significant stable carbon isotope fractionation was observed during anaerobic degradation of PCE and TCE as well as during aerobic degradation of cDCE and VC. Compiling the results of the different assessment methods, sequential dechlorination - PCE/TCE to cDCE anaerobically and cDCE to CO2 aerobically - was demonstrated to occur at the Frankenthal site. The extent of biodegradation in the field was calculated based on the enrichment factors determined in microcosms and the 13C-isotopic composition of the contaminants on site. The application of molecular

The Molecular Biology Capstone Assessment: A Concept Assessment for Upper-Division Molecular Biology Students

PubMed Central

Couch, Brian A.; Wood, William B.; Knight, Jennifer K.

2015-01-01

Measuring students’ conceptual understandings has become increasingly important to biology faculty members involved in evaluating and improving departmental programs. We developed the Molecular Biology Capstone Assessment (MBCA) to gauge comprehension of fundamental concepts in molecular and cell biology and the ability to apply these concepts in novel scenarios. Targeted at graduating students, the MBCA consists of 18 multiple-true/false (T/F) questions. Each question consists of a narrative stem followed by four T/F statements, which allows a more detailed assessment of student understanding than the traditional multiple-choice format. Questions were iteratively developed with extensive faculty and student feedback, including validation through faculty reviews and response validation through student interviews. The final assessment was taken online by 504 students in upper-division courses at seven institutions. Data from this administration indicate that the MBCA has acceptable levels of internal reliability (α = 0.80) and test–retest stability (r = 0.93). Students achieved a wide range of scores with a 67% overall average. Performance results suggest that students have an incomplete understanding of many molecular biology concepts and continue to hold incorrect conceptions previously documented among introductory-level students. By pinpointing areas of conceptual difficulty, the MBCA can provide faculty members with guidance for improving undergraduate biology programs. PMID:25713098

Contamination of the GOES-K filter wheel cooler

NASA Astrophysics Data System (ADS)

Sanders, Jack T., Jr.; Rosecrans, Glenn P.

1998-10-01

The Geostationary Operational Environmental Satellite (GOES) Sounder instrument uses radiant coolers to reduce the operating temperature of the detectors and filter wheel. GOES resides in an equatorial orbit 36,000 kilometers above the earth, and is stationary with respect to it. During the year, all sides of the spacecraft are exposed to the sun; the filter wheel emitter and detector radiators must be shielded form it to adequately cooled these components for nominal operations.Mirror Optical Solar Reflectors are used too reject sunlight before it can strike the radiators. Molecular outgassing from the Sounder instrument cavity, the filter wheel module, and the Sounder vacuum cooler housing have been demonstrated through mass transport modeling to contaminate the filter wheel sunshield panels during the in- orbit Radiant Cooler bakeout. Excessive molecular and particulate contamination can increase solar energy scatter, increase thermal emittance, and increase solar absorptance; all of which can increase the temperature of the components they serve, thus degrading nominal operations. After the GOES-K spacecraft thermal vacuum test, a haze was observed on and around the entrance aperture, and on the inside faces the filter wheel cooler sunshield. This paper documents the inspections, testing, and analysis used to: a) locate the likely sources for the contaminants, b) predict molecular contaminant accumulation on the filter wheel sunshields during the in-orbit bakeout, c) estimate the thermal effects from molecular build-up, and d) assess proposed hardware modifications and show the selection rationale used to maintain functionality for the GOES-K Sounder instrument.

Assessing soil and groundwater contamination in a metropolitan redevelopment project.

PubMed

Yun, Junki; Lee, Ju Young; Khim, Jeehyeong; Ji, Won Hyun

2013-08-01

The purpose of this study was to assess contaminated soil and groundwater for the urban redevelopment of a rapid transit railway and a new mega-shopping area. Contaminated soil and groundwater may interfere with the progress of this project, and residents and shoppers may be exposed to human health risks. The study area has been remediated after application of first remediation technologies. Of the entire area, several sites were still contaminated by waste materials and petroleum. For zinc (Zn) contamination, high Zn concentrations were detected because waste materials were disposed in the entire area. For petroleum contamination, high total petroleum hydrocarbon (TPH) and hydrocarbon degrading microbe concentrations were observed at the depth of 7 m because the underground petroleum storage tank had previously been located at this site. Correlation results suggest that TPH (soil) concentration is still related with TPH (groundwater) concentration. The relationship is taken into account in the Spearman coefficient (α).

A TOXICITY ASSESSMENT APPROACH FOR EVALUATION OF IN-SITU BIOREMEDIATION OF PAH CONTAMINATED SEDIMENTS

EPA Science Inventory

Polycyclic aromatic hydrocarbons (PAHs) represent a group of organic contaminants known for their prevalence and persistence in petroleum-impacted environment such as groundwater, soils and sediments. Many high molecular weight PAHs are suspected carcinogens and the existence of...

Molecular profiling of marine fauna: integration of omics with environmental assessment of the world's oceans.

PubMed

Veldhoen, Nik; Ikonomou, Michael G; Helbing, Caren C

2012-02-01

Many species that contribute to the commercial and ecological richness of our marine ecosystems are harbingers of environmental change. The ability of organisms to rapidly detect and respond to changes in the surrounding environment represents the foundation for application of molecular profiling technologies towards marine sentinel species in an attempt to identify signature profiles that may reside within the transcriptome, proteome, or metabolome and that are indicative of a particular environmental exposure event. The current review highlights recent examples of the biological information obtained for marine sentinel teleosts, mammals, and invertebrates. While in its infancy, such basal information can provide a systems biology framework in the detection and evaluation of environmental chemical contaminant effects on marine fauna. Repeated evaluation across different seasons and local marine environs will lead to discrimination between signature profiles representing normal variation within the complex milieu of environmental factors that trigger biological response in a given sentinel species and permit a greater understanding of normal versus anthropogenic-associated modulation of biological pathways, which prove detrimental to marine fauna. It is anticipated that incorporation of contaminant-specific molecular signatures into current risk assessment paradigms will lead to enhanced wildlife management strategies that minimize the impacts of our industrialized society on marine ecosystems. Copyright © 2011 Elsevier Inc. All rights reserved.

Approaches for assessment of terrestrial vertebrate responses to contaminants: moving beyond individual organisms

USGS Publications Warehouse

Albers, P.H.; Heinz, G.H.; Hall, R.J.; Albers, Peter H.; Heinz, Gary H.; Ohlendorf, Harry M.

2000-01-01

Conclusions: A need for a broader range ofinformation on effects of contaminants on individuals exists among the 4 classes of terrestrial vertebrates, especially mammals, reptiles, and amphibians. Separation of contaminant effects from other effects and reduction of speculative extrapolation within and among species requires information that can be produced only by combined field and laboratory investigations that incorporate seasonal or annual cycles and important spatial and interaction conditions. Assessments of contaminant effects at the population level and higher are frequently dependent on extrapolations from a lower organizational level. Actual measurements of the effects of contaminants on populations or communities, possibly in conjunction with case studies that establish relations between effects on individuals and effects on populations, are needed to reduce the uncertainty associated with these extrapolations. Associated with these assessment levels is the need for acceptable definitions of what we mean when we refer to a 'meaningful population change' or an 'effect on communities or ecosystems.' At these higher levels of organization we are also confronted with the need for procedures useful for separating contaminant effects from effects caused by other environmental conditions. Although the bulk of literature surveyed was of the focused cause-and-effect type that is necessary for proving relations between contaminants and wildlife, community or ecosystem field assessments, as sometimes performed with reptiles and amphibians, might be a useful alternative for estimating the potential of a contaminant to cause environmental harm. Assumptions about the special usefulness of reptiles and amphibians as environmental indicators ought to be tested with comparisons to mammals and birds. Information on the effects of contaminants above the individual level is needed to generate accurate estimates of the potential consequences of anthropogenic pollution (e

A multi-level assessment methodology for determining the potential for groundwater contamination by pesticides.

PubMed

Crowe, A S; Booty, W G

1995-05-01

A multi-level pesticide assessment methodology has been developed to permit regulatory personnel to undertake a variety of assessments on the potential for pesticide used in agricultural areas to contaminate the groundwater regime at an increasingly detailed geographical scale of investigation. A multi-level approach accounts for a variety of assessment objectives and detail required in the assessment, the restrictions on the availability and accuracy of data, the time available to undertake the assessment, and the expertise of the decision maker. The level 1: regional scale is designed to prioritize districts having a potentially high risk for groundwater contamination from the application of a specific pesticide for a particular crop. The level 2: local scale is used to identify critical areas for groundwater contamination, at a soil polygon scale, within a district. A level 3: soil profile scale allows the user to evaluate specific factors influencing pesticide leaching and persistence, and to determine the extent and timing of leaching, through the simulation of the migration of a pesticide within a soil profile. Because of the scale of investigation, limited amount of data required, and qualitative nature of the assessment results, the level 1 and level 2 assessment are designed primarily for quick and broad guidance related to management practices. A level 3 assessment is more complex, requires considerably more data and expertise on the part of the user, and hence is designed to verify the potential for contamination identified during the level 1 or 2 assessment. The system combines environmental modelling, geographical information systems, extensive databases, data management systems, expert systems, and pesticide assessment models, to form an environmental information system for assessing the potential for pesticides to contaminate groundwater.

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.

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.

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

SURROGATE SPECIES IN ASSESSING CONTAMINANT RISK FOR ENDANGERED FISHES

EPA Science Inventory

Rainbow trout, fathead minnows, and sheepshead minnows were tested as surrogate species to assess contaminant risk for 17 endangered fishes and one toad species. Acute toxicity tests were conducted with carbaryl, copper, 4-nonylphenol, pentachlorophenol, and permethrin in accord...

Groundwater and Air Contamination: Risk, Toxicity, Exposure Assessment, Policy, and Regulation

NASA Astrophysics Data System (ADS)

Watts, R. J.; Teel, A. L.

2003-12-01

The improper disposal of hazardous wastes and subsequent contamination of surface and groundwaters has exposed the public and ecosystems to toxic chemicals that have detrimental consequences. The cost of cleaning up the thousands of hazardous waste sites throughout the world is daunting, and the effort to do so is economically impractical. As a result, some level of contamination will always remain, both locally and globally. The presence of a residual level of contamination carries with it the probability of negative impacts on the world's population; e.g., enhanced risk of cancer or the onset of neurological disorders. Risk is the probability of such events. Risk assessments are routinely performed at contaminated sites and in areas of widespread environmental contamination, such as an entire aquifer, as a means of quantifying the potential threats to public health and to ecosystems.

Estimation and assessment of Mars contamination.

PubMed

Debus, A

2005-01-01

respect to all types of contamination. Answering this question, will help to assess the potential effects of such contamination on scientific results and will address concerns relative to any ethical considerations about the contamination of other planets. c2005 COSPAR. Published by Elsevier Ltd. All rights reserved.

Generic Assessment Criteria for human health risk assessment of potentially contaminated land in China.

PubMed

Cheng, Yuanyuan; Nathanail, Paul C

2009-12-20

Generic Assessment Criteria (GAC) are derived using widely applicable assumptions about the characteristics and behaviour of contaminant sources, pathways and receptors. GAC provide nationally consistent guidance, thereby saving money and time. Currently, there are no human health based Generic Assessment Criteria (GAC) for contaminated sites in China. Protection of human health is therefore difficult to ensure and demonstrate; and the lack of GAC makes it difficult to tell if there is potential significant risk to human health unless site-specific criteria are derived. This paper derived Chinese GAC (GAC) for five inorganic and eight organic substances for three regions in China for three land uses: urban residential without plant uptake, Chinese cultivated land, and commercial/industrial using the SNIFFER model. The SNIFFER model has been further implemented with a dermal absorption algorithm and the model default input values have been changed to reflect the Chinese exposure scenarios. It is envisaged that the modified SNIFFER model could be used to derive GAC for more contaminants, more Regions, and more land uses. Further research to enhance the reliability and acceptability of the GAC is needed in regional/national surveys in diet and working patterns.

Assessing Contamination Potential of Nitrate-N in Groundwater of Lanyang Plain

NASA Astrophysics Data System (ADS)

Liang, Ching-Ping; Tu, Yu-Lin; Lin, Chien-Wen; Jang, Cheng-Shin

2013-04-01

Nitrate-N pollution is often relevant to agricultural activities such as the fertilization of crops. Significant increases in the nitrate-N pollution of groundwater are found in natural recharging zones of Taiwan. The increasing nitrate-N contamination seriously threatens public drinking water supply and human health. Constructing a correct map of aquifer contamination potential is an effective and feasible way to protect groundwater for quality assessment and management. Therefore, in this study, we use DRASTIC model with the help of geographic information system (GIS) to assess and predict the contamination potential of nitrate-N in the aquifer of Lanyang Plain, Taiwan. Seven factors of hydrogeology and hydrology, which includes seven parameters - Depth to groundwater, net Recharge, Aquifer media, Soil media, Topography, Impact of vadose zone, and hydraulic Conductivity, are considered to carry out this assessment. The validity of the presented model is established by comparing the results with the measured nitrate concentration in wells within the study area. Adjusting factor weightings via the discriminant analysis is performed to improve the assessment and prediction. The analyzed results can provide residents with suggestive strategies against nitrate-N pollution in agricultural regions and government administrators with explicit information of Nitrate-N pollution extents when plans of water resources are considered.

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.

Surface sediment quality relative to port activities: A contaminant-spectrum assessment.

PubMed

Yu, Shen; Hong, Bing; Ma, Jun; Chen, Yongshan; Xi, Xiuping; Gao, Jingbo; Hu, Xiuqin; Xu, Xiangrong; Sun, Yuxin

2017-10-15

Ports are facing increasing environmental concerns with their importance to the global economy. Numerous studies indicated sediment quality deterioration in ports; however, the deterioration is not discriminated for each port activity. This study investigated a spectrum of contaminants (metals and organic pollutants) in surface sediments at 20 sampling points in Port Ningbo, China, one of the top five world ports by volume. The spectrum of contaminants (metals and organic pollutants) was quantified following marine sediment quality guidelines of China and USA and surface sediment quality was assessed according to thresholds of the two guidelines. Coupling a categorical matrix of port activities with the matrix of sedimentary contaminants revealed that contaminants were highly associated with the port operations. Ship repair posed a severe chemical risk to sediment. Operations of crude oil and coal loadings were two top activities related to organic pollutants in sediments while port operations of ore and container loadings discharged metals. Among the 20 sampling points, Cu, Zn, Pb, and DDT and its metabolites were the priority contaminants influencing sediment quality. Overall, surface sediments in Port Ningbo had relatively low environmental risks but ship repair is an environmental concern that must be addressed. This study provides a practical approach for port activity-related quality assessment of surface sediments in ports that could be applicable in many world sites. Copyright © 2017 Elsevier B.V. All rights reserved.

RAPID ASSESSMENT OF POTENTIAL GROUND-WATER CONTAMINATION UNDER EMERGENCY RESPONSE CONDITIONS

EPA Science Inventory

Emergency response actions at chemical spills and abandoned hazardous waste sites often require rapid assessment of the potential for groundwater contamination by the chemical or waste compound. This manual provides a rapid assessment methodology for performing such an evaluation...

ISSUES IN ASSESSING LOW LEVEL IONIZABLE CONTAMINANT PARTITIONING IN SOILS AND SEDIMENTS

EPA Science Inventory

Solubilization has profound implications for such diverse risk assessment activities as assessing sediment contaminant porewater exposures to benthic fauna, determining half lives of refractory toxicants in natural soils and sediments, and assessing the fate and transport of th...

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...

Assessment of soil contamination--a functional perspective.

PubMed

van Straalen, Nico M

2002-01-01

In many industrialized countries the use of land is impeded by soil pollution from a variety of sources. Decisions on clean-up, management or set-aside of contaminated land are based on various considerations, including human health risks, but ecological arguments do not have a strong position in such assessments. This paper analyses why this should be so, and what ecotoxicology and theoretical ecology can improve on the situation. It seems that soil assessment suffers from a fundamental weakness, which relates to the absence of a commonly accepted framework that may act as a reference. Soil contamination can be assessed both from a functional perspective and a structural perspective. The relationship between structure and function in ecosystems is a fundamental question of ecology which receives a lot of attention in recent literature, however, a general concept that may guide ecotoxicological assessments has not yet arisen. On the experimental side, a good deal of progress has been made in the development and standardized use of terrestrial model ecosystems (TME). In such systems, usually consisting of intact soil columns incubated in the laboratory under conditions allowing plant growth and drainage of water, a compromise is sought between field relevance and experimental manageability. A great variety of measurements can be made on such systems, including microbiological processes and activities, but also activities of the decomposer soil fauna. I propose that these TMEs can be useful instruments in ecological soil quality assessments. In addition a "bioinformatics approach" to the analysis of data obtained in TME experiments is proposed. Soil function should be considered as a multidimensional concept and the various measurements can be considered as indicators, whose combined values define the "normal operating range" of the system. Deviations from the normal operating range indicate that the system is in a condition of stress. It is hoped that more work

Biological Activity Assessment in Mexican Tropical Soils with Different Hydrocarbon Contamination Histories.

PubMed

Riveroll-Larios, Jessica; Escalante-Espinosa, Erika; Fócil-Monterrubio, Reyna L; Díaz-Ramírez, Ildefonso J

The use of soil health indicators linked to microbial activities, such as key enzymes and respirometric profiles, helps assess the natural attenuation potential of soils contaminated with hydrocarbons. In this study, the intrinsic physicochemical characteristics, biological activity and biodegradation potential were recorded for two soils with different contamination histories (>5 years and <1 months). The enzymatic activity (lipase and dehydrogenase) as well as microbiological and mineralisation profiles were measured in contaminated soil samples. Soil suspensions were tested as microbial inocula in biodegradation potential assays using contaminated perlite as an inert support. The basal respiratory rate of the recently contaminated soil was 15-38 mg C-CO 2  kg -1 h -1 , while the weathered soil presented a greater basal mineralisation capacity of 55-70 mg C-CO 2 kg -1 h -1 . The basal levels of lipase and dehydrogenase were significantly greater than those recorded in non-contaminated soils (551 ± 21 μg pNP g -1 ). Regarding the biodegradation potential assessment, the lipase (1000-3000 μg pNP g -1 of perlite) and dehydrogenase (~3000 μg INF g -1 of perlite) activities in the inoculum of the recently contaminated soil were greater than those recorded in the inoculum of the weathered soil. This was correlated with a high mineralisation rate (~30 mg C-CO 2 kg -1 h -1 ) in the recently contaminated soil and a reduction in hydrocarbon concentration (~30 %). The combination of an inert support and enzymatic and respirometric analyses made it possible to detect the different biodegradation capacities of the studied inocula and the natural attenuation potential of a recently contaminated soil at high hydrocarbon concentrations.

Community-based risk assessment of water contamination from high-volume horizontal hydraulic fracturing.

PubMed

Penningroth, Stephen M; Yarrow, Matthew M; Figueroa, Abner X; Bowen, Rebecca J; Delgado, Soraya

2013-01-01

The risk of contaminating surface and groundwater as a result of shale gas extraction using high-volume horizontal hydraulic fracturing (fracking) has not been assessed using conventional risk assessment methodologies. Baseline (pre-fracking) data on relevant water quality indicators, needed for meaningful risk assessment, are largely lacking. To fill this gap, the nonprofit Community Science Institute (CSI) partners with community volunteers who perform regular sampling of more than 50 streams in the Marcellus and Utica Shale regions of upstate New York; samples are analyzed for parameters associated with HVHHF. Similar baseline data on regional groundwater comes from CSI's testing of private drinking water wells. Analytic results for groundwater (with permission) and surface water are made publicly available in an interactive, searchable database. Baseline concentrations of potential contaminants from shale gas operations are found to be low, suggesting that early community-based monitoring is an effective foundation for assessing later contamination due to fracking.

Contamination study

NASA Astrophysics Data System (ADS)

Johnson, R. Barry; Herren, Kenneth A.

1990-09-01

The time dependence of the angular reflectance from molecularly contaminated optical surfaces in the Vacuum Ultraviolet (VUV) is measured. The light scattering measurements are accomplished in situ on optical surfaces in real time during deposition of molecular contaminants. The measurements are taken using non-coherent VUV sources with the predominant wavelengths being the Krypton resonance lines at 1236 and 1600 A. Detection of the scattered light is accomplished using a set of three solar blind VUV photomultipliers. An in-plane VUV BRDF (Bidirectional Reflectance Distribution Functions) experiment is described and details of the ongoing program to characterize optical materials exposed to the space environment is reported.

ASSESSING CONTAMINANT SENSITIVITY OF ENDANGERED AND THREATENED AQUATIC SPECIES WITH ACUTE TOXICITY TESTS

EPA Science Inventory

Assessment of contaminant impacts to endangered and threatened (listed) species requires understanding of a species' sensitivity to particular chemicals. The most direct approach would be to determine the sensitivity of a listed species to a particular contaminant or perturbation...

Optical Characterization of Molecular Contaminant Films

NASA Technical Reports Server (NTRS)

Visentine, James T.

2007-01-01

A semi-empirical method of optical characterization of thin contaminant films on surfaces of optical components has been conceived. The method was originally intended for application to films that become photochemically deposited on such optical components as science windows, lenses, prisms, thinfilm radiators, and glass solar-cell covers aboard spacecraft and satellites in orbit. The method should also be applicable, with suitable modifications, to thin optical films (whether deposited deliberately or formed as contaminants) on optical components used on Earth in the computer microchip laser communications and thin-film industries. The method is expected to satisfy the need for a means of understanding and predicting the reductions in spectral transmittance caused by contaminant films and the consequent deterioration of performances of sensitive optical systems. After further development, this method could become part of the basis of a method of designing optical systems to minimize or compensate for the deleterious effects of contaminant films. In the original outer-space application, these deleterious effects are especially pronounced because after photochemical deposition, the films become darkened by further exposure to solar vacuum ultraviolet (VUV) radiation. In this method, thin contaminant films are theoretically modeled as thin optical films, characterized by known or assumed values of thickness, index of refraction, and absorption coefficient, that form on the outer surfaces of the original antireflection coating on affected optical components. The assumed values are adjusted as needed to make actual spectral transmittance values approximate observed ones as closely as possible and to correlate these values with amounts of VUV radiation to which the optical components have been exposed. In an initial study, the method was applied in correlating measured changes in transmittance of high-purity fused silica photochemically coated with silicone films of

Molecular contamination math model support

NASA Technical Reports Server (NTRS)

Wells, R.

1983-01-01

The operation and features of a preprocessor for the Shuttle/Payload Contamination Evaluation Program Version 2) are described. A preliminary preprocessor for SPACE 2 is developed. Further refinements and enhancements of the preprocessor to insure complete user friendly operation, are recommended.

Methodology for back-contamination risk assessment for a Mars sample return mission

NASA Technical Reports Server (NTRS)

Merkhofer, M. W.; Quinn, D. J.

1977-01-01

The risk of back-contamination from Mars Surface Sample Return (MSSR) missions is assessed. The methodology is designed to provide an assessment of the probability that a given mission design and strategy will result in accidental release of Martian organisms acquired as a result of MSSR. This is accomplished through the construction of risk models describing the mission risk elements and their impact on back-contamination probability. A conceptual framework is presented for using the risk model to evaluate mission design decisions that require a trade-off between science and planetary protection considerations.

Human health implications, risk assessment and remediation of As-contaminated water: A critical review.

PubMed

Shakoor, Muhammad Bilal; Nawaz, Rab; Hussain, Fida; Raza, Maimoona; Ali, Shafaqat; Rizwan, Muhammad; Oh, Sang-Eun; Ahmad, Sajjad

2017-12-01

Arsenic (As) is a naturally occurring metalloid and Class-A human carcinogen. Exposure to As via direct intake of As-contaminated water or ingestion of As-contaminated edible crops is considered a life threatening problem around the globe. Arsenic-laced drinking water has affected the lives of over 200 million people in 105 countries worldwide. Limited data are available on various health risk assessment models/frameworks used to predict carcinogenic and non-carcinogenic health effects caused by As-contaminated water. Therefore, this discussion highlights the need for future research focusing on human health risk assessment of individual As species (both organic and inorganic) present in As-contaminated water. Various conventional and latest technologies for remediation of As-contaminated water are also reviewed along with a discussion of the fate of As-loaded waste and sludge. Copyright © 2017 Elsevier B.V. All rights reserved.

Opportunities and challenges of integrating ecological restoration into assessment and management of contaminated ecosystems.

PubMed

Hull, Ruth N; Luoma, Samuel N; Bayne, Bruce A; Iliff, John; Larkin, Daniel J; Paschke, Mark W; Victor, Sasha L; Ward, Sara E

2016-04-01

Ecosystem restoration planning near the beginning of the site assessment and management process ("early integration") involves consideration of restoration goals from the outset in developing solutions for contaminated ecosystems. There are limitations to integration that stem from institutional barriers, few successful precedents, and limited availability of guidance. Challenges occur in integrating expertise from various disciplines and multiple, sometimes divergent interests and goals. The more complex process can result in timing, capacity, communication, and collaboration challenges. On the other hand, integrating the 2 approaches presents new and creative opportunities. For example, integration allows early planning for expanding ecosystem services on or near contaminated lands or waters that might otherwise have been unaddressed by remediation alone. Integrated plans can explicitly pursue ecosystem services that have market value, which can add to funds for long-term monitoring and management. Early integration presents opportunities for improved and productive collaboration and coordination between ecosystem restoration and contaminant assessment and management. Examples exist where early integration facilitates liability resolution and generates positive public relations. Restoration planning and implementation before the completion of the contaminated site assessment, remediation, or management process ("early restoration") can facilitate coordination with offsite restoration options and a regional approach to restoration of contaminated environments. Integration of performance monitoring, for both remedial and restoration actions, can save resources and expand the interpretive power of results. Early integration may aid experimentation, which may be more feasible on contaminated lands than in many other situations. The potential application of concepts and tools from adaptive management is discussed as a way of avoiding pitfalls and achieving benefits in

Incorporating ecologically relevant habitat and demographic data in assessment of contaminant risk to wildlife

EPA Science Inventory

Evaluating population-level effects of contamination on wildlife requires specific information on habitat quality, species distribution, and contaminant concentration. Establishing broadly applicable thresholds for risk assessment involves an understanding of the applicability o...

Macroscopic and molecular-scale assessment of soil lead contamination impacted by seasonal dove hunting activities

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

Arai, Y.; Tappero, R.; Rick, A.R.

Environmental contamination of lead (Pb) in soils and sediments poses serious threats to human and ecological health. The objective of this study is to investigate the effect of seasonal dove sports hunting activities on Pb contamination in acid forest soils. A grid sampling method was used to investigate the spatial distribution of Pb contamination in surface soils. Soils were analyzed for total metal(loid) concentration and characterized for physicochemical properties and mineralogy. Adsorption isotherm experiments were also conducted to understand the reactivity and retention capacity of Pb(II) in soils. Finally, synchrotron-based X-ray microprobe and X-ray absorption spectroscopy were used to understandmore » the chemical speciation of Pb that controls the retention/release mechanisms of Pb in soils. There was no excessive accumulation of Pb at the site. However, the concentration of Pb in surface soils was greater than the background level (<16 mg kg{sup -1}). The contamination level of Pb was as high as 67 mg kg{sup -1} near a patch of corn field where lime was frequently applied. A microfocused X-ray microprobe analysis showed the presence of Pb pellet fragments that predominantly contain oxidized Pb(II), suggesting that oxidative dissolution was occurring in soils. Dissolved Pb(II) can be readily retained in soils up to {approx}3,600 mg kg{sup -1} via inner-sphere and outer-sphere surface complexation on carbon and aluminol functional groups of soil components, suggesting that partitioning reactions control the concentration of Pb in soil solution. The fate of Pb is likely to be controlled by (1) oxidative dissolution process of Pb(0) pellets and (2) the release of outer-sphere and/or inner-sphere Pb surface complexes in humic substances and aluminosilicate/Al oxyhydroxides. Although no remedial actions are immediately required, the long-term accumulation of Pb in soils should be carefully monitored in protecting ecosystem and water quality at the dove

Food-chain contamination evaluations in ecological risk assessments

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

Linder, G.

Food-chain models have become increasingly important within the ecological risk assessment process. This is the case particularly when acute effects are not readily apparent, or the contaminants of concern are not readily detoxified, have a high likelihood for partitioning into lipids, or have specific target organs or tissues that may increase their significance in evaluating their potential adverse effects. An overview of food-chain models -- conceptual, theoretical, and empirical -- will be considered through a series of papers that will focus on their application within the ecological risk assessment process. Whether a food-chain evaluation is being developed to address relativelymore » simple questions related to chronic effects of toxicants on target populations, or whether a more complex food-web model is being developed to address questions related to multiple-trophic level transfers of toxicants, the elements within the food chain contamination evaluation can be generalized to address the mechanisms of toxicant accumulation in individual organisms. This can then be incorporated into more elaborate models that consider these organismal-level processes within the context of a species life-history or community-level responses that may be associated with long-term exposures.« less

A Bayesian belief network approach for assessing uncertainty in conceptual site models at contaminated sites

NASA Astrophysics Data System (ADS)

Thomsen, Nanna I.; Binning, Philip J.; McKnight, Ursula S.; Tuxen, Nina; Bjerg, Poul L.; Troldborg, Mads

2016-05-01

A key component in risk assessment of contaminated sites is in the formulation of a conceptual site model (CSM). A CSM is a simplified representation of reality and forms the basis for the mathematical modeling of contaminant fate and transport at the site. The CSM should therefore identify the most important site-specific features and processes that may affect the contaminant transport behavior at the site. However, the development of a CSM will always be associated with uncertainties due to limited data and lack of understanding of the site conditions. CSM uncertainty is often found to be a major source of model error and it should therefore be accounted for when evaluating uncertainties in risk assessments. We present a Bayesian belief network (BBN) approach for constructing CSMs and assessing their uncertainty at contaminated sites. BBNs are graphical probabilistic models that are effective for integrating quantitative and qualitative information, and thus can strengthen decisions when empirical data are lacking. The proposed BBN approach facilitates a systematic construction of multiple CSMs, and then determines the belief in each CSM using a variety of data types and/or expert opinion at different knowledge levels. The developed BBNs combine data from desktop studies and initial site investigations with expert opinion to assess which of the CSMs are more likely to reflect the actual site conditions. The method is demonstrated on a Danish field site, contaminated with chlorinated ethenes. Four different CSMs are developed by combining two contaminant source zone interpretations (presence or absence of a separate phase contamination) and two geological interpretations (fractured or unfractured clay till). The beliefs in each of the CSMs are assessed sequentially based on data from three investigation stages (a screening investigation, a more detailed investigation, and an expert consultation) to demonstrate that the belief can be updated as more information

Contamination Control Assessment of the World's Largest Space Environment Simulation Chamber

NASA Technical Reports Server (NTRS)

Snyder, Aaron; Henry, Michael W.; Grisnik, Stanley P.; Sinclair, Stephen M.

2012-01-01

The Space Power Facility s thermal vacuum test chamber is the largest chamber in the world capable of providing an environment for space simulation. To improve performance and meet stringent requirements of a wide customer base, significant modifications were made to the vacuum chamber. These include major changes to the vacuum system and numerous enhancements to the chamber s unique polar crane, with a goal of providing high cleanliness levels. The significance of these changes and modifications are discussed in this paper. In addition, the composition and arrangement of the pumping system and its impact on molecular back-streaming are discussed in detail. Molecular contamination measurements obtained with a TQCM and witness wafers during two recent integrated system tests of the chamber are presented and discussed. Finally, a concluding remarks section is presented.

ASSESSMENT OF STACHYBOTRYS REGROWTH ON CONTAMINATED WALLBOARD AFTER TREATMENT WITH COMMON SURFACE CLEANERS/DISINFECTANTS

EPA Science Inventory

The paper describes results of experiments assessing the efficacy of treating mold-contaminated gypsum wallboard with cleaners and/or disinfectants. Although the accepted recommendations for handling Stachybotrys chartarum contaminated gypsum wallboard are removal and replacement...

ELEMENTAL FISH TISSUE CONTAMINATION IN NORTHEASTERN U.S. LAKES: EVALUATION OF AN APPROACH TO REGIONAL ASSESSMENT

EPA Science Inventory

The approach of the Environmental Monitoring and Assessment Program (EMAP) to monitoring of fish tissue contaminants is shown to have utility for regional assessment, and for discrimination of regional from local contamination. The survey sampling design employed EMAP can be used...

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

Indices of soil contamination by heavy metals - methodology of calculation for pollution assessment (minireview).

PubMed

Weissmannová, Helena Doležalová; Pavlovský, Jiří

2017-11-07

This article provides the assessment of heavy metal soil pollution with using the calculation of various pollution indices and contains also summarization of the sources of heavy metal soil pollution. Twenty described indices of the assessment of soil pollution consist of two groups: single indices and total complex indices of pollution or contamination with relevant classes of pollution. This minireview provides also the classification of pollution indices in terms of the complex assessment of soil quality. In addition, based on the comparison of metal concentrations in soil-selected sites of the world and used indices of pollution or contamination in soils, the concentration of heavy metal in contaminated soils varied widely, and pollution indices confirmed the significant contribution of soil pollution from anthropogenic activities mainly in urban and industrial areas.

Assessment of arsenic surface contamination in a museum anthropology department.

PubMed

Gribovich, Andrey; Lacey, Steven; Franke, John; Hinkamp, David

2013-02-01

To assess potential arsenic (As) contamination of work surfaces to improve upon the control strategy at an anthropology department in a large natural history museum. Work practices were observed and control strategy reviewed to inform an occupational hygiene assessment strategy utilizing surface wipe sampling. A total of 35 sampling targets were identified, focusing on surfaces that receive high touch traffic, including workstations, artifact transport carts, and elevator buttons. Arsenic sampling and analysis were performed using reference method Occupational Safety and Health Administration ID-125G. Four of the sampling areas returned detectable levels of As, ranging from 0.052 to 0.350 μg/100 cm. Workplace observations and wipe sampling data enabled the development of recommendations to help to further reduce potential occupational exposure to As. Continuous reduction of surface contamination is prudent for known human carcinogens.

ELEMENTAL FISH TISSUE CONTAMINATION IN NORTHEASTERN U.S. LAKES: EVALUATION OF AN APPROACH TO REGIONAL ASSESSMENT

EPA Science Inventory

The approach of the Environmental Monitoring and Assessment Program (EMAP) to monitoring of fish tissue contaminants is shown to have utility for regional assessment,and for discrimination of regional from local contamination.The survey sampling design employed by EMAP can be use...

SUDOQU, a new dose-assessment methodology for radiological surface contamination.

PubMed

van Dillen, Teun; van Dijk, Arjan

2018-06-12

A new methodology has been developed for the assessment of the annual effective dose resulting from removable and fixed radiological surface contamination. It is entitled SUDOQU (SUrface DOse QUantification) and it can for instance be used to derive criteria for surface contamination related to the import of non-food consumer goods, containers and conveyances, e.g., limiting values and operational screening levels. SUDOQU imposes mass (activity)-balance equations based on radioactive decay, removal and deposition processes in indoor and outdoor environments. This leads to time-dependent contamination levels that may be of particular importance in exposure scenarios dealing with one or a few contaminated items only (usually public exposure scenarios, therefore referred to as the 'consumer' model). Exposure scenarios with a continuous flow of freshly contaminated goods also fall within the scope of the methodology (typically occupational exposure scenarios, thus referred to as the 'worker model'). In this paper we describe SUDOQU, its applications, and its current limitations. First, we delineate the contamination issue, present the assumptions and explain the concepts. We describe the relevant removal, transfer, and deposition processes, and derive equations for the time evolution of the radiological surface-, air- and skin-contamination levels. These are then input for the subsequent evaluation of the annual effective dose with possible contributions from external gamma radiation, inhalation, secondary ingestion (indirect, from hand to mouth), skin contamination, direct ingestion and skin-contact exposure. The limiting effective surface dose is introduced for issues involving the conservatism of dose calculations. SUDOQU can be used by radiation-protection scientists/experts and policy makers in the field of e.g. emergency preparedness, trade and transport, exemption and clearance, waste management, and nuclear facilities. Several practical examples are

Selection of plants for phytoremediation of soils contaminated with radionuclides

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

Entry J.A.; Vance, N.C.; Watrud, L.S.

1996-12-31

Remediation of soil contaminated with radionuclides typically requires that soil be removed from the site and treated with various dispersing and chelating chemicals. Numerous studies have shown that radionuclides are generally not leached from the top 0.4 meters of soil, where plant roots actively accumulate elements. Restoration of large areas of land contaminated with low levels of radionuclides may be feasible using phytoremediation. Criteria for the selection of plants for phytoremediation, molecular approaches to increase radio nuclide uptake, effects of cultural practices on uptake and assessment of environmental effects of phytoremediation will be discussed.

Culture and molecular identification of fungal contaminants in edible bird nests.

PubMed

Chen, Jennifer Xiao Jing; Wong, Shew Fung; Lim, Patricia Kim Chooi; Mak, Joon Wah

2015-01-01

Widespread food poisoning due to microbial contamination has been a major concern for the food industry, consumers and governing authorities. This study is designed to determine the levels of fungal contamination in edible bird nests (EBNs) using culture and molecular techniques. Raw EBNs were collected from five house farms, and commercial EBNs were purchased from five Chinese traditional medicine shops (companies A-E) in Peninsular Malaysia. The fungal contents in the raw and commercial EBNs, and boiled and unboiled EBNs were determined. Culturable fungi were isolated and identified. In this study, the use of these methods revealed that all EBNs had fungal colony-forming units (CFUs) that exceeded the limit set by Standards and Industrial Research Institute of Malaysia (SIRIM) for yeast and moulds in EBNs. There was a significant difference (p < 0.05) in the number of types of fungi isolated from raw and commercial EBNs, but no significant difference in the reduction of the number of types of fungi after boiling the EBNs (p > 0.05). The types of fungi isolated from the unboiled raw EBNs were mainly soil, plant and environmental fungi, while the types of fungi isolated from the boiled raw EBNs, unboiled and boiled commercial EBNs were mainly environmental fungi. Aspergillus sp., Candida sp., Cladosporium sp., Neurospora sp. and Penicillum sp. were the most common fungi isolated from the unboiled and boiled raw and commercial EBNs. Some of these fungi are mycotoxin producers and cause opportunistic infections in humans. Further studies to determine the mycotoxin levels and methods to prevent or remove these contaminations from EBNs for safe consumption are necessary. The establishment and implementation of stringent regulations for the standards of EBNs should be regularly updated and monitored to improve the quality of the EBNs and consumer safety.

Use of life cycle assessments to evaluate the environmental footprint of contaminated sediment remediation.

PubMed

Sparrevik, Magnus; Saloranta, Tuomo; Cornelissen, Gerard; Eek, Espen; Fet, Annik Magerholm; Breedveld, Gijs D; Linkov, Igor

2011-05-15

Ecological and human risks often drive the selection of remedial alternatives for contaminated sediments. Traditional human and ecological risk assessment (HERA) includes assessing risk for benthic organisms and aquatic fauna associated with exposure to contaminated sediments before and after remediation as well as risk for human exposure but does not consider the environmental footprint associated with implementing remedial alternatives. Assessment of environmental effects over the whole life cycle (i.e., Life Cycle Assessment, LCA) could complement HERA and help in selecting the most appropriate sediment management alternative. Even though LCA has been developed and applied in multiple environmental management cases, applications to contaminated sediments and marine ecosystems are in general less frequent. This paper implements LCA methodology for the case of the polychlorinated dibenzo-p-dioxins and -furans (PCDD/F)-contaminated Grenland fjord in Norway. LCA was applied to investigate the environmental footprint of different active and passive thin-layer capping alternatives as compared to natural recovery. The results showed that capping was preferable to natural recovery when analysis is limited to effects related to the site contamination. Incorporation of impacts related to the use of resources and energy during the implementation of a thin layer cap increase the environmental footprint by over 1 order of magnitude, making capping inferior to the natural recovery alternative. Use of biomass-derived activated carbon, where carbon dioxide is sequestered during the production process, reduces the overall environmental impact to that of natural recovery. The results from this study show that LCA may be a valuable tool for assessing the environmental footprint of sediment remediation projects and for sustainable sediment management.

The molecular biology capstone assessment: a concept assessment for upper-division molecular biology students.

PubMed

Couch, Brian A; Wood, William B; Knight, Jennifer K

2015-03-02

Measuring students' conceptual understandings has become increasingly important to biology faculty members involved in evaluating and improving departmental programs. We developed the Molecular Biology Capstone Assessment (MBCA) to gauge comprehension of fundamental concepts in molecular and cell biology and the ability to apply these concepts in novel scenarios. Targeted at graduating students, the MBCA consists of 18 multiple-true/false (T/F) questions. Each question consists of a narrative stem followed by four T/F statements, which allows a more detailed assessment of student understanding than the traditional multiple-choice format. Questions were iteratively developed with extensive faculty and student feedback, including validation through faculty reviews and response validation through student interviews. The final assessment was taken online by 504 students in upper-division courses at seven institutions. Data from this administration indicate that the MBCA has acceptable levels of internal reliability (α=0.80) and test-retest stability (r=0.93). Students achieved a wide range of scores with a 67% overall average. Performance results suggest that students have an incomplete understanding of many molecular biology concepts and continue to hold incorrect conceptions previously documented among introductory-level students. By pinpointing areas of conceptual difficulty, the MBCA can provide faculty members with guidance for improving undergraduate biology programs. © 2015 B. A. Couch et al. CBE—Life Sciences Education © 2015 The American Society for Cell Biology. This article is distributed by The American Society for Cell Biology under license from the author(s). It is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

Incorporating biologically based models into assessments of risk from chemical contaminants

NASA Technical Reports Server (NTRS)

Bull, R. J.; Conolly, R. B.; De Marini, D. M.; MacPhail, R. C.; Ohanian, E. V.; Swenberg, J. A.

1993-01-01

The general approach to assessment of risk from chemical contaminants in drinking water involves three steps: hazard identification, exposure assessment, and dose-response assessment. Traditionally, the risks to humans associated with different levels of a chemical have been derived from the toxic responses observed in animals. It is becoming increasingly clear, however, that further information is needed if risks to humans are to be assessed accurately. Biologically based models help clarify the dose-response relationship and reduce uncertainty.

Payload/orbiter contamination control assessment support

NASA Technical Reports Server (NTRS)

Rantanen, R. O.; Ress, E. B.

1975-01-01

The development and use is described of a basic contamination mathematical model of the shuttle orbiter which incorporates specific shuttle orbiter configurations and contamination sources. These configurations and sources were evaluated with respect to known shuttle orbiter operational surface characteristics and specific lines-of-sight which encompass the majority of viewing requirements for shuttle payloads. The results of these evaluations are presented as summary tables for each major source. In addition, contamination minimization studies were conducted and recommendations are made, where applicable, to support the shuttle orbiter design and operational planning for those sources which were identified to present a significant contamination threat.

Soft X-ray-assisted detection method for airborne molecular contaminations (AMCs)

NASA Astrophysics Data System (ADS)

Kim, Changhyuk; Zuo, Zhili; Finger, Hartmut; Haep, Stefan; Asbach, Christof; Fissan, Heinz; Pui, David Y. H.

2015-03-01

Airborne molecular contaminations (AMCs) represent a wide range of gaseous contaminants in cleanrooms. Due to the unintentional nanoparticle or haze formation as well as doping caused by AMCs, improved monitoring and controlling methods for AMCs are urgent in the semiconductor industry. However, measuring ultra-low concentrations of AMCs in cleanrooms is difficult, especially, behind a gas filter. In this study, a novel detection method for AMCs, which is on-line, economical, and applicable for diverse AMCs, was developed by employing gas-to-particle conversion with soft X-ray, and then measuring the generated nanoparticles. Feasibility study of this method was conducted through the evaluations of granular-activated carbons (GACs), which are widely used AMC filter media. Sulfur dioxide (SO2) was used as an AMC for the feasibility study. Using this method, the ultra-low concentrations of SO2 behind GACs were determined in terms of concentrations of generated sulfuric acid (H2SO4) nanoparticles. By calculating SO2 concentrations from the nanoparticle concentrations using empirical correlation equations between them, remarkable sensitivity of this method to SO2 was shown, down to parts-per-trillions, which are too low to detect using commercial gas sensors. Also, the calculated SO2 concentrations showed good agreement with those measured simultaneously by a commercial SO2 monitor at parts-per-billions.

Risk assessment for furan contamination through the food chain in Belgian children.

PubMed

Scholl, Georges; Huybrechts, Inge; Humblet, Marie-France; Scippo, Marie-Louise; De Pauw, Edwin; Eppe, Gauthier; Saegerman, Claude

2012-08-01

Young, old, pregnant and immuno-compromised persons are of great concern for risk assessors as they represent the sub-populations most at risk. The present paper focuses on risk assessment linked to furan exposure in children. Only the Belgian population was considered because individual contamination and consumption data that are required for accurate risk assessment were available for Belgian children only. Two risk assessment approaches, the so-called deterministic and probabilistic, were applied and the results were compared for the estimation of daily intake. A significant difference between the average Estimated Daily Intake (EDI) was underlined between the deterministic (419 ng kg⁻¹ body weight (bw) day⁻¹) and the probabilistic (583 ng kg⁻¹ bw day⁻¹) approaches, which results from the mathematical treatment of the null consumption and contamination data. The risk was characterised by two ways: (1) the classical approach by comparison of the EDI to a reference dose (RfD(chronic-oral)) and (2) the most recent approach, namely the Margin of Exposure (MoE) approach. Both reached similar conclusions: the risk level is not of a major concern, but is neither negligible. In the first approach, only 2.7 or 6.6% (respectively in the deterministic and in the probabilistic way) of the studied population presented an EDI above the RfD(chronic-oral). In the second approach, the percentage of children displaying a MoE above 10,000 and below 100 is 3-0% and 20-0.01% in the deterministic and probabilistic modes, respectively. In addition, children were compared to adults and significant differences between the contamination patterns were highlighted. While major contamination was linked to coffee consumption in adults (55%), no item predominantly contributed to the contamination in children. The most important were soups (19%), dairy products (17%), pasta and rice (11%), fruit and potatoes (9% each).

Assessing Inhalation Exposures Associated with Contamination Events in Water Distribution Systems

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

Davis, Michael J.; Janke, Robert; Taxon, Thomas N.

When a water distribution system (WDS) is contaminated, short-term inhalation exposures to airborne contaminants could occur as the result of domestic water use. The most important domestic sources of such exposures are likely to be showering and the use of aerosol-producing humidifiers, i.e., ultrasonic and impeller (cool-mist) units. A framework is presented for assessing the potential effects of short-term, system-wide inhalation exposures that could result from such activities during a contamination event. This framework utilizes available statistical models for showering frequency and duration, available exposure models for showering and humidifier use, and experimental results on both aerosol generation and themore » volatilization of chemicals during showering. New models for the times when showering occurs are developed using time-use data for the United States. Given a lack of similar models for how humidifiers are used, or the information needed to develop them, an analysis of the sensitivity of results to assumptions concerning humidifier use is presented. The framework is applied using network models for three actual WDSs. Simple models are developed for estimating upper bounds on the potential effects of system-wide inhalation exposures associated with showering and humidifier use. From a system-wide, population perspective, showering could result in significant inhalation doses of volatile chemical contaminants, and humidifier use could result in significant inhalation doses of microbial contaminants during a contamination event. From a system-wide perspective, showering is unlikely to be associated with significant doses of microbial contaminants. In conclusion, given the potential importance of humidifiers as a source of airborne contaminants during a contamination event, an improved understanding of the nature of humidifier use is warranted.« less

Assessing Inhalation Exposures Associated with Contamination Events in Water Distribution Systems

DOE PAGES

Davis, Michael J.; Janke, Robert; Taxon, Thomas N.

2016-12-08

When a water distribution system (WDS) is contaminated, short-term inhalation exposures to airborne contaminants could occur as the result of domestic water use. The most important domestic sources of such exposures are likely to be showering and the use of aerosol-producing humidifiers, i.e., ultrasonic and impeller (cool-mist) units. A framework is presented for assessing the potential effects of short-term, system-wide inhalation exposures that could result from such activities during a contamination event. This framework utilizes available statistical models for showering frequency and duration, available exposure models for showering and humidifier use, and experimental results on both aerosol generation and themore » volatilization of chemicals during showering. New models for the times when showering occurs are developed using time-use data for the United States. Given a lack of similar models for how humidifiers are used, or the information needed to develop them, an analysis of the sensitivity of results to assumptions concerning humidifier use is presented. The framework is applied using network models for three actual WDSs. Simple models are developed for estimating upper bounds on the potential effects of system-wide inhalation exposures associated with showering and humidifier use. From a system-wide, population perspective, showering could result in significant inhalation doses of volatile chemical contaminants, and humidifier use could result in significant inhalation doses of microbial contaminants during a contamination event. From a system-wide perspective, showering is unlikely to be associated with significant doses of microbial contaminants. In conclusion, given the potential importance of humidifiers as a source of airborne contaminants during a contamination event, an improved understanding of the nature of humidifier use is warranted.« less

Assessing Inhalation Exposures Associated with Contamination Events in Water Distribution Systems

PubMed Central

Davis, Michael J.; Janke, Robert; Taxon, Thomas N.

2016-01-01

When a water distribution system (WDS) is contaminated, short-term inhalation exposures to airborne contaminants could occur as the result of domestic water use. The most important domestic sources of such exposures are likely to be showering and the use of aerosol-producing humidifiers, i.e., ultrasonic and impeller (cool-mist) units. A framework is presented for assessing the potential effects of short-term, system-wide inhalation exposures that could result from such activities during a contamination event. This framework utilizes available statistical models for showering frequency and duration, available exposure models for showering and humidifier use, and experimental results on both aerosol generation and the volatilization of chemicals during showering. New models for the times when showering occurs are developed using time-use data for the United States. Given a lack of similar models for how humidifiers are used, or the information needed to develop them, an analysis of the sensitivity of results to assumptions concerning humidifier use is presented. The framework is applied using network models for three actual WDSs. Simple models are developed for estimating upper bounds on the potential effects of system-wide inhalation exposures associated with showering and humidifier use. From a system-wide, population perspective, showering could result in significant inhalation doses of volatile chemical contaminants, and humidifier use could result in significant inhalation doses of microbial contaminants during a contamination event. From a system-wide perspective, showering is unlikely to be associated with significant doses of microbial contaminants. Given the potential importance of humidifiers as a source of airborne contaminants during a contamination event, an improved understanding of the nature of humidifier use is warranted. PMID:27930709

ASSESSING THE ALLERGIC POTENTIAL OF INDOOR AIR FUNGAL CONTAMINANTS

EPA Science Inventory

Assessing the Allergic Potential of Indoor Air Fungal Contaminants
Marsha D W Ward1, Michael E Viana2, Yonjoo Chung3, Najwa Haykal-Coates1, Lisa B Copeland1, Steven H Gavett1, and MaryJane K Selgrade1. 1US EPA, ORD, NHEERL, RTP, NC, USA. 2NCSU, CVM, Raleigh, NC, USA, 3 UNC, S...

A Diagnostic Assessment for Introductory Molecular and Cell Biology

ERIC Educational Resources Information Center

Shi, Jia; Wood, William B.; Martin, Jennifer M.; Guild, Nancy A.; Vicens, Quentin; Knight, Jennifer K.

2010-01-01

We have developed and validated a tool for assessing understanding of a selection of fundamental concepts and basic knowledge in undergraduate introductory molecular and cell biology, focusing on areas in which students often have misconceptions. This multiple-choice Introductory Molecular and Cell Biology Assessment (IMCA) instrument is designed…

USING GENOMICS AND PROTEOMICS TO DIAGNOSE EXPOSURE OF AQUATIC ORGANISMS TO ENVIRONMENTAL CONTAMINANTS

EPA Science Inventory

Advances in molecular biology allow the use of cutting-edge genomic and proteomic tools to assess the effects of environmental contaminants on aquatic organisms. Techniques are available to measure changes in expression of single genes (quantitative real-time PCR) or to measure g...

Long-term assessment of contaminated articles from the Chernobyl reactor.

PubMed

Alkhomashi, N; Monged, M H E

2015-06-01

The Chernobyl accident caused a release of radioactive materials from the reactor into the environment. This event contaminated people, their surroundings and their personal property, especially in the zone around the reactor. Among the affected individuals were British students who were studying in Minsk and Kiev at the time of the Chernobyl accident. These students were exposed to external and internal radiation, and the individuals' articles of clothing were contaminated. The primary objective of this study was to analyze a sample of this contaminated clothing 20 years after the accident using three different detectors, namely, a BP4/4C scintillation detector, a Min-Con Geiger-Müller tube detector and a high-purity germanium (HPGe) detector. The clothing articles were initially assessed and found not to be significantly contaminated. However, there were several hot spots of contamination in various regions of the articles. The net count rates for these hot spots were in the range of 10.00 ± 3.16 c/s to 41.00 ± 6.40 c/s when the BP4/4C scintillation detector was used. The HPGe detector was used to identify the radionuclides present in the clothing, and the results indicated that the only active radionuclide was (137)Cs because of this isotope's long half-life. Copyright © 2015 Elsevier Ltd. All rights reserved.

International Space Station External Contamination Status

NASA Technical Reports Server (NTRS)

Mikatarian, Ron; Soares, Carlos

2000-01-01

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

Contaminants in milk and impact of heating: an assessment study.

PubMed

Awasthi, Vandana; Bahman, Sanjivan; Thakur, Lalit K; Singh, Santosh Kumar; Dua, Ajit; Ganguly, Sanjeev

2012-01-01

The major contaminants usually encountered in milk and milk products include pesticide residues, heavy metals, and aflatoxin M1 (AFM1). Primarily, milk get contaminated before milching, from the cattle feed, from sources/materials used during the processing of milk as well as improper handling of the milk during the pre- and postprocessing period. The purpose of this study was to evaluate the effect of household practices on milk contaminants. Samples of pasteurized as well as unpasteurized milk (Vendor's milk) were analyzed for AFM1, pesticide residues, and heavy metals. Simulating the household practices, the impact of boiling on these contaminants was assessed. The contaminant Aflatoxin M1 (AFM1) was detected at a concentration ranging from 0.071-0.075 ppb in unpasteurized as well as pasteurized milk samples analyzed during the course of study. Moreover, boiling had no impact on the quantity of AFM1 present in the milk. Pesticides and heavy metal contents were found to be within acceptable limits in all the milk samples tested. Mycotoxins especially aflatoxins in cattle feed and their consequential presence in milk and milk products is a serious concern world over as they are reported carcinogens. These fungal toxins are resistant to high temperatures and may lead to various health hazards. Preventive steps must be taken at each stage to ensure good quality of milk and milk products free from these contaminants. Awareness programs and education for the dairy farmers and milk processors may be helpful in this regard.

Ecological risk assessment in legislation on contaminated soil in The Netherlands.

PubMed

Boekhold, Alexandra E

2008-12-01

Recently the Dutch soil policy was revised including new rules for the relocation of contaminated soil and dredged soil material. With these rules, new methods for ecotoxicological risk assessment were implemented. One of the new methods is the assessment of the local toxic pressure of mixtures, also known as the ms-PAF- method, based on the Species Sensitivity Distribution concept. The ms-PAF method is applied for risk assessment of spreading of dredged soil material on adjacent land. Its application will possibly be extended to the derivation of local soil quality standards relevant in the context of soil relocation. The application of the local toxic pressure will probably increase the reuse of contaminated soil and dredged soil material and hence will reduce the amounts considered to be unfit for use. With this method, local ecological risk limits are derived using pore water concentrations and effects on water organisms. Pore water concentrations are subsequently transferred to total soil concentrations using empirical relationships. The methodology does not impose upper limits for total soil concentrations. In soils with a high sorption capacity, total soil concentrations that are considered to be acceptable may be several times higher than the current Dutch intervention values. The possible introduction of the ms-PAF method will open the door to local soil relocation with soils containing large amounts of (semi-permanently soil bound) contaminants. Since the ms-PAF method is not yet properly validated, the lack of evidence of ecological effects using models like the ms-PAF method cannot be regarded as an indication for the absence of effects in reality. The Dutch soil quality decree would gain environmental ambition when the ms-PAF method was combined with a realistic upper limit on total soil concentrations. This would prevent contamination of land by means of soil relocation.

Comparing different methods for assessing contaminant bioavailability during sediment remediation.

PubMed

Jia, Fang; Liao, Chunyang; Xue, Jiaying; Taylor, Allison; Gan, Jay

2016-12-15

Sediment contamination by persistent organic pollutants from historical episodes is widespread and remediation is often needed to clean up severely contaminated sites. Measuring contaminant bioavailability in a before-and-after manner lends to improved assessment of remediation effectiveness. However, a number of bioavailability measurement methods have been developed, posing a challenge in method selection for practitioners. In this study, three different bioavailability measurement methods, i.e., solid phase microextraction (SPME), Tenax desorption, and isotope dilution method (IDM), were compared in evaluating changes in bioavailability of DDT and its degradates in sediment following simulated remediation treatments. When compared to the unamended sediments, all three methods predicted essentially the same degrees of changes in bioavailability after amendment with activated carbon, charcoal or sand. After normalizing over the unamended control, measurements by different methods were linearly correlated with each other, with slopes close to 1. The same observation was further made with a Superfund site marine sediment. This finding suggests that different methods may be used in evaluating remediation efficiency. However, Tenax desorption or IDM consistently offered better sensitivity than SPME in detecting bioavailability changes. Results from this study highlight the value of considering bioavailability when evaluating remediation effectiveness and provide guidance on the selection of bioavailability measurement methods in such assessments. Copyright © 2016 Elsevier B.V. All rights reserved.

PBT assessment and prioritization of contaminants of emerging concern: Pharmaceuticals.

PubMed

Sangion, Alessandro; Gramatica, Paola

2016-05-01

The strong and widespread use of pharmaceuticals, together with incorrect disposal procedures, has recently made these products contaminants of emerging concern (CEC). Unfortunately, little is known about pharmaceuticals' environmental behaviour and ecotoxicity, so that EMEA (European Medicines Agency) released guidelines for the pharmaceuticals' environmental risk assessment. In particular, there is a severe lack of information about persistence, bioaccumulation and toxicity (PBT) of the majority of the thousands of substances on the market. Computational tools, like QSAR (Quantitative Structure Activity Relationship) models, are the only way to screen large sets of chemicals in short time, with the aim of ranking, highlighting and prioritizing the most environmentally hazardous for focusing further experimental studies. In this work we propose a screening method to assess the potential persistence, bioaccumulation and toxicity of more than 1200 pharmaceutical ingredients, based on the application of two different QSAR models. We applied the Insubria-PBT Index, a MLR (Multiple Linear Regression) QSAR model based on four simple molecular descriptors, implemented in QSARINS software, and able to synthesize the PBT potential in a unique cumulative value and the US-EPA PBT Profiler that assesses the PBT behaviour evaluating separately P, B and T. Particular attention was given to the study of Applicability Domain in order to provide reliable predictions. An agreement of 86% was found between the two models and a priority list of 35 pharmaceuticals, highlighted as potential PBTs by consensus, was proposed for further experimental validation. Moreover, the results of this computational screening are in agreement with preliminary experimental data in the literature. This study shows how in silico models can be applied in the hazard assessment to perform preliminary screening and prioritization of chemicals, and how the identification of the structural features, mainly

The first microbiological contamination assessment by deep-sea drilling and coring by the D/V Chikyu at the Iheya North hydrothermal field in the Mid-Okinawa Trough (IODP Expedition 331)

PubMed Central

Yanagawa, Katsunori; Nunoura, Takuro; McAllister, Sean M.; Hirai, Miho; Breuker, Anja; Brandt, Leah; House, Christopher H.; Moyer, Craig L.; Birrien, Jean-Louis; Aoike, Kan; Sunamura, Michinari; Urabe, Tetsuro; Mottl, Michael J.; Takai, Ken

2013-01-01

During the Integrated Ocean Drilling Program (IODP) Expedition 331 at the Iheya North hydrothermal system in the Mid-Okinawa Trough by the D/V Chikyu, we conducted microbiological contamination tests of the drilling and coring operations. The contamination from the drilling mud fluids was assessed using both perfluorocarbon tracers (PFT) and fluorescent microsphere beads. PFT infiltration was detected from the periphery of almost all whole round cores (WRCs). By contrast, fluorescent microspheres were not detected in hydrothermally active core samples, possibly due to thermal decomposition of the microspheres under high-temperature conditions. Microbial contamination from drilling mud fluids to the core interior subsamples was further characterized by molecular-based evaluation. The microbial 16S rRNA gene phylotype compositions in the drilling mud fluids were mainly composed of sequences of Beta- and Gammaproteobacteria, and Bacteroidetes and not archaeal sequences. The phylotypes that displayed more than 97% similarity to the sequences obtained from the drilling mud fluids were defined as possible contaminants in this study and were detected as minor components of the bacterial phylotype compositions in 13 of 37 core samples. The degree of microbiological contamination was consistent with that determined by the PFT and/or microsphere assessments. This study suggests a constructive approach for evaluation and eliminating microbial contamination during riser-less drilling and coring operations by the D/V Chikyu. PMID:24265628

The first microbiological contamination assessment by deep-sea drilling and coring by the D/V Chikyu at the Iheya North hydrothermal field in the Mid-Okinawa Trough (IODP Expedition 331).

PubMed

Yanagawa, Katsunori; Nunoura, Takuro; McAllister, Sean M; Hirai, Miho; Breuker, Anja; Brandt, Leah; House, Christopher H; Moyer, Craig L; Birrien, Jean-Louis; Aoike, Kan; Sunamura, Michinari; Urabe, Tetsuro; Mottl, Michael J; Takai, Ken

2013-01-01

During the Integrated Ocean Drilling Program (IODP) Expedition 331 at the Iheya North hydrothermal system in the Mid-Okinawa Trough by the D/V Chikyu, we conducted microbiological contamination tests of the drilling and coring operations. The contamination from the drilling mud fluids was assessed using both perfluorocarbon tracers (PFT) and fluorescent microsphere beads. PFT infiltration was detected from the periphery of almost all whole round cores (WRCs). By contrast, fluorescent microspheres were not detected in hydrothermally active core samples, possibly due to thermal decomposition of the microspheres under high-temperature conditions. Microbial contamination from drilling mud fluids to the core interior subsamples was further characterized by molecular-based evaluation. The microbial 16S rRNA gene phylotype compositions in the drilling mud fluids were mainly composed of sequences of Beta- and Gammaproteobacteria, and Bacteroidetes and not archaeal sequences. The phylotypes that displayed more than 97% similarity to the sequences obtained from the drilling mud fluids were defined as possible contaminants in this study and were detected as minor components of the bacterial phylotype compositions in 13 of 37 core samples. The degree of microbiological contamination was consistent with that determined by the PFT and/or microsphere assessments. This study suggests a constructive approach for evaluation and eliminating microbial contamination during riser-less drilling and coring operations by the D/V Chikyu.

Characterization of heavy-metal-contaminated sediment by using unsupervised multivariate techniques and health risk assessment.

PubMed

Wang, Yeuh-Bin; Liu, Chen-Wuing; Wang, Sheng-Wei

2015-03-01

This study characterized the sediment quality of the severely contaminated Erjen River in Taiwan by using multivariate analysis methods-including factor analysis (FA), self-organizing maps (SOMs), and positive matrix factorization (PMF)-and health risk assessment. The SOMs classified the dataset with similar heavy-metal-contaminated sediment into five groups. FA extracted three major factors-traditional electroplating and metal-surface processing factor, nontraditional heavy-metal-industry factor, and natural geological factor-which accounted for 80.8% of the variance. The SOMs and FA revealed the heavy-metal-contaminated-sediment hotspots in the middle and upper reaches of the major tributary in the dry season. The hazardous index value for health risk via ingestion was 0.302. PMF further qualified the source apportionment, indicating that traditional electroplating and metal-surface-processing industries comprised 47% of the health risk posed by heavy-metal-contaminated sediment. Contaminants discharged from traditional electroplating and metal-surface-processing industries in the middle and upper reaches of the major tributary must be eliminated first to improve the sediment quality in Erjen River. The proposed assessment framework for heavy-metal-contaminated sediment can be applied to contaminated-sediment river sites in other regions. Copyright © 2014 Elsevier Inc. All rights reserved.

Risk Assessment of Groundwater Contamination: A Multilevel Fuzzy Comprehensive Evaluation Approach Based on DRASTIC Model

PubMed Central

Zhang, Yan; Zhong, Ming

2013-01-01

Groundwater contamination is a serious threat to water supply. Risk assessment of groundwater contamination is an effective way to protect the safety of groundwater resource. Groundwater is a complex and fuzzy system with many uncertainties, which is impacted by different geological and hydrological factors. In order to deal with the uncertainty in the risk assessment of groundwater contamination, we propose an approach with analysis hierarchy process and fuzzy comprehensive evaluation integrated together. Firstly, the risk factors of groundwater contamination are identified by the sources-pathway-receptor-consequence method, and a corresponding index system of risk assessment based on DRASTIC model is established. Due to the complexity in the process of transitions between the possible pollution risks and the uncertainties of factors, the method of analysis hierarchy process is applied to determine the weights of each factor, and the fuzzy sets theory is adopted to calculate the membership degrees of each factor. Finally, a case study is presented to illustrate and test this methodology. It is concluded that the proposed approach integrates the advantages of both analysis hierarchy process and fuzzy comprehensive evaluation, which provides a more flexible and reliable way to deal with the linguistic uncertainty and mechanism uncertainty in groundwater contamination without losing important information. PMID:24453883

The use of the Molecular Adsorber Coating technology to mitigate vacuum chamber contamination during Pathfinder testing for the James Webb Space Telescope

NASA Astrophysics Data System (ADS)

Abraham, Nithin S.; Hasegawa, Mark M.; Wooldridge, Eve M.; Henderson-Nelson, Kelly A.

2016-09-01

As a coating made of highly porous zeolite materials, the Molecular Adsorber Coating (MAC) was developed to capture outgassed molecular contaminants, such as hydrocarbons and silicones. For spaceflight applications, the adsorptive capabilities of the coating can alleviate on-orbit outgassing concerns on or near sensitive surfaces and instruments within the spacecraft. Similarly, this sprayable paint technology has proven to be significantly beneficial for ground based space applications, in particular, for vacuum chamber environments. This paper describes the recent use of the MAC technology during Pathfinder testing of the Optical Ground Support Equipment (OGSE) for the James Webb Space Telescope (JWST) at NASA Johnson Space Center (JSC). The coating was used as a mitigation tool to entrap persistent outgassed contaminants, specifically silicone based diffusion pump oil, from within JSC's cryogenic optical vacuum chamber test facility called Chamber A. This paper summarizes the sample fabrication, installation, laboratory testing, post-test chemical analysis results, and future plans for the MAC technology, which was effectively used to protect the JWST test equipment from vacuum chamber contamination.

The Use of the Molecular Adsorber Coating Technology to Mitigate Vacuum Chamber Contamination During Pathfinder Testing for the James Webb Space Telescope

NASA Technical Reports Server (NTRS)

Abraham, Nithin S.; Hasegawa, Mark M.; Wooldridge, Eve M.; Henderson-Nelson, Kelly A.

2016-01-01

As a coating made of highly porous zeolite materials, the Molecular Adsorber Coating (MAC) was developed to capture outgassed molecular contaminants, such as hydrocarbons and silicones. For spaceflight applications, the adsorptive capabilities of the coating can alleviate on-orbit outgassing concerns on or near sensitive surfaces and instruments within the spacecraft. Similarly, this sprayable paint technology has proven to be significantly beneficial for ground based space applications, in particular, for vacuum chamber environments. This paper describes the recent use of the MAC technology during Pathfinder testing of the Optical Ground Support Equipment (OGSE) for the James Webb Space Telescope (JWST) at NASA Johnson Space Center (JSC). The coating was used as a mitigation tool to entrap persistent outgassed contaminants, specifically silicone based diffusion pump oil, from within JSC's cryogenic optical vacuum chamber test facility called Chamber A. This paper summarizes the sample fabrication, installation, laboratory testing, post-test chemical analysis results, and future plans for the MAC technology, which was effectively used to protect the JWST test equipment from vacuum chamber contamination.

Consumer product in vitro digestion model: Bioaccessibility of contaminants and its application in risk assessment.

PubMed

Brandon, Esther F A; Oomen, Agnes G; Rompelberg, Cathy J M; Versantvoort, Carolien H M; van Engelen, Jacqueline G M; Sips, Adrienne J A M

2006-03-01

This paper describes the applicability of in vitro digestion models as a tool for consumer products in (ad hoc) risk assessment. In current risk assessment, oral bioavailability from a specific product is considered to be equal to bioavailability found in toxicity studies in which contaminants are usually ingested via liquids or food matrices. To become bioavailable, contaminants must first be released from the product during the digestion process (i.e. become bioaccessible). Contaminants in consumer products may be less bioaccessible than contaminants in liquid or food. Therefore, the actual risk after oral exposure could be overestimated. This paper describes the applicability of a simple, reliable, fast and relatively inexpensive in vitro method for determining the bioaccessibility of a contaminant from a consumer product. Different models, representing sucking and/or swallowing were developed. The experimental design of each model can be adjusted to the appropriate exposure scenarios as determined by the risk assessor. Several contaminated consumer products were tested in the various models. Although relevant in vivo data are scare, we succeeded to preliminary validate the model for one case. This case showed good correlation and never underestimated the bioavailability. However, validation check needs to be continued.

Hierarchical Bayesian models to assess between- and within-batch variability of pathogen contamination in food.

PubMed

Commeau, Natalie; Cornu, Marie; Albert, Isabelle; Denis, Jean-Baptiste; Parent, Eric

2012-03-01

Assessing within-batch and between-batch variability is of major interest for risk assessors and risk managers in the context of microbiological contamination of food. For example, the ratio between the within-batch variability and the between-batch variability has a large impact on the results of a sampling plan. Here, we designed hierarchical Bayesian models to represent such variability. Compatible priors were built mathematically to obtain sound model comparisons. A numeric criterion is proposed to assess the contamination structure comparing the ability of the models to replicate grouped data at the batch level using a posterior predictive loss approach. Models were applied to two case studies: contamination by Listeria monocytogenes of pork breast used to produce diced bacon and contamination by the same microorganism on cold smoked salmon at the end of the process. In the first case study, a contamination structure clearly exists and is located at the batch level, that is, between batches variability is relatively strong, whereas in the second a structure also exists but is less marked. © 2012 Society for Risk Analysis.

Food and feed chemical contaminants in the European Union: Regulatory, scientific, and technical issues concerning chemical contaminants occurrence, risk assessment, and risk management in the European Union.

PubMed

Silano, Marco; Silano, Vittorio

2017-07-03

A priority of the European Union is the control of risks possibly associated with chemical contaminants in food and undesirable substances in feed. Following an initial chapter describing the main contaminants detected in food and undesirable substances in feed in the EU, their main sources and the factors which affect their occurrence, the present review focuses on the "continous call for data" procedure that is a very effective system in place at EFSA to make possible the exposure assessment of specific contaminants and undesirable substances. Risk assessment of contaminants in food atances in feed is carried currently in the European Union by the CONTAM Panel of EFSA according to well defined methodologies and in collaboration with competent international organizations and with Member States.

Public health risk assessment of groundwater contamination in Batman, Turkey.

PubMed

Nalbantcilar, M Tahir; Pinarkara, Sukru Yavuz

2016-08-01

In this study, a comprehensive analysis of groundwater was performed to assess contamination and phenol content in Batman, Turkey, particularly in residential areas near agriculture, livestock and oil industry facilities. From these areas, where potentially contaminated groundwater used for drinking and irrigation threatens public health, 30 groundwater samples were collected and analyzed for heavy metal concentrations (Al, As, B, Ba, Ca, Cd, Cl, Co, Cr, Cu, Fe, Hg, Li, Mg, Mn, Mo, Na, Ni, NO3, P, Pb, phenol, S, Sb, Se, SO4, Sr, U, and Zn). Compared with the standards of the Environmental Protection Agency, Al, Fe, and Mn concentrations in groundwater exceeded secondary drinking water regulations, NO3 concentrations were high for maximum contaminant levels, and As, Pb, and U concentrations exceeded maximum contaminant level goals in all samples. Ni, Sb, and Se concentrations also exceeded limits set by the Turkish Standards Institution. Nearly all samples revealed concentrations of Se, Sb, Hg, and phenol due to nearby petroleum refineries, oil storage plants, and agricultural and livestock areas. The results obtained from this study indicate that the groundwater in Batman contains elements in concentrations that approach or exceed limits and thus threatens public health with increased blood cholesterol, decreased blood sugar, and circulatory problems.

The effects of moisture on molecular sieve oxygen concentrators.

PubMed

Ikels, K G; Theis, C F

1985-01-01

Molecular sieve oxygen generating systems are receiving extensive laboratory and flight evaluation. Assessment of the molecular system has generally been conducted in the laboratory using clean dry air. In aircraft, however, the molecular sieve generator is supplied with engine bleed air which may not always be totally free of contaminants and water. Recent studies using bed washout technics have shown that the molecular sieve units, with 50% of the beds deactivated with water, still function normally with respect to product gas flow and O2 concentration. By utilizing the technics described in this paper, the moisture content or state of hydration of the molecular sieve can readily be determined.

Soil risk assessment of As and Zn contamination in a coal mining region using geostatistics [corrected].

PubMed

Komnitsas, Kostas; Modis, Kostas

2006-12-01

The present paper aims to map As and Zn contamination and assess the risk for agricultural soils in a wider disposal site containing wastes derived from coal beneficiation. Geochemical data related to environmental studies show that the waste characteristics favor solubilisation and mobilization of inorganic contaminants and in some cases the generation of acidic leachates. 135 soil samples were collected from a 34 km(2) area and analysed by using geostatistics under the maximum entropy principle in order to produce risk assessment maps and estimate the probability of soil contamination. In addition, the present paper discusses the main issues related to risk assessment in wider mining and waste disposal sites in order to assist decision makers in selecting feasible rehabilitation schemes.

Chemical contamination in aquatic ecosystems.

PubMed

Iwata, Hisato; Kim, Eun-Young; Yamauchi, Masanobu; Inoue, Suguru; Agusa, Tetsuro; Tanabe, Shinsuke

2007-03-01

The 21st Century's Center of Excellence (COE) Program "Coastal Marine Environmental Research" in Ehime University, funded by the Ministry of Education, Culture, Sports, Science and Technology, Government of Japan, started its activities in October 2002. One of the core projects of the COE Program in Ehime University is "studies on environmental behavior of hazardous chemicals and their toxic effects on wildlife". This core project deals with studies of the local and global distribution of environmental contaminants in aquatic ecosystems, retrospective analysis of such chemicals, their toxicokinetics in humans and wildlife, molecular mechanisms to determine species-specific reactions, and sensitivity of chemically induced effects, and with the development of methodology for risk assessment for the conservation of ecological and species diversity. This presentation describes our recent achievements of this project, including research on contamination by arsenic and organohalogen pollutants in the Mekong River basin and molecular mechanisms of morphologic deformities in dioxin-exposed red seabream (Pagrus major) embryos. We established the Environmental Specimen Bank (es-BANK) in Ehime University in 2004, archiving approximately 100000 cryogenic samples containing tissues of wildlife and humans that have been collected for the past 40 years. The CMES homepage offers details of samples through online database retrieval. The es-BANK facility was in operation by the end of 2005.

THE ONSITE ON-LINE CALCULATORS AND TRAINING FOR SUBSURFACE CONTAMINANT TRANSPORT SITE ASSESSMENT

EPA Science Inventory

EPA has developed a suite of on-line calculators called "OnSite" for assessing transport of environmental contaminants in the subsurface. The purpose of these calculators is to provide methods and data for common calculations used in assessing impacts from subsurface contaminatio...

Fungal Peptaibiotics: Assessing Potential Meteoritic Amino Acid Contamination

NASA Technical Reports Server (NTRS)

Elsila, J. E.; Callahan, M. P.; Glavin, D. P.; Dworkin, J. P.; Bruckner, H.

2010-01-01

The presence of non-protein alpha-dialkyl-amino acids such as alpha-aminoisobutyric acid (alpha-A1B) and isovaline (Iva), which are relatively rare in the terrestrial biosphere, has long been used as an indication of the indigeneity of meteoritic amino acids, however, the discovery of alpha-AIB in peptides producers by a widespread group of filamentous fungi indicates the possibility of a terrestrial biotic source for the alpha-AIB observed in some meteorites. The alpha-AIB-containing peptides produced by these fungi are dubbed peptaibiotics. We measured the molecular distribution and stable carbon and nitrogen isotopic ratios for amino acids found in the total hydrolysates of four biologically synthesized peptaibiotics. We compared these aneasurenetts with those from the CM2 carbonaceous chondrite Murchison and from three Antarctic CR2 carbonaceous chondrites in order to understand the peptaibiotics as a potential source of meteoritic contamination.

Contaminants as viral cofactors: assessing indirect population effects

USGS Publications Warehouse

Springman, Katherine R.; Kurath, Gael; Anderson, James J.; Emlen, John M.

2005-01-01

Current toxicological methods often miss contaminant effects, particularly when immune suppression is involved. The failure to recognize and evaluate indirect and sublethal effects severely limits the applicability of those methods at the population level. In this study, the Vitality model is used to evaluate the population level effects of a contaminant exerting only indirect, sublethal effects at the individual level. Juvenile rainbow trout (Oncorhynchus mykiss) were injected with 2.5 or 10.0 mg/kg doses of the model CYP1A inducer, β-naphthoflavone (BNF) as a pre-stressor, then exposed to a challenge dose of 102 or 104 pfu/fish of infectious hematopoietic necrosis virus (IHNV), an important viral pathogen of salmonids in North America. At the end of the 28-d challenge, the mortality data were processed according to the Vitality model which indicated that the correlation between the average rate of vitality loss and the pre-stressor dose was strong:R2 = 0.9944. Average time to death and cumulative mortality were dependent on the BNF dose, while no significant difference between the two viral dosages was shown, implying that the history of the organism at the time of stressor exposure is an important factor in determining the virulence or toxicity of the stressor. The conceptual framework of this model permits a smoother transfer of results to a more complex stratum, namely the population level, which allows the immunosuppressive results generated by doses of a CYP1A inducer that more accurately represent the effects elicited by environmentally-relevant contaminant concentrations to be extrapolated to target populations. The indirect effects of other environmental contaminants with similar biotransformation pathways, such as polycyclic aromatic hydrocarbons (PAH), could be assessed and quantified with this model and the results applied to a more complex biological hierarchy.

Characterization and Remediation of Contaminated Sites:Modeling, Measurement and Assessment

NASA Astrophysics Data System (ADS)

Basu, N. B.; Rao, P. C.; Poyer, I. C.; Christ, J. A.; Zhang, C. Y.; Jawitz, J. W.; Werth, C. J.; Annable, M. D.; Hatfield, K.

2008-05-01

small computation time and their inclusion of spatially integrated parameters that can be measured in the field using tracer tests. Analytical models that couple source depletion to plume transport were used for optimization of source and plume treatment. These models are being used for the development of decision and management tools (for DNAPL sites) that consider uncertainty assessments as an integral part of the decision-making process for contaminated site remediation.

Equilibrium Partitioning Approach for Assessing Toxicity of Contaminants in Sediments: Linking Measured Concentrations to Effects

EPA Science Inventory

A variety of approaches exist for assessing the degree, extent and/or risk of metals contamination in sediments. Selection of the “correct” approach depends on the nature of the question being asked (e.g., the degree of metals contamination in marine sediments may be estimated by...

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.

Contaminant gradients in trees: Directional tree coring reveals boundaries of soil and soil-gas contamination with potential applications in vapor intrusion assessment

USGS Publications Warehouse

Wilson, Jordan L.; Samaranayake, V.A.; Limmer, Matthew A.; Schumacher, John G.; Burken, Joel G.

2017-01-01

Contaminated sites pose ecological and human-health risks through exposure to contaminated soil and groundwater. Whereas we can readily locate, monitor, and track contaminants in groundwater, it is harder to perform these tasks in the vadose zone. In this study, tree-core samples were collected at a Superfund site to determine if the sample-collection location around a particular tree could reveal the subsurface location, or direction, of soil and soil-gas contaminant plumes. Contaminant-centroid vectors were calculated from tree-core data to reveal contaminant distributions in directional tree samples at a higher resolution, and vectors were correlated with soil-gas characterization collected using conventional methods. Results clearly demonstrated that directional tree coring around tree trunks can indicate gradients in soil and soil-gas contaminant plumes, and the strength of the correlations were directly proportionate to the magnitude of tree-core concentration gradients (spearman’s coefficient of -0.61 and -0.55 in soil and tree-core gradients, respectively). Linear regression indicates agreement between the concentration-centroid vectors is significantly affected by in-planta and soil concentration gradients and when concentration centroids in soil are closer to trees. Given the existing link between soil-gas and vapor intrusion, this study also indicates that directional tree coring might be applicable in vapor intrusion assessment.

Contaminant Gradients in Trees: Directional Tree Coring Reveals Boundaries of Soil and Soil-Gas Contamination with Potential Applications in Vapor Intrusion Assessment.

PubMed

Wilson, Jordan L; Samaranayake, V A; Limmer, Matthew A; Schumacher, John G; Burken, Joel G

2017-12-19

Contaminated sites pose ecological and human-health risks through exposure to contaminated soil and groundwater. Whereas we can readily locate, monitor, and track contaminants in groundwater, it is harder to perform these tasks in the vadose zone. In this study, tree-core samples were collected at a Superfund site to determine if the sample-collection location around a particular tree could reveal the subsurface location, or direction, of soil and soil-gas contaminant plumes. Contaminant-centroid vectors were calculated from tree-core data to reveal contaminant distributions in directional tree samples at a higher resolution, and vectors were correlated with soil-gas characterization collected using conventional methods. Results clearly demonstrated that directional tree coring around tree trunks can indicate gradients in soil and soil-gas contaminant plumes, and the strength of the correlations were directly proportionate to the magnitude of tree-core concentration gradients (spearman's coefficient of -0.61 and -0.55 in soil and tree-core gradients, respectively). Linear regression indicates agreement between the concentration-centroid vectors is significantly affected by in planta and soil concentration gradients and when concentration centroids in soil are closer to trees. Given the existing link between soil-gas and vapor intrusion, this study also indicates that directional tree coring might be applicable in vapor intrusion assessment.

Assessing Date Palm Genetic Diversity Using Different Molecular Markers.

PubMed

Atia, Mohamed A M; Sakr, Mahmoud M; Adawy, Sami S

2017-01-01

Molecular marker technologies which rely on DNA analysis provide powerful tools to assess biodiversity at different levels, i.e., among and within species. A range of different molecular marker techniques have been developed and extensively applied for detecting variability in date palm at the DNA level. Recently, the employment of gene-targeting molecular marker approaches to study biodiversity and genetic variations in many plant species has increased the attention of researchers interested in date palm to carry out phylogenetic studies using these novel marker systems. Molecular markers are good indicators of genetic distances among accessions, because DNA-based markers are neutral in the face of selection. Here we describe the employment of multidisciplinary molecular marker approaches: amplified fragment length polymorphism (AFLP), start codon targeted (SCoT) polymorphism, conserved DNA-derived polymorphism (CDDP), intron-targeted amplified polymorphism (ITAP), simple sequence repeats (SSR), and random amplified polymorphic DNA (RAPD) to assess genetic diversity in date palm.

Indirect methods of dried sewage sludge contamination assessments.

PubMed

Werle, Sebastian; Dudziak, Mariusz; Grübel, Klaudiusz

2016-07-28

Thermal conversion (combustion, co-combustion, gasification and pyrolysis) appears to be the most promising alternative for sewage sludge management in the future. Nevertheless, safe and ecological usage of sewage sludge as a fuel requires information about their contamination. The aim of this paper is to present the photoacoustic spectroscopy (PAS) as a good method for contamination assessments of dried sewage sludge. Two types of granular sewage sludge: Sewage sludge 1 (SS1) taken from Polish wastewater treatment plant operating in the mechanical-biological system and sewage sludge 2 (SS2) taken from mechanical-biological-chemical wastewater treatment plant with phosphorus precipitation were analysed. The spectrophotometer FTIR Nicolet 6700 equipped with photoacoustic cell (Model 300, MTEC, USA) was used. The comparison with the most popular analytical methods (GC-MS) was also done. The results of PAS studies confirm the difference between the SS1 and SS2 which is in agreement with the GC-MS analysis. Higher absorbance was observed at each wavelength characteristics for the oscillator of chemical moieties for the SS1 with respect to the SS2.

Assessing the external benefits of contaminated soil remediation in Korea: a choice experiment study.

PubMed

Lim, Seul-Ye; Kim, Hyo-Jin; Yoo, Seung-Hoon

2018-06-01

Korean government has made and will continue to make a considerable investment in contaminated soil remediation to rectify the problems that arise from soil pollution. Quantitative information on the benefits of contaminated soil remediation is widely demanded by the public as well as the government. This article aims to assess the external benefits of contaminated soil remediation. A survey of 1000 randomly selected households was undertaken in Korea. The results show that the marginal willingness to pay values for a 1% decrease in human health hazard, a 1% improvement in biodiversity restoration, and 1000 new job creation by contaminated soil remediation are estimated to be KRW 204 (USD 0.17), 593 (0.50), and 238 (0.20) per household per year. The findings can provide policy-makers with useful information for both evaluating and planning the contaminated soil remediation.

Assessment of Groundwater Vulnerability for Antropogenic and Geogenic Contaminants in Subwatershed

NASA Astrophysics Data System (ADS)

Ko, K.; Koh, D.; Chae, G.; Cheong, B.

2007-12-01

Groundwater is an important natural resource that providing drinking water to more than five million people in Korea. Nonpoint source nitrate was frequently observed contaminant and the investigation result for small potable water supply system that mainly consisted of 70 percent groundwater showed that about 5 percent of water samples exceeded potable water quality standards of Korea. The geogenic contanminants such as arsenic and fluoride also frequently observed contaminants in Korea. In order to protect groundwater and to supply safe water to public, we need to assess groundwater vulnerability and to know the cause of occurrence of contaminants. To achieve this goal, we executed groundwater investigation and assessment study for Keumsan subwatershed with 600km2 in Keum-river watershed. The geostatistical and GIS technique were applied to map the spatial distribution of each contaminants and to calculate vulnerability index. The results of logistic regression for nitrate indicated the close relationship with land use. The results of hydrogeochemical analyses showed that nitrates in groundwater are largely influenced by land use and had high values in granitic region with dense agricultural field and resident. The high nitrates are closely related to groundwater of greenhouse area where large amount of manure and fertilizer were usually introduced in cultural land. The soil in granitic region had high contents of permeable sand of weathered products of granite that play as a role of pathway of contaminants in agricultural land and resident area. The high values of bicarbonate are originated from two sources, limestone dissolution of Ogcheon belt and biodegradation organic pollutants from municipal wastes in granitic region with dense agriculture and residence. It is considered that the anomalous distribution of arsenic and fluoride is related to limestone and metasedimentry rock of Ogcheon belt with high contents of sulfide minerals and F bearing minerals. The

Determination of a risk management primer at petroleum-contaminated sites: developing new human health risk assessment strategy.

PubMed

Park, In-Sun; Park, Jae-Woo

2011-01-30

Total petroleum hydrocarbon (TPH) is an important environmental contaminant that is toxic to human and environmental receptors. However, human health risk assessment for petroleum, oil, and lubricant (POL)-contaminated sites is especially challenging because TPH is not a single compound, but rather a mixture of numerous substances. To address this concern, this study recommends a new human health risk assessment strategy for POL-contaminated sites. The strategy is based on a newly modified TPH fractionation method and includes an improved analytical protocol. The proposed TPH fractionation method is composed of ten fractions (e.g., aliphatic and aromatic EC8-10, EC10-12, EC12-16, EC16-22 and EC22-40). Physicochemical properties and toxicity values of each fraction were newly defined in this study. The stepwise ultrasonication-based analytical process was established to measure TPH fractions. Analytical results were compared with those from the TPH Criteria Working Group (TPHCWG) Direct Method. Better analytical efficiencies in TPH, aliphatic, and aromatic fractions were achieved when contaminated soil samples were analyzed with the new analytical protocol. Finally, a human health risk assessment was performed based on the developed tiered risk assessment framework. Results showed that a detailed quantitative risk assessment should be conducted to determine scientifically and economically appropriate cleanup target levels, although the phase II process is useful for determining the potency of human health risks posed by POL-contamination. Copyright © 2010 Elsevier B.V. All rights reserved.

Assessing nickel bioavailability in smelter-contaminated soils.

PubMed

Everhart, Jeffrey L; McNear, David; Peltier, Edward; van der Lelie, Daniel; Chaney, Rufus L; Sparks, Donald L

2006-08-31

Metal contaminants in soil environments derived from industrial pollution have clearly established the need for research on bioavailability and potential health risks. Much research has been conducted on metal sorption in soils. However, there is still a need to better understand the availability of metal contaminants to plants and microbes. Such information will enhance both human health and decisions about remediation efforts. In this study, Welland Loam (Typic epiaquoll) and Quarry Muck (Terric haplohemist) Ni contaminated soils from Port Colborne (Canada) which had been treated and untreated with limestone, were employed in greenhouse and bioavailability studies. These soils varied in pH from 5.1 to 7.5, in organic matter content from 6% to 72%, and in total Ni from 63 to 22,000 mg/kg. Oat (Avena sativa), a nonhyperaccumulator, and Alyssum murale, a hyperaccumulating plant species, were grown on these soils in greenhouse studies for 45 and 120 days, respectively, to estimate Ni accumulation. A Ni specific bacterial biosensor was also used to determine Ni bioavailability, and the results were compared to those from the greenhouse studies and more conventional, indirect chemical extraction techniques (employing MgCl2 and a Sr(NO3)2). Results from the greenhouse, chemical extraction, and biosensor studies suggested that as the pH of the soil was increased with liming, Ni bioavailability decreased. However, the phytoextraction capability of A. murale increased as soil pH increased, which was not the case for A. sativa. Furthermore, the Ni specific bacterial biosensor was successful in predicting Ni bioavailability in the soils and suggested that higher Ni bioavailabilities occur in the soils at pH values of 5.1 and 6. The combination of plant growth, chemical extraction, and bacterial biosensor approaches are recommended for assessing bioavailability of toxic metals.

The rationale for simple approaches for sustainability assessment and management in contaminated land practice.

PubMed

Bardos, R Paul; Bone, Brian D; Boyle, Richard; Evans, Frank; Harries, Nicola D; Howard, Trevor; Smith, Jonathan W N

2016-09-01

The scale of land-contamination problems, and of the responses to them, makes achieving sustainability in contaminated land remediation an important objective. The Sustainable Remediation Forum in the UK (SuRF-UK) was established in 2007 to support more sustainable remediation practice in the UK. The current international interest in 'sustainable remediation' has achieved a fairly rapid consensus on concepts, descriptions and definitions for sustainable remediation, which are now being incorporated into an ISO standard. However the sustainability assessment methods being used remain diverse with a range of (mainly) semi-quantitative and quantitative approaches and tools developed, or in development. Sustainability assessment is site specific and subjective. It depends on the inclusion of a wide range of considerations across different stakeholder perspectives. Taking a tiered approach to sustainability assessment offers important advantages, starting from a qualitative assessment and moving through to semi-quantitative and quantitative assessments on an 'as required' basis only. It is also clear that there are a number of 'easy wins' that could improve performance against sustainability criteria right across the site management process. SuRF-UK has provided a checklist of 'sustainable management practices' that describes some of these. This paper provides the rationale for, and an outline of, and recently published SuRF-UK guidance on preparing for and framing sustainability assessments; carrying out qualitative sustainability assessment; and simple good management practices to improve sustainability across contaminated land management activities. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

Culture-based indicators of fecal contamination and molecular microbial indicators rarely correlate with Campylobacter spp. in recreational waters.

PubMed

Hellein, Kristen N; Battie, Cynthia; Tauchman, Eric; Lund, Deanna; Oyarzabal, Omar A; Lepo, Joe Eugene

2011-12-01

Campylobacter spp. are the leading cause of gastroenteritis worldwide. Most human infections result from contaminated food; however, infections are also caused by recreational waterway contamination. Campylobacter culture is technically challenging and enumeration by culture-based methods is onerous. Thus, we employed qPCR to quantify Campylobacter spp. in fresh- and marine-water samples, raw sewage and animal feces. Multiplex PCR determined whether Campylobacter jejuni or C. coli, most commonly associated with human disease, were present in qPCR-positive samples. Campylobacters were detected in raw sewage, and in feces of all avian and mammalian species tested. Campylobacter-positive concentrations ranged from 68 to 2.3 × 10⁶ cells per 500 mL. Although C. jejuni and C. coli were rare in waterways, they were prevalent in sewage and feces. Campylobacter-specific qPCR screening of environmental waters did not correlate with the regulatory EPA method 1600 (Enterococcus culture), nor with culture-independent, molecular-based microbial source tracking indicators, such as human polyomavirus, human Bacteroidales and Methanobrevibacter smithii. Our results suggest that neither the standard EPA method nor the newly proposed culture-independent methods are appropriate surrogates for Campylobacter contamination in water. Thus, assays for specific pathogens may be necessary to protect human health, especially in waters that are contaminated with sewage and animal feces.

A Diagnostic Assessment for Introductory Molecular and Cell Biology

PubMed Central

Wood, William B.; Martin, Jennifer M.; Guild, Nancy A.; Vicens, Quentin; Knight, Jennifer K.

2010-01-01

We have developed and validated a tool for assessing understanding of a selection of fundamental concepts and basic knowledge in undergraduate introductory molecular and cell biology, focusing on areas in which students often have misconceptions. This multiple-choice Introductory Molecular and Cell Biology Assessment (IMCA) instrument is designed for use as a pre- and posttest to measure student learning gains. To develop the assessment, we first worked with faculty to create a set of learning goals that targeted important concepts in the field and seemed likely to be emphasized by most instructors teaching these subjects. We interviewed students using open-ended questions to identify commonly held misconceptions, formulated multiple-choice questions that included these ideas as distracters, and reinterviewed students to establish validity of the instrument. The assessment was then evaluated by 25 biology experts and modified based on their suggestions. The complete revised assessment was administered to more than 1300 students at three institutions. Analysis of statistical parameters including item difficulty, item discrimination, and reliability provides evidence that the IMCA is a valid and reliable instrument with several potential uses in gauging student learning of key concepts in molecular and cell biology. PMID:21123692

In vitro evaluation of microbial contamination of orthodontic brackets as received from the manufacturer using microbiological and molecular tests.

PubMed

Dos Santos Gerzson, Darlene R; Simon, Daniel; Dos Anjos, Aline Lima; Freitas, Maria Perpétua Mota

2015-11-01

To test the null hypothesis that orthodontic brackets as supplied by manufacturers do not have microbial contamination. The sample comprised 140 brackets of four different commercially available brands, used directly from the manufacturer's packaging, divided into 14 groups (n  =  10 brackets each). Of the 140 pieces, 60 were full cases and 80 were replacement brackets. Materials were tested to detect bacterial growth, analyze types of bacteria present (biochemical test), and identify bacteria (molecular test with polymerase chain reaction [PCR]). In two of 12 groups the brackets showed microbial contamination: group 1, Morelli full case brackets, and group 12, Abzil-3M Unitek replacement brackets. Staphylococcus aureus and Staphylococcus epidermidis were the bacteria identified in groups 1 and 12, respectively (suggested by the biochemical test and confirmed by PCR). Brackets of two brands (Morelli and Abzil-3M Unitek) were found to be contaminated by bacteria in the original packages supplied by the manufacturers, which suggests a risk for patient contamination. These data suggest that the manufacturers of these materials should improve the quality control of the packaging used, including sterilization, for the security of patient health.

Contamination assessment in microbiological sampling of the Eyreville core, Chesapeake Bay impact structure

USGS Publications Warehouse

Gronstal, A.L.; Voytek, M.A.; Kirshtein, J.D.; Von der, Heyde; Lowit, M.D.; Cockell, C.S.

2009-01-01

Knowledge of the deep subsurface biosphere is limited due to difficulties in recovering materials. Deep drilling projects provide access to the subsurface; however, contamination introduced during drilling poses a major obstacle in obtaining clean samples. To monitor contamination during the 2005 International Continental Scientific Drilling Program (ICDP)-U.S. Geological Survey (USGS) deep drilling of the Chesapeake Bay impact structure, four methods were utilized. Fluorescent microspheres were used to mimic the ability of contaminant cells to enter samples through fractures in the core material during retrieval. Drilling mud was infused with a chemical tracer (Halon 1211) in order to monitor penetration of mud into cores. Pore water from samples was examined using excitation-emission matrix (EEM) fl uorescence spectroscopy to characterize dissolved organic carbon (DOC) present at various depths. DOC signatures at depth were compared to signatures from drilling mud in order to identify potential contamination. Finally, microbial contaminants present in drilling mud were identified through 16S ribosomal deoxyribonucleic acid (rDNA) clone libraries and compared to species cultured from core samples. Together, these methods allowed us to categorize the recovered core samples according to the likelihood of contamination. Twenty-two of the 47 subcores that were retrieved were free of contamination by all the methods used and were subsequently used for microbiological culture and culture-independent analysis. Our approach provides a comprehensive assessment of both particulate and dissolved contaminants that could be applied to any environment with low biomass. ?? 2009 The Geological Society of America.

A national level assessment of metal contamination in bats.

PubMed

Hernout, Béatrice V; Arnold, Kathryn E; McClean, Colin J; Walls, Michael; Baxter, Malcolm; Boxall, Alistair B A

2016-07-01

Many populations of bat species across the globe are declining, with chemical contamination one of many potential stressors implicated in these demographic changes. Metals still contaminate a wide range of habitats, but the risks to bats remain poorly understood. This study is the first to present a national scale assessment of toxic metal (Cd, Pb) and essential trace metal (Cu, Zn) concentrations in bats. Metal concentrations in tissues (kidneys, liver, stomach -stomach content, bones and fur) were measured in 193 Pipistrellus sp. in England and Wales using ICP-MS, and compared to critical toxic concentrations for small mammals. The concentrations of metals determined in bat tissues were generally lower than those reported elsewhere. Strong positive associations were found between concentrations in tissues for a given metal (liver and kidneys for Cd, Cu and Pb; stomach and fur and fur and bones for Pb), suggesting recent as well as long term exposure to these contaminants. In addition, positive correlations between concentrations of different metals in the same tissues (Cd and Zn, Cu and Zn, Cd and Pb, Pb and Zn) suggest a co-exposure of metals to bats. Approximately 21% of the bats sampled contained residues of at least one metal at concentrations high enough to elicit toxic effects (associated with kidney damage), or to be above the upper level measured in other mammal species. Pb was found to pose the greatest risk (with 7-11% of the bats containing concentrations of toxicological concern), followed by Cu (4-9%), Zn (0.5-5.2%) and Cd (0%). Our data suggest that leaching of metals into our storage matrix, formaldehyde, may have occurred, especially for Cu. The overall findings suggest that metal contamination is an environmental stressor affecting bat populations, and that further research is needed into the direct links between metal contamination and bat population declines worldwide. Copyright © 2016 Elsevier Ltd. All rights reserved.

Assessing Groundwater Contamination Vulnerability at Public Water Supply Wells in California

NASA Astrophysics Data System (ADS)

Moran, J. E.; Hudson, B.; Dooher, B. P.; Leif, R.; Eaton, G. F.; Davisson, L.

2001-12-01

The California Aquifer Susceptibility project, sponsored by the California State Water Resources Control Board, uses a probabilistic approach to assess the vulnerability of public water supply wells to contamination by anthropogenic compounds. Sources of contamination to groundwater occur near the earth's surface, and have been present mostly since WWII. Therefore, wells that receive water that has recharged in the recent past are more likely to intercept contaminants transported by advection. The parameters that the study uses to rank wells according to vulnerability are groundwater age dates (using the tritium/helium method), stable isotopes of the water molecule (for water source determination), and analysis of low level Volatile Organic Compounds (VOCs). Results of a pilot project in which 300 public water supply wells were tested for vulnerability will be presented. Basins sampled for the study include the Livermore Valley, Santa Clara Valley, and the Sacramento Basin. Methyl-tertiary-Butyl Ether (MTBE) may be a useful time marker in groundwater basins, with water recharged after the 1980's showing traces of MTBE. Low-level detections of other VOCs such as TCE and PCE can give an early warning of a contaminant plume. When employed on a basin-scale, groundwater ages are an effective tool for identifying recharge areas, defining flowpaths, and determining the rate of transport of water and associated contaminants. Examination of these parameters also helps identify 'short circuits', whereby e.g., loss of integrity in well casing allows near surface contamination to reach 'old' (recharged >50 years ago) water. This work was performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under contract No. W-7405-ENG-48.

Assessment of post-contamination treatments affecting different bonding stages to dentin

PubMed Central

Elkassas, Dina; Arafa, Abla

2016-01-01

Objectives: To assess the effect of cleansing treatments following saliva and blood contamination at different bonding stages to dentin. Materials and Methods: Labial surfaces of 168 permanent maxillary central incisors were ground flat exposing superficial dentin. Specimens were divided into: uncontaminated control (A), contamination after etching (B), contamination after adhesive application (C), contamination after adhesive polymerization (D). Groups were further subdivided according to cleansing treatments into: rinsing (B1, C1, D1), re-etching (B2, D3), sodium hypochlorite application (B3), ethyl alcohol application (C2), acetone application (C3), rinsing and rebonding (D2), re-etching and rebonding (D4). Composite microcylinders were bonded to treated substrates and shear loaded micro-shear bond strength (μSBS) until failure and treated surfaces were examined with scanning electron microscope. Debonded surfaces were classified as adhesive, cohesive or mixed failure. The data were analyzed using one-way ANOVA and Tukey's post hoc test. Results: The μSBS values were ranked as follow; Group B: A > B3 > B2 > B1 > B, Group C: A > C3 > C2 > C1 > C, Group D: A > D4 > D1 = D2 ≥ D3. Debonded surfaces showed adhesive failure in Group B while cohesive failure in Groups C and D. Conclusions: Cleansing treatments differ according to bonding step; re-etching then rebonding suggested if etched substrate or polymerized adhesive were contaminated while acetone application decontaminated affected unpolymerized adhesive. PMID:27403048

Contaminants assessment in the coral reefs of Virgin Islands National Park and Virgin Islands Coral Reef National Monument

USGS Publications Warehouse

Bargar, Timothy A.; Garrison, Virginia H.; Alvarez, David A.; Echols, Kathy

2013-01-01

Coral, fish, plankton, and detritus samples were collected from coral reefs in Virgin Islands National Park (VIIS) and Virgin Islands Coral Reef National Monument (VICR) to assess existing contamination levels. Passive water sampling using polar organic chemical integrative samplers (POCIS) and semi-permeable membrane devices found a few emerging pollutants of concern (DEET and galaxolide) and polynuclear aromatic hydrocarbons. Very little persistent organic chemical contamination was detected in the tissue or detritus samples. Detected contaminants were at concentrations below those reported to be harmful to aquatic organisms. Extracts from the POCIS were subjected to the yeast estrogen screen (YES) to assess potential estrogenicity of the contaminant mixture. Results of the YES (estrogen equivalency of 0.17–0.31 ng/L 17-β-estradiol) indicated a low estrogenicity likelihood for contaminants extracted from water. Findings point to low levels of polar and non-polar organic contaminants in the bays sampled within VICR and VIIS.

ASSESSING CONTAMINANT SENSITIVITY OF ENDANGERED AND THREATENED SPECIES: 3. EFFLUENT TOXICITY TESTS

EPA Science Inventory

Dwyer, F. James, Douglas K. Hardesty, Christopher E. Henke, Christopher G. Ingersoll, David W. Whites, Tom Augspurger, Timothy J. Canfield, David R. Mount and Foster L. Mayer. Submitted. Assessing Contaminant Sensitivity of Endangered and Threatened Species: 3. Effluent Tests. Ar...

Assessment of Anaerobic Metabolic Activity and Microbial Diversity in a Petroleum-Contaminated Aquifer Using Push-Pull Tests in Combination With Molecular Tools and Stable Isotopes

NASA Astrophysics Data System (ADS)

Schroth, M. H.; Kleikemper, J.; Pombo, S. A.; Zeyer, J.

2002-12-01

In the past, studies on microbial communities in natural environments have typically focused on either their structure or on their metabolic function. However, linking structure and function is important for understanding microbial community dynamics, in particular in contaminated environments. We will present results of a novel combination of a hydrogeological field method (push-pull tests) with molecular tools and stable isotope analysis, which was employed to quantify anaerobic activities and associated microbial diversity in a petroleum-contaminated aquifer in Studen, Switzerland. Push-pull tests consisted of the injection of test solution containing a conservative tracer and reactants (electron acceptors, 13C-labeled carbon sources) into the aquifer anoxic zone. Following an incubation period, the test solution/groundwater mixture was extracted from the same location. Metabolic activities were computed from solute concentrations measured during extraction. Simultaneously, microbial diversity in sediment and groundwater was characterized by using fluorescence in situ hybridization (FISH), denaturing gradient gel electrophoresis (DGGE), as well as phospholipids fatty acid (PLFA) analysis in combination with 13C isotopic measurements. Results from DGGE analyses provided information on the general community structure before, during and after the tests, while FISH yielded information on active populations. Moreover, using 13C-labeling of microbial PLFA we were able to directly link carbon source assimilation in an aquifer to indigenous microorganisms while providing quantitative information on respective carbon source consumption.

Transport mechanisms of contaminants released from fine sediment in rivers

NASA Astrophysics Data System (ADS)

Cheng, Pengda; Zhu, Hongwei; Zhong, Baochang; Wang, Daozeng

2015-12-01

Contaminants released from sediment into rivers are one of the main problems to study in environmental hydrodynamics. For contaminants released into the overlying water under different hydrodynamic conditions, the mechanical mechanisms involved can be roughly divided into convective diffusion, molecular diffusion, and adsorption/desorption. Because of the obvious environmental influence of fine sediment (D_{90}= 0.06 mm), non-cohesive fine sediment, and cohesive fine sediment are researched in this paper, and phosphorus is chosen for a typical adsorption of a contaminant. Through theoretical analysis of the contaminant release process, according to different hydraulic conditions, the contaminant release coupling mathematical model can be established by the N-S equation, the Darcy equation, the solute transport equation, and the adsorption/desorption equation. Then, the experiments are completed in an open water flume. The simulation results and experimental results show that convective diffusion dominates the contaminant release both in non-cohesive and cohesive fine sediment after their suspension, and that they contribute more than 90 % of the total release. Molecular diffusion and desorption have more of a contribution for contaminant release from unsuspended sediment. In unsuspension sediment, convective diffusion is about 10-50 times larger than molecular diffusion during the initial stages under high velocity; it is close to molecular diffusion in the later stages. Convective diffusion is about 6 times larger than molecular diffusion during the initial stages under low velocity, it is about a quarter of molecular diffusion in later stages, and has a similar level with desorption/adsorption. In unsuspended sediment, a seepage boundary layer exists below the water-sediment interface, and various release mechanisms in that layer mostly dominate the contaminant release process. In non-cohesive fine sediment, the depth of that layer increases linearly with shear

Logistic regression modeling to assess groundwater vulnerability to contamination in Hawaii, USA.

PubMed

Mair, Alan; El-Kadi, Aly I

2013-10-01

Capture zone analysis combined with a subjective susceptibility index is currently used in Hawaii to assess vulnerability to contamination of drinking water sources derived from groundwater. In this study, we developed an alternative objective approach that combines well capture zones with multiple-variable logistic regression (LR) modeling and applied it to the highly-utilized Pearl Harbor and Honolulu aquifers on the island of Oahu, Hawaii. Input for the LR models utilized explanatory variables based on hydrogeology, land use, and well geometry/location. A suite of 11 target contaminants detected in the region, including elevated nitrate (>1 mg/L), four chlorinated solvents, four agricultural fumigants, and two pesticides, was used to develop the models. We then tested the ability of the new approach to accurately separate groups of wells with low and high vulnerability, and the suitability of nitrate as an indicator of other types of contamination. Our results produced contaminant-specific LR models that accurately identified groups of wells with the lowest/highest reported detections and the lowest/highest nitrate concentrations. Current and former agricultural land uses were identified as significant explanatory variables for eight of the 11 target contaminants, while elevated nitrate was a significant variable for five contaminants. The utility of the combined approach is contingent on the availability of hydrologic and chemical monitoring data for calibrating groundwater and LR models. Application of the approach using a reference site with sufficient data could help identify key variables in areas with similar hydrogeology and land use but limited data. In addition, elevated nitrate may also be a suitable indicator of groundwater contamination in areas with limited data. The objective LR modeling approach developed in this study is flexible enough to address a wide range of contaminants and represents a suitable addition to the current subjective approach

Logistic regression modeling to assess groundwater vulnerability to contamination in Hawaii, USA

NASA Astrophysics Data System (ADS)

Mair, Alan; El-Kadi, Aly I.

2013-10-01

Capture zone analysis combined with a subjective susceptibility index is currently used in Hawaii to assess vulnerability to contamination of drinking water sources derived from groundwater. In this study, we developed an alternative objective approach that combines well capture zones with multiple-variable logistic regression (LR) modeling and applied it to the highly-utilized Pearl Harbor and Honolulu aquifers on the island of Oahu, Hawaii. Input for the LR models utilized explanatory variables based on hydrogeology, land use, and well geometry/location. A suite of 11 target contaminants detected in the region, including elevated nitrate (> 1 mg/L), four chlorinated solvents, four agricultural fumigants, and two pesticides, was used to develop the models. We then tested the ability of the new approach to accurately separate groups of wells with low and high vulnerability, and the suitability of nitrate as an indicator of other types of contamination. Our results produced contaminant-specific LR models that accurately identified groups of wells with the lowest/highest reported detections and the lowest/highest nitrate concentrations. Current and former agricultural land uses were identified as significant explanatory variables for eight of the 11 target contaminants, while elevated nitrate was a significant variable for five contaminants. The utility of the combined approach is contingent on the availability of hydrologic and chemical monitoring data for calibrating groundwater and LR models. Application of the approach using a reference site with sufficient data could help identify key variables in areas with similar hydrogeology and land use but limited data. In addition, elevated nitrate may also be a suitable indicator of groundwater contamination in areas with limited data. The objective LR modeling approach developed in this study is flexible enough to address a wide range of contaminants and represents a suitable addition to the current subjective approach.

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.

Reducing aquatic hazards of industrial chemicals: probabilistic assessment of sustainable molecular design guidelines.

PubMed

Connors, Kristin A; Voutchkova-Kostal, Adelina M; Kostal, Jakub; Anastas, Paul; Zimmerman, Julie B; Brooks, Bryan W

2014-08-01

Basic toxicological information is lacking for the majority of industrial chemicals. In addition to increasing empirical toxicity data through additional testing, prospective computational approaches to drug development aim to serve as a rational basis for the design of chemicals with reduced toxicity. Recent work has resulted in the derivation of a "rule of 2," wherein chemicals with an octanol-water partition coefficient (log P) less than 2 and a difference between the lowest unoccupied molecular orbital and the highest occupied molecular orbital (ΔE) greater than 9 (log P<2 and ΔE >9 eV) are predicted to be 4 to 5 times less likely to elicit acute or chronic toxicity to model aquatic organisms. The present study examines potential reduction of aquatic toxicity hazards from industrial chemicals if these 2 molecular design guidelines were employed. Probabilistic hazard assessment approaches were used to model the likelihood of encountering industrial chemicals exceeding toxicological categories of concern both with and without the rule of 2. Modeling predicted that utilization of these molecular design guidelines for log P and ΔE would appreciably decrease the number of chemicals that would be designated to be of "high" and "very high" concern for acute and chronic toxicity to standard model aquatic organisms and end points as defined by the US Environmental Protection Agency. For example, 14.5% of chemicals were categorized as having high and very high acute toxicity to the fathead minnow model, whereas only 3.3% of chemicals conforming to the design guidelines were predicted to be in these categories. Considerations of specific chemical classes (e.g., aldehydes), chemical attributes (e.g., ionization), and adverse outcome pathways in representative species (e.g., receptor-mediated responses) could be used to derive future property guidelines for broader classes of contaminants. © 2014 SETAC.

Can in vitro assays account for interactions between inorganic co-contaminants observed during in vivo relative bioavailability assessment?

PubMed

Ollson, Cameron J; Smith, Euan; Juhasz, Albert L

2018-02-01

In vitro assays act as surrogate measurements of relative bioavailability (RBA) for inorganic contaminants. The values derived from these assays are routinely used to refine human health risk assessments (HHRA). Extensive in vitro research has been performed on three major inorganic contaminants; As, Cd and Pb. However, the majority of these studies have evaluated the contaminants individually, even in cases when they are found as co-contaminants. Recently, in vivo studies (animal model) have determined that when the three aforementioned contaminants are present in the same soil matrix, they have the ability to influence each other's individual bioavailability. Since in vitro assays are used to inform HHRA, this study investigated whether bioaccessibility methods including the Solubility/Bioavailability Research Consortium (SBRC) assay, and physiologically based extraction test (PBET), have the ability to detect interactions between As, Cd and Pb. Using a similar dosing methodology to recently published in vivo studies, spiked aged (12 years) soil was assessed by evaluating contaminant bioaccessibility individually, in addition to tertiary combinations. In two spiked aged soils (grey and brown chromosols), there was no influence on contaminant bioaccessibility when As, Cd and Pb we present as co-contaminants. However, in a red ferrosol, the presence of As and Pb significantly decreased (p < 0.05) the bioaccessibility of Cd when assessed using gastric and intestinal phases of the SBRC assay and the PBET. Conceivable, differences in key physico-chemical properties (TOC, Fe, Al, P) between the study soils influenced contaminant interactions and bioaccessibility outcomes. Although bioaccessibility methods may not account for interactions between elements as demonstrated in in vivo models, in vitro assessment provides a conservative prediction of contaminant RBA under co-contaminant scenarios. Copyright © 2017 Elsevier Ltd. All rights reserved.

IDENTIFYING THE SIGNATURE OF THE NATURAL ATTENUATION IN THE MICROBIAL ECOLOGY OF HYDROCARBON CONTAMINATED GROUNDWATER USING MOLECULAR METHODS AND &LDQUO;BUG TRAPS&RDQUO;

EPA Science Inventory

These related projects have combined biological molecular methods and a novel passive sampling system (bio-trap) to produce a technology that will allow the active component of any contaminated groundwater microbial community to be investigated. Conventional sampling methods c...

Assessment of Environmental Contamination with Pathogenic Bacteria at a Hospital Laundry Facility.

PubMed

Michael, Karen E; No, David; Daniell, William E; Seixas, Noah S; Roberts, Marilyn C

2017-11-10

Little is known about exposure to pathogenic bacteria among industrial laundry workers who work with soiled clinical linen. To study worker exposures, an assessment of surface contamination was performed at an industrial laundry facility serving hospitals in Seattle, WA, USA. Surface swab samples (n = 240) from the environment were collected during four site visits at 3-month intervals. These samples were cultured for Clostridium difficile, methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-resistant enterococci (VRE). Voluntary participation of 23 employees consisted of nasal swabs for detection of MRSA, observations during work, and questionnaires. Contamination with all three pathogens was observed in both dirty (laundry handling prior to washing) and clean areas (subsequent to washing). The dirty area had higher odds of overall contamination (≥1 pathogen) than the clean area (odds ratio, OR = 18.0, 95% confidence interval 8.9-36.5, P < 0.001). The odds of contamination were high for each individual pathogen: C. difficile, OR = 15.5; MRSA, OR = 14.8; and VRE, OR = 12.6 (each, P < 0.001). The highest odds of finding surface contamination occurred in the primary and secondary sort areas where soiled linens were manually sorted by employees (OR = 63.0, P < 0.001). The study substantiates that the laundry facility environment can become contaminated by soiled linens. Workers who handle soiled linen may have a higher risk of exposure to C. difficile, MRSA, and VRE than those who handle clean linens. Improved protocols for prevention and reduction of environmental contamination were implemented because of this study. © The Author 2017. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

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.

Metal uptake by homegrown vegetables – The relative importance in human health risk assessments at contaminated sites

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

Augustsson, Anna L.M., E-mail: anna.augustsson@lnu.se; Uddh-Söderberg, Terese E.; Hogmalm, K. Johan

Risk assessments of contaminated land often involve the use of generic bioconcentration factors (BCFs), which express contaminant concentrations in edible plant parts as a function of the concentration in soil, in order to assess the risks associated with consumption of homegrown vegetables. This study aimed to quantify variability in BCFs and evaluate the implications of this variability for human exposure assessments, focusing on cadmium (Cd) and lead (Pb) in lettuce and potatoes sampled around 22 contaminated glassworks sites. In addition, risks associated with measured Cd and Pb concentrations in soil and vegetable samples were characterized and a probabilistic exposure assessmentmore » was conducted to estimate the likelihood of local residents exceeding tolerable daily intakes. The results show that concentrations in vegetables were only moderately elevated despite high concentrations in soil, and most samples complied with applicable foodstuff legislation. Still, the daily intake of Cd (but not Pb) was assessed to exceed toxicological thresholds for about a fifth of the study population. Bioconcentration factors were found to vary more than indicated by previous studies, but decreasing BCFs with increasing metal concentrations in the soil can explain why the calculated exposure is only moderately affected by the choice of BCF value when generic soil guideline values are exceeded and the risk may be unacceptable. - Highlights: • Uptake of Cd and Pb by lettuce and potatoes increased with soil contamination. • Consumption of homegrown vegetables may lead to a daily Cd intake above TDIs. • The variability in the calculated BCFs is high when compared to previous studies. • Exposure assessments are most sensitive to the choice of BCFs at low contamination.« less

Development and Testing of Molecular Adsorber Coatings

NASA Technical Reports Server (NTRS)

Abraham, Nithin; Hasegawa, Mark; Straka, Sharon

2012-01-01

The effect of on-orbit molecular contamination has the potential to degrade the performance of spaceflight hardware and diminish the lifetime of the spacecraft. For example, sensitive surfaces, such as optical surfaces, electronics, detectors, and thermal control surfaces, are vulnerable to the damaging effects of contamination from outgassed materials. The current solution to protect these surfaces is through the use of zeolite coated ceramic adsorber pucks. However, these pucks and its additional complex mounting hardware requirements result in several disadvantages, such as size, weight, and cost related concerns, that impact the spacecraft design and the integration and test schedule. As a result, a new innovative molecular adsorber coating was developed as a sprayable alternative to mitigate the risk of on-orbit molecular contamination. In this study, the formulation for molecular adsorber coatings was optimized using various binders, pigment treatment methods, binder to pigment ratios, thicknesses, and spray application techniques. The formulations that passed coating adhesion and vacuum thermal cycling tests were further tested for its adsorptive capacity. Accelerated molecular capacitance tests were performed in an innovatively designed multi-unit system containing idealized contaminant sources. This novel system significantly increased the productivity of the testing phase for the various formulations that were developed. Work performed during the development and testing phases has demonstrated successful application of molecular adsorber coatings onto metallic substrates, as well as, very promising results for the adhesion performance and the molecular capacitance of the coating. Continued testing will assist in the qualification of molecular adsorber coatings for use on future contamination sensitive spaceflight missions.

Contamination control engineering design guidelines for the aerospace community

NASA Technical Reports Server (NTRS)

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

1996-01-01

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

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.

Human health risk assessment in restoring safe and productive use of abandoned contaminated sites.

PubMed

Wcisło, Eleonora; Bronder, Joachim; Bubak, Anicenta; Rodríguez-Valdés, Eduardo; Gallego, José Luis R

2016-09-01

In Europe soil contamination has been recognized as a serious problem. The needs to remediate contaminated sites are not questionable, although the remediation actions are often hindered by their very high financial costs. On the other hand, the abandoned contaminated sites may have the potential for redevelopment and creating conditions appropriate for their productive reuse bringing social, economic and environmental benefits. The main concern associated with the contaminated sites is their potential adverse health impact. Therefore, in the process of contaminated site redevelopment the risk assessment and the subsequent risk management decisions will play a crucial role. The main objective of this study was to illustrate the role of the human health risk assessment (HRA) in supporting site remediation and reuse decisions. To exemplify the significance of the HRA process in this field the Nitrastur site, located in Asturias, Spain was used. Risks resulting from soil contamination with arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), mercury (Hg), zinc (Zn) and lead (Pb) were assessed under three potential future land use patterns: industrial, residential and recreational. The results of the study indicated that soil at the Nitrastur site might pose non-cancer and cancer risks to potential future receptors - industrial workers, residents and recreational users. Arsenic and lead are the main substances responsible for the health risk and the primary drivers of remedial decisions at the site. The highest total cancer risks were observed under the residential scenario, followed in descending order by the recreational and industrial ones. The remedial maps illustrate in which areas remediation activities are required, depending on a given land use pattern. The obtained results may be used to develop, analyse, compare and select the remedial options within the intended land use pattern. They may also be used to support the decisions concerning the

A Review of the Field on Children's Exposure to Environmental Contaminants: A Risk Assessment Approach.

PubMed

Ferguson, Alesia; Penney, Rosalind; Solo-Gabriele, Helena

2017-03-04

Background : Children must be recognized as a sensitive population based on having biological systems and organs in various stages of development. The processes of absorption, distribution, metabolism and elimination of environmental contaminants within a child's body are considered less advanced than those of adults, making them more susceptible to disease outcomes following even small doses. Children's unique activities of crawling and practicing increased hand-to-mouth ingestion also make them vulnerable to greater exposures by certain contaminants within specific environments. Approach : There is a need to review the field of children's environmental exposures in order to understand trends and identify gaps in research, which may lead to better protection of this vulnerable and sensitive population. Therefore, explored here are previously published contemporary works in the broad area of children's environmental exposures and potential impact on health from around the world. A discussion of children's exposure to environmental contaminants is best organized under the last four steps of a risk assessment approach: hazard identification, dose-response assessment, exposure assessment (including children's activity patterns) and risk characterization. We first consider the many exposure hazards that exist in the indoor and outdoor environments, and emerging contaminants of concern that may help guide the risk assessment process in identifying focus areas for children. A section on special diseases of concern is also included. Conclusions : The field of children's exposures to environmental contaminants is broad. Although there are some well-studied areas offering much insight into children exposures, research is still needed to further our understanding of exposures to newer compounds, growing disease trends and the role of gene-environment interactions that modify adverse health outcomes. It is clear that behaviors of adults and children play a role in reducing or

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.

Effects-based spatial assessment of contaminated estuarine sediments from Bear Creek, Baltimore Harbor, MD, USA.

PubMed

Hartzell, Sharon E; Unger, Michael A; McGee, Beth L; Wilson, Sacoby M; Yonkos, Lance T

2017-10-01

Estuarine sediments in regions with prolonged histories of industrial activity are often laden to significant depths with complex contaminant mixtures, including trace metals and persistent organic pollutants. Given the complexity of assessing risks from multi-contaminant exposures, the direct measurement of impacts to biological receptors is central to characterizing contaminated sediment sites. Though biological consequences are less commonly assessed at depth, laboratory-based toxicity testing of subsurface sediments can be used to delineate the scope of contamination at impacted sites. The extent and depth of sediment toxicity in Bear Creek, near Baltimore, Maryland, USA, was delineated using 10-day acute toxicity tests with the estuarine amphipod Leptocheirus plumulosus, and chemical analysis of trace metals and persistent organic pollutants. A gradient of toxicity was demonstrated in surface sediments with 21 of 22 tested sites differing significantly from controls. Effects were most pronounced (100% lethality) at sites proximate to a historic industrial complex. Sediments from eight of nine core samples to depths of 80 cm were particularly impacted (i.e., caused significant lethality to L. plumulosus) even in locations overlain with relatively non-toxic surface sediments, supporting a conclusion that toxicity observed at the surface (top 2 cm) does not adequately predict toxicity at depth. In seven of nine sites, toxicity of surface sediments differed from toxicity at levels beneath by 28 to 69%, in five instances underestimating toxicity (28 to 69%), and in two instances overestimating toxicity (44 to 56%). Multiple contaminants exceeded sediment quality guidelines and correlated positively with toxic responses within surface sediments (e.g., chromium, nickel, polycyclic aromatic hydrocarbon (PAH), total petroleum hydrocarbon). Use of an antibody-based PAH biosensor revealed that porewater PAH concentrations also increased with depth at most sites. This

An evaluation of contaminated estuarine sites using sediment quality guidelines and ecological assessment methodologies.

PubMed

Fulton, M; Key, P; Wirth, E; Leight, A K; Daugomah, J; Bearden, D; Sivertsen, S; Scott, G

2006-10-01

Toxic contaminants may enter estuarine ecosystems through a variety of pathways. When sediment contaminant levels become sufficiently high, they may impact resident biota. One approach to predict sediment-associated toxicity in estuarine ecosystems involves the use of sediment quality guidelines (ERMs, ERLs) and site-specific contaminant chemistry while a second approach utilizes site-specific ecological sampling to assess impacts at the population or community level. The goal of this study was to utilize an integrated approach including chemical contaminant analysis, sediment quality guidelines and grass shrimp population monitoring to evaluate the impact of contaminants from industrial sources. Three impacted sites and one reference site were selected for study. Grass shrimp populations were sampled using a push-netting approach. Sediment samples were collected at each site and analyzed for metals, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and pesticides. Contaminant levels were then compared to sediment quality guidelines. In general, grass shrimp population densities at the sites decreased as the ERM quotients increased. Grass shrimp densities were significantly reduced at the impacted site that had an ERM exceedance for chromium and the highest Mean ERM quotient. Regression analysis indicated that sediment chromium concentrations were negatively correlated with grass shrimp density. Grass shrimp size was reduced at two sites with intermediate levels of contamination. These findings support the use of both sediment quality guidelines and site-specific population monitoring to evaluate the impacts of sediment-associated contaminants in estuarine systems.

Preliminary hydrogeologic assessment of a ground-water contamination area in Wolcott, Connecticut

USGS Publications Warehouse

Stone, J.R.; Casey, G.D.; Mondazzi, R.A.; Frick, T.W.

1997-01-01

Contamination of ground water by volatile organic compounds and inorganic constituents has been identified at a number of industrial sites in the Town of Wolcott, Connecticut. Contamination is also present at a municipal landfill in the City of Waterbury that is upgradient from the industrial sites in the local ground-water-flow system. The study area, which lies in the Western Highlands of Connecticut, is in the Mad River Valley, a tributary to the Naugatuck River. Geohydrologic units (aquifer materials) include unconsolidated glacial sediments (surficial materials) and fractured crystalline (metamorphic) bedrock. Surficial materials include glacial till, coarse-grained andfine-grained glacial stratified deposits, and postglacial floodplain alluvium and swamp deposits. The ground-water-flow system in the surficial aquifer is complex because the hydraulic properties of the surficial materials are highly variable. In the bedrock aquifer, ground water moves exclusively through fractures. Hydrologic characteristics of the crystalline bedrock-degree of confinement, hydraulic conductivity, storativity, and porosity-are poorly defined in the study area. Further study is needed to adequately assess ground-water flow and contaminant migration under current or past hydrologic conditions. All known water-supply wells in the study area obtain water from the bedrock aquifer. Twenty households in a hillside residential area on Tosun Road currently obtain drinking water from private wells tapping the bedrock aquifer. The extent of contamination in the bedrock aquifer and the potential for future contamination from known sources of contamination in the surficial aquifer is of concern to regulatory agencies. Previous investigations have identified ground-water contamination by volatile organic compounds at the Nutmeg Valley Road site area. Contamination has been associated with on-site disposal of heavy metals, chlorinated and non-chlorinated volatile organic compounds, and

Using bioavailability to assess contaminated sediment risk: Passive sampling and Pore Water Remedial Guidelines (PWRGs)

EPA Science Inventory

Hosted by the Contaminated Sediment Forum, this half-day course will introduce the RPM to the use of passive samplers to assess bioavailability and in ecological risk assessment. Passive sampling devices (PSD) are a technology with growing acceptance for measuring porewater conce...

The Penobscot River and environmental contaminants: Assessment of tribal exposure through sustenance lifeways

USGS Publications Warehouse

Marshall, Valerie; Kusnierz, Daniel; Hillger, Robert; Ferrario, Joseph; Hughes, Thomas; Diliberto, Janet; Orazio, Carl E.; Dudley, Robert W.; Byrne, Christian; Sugatt, Richard; Warren, Sarah; DeMarini, David; Elskus, Adria; Stodola, Steve; Mierzykowski, Steve; Pugh, Katie; Culbertson, Charles W.

2015-01-01

EPA in collaboration with the Penobscot Indian Nation, U.S. Geological Survey (USGS), Agency for Toxic Substances and Disease Registry (ATSDR), and the U.S. Fish and Wildlife Service (USF&WS) collectively embarked on a four year research study to evaluate the environmental health of the riverine system by targeting specific cultural practices and using traditional science to conduct a preliminary contaminant screening of the flora and fauna of the Penobscot River ecosystem. This study was designed as a preliminary screening to determine if contaminant concentrations in fish, eel, snapping turtle, wood ducks, and plants in Regions of the Penobscot River relevant to where PIN tribal members hunt, fish and gather plants were high enough to be a health concern. This study was not designed to be a statistically validated assessment of contaminant differences among study sites or among species. The traditional methodology for health risk assessment used by the U. S. Environmental Protection Agency (EPA) is based on the use of exposure assumptions (e.g. exposure duration, food ingestion rate, body weight, etc.) that represent the entire American population, either as a central tendency exposure (e.g. average, median) or as a reasonable maximum exposure (e.g. 95% upper confidence limit). Unfortunately, EPA lacked exposure information for assessing health risks for New England regional tribes sustaining a tribal subsistence way of life. As a riverine tribe, the Penobscot culture and traditions are inextricably tied to the Penobscot River watershed. It is through hunting, fishing, trapping, gathering and making baskets, pottery, moccasins, birch-bark canoes and other traditional practices that the Penobscot culture and people are sustained. The Penobscot River receives a variety of pollutant discharges leaving the Penobscot Indian Nation (PIN) questioning the ecological health and water quality of the river and how this may affect the practices that sustain their way of life

Acute toxicity assessment of explosive-contaminated soil extracting solution by luminescent bacteria assays.

PubMed

Xu, Wenjie; Jiang, Zhenming; Zhao, Quanlin; Zhang, Zhenzhong; Su, Hongping; Gao, Xuewen; Ye, Zhengfang

2016-11-01

Explosive-contaminated soil is harmful to people's health and the local ecosystem. The acute toxicity of its extracting solution was tested by bacterial luminescence assay using three kinds of luminescent bacteria to characterize the toxicity of the soil. An orthogonal test L 16 (4 5 ) was designed to optimize the soil extracting conditions. The optimum extracting conditions were obtained when the ultrasonic extraction time, ultrasonic extraction temperature, and the extraction repeat times were 6 h, 40 °C, and three, respectively. Fourier transform infrared spectroscopy (FTIR) results showed that the main components of the contaminated soil's extracting solution were 2,4-dinitrotoluene-3-sulfonate (2,4-DNT-3-SO 3 - ); 2,4-dinitrotoluene-5-sulfonate (2,4-DNT-5-SO 3 - ); and 2,6-dinitrotoluene (2,6-DNT). Compared with Photobacterium phosphoreum and Vibrio fischeri, Vibrio qinghaiensis sp. Nov. is more suitable for assessing the soil extracting solution's acute toxicity. Soil washing can remove most of the contaminants toxic to luminescent bacterium Vibrio qinghaiensis sp. Nov., suggesting that it may be a potential effective remediation method for explosive-contaminated soil.

Utility of Microbial Source-Tracking Markers for Assessing Fecal Contamination in the Portage River Watershed, Northwestern Ohio, 2008

USGS Publications Warehouse

Kephart, Christopher M.; Bushon, Rebecca N.

2010-01-01

An influx of concentrated animal feeding operations in northwest Ohio has prompted local agencies to examine the effects of these industrial farms on water quality in the upper Portage River watershed. The utility of microbial source-tracking (MST) tools as a means of characterizing sources of fecal contamination in the watershed was evaluated. From 2007 to 2008, scientists with the U.S. Geological Survey, Bowling Green State University, and the Wood County Health Department collected and analyzed 17 environmental samples and 13 fecal source samples for Bacteroides-based host-associated DNA markers. At many of the environmental sites tested, MST marker results corroborated the presumptive fecal contamination sources. Results from this demonstration study support the utility of using MST with host-specific molecular markers to characterize the sources of fecal contamination in the Portage River watershed.

Assessment of microbial contamination of radiographic equipment and materials during intraoral imaging procedures.

PubMed

Pinheiro, S L; Martoni, S C; Ogera, R R

2012-05-01

Aim of the present study was to assess microbial contamination of radiology procedures. Patients who needed radiographic exams were selected and the bisecting technique was used: G1 - (control): absence of plastic barrier and overgloving or disinfectant solutions; G2 - alcohol spraying; G3 - protection of the film with a plastic barrier and alcohol spray; G4 - protection of film with plastic barrier, use of overgloving and alcohol spray. The following regions were assessed: trigger switch, X-ray tube, sleeve of the portable dark chamber, water, developer and fixer. The areas for microbiological sample collection were standardized with a label cut internally so that the hollow area was 5 cm long and 2 cm wide. One mL of the developer, water and fixer were also collected before and after developing the films. The samples were incubated under anaerobiosis and aerobiosis. The results were submitted to the Cochran's Q and Mann-Whitney tests. The sleeve of the developing chamber showed greater anaerobic contamination followed by the X-ray tube and only the use of alcohol associated with mechanical barriers was efficient to control this microbiota. The trigger showed higher aerobic microbial contamination and the use of alcohol or alcohol associated with mechanical barriers was efficient to control this microbiota. The developing solutions presented no significant growth of anaerobic and aerobic bacteria. The characteristic of an aerobic or anaerobic microbial strain influences microbial contamination while radiographic projections are being taken and the use of alcohol associated with a plastic barrier and overgloving is indicated to reduce this microbiota.

Challenges in assessing the health risks of consuming vegetables in metal-contaminated environments.

PubMed

Augustsson, Anna; Uddh-Söderberg, Terese; Filipsson, Monika; Helmfrid, Ingela; Berglund, Marika; Karlsson, Helen; Hogmalm, Johan; Karlsson, Andreas; Alriksson, Stina

2018-04-01

A great deal of research has been devoted to the characterization of metal exposure due to the consumption of vegetables from urban or industrialized areas. It may seem comforting that concentrations in crops, as well as estimated exposure levels, are often found to be below permissible limits. However, we show that even a moderate increase in metal accumulation in crops may result in a significant increase in exposure. We also highlight the importance of assessing exposure levels in relation to a regional baseline. We have analyzed metal (Pb, Cd, As) concentrations in nearly 700 samples from 23 different vegetables, fruits, berries and mushrooms, collected near 21 highly contaminated industrial sites and from reference sites. Metal concentrations generally complied with permissible levels in commercial food and only Pb showed overall higher concentrations around the contaminated sites. Nevertheless, probabilistic exposure assessments revealed that the exposure to all three metals was significantly higher in the population residing around the contaminated sites, for both low-, median- and high consumers. The exposure was about twice as high for Pb and Cd, and four to six times as high for As. Since vegetable consumption alone did not result in exposure above tolerable intakes, it would have been easy to conclude that there is no risk associated with consuming vegetables grown near the contaminated sites. However, when the increase in exposure is quantified, its potential significance is harder to dismiss - especially when considering that exposure via other routes may be elevated in a similar way. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Molecular environmental geochemistry

NASA Astrophysics Data System (ADS)

O'Day, Peggy A.

1999-05-01

The chemistry, mobility, and bioavailability of contaminant species in the natural environment are controlled by reactions that occur in and among solid, aqueous, and gas phases. These reactions are varied and complex, involving changes in chemical form and mass transfer among inorganic, organic, and biochemical species. The field of molecular environmental geochemistry seeks to apply spectroscopic and microscopic probes to the mechanistic understanding of environmentally relevant chemical processes, particularly those involving contaminants and Earth materials. In general, empirical geochemical models have been shown to lack uniqueness and adequate predictive capability, even in relatively simple systems. Molecular geochemical tools, when coupled with macroscopic measurements, can provide the level of chemical detail required for the credible extrapolation of contaminant reactivity and bioavailability over ranges of temperature, pressure, and composition. This review focuses on recent advances in the understanding of molecular chemistry and reaction mechanisms at mineral surfaces and mineral-fluid interfaces spurred by the application of new spectroscopies and microscopies. These methods, such as synchrotron X-ray absorption and scattering techniques, vibrational and resonance spectroscopies, and scanning probe microscopies, provide direct chemical information that can elucidate molecular mechanisms, including element speciation, ligand coordination and oxidation state, structural arrangement and crystallinity on different scales, and physical morphology and topography of surfaces. Nonvacuum techniques that allow examination of reactions in situ (i.e., with water or fluids present) and in real time provide direct links between molecular structure and reactivity and measurements of kinetic rates or thermodynamic properties. Applications of these diverse probes to laboratory model systems have provided fundamental insight into inorganic and organic reactions at

Individual and molecular level effects of produced water contaminants on nauplii and adult females of Calanus finmarchicus.

PubMed

Jensen, Louise Kiel; Halvorsen, Elisabeth; Song, You; Hallanger, Ingeborg G; Hansen, Elisabeth Lindbo; Brooks, Steven J; Hansen, Bjørn Henrik; Tollefsen, Knut Erik

2016-01-01

In the Barents Sea region new petroleum fields are discovered yearly and extraction of petroleum products is expected to increase in the upcoming years. Despite enhanced technology and stricter governmental legislation, establishment of the petroleum industry in the Barents Sea may potentially introduce a new source of contamination to the area, as some discharges of produced water will be allowed. Whether the presence of produced water poses a risk to the Arctic marine life remains to be investigated. The aim of this study was to examine effects of exposure to several compounds found in produced water-a mixture of selected organic compounds (APW), radium-226 ((226)Ra), barium (Ba), and a scale inhibitor-on the copepod species Calanus finmarchicus. Experiments were performed using exposure concentrations at realistic levels based on those detected in the vicinity of known discharge points. The influence of lethal and sublethal effects on early life stages was determined and significantly lower survival in the APW exposure groups was found. In the Ba treatment the life stage development did not proceed to the same advanced stages as observed in the control (filtered sea water). The scale inhibitor and (226)Ra treatments showed no significant difference from control. In addition, adult females were exposed to APW, (226)Ra, and a mixture of the two. Both individual-level effects (egg production and feeding) and molecular-level effects (gene expression) were assessed. On the individual level endpoints, only treatments including APW produced an effect compared to control. However, on the molecular level the possibility that also (226)Ra induced toxicologically relevant effects cannot be ruled out.

Integrated methodology for assessing the HCH groundwater pollution at the multi-source contaminated mega-site Bitterfeld/Wolfen.

PubMed

Wycisk, Peter; Stollberg, Reiner; Neumann, Christian; Gossel, Wolfgang; Weiss, Holger; Weber, Roland

2013-04-01

A large-scale groundwater contamination characterises the Pleistocene groundwater system of the former industrial and abandoned mining region Bitterfeld/Wolfen, Eastern Germany. For more than a century, local chemical production and extensive lignite mining caused a complex contaminant release from local production areas and related dump sites. Today, organic pollutants (mainly organochlorines) are present in all compartments of the environment at high concentration levels. An integrated methodology for characterising the current situation of pollution as well as the future fate development of hazardous substances is highly required to decide on further management and remediation strategies. Data analyses have been performed on regional groundwater monitoring data from about 10 years, containing approximately 3,500 samples, and up to 180 individual organic parameters from almost 250 observation wells. Run-off measurements as well as water samples were taken biweekly from local creeks during a period of 18 months. A kriging interpolation procedure was applied on groundwater analytics to generate continuous distribution patterns of the nodal contaminant samples. High-resolution geological 3-D modelling serves as a database for a regional 3-D groundwater flow model. Simulation results support the future fate assessment of contaminants. A first conceptual model of the contamination has been developed to characterise the contamination in regional surface waters and groundwater. A reliable explanation of the variant hexachlorocyclohexane (HCH) occurrence within the two local aquifer systems has been derived from the regionalised distribution patterns. Simulation results from groundwater flow modelling provide a better understanding of the future pollutant migration paths and support the overall site characterisation. The presented case study indicates that an integrated assessment of large-scale groundwater contaminations often needs more data than only from local

Molecular Environmental Science: An Assessment of Research Accomplishments, Available Synchrotron Radiation Facilities, and Needs

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

Brown, G

2004-02-05

Synchrotron-based techniques are fundamental to research in ''Molecular Environmental Science'' (MES), an emerging field that involves molecular-level studies of chemical and biological processes affecting the speciation, properties, and behavior of contaminants, pollutants, and nutrients in the ecosphere. These techniques enable the study of aqueous solute complexes, poorly crystalline materials, solid-liquid interfaces, mineral-aqueous solution interactions, microbial biofilm-heavy metal interactions, heavy metal-plant interactions, complex material microstructures, and nanomaterials, all of which are important components or processes in the environment. Basic understanding of environmental materials and processes at the molecular scale is essential for risk assessment and management, and reduction of environmental pollutantsmore » at field, landscape, and global scales. One of the main purposes of this report is to illustrate the role of synchrotron radiation (SR)-based studies in environmental science and related fields and their impact on environmental problems of importance to society. A major driving force for MES research is the need to characterize, treat, and/or dispose of vast quantities of contaminated materials, including groundwater, sediments, and soils, and to process wastes, at an estimated cost exceeding 150 billion dollars through 2070. A major component of this problem derives from high-level nuclear waste. Other significant components come from mining and industrial wastes, atmospheric pollutants derived from fossil fuel consumption, agricultural pesticides and fertilizers, and the pollution problems associated with animal waste run-off, all of which have major impacts on human health and welfare. Addressing these problems requires the development of new characterization and processing technologies--efforts that require information on the chemical speciation of heavy metals, radionuclides, and xenobiotic organic compounds and their reactions

HOLISTIC APPROACH FOR ASSESSING THE PRESENCE AND POTENTIAL IMPACTS OF WATERBORNE ENVIRONMENTAL CONTAMINANTS

EPA Science Inventory

As an integral part of our continuing research in environmental quality assessment approaches, we have developed a variety of passive integrative sampling devices widely applicable for use in defining the presence and potential impacts of a broad array of contaminants. The semipe...

A holistic passive integrative sampling approach for assessing the presence and potential impacts of waterborne environmental contaminants

USGS Publications Warehouse

Petty, J.D.; Huckins, J.N.; Alvarez, D.A.; Brumbaugh, W. G.; Cranor, W.L.; Gale, R.W.; Rastall, A.C.; Jones-Lepp, T. L.; Leiker, T.J.; Rostad, C. E.; Furlong, E.T.

2004-01-01

As an integral part of our continuing research in environmental quality assessment approaches, we have developed a variety of passive integrative sampling devices widely applicable for use in defining the presence and potential impacts of a broad array of contaminants. The semipermeable membrane device has gained widespread use for sampling hydrophobic chemicals from water and air, the polar organic chemical integrative sampler is applicable for sequestering waterborne hydrophilic organic chemicals, the stabilized liquid membrane device is used to integratively sample waterborne ionic metals, and the passive integrative mercury sampler is applicable for sampling vapor phase or dissolved neutral mercury species. This suite of integrative samplers forms the basis for a new passive sampling approach for assessing the presence and potential toxicological significance of a broad spectrum of environmental contaminants. In a proof-of-concept study, three of our four passive integrative samplers were used to assess the presence of a wide variety of contaminants in the waters of a constructed wetland, and to determine the effectiveness of the constructed wetland in removing contaminants. The wetland is used for final polishing of secondary-treatment municipal wastewater and the effluent is used as a source of water for a state wildlife area. Numerous contaminants, including organochlorine pesticides, polycyclic aromatic hydrocarbons, organophosphate pesticides, and pharmaceutical chemicals (e.g., ibuprofen, oxindole, etc.) were detected in the wastewater. Herein we summarize the results of the analysis of the field-deployed samplers and demonstrate the utility of this holistic approach.

Metal uptake by homegrown vegetables - the relative importance in human health risk assessments at contaminated sites.

PubMed

Augustsson, Anna L M; Uddh-Söderberg, Terese E; Hogmalm, K Johan; Filipsson, Monika E M

2015-04-01

Risk assessments of contaminated land often involve the use of generic bioconcentration factors (BCFs), which express contaminant concentrations in edible plant parts as a function of the concentration in soil, in order to assess the risks associated with consumption of homegrown vegetables. This study aimed to quantify variability in BCFs and evaluate the implications of this variability for human exposure assessments, focusing on cadmium (Cd) and lead (Pb) in lettuce and potatoes sampled around 22 contaminated glassworks sites. In addition, risks associated with measured Cd and Pb concentrations in soil and vegetable samples were characterized and a probabilistic exposure assessment was conducted to estimate the likelihood of local residents exceeding tolerable daily intakes. The results show that concentrations in vegetables were only moderately elevated despite high concentrations in soil, and most samples complied with applicable foodstuff legislation. Still, the daily intake of Cd (but not Pb) was assessed to exceed toxicological thresholds for about a fifth of the study population. Bioconcentration factors were found to vary more than indicated by previous studies, but decreasing BCFs with increasing metal concentrations in the soil can explain why the calculated exposure is only moderately affected by the choice of BCF value when generic soil guideline values are exceeded and the risk may be unacceptable. Copyright © 2015 Elsevier Inc. All rights reserved.

Development and application of a novel method for regional assessment of groundwater contamination risk in the Songhua River Basin.

PubMed

Nixdorf, Erik; Sun, Yuanyuan; Lin, Mao; Kolditz, Olaf

2017-12-15

The main objective of this study is to quantify the groundwater contamination risk of Songhua River Basin by applying a novel approach of integrating public datasets, web services and numerical modelling techniques. To our knowledge, this study is the first to establish groundwater risk maps for the entire Songhua River Basin, one of the largest and most contamination-endangered river basins in China. Index-based groundwater risk maps were created with GIS tools at a spatial resolution of 30arc sec by combining the results of groundwater vulnerability and hazard assessment. Groundwater vulnerability was evaluated using the DRASTIC index method based on public datasets at the highest available resolution in combination with numerical groundwater modelling. As a novel approach to overcome data scarcity at large scales, a web mapping service based data query was applied to obtain an inventory for potential hazardous sites within the basin. The groundwater risk assessment demonstrated that <1% of Songhua River Basin is at high or very high contamination risk. These areas were mainly located in the vast plain areas with hotspots particularly in the Changchun metropolitan area. Moreover, groundwater levels and pollution point sources were found to play a significantly larger impact in assessing these areas than originally assumed by the index scheme. Moderate contamination risk was assigned to 27% of the aquifers, predominantly associated with less densely populated agricultural areas. However, the majority of aquifer area in the sparsely populated mountain ranges displayed low groundwater contamination risk. Sensitivity analysis demonstrated that this novel method is valid for regional assessments of groundwater contamination risk. Despite limitations in resolution and input data consistency, the obtained groundwater contamination risk maps will be beneficial for regional and local decision-making processes with regard to groundwater protection measures, particularly if

Assessment of Molecular Construction in Undergraduate Biochemistry

ERIC Educational Resources Information Center

Booth, Deborah; Bateman, Robert C., Jr.; Sirochman, Rudy; Richardson, David C.; Richardson, Jane S.; Weiner, Steven W.; Farwell, Mary; Putnam-Evans, Cindy

2005-01-01

White and group used a two question, open-ended tests to separately evaluate students' learning of specific biochemical concepts in the general biology lecture and laboratory, in the first performance assessment of molecular visualization in teaching biochemistry. Two studies were devoted to protein structure using globins followed by one…

Application of molecularly imprinted and non-imprinted polymers for removal of emerging contaminants in water and wastewater treatment: a review.

PubMed

Murray, Audrey; Ormeci, Banu

2012-11-01

Over the past decade, several studies have reported trace levels of endocrine disrupting compounds, pharmaceuticals, and personal care products in surface waters, drinking water, and wastewater effluents. There has also been an increased concern about the ecological and human health impact of these contaminants, and their removal from water and wastewater has become a priority. Traditional treatment processes are limited in their ability to remove emerging contaminants from water, and there is a need for new technologies that are effective and feasible. This paper presents a review on recent research results on molecularly imprinted (MIP) and non-imprinted (NIP) polymers and evaluates their potential as a treatment method for the removal of emerging contaminants from water and wastewater. It also discusses the relative benefits and limitations of using MIP or NIP for water and wastewater treatment. MIP, and in particular NIP, offer promising applications for wastewater treatment, but their toxicity and possible health effects should be carefully studied before they are considered for drinking water treatment. More research is also required to determine how best to incorporate MIP and NIP in treatment plants.

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.

Muddying the Waters: A New Area of Concern for Drinking Water Contamination in Cameroon

PubMed Central

Healy Profitós, Jessica M.; Mouhaman, Arabi; Lee, Seungjun; Garabed, Rebecca; Moritz, Mark; Piperata, Barbara; Tien, Joe; Bisesi, Michael; Lee, Jiyoung

2014-01-01

In urban Maroua, Cameroon, improved drinking water sources are available to a large majority of the population, yet this water is frequently distributed through informal distribution systems and stored in home containers (canaries), leaving it vulnerable to contamination. We assessed where contamination occurs within the distribution system, determined potential sources of environmental contamination, and investigated potential pathogens. Gastrointestinal health status (785 individuals) was collected via health surveys. Drinking water samples were collected from drinking water sources and canaries. Escherichia coli and total coliform levels were evaluated and molecular detection was performed to measure human-associated faecal marker, HF183; tetracycline-resistance gene, tetQ; Campylobacter spp.; and Staphylococcus aureus. Statistical analyses were performed to evaluate the relationship between microbial contamination and gastrointestinal illness. Canari samples had higher levels of contamination than source samples. HF183 and tetQ were detected in home and source samples. An inverse relationship was found between tetQ and E. coli. Presence of tetQ with lower E. coli levels increased the odds of reported diarrhoeal illness than E. coli levels alone. Further work is warranted to better assess the relationship between antimicrobial-resistant bacteria and other pathogens in micro-ecosystems within canaries and this relationship’s impact on drinking water quality. PMID:25464137

Muddying the waters: a new area of concern for drinking water contamination in Cameroon.

PubMed

Profitós, Jessica M Healy; Mouhaman, Arabi; Lee, Seungjun; Garabed, Rebecca; Moritz, Mark; Piperata, Barbara; Tien, Joe; Bisesi, Michael; Lee, Jiyoung

2014-11-28

In urban Maroua, Cameroon, improved drinking water sources are available to a large majority of the population, yet this water is frequently distributed through informal distribution systems and stored in home containers (canaries), leaving it vulnerable to contamination. We assessed where contamination occurs within the distribution system, determined potential sources of environmental contamination, and investigated potential pathogens. Gastrointestinal health status (785 individuals) was collected via health surveys. Drinking water samples were collected from drinking water sources and canaries. Escherichia coli and total coliform levels were evaluated and molecular detection was performed to measure human-associated faecal marker, HF183; tetracycline-resistance gene, tetQ; Campylobacter spp.; and Staphylococcus aureus. Statistical analyses were performed to evaluate the relationship between microbial contamination and gastrointestinal illness. Canari samples had higher levels of contamination than source samples. HF183 and tetQ were detected in home and source samples. An inverse relationship was found between tetQ and E. coli. Presence of tetQ with lower E. coli levels increased the odds of reported diarrhoeal illness than E. coli levels alone. Further work is warranted to better assess the relationship between antimicrobial-resistant bacteria and other pathogens in micro-ecosystems within canaries and this relationship's impact on drinking water quality.

Risk assessment of brine contamination to aquatic resources from energy development in glacial drift deposits: Williston Basin, USA

USGS Publications Warehouse

Preston, Todd M.; Chesley-Preston, Tara

2015-01-01

Our goal was to improve the Sheridan County assessment (SCA) and evaluate the use of this new Williston Basin assessment (WBA) across 31 counties mantled by glacial drift in the Williston Basin. To determine if the WBA model improved the SCA model, results from both assessments were compared to CI values from 37 surface and groundwater samples collected to evaluate the SCA. The WBA (R2 = 0.65) outperformed the SCA (R2 = 0.52) indicating improved model performance. Applicability across the Williston Basin was evaluated by comparing WBA results to CI values from 123 surface water samples collected from 97 sections. Based on the WBA, the majority (83.5%) of sections lacked an oil well and had minimal risk. Sections with one or more oil wells comprised low (8.4%), moderate (6.5%), or high (1.7%) risk areas. The percentage of contaminated water samples, percentage of sections with at least one contaminated sample, and the average CI value of contaminated samples increased from low to high risk indicating applicability across the Williston Basin. Furthermore, the WBA performed better compared to only the contaminated samples (R2 = 0.62) versus all samples (R2 = 0.38). This demonstrates that the WBA was successful at identifying sections, but not individual aquatic resources, with an increased risk of contamination; therefore, WBA results can prioritize future sampling within areas of increased risk.

Earthworm Comet Assay for Assessing the Risk of Weathered Petroleum Hydrocarbon Contaminated Soils: Need to Look Further than Target Contaminants.

PubMed

Ramadass, Kavitha; Palanisami, Thavamani; Smith, Euan; Mayilswami, Srinithi; Megharaj, Mallavarapu; Naidu, Ravi

2016-11-01

Earthworm toxicity assays contribute to ecological risk assessment and consequently standard toxicological endpoints, such as mortality and reproduction, are regularly estimated. These endpoints are not enough to better understand the mechanism of toxic pollutants. We employed an additional endpoint in the earthworm Eisenia andrei to estimate the pollutant-induced stress. In this study, comet assay was used as an additional endpoint to evaluate the genotoxicity of weathered hydrocarbon contaminated soils containing 520 to 1450 mg hydrocarbons kg -1 soil. Results showed that significantly higher DNA damage levels (two to sixfold higher) in earthworms exposed to hydrocarbon impacted soils. Interestingly, hydrocarbons levels in the tested soils were well below site-specific screening guideline values. In order to explore the reasons for observed toxicity, the contaminated soils were leached with rainwater and subjected to earthworm tests, including the comet assay, which showed no DNA damage. Soluble hydrocarbon fractions were not found originally in the soils and hence no hydrocarbons leached out during soil leaching. The soil leachate's Electrical Conductivity (EC) decreased from an average of 1665 ± 147 to 204 ± 20 µS cm -1 . Decreased EC is due to the loss of sodium, magnesium, calcium, and sulphate. The leachate experiment demonstrated that elevated salinity might cause the toxicity and not the weathered hydrocarbons. Soil leaching removed the toxicity, which is substantiated by the comet assay and soil leachate analysis data. The implication is that earthworm comet assay can be included in future eco (geno) toxicology studies to assess accurately the risk of contaminated soils.

Evaluation methods for assessing effectiveness of in situ remediation of soil and sediment contaminated with organic pollutants and heavy metals.

PubMed

Song, Biao; Zeng, Guangming; Gong, Jilai; Liang, Jie; Xu, Piao; Liu, Zhifeng; Zhang, Yi; Zhang, Chen; Cheng, Min; Liu, Yang; Ye, Shujing; Yi, Huan; Ren, Xiaoya

2017-08-01

Soil and sediment contamination has become a critical issue worldwide due to its great harm to the ecological environment and public health. In recent years, many remediation technologies including physical, chemical, biological, and combined methods have been proposed and adopted for the purpose of solving the problems of soil and sediment contamination. However, current research on evaluation methods for assessing these remediation technologies is scattered and lacks valid and integrated evaluation methods for assessing the remediation effectiveness. This paper provides a comprehensive review with an environmental perspective on the evaluation methods for assessing the effectiveness of in situ remediation of soil and sediment contaminated with organic pollutants and heavy metals. The review systematically summarizes recent exploration and attempts of the remediation effectiveness assessment based on the content of pollutants, soil and sediment characteristics, and ecological risks. Moreover, limitations and future research needs of the practical assessment are discussed. These limitations are not conducive to the implementation of the abatement and control programs for soil and sediment contamination. Therefore, more attention should be paid to the evaluation methods for assessing the remediation effectiveness while developing new in situ remediation technologies in future research. Copyright © 2017 Elsevier Ltd. All rights reserved.

Evaluating cadmium bioavailability in contaminated rice paddy soils and assessing potential for contaminant immobilisation with biochar.

PubMed

Kosolsaksakul, Peerapat; Oliver, Ian W; Graham, Margaret C

2018-06-01

Cadmium (Cd) contaminated soils from the Mae Sot district in northwest Thailand, a region in which rice Cd concentrations often exceed health limits (0.4 mg/kg) set by the World Health Organisation, were examined for isotopically exchangeable Cd (Cd E values using a 111 Cd spike) to determine how this rates as a predictor of rice grain Cd in comparison with soil total Cd and solution extractable Cd (using the commonly applied BCR scheme and, in an attempt to distinguish carbonate bound forms, the Tessier soil sequential extraction scheme reagents). Step 1 of the BCR scheme (0.11 M CH 3 COOH) and step 1 of the Tessier scheme (1M MgCl 2 ) showed the highest R 2 values in regressions with rice Cd (91% and 90%, respectively), but all predictors were strongly linked to rice Cd (p < 0.001) and could be used for prediction purposes. One soil, of the six tested, was an exception to this, where all predictors over-estimated grain Cd by a factor of 2.5-5.7, suggesting that rice grain Cd had been restricted here by the differing flooding regime and subsequent changes to redox conditions. E values and Tessier step 1 extractions were closely related, indicating that these measurements access similar pools of soil Cd. Separately, the isotopic exchangeability (representing bioavailability) of Cd was also assessed in two soils amended with rice husk and miscanthus biochars (0, 1, 5, 10, 15 and 20% w/w) in order to assess the utility of the biochars as a soil amendment for immobilising Cd in situ. One soil showed significant reductions in Cd E value at 5% rice husk biochar addition and at 15% miscanthus biochar addition however, based on the E value-rice grain Cd regression relationship previously established, the E values in the amended soils still predicted for a rice Cd concentration above the health limit. In the second soil, neither of the biochars successfully reduced the Cd E value. This indicates that further work is needed to customise biochar properties to suit

Global assessment of exposure to faecal contamination through drinking water based on a systematic review.

PubMed

Bain, Robert; Cronk, Ryan; Hossain, Rifat; Bonjour, Sophie; Onda, Kyle; Wright, Jim; Yang, Hong; Slaymaker, Tom; Hunter, Paul; Prüss-Ustün, Annette; Bartram, Jamie

2014-08-01

To estimate exposure to faecal contamination through drinking water as indicated by levels of Escherichia coli (E. coli) or thermotolerant coliform (TTC) in water sources. We estimated coverage of different types of drinking water source based on household surveys and censuses using multilevel modelling. Coverage data were combined with water quality studies that assessed E. coli or TTC including those identified by a systematic review (n = 345). Predictive models for the presence and level of contamination of drinking water sources were developed using random effects logistic regression and selected covariates. We assessed sensitivity of estimated exposure to study quality, indicator bacteria and separately considered nationally randomised surveys. We estimate that 1.8 billion people globally use a source of drinking water which suffers from faecal contamination, of these 1.1 billion drink water that is of at least 'moderate' risk (>10 E. coli or TTC per 100 ml). Data from nationally randomised studies suggest that 10% of improved sources may be 'high' risk, containing at least 100 E. coli or TTC per 100 ml. Drinking water is found to be more often contaminated in rural areas (41%, CI: 31%-51%) than in urban areas (12%, CI: 8-18%), and contamination is most prevalent in Africa (53%, CI: 42%-63%) and South-East Asia (35%, CI: 24%-45%). Estimates were not sensitive to the exclusion of low quality studies or restriction to studies reporting E. coli. Microbial contamination is widespread and affects all water source types, including piped supplies. Global burden of disease estimates may have substantially understated the disease burden associated with inadequate water services. © 2014 The Authors. Tropical Medicine and International Health published by John Wiley & Sons Ltd.

Global assessment of exposure to faecal contamination through drinking water based on a systematic review

PubMed Central

Bain, Robert; Cronk, Ryan; Hossain, Rifat; Bonjour, Sophie; Onda, Kyle; Wright, Jim; Yang, Hong; Slaymaker, Tom; Hunter, Paul; Prüss-Ustün, Annette; Bartram, Jamie

2014-01-01

Objectives To estimate exposure to faecal contamination through drinking water as indicated by levels of Escherichia coli (E. coli) or thermotolerant coliform (TTC) in water sources. Methods We estimated coverage of different types of drinking water source based on household surveys and censuses using multilevel modelling. Coverage data were combined with water quality studies that assessed E. coli or TTC including those identified by a systematic review (n = 345). Predictive models for the presence and level of contamination of drinking water sources were developed using random effects logistic regression and selected covariates. We assessed sensitivity of estimated exposure to study quality, indicator bacteria and separately considered nationally randomised surveys. Results We estimate that 1.8 billion people globally use a source of drinking water which suffers from faecal contamination, of these 1.1 billion drink water that is of at least ‘moderate’ risk (>10 E. coli or TTC per 100 ml). Data from nationally randomised studies suggest that 10% of improved sources may be ‘high’ risk, containing at least 100 E. coli or TTC per 100 ml. Drinking water is found to be more often contaminated in rural areas (41%, CI: 31%–51%) than in urban areas (12%, CI: 8–18%), and contamination is most prevalent in Africa (53%, CI: 42%–63%) and South-East Asia (35%, CI: 24%–45%). Estimates were not sensitive to the exclusion of low quality studies or restriction to studies reporting E. coli. Conclusions Microbial contamination is widespread and affects all water source types, including piped supplies. Global burden of disease estimates may have substantially understated the disease burden associated with inadequate water services. PMID:24811893

Payload/orbiter contamination control requirement study

NASA Technical Reports Server (NTRS)

Bareiss, L. E.; Rantanen, R. O.; Ress, E. B.

1974-01-01

A study was conducted to determine and quantify the expected particulate and molecular on-orbit contaminant environment for selected space shuttle payloads as a result of major shuttle orbiter contamination sources. Individual payload susceptibilities to contamination are reviewed. The risk of payload degradation is identified and preliminary recommendations are provided concerning the limiting factors which may depend on operational activities associated with the payload/orbiter interface or upon independent payload functional activities. A basic computer model of the space shuttle orbiter which includes a representative payload configuration is developed. The major orbiter contamination sources, locations, and flux characteristics based upon available data have been defined and modeled.

Assessing soil and groundwater contamination from biofuel spills.

PubMed

Chen, Colin S; Shu, Youn-Yuen; Wu, Suh-Huey; Tien, Chien-Jung

2015-03-01

Future modifications of fuels should include evaluation of the proposed constituents for their potential to damage environmental resources such as the subsurface environment. Batch and column experiments were designed to simulate biofuel spills in the subsurface environment and to evaluate the sorption and desorption behavior of target fuel constituents (i.e., monoaromatic and polyaromatic hydrocarbons) in soil. The extent and reversibility of the sorption of aromatic biofuel constituents onto soil were determined. When the ethanol content in ethanol-blended gasoline exceeded 25%, enhanced desorption of the aromatic constituents to water was observed. However, when biodiesel was added to diesel fuel, the sorption of target compounds was not affected. In addition, when the organic carbon content of the soil was higher, the desorption of target compounds into water was lower. The empirical relationships between the organic-carbon normalized sorption coefficient (Koc) and water solubility and between Koc and the octanol-water partition coefficient (Kow) were established. Column experiments were carried out for the comparison of column effluent concentration/mass from biofuel-contaminated soil. The dissolution of target components depended on chemical properties such as the hydrophobicity and total mass of biofuel. This study provides a basis for predicting the fate and transport of hydrophobic organic compounds in the event of a biofuel spill. The spill scenarios generated can assist in the assessment of biofuel-contaminated sites.

Molecular Epidemiology of a Pseudomonas aeruginosa Hospital Outbreak Driven by a Contaminated Disinfectant-Soap Dispenser

PubMed Central

Lanini, Simone; D'Arezzo, Silvia; Puro, Vincenzo; Martini, Lorena; Imperi, Francesco; Piselli, Pierluca; Montanaro, Marco; Paoletti, Simonetta; Visca, Paolo; Ippolito, Giuseppe

2011-01-01

Background and Objective Pseudomonas aeruginosa infection represents a main cause of morbidity and mortality among immunocompromised patients. This study describes a fatal epidemic of P. aeruginosa that occurred in a hematology unit in Italy. Methods Retrospective cohort study, prospective surveillance, auditing, extensive testing on healthcare workers and environmental investigation were performed to define the dynamics and potential causes of transmission. RAPD, macrorestriction analyses and sequence typing were used to define relationships between P. aeruginosa isolates. Results Eighteen cases of infection were identified in the different phases of the investigation. Of these, five constitute a significant molecular cluster of infection. A P. aeruginosa strain with the same genetic fingerprint and sequence type (ST175) as clinical isolates strain was also isolated from a heavily contaminated triclosan soap dispenser. Discussion and Conclusions Our results are consistent with the hypothesis that patients became indirectly infected, e.g., during central venous catheter handling through contaminated items, and that the triclosan soap dispenser acted as a common continuous source of P. aeruginosa infection. Since P. aeruginosa is intrinsically unsusceptible to triclosan, the use of triclosan-based disinfectant formulations should be avoided in those healthcare settings hosting patients at high risk of P. aeruginosa infection. PMID:21359222

Modeling Contamination Migration on the Chandra X-ray Observatory II

NASA Technical Reports Server (NTRS)

O'Dell, Steve; Swartz, Doug; Tice, Neil; Plucinsky, Paul; Grant, Catherine; Marshall, Herman; Vikhlinin, Alexey

2013-01-01

During its first 14 years of operation, the cold (about -60degC) optical blocking filter of the Advanced CCD Imaging Spectrometer (ACIS), aboard the Chandra X-ray Observatory, has accumulated a growing layer of molecular contamination that attenuates low-energy x rays. Over the past few years, the accumulation rate, spatial distribution, and composition may have changed, perhaps partially related to changes in the operating temperature of the ACIS housing. This evolution of the accumulation of the molecular contamination has motivated further analysis of contamination migration on the Chandra X-ray Observatory, particularly within and near the ACIS cavity. To this end, the current study employs a higher-fidelity geometric model of the ACIS cavity, detailed thermal modeling based upon monitored temperature data, and an accordingly refined model of the molecular transport.

Integration of analytical and biological measurements for assessing the effects of contaminants present at Great Lakes areas of concern

EPA Science Inventory

Assessing the potential biological impacts of complex contaminant mixtures in aquatic environments is often a challenge for ecotoxicologists. Instrumental analysis of site waters provides insights into the occurrence of contaminants, but provides little information about possibl...

A Review of the Field on Children’s Exposure to Environmental Contaminants: A Risk Assessment Approach

PubMed Central

Ferguson, Alesia; Penney, Rosalind; Solo-Gabriele, Helena

2017-01-01

Background: Children must be recognized as a sensitive population based on having biological systems and organs in various stages of development. The processes of absorption, distribution, metabolism and elimination of environmental contaminants within a child’s body are considered less advanced than those of adults, making them more susceptible to disease outcomes following even small doses. Children’s unique activities of crawling and practicing increased hand-to-mouth ingestion also make them vulnerable to greater exposures by certain contaminants within specific environments. Approach: There is a need to review the field of children’s environmental exposures in order to understand trends and identify gaps in research, which may lead to better protection of this vulnerable and sensitive population. Therefore, explored here are previously published contemporary works in the broad area of children’s environmental exposures and potential impact on health from around the world. A discussion of children’s exposure to environmental contaminants is best organized under the last four steps of a risk assessment approach: hazard identification, dose-response assessment, exposure assessment (including children’s activity patterns) and risk characterization. We first consider the many exposure hazards that exist in the indoor and outdoor environments, and emerging contaminants of concern that may help guide the risk assessment process in identifying focus areas for children. A section on special diseases of concern is also included. Conclusions: The field of children’s exposures to environmental contaminants is broad. Although there are some well-studied areas offering much insight into children exposures, research is still needed to further our understanding of exposures to newer compounds, growing disease trends and the role of gene-environment interactions that modify adverse health outcomes. It is clear that behaviors of adults and children play a role in

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.

Assessment of toxic metal contamination using a regional lithogenic geochemical background, Pampean area river basin, Argentina.

PubMed

Castro, Liliana Norma; Rendina, Alicia Elena; Orgeira, Maria Julia

2018-06-15

Contamination assessment in riverbed sediments depends on the accurate determination of the background values. The aim of this study is to assess the degree of contamination and to evaluate the most adequate background for the determination of anthropogenic contamination in Cd, Cr, Cu, Ni, Pb and Zn in bed sediments of the Pampean area river basin (Matanza-Riachuelo River and tributary streams), Argentina. The geo-accumulation index (Igeo) values were calculated using selected lithogenic backgrounds (loess, loessoid sediments and paleosoils), the metal concentrations in the residual fraction (F4) in riverbed sediments and a global average shale often applied in the estimation of toxic metal Igeo. The IgeoF4, IgeoLZB and most of the others Igeos, indicated that in land areas used mainly for agriculture and cattle grazing, the superficial sediments were uncontaminated with Cd, Cr, Cu and Zn, and slightly contaminated with Ni and Pb. Conversely, in those areas dedicated to urban and industrial use, the metal contamination was greater. Overall, the relatively significant anthropogenic contamination of Cr > Pb ≥ Cu > Zn > Ni > Cd in the Riachuelo River area was associated with metallurgic activities, tanning and industrial waste. The comparative analysis of different values suggested that Buenos Aires' "pristine" loess could be recommended to evaluate the Igeo index of riverbed sediments in the Pampean area. To enhance the use of the selected background, the normalized enrichment factor using Al. In this study case, the Igeo and the EF using LZB background display the same trend, showing the greatest degree of contamination, as would be expected, in Riachuelo samples (RIA 1 and RIA 2) located in the urban/industrial area. Copyright © 2018 Elsevier B.V. All rights reserved.

Assessment of trace metals contamination in the coastal sediments of the Egyptian Mediterranean coast

NASA Astrophysics Data System (ADS)

El Baz, Sherif M.; Khalil, Mohamed M.

2018-07-01

Trace metals contamination has been recently increased in the Egyptian Mediterranean coast owing to the nearby anthropological activities. This investigation aimed to detect the concentrations of six different trace metals (Fe, Mn, Cu, Cd, Pb and Zn) in surface sediments from the central part of the Egyptian Mediterranean coast, and to assess their state of contamination from different indices and risk factor calculations. Mean concentrations of Cu, Pb and Zn were lower and the mean concentration of Cd was higher compared to the background values. The assessment of pollution was mainly based on the contamination indices. Based on the contamination factor, Pb was the most enriched element followed by Cd, Mn, Zn and Cu. Most of the sites show low contamination with respect to Pb, Mn, Cd, Fe, Zn and Cu. The pollution load index also suggests that all the coastal sediments are unpolluted. According to the geoaccumulation index, the sediments were classified into unpolluted with Mn, Cd, Fe and Pb, and unpolluted to moderately polluted with Pb. Risk evaluation revealed that Cd had the greatest ecological risk, followed by Pb, Cu, Mn, while Zn had the lowest risk. With the aid of statistical methods, the origin of metals is classified into two clusters (A and B). Group A consists of Fe, Mn and Cu, whereas group B contains Zn, Pb and Cd. In the first cluster Fe and Mn are joined to each other at a positive and significant similarity (0.68). Fe is recognized as an indicator of lithogenous origin, therefore, its higher similarity with Mn may be indicative of the similar origin for Manganese. In the second cluster Pb and Zn are joined to each other at a positive and significant similarity (0.80). Pb is recognized as an indicator of anthropogenic origin, therefore, its higher similarity with Zn may be indicative of the similar origin for Zinc.

Heavy metal contamination and risk assessment in water, paddy soil, and rice around an electroplating plant.

PubMed

Liu, Jie; Zhang, Xue-Hong; Tran, Henry; Wang, Dun-Qiu; Zhu, Yi-Nian

2011-11-01

The objective of this paper is to assess the impact of long-term electroplating industrial activities on heavy metal contamination in agricultural soils and potential health risks for local residents. Water, soil, and rice samples were collected from sites upstream (control) and downstream of the electroplating wastewater outlet. The concentrations of heavy metals were determined by an atomic absorption spectrophotometer. Fractionation and risk assessment code (RAC) were used to evaluate the environmental risks of heavy metals in soils. The health risk index (HRI) and hazard index (HI) were calculated to assess potential health risks to local populations through rice consumption. Hazardous levels of Cu, Cr, and Ni were observed in water and paddy soils at sites near the plant. According to the RAC analysis, the soils showed a high risk for Ni and a medium risk for Cu and Cr at certain sites. The rice samples were primarily contaminated with Ni, followed by Cr and Cu. HRI values >1 were not found for any heavy metal. However, HI values for adults and children were 2.075 and 1.808, respectively. Water, paddy soil, and rice from the studied area have been contaminated by Cu, Cr, and Ni. The contamination of these elements is related to the electroplating wastewater. Although no single metal poses health risks for local residents through rice consumption, the combination of several metals may threaten the health of local residents. Cu and Ni are the key components contributing to the potential health risks.

A multi-metric assessment of environmental contaminant exposure and effects in an urbanized reach of the Charles River near Watertown, Massachusetts

USGS Publications Warehouse

Smith, Stephen B.; Anderson, Patrick J.; Baumann, Paul C.; DeWeese, Lawrence R.; Goodbred, Steven L.; Coyle, James J.; Smith, David S.

2012-01-01

The Charles River Project provided an opportunity to simultaneously deploy a combination of biomonitoring techniques routinely used by the U.S. Geological Survey National Water Quality Assessment Program, the Biomonitoring of Environmental Status and Trends Project, and the Contaminant Biology Program at an urban site suspected to be contaminated with polycyclic aromatic hydrocarbons. In addition to these standardized methods, additional techniques were used to further elucidate contaminant exposure and potential impacts of exposure on biota. The purpose of the study was to generate a comprehensive, multi-metric data set to support assessment of contaminant exposure and effects at the site. Furthermore, the data set could be assessed to determine the relative performance of the standardized method suites typically used by the National Water Quality Assessment Program and the Biomonitoring of Environmental Status and Trends Project, as well as the additional biomonitoring methods used in the study to demonstrate ecological effects of contaminant exposure. The Contaminant Effects Workgroup, an advisory committee of the U.S. Geological Survey/Contaminant Biology Program, identified polycyclic aromatic hydrocarbons as the contaminant class of greatest concern in urban streams of all sizes. The reach of the Charles River near Watertown, Massachusetts, was selected as the site for this study based on the suspected presence of polycyclic aromatic hydrocarbon contamination and the presence of common carp (Cyprinus carpio), largemouth bass (Micropterus salmoides), and white sucker (Catostomus commersoni). All of these fish have extensive contaminant-exposure profiles related to polycyclic aromatic hydrocarbons and other environmental contaminants. This project represented a collaboration of universities, Department of the Interior bureaus including multiple components of the USGS (Biological Resources Discipline and Water Resources Discipline Science Centers, the

Assessment of contaminant concentrations in sediments, fish and mussels sampled from the North Atlantic and European regional seas within the ICON project.

PubMed

Robinson, Craig D; Webster, Lynda; Martínez-Gómez, Concepción; Burgeot, Thierry; Gubbins, Matthew J; Thain, John E; Vethaak, A Dick; McIntosh, Alistair D; Hylland, Ketil

2017-03-01

Understanding the status of contaminants in the marine environment is a requirement of European Union Directives and the Regional Seas Conventions, so that measures to reduce pollution can be identified and their efficacy assessed. The international ICON workshop (Hylland et al., in this issue) was developed in order to test an integrated approach to assessing both contaminant concentrations and their effects. This paper describes and assesses the concentrations of trace metals, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls in sediments, mussels, and fish collected from estuarine, coastal and offshore waters from Iceland to the Mediterranean Sea. For organic contaminants, concentrations progressively increased from Iceland, to the offshore North Sea, to the coastal seas, and were highest in estuaries. Metals had a more complex distribution, reflecting local anthropogenic inputs, natural sources and hydrological conditions. Use of internationally recognised assessment criteria indicated that at no site were concentrations of all contaminants at background and that concentrations of some contaminants were of significant concern in all areas, except the central North Sea. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

Assessment of Methods for Estimating Risk to Birds from Ingestion of Contaminated Grit Particles (Final Report)

EPA Science Inventory

The U.S. EPA Ecological Risk Assessment Support Center (ERASC) announced the release of the final report entitled, Assessment of Methods for Estimating Risk to Birds from Ingestion of Contaminated Grit Particles. This report evaluates approaches for estimating the probabi...

Molecular and Physiological Effects on the Small Intestine of Weaner Pigs Following Feeding with Deoxynivalenol-Contaminated Feed.

PubMed

Pasternak, J Alex; Aiyer, Vaishnavi Iyer Aka; Hamonic, Glenn; Beaulieu, A Denise; Columbus, Daniel A; Wilson, Heather L

2018-01-12

We intended to assess how exposure of piglets to deoxynivalenol (DON)-contaminated feed impacted their growth, immune response and gut development. Piglets were fed traditional Phase I, Phase II and Phase III diets with the control group receiving 0.20-0.40 ppm DON (referred to as the Control group) and treatment group receiving much higher level of DON-contaminated wheat (3.30-3.80 ppm; referred to as DON-contaminated group). Feeding a DON-contaminated diet had no impact on average daily feed intake (ADFI) ( p < 0.08) or average daily gain (ADG) ( p > 0.10) but it did significantly reduce body weight over time relative to the control piglets ( p < 0.05). Cytokine analysis after initial exposure to the DON-contaminated feed did not result in significant differences in serum interleukin (IL) IL1β, IL-8, IL-13, tumor necrosis factor (TNF)-α or interferon (IFN)-γ. After day 24, no obvious changes in jejunum or ileum gut morphology, histology or changes in gene expression for IL-1β, IL-6, IL-10, TNFα, or Toll-like receptor (TLR)-4 genes. IL-8 showed a trend towards increased expression in the ileum in DON-fed piglets. A significant increase in gene expression for claudin (CLDN) 7 gene expression and a trend towards increased CLDN 2-expression was observed in the ileum in piglets fed the highly DON-contaminated wheat. Because CLDN localization was not negatively affected, we believe that it is unlikely that gut permeability was affected. Exposure to DON-contaminated feed did not significantly impact weaner piglet performance or gut physiology.

78 FR 68058 - Next Generation Risk Assessment: Incorporation of Recent Advances in Molecular, Computational...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-13

... Generation Risk Assessment: Incorporation of Recent Advances in Molecular, Computational, and Systems Biology... Generation Risk Assessment: Incorporation of Recent Advances in Molecular, Computational, and Systems Biology..., computational, and systems biology data can better inform risk assessment. This draft document is available for...

[Assessment of risk of contamination of drinking water for the health of children in the Tula region].

PubMed

Grigorev, Yu I; Lyapina, N V

2014-01-01

The hygienic analysis of centralized drinking water supply in Tula region was performed. Priority contaminants of drinking water were established. On the base of the application of risk assessment methodology there was calculated carcinogenic risk for children's health. A direct relationship between certain classes of diseases and pollution of drinking water with chemical contaminants has been determined.

Contamination in Orbit of GOES-8

NASA Technical Reports Server (NTRS)

Sanders, Jack T.

2002-01-01

The GOES-8 satellite has lost some of its ability to dissipate heat over time. This is shown by the temperature increases over time of spacecraft and instrument components that are cooled with optical solar reflector (OSR) radiators. Contamination has a significant, well-documented effect on the solar absorptance (a(sub s)) of OSRs. This document attempts to discern how much molecular contamination has collected on the Imager and Sounder radiant coolers by analyzing the increase in temperature of the vacuum cooler housing. In the first part, temperature change is transformed into solar absorptance units by a method devised by ITT. The second part transfomis the solar absorptance gain into a molecular film thickness.

Assessment of molecular marker compounds as an index of the biodegradation of diesel fuel hydrocarbons in soil

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

Voos, G.; Mills, G.; O`Neill, J.

1996-10-01

The weathering of petroleum hydrocarbons in the soil environment is the sum of biological, physical and chemical processes. It is often difficult to clearly discern microbial from abiotic contributions to the overall process. This is especially important in assessing the effectiveness of various in-situ bioremediation technologies. We examined molecular marker compounds, including pristane, phytane, diterpenoid hydrocarbons, farnesane and norpristane, and the ratios n-C17/pristane and n-C18/phytane to evaluate their use as an index of biodegradation of diesel fuel in contaminated soil. The study was conducted using microcosms containing 200 g of contaminated soil. Microcosms were destructively sampled on days 0, 1,more » 2, 4, 8, 14, 33 and 64 of the experiment. The soil was analyzed for straight-chained, branched-chained, and alicyclic petroleum hydrocarbons using high-resolution gas chromatography. Results indicate that by day 33 of the experiment, pristane and phytane were present at significantly greater concentrations than their corresponding n-alkanes and the other marker compounds analyzed. There is a strong correlation between the amount of pristane and phytane present in the soil and the amount of total extractable petroleum hydrocarbons (TEPH) measured during the course of the experiment.« less

Better vacuum by removal of diffusion-pump-oil contaminants

NASA Technical Reports Server (NTRS)

Buggele, A. E.

1975-01-01

The complex problem of why large space simulation chambers do not realize true ultimate vacuum was investigated. Some contaminating factors affecting diffusion pump performance were identified, and some advances in vacuum distillation-fractionation technology were achieved which resulted in a two-decade-or-more lower ultimate pressure. Data are presented to show the overall or individual contaminating effects of commonly used phthalate ester plasticizers of 390 to 530 molecular weight on diffusion pump performance. Methods for removing contaminants from diffusion pump silicone oil during operation and for reclaiming contaminated oil by high-vacuum molecular distillation are described. Conceptual self-cleansing designs and operating procedures are proposed for modifying large diffusion pumps into high-efficiency distillation devices. The potential exists for application of these technological advancements to other disciplines, such as medicine, biomedical materials, metallurgy, refining, and chemical (diffusion-enrichment) processing.

Niobate-based octahedral molecular sieves

DOEpatents

Nenoff, Tina M.; Nyman, May D.

2006-10-17

Niobate-based octahedral molecular sieves having significant activity for multivalent cations and a method for synthesizing such sieves are disclosed. The sieves have a net negatively charged octahedral framework, comprising niobium, oxygen, and octahedrally coordinated lower valence transition metals. The framework can be charge balanced by the occluded alkali cation from the synthesis method. The alkali cation can be exchanged for other contaminant metal ions. The ion-exchanged niobate-based octahedral molecular sieve can be backexchanged in acidic solutions to yield a solution concentrated in the contaminant metal. Alternatively, the ion-exchanged niobate-based octahedral molecular sieve can be thermally converted to a durable perovskite phase waste form.

Niobate-based octahedral molecular sieves

DOEpatents

Nenoff, Tina M.; Nyman, May D.

2003-07-22

Niobate-based octahedral molecular sieves having significant activity for multivalent cations and a method for synthesizing such sieves are disclosed. The sieves have a net negatively charged octahedral framework, comprising niobium, oxygen, and octahedrally coordinated lower valence transition metals. The framework can be charge balanced by the occluded alkali cation from the synthesis method. The alkali cation can be exchanged for other contaminant metal ions. The ion-exchanged niobate-based octahedral molecular sieve can be backexchanged in acidic solutions to yield a solution concentrated in the contaminant metal. Alternatively, the ion-exchanged niobate-based octahedral molecular sieve can be thermally converted to a durable perovskite phase waste form.

GUIDANCE ON SELECTING AGE GROUPS FOR MONITORING AND ASSESSING CHILDHOOD EXPOSURES TO ENVIRONMENTAL CONTAMINANTS

EPA Science Inventory

This guidance document provides a set of early-lifestage age groups for Environmental Protection Agency scientists to consider when assessing children’s exposure to environmental contaminants and the resultant potential dose. These recommended age groups are based on current und...

General contamination criteria for optical surfaces. [instrument performance losses in spaceborne conditions

NASA Technical Reports Server (NTRS)

Bremer, J. C.

1982-01-01

Physical models are developed for establishing criteria to decide on the acceptable contamination level of optical devices in space-borne conditions. Optical systems can be degraded in terms of decreased throughput, i.e., transmissivity or reflectivity, or increases in the total integrated scatter (TIS). Performance losses can be caused by particulate accretion, molecular film accretion, and impact cratering. A quantitative relationship is defined for film thickness and loss of throughput. Formulas are also developed for cases where induced surface defects are larger than the desired viewing wavelengths, or smaller or of the same order of the observed wavelengths. The techniques are used to quantify the degradation of a VUV solar coronagraph, a VUV stellar telescope, and a solar cell due to TIS. Applications are projected for estimating the contamination sensitivity of specific instruments, assessing the contamination hazard from known particulates, or to define clean room standards.

A case study of risk assessment in contaminated site remediation in China

NASA Astrophysics Data System (ADS)

Ye, S.; Guo, J.; Wu, J.; Wang, J.; Chien, C.; Stahl, R.; Mack, E.; Grosso, N.

2013-12-01

A field site in Nanjing, China was selected for a case study of risk assessment in contaminated site remediation. This site is about 100m long and 100m wide. A chemical plant (1999-2010) at the site manufactured optical brightener PF, 2-Amino-4-methylphenol and 2-Nitro-4-methylphenol, totally three products. Soil and groundwater samples were collected and analyzed for PPL 126 (126 pollutants in the 'Priority Pollutants List' issued by US EPA). Values of the Dutch Standards were used as the screening criteria for soil and ground water. Low levels of ethylbenezene, chlorobenzene, 1,3-dichlorobenzene and 1,4- dichlorobenzene were detected in one soil sample. Concentrations above Dutch Target Value (DTV) of benzene, toluene, ethylbenzene, chlorobenzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, and/or 1,2,4-trichlorobenzene, phenol, and/or 2,4-dichlorophenol were exhibited in two groundwater samples. The ground water was especially highly impacted by bichlorobenzenes and trichlorobenzenes. The maximum concentration of impacts was 7.3 mg/L of 1,2,4-trichlorobenzene in groundwater which was 730 times higher than Dutch Intervention Values (DIV). Risk of soil and groundwater at this site was assessed according to the guidelines issued by Chinese MEP and US EPA, respectively. Finally, remedy techniques were selected according to the result of risk assessment and the characteristics of hydrogeology conditions and contaminants.

NASA Technology Protects Webb Telescope from Contamination

NASA Image and Video Library

2015-06-25

Contamination from organic molecules can harm delicate instruments and engineers are taking special care at NASA to prevent that from affecting the James Webb Space Telescope (and all satellites and instruments). Recently, Nithin Abraham, a Thermal Coatings Engineer placed Molecular Adsorber Coating or "MAC" panels in the giant chamber where the Webb telescope will be tested. This contamination can occur through a process when a vapor or odor is emitted by a substance. This is called "outgassing." The "new car smell" is an example of that, and is unhealthy for people and sensitive satellite instruments. So, NASA engineers have created a new way to protect those instruments from the damaging effects of contamination coming from outgassing. "The Molecular Adsorber Coating (MAC) is a NASA Goddard coatings technology that was developed to adsorb or entrap outgassed molecular contaminants for spaceflight applications," said Nithin Abraham, Thermal Coatings Engineer at NASA's Goddard Space Flight Center in Greenbelt, Maryland. MAC is currently serving as an innovative contamination mitigation tool for Chamber A operations at NASA Johnson Space Center in Houston, Texas. MAC can be used to keep outgassing from coming in from outside areas or to capture outgassing directly from hardware, components, and within instrument cavities. In this case, MAC is helping by capturing outgassed contaminants outside the test chamber from affecting the Webb components. MAC is expected to capture the outgassed contaminants that exist in the space of the vacuum chamber (not from the Webb components). Credit: NASA/GoddardChris Gunn Read more: www.nasa.gov/feature/goddard/nasa-technology-protects-web... NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge

Soil sampling strategies for site assessments in petroleum-contaminated areas.

PubMed

Kim, Geonha; Chowdhury, Saikat; Lin, Yen-Min; Lu, Chih-Jen

2017-04-01

Environmental site assessments are frequently executed for monitoring and remediation performance evaluation purposes, especially in total petroleum hydrocarbon (TPH)-contaminated areas, such as gas stations. As a key issue, reproducibility of the assessment results must be ensured, especially if attempts are made to compare results between different institutions. Although it is widely known that uncertainties associated with soil sampling are much higher than those with chemical analyses, field guides or protocols to deal with these uncertainties are not stipulated in detail in the relevant regulations, causing serious errors and distortion of the reliability of environmental site assessments. In this research, uncertainties associated with soil sampling and sample reduction for chemical analysis were quantified using laboratory-scale experiments and the theory of sampling. The research results showed that the TPH mass assessed by sampling tends to be overestimated and sampling errors are high, especially for the low range of TPH concentrations. Homogenization of soil was found to be an efficient method to suppress uncertainty, but high-resolution sampling could be an essential way to minimize this.

Molecular detection of pathogens in water--the pros and cons of molecular techniques.

PubMed

Girones, Rosina; Ferrús, Maria Antonia; Alonso, José Luis; Rodriguez-Manzano, Jesus; Calgua, Byron; Corrêa, Adriana de Abreu; Hundesa, Ayalkibet; Carratala, Anna; Bofill-Mas, Sílvia

2010-08-01

Pollution of water by sewage and run-off from farms produces a serious public health problem in many countries. Viruses, along with bacteria and protozoa in the intestine or in urine are shed and transported through the sewer system. Even in highly industrialized countries, pathogens, including viruses, are prevalent throughout the environment. Molecular methods are used to monitor viral, bacterial, and protozoan pathogens, and to track pathogen- and source-specific markers in the environment. Molecular techniques, specifically polymerase chain reaction-based methods, provide sensitive, rapid, and quantitative analytical tools with which to study such pathogens, including new or emerging strains. These techniques are used to evaluate the microbiological quality of food and water, and to assess the efficiency of virus removal in drinking and wastewater treatment plants. The range of methods available for the application of molecular techniques has increased, and the costs involved have fallen. These developments have allowed the potential standardization and automation of certain techniques. In some cases they facilitate the identification, genotyping, enumeration, viability assessment, and source-tracking of human and animal contamination. Additionally, recent improvements in detection technologies have allowed the simultaneous detection of multiple targets in a single assay. However, the molecular techniques available today and those under development require further refinement in order to be standardized and applicable to a diversity of matrices. Water disinfection treatments may have an effect on the viability of pathogens and the numbers obtained by molecular techniques may overestimate the quantification of infectious microorganisms. The pros and cons of molecular techniques for the detection and quantification of pathogens in water are discussed. (c) 2010 Elsevier Ltd. All rights reserved.

Testing contamination risk assessment methods for toxic elements from mine waste sites

NASA Astrophysics Data System (ADS)

Abdaal, A.; Jordan, G.; Szilassi, P.; Kiss, J.; Detzky, G.

2012-04-01

Major incidents involving mine waste facilities and poor environmental management practices have left a legacy of thousands of contaminated sites like in the historic mining areas in the Carpathian Basin. Associated environmental risks have triggered the development of new EU environmental legislation to prevent and minimize the effects of such incidents. The Mine Waste Directive requires the risk-based inventory of all mine waste sites in Europe by May 2012. In order to address the mining problems a standard risk-based Pre-selection protocol has been developed by the EU Commission. This paper discusses the heavy metal contamination in acid mine drainage (AMD) for risk assessment (RA) along the Source-Pathway-Receptor chain using decision support methods which are intended to aid national and regional organizations in the inventory and assessment of potentially contaminated mine waste sites. Several recognized methods such as the European Environmental Agency (EEA) standard PRAMS model for soil contamination, US EPA-based AIMSS and Irish HMS-IRC models for RA of abandoned sites are reviewed, compared and tested for the mining waste environment. In total 145 ore mine waste sites have been selected for scientific testing using the EU Pre-selection protocol as a case study from Hungary. The proportion of uncertain to certain responses for a site and for the total number of sites may give an insight of specific and overall uncertainty in the data we use. The Pre-selection questions are efficiently linked to a GIS system as database inquiries using digital spatial data to directly generate answers. Key parameters such as distance to the nearest surface and ground water bodies, to settlements and protected areas are calculated and statistically evaluated using STATGRAPHICS® in order to calibrate the RA models. According to our scientific research results, of the 145 sites 11 sites are the most risky having foundation slope >20o, 57 sites are within distance <500m to the

Groundwater contamination and risk assessment of industrial complex in Busan Metropolitan City, Korea

NASA Astrophysics Data System (ADS)

Hamm, S.-Y.; Ryu, S. M.; Cheong, J.-Y.; Woo, Y.-J.

2003-04-01

In Korea, the potential of groundwater contamination in urban areas is increasing by industrial and domestic waste waters, leakage from oil storage tanks and sewage drains, leachate from municipal landfill sites and so on. Nowadays, chlorinated organic compounds such as trichloroethylene (TCE) and tetrachloroethylene (PCE), which are driving residential area as well as industrial area, are recognized as major hazardous contaminants. As well known, TCE is wisely used industrial activities such as degreasing, metal stripping, chemical manufacturing, pesticide production, coal gasification plants, creosote operation, and also used in automobile service centers, photo shops and laundries as cleaning solvent. Thus, groundwater protection in urban areas is important issue in Korea This study is to understand groundwater quality and contamination characteristics and to estimate risk assessment in Sasang industrial complex, Busan Metropolitan City. Busan Metropolitan City is located on southeastern coast of the Korean peninsula and is the second largest city in South Korea with a population of 3.8 millions. The geology of the study area is composed of andesite, andesitic tuff, biotite granite and alluvium (Kim et al., 1998). However, geology cannot be identified on the surface due to pavement and buildings. According to drill logs in the study area, the geologic section consists in landfill, fine sand, clay, gravelly clay, and biotite granite from the surface. Biotite granite appears 5.5- 6 m depth. Groundwater samples were collected at twenty sites in Sasang industrial complex. The groundwater samples are plotted on Piper's trilinear diagram, which indicates Ca-Cl2 type. The groundwater may be influenced by salt water because Sasang industrial complex is located near the mouse of Nakdong river that flows to the South Sea. The Ca-Cl2 water type may be partly influenced by anthropogenic contamination in the study area, since water type in granite area generally belongs Ca

Molecular profiling--a tool for addressing emerging gaps in the comparative risk assessment of GMOs.

PubMed

Heinemann, Jack A; Kurenbach, Brigitta; Quist, David

2011-10-01

Assessing the risks of genetically modified organisms (GMOs) is required by both international agreement and domestic legislation. Many view the use of the "omics" tools for profiling classes of molecules as useful in risk assessment, but no consensus has formed on the need or value of these techniques for assessing the risks of all GMOs. In this and many other cases, experts support case-by-case use of molecular profiling techniques for risk assessment. We review the latest research on the applicability and usefulness of molecular profiling techniques for GMO risk assessment. As more and more kinds of GMOs and traits are developed, broader use of molecular profiling in a risk assessment may be required to supplement the comparative approach to risk assessment. The literature-based discussions on the use of profiling appear to have settled on two findings: 1. profiling techniques are reliable and relevant, at least no less so than other techniques used in risk assessment; and 2. although not required routinely, regulators should be aware of when they are needed. The dismissal of routine molecular profiling may be confusing to regulators who then lack guidance on when molecular profiling might be worthwhile. Molecular profiling is an important way to increase confidence in risk assessments if the profiles are properly designed to address relevant risks and are applied at the correct stage of the assessment. Copyright © 2011 Elsevier Ltd. All rights reserved.

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

[Contaminants from food packaging : New developments in risk assessment].

PubMed

Pfaff, Karla; Wölfle, Detlef; Luch, Andreas

2017-07-01

Diverse materials intended for contact with food are important sources of food contamination. Harmonised European regulations including whitelists (so-called "positive lists") of substances along with migration limits and restrictions exist for plastics and regenerated cellulose films only. The European Food Safety Authority (EFSA) is responsible for the risk assessment of substances prior to their authorization and inclusion into the positive lists. In 2016 the EFSA issued an opinion on recent developments in the risk assessment of substances migrating into food for public consideration. Also migration related to non-intentionally added substances (NIASs), e. g. impurities, degradations products or oligomers, may be relevant for risk assessment. For substances migrating in quantities up to 50 ppb the requested data are restricted to genotoxicity testing based on a tiered approach for toxicological data requirements. In the case of higher migration levels (>50 ppb) experimental animal studies are also requested. Along with an evaluation of the available information, toxicological data on structurally similar substances may be used for the assessment if sufficiently justified with the aim to reduce animal studies as far as possible. For the risk assessment of NIASs it is possible to apply in silico methods in the absence of experimental toxicological data. Additionally, new technologies such as the use of nanomaterials, active and intelligent packaging and recycled plastics are challenging tasks in EFSA's risk assessment in accordance with the regulations by the European Commission.

Integration of analytical and biological measurements for assessing the effects of contaminants present at a Great Lakes area of concern

EPA Science Inventory

Assessing the potential biological impacts of complex contaminant mixtures in aquatic environments is a challenge. Instrumental analyses of site waters provide insights into the occurrence of contaminants, but provide little information about possible effects. Biological measur...

Assessment of radiation exposure from cesium-137 contaminated roads for epidemiological studies in Seoul, Korea.

PubMed

Lee, Yun-Keun; Ju, Young-Su; Lee, Won Jin; Hwang, Seung Sik; Yim, Sang-Hyuk; Yoo, Sang-Chul; Lee, Jieon; Choi, Kyung-Hwa; Burm, Eunae; Ha, Mina

2015-01-01

We aimed to assess the radiation exposure for epidemiologic investigation in residents exposed to radiation from roads that were accidentally found to be contaminated with radioactive cesium-137 ((137)Cs) in Seoul. Using information regarding the frequency and duration of passing via the (137)Cs contaminated roads or residing/working near the roads from the questionnaires that were obtained from 8875 residents and the measured radiation doses reported by the Nuclear Safety and Security Commission, we calculated the total cumulative dose of radiation exposure for each person. Sixty-three percent of the residents who responded to the questionnaire were considered as ever-exposed and 1% of them had a total cumulative dose of more than 10 mSv. The mean (minimum, maximum) duration of radiation exposure was 4.75 years (0.08, 11.98) and the geometric mean (minimum, maximum) of the total cumulative dose was 0.049 mSv (<0.001, 35.35) in the exposed. An individual exposure assessment was performed for an epidemiological study to estimate the health risk among residents living in the vicinity of (137)Cs contaminated roads. The average exposure dose in the exposed people was less than 5% of the current guideline.

Environmental impacts of remediation of a trichloroethene-contaminated site: life cycle assessment of remediation alternatives.

PubMed

Lemming, Gitte; Hauschild, Michael Z; Chambon, Julie; Binning, Philip J; Bulle, Cécile; Margni, Manuele; Bjerg, Poul L

2010-12-01

The environmental impacts of remediation of a chloroethene-contaminated site were evaluated using life cycle assessment (LCA). The compared remediation options are (i) in situ bioremediation by enhanced reductive dechlorination (ERD), (ii) in situ thermal desorption (ISTD), and (iii) excavation of the contaminated soil followed by off-site treatment and disposal. The results showed that choosing the ERD option will reduce the life-cycle impacts of remediation remarkably compared to choosing either ISTD or excavation, which are more energy-demanding. In addition to the secondary impacts of remediation, this study includes assessment of local toxic impacts (the primary impact) related to the on-site contaminant leaching to groundwater and subsequent human exposure via drinking water. The primary human toxic impacts were high for ERD due to the formation and leaching of chlorinated degradation products, especially vinyl chloride during remediation. However, the secondary human toxic impacts of ISTD and excavation are likely to be even higher, particularly due to upstream impacts from steel production. The newly launched model, USEtox, was applied for characterization of primary and secondary toxic impacts and combined with a site-dependent fate model of the leaching of chlorinated ethenes from the fractured clay till site.

Assessment of levels of bacterial contamination of large wild game meat in Europe.

PubMed

Membré, Jeanne-Marie; Laroche, Michel; Magras, Catherine

2011-08-01

The variations in prevalence and levels of pathogens and fecal contamination indicators in large wild game meat were studied to assess their potential impact on consumers. This analysis was based on hazard analysis, data generation and statistical analysis. A total of 2919 meat samples from three species (red deer, roe deer, wild boar) were collected at French game meat traders' facilities using two sampling protocols. Information was gathered on the types of meat cuts (forequarter or haunch; first sampling protocol) or type of retail-ready meat (stewing meat or roasting meat; second protocol), and also on the meat storage conditions (frozen or chilled), country of origin (eight countries) and shooting season (autumn, winter, spring). The samples were analyzed in both protocols for detection and enumeration of Escherichia coli, coagulase+staphylococci and Clostridium perfringens. In addition, detection and enumeration of thermotolerant coliforms and Listeria monocytogenes were performed for samples collected in the first and second protocols, respectively. The levels of bacterial contamination of the raw meat were determined by performing statistical analysis involving probabilistic techniques and Bayesian inference. C. perfringens was found in the highest numbers for the three indicators of microbial quality, hygiene and good handling, and L. monocytogenes in the lowest. Differences in contamination levels between game species and between meats distributed as chilled or frozen products were not significant. These results might be included in quantitative exposure assessments. Copyright © 2011 Elsevier Ltd. All rights reserved.

Assessing the chemical contamination dynamics in a mixed land use stream system.

PubMed

Sonne, Anne Th; McKnight, Ursula S; Rønde, Vinni; Bjerg, Poul L

2017-11-15

Traditionally, the monitoring of streams for chemical and ecological status has been limited to surface water concentrations, where the dominant focus has been on general water quality and the risk for eutrophication. Mixed land use stream systems, comprising urban areas and agricultural production, are challenging to assess with multiple chemical stressors impacting stream corridors. New approaches are urgently needed for identifying relevant sources, pathways and potential impacts for implementation of suitable source management and remedial measures. We developed a method for risk assessing chemical stressors in these systems and applied the approach to a 16-km groundwater-fed stream corridor (Grindsted, Denmark). Three methods were combined: (i) in-stream contaminant mass discharge for source quantification, (ii) Toxic Units and (iii) environmental standards. An evaluation of the chemical quality of all three stream compartments - stream water, hyporheic zone, streambed sediment - made it possible to link chemical stressors to their respective sources and obtain new knowledge about source composition and origin. Moreover, toxic unit estimation and comparison to environmental standards revealed the stream water quality was substantially impaired by both geogenic and diffuse anthropogenic sources of metals along the entire corridor, while the streambed was less impacted. Quantification of the contaminant mass discharge originating from a former pharmaceutical factory revealed that several 100 kgs of chlorinated ethenes and pharmaceutical compounds discharge into the stream every year. The strongly reduced redox conditions in the plume result in high concentrations of dissolved iron and additionally release arsenic, generating the complex contaminant mixture found in the narrow discharge zone. The fingerprint of the plume was observed in the stream several km downgradient, while nutrients, inorganics and pesticides played a minor role for the stream health. The

Contamination Effects on EUV Optics

NASA Technical Reports Server (NTRS)

Tveekrem, J.

1999-01-01

During ground-based assembly and upon exposure to the space environment, optical surfaces accumulate both particles and molecular condensibles, inevitably resulting in degradation of optical instrument performance. Currently, this performance degradation (and the resulting end-of-life instrument performance) cannot be predicted with sufficient accuracy using existing software tools. Optical design codes exist to calculate instrument performance, but these codes generally assume uncontaminated optical surfaces. Contamination models exist which predict approximate end-of-life contamination levels, but the optical effects of these contamination levels can not be quantified without detailed information about the optical constants and scattering properties of the contaminant. The problem is particularly pronounced in the extreme ultraviolet (EUV, 300-1,200 A) and far (FUV, 1,200-2,000 A) regimes due to a lack of data and a lack of knowledge of the detailed physical and chemical processes involved. Yet it is in precisely these wavelength regimes that accurate predictions are most important, because EUV/FUV instruments are extremely sensitive to contamination.

ContaMiner and ContaBase: a webserver and database for early identification of unwantedly crystallized protein contaminants

PubMed Central

Hungler, Arnaud; Momin, Afaque; Diederichs, Kay; Arold, Stefan, T.

2016-01-01

Solving the phase problem in protein X-ray crystallography relies heavily on the identity of the crystallized protein, especially when molecular replacement (MR) methods are used. Yet, it is not uncommon that a contaminant crystallizes instead of the protein of interest. Such contaminants may be proteins from the expression host organism, protein fusion tags or proteins added during the purification steps. Many contaminants co-purify easily, crystallize and give good diffraction data. Identification of contaminant crystals may take time, since the presence of the contaminant is unexpected and its identity unknown. A webserver (ContaMiner) and a contaminant database (ContaBase) have been established, to allow fast MR-based screening of crystallographic data against currently 62 known contaminants. The web-based ContaMiner (available at http://strube.cbrc.kaust.edu.sa/contaminer/) currently produces results in 5 min to 4 h. The program is also available in a github repository and can be installed locally. ContaMiner enables screening of novel crystals at synchrotron beamlines, and it would be valuable as a routine safety check for ‘crystallization and preliminary X-ray analysis’ publications. Thus, in addition to potentially saving X-ray crystallographers much time and effort, ContaMiner might considerably lower the risk of publishing erroneous data. PMID:27980519

A hierarchical approach to ecological assessment of contaminated soils at Aberdeen Proving Ground, USA

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

Kuperman, R.G.

1995-12-31

Despite the expansion of environmental toxicology studies over the past decade, soil ecosystems have largely been ignored in ecotoxicological studies in the United States. The objective of this project was to develop and test the efficacy of a comprehensive methodology for assessing ecological impacts of soil contamination. A hierarchical approach that integrates biotic parameters and ecosystem processes was used to give insight into the mechanisms that lead to alterations in the structure and function of soil ecosystems in contaminated areas. This approach involved (1) a thorough survey of the soil biota to determine community structure, (2) laboratory and field testsmore » on critical ecosystem processes, (3) toxicity trials, and (4) the use of spatial analyses to provide input to the decision-making, process. This methodology appears to, offer an efficient and potentially cost-saving tool for remedial investigations of contaminated sites.« less

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.

Utilizing high-throughput bioassays associated with US EPA ToxCast Program to assess biological activity of environmental contaminants: A case study of chemical mixtures

EPA Science Inventory

Effects-based monitoring and surveillance is increasingly being utilized in conjunction with chemical monitoring to determine potential biological activity associated with environmental contaminants. Supervised approaches targeting specific chemical activity or molecular pathways...

Risk assessment for arsenic-contaminated groundwater along River Indus in Pakistan.

PubMed

Rabbani, Unaib; Mahar, Gohar; Siddique, Azhar; Fatmi, Zafar

2017-02-01

The study determined the risk zone and estimated the population at risk of adverse health effects for arsenic exposure along the bank of River Indus in Pakistan. A cross-sectional survey was conducted in 216 randomly selected villages of one of the districts along River Indus. Wells of ten households from each village were selected to measure arsenic levels. The location of wells was identified using global positioning system device, and spatial variations of the groundwater contamination were assessed using geographical information system tools. Using layers of contaminated drinking water wells according to arsenic levels and population with major landmarks, a risk zone and estimated population at risk were determined, which were exposed to arsenic level ≥10 µg/L. Drinking wells with arsenic levels of ≥10 µg/L were concentrated within 18 km near the river bank. Based on these estimates, a total of 13 million people were exposed to ≥10 µg/L arsenic concentration along the course of River Indus traversing through 27 districts in Pakistan. This information would help the researchers in designing health effect studies on arsenic and policy makers in allocating resources for designing focused interventions for arsenic mitigation in Pakistan. The study methods have implication on similar populations which are affected along rivers due to arsenic contamination.

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

Air analysis in the assessment of fumonisin contamination risk in maize.

PubMed

Torelli, Emanuela; Gubiani, Rino; Firrao, Giuseppe; Cividino, Sirio; Locci, Romano; Gobbi, Emanuela

2010-03-15

In maize-growing areas where fumonisin contamination is endemic, there is an urgent need for novel methods to assess the quality of grain lots before their delivery to common drying and storage collection centres. Aerobiological samples of fungal spores released during harvest were analysed to establish a relationship between fumonisin contamination and the abundance of pathogen propagules collected in the combine harvester using a cyclone and membrane filters. Filter-captured propagules were analysed by direct plating, immunoenzymatic assay of specific Fusarium extracellular polysaccharides and real time polymerase chain reaction of the extracted DNA using fum1, a gene involved in the biosynthesis of fumonisin, as a target. The results showed that time of harvest and environmental conditions strongly influenced the efficiency and performance of the collection system. The data obtained were informative in comparing individual samples collected under similar conditions. The immunoenzymatic assay provided the most reliable data, which improved the ability of a neural network to predict the fumonisin content of lots, when added to agronomic, environmental and phytosanitary data. This is the first attempt to evaluate the Fusarium propagules dispersed during harvesting as a predictive means to assess maize quality. A method based on cyclone/filter capture and immunological detection has been shown to be feasible and to have the potential for the development of a continuous monitoring system, but the prediction capabilities in the present implementation were limited.

The differential relationship between mental contamination and the core dimensions of contact contamination fear.

PubMed

Melli, Gabriele; Bulli, Francesco; Carraresi, Claudia; Tarantino, Federica; Gelli, Simona; Poli, Andrea

2017-01-01

Two types of contamination fear are recognized: contact and mental contamination. Contact contamination appears to be motivated both by harm avoidance and disgust avoidance. This study aimed to examine the relationships between disgust propensity, mental contamination and contact contamination while differentiating between harm avoidance and disgust avoidance in contact contamination. 169 OCD patients completed a set of questionnaires assessing mental contamination, contact contamination, disgust propensity, OCD, anxiety and depression. 1) Contact contamination based on disgust avoidance was more strongly associated with mental contamination and disgust propensity than contact contamination based on harm avoidance; 2) mental contamination significantly predicted contact contamination based on disgust avoidance, while it did not predict contact contamination based on harm avoidance; 3) mental contamination had a significant mediational role in the relationship between disgust propensity and contact contamination motivated by disgust avoidance. Mental contamination plays a role in contact contamination fear when disgust is primarily experienced. Copyright © 2016 Elsevier Ltd. All rights reserved.

Potential Applicability of Assembled Chemical Weapons Assessment Technologies to RCRA Waste Streams and Contaminated Media (PDF)

EPA Pesticide Factsheets

This report provides an evaluation of the potential applicability of Assembled Chemical Weapons Assessment (ACWA) technologies to RCRA waste streams and contaminated media found at RCRA and Superfund sites.

Assessing the prevalence of mycoplasma contamination in cell culture via a survey of NCBI's RNA-seq archive

PubMed Central

Olarerin-George, Anthony O.; Hogenesch, John B.

2015-01-01

Mycoplasmas are notorious contaminants of cell culture and can have profound effects on host cell biology by depriving cells of nutrients and inducing global changes in gene expression. Over the last two decades, sentinel testing has revealed wide-ranging contamination rates in mammalian culture. To obtain an unbiased assessment from hundreds of labs, we analyzed sequence data from 9395 rodent and primate samples from 884 series in the NCBI Sequence Read Archive. We found 11% of these series were contaminated (defined as ≥100 reads/million mapping to mycoplasma in one or more samples). Ninety percent of mycoplasma-mapped reads aligned to ribosomal RNA. This was unexpected given 37% of contaminated series used poly(A)-selection for mRNA enrichment. Lastly, we examined the relationship between mycoplasma contamination and host gene expression in a single cell RNA-seq dataset and found 61 host genes (P < 0.001) were significantly associated with mycoplasma-mapped read counts. In all, this study suggests mycoplasma contamination is still prevalent today and poses substantial risk to research quality. PMID:25712092

Development and Evaluation of Reproductive and Developmental Toxicity Tests for Assessing the Hazards of Environmental Contaminants

DTIC Science & Technology

1997-08-01

AL/EQ-TR-1997-0050 DEVELOPMENT AND EVALUATION OF REPRODUCTIVE AND DEVELOPMENT TOXICITY TESTS FOR ASSESSING THE HAZARDS OF ENVIRONMENTAL...SUBTITLE Development and Evaluation of Reproductive and Developmental Toxicity Tests for Assessing the Hazards of Environmental Contaminants 6...pd in testing toxicity in surface waters, ground waters and H- ™t™j£J^^^M hazard assessment when used in conjunction in sediments. FETAX can be usea

Human Health Risks Assessment Associated with Polychlorinated Biphenyls (PCBs) in Soil from Different Contaminated Areas of Mexico.

PubMed

Pérez-Maldonado, Iván N; Ochoa Martínez, Ángeles C; Ruíz-Vera, Tania; Orta-García, Sandra T; Varela-Silva, José A

2017-09-01

Recent studies have documented environmental contamination by PCBs in soil from different areas in Mexico (industrial, mining, and urban sites). However, the real significance of that soil contamination has not been established. Therefore, the aim of this study was to perform a human health risk assessment (Monte Carlos simulation) to evaluate the probable toxic effects of soils contaminated with PCBs on children in four sites in Mexico. A high non-carcinogenic risk (total nHQ = 1.1E+01; if nHQ ≥1, hazardous health effects cannot be ruled out) was found in Alpuyeca, Morelos, Mexico. Moreover, the total CR (cancer risk) found in Alpuyeca, Morelos is of concern (total CR = 5.1E-03), being that a cut-point of 1.0E-06 has been suggested as a safe level for cancer risk. Taking into consideration the data shown in this research, we conclude that a strategy to protect human health is necessary for the assessed sites.

Assessment of Heavy Metals Contamination in Reclaimed Mine Soil and their Accumulation and Distribution in Eucalyptus Hybrid.

PubMed

Maiti, Subodh Kumar; Rana, Vivek

2017-01-01

The metal contamination in reclaimed mine soil (RMS) of Jharia coal field, Dhanbad (India) using various contamination indices and their accumulation in tissues of Eucalyptus hybrid were assessed. In RMS, metal concentrations were found higher (202%-533%) than control soil (CS) with major contribution of Co and Mn followed by Zn, Cu and Pb. Principal component analysis (PCA) of metals present in RMS was carried out to assess their origin in RMS. The contamination factor (CF) values in RMS indicated moderate to very high level of pollution (ranged between 2.02 and 5.33). Higher accumulation of Pb in barks (three times), Zn in leaves (4.5 times), Mn in leaves (19 times), and Cu in roots (1.4 times) was found in trees growing on RMS than CS. The study concluded that different tree tissues accumulate varied concentration of heavy metals in RMS and thus for biomonitoring of metals, specific tissues has to be selected.

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.

A GIS-based vulnerability assessment of brine contamination to aquatic resources from oil and gas development in eastern Sheridan County, Montana

USGS Publications Warehouse

Preston, Todd M.; Chesley-Preston, Tara L.; Thamke, Joanna N.

2014-01-01

Water (brine) co-produced with oil in the Williston Basin is some of the most saline in the nation. The Prairie Pothole Region (PPR), characterized by glacial sediments and numerous wetlands, covers the northern and eastern portion of the Williston Basin. Sheridan County, Montana, lies within the PPR and has a documented history of brine contamination. Surface water and shallow groundwater in the PPR are saline and sulfate dominated while the deeper brines are much more saline and chloride dominated. A Contamination Index (CI), defined as the ratio of chloride concentration to specific conductance in a water sample, was developed by the Montana Bureau of Mines and Geology to delineate the magnitude of brine contamination in Sheridan County. Values > 0.035 indicate contamination. Recently, the U.S. Geological Survey completed a county level geographic information system (GIS)-based vulnerability assessment of brine contamination to aquatic resources in the PPR of the Williston Basin based on the age and density of oil wells, number of wetlands, and stream length per county. To validate and better define this assessment, a similar approach was applied in eastern Sheridan County at a greater level of detail (the 2.59 km2 Public Land Survey System section grid) and included surficial geology. Vulnerability assessment scores were calculated for the 780 modeled sections and these scores were divided into ten equal interval bins representing similar probabilities of contamination. Two surface water and two groundwater samples were collected from the section with the greatest acreage of Federal land in each bin. Nineteen of the forty water samples, and at least one water sample from seven of the ten selected sections, had CI values indicating contamination. Additionally, CI values generally increased with increasing vulnerability assessment score, with a stronger correlation for groundwater samples (R2 = 0.78) than surface water samples (R2 = 0.53).

Distribution of Arsenic and Risk Assessment of Activities on Soccer Pitches Irrigated with Arsenic-Contaminated Water.

PubMed

Martínez-Villegas, Nadia; Hernández, Abraham; Meza-Figueroa, Diana; Sen Gupta, Bhaskar

2018-05-24

The aim of this research was to estimate the risk of human exposure to arsenic due to sporting activities in a private soccer club in Mexico, where arsenic-contaminated water was regularly used for irrigation. For this purpose, the total concentration in the topsoil was considered for risk assessment. This was accomplished through three main objectives: (1) measuring arsenic concentrations in irrigation water and irrigated soils, (2) determining arsenic spatial distribution in shallow soils with Geographical Information Systems (GIS) using geostatistical analysis, and (3) collecting field and survey data to develop a risk assessment calculation for soccer activities in the soccer club. The results showed that the average arsenic concentrations in shallow soils (138.1 mg/kg) were 6.2 times higher than the Mexican threshold for domestic soils (22 mg/kg). Furthermore, dermal contact between exposed users and contaminated soils accounted for a maximum carcinogenic risk value of 1.8 × 10 −5 , which is one order of magnitude higher than the recommended risk value, while arsenic concentrations in the irrigation water were higher (6 mg/L) than the WHO’s permissible threshold in drinking water, explaining the contamination of soils after irrigation. To the best of our knowledge, this is the first risk study regarding dermal contact with arsenic following regular grass irrigation with contaminated water in soccer pitches.

Proposal and application of a regional methodology of comparative risk assessment for potentially contaminated sites.

PubMed

Marzocchini, Manrico; Tatàno, Fabio; Moretti, Michela Simona; Antinori, Caterina; Orilisi, Stefano

2018-06-05

A possible approach for determining soil and groundwater quality criteria for contaminated sites is the comparative risk assessment. Originating from but not limited to Italian interest in a decentralised (regional) implementation of comparative risk assessment, this paper first addresses the proposal of an original methodology called CORIAN REG-M , which was created with initial attention to the context of potentially contaminated sites in the Marche Region (Central Italy). To deepen the technical-scientific knowledge and applicability of the comparative risk assessment, the following characteristics of the CORIAN REG-M methodology appear to be relevant: the simplified but logical assumption of three categories of factors (source and transfer/transport of potential contamination, and impacted receptors) within each exposure pathway; the adaptation to quality and quantity of data that are available or derivable at the given scale of concern; the attention to a reliable but unsophisticated modelling; the achievement of a conceptual linkage to the absolute risk assessment approach; and the potential for easy updating and/or refining of the methodology. Further, the application of the CORIAN REG-M methodology to some case-study sites located in the Marche Region indicated the following: a positive correlation can be expected between air and direct contact pathway scores, as well as between individual pathway scores and the overall site scores based on a root-mean-square algorithm; the exposure pathway, which presents the highest variability of scores, tends to be dominant at sites with the highest computed overall site scores; and the adoption of a root-mean-square algorithm can be expected to emphasise the overall site scoring.

Quantitative assessment of historical coastal landfill contamination using in-situ field portable XRF (FPXRF)

NASA Astrophysics Data System (ADS)

O'Shea, Francis; Spencer, Kate; Brasington, James

2014-05-01

Historically, waste was deposited on low value, easily accessible coastal land (e.g. marsh land). Within England and Wales alone, there are over 5000 historical landfills situated within coastal areas at risk of flooding at a 1 in 100 year return period (Environment Agency, 2012). Historical sites were constructed prior to relevant legislation, and have no basal or side wall engineering, and the waste constituents are mostly unknown. In theory, contaminant concentrations should be reduced through natural attenuation as the leachate plume migrates through surrounding fine-grained inter-tidal sediments before reaching receptor waters. However, erosion resulting from rising sea level and increased storm intensity may re-distribute these sediments and release associated contaminants into the estuarine and coastal environment. The diffuse discharge from these sites has not been quantified and this presents a problem for those landfill managers who are required to complete EIAs. An earlier detailed field campaign at Newlands landfill site, on the Thames Estuary, UK identified a sub-surface (~2m depth) contaminant plume extending c. 20 m from the landfill boundary into surrounding fine-grained saltmarsh sediments. These saltmarsh sediments are risk of being eroded releasing their contaminant load to the Thames Estuary. The aims of this work were to; 1) assess whether this plume is representative of other historical landfills with similar characteristics and 2) to develop a rapid screening methodology using field portable XRF that could be used to identify potential risk of other coastal landfill sites. GIS was used to select landfill sites of similar age, hydrological regime and sedimentary setting in the UK, for comparison. Collection of sediment samples and analysis by ICP OES is expensive and time-consuming, therefore cores were extracted and analysed with a Niton Goldd XRF in-situ. Contaminant data were available immediately and the sampling strategy could be adapted

MOLFLUX analysis of the SSF electrical power system contamination

NASA Technical Reports Server (NTRS)

Cognion, Rita L.

1991-01-01

The external induced contamination of Space Station Freedom's electrical power system surfaces is assessed using a molecular flow evaluation code, MOLFLUX. Outgassing rates are compared to available experimental data, and deposition to the midregion of both the solar array and the photovoltaic power module thermal control system radiator is calculated using a constant sticking coefficient. An estimate of annual deposition to the solar array due to outgassing is found to be 10 percent of the Space Station Freedom program requirement for maximum allowable deposition, while annual deposition to the radiator is approximately equal to the requirement.

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...

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.

Dismantling of the PETRA glove box: tritium contamination and inventory assessment

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

Wagner, R.

2015-03-15

The PETRA facility is the first installation in which experiments with tritium were carried out at the Tritium Laboratory Karlsruhe. After completion of two main experimental programs, the decommissioning of PETRA was initiated with the aim to reuse the glove box and its main still valuable components. A decommissioning plan was engaged to: -) identify the source of tritium release in the glove box, -) clarify the status of the main components, -) assess residual tritium inventories, and -) de-tritiate the components to be disposed of as waste. Several analytical techniques - calorimetry on small solid samples, wipe test followedmore » by liquid scintillation counting for surface contamination assessment, gas chromatography on gaseous samples - were deployed and cross-checked to assess the remaining tritium inventories and initiate the decommissioning process. The methodology and the main outcomes of the numerous different tritium measurements are presented and discussed. (authors)« less

Evaluation of the Reference Envelope Approach for Assessing Toxicity in Contaminated Surficial Urban Freshwater Sediments

EPA Science Inventory

The reference envelope (RE) has been proposed as an alternative approach to assess sediment toxicity to overcome limitations imposed by the use of control sediments including differences in non-contaminant characteristics and low statistical power when many test sediments are com...

Assessment of soil-gas and soil contamination at the Old Metal Workshop Hog Farm Area, Fort Gordon, Georgia, 2009-2010

USGS Publications Warehouse

Caldwell, Andral W.; Falls, W. Fred; Guimaraes, Wladmir B.; Ratliff, W. Hagan; Wellborn, John B.; Landmeyer, James E.

2011-01-01

Soil gas and soil were assessed for contaminants at the Old Metal Workshop Hog Farm Area at Fort Gordon, Georgia, from October 2009 to September 2010. The assessment included delineating organic contaminants present in soil-gas and inorganic contaminants present in soil samples collected from the area estimated to be the Old Metal Workshop Hog Farm Area. This assessment was conducted to provide environmental contamination data to Fort Gordon personnel pursuant to requirements for the Resource Conservation and Recovery Act Part B Hazardous Waste Permit process. All soil-gas samplers contained total petroleum hydrocarbons above the method detection level. The highest total petroleum hydrocarbon mass detected was 121.32 micrograms in a soil-gas sampler from the western corner of the Old Metal Workshop Hog Farm Area along Sawmill Road. The highest undecane mass detected was 73.28 micrograms at the same location as the highest total petroleum hydrocarbon mass. Some soil-gas samplers detected toluene mass greater than the method detection level of 0.02 microgram; the highest detection of toluene mass was 0.07 microgram. Some soil-gas samplers were installed in areas of high-contaminant mass to assess for explosives and chemical agents. Explosives or chemical agents were not detected above their respective method detection levels for all soil-gas samplers installed. Inorganic concentrations in five soil samples collected did not exceed regional screening levels established by the U.S. Environmental Protection Agency. Barium concentrations, however, were up to eight times higher than the background concentrations reported in similar Coastal Plain sediments of South Carolina.

Assessment of radiation exposure from cesium-137 contaminated roads for epidemiological studies in Seoul, Korea

PubMed Central

Lee, Yun-Keun; Ju, Young-Su; Lee, Won Jin; Hwang, Seung Sik; Yim, Sang-Hyuk; Yoo, Sang-Chul; Lee, Jieon; Choi, Kyung-Hwa; Burm, Eunae; Ha, Mina

2015-01-01

Objectives We aimed to assess the radiation exposure for epidemiologic investigation in residents exposed to radiation from roads that were accidentally found to be contaminated with radioactive cesium-137 (137Cs) in Seoul. Methods Using information regarding the frequency and duration of passing via the 137Cs contaminated roads or residing/working near the roads from the questionnaires that were obtained from 8875 residents and the measured radiation doses reported by the Nuclear Safety and Security Commission, we calculated the total cumulative dose of radiation exposure for each person. Results Sixty-three percent of the residents who responded to the questionnaire were considered as ever-exposed and 1% of them had a total cumulative dose of more than 10 mSv. The mean (minimum, maximum) duration of radiation exposure was 4.75 years (0.08, 11.98) and the geometric mean (minimum, maximum) of the total cumulative dose was 0.049 mSv (<0.001, 35.35) in the exposed. Conclusions An individual exposure assessment was performed for an epidemiological study to estimate the health risk among residents living in the vicinity of 137Cs contaminated roads. The average exposure dose in the exposed people was less than 5% of the current guideline. PMID:26184047

Assessment of Adoption Gaps in Management of Aflatoxin Contamination of Groundnut ("Arachis Hypogaea" L.)

ERIC Educational Resources Information Center

Kumar, G. D. S.; Popat, M. N.

2010-01-01

One of the major impediments for diversification of groundnut ("Arachis Hypogaea" L.) as food crop is aflatoxin contamination. The study was conducted with an objective to assess the adoption gaps in aflatoxin management practices of groundnut (AMPG) and the farmer's characteristics influencing these gaps. The study used an expost-facto…

Assessing the effects of legacy contaminants on egg and ...

EPA Pesticide Factsheets

Great Lakes Areas of Concern (AOCs) are affected by many stressors, some of which are environmental contaminants including PCBs, PBDEs, persistent organochlorine pesticides, dioxins, benzenes, and other chemicals. These toxicants can accumulate in aquatic biota and ultimately transfer to insectivorous birds that use the aquatic areas within AOCs. We used a relatively new multistate survival modeling approach to examine the relationship between avian egg and nestling survival and 11 contaminant concentrations in representative eggs of Tree Swallows (Tachycineta bicolor) nestling at reference (n=10) and contaminated sites (n=59) within 27 AOCs around the Great Lakes. A total of 1,303 nests and 7,752 eggs were included in the modeling effort. Our analyses controlled for other common sources of variation in egg survival, including female age, date within season, year, and both site and AOC. Site, date within year, year, and female age all proved to be important variables in explaining egg survival. Among environmental contaminants, we found few associations between egg and nestling failure and contaminant concentration in representative eggs. Total dioxin furan toxicity equivalents (TDFTEQ) was significantly positively associated with egg failure, but significantly negatively associated with nestling death. Across the full dose response for this contaminant, empirically observed values of TDFTEQ were concentrated at the low end, with only a few values at the

A national-scale assessment of micro-organic contaminants in groundwater of England and Wales.

PubMed

Manamsa, Katya; Crane, Emily; Stuart, Marianne; Talbot, John; Lapworth, Dan; Hart, Alwyn

2016-10-15

A large variety of micro-organic (MO) compounds is used in huge quantities for a range of purposes (e.g. manufacturing, food production, healthcare) and is now being frequently detected in the aquatic environment. Interest in the occurrence of MO contaminants in the terrestrial and aquatic environments continues to grow, as well as in their environmental fate and potential toxicity. However, the contamination of groundwater resources by MOs has a limited evidence base compared to other freshwater resources. Of particular concern are newly 'emerging contaminants' such as pharmaceuticals and lifestyle compounds, particularly those with potential endocrine disrupting properties. While groundwater often has a high degree of protection from pollution due to physical, chemical and biological attenuation processes in the subsurface compared to surface aquatic environments, trace concentrations of a large range of compounds are still detected in groundwater and in some cases may persist for decades due to the long residence times of groundwater systems. This study provides the first national-scale assessment of micro-organic compounds in groundwater in England and Wales. A large set of monitoring data was analysed to determine the relative occurrence and detected concentrations of different groups of compounds and to determine relationships with land-use, aquifer type and groundwater vulnerability. MOs detected including emerging compounds such as caffeine, DEET, bisphenol A, anti-microbial agents and pharmaceuticals as well as a range of legacy contaminants including chlorinated solvents and THMs, petroleum hydrocarbons, pesticides and other industrial compounds. There are clear differences in MOs between land-use types, particularly for urban-industrial and natural land-use. Temporal trends of MO occurrence are assessed but establishing long-term trends is not yet possible. Copyright © 2016 British Geological Survey, NERC. Published by Elsevier B.V. All rights reserved.

Source-term development for a contaminant plume for use by multimedia risk assessment models

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

Whelan, Gene; McDonald, John P.; Taira, Randal Y.

1999-12-01

Multimedia modelers from the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Energy (DOE) are collaborating to conduct a comprehensive and quantitative benchmarking analysis of four intermedia models: DOE's Multimedia Environmental Pollutant Assessment System (MEPAS), EPA's MMSOILS, EPA's PRESTO, and DOE's RESidual RADioactivity (RESRAD). These models represent typical analytically, semi-analytically, and empirically based tools that are utilized in human risk and endangerment assessments for use at installations containing radioactive and/or hazardous contaminants. Although the benchmarking exercise traditionally emphasizes the application and comparison of these models, the establishment of a Conceptual Site Model (CSM) should be viewed with equalmore » importance. This paper reviews an approach for developing a CSM of an existing, real-world, Sr-90 plume at DOE's Hanford installation in Richland, Washington, for use in a multimedia-based benchmarking exercise bet ween MEPAS, MMSOILS, PRESTO, and RESRAD. In an unconventional move for analytically based modeling, the benchmarking exercise will begin with the plume as the source of contamination. The source and release mechanism are developed and described within the context of performing a preliminary risk assessment utilizing these analytical models. By beginning with the plume as the source term, this paper reviews a typical process and procedure an analyst would follow in developing a CSM for use in a preliminary assessment using this class of analytical tool.« less

Modeling aeolian transport in response to succession, disturbance and future climate: Dynamic long-term risk assessment for contaminant redistribution

USGS Publications Warehouse

Breshears, D.D.; Kirchner, T.B.; Whicker, J.J.; Field, J.P.; Allen, Craig D.

2012-01-01

Aeolian sediment transport is a fundamental process redistributing sediment, nutrients, and contaminants in dryland ecosystems. Over time frames of centuries or longer, horizontal sediment fluxes and associated rates of contaminant transport are likely to be influenced by succession, disturbances, and changes in climate, yet models of horizontal sediment transport that account for these fundamental factors are lacking, precluding in large part accurate assessment of human health risks associated with persistent soil-bound contaminants. We present a simple model based on empirical measurements of horizontal sediment transport (predominantly saltation) to predict potential contaminant transport rates for recently disturbed sites such as a landfill cover. Omnidirectional transport is estimated within vegetation that changes using a simple Markov model that simulates successional trajectory and considers three types of short-term disturbances (surface fire, crown fire, and drought-induced plant mortality) under current and projected climates. The model results highlight that movement of contaminated soil is sensitive to vegetation dynamics and increases substantially (e.g., > fivefold) when disturbance and/or future climate are considered. The time-dependent responses in horizontal sediment fluxes and associated contaminant fluxes were sensitive to variability in the timing of disturbance, with longer intervals between disturbance allowing woody plants to become dominant and crown fire and drought abruptly reducing woody plant cover. Our results, which have direct implications for contaminant transport and landfill management in the specific context of our assessment, also have general relevance because they highlight the need to more fully account for vegetation dynamics, disturbance, and changing climate in aeolian process studies.

Assessing the potential for rhizoremediation of PCB contaminated soils in northern regions using native species

PubMed Central

Slater, Heather; Gouin, Todd; Leigh, Mary Beth

2011-01-01

Rhizosphere bioremediation of polychlorinated biphenyls (PCBs) offers a potentially inexpensive approach to remediating contaminated soils that is particularly attractive in remote regions including the Arctic. We assessed the abilities of two tree species native to Alaska, Salix alaxensis (felt-leaf willow) and Picea glauca (white spruce), to promote microbial biodegradation of PCBs via the release of phytochemicals upon fine root death. Crushed fine roots, biphenyl (PCB analogue) or salicylate (willow secondary compound) were added to microcosms containing soil spiked with PCBs and resultant PCB disappearance, soil toxicity and microbial community changes were examined. After 180 d, soil treated with willow root crushates showed a significantly greater PCB loss than untreated soils for some PCB congeners, including the toxic congeners, PCB 77, 105 and 169, and showed a similar PCB loss pattern (in both extent of degradation and congeners degraded) to biphenyl-treated microcosms. Neither P. glauca (white spruce) roots nor salicylate enhanced PCB loss, indicating that biostimulation is plant species specific and was not mediated by salicylate. Soil toxicity assessed using the Microtox bioassay indicated that the willow treatment resulted in a less toxic soil environment. Molecular microbial community analyses indicated that biphenyl and salicylate promoted shifts in microbial community structure and composition that differed distinctly from each other and from the crushed root treatments. The biphenyl utilizing bacterium, Cupriavidus spp. was isolated from the soil. The findings suggest that S. alaxensis may be an effective plant for rhizoremediation by altering microbial community structure, enhancing the loss of some PCB congeners and reducing the toxicity of the soil environment. PMID:21596420

Environmental assessment of aromatic hydrocarbons-contaminated sediments of the Mexican Salina Cuz Bay.

PubMed

González-Macías, C; Schifter, I; Lluch-Cota, D B; Méndez-Rodríguez, L; Hernández-Vázquez, S

2007-10-01

Concentrations of total aromatic hydrocarbons and extractable organic matter in the water column and sediment were determined in samples collected in the course of the last 20 years from the Salina Cruz Harbor, México, to assess the degree of organic contamination. In sediments, organic compounds accumulate in shallow areas mostly associated with extractable organic matter and fine fractions. Calculated geocumulation index and enrichment factors suggest that contamination could be derived from anthropogenic activities attributed to harbor and ship scrapping activities, as well as transboundary source. Concentration of total aromatic hydrocarbons (as chrysene equivalents) ranged from 0.01 to 534 microg l(-1) in water, and from 0.10 to 2,160 microg g(-1) in sediments. Total aromatic concentration of 5 microg g(-1) is proposed as background concentration.

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.

Assessment of organic contaminants in emissions from refuse-derived fuel combustion

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

Chrostowski, J.; Wait, D.; Kwong, E.

1985-09-01

Organic contaminants in emissions from refuse-derived fuel combustion were investigated in a 20-inch-diameter atmospheric fluidized-bed combustor. Combinations of coal/EcoFuel/MSW/toluene were burned inthe combustor with temperatures ranging from 1250 to 1550 degrees F. A Source Assessment Sampling System (SASS) was used to sample the stack gas; Level 1 methodology was used to analyze the organic-contaminant levels. Combustion efficiencies of 93 to 98 percent were achieved in the test burns. Combustion of the EcoFuel generated fewer organic emissions than combustion of coal at similar combustion temperatures. The fine particulate collected by the SASS train filter contained higher concentrations of extractable organics thanmore » the reactor fly ash and the SASS cyclone samples. Combustion of a toluene/EcoFuel mix generated a large number of benzene derivatives not seen in the combustion of pure EcoFuel. Polycyclic aromatic hydrocarbons were the dominant organic compounds contained in the XAD-2 resin extract from coal combustion. A number of different priority pollutants were identified in the samples collected.« less

A molecular epidemiological study of methicillin-resistant Staphylococci environmental contamination in railway stations and coach stations in Guangzhou of China.

PubMed

Lin, J L; Peng, Y; Ou, Q T; Lin, D X; Li, Y; Ye, X H; Zhou, J L; Yao, Z J

2017-02-01

Methicillin-resistant Staphylococcus aureus (MRSA) has caused a series of public health problems since it was first found in 1961. However, there are few research studies on the MRSA environmental contamination in railway stations and coach stations. Therefore, the aim of this study was to determine MRSA environmental contamination in public transport stations. Between December 2013 and January 2014, 380 surface samples from three railway stations (180) and four coach stations (200) in Guangzhou were collected to isolate and determine the prevalence and characteristics of Staphylococci strains. 39·21% of all samples were Staphylococci isolates, 1·58% of Staphylococci isolates were MRSA isolates, and 6·05% were methicillin-susceptible S. aureus. The proportion of multidrug resistant among 149 Staphylococci isolates was 75·84%. None of MRSA isolates was identified with the Panton-Valentine Leukocidin (PVL) genes, and one of them was identified with the qac gene. Four MRSA isolates were Staphylococcal Cassette Chromosome mec IVa, and the other two were nontypeable. Staphylococcus aureus isolates were classified into several sequence types (STs), and STs showed possible cross-transmissions of isolates from various sources. Methicillin-resistant Staphylococci contamination prevalence was high, and the environment of stations may be the vectors transmitting the Staphylococci to passengers. This is the first study to comprehensively report the prevalence, antibiotic resistance, and molecular characteristics of contamination of Staphylococci isolates in railway stations and coach stations of China. It will have great public health implications on infection control in community settings because of the serious hazard of Staphylococci, especially methicillin-resistant Staphylococci. Our findings have provided evidence for relevant departments to reduce the contamination of Staphylococci in environment of public transport stations. © 2016 The Society for Applied

Phytoremediation of dye contaminated soil by Leucaena leucocephala (subabul) seed and growth assessment of Vigna radiata in the remediated soil

PubMed Central

Jayanthy, V.; Geetha, R.; Rajendran, R.; Prabhavathi, P.; Karthik Sundaram, S.; Dinesh Kumar, S.; Santhanam, P.

2013-01-01

The present study was investigated for soil bioremediation through sababul plant biomass (Leucaena leucocephala). The soil contaminated with textile effluent was collected from Erode (chithode) area. Various physico-chemical characterizations like N, P, and K and electrical conductivity were assessed on both control and dye contaminated soils before and after remediation. Sababul (L. leucocephala) powder used as plant biomass for remediation was a tool for textile dye removal using basic synthetic dyes by column packing and eluting. The concentration of the dye eluted was compared with its original concentration of dye and were analyzed by using UV–vis spectrophotometer. Sababul plant biomass was analyzed for its physico-chemical properties and active compounds were detected by GC–MS, HPTLC and FTIR. Plant growth was assessed with green gram on the textile contaminated soil and sababul had the potential of adsorbing the dye as the contaminated soil and also check the growth of green gram. PMID:25183943

Direct simulation Monte Carlo prediction of on-orbit contaminant deposit levels for HALOE

NASA Technical Reports Server (NTRS)

Woronowicz, Michael S.; Rault, Didier F. G.

1994-01-01

A three-dimensional version of the direct simulation Monte Carlo method is adapted to assess the contamination environment surrounding a highly detailed model of the Upper Atmosphere Research Satellite. Emphasis is placed on simulating a realistic, worst-case set of flow field and surface conditions and geometric orientations for the satellite in order to estimate an upper limit for the cumulative level of volatile organic molecular deposits at the aperture of the Halogen Occultation Experiment. A detailed description of the adaptation of this solution method to the study of the satellite's environment is also presented. Results pertaining to the satellite's environment are presented regarding contaminant cloud structure, cloud composition, and statistics of simulated molecules impinging on the target surface, along with data related to code performance. Using procedures developed in standard contamination analyses, along with many worst-case assumptions, the cumulative upper-limit level of volatile organic deposits on HALOE's aperture over the instrument's 35-month nominal data collection period is estimated at about 13,350 A.

Assessment of soil-gas and soil contamination at the Patterson Anti-Tank Range, Fort Gordon, Georgia, 2009-2010

USGS Publications Warehouse

Caldwell, Andral W.; Falls, W. Fred; Guimaraes, Wladmir B.; Ratliff, W. Hagan; Wellborn, John B.; Landmeyer, James E.

2011-01-01

Soil gas and soil were assessed for contaminants at the Patterson Anti-Tank Range at Fort Gordon, Georgia, from October 2009 to September 2010. The assessment included identifying and delineating organic contaminants present in soil-gas samplers from the area estimated to be the Patterson Anti-Tank Range and in the hyporheic zone and floodplain of Brier Creek. This assessment was conducted to provide environmental contamination data to Fort Gordon personnel pursuant to requirements for the Resource Conservation and Recovery Act Part B Hazardous Waste Permit process. Soil-gas samplers in the hyporheic zone and floodplain of Brier Creek contained total petroleum hydrocarbons, benzene, octane, and pentadecane concentrations above method detection levels. All soil-gas samplers within the boundary of the Patterson Anti-Tank Range contained total petroleum hydrocarbons above the method detection level. The highest total petroleum hydrocarbon mass detected was 147.09 micrograms in a soil-gas sampler located near the middle of the site and near the remnants of a manmade earthen mound and trench. The highest toluene mass detected was 1.04 micrograms and was located in the center of the Patterson Anti-Tank Range and coincides with a manmade earthen mound. Some soil-gas samplers installed detected undecane masses greater than the method detection level of 0.04 microgram, with the highest detection of soil-gas undecane mass of 58.64 micrograms collected along the southern boundary of the site. Some soil-gas samplers were installed in areas of high-contaminant mass to assess for explosives and chemical agents. Explosives or chemical agents were not detected above their respective method detection levels for all soil-gas samplers installed.

Assessment of Soil-Gas and Soil Contamination at the Former Military Police Range, Fort Gordon, Georgia, 2009-2010

USGS Publications Warehouse

Falls, W. Fred; Caldwell, Andral W.; Guimaraes, Wladmir B.; Ratliff, W. Hagan; Wellborn, John B.; Landmeyer, James E.

2011-01-01

Soil gas and soil were assessed for organic and inorganic contaminants at the former military police range at Fort Gordon, Georgia, from May to September 2010. The assessment evaluated organic contaminants in soil-gas samplers and inorganic contaminants in soil samples. This assessment was conducted to provide environmental contamination data to Fort Gordon pursuant to requirements of the Resource Conservation and Recovery Act Part B Hazardous Waste Permit process. Soil-gas samplers deployed and collected from May 20 to 24, 2010, identified masses above method detection level for total petroleum hydrocarbons, gasoline-related and diesel-related compounds, and chloroform. Most of these detections were in the southwestern quarter of the study area and adjacent to the road on the eastern boundary of the site. Nine of the 11 chloroform detections were in the southern half of the study area. One soil-gas sampler deployed adjacent to the road on the southern boundary of the site detected a mass of tetrachloroethene greater than, but close to, the method detection level of 0.02 microgram. For soil-gas samplers deployed and collected from September 15 to 22, 2010, none of the selected organic compounds classified as chemical agents and explosives were detected above method detection levels. Inorganic concentrations in the five soil samples collected at the site did not exceed the U.S. Environmental Protection Agency regional screening levels for industrial soil and were at or below background levels for similar rocks and strata in South Carolina.

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.

To-date spacecraft applications and demonstration testing results, and future product development for new molecular adsorber technologies

NASA Technical Reports Server (NTRS)

Thomson, Shaun; Hansen, Patricia; Straka, Sharon; Chen, Philip; Triolo, Jack; Bettini, Ron; Carosso, Paolo; Carosso, Nancy

1997-01-01

The use of molecular adsorbers, in order to aid in the reduction of the spacecraft contamination levels, is discussed. Molecular adsorbers are characterized by an extremely large surface area, molecularly-porous substructure, and processing charged sites capable of retaining molecular contaminant species. Molecular adsorbers were applied on two Hubble Space Telescope servicing missions, as well as on the tropical rainfall measuring mission. The use of molecular adsorbers carries the potential for low cost, easy fabrication and integration of reliable means for reducing the contamination level around spacecraft.

Assessment of potential indigenous plant species for the phytoremediation of arsenic-contaminated areas of Bangladesh.

PubMed

Mahmud, Rezwanul; Inoue, Naoto; Kasajima, Shin-Ya; Shaheen, Riffat

2008-01-01

Soil and water contaminated with arsenic (As) pose a major environmental and human health problem in Bangladesh. Phytoremediation, a plant-based technology, may provide an economically viable solution for remediating the As-polluted sites. The use of indigenous plants with a high tolerance and accumulation capacity for As may be a very convenient approach for phytoremediation. To assess the potential of native plant species for phytoremediation, plant and soil samples were collected from four As-contaminated (groundwater) districts in Bangladesh. The main criteria used for selecting plants for phytoremediation were high bioconcentration factors (BCFs) and translocation factors (TFs) of As. From the results of a screening of 49 plant species belonging to 29 families, only one species of fern (Dryopteris filix-mas), three herbs (Blumea lacera, Mikania cordata, and Ageratum conyzoides), and two shrubs (Clerodendrum trichotomum and Ricinus communis) were found to be suitable for phytoremediation. Arsenic bioconcentration and translocation factors > 1 suggest that these plants are As-tolerant accumulators with potential use in phytoextraction. Three floating plants (Eichhornia crassipes, Spirodela polyrhiza, and Azolla pinnata) and a common wetland weed (Monochoria vaginalis) also showed high BCF and TF values; therefore, these plants may be promising candidates for cleaningup As-contaminated surface water and wetland areas. The BCF of Oryza sativa, obtained from As-contaminated districts was > 1, which highlights possible food-chain transfer issues for As-contaminated areas in Bangladesh.

Assessment of Soil-Gas, Surface-Water, and Soil Contamination at the Installation Railhead, Fort Gordon, Georgia, 2008-2009

USGS Publications Warehouse

Landmeyer, James E.; Harrelson, Larry G.; Ratliff, W. Hagan; Wellborn, John B.

2010-01-01

The U.S. Geological Survey, in cooperation with the U.S. Department of the Army Environmental and Natural Resources Management Office of the U.S. Army Signal Center and Fort Gordon, assessed soil gas, surface water, and soil for contaminants at the Installation Railhead (IR) at Fort Gordon, Georgia, from October 2008 to September 2009. The assessment included delineation of organic contaminants present in soil-gas samples beneath the IR, and in a surface-water sample collected from an unnamed tributary to Marcum Branch in the western part of the IR. Inorganic contaminants were determined in a surface-water sample and in soil samples. This assessment was conducted to provide environmental contamination data to Fort Gordon personnel pursuant to requirements of the Resource Conservation and Recovery Act Part B Hazardous Waste Permit process. Soil-gas samples collected within a localized area on the western part of the IR contained total petroleum hydrocarbons; benzene, toluene, ethylbenzene, and total xylenes (referred to as BTEX); and naphthalene above the method detection level. These soil-gas samples were collected where buildings had previously stood. Soil-gas samples collected within a localized area contained perchloroethylene (PCE). These samples were collected where buildings 2410 and 2405 had been. Chloroform and toluene were detected in a surface-water sample collected from an unnamed tributary to Marcum Branch but at concentrations below the National Primary Drinking Water Standard maximum contaminant level (MCL) for each compound. Iron was detected in the surface-water sample at 686 micrograms per liter (ug/L) and exceeded the National Secondary Drinking Water Standard MCL for iron. Metal concentrations in composite soil samples collected at three locations from land surface to a depth of 6 inches did not exceed the U.S. Environmental Protection Agency Regional Screening Levels for industrial soil.

A GIS-based vulnerability assessment of brine contamination to aquatic resources from oil and gas development in eastern Sheridan County, Montana.

PubMed

Preston, Todd M; Chesley-Preston, Tara L; Thamke, Joanna N

2014-02-15

Water (brine) co-produced with oil in the Williston Basin is some of the most saline in the nation. The Prairie Pothole Region (PPR), characterized by glacial sediments and numerous wetlands, covers the northern and eastern portion of the Williston Basin. Sheridan County, Montana, lies within the PPR and has a documented history of brine contamination. Surface water and shallow groundwater in the PPR are saline and sulfate dominated while the deeper brines are much more saline and chloride dominated. A Contamination Index (CI), defined as the ratio of chloride concentration to specific conductance in a water sample, was developed by the Montana Bureau of Mines and Geology to delineate the magnitude of brine contamination in Sheridan County. Values >0.035 indicate contamination. Recently, the U.S. Geological Survey completed a county level geographic information system (GIS)-based vulnerability assessment of brine contamination to aquatic resources in the PPR of the Williston Basin based on the age and density of oil wells, number of wetlands, and stream length per county. To validate and better define this assessment, a similar approach was applied in eastern Sheridan County at a greater level of detail (the 2.59 km(2) Public Land Survey System section grid) and included surficial geology. Vulnerability assessment scores were calculated for the 780 modeled sections and these scores were divided into ten equal interval bins representing similar probabilities of contamination. Two surface water and two groundwater samples were collected from the section with the greatest acreage of Federal land in each bin. Nineteen of the forty water samples, and at least one water sample from seven of the ten selected sections, had CI values indicating contamination. Additionally, CI values generally increased with increasing vulnerability assessment score, with a stronger correlation for groundwater samples (R(2)=0.78) than surface water samples (R(2)=0.53). Copyright © 2013

Assessment of the Risk of Medium-Term Internal Contamination in Minamisoma City, Fukushima, Japan, after the Fukushima Dai-ichi Nuclear Accident

PubMed Central

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

2014-01-01

Background: 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. Objective: We investigated both the prevalence and level of internal contamination in residents of Minamisoma, and identified factors determining the risk and levels of contamination. Methods: 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. Results: 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. Conclusions: 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. Citation: Sugimoto A, Gilmour S, Tsubokura M, Nomura S, Kami M, Oikawa T, Kanazawa Y, Shibuya K. 2014. Assessment of the risk of medium-term internal contamination in Minamisoma City, Fukushima, Japan, after the Fukushima Dai-ichi Nuclear accident. Environ Health Perspect 122:587–593;�

Ecological Risk Assessment of Metals Contamination in the Sediments of Natural Urban Wetlands in Dry Tropical Climate.

PubMed

Rana, Vivek; Maiti, Subodh Kumar; Jagadevan, Sheeja

2016-09-01

The pollution load due to metal contamination in the sediments of urban wetlands (Dhanbad, India) due to illegal release of domestic and industrial wastewater was studied by using various geochemical indices, such as contamination factor (Cf), degree of contamination (Cd), modified degree of contamination (mCd), pollution load index (PLI) and geoaccumulation index (Igeo) for Cu, Co, Cd, Cr and Mn. Cluster analysis (CA) and Principal component analysis (PCA) of metals present in wetland sediments were carried out to assess their origin and relationship with each other. The Cf values for different metals in the wetlands under investigation indicated low to very high level of pollution (Cf ranged between 0.02 and 14.15) with highest Cf (14.15) for Cd. The wetland receiving both domestic and industrial wastewater had the highest values of Cd, mCd and PLI as 17.48, 3.49 and 1.03 respectively.

Risk assessment of petroleum-contaminated soil using soil enzyme activities and genotoxicity to Vicia faba.

PubMed

Ma, Jun; Shen, Jinglong; Liu, Qingxing; Fang, Fang; Cai, Hongsheng; Guo, Changhong

2014-05-01

Pollution caused by petroleum is one of the most serious problems worldwide. To better understand the toxic effects of petroleum-contaminated soil on the microflora and phytocommunity, we conducted a comprehensive field study on toxic effects of petroleum contaminated soil collected from the city of Daqing, an oil producing region of China. Urease, protease, invertase, and dehydrogenase activity were significantly reduced in microflora exposed to contaminated soils compared to the controls, whereas polyphenol oxidase activity was significantly increased (P < 0.05). Soil pH, electrical conductivity, and organic matter content were correlated with total petroleum hydrocarbons (TPHs) and a correlation (P < 0.01) existed between the C/N ratio and TPHs. Protease, invertase and catalase were correlated with TPHs. The Vicia faba micronucleus (MN) test, chromosome aberrant (CA) analyses, and the mitotic index (MI) were used to detect genotoxicity of water extracts of the soil. Petroleum-contaminated samples indicated serious genotoxicity to plants, including decreased index level of MI, increased frequency of MN and CA. The combination of enzyme activities and genotoxicity test via Vicia faba can be used as an important indicator for assessing the impact of TPH on soil ecosystem.

Laser Cutting Eliminates Nucleic Acid Cross-Contamination in Dried-Blood-Spot Processing

PubMed Central

Daza, Glenda; Chang, Ming; Coombs, Robert

2012-01-01

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. PMID:23052309

Payload/orbiter contamination control requirement study, volume 1, exhibit A

NASA Technical Reports Server (NTRS)

Bareiss, L. E.; Hooper, V. W.; Rantanen, R. O.; Ress, E. B.

1974-01-01

This study is to identify and quantify the expected molecular and particulate on orbit contaminant environment for selected shuttle payloads as a result of major spacelab and shuttle orbiter contaminant sources. This investigation reviews individual payload susceptibilities to contamination, identifies the combined induced environment, identifies the risk of spacelab/payload critical surface(s) degradation, and provides preliminary contamination recommendations. It also establishes limiting factors which may depend upon operational activities associated with the payloads, spacelab, and the shuttle orbiter interface or upon independent payload functional activities.

Assessment of BTEX-induced health risk under multiple uncertainties at a petroleum-contaminated site: An integrated fuzzy stochastic approach

NASA Astrophysics Data System (ADS)

Zhang, Xiaodong; Huang, Guo H.

2011-12-01

Groundwater pollution has gathered more and more attention in the past decades. Conducting an assessment of groundwater contamination risk is desired to provide sound bases for supporting risk-based management decisions. Therefore, the objective of this study is to develop an integrated fuzzy stochastic approach to evaluate risks of BTEX-contaminated groundwater under multiple uncertainties. It consists of an integrated interval fuzzy subsurface modeling system (IIFMS) and an integrated fuzzy second-order stochastic risk assessment (IFSOSRA) model. The IIFMS is developed based on factorial design, interval analysis, and fuzzy sets approach to predict contaminant concentrations under hybrid uncertainties. Two input parameters (longitudinal dispersivity and porosity) are considered to be uncertain with known fuzzy membership functions, and intrinsic permeability is considered to be an interval number with unknown distribution information. A factorial design is conducted to evaluate interactive effects of the three uncertain factors on the modeling outputs through the developed IIFMS. The IFSOSRA model can systematically quantify variability and uncertainty, as well as their hybrids, presented as fuzzy, stochastic and second-order stochastic parameters in health risk assessment. The developed approach haw been applied to the management of a real-world petroleum-contaminated site within a western Canada context. The results indicate that multiple uncertainties, under a combination of information with various data-quality levels, can be effectively addressed to provide supports in identifying proper remedial efforts. A unique contribution of this research is the development of an integrated fuzzy stochastic approach for handling various forms of uncertainties associated with simulation and risk assessment efforts.

Risk assessment of coccidostatics during feed cross-contamination: animal and human health aspects.

PubMed

Dorne, J L C M; Fernández-Cruz, M L; Bertelsen, U; Renshaw, D W; Peltonen, K; Anadon, A; Feil, A; Sanders, P; Wester, P; Fink-Gremmels, J

2013-08-01

Coccidiosis, an intestinal plasmodium infection, is a major infectious disease in poultry and rabbits. Eleven different coccidiostats are licensed in the EU for the prevention of coccidiosis in these animal species. According to their chemical nature and main biological activity, these compounds can be grouped as ionophoric (monensin, lasalocid sodium, salinomycin, narasin, maduramicin and semduramicin) or non-ionophoric (robenidine, decoquinate, nicarbazin, diclazuril, and halofuginone) substances. Coccidiostats are used as feed additives, mixed upon request into the compounded feed. During the technical process of commercial feed production, cross-contamination of feed batches can result in the exposure of non-target animals and induce adverse health effects in these animals due to a specific sensitivity of mammalian species as compared to poultry. Residue formation in edible tissues of non-target species may result in unexpected human exposure through the consumption of animal products. This review presents recent risk assessments performed by the Scientific Panel on Contaminants in the Food Chain (CONTAM) of the European Food Safety Authority (EFSA). The health risk to non-target species that would result from the consumption of cross-contaminated feed with coccidostats at levels of 2, 5 or 10% was found to be negligible for most animal species with the exception of salinomycin and monensin in horses because of the particular sensitivity for which toxicity may occur when cross-contamination exceeds 2% and 5% respectively. Kinetic data and tissue analyses showed that residues of coccidiostats may occur in the liver and eggs in some cases. However, the level of residues of each coccidiostat in edible animal tissues remained sufficiently low that the aggregate exposure of consumers would not exceed the established acceptable daily intake (ADI) of each coccidiostat. It could be concluded that technical cross-contamination of animal feeds would not be expected to

Risk assessment of coccidostatics during feed cross-contamination: Animal and human health aspects

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

Dorne, J.L.C.M., E-mail: jean-lou.dorne@efsa.europa.eu; Fernández-Cruz, M.L.; Bertelsen, U.

Coccidiosis, an intestinal plasmodium infection, is a major infectious disease in poultry and rabbits. Eleven different coccidiostats are licensed in the EU for the prevention of coccidiosis in these animal species. According to their chemical nature and main biological activity, these compounds can be grouped as ionophoric (monensin, lasalocid sodium, salinomycin, narasin, maduramicin and semduramicin) or non-ionophoric (robenidine, decoquinate, nicarbazin, diclazuril, and halofuginone) substances. Coccidiostats are used as feed additives, mixed upon request into the compounded feed. During the technical process of commercial feed production, cross-contamination of feed batches can result in the exposure of non-target animals and induce adversemore » health effects in these animals due to a specific sensitivity of mammalian species as compared to poultry. Residue formation in edible tissues of non-target species may result in unexpected human exposure through the consumption of animal products. This review presents recent risk assessments performed by the Scientific Panel on Contaminants in the Food Chain (CONTAM) of the European Food Safety Authority (EFSA). The health risk to non-target species that would result from the consumption of cross-contaminated feed with coccidostats at levels of 2, 5 or 10% was found to be negligible for most animal species with the exception of salinomycin and monensin in horses because of the particular sensitivity for which toxicity may occur when cross-contamination exceeds 2% and 5% respectively. Kinetic data and tissue analyses showed that residues of coccidiostats may occur in the liver and eggs in some cases. However, the level of residues of each coccidiostat in edible animal tissues remained sufficiently low that the aggregate exposure of consumers would not exceed the established acceptable daily intake (ADI) of each coccidiostat. It could be concluded that technical cross-contamination of animal feeds would not be

Development, evaluation, and application of sediment quality targets for assessing and managing contaminated sediments in Tampa Bay, Florida

USGS Publications Warehouse

MacDonald, D.D.; Carr, R.S.; Eckenrod, D.; Greening, H.; Grabe, S.; Ingersoll, C.G.; Janicki, S.; Janicki, T.; Lindskoog, R.A.; Long, E.R.; Pribble, R.; Sloane, G.; Smorong, D.E.

2004-01-01

Tampa Bay is a large, urban estuary that is located in west central Florida. Although water quality conditions represent an important concern in this estuary, information from numerous sources indicates that sediment contamination also has the potential to adversely affect aquatic organisms, aquatic-dependent wildlife, and human health. As such, protecting relatively uncontaminated areas of the bay from contamination and reducing the amount of toxic chemicals in contaminated sediments have been identified as high-priority sediment management objectives for Tampa Bay. To address concerns related to sediment contamination in the bay, an ecosystem-based framework for assessing and managing sediment quality conditions was developed that included identification of sediment quality issues and concerns, development of ecosystem goals and objectives, selection of ecosystem health indicators, establishment of metrics and targets for key indicators, and incorporation of key indicators, metrics, and targets into watershed management plans and decision-making processes. This paper describes the process that was used to select and evaluate numerical sediment quality targets (SQTs) for assessing and managing contaminated sediments. These SQTs included measures of sediment chemistry, whole-sediment and pore-water toxicity, and benthic invertebrate community structure. In addition, the paper describes how the SQTs were used to develop site-specific concentration-response models that describe how the frequency of adverse biological effects changes with increasing concentrations of chemicals of potential concern. Finally, a key application of the SQTs for defining sediment management areas is discussed.

Molecular Microbial Analyses of the Mars Exploration Rovers Assembly Facility

NASA Technical Reports Server (NTRS)

Venkateswaran, Kasthuri; LaDuc, Myron T.; Newcombe, David; Kempf, Michael J.; Koke, John. A.; Smoot, James C.; Smoot, Laura M.; Stahl, David A.

2004-01-01

During space exploration, the control of terrestrial microbes associated with robotic space vehicles intended to land on extraterrestrial solar system bodies is necessary to prevent forward contamination and maintain scientific integrity during the search for life. Microorganisms associated with the spacecraft assembly environment can be a source of contamination for the spacecraft. In this study, we have monitored the microbial burden of air samples of the Mars Exploration Rovers' assembly facility at the Kennedy Space Center utilizing complementary diagnostic tools. To estimate the microbial burden and identify potential contaminants in the assembly facility, several microbiological techniques were used including culturing, cloning and sequencing of 16S rRNA genes, DNA microarray analysis, and ATP assays to assess viable microorganisms. Culturing severely underestimated types and amounts of contamination since many of the microbes implicated by molecular analyses were not cultivable. In addition to the cultivation of Agrobacterium, Burkholderia and Bacillus species, the cloning approach retrieved 16s rDNA sequences of oligotrophs, symbionts, and y-proteobacteria members. DNA microarray analysis based on rational probe design and dissociation curves complemented existing molecular techniques and produced a highly parallel, high resolution analysis of contaminating microbial populations. For instance, strong hybridization signals to probes targeting the Bacillus species indicated that members of this species were present in the assembly area samples; however, differences in dissociation curves between perfect-match and air sample sequences showed that these samples harbored nucleotide polymorphisms. Vegetative cells of several isolates were resistant when subjected to treatments of UVC (254 nm) and vapor H202 (4 mg/L). This study further validates the significance of non-cultivable microbes in association with spacecraft assembly facilities, as our analyses have

[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.

Fate of a metal-resistant inoculum in contaminated and pristine soils assessed by denaturing gradient gel electrophoresis

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

Stephen, J.R.; Chang, Y.J.; MacNaughton, S.J.

Cesium, cadmium, cobalt, and strontium are four contaminants frequently found in soils at biotoxic levels. Introduction of certain nongenetically modified bacteria has been frequently suggested as a method for the immobilization of heavy metal contaminants in soil, thereby reducing runoff and bioavailability. In this study, the authors have used the polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE) to track the survival of the five bacterial species added to soil microcosms with and without the addition of a mixture of these metals. The PCR primers targeted conserved regions of the 165 rDNA molecular present in all bacteria. Themore » reaction products were shown to reflect the relative abundance of the bacteria both in mixtures of pure cultures and against a background of all the eubacterial species present in the soil following inoculation. Three of the species (Pseudomonas aeruginosa FRD-1, Shewanella putrifaciens 200, and Desulfovibrio vulgaris Hildenborough) decreased rapidly following inoculation into both soils. The proportion of Alcaligenes eutrophus CH34 remained at a constant level throughout the 8-week experiment in both soil treatments. Sphingomonas aromaticivorans B0695 showed toxic metal-dependent survival in that its relative abundance dropped rapidly in pristine soil but remained at approximately inoculation levels throughout the experiment in contaminated microcosms.« less

Long-term assessment of natural attenuation: statistical approach on soils with aged PAH contamination.

PubMed

Ouvrard, Stéphanie; Chenot, Elodie-Denise; Masfaraud, Jean-François; Schwartz, Christophe

2013-07-01

Natural attenuation processes valorization for PAH-contaminated soil remediation has gained increasing interest from site owners. A misunderstanding of this method and a small amount of data available does not encourage its development. However, monitored natural attenuation (MNA) offers a valuable, cheaper and environmentally friendly alternative to more classical options such as physico-chemical treatments (e.g., chemical oxidation, thermal desorption). The present work proposes the results obtained during a long-term natural attenuation assessment of historically contaminated industrial soils under real climatic conditions. This study was performed after a 10 year natural attenuation period on 60 off-ground lysimeters filled with contaminated soils from different former industrial sites (coking industry, manufactured gas plants) whose initial concentration of PAH varied between 380 and 2,077 mg kg(-1). The analysed parameters included leached water characterization, soil PAH concentrations, evaluation of vegetation cover quality and quantity. Results showed a good efficiency of the PAH dissipation and limited transfer of contaminants to the environment. It also highlighted the importance of the fine soil fractions in controlling PAH reactivity. PAH dissipation through water leaching was limited and did not present a significant risk for the environment. This PAH water concentration appeared however as a good indicator of overall dissipation rate, thereby illustrating the importance of pollutant availability in predicting its degradation potential.

Assessment of sediment contamination at Great Lakes Areas of Concern: the ARCS Program Toxicity-Chemistry Work Group strategy

USGS Publications Warehouse

Ross, P.E.; Burton, G.A.; Crecelius, E.A.; Filkins, J. C.; Giesy, J.P.; Ingersoll, C.G.; Landrum, P.F.; Mac, M.J.; Murphy, T.J.; Rathbun, J. E.; Smith, V. E.; Tatem, H. E.; Taylor, R.W.

1992-01-01

In response to a mandate in Section 118(c)(3) of the Water Quality Act of 1987, a program called Assessment and Remediation of Contaminated Sediments (ARCS) was established. Four technical work groups were formed. This paper details the research strategy of the Toxicity-Chemistry Work Group.The Work Group's general objectives are to develop survey methods and to map the degree of contamination and toxicity in bottom sediments at three study areas, which will serve as guidance for future surveys at other locations. A related objective is to use the data base that will be generated to calculate sediment quality concentrations by several methods. The information needed to achieve these goals will be collected in a series of field surveys at three areas: Saginaw Bay (MI), Grand Calumet River (IN), and Buffalo River (NY). Assessments of the extent of contamination and potential adverse effects of contaminants in sediment at each of these locations will be conducted by collecting samples for physical characterization, toxicity testing, mutagenicity testing, chemical analyses, and fish bioaccumulation assays. Fish populations will be assessed for tumors and external abnormalities, and benthic community structure will be analyzed. A mapping approach will use low-cost indicator parameters at a large number of stations, and will extrapolate by correlation from traditional chemical and biological studies at a smaller number of locations. Sediment toxicity testing includes elutriate, pore water and whole sediment bioassays in a three-tiered framework. In addition to the regular series of toxicity tests at primary mater stations, some stations are selected for a more extensive suite of tests.

Toxicity assessment of industrial chemicals and airborne contaminants: transition from in vivo to in vitro test methods: a review.

PubMed

Bakand, S; Winder, C; Khalil, C; Hayes, A

2005-12-01

Exposure to occupational and environmental contaminants is a major contributor to human health problems. Inhalation of gases, vapors, aerosols, and mixtures of these can cause a wide range of adverse health effects, ranging from simple irritation to systemic diseases. Despite significant achievements in the risk assessment of chemicals, the toxicological database, particularly for industrial chemicals, remains limited. Considering there are approximately 80,000 chemicals in commerce, and an extremely large number of chemical mixtures, in vivo testing of this large number is unachievable from both economical and practical perspectives. While in vitro methods are capable of rapidly providing toxicity information, regulatory agencies in general are still cautious about the replacement of whole-animal methods with new in vitro techniques. Although studying the toxic effects of inhaled chemicals is a complex subject, recent studies demonstrate that in vitro methods may have significant potential for assessing the toxicity of airborne contaminants. In this review, current toxicity test methods for risk evaluation of industrial chemicals and airborne contaminants are presented. To evaluate the potential applications of in vitro methods for studying respiratory toxicity, more recent models developed for toxicity testing of airborne contaminants are discussed.

Assessment of Molecular Modeling & Simulation

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

None

2002-01-03

This report reviews the development and applications of molecular and materials modeling in Europe and Japan in comparison to those in the United States. Topics covered include computational quantum chemistry, molecular simulations by molecular dynamics and Monte Carlo methods, mesoscale modeling of material domains, molecular-structure/macroscale property correlations like QSARs and QSPRs, and related information technologies like informatics and special-purpose molecular-modeling computers. The panel's findings include the following: The United States leads this field in many scientific areas. However, Canada has particular strengths in DFT methods and homogeneous catalysis; Europe in heterogeneous catalysis, mesoscale, and materials modeling; and Japan in materialsmore » modeling and special-purpose computing. Major government-industry initiatives are underway in Europe and Japan, notably in multi-scale materials modeling and in development of chemistry-capable ab-initio molecular dynamics codes.« less

On predicting contamination levels of HALOE optics aboard UARS using direct simulation Monte Carlo

NASA Technical Reports Server (NTRS)

Woronowicz, Michael S.; Rault, Didier F. G.

1993-01-01

A three-dimensional version of the direct simulation Monte Carlo method is adapted to assess the contamination environment surrounding a highly detailed model of the Upper Atmosphere Research Satellite. Emphasis is placed on simulating a realistic, worst-case set of flowfield and surface conditions and geometric orientations in order to estimate an upper limit for the cumulative level of volatile organic molecular deposits at the aperture of the Halogen Occultation Experiment. Problems resolving species outgassing and vent flux rates that varied over many orders of magnitude were handled using species weighting factors. Results relating to contaminant cloud structure, cloud composition, and statistics of simulated molecules impinging on the target surface are presented, along with data related to code performance. Using procedures developed in standard contamination analyses, the cumulative level of volatile organic deposits on HALOE's aperture over the instrument's 35-month nominal data collection period is estimated to be about 2700A.

An Induced Environment Contamination Monitor for the Space Shuttle

NASA Technical Reports Server (NTRS)

Miller, E. R. (Editor); Decher, R. (Editor)

1978-01-01

The Induced Environment Contamination Monitor (IECM), a set of ten instruments integrated into a self-contained unit and scheduled to fly on shuttle Orbital Flight Tests 1 through 6 and on Spacelabs 1 and 2, is described. The IECM is designed to measure the actual environment to determine whether the strict controls placed on the shuttle system have solved the contamination problem. Measurements are taken during prelaunch, ascent, on-orbit, descent, and postlanding. The on-orbit measurements are molecular return flux, background spectral intensity, molecular deposition, and optical surface effects. During the other mission phases dew point, humidity, aerosol content, and trace gas are measured as well as optical surface effects and molecular deposition. The IECM systems and thermal design are discussed. Preflight and ground operations are presented together with associated ground support equipment. Flight operations and data reduction plans are given.

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

USGS Publications Warehouse

Arihood, Leslie D.; Cohen, David A.

2006-01-01

The Safe Water Drinking Act of 1974 as amended in 1996 gave each State the responsibility of developing a Source-Water Assessment Plan (SWAP) that is designed to protect public-water supplies from contamination. Each SWAP must include three elements: (1) a delineation of the source-water protection area, (2) an inventory of potential sources of contaminants within the area, and (3) a determination of the susceptibility of the public-water supply to contamination from the inventoried sources. The Indiana Department of Environmental Management (IDEM) was responsible for preparing a SWAP for all public-water supplies in Indiana, including about 2,400 small public ground-water supplies that are designated transient, non-community (TNC) supplies. In cooperation with IDEM, the U.S. Geological Survey compiled information on conditions near the TNC supplies and helped IDEM complete source-water assessments for each TNC supply. The delineation of a source-water protection area (called the assessment area) for each TNC ground-water supply was defined by IDEM as a circular area enclosed by a 300-foot radius centered at the TNC supply well. Contaminants of concern (COCs) were defined by IDEM as any of the 90 contaminants for which the U.S. Environmental Protection Agency has established primary drinking-water standards. Two of these, nitrate as nitrogen and total coliform bacteria, are Indiana State-regulated contaminants for TNC water supplies. IDEM representatives identified potential point and nonpoint sources of COCs within the assessment area, and computer database retrievals were used to identify potential point sources of COCs in the area outside the assessment area. Two types of methods-subjective and subjective hybrid-were used in the SWAP to determine susceptibility to contamination. Subjective methods involve decisions based upon professional judgment, prior experience, and (or) the application of a fundamental understanding of processes without the collection and

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

NASA Technical Reports Server (NTRS)

Riley, B. R.

1986-01-01

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

Use of Ultrasonic Energy in Assessing Microbial Contamination on Surfaces

PubMed Central

Puleo, John R.; Favero, Martin S.; Petersen, Norman J.

1967-01-01

Ultrasonic tanks were evaluated for their ability to remove viable microorganisms from various surfaces for subsequent enumeration. Test surfaces were polished stainless steel, smooth glass, frosted glass, and electronic components. The position of contaminated surfaces in relation to the ultrasonic energy source, distance of the ultrasonic source from the test surfaces, and temperature of the rinse fluid were some of the factors which influenced recovery. Experimental systems included both naturally occurring microbial contamination and artificial contamination with spores of Bacillus subtilis var. niger. The results showed that ultrasonic energy was more reliable and efficient than mechanical agitation for recovering surface contaminants. Conditions which increased the number and percentage of microorganisms recovered by ultrasonic energy were: using a cold rinse fluid, placing the sample bottle on the bottom of the ultrasonic tank, and facing the contaminated surfaces toward the energy source. It was also demonstrated that ultrasonic energy could be effectively used for eluting microorganisms from cotton swabs. PMID:16349743

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

PubMed

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

2012-11-01

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

Space simulation ultimate pressure lowered two decades by removal of diffusion pump oil contaminants during operation

NASA Technical Reports Server (NTRS)

Buggele, A. E.

1973-01-01

The complex problem why large space simulation chambers do not realize the true ultimate vacuum was investigated. Some contaminating factors affecting diffusion pump performance have been identified and some advances in vacuum/distillation/fractionation technology have been achieved which resulted in a two decade or more lower ultimate pressure. Data are presented to show the overall or individual contaminating effect of commonly used phthalate ester plasticizers of 390 to 530 molecular weight on diffusion pump performance. Methods for removing contaminants from diffusion pump silicone oil during operation and reclaiming contaminated oil by high vacuum molecular distillation are described.

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

Assessment of Ecological Risk of Heavy Metal Contamination in Coastal Municipalities of Montenegro

PubMed Central

Mugoša, Boban; Đurović, Dijana; Nedović-Vuković, Mirjana; Barjaktarović-Labović, Snežana; Vrvić, Miroslav

2016-01-01

Assessment of heavy metal concentrations in the soil samples of urban parks and playgrounds is very important for the evaluation of potential risks for residents, especially children. Until recently, there has been very little data about urban parks pollution in Montenegro. To evaluate the sources of potential contamination and concentration of heavy metals, soil samples from coastal urban parks and kindergartens of Montenegro were collected. Based on the heavy metal concentrations, multivariate analysis combined with geochemical approaches showed that soil samples in coastal areas of Montenegro had mean Pb and Cd concentrations that were over two times higher than the background values, respectively. Based on principal component analysis (PCA), soil pollution with Pb, Cd, Cu, and Zn is contributed by anthropogenic sources. Results for Cr in the surface soils were primarily derived from natural sources. Calculation of different ecological contamination factors showed that Cd is the primary contribution to ecological risk index (RI) origins from anthropogenic, industry, and urbanization sources. This data provides evidence about soil pollution in coastal municipalities of Montenegro. Special attention should be paid to this problem in order to continue further research and to consider possible ways of remediation of the sites where contamination has been observed. PMID:27043601

Assessing the State of Contamination in a Historic Mining Town Using Sediment Chemistry.

PubMed

Gutiérrez, Mélida; Wu, Shuo-Sheng; Rodriguez, Jameelah R; Jones, Ashton D; Lockwood, Benjamin E

2016-05-01

The United States town of Aurora, Missouri, USA, stockpiled lead (Pb) and zinc (Zn) mining wastes from the early to mid-1900s in the form of chat piles. Clean-up actions were undertaken at intervals in subsequent years including land leveling and removal of chat. This study assessed the current state of contamination by identifying areas where metals are present at toxic levels. For this purpose, stream sediment samples (N = 100) were collected over a 9 × 12 km area in and around Aurora. Their content of cadmium (Cd), Pb, and Zn were measured, and concentration maps were generated using ArcGIS to categorize affected areas. Metal concentrations varied over a wide range of values with the overall highest values observed in the north-northeast part of Aurora where abundant chat piles had been present. Comparison between observed concentrations and sediment-quality guidelines put the contaminated areas mentioned are above-toxic levels for Cd, Pb and Zn. In contrast, levels in rural areas and the southern part of Aurora were at background levels, thus posing no threat to aquatic habitats. The fact that contamination is constrained to a relatively small area can be advantageously used to implement further remediation and, by doing so, to help protect the underlying karst aquifer.

Assessment of Ecological Risk of Heavy Metal Contamination in Coastal Municipalities of Montenegro.

PubMed

Mugoša, Boban; Đurović, Dijana; Nedović-Vuković, Mirjana; Barjaktarović-Labović, Snežana; Vrvić, Miroslav

2016-03-31

Assessment of heavy metal concentrations in the soil samples of urban parks and playgrounds is very important for the evaluation of potential risks for residents, especially children. Until recently, there has been very little data about urban parks pollution in Montenegro. To evaluate the sources of potential contamination and concentration of heavy metals, soil samples from coastal urban parks and kindergartens of Montenegro were collected. Based on the heavy metal concentrations, multivariate analysis combined with geochemical approaches showed that soil samples in coastal areas of Montenegro had mean Pb and Cd concentrations that were over two times higher than the background values, respectively. Based on principal component analysis (PCA), soil pollution with Pb, Cd, Cu, and Zn is contributed by anthropogenic sources. Results for Cr in the surface soils were primarily derived from natural sources. Calculation of different ecological contamination factors showed that Cd is the primary contribution to ecological risk index (RI) origins from anthropogenic, industry, and urbanization sources. This data provides evidence about soil pollution in coastal municipalities of Montenegro. Special attention should be paid to this problem in order to continue further research and to consider possible ways of remediation of the sites where contamination has been observed.

Risk Assessment of Heavy Metals in Abandoned Mine Lands as Signifcant Contamination Problem in Romania

NASA Astrophysics Data System (ADS)

Horvath, E.; Jordan, G.; Fugedi, U.; Bartha, A.; Kuti, L.; Heltai, G.; Kalmar, J.; Waldmann, I.; Napradean, I.; Damian, G.

2009-04-01

INTRODUCTION 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. Pollution by acid mine drainage (AMD) from ore and coal mining is the outstanding and most important source of mining-induced environmental pollution. Younger et al. (2002) estimates that watercourses polluted by coal mine drainage could be in the order of 2,000 to 3,000 km, and 1,000 to 1,500 km polluted by metal mine discharges for the EU 15 Member States (Younger et al. 2002). Significance of contamination risk posed by mining is also highlighted by mine accidents such as those in Baia Mare, Romania in 2002 and in Aznalcollar, Spain in 1999 (Jordan and D'Alessandro 2004). The new EU Mine Waste Directive (Directive 2006/21/EC) requires the risk-based inventory of abandoned mines in the EU. The cost-effective implementation of the inventory is especially demanding in countries with extensive historic mining and great number of abandoned mine sites, like Romania. The problem is further complicated in areas with trans-boundary effects. The objective of this investigation to carry out the risk-based contamination assessment of a mine site with possible trans-boundary effects in Romania. Assessment follows the source-pathway-receptor chain with a special attention to heavy metal leaching from waste dumps as sources and to transport modelling along surface water pathways. STUDY AREA In this paper the Baiut mine catchment located in the Gutai Mts., Romania, close to the Hungarian border is studied. The polymetallic deposites in the Tertiary Inner-Carpathian Volcanic Arc are exposed by a series of abandoned Zn and Pb mines first operated in the 14th century. Elevation in the high relief catchment ranges from 449m to 1044m. Geology is characterised by andesites hosting the ore deposits and paleogene sediments dominating at the

ASSESSMENT OF THE MICROBIAL POTENTIAL FOR NITRATE- ENHANCED BIOREMEDIATION OF A JP-4 FUEL-CONTAMINATED AQUIFER

EPA Science Inventory

A site that was contaminated with JP-4 jet fuel was characterized microbiologically to assess the feasibility of nitrate-enhanced bioremediation. The results of microcosm studies indicated that the mean pseudo zero-order rate constants for alkylbenzene biodegradation and NO3^...

Modeling Contamination Migration on the Chandra X-ray Observatory - II

NASA Technical Reports Server (NTRS)

O'Dell, Stephen L.; Swartz, Douglas A.; Tice, Neil W.; Plucinsky, Paul P.; Grant, Catherine E.; Marshall, Herman L.; Vikhlinin, Alexey A.; Tennant, Allyn F.

2013-01-01

During its first 14 years of operation, the cold (about -60C) optical blocking filter of the Advanced CCD Imaging Spectrometer (ACIS), aboard the Chandra X-ray Observatory, has accumulated a growing layer of molecular contamination that attenuates low-energy x rays. Over the past few years, the accumulation rate, spatial distribution, and composition have changed. This evolution has motivated further analysis of contamination migration within and near the ACIS cavity. To this end, the current study employs a higher-fidelity geometric model of the ACIS cavity, detailed thermal modeling based upon temperature data, and a refined model of the molecular transport.

In situ measurements of scattering from contaminated optics in the Vacuum Ultraviolet

NASA Astrophysics Data System (ADS)

Herren, Kenneth A.; Linton, Roger C.; Whitaker, Ann F.

1990-07-01

NASA's In Situ Contamination Effects Facility has been used to measure the time dependence of the angular reflectance from molecularly contaminated optical surfaces in the vacuum ultraviolet. The light scattering measurements are accomplished in situ on optical surfaces in real time during deposition of molecular contaminants. The measurements are taken using noncoherent VUV sources with the predominant wavelengths being the krypton resonance lines at 1236 and 1600 angstroms. Detection of the scattered light is accomplished using a set of three solar blind VUV photomultipliers. An in-plane VUV BRDF (bidirectional reflectance distribution function) experiment is described and details of the on-going program to characterize optical materials exposed to the space environment is reported.

In situ measurements of scattering from contaminated optics in the Vacuum Ultraviolet

NASA Technical Reports Server (NTRS)

Herren, Kenneth A.; Linton, Roger C.; Whitaker, Ann F.

1990-01-01

NASA's In Situ Contamination Effects Facility has been used to measure the time dependence of the angular reflectance from molecularly contaminated optical surfaces in the vacuum ultraviolet. The light scattering measurements are accomplished in situ on optical surfaces in real time during deposition of molecular contaminants. The measurements are taken using noncoherent VUV sources with the predominant wavelengths being the krypton resonance lines at 1236 and 1600 angstroms. Detection of the scattered light is accomplished using a set of three solar blind VUV photomultipliers. An in-plane VUV BRDF (bidirectional reflectance distribution function) experiment is described and details of the on-going program to characterize optical materials exposed to the space environment is reported.

CONTAMINATION OF FISH IN STREAMS OF THE MID-ATLANTIC REGION: AN APPROACH TO REGIONAL INDICATOR SELECTION AND WILDLIFE ASSESSMENT

EPA Science Inventory

The extent of contamination of fish in the Mid-Atlantic Region was evaluated as part of the U.S. Environmental Protection Agency's Monitoring and Assessment Program's regional assessment in 1993 through 1994. Fish assemblages from wadeable streams were dominated by small, short-...

Evaluation of Legionella Air Contamination in Healthcare Facilities by Different Sampling Methods: An Italian Multicenter Study.

PubMed

Montagna, Maria Teresa; De Giglio, Osvalda; Cristina, Maria Luisa; Napoli, Christian; Pacifico, Claudia; Agodi, Antonella; Baldovin, Tatjana; Casini, Beatrice; Coniglio, Maria Anna; D'Errico, Marcello Mario; Delia, Santi Antonino; Deriu, Maria Grazia; Guida, Marco; Laganà, Pasqualina; Liguori, Giorgio; Moro, Matteo; Mura, Ida; Pennino, Francesca; Privitera, Gaetano; Romano Spica, Vincenzo; Sembeni, Silvia; Spagnolo, Anna Maria; Tardivo, Stefano; Torre, Ida; Valeriani, Federica; Albertini, Roberto; Pasquarella, Cesira

2017-06-22

Healthcare facilities (HF) represent an at-risk environment for legionellosis transmission occurring after inhalation of contaminated aerosols. In general, the control of water is preferred to that of air because, to date, there are no standardized sampling protocols. Legionella air contamination was investigated in the bathrooms of 11 HF by active sampling (Surface Air System and Coriolis ® μ) and passive sampling using settling plates. During the 8-hour sampling, hot tap water was sampled three times. All air samples were evaluated using culture-based methods, whereas liquid samples collected using the Coriolis ® μ were also analyzed by real-time PCR. Legionella presence in the air and water was then compared by sequence-based typing (SBT) methods. Air contamination was found in four HF (36.4%) by at least one of the culturable methods. The culturable investigation by Coriolis ® μ did not yield Legionella in any enrolled HF. However, molecular investigation using Coriolis ® μ resulted in eight HF testing positive for Legionella in the air. Comparison of Legionella air and water contamination indicated that Legionella water concentration could be predictive of its presence in the air. Furthermore, a molecular study of 12 L. pneumophila strains confirmed a match between the Legionella strains from air and water samples by SBT for three out of four HF that tested positive for Legionella by at least one of the culturable methods. Overall, our study shows that Legionella air detection cannot replace water sampling because the absence of microorganisms from the air does not necessarily represent their absence from water; nevertheless, air sampling may provide useful information for risk assessment. The liquid impingement technique appears to have the greatest capacity for collecting airborne Legionella if combined with molecular investigations.

Evaluation of Legionella Air Contamination in Healthcare Facilities by Different Sampling Methods: An Italian Multicenter Study

PubMed Central

Montagna, Maria Teresa; De Giglio, Osvalda; Cristina, Maria Luisa; Napoli, Christian; Pacifico, Claudia; Agodi, Antonella; Baldovin, Tatjana; Casini, Beatrice; Coniglio, Maria Anna; D’Errico, Marcello Mario; Delia, Santi Antonino; Deriu, Maria Grazia; Guida, Marco; Laganà, Pasqualina; Liguori, Giorgio; Moro, Matteo; Mura, Ida; Pennino, Francesca; Privitera, Gaetano; Romano Spica, Vincenzo; Sembeni, Silvia; Spagnolo, Anna Maria; Tardivo, Stefano; Torre, Ida; Valeriani, Federica; Albertini, Roberto; Pasquarella, Cesira

2017-01-01

Healthcare facilities (HF) represent an at-risk environment for legionellosis transmission occurring after inhalation of contaminated aerosols. In general, the control of water is preferred to that of air because, to date, there are no standardized sampling protocols. Legionella air contamination was investigated in the bathrooms of 11 HF by active sampling (Surface Air System and Coriolis®μ) and passive sampling using settling plates. During the 8-hour sampling, hot tap water was sampled three times. All air samples were evaluated using culture-based methods, whereas liquid samples collected using the Coriolis®μ were also analyzed by real-time PCR. Legionella presence in the air and water was then compared by sequence-based typing (SBT) methods. Air contamination was found in four HF (36.4%) by at least one of the culturable methods. The culturable investigation by Coriolis®μ did not yield Legionella in any enrolled HF. However, molecular investigation using Coriolis®μ resulted in eight HF testing positive for Legionella in the air. Comparison of Legionella air and water contamination indicated that Legionella water concentration could be predictive of its presence in the air. Furthermore, a molecular study of 12 L. pneumophila strains confirmed a match between the Legionella strains from air and water samples by SBT for three out of four HF that tested positive for Legionella by at least one of the culturable methods. Overall, our study shows that Legionella air detection cannot replace water sampling because the absence of microorganisms from the air does not necessarily represent their absence from water; nevertheless, air sampling may provide useful information for risk assessment. The liquid impingement technique appears to have the greatest capacity for collecting airborne Legionella if combined with molecular investigations. PMID:28640202

GSFC Space Simulation Laboratory Contamination Philosophy: Efficient Space Simulation Chamber Cleaning Techniques

NASA Technical Reports Server (NTRS)

Roman, Juan A.; Stitt, George F.; Roman, Felix R.

1997-01-01

This paper will provide a general overview of the molecular contamination philosophy of the Space Simulation Test Engineering Section and how the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) space simulation laboratory controls and maintains the cleanliness of all its facilities, thereby, minimizing down time between tests. It will also briefly cover the proper selection and safety precautions needed when using some chemical solvents for wiping, washing, or spraying thermal shrouds when molecular contaminants increase to unacceptable background levels.

Assessment of PCDD/Fs levels in soil at a contaminated sawmill site in Sweden--a GIS and PCA approach to interpret the contamination pattern and distribution.

PubMed

Henriksson, S; Hagberg, J; Bäckström, M; Persson, I; Lindström, G

2013-09-01

Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo-p-furans (PCDD/Fs) were analysed in soil from a Swedish sawmill site where chlorophenols (CPs) had been used more than 40 years ago. The most contaminated area at the site was the preservation subarea where the PCDD/F WHO2005-TEQ level was 3450 times higher than the current Swedish guideline value of 200 ng TEQ/kg soil for land for industrial use. It was also shown that a fire which destroyed the sawmill might have affected the congener distribution at the concerned areas. To get a broader picture of the contamination both GIS (spatial interpolation analysis) and multivariate data analysis (PCA) were applied to visualize and compare PCDD/F levels as well as congener distributions at different areas at the site. It is shown that GIS and PCA are powerful tools in decisions on future investigations, risk assessments and remediation of contaminated sites. Copyright © 2013 Elsevier Ltd. All rights reserved.

Monitoring airborne molecular contamination: a quantitative and qualitative comparison of real-time and grab-sampling techniques

NASA Astrophysics Data System (ADS)

Shupp, Aaron M.; Rodier, Dan; Rowley, Steven

2007-03-01

Monitoring and controlling Airborne Molecular Contamination (AMC) has become essential in deep ultraviolet (DUV) photolithography for both optimizing yields and protecting tool optics. A variety of technologies have been employed for both real-time and grab-sample monitoring. Real-time monitoring has the advantage of quickly identifying "spikes" and upset conditions, while 2 - 24 hour plus grab sampling allows for extremely low detection limits by concentrating the mass of the target contaminant over a period of time. Employing a combination of both monitoring techniques affords the highest degree of control, lowest detection limits, and the most detailed data possible in terms of speciation. As happens with many technologies, there can be concern regarding the accuracy and agreement between real-time and grab-sample methods. This study utilizes side by side comparisons of two different real-time monitors operating in parallel with both liquid impingers and dry sorbent tubes to measure NIST traceable gas standards as well as real world samples. By measuring in parallel, a truly valid comparison is made between methods while verifying the results against a certified standard. The final outcome for this investigation is that a dry sorbent tube grab-sample technique produced results that agreed in terms of accuracy with NIST traceable standards as well as the two real-time techniques Ion Mobility Spectrometry (IMS) and Pulsed Fluorescence Detection (PFD) while a traditional liquid impinger technique showed discrepancies.

QUANTITATION OF MOLECULAR ENDPOINTS FOR THE DOSE-RESPONSE COMPONENT OF CANCER RISK ASSESSMENT

EPA Science Inventory

Cancer risk assessment involves the steps of hazard identification, dose-response assessment, exposure assessment and risk characterization. The rapid advances in the use of molecular biology approaches has had an impact on all four components, but the greatest overall current...

Monitored Natural Attenuation of Inorganic Contaminants in Ground Water Volume 1 – Technical Basis for Assessment

EPA Science Inventory

This document represents the first volume of a set of three volumes that address the technical basis and requirements for assessing the potential applicability of MNA as part of a ground-water remedy for plumes with non-radionuclide and/or radionuclide inorganic contaminants. Vo...

Baseline risk assessment of ground water contamination at the uranium mill tailings site near Durango, Colorado. Revision 1

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

NONE

1995-09-01

For the UMTRA Project site located near Durango, Colorado (the Durango site), the Surface Project cleanup occurred from 1986 to 1991. An evaluation was made to determine whether exposure to ground water contaminated by uranium processing could affect people`s health. Exposure could occur from drinking water pumped from a hypothetical well drilled in the contaminated ground water area. In addition, environmental risks may result if plants or animals are exposed to contaminated ground water, or surface water that has mixed with contaminated ground water. This risk assessment report is the first site-specific document prepared for the UMTRA Ground Water Projectmore » at the Durango site. The results of this report and further site characterization of the Durango site will be used to determine what is necessary to protect public health and the environment, and to comply with the EPA standards.« less

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

USGS Publications Warehouse

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

2013-01-01

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

The Wide Field/Planetary Camera 2 (WFPC-2) molecular adsorber

NASA Technical Reports Server (NTRS)

Barengoltz, Jack; Moore, Sonya; Soules, David; Voecks, Gerald

1995-01-01

A device has been developed at the Jet Propulsion Laboratory, California Institute of Technology, for the adsorption of contaminants inside a space instrument during flight. The molecular adsorber was developed for use on the Wide Field Planetary Camera 2, and it has been shown to perform at its design specifications in the WFPC-2. The basic principle of the molecular adsorber is a zeolite-coated ceramic honeycomb. The arrangement is efficient for adsorption and also provides the needed rigidity to retain the special zeolite coating during the launch vibrational environment. The adsorber, on other forms, is expected to be useful for all flight instruments sensitive to internal sources of contamination. Typically, some internal contamination is unavoidable. A common design solution is to increase the venting to the exterior. However, for truly sensitive instruments, the external contamination environment is more severe. The molecular adsorber acts as a one-way vent to solve this problem. Continued development is planned for this device.

Widespread occurrence and potential for biodegradation of bioactive contaminants in Congaree National Park, USA

USGS Publications Warehouse

Bradley, Paul M.; Battaglin, William A.; Clark, Jimmy M.; Henning, Frank; Hladik, Michelle L.; Iwanowicz, Luke R.; Journey, Celeste A.; Riley, Jeffrey W.; Romanok, Kristin

2017-01-01

Organic contaminants with designed molecular bioactivity, such as pesticides and pharmaceuticals, originate from human and agricultural sources, occur frequently in surface waters, and threaten the structure and function of aquatic and terrestrial ecosystems. Congaree National Park in South Carolina (USA) is a vulnerable park unit due to its location downstream of multiple urban and agricultural contaminant sources and its hydrologic setting, being composed almost entirely of floodplain and aquatic environments. Seventy-two water and sediment samples were collected from 16 sites in Congaree National Park during 2013 to 2015, and analyzed for 199 and 81 targeted organic contaminants, respectively. More than half of these water and sediment analytes were not detected or potentially had natural sources. Pharmaceutical contaminants were detected (49 total) frequently in water throughout Congaree National Park, with higher detection frequencies and concentrations at Congaree and Wateree River sites, downstream from major urban areas. Forty-seven organic wastewater indicator chemicals were detected in water, and 36 were detected in sediment, of which approximately half are distinctly anthropogenic. Endogenous sterols and hormones, which may originate from humans or wildlife, were detected in water and sediment samples throughout Congaree National Park, but synthetic hormones were detected only once, suggesting a comparatively low risk of adverse impacts. Assessment of the biodegradation potentials of 8 14C-radiolabeled model contaminants indicated poor potentials for some contaminants, particularly under anaerobic sediments conditions.

Community Engaged Cumulative Risk Assessment of Exposure to Inorganic Well Water Contaminants, Crow Reservation, Montana

PubMed Central

Doyle, John T.; Lefthand, Myra J.; Young, Sara L.; Kindness, Larry; Other Medicine, Roberta; Ford, Timothy E.; Dietrich, Eric; Parker, Albert E.; Hoover, Joseph H.; Camper, Anne K.

2018-01-01

An estimated 11 million people in the US have home wells with unsafe levels of hazardous metals and nitrate. The national scope of the health risk from consuming this water has not been assessed as home wells are largely unregulated and data on well water treatment and consumption are lacking. Here, we assessed health risks from consumption of contaminated well water on the Crow Reservation by conducting a community-engaged, cumulative risk assessment. Well water testing, surveys and interviews were used to collect data on contaminant concentrations, water treatment methods, well water consumption, and well and septic system protection and maintenance practices. Additive Hazard Index calculations show that the water in more than 39% of wells is unsafe due to uranium, manganese, nitrate, zinc and/or arsenic. Most families’ financial resources are limited, and 95% of participants do not employ water treatment technologies. Despite widespread high total dissolved solids, poor taste and odor, 80% of families consume their well water. Lack of environmental health literacy about well water safety, pre-existing health conditions and limited environmental enforcement also contribute to vulnerability. Ensuring access to safe drinking water and providing accompanying education are urgent public health priorities for Crow and other rural US families with low environmental health literacy and limited financial resources. PMID:29304032

Effects of Contamination Upon the Performance of X-Ray Telescopes

NASA Technical Reports Server (NTRS)

O'Dell, Stephen L.; Elsner, Ronald F.; Oosterbroek, Tim

2010-01-01

Particulate and molecular contamination can each impact the performance of x-ray telescope systems. Furthermore, any changes in the level of contamination between on-ground calibration and in-space operation can compromise the validity of the calibration. Thus, it is important to understand the sensitivity of telescope performance, especially the net effective area and the wings of the point spread function to contamination. Here, we quantify this sensitivity and discuss the flow-down of science requirements to contamination-control requirements. As an example, we apply this methodology to the International X-ray Observatory (IXO), currently under joint study by ESA, JAXA, and NASA.

Effects of contamination upon the performance of x-ray telescopes

NASA Astrophysics Data System (ADS)

O'Dell, Stephen L.; Elsner, Ronald F.; Oosterbroek, Tim

2010-07-01

Particulate and molecular contamination can each impact the performance of x-ray telescope systems. Furthermore, any changes in the level of contamination between on-ground calibration and in-space operation can compromise the validity of the calibration. Thus, it is important to understand the sensitivity of telescope performance---especially the net effective area and the wings of the point spread function---to contamination. Here, we quantify this sensitivity and discuss the flow-down of science requirements to contamination-control requirements. As an example, we apply this methodology to the International X-ray Observatory (IXO), currently under joint study by ESA, JAXA, and NASA.

Modeling Contamination Migration on the Chandra X-Ray Observatory - III

NASA Technical Reports Server (NTRS)

O'Dell, Stephen L.; Swartz, Douglas A.; Tice, Neil W.; Plucinsky, Paul P.; Grant, Catherine E.; Marshall, Herman L.; Vikhlinin, Alexy A.; Tennant, Allyn F.; Dahmer, Matthew T.

2015-01-01

During its first 16 years of operation, the cold (about -60 C) optical blocking filter of the Advanced CCD Imaging Spectrometer (ACIS), aboard the Chandra X-ray Observatory, has accumulated a growing layer of molecular contamination that attenuates low-energy x rays. Over the past few years, the accumulation rate, spatial distribution, and composition have changed. This evolution has motivated further analysis of contamination migration within and near the ACIS cavity, in part to evaluate potential bake-out scenarios intended to reduce the level of contamination. Keywords: X-ray astronomy, CCDs, contamination, modeling and simulation, spacecraft operations

Effects of the contamination environment on surfaces and materials

NASA Technical Reports Server (NTRS)

Maag, Carl R.

1989-01-01

In addition to the issues that have always existed, demands are being placed on space systems for increased contamination prevention/control. Optical surveillance sensors are required to detect low radiance targets. This increases the need for very low scatter surfaces in the optical system. Particulate contamination levels typically experienced in today's working environments/habits will most likely compromise these sensors. Contamination (molecular and particulate) can also affect the survivability of space sensors in both the natural and hostile space environments. The effects of di-octyl phthalate (DOP) on sensors are discussed.

Contamination control program for the Extreme Ultraviolet Explorer instruments

NASA Technical Reports Server (NTRS)

Ray, David C.; Malina, Roger F.; Welsh, Barry Y.; Austin, James D.; Teti, Bonnie Gray

1989-01-01

A contamination-control program has been instituted for the optical components of the EUV Explorer satellite, whose 80-900 A range performance is easily degraded by particulate and molecular contamination. Cleanliness requirements have been formulated for the design, fabrication, and test phases of these instruments; in addition, contamination-control steps have been taken which prominently include the isolation of sensitive components in a sealed optics cavity. Prelaunch monitoring systems encompass the use of quartz crystal microbalances, particle witness plates, direct flight hardware sampling, and optical witness sampling of EUV scattering and reflectivity.

The role of biomarkers to assess oil-contaminated sediment quality using toxicity tests with clams and crabs.

PubMed

Morales-Caselles, Carmen; Martín-Díaz, María Laura; Riba, Inmaculada; Sarasquete, Carmen; Delvalls, Tomás Angel

2008-06-01

A 28-d bioassay was conducted with two invertebrate species with different feeding habits, the clam Ruditapes philippinarum and the shore crab Carcinus maenas. The purpose of the present study was to assess the quality of sediments affected by oil spills in different areas of the Spanish coast. The organisms were exposed to environmental samples of oil-contaminated sediments during four weeks and, after the experiment, a suite of biomarkers of exposure was measured: The phase one detoxification system was assessed by ethoxyresorufin-O-deethylase (EROD) activity; glutathione-S-transferase (GST) is a phase-two detoxification enzyme but also is implicated in oxidative stress events; glutathione peroxidase (GPX), glutathione reductase (GR), and the ferric reducing ability of plasma (FRAP) assay were analyzed to determine the antioxidant activity of the tissues. The biomarker results were correlated with the chemical compounds bound to sediments (polycyclic aromatic hydrocarbons [PAHs], polychlorinated biphenyls [PCBs], Zn, Cd, Pb, Cu, Ni, Co, V) and a principal component analysis was carried out with the purpose of linking all the variables and to detect those contaminated sediments potentially harmful to the biota. Results showed induction of biomarkers in both invertebrate species and significant differences (p < 0.05; p < 0.01) were established among sediments affected by different spills. The use of the selected biomarkers together with the sediment chemical analysis assesses the bioavailability of contaminants and has proven to be a suitable tool to monitor the environmental quality of sediments affected by oil spills.

Shuttle Contamination And Experimentation: DoD Implications

NASA Astrophysics Data System (ADS)

Barnhart, B. J.; Baker, J. C.

1981-07-01

As the DOD makes the transition into the Shuttle era, experimenters are becoming more concerned about the environmental contamination of the Shuttle Orbiter. Their concern is that Shuttle contamination could prevent major planned experiments from obtaining required data, particularly sensitive infrared systems (e.g., Talon Gold, SIRE, STMP). The performance of optical experiments could be limited by the natural background, by light scattering and emissions from particulates and molecules, and by molecular absorption. Deposition and optical surface degradation may prove to be extensive problems, particularly for cryogenic optics. Other experiments such as communications and space environment tests may also be affected by deposition as well as electromagnetic interference. It has been known that the Shuttle's environment could cause contamination problems during water dumps, thruster firings, paint outgassing and other sources. Predictions have been made, but the contamination species and extent of these problems will not be known definitely until space measurements are made. This paper identifies the contamination types, sources, and their possible effect on particular types of space experiments. The paper also discusses NASA's plans for contamination measurements and the Space Test experiments which could contribute to early resolution of the contamination questions.

Shuttle Contamination And Experimentation: DoD Implications

NASA Astrophysics Data System (ADS)

Barnhart, B. J.; Baker, J. C.

1982-02-01

As the DOD makes the transition into the Shuttle era, experimenters are becoming more concerned about the environmental contamination of the Shuttle Orbiter. Their concern is that Shuttle contamination could prevent major planned experiments from obtaining required data, particularly sensitive infrared systems (e.g., Talon Gold, SIRE, STMP). The performance of optical experiments could be limited by the natural background, by light scattering and emissions from particulates and molecules, and by molecular absorption. Deposition and optical surface degradation may prove to be extensive problems, particularly for cryogenic optics. Other experiments such as communications and space environment tests may also be affected by deposition as well as electromagnetic interference. It has been known that the Shuttle's environment could cause contamination problems during water dumps, thruster firings, paint outgassing and other sources. Predictions have been made, but the contamination species and extent of these problems will not be known definitely until space measurements are made. This paper identifies the contamination types, sources, and their possible effect on particular types of space experiments. The paper also discusses NASA's plans for contamination measurements and the Space Test experiments which could contribute to early resolution of the contamination questions.

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.

PAMAM dendrimers and graphene: materials for removing aromatic contaminants from water.

PubMed

DeFever, Ryan S; Geitner, Nicholas K; Bhattacharya, Priyanka; Ding, Feng; Ke, Pu Chun; Sarupria, Sapna

2015-04-07

We present results from experiments and atomistic molecular dynamics simulations on the remediation of naphthalene by polyamidoamine (PAMAM) dendrimers and graphene oxide (GrO). Specifically, we investigate 3rd-6th generation (G3-G6) PAMAM dendrimers and GrO with different levels of oxidation. The work is motivated by the potential applications of these emerging nanomaterials in removing polycyclic aromatic hydrocarbon contaminants from water. Our experimental results indicate that GrO outperforms dendrimers in removing naphthalene from water. Molecular dynamics simulations suggest that the prominent factors driving naphthalene association to these seemingly disparate materials are similar. Interestingly, we find that cooperative interactions between the naphthalene molecules play a significant role in enhancing their association to the dendrimers and GrO. Our findings highlight that while selection of appropriate materials is important, the interactions between the contaminants themselves can also be important in governing the effectiveness of a given material. The combined use of experiments and molecular dynamics simulations allows us to comment on the possible factors resulting in better performance of GrO in removing polyaromatic contaminants from water.

Risk assessment of soils contaminated by mercury mining, Northern Spain.

PubMed

Ordóñez, A; Alvarez, R; Charlesworth, S; De Miguel, E; Loredo, J

2011-01-01

Analytical results of soil samples taken in three different mercury mining sites in Northern Spain are studied to assess the potential adverse health effects of the exposure to trace elements associated with the mining process. Doses contacted through ingestion and inhalation and the dose absorbed through the skin were calculated using USEPA's exposure parameters and the US Department of Energy's toxicity values. The results of the risk assessment indicate that the highest risk is associated with ingestion of soil particles and that the trace element of major concern is arsenic, the exposure to which results in a high cancer risk value for all the sites ranging from 3.3 × 10(-5) to 3.6 × 10(-3), well above the 1 × 10(-5) probability level deemed unacceptable by most regulatory agencies. Regarding non-cancer effects, exposure to polluted soils yields an aggregate hazard index above the threshold value of 1 for all three sites, with As and Hg as the main contributors. Risk assessment has proven to be a very useful tool to identify the contaminants and exposure pathways of most concern in the soils from metal mining sites, as well as to categorize them in terms of action priority to ensure fitness for use.

Comparison of Air Impaction and Electrostatic Dust Collector Sampling Methods to Assess Airborne Fungal Contamination in Public Buildings.

PubMed

Normand, Anne-Cécile; Ranque, Stéphane; Cassagne, Carole; Gaudart, Jean; Sallah, Kankoé; Charpin, Denis-André; Piarroux, Renaud

2016-03-01

Many ailments can be linked to exposure to indoor airborne fungus. However, obtaining a precise measurement of airborne fungal levels is complicated partly due to indoor air fluctuations and non-standardized techniques. Electrostatic dust collector (EDC) sampling devices have been used to measure a wide range of airborne analytes, including endotoxins, allergens, β-glucans, and microbial DNA in various indoor environments. In contrast, viable mold contamination has only been assessed in highly contaminated environments such as farms and archive buildings. This study aimed to assess the use of EDCs, compared with repeated air-impactor measurements, to assess airborne viable fungal flora in moderately contaminated indoor environments. Indoor airborne fungal flora was cultured from EDCs and daily air-impaction samples collected in an office building and a daycare center. The quantitative fungal measurements obtained using a single EDC significantly correlated with the cumulative measurement of nine daily air impactions. Both methods enabled the assessment of fungal exposure, although a few differences were observed between the detected fungal species and the relative quantity of each species. EDCs were also used over a 32-month period to monitor indoor airborne fungal flora in a hospital office building, which enabled us to assess the impact of outdoor events (e.g. ground excavations) on the fungal flora levels on the indoor environment. In conclusion, EDC-based measurements provided a relatively accurate profile of the viable airborne flora present during a sampling period. In particular, EDCs provided a more representative assessment of fungal levels compared with single air-impactor sampling. The EDC technique is also simpler than performing repetitive air-impaction measures over the course of several consecutive days. EDC is a versatile tool for collecting airborne samples and was efficient for measuring mold levels in indoor environments. © The Author 2015

Environmental management: Integrating ecological evaluation, remediation, restoration, natural resource damage assessment and long-term stewardship on contaminated lands

PubMed Central

Burger, Joanna

2014-01-01

Ecological evaluation is essential for remediation, restoration, and Natural Resource Damage Assessment (NRDA), and forms the basis for many management practices. These include determining status and trends of biological, physical, or chemical/radiological conditions, conducting environmental impact assessments, performing remedial actions should remediation fail, managing ecosystems and wildlife, and assessing the efficacy of remediation, restoration, and long-term stewardship. The objective of this paper is to explore the meanings of these assessments, examine the relationships among them, and suggest methods of integration that will move environmental management forward. While remediation, restoration, and NRDA, among others, are often conducted separately, it is important to integrate them for contaminated land where the risks to ecoreceptors (including humans) can be high, and the potential damage to functioning ecosystems great. Ecological evaluations can range from inventories of local plants and animals, determinations of reproductive success of particular species, levels of contaminants in organisms, kinds and levels of effects, and environmental impact assessments, to very formal ecological risk assessments for a chemical or other stressor. Such evaluations can range from the individual species to populations, communities, ecosystems or the landscape scale. Ecological evaluations serve as the basis for making decisions about the levels and kinds of remediation, the levels and kinds of restoration possible, and the degree and kinds of natural resource injuries that have occurred because of contamination. Many different disciplines are involved in ecological evaluation, including biologists, conservationists, foresters, restoration ecologists, ecological engineers, economists, hydrologist, and geologists. Since ecological evaluation forms the basis for so many different types of environmental management, it seems reasonable to integrate management options

Low molecular weight species in humic and fulvic fractions

USGS Publications Warehouse

Wilson, M.A.; Collin, P.J.; Malcolm, R.L.; Perdue, E. Michael; Cresswell, P.

1988-01-01

Fourier transform solution 1H nuclear magnetic resonance (NMR) spectrometry with homogated water peak irradiation is a useful method for detecting low molecular weight substances in humic extracts. Succinate, acetate, methanol, formate, lactate and some aryl methoxyl compounds have been detected in extracts from a wide range of sources. In view of the controversy over whether low molecular weight substances are contaminants in humic extracts introduced by the concentration procedure, we report that some of these materials are not contaminants since 1H-NMR can be used to follow their formation from higher molecular weight species. ?? 1988.

Assessments of aquifer sensitivity on Navajo Nation and adjacent lands and ground-water vulnerability to pesticide contamination on the Navajo Indian Irrigation Project, Arizona, New Mexico, and Utah

USGS Publications Warehouse

Blanchard, Paul J.

2002-01-01

The U.S. Environmental Protection Agency requested that the Navajo Nation conduct an assessment of aquifer sensitivity on Navajo Nation lands and an assessment of ground-water vulnerability to pesticide contamination on the Navajo Indian Irrigation Project. Navajo Nation lands include about 17,000 square miles in northeastern Arizona, northwestern New Mexico, and southeastern Utah. The Navajo Indian Irrigation Project in northwestern New Mexico is the largest area of agriculture on the Navajo Nation. The Navajo Indian Irrigation Project began operation in 1976; presently (2001) about 62,000 acres are available for irrigated agriculture. Numerous pesticides have been used on the Navajo Indian Irrigation Project during its operation. Aquifer sensitivity is defined by the U.S. Environmental Protection Agency as 'The relative ease with which a contaminant [pesticide] applied on or near a land surface can migrate to the aquifer of interest. Aquifer sensitivity is a function of the intrinsic characteristics of the geologic material in question, any underlying saturated materials, and the overlying unsaturated zone. Sensitivity is not dependent on agronomic practices or pesticide characteristics.' Ground-water vulnerability is defined by the U.S. Environmental Protection Agency as 'The relative ease with which a contaminant [pesticide] applied on or near a land surface can migrate to the aquifer of interest under a given set of agronomic management practices, pesticide characteristics, and aquifer sensitivity conditions.' The results of the aquifer sensitivity assessment on Navajo Nation and adjacent lands indicated relative sensitivity within the boundaries of the study area. About 22 percent of the study area was not an area of recharge to bedrock aquifers or an area of unconsolidated deposits and was thus assessed to have an insignificant potential for contamination. About 72 percent of the Navajo Nation study area was assessed to be in the categories of most potential

Molecular characterization of chicken infectious anemia virus from contaminated live-virus vaccines.

PubMed

Li, Yang; Hu, Yan; Cui, Shuai; Fu, Jiayuan; Wang, Yixin; Cui, Zhizhong; Fang, Lichun; Chang, Shuang; Zhao, Peng

2017-05-01

The aim of this study was to investigate possible causes of the pervasiveness of chicken infectious anemia virus (CIAV) infection in chickens in recent years in China. A total of 14 batches of live-virus vaccines were examined using PCR to detect CIAV contamination, of which only 2 samples (a Newcastle disease vaccine and a fowl pox vaccine) tested positive for CIAV. These Newcastle and fowl pox vaccines were then inoculated into 1-day-old specific-pathogen-free chickens. Serum samples were collected from chickens infected with the PCR-positive vaccines, and these tested positive for CIAV-specific antibodies as tested using ELISA. In addition, DNA samples isolated from the serum samples also tested positive by PCR. The results indicated that the samples were contaminated with CIAV and identified 2 exogenous CIAV strains, designated CIAV-N22 and CIAV-F10, in the respective samples. The full genome sequences of these novel CIAV strains were sequenced and analyzed. Phylogenetic tree analysis indicated that the CIAV-F10 strain might represent a recombinant viral strain arising from the parental CIAV strains JQ690762 and KJ728816. Overall, the results suggested that vaccination with CIAV-contaminated vaccines contributed to the prevalence and spread of CIAV infection in chickens. Furthermore, the CIAV contaminant was likely subsequently transmitted to commercial chickens through congenital transmission. Our findings therefore highlight the need for more extensive screening of live-virus vaccines for poultry in China to reduce the threat of contamination with exogenous viruses. © 2016 Poultry Science Association Inc.

Assessment of the contamination potentials of some foodborne bacteria in biofilms for food products.

PubMed

Adetunji, Victoria O; Adedeji, Adeyemi O; Kwaga, Jacob

2014-09-01

To assess biofilms formed by different bacterial strains on glass slides, and changes in biofilm mass and biofilm-associated cell populations after brief contacts between biofilms and either media agar or food products. Two Listeria monocytogenes and Escherichia coli (E. coli) strains and a single Staphylococcus aureus (S. aureus) strain were inoculated separately in tryptic soy broth containing glass coupons incubated for 24, 48 or 72 h at 37 °C. The biofilms formed by individual bacterial strains and biofilm-associated cell populations were determined. Biofilms were subsequently allowed to have brief contacts (1-3 times), through gentle touching, with either agar, meat or soft white cheese (2 cm(3)). Changes in biofilm mass on glass slides and cell populations embedded in biofilms were quantified. A nonpathogenic E. coli formed more biofilms than an E. coli O157:H7 strain. Biofilms formed by S. aureus and Listeria monocytogenes were essentially similar. The biofilm mass increased as incubation time increased within 48 h of incubation and was not positively correlated with cellulose production. Biofilm mass at 48 and 72 h of incubation was not significantly different. More frequent contacts with agar or foods did not remove more biofilms or biofilm-associated cells from glass slides. More S. aureus biofilms were removed followed by Listeria and E. coli biofilms. Mean contamination of agar or food models was 0.00 to 7.65 log CFU/cm(2). Greater contaminations in cell populations were observed with S. aureus and Listeria biofilms. The results provide a clearer assessment of contaminating potential of foods that comes in contact with them. Copyright © 2014 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

Assessment of Surface Water Contamination from Coalbed Methane Fracturing-Derived Volatile Contaminants in Sullivan County, Indiana, USA.

PubMed

Meszaros, Nicholas; Subedi, Bikram; Stamets, Tristan; Shifa, Naima

2017-09-01

There is a growing concern over the contamination of surface water and the associated environmental and public health consequences from the recent proliferation of hydraulic fracturing in the USA. Petroleum hydrocarbon-derived contaminants of concern [benzene, toluene, ethylbenzene, and xylenes (BTEX)] and various dissolved cations and anions were spatially determined in surface waters around 15 coalbed methane fracking wells in Sullivan County, IN, USA. At least one BTEX compound was detected in 69% of sampling sites (n = 13) and 23% of sampling sites were found to be contaminated with all of the BTEX compounds. Toluene was the most common BTEX compound detected across all sampling sites, both upstream and downstream from coalbed methane fracking wells. The average concentration of toluene at a reservoir and its outlet nearby the fracking wells was ~2× higher than other downstream sites. However, one of the upstream sites was found to be contaminated with BTEX at similar concentrations as in a reservoir site nearby the fracking well. Calcium (~60 ppm) and sulfates (~175 ppm) were the dominant cations and anions, respectively, in surface water around the fracking sites. This study represents the first report of BTEX contamination in surface water from coalbed methane hydraulic fracturing wells.

Orbiter/payload contamination control assessment support

NASA Technical Reports Server (NTRS)

Rantanen, R. O.; Strange, D. A.; Hetrick, M. A.

1978-01-01

The development and integration of 16 payload bay liner filters into the existing shuttle/payload contamination evaluation (SPACE) computer program is discussed as well as an initial mission profile model. As part of the mission profile model, a thermal conversion program, a temperature cycling routine, a flexible plot routine and a mission simulation of orbital flight test 3 are presented.

Assessment of metal contaminations leaching out from recycling plastic bottles upon treatments.

PubMed

Cheng, Xiaoliang; Shi, Honglan; Adams, Craig D; Ma, Yinfa

2010-08-01

Heavy metal contaminants in environment, especially in drinking water, are always of great concern due to their health impact. Due to the use of heavy metals as catalysts during plastic syntheses, particularly antimony, human exposure to metal release from plastic bottles has been a serious concern in recent years. The aim and scope of this study were to assess metal contaminations leaching out from a series of recycling plastic bottles upon treatments. In this study, leaching concentrations of 16 metal elements were determined in 21 different types of plastic bottles from five commercial brands, which were made of recycling materials ranging from no. 1 to no. 7. Several sets of experiments were conducted to study the factors that could potentially affect the metal elements leaching from plastic bottles, which include cooling with frozen water, heating with boiling water, microwave, incubating with low-pH water, outdoor sunlight irradiation, and in-car storage. Heating and microwave can lead to a noticeable increase of antimony leaching relative to the controls in bottle samples A to G, and some even reached to a higher level than the maximum contamination level (MCL) of the US Environmental Protection Agency (USEPA) regulations. Incubation with low-pH water, outdoor sunlight irradiation, and in-car storage had no significant effect on antimony leaching relative to controls in bottle samples A to G, and the levels of antimony leaching detected were below 6 ppb which is the MCL of USEPA regulations. Cooling had almost no effect on antimony leaching based on our results. For the other interested 15 metal elements (Al, V, Cr, Mn, Co, Ni, Cu, As, Se, Mo, Ag, Cd, Ba, Tl, Pb), no significant leaching was detected or the level was far below the MCL of USEPA regulations in all bottle samples in this study. In addition, washing procedure did contribute to the antimony leaching concentration for polyethylene terephthalate (PET) bottles. The difference of antimony leaching

Understanding the development of roots exposed to contaminants and the potential of plant-associated bacteria for optimization of growth

PubMed Central

Remans, Tony; Thijs, Sofie; Truyens, Sascha; Weyens, Nele; Schellingen, Kerim; Keunen, Els; Gielen, Heidi; Cuypers, Ann; Vangronsveld, Jaco

2012-01-01

Background and Scope Plant responses to the toxic effects of soil contaminants, such as excess metals or organic substances, have been studied mainly at physiological, biochemical and molecular levels, but the influence on root system architecture has received little attention. Nevertheless, the precise position, morphology and extent of roots can influence contaminant uptake. Here, data are discussed that aim to increase the molecular and ecological understanding of the influence of contaminants on root system architecture. Furthermore, the potential of plant-associated bacteria to influence root growth by their growth-promoting and stress-relieving capacities is explored. Methods Root growth parameters of Arabidopsis thaliana seedlings grown in vertical agar plates are quantified. Mutants are used in a reverse genetics approach to identify molecular components underlying quantitative changes in root architecture after exposure to excess cadmium, copper or zinc. Plant-associated bacteria are isolated from contaminated environments, genotypically and phenotypically characterized, and used to test plant root growth improvement in the presence of contaminants. Key Results The molecular determinants of primary root growth inhibition and effects on lateral root density by cadmium were identified. A vertical split-root system revealed local effects of cadmium and copper on root development. However, systemic effects of zinc exposure on root growth reduced both the avoidance of contaminated areas and colonization of non-contaminated areas. The potential for growth promotion and contaminant degradation of plant-associated bacteria was demonstrated by improved root growth of inoculated plants exposed to 2,4-di-nitro-toluene (DNT) or cadmium. Conclusions Knowledge concerning the specific influence of different contaminants on root system architecture and the molecular mechanisms by which this is achieved can be combined with the exploitation of plant-associated bacteria to

Understanding the development of roots exposed to contaminants and the potential of plant-associated bacteria for optimization of growth.

PubMed

Remans, Tony; Thijs, Sofie; Truyens, Sascha; Weyens, Nele; Schellingen, Kerim; Keunen, Els; Gielen, Heidi; Cuypers, Ann; Vangronsveld, Jaco

2012-07-01

Plant responses to the toxic effects of soil contaminants, such as excess metals or organic substances, have been studied mainly at physiological, biochemical and molecular levels, but the influence on root system architecture has received little attention. Nevertheless, the precise position, morphology and extent of roots can influence contaminant uptake. Here, data are discussed that aim to increase the molecular and ecological understanding of the influence of contaminants on root system architecture. Furthermore, the potential of plant-associated bacteria to influence root growth by their growth-promoting and stress-relieving capacities is explored. Root growth parameters of Arabidopsis thaliana seedlings grown in vertical agar plates are quantified. Mutants are used in a reverse genetics approach to identify molecular components underlying quantitative changes in root architecture after exposure to excess cadmium, copper or zinc. Plant-associated bacteria are isolated from contaminated environments, genotypically and phenotypically characterized, and used to test plant root growth improvement in the presence of contaminants. The molecular determinants of primary root growth inhibition and effects on lateral root density by cadmium were identified. A vertical split-root system revealed local effects of cadmium and copper on root development. However, systemic effects of zinc exposure on root growth reduced both the avoidance of contaminated areas and colonization of non-contaminated areas. The potential for growth promotion and contaminant degradation of plant-associated bacteria was demonstrated by improved root growth of inoculated plants exposed to 2,4-di-nitro-toluene (DNT) or cadmium. Knowledge concerning the specific influence of different contaminants on root system architecture and the molecular mechanisms by which this is achieved can be combined with the exploitation of plant-associated bacteria to influence root development and increase plant stress

Considerations for Developing a Dosimetry-Based Cumulative Risk Assessment Approach for Mixtures of Environmental Contaminants (Final Report)

EPA Science Inventory

EPA announced the availability of the final report, Considerations for Developing a Dosimetry-Based Cumulative Risk Assessment Approach for Mixtures of Environmental Contaminants. This report describes a process that can be used to determine the potential value of develop...

USING THE SEDIMENT QUALITY TRIAD (SQT) APPROACH TO ASSESS SEDIMENTARY CONTAMINATION IN THE ANACOSTIA RIVER, WASHINGTON

EPA Science Inventory

Using the Sediment Quality Triad (SQT) Approach to Assess Sedimentary Contamination in the Anacostia River, Washington, D.C. Velinsky, DJ*1, Ashley, JTF1,2, Pinkney, F.3, McGee, BL3 and Norberg-King, TJ.4 1Academy of Natural Sciences-PCER, Philadelphia, PA. 2Philadelphia Universi...

Environmental survey to assess viral contamination of air and surfaces in hospital settings.

PubMed

Carducci, A; Verani, M; Lombardi, R; Casini, B; Privitera, G

2011-03-01

The presence of pathogenic viruses in healthcare settings represents a serious risk for both staff and patients. Direct viral detection in the environment poses significant technical problems and the indirect indicators currently in use suffer from serious limitations. The aim of this study was to monitor surfaces and air in hospital settings to reveal the presence of hepatitis C virus, human adenovirus, norovirus, human rotavirus and torque teno virus by nucleic acid assays, in parallel with measurements of total bacterial count and haemoglobin presence. In total, 114 surface and 62 air samples were collected. Bacterial contamination was very low (<1 cfu/cm(2)) on surfaces, whereas the 'medium' detected value in air was 282 cfu/m(3). Overall, 19 (16.7%) surface samples tested positive for viral nucleic acids: one for norovirus, one for human adenovirus and 17 (14.9%) for torque teno virus (TTV). Only this latter virus was directly detected in 10 air samples (16.1%). Haemoglobin was found on two surfaces. No relationship was found between viral, biochemical or bacterial indicators. The data obtained confirm the difficulty of assessing viral contamination using bacterial indicators. The frequent detection of TTV suggests its possible use as an indicator for general viral contamination of the environment. Copyright © 2010 The Hospital Infection Society. Published by Elsevier Ltd. All rights reserved.

Molecular analysis of Aspergillus section Flavi isolated from Brazil nuts.

PubMed

Gonçalves, Juliana Soares; Ferracin, Lara Munique; Carneiro Vieira, Maria Lucia; Iamanaka, Beatriz Thie; Taniwaki, Marta Hiromi; Pelegrinelli Fungaro, Maria Helena

2012-04-01

Brazil nuts are an important export market in its main producing countries, including Brazil, Bolivia, and Peru. Approximately 30,000 tons of Brazil nuts are harvested each year. However, substantial nut contamination by Aspergillus section Flavi occurs with subsequent production of aflatoxins. In our study, Aspergillus section Flavi were isolated from Brazil nuts (Bertholletia excelsa), and identified by morphological and molecular means. We obtained 241 isolates from nut samples, 41% positive for aflatoxin production. Eighty-one isolates were selected for molecular investigation. Pairwise genetic distances among isolates and phylogenetic relationships were assessed. The following Aspergillus species were identified: A. flavus, A. caelatus, A. nomius, A. tamarii, A. bombycis, and A. arachidicola. Additionally, molecular profiles indicated a high level of nucleotide variation within β-tubulin and calmodulin gene sequences associated with high genetic divergence from RAPD data. Among the 81 isolates analyzed by molecular means, three of them were phylogenetically distinct from all other isolates representing the six species of section Flavi. A putative novel species was identified based on molecular profiles.

CULTURE-INDEPENDENT MOLECULAR METHODS FOR FECAL SOURCE IDENTIFICATION

EPA Science Inventory

Fecal contamination is widespread in the waterways of the United States. Both to correct the problem, and to estimate public health risk, it is necessary to identify the source of the contamination. Several culture-independent molecular methods for fecal source identification hav...

Gene transcription patterns in response to low level petroleum contaminants in Mytilus trossulus from field sites and harbors in southcentral Alaska

NASA Astrophysics Data System (ADS)

Bowen, Lizabeth; Miles, A. Keith; Ballachey, Brenda; Waters, Shannon; Bodkin, James; Lindeberg, Mandy; Esler, Daniel

2018-01-01

The 1989 Exxon Valdez oil spill damaged a wide range of natural resources, including intertidal communities, and post-spill studies demonstrated acute and chronic exposure and injury to an array of species. Standard toxicological methods to evaluate petroleum contaminants have assessed tissue burdens, with fewer assays providing indicators of health or physiology, particularly when contaminant levels are low and chronic. Marine mussels are a ubiquitous and crucial component of the nearshore environment, and new genomic technologies exist to quantify molecular responses of individual mussels to stimuli, including exposure to polycyclic aromatic hydrocarbons (PAHs). We used gene-based assays of exposure and physiological function to assess chronic oil contamination using the Pacific blue mussel, Mytilus trossulus. We developed a diagnostic gene transcription panel to investigate exposure to PAHs and other contaminants and its effects on mussel physiology and health. During 2012-2015, we analyzed mussels from five field sites in western Prince William Sound, Alaska, with varying oil histories from the 1989 Exxon Valdez oil spill, and from three boat harbors in the area. Gene transcription patterns of mussels from harbors were consistent with elevated exposure to PAHs or other contaminants, whereas transcription patterns of mussels sampled from shorelines in areas affected by the oil spill indicated no PAH exposure.

Gene transcription patterns in response to low level petroleum contaminants in Mytilus trossulus from field sites and harbors in southcentral Alaska

USGS Publications Warehouse

Bowen, Lizabeth; Miles, A. Keith; Ballachey, Brenda E.; Waters, Shannon C.; Bodkin, James L.; Lindeberg, Mandy; Esler, Daniel N.

2017-01-01

The 1989 Exxon Valdez oil spill damaged a wide range of natural resources, including intertidal communities, and post-spill studies demonstrated acute and chronic exposure and injury to an array of species. Standard toxicological methods to evaluate petroleum contaminants have assessed tissue burdens, with fewer assays providing indicators of health or physiology, particularly when contaminant levels are low and chronic. Marine mussels are a ubiquitous and crucial component of the nearshore environment, and new genomic technologies exist to quantify molecular responses of individual mussels to stimuli, including exposure to polycyclic aromatic hydrocarbons (PAHs). We used gene-based assays of exposure and physiological function to assess chronic oil contamination using the Pacific blue mussel, Mytilus trossulus. We developed a diagnostic gene transcription panel to investigate exposure to PAHs and other contaminants and its effects on mussel physiology and health. During 2012–2015, we analyzed mussels from five field sites in western Prince William Sound, Alaska, with varying oil histories from the 1989 Exxon Valdez oil spill, and from three boat harbors in the area. Gene transcription patterns of mussels from harbors were consistent with elevated exposure to PAHs or other contaminants, whereas transcription patterns of mussels sampled from shorelines in areas affected by the oil spill indicated no PAH exposure.

Materials SIG quantification and characterization of surface contaminants

NASA Technical Reports Server (NTRS)

Crutcher, E. Russ

1992-01-01

When LDEF entered orbit its cleanliness was approximately a MIL-STD-1246B Level 2000C. Its burden of contaminants included particles from every part of its history including a relatively small contribution from the shuttle bay itself. Although this satellite was far from what is normally considered clean in the aerospace industry, contaminating events in orbit and from processing after recovery were easily detected. The molecular contaminants carried into orbit were dwarfed by the heavy deposition of UV polymerized films from outgassing urethane paints and silicone based materials. Impacts by relatively small objects in orbit could create particulate contaminants that easily dominated the particle counts within a centimeter of the impact site. During the recovery activities LDEF was 'sprayed' with a liquid high in organics and water soluble salts. With reentry turbulence, vibration, and gravitational loading particulate contaminants were redistributed about LDEF and the shuttle bay.

Using Pre-Assessment and In-Class Questions to Change Student Understanding of Molecular Movements †

PubMed Central

Shi, J.; Knight, Jennifer K.; Chun, Hyonho; Guild, Nancy A.; Martin, Jennifer M.

2017-01-01

Understanding how different types of molecules move through cell membranes is a fundamental part of cell biology. To identify and address student misconceptions surrounding molecular movement through cell membranes, we surveyed student understanding on this topic using pre-class questions, in-class clicker questions, and subsequent exam questions in a large introductory biology course. Common misconceptions identified in student responses to the pre-class assessment questions were used to generate distractors for clicker questions. Two-tier diagnostic clicker questions were used to probe incoming common student misconceptions (first tier) and their reasoning (second tier). Two subsequent lectures with assessment clicker questions were used to help students construct a new framework to understand molecular movement through cell membranes. Comparison of pre-assessment and post-assessment (exam) performance showed dramatic improvement in students’ understanding of molecular movement: student answers to exam questions were 74.6% correct with correct reasoning while only 1.3% of the student answers were correct with correct reasoning on the pre-class assessment. Our results show that students’ conceptual understanding of molecular movement through cell membranes progressively increases through discussions of a series of clicker questions and suggest that this clicker-based teaching strategy was highly effective in correcting common student misconceptions on this topic. PMID:28512521

Bioavailability assessments following biochar and activated carbon amendment in DDT-contaminated soil.

PubMed

Denyes, Mackenzie J; Rutter, Allison; Zeeb, Barbara A

2016-02-01

The effects of 2.8% w/w granulated activated carbon (GAC) and two types of biochar (Burt's and BlueLeaf) on DDT bioavailability in soil (39 μg/g) were investigated using invertebrates (Eisenia fetida), plants (Cucurbita pepo spp. pepo) and a polyoxymethylene (POM) passive sampler method. Biochar significantly reduced DDT accumulation in E. fetida (49%) and showed no detrimental effects to invertebrate health. In contrast, addition of GAC caused significant toxic effects (invertebrate avoidance and decreased weight) and did not significantly reduce the accumulation of DDT into invertebrate tissue. None of the carbon amendments reduced plant uptake of DDT. Bioaccumulation of 4,4'DDT and 4,4'-DDE in plants (C. pepo spp. pepo) and invertebrates (E. fetida) was assessed using bioaccumulation factors (BAFs) and compared to predicted bioavailability using the freely-dissolved porewater obtained from a polyoxymethylene (POM) equilibrium biomimetic method. The bioavailable fraction predicted by the POM samplers correlated well with measured invertebrate uptake (<50% variability), but was different from plant root uptake by 134%. A literature review of C. pepo BAFs across DDT soil contamination levels and the inclusion of field data from a 2.5 μg/g DDT-contaminated site found that these plants exhibit a concentration threshold effect at [DDT](soil) > 10 μg/g. The results of these studies illustrate the importance of including plants in bioavailability studies as the use of carbon materials for in situ contaminant sorption moves from predominantly sediment to soil remediation technologies. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

NASA Astrophysics Data System (ADS)

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

2016-12-01

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

Assessing the potential for rhizoremediation of PCB contaminated soils in northern regions using native tree species.

PubMed

Slater, Heather; Gouin, Todd; Leigh, Mary Beth

2011-06-01

Rhizosphere bioremediation of polychlorinated biphenyls (PCBs) offers a potentially inexpensive approach to remediating contaminated soils that is particularly attractive in remote regions including the Arctic. We assessed the abilities of two tree species native to Alaska, Salix alaxensis (felt-leaf willow) and Picea glauca (white spruce), to promote microbial biodegradation of PCBs via the release of phytochemicals upon fine root death. Crushed fine roots, biphenyl (PCB analogue) or salicylate (willow secondary compound) were added to microcosms containing soil spiked with PCBs and resultant PCB disappearance, soil toxicity and microbial community changes were examined. After 180d, soil treated with willow root crushates showed a significantly greater PCB loss than untreated soils for some PCB congeners, including the toxic congeners, PCB 77, 105 and 169, and showed a similar PCB loss pattern (in both extent of degradation and congeners degraded) to biphenyl-treated microcosms. Neither P. glauca (white spruce) roots nor salicylate enhanced PCB loss, indicating that biostimulation is plant species specific and was not mediated by salicylate. Soil toxicity assessed using the Microtox bioassay indicated that the willow treatment resulted in a less toxic soil environment. Molecular microbial community analyses indicated that biphenyl and salicylate promoted shifts in microbial community structure and composition that differed distinctly from each other and from the crushed root treatments. The biphenyl utilizing bacterium, Cupriavidus spp. was isolated from the soil. The findings suggest that S. alaxensis may be an effective plant for rhizoremediation by altering microbial community structure, enhancing the loss of some PCB congeners and reducing the toxicity of the soil environment. Copyright © 2011 Elsevier Ltd. All rights reserved.

Bioaccessibility and Human Exposure Assessment of Cadmium and Arsenic in Pakchoi Genotypes Grown in Co-Contaminated Soils

PubMed Central

Wei, Yanyan; Zheng, Xiaoman; Shohag, Md. Jahidul Islam; Gu, Minghua

2017-01-01

In many countries cadmium (Cd) and arsenic (As) commonly coexist in soils contaminated by mining activities, and can easily enter the human body via consumption of leafy vegetables, like the popularly consumed pakchoi (Brassica chinensis L.), causing major health concerns. In the present study, bioaccessibility and human exposure of Cd and As were assessed in twenty genotypes of pakchoi cultured at two different levels of co-contamination to identify low health risk genotypes. The bioaccessibilities of Cd and As represent a fraction of the total metals content could be bioaccessible for human, in the present study, significant differences in pakchoi Cd and As bioaccessibility were observed among all tested genotypes and co-contaminated levels. Cd and As bioaccessibility of pakchoi were in the ranges of 24.0–87.6% and 20.1–82.5%, respectively, for in the high level co-contaminated soils, which was significantly higher than for low level co-contaminated soils with 7.9–71.8% for Cd bioaccessibility and 16.1–59.0% for As bioaccessibility. The values of bioaccessible established daily intakes (BEDI) and the total bioaccessible target hazard quotients (TBTHQ) of Cd and As were also considerably higher in high level co-contaminated soils than in low level co-contaminated soils. Two genotypes (Meiguanqinggengcai and Zhenqing60F1) contained relatively low concentrations and bioaccessible Cd and As and, their BEDI and TBTHQ for Cd and As ranged below the tolerable limits set by the FAO/WHO (BEDI of Cd < 0.83 μg kg−1 bw day−1, BEDI of As < 3 μg kg−1 bw day−1) and United States Environmental Protection Agency (TBTHQ for Cd and As < 1), this applied for both levels of co-contaminated soils for adults and children. Consequently, these findings suggest identification of safe genotypes in leafy vegetable with low health risk via genotypic screening and breeding methods could be a useful strategy to ensure the safety of food crops grown in those Cd and As co-contaminated

Bioaccessibility and Human Exposure Assessment of Cadmium and Arsenic in Pakchoi Genotypes Grown in Co-Contaminated Soils.

PubMed

Wei, Yanyan; Zheng, Xiaoman; Shohag, Md Jahidul Islam; Gu, Minghua

2017-08-29

In many countries cadmium (Cd) and arsenic (As) commonly coexist in soils contaminated by mining activities, and can easily enter the human body via consumption of leafy vegetables, like the popularly consumed pakchoi ( Brassica chinensis L.), causing major health concerns. In the present study, bioaccessibility and human exposure of Cd and As were assessed in twenty genotypes of pakchoi cultured at two different levels of co-contamination to identify low health risk genotypes. The bioaccessibilities of Cd and As represent a fraction of the total metals content could be bioaccessible for human, in the present study, significant differences in pakchoi Cd and As bioaccessibility were observed among all tested genotypes and co-contaminated levels. Cd and As bioaccessibility of pakchoi were in the ranges of 24.0-87.6% and 20.1-82.5%, respectively, for in the high level co-contaminated soils, which was significantly higher than for low level co-contaminated soils with 7.9-71.8% for Cd bioaccessibility and 16.1-59.0% for As bioaccessibility. The values of bioaccessible established daily intakes (BEDI) and the total bioaccessible target hazard quotients (TBTHQ) of Cd and As were also considerably higher in high level co-contaminated soils than in low level co-contaminated soils. Two genotypes (Meiguanqinggengcai and Zhenqing60F1) contained relatively low concentrations and bioaccessible Cd and As and, their BEDI and TBTHQ for Cd and As ranged below the tolerable limits set by the FAO/WHO (BEDI of Cd < 0.83 μg kg -1 bw day -1 , BEDI of As < 3 μg kg -1 bw day -1 ) and United States Environmental Protection Agency (TBTHQ for Cd and As < 1), this applied for both levels of co-contaminated soils for adults and children. Consequently, these findings suggest identification of safe genotypes in leafy vegetable with low health risk via genotypic screening and breeding methods could be a useful strategy to ensure the safety of food crops grown in those Cd and As co-contaminated

STS-2, -3, -4 Induced Environment Contamination Monitor (ICEM)

NASA Technical Reports Server (NTRS)

Miller, E. R. (Editor)

1983-01-01

The second, third, and fourth space transportation system missions are described including the location of the IECM in the payload bay and the shuttle coordinate systems used. Measurement results from the three flights are given for each instrument with comparisons to original goals for preflight environment and induced environment contamination. These results include very low levels of molecular mass accumulation rates, absence of molecular films on optical samples, outgassing species above 50 amu undetectable generally low levels of on-orbit particulates, and decay rates for early mission water dump particulates. Results of exposure of several optical materials and coatings to atomic oxygen are also presented. From these results, it is concluded that the space shuttle met the established induced environment contamination goals.

Risk assessment and pathway study of arsenic in industrially contaminated sites of Hyderabad: a case study.

PubMed

Chandra Sekhar, K; Chary, N S; Kamala, C T; Venkateswara Rao, J; Balaram, V; Anjaneyulu, Y

2003-08-01

Different areas in the industrial region of Patancheru near Hyderabad, Andhra Pradesh (A.P), India are contaminated with high concentration of arsenic, which is attributed to industrial source like veterinary chemicals, pharmaceuticals, pesticide industries, etc. Fourteen villages of this area of Patancheru were assessed for arsenic contamination by collecting samples of water (surface and ground), soil, fodder, milk, and vegetables. The total arsenic content in the whole blood, urine, hair, and nails of the residents showing arsenical skin lesions and other clinical manifestations were also studied. To understand the bioavailability of arsenic in this environment and its possible entry into human food chain, speciation studies of arsenic was carried out and the results are presented in this paper.

Current approaches for the assessment of in situ biodegradation.

PubMed

Bombach, Petra; Richnow, Hans H; Kästner, Matthias; Fischer, Anko

2010-04-01

Considering the high costs and technical difficulties associated with conventional remediation strategies, in situ biodegradation has become a promising approach for cleaning up contaminated aquifers. To verify if in situ biodegradation of organic contaminants is taking place at a contaminated site and to determine if these processes are efficient enough to replace conventional cleanup technologies, a comprehensive characterization of site-specific biodegradation processes is essential. In recent years, several strategies including geochemical analyses, microbial and molecular methods, tracer tests, metabolite analysis, compound-specific isotope analysis, and in situ microcosms have been developed to investigate the relevance of biodegradation processes for cleaning up contaminated aquifers. In this review, we outline current approaches for the assessment of in situ biodegradation and discuss their potential and limitations. We also discuss the benefits of research strategies combining complementary methods to gain a more comprehensive understanding of the complex hydrogeological and microbial interactions governing contaminant biodegradation in the field.

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.

Slaughterhouses Fungal Burden Assessment: A Contribution for the Pursuit of a Better Assessment Strategy

PubMed Central

Viegas, Carla; Faria, Tiago; dos Santos, Mateus; Carolino, Elisabete; Sabino, Raquel; Quintal Gomes, Anita; Viegas, Susana

2016-01-01

In slaughterhouses, the biological risk is present not only from the direct or indirect contact with animal matter, but also from the exposure to bioaerosols. Fungal contamination was already reported from the floors and walls of slaughterhouses. This study intends to assess fungal contamination by cultural and molecular methods in poultry, swine/bovine and large animal slaughterhouses. Air samples were collected through an impaction method, while surface samples were collected by the swabbing method and subjected to further macro- and micro-scopic observations. In addition, we collected air samples using the impinger method in order to perform real-time quantitative PCR (qPCR) amplification of genes from specific fungal species, namely A. flavus, A. fumigatus and A. ochraceus complexes. Poultry and swine/bovine slaughterhouses presented each two sampling sites that surpass the guideline of 150 CFU/m3. Scopulariopsis candida was the most frequently isolated (59.5%) in poultry slaughterhouse air; Cladosporium sp. (45.7%) in the swine/bovine slaughterhouse; and Penicillium sp. (80.8%) in the large animal slaughterhouse. Molecular tools successfully amplified DNA from the A. fumigatus complex in six sampling sites where the presence of this fungal species was not identified by conventional methods. This study besides suggesting the indicators that are representative of harmful fungal contamination, also indicates a strategy as a protocol to ensure a proper characterization of fungal occupational exposure. PMID:27005642

Mineral transformation controls speciation and pore-fluid transmission of contaminants in waste-weathered Hanford sediments

NASA Astrophysics Data System (ADS)

Perdrial, Nicolas; Thompson, Aaron; O'Day, Peggy A.; Steefel, Carl I.; Chorover, Jon

2014-09-01

Portions of the Hanford Site (WA, USA) vadose zone were subjected to weathering by caustic solutions during documented releases of high level radioactive waste (containing Sr, Cs and I) from leaking underground storage tanks. Previous studies have shown that waste-sediment interactions can promote variable incorporation of contaminants into neo-formed mineral products (including feldspathoids and zeolites), but processes regulating the subsequent contaminant release from these phases into infiltrating background pore waters remain poorly known. In this paper, reactive transport experiments were conducted with Hanford sediments previously weathered for one year in simulated hyper-alkaline waste solutions containing high or low 88Sr, 127I, and 133Cs concentrations, with or without CO2(aq). These waste-weathered sediments were leached in flow-through column experiments with simulated background pore water (characteristic of meteoric recharge) to measure contaminant release from solids formed during waste-sediment interaction. Contaminant sorption-desorption kinetics and mineral transformation reactions were both monitored using continuous-flow and wet-dry cycling regimes for ca. 300 pore volumes. Less than 20% of contaminant 133Cs and 88Sr mass and less than 40% 127I mass were released over the course of the experiment. To elucidate molecular processes limiting contaminant release, reacted sediments were studied with micro- (TEM and XRD) and molecular- (Sr K-edge EXAFS) scale methods. Contaminant dynamics in column experiments were principally controlled by rapid dissolution of labile solids and competitive exchange reactions. In initially feldspathoidic systems, time-dependent changes in the local zeolitic bonding environment observed with X-ray diffraction and EXAFS are responsible for limiting contaminant release. Linear combination fits and shell-by-shell analysis of Sr K-edge EXAFS data revealed modification in Sr-Si/Al distances within the zeolite cage. Wet

Novel contaminants identified in fish kills in the Red River watershed, 2011–2013

EPA Science Inventory

Provisional molecular weights and chemical formulas were assigned to four significant previously unidentified contaminants present during active fish kills in the Red River region of Oklahoma. The provisional identifications of these contaminants were determined using high-resolu...

Occurrence of chemical contaminants in peri-urban agricultural irrigation waters and assessment of their phytotoxicity and crop productivity.

PubMed

Margenat, Anna; Matamoros, Víctor; Díez, Sergi; Cañameras, Núria; Comas, Jordi; Bayona, Josep M

2017-12-01

Water scarcity and water pollution have increased the pressure on water resources worldwide. This pressure is particularly important in highly populated areas where water demand exceeds the available natural resources. In this regard, water reuse has emerged as an excellent water source alternative for peri-urban agriculture. Nevertheless, it must cope with the occurrence of chemical contaminants, ranging from trace elements (TEs) to organic microcontaminants. In this study, chemical contaminants (i.e., 15 TEs, 34 contaminants of emerging concern (CECs)), bulk parameters, and nutrients from irrigation waters and crop productivity (Lycopersicon esculentum Mill. cv. Bodar and Lactuca sativa L. cv. Batavia) were seasonally surveyed in 4 farm plots in the peri-urban area of the city of Barcelona. A pristine site, where rain-groundwater is used for irrigation, was selected for background concentrations. The average concentration levels of TEs and CECs in the irrigation water impacted by treated wastewater (TWW) were 3 (35±75μgL -1 ) and 13 (553±1050ngL -1 ) times higher than at the pristine site respectively. Principal component analysis was used to classify the irrigation waters by chemical composition. To assess the impact of the occurrence of these contaminants on agriculture, a seed germination assay (Lactuca sativa L) and real field-scale study of crop productivity (i.e., lettuce and tomato) were used. Although irrigation waters from the peri-urban area exhibited a higher frequency of detection and concentration of the assessed chemical contaminants than those of the pristine site (P1), no significant differences were found in seed phytotoxicity or crop productivity. In fact, the crops impacted by TWW showed higher productivity than the other farm plots studied, which was associated with the higher nutrient availability for plants. Copyright © 2017 Elsevier B.V. All rights reserved.

Assessment of soil-gas and soil contamination at the South Prong Creek Disposal Area, Fort Gordon, Georgia, 2009-2010

USGS Publications Warehouse

Caldwell, Andral W.; Falls, W. Fred; Guimaraes, Wladmir B.; Ratliff, W. Hagan; Wellborn, John B.; Landmeyer, James E.

2011-01-01

Soil gas and soil were assessed for contaminants at the South Prong Creek Disposal Area at Fort Gordon, Georgia, from October 2009 to September 2010. The assessment included identifying and delineating organic contaminants present in soil-gas and inorganic contaminants present in soil samples collected from the area estimated to be the South Prong Creek Disposal Area, including two seeps and the hyporheic zone. This assessment was conducted to provide environmental contamination data to Fort Gordon personnel pursuant to requirements for the Resource Conservation and Recovery Act Part B Hazardous Waste Permit process. All soil-gas samplers in the two seeps and the hyporheic zone contained total petroleum hydrocarbons above the method detection level. The highest total petroleum hydrocarbon concentration detected from the two seeps was 54.23 micrograms per liter, and the highest concentration in the hyporheic zone was 344.41 micrograms per liter. The soil-gas samplers within the boundary of the South Prong Creek Disposal Area and along the unnamed road contained total petroleum hydrocarbon mass above the method detection level. The highest total petroleum hydrocarbon mass detected was 147.09 micrograms in a soil-gas sampler near the middle of the unnamed road that traverses the South Prong Creek Disposal Area. The highest undecane mass detected was 4.48 micrograms near the location of the highest total petroleum hydrocarbon mass. Some soil-gas samplers detected undecane mass greater than the method detection level of 0.04 micrograms, with the highest detection of toluene mass of 109.72 micrograms in the same location as the highest total petroleum hydrocarbon mass. Soil-gas samplers installed in areas of high contaminant mass had no detections of explosives and chemical agents above their respective method detection levels. Inorganic concentrations in five soil samples did not exceed regional screening levels established by the U.S. Environmental Protection Agency