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Sample records for molecular contamination assessments

  1. Molecular Contamination Assessments on Hinode X-Ray Telescope

    NASA Astrophysics Data System (ADS)

    Urayama, Fumitaka; Bando, Takamasa; Kano, Ryouhei; Hara, Hirohisa; Narukage, Noriyuki; Sakao, Taro

    The Hinode (Solar-B) was launched by M-V rocket on 22 September 2006 UT. The telemetry data of the Hinode X-ray Telescope (XRT) showed that the X-ray count rate detected with the XRT had decreased rapidly since the operational heaters on the XRT telescope tube were turned on. This is attributed to the fact that molecular contaminants accumulated onto the CCD with the temperature of -60ºC resulting in the degradation of the XRT sensitivity. We baked the CCD at the temperature of 35ºC in order to remove the contaminants from the CCD surface. However many contaminant spots appeared on the surface. We found that major contaminant source existed in the telescope tube, and identified the contaminants as diethylhexyl phthalate (DEHP) or DEHP-like organics. The mechanisms to yield the contaminant spots were discussed.

  2. Molecular methods to assess Listeria monocytogenes route of contamination in a dairy processing plant.

    PubMed

    Alessandria, Valentina; Rantsiou, Kalliopi; Dolci, Paola; Cocolin, Luca

    2010-07-31

    In this study we investigated the occurrence of Listeria monocytogenes in a dairy processing plant during two sampling campaigns in 2007 and 2008. Samples represented by semifinished and finished cheeses, swabs from the equipment and brines from the salting step, were subjected to analysis by using traditional and molecular methods, represented mainly by quantitative PCR. Comparing the results obtained by the application of the two approaches used, it became evident how traditional microbiological analysis underestimated the presence of L. monocytogenes in the dairy plant. Especially samples of the brines and the equipment swabs were positive only with qPCR. For some equipment swabs it was possible to detect a load of 10(4)-10(5) cfu/cm(2), while the modified ISO method employed gave negative results both before and after the enrichment step. The evidences collected during the first sampling year, highlighting a heavy contamination of the brines and of the equipment, lead to the implementation of specific actions that decreased the contamination in these samples during the 2008 campaign. However, no reduction in the number of L. monocytogenes positive final products was observed, suggesting that a more strict control is necessary to avoid the presence of the pathogen. All the isolates of L. monocytogenes were able to attach to abiotic surfaces, and, interestingly, considering the results obtained from their molecular characterization it became evident how strains present in the brines, were genetically connected with isolates from the equipment and from the final product, suggesting a clear route of contamination of the pathogen in the dairy plant. This study underlines the necessity to use appropriate analytical tools, such as molecular methods, to fully understand the spread and persistence of L. monocytogenes in food producing companies. PMID:20193970

  3. Molecular biomarkers to assess health risks due to environmental contaminants exposure.

    PubMed

    Poblete-Naredo, Irais; Albores, Arnulfo

    2016-01-01

    Biomarkers, or bioindicators, are metric tools that, when compared with reference values, allow specialists to perform risk assessments and provide objective information to decision makers to design effective strategies to solve health or environmental problems by efficiently using the resources assigned. Health risk assessment is a multidisciplinary exercise, and molecular biology is a discipline that greatly contributes to these evaluations because the genome, transcriptome, proteome and metabolome could be affected by xenobiotics causing measurable changes that might be useful biomarkers. Such changes may greatly depend on individual genetic background; therefore, the polymorphic distribution of exposed populations becomes an essential feature for adequate data interpretation. The aim of this paper is to offer an up-to-date review of the role of different molecular biomarkers in health risk assessments. PMID:27622493

  4. Molecular and phylogenetic approaches for assessing sources of Cryptosporidium contamination in water.

    PubMed

    Ruecker, Norma J; Matsune, Joanne C; Wilkes, Graham; Lapen, David R; Topp, Edward; Edge, Thomas A; Sensen, Christoph W; Xiao, Lihua; Neumann, Norman F

    2012-10-15

    The high sequence diversity and heterogeneity observed within species or genotypes of Cryptosporidium requires phylogenetic approaches for the identification of novel sequences obtained from the environment. A long-term study on Cryptosporidium in the agriculturally-intensive South Nation River watershed in Ontario, Canada was undertaken, in which 60 sequence types were detected. Of these sequence types 33 were considered novel with no identical matches in GenBank. Detailed phylogenetic analysis identified that most sequences belonged to 17 previously described species: Cryptosporidium andersoni, Cryptosporidium baileyi, Cryptosporidium hominis, Cryptosporidium parvum, Cryptosporidium ubiquitum, Cryptosporidium meleagridis, muskrat I, muskrat II, deer mouse II, fox, vole, skunk, shrew, W12, W18, W19 and W25 genotypes. In addition, two new genotypes were identified, W27 and W28. C. andersoni and the muskrat II genotype were most frequently detected in the water samples. Species associated with livestock made up 39% of the total molecular detections, while wildlife associated species and genotypes accounted for 55% of the Cryptosporidium identified. The human pathogenic species C. hominis and C. parvum had an overall prevalence of 1.6% in the environment, indicating a small risk to humans from the Cryptosporidium present in the watershed. Phylogenetic analysis and knowledge of host-parasite relationships are fundamental in using Cryptosporidium as a source-tracking or human health risk assessment tool. PMID:22841595

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

    SciTech Connect

    Arai, Y.; Tappero, R.; Rick, A.R.; Saylor, T.; Faas, E. & Lanzirotti, A.

    2011-05-24

    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 understand 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 hunting

  6. 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

  7. Monitoring reticle molecular contamination in ASML EUV Alpha Demo Tool

    NASA Astrophysics Data System (ADS)

    Okoroanyanwu, Uzodinma; Jiang, Aiqin; Dittmar, Kornelia; Fahr, Torsten; Laursen, Thomas; Wood, Obert; Cummings, Kevin; Holfeld, Christian; Peters, Jan-Hendrik; Gullikson, Eric; La Fontaine, Bruno

    2010-04-01

    Molecular contamination risk to an EUV reticle exposed to up to 1600J/cm2 of 13.5 nm EUV radiation in ASML Alpha Demo Tool (ADT) is negligible. Carbon film (< 0.5 nm) deposition and oxidation (surface oxides ~1 nm) are the two main molecular contaminants observed on this EUV reticle. These results run counter to recent empirical results obtained from EUV micro-exposure tools (MET) which suggest that molecular contamination of EUV reticles, even at the very low partial pressures expected in the exposure chamber of EUV exposure tools, poses challenges in the implementation of EUV lithography in large-scale volume manufacturing of devices. To assess the molecular contamination risk to the use and lifetime of a given EUV reticle, we monitored the contamination buildup on a specially designed reticle during one year as it was exposed on ASML ADT located in Albany, New York. The reticle was analyzed with a suite of complementary surface analytical technique (such as Auger Electron Spectroscopy, AES) and chemical analytical techniques (such as Grazing Incidence Reflection Fourier Transform Infra-red Spectroscopy, GIR-FTIR), as well as imaging technique (such as Scanning Electron Microscopy). The influence of molecular contamination on the reflectivity of this reticle was measured at the Lawrence Berkeley Advanced Light Source EUV reflectometry. The differences in the contamination outcome of EUV reticles exposed in ASML ADT and MET may be related to the implementation of active contamination mitigation schemes in ADT and the lack of similar schemes in METs.

  8. Microbial communities in a chlorinated solvent contaminated tidal freshwater wetland: molecular techniques for assessing potentially important biodegrading organisms

    NASA Astrophysics Data System (ADS)

    Kirshtein, J. D.; Voytek, M. A.; Lorah, M m

    2001-05-01

    Aberdeen Proving Ground MD (APG) is a hazardous waste site where a chlorinated solvent plume discharges into anaerobic sediments in a tidal freshwater wetland. Wetlands can be ideal sites for intrinsic remediation of chlorinated volatile organic compounds (VOCs) due to availability of organic substrates and the wide range of redox zones. And indeed natural attenuation of these compounds appears to be an important process at this site. The biodegradation of chlorinated VOCs such as PCA can follow several pathways: 1) sequential hydrogenolysis of PCA to ethane or ethene via TCA 2) dichloroelimation of TCA to vinyl chloride (VC) or 3) dichloroelimination of PCA to DCE, and hydrogenolysis of DCE to VC. Pathways 2 and 3 can result in the accumulation of VC which is considered more hazardous than the original parent compounds. Identifying microbial components involved in the series of degradation steps of each pathway can provide a better understanding of factors controlling the intrinsic bioremediation of these compounds. PCA-amended microcosm experiments were conducted during two seasons, March-April, and July-August 1999 at APG using wetland sediments collected from two distinct sites (one is methanogenic and one is both iron reducing and methanogenic). During the course of the experiments, VOCs, methane, ferrous iron and sulfate were measured. Terminal restriction fragment polymorphism (tRFLP) analysis provides a molecularly-derived microbial "fingerprint" and was used to document the total microbial abundance and characterize the diversity of the bacterial and methanogen communities. Higher rates of degradation observed during the spring sampling were associated with higher biomass and microbial diversity. As the microcosm proceeded, shifts in redox conditions and associated degradation rates and pathways were observed. These shifts were tracked by changes in the microbial community. Three phylotypes were identified that appear to be important in controlling the

  9. 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.

  10. 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.

  11. Mie Scattering of Growing Molecular Contaminants

    NASA Technical Reports Server (NTRS)

    Herren, Kenneth A.; Gregory, Don A.

    2007-01-01

    Molecular contamination of optical surfaces from outgassed material has been shown in many cases to proceed from acclimation centers and to produce many roughly hemispherical "islands" of contamination on the surface. The mathematics of the hemispherical scattering is simplified by introducing a Virtual source below the plane of the optic, in this case a mirror, allowing the use of Mie theory to produce a solution for the resulting sphere .in transmission. Experimentally, a fixed wavelength in the vacuum ultraviolet was used as the illumination source and scattered light from the polished and coated glass mirrors was detected at a fixed angle as the contamination islands grew in time.

  12. Analysis of Molecular Contamination on Genesis Collectors Through Spectroscopic Ellipsometry

    NASA Technical Reports Server (NTRS)

    McNamara, K. M.; Stansbery, Eileen K.

    2005-01-01

    Before the spacecraft returned to Earth in September, the Genesis mission had a preliminary assessment plan in place for the purpose of providing information on the condition and availability of collector materials to the science community as a basis for allocation requests. One important component of that plan was the evaluation of collector surfaces for molecular contamination. Sources of molecular contamination might be the on-orbit outgassing of spacecraft and science canister components, the condensation of thruster by-products during spacecraft maneuvers, or the condensation of volatile species associated with reentry. Although the non-nominal return of the Genesis spacecraft introduced particulate contamination to the collectors, such as dust and heatshield carbon-carbon, it is unlikely to have caused any molecular deposition. The contingency team's quick action in returning the damaged payload the UTTR cleanroom by 6 PM the evening of recovery help to ensure that exposure to weather conditions and the environment were kept to a minimum.

  13. WESTERN AIRBORNE CONTAMINANTS ASSESSMENT PROJECT RESEARCH PLAN

    EPA Science Inventory

    The goal of the Western Airborne Contaminants Assessment Project (WACAP) is to assess the deposition of airborne contaminants in Western National Parks, providing regional and local information on exposure, accumulation, impacts, and probable sources. This project is being desig...

  14. Molecular Contamination Investigation Facility (MCIF) Capabilities

    NASA Technical Reports Server (NTRS)

    Soules, David M.

    2013-01-01

    This facility was used to guide the development of ASTM E 1559 center dot Multiple Quartz Crystal Microbalances (QCMs), large sample and spectral effects capability center dot Several instrumented, high vacuum chamber systems are used to evaluate the molecular outgassing characteristics of materials, flight components and other sensitive surfaces. Test materials for spacecraft/instrument selection center.Test flight components for acceptable molecular outgas levels center dot Determine time/temperature vacuum bake-out requirements center. Data used to set limits for use of materials and specific components center. Provide Input Data to Contamination Transport Models -Applied to numerous flight projects over the past 20 years.

  15. Space station contamination study: Assessment of contaminant spectral brightness

    NASA Technical Reports Server (NTRS)

    Torr, D. G.

    1988-01-01

    The assessment of spectral brightness resulting from the ambient-contaminant interaction requires a knowledge of the details of cross sections and excitation mechanisms. The approach adopted was to utilize the spectral brightness measurements made on Spacelab 1 and on the S3-4 spacecraft to identify source mechanisms, key cross sections and hence, the abundance of contaminant species. These inferred abundances were then used to update the composition comprising the total column concentrations predicted by the Science and Engineering Associates' configuration contamination model for the Space Station and to scale the irradiances to four altitudes: 300, 350, 400, and 463 km. The concentration irradiances are compared with zodiacal natural background levels. The results demonstrate that emissive contamination is significantly more severe than anticipated. It is shown that spectral emissions can become competitive with the zodiacal background up to altitudes as high as 400 km for the vacuum ultraviolet and visible emissions.

  16. 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.

  17. Bioassay for assessing marine contamination

    SciTech Connect

    Lapota, D.; Copeland, H.; Mastny, G.; Rosenberger, D.; Duckworth, D.

    1996-03-01

    The Qwiklite bioassay, developed by the laboratory at NCCOSC, is used as a biological tool to gauge the extent of environmental contamination. Some species of marine phytoplankton produce bioluminescence. The Qwiklite bioassay determines acute response and chronic effects of a wide variety of toxicants upon bioluminescent dinotlagellates by measuring their light output after exposure.

  18. Modeling Ellipsometry Measurements of Molecular Thin-Film Contamination on Genesis Array Samples

    NASA Technical Reports Server (NTRS)

    Calaway, Michael J.; Stansbery, E. K.; McNamara, K. M.

    2006-01-01

    The discovery of a molecular thin-film contamination on Genesis flown array samples changed the course of preliminary assessment strategies. Analytical techniques developed to measure solar wind elemental abundances must now compensate for a thin-film contamination. Currently, this is done either by experimental cleaning before analyses or by depth-profiling techniques that bypass the surface contamination. Inside Johnson Space Center s Genesis dedicated ISO Class 4 (Class 10) cleanroom laboratory, the selection of collector array fragments allocated for solar wind analyses are based on the documentation of overall surface quality, visible surface particle contamination greater than 1 m, and the amount of thin film contamination measured by spectroscopic ellipsometry. Documenting the exact thickness, surface topography, and chemical composition of these contaminates is also critical for developing accurate cleaning methods. However, the first step in characterization of the molecular film is to develop accurate ellipsometry models that will determine an accurate thickness measurement of the contamination film.

  19. Determination of molecular contamination performance for space chamber tests

    NASA Technical Reports Server (NTRS)

    Scialdone, J. J.

    1973-01-01

    The limitations of chamber tests with regard to the molecular contamination of a spacecraft undergoing vacuum test were examined. The molecular flow conditions existing in the chamber and the parameters dictating the degree of contamination were analyzed. Equations and graphs were developed to show the fraction of molecules returning to the spacecraft out of those emitted and to show other chamber flow parameters as a function of chamber and spacecraft surface molecular pumping and geometric configuration. Type and location of instruments required to measure the outgassing, the degree of contamination, and the returning flows are also discussed.

  20. Preliminary Assessment Of SIRE's Potential For Contamination

    NASA Astrophysics Data System (ADS)

    Mah, D. L.; Muscari, J. A.

    1981-07-01

    This paper presents the results of a contamination analysis and computer modeling study performed for the Space Infrared Experiment (SIRE) using the Space Transport System (STS) Shuttle Orbiter as the launch vehicle for the proposed seven-day sortie mission. These results will provide an accurate description of the deposition levels on the telescope primary mirror and of the molecular number column density (NCD) along the telescope line-of-sight. The planned Helium Purge System was assumed not to be operating. The contri-bution to the contamination environment of any cargo element, other than SIRE and its pallet, was not considered in this study. The study considers five potential contamination sources, including the flash evaporator vent effluents and the vernier reaction control system (VCS) engines plume constituents.

  1. 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.

  2. 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. PMID:27267743

  3. Molecular contamination study by interaction of a molecular beam with a platinum surface

    NASA Technical Reports Server (NTRS)

    Nuss, H. E.

    1976-01-01

    The capability of molecular beam scattering from a solid surface is analyzed for identification of molecular contamination of the surface. The design and setup of the molecular beam source and the measuring setup for the application of a phase sensitive measuring technique for the determination of the scattered beam intensity are described. The scattering distributions of helium and nitrogen molecular beams interacting with a platinum surface were measured for different amounts of contamination from diffusion pump oil for surface temperatures ranging from 30 to 400 C. The results indicate the scattering of molecular beams from a platinum surface is a very sensitive method for detecting surface contamination.

  4. 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...

  5. Molecular identification, characterization and assessment of virulence of non-culturable biofilm isolates of L. monocytogenes isolated from chronic infections of turkeys: Implications for product and plant contamination

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have hypothesized that sub-clinical, stress-induced infection of turkeys may be an unrecognized source of processing plant contamination with Listeria monocytogenes (Lm) biofilm. The objectives of this study were to determine the effects of early cold stress and concurrent environmental challenge...

  6. 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

  7. Spacelab contamination assessment. Payload/orbiter contamination control requirement study

    NASA Technical Reports Server (NTRS)

    Bareiss, L. E.; Hetdrick, M. A.; Ress, E. B.

    1977-01-01

    The activities and the results obtained under the payload/orbiter contamination control requirement study were documented, and the integrated shuttle payload contamination evaluation computer model was developed. Spacelab design and development analysis based upon the predicted Spacelab induced contaminant environments were conducted utilizing the space program.

  8. Ecological risk assessment of contaminated soil.

    PubMed

    Jensen, John; Pedersen, Marianne Bruus

    2006-01-01

    This review has described three cases of ecological risk assessment. The cases include two heavy metals (Cu and Zn) and an anthropogenic organic chemical (DDT). It concludes that there are at least two major constraints hampering the use of laboratory tests to predict effects under natural field conditions. One key issue is bioavailability, and another is suboptimal conditions or multiple stresses in the field such as climatic stress (drought, frost), predators, competition, or food shortage. On the basis of the presented case studies, it was possible to answer three essential questions often raised in connection to ecological risk assessment of contaminated sites. 1. To what extend does soil screening level (SSL) estimate the risk? The SSL are generally derived at levels corresponding to the lowest observed effect levels in laboratory studies, which often is close to the background levels found in many soils. In the cases of zinc and especially DDT, the SSL seemed quite conservative, whereas for copper they resemble the level at which changes in the community structure of soil microarthropods and the plant community have been observed at contaminated sites. The SSL correspond as a whole relatively well with concentrations where no effects or only minor effects were observed in controlled field studies. However, large variation in field surveys can often make it difficult to conclude to what extent the SSL corresponded to no-effect levels in the field. 2. Do bioassays represent a more realistic risk estimate? Here, there is no firm conclusion. The zinc study in UK showed a better relationship between the outcome of ex situ bioassays and field observations than the SSL. The latter overestimated the risk compared to field observations. However, this would be species dependent, as the sensitivity to metals may vary considerably between recognized test species, even within the same group of organisms, such as Folsomia candida and Folsomia fimetaria or Eisenia fetida

  9. Field Analysis of Microbial Contamination Using Three Molecular Methods in Parallel

    NASA Technical Reports Server (NTRS)

    Morris, H.; Stimpson, E.; Schenk, A.; Kish, A.; Damon, M.; Monaco, L.; Wainwright, N.; Steele, A.

    2010-01-01

    Advanced technologies with the capability of detecting microbial contamination remain an integral tool for the next stage of space agency proposed exploration missions. To maintain a clean, operational spacecraft environment with minimal potential for forward contamination, such technology is a necessity, particularly, the ability to analyze samples near the point of collection and in real-time both for conducting biological scientific experiments and for performing routine monitoring operations. Multiple molecular methods for detecting microbial contamination are available, but many are either too large or not validated for use on spacecraft. Two methods, the adenosine- triphosphate (ATP) and Limulus Amebocyte Lysate (LAL) assays have been approved by the NASA Planetary Protection Office for the assessment of microbial contamination on spacecraft surfaces. We present the first parallel field analysis of microbial contamination pre- and post-cleaning using these two methods as well as universal primer-based polymerase chain reaction (PCR).

  10. Assessment of surface contamination with contact mechanics

    SciTech Connect

    EMERSON,JOHN A.; MILLER,GREGORY V.; SORENSEN,CHRISTOPHER R.; PEARSON,RAYMOND A.

    2000-02-21

    The authors are particularly interested in the work of adhesion measurements as a means to facilitate the understanding of the adhesive failure mechanisms for systems containing encapsulated and bonded components. Of the several issues under investigation, one is the effect of organic contamination on the adhesive strength for several types of polymer/metal interface combinations. The specific question that the authors are trying to address is at what level of contamination does adhesive strength decrease. The use of contact mechanics, the JKR method, is a good approach for studying this question. Another approach being studied is the use of interracial fracture mechanics. The model contaminant is hexadecane--non-polar, medium molecular weight hydrocarbon fluid. They choose hexadecane because it replicates typical machining fluids, is nonreactive with Al surfaces, and should not dissolve readily into the adhesive systems of interest. The application of a uniform, controllable and reproducible hexadecane layer on Al surfaces has proven to be difficult. A primary concern is whether studies of model systems can be extended to systems of technological interest. The JKR theory is a continuum mechanics model of contact between two solid spheres that was developed by Johnson, Kendall and Roberts. The JKR theory is an extension of Hertzian contact theory and attributes the additional increase in the contact area between a soft elastomeric hemisphere to adhesive forces between the two surfaces. The JKR theory allows a direct estimate of the surface free energy of interface as well as the work of adhesion (Wa) between solids. Early studies performed in this laboratory involved the determination of Wa between silicone (PDMS) and Al surfaces in order to establish the potential adhesive failure mechanisms. However, the JKR studies using commercial based PDMS [poly(dimethylsiloxane)] was fraught with difficulty that were attributed to the additives used in commercial PDMS

  11. 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. PMID:16175730

  12. 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.

  13. 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.

  14. 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.

  15. Molecular analysis for bacterial contamination in dental unit water lines.

    PubMed

    Watanabe, Akari; Tamaki, Naofumi; Matsuyama, Miwa; Kokeguchi, Susumu

    2016-04-01

    Bacterial contamination in dental unit waterlines (DUWLs) was evaluated by molecular techniques in addition to the conventional culture method. Water samples (n=8) from DUWLs were investigated for heterotrophic bacteria by culture method using R2A agar. The selected bacterial antibiotic-resistance genes and Legionella species-specific 16SrDNA were identified by PCR. The profiles of bacterial contamination in DUWLs were further identified by PCR-DGGE. In this study, no antibiotic-resistant or Legionella genes were detected. Polycyclic aromatic hydrocarbon-degrading bacterium, Novosphingobium sp. was the most prevalent in DUWLs. Conventional PCR and PCR-DGGE were shown to be potentially useful for monitoring of bacterial contamination in DUWLs. PMID:27196554

  16. Solid phase extraction of food contaminants using molecular imprinted polymers.

    PubMed

    Baggiani, Claudio; Anfossi, Laura; Giovannoli, Cristina

    2007-05-15

    Food contamination from natural or anthropogenic sources poses severe risks to human health. It is now largely accepted that continuous exposure to low doses of toxic chemicals can be related to several chronic diseases, including some type of cancer and serious hormonal dysfunctions. Contemporary analytical methods have the sensitivity required for contamination detection and quantification, but direct application of these methods on food samples can be rarely performed. In fact, the matrix introduces severe disturbances, and analysis can be performed only after some clean-up and preconcentration steps. Current sample pre-treatment methods, mostly based on the solid phase extraction technique, are very fast and inexpensive but show a lack of selectivity, while methods based on immunoaffinity extraction are very selective but expensive and not suitable for harsh environments. Thus, inexpensive, rapid and selective clean-up methods, relaying on "intelligent" materials are needed. Recent years have seen a significant increase of the "molecularly imprinted solid phase extraction" (MISPE) technique in the food contaminant analysis. In fact, this technique seems to be particularly suitable for extractive applications where analyte selectivity in the presence of very complex and structured matrices represents the main problem. In this review, several applications of MISPE in food contamination analysis will be discussed, with particular emphasis on the extraction of pesticides, drugs residua, mycotoxins and environmental contaminants. PMID:17456421

  17. 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.

  18. 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.

  19. Assessment of hot gas contaminant control

    SciTech Connect

    Rutkowski, M.D.; Klett, M.G.; Zaharchuk, R.

    1996-12-31

    The objective of this work is to gather data and information to assist DOE in responding to the NRC recommendation on hot gas cleanup by performing a comprehensive assessment of hot gas cleanup systems for advanced coal-based Integrated Gasification Combined Cycle (IGCC) and Pressurized Fluidized Bed Combustion (PFBC) including the status of development of the components of the hot gas cleanup systems, and the probable cost and performance impacts. The scope and time frame of information gathering is generally responsive to the boundaries set by the National Research council (NRC), but includes a broad range of interests and programs which cover hot gas cleanup through the year 2010. As the status of hot gas cleanup is continually changing, additional current data and information are being obtained for this effort from this 1996 METC Contractors` Review Meeting as well as from the 1996 Pittsburgh Coal Conference, and the University of Karlsruhe Symposium. The technical approach to completing this work consists of: (1) Determination of the status of hot gas cleanup technologies-- particulate collection systems, hot gas desulfurization systems, and trace contaminant removal systems; (2) Determination of hot gas cleanup systems cost and performance sensitivities. Analysis of conceptual IGCC and PFBC plant designs with hot gas cleanup have been performed. The impact of variations in hot gas cleanup technologies on cost and performance was evaluated using parametric analysis of the baseline plant designs and performance sensitivity.

  20. Space station contamination study: Assessment of contaminant spectral brightness

    NASA Technical Reports Server (NTRS)

    Torr, D. G.

    1990-01-01

    The results presented show that spectral emissions which arise as a result of vehicle-ambient atmospheric interactions are significant and can become competitive with the natural zodiacal background up to altitudes as high as 400 km for the Vacuun Ultraviolet (VUV) and Visible Infrared Spectra (VIS) for the worst case conditions used. The empirical database on the induced environment of space vehicles is very sparse, and these results are based on a number of assumptions and cannot be regarded as definitive at the present time. Since the technique for doing calculations of this kind was developed in its preliminary form for the purpose of this study, a list of greatly improved estimates are provided of the contamination irradiances. Tasks which are considered most important in order to achieve a higher confidence level for the preliminary conclusions drawn are provided.

  1. Plant sentinels and molecular probes that monitor environmental munitions contaminants

    SciTech Connect

    Jackson, P.J.; DeWitt, J.G.; Hill, K.K.; Kuske, C.R.; Kim, D.Y.

    1994-08-01

    Plants accumulate TNT and similar compounds from soil. Their sessile nature requires that plants adapt to environmental changes by biochemical and molecular means. In principle, it is possible to develop a monitoring capability based on expression of any gene that is activated by specific environmental conditions. The authors have identified plant genes activated upon exposure to TNT. Partial gene sequences allow design of DNA probes that measure TNT-induced gene activity. These will be used to develop sensitive assays that monitor gene expression in plants growing in environments possibly contaminated with explosives.

  2. 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.

  3. Airborne molecular contamination: quality criterion for laser and optical components

    NASA Astrophysics Data System (ADS)

    Otto, Michael

    2015-02-01

    Airborne molecular contaminations (AMCs) have been recognized as a major problem in semiconductor fabrication. Enormous technical and financial efforts are made to remove or at least reduce these contaminations in production environments to increase yield and process stability. It can be shown that AMCs from various sources in laser devices have a negative impact on quality and lifetime of lasers and optical systems. Outgassing of organic compounds, especially condensable compounds were identified as the main source for deterioration of optics. These compounds can lead to hazing on surfaces of optics, degradation of coating, reducing the signal transmission or the laser signal itself and can enhance the probability of laser failure and damage. Sources of organic outgassing can be molding materials, resins, seals, circuit boards, cable insulation, coatings, paints and others. Critical compounds are siloxanes, aromatic amines and high boiling aromatic hydrocarbons like phthalates which are used as softeners in plastic materials. Nowadays all sensitive assembly steps are performed in controlled cleanroom environments to reduce risks of contamination. We will demonstrate a high efficient air filter concept to remove AMCs for production environments with special AMC filters and methods for the qualification and monitoring of these environments. Additionally, we show modern techniques and examples for the pre-qualification of materials. For assembled components, we provide sampling concepts for a routine measurement for process, component and product qualification. A careful selection of previously tested and certified materials and components is essential to guarantee the quality of lasers and optical devices.

  4. 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. PMID:23644688

  5. Spatial assessment of the sewage contamination of Kuwait's marine areas.

    PubMed

    Saeed, Talat; Al-Shimmari, Fatima; Al-Mutairi, Ahmad; Abdullah, Hameeda

    2015-05-15

    Discharge of sewage to the coastal areas resulting in the deteriorating quality of seawater and polluted sediments has been one of important stressor in Kuwait. The objective of this study was to conduct spatial assessment of sewage contamination of coastal areas. The assessment was carried out by measuring fecal sterols as indicator of sewage contamination, in the marine sediments collected from 112 locations throughout the Kuwait's marine areas. The samples were extracted and sterols separated. Derivatized sterols were analyzed by GC/MS in selected ion monitoring mode. The results showed that areas in the vicinity of the sewage outfalls were heavily contaminated. The western part of Kuwait Bay was worst in terms of contamination level. Two off-shore sites in Kuwait Bay were also classified as contaminated. Coprostanol levels in Kuwait Bay ranged from 0 to 39,428 ng/g. Southern coastal areas were less severely contaminated. PMID:25691339

  6. 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...

  7. Assessment of contamination in the Shuttle bay

    NASA Technical Reports Server (NTRS)

    Jeffery, J. A.; Maag, C. R.; Seastrom, J. W.; Weber, M. F.

    1982-01-01

    The results of an analytical study to determine the contamination potential of the Galileo probe instruments while in the STS bay are presented. The study covered conditions wherein the instruments weren't covered, covers were used with vent paths of varying sizes, and if the instruments were sealed and a nitrogen purge was employed. The contamination limits for each of the Galileo instruments are considered. Analytic approximations are devised for the diffusion of particles from surfaces and materials in the Shuttle bay during the ascent phase, using Fick's second law of diffusion. It is recommended that an instrument purge be implemented during the first 15 min of Shuttle flight in order to carry the contaminants from both the bay fixtures and from the instruments into space. Covers are suggested as necessary for the most sensitive instruments.

  8. Toxicity assessment for RMA target contaminants. Volume 1. Endangerment assessment RMA, task 35. Final draft report

    SciTech Connect

    1987-06-01

    This report is detailed discussion of the evaluations performed to develop the toxicity assessment for RMA contaminants in soil. The objectives of the toxicity assessment are to determine the nature and extent of health and environmental hazards associated with exposure to contaminants present at the site and identify a quantitative index of toxicity for each target contaminant, referred to in this assessment as DT. The toxicity assessment for the RMA target contaminants has been performed consistent with published EPA guidelines and addresses only human health hazards associated with contaminants in soil. Each toxicity profile is composed of seven sections: 1. summary; 2. chemical and physical properties; and 3. transport and rate.

  9. 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...

  10. 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.

  11. New Technologies for Standoff Assessment of Radiological Contamination

    SciTech Connect

    Cherepy, N; Stevens, C; Wurtz, R; Sanner, R; Frank, M; Tillotson, T; Hrubesh, L; Dietrich, D; Dignon, J; Soufli, R

    2005-05-06

    Technologies to rapidly quantify surface activity with minimal worker contact would dramatically decrease the radiation dose a radiation worker receives in assessment and cleanup operations, while obtaining a clear image of exactly where dispersed contamination is located. LLNL efforts in the development of the Photochromic Radiation Dosimeter and the Imaging Assessment System will be described. Initial use of these technologies in decontamination and decommissioning of contaminated facilities demonstrates several significant advantages over standard techniques such as survey meters and swipes.

  12. Assessment of Molecular Modeling & Simulation

    SciTech Connect

    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 materials 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.

  13. Assessment of community contamination: a critical approach.

    PubMed

    Clark, Lauren; Barton, Judith A; Brown, Nancy J

    2002-01-01

    The purpose of this paper is to review data from two Superfund sites and describe the latitude of interpretation of "environmental risk" by residents living in the area, governmental agencies, and the media. The first community was located within a 5-mi perimeter of the Rocky Flats Environmental Technology Site (RFETS) outside Denver, Colorado. The second community was located on the south side of Tucson, Arizona, adjacent to the Tucson International Airport area (TIAA) Superfund site. Critical theory was the perspective used in this analysis and proposal of public health actions to attain social justice. Differences between the two populations' experiences with risk and contamination coincided with divergent levels of trust in government. RFETS residents demanded monitoring, whereas the minority residents at TIAA were ambivalent about their trust in government cleanup activities. Unraveling the purpose of "facts" and the social force of "truth" can direct nurses to address environmental justice issues. By policing governmental and business activities in halting or cleaning up environmental contamination, nurses may become mouthpieces for the concerns underlying the fragile surface of "virtual trust" in contaminated communities. Cutting through competing rhetoric to police environmental safety, the core function of assurance becomes what nurses do, not what they say. PMID:12182695

  14. 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

  15. Probabilistic assessment of ground-water contamination. 1: Geostatistical framework

    SciTech Connect

    Rautman, C.A.; Istok, J.D.

    1996-09-01

    Characterizing the extent and severity of ground-water contamination at waste sites is expensive and time-consuming. A probabilistic approach, based on the acceptance of uncertainty and a finite probability of making classification errors (contaminated relative to a regulatory threshold vs. uncontaminated), is presented as an alternative to traditional site characterization methodology. The approach utilizes geostatistical techniques to identify and model the spatial continuity of contamination at a site (variography) and to develop alternate plausible simulations of contamination fields (conditional simulation). Probabilistic summaries of many simulations provide tools for (a) estimating the range of plausible contaminant concentrations at unsampled locations, (b) identifying the locations of boundaries between contaminated and uncontaminated portions of the site and the degree of certainty in those locations, and (c) estimating the range of plausible values for total contaminant mass. The first paper in the series presents the geostatistical framework and illustrates the approach using synthetic data for a hypothetical site. The second paper presents an application of the proposed methodology to the probabilistic assessment of ground-water contamination at a site involving ground-water contamination by nitrate and herbicide in a shallow, unconfined alluvial aquifer in an agricultural area in eastern Oregon.

  16. Molecular conductivity indices for modelling toxicities of Great Lakes contaminants to Daphnia pulex

    USGS Publications Warehouse

    Hickey, James P.; Passino, Dora R.M.; Frank, Anthony M.

    1988-01-01

    Hazard assessment of hundreds of observed and potential contaminants in fish, sediment, and water of the Great Lakes is necessary to determine impact on fishery sources and other aquatic biota. The hundreds of new compunds introduced each year have few measured properties. Mathematical models based on quantitative structure-activity relationships (QSARs) provide rapid, inexpensive estimates of physical properties and toxicites. These models are useful when the contaminants are not commercially available for testing. To develop these predicitive models, acute bioassay results (48-hr EC50 of Daphnia pulex) of 62 compounds were regressed against several modes of molecular connectivity indices. The compunds were selected from the more hazardous classes in a list of 476 compunds tentatively identified by GC/MS in Great Lakes fish.

  17. Comprehensive methodology for ecological risk assessment of contaminated soils

    SciTech Connect

    Kuperman, R.G.

    1994-12-31

    Development of a comprehensive methodology for ecological risk assessment and monitoring of contaminated soils is essential to assess the impacts of environmental contaminants on soil community and biologically-mediated processes in soil. The proposed four-step plan involves (1) a thorough survey of the soil community to establish biodiversity and a base-line community structure, (2) toxicity trials on indicator species and whole soil invertebrate communities, (3) laboratory and field tests on indicator processes and (4) the use of statistical and simulation models to ascertain changes in the soil ecosystems. This methodology was used in portions of the US Army`s Aberdeen Proving Ground, Maryland as part of an ecological risk assessment. Previous soil analyses showed extensive surface soil contamination with metals, nitrate and PCBs. Preliminary results from field surveys of soil invertebrate communities showed significant reductions in total abundance of animals, reductions in the abundance of several taxonomic and functional groups of soil invertebrates, and changes in the activity of epigeic arthropods in contaminated areas when compared with the local ``background`` area. Laboratory tests also demonstrated that microbial activity and success of egg hatching of ground beetle Harpalus pensylvanicus were reduced in contaminated soils. These results suggest that impacts to soil ecosystems should be explicitly considered in ecological risk assessment. The proposed comprehensive methodology appears to offer an efficient and potentially cost saving tool for remedial investigations of contaminated sites.

  18. 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). PMID:23307052

  19. 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.

  20. 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...

  1. Bidirectional Reflectance Function Measurement of Molecular Contaminant Scattering in the Vacuum Ultraviolet

    NASA Technical Reports Server (NTRS)

    Herren, Kenneth A.; Gregory, Don A.

    2006-01-01

    Bi-directional reflectance distribution function (BRDF) measurements of optical surfaces both before and after molecular contamination were done using UV, VUV and visible light. Molecular contamination of optical surfaces from outgassed material has been shown in many cases to proceed from acclimation centers, and to produce many roughly hemispherical "islands" of contamination on the surface. Vacuum Ultraviolet (VW) wavelengths are used here to measure angularly scattered light from optical surfaces.

  2. Assessment of bioremediation of a contaminated wetland

    SciTech Connect

    Swindoll, C.M.; Perkins, R.E.; Gannon, J.T.; Holmes, M.; Fisher, G.A.

    1995-12-31

    Evidence exists that natural remediation processes are restoring the environmental quality of the wetlands contaminated with nitrobenzene (NB) and aniline (AN). Based on the initial investigation, it appears likely that natural biodegradation is a major mechanism contributing to the wetland restoration. In situ water chemistry indicates that conditions are conducive for the growth of anaerobic microorganisms, especially sulfate- and iron-reducing bacteria. Laboratory studies show that indigenous microbes can reduce NB under sulfate-reducing, denitrifying, and methanogenic conditions. However, AN, produced as the result of NB reduction, was biodegraded only under denitrifying conditions. In situ bioremediation may be enhanced with amendments of nitrate as an electron acceptor and yeast extract as a supplemental nutrient source. Additional studies are in progress to fully elucidate the optimal conditions for in situ biodegradation of AN and NB.

  3. 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

  4. Genetic effects of contaminant exposure--towards an assessment of impacts on animal populations.

    PubMed

    Hebert, P D; Luiker, M M

    1996-11-18

    This review aims both to identify the potential risks to animal populations as a consequence of exposure to genotoxins and to identify the techniques most useful in assessing these risks. These evaluations are complicated by the fact that contaminant exposure acts both to restructure naturally occurring genetic diversity and, when contaminants have mutagenic activity, to enhance the rate of introduction of new variation. There is now evidence that contaminant exposure often leads to change in the genetic attributes of natural populations. Short-lived organisms often develop resistance to contaminants, with only modest impacts on diversity in the balance of the genome, although massive mortality occurs during the gene replacement. Resistance is, however, less likely to evolve in species with small population size, such as many wildlife species. Such species will experience population declines or extinction as the impact of contaminants on physiological systems is not counteracted by gene replacements. Even when adaptation to exposure occurs, populations may suffer diminished fitness as a consequence of the mutagenic effects of contaminants. The expression of these effects range from an increase in the incidence of developmental abnormalities to shifts in chromosomal and gene structure. The assessment of this broad range of impacts can only be accomplished with a spectrum of analytical approaches. However, recent advances in molecular and developmental genetics are now making possible the detailed assessment of these mutagenic impacts in natural populations. PMID:8885423

  5. 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.

  6. 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. PMID:17994915

  7. Molecular Approaches to Development of Resistance to Preharvest Aflatoxin Contamination

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mycotoxins are fungal metabolites that can contaminate foods and feeds and cause toxic effects in higher organisms that consume the contaminated commodities. Therefore, mycotoxin contamination of foods and feeds results is a serious food safety issue and affects the competitiveness of agricultural ...

  8. 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.

  9. SOFTWARE TOOLS FOR ASSESSMENT OF CONTAMINATED SITES

    EPA Science Inventory

    Models have become an integral part of decision-making for many LUST sites if only because they form the basis of RCBA tiered assessments. Models, though, are based on a series of assumptions concerning how chemicals behave in the environment, how water flows through the ground,...

  10. New methodology for assessing the probability of contaminating Mars

    NASA Technical Reports Server (NTRS)

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

    1974-01-01

    Methodology is proposed to assess the probability that the planet Mars will be contaminated by terrestrial microorganisms aboard a spacecraft. The present NASA methods are extended to permit utilization of detailed information on microbial characteristics, the lethality of release and transport mechanisms, and of other information about the Martian environment. Different types of microbial release are distinguished, and for each release mechanism a probability of growth is computed. Using this new methodology, an assessment was carried out for the 1975 Viking landings on Mars. The resulting probability of contamination for each Viking lander is 6 x 10 to the -6 power, and is amenable to revision as additional information becomes available.

  11. 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...

  12. Passive sampling methods for contaminated sediments: risk assessment and management.

    PubMed

    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

    2014-04-01

    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. PMID

  13. Preliminary Assessment Of Space Infrared Experiment's (SIRE) Potential For Contamination

    NASA Astrophysics Data System (ADS)

    Mah, D. L.; Muscari, J. A.

    1982-02-01

    This paper presents the results of a contamination analysis and computer modeling study performed for the Space Infrared Experiment (SIRE) using the Space Transport System (STS) Shuttle Orbiter as the launch vehicle for the proposed seven-day sortie mission. These results will provide an accurate description of the deposition levels on the telescope primary mirror and of the molecular number column density (NCD) along the telescope line-of-sight. The planned Helium Purge System was assumed not to be operating. The contribution to the contamination environment of any cargo element, other than SIRE and its pallet, was not considered in this study. The study considers five potential contamination sources, including the flash evaporator vent effluents and the vernier reaction control system (VCS) engines plume constituents.

  14. A fuzzy areal assessment approach for potentially contaminated sites

    NASA Astrophysics Data System (ADS)

    Özdamar, Linet; Demirhan, Melek; Özpinar, Alper; Kilanç, Burak

    2000-04-01

    This article describes a new fuzzy areal site assessment approach in the detection of contaminated zones within a site which is under environmental investigation. Conventional techniques utilized in this field are mostly interpolation based. These methods interpolate the contaminant concentration values at unobserved locations using observed values. Unlike these interpolation techniques, the motivation of the approach introduced here consists of partitioning a given site into smaller sections. Partitioning is carried out iteratively where subregions of interest are divided into further smaller regions. This re-partitioning scheme leads to a dynamic grouping of observations, since areas of differing sizes and boundaries contain different sets of samples. The potential of an area to contain contaminated zones is assessed by a fuzzy measure which converts the data values in that area into an aggregate grade normalized on [0, 1]. Thus, this approach does not assume concentration values at unobserved locations, rather, an areal potential is evaluated.

  15. 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...

  16. 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...

  17. Toxicity assessment for RMA target contaminants. Volume 2. Endangerment assessment, RMA, task 35. Final draft report

    SciTech Connect

    1987-06-01

    This report is a detailed discussion of the evaluations performed to develop the toxicity assessment for RMA contaminants in soil. The objectives of the toxicity assessment are to: (1) determine the nature and extent of health and environmental hazards associated with exposure to contaminants present at the site and (2) identify a quantitative index of toxicity for each target contaminant, referred to in this assessment as DT. The toxicity assessment for the RMA target contaminants has been performed consistent with published EPA guidelines and addresses only human health hazards associated with contaminants in soil. Each toxicity profile is composed of seven sections: (1) summary; (2) chemical and physical properties; and (3) transport and fate.

  18. 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

  19. Status and Assessment of Chesapeake Bay Wildlife Contamination

    USGS Publications Warehouse

    Heinz, G.H.; Wiemeyer, Stanley N.; Clark, D.R., Jr.; 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.

  20. Status and assessment of Chesapeake Bay wildlife contamination

    SciTech Connect

    Heinz, G.H.; Wiemeyer, S.N.; Clark, D.R.; Albers, P.; Henry, P.

    1992-10-01

    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.

  1. Assessment of environmental contaminant-induced lymphocyte dysfunction.

    PubMed Central

    Silkworth, J B; Loose, L D

    1981-01-01

    Although it has been established that environmental contaminants can alter immune function, the mechanisms of action have yet to be determined. This paper reviews the effects of hydrocarbon environmental contaminants on lymphocyte function and presents an approach which may serve to delineate the mechanisms of action. The approach is based on the use of the developmental phases of an immune response and assays which can be used for their functional assessment. Possible interactions between environmental contaminants and lymphocyte function and factors which must be considered in the evaluation of immune status are discussed. In addition, a study on the influence of the chronic exposure to two polyhalogenated hydrocarbons, PCB and HCB, on several parameters of lymphocyte function in mice is presented. PMID:7016518

  2. A Contamination Vulnerability Assessment for the Sacramento Area Groundwater Basin

    SciTech Connect

    Moran, J E; Hudson, G B; Eaton, G F; Leif, R

    2004-03-10

    In response to concerns expressed by the California Legislature and the citizenry of the State of California, the State Water Resources Control Board (SWRCB), implemented a program to assess groundwater quality, and provide a predictive capability for identifying areas that are vulnerable to contamination. The program was initiated in response to concern over public supply well closures due to contamination by chemicals such as MtBE from gasoline, and solvents from industrial operations. As a result of this increased awareness regarding groundwater quality, the Supplemental Report of the 1999 Budget Act mandated the SWRCB to develop a comprehensive ambient groundwater-monitoring plan, and led to the initiation of the Ambient Groundwater Monitoring and Assessment (GAMA) Program. The primary objective of the GAMA Program is to assess the water quality and to predict the relative susceptibility to contamination of groundwater resources throughout the state of California. Under the GAMA program, scientists from Lawrence Livermore National Laboratory (LLNL) collaborate with the SWRCB, the U.S. Geological Survey, the California Department of Health Services (DHS), and the California Department of Water Resources (DWR) to implement the groundwater assessment program in cooperation with local water purveyors. In 2001 and 2002, LLNL carried out this vulnerability study in the groundwater basin of Sacramento suburban area, located to the north of the American River and to the east of the Sacramento River. The goal of the study is to provide a probabilistic assessment of the relative vulnerability of groundwater used for the public water supply to contamination from surface sources. This assessment of relative contamination vulnerability is made based on the results of two types of analyses that are not routinely carried out at public water supply wells: ultra low-level measurement of volatile organic compounds (VOCs), and groundwater age dating (using the tritium-helium-3

  3. Integrated fate and toxicity assessment for site contaminants

    SciTech Connect

    MacDonell, Margaret; Peterson, John; Finster, Molly; Douglas, R.

    2007-07-01

    Understanding the fate and toxicity of environmental contaminants is essential to framing practical management decisions. Forms and bioavailable concentrations often change over time due to natural physical, chemical, and biological processes. For some sites, hundreds of contaminants may be of initial interest, and even small projects can involve a substantial number of contaminants. With multiple assessments common, attention to effectiveness and efficiency is important, and integrating fate and toxicity information provides a valuable way to focus the analyses. Fate assessments help identify what forms may be present where and when, while toxicity information indicates what health effects could result if people were exposed. The integration process is illustrated by an application for the Hanford site, to support long-term management decisions for the cesium and strontium capsules. Fate data, health-based benchmarks, and related toxicity information were effectively combined to indicate performance targets for chemicals and radionuclides identified for capsule leachate that could migrate to groundwater. More than 50 relevant benchmarks and toxicity context were identified for 15 of the 17 study contaminants; values for chronic drinking water exposure provided the common basis for selected indicators. For two chemicals, toxicity information was identified from the scientific literature to guide the performance targets. (authors)

  4. Identification of contaminants of concern Columbia River Comprehensive Impact Assessment

    SciTech Connect

    Napier, B.A.; Batishko, N.C.; Heise-Craff, D.A.; Jarvis, M.F.; Snyder, S.F.

    1995-01-01

    The Columbia River Comprehensive Impact Assessment (CRCIA) Project at the Pacific Northwest Laboratory (PNL) is evaluating the current human and ecological risks from contaminants in the Columbia River. The risks to be studied are those attributable to past and present activities on the Hanford Site. The Hanford Site is located in southcentral Washington State near the town of Richland. Human risk from exposure to radioactive and hazardous materials will be addressed for a range of river use options. Ecological risk will be evaluated relative to the health of the current river ecosystem. The overall purpose of the project is to determine if enough contamination exists in the Columbia River to warrant cleanup actions under applicable environmental regulations. This report documents an initial review, from a risk perspective, of the wealth of historical data concerning current or potential contamination in the Columbia River. Sampling data were examined for over 600 contaminants. A screening analysis was performed to identify those substances present in such quantities that they may pose a significant human or ecological risk. These substances will require a more detailed analysis to assess their impact on humans or the river ecosystem.

  5. Toxicity assessment of contaminated soils from an antitank firing range.

    PubMed

    Robidoux, Pierre Yves; Gong, Ping; Sarrazin, Manon; Bardai, Ghalib; Paquet, Louise; Hawari, Jalal; Dubois, Charles; Sunahara, Geoffrey I

    2004-07-01

    Explosives are released into the environment at production and processing facilities, as well as through field use. These compounds may be toxic at relatively low concentrations to a number of ecological receptors. A toxicity assessment was carried out on soils from an explosive-contaminated site at a Canadian Forces Area Training Center. Toxicity studies on soil organisms using endpoints such as microbial processes (potential nitrification activity, dehydrogenase activity, substrate-induced respiration, basal respiration), plant seedling and growth (Lactuca sativa and Hordeum vulgare), and earthworm (Eisenia andrei) growth and reproduction were carried out. Results showed that 1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane (HMX) was the principal polynitro-organic compound measured in soils. Soils from the contaminated site decreased microbial processes and earthworm reproduction; whereas plant growth was not significantly reduced. Toxicity to aquatic organisms and genotoxicity were also assessed on soil elutriates using Microtox (Vibrio fischeri), growth inhibition of algae (Selenastrum capricornutum), and SOS Chromotest (Escherichia coli). Results indicated that soil elutriates were generally not toxic to bacteria (Microtox) and algae. However, genotoxicity was found in a number of soil elutriate samples. Thus, the explosive-contaminated soils from the antitank firing range may represent a hazard for the soil organisms. Nevertheless, the global toxicity might have partially resulted from HMX as well as from other (not identified) contaminants such as heavy metals. PMID:15223256

  6. 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…

  7. Z306 molecular contamination ad hoc committee results

    NASA Technical Reports Server (NTRS)

    Golden, Johnny L.

    1992-01-01

    LDEF external surfaces which did not receive significant amounts of atomic oxygen were observed to be coated with a brown contamination, apparently the result of a condensed organic residue darkened due to UV radiation exposure. During the initial Materials Special Investigation Group (MSIG) Meeting after LDEF deintegration, held in Seattle - July 1990, this organic contamination was the subject of much discussion. The amount of contamination was thought to be significant and its source was immediately believed to be the Z306 black thermal control coating used to coat the entire inner surface of LDEF. Due to the size of the structure, it was not feasible to bake-out the coating. However, initial data on the contamination film was confusing in that significant amounts of silicon was observed by several different researchers. Silicon (from silicone) was not expected to be a potential outgassing product of the Z306 polyurethane coating. To investigate the connection between external contamination and the interior paint, a MSIG ad hoc committee was formed.

  8. Importance of stationarity for geostatistical assessment of environmental contamination

    SciTech Connect

    Dagdelen, K.; Turner, A.K.

    1996-12-31

    This paper describes a geostatistical case study to assess TCE contamination from multiple point sources that is migrating through the geologically complex conditions with several aquifers. The paper highlights the importance of the stationarity assumption by demonstrating how biased assessments of TCE contamination result when ordinary kriging of the data that violates stationarity assumptions. Division of the data set into more homogeneous geologic and hydrologic zones improved the accuracy of the estimates. Indicator kriging offers an alternate method for providing a stochastic model that is more appropriate for the data. Further improvement in the estimates results when indicator kriging is applied to individual subregional data sets that are based on geological considerations. This further enhances the data homogeneity and makes use of stationary model more appropriate. By combining geological and geostatistical evaluations, more realistic maps may be produced that reflect the hydrogeological environment and provide a sound basis for future investigations and remediation.

  9. Assessment of bacterial contamination in the Bear Creek Floatway, 1988

    SciTech Connect

    Springston, G.L.; Milligan, J.D.

    1988-11-01

    To evaluate the closure status of the floatway, TVA began further monitoring of Bear Creek Floatway to assess the health implications of new criteria relative to fecal coliform and fecal streptococcal contamination. Data were collected for fecal coliform, fecal streptococci, enterococci, and Escherichia coli. Data collection began in April 1984. Results and evaluation of data from May 1985 to July 1986 are reported herein. 6 refs., 3 figs., 3 tabs.

  10. 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. PMID:27441860

  11. Ecological risk assessment for river sediments contaminated by creosote

    SciTech Connect

    Pastorok, R.A.; Sampson, J.R.; Jacobson, M.A. ); Peek, D.C. )

    1994-12-01

    An ecological risk assessment was conducted for sediments of the lower Willamette River near a wood-treatment (creosote) facility. Both surface ad subsurface sediments near the facility are contaminated by polycyclic aromatic hydrocarbons (PAHs). Limited contamination of sediments by dioxins/furans, chlorinated phenols, and arsenic was also observed. Sediment bioassays based on amphipod (Hyalella azteca) mortality and Microtox[reg sign] (Photobacterium phosphoreum) bioluminescence showed toxicity within approximately 300 ft of the shoreline, with a highly toxic area (i.e., possible acute lethal effects in sedentary benthic species) near a dock used for creosote off-loading. The relatively low concentrations of contaminants measured in crayfish muscle tissue and the absence of serious lesions in livers of large-scale sucker collected near the site suggest that excess risk to mobile species from chronic contamination is low. Cursory observations indicate that acute toxic effects on crayfish may be associated with creosote seeps. There is no evidence of adverse biological effects throughout most of the main channel of the river. Evaluation of sediment chemistry data for PAHs relative to available sediment-quality criteria proposed by the US Environmental Protection Agency supports this conclusion.

  12. 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…

  13. 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. PMID:27155931

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  15. 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

  16. TXRF analysis of soils and sediments to assess environmental contamination.

    PubMed

    Bilo, Fabjola; Borgese, Laura; Cazzago, Davide; Zacco, Annalisa; Bontempi, Elza; Guarneri, Rita; Bernardello, Marco; Attuati, Silvia; Lazo, Pranvera; Depero, Laura E

    2014-12-01

    Total reflection x-ray fluorescence spectroscopy (TXRF) is proposed for the elemental chemical analysis of crustal environmental samples, such as sediments and soils. A comparative study of TXRF with respect to flame atomic absorption spectroscopy and inductively coupled plasma optical emission spectroscopy was performed. Microwave acid digestion and suspension preparation methods are evaluated. A good agreement was found among the results obtained with different spectroscopic techniques and sample preparation methods for Cr, Mn, Fe, Ni, Cu, and Zn. We demonstrated that TXRF is suitable for the assessment of environmental contamination phenomena, even if the errors for Pb, As, V, and Ba are ingent. PMID:24122164

  17. Mercury contamination and exposure assessment of fishery products in Korea.

    PubMed

    Yang, Hye-Ran; Kim, Na-Young; Hwang, Lae-Hong; Park, Ju-Sung; Kim, Jung-Hun

    2015-01-01

    In this study, total (T-Hg) and methyl mercury (Me-Hg) contamination was investigated in fishery products including canned fish, fish sauces, dried bonito and frozen tuna sashimi, collected from retail markets in Korea, to assess dietary exposure. Direct mercury analyser and gas chromatography-electron captured detector were employed to measure T-Hg and Me-Hg, respectively. The highest T-Hg and Me-Hg contamination was present in tuna sashimi, followed by dried bonito, respectively. Canned tuna showed more frequent detection and higher content than other canned fishery products. The weekly exposure estimate indicates that exposure to mercury from fishery products is safe, showing 2.59% provisional tolerable weekly intake (PTWI) for T-Hg, 1.82% PTWI for Me-Hg and 4.16% reference dose for Me-Hg. However, it should be addressed to monitor the mercury contamination in fish and fishery products regularly, to safeguard vulnerable population such as children, to limit intake of these food products. PMID:25249274

  18. 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.

  19. 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.

  20. Molecular line contamination in the SCUBA-2 450 and 850 μm continuum data

    NASA Astrophysics Data System (ADS)

    Drabek, E.; Hatchell, J.; Friberg, P.; Richer, J.; Graves, S.; Buckle, J. V.; Nutter, D.; Johnstone, D.; Di Francesco, J.

    2012-10-01

    Observations of the dust emission using millimetre/submillimetre bolometer arrays can be contaminated by molecular line flux, such as flux from 12CO. As the brightest molecular line in the submillimetre, it is important to quantify the contribution of CO flux to the dust continuum bands. Conversion factors were used to convert molecular line integrated intensities to flux detected by bolometer arrays in mJy beam-1. These factors were calculated for 12CO line integrated intensities to the SCUBA-2 850 and 450 μm bands. The conversion factors were then applied to HARP 12CO 3-2 maps of NGC 1333 in the Perseus complex and NGC 2071 and NGC 2024 in the Orion B molecular cloud complex to quantify the respective 12CO flux contribution to the 850 μm dust continuum emission. Sources with high molecular line contamination were analysed in further detail for molecular outflows and heating by nearby stars to determine the cause of the 12CO contribution. The majority of sources had a 12CO 3-2 flux contribution under 20 per cent. However, in regions of molecular outflows, the 12CO can dominate the source dust continuum (up to 79 per cent contamination) with 12CO fluxes reaching ˜68 mJy beam-1.

  1. 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.

  2. Food-chain contamination evaluations in ecological risk assessments

    SciTech Connect

    Linder, G.

    1994-12-31

    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 relatively 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.

  3. 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...

  4. 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...

  5. 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...

  6. Baseline risk assessment of ground water contamination at the Uranium Mill Tailings Site in Lakeview, Oregon

    SciTech Connect

    Not Available

    1994-10-01

    This Baseline Risk Assessment of Ground Water Contamination at the Uranium Mill Tailings Site in Lake view, Oregon evaluates potential impacts to public health or the environment resulting from ground water contamination at the former uranium mill processing site.

  7. 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...

  8. Assessment of basic contamination withstand voltage characteristics of polymer insulators

    SciTech Connect

    Matsuoka, R.; Shinokubo, H.; Kondo, K.; Mizuno, Y.; Naito, K.; Fujimura, T.; Terada, T.

    1996-10-01

    An artificial contamination method for hydrophobic polymer insulators was newly developed, which can provide a uniform contaminant layer similar to the natural one neither by damaging the polymer surface nor by adding any chemical agent to the conventional contamination slurry. Using this method, basic contamination withstand voltage characteristics of polymer insulators were investigated comparing with those of porcelain insulators. The results show that although hydrophobic withstand voltage characteristics critical reduction of withstand voltage occurs sometimes under rapid and heavy wetting and contamination conditions.

  9. MOLECULAR-LEVEL PROCESS GOVERNING THE INTERACTION OF CONTAMINANTS WITH IRON AND MANGANESE OXIDES

    EPA Science Inventory

    Many of the inorganic and organic contaminants present in sediments at DOE sites can bealtered or destroyed by reduction and oxidation (redox) reactions occurring at mineral surfaces. A fundamental understanding of such redox processes provided by molecular-level studies on stru...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  11. 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. PMID:27149560

  12. 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...

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

    PubMed

    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

  14. 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

  15. Alpha contamination assessment for D&D activities: Technology overview

    SciTech Connect

    Conaway, J.G.; Rawool-Sullivan, M.W.; MacArthur, D.W.

    1996-02-01

    Instruments based on the principle of Long-Range Alpha Detection (LRAD) detect the ions created in ambient air by Ionizing radiation, particularly alpha radiation, interacting with air molecules. Using either an electrostatic field or forced convection, these ions can be transported to a detection grid where the ions produce a small current that is measured with a sensitive electrometer. LRAD-based instruments can give separate, simultaneous measurements of alpha-emitting solids and inert radioactive gases such as radon. LRAD-based instruments assess surface contamination on an entire object or large surface area in a single, rapid measurement, including relatively inaccessible areas such as interior surfaces of pipes and process equipment. The LRAD concept is well proven and has been developed into a range of different radiation detection devices. This paper presents an overview of the technology, while several associated papers explore specific applications in greater detail.

  16. Assessment of natural background levels in potentially contaminated coastal aquifers.

    PubMed

    Molinari, A; Chidichimo, F; Straface, S; Guadagnini, A

    2014-04-01

    The estimation of natural background levels (NBLs) of dissolved concentrations of target chemical species in subsurface reservoirs relies on a proper assessment of the effects of forcing terms driving flow and transport processes taking place within the system and whose dynamics drive background concentration values. We propose coupling methodologies based on (a) global statistical analyses and (b) numerical modeling of system dynamics to distinguish between the impacts of different types of external forcing components influencing background concentration values. We focus on the joint application of a statistical methodology based on Component Separation and experimental/numerical modeling studies of groundwater flow and transport for the NBL estimation of selected chemical species in potentially contaminated coastal aquifers. We consider a site which is located in Calabria, Italy, and constitutes a typical example of a Mediterranean coastal aquifer which has been subject to intense industrial development. Our study is keyed to the characterization of NBLs of manganese and sulfate and is geared to the proper identification of the importance of a natural external forcing (i.e., seawater intrusion) on NBL assessment. Results from the Component Separation statistical approach are complemented by numerical simulations of the advective-dispersive processes that could influence the distribution of chemical species (i.e., sulfate) within the system. Estimated NBLs for manganese are consistent with the geochemical composition of soil samples. While Component Separation ascribes the largest detected sulfate concentrations to anthropogenic sources, our numerical modeling analysis suggests that they are mainly related to the natural process of seawater intrusion. Our results indicate that the use of statistical methodologies in complex groundwater systems should be assisted by a detailed characterization of the dynamics of natural (and/or induced) processes to distinguish

  17. RISK ASSESSMENT METHODOLOGY FOR DETERMINING GROUNDWATER CONTAMINATION FROM LANDFILL SLUDGE

    EPA Science Inventory

    Contaminant concentration criteria are required to prevent contaminant infiltration from leading to conditions which exceed health criteria. A methodology of groundwater has been described which may be used to select those criteria and quantify concentrations associated with plac...

  18. Assessing Molecular Dynamics Simulations with Solvatochromism Modeling.

    PubMed

    Schwabe, Tobias

    2015-08-20

    For the modeling of solvatochromism with an explicit representation of the solvent molecules, the quality of preceding molecular dynamics simulations is crucial. Therefore, the possibility to apply force fields which are derived with as little empiricism as possible seems desirable. Such an approach is tested here by exploiting the sensitive solvatochromism of p-nitroaniline, and the use of reliable excitation energies based on approximate second-order coupled cluster results within a polarizable embedding scheme. The quality of the various MD settings for four different solvents, water, methanol, ethanol, and dichloromethane, is assessed. In general, good agreement with the experiment is observed when polarizable force fields and special treatment of hydrogen bonding are applied. PMID:26220273

  19. 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. PMID:23123114

  20. Ecotoxicological and analytical assessment of hydrocarbon-contaminated soils and application to ecological risk assessment

    SciTech Connect

    Saterbak, A.; Toy, R.J.; Wong, D.C.L.; McMain, B.J.; Williams, M.P.; Dorn, P.B.; Brzuzy, L.P.; Chai, E.Y.; Salanitro, J.P.

    1999-07-01

    Ecotoxicological assessments of contaminated soil aim to understand the effect of introduced chemicals on the soil flora and fauna. Ecotoxicity test methods were developed and conducted on hydrocarbon-contaminated soils and on adjacent uncontaminated control soils from eight field locations. Tests included 7-d, 14-d, and chronic survival tests and reproduction assays for the earthworm (Eisenia fetida) and seed germination, root length, and plant growth assays for corn, lettuce, mustard, and wheat. Species-specific responses were observed with no-observed effect concentrations (NOECs) ranging from <1 to 100% contaminated soil. The 14-d earthworm survival NOEC was equal to or greater than the reproduction NOEC values for numbers of cocoons and juveniles, which were similar to one another. Cocoon and juvenile production varied among the control soils. Germination and root length NOECs for mustard and lettuce were less than NOECs for corn and wheat. Root length NOECs were similar to or less than seed germination NOECs. Statistically significant correlations for earthworm survival and seed germination as a function of hydrocarbon measurements were found. The 14-d earthworm survival and the seed germination tests are recommended for use in the context of a risk-based framework for the ecological assessment of contaminated sites.

  1. 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...

  2. 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

  3. Molecular-Level Processes Governing the Interaction of Contaminants with Iron and Manganese Oxides - Final Report

    SciTech Connect

    Brown Jr., G. E.; Chambers, S. A.

    1999-10-31

    Many of the inorganic and organic contaminants present in sediments at DOE sites can be altered or destroyed by reduction and oxidation (redox) reactions occurring at mineral surfaces. A fundamental understanding of such redox processes provided by molecular-level studies on structurally and compositionally well-defined mineral surfaces will lead to: (i) improved models of contaminant fate and transport in geochemical systems, and (ii) optimized manipulation of these processes for remediation purposes. To contribute to this understanding, we will study, both experimentally and theoretically, redox processes involving three important contaminants - chromate ion, carbon tetrachloride, and trichloroethene TCE, on the following iron and manganese oxides - hematite, magnetite, maghemite, and pyrolusite. These oxides and their hydroxylated analogs commonly occur as coatings on minerals or as interfaces in the subsurface environment. Single-crystal surfaces of these oxides will be synthesized in carefully controlled fashion by molecular beam epitaxy. These surfaces, as well as high surface are powdered samples of these oxides, will be used in spectroscopic and kinetic experiments in both aqueous and gas phases. Our goal is to identify products and to determine the kinetics and mechanisms of surface-catalyzed redox reaction of Cr(VI) and CR(III), and the reductive dechlorination of carbon tetrachloride and TCE. The combination of theory and experiment will provide the base information needed to scale from the molecular level to the microscopic grain level minerals.

  4. Assessment of lead bioaccessibility in peri-urban contaminated soils.

    PubMed

    Smith, Euan; Weber, John; Naidu, Ravi; McLaren, Ronald G; Juhasz, Albert L

    2011-02-15

    Lead (Pb) bioaccessibility was assessed in a range of peri-urban soils (n=31) with differing sources of Pb contamination, including shooting range soils, and soils affected by incinerator, historical fill, mining/smelting, and gasworks activities. A gossan soil sample was also included. Lead bioaccessibility was determined using both gastric and intestinal phases of the SBRC in vitro assay and in vitro data was then incorporated into in vivo-in vitro regression equations to calculate Pb relative bioavailability. Lead bioaccessibility ranged from 26.8-105.2% to 5.5-102.6% for gastric and intestinal phase extractions respectively. Generally, Pb bioaccessibility was highest in the shooting range soils and lowest in the gossan soil. Predictions of relative Pb bioavailability derived from in vitro data were comparable for shooting ranges soils, but highly variable for the other soils examined. For incinerator, historical fill, gasworks and gossan soils, incorporating in vitro gastric data into the in vivo-in vitro regression equation resulting in more conservative Pb relative bioavailability values than those derived using the intestinal in vitro data. PMID:21115224

  5. Toxicity Assessment of Contaminated Soils of Solid Domestic Waste Landfill

    NASA Astrophysics Data System (ADS)

    Pasko, O. A.; Mochalova, T. N.

    2014-08-01

    The paper delivers the analysis of an 18-year dynamic pattern of land pollutants concentration in the soils of a solid domestic waste landfill. It also presents the composition of the contaminated soils from different areas of the waste landfill during its operating period. The authors calculate the concentrations of the following pollutants: chrome, nickel, tin, vanadium, lead, cuprum, zinc, cobalt, beryllium, barium, yttrium, cadmium, arsenic, germanium, nitrate ions and petrochemicals and determine a consistent pattern of their spatial distribution within the waste landfill area as well as the dynamic pattern of their concentration. Test-objects are used in experiments to make an integral assessment of the polluted soil's impact on living organisms. It was discovered that the soil samples of an animal burial site are characterized by acute toxicity while the area of open waste dumping is the most dangerous in terms of a number of pollutants. This contradiction can be attributed to the synergetic effect of the polluted soil, which accounts for the regularities described by other researchers.

  6. Surface Water Contamination Risk Assessment Modeled by Fuzzy-WRASTIC.

    PubMed

    Alavipoor, Fatemeh Sadat; Ghorbaninia, Zahra; Karimi, Saeed; Jafari, Hamidreza

    2016-07-01

    This research provides a Fuzzy-WRASTIC new model for water resource contamination risk assessment in a GIS (Geographic Information System) environment. First, this method setting in a multi-criteria evaluation framework (MCE) reviewed and mapped the sub criteria of every above-mentioned criterion. Then, related sub-layers were phased by the observance of GIS environment standards. In the next step, first the sub-layers were combined together, next the modeling of pollution risk status was done by utilizing a fuzzy overlay method and applying the OR, AND, SUM, PRODUCT and GAMMA operators by using WLC (Weighted Linear Combination) method and providing weights in the WRASTIC model. The results provide the best combination of modeling and the percentages of its risk categories of low, medium, high and very high, which are respectively 1.8, 14.07, 51.43 and 32.7. More areas have severe risk due to the unbalanced arrangement and compact of land uses around the compact surface water resources. PMID:27329055

  7. 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...

  8. Characterization and risk assessment of PAH-contaminated river sediment by using advanced multivariate methods.

    PubMed

    Wang, Yeuh-Bin; Liu, Chen-Wuing; Kao, Yu-Hsuan; Jang, Cheng-Shin

    2015-08-15

    This study applied advanced multivariate methods and risk assessment to evaluate the characteristics of polycyclic aromatic hydrocarbons (PAHs) in the sediment of the severely polluted Erjen River in Taiwan. High-molecular-weight PAHs (HPAHs) dominated in the rainy season. The ecological risk of PAHs in the sediment was low, whereas the total health risk through ingestion and dermal contact was considerably high. The SOM (self-organizing map) analysis clustered the datasets of PAH-contaminated sediment into five groups with similar concentration levels. Factor analysis identified major factors, namely coal combustion, traffic, petrogenic, and petrochemical industry factors, accounting for 88.67% of the variance in the original datasets. The major tributary and the downstream of the river were identified as PAH-contamination hotspots. The PMF (positive matrix factorization) was combined with toxicity assessment to estimate the possible apportionment of sources and the associated toxicity. Spills of petroleum-related products, vehicle exhaust, coal combustion, and exhaust from a petrochemical industry complex constituted respectively 12%, 6%, 74%, and 86% of PAHs in the sediment, but contributed respectively 7%, 15%, 22%, and 56% of toxicity posed by PAHs in the sediment. To improve the sediment quality, best management practices should be adopted to eliminate nonpoint sources of PAHs flushed by storm water into the major tributary and the downstream of the Erjen River. The proposed methodologies and results provide useful information on remediating river PAH-contaminated sediment and may be applicable to other basins with similar properties that are experiencing resembled river environmental issues. PMID:25889545

  9. 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…

  10. 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.

  11. A spatially-evaluated methodology for assessing risk to a population from contaminated land.

    PubMed

    Gay, J Rebecca; Korre, Anna

    2006-07-01

    A methodology is proposed which combines quantitative probabilistic human health risk assessment and spatial statistical methods (geostatistics) to produce an assessment of risks to human health from exposure to contaminated land, in a manner which preserves the spatial distribution of risks and provides a measure of uncertainty in the assessment. Maps of soil contaminant levels, which incorporate uncertainty, are produced from sparse sample data using sequential indicator simulation. A real, age-stratified population is mapped across the contaminated area, and intake of soil contaminants by individuals is calculated probabilistically using an adaptation of the Contaminated Land Exposure Assessment (CLEA) model. An abundance of information is contained in results which can be interrogated at the population and individual level, and mapped to provide a powerful visual tool for risk managers, enabling efficient targeting of risk reduction measures to different locations. PMID:16352380

  12. 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...

  13. Assessment of SRS radiological liquid and airborne contaminants and pathways

    SciTech Connect

    Jannik, G.T.

    1997-04-01

    This report compiles and documents the radiological critical-contaminant/critical-pathway analysis performed for SRS. The analysis covers radiological releases to the atmosphere and to surface water, which are the principal media that carry contaminants off site. During routine operations at SRS, limited amounts of radionuclides are released to the environment through atmospheric and/or liquid pathways. These releases potentially result in exposure to offsite people. Though the groundwater beneath an estimated 5 to 10 percent of SRS has been contaminated by radionuclides, there is no evidence that groundwater contaminated with these constituents has migrated offsite (Arnett, 1996). Therefore, with the notable exception of radiological source terms originating from shallow surface water migration into site streams, onsite groundwater was not considered as a potential exposure pathway to offsite people.

  14. Field-based Metabolomics for Assessing Contaminated Surface Waters

    EPA Science Inventory

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

  15. USING SPMDS TO ASSESS MANAGEMENT STRATEGIES FOR PCB CONTAMINATED SEDIMENTS.

    EPA Science Inventory

    Abstract: Dredging in-place treatment, capping and monitored natural recovery, used together or separately are the primary approaches for managing contaminated sediment risks. Understanding how well different approaches work in different environments is critical for choosing an...

  16. Molecular Tools to Monitor Microbial Contaminants During Long-Term Exploration Class Missions

    NASA Astrophysics Data System (ADS)

    Larios-Sanz, M.; Kourentzi, K.; Willson, R.; Pierson, D.; Fox, G.

    Microbial contaminants will inevitably accompany a human crew in our adventures into space. Humans constantly shed large numbers of microorganisms into the environment, and during spaceflight some normally benign microbes may become pathogenic. Concerns about microbial disease during Exploration Class human space missions are particularly important in light of the clinically significant changes that the immune system undergoes during spaceflight. Additionally, increased microbial burdens on closed air and water systems may lead to disease and become dangerous sources of contamination for replacement crews. These microbes might also become a serious threat to regenerative life support systems. The development of a robust system to detect, identify and monitor these contaminants i therefore critical. Wes are currently developing a monitoring system that employs 16S ribosomal RNA sequence information to identify bacterial contaminants at the genus and species level. Despite extensive secondary structure, a large number of regions on the 16S rRNA molecule have been successfully targeted. Probes specific for certain groups, such as "all bacteria", "Gram positives", "Gram negatives", and "enterics", as well as some targeting specific genera and species have been designed and optimized. A set of working probes is now being tested in a variety of solution assays that exploit new and exciting technologies such as molecular beacons and DNA microarrays.

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

    SciTech Connect

    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 determine 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.

  18. Baseline risk assessment of groundwater contamination at the Uranium Mill Tailings Site near Gunnison, Colorado

    SciTech Connect

    Not Available

    1993-12-01

    This Baseline Risk Assessment of Groundwater Contamination at the Uranium Mill Tailings Site Near Gunnison, Colorado evaluates potential impacts to public health or the environment resulting from groundwater contamination at the former uranium mill processing site. The tailings and other contaminated material at this site are being placed in an off-site disposal cell by the US Department of Energy`s (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project. Currently, the UMTRA Project is evaluating groundwater contamination. This is the second risk assessment of groundwater contamination at this site. The first risk assessment was performed primarily to evaluate existing domestic wells. This risk assessment evaluates the most contaminated monitor wells at the processing site. It will be used to assist in determining what remedial action is needed for contaminated groundwater at the site after the tailings are relocated. This risk assessment follows an approach outlined by the US Environmental Protection Agency (EPA). The first step is to evaluate groundwater data collected from monitor wells at the site. Evaluation of these data showed that the main contaminants in the groundwater are cadmium, cobalt, iron, manganese, sulfate, uranium, and some of the products of radioactive decay of uranium.

  19. 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.

  20. A model for the assessment of aquifer contamination potential based on regional geologic framework

    USGS Publications Warehouse

    Soller, D.R.; Berg, R.C.

    1992-01-01

    The texture and three-dimensional framework of geologic materials should be considered in assessments of groundwater's vulnerability to contamination because geology controls the movement of contaminants and groundwater and influences groundwater quality. Contaminants are introduced into, transmitted through, and stored by geologic materials. We present a model that identifies aquifers and ranks sequences of geologic materials by their relative potential for transmitting water and contaminants from land surface. With this basis, the model can be used to assess the potential for contamination of aquifers by surface activities such as landfitling of wastes or application of agricultural chemicals. A regional map of aquifer contamination potential can be generated from the model; it retains the geologic map information intact and available for reinterpretation or other uses. The model was developed using broad, regional map information and is intended to be a general tool for assessing the regional vulnerability of aquifers to contamination. It is not intended for local, site-specific use, but for prioritizing local areas where contamination potential and/or land-use history warrant more detailed assessment or monitoring. Because it provides a regional view of contamination potential, regional patterns or trends of map units should be evaluated, rather than using the map information literally to assess local areas. Methods of applying this model and contamination potential map to groundwater protection and management are currently being studied; research includes an attempt to statistically validate the model with water-quality data, and to identify natural groupings of the ranked contamination potential map units. ?? 1992 Springer-Verlag New York Inc.

  1. An evaluation of the capability of a biolayer interferometry biosensor to detect low-molecular-weight food contaminants.

    PubMed

    McGrath, Terry F; Campbell, Katrina; Fodey, Terry L; O'Kennedy, Richard; Elliott, Christopher T

    2013-03-01

    The safety of our food is an essential requirement of society. One well-recognised threat is that of chemical contamination of our food, where low-molecular-weight compounds such as biotoxins, drug residues and pesticides are present. Low-cost, rapid screening procedures are sought to discriminate the suspect samples from the population, thus selecting only these to be forwarded for confirmatory analysis. Many biosensor assays have been developed as screening tools in food contaminant analysis, but these tend to be electrochemical, fluorescence or surface plasmon resonance based. An alternative approach is the use of biolayer interferometry, which has become established in drug discovery and life science studies but is only now emerging as a potential tool in the analysis of food contaminants. A biolayer interferometry biosensor was assessed using domoic acid as a model compound. Instrument repeatability was tested by simultaneously producing six calibration curves showing replicate repeatability (n = 2) ranging from 0.1 to 6.5 % CV with individual concentration measurements (n = 12) ranging from 4.3 to 9.3 % CV, giving a calibration curve midpoint of 7.5 ng/ml (2.3 % CV (n = 6)). Reproducibility was assessed by producing three calibration curves on different days, giving a midpoint of 7.5 ng/ml (3.4 %CV (n = 3)). It was further shown, using assay development techniques, that the calibration curve midpoint could be adjusted from 10.4 to 1.9 ng/ml by varying assay parameters before the simultaneous construction of three calibration curves in matrix and buffer. Sensitivity of the assay compared favourably with previously published biosensor data for domoic acid. PMID:23338757

  2. 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/...

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

    SciTech Connect

    Murnyak, George; Vandenberg, John; Yaroschak, Paul J.; Williams, Larry; Prabhakaran, Krishnan; Hinz, John

    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 five 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).

  4. 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...

  5. 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...

  6. Emerging contaminants: presentations at the 2009 Toxicology and Risk Assessment Conference.

    PubMed

    Murnyak, George; Vandenberg, John; Yaroschak, Paul J; Williams, Larry; Prabhakaran, Krishnan; Hinz, John

    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 five 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). PMID:21034762

  7. Assessment of contaminants in Dubai coastal region, United Arab Emirates

    NASA Astrophysics Data System (ADS)

    Al-Darwish, H. A.; Abd El-Gawad, E. A.; Mohammed, F. H.; Lotfy, M. M.

    2005-12-01

    Coastal uses and other human activities have inevitably impinged on the Gulf environment; therefore, these regions require continuous monitoring. The investigated area covered the maximum fragments of Dubai coastal region in the Arabian Gulf. The determination of major oxides and trace metal concentrations in Dubai sediments revealed three heavily and moderately contaminated regions. One is in the far northeastern part at Al-Hamriya Sts 1 3 and contaminated by Fe, Cu, Pb, and Zn; the second is in the mid-northeastern part at Dry Docks and contaminated by Cu, Ni, Pb, and Zn; and finally, the third is in the near southwestern part at Dubal and contaminated by Fe, Mg, Cr, Ni, and Zn. Al-Hamriya St 3 represented the highest values of Cu, Pb, and Zn, whereas Dubal exhibited the maximum values of Fe, Mg, Ba, Cr, Mn, Ni, and V. The anthropogenic discharge and natural deposits are the main sources of contamination. In general, all trace and major elements showed the minimal levels at Jebel Ali Sanctuary (Sts 11, 12, 13) except for Sr and Ca, which showed their maximum values. The highest concentrations of Ca and Sr are mainly attributed to carbonate gravel sands and sands, which cover most stations. Each of V and Ni showed negative correlation with TPH, which may be indicated that the source of oil contamination in the region is not related to crude oil but mostly attributable to anthropogenic sources. The significant positive correlation, which was found between trace metals and TOC indicates that organic matter plays an important role in the accumulation of trace metals in case of Cu, Zn, and Pb.

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

    SciTech Connect

    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 both 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.

  9. Accessing indoor fungal contamination using conventional and molecular methods in Portuguese poultries.

    PubMed

    Viegas, C; Malta-Vacas, J; Sabino, R; Viegas, S; Veríssimo, C

    2014-03-01

    Epidemiological studies showed increased prevalence of respiratory symptoms and adverse changes in pulmonary function parameters in poultry workers, corroborating the increased exposure to risk factors, such as fungal load and their metabolites. This study aimed to determine the occupational exposure threat due to fungal contamination caused by the toxigenic isolates belonging to the complex of the species of Aspergillus flavus and also isolates from Aspergillus fumigatus species complex. The study was carried out in seven Portuguese poultries, using cultural and molecular methodologies. For conventional/cultural methods, air, surfaces, and litter samples were collected by impaction method using the Millipore Air Sampler. For the molecular analysis, air samples were collected by impinger method using the Coriolis μ air sampler. After DNA extraction, samples were analyzed by real-time PCR using specific primers and probes for toxigenic strains of the Aspergillus flavus complex and for detection of isolates from Aspergillus fumigatus complex. Through conventional methods, and among the Aspergillus genus, different prevalences were detected regarding the presence of Aspergillus flavus and Aspergillus fumigatus species complexes, namely: 74.5 versus 1.0 % in the air samples, 24.0 versus 16.0 % in the surfaces, 0 versus 32.6 % in new litter, and 9.9 versus 15.9 % in used litter. Through molecular biology, we were able to detect the presence of aflatoxigenic strains in pavilions in which Aspergillus flavus did not grow in culture. Aspergillus fumigatus was only found in one indoor air sample by conventional methods. Using molecular methodologies, however, Aspergillus fumigatus complex was detected in seven indoor samples from three different poultry units. The characterization of fungal contamination caused by Aspergillus flavus and Aspergillus fumigatus raises the concern of occupational threat not only due to the detected fungal load but also because of the

  10. SURROGATE SPECIES IN ASSESSING CONTAMINANT RISK FOR ENDANGERED FISHES, INCLUDING INTERSPECIES TOXICITY CORRELATIONS

    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 accorda...

  11. 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...

  12. Assessment of exposures to fecally-contaminated recreational water

    EPA Science Inventory

    Exposure to fecally-contaminated recreational waters can pose a health risk to swimmers and other recreators. Since 2003, we have interviewed nearly 27,000 respondents at seven beaches impacted by treated sewage discharge. Information was collected about the duration and exposure...

  13. Control and assessment of the hydrocarbon contamination of Ukrainian soils

    NASA Astrophysics Data System (ADS)

    Miroshnichenko, N. N.

    2008-05-01

    Regularities governing the self-purification of soils from oil hydrocarbons, as well as migration of hydrocarbons, and the effect on the water-physical properties and fertility of soils were revealed in a series of experiments. A system of ecological, economic, and reclamation standards was proposed for regulating economic activities in the case of soil contamination with hydrocarbons.

  14. 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.

  15. Cumulative health risk assessment: integrated approaches for multiple contaminants, exposures, and effects

    SciTech Connect

    Rice, Glenn; Teuschler, Linda; MacDonel, Margaret; Butler, Jim; Finster, Molly; Hertzberg, Rick; Harou, Lynne

    2007-07-01

    Available in abstract form only. Full text of publication follows: As information about environmental contamination has increased in recent years, so has public interest in the combined effects of multiple contaminants. This interest has been highlighted by recent tragedies such as the World Trade Center disaster and hurricane Katrina. In fact, assessing multiple contaminants, exposures, and effects has long been an issue for contaminated sites, including U.S. Department of Energy (DOE) legacy waste sites. Local citizens have explicitly asked the federal government to account for cumulative risks, with contaminants moving offsite via groundwater flow, surface runoff, and air dispersal being a common emphasis. Multiple exposures range from ingestion and inhalation to dermal absorption and external gamma irradiation. Three types of concerns can lead to cumulative assessments: (1) specific sources or releases - e.g., industrial facilities or accidental discharges; (2) contaminant levels - in environmental media or human tissues; and (3) elevated rates of disease - e.g., asthma or cancer. The specific initiator frames the assessment strategy, including a determination of appropriate models to be used. Approaches are being developed to better integrate a variety of data, extending from environmental to internal co-location of contaminants and combined effects, to support more practical assessments of cumulative health risks. (authors)

  16. Assessing hazards due to contaminant discharge in coastal waters

    NASA Astrophysics Data System (ADS)

    Churchill, J. H.

    1987-02-01

    Models of contaminant dispersion in the marine environment have mostly sought to determine the mean concentration field. At a location not far from a pollution source, concentration is intermittently high, depending on whether the site is immersed in the concentrated contaminant plume which emanates from the source. At such a locale the probability of immersion, denoted by visitation frequency, is a more meaningful measure of nuisance than mean concentration. Two methods of computing visitation frequency from moored current meter data, each having particular advantages and drawbacks, are presented. One technique estimates visitation frequency from probability distributions of the position and velocity of water parcels originating from the effluent source. The second method entails simulating the configuration and movement of a contaminant plume. Required by both schemes is the plume cross-axial width as a function of time since release. A simple procedure of approximating this using the results of dye diffusion studies is described. These methods are applied to the coastal region off Long Island, New York, where current meter and dye diffusion data are available.

  17. Determining uranium speciation in contaminated soils by molecular spectroscopic methods: Examples from the Uranium in Soils Integrated Demonstration

    SciTech Connect

    Allen, P.G.; Berg, J.M.; Chisholm-Brause, C.J.; Conradson, S.D.; Donohoe, R.J.; Morris, D.E.; Musgrave, J.A.; Tait, C.D.

    1994-03-01

    The US Department of Energy`s former uranium production facility located at Fernald, OH (18 mi NW of Cincinnati) is the host site for an Integrated Demonstration for remediation of uranium-contaminated soils. A wide variety of source terms for uranium contamination have been identified reflecting the diversity of operations at the facility. Most of the uranium contamination is contained in the top {approximately}1/2 m of soil, but uranium has been found in perched waters indicating substantial migration. In support of the development of remediation technologies and risk assessment, we are conducting uranium speciation studies on untreated and treated soils using molecular spectroscopies. Untreated soils from five discrete sites have been analyzed. We have found that {approximately}80--90% of the uranium exists as hexavalent UO{sub 2}{sup 2+} species even though many source terms consisted of tetravalent uranium species such as UO{sub 2}. Much of the uranium exists as microcrystalline precipitates (secondary minerals). There is also clear evidence for variations in uranium species from the microscopic to the macroscopic scale. However, similarities in speciation at sites having different source terms suggest that soil and groundwater chemistry may be as important as source term in defining the uranium speciation in these soils. Characterization of treated soils has focused on materials from two sites that have undergone leaching using conventional extractants (e.g., carbonate, citrate) or novel chelators such as Tiron. Redox reagents have also been used to facilitate the leaching process. Three different classes of treated soils have been identified based on the speciation of uranium remaining in the soils. In general, the effective treatments decrease the total uranium while increasing the ratio of U(IV) to U(VI) species.

  18. Assessing ground-water vulnerability to contamination: Providing scientifically defensible information for decision makers

    USGS Publications Warehouse

    Focazio, Michael J.; Reilly, Thomas E.; Rupert, Michael G.; Helsel, Dennis R.

    2002-01-01

    Throughout the United States increasing demands for safe drinking water and requirements to maintain healthy ecosystems are leading policy makers to ask complex social and scientific questions about how to assess and manage our water resources. This challenge becomes particularly difficult as policy and management objectives require scientific assessments of the potential for ground-water resources to become contaminated from anthropogenic, as well as natural sources of contamination. Assessments of the vulnerability of ground water to contamination range in scope and complexity from simple, qualitative, and relatively inexpensive approaches to rigorous, quantitative, and costly assessments. Tradeoffs must be carefully considered among the competing influences of the cost of an assessment, the scientific defensibility, and the amount of acceptable uncertainty in meeting the objectives of the water-resource decision maker.

  19. 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

  20. Assessing Practical Laboratory Skills in Undergraduate Molecular Biology Courses

    ERIC Educational Resources Information Center

    Hunt, Lynne; Koenders, Annette; Gynnild, Vidar

    2012-01-01

    This study explored a new strategy of assessing laboratory skills in a molecular biology course to improve: student effort in preparation for and participation in laboratory work; valid evaluation of learning outcomes; and students' employment prospects through provision of evidence of their skills. Previously, assessment was based on written…

  1. 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. PMID:25809961

  2. 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.

  3. MERCURY CONTAMINATED MATERIAL DECONTAMINATION METHODS: INVESTIGATION AND ASSESSMENT

    SciTech Connect

    M.A. Ebadian, Ph.D.

    2001-01-01

    Over the years mercury has been recognized as having serious impacts on human health and the environment. This recognition has led to numerous studies that deal with the properties of various mercury forms, the development of methods to quantify and speciate the forms, fate and transport, toxicology studies, and the development of site remediation and decontamination technologies. This report reviews several critical areas that will be used in developing technologies for cleaning mercury from mercury-contaminated surfaces of metals and porous materials found in many DOE facilities. The technologies used for decontamination of water and mixed wastes (solid) are specifically discussed. Many technologies that have recently appeared in the literature are included in the report. Current surface decontamination processes have been reviewed, and the limitations of these technologies for mercury decontamination are discussed. Based on the currently available technologies and the processes published recently in the literature, several processes, including strippable coatings, chemical cleaning with iodine/iodide lixiviant, chemisorbing surface wipes with forager sponge and grafted cotton, and surface/pore fixation through amalgamation or stabilization, have been identified as potential techniques for decontamination of mercury-contaminated metal and porous surfaces. Their potential merits and applicability are discussed. Finally, two processes, strippable coatings and chemical cleaning with iodine/iodide lixiviant, were experimentally investigated in Phase II of this project.

  4. Assessment of combined electro-nanoremediation of molinate contaminated soil.

    PubMed

    Gomes, Helena I; Fan, Guangping; Mateus, Eduardo P; Dias-Ferreira, Celia; Ribeiro, Alexandra B

    2014-09-15

    Molinate is a pesticide widely used, both in space and time, for weed control in rice paddies. Due to its water solubility and affinity to organic matter, it is a contaminant of concern in ground and surface waters, soils and sediments. Previous works have showed that molinate can be removed from soils through electrokinetic (EK) remediation. In this work, molinate degradation by zero valent iron nanoparticles (nZVI) was tested in soils for the first time. Soil is a highly complex matrix, and pollutant partitioning between soil and water and its degradation rates in different matrices is quite challenging. A system combining nZVI and EK was also set up in order to study the nanoparticles and molinate transport, as well as molinate degradation. Results showed that molinate could be degraded by nZVI in soils, even though the process is more time demanding and degradation percentages are lower than in an aqueous solution. This shows the importance of testing contaminant degradation, not only in aqueous solutions, but also in the soil-sorbed fraction. It was also found that soil type was the most significant factor influencing iron and molinate transport. The main advantage of the simultaneous use of both methods is the molinate degradation instead of its accumulation in the catholyte. PMID:24946031

  5. Molecular-level process governing the interaction of contaminants with iron and manganese oxides. 1998 annual progress report

    SciTech Connect

    Chambers, S.A.; Brown, G.E.

    1998-06-01

    'The authors are carrying out a program of research that focuses on the fundamental mechanisms of redox chemistry of contaminants on mineral surfaces. As much of this chemistry in sediments involves the Fe(III)/Fe(II) and Mn(IV)/Mn(II) couples, they are focusing on mineral phases containing these species. The authors are using a variety of experimental probes, along with molecular modeling theory, to determine clean mineral surface structure and morphology, details of the chemisorption and decomposition of water, and the interface structure and redox chemistry of important contaminants such as CrO{sub 4}{sup -2} on these surfaces. Insight gained in this project will aid in the formulation of more accurate and realistic contaminant-surface complexation and contaminant transport models, and may suggest improved remediation strategies for certain kinds of contaminated soil and groundwater.'

  6. 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...

  7. 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...

  8. 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. PMID:23552652

  9. 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...

  10. Molecular contamination effects on the thermal emittance of highly reflective surfaces at cryogenic temperatures

    NASA Astrophysics Data System (ADS)

    Chang, Chien W.

    2002-09-01

    For contamination effects on thermal control surfaces, changes in solar absorptance are the effect noted. Emittance of the surface is not normally affected. The SIRTF (Space InfraRed Telescope Facility) and NGST (Next Generation Space Telescope) spacecraft will fly large low emissivity surfaces (e.g. aluminized Kapton shields and gold mirrors). During the orbital missions, these surfaces will not be exposed to the sun and will be at temperatures less than 150 K. Concern is that a thick molecular film, even water, will cause a change in emittance and results in affecting the thermal performance primarily controlled by emittance alone. Although an emphasis will be placed upon examining the effects on thermal performance for low emissivity surfaces, the effects on optical performance will also be examined because changes of the optical characteristics such as reflectance and scattering are of greater concern for the NGST mission.

  11. 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. PMID:26429550

  12. Baseline risk assessment of ground water contamination at the Uranium Mill Tailings Site near Riverton, Wyoming

    SciTech Connect

    Not Available

    1994-09-01

    This Risk Assessment evaluated potential impacts to public health or the environment caused by ground water contamination at the former uranium mill processing site. In the first phase of the U.S. Department of Energy`s Uranium Mill Tailings Remedial Action (UMTRA) Project, the tailing and other contaminated material at this site were placed in a disposal cell near the Gas Hills Plant in 1990. The second phase of the UMTRA Project is to evaluate ground water contamination. This risk assessment is the first site-specific document to evaluate potential health and environmental risks for the Riverton site under the Ground Water Project; it will help determine whether remedial actions are needed for contaminated ground water at the site.

  13. Heisenberg coupling constant predicted for molecular magnets with pairwise spin-contamination correction

    NASA Astrophysics Data System (ADS)

    Masunov, Artëm E.; Gangopadhyay, Shruba

    2015-12-01

    New method to eliminate the spin-contamination in broken symmetry density functional theory (BS DFT) calculations is introduced. Unlike conventional spin-purification correction, this method is based on canonical Natural Orbitals (NO) for each high/low spin coupled electron pair. We derive an expression to extract the energy of the pure singlet state given in terms of energy of BS DFT solution, the occupation number of the bonding NO, and the energy of the higher spin state built on these bonding and antibonding NOs (not self-consistent Kohn-Sham orbitals of the high spin state). Compared to the other spin-contamination correction schemes, spin-correction is applied to each correlated electron pair individually. We investigate two binuclear Mn(IV) molecular magnets using this pairwise correction. While one of the molecules is described by magnetic orbitals strongly localized on the metal centers, and spin gap is accurately predicted by Noodleman and Yamaguchi schemes, for the other one the gap is predicted poorly by these schemes due to strong delocalization of the magnetic orbitals onto the ligands. We show our new correction to yield more accurate results in both cases.

  14. Low pressure drop airborne molecular contaminant filtration using open-channel networks

    NASA Astrophysics Data System (ADS)

    Dallas, Andrew J.; Ding, Lefei; Joriman, Jon; Zastera, Dustin; Seguin, Kevin; Empson, James

    2006-03-01

    Airborne molecular contamination (AMC) continues to play a very decisive role in the performance of many microelectronic devices and manufacturing processes. Currently, the state of the filtration industry is such that optimum filter life and removal efficiency for AMC is offered by granular filter beds. However, the attributes that make packed beds of adsorbents extremely efficient also impart issues related to elevated filter weight and pressure drop. Most of the low pressure drop AMC filters currently offered tend to be quiet costly and contaminant nonspecific. Many of these low pressure drop filters are simply pleated combinations of various adsorptive and reactive media. On the other hand, low pressure drop filters, such as those designed as open-channel networks (OCNs), can still offer good filter life and removal efficiency, with the additional benefits of significant reductions in overall filter weight and pressure drop. Equally important for many applications, the OCN filters can reconstruct the airflow so as to enhance the operation of a tool or process. For tool mount assemblies and full fan unit filters this can result in reduced fan and blower speeds, which subsequently can provide reduced vibration and energy costs. Additionally, these low pressure drop designs can provide a cost effective way of effectively removing AMC in full fab (or HVAC) filtration applications without significantly affecting air-handling requirements. Herein, we will present a new generation of low pressure drop OCN filters designed for AMC removal in a wide range of applications.

  15. Baseline risk assessment of ground water contamination at the uranium mill tailings site near Canonsburg, Pennsylvania

    SciTech Connect

    Not Available

    1994-09-01

    This baseline risk assessment evaluates potential impacts to public health and the environment resulting from ground water contamination from past activities at the former uranium processing site in Canonsburg, Pennsylvania. The US Department of Energy Uranium Mill Tailings Remedial Action (UMTRA) Project has placed contaminated material from this site in an on-site disposal cell. Currently, the UMTRA Project is evaluating ground water contamination. This risk assessment is the first document specific to this site for the UMTRA Ground Water Project. Currently, no domestic or drinking water well tap into contaminated ground water of the two distinct ground water units: the unconsolidated materials and the bedrock. Because there is no access, no current health or environmental risks are associated with the direct use of the contaminated ground water. However, humans and ecological organisms could be exposed to contaminated ground water if a domestic well were to be installed in the unconsolidated materials in that part of the site being considered for public use (Area C). The first step is evaluating ground water data collected from monitor wells at the site. For the Canonsburg site, this evaluation showed the contaminants in ground water exceeding background in the unconsolidated materials in Area C are ammonia, boron, calcium, manganese, molybdenum, potassium, strontium, and uranium.

  16. Contamination control and plume assessment of low-energy thrusters

    NASA Technical Reports Server (NTRS)

    Scialdone, John J.

    1993-01-01

    Potential contamination of a spacecraft cryogenic surface by a xenon (Xe) ion generator was evaluated. The analysis involves the description of the plume exhausted from the generator with its relative component fluxes on the spacecraft surfaces, and verification of the conditions for condensation, adsorption, and sputtering at those locations. The data describing the plume fluxes and their effects on surfaces were obtained from two sources: the tests carried out with the Xe generator in a small vacuum chamber to indicate deposits and sputter on monitor slides; and the extensive tests with a mercury (Hg) ion thruster in a large vacuum chamber. The Hg thruster tests provided data on the neutrals, on low-energy ion fluxes, on high-energy ion fluxes, and on sputtered materials at several locations within the plume.

  17. 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, N. M.; 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.

  18. Ecological Risk Assessment of a Metal-Contaminated Area in the Tropics. Tier II: Detailed Assessment

    PubMed Central

    Niemeyer, Júlia Carina; Moreira-Santos, Matilde; Ribeiro, Rui; Rutgers, Michiel; Nogueira, Marco Antonio; da Silva, Eduardo Mendes; Sousa, José Paulo

    2015-01-01

    This study presents data on the detailed evaluation (tier 2) of a site-specific ecological risk assessment (ssERA) in a former smelter area contaminated with metals (Santo Amaro, Bahia, Brazil). Combining information from three lines of evidence (LoE), chemical (ChemLoE), ecotoxicological (EcotoxLoE) and ecological (EcoLoE), in the Triad approach, integrated risk values were calculated to rank sites and confirm the potential risk disclosed with tier 1. Risk values were calculated for the habitat and for the retention functions in each sampling point. Habitat function included the ChemLoE calculated from total metal concentrations. The EcotoxLoE was based on reproduction tests with terrestrial invertebrates (Folsomia candida, Enchytraeus crypticus, Eisenia andrei), shoot length and plant biomass (Avena sativa, Brassica rapa). For the EcoLoE, ecological parameters (microbial parameters, soil invertebrate community, litter breakdown) were used to derive risk values. Retention function included the ChemLoE, calculated from extractable metal concentrations, and the EcotoxLoE based on eluate tests with aquatic organisms (Daphnia magna reproduction and Pseudokirchneriella subcapitata growth). Results related to the habitat function indicated that the metal residues are sufficient to cause risk to biota, while the low metal levels in extracts and the general lack of toxicity in aquatic tests indicated a high soil retention capacity in most sampling points. Integrated risk of tier 2 showed the same trend of tier 1, suggesting the need to proceed with remediation actions. The high risk levels were related to direct toxicity to organisms and indirect effects, such as failure in the establishment of vegetation and the consequent loss of habitat quality for microorganisms and soil fauna. This study shed some light on the selection of tools for the tier 2 of an ssERA in tropical metal-contaminated sites, focusing on ecological receptors at risk and using available chemical

  19. Ecological Risk Assessment of a Metal-Contaminated Area in the Tropics. Tier II: Detailed Assessment.

    PubMed

    Niemeyer, Júlia Carina; Moreira-Santos, Matilde; Ribeiro, Rui; Rutgers, Michiel; Nogueira, Marco Antonio; da Silva, Eduardo Mendes; Sousa, José Paulo

    2015-01-01

    This study presents data on the detailed evaluation (tier 2) of a site-specific ecological risk assessment (ssERA) in a former smelter area contaminated with metals (Santo Amaro, Bahia, Brazil). Combining information from three lines of evidence (LoE), chemical (ChemLoE), ecotoxicological (EcotoxLoE) and ecological (EcoLoE), in the Triad approach, integrated risk values were calculated to rank sites and confirm the potential risk disclosed with tier 1. Risk values were calculated for the habitat and for the retention functions in each sampling point. Habitat function included the ChemLoE calculated from total metal concentrations. The EcotoxLoE was based on reproduction tests with terrestrial invertebrates (Folsomia candida, Enchytraeus crypticus, Eisenia andrei), shoot length and plant biomass (Avena sativa, Brassica rapa). For the EcoLoE, ecological parameters (microbial parameters, soil invertebrate community, litter breakdown) were used to derive risk values. Retention function included the ChemLoE, calculated from extractable metal concentrations, and the EcotoxLoE based on eluate tests with aquatic organisms (Daphnia magna reproduction and Pseudokirchneriella subcapitata growth). Results related to the habitat function indicated that the metal residues are sufficient to cause risk to biota, while the low metal levels in extracts and the general lack of toxicity in aquatic tests indicated a high soil retention capacity in most sampling points. Integrated risk of tier 2 showed the same trend of tier 1, suggesting the need to proceed with remediation actions. The high risk levels were related to direct toxicity to organisms and indirect effects, such as failure in the establishment of vegetation and the consequent loss of habitat quality for microorganisms and soil fauna. This study shed some light on the selection of tools for the tier 2 of an ssERA in tropical metal-contaminated sites, focusing on ecological receptors at risk and using available chemical

  20. Passive sampling in contaminated sediment assessment: building consensus to improve decision making.

    PubMed

    Parkerton, Thomas F; Maruya, Keith A

    2014-04-01

    Contaminated sediments pose an ongoing, pervasive, global challenge to environmental managers, because sediments can reflect a legacy of pollution that can impair the beneficial uses of water bodies. A formidable challenge in assessing the risks of contaminated sediments has been the elucidation and measurement of contaminant bioavailability, expressed as the freely dissolved concentration (Cfree ) in interstitial water, which serves as a surrogate measure of the substances' chemical activity. Recent advances in passive sampling methods (PSMs) enable Cfree of sediment-associated contaminants to be quantified at trace levels, thereby overcoming current limitations of predictive models. As a result, PSMs afford the opportunity for a paradigm shift from traditional practice that can effectively reduce uncertainty in risk assessment and bolster confidence in the science used to support management of contaminated sediments. This paper provides a brief overview of the 5 subsequent papers in this series that review literature on PSM use in sediments for both organic and metal(loid) contaminants, outline the technical rationale for using PSMs as a preferred basis for risk assessment over conventional chemical analyses, describe practical considerations for and uncertainties associated with laboratory and field deployment of PSMs, discuss management application of PSMs, including illustrative case studies in which PSMs have been used in decision making, and highlight future research and communication needs. PMID:24142815

  1. Guidance for treatment of variability and uncertainty in ecological risk assessments of contaminated sites

    SciTech Connect

    1998-06-01

    Uncertainty is a seemingly simple concept that has caused great confusion and conflict in the field of risk assessment. This report offers guidance for the analysis and presentation of variability and uncertainty in ecological risk assessments, an important issue in the remedial investigation and feasibility study processes. This report discusses concepts of probability in terms of variance and uncertainty, describes how these concepts differ in ecological risk assessment from human health risk assessment, and describes probabilistic aspects of specific ecological risk assessment techniques. The report ends with 17 points to consider in performing an uncertainty analysis for an ecological risk assessment of a contaminated site.

  2. 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

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

    PubMed

    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

  4. Assessment of bacterial contamination of drinking water provided to mice.

    PubMed

    Haist, Carrie; Cadillac, Joan; Dysko, Robert

    2004-11-01

    The objective of this study was to evaluate whether an 240-ml water bottle provided to individually housed mice would remain potable for a 2-week interval (based on absence of coliforms). The study used inbred C57BL/6 mice and CB6F1 x C3D2F1 hybrid mice. Test groups were assigned to minimize the variables of strain, caging type (non-ventilated static versus ventilated) and building location. A 3-cc sample of drinking water was removed aseptically from the bottles and vacuum-filtered using a 250-ml filter funnel with a 0.45-mum pore size. The membrane filter was removed using sterile forceps and placed on a blood agar plate for 10 min. The plate was streaked and incubated at 37 degrees C for 5 days. The plates were observed daily, and if growth had occurred, further testing was done to determine specific organisms. Of the 148 samples only 23 had any bacterial growth. Typical bacteria were unspeciated gram-positive bacilli and Staphylococcus, Micrococcus, Streptococcus, and Pantoea species. The absence of coliforms and low percentage of bacterial contamination suggest that drinking water will remain potable for 2 weeks when supplied to an individual mouse. PMID:15636548

  5. ASSESSMENT OF ALLERGIC IMMUNE RESPONSES TO INDOOR AIR FUNGAL CONTAMINANTS

    EPA Science Inventory

    We are using a mouse model to assess immune and inflammatory responses as well as changes in respiratory function and pathology characteristic of allergic asthma to fungal extracts M. anisopliae (MACA), S. chartarum (SCE), and P. chrysogenum (PCE). This model will be useful to a...

  6. A tiered assessment framework to evaluate human health risk of contaminated sediment.

    PubMed

    Greenfield, Ben K; Melwani, Aroon R; Bay, Steven M

    2015-07-01

    For sediment contaminated with bioaccumulative pollutants (e.g., PCBs and organochorine pesticides), human consumption of seafood that contain bioaccumulated sediment-derived contaminants is a well-established exposure pathway. Historically, regulation and management of this bioaccumulation pathway has focused on site-specific risk assessment. The state of California (United States) is supporting the development of a consistent and quantitative sediment assessment framework to aid in interpreting a narrative objective to protect human health. The conceptual basis of this framework focuses on 2 key questions: 1) do observed pollutant concentrations in seafood from a given site pose unacceptable health risks to human consumers? and 2) is sediment contamination at a site a significant contributor to seafood contamination? The first question is evaluated by interpreting seafood tissue concentrations at the site, based on health risk calculations. The second question is evaluated by interpreting site-specific sediment chemistry data using a food web bioaccumulation model. The assessment framework includes 3 tiers (screening assessment, site assessment, and refined site assessment), which enables the assessment to match variations in data availability, site complexity, and study objectives. The second and third tiers use a stochastic simulation approach, incorporating information on variability and uncertainty of key parameters, such as seafood contaminant concentration and consumption rate by humans. The framework incorporates site-specific values for sensitive parameters and statewide values for difficult to obtain or less sensitive parameters. The proposed approach advances risk assessment policy by incorporating local data into a consistent region-wide problem formulation, applying best available science in a streamlined fashion. PMID:25641876

  7. MOLECULAR PROFILING OF MICROBIAL COMMUNITIES FROM CONTAMINATED SOURCES: USE OF SUBTRACTIVE CLONING METHODS AND RDNA SPACER SEQUENCES

    EPA Science Inventory

    This research addresses the development and testing of molecular methods that will allow rapid characterization of microbial communities in perturbed or contaminated ecosystems. The major objective of the research is to provide appropriate sequences and to assemble a high-density...

  8. Using a temperature-controlled quartz crystal microbalance in a space equipment cleanroom to monitor molecular contamination

    NASA Technical Reports Server (NTRS)

    Mitchell, William J.

    1994-01-01

    There is a need for continuous monitoring for molecular contamination in clean rooms where spaceflight equipment is assembled, integrated, and tested to insure that contamination budgets are met. The TQCM (temperature-controlled quartz crystal microbalance) can be used to provide both a real time warning and a cumulative measurement of molecular contamination. It has advantages over the other measurement methods such as witness mirrors, NVR (non-volatile residue) plates, and gas analyzers. A comparison of the TQCM sensitivity and ease of operations is made with the other methods. The surface acoustic wave microbalance (SAW), a newly developed instrument similar to TQCM, is considered in the comparison. An example is provided of TQCM use at Goddard Space Flight Center when the Wide Field Planetary Camera 2(WFPC-2) and the Corrective Optics Space Telescope Axial Replacement (COSTAR) were undergoing integrated testing prior to their installation in the Hubble Space Telescope on its first servicing mission. Areas for further investigation are presented.

  9. 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.

  10. Risk assessment of vegetables irrigated with arsenic-contaminated water.

    PubMed

    Bhatti, S M; Anderson, C W N; Stewart, R B; Robinson, B H

    2013-10-01

    Arsenic (As) contaminated water is used in South Asian countries to irrigate food crops, but the subsequent uptake of As by vegetables and associated human health risk is poorly understood. We used a pot trial to determine the As uptake of four vegetable species (carrot, radish, spinach and tomato) with As irrigation levels ranging from 50 to 1000 μg L(-1) and two irrigation techniques, non-flooded (70% field capacity for all studied vegetables), and flooded (110% field capacity initially followed by aerobic till next irrigation) for carrot and spinach only. Only the 1000 μg As L(-1) treatment showed a significant increase of As concentration in the vegetables over all other treatments (P < 0.05). The distribution of As in vegetable tissues was species dependent; As was mainly found in the roots of tomato and spinach, but accumulated in the leaves and skin of root crops. There was a higher concentration of As in the vegetables grown under flood irrigation relative to non-flood irrigation. The trend of As bioaccumulation was spinach > tomato > radish > carrot. The As concentration in spinach leaves exceeded the Chinese maximum permissible concentration for inorganic As (0.05 μg g(-1) fresh weight) by a factor of 1.6 to 6.4 times. No other vegetables recorded an As concentration that exceeded this threshold. The USEPA parameters hazard quotient and cancer risk were calculated for adults and adolescents. A hazard quotient value greater than 1 and a cancer risk value above the highest target value of 10(-4) confirms potential risk to humans from ingestion of spinach leaves. In our study, spinach presents a direct risk to human health where flood irrigated with water containing an arsenic concentration greater than 50 μg As L(-1). PMID:23934025

  11. Riverland ERA maintenance pad site diesel contamination risk assessment

    SciTech Connect

    Valcich, P.J.

    1993-12-02

    The maintenance pad site consists of a concrete pad and underlying soils, approximately 15 by 46 m in area, and a drainage ditch with dimensions of 2.4 by 91 m. The ditch is located approximately 60 m from the concrete pad and is oriented parallel to the pads long axis. The facility was built in 1943, at which time the concrete pad was the floor of a maintenance shed for railroad activities. In 1955, use of the facility as a maintenance shed was discontinued. Between 1955 and 1957, the facility was used as a radioactivity decontamination area for railroad cars; acetone-soaked rags were used to remove surface contamination from the cars. The concrete pad was washed down with a mixture of water and diesel fuel, which was then flushed via clay pipe to the drainage ditch. In 1963, the maintenance shed was torn down and the concrete pad covered with approximately one-half meter of fill. The concrete pad was re-exposed in 1993. The site was sampled for Toxicity Characteristic Leachate Procedure (TCLP) metals, volatile, and semi-volatile compounds, as well as for extractable fuel hydrocarbons. A total of 17 samples were collected from surface concrete, soil beneath surface concrete, and ditch soil. One concrete sample and one ditch soil sample were split. The ditch soil sample was also duplicated. The relative percent difference (RPD) in extractable hydrocarbons of the two split samples, one from concrete and one from ditch soil are, respectively, 52% and 186%. The RPD for the duplicate sample, taken from the same ditch soil sample from which one of the splits was taken, is 39%.

  12. 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). PMID:16849378

  13. Assessment of the contamination of marine fauna by chlordecone in Guadeloupe and Martinique (Lesser Antilles).

    PubMed

    Dromard, Charlotte R; Bodiguel, Xavier; Lemoine, Soazig; Bouchon-Navaro, Yolande; Reynal, Lionel; Thouard, Emmanuel; Bouchon, Claude

    2016-01-01

    Chlordecone is an organochlorine pesticide, used in the Lesser Antilles from 1972 to 1993 to fight against a banana weevil. That molecule is very persistent in the natural environment and ends up in the sea with runoff waters. From 2003 to 2013, seven campaigns of samplings have been conducted to evaluate the level of contamination of fish, crustaceans, and mollusks. The present study is the first assessment and the first comparison of the concentrations of chlordecone between marine areas, taxonomic groups, and ecological factors like trophic groups or preferential habitat of fish species. The four most contaminated marine areas are located downstream the contaminated rivers and banana plantations. Crustaceans seemed to be more sensitive to the contamination than fish or mollusks. Finally, when comparing contamination of fish according to their ecology, we found that fish usually living at the border of mangrove and presenting detritivores-omnivores diets were the most contaminated by chlordecone. These results are particularly useful to protect the health of the local population by controlling the fishing and the commercialization of seafood products, potentially contaminated by chlordecone. PMID:25994274

  14. Trace metals in the surface sediments of the intertidal Jiaozhou Bay, China: Sources and contamination assessment.

    PubMed

    Xu, Fangjian; Qiu, Longwei; Cao, Yingchang; Huang, Jingli; Liu, Zhaoqing; Tian, Xu; Li, Anchun; Yin, Xuebo

    2016-03-15

    The major (Al) and trace metal (Cu, Pb, Zn, Cr, Cd, and As) concentrations in 29 surface sediment samples from the intertidal Jiaozhou Bay (JZB) are evaluated to assess the contamination level. The results show that the overall sediment quality in the area has been obviously impacted by trace metal contamination. The geoaccumulation index and the enrichment factor values indicate that no Cr or Cu contamination has occurred on the whole, only a few stations have been polluted by As, and some areas have been polluted by Cd, Pb, and Zn. Principal component analysis suggests that the Cu, Pb, Zn, and Cd are derived from anthropogenic inputs and that Cr, As, Cu, and Zn are influenced by natural weathering processes. Cu and Zn may originate from both natural and anthropogenic sources. The contamination in the northeastern JZB is higher than that in other areas of the bay. PMID:26806660

  15. Assessment of diesel contamination in groundwater using electromagnetic induction geophysical techniques

    SciTech Connect

    Jin, S.; Fallgren, P.; Cooper, J.; Morris, J; . Urynowicz, M.

    2008-07-01

    Determining hydrocarbon plumes in groundwater is typically accomplished through the installation of extensive monitoring wells. Issues of scale and site heterogeneities tend to introduce errors in delineating the extent of contamination and environmental impact. In this study, electromagnetic induction survey was investigated as an alternative technique for mapping petroleum contaminants in the subsurface. The surveys were conducted at a coal mining site near Gillette, Wyoming, using the EM34-XL ground conductivity meter. Data from this survey were validated with known concentrations of diesel compounds detected in groundwater from the study site. Groundwater data correlated well with the electromagnetic survey data, which was used to generate a site model to identify subsurface diesel plumes. To our knowledge, this is one of the first studies to use electromagnetic survey techniques for mapping hydrocarbon contamination in groundwater. Results from this study indicate that this geophysical technique can be an effective tool for assessing subsurface petroleum hydrocarbon sources and plumes at contaminated sites.

  16. Assessing potential impacts associated with contamination events in water distribution systems : a sensitivity analysis.

    SciTech Connect

    Davis, M. J.; Janke, R.; Taxon, T. N.

    2010-11-01

    An understanding of the nature of the adverse effects that could be associated with contamination events in water distribution systems is necessary for carrying out vulnerability analyses and designing contamination warning systems. This study examines the adverse effects of contamination events using models for 12 actual water systems that serve populations ranging from about 104 to over 106 persons. The measure of adverse effects that we use is the number of people who are exposed to a contaminant above some dose level due to ingestion of contaminated tap water. For this study the number of such people defines the impact associated with an event. We consider a wide range of dose levels in order to accommodate a wide range of potential contaminants. For a particular contaminant, dose level can be related to a health effects level. For example, a dose level could correspond to the median lethal dose, i.e., the dose that would be fatal to 50% of the exposed population. Highly toxic contaminants may be associated with a particular response at a very low dose level, whereas contaminants with low toxicity may only be associated with the same response at a much higher dose level. This report focuses on the sensitivity of impacts to five factors that either define the nature of a contamination event or involve assumptions that are used in assessing exposure to the contaminant: (1) duration of contaminant injection, (2) time of contaminant injection, (3) quantity or mass of contaminant injected, (4) population distribution in the water distribution system, and (5) the ingestion pattern of the potentially exposed population. For each of these factors, the sensitivities of impacts to injection location and contaminant toxicity are also examined. For all the factors considered, sensitivity tends to increase with dose level (i.e., decreasing toxicity) of the contaminant, with considerable inter-network variability. With the exception of the population distribution (factor 4

  17. Bacterial diversity in a contaminated Alpine glacier as determined by culture-based and molecular approaches.

    PubMed

    Cappa, Fabrizio; Suciu, Nicoleta; Trevisan, Marco; Ferrari, Susanna; Puglisi, Edoardo; Cocconcelli, Pier Sandro

    2014-11-01

    Glaciers are important ecosystems, hosting bacterial communities that are adapted to cold conditions and scarcity of available nutrients. Several works focused on the composition of bacterial communities in glaciers and on the long-range atmospheric deposition of pollutants in glaciers, but it is not clear yet if ski resorts can represent a source of point pollution in near-by glaciers, and if these pollutants can influence the residing bacterial communities. To test these hypotheses, 12 samples were analyzed in Madaccio Glacier, in a 3200 ma.s.l. from two areas, one undisturbed and one close to a summer ski resort that is active since the 1930s. Chemical analyses found concentrations up to 43 ng L(-1) for PCBs and up to 168 μg L(-1) for PAHs in the contaminated area: these values are significantly higher than the ones found in undisturbed glaciers because of long-range atmospheric deposition events, and can be explained as being related to the near-by ski resort activities. Isolation of strains on rich medium plates and PCR-DGGE analyses followed by sequencing of bands allowed the identification of a bacterial community with phylogenetic patterns close to other glacier environments, with Proteobacteria and Actinobacteria the mostly abundant phyla, with Acidobacteria, Firmicutes and Cyanobacteria also represented in the culture-independent analyses. A number of isolates were identified by molecular and biochemical methods as phylogenetic related to known xenobiotic-degrading strains: glaciers subjected to chemical contamination can be important reservoirs of bacterial strains with potential applications in bioremediation. PMID:25117971

  18. Identification and Molecular Interaction Studies of Thyroid Hormone Receptor Disruptors among Household Dust Contaminants.

    PubMed

    Zhang, Jin; Li, Yaozong; Gupta, Arun A; Nam, Kwangho; Andersson, Patrik L

    2016-08-15

    Thyroid hormone disrupting chemicals (THDCs), often found abundantly in the environment, interfere with normal thyroid hormone signaling and induce physiological malfunctions, possibly by affecting thyroid hormone receptors (THRs). Indoor dust ingestion is a significant human exposure route of THDCs, raising serious concerns for human health. Here, we developed a virtual screening protocol based on an ensemble of X-ray crystallographic structures of human THRβ1 and the generalized Born solvation model to identify potential THDCs targeting the human THRβ1 isoform. The protocol was applied to virtually screen an in-house indoor dust contaminant inventory, yielding 31 dust contaminants as potential THRβ1 binders. Five predicted binders and one negative control were tested using isothermal titration calorimetry, of which four, i.e., 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), bisphenol A (3-chloro-2-hydroxypropyl) (2,3-dihydroxypropyl) ether (BADGE-HCl-H2O), 2,2',4,4'-tetrahydroxybenzophenone (BP2), and 2,4-dichlorophenoxyacetic acid (2,4-D), were identified as THRβ1 binders with binding affinities ranging between 60 μM and 460 μM. Molecular dynamics (MD) simulations were employed to examine potential binding modes of these binders and provided a rationale for explaining their specific recognition by THRβ1. The combination of in vitro binding affinity measurements and MD simulations allowed identification of four new potential THR-targeting THDCs that have been found in household dust. We suggest using the developed structure-based virtual screening protocol to identify and prioritize testing of potential THDCs. PMID:27410513

  19. Low pressure drop filtration of airborne molecular organic contaminants using open-channel networks

    NASA Astrophysics Data System (ADS)

    Dallas, Andrew J.; Joriman, Jon; Ding, Lefei; Weineck, Gerald; Seguin, Kevin

    2007-03-01

    Airborne molecular contamination (AMC) continues to play a very decisive role in the performance of many microelectronic devices and manufacturing processes. Besides airborne acids and bases, airborne organic contaminants such as 1-methyl-2-pyrrolidinone (NMP), hexamethyldisiloxane (HMDSO), trimethylsilanol (TMS), perfluoroalkylamines and condensables are of primary concern in these applications. Currently, the state of the filtration industry is such that optimum filter life and removal efficiency for organics is offered by granular carbon filter beds. However, the attributes that make packed beds of activated carbon extremely efficient also impart issues related to elevated filter weight and pressure drop. Most of the lower pressure drop AMC filters currently offered are quite expensive and are simply pleated combinations of various adsorptive and reactive media. On the other hand, low pressure drop filters, such as those designed as open-channel networks (OCN's), offer good filter life and removal efficiency with the additional benefits of significant reductions in overall filter weight and pressure drop. Equally important for many applications, the OCN filters can reconstruct the airflow so as to enhance the operation of a tool or process. For tool mount assemblies and fan filter units (FFUs) this can result in reduced fan and blower speeds, which subsequently can provide reduced vibration and energy costs. Additionally, these low pressure drop designs can provide a cost effective way of effectively removing AMC in full fab (or HVAC) filtration applications without significantly affecting air-handling requirements. Herein, we will present a new generation of low pressure drop OCN filters designed for the removal of airborne organics in a wide range of applications.

  20. 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.

  1. Janus microspheres for visual assessment of molecular interconnects.

    PubMed

    Fliedel, Christophe; Faramarzi, Vina; Rosa, Vitor; Doudin, Bernard; Braunstein, Pierre

    2014-01-27

    A rigid S-functionalized metalloligand is used to pair Janus Au-coated silica microspheres and the resulting assemblies are assessed with optical microscopy. New Pd complexes provide stable molecular interconnects, and the metal centre controls the structure of the linker and provides the desired rigidity, by virtue of its well-established coordination chemistry. PMID:24382696

  2. 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. PMID:22773148

  3. 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

  4. Assessing exposures and risks in heterogeneously contaminated areas: A simulation approach

    SciTech Connect

    Fingleton, D.J.; MacDonell, M.M.; Haroun, L.A. ); Oezkaynak, H.; Butler, D.A.; Jianping Xue )

    1991-01-01

    The US Department of Energy (DOE) is responsible for cleanup activities at a number of facilities under its Environmental Restoration and Waste Management Program. The major goals of this program are to eliminate potential hazards to human health and the environment that are associated with contamination of these sites and, to the extent possible, make surplus real property available for other uses. The assessment of potential baseline health risks and ecological impacts associated with a contaminated site is an important component of the remedial investigation/feasibility study (RI/FS) process required at all Superfund sites. The purpose of this paper is to describe one phase of the baseline assessment, i.e., the characterization of human health risks associated with exposure to chemical contaminants in air and on interior building surfaces at a contaminated site. The model combines data on human activity patterns in a particular microenvironment within a building with contaminant concentrations in that microenvironment to calculate personal exposure profiles and risks within the building. The results of the building assessment are presented as probability distributions functions and cumulative distribution functions, which show the variability and uncertainty in the risk estimates. 23 refs., 2 figs., 1 tab.

  5. Assessing nitrate contamination and its potential health risk to Kinmen residents.

    PubMed

    Liu, Chen-Wuing; Lin, Chun-Nan; Jang, Cheng-Shin; Ling, Min-Pei; Tsai, Jeng-Wei

    2011-10-01

    Kinmen is located in the southwest of Mainland China. Groundwater supplies 50% of the domestic water use on the island. Residents of Kinmen drink groundwater over the long term because surface water resources are limited. Nitrate-N pollution is found and distributed primarily in the western part of groundwater aquifer whereas saline groundwater is distributed to the northeastern Kinmen. This work applied the DRASTIC model to construct the vulnerability map of Kinmen groundwater. MT3D was then used to evaluate the contamination potential of nitrate-N. The health risk associated with the ingestion of nitrate-N contaminated groundwater is also assessed. The results from DRASTIC model showed that the upland crop and grass land have high contamination potential, whereas the forest, reservoir and housing land have low contamination potential. The calibrated MT3D model inversely determined the high strength sources (0.09-2.74 kg/m(2)/year) of nitrate contaminant located in the west to the north west area and required 2-5 years travel time to reach the monitoring wells. Simulated results of MT3D also showed that both the continuous and instantaneous contaminant sources of nitrate-N release may cause serious to moderate nitrate contamination in the western Kinmen and jeopardize the domestic use of groundwater. The chronic health hazard quotient (HQ) associated with the potential non-carcinogenic risk of drinking nitrate-N contaminated groundwater showed that the assessed 95th percentile of HQ is 2.74, indicating that exposure to waterborne nitrate poses a potential non-cancer risk to the residents of the island. Corrective measures, including protecting groundwater recharge zones and reducing the number of agricultural and non-agricultural nitrogen sources that enters the aquifer, should be implemented especially in the western part of Kinmen to assure a sustainable use of groundwater resources. PMID:21107656

  6. Assessment of contaminant fate in catchments using a novel integrated hydrobiogeochemical-multimedia fate model.

    PubMed

    Nizzetto, Luca; Butterfield, Dan; Futter, Martyn; Lin, Yan; Allan, Ian; Larssen, Thorjørn

    2016-02-15

    Models for pollution exposure assessment typically adopt an overly simplistic representation of geography, climate and biogeochemical processes. This strategy is unsatisfactory when high temporal resolution simulations for sub-regional spatial domains are performed, in which parameters defining scenarios can vary interdependently in space and time. This is, for example, the case when assessing the influence of biogeochemical processing on contaminant fate. Here we present INCA-Contaminants, the Integrated Catchments model for Contaminants; a new model that simultaneously and realistically solves mass balances of water, carbon, sediments and contaminants in the soil-stream-sediment system of catchments and their river networks as a function of climate, land use/management and contaminant properties. When forced with realistic climate and contaminant input data, the model was able to predict polychlorinated biphenyls (PCBs) concentrations in multiple segments of a river network in a complex landscape. We analyzed model output sensitivity to a number of hydro-biogeochemical parameters. The rate of soil organic matter mineralization was the most sensitive parameter controlling PCBs levels in river water, supporting the hypothesis that organic matter turnover rates will influence re-mobilization of previously deposited PCBs which had accumulated in soil organic matrix. The model was also used to project the long term fate of PCB 101 under two climate scenarios. Catchment diffuse run-off and riverine transport were the major pathways of contaminant re-mobilization. Simulations show that during the next decade the investigated boreal catchment will shift from being a net atmospheric PCB sink to a net source for air and water, with future climate perturbation having little influence on this trend. Our results highlight the importance of using credible hydro-biogeochemical simulations when modeling the fate of hydrophobic contaminants. PMID:26674684

  7. Multimedia contaminant environmental exposure assessment methodology as applied to Los Alamos, New Mexico

    SciTech Connect

    Whelan, G.; Thompson, F.L.; Yabusaki, S.B.

    1983-02-01

    The MCEA (Multimedia Contaminant Environmental Exposure Assessment) methodology assesses exposures to air, water, soil, and plants from contaminants released into the environment by simulating dominant mechanisms of contaminant migration and fate. The methodology encompasses five different pathways (i.e., atmospheric, terrestrial, overland, subsurface, and surface water) and combines them into a highly flexible tool. The flexibility of the MCEA methodology is demonstrated by encompassing two of the pathways (i.e., overland and surface water) into an effective tool for simulating the migration and fate of radionuclides released into the Los Alamos, New Mexico region. The study revealed that: (a) the /sup 239/Pu inventory in lower Los Alamos Canyon increased by approximately 1.1 times for the 50-y flood event; (b) the average contaminant /sup 239/Pu concentrations (i.e., weighted according to the depth of the respective bed layer) in lower Los Alamos Canyon for the 50-y flood event decreased by 5.4%; (c) approx. 27% of the total /sup 239/Pu contamination resuspended from the entire bed (based on the assumed cross sections) for the 50-y flood event originated from lower Pueblo Canyon; (d) an increase in the /sup 239/Pu contamination of the bed followed the general deposition patterns experienced by the sediment in Pueblo-lower Los Alamos Canyon; likewise, a decrease in the /sup 239/Pu contamination of the bed followed general sediment resuspension patterns in the canyon; (e) 55% of the /sup 239/Pu reaching the San Ildefonso Pueblo in lower Los Alamos Canyon originated from lower Los Alamos Canyon; and (f) 56% of the /sup 239/Pu contamination reaching the San Ildefonso Pueblo in lower Los Alamos Canyon was carried through towards the Rio Grande. 47 references, 41 figures, 29 tables.

  8. Levels and risk assessment of chemical contaminants in byproducts for animal feed in Denmark.

    PubMed

    Mortensen, Alicja; Granby, Kit; Eriksen, Folmer D; Cederberg, Tommy Licht; Friis-Wandall, Søren; Simonsen, Yvonne; Broesbøl-Jensen, Birgitte; Bonnichsen, Rikke

    2014-01-01

    With aim to provide information on chemical contaminants in byproducts in animal feed, the data from an official control by the Danish Plant Directorate during 1998-2009, were reviewed and several samples of citrus pulp and dried distillers grains with solubles (DDGS) were additionally collected for analysis and risk assessment. The levels of contaminants in the samples from the official control were below maximum limits from EU regulations with only a few exceptions in the following groups; dioxins and dioxin-like polychlorobiphenyls (PCBs) in fish-containing byproducts and dioxins in vegetable and animal fat, hydrogen cyanide in linseed, and cadmium in sunflowers. The levels of pesticides and mycotoxins in the additionally collected samples were below maximum limits. Enniatin B (ENN B) was present in all DDGS samples. The hypothetical cases of carry-over of contamination from these byproducts were designed assuming total absorption and accumulation of the ingested contaminant in meat and milk and high exposure (a byproduct formed 15-20% of the feed ration depending on the species). The risk assessment was refined based on literature data on metabolism in relevant animal species. Risk assessment of contaminants in byproducts is generally based on a worst-case approach, as data on carry-over of a contaminant are sparse. This may lead to erroneous estimation of health hazards. The presence of ENN B in all samples of DDGS indicates that potential impact of this emerging mycotoxin on feed and food safety deserves attention. A challenge for the future is to fill up gaps in toxicological databases and improve models for carry-over of contaminants. PMID:25190554

  9. 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

  10. Waste Area Grouping 2 Remedial Investigation Phase 1 Seep Task data report: Contaminant source area assessment

    SciTech Connect

    Hicks, D.S.

    1996-03-01

    This report presents the findings of the Waste Area Grouping (WAG) 2, Phase 1 Remedial Investigation (RI) Seep Task efforts during 1993 and 1994 at Oak Ridge National Laboratory (ORNL). The results presented here follow results form the first year of sampling, 1992, which are contained in the Phase 1 RI report for WAG 2 (DOE 1995a). The WAG 2 Seep Task efforts focused on contaminants in seeps, tributaries, and main streams within the White Oak Creek (WOC) watershed. This report is designed primarily as a reference for contaminants and a resource for guiding remedial decisions. Additional in-depth assessments of the Seep Task data may provide clearer understandings of contaminant transport from the different source areas in the WOC watershed. WAG 2 consists of WOC and its tributaries downstream of the ORNL main plant area, White Oak Lake, the White Oak Creek Embayment of the Clinch River, and the associated flood plains and subsurface environment. The WOC watershed encompasses ORNL and associated WAGs. WAG 2 acts as an integrator for contaminant releases from the contaminated sites at ORNL and as the conduit transporting contaminants to the Clinch River. The main objectives of the Seep Task were to identify and characterize seeps, tributaries and source areas that are responsible for the contaminant releases to the main streams in WAG 2 and to quantify their input to the total contaminant release from the watershed at White Oak Dam (WOD). Efforts focused on {sup 90}Sr, {sup 3}H, and {sup 137}Cs because these contaminants pose the greatest potential human health risk from water ingestion at WOD. Bimonthly sampling was conducted throughout the WOC watershed beginning in March 1993 and ending in August 1994. Samples were also collected for metals, anions, alkalinity, organics, and other radionuclides.

  11. Molecular conductance of a contact-free labyrinth seal used for the contamination control of a cryogenic space instrument

    NASA Astrophysics Data System (ADS)

    Glauser, Adrian M.; Langer, Ulrich; Zehnder, Alex

    2009-01-01

    This study presents the molecular conductance measurement of a labyrinth seal introduced for the Contamination Control Cover which is protecting the cryogenic optical surfaces of the mid-infrared instrument of the James Webb Space Telescope against molecular contaminants from the environment. The conductance has been measured in the molecular pressure regime between 10-7 and 10-3 mbar within a temperature range of 300 K and 10 K for several typical components of the expected residual gas such as H2O, NH3, CO2, H2, NO, alcohols and hydrocarbons as well as standard gases such as N2 and He. The measurements have been repeated with a thin orifice to verify the systematics. The results are well consistent with numerically derived values and demonstrate a robust understanding of the design and performance of the labyrinth seal.

  12. 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. PMID:26765509

  13. 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. PMID:27484140

  14. Multispecies toxicity assessment of compost produced in bioremediation of an explosives-contaminated sediment

    SciTech Connect

    Gunderson, C.A.; Napolitano, G.E.; Wicker, L.F.; Richmond, J.E.; Stewart, A.J.; Kostuk, J.M.; Gibbs, M.H.

    1997-12-01

    A multispecies terrestrial test system was used to assess the environmental effectiveness of composting for bioremediation of explosives-contaminated soils. The assessment involved comparing biological responses, from the individual to the community level, in remediated and reference composts. A 6-month greenhouse study incorporated two soil invertebrate species, three plant species and an associated symbiont, and the naturally occurring complement of soil microorganisms. Measured parameters included growth and reproduction of earthworms and isopods; soil mote diversity; soil lipid class composition as an indicator of soil microbial community structure; plant growth, photosynthesis, and reproduction; and root nodulation and symbiotic N{sub 2} fixation. Additional short-term toxicity tests of seed germination and earthworm survival were performed to supplement the mesocosm data. Compost prepared from the explosives-contaminated soil inhibited several aspects of plant growth and physiology, but few adverse effects on soil invertebrates were detected. An initial lag in earthworm and isopod reproduction occurred in the reference compost, reflecting some inherent compost differences not associated with contamination, and highlighting the importance and the difficulty of finding appropriate reference soils for assessing hazardous waste sites or remediation technologies. Nonetheless, the results from this study suggested some nonlethal effects from the contaminated-soil compost, primarily to plants. The mesocosm methodology used in this study can bridge the gap between traditional short-term toxicity testing and longer term field assessments, and provide information on ecological effects by explicitly including measurements of multiple species across several levels of ecological organization.

  15. A dynamic multimedia fuzzy-stochastic integrated environmental risk assessment approach for contaminated sites management.

    PubMed

    Hu, Yan; Wen, Jing-Ya; Li, Xiao-Li; Wang, Da-Zhou; Li, Yu

    2013-10-15

    A dynamic multimedia fuzzy-stochastic integrated environmental risk assessment approach was developed for contaminated sites management. The contaminant concentrations were simulated by a validated interval dynamic multimedia fugacity model, and different guideline values for the same contaminant were represented as a fuzzy environmental guideline. Then, the probability of violating environmental guideline (Pv) can be determined by comparison between the modeled concentrations and the fuzzy environmental guideline, and the constructed relationship between the Pvs and environmental risk levels was used to assess the environmental risk level. The developed approach was applied to assess the integrated environmental risk at a case study site in China, simulated from 1985 to 2020. Four scenarios were analyzed, including "residential land" and "industrial land" environmental guidelines under "strict" and "loose" strictness. It was found that PAH concentrations will increase steadily over time, with soil found to be the dominant sink. Source emission in soil was the leading input and atmospheric sedimentation was the dominant transfer process. The integrated environmental risks primarily resulted from petroleum spills and coke ovens, while the soil environmental risks came from coal combustion. The developed approach offers an effective tool for quantifying variability and uncertainty in the dynamic multimedia integrated environmental risk assessment and the contaminated site management. PMID:23995555

  16. 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 research…

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  1. Macroporous molecularly imprinted polymer/cryogel composite systems for the removal of endocrine disrupting trace contaminants.

    PubMed

    Le Noir, Mathieu; Plieva, Fatima; Hey, Tobias; Guieysse, Benoit; Mattiasson, Bo

    2007-06-22

    A new concept for the preparation of selective sorbents with high flow path properties is presented by embedding molecularly imprinted polymers (MIPs) into various macroporous gels (MGs). A MIP was first synthetized with 17beta-estradiol (E2) as template for the selective adsorption of this endocrine disrupter. The composite macroporous gel/MIP (MG/MIP) monoliths were then prepared at subzero temperatures. Complete recovery of E2 from a 2 microg/L aqueous solution was achieved using the polyvinyl alcohol (PVA) MG/MIP monoliths whereas only 49-74% was removed with non-imprinted polymers (when no template was used). The PVA MG/MIP monolith columns were operated at almost 10 times higher flow rate (50 mL/min) compared to the MIP columns with operation flow rate of 1-5 mL/min. The possibility for processing the particulate containing wastewater effluents at high flow rates with selectivity on E2 removal, as well as the easy preparation of the monoliths, make the macroporous MG/MIP systems attractive and robust sorbents for the clean up of water from endocrine disrupting trace contaminants. PMID:17449053

  2. Molecular characterization and lipase profiling of the yeasts isolated from environments contaminated with petroleum.

    PubMed

    Yalçın, H Tansel; Corbacı, Cengiz; Uçar, Füsun B

    2014-07-01

    In the present study, 120 yeast isolates from different sources (active sludge, soil, and wastewater samples obtained from petroleum refinery and soil contaminated by petroleum) were obtained. The yeast isolates were screened for lipase production and twelve of the isolates (D3, D17, D24, D27, D30, D38, D40, D42, D44, D46, D56, and D57) exhibited lipase activity. Molecular characterization of the yeasts showing the lipase production was performed with RFLP of ITS1-5.8S-ITS2 and 18S rRNA and sequence analysis of D1/D2 domain of 26S rRNA. The 26S rRNA sequencing revealed that four new strains, D38, D40, D44 and D57 identified as Rhodotorula slooffiae, Candida davisiana, Cryptococcus diffluens, and Cryptococcus uzbekistanensis, respectively, are lipase producing yeast species. This study is the first report showed lipase production by these species. The other lipase producing strains identified as Candida parapsilosis (D3), Rhodotorula muciloginosa (D17 and D42), Cryptococcus albidus (D24, D27, D30, and D56), and Wickerhamomyces anomalus (D46). PMID:23712936

  3. Baseline risk assessment of ground water contamination at the Uranium Mill Tailings Site at Grand Junction, Colorado. Revision 1

    SciTech Connect

    Not Available

    1994-09-01

    This risk assessment evaluates potential impacts to public health or the environment resulting from ground water contamination at the former uranium mill processing site. The tailings and other contaminated material at this site were placed in an off-site disposal cell by the US Department of Energy`s (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project. The remedial activities at the site were conducted from 1989 to 1993. Currently, the UMTRA Project is evaluating ground water contamination. This risk assessment evaluates the most contaminated ground water that flows beneath the processing site toward the Colorado River. The monitor wells that have consistently shown the highest concentrations of most contaminants are used to assess risk. This risk assessment will be used in conjunction with additional activities and documents to determine what remedial action may be needed for contaminated ground water at the site.

  4. Beyond contaminated land assessment: on costs and benefits of bioaccessibility prediction.

    PubMed

    Latawiec, Agnieszka E; Reid, Brian J

    2009-08-01

    Advances towards sustainable land management necessitate application of a broader portfolio of decision-support tools that improve evaluation of contaminated land. Over the last decade regulators have directed concerted effort towards rationalization of risk-based contaminated land policies recognizing bioavailability and bioaccessibility as concepts to be incorporated into risk assessments. The desire for a precise and rapid method to inform consideration of bioavailability and bioaccessibility to support risk assessment of contaminated land has never been greater. This study presents a comprehensive appraisal of both emerging non-exhaustive extraction techniques (subcritical water extraction and Brij 700 extraction) developed to reflect polycyclic aromatic hydrocarbon (PAH) bioaccessibility to microorganisms as well as formerly demonstrated methodologies (the use of cyclodextrins and butanol extraction). Application of unified evaluation criteria across different techniques enabled comparison not only from the bioaccessibility prediction perspective but also analysis of economical (cost of extraction) and practical (such as extraction time) measures. Whilst the use of cyclodextrins was the best predictor of the bioaccessible fraction for the majority of compounds, other methods appeared more cost- and time-effective. Juxtaposition of the techniques presented in this study assists establishing cost-benefit trade-offs of different non-exhaustive extraction techniques and contributes to tailoring information on contaminant bioaccessibility to support risk evaluation on contaminated sites. PMID:19403173

  5. 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. PMID:21520943

  6. 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.

  7. Assessment of radionuclide and metal contamination in a thorium rich area in Norway.

    PubMed

    Popic, Jelena Mrdakovic; Salbu, Brit; Strand, Terje; Skipperud, Lindis

    2011-06-01

    The Fen Central Complex in southern Norway, a geologically well investigated area of magmatic carbonatite rocks, is assumed to be among the world largest natural reservoirs of thorium ((232)Th). These rocks, also rich in iron (Fe), niobium (Nb), uranium ((238)U) and rare earth elements (REE), were mined in several past centuries. Waste locations, giving rise to enhanced levels of both radionuclides and metals, are now situated in the area. Estimation of radionuclide and metal contamination of the environment and radiological risk assessment were done in this study. The average outdoor gamma dose rate measured in Fen, 2.71 μGy h(-1), was significantly higher than the world average dose rate of 0.059 μGy h(-1). The annual exposure dose from terrestrial gamma radiation, related to outdoor occupancy, was in the range 0.18-9.82 mSv. The total activity concentrations of (232)Th and (238)U in soil ranged from 69 to 6581 and from 49 to 130 Bq kg(-1), respectively. Enhanced concentrations were also identified for metals, arsenic (As), lead (Pb), chromium (Cr) and zinc (Zn), in the vicinity of former mining sites. Both radionuclide and heavy metal concentrations suggested leaching, mobilization and distribution from rocks into the soil. Correlation analysis indicated different origins for (232)Th and (238)U, but same or similar for (232)Th and metals As, Cr, Zn, nickel (Ni) and cadmium (Cd). The results from in situ size fractionation of water demonstrated radionuclides predominately present as colloids and low molecular mass (LMM) species, being potentially mobile and available for uptake in aquatic organisms of Norsjø Lake. Transfer factors, calculated for different plant species, showed the highest radionuclide accumulation in mosses and lichens. Uptake in trees was, as expected, lower. Relationship analysis of (232)Th and (238)U concentrations in moss and soil samples showed a significant positive linear correlation. PMID:21556423

  8. CONSIDERATIONS FOR DEVELOPING A DOSIMETRY-BASED CUMULATIVE RISK ASSESSMENT APPROACH FOR MIXTURES OF ENVIRONMENTAL CONTAMINANTS (Final Report)

    EPA Science Inventory

    This final report, Considerations for Developing a Dosimetry-Based Cumulative Risk Assessment Approach for Mixtures of Environmental Contaminants, addresses the justification for developing physiologically based pharmacokinetic (PBPK) models for cumulative risk assessment....

  9. International Mussel Watch: A global assessment of environmental levels of chemical contaminants

    SciTech Connect

    Not Available

    1992-01-01

    The primary goal of the International Mussel Watch is to ascertain and assess the levels of chlorinated hydrocarbon pesticide (CHP) and polychlorinated biphenyls (PCB) in bivalves collected from coastal marine waters throughout the world. Increased use of these persistent toxic biocides may result in contamination of living coastal resources from whole ecosystems to specific food resources with consequent implication for human health and the integrity of marine communities. Another goal for the International Mussel Watch Project will be to help develop a sustainable activity for observation and monitoring chemical contamination in especially susceptible regions of the world's oceans.

  10. 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.

    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

  11. National guidance for assessing the risks of consuming chemically contaminated fish

    SciTech Connect

    Bigler, J.

    1994-12-31

    The EPA`s Fish Contamination Program (FCP) provides technical assistance and guidance to State, Federal, and Tribal agencies for assessing human health risks associated with dietary exposure to chemically contaminated noncommercial freshwater and estuarine fish and shellfish. the program includes guidance documents which may be used for developing fish consumption advisories. One series of guidance documents, titled Guidance for Assessing Chemical Contaminant Data for Use in Fish Advisories, are designed to provide the States, Tribes, and other interested parties with a scientifically defensible, cost effective methodology for developing, implementing, managing and communicating risk-base fish consumption advisories. The fist document of the series, Volume 1: Fish Sampling and Analysis (September 1993), provides recommended methods for sampling strategies, field collection procedure, chemical analysis, data management and profiles of 24 chemicals which have been identified as analyses of concern with respect to dietary exposure to chemical contaminants in fish. volume 2: Risk Assessment and Fish Consumption Limits (June 1994), provides chemical specific risk based fish consumption limits for 24 analyses based on the amount and frequency of individual fish consumption patterns. Specific fish consumption limits and advice for the general population and women of child-bearing age are provided. Volume 3: Risk Management, is scheduled for release in late 1 994. This document will review management options which should be considered in the development of fish consumption advisories. Volume 4: Risk Communication, is scheduled for release in the fall of 1994. This document will address effective communication of fish consumption advisories to targeted audiences.

  12. Developing methods to assess and predict the population level effects of environmental contaminants.

    USGS Publications Warehouse

    Emlen, J.M.; Springman, K.R.

    2007-01-01

    The field of ecological toxicity seems largely to have drifted away from what its title implies--assessing and predicting the ecological consequences of environmental contaminants--moving instead toward an emphasis on individual effects and physiologic case studies. This paper elucidates how a relatively new ecological methodology, interaction assessment (INTASS), could be useful in addressing the field's initial goals. Specifically, INTASS is a model platform and methodology, applicable across a broad array of taxa and habitat types, that can be used to construct population dynamics models from field data. Information on environmental contaminants and multiple stressors can be incorporated into these models in a form that bypasses the problems inherent in assessing uptake, chemical interactions in the environment, and synergistic effects in the organism. INTASS can, therefore, be used to evaluate the effects of contaminants and other stressors at the population level and to predict how changes in stressor levels or composition of contaminant mixtures, as well as various mitigation measures, might affect population dynamics.

  13. Bioremediation of contaminated harbor sediment: Development of a treatment assessment strategy

    SciTech Connect

    De Brabandere, J.; De Pauw, N.; Janssen, C.R.; Dumon, G.; Vanderhaegen, B.

    1995-12-31

    Different ex-situ microbial remediation techniques were assessed for the clean-up of contaminated sediments in the harbor of Zeebrugge (Belgium). Sediment contamination typically consisted of PAHs (5 to 1,200 ppm), TBT (up to 400 ppb) and mineral oils (400 to 8,000 ppm). In a first bench-scale phase, the remediation-efficiency of techniques based on stimulation of indigenous bacteria, a and/or 3 commercially available strains was evaluated using a combination of kinetic, {sup 14}C and respiration experiments, aimed at determining the degradation pathways and overall fate of the contaminants. At a pilot-scale 3 selected remediation techniques were assessed in four 40 M{sup 3}batch reactors (second phase). Aquatic toxicity tests were used to monitor bioremediation efficiency and the potential hazard of wastes and remediation by-products. The results from both phases of this study indicate that selected ex-situ microbial remediation techniques of contaminated sediments can remove 90% of both mineral oils and TBT, and between 70 to 90% of the total PAH concentration. Microbial, chemical and ecotoxicological aspects of this study will be discussed and details about the application of the developed assessment strategy in a full-scale treatment plant will be given.

  14. Efficacy of a Passive Diffusion Sampler to Assess Microbial Spatial Dynamics in a Contaminated Aquifer-wetland System

    NASA Astrophysics Data System (ADS)

    Kirshtein, J. D.; Kneeshaw, T. A.; Voytek, M. A.; Cozzarelli, I. M.; McGuire, J. T.; Baez Cazull, S.

    2006-05-01

    Microbiological processes affect biogeochemical cycling of nutrients and contaminants in subsurface systems. Microbial response to changes in terminal electron accepting processes (TEAPs), and in turn the microbes' effect on TEAP distribution are critical to understanding the fate and transport of contaminants. A challenge to studying microbial processes is obtaining samples that yield enough biomass to assess microbial communities and are spatially and temporally representative of changes in water chemistry. Our study focuses on the interface between ground water affected by landfill leachate at the closed Norman, Oklahoma landfill and porewater in a slough adjacent to the landfill (a contaminated aquifer-wetland system). We used a combination of more traditional and newer molecular microbiological approaches to provide an extension of the biochemical and culture approaches commonly employed in studies of microbial processes in subsurface environments. In order to enable contemporaneous and spatially concordant sampling of water chemistry and microbiology, passive diffusion samplers containing sponge material at discrete intervals were installed in the slough sediment. Unlike peeper diffusion samplers, the sampler installed is porous enough to allow native organisms to flow through the device and colonize the substrate. In addition to obtaining critical biomass, this setup allows us to extract nucleic acids easily while minimizing the affect of inhibitors to molecular analyses that are found commonly in organic rich sediments and contaminated systems. Discrete interval microbe samplers (DIMPS, Geosyntec) were deployed at 2 sites in the Norman Landfill slough and allowed to equilibrate for 14 days before retrieval and removal of sponge substrate at 14 depth intervals. Cores were taken near the passive diffusion samplers, sectioned for Most Probable Number (MPN) analysis and assessed by quantitative PCR (qPCR) for microbial abundance of metabolically important

  15. Risk assessment of urban soils contamination: The particular case of polycyclic aromatic hydrocarbons.

    PubMed

    Cachada, A; da Silva, E Ferreira; Duarte, A C; Pereira, R

    2016-05-01

    The assessment of soil quality and characterization of potential risks to the environment and human health can be a very difficult task due to the heterogeneity and complexity of the matrix, the poor understanding about the fate of contaminants in the soil matrix, scarcity of toxicological/ecotoxicological data and variability of guidelines. In urban soils these difficulties are enhanced by the patchy nature of urban areas and the presence of complex mixtures of organic and inorganic contaminants resulting from diffuse pollution caused by urban activities (e.g. traffic, industrial activity, and burning of carbon sources for heating). Yet, several tools are available which may help to assess the risks of soil contamination in a simpler, cost effective and reliable way. Within these tools, a tiered risk assessment (RA) approach, first based on a chemical screening in combination with geostatistical tools, may be very useful in urban areas. However, there is still much to improve and a long way to go in order to obtain a reliable RA, especially in the case of hydrophobic organic compounds such as polycyclic aromatic hydrocarbons (PAHs). This paper aims at proposing a RA framework to assess the environmental and human health risks of PAHs present in urban soils, based on existing models. In addition, a review on ecotoxicological, toxicological, and exposure assessment data was made, as well as of the existing soil quality guidelines for PAHs that can be used in the RA process. PMID:26878639

  16. 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. PMID:25723126

  17. Assessment of metal contamination in coastal sediments, seawaters and bivalves of the Mediterranean Sea coast, Egypt.

    PubMed

    El-Sorogy, Abdelbaset S; Attiah, Abdullah

    2015-12-30

    In order to assess metal contamination on the Mediterranean coast of Egypt, 45 sediment samples, seawaters and bivalve specimens were collected from Rosetta coastal area for Mg, Al, K, Fe, Sr, Zn, Pb, Mn, As, Ce, Ni, Cr and Zr analyses by Inductively Coupled Plasma-Mass Spectrometer. The Enrichment Factor (EF), the Geoaccumulation Index (Igeo) and the Contamination Factor (CF) indicated that the coastal sediments of Rosetta area were severely enriched, strongly polluted with As, Pb and very highly contaminated with As, Pb, Ni, Ce, mostly as a result of anthropogenic inputs. Comparison with other samples from the Arabian Gulf, Red Sea and abroad coasts suggested that the studied samples have higher concentrations of Fe, Pb, As, Zn and Ni. The natural sources of heavy metals in the study area are attributed to weathering and decomposition of mountain ranges of the Sudan and Ethiopia, while the anthropogenic ones are the metals produced from industrial, sewage, irrigation and urban runoff. PMID:26563548

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

    SciTech Connect

    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 tests 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.

  19. Baseline risk assessment of ground water contamination at the Uranium Mill Tailings Site near Naturita, Colorado

    SciTech Connect

    1995-08-01

    The Uranium Mill Tailings Remedial Action (UMTRA) Project consists of the Surface Project (phase I), and the Ground Water Project (phase II). For the UMTRA Project site located near Naturita, Colorado (the Naturita site), phase I involves the removal of radioactively contaminated soils and materials and their transportation to a disposal site at Union Carbide Corporation`s Upper Burbank Repository at Uravan, Colorado, about 13 road miles (mi) (21 kilometers [km]) to the northwest. No uranium mill tailings are involved because the tailings were removed from the Naturita site and placed at Coke Oven, Colorado, during 1977 to 1979. Phase II of the project will evaluate the nature and extent of ground water contamination resulting from uranium processing and its effect on human health or the environment; and will determine site-specific ground water compliance strategies in accordance with the US Environmental Protection Agency (EPA) ground water standards established for the UMTRA Project. Human health risks could occur from drinking water pumped from a hypothetical well drilled in the contaminated ground water area. Environmental risks may result if plants or animals are exposed to contaminated ground water, or surface water that has received contaminated ground water. Therefore, a risk assessment is conducted for the Naturita site. This risk assessment report is the first site-specific document prepared for the Ground Water Project at the Naturita site. What follows is an evaluation of current and possible future impacts to the public and the environment from exposure to contaminated ground water. The results of this evaluation and further site characterization will be used to determine whether any action is needed to protect human health or the environment.

  20. 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

  1. Assessing the fate of biodegradable volatile organic contaminants in unsaturated soil filter systems

    NASA Astrophysics Data System (ADS)

    Thullner, Martin; de Biase, Cecilia; Hanzel, Joanna; Reger, Daniel; Wick, Lukas; Oswald, Sascha; van Afferden, Manfred; Schmidt, Axel; Reiche, Nils; Jechalke, Sven

    2010-05-01

    The assessment of contaminant biodegradation in the subsurface is challenged by various abiotic processes leading to a reduction of contaminant concentration without a destructive mass removal of the contaminant. In unsaturated porous media, this interplay of processes is further complicated by volatilization. Many organic contaminants are sufficiently volatile to allow for significant fluxes from the water phase into the soil air, which can eventually lead to an emission of contaminants into the atmosphere. Knowledge of the magnitude of these emissions is thus required to evaluate the efficiency of bioremediation in such porous media and to estimate potential risks due to these emissions. In the present study, vertical flow constructed wetlands were investigated at the pilot scale as part of the SAFIRA II project. The investigated wetland system is intermittently irrigated by contaminated groundwater containing the volatile compounds benzene and MTBE. Measured concentration at the in- and outflow of the system demonstrate a high mass removal rate, but the highly transient flow and transport processes in the system challenge the quantification of biodegradation and volatilization and their contribution to the observed mass removal. By a combination of conservative solute tracer tests, stable isotope fractionation and measurements of natural radon concentration is the treated groundwater is was possible to determine the contribution of biodegradation and volatilization to total mass removal. The results suggest that for the investigated volatile compounds biodegradation is the dominating mass removal process with volatilization contributing only to minor or negligible amounts. These results can be confirmed by reactive transport simulations and were further supported by laboratory studies showing that also gas phase gradients of volatile compounds can be affected by biodegradation suggesting the unsaturated zone to act as a biofilter for contaminants in the soil air.

  2. Baseline risk assessment of ground water contamination at the inactive uriniferous lignite ashing site near Belfield, North Dakota

    SciTech Connect

    1994-08-01

    This Baseline Risk Assessment of Ground Water Contamination at the Inactive Uraniferous Lignite Ashing Site Near Belfield, North Dakota, evaluates potential impacts to public health or the environment resulting from ground water contamination at the site where coal containing uranium was burned to produce uranium. The US Department of Energy`s Uranium Mill Tailings Remedial Action (UMTRA) Project is evaluating plans to remedy soil and ground water contamination at the site. Phase I of the UMTRA Project consists of determining the extent of soil contamination. Phase II of the UMTRA Project consists of evaluating ground water contamination. Under Phase II, results of this risk assessment will help determine what remedial actions may be necessary for contaminated ground water at the site. This risk assessment evaluates the potential risks to human health and the environment resulting from exposure to contaminated ground water as it relates to historic processing activities at the site. Potential risk is quantified for constituents introduced from the processing activities, and not for those constituents naturally occurring in water quality in the site vicinity. Background ground water quality has the potential to cause adverse health effects from exposure through drinking. Any risks associated with contaminants attributable to site activities are incremental to these risks from background ground water quality. This incremental risk from site-related contaminants is quantified in this risk assessment. The baseline risk from background water quality is incorporated only into the assessment of potential chemical interactions and the definition of the overall site condition.

  3. A Contamination Vulnerability Assessment for the Santa Clara and San Mateo County Groundwater Basins

    SciTech Connect

    Moran, J E; Hudson, G B; Eaton, G F; Leif, R

    2004-01-06

    In response to concerns expressed by the California Legislature and the citizenry of the State of California, the State Water Resources Control Board (SWRCB), implemented a program to assess groundwater quality, and provide a predictive capability for identifying areas that are vulnerable to contamination. The program was initiated in response to concern over public supply well closures due to contamination by chemicals such as MtBE from gasoline, and solvents from industrial operations. As a result of this increased awareness regarding groundwater quality, the Supplemental Report of the 1999 Budget Act mandated the SWRCB to develop a comprehensive ambient groundwater-monitoring plan, and led to the initiation of the Ambient Groundwater Monitoring and Assessment (GAMA) Program. The primary objective of the GAMA Program is to assess the water quality and to predict the relative susceptibility to contamination of groundwater resources throughout the state of California. Under the GAMA program, scientists from Lawrence Livermore National Laboratory (LLNL) collaborate with the SWRCB, the U.S. Geological Survey, the California Department of Health Services (DHS), and the California Department of Water Resources (DWR) to implement this groundwater assessment program. In 2001 and 2002, LLNL carried out this vulnerability study in the groundwater basins of Santa Clara County and San Mateo County, located to the south of the city of San Francisco. The goal of the study is to provide a probabilistic assessment of the relative vulnerability of groundwater used for the public water supply to contamination from surface sources. This assessment of relative contamination vulnerability is made based on the results of two types of analyses that are not routinely carried out at public water supply wells: ultra low-level measurement of volatile organic compounds (VOCs), and groundwater age dating (using the tritium-helium-3 method). In addition, stable oxygen isotope measurements

  4. California GAMA Program: A Contamination Vulnerability Assessment for the Bakersfield Area

    SciTech Connect

    Moran, J E; Hudson, G B; Eaton, G F; Leif, R

    2004-11-01

    In response to concerns expressed by the California Legislature and the citizenry of the State of California, the State Water Resources Control Board (SWRCB), implemented a program to assess groundwater quality, and provide a predictive capability for identifying areas that are vulnerable to contamination. The program was initiated in response to concern over public supply well closures due to contamination by chemicals such as MTBE from gasoline, and solvents from industrial operations. As a result of this increased awareness regarding groundwater quality, the Supplemental Report of the 1999 Budget Act mandated the SWRCB to develop a comprehensive ambient groundwater-monitoring plan, and led to the initiation of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The primary objective of the GAMA Program is to assess the water quality and to predict the relative susceptibility to contamination of groundwater resources throughout the state of California. Under the GAMA program, scientists from Lawrence Livermore National Laboratory (LLNL) collaborate with the SWRCB, the U.S. Geological Survey (USGS), the California Department of Health Services (DHS), and the California Department of Water Resources (DWR) to implement this groundwater assessment program. In 2003, LLNL carried out this vulnerability study in the groundwater basin that underlies Bakersfield, in the southern San Joaquin Valley. The goal of the study is to provide a probabilistic assessment of the relative vulnerability of groundwater used for the public water supply to contamination from surface sources. This assessment of relative contamination vulnerability is made based on the results of two types of analyses that are not routinely carried out at public water supply wells: ultra low-level measurement of volatile organic compounds (VOCs), and groundwater age dating (using the tritium-helium-3 method). In addition, stable oxygen isotope measurements help determine the recharge water

  5. 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. PMID:25813138

  6. Assessing microbial activities in metal contaminated agricultural volcanic soils - An integrative approach.

    PubMed

    Parelho, C; Rodrigues, A S; Barreto, M C; Ferreira, N G C; Garcia, P

    2016-07-01

    Volcanic soils are unique naturally fertile resources, extensively used for agricultural purposes and with particular physicochemical properties that may result in accumulation of toxic substances, such as trace metals. Trace metal contaminated soils have significant effects on soil microbial activities and hence on soil quality. The aim of this study is to determine the soil microbial responses to metal contamination in volcanic soils under different agricultural land use practices (conventional, traditional and organic), based on a three-tier approach: Tier 1 - assess soil microbial activities, Tier 2 - link the microbial activity to soil trace metal contamination and, Tier 3 - integrate the microbial activity in an effect-based soil index (Integrative Biological Response) to score soil health status in metal contaminated agricultural soils. Our results showed that microbial biomass C levels and soil enzymes activities were decreased in all agricultural soils. Dehydrogenase and β-glucosidase activities, soil basal respiration and microbial biomass C were the most sensitive responses to trace metal soil contamination. The Integrative Biological Response value indicated that soil health was ranked as: organic>traditional>conventional, highlighting the importance of integrative biomarker-based strategies for the development of the trace metal "footprint" in Andosols. PMID:27057992

  7. Children's exposure to mercury-contaminated soils: exposure assessment and risk characterization.

    PubMed

    Guney, Mert; Welfringer, Bruno; de Repentigny, Carl; Zagury, Gerald J

    2013-08-01

    Exposure to mercury (Hg)-contaminated soils may pose a health risk to children by way of oral, dermal, and inhalatory pathways. However, risk characterization studies, including contaminant bioaccessibility with child-specific exposure parameters and scenarios, are lacking. The objectives of this study were (1) to assess children's Hg exposure using characterization and oral bioaccessibility data from Hg-contaminated soils characterized in previous studies (n = 8); and (2) to characterize probabilistic risk in terms of hazard index (HI) considering ingestion, dermal, and inhalation pathways. Total Hg concentrations in soils ranged from 2.61 to 1.15 × 10(4) mg kg(-1). For moderately contaminated soils (S1-S5: Hg ≤ 12.15 mg kg(-1)), low oral bioaccessibility values (1.5-7.5 %) lead to HI < 1 in all scenarios. However, exposure to highly contaminated soils (S6-S8) may pose serious risks to children under normal exposure (HI 0.89-66.5) and soil-pica behaviour scenarios (HI up to 131). All three pathways significantly contributed to the risk. Using total Hg concentrations in calculations (assuming 100 % bioavailability) instead of considering Hg bioavailability leads to risk overestimation. Further research on oral, inhalatory, and dermal bioavailability of Hg, as well as child play behaviour, is recommended to obtain more accurate risk estimates. PMID:23546335

  8. 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. PMID:18709925

  9. 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

  10. Performance of different assessment methods to evaluate contaminant sources and fate in a coastal aquifer.

    PubMed

    Sbarbati, C; Colombani, N; Mastrocicco, M; Aravena, R; Petitta, M

    2015-10-01

    The present study deals with the application of different monitoring techniques and numerical models to characterize coastal aquifers affected by multiple sources of contamination. Specifically, equivalent freshwater heads in 243 monitoring wells were used to reconstruct the piezometric map of the studied aquifer; flow meter tests were carried out to infer vertical groundwater fluxes at selected wells; deuterium and oxygen isotopes were used to identify the groundwater origin, and tritium was analyzed to estimate the residence time; compound-specific isotope analyses and microbial analyses were employed to track different sources of contamination and their degradation; numerical modelling was used to estimate and verify groundwater flow direction and magnitude throughout the aquifer. The comparison of the information level for each technique allowed determining which of the applied approaches showed the best results to locate the possible sources and better understanding of the fate of the contaminants. This study reports a detailed site characterization process and outcomes for a coastal industrial site, where a comprehensive conceptual model of pollution and seawater intrusion has been built using different assessment methods. Information and results from this study encourages combining different methods for the design and implementation of the monitoring activities in real-life coastal contaminated sites in order to develop an appropriate strategy for control and remediation of the contamination. PMID:26006074

  11. Chemical contamination assessment of Gulf of Mexico oysters in response to hurricanes Katrina and Rita.

    PubMed

    Johnson, W E; Kimbrough, K L; Lauenstein, G G; Christensen, J

    2009-03-01

    Hurricane Katrina made landfall on August 29, 2005 and caused widespread devastation along the central Gulf Coast states. Less than a month later Hurricane Rita followed a similar track slightly west of Katrina's. A coordinated multi-agency response followed to collect water, sediment and tissue samples for a variety of chemical, biological and toxicological indicators. The National Oceanic and Atmospheric Administration's National Status and Trends Program (NS&T) participated in this effort by measuring chemical contamination in sediment and oyster tissue as part of the Mussel Watch Program, a long-term monitoring program to assess spatial and temporal trends in a wide range of coastal pollutants. This paper describes results for contaminants measured in oyster tissue collected between September 29 and October 10, 2005 and discusses the results in the context of Mussel Watch and its 20-year record of chemical contamination in the region and the nation. In general, levels of metals in oyster tissue were higher then pre- hurricane levels while organic contaminants were at or near record lows. No contaminant reported here exceeded the FDA action level for food safety. PMID:19051046

  12. Assessment of concentrations and effects of organohalogen contaminants in a terrestrial passerine, the European starling.

    PubMed

    Eng, Margaret L; Williams, Tony D; Letcher, Robert J; Elliott, John E

    2014-03-01

    European starlings (Sturnus vulgaris) are a valuable model species for the assessment of concentrations and effects of environmental contaminants in terrestrial birds. Polybrominated diphenyl ethers (PBDEs) are found in birds throughout the world, but relatively little is known of their concentrations or effects in free-living terrestrial passerines. We used a nest box population of European starlings to 1) measure the variation in egg concentrations of persistent organohalogen contaminants at an agricultural site, and 2) assess whether individual variation in PBDE concentrations in eggs was related to reproductive parameters, as well as maternal or nestling characteristics including body condition, thyroid hormones, oxidative stress, and hematocrit. As PBDEs were the main contaminant class of interest, we only assessed a subset of eggs for other organohalogen contaminants to establish background concentrations. Exposure to organohalogen contaminants was extremely variable over this relatively small study area. Geometric mean wet weight concentrations (range in brackets) of the major contaminants were 36.5 (12-174) ng/g ΣDDT (n=6 eggs) and 10.9 (2-307) ng/g ΣPBDEs (n=14). ΣPCBs at 3.58 (1.5-6.4) ng/g (n=6) were lower and less variable. There were low levels of other organochlorine (OC) pesticides such as dieldrin (2.02 ng/g), chlordanes (1.11 ng/g) and chlorobenzenes (0.23 ng/g). The only form of DDT detected was p,p'-DDE. The congener profiles of PBDEs and PCBs reflect those of industrial mixtures (i.e. DE-71, Aroclors 1254, 1260 and 1262). For all of the contaminant classes, concentrations detected in eggs at our study site were below levels previously reported to cause effects. Due to small sample sizes, we did not assess the relationship between ΣPCBs or ΣOCs and adult or chick condition. We observed no correlative relationships between individual variation in PBDE concentrations in starling eggs and reproductive success, maternal condition, or nestling

  13. Gastrointestinal campylobacteriosis in industrialised countries: comparison of the disease situation with salmonellosis, and microbiological contamination assessment.

    PubMed

    Laroche, M; Magras, C

    2013-12-01

    The science-based assessment of foodborne zoonotic risk is used to evaluate the public health impact of a hazard and to guide public decision-making on control measures. Key information for the hazard characterisation and microbiological contamination assessment phases of risk assessment may be obtained from the collection and structured statistical analysis of international data. This approach was used for the hazard characterisation phase of a risk assessment of gastrointestinal campylobacteriosis and salmonellosis in 30 industrialised countries over the period 2005-2009. The results showed an overall increase in the annual ratio campylobacteriosis/salmonellosis (R(moy) > 2), despite significant differences among countries (P < 0.0001). For countries with complete data over 20 years, the results showed significantly higher exposure to campylobacteriosis among certain population segments (men, children under 5 years of age and adults aged between 20 and 30), as well as in summer. A number of paired factors (Campylobacter species/animal species-meat type) are observed in this consumer exposure. However, the overall rate of bacterial transfer in meat supply chains varies widely, with far lower values for cattle (0.16) and pigs (0.24) than for poultry (0.60) and chickens (1.17). A lack of harmonised epidemiological data on the contamination status of foodstuffs (frequency, level, site, and species) further hampers the accurate identification of critical points of contamination and of the spread of the hazard throughout the food chain. PMID:24761724

  14. 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.

  15. 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). PMID:22632631

  16. Assessment of the effects of Cr, Cu, Ni and Pb soil contamination by ecotoxicological tests.

    PubMed

    Maisto, Giulia; Manzo, Sonia; De Nicola, Flavia; Carotenuto, Rita; Rocco, Annamaria; Alfani, Anna

    2011-11-01

    This study aimed to assess soil quality by chemical and ecotoxicological investigations and to check the correspondence between soil metal concentrations and ecotoxicity. For these purposes, surface soils collected at four adjacent roadside urban parks and at a former industrial area were characterized for C/N, organic matter content, texture, and pH. Cr, Cu, Ni and Pb, chosen among the most representative soil metal contaminants, were measured as total content and as available and water soluble fractions. In addition, the total concentrations of the investigated metals were used to calculate two chemical indices: the contamination and the potential ecological risk factors. The toxicity of the investigated soils was evaluated by an ecotoxicity test battery carried out on both soil samples (Vibrio fischeri, Heterocypris incongruens and Sinapis alba) and elutriates (Vibrio fischeri, Daphnia magna and Selenastrum capricornutum). The findings, both by the chemical and ecotoxicological approaches, would suggest that the soils with high metal contamination pose ecological risks. On the other hand, moderately metal contaminated soils did not exclude soil ecotoxicity. In fact, toxic effects were also highlighted in soils with low metal content, toxicity being affected by metal availability and soil characteristics. Moreover, the results suggest the importance of using a battery of tests to assess soil ecotoxicity. PMID:21918769

  17. Assessment of Environmental Contamination and Environmental Decontamination Practices within an Ebola Holding Unit, Freetown, Sierra Leone

    PubMed Central

    Youkee, Daniel; Brown, Colin S.; Lilburn, Paul; Shetty, Nandini; Brooks, Tim; Simpson, Andrew; Bentley, Neil; Lado, Marta; Kamara, Thaim B.; Walker, Naomi F.; Johnson, Oliver

    2015-01-01

    Evidence to inform decontamination practices at Ebola holding units (EHUs) and treatment centres is lacking. We conducted an audit of decontamination procedures inside Connaught Hospital EHU in Freetown, Sierra Leone, by assessing environmental swab specimens for evidence of contamination with Ebola virus by RT-PCR. Swabs were collected following discharge of Ebola Virus Disease (EVD) patients before and after routine decontamination. Prior to decontamination, Ebola virus RNA was detected within a limited area at all bedside sites tested, but not at any sites distant to the bedside. Following decontamination, few areas contained detectable Ebola virus RNA. In areas beneath the bed there was evidence of transfer of Ebola virus material during cleaning. Retraining of cleaning staff reduced evidence of environmental contamination after decontamination. Current decontamination procedures appear to be effective in eradicating persistence of viral RNA. This study supports the use of viral swabs to assess Ebola viral contamination within the clinical setting. We recommend that regular refresher training of cleaning staff and audit of environmental contamination become standard practice at all Ebola care facilities during EVD outbreaks. PMID:26692018

  18. An evaluation of the effectiveness of utilizing bioassays in the assessment of contaminated sites

    SciTech Connect

    Mroz, R.; Carter, J.; Tay, K.L.; Doe, K.

    1995-12-31

    The purpose of this study was to evaluate the battery of biological tests recommended by Environment Canada in the document ``A Review of Whole Organism Bioassays for Assessing the Quality of Soil, Freshwater Sediment and Freshwater in Canada`` for the assessment of contaminated sites. Soil and sediment samples were collected from three contaminated sites in the Atlantic Region and subjected to biological and chemical tests. Four bioassays were conducted on the soil samples: lettuce (Lactuca sativa) seedling emergence, algal (Selenastrum capricornutum) population growth inhibition, earthworm (Eisenia andrel) survival and inhibition of light output in Microtox (Vibrio fischeri). Soil samples collected from Makinsons, Newfoundland had elevated levels of PCBs, total petroleum hydrocarbons (TPH) and heavy metals and showed some toxicity in the algal population growth inhibition test. Samples from the Weldon, New Brunswick site were high in TPH and were marginally toxic to Microtox and lettuce seedlings. The earthworm survival test did not appear sensitive to any of the contaminated soil samples. Freshwater sediment samples, collected from Five Island Lake, Nova Scotia had elevated PCB and heavy metal concentrations. These samples underwent four biological tests: midge (Chironomus tentans) survival, amphipod (Hyalella azteca) survival, algal population growth inhibition and Microtox. At 100% concentration, the sediment was toxic to the first three species, with toxicities ranging from marginal to high. For all samples, the bioassay results were compared to chemical analyses and, in most cases, there was a positive correlation between contaminant concentrations and toxicity.

  19. Baseline risk assessment of groundwater contamination at the Uranium Mill Tailings Site near Gunnison, Colorado. Revision 1

    SciTech Connect

    Not Available

    1994-04-01

    This report evaluates potential impacts to public health or the environment resulting from groundwater contamination at the former uranium mill processing site. The tailings and other contaminated material at this site are being placed in an off-site disposal cell by the US Department of Energy`s (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project. Currently, the UMTRA Project is evaluating groundwater contamination. This is the second risk assessment of groundwater contamination at this site. The first risk assessment was performed primarily to evaluate existing domestic wells to determine the potential for immediate human health and environmental impacts. This risk assessment evaluates the most contaminated groundwater that flows beneath the processing site towards the Gunnison River. The monitor wells that have consistently shown the highest concentration of most contaminants are used in this risk assessment. This risk assessment will be used in conjunction with additional activities and documents to assist in determining what remedial action is needed for contaminated groundwater at the site after the tailings are relocated. This risk assessment follows an approach outlined by the US Environmental Protection Agency (EPA). The first step is to evaluate groundwater data collected from monitor wells at the site. Evaluation of these data showed that the main contaminants in the groundwater are cadmium, cobalt, iron, manganese, sulfate, uranium, and some of the products of radioactive decay of uranium.

  20. 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

  1. Toxicity assessment of xenobiotic contaminated groundwater using lux modified Pseudomonas fluorescens.

    PubMed

    Boyd, E M; Killham, K; Wright, J; Rumford, S; Hetheridge, M; Cumming, R; Meharg, A A

    1997-11-01

    A bacterial bioassay, suitable for rapid screening to assess the relative toxicity of xenobiotic contaminated groundwater has been developed. The quantitative bioassay utilizes a decline in luminescence of the lux marked soil bacterium Pseudomonas fluorescens on exposure to contaminated groundwaters from which effective concentration (EC) values can be assessed and compared. P. fluorescens was most sensitive to semivolatile organics in groundwaters but there was no correlation between EC value and chemical content. The sensitivity and reproducibility of the P. fluorescens bioassay was compared with that of Microtox and results showed that mean EC50 values for diluted ground water replicate samples were 20% and 18% respectively. This suggested that the P. fluorescens bioassay was as applicable to groundwater screening as the widely used Microtox bioassay. PMID:9353912

  2. Abundance and diversity of n-alkane-degrading bacteria in a forest soil co-contaminated with hydrocarbons and metals: a molecular study on alkB homologous genes.

    PubMed

    Pérez-de-Mora, Alfredo; Engel, Marion; Schloter, Michael

    2011-11-01

    Unraveling functional genes related to biodegradation of organic compounds has profoundly improved our understanding of biological remediation processes, yet the ecology of such genes is only poorly understood. We used a culture-independent approach to assess the abundance and diversity of bacteria catalyzing the degradation of n-alkanes with a chain length between C(5) and C(16) at a forest site co-contaminated with mineral oil hydrocarbons and metals for nearly 60 years. The alkB gene coding for a rubredoxin-dependent alkane monooxygenase enzyme involved in the initial activation step of aerobic aliphatic hydrocarbon metabolism was used as biomarker. Within the area of study, four different zones were evaluated: one highly contaminated, two intermediately contaminated, and a noncontaminated zone. Contaminant concentrations, hydrocarbon profiles, and soil microbial respiration and biomass were studied. Abundance of n-alkane-degrading bacteria was quantified via real-time PCR of alkB, whereas genetic diversity was examined using molecular fingerprints (T-RFLP) and clone libraries. Along the contamination plume, hydrocarbon profiles and increased respiration rates suggested on-going natural attenuation at the site. Gene copy numbers of alkB were similar in contaminated and control areas. However, T-RFLP-based fingerprints suggested lower diversity and evenness of the n-alkane-degrading bacterial community in the highly contaminated zone compared to the other areas; both diversity and evenness were negatively correlated with metal and hydrocarbon concentrations. Phylogenetic analysis of alkB denoted a shift of the hydrocarbon-degrading bacterial community from Gram-positive bacteria in the control zone (most similar to Mycobacterium and Nocardia types) to Gram-negative genotypes in the contaminated zones (Acinetobacter and alkB sequences with little similarity to those of known bacteria). Our results underscore a qualitative rather than a quantitative response of

  3. Assessment and modelling of heavy metal contamination from Madneuli open-pit mine, Georgia

    NASA Astrophysics Data System (ADS)

    Tchelidze, T.; Melikadze, G.; Leveinen, J.; Kaija, J.; Kumpalainen, S.

    2003-04-01

    Acid mine drainage from banked waste rocks (150 million m^3) and sulfide ore tailings of the Madneuli Cu-Au open-pit mine have created major environmental pollution problem in Bolnisi district, Georgia. Intensive leaching of exposed rocks and direct discharge of mine waters to nearby watercourses have lead to strong heavy metal pollution of groundwater and Rivers Kazretula, Poladauri and Mashavera. Increased concentrations of Cu, Zn, Pb, Ni, Mn, Cr, Cd and Hg exceeding maximum permissible values by 3-2000 times, are registered almost everywhere. Polluted surface waters are used intensively for irrigation. Besides, contaminated groundwater is pumped for irrigation and drinking water supply in alluvial deposits along the rivers. Because the spread of contamination is a slow process, the adverse health effects may not yet have emerged in the investigation area. The transport modelling was used in the framework of risk assessment to estimate the direction, rate and extent of chemical migration in the contaminated site in order to support environmental management and decisionmaking involving identification of high-risk areas, protection from pollutants, and planning of remediation work. Geochemical and contamination transport modelling conducted in this study suggest that the present contamination levels will eventually reach the total investigation area causing serious health risks to the local population in long terms. Mineral lifetime estimates suggest that the contamination might continue for centuries with current pollution loads. Furthermore, geochemical modelling showed that there is no reason to expect the natural attenuation of the contamination. The potential impacts of preventive actions were studied by preparing a model scenario where the present heavy metal contamination level was lowered to 0.1 mg/l in two streams entering the model area. The model results suggest that within 5 years, already significant reduction of concentrations can be reached. The

  4. Molecular assessment of disease states in kidney transplant biopsy samples.

    PubMed

    Halloran, Philip F; Famulski, Konrad S; Reeve, Jeff

    2016-09-01

    Progress in renal transplantation requires improved understanding and assessment of rejection and injury. Study of the relationship between gene expression and clinical phenotypes in kidney transplant biopsy samples has led to the development of a system that enables diagnoses of specific disease states on the basis of messenger RNA levels in the biopsy sample. Using this system we have defined the molecular landscape of T cell-mediated rejection (TCMR), antibody-mediated rejection (ABMR), acute kidney injury (AKI), and tubular atrophy and interstitial fibrosis. TCMR and ABMR share IFNγ-mediated effects and TCMR has emerged as a cognate T cell-antigen presenting cell process in the interstitium, whereas ABMR is a natural-killer-cell-mediated process that occurs in the microcirculation. The specific features of these different processes have led to the creation of classifiers to test for TCMR and ABMR, and revealed that ABMR is the principal cause of kidney transplant deterioration. The molecular changes associated with renal injury are often more extensive than suggested by histology and indicate that the progression to graft failure is caused by continuing nephron injury, rather than fibrogenesis. In summary, advances in the molecular assessment of disease states in biopsy samples has improved understanding of specific processes involved in kidney graft outcomes. PMID:27345248

  5. Improvement of modelling capabilities for assessing urban contamination : The EMRAS Urban Remediation Working Group.

    SciTech Connect

    Thiessen, K. M.; Batandjieva, B.; Andersson, K. G.; Arkhipov, A.; Charnock, T. W.; Gallay, F.; Gaschak, S.; Golikov, V.; Hwang, W. T.; Kaiser, J. C.; Kamboj, S.; Steiner, M.; Tomas, J.; Trifunovic, D.; Yu, C.; Ziemer, R. L.; Zlobenko, B.; Environmental Science Division; SENES Oak Ridge; IAEA; Riso National Lab.; Chernobyl Center for Nuclear Safety; Health Protection Agency; IRSN; Inst. of Radiation Hygene of the Ministry of Public Health, Russian Federation; KAERI, Republic of Korea; GSF, Germany; BfS, Germany; CPHR, Cuba; State Office for Radiation Protection, Croatia; AECL, Canada; National Academy of Science, Ukraine

    2008-01-01

    The Urban Remediation Working Group of the International Atomic Energy Agency's Environmental Modeling for Radiation Safety (EMRAS) programme was established to improve modeling and assessment capabilities for radioactively contaminated urban situations, including the effects of countermeasures. An example of the Working Group's activities is an exercise based on Chernobyl fallout data in Ukraine, which has provided an opportunity to compare predictions among several models and with available measurements, to discuss reasons for discrepancies, and to identify areas where additional information would be helpful.

  6. Assessment of water use for estimating exposure to tap water contaminants.

    PubMed

    Shimokura, G H; Savitz, D A; Symanski, E

    1998-02-01

    Epidemiological studies examining the association between exposure to tap water contaminants (such as chlorination by-products) and disease outcomes (such as cancer and adverse reproductive outcomes) have been limited by inaccurate exposure assessment. Failure to take into account the variation in beverage and tap water consumption and exposure to volatile contaminants through inhalation and dermal absorption can introduce misclassification in assessing the association between exposure to tap water contaminants and health. To refine exposure assessment of tap water contaminants, we describe in detail the tap water consumption, showering, and bathing habits of pregnant women and their male partners as assessed by a questionnaire and a 3-day water diary. We found good agreement between questionnaire and 3-day water diary values for drinking water intake (Pearson's r = 0.78) and for time spent showering(r = 0.68) and bathing (r = 0.78). Half of the participants consumed tap water on a regular basis with an overall mean +/- 1 standard deviation (SD) of 0. 78 +/- 0.51 l/day. Our results further suggest that full-time employees, compared to women working part-time or less, have more heterogeneous consumption patterns over time. Seventy-nine percent of women and 94% of men took showers for an average of 11.6 +/-4.0 min and 10.4 +/- 4.8 min, respectively. Baths were taken more frequently by women than men (21% vs. 3%) for an average of 22.9 +/-10.1 min and 21.3 +/- 12.4 min, respectively. Thus, these patterns of tap water use should be considered in the design and interpretation of environmental epidemiology studies. PMID:9432970

  7. External quality assessment of BRAF molecular analysis in melanoma.

    PubMed

    Deans, Zandra C; Wallace, Andrew; O'Sullivan, Brendan; Purvis, Andrew; Camus, Suzanne; Fairley, Jennifer A; Gonzalez, David

    2014-02-01

    The availability of BRAF inhibitors has given metastatic melanoma patients an effective new treatment choice and molecular testing to determine the presence or absence of a BRAF codon 600 mutation is pivotal in the clinical management of these patients. This molecular test must be performed accurately and appropriately to ensure that the patient receives the most suitable treatment in a timely manner. Laboratories have introduced such testing; however, some experience low sample throughput making it critical that an external quality assurance programme is available to help promote a high standard of testing, reporting and provide an educational aspect for BRAF molecular testing. Laboratories took part in three rounds of external quality assessment (EQA) during a 12-month period giving participants a measure of the accuracy of genotyping, clinical interpretation of the result and experience in testing a range of different samples. Formalin fixed paraffin embedded tissue sections from malignant melanoma patients were distributed to participants for BRAF molecular testing. The standard of testing was generally high but distribution of a mutation other than the most common, p.(Val600Glu), highlighted concerns with detection or reporting of the presence of rarer mutations. The main issues raised in the interpretation of the results were the importance of clear unambiguous interpretation of the result tailored to the patient and the understanding that the treatment is different from that given to other stratified medicine programmes. The variability in reporting and wide range of methodologies used indicate a continuing need for EQA in this field. PMID:24098023

  8. 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.

  9. Improving Modeling of Iodine-129 Groundwater Contamination Plumes Using the System Assessment Capability

    SciTech Connect

    Dirkes, J.; Nichols, W.E.; Wurstner, S.K.

    2004-01-01

    Years of production of radioactive materials at the Hanford Site in southeastern Washington State has resulted in contamination of surface, subsurface, and surface water environments. Cleanup of the site has been aided by various tools, including computer software used to predict contaminant migration in the future and estimate subsequent impacts. The System Assessment Capability (SAC) is a total systems tool designed to simulate the movement of contaminants from all waste sites at Hanford through the vadose zone, the unconfined aquifer, and the Columbia River. Except for iodine-129, most of the contaminants modeled by SAC have acceptably matched field measurements. The two most likely reasons for the inconsistency between the measured field data and SAC modeled predictions are an underestimated inventory and an overestimated sorption value (Kd). Field data tend to be point measurements taken from near the surface of the unconfined aquifer. Thus, the depth of the iodine-129 contamination plume on the site is not well characterized. Geostatistical analyses of the measured data were conducted to determine the mass of iodine-129 for four assumed plume depths within the unconfined aquifer. Several simulations for two different Kd’s using the initial SAC inventory were run to determine the effect of an overestimated sorption value on SAC modeled predictions. The initial SAC inventory was then increased for the two different Kd’s to determine the influence of an underestimated inventory on SAC modeled predictions. It was found that evidence for both an underestimated inventory and for an overestimated sorption value for iodine-129 exist. These results suggest that the Kd for iodine-129 should be reevaluated and that a more complete inventory must be generated in order to more accurately model iodine-129 groundwater contamination plumes that match available field data.

  10. Assessment of coastal storm impacts on contaminant body burdens of oysters collected from the Gulf of Mexico.

    PubMed

    Apeti, Dennis A; Lauenstein, Gunnar G; Christensen, John D; Johnson, Edward W; Mason, Andrew

    2011-10-01

    This study evaluated changes in oyster tissue contaminant levels following North Atlantic tropical cyclones to determine if changes in contaminant concentrations were predictable. The basis for this study was analysis of coastal chemical contaminant data from the National Oceanic and Atmospheric Administration's (NOAA) National Status and Trends Mussel Watch Program and NOAA's National Weather Service storm track data. The tendency for contaminant (metals and organic compounds) body burdens to increase or decrease in oyster tissue after a storm was assessed using contingency and correspondence analyses. Post-storm contaminant levels in oysters revealed a consistent pattern of distribution, which could be described as follows: (1) most of the organic contaminants stay within their long-term concentration ranges, (2) very few organic contaminants decreased, and (3) metals overwhelmingly tend to increase. PMID:21193956

  11. A street deposit sampling method for metal and hydrocarbon contamination assessment.

    PubMed

    Bris, F J; Garnaud, S; Apperry, N; Gonzalez, A; Mouchel, J M; Chebbo, G; Thévenot, D R

    1999-09-01

    Urban surface contamination, by atmospheric deposits as well as human activities, is a major concern for urban pollution management. Besides coarse street deposits which are clearly perceived and easily removed, suspended solid (SS) surface loads and contamination by heavy metals and hydrocarbons are rarely assessed although they could be of major importance with regards to combined or separate server overflow (CSO and SSO) impacts. Both dry and wet vacuum sampling procedures have been first compared, in the laboratory, using dry and sieved clay or street deposits. Then the wet vacuum sampling procedure has been refined, coupling the injection of water and the hand-brushing of the surface prior to its vacuum cleaning, and evaluated on a car parking area close to the University. Finally this procedure has been assessed in Béarn Street within the 'Le Marais' district in Paris centre, and 34 samples have been analysed for metal and eight for aromatic hydrocarbon contamination. Heavy metal concentrations (0.1-1.7 g kg-1 dry wt. Cu, 0.9-6.1 g kg-1 dry wt. Pb and 1.5-4.6 g kg-1 dry wt. Zn) within street deposit samples collected in Paris centre, indicate a high contamination, especially for copper and zinc, as compared to reported data. Total polyaromatic hydrocarbons (PAHs) are in the 3-11 mg kg-1 dry wt. range, thus approximately 10 times less contaminated than dry atmospheric deposits. This paper presents data obtained and discusses the difficulties encountered when sampling street deposits in busy areas of a city like Paris. The water jet street cleaning procedure used by Paris city workers was tested for its efficiency, by comparison of surface loads before and after the cleaning procedure. Although solids cleaning efficiency is highly variable (20-65%) and somewhat higher for particles larger than 100 microns, particulate metal cleaning efficiency is even more variable (0-75%) and particulate PAHs appear not to be significantly removed. PMID:10535121

  12. 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

  13. A spatial risk assessment methodology to support the remediation of contaminated land.

    PubMed

    Carlon, Claudio; Pizzol, Lisa; Critto, Andrea; Marcomini, Antonio

    2008-04-01

    When soil and groundwater contaminations occur over large areas, remediation measures should be spatially prioritized on the basis of the risk posed to human health and in compliance with technological and budget constraints. Within this scope, the application of human health risk assessment algorithms in a spatially resolved environment raises a number of methodological and technical complexities. In this paper, a methodology is proposed and applied in a case study to support the entire formulation process of remediation plans, encompassing hazard assessment, exposure assessment, risk characterisation, uncertainty assessment and allocation of risk reduction measures. In the hazard assessment, it supports the selection of Contaminants of Concern (CoC) with regard to both their average concentrations and peak concentrations, i.e. hot spots. In the exposure assessment, it provides a zoning of the site based on the geostatistical mapping of contaminant. In the risk characterisation, it generates vector maps of Risk Factors on the basis of the risk posed by multiple substances and allows the interrogation of most relevant CoC and exposure pathways for each zone of the site. It also supports the Monte Carlo based probabilistic estimation of the Risk Factors and generates maps of the associated uncertainty. In the risk reduction phase, it supports the formulation of remediation plans based on the stepwise spatial allocation of remediation interventions and the on-time simulation of risk reduction performances. The application of this methodology is fully supported by an easy-to-use and customized Geographical Information System and does not require high expertise for interpretation. The proposed methodology is the core module of a Decision Support System (DSS) that was implemented in the DESYRE software aimed at supporting the risk-based remediation of megasites. PMID:18031816

  14. Dead or Alive: Molecular Assessment of Microbial Viability

    PubMed Central

    Meschke, John S.

    2014-01-01

    Nucleic acid-based analytical methods, ranging from species-targeted PCRs to metagenomics, have greatly expanded our understanding of microbiological diversity in natural samples. However, these methods provide only limited information on the activities and physiological states of microorganisms in samples. Even the most fundamental physiological state, viability, cannot be assessed cross-sectionally by standard DNA-targeted methods such as PCR. New PCR-based strategies, collectively called molecular viability analyses, have been developed that differentiate nucleic acids associated with viable cells from those associated with inactivated cells. In order to maximize the utility of these methods and to correctly interpret results, it is necessary to consider the physiological diversity of life and death in the microbial world. This article reviews molecular viability analysis in that context and discusses future opportunities for these strategies in genetic, metagenomic, and single-cell microbiology. PMID:25038100

  15. Baseline risk assessment of ground water contamination at the Uranium Mill Tailings Site near Grand Junction, Colorado

    SciTech Connect

    Not Available

    1994-06-01

    This Baseline Risk Assessment of Ground Water Contamination at the Uranium Mill Tailings Site Near Grand Junction, Colorado evaluates potential impacts to public health or the environment resulting from ground water contamination at the former uranium mill processing site. The tailings and other contaminated material at this site were placed in an off-site disposal cell by the US Department of Energy`s (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project. The remedial activities at the site were conducted from 1989 to 1993. Currently, the UMTRA Project is evaluating ground water contamination. This risk assessment is the first document specific to this site for the Ground Water Project. This risk assessment evaluates the most contaminated ground water that flows beneath the processing site toward the Colorado River. The monitor wells that have consistently shown the highest concentrations of most contaminants are used to assess risk. This risk assessment will be used in conjunction with additional activities and documents to determine what remedial action may be needed for contaminated ground water at the site. This risk assessment follows an approach outlined by the EPA. the first step is to evaluate ground water data collected from monitor wells at the site. Evaluation of these data showed that the contaminants of potential concern in the ground water are arsenic, cadmium, cobalt, fluoride, iron, manganese, molybdenum, nickel, sulfate, uranium, vanadium, zinc, and radium-226. The next step in the risk assessment is to estimate how much of these contaminants people would be exposed to if they drank from a well installed in the contaminated ground water at the former processing site.

  16. Assessing Metal Contamination in Lead Arsenate Contaminated Orchard Soils Using Near and Mid-Infrared Diffuse Reflectance Spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Historic use of lead-arsenate as pesticide in apple orchards left many soils contaminated with arsenic (As) and lead (Pb). Notorious health effects and their severe soil contamination are of primary concerns for major regulatory agencies, and community at large. Wet chemistry methods for soil anal...

  17. 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.

  18. Baseline risk assessment of ground water contamination at the Uranium Mill Tailings Sites near Slick Rock, Colorado. Revision 1

    SciTech Connect

    1995-09-01

    Two UMTRA (Uranium Mill Tailings Remedial Action) Project sites are near Slick Rock, Colorado: the North Continent site and the Union Carbide site. Currently, no one uses the contaminated ground water at either site for domestic or agricultural purposes. However, there may be future land development. This risk assessment evaluates possible future health problems associated with exposure to contaminated ground water. Since some health problems could occur, it is recommended that the contaminated ground water not be used as drinking water.

  19. Baseline risk assessment of ground water contamination at the Uranium Mill Tailings Site near Green River, Utah

    SciTech Connect

    Not Available

    1994-09-01

    This document evaluates potential impacts to public health and the environment resulting from ground water contamination at the former uranium mill processing site. The tailings and other contaminated material at this site were placed in a disposal cell on the site in 1989 by the US DOE`s Uranium Mill Tailings Remedial Action (UMTRA) Project. Currently, UMTRA Project is evaluating ground water contamination in this risk assessment.

  20. Molecular analysis of phosphate limitation in Geobacteraceae during the bioremediation of a uranium-contaminated aquifer

    SciTech Connect

    N'Guessan, L.A.; Elifantz, H.; Nevin, K.P.; Mouser, P.J.; Methe, B.; Woodard, T. L.; Manley, K.; Williams, K. H.; Wilkins, M. J.; Larsen, J.T.; Long, P. E.; Lovley, D. R.

    2009-09-01

    Nutrient limitation is an environmental stress that may reduce the effectiveness of bioremediation strategies, especially when the contaminants are organic compounds or when organic compounds are added to promote microbial activities such as metal reduction. Genes indicative of phosphate-limitation were identified via microarray analysis of chemostat cultures of Geobacter sulfureducens. This analysis revealed that genes in the pst-pho operon, which is associated with a high affinity phosphate uptake system in other microorganisms, had significantly higher transcript abundance under phosphate-limiting conditions, with the genes pstB and phoU the most up-regulated. Quantitative PCR analysis of pstB and phoU transcript levels in G. sulfurreducens grown in chemostats demonstrated that the expression of these genes increased when phosphate was removed from the culture medium. Transcripts of pstB and phoU within the subsurface Geobacter species predominating during an in situ uranium bioremediation field experiment were more abundant than in chemostat cultures of G. sulfurreducens that were not limited for phosphate. Addition of phosphate to incubations of subsurface sediments did not stimulate dissimilatory metal reduction. The added phosphate was rapidly adsorbed onto the sediments. The results demonstrate that Geobacter species can effectively reduce U(VI) even when experiencing suboptimal phosphate concentrations and that increasing phosphate availability with phosphate additions is difficult to achieve due to the high reactivity of this compound. This transcript-based approach developed for diagnosing phosphate limitation should be applicable to assessing the potential need for additional phosphate in other bioremediation processes.

  1. Molecular Analysis of Phosphate Limitation in Geobacteraceae During the Bioremediation of a Uranium-Contaminated Aquifer

    SciTech Connect

    N'Guessan, A. Lucie; Elifantz, H.; Nevin, Kelly P.; Mouser, Paula; Methe, Barbara; Woodard, Trevor L.; Manley, Kimberley; Williams, Kenneth H.; Wilkins, Michael J.; Larsen, Joern T.; Long, Philip E.; Lovley, Derek R.

    2010-02-01

    Nutrient limitation is an environmental stress that may reduce the effectiveness of bioremediation strategies, especially when the contaminants are organic compounds or when organic compounds are added to promote microbial activities such as metal reduction. Genes indicative of phosphate-limitation were identified via microarray analysis of chemostat cultures of Geobacter sulfureducens. This analysis revealed that genes in the pst-pho operon, which is associated with a high affinity phosphate uptake system in other microorganisms, had significantly higher transcript abundance under phosphate-limiting conditions, with the genes pstB and phoU the most up-regulated. Quantitative PCR analysis of pstB and phoU transcript levels in G. sulfurreducens grown in chemostats demonstrated that the expression of these genes increased when phosphate was removed from the culture medium. Transcripts of pstB and phoU within the subsurface Geobacter species predominating during an in situ uranium bioremediation field experiment were more abundant than in chemostat cultures of G. sulfurreducens that were not limited for phosphate. Addition of phosphate to incubations of subsurface sediments did not stimulate dissimilatory metal reduction. The added phosphate was rapidly adsorbed onto the sediments. The results demonstrate that Geobacter species can effectively reduce U(VI) even when experiencing suboptimal phosphate concentrations and that increasing phosphate availability with phosphate additions is difficult to achieve due to the high reactivity of this compound. This transcript-based approach developed for diagnosing phosphate limitation should be applicable to assessing the potential need for additional phosphate in other bioremediation processes.

  2. Molecular analysis of phosphate limitation in Geobacteraceae during the bioremediation of a uranium-contaminated aquifer

    SciTech Connect

    N'Guessan, A. Lucie; Elifantz, H.; Nevin, Kelly P.; Mouser, Paula; Methe, Barbara; Woodard, Trevor L.; Manley, Kimberley; Williams, Kenneth H.; Wilkins, Michael J.; Larsen, Joern T.; Long, Philip E.; Lovley, Derek R.

    2010-01-10

    Nutrient limitation is an environmental stress that may reduce the effectiveness of bioremediation strategies, especially when the contaminants are organic compounds or when organic compounds are added to promote microbial activities such as metal reduction. Genes indicative of phosphatelimitation were identified by microarray analysis of chemostat cultures of Geobacter sulfureducens. This analysis revealed that genes in the pst-pho operon, which is associated with a high-affinity phosphate uptake system in other microorganisms, had significantly higher transcript abundance under phosphate-limiting conditions, with the genes pstB and phoU upregulated the most. Quantitative PCR analysis of pstB and phoU transcript levels in G. sulfurreducens grown in chemostats demonstrated that the expression of these genes increased when phosphate was removed from the culture medium. Transcripts of pstB and phoU within the subsurface Geobacter species predominating during an in situ uranium-bioremediation field experiment were more abundant than in chemostat cultures of G. sulfurreducens that were not limited for phosphate. Addition of phosphate to incubations of subsurface sediments did not stimulate dissimilatory metal reduction. The added phosphate was rapidly adsorbed onto the sediments. The results demonstrate that Geobacter species can effectively reduce U(VI) even when experiencing suboptimal phosphate concentrations and that increasing phosphate availability with phosphate additions is difficult to achieve because of the high reactivity of this compound. This transcript-based approach developed for diagnosing phosphate limitation should be applicable to assessing the potential need for additional phosphate in other bioremediation processes.

  3. Molecular-level processes governing the interaction of contaminants with iron and manganese oxides. 1997 annual progress report

    SciTech Connect

    Chambers, S.A.; Brown, G.

    1997-06-01

    'The central tenet of this proposal is that a fundamental understanding of specific mineral surface-site reactivities will substantially improve reactive transport models of contaminants in geologic systems, and will allow more effective remediation schemes to be devised. Most large-scale, macroscopic models employ global chemical reaction kinetics and thermochemistry. However, such models do not incorporate molecular-level input critical to the detailed prediction of how contaminants interact with minerals in the subsurface. A first step leading to the incorporation of molecular-level processes in large-scale macroscopic models is the ability to understand which molecular-level processes will dominate the chemistry at the microscopic grain level of minerals. To this end, the research focuses on the fundamental mechanisms of redox chemistry at mineral surfaces. As much of this chemistry in sediments involves the Fe(III)/Fe(II) and Mn(IV)/Mn(II) couples, the authors focus on mineral phases containing these species. Of particular interest is the effect of the local coordination environment of Fe and Mn atoms on their reactivity toward contaminant species. Studies of the impact of local atomic structure on reactivity in combination with knowledge about the types and amounts of various surfaces on natural grain- size minerals provide the data for statistical models. These models in turn form the basis of the larger-scale macroscopic descriptions of reactivity that are needed for reactive transport models. A molecular-level understanding of these mechanisms will enhance the ability to design much greater performance efficiency, cost effectiveness, and remediation strategies that have minimal negative impact on the local environment. For instance, a comprehensive understanding of how minerals that contain Fe(II) reduce oxyanions and chlorinated organics should enable the design of other Fe(II)-containing remediation materials in a way that is synergistic with existing

  4. Baseline risk assessment of ground water contamination at the Uranium Mill Tailings Site near Shiprock, New Mexico. Revision 1

    SciTech Connect

    Not Available

    1994-04-01

    This baseline risk assessment at the former uranium mill tailings site near Shiprock, New Mexico, evaluates the potential impact to public health or the environment resulting from ground water contamination at the former uranium mill processing site. The tailings and other contaminated material at this site were placed in an on-site disposal cell in 1986 through the US Department of Energy (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project. Currently, the UMTRA Project is evaluating ground water contamination. This risk assessment is the first document specific to this site for the Ground Water Project. There are no domestic or drinking water wells in the contaminated ground water of the two distinct ground water units: the contaminated ground water in the San Juan River floodplain alluvium below the site and the contaminated ground water in the terrace alluvium area where the disposal cell is located. Because no one is drinking the affected ground water, there are currently no health or environmental risks directly associated with the contaminated ground water. However, there is a potential for humans, domestic animals, and wildlife to the exposed to surface expressions of ground water in the seeps and pools in the area of the San Juan River floodplain below the site. For these reasons, this risk assessment evaluates potential exposure to contaminated surface water and seeps as well as potential future use of contaminated ground water.

  5. 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.

  6. 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

  7. Reducing uncertainty in ecological risk assessment: The pros of measuring contaminant exposures

    SciTech Connect

    Burris, J.A.; Pease, A.

    1995-12-31

    Wildlife species (mammals, birds and reptiles) are primarily exposed to contamination in soils via ingestion of food. Uncertainties in risk analyses for this pathway are largely associated with the estimation of the amount of contamination in food items. The benefits of measuring contaminant concentrations in food items are examined based on comparison of risk results with and without measurements of exposure. At two hazardous waste sites, plants and earthworms were analyzed for metals and organics. Site-specific bioaccumulation factors (BAFs) were calculated and compared to literature reported values. In general, the metals concentrations in plant samples were higher than those predicted by literature values with the exception of cadmium and copper. Metal concentrations measured in invertebrates (worms) were lower than those predicted by literature values with the exception of arsenic. Literature BAFs did not adequately predict concentrations of barium, mercury or copper in invertebrate tissue. In the ecological risk assessments for both of the sites, if site-specific measurements were used, risks for wildlife species were not predicted. However if literature BAF values were used, unacceptable risks were predicted. The higher estimates of risks were associated with overestimates of dietary exposures of lead, cadmium, chromium, copper and zinc. Measurement of contaminant exposures provided for a more realistic and cost-effective estimate of ecological risks. The effect of using the empirical data on the magnitude of risks were evaluated including decisions concerning remediation. A cost-benefit analysis will be provided comparing the costs of measurement of exposures versus remediation.

  8. Assessment of potential groundwater contamination sources in a wellhead protection area.

    PubMed

    Harman, W A; Allan, C J; Forsythe, R D

    2001-07-01

    Determining the human health dangers from potential contamination sources, within a wellhead protection area (WHPA), requires that a risk analysis be undertaken. In this study, a desktop geographic information system and spreadsheet software are used to implement an EPA risk screening methodology for WHPAs called 'Managing Ground Water Contamination Sources in Wellhead Protection Areas--A Priority Setting Approach'. The methodology was applied to a WHPA in Gaston County, North Carolina. Results indicate that the risk of well contamination from an interstate highway and gas station with old steel underground storage tanks were comparatively high. Medium risks included a thoroughfare and highway, while low risks were assigned to machine shops, a body shop, septic systems and a gas station with new underground storage tanks and secondary containment. A sensitivity analyses of the Priority Setting Approach indicated that risk scores were extremely sensitive to hydrogeologic variables such as hydraulic conductivity. It is recommended that risk assessors utilize a range of hydrogeologic parameters to assess overall risk from each potential contamination source. PMID:11475085

  9. Use of artificial oak log substrates to assess the impact of contaminants on soil macroinvertebrates

    SciTech Connect

    Henry, R.; Charters, D.W.

    1995-12-31

    Consideration of aquatic benthic macroinvertebrates can yield insight concerning the effects of chemical contamination on community structure and function. This approach has been used successfully to distinguish subtle changes in community response to water quality and watershed degradation. Analyses of this type however, has not been developed to the same extent for terrestrial soil macroinvertebrate communities. A number of factors, including sampling protocols and habitat variability, may inhibit efforts in this direction. An artificial substrate was developed that mimics a decaying oak log. These artificial logs are constructed of oak slats filled with various sized oak particles and measure approximately 7 cm x 7 cm x 30 cm. The substrates are deployed on the soil surface across a contaminant gradient and allowed to colonize. Following recovery, the logs are transported to a laboratory where they are disassembled, and the colonizers extracted for taxonomic, numeric, or other analyses. Since the artificial substrate community is a reflection of the endemic soil inhabitants, the results of this type of evaluation can be used in the assessment of ecological concerns associated with soil contamination. The practical and theoretical concerns of this method will be discussed along with the results of an initial trial at a metal contaminated site.

  10. Assessing spatial variability of soil petroleum contamination using visible near-infrared diffuse reflectance spectroscopy.

    PubMed

    Chakraborty, Somsubhra; Weindorf, David C; Zhu, Yuanda; Li, Bin; Morgan, Cristine L S; Ge, Yufeng; Galbraith, John

    2012-11-01

    Visible near-infrared (VisNIR) diffuse reflectance spectroscopy (DRS) is a rapid, non-destructive method for sensing the presence and amount of total petroleum hydrocarbon (TPH) contamination in soil. This study demonstrates the feasibility of VisNIR DRS to be used in the field to proximally sense and then map the areal extent of TPH contamination in soil. More specifically, we evaluated whether a combination of two methods, penalized spline regression and geostatistics could provide an efficient approach to assess spatial variability of soil TPH using VisNIR DRS data from soils collected from an 80 ha crude oil spill in central Louisiana, USA. Initially, a penalized spline model was calibrated to predict TPH contamination in soil by combining lab TPH values of 46 contaminated and uncontaminated soil samples and the first-derivative of VisNIR reflectance spectra of these samples. The r(2), RMSE, and bias of the calibrated penalized spline model were 0.81, 0.289 log(10) mg kg(-1), and 0.010 log(10) mg kg(-1), respectively. Subsequently, the penalized spline model was used to predict soil TPH content for 128 soil samples collected over the 80 ha study site. When assessed with a randomly chosen validation subset (n = 10) from the 128 samples, the penalized spline model performed satisfactorily (r(2) = 0.70; residual prediction deviation = 2.0). The same validation subset was used to assess point kriging interpolation after the remaining 118 predictions were used to produce an experimental semivariogram and map. The experimental semivariogram was fitted with an exponential model which revealed strong spatial dependence among soil TPH [r(2) = 0.76, nugget = 0.001 (log(10) mg kg(-1))(2), and sill 1.044 (log(10) mg kg(-1))(2)]. Kriging interpolation adequately interpolated TPH with r(2) and RMSE values of 0.88 and 0.312 log(10) mg kg(-1), respectively. Furthermore, in the kriged map, TPH distribution matched with the expected TPH variability of the study site. Since the

  11. 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

  12. Molecular tools to understand the bioremediation effect of plants and earthworms on contaminated marine sediments.

    PubMed

    Moreno, Beatriz; Cañizares, Rosa; Macci, Cristina; Doni, Serena; Masciandaro, Grazia; Benitez, Emilio

    2015-12-30

    A meso-scale pilot plant was set up to test the efficiency of a bioremediation scheme applied to marine sediments contaminated by heavy metals and hydrocarbons. The experiment was implemented for three years in two stages using two remediation agents: plants (Paspalum vaginatum and Tamarix gallica) and earthworms (Eisenia fetida). DNA and RNA-based methodologies were applied to elucidate the dynamics of the bacterial population and were related to improving biological and chemical conditions of the sediments. Bioremediation strategies were successful in removing pollutants from the contaminated sediments and specialization within the bacterial community related to the type of contamination present was detected in the different stages of the process. The highest response of Gram-positive PAH-degraders to the contamination was detected at the beginning and after the first stage of the experiment, corresponding to the uppermost values of degradation. PMID:26223013

  13. A contamination assessment of the CI carbonaceous meteorite Orgueil using a DNA-directed approach

    NASA Astrophysics Data System (ADS)

    Aerts, J. W.; Elsaesser, A.; RöLing, W. F. M.; Ehrenfreund, P.

    2016-05-01

    The Orgueil meteorite has become one of the most well-studied carbonaceous meteorites, after it fell in France 150 yr ago. Extraterrestrial organic compounds such as amino acids and nucleobases in the parts per billion ranges were identified in Orgueil samples with supporting isotopic analyses. However, speculations of terrestrial contamination such as organic inclusions in the form of microbes and seeds accompanied the analyses of the Orgueil meteorite ever since its fall. By using molecular analysis, we performed DNA extractions and spiking experiments combined with 16S and 18S rRNA gene targeted PCR amplification to quantify the level of terrestrial biocontamination. Our results indicate that terrestrial contamination with DNA was insignificant in the investigated meteorite fraction. We also remeasured and confirmed concentrations of amino acids found in previous studies and conclude that their rather high concentrations and distribution cannot be explained by terrestrial contamination with microorganisms alone. These results represent the first analysis using DNA-directed tools in the analysis of the Orgueil meteorite to determine trace levels of biomarkers.

  14. Risk Assessment of Radiation Exposure using Molecular Biodosimetry

    NASA Technical Reports Server (NTRS)

    Elliott, Todd F.; George, K.; Hammond, D. K.; Cucinotta, F. A.

    2007-01-01

    Current cytogenetic biodosimetry methods would be difficult to adapt to spaceflight operations, because they require toxic chemicals and a substantial amount of time to perform. In addition, current biodosimetry techniques are limited to whole body doses over about 10cGy. Development of new techniques that assess radiation exposure response at the molecular level could overcome these limitations and have important implications in the advancement of biodosimetry. Recent technical advances include expression profiling at the transcript and protein level to assess multiple biomarkers of exposure, which may lead to the development of a radiation biomarker panel revealing possible fingerprints of individual radiation sensitivity. So far, many biomarkers of interest have been examined in their response to ionizing radiation, such as cytokines and members of the DNA repair pathway. New technology, such as the Luminex system can analyze many biomarkers simultaneously in one sample.

  15. 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

  16. Assessing the arsenic-contaminated rice (Oryza sativa) associated children skin lesions.

    PubMed

    Liao, Chung-Min; Lin, Tzu-Ling; Hsieh, Nan-Hung; Chen, Wei-Yu

    2010-04-15

    The purpose of this study was to assess the potential risk of children skin lesions from arsenic-contaminated rice (Oryza sativa) consumption in West Bengal (India). Published age- and gender-specific skin lesions data in West Bengal were reanalyzed and incorporated into a Weibull dose-response model to predict children skin lesion prevalence. Monomethylarsonous acid (MMA(III)) levels in urine was used as a biomarker that could be predicted from a human physiologically based pharmacokinetic (PBPK) model. This study integrated arsenic contents in irrigation water, bioaccumulation factors of paddy soil, cooking methods, and arsenic bioavailability of cooked rice in gastrointestinal tract into a probabilistic risk model. Results indicated that children aged between 13 and 18 years might pose a relative higher potential risk of skin lesions to arsenic-contaminated cooked rice (odds ratios (ORs)=1.18 (95% CI 1.12-2.15)) than those of 1-6 years children (ORs=0.98 (0.85-1.40)). This study revealed the need to consider the relationships between cooking method and arsenic in cooked rice when assessing the risk associated with children skin lesions from rice consumption. This study suggested that arsenic-associated skin lesions risk from arsenic-contaminated rice consumption would be reduced significantly by adopting traditional rice cooking method (wash until clean; rice:water=1:6; discard excess water) as followed in West Bengal (India) and using water containing lower arsenic (e.g., <10 microg L(-1)) for cooking. PMID:19945215

  17. 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. PMID:21053954

  18. A Stochastic Approach To Human Health Risk Assessment Due To Groundwater Contamination

    NASA Astrophysics Data System (ADS)

    de Barros, F. P.; Rubin, Y.

    2006-12-01

    We present a probabilistic framework to addressing adverse human health effects due to groundwater contamination. One of the main challenges in health risk assessment is in relating it to subsurface data acquisition and to improvement in our understanding of human physiological responses to contamination. In this paper we propose to investigate this problem through an approach that integrates flow, transport and human health risk models with hydrogeological characterization. A human health risk cumulative distribution function is analytically developed to account for both uncertainty and variability in hydrogeological as well as human physiological parameters. With our proposed approach, we investigate under which conditions the reduction of uncertainties from flow physics, human physiology and exposure related parameters might contribute to a better understanding of human health risk assessment. Results indicate that the human health risk cumulative distribution function is sensitive to physiological parameters at low risk values associated with longer travel times. The results show that the worth of hydrogeological characterization in human health risk is dependent on the residence time of the contaminant plume in the aquifer and on the exposure duration of the population to certain chemicals.

  19. 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

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

    SciTech Connect

    Whelan, Gene ); McDonald, John P. ); Taira, Randal Y. ); Gnanapragasam, Emmanuel K.; Yu, Charley; Lew, Christine S.; Mills, William B.

    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 equal 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.

  1. Advances in molecular and "-omics" technologies to gauge microbial communities and bioremediation at xenobiotic/anthropogen contaminated sites.

    PubMed

    Desai, Chirayu; Pathak, Hilor; Madamwar, Datta

    2010-03-01

    Microbial bioremediation has been well-demonstrated as an ecofriendly and cost-competitive strategy for elimination of xenobiotic and or anthropogenic compounds from the polluted environments. However, successful execution of these versatile bioremediation strategies requires a thorough understanding of factors governing the growth, metabolism, dynamics and functions of indigenous microbial communities at contaminated sites. Recent innovative breakthroughs in genotypic profiling, ultrafast genome pyrosequencing, metagenomics, metatranscriptomics, metaproteomics and metabolomics along with bioinformatics tools have provided crucial in-sights of microbial communities and their mechanisms in bioremediation of environmental pollutants. Moreover, advances in these technologies have significantly improved the process of efficacy determination and implementation of microbial bioremediation strategies. The current review is focused on application of these molecular and "-omics" technologies in gauging the innate microbial community structures, dynamics and functions at contaminated sites or pollution containment facilities. PMID:19962886

  2. 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

  3. Assessment of heavy metal contamination in soils around Manali industrial area, Chennai, Southern India

    NASA Astrophysics Data System (ADS)

    Krishna, A. K.; Govil, P. K.

    2008-06-01

    The concentrations of heavy metals (As, Ba, Co, Cr, Cu, Ni, Mo, Pb, Sr, V and Zn) were studied in soils to understand metal contamination due to industrialization and urbanization around Manali industrial area in Chennai, Southern India. This area is affected by the industrial activity and saturated by industries like petrochemicals, refineries, and fertilizers generating hazardous wastes. The contamination of the soils was assessed on the basis of geoaccumulation index, enrichment factor (EF), contamination factor and degree of contamination. Soil samples were collected from the industrial area of Manali from the top 10-cm-layer of the soil. Soil samples were analyzed for heavy metals by using Philips MagiX PRO-2440 Wavelength dispersive X-ray fluorescence spectrometry. The data revealed elevated concentrations of Chromium (149.8-418.0 mg/kg), Copper (22.4-372.0 mg/kg), Nickel (11.8-78.8 mg/kg), Zinc (63.5-213.6 mg/kg) and Molybdenum (2.3-15.3 mg/kg). The concentrations of other elements were similar to the levels in the earth’s crust or pointed to metal depletion in the soil (EF < 1). The high-EFs for some heavy metals obtained in the soil samples show that there is a considerable heavy metal pollution, which could be correlated with the industries in the area. Contamination sites pose significant environmental hazards for terrestrial and aquatic ecosystems. They are important sources of pollution and may result in ecotoxicological effects on terrestrial, groundwater and aquatic ecosystems. In this perspective there is need for a safe dumping of waste disposal in order to minimize environmental pollution.

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

    SciTech Connect

    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

  5. Use of regulatory documents for assessing the contamination of soils with heavy metals

    NASA Astrophysics Data System (ADS)

    Nesterova, O. V.; Tregubova, V. G.; Semal, V. A.

    2014-11-01

    The chronological review and analysis of the existing regulatory documents relevant to the assessment of soil contamination with heavy metals have been presented. Attention has been given to the incorrect use of the term "total heavy metal content" and the method of its determination in a 5 M nitric acid solution recommended by some regulatory documents. The maximum permissible concentrations (MPCs) and tentatively permissible concentrations (TPCTPCs) for the total heavy metal contents are based on the above method; therefore, the conventional methods of determining the true total contents of heavy metals overestimate the degree of contamination. To avoid confusion, it has been proposed to call the content of a heavy metal in a 5 M nitric acid solution the "pseudototal" content and to compare the experimental results with the MPC or TPCTPC values only if the methods recommended by the regulatory documents were used.

  6. Assessment of fish health status in the Pechora River: effects of contamination.

    PubMed

    Lukin, A; Sharova, J; Belicheva, L; Camus, L

    2011-03-01

    The present study aimed to assess the ecological situation in the Pechora River Basin (east part of Sub-Arctic Russia) using histopathologies of fish and to relate fish health to environmental quality. This paper reports histopathological alterations of fish kidney, liver, and gills and their association with chemical contamination of the Pechora River. A variety of histopathological changes was found. Differences between studied species and sites of the Pechora River with regard to the type, prevalence, and severity of lesions were studied. The types of the lesions indicated that fish respond to both direct toxicant effects of contaminated water and sediment, and secondary stress effects caused by factors such as parasitism. The structural modifications found in this study are a result of acute damage associated with short-term exposure as much as chronic response due to long-term pollution. PMID:21040973

  7. Molecular characterization of microbial contaminants isolated from Umbilical Cord Blood Units for transplant.

    PubMed

    Bello-López, Juan Manuel; Noguerón-Silva, Jorge; Castañeda-Sánchez, Jorge Ismael; Rojo-Medina, Julieta

    2015-01-01

    Disposal of Umbilical Cord Blood Units due to microbial contamination is a major problem in Cord Blood Banks worldwide as it reduces the number of units available for transplantation. Additionally, economic losses are generated as result of resources and infrastructure used to obtain such units. Umbilical Cord Blood Units that showed initial microbial contamination were subject to strains isolation, identification, and characterization by sequencing the 16S rRNA gene and Enterobacterial Repetitive Intergenic Consensus (ERIC-PCR). Moreover, tests of antimicrobial resistance/sensitivity and phenotypic activities that may play an important role in microbial infection were performed. Microbial contamination was detected in 120 Umbilical Cord Blood Units (2.31%) in the period from 2003 to 2013. The most frequently isolated strains were Enterococcus faecium, followed by Staphylococcus epidermidis, Escherichia coli, Enterococcus faecalis, Staphylococcus haemoliticus, Klebsiella pneumoniae, Enterococcus durans, Lactobacillus helveticus, Enterococcus hiriae and Roseomonas genomospecies 5. The ERIC-PCR assays revealed a wide genetic diversity in some strains although belonging to the same genus and specie, indicating different sources of contamination. Broad-spectrum penicillins, third generation cephalosporins, aminoglycosides, and fluoroquinolones showed lower inhibitory activity on the tested strains. All strains were proteolytic, 67.69% were amylase-positive, 27.6% hemolysis-positive, and 34.71% nuclease-positive. The most common sources of contamination were: vaginal flora, digestive tract, and skin flora, highlighting the need for staff training in good manufacturing practices in collection SCU since all contaminants identified are part of the microbial flora of the donors. Implications and consequences in the therapeutic use of Umbilical Cord Blood Units for transplantation contaminated by multiresistant bacteria in immunocompromised patients are discussed. PMID

  8. Grading of soft tissue sarcomas: from histological to molecular assessment.

    PubMed

    Neuville, Agnes; Chibon, Frédéric; Coindre, Jean-Michel

    2014-02-01

    Several histological grading systems for soft tissue sarcomas have been described since the early 1980s. Their main objective is to select patients for adjuvant chemotherapy. Two histological grading systems are used in daily practice, the National Cancer Institute (NCI) and the French Federation of Cancer Centers Sarcoma Group (FNCLCC) systems. They have been devised by combining histological parameters: number of mitoses per high-power field, the presence of necrosis, cellular and nuclear morphology and the degree of cellularity for the NCI grading; and tumour differentiation, mitotic index and extent of necrosis for the French system. Histological grading is far more appropriate to assess the risk of metastasis. However, several limitations prevent its use: grade cannot be applied to all histological types, its reproducibility is not perfect, a three-grade system generates an intermediate grade with undetermined prognosis, and finally the core needle biopsy, now widely used for the diagnosis of soft tissue sarcoma, is not the best sample to assess the grade. The development of molecular grading in addition to histological grading probably represents the next step. Molecular signatures based on quantitative evaluation of chromosomal complexity such as CINSARC (complexity index in sarcomas) appear as a strong independent predictive factor for metastasis in several types of sarcoma, and even in several other types of cancer. When they can be instituted in daily practice on formalin fixed, paraffin embedded material, molecular signatures will not only provide information on risk of metastasis, but also better understanding of cancer development, response or resistance to evaluated drugs, and potential targets for future treatments. PMID:24378389

  9. 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. PMID:27073165

  10. Assessment of cadmium bioaccessibility to predict its bioavailability in contaminated soils.

    PubMed

    Li, Shi-Wei; Sun, Hong-Jie; Li, Hong-Bo; Luo, Jun; Ma, Lena Q

    2016-09-01

    In vitro assays have been developed to determine metal bioaccessibility in contaminated soils; however, their application to Cd is limited. To assess their suitability to determine Cd relative bioavailability (RBA), Cd-RBA in 12 contaminated soils containing 3.00-296mgkg(-1) Cd were determined using a mouse model and compared with Cd bioaccessibility data based on four assays including the UBM, SBRC, IVG, and PBET. After being administered feed amended with soil or CdCl2 for 10-day, the Cd concentrations in the mouse liver and/or kidneys were used as biomarkers to estimate Cd-RBA. Cd-RBA was comparable at 34-90% and 40-78% based on mouse liver and kidneys with RSD of 7.10-8.99%, and 37-84% based on mouse liver plus kidneys with lower RSD of 5.8%. Cadmium bioaccessibility in soils varied with assays, with 61-99, 59-103, 54-107, and 35-97% in the gastric phase and 20-56, 38-77, 42-88, and 19-64% in the intestinal phase of the UBM, SBRC, IVG and PBET assays. Based on the combined biomarker of liver plus kidneys, better correlation was observed for PBET (r(2)=0.61-0.70) than those for IVG, UBM and SBRC assays (0.12-0.52). The monthly Cd intake in children was 0.24-23.9μgkg(-1) using total Cd concentration in soils, which was reduced by 43% to 0.18-12.3μgkg(-1) using bioavailable Cd. Our data suggest it is important to consider Cd-RBA to assess risk associated with contaminated soils and the PBET may have potential to predict Cd-RBA in contaminated soils. PMID:27346741

  11. Assessing sediment connectivity to understand dynamics of contaminated sediment within coastal catchments of Fukushima Prefecture (Japan)

    NASA Astrophysics Data System (ADS)

    Chartin, Caroline; Evrard, Olivier; Onda, Yuichi; Ottlé, Catherine; Brossoni, Camille; Lefèvre, Irène; Lepage, Hugo; Bonté, Philippe; Patin, Jeremy; Ayrault, Sophie

    2013-04-01

    The Fukushima Dai-ichi Nuclear Power Plant accident has led to the release of large radionuclide quantities (e.g., about 20 PBq of Cs-137 and 200 PBq of I-131) into the atmosphere. About 80% of the release was blown out and over the Pacific Ocean. The remaining 20% of emissions were deposited as wet and dry deposits on soils of Fukushima Prefecture, mainly between 15-16 March. As most radionuclides are strongly sorbed by fine particles, they are likely to be redistributed within the landscape in association with soil and sediment particles transported by runoff and erosion processes. A spatial analysis of Ag-110m:Cs-137 ratio in soils and river sediments provided a way to trace those transfers. This fingerprinting study showed that particles eroded from inland mountain ranges exposed to the highest initial radionuclide fallout were already dispersed along coastal rivers, most likely during summer typhoons and spring snowmelt. Those results suggest that hillslopes and rivers have become a perennial source of radioactive contaminants to the Pacific Ocean off Fukushima Prefecture. This study aims to specify the location and nature of the preferential sources supplying contaminated material to the main rivers draining the Fukushima contamination plume. To this end, important parameters controlling soil erosion and sediment transfers within catchments, i.e. landscape morphology and land use characteristics, were preliminary derived from DEM data and satellite images for the River Mano, Nitta and Ota catchments (ca. 525 km²) draining the most radioactive part of the contamination plume that formed across Fukushima Prefecture. Then, those data were used to compute indices assessing the potential sediment connectivity (i) between hillslopes and rivers and (ii) between hillslopes and catchment outlets. Finally, spatially-distributed values of connectivity indices were confronted to gamma-emitting radionuclide activities (Cs-134, Cs-137 and Ag-110m) measured in riverbed

  12. Contamination of fish in UK fresh water systems: risk assessment for human consumption.

    PubMed

    Rose, Martin; Fernandes, Alwyn; Mortimer, David; Baskaran, Christina

    2015-03-01

    There is growing evidence that more people in the UK are consuming fish taken from inland waterways. This may be partly due to the increased numbers of migrants from Eastern Europe where this is part of traditional culture and partly because of a desire to try new foods encouraged by celebrity chefs. Fish can bioaccumulate environmental contaminants and so could contribute a significant amount to dietary exposure to these chemicals. This study examined the changing habits of anglers and consumers and characterised a range of existing and emerging contaminants in freshwater fish species with a view to determining current levels of occurrence and possible risk from consumption. The project was conducted in two stages. The first stage included (a) a study that identified freshwater systems that are contaminated either by anthropogenic activity or as a result of the geology of the area; and (b) socioeconomic research to assess the consumption habits of the public, particularly anglers, with respect to fish and shellfish from unmanaged inland waterways. Based on the outcome from the first stage, specific rivers and other inland waterways were chosen for investigation, along with the range of contaminants to be included in the analytical programme. Predicted contamination levels and prevalence of anglers were among the factors taken into consideration. The second stage of the project involved sampling and analysis of fish taken from selected locations on the chosen waterways. A range of fish species from a variety of inland water habitats were obtained. These were analysed for the following contaminants: heavy metals, chlorinated dioxins (PCDD/Fs), polybrominated biphenyls (PBBs), polychlorinated biphenyls (PCBs), brominated dioxins (PBDD/Fs), polychlorinated naphthalenes (PCNs), polybrominated diphenylethers (PBDEs), OC pesticides, organotin compounds and organo-fluorine compounds. Legal limits for contaminants apply only to food traded commercially, but some samples

  13. Baseline risk assessment of ground water contamination at the inactive uraniferous lignite ashing site near Bowman, North Dakota

    SciTech Connect

    Not Available

    1994-11-01

    This baseline risk assessment of ground water contamination at the inactive uraniferous lignite ashing site near Bowman, North Dakota, evaluates the potential impacts to public health or the environment from contaminated ground water at this site. This contamination is a result of the uraniferous lignite ashing process, when coal containing uranium was burned to produce uranium. Potential risk is quantified only for constituents introduced by the processing activities and not for the constituents naturally occurring in background ground water in the site vicinity. Background ground water, separate from any site-related contamination, imposes a percentage of the overall risk from ground water ingestion in the Bowman site vicinity. The US Department of Energy (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project is developing plans to address soil and ground water contamination at the site. The UMTRA Surface Project involves the determination of the extent of soil contamination and design of an engineered disposal cell for long-term storage of contaminated materials. The UMTRA Ground Water Project evaluates ground water contamination. Based on results from future site monitoring activities as defined in the site observational work plan and results from this risk assessment, the DOE will propose an approach for managing contaminated ground water at the Bowman site.

  14. 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

  15. 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

  16. In situ radiometric mapping as a proxy of sediment contamination: assessment of the underlying geochemical and -physical principles.

    PubMed

    van der Graaf, E R; Koomans, R L; Limburg, J; de Vries, K

    2007-05-01

    Correlations between sediment contaminants like heavy metals or organic micro-compounds and natural or anthropogenic radionuclides ((40)K, (238)U, (232)Th, (137)Cs) facilitates in situ mapping of the contaminated sediment using gamma-ray detectors. These maps can be made quickly and economically using surveys with towed underwater gamma-ray detectors and based on the fundamental correlation of contaminants with radioactivity. This paper aims at an assessment of the geochemical and -physical principles underlying these correlations. This assessment uses multivariate analysis of a data base containing information on radionuclides and contaminants for a large number of sediment samples used to derive radionuclide-contaminant correlations in radiometric mapping projects in freshwater bodies of the Netherlands. More specifically, the aims of this study are to test if these correlations are valid for the entire Dutch freshwater environment and to investigate the validity of the thesis that these correlations are mainly due to the presence of clay. PMID:17258466

  17. Baseline risk assessment of ground water contamination at the uranium mill tailings site Salt Lake City, Utah

    SciTech Connect

    Not Available

    1994-09-01

    This baseline risk assessment of groundwater contamination at the uranium mill tailings site near Salt Lake City, Utah, evaluates potential public health or environmental impacts resulting from ground water contamination at the former uranium ore processing site. The tailings and other contaminated material at this site were placed in a disposal cell located at Clive, Utah, in 1987 by the US Department of Energy`s Uranium Mill Tailings Remedial Action (UMTRA) Project. The second phase of the UMTRA Project is to evaluate residual ground water contamination at the former uranium processing site, known as the Vitro processing site. This risk assessment is the first site-specific document under the Ground Water Project. It will help determine the appropriate remedial action for contaminated ground water at the site.

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

    SciTech Connect

    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 followed 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)

  19. Shellfish and residual chemical contaminants: hazards, monitoring, and health risk assessment along French coasts.

    PubMed

    Guéguen, Marielle; Amiard, Jean-Claude; Arnich, Nathalie; Badot, Pierre-Marie; Claisse, Didier; Guérin, Thierry; Vernoux, Jean-Paul

    2011-01-01

    in similarly semi-enclosed waters elsewhere (bays, estuaries, and harbors).However, the mean concentrations of cadmium, mercury, lead, and benzo[a]pyrene,in transplanted mussels, were below the regulatory limits.In 2007, the mean daily consumption of shellfish in the general French population was estimated to be 4.5 g in adults; however, a wide variation occurs by region and season (INCA 2 study). Tabulated as a proportion of the diet, shellfish consumption represents only 0.16% of overall solid food intake. However, the INCA 2 survey was not well suited to estimating shellfish consumption because of the small number of shellfish consumers sampled. In contrast, the mean consumption rate of bivalve mollusks among adult high consumers of fish and seafood products, i.e., adults who eat fish or seafood at least twice a week, was estimated to be 153 g week-1 (8 kg yr-1). The highest mean consumption is for king scallops (39 g week-1), followed by oysters (34 g week-1) and mussels (22 g week-1). Thus, for high seafood consumers, the contribution of shellfish to inorganic contaminant levels is 1-10% TWI or PTWI for Cd, MeHg, and Sn (up to 19% for Sn), and the arsenic body burden is higher for 22% of individuals studied.The human health risks associated with consuming chemical contaminants in shellfish are difficult to assess for several reasons: effects may only surface after long-term exposure (chronic risk), exposures may be discontinuous, and contamination may derive from multiple sources (food, air, occupational exposure, etc.).Therefore, it is not possible to attribute a high body burden specifically to shellfish consumption even if seafood is a major dietary contributor of any contaminant, e.g.,arsenic and mercury.The data assembled in this review provide the arguments for maintaining the chemical contaminant monitoring programs for shellfish. Moreover, the results presented herein suggest that monitoring programs should be extended to other chemicals that are

  20. State of the art of contaminated site management in The Netherlands: policy framework and risk assessment tools.

    PubMed

    Swartjes, F A; Rutgers, M; Lijzen, J P A; Janssen, P J C M; Otte, P F; Wintersen, A; Brand, E; Posthuma, L

    2012-06-15

    This paper presents the policy framework of contaminated site management in The Netherlands and the corresponding risk assessment tools, including innovations that have taken place since an overview was published in 1999. According to the Dutch Soil Protection Act assessment framework, soils are subdivided into three quality classes: clean, slightly contaminated and seriously contaminated. Historic cases of slightly contaminated soils are managed in a sustainable way by re-use of soil material within a region on the basis of risk-based and land use specific Maximal Values and Background Values. In case of serious soil contamination remediation is in principle necessary and the urgency of remediation has to be determined based on site-specific risks for human health, the ecosystem and groundwater. The major risk assessment tools in The Netherlands are the CSOIL exposure model (human health risks and food safety), Species Sensitivity Distributions and the Soil Quality Triad (ecological risks), along with a procedure to assess the risks due to contaminant spreading to and in the groundwater. Following the principle 'simple if possible, complex when necessary', tiered approaches are used. Contaminated site practices are supported with web-based decision support systems. PMID:22578694

  1. Assessment of regional human health risks from lead contamination in Yunnan province, southwestern China.

    PubMed

    Lu, Lu; Cheng, Hongguang; Liu, Xuelian; Xie, Jing; Li, Qian; Zhou, Tan

    2015-01-01

    Identification and management the 'critical risk areas' where hotspot lead exposures are a potential risk to human health, become a major focus of public health efforts in China. But the knowledge of health risk assessment of lead pollution at regional and national scales is still limited in China. In this paper, under the guidance of 'sources-pathways-receptors' framework, regional human health risk assessment model for lead contamination was developed to calculate the population health risk in Yunnan province. And the cluster and AHP (analytic hierarchy process) analysis was taken to classify and calculate regional health risk and the decomposition of the regional health risk in the greatest health risk region, respectively. The results showed that Yunnan province can be divided into three areas. The highest health risk levels, located in northeastern Yunnan, including Kunming, Qujing, Zhaotong region. In those regions, lead is present at high levels in air, food, water and soil, and high population density which pose a high potential population risk to the public. The current study also reveals that most regional health risk was derived from the child receptors (age above 3 years) 4.3 times than the child receptors (age under 3 years), and ingestion of lead-contaminated rice was found to be the most significant contributor to the health risk (accounting for more than 49% health risk of total). This study can provide a framework for regional risk assessment in China and highlighted some indicators and uncertainties. PMID:25893826

  2. 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.

  3. Ecological assessment of a metal-contaminated pond in southern New England

    SciTech Connect

    Bleiler, J.A.; Fogg, A.; Reed, S.; Jop, K.; Putt, A.; George, C.

    1995-12-31

    An integrated ecological risk assessment was conducted to evaluate toxicity and bioaccumulation associated with sediment contamination in Plow Shop Pond (PSP), a 30-acre pond bordered by a landfill in central Massachusetts. Data from sediment and fish tissue analysis, as well as, results of sediments toxicity tests and a benthic community survey, were considered in the assessment. Arsenic, chromium, copper, lead, manganese, and mercury were found at elevated concentrations in PSP sediments. Fish tissue body weight appeared to be a good predictor of mercury contaminate burden in PSP, with heavier fish having higher concentrations of mercury. Macroinvertebrate community data suggested that PSP may be slightly impacted relative to a reference pond, with a significantly lower taxa richness and fewer pollution-intolerant species than the reference site. Despite the high levels of metals in PSP, only moderate levels of acute toxicity were observed in screening level sediment toxicity tests with Hyalella azteca, Chironomus tentans, and Ceriodaphnia dubia. Reduced growth and reproduction were observed in these tests, indicating potential sub-lethal effects in exposed to PSP sediments. It is likely that high levels of Acid Volatile Sulfides and Total Organic Carbon in PSP sediment have increased its metal-binding capacity, thus reducing bioavailability and toxicity of the inorganics in sediment. A dilution series Toxicity Identification Evaluation (TIE) was implemented to help identify stressors in PSP. The results of the integrated risk assessment at PSP are being used to evaluate remedial alternatives and to make risk management decisions.

  4. Assessment of Regional Human Health Risks from Lead Contamination in Yunnan Province, Southwestern China

    PubMed Central

    Lu, Lu; Cheng, Hongguang; Liu, Xuelian; Xie, Jing; Li, Qian; Zhou, Tan

    2015-01-01

    Identification and management the 'critical risk areas' where hotspot lead exposures are a potential risk to human health, become a major focus of public health efforts in China. But the knowledge of health risk assessment of lead pollution at regional and national scales is still limited in China. In this paper, under the guidance of 'sources-pathways-receptors' framework, regional human health risk assessment model for lead contamination was developed to calculate the population health risk in Yunnan province. And the cluster and AHP (analytic hierarchy process) analysis was taken to classify and calculate regional health risk and the decomposition of the regional health risk in the greatest health risk region, respectively. The results showed that Yunnan province can be divided into three areas. The highest health risk levels, located in northeastern Yunnan, including Kunming, Qujing, Zhaotong region. In those regions, lead is present at high levels in air, food, water and soil, and high population density which pose a high potential population risk to the public. The current study also reveals that most regional health risk was derived from the child receptors (age above 3 years) 4.3 times than the child receptors (age under 3years), and ingestion of lead-contaminated rice was found to be the most significant contributor to the health risk (accounting for more than 49 % health risk of total). This study can provide a framework for regional risk assessment in China and highlighted some indicators and uncertainties. PMID:25893826

  5. Probabilistic health risk assessment for ingestion of seafood farmed in arsenic contaminated groundwater in Taiwan.

    PubMed

    Liang, Ching-Ping; Jang, Cheng-Shin; Chen, Jui-Sheng; Wang, Sheng-Wei; Lee, Jin-Jing; Liu, Chen-Wuing

    2013-08-01

    Seafood farmed in arsenic (As)-contaminated areas is a major exposure pathway for the ingestion of inorganic As by individuals in the southwestern part of Taiwan. This study presents a probabilistic risk assessment using limited data for inorganic As intake through the consumption of the seafood by local residents in these areas. The As content and the consumption rate are both treated as probability distributions, taking into account the variability of the amount in the seafood and individual consumption habits. The Monte Carlo simulation technique is utilized to conduct an assessment of exposure due to the daily intake of inorganic As from As-contaminated seafood. Exposure is evaluated according to the provisional tolerable weekly intake (PTWI) established by the FAO/WHO and the target risk based on the US Environmental Protection Agency guidelines. The assessment results show that inorganic As intake from five types of fish (excluding mullet) and shellfish fall below the PTWI threshold values for the 95th percentiles, but exceed the target cancer risk of 10(-6). The predicted 95th percentile for inorganic As intake and lifetime cancer risks obtained in the study are both markedly higher than those obtained in previous studies in which the consumption rate of seafood considered is a deterministic value. This study demonstrates the importance of the individual variability of seafood consumption when evaluating a high exposure sub-group of the population who eat higher amounts of fish and shellfish than the average Taiwanese. PMID:23242940

  6. Groundwater contamination. Volume 2: Management, containment, risk assessment and legal issues

    SciTech Connect

    Rail, C.D.

    2000-07-01

    This book explains in a comprehensive way the sources for groundwater contamination, the regulations governing it, and the technologies for abating it. Volume 2 discusses aquifer management, including technologies to control and stabilize multiple influxes into the water table. This volume outlines strategies for stormwater control and groundwater restoration and presents numerous case histories of site analysis and remediation based on DOE and state documents. Among the many new features of this edition are a full discussion of risk assessment, the preparation of groundwater protection plans, and references linking the text to over 2,300 water-related Web sites.

  7. Assessment of groundwater contamination risk using hazard quantification, a modified DRASTIC model and groundwater value, Beijing Plain, China.

    PubMed

    Wang, Junjie; He, Jiangtao; Chen, Honghan

    2012-08-15

    Groundwater contamination risk assessment is an effective tool for groundwater management. Most existing risk assessment methods only consider the basic contamination process based upon evaluations of hazards and aquifer vulnerability. In view of groundwater exploitation potentiality, including the value of contamination-threatened groundwater could provide relatively objective and targeted results to aid in decision making. This study describes a groundwater contamination risk assessment method that integrates hazards, intrinsic vulnerability and groundwater value. The hazard harmfulness was evaluated by quantifying contaminant properties and infiltrating contaminant load, the intrinsic aquifer vulnerability was evaluated using a modified DRASTIC model and the groundwater value was evaluated based on groundwater quality and aquifer storage. Two groundwater contamination risk maps were produced by combining the above factors: a basic risk map and a value-weighted risk map. The basic risk map was produced by overlaying the hazard map and the intrinsic vulnerability map. The value-weighted risk map was produced by overlaying the basic risk map and the groundwater value map. Relevant validation was completed by contaminant distributions and site investigation. Using Beijing Plain, China, as an example, thematic maps of the three factors and the two risks were generated. The thematic maps suggested that landfills, gas stations and oil depots, and industrial areas were the most harmful potential contamination sources. The western and northern parts of the plain were the most vulnerable areas and had the highest groundwater value. Additionally, both the basic and value-weighted risk classes in the western and northern parts of the plain were the highest, indicating that these regions should deserve the priority of concern. Thematic maps should be updated regularly because of the dynamic characteristics of hazards. Subjectivity and validation means in assessing the

  8. 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. PMID:21277649

  9. Assessment of groundwater contamination from a hazardous dump site in Ranipet, Tamil Nadu, India

    NASA Astrophysics Data System (ADS)

    Rao, G. Tamma; Rao, V. V. S. Gurunadha; Ranganathan, K.; Surinaidu, L.; Mahesh, J.; Ramesh, G.

    2011-12-01

    Tanneries located in an industrial development area of Ranipet (India) manufactured chromate chemicals during 1976-1996. A large quantity of associated hazardous solid wastes has been stacked about 5-m high above ground level, spread over 3.5 ha inside one of the factory premises. The study area receives an average annual rainfall of 1,100 mm. The granitic formation in the northern part of Palar River catchment has high infiltration rates and has resulted in fast migration of the contamination to the water table. Chromium levels in the groundwater were found up to 275 mg/l. The available hydrogeological, geophysical and groundwater quality data bases have been used to construct a groundwater flow and mass transport model for assessing the groundwater contamination and it has been calibrated for the next 30 years. The migration has been found to be very slow, with a groundwater velocity of 10 m/year. This is the first field-scale study of its kind in this industrial area. The findings are of relevance to addressing the groundwater pollution due to indiscriminate disposal practices of hazardous waste in areas located on the phreatic aquifer. Further, it has been reported that the untreated effluent discharge adjacent to the chromium dump site is most influential in the migration of contaminants.

  10. Demilitarization of conventional ordnance: Priorities for data-base assessments of environmental contaminants

    SciTech Connect

    Layton, D.W.; McKone, T.E.; Hall, C.H.; Nelson, M.A.; Ricker, Y.E.

    1986-02-01

    The primary goal of this study has been to identify a set of environmental by-products from the demilitarization of conventional ordnance that should be the subject of more detailed data-base assessments. In order to rank the by-products according to their potential health risks, estimates were made of the contaminant releases associated with destructive techniques (e.g., open burning, open detonation, and incineration) and nondestructive techniques (e.g., filler recovery and reuse). Estimates of the types and quantities of propellants, explosives, and pyrotechnics in the demilitarization inventories of various installations in the US were made. To calculate hypothetical doses to man from contaminant releases, a multimedia compartmental model was used to calculate the concentrations of contaminants in water, soils, air, and biota. Based on an analysis of the doses and toxicity data for the compounds, several substances were recommended for further analysis, including DNT, TNT, and RDX and their degradation products in the environment. Other compounds are dibutyl phthalate, diphenylamine, HMX, and tetryl.

  11. 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

  12. 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

    2016-01-01

    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

  13. A preliminary assessment of the self-induced environment and contamination of the Space Telescope

    NASA Technical Reports Server (NTRS)

    Scialdone, J. J.

    1982-01-01

    Preliminary estimates for the internal pressures and surface contamination of the Space Telescope were made. The calculations for the transient pressures in the aft-shroud and telescope compartments considered two large communicating volumes that contain gaseous sources and sinks. The outgassing sources in the aft shroud consist of several scientific instruments, paints, insulations, and graphite-epoxy structures. With the exception of the instruments, these sources also exist in the telescope compartment. the outgassing functions were generated from ample test results at various temperatures and from internal pressure measurements in a vacuum test of one of the instruments. The venting occurs through combinations of series and parallel passages in both compartments. The calculated time constant of the two volumes and their respective passages, with the telescope protective door closed, is a few seconds, which is slightly less than that of the shuttle bay volume with the bay doors closed. With the telescope door closed, the pressures in the two compartments should decay to about 1OE-5 torr in about 200 hours. The contaminant deposits were assessed on the basis of expected partial pressures of the contaminant fraction of the outgassing. These pressures and the activation energies of the source materials were used to calculate the adsorbed and condensed deposits on the surfaces as a function of time.

  14. Assessment of stormwater impoundments as contaminant hazards to red-winged blackbirds

    SciTech Connect

    Eisemann, J.D.; Spading, D.

    1995-12-31

    Stormwater impoundments, a recent engineering solution to the treatment of stormwater, slow runoff and allow the settling of sediments and associated contaminants. They also provide valuable habitat in urban settings. In this study, the authors used red-winged blackbirds (Agelaius phoeniceus) to indicate potential contaminant hazards to avian species reared in stormwater impoundments. The authors studied four types of impoundments, grouped by the development in the supplying drainage; residential, commercial and highway development and a reference site with no development. They examined physiological biomarkers of 56, 8-day old nestlings, nesting parameters and foraging location of parent birds, food items delivered to nestlings, water chemistry, and sediments. Biomarker analysis included whole blood analysis for ALAD, blood serum chemistry (i.e., ALT, AST, CK, LDH, glucose, triglycerides, cholesterol, uric acid) and oxidative stress enzymes in liver tissue. Hepatic EROD and brain acetylcholinesterase levels were analyzed to assess exposure to contaminants other than metals. All samples were assayed for heavy metals by atomic absorption. A total of 198 nests were located. Overall nest success was significantly higher at the impoundment with no development in the supplying drainage. Focal parent feeding observations indicated females foraged less often in impoundments in highway locations. Preliminary analyses indicate sediments are not accumulating high metal levels. Serum and hepatic biomarker analyses indicate no statistically significant effects among drainage types.

  15. 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. PMID:26847833

  16. Assessing risk to human health from tropical leafy vegetables grown on contaminated urban soils.

    PubMed

    Nabulo, G; Young, S D; Black, C R

    2010-10-15

    Fifteen tropical leafy vegetable types were sampled from farmers' gardens situated on nine contaminated sites used to grow vegetables for commercial or subsistence consumption in and around Kampala City, Uganda. Trace metal concentrations in soils were highly variable and originated from irrigation with wastewater, effluent discharge from industry and dumping of solid waste. Metal concentrations in the edible shoots of vegetables also differed greatly between, and within, sites. Gynandropsis gynandra consistently accumulated the highest Cd, Pb and Cu concentrations, while Amaranthus dubius accumulated the highest Zn concentration. Cadmium uptake from soils with contrasting sources and severity of contamination was consistently lowest in Cucurbita maxima and Vigna unguiculata, suggesting these species were most able to restrict Cd uptake from contaminated soil. Concentrations of Pb and Cr were consistently greater in unwashed, than in washed, vegetables, in marked contrast to Cd, Ni and Zn. The risk to human health, expressed as a 'hazard quotient' (HQ(M)), was generally greatest for Cd, followed successively by Pb, Zn, Ni and Cu. Nevertheless, it was apparent that urban cultivation of leafy vegetables could be safely pursued on most sites, subject to site-specific assessment of soil metal burden, judicious choice of vegetable types and adoption of washing in clean water prior to cooking. PMID:20739044

  17. Phagocytosis in earthworms: An environmentally acceptable endpoint to assess immunotoxic potential of contaminated soils

    SciTech Connect

    Giggleman, M.A.; Fitzpatrick, L.C.; Goven, A.J.; Venables, B.J.; Callahan, C.A.

    1995-12-31

    Phagocytosis, a host-defense mechanism phylogenetically conserved throughout the animal kingdom, by earthworm (Lumbricus terrestris) coelomocytes has potential as a surrogate for vertebrates to be used as an environmentally acceptable endpoint to assess sublethal immunotoxic risks of contaminated soils to environmental (eg. higher wildlife) and public health. Coelomocytes can be exposed in vivo to complex contaminated parent soils by placing earthworms in situ at hazardous waste sites (HWS) or into soil samples and their dilutions with artificial soil (AS) in the laboratory, or in vitro to soil extracts and their fractionations. Here the authors report on phagocytosis by coelomocytes in earthworms exposed to pentachlorophenol (PCP) contaminated soils from a wood treatment HWS, PCP-spiked AS and PCP treated filter paper (FP). HWS soil was diluted to 25% with AS to a sublethal concentration (ca. 125 mg kg{sup {minus}1}) and earthworms exposed for 14d at 10 C under light conditions. AS was spiked at ca. 125 mg kg{sup {minus}1} PCP and earthworms were similarly exposed. Controls for both consisted of earthworms exposed to 100% AS. Earthworms were exposed to FP treated with a sublethal PCP concentration (15 {micro}g cm{sup {minus}2}) at 10 C under dark conditions for 96H. Controls were similarly exposed without PCP. Phagocytosis by coelomocytes in earthworms exposed to HWS soil, spiked AS and treated FP was suppressed 37, 41 and 29%, respectively. Results are discussed in terms of PCP body burdens and exposure protocols.

  18. 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. PMID:24839109

  19. MOLECULAR ANALYSIS OF MICROBIAL COMMUNITY STRUCTURES IN PRISTINE AND CONTAMINATED AQUIFERS: FIELD AND LABORATORY MICROCOSM EXPERIMENTS

    EPA Science Inventory

    This study used phylogenetic probes in hybridization analysis to (i) determine in situ microbial community structures in regions of a shallow sand aquifer that were oxygen depleted and fuel contaminated (FC) or aerobic and noncontaminted (NC) and (ii) examine alterations in micro...

  20. MIR Solar Array Return Experiment: Power Performance Measurements and Molecular Contamination Analysis Results

    NASA Technical Reports Server (NTRS)

    Visentine, James; Kinard, William; Brinker, David; Scheiman, David; Banks, Bruce; Albyn, Keith; Hornung, Steve; See, Thomas

    2001-01-01

    A solar array segment was recently removed from the Mir core module and returned for ground-based analysis. The segment, which is similar to the ones the Russians have provided for the FGB and Service Modules, was microscopically examined and disassembled by US and Russian science teams. Laboratory analyses have shown the segment to he heavily contaminated by an organic silicone coating, which was converted to an organic silicate film by reactions with atomic oxygen within the. orbital flight environment. The source of the contaminant was a silicone polymer used by the Russians as an adhesive and bonding agent during segment construction. During its life cycle, the array experienced a reduction in power performance from approx. 12%, when it was new and first deployed, to approx. 5%, when it was taken out of service. However, current-voltage measurements of three contaminated cells and three pristine, Russian standard cells have shown that very little degradation in solar array performance was due to the silicate contaminants on the solar cell surfaces. The primary sources of performance degradation is attributed to "thermal hot-spotting" or electrical arcing; orbital debris and micrometeoroid impacts; and possibly to the degradation of the solar cells and interconnects caused by radiation damage from high energy protons and electrons.

  1. Molecular Scale Determinants of Organic Contaminant and Pesticide Sorption by Clays

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Clay minerals and soil organic matter (SOM) are generally considered to be the most important soil components in the sorption of aqueous phase organic contaminants. During the past 25 years, much emphasis has been placed on the dominant role of SOM in sorption. However, there is increasing evidence...

  2. MOLECULAR TRACKING FECAL CONTAMINATION IN SURFACE WATERS: 16S RDNA VERSUS METAGENOMICS APPROACHES

    EPA Science Inventory

    Microbial source tracking methods need to be sensitive and exhibit temporal and geographic stability in order to provide meaningful data in field studies. The objective of this study was to use a combination of PCR-based methods to track cow fecal contamination in two watersheds....

  3. Long-term effects of dredging operations program: Assessing bioaccumulation in aquatic organisms exposed to contaminated sediments. Final report

    SciTech Connect

    Clarke, J.U.; McFarland, V.A.

    1991-07-01

    This paper synthesizes previous work on bioaccumulation to provide a working document for the environmental impact on the aquatic environment due to bioaccumulation of sediment contaminants resulting from dredging operations and dredged material placement. Emphasis is placed on explanation of basic concepts concerning, and factors influencing, sediment contaminant bioaccumulation and bioavailability. The paper presents several numerical methods for assessing bioaccumulation, including a simple method for estimating theoretical bioaccumulation potential (TBP) from sediment chemistry for neutral organic chemicals. Methods are also given for projecting contaminant concentrations in organism tissues when steady state is achieved, based on laboratory or field exposures to contaminated sediments. These assessments are presented in the context of the US Environmental Protection Agency's tiered testing approach for dredged material evaluation. The various numerical methods for bioaccumulation assessment are illustrated and compared using step-by-step example calculations with hypothetical and actual data.

  4. Molecular-Scale Characterization of Natural Organic Matter From A Uranium Contaminated Aquifer and its Utilization by Native Microbial Communities

    NASA Astrophysics Data System (ADS)

    Mouser, P. J.; Wilkins, M. J.; Williams, K. H.; Smith, D. F.; Paša-Tolić, L.

    2011-12-01

    The availability and form of natural organic matter (NOM) strongly influences rates of microbial metabolism and associated redox processes in subsurface environments. This is an important consideration in metal-contaminated aquifers, such as the DOE's Rifle Integrated Field Research Challenge (IFRC) site, where naturally occurring suboxic conditions in groundwater may play an important function in controlling uranium mobility, and therefore the long-term stewardship of the site. Currently, the biophysiochemical processes surrounding the nature of the aquifer and its role in controlling the fate and transport of uranium are poorly understood. Using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) with electrospray ionization (ESI), we characterized dissolved organic matter (DOM) chemistry for three surface and groundwater sources at Rifle and assessed microbial utilization in batch incubation experiments. FT-ICR-MS uniquely offers ultrahigh mass measurement accuracy and resolving power for polar organics, in addition to enabling elemental composition assignments of these compounds. Samples were collected from the Colorado River, a shallow groundwater aquifer adjacent to the river, and a spring/seep discharge point upgradient from the aquifer. DOM was concentrated and purified from each source and analyzed using FT-ICR-MS with ESI. We identified between 6,000 and 7,000 formulae at each location, with the river sample having the smallest and the spring sample having the largest number of identified peaks. The groundwater and spring samples contained DOM with a large percentage of formulae containing nitrogen and sulfur species, while the river sample was dominated by carbon, hydrogen, and oxygen species. Less than 38% of the formulae were shared between any two samples, indicating a significant level of uniqueness across the samples. Unsaturated hydrocarbons, cellulose, and lipids were rapidly utilized by indigenous bacteria during a 24-day

  5. Utilizing the great blue heron (Ardea herodias) in ecological risk assessments of bioaccumulative contaminants.

    PubMed

    Seston, Rita Marie; Zwiernik, Matthew John; Fredricks, Timothy Brian; Coefield, Sarah Jean; Tazelaar, Dustin Lee; Hamman, David Wayne; Paulson, John David; Giesy, John Paul

    2009-10-01

    Selection of an appropriate species is a key element of effective ecological risk assessments (ERA), especially when site-specific field studies are to be employed. Great blue herons (GBH) possess several ideal characteristics of a receptor species for the assessment of bioaccumulative compounds in the environment, such as ease of study, high potential for exposure, widespread distribution, and territorial foraging behavior. Methodologies for assessing exposure and population health are described herein. As outlined, the collection of GBH eggs, GBH nestling blood, and adult GBH blood allows for the determination of contaminant concentrations in various GBH tissues, a top-down assessment, which can be done in conjunction with predicted dietary exposure, a bottom-up assessment, to support a multiple lines of evidence approach. Additionally, population parameters, such as productivity and survival, can also be measured to elucidate if the contaminant exposure may be causing population level effects. Over the course of two years, three GBH rookeries were monitored for productivity and nestling exposure. Nests were monitored from blinds and individually accessed at multiple time points to obtain measures of nestling health, band nestlings, and collect eggs and nestling plasma. Multiple nests could frequently be accessed by climbing one tree, resulting in minimal effort to obtain the necessary sample size. Additionally, 51 adult GBH, captured in their foraging areas, were banded, and provided a blood sample. With these samples, a statistical difference in tissue based exposure was identified between the reference and target area. Statistically significant differences were also identified between the upper and lower reaches of the target area, thereby identifying a range of doses geographically which could be correlated to specific measurement endpoints. The ability to identify a dose response greatly increases the ability of the dataset to determine causation, a key goal

  6. 3H/3He age data in assessing the susceptibility of wells to contamination

    USGS Publications Warehouse

    Manning, A.H.; Solomon, D.K.; Thiros, S.A.

    2005-01-01

    Regulatory agencies are becoming increasingly interested in using young-ground water dating techniques, such as the 3H/3He method, in assessing the susceptibility of public supply wells (PSWs) to contamination. However, recent studies emphasize that ground water samples of mixed age may be the norm, particularly from long-screened PSWs, and tracer-based "apparent" ages can differ substantially from actual mean ages for mixed-age samples. We present age and contaminant data from PSWs in Salt Lake Valley, Utah, that demonstrate the utility of 3H and 3He measurements in evaluating well susceptibility, despite potential age mixing. Initial 3H concentrations (measured 3H + measured tritiogenic 3He) are compared to those expected based on the apparent 3H/3He age and the local precipitation 3H record. This comparison is used to determine the amount of modern water (recharged after ???1950) vs. prebomb water (recharged before ???1950) samples might contain. Concentrations of common contaminants were also measured using detection limits generally lower than those used for regulatory purposes. A clear correlation exists between the potential magnitude of the modern water fraction and both the occurrence and concentration of contaminants. For samples containing dominantly modern water based on their initial 3H concentrations, potential discrepancies between apparent 3H/ 3He ages and mean ages are explored using synthetic samples that are random mixtures of different modern waters. Apparent ages can exceed mean ages by up to 13 years for these samples, with an exponential age distribution resulting in the greatest discrepancies.

  7. Assessing the Public Health Impact and Effectiveness of Interventions To Prevent Salmonella Contamination of Sprouts.

    PubMed

    Ding, Hongliu; Fu, Tong-Jen

    2016-01-01

    Sprouts have been a recurring public health challenge due to microbiological contamination, and Salmonella has been the major cause of sprout-associated outbreaks. Although seed treatment and microbiological testing have been applied as risk reduction measures during sprout production, the extent to which their effectiveness in reducing the public health risks associated with sprouts has not been well investigated. We conducted a quantitative risk assessment to measure the risk posed by Salmonella contamination in sprouts and to determine whether and how mitigation strategies can achieve a satisfactory risk reduction based on the assumption that the risk reduction achieved by a microbiological sampling and testing program at a given sensitivity is equivalent to that achieved by direct inactivation of pathogens. Our results indicated that if the sprouts were produced without any risk interventions, the health impact caused by sprouts contaminated with Salmonella would be very high, with a median annual estimated loss of disability-adjusted life years (DALYs) of 691,412. Seed treatment (with 20,000 ppm of calcium hypochlorite) or microbiological sampling and testing of spent irrigation water (SIW) alone could reduce the median annual impact to 734 or 4,856 DALYs, respectively. Combining seed treatment with testing of the SIW would further decrease the risk to 58 DALYs. This number could be dramatically lowered to 3.99 DALYs if sprouts were produced under conditions that included treating seeds with 20,000 ppm of calcium hypochlorite plus microbiological testing of seeds, SIW, and finished products. Our analysis shows that the public health impact due to Salmonella contamination in sprouts could be controlled if seeds are treated to reduce pathogens and microbiological sampling and testing is implemented. Future advances in intervention strategies would be important to improve sprout safety further. PMID:26735027

  8. Baseline risk assessment for exposure to contaminants at the St. Louis Site, St. Louis, Missouri

    SciTech Connect

    Not Available

    1993-11-01

    The St. Louis Site comprises three noncontiguous areas in and near St. Louis, Missouri: the St. Louis Downtown Site (SLDS), the St. Louis Airport Storage Site (SLAPS), and the Latty Avenue Properties. The main site of the Latty Avenue Properties includes the Hazelwood Interim Storage Site (HISS) and the Futura Coatings property, which are located at 9200 Latty Avenue. Contamination at the St. Louis Site is the result of uranium processing and disposal activities that took place from the 1940s through the 1970s. Uranium processing took place at the SLDS from 1942 through 1957. From the 1940s through the 1960s, SLAPS was used as a storage area for residues from the manufacturing operations at SLDS. The materials stored at SLAPS were bought by Continental Mining and Milling Company of Chicago, Illinois, in 1966, and moved to the HISS/Futura Coatings property at 9200 Latty Avenue. Vicinity properties became contaminated as a result of transport and movement of the contaminated material among SLDS, SLAPS, and the 9200 Latty Avenue property. This contamination led to the SLAPS, HISS, and Futura Coatings properties being placed on the National Priorities List (NPL) of the US Environmental Protection Agency (EPA). The US Department of Energy (DOE) is responsible for cleanup activities at the St. Louis Site under its Formerly Utilized Sites Remedial Action Program (FUSRAP). The primary goal of FUSRAP is the elimination of potential hazards to human health and the environment at former Manhattan Engineer District/Atomic Energy Commission (MED/AEC) sites so that, to the extent possible, these properties can be released for use without restrictions. To determine and establish cleanup goals for the St. Louis Site, DOE is currently preparing a remedial investigation/feasibility study-environmental impact statement (RI/FS-EIS). This baseline risk assessment (BRA) is a component of the process; it addresses potential risk to human health and the environment associated wi

  9. Assessment of a Molecular Diffusion Model in MELCOR

    SciTech Connect

    Chang OH; Richard Moore

    2005-06-01

    The MELCOR (version 1.8.5) [1] computer code with INEEL revisions is being improved for the analysis of very high temperature gas-cooled reactors [2]. Following a loss-of-coolant accident, flow through the reactor vessel may initially stagnate due to a non-uniform concentration of helium and air. However, molecular diffusion will eventually result in a uniform concentration of air and helium. The differences in fluid temperatures within the reactor vessel will then result in the establishment of a natural circulation flow that can supply significant amounts of air to the reactor core. The heat released by the resulting oxidation of graphite in the reactor core has the potential to increase the peak fuel temperature. In order to analyze the effects of oxidation on the response of the reactor during accidents, a molecular diffusion model was added to MELCOR. The model is based on Fick's Second Law for spatially uniform pressure and temperature. This paper describes equimolal counter diffusion experiments in a two bulb diffusion cell and the results of the assessment calculations.

  10. 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...

  11. Baseline risk assessment of ground water contamination at the uranium mill tailings site near Lakeview, Oregon. Revision 1

    SciTech Connect

    1995-12-01

    Surface cleanup at the Uranium Mill Tailings Remedial Action (UMTRA) Project site near Lakeview, Oregon was completed in 1989. The Ground Water Project evaluates the nature and extent of ground water contamination that resulted from the uranium ore processing activities. The Ground Water Project is in its beginning stages. Human health may be at risk from exposure to ground water contaminated by uranium ore processing. Exposure could occur by drinking water pumped out of a hypothetical well drilled in the contaminated areas. Ecological risks to plants or animals may result from exposure to surface water and sediment that have received contaminated ground water. A risk assessment describes a source of contamination, how that contamination reaches people and the environment, the amount of contamination to which people or the ecological environment may be exposed, and the health or ecological effects that could result from that exposure. This risk assessment is a site-specific document that will be used to evaluate current and potential future impacts to the public and the environment from exposure to contaminated ground water. The results of this evaluation and further site characterization will determine whether any action is needed to protect human health or the ecological environment.

  12. Technical and operational assessment of molecular nanotechnology for space operations

    NASA Astrophysics Data System (ADS)

    McKendree, Thomas Lawrence

    2001-07-01

    This study assesses the performance of conventional technology and three levels of molecular nanotechnology (MNT) for space operations. The measures of effectiveness are technical performance parameters for five space transportation architectures, and the total logistics cost for an evaluation scenario with mining, market and factory locations on the Moon, Mars and asteroids. On these measures of effectiveness, improvements of 2--4 orders of magnitude are seen in chemical rockets, solar electric ion engines, solar sail accelerations (but not transit times), and in structural masses for planetary skyhooks and towers. Improvements in tether performance and logistics costs are nearer to 1 order of magnitude. Appendices suggest additional improvements may be possible in space mining, closed-environment life support, flexible operations, and with other space transportation architectures. In order to assess logistics cost, this research extends the facility location problem of location theory to orbital space. This extension supports optimal siting of a single facility serving circular, coplanar orbits, locations in elliptic planetary and moon orbits, and heuristic siting of multiple facilities. It focuses on conventional rocket transportation, and on high performance rockets supplying at least 1 m/s2 acceleration and 500,000 m/s exhaust velocity. Mathematica implementations are provided in appendices. Simple MNT allows diamond and buckytube construction. The main benefits are in chemical rocket performance, solar panel specific power, solar electric ion engine performance, and skyhook and tower structural masses. Complex MNT allows very small machinery, permitting large increases in solar panel specific power, which enables solar electric ion engines that are high performance rockets, and thus reduces total logistics costs an order of magnitude. Most Advance MNT allows molecular manufacturing, which enables self-repair, provides at least marginal improvements in nearly

  13. Baseline risk assessment of ground water contamination at the Monument Valley uranium mill tailings site Cane Valley, Arizona

    SciTech Connect

    1996-03-01

    The U.S. Department of Energy (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project consists of the Surface Project (Phase I) and the Ground Water Project (Phase II). Under the UMTRA Surface Project, tailings, radioactive contaminated soil, equipment, and materials associated with the former uranium ore processing at UMTRA Project sites are placed into disposal cells. The cells are designed to reduce radon and other radiation emissions and to minimize further contamination of ground water. Surface cleanup at the Monument Valley UMTRA Project site near Cane Valley, Arizona, was completed in 1994. The Ground Water Project evaluates the nature and extent of ground water contamination that resulted from the uranium ore processing activities. The Ground Water Project is in its beginning stages. Human health may be at risk from exposure to ground water contaminated by uranium ore processing. Exposure could occur by drinking water pumped out of a hypothetical well drilled in the contaminated areas. Adverse ecological and agricultural effects may also result from exposure to contaminated ground water. For example, livestock should not be watered with contaminated ground water. A risk assessment describes a source of contamination, how that contamination reaches people and the environment, the amount of contamination to which people or the ecological environment may be exposed, and the health or ecological effects that could result from that exposure. This risk assessment is a site-specific document that will be used to evaluate current and potential future impacts to the public and the environment from exposure to contaminated ground water. The results of this evaluation and further site investigations will be used to determine a compliance strategy to comply with the UMTRA ground water standards.

  14. Molecular characterisation of species and genotypes of Cryptosporidium and Giardia and assessment of zoonotic transmission

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The molecular characterization of species and genotypes of Cryptosporidium and Giardia is essential for accurately identifying organisms and assessing zoonotic transmission. Results of recent molecular epidemiologic studies strongly suggest that zoonotic transmission plays an important role in crypt...

  15. Molecular environmental science : an assessment of research accomplishments, available synchrotron radiation facilities, and needs.

    SciTech Connect

    Brown, G. E., Jr.; Sutton, S. R.; Bargar, J. R.; Shuh, D. K.; Fenter, P. A.; Kemner, K. M.

    2004-10-20

    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 pollutants 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 with

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

    SciTech Connect

    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 pollutants 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 with

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

    PubMed

    Preston, Todd M; Chesley-Preston, Tara L

    2015-03-01

    Contamination to aquatic resources from co-produced water (brine) associated with energy development has been documented in the northeastern portion of the Williston Basin; an area mantled by glacial drift. The presence and magnitude of brine contamination can be determined using the contamination index (CI) value from water samples. Recently, the U.S. Geological Survey published a section (~2.59 km(2)) level risk assessment of brine contamination to aquatic resources for Sheridan County, Montana, using oilfield and hydrogeological parameters. 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 (R(2)=0.65) outperformed the SCA (R(2)=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 (R(2)=0.62) versus all samples (R(2)=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. PMID:25468531

  18. Multi-criteria decision analysis with probabilistic risk assessment for the management of contaminated ground water

    SciTech Connect

    Khadam, Ibrahim M.; Kaluarachchi, Jagath J

    2003-10-01

    Traditionally, environmental decision analysis in subsurface contamination scenarios is performed using cost-benefit analysis. In this paper, we discuss some of the limitations associated with cost-benefit analysis, especially its definition of risk, its definition of cost of risk, and its poor ability to communicate risk-related information. This paper presents an integrated approach for management of contaminated ground water resources using health risk assessment and economic analysis through a multi-criteria decision analysis framework. The methodology introduces several important concepts and definitions in decision analysis related to subsurface contamination. These are the trade-off between population risk and individual risk, the trade-off between the residual risk and the cost of risk reduction, and cost-effectiveness as a justification for remediation. The proposed decision analysis framework integrates probabilistic health risk assessment into a comprehensive, yet simple, cost-based multi-criteria decision analysis framework. The methodology focuses on developing decision criteria that provide insight into the common questions of the decision-maker that involve a number of remedial alternatives. The paper then explores three potential approaches for alternative ranking, a structured explicit decision analysis, a heuristic approach of importance of the order of criteria, and a fuzzy logic approach based on fuzzy dominance and similarity analysis. Using formal alternative ranking procedures, the methodology seeks to present a structured decision analysis framework that can be applied consistently across many different and complex remediation settings. A simple numerical example is presented to demonstrate the proposed methodology. The results showed the importance of using an integrated approach for decision-making considering both costs and risks. Future work should focus on the application of the methodology to a variety of complex field conditions to

  19. Impact Assessment of Existing Vadose Zone Contamination at the Hanford Site SX Tank Farm

    SciTech Connect

    Khaleel, Raziuddin; White, Mark D.; Oostrom, Martinus; Wood, Marcus I.; Mann, Frederick M.; Kristofzski, John G.

    2007-11-01

    The USDOE has initiated an impact assessment of existing vadose zone contamination at the Hanford Site SX tank farm in southeastern Washington State. The assessment followed the Resource Conservation and Recovery Act (RCRA) Corrective Action process to address the impacts of past tank waste releases to the vadose zone at the single-shell tank farm. Numerical models were developed that consider the extent of contamination presently within the vadose zone and predict contaminant movement through the vadose zone to groundwater. The transport of representative mobile (technetium-99) and immobile (cesium-137) constituents was evaluated in modeling. The model considered the accelerated movement of moisture around and beneath single-shell tanks that is attributed to bare, gravel surfaces resulting from the construction of the underground storage tanks. Infiltration, possibly nearing 100 mm yr–1, is further amplified in the tank farm because of the umbrella effect created by percolating moisture being diverted by the impermeable, sloping surface of the large, 24-m-diameter, buried tank domes. For both the base case (no-action alternative) simulation and a simulation that considered placement of an interim surface barrier to minimize infiltration, predicted groundwater concentrations for technetium-99 at the SX tank farm boundary were exceedingly high, on the order of 106 pCi L–1. The predicted concentrations are, however, somewhat conservative because of our use of two-dimensional modeling for a three-dimensional problem. A series of simulations were performed, using recharge rates of 50, 30, and 10 mm yr–1, and compared to the base case (100 mm yr–1) results. As expected, lowering meteoric recharge delayed peak arrival times and reduced peak concentrations at the tank farm boundary.

  20. IMPACT ASSESSMENT OF EXISTING VADOSE ZONE CONTAMINATION AT THE HANFORD SITE SX TANK FARM

    SciTech Connect

    KHALEEL R

    2007-11-01

    The USDOE has initiated an impact assessment of existing vadose zone contamination at the Hanford Site SX tank farm in southeastern Washington State. The assessment followed the Resource Conservation and Recovery Act (RCRA) Corrective Action process to address the impacts of past tank waste releases to the vadose zone at the single-shell tank farm. Numerical models were developed that consider the extent of contamination presently within the vadose zone and predict contaminant movement through the vadose zone to groundwater. The transport of representative mobile (technetium-99) and immobile (cesium-137) constituents was evaluated in modeling. The model considered the accelerated movement of moisture around and beneath single-shell tanks that is attributed to bare, gravel surfaces resulting from the construction of the underground storage tanks. Infiltration, possibly nearing 100 mm yr{sup -1}, is further amplified in the tank farm because of the umbrella effect created by percolating moisture being diverted by the impermeable, sloping surface of the large, 24-m-diameter, buried tank domes. For both the base case (no-action alternative) simulation and a simulation that considered placement of an interim surface barrier to minimize infiltration, predicted, groundwater concentrations for technetium-99 at the SX tank farm boundary were exceedingly high, on the order of 10{sup 6} pCi L{sup -1}. The predicted concentrations are, however, somewhat conservative because of our use of two-dimensional modeling for a three-dimensional problem. A series of simulations were performed, using recharge rates of 50, 30, and 10 mm yr{sup -1}, and compared to the basecase(100 mm yr{sup -1}) results. As expected, lowering meteoric recharge delayed peak arrival times and reduced peak concentrations at the tank farm boundary.

  1. Preliminary assessment of contaminants in the sediment and organisms of the Swartkops Estuary, South Africa.

    PubMed

    Nel, L; Strydom, N A; Bouwman, H

    2015-12-30

    Urban estuaries are susceptible to metal and organic pollution, yet most remain understudied in South Africa with respect to the presence, concentrations and distribution of contaminants. Metal and organic chemical concentrations were assessed in sediment and organisms from different trophic levels in the lower reaches of the Swartkops Estuary. Species sampled included Upogebia africana (Malacostraca: Upogebiidae), Gilchristella aestuaria (Clupeidae), Psammogobius knysnaensis (Gobiidae), Mugil cephalus (Mugilidae), Lichia amia (Carangidae), Argyrosomus japonicus (Sciaenidae), Pomadasys commersonnii (Haemulidae) and Larus dominicanus (Avis: Laridae). This study is one of the most comprehensive studies to date assessing pollution levels in a food web in estuaries in South Africa. Due to biomagnification, higher concentrations of Arsenic, Lead, Mercury and Cadmium were found in the juveniles stages of popular angling fishes. High concentrations of Cadmium and Arsenic were recorded in the liver of L. amia, A. japonicus and P. commersonnii which exceed international quality food guidelines. Eggs from the gull, L. dominicanus, showed detectable concentrations of PCBs. PMID:26593278

  2. Contaminant exposure in Montrealers of Asian origin fishing the St. Lawrence River: Exploratory assessment

    SciTech Connect

    Kosatsky, T.; Przybysz, R.; Shatenstein, B.; Weber, J.P.; Armstrong, B.

    1999-02-01

    Fishing and fish consumption are widely practiced among members of certain ethnocultural groups. Information assessment led them to ascribe high levels of consumption of locally caught sportfish to Montrealers of Asian origin and to hypothesize that their choices of species and fish organs differ from those of the majority group. An exploratory assessment of contaminant bioindicators reflective of St. Lawrence river fish consumption was conducted in late 1995 among nine Vietnamese and nine Bangladeshi Montreal sportfishers identified by community contacts. Vietnamese participants, six men and three women, were 27--70 years of age and had immigrated to Canada 3--20 years earlier. In contrast, the nine Bangladeshi males aged 28--41 years had been in Canada for 2--13 years. Bioindicator concentrations among Bangladeshi and Vietnamese participants are compared to those found for majority-community Montreal-area high-level consumers recruited on the St. Lawrence River during winter 1995.

  3. 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.

  4. Site contamination health risk assessment case study involving tenant relocation from a former gasworks site.

    PubMed

    Turczynowicz, Len; Fitzgerald, D James; Nitschke, Monika; Mangas, Sam; McLean, Angela

    2007-10-01

    An Adelaide suburban public-housing residential site with 16 apartments was investigated after complaints of odor in some yard areas. A distinct 0.5-m layer of dark, odorous (tarry), contaminant material, which in some areas had been covered with plastic sheeting, was subsequently found beneath the topsoil across most of the site. This material appeared to extend beneath the apartments. Analysis indicated high levels of cyanide and polycyclic aromatic hydrocarbons (PAHs), consistent with gasworks waste. Historical investigation revealed that the site was originally owned by a gas company and that a large gasometer (gas-storage tank) existed in one corner of the site. This finding of significant soil contamination precipitated a decision by the health and housing authorities to notify tenants immediately and to plan for their relocation. In addition to tending to the consequent personal disruption and logistical difficulties this posed, a detailed risk assessment process was developed. Urine samples were collected before and after relocation and analyzed for 1-hydroxypyrene (1-OHP), a biomarker for polycyclic aromatic hydrocarbon (PAH) exposure. In addition, samples of tap water, indoor and outdoor air, indoor and ceiling dust, carpets, and soil from tillage areas were analyzed for PAHs. Data indicated a low health risk associated with tenancy on the site. This report presents details of the health risk assessment process undertaken and discusses vindicative reasons for tenant relocation. PMID:17763082

  5. Use of a {sup 15}N isotope dilution method to assess contaminant effects on soil nitrification

    SciTech Connect

    Nason, G.E.; Dinwoodie, G.D.

    1995-12-31

    Ecologically relevant bioassays are needed to assess effects of contaminants on soil processes such as decomposition and nutrient cycling. This study was conducted to assess the potential of a soil-based nitrification bioassay. Soil samples adjusted to 0.03 MPa moisture content were amended with 0.1, 1.0, 10 and 100 mg kg{sup {minus}1} PCP or PCB, and 0.05, 0.5, 5 and 50 mg kg{sup {minus}1} Hg and preincubated for 7 days. A 2-d incubation was then started by addition of 10 mg kg{sup {minus}1} {sup 15}NO{sub 3}-N. Diethyl ether used as a carrier for PCP addition had little effect on inorganic nitrogen concentrations during the incubation. Net nitrogen mineralization and nitrification were unaffected by PCB. Higher amendment levels of both PCP and Hg resulted in increases in ammonium concentrations and decreases in net nitrification. {sup 15}N-nitrate pool dilution was sensitive to contamination and showed some gross nitrification was occurring even when net nitrification had ceased. Recoveries of Hg and PCB at the end of the study were greater than 90%. Recovery of PCP was 5%. Incubations carried out under sterile and non-sterile conditions indicated that both sorption and biological degradation were factors in the low PCP recovery.

  6. Accumulation of Heavy Metals in Vegetable Species Planted in Contaminated Soils and the Health Risk Assessment

    PubMed Central

    Zhou, Hang; Yang, Wen-Tao; Zhou, Xin; Liu, Li; Gu, Jiao-Feng; Wang, Wen-Lei; Zou, Jia-Ling; Tian, Tao; Peng, Pei-Qin; Liao, Bo-Han

    2016-01-01

    The objectives of the present study were to investigate heavy metal accumulation in 22 vegetable species and to assess the human health risks of vegetable consumption. Six vegetable types were cultivated on farmland contaminated with heavy metals (Pb, Cd, Cu, Zn, and As). The target hazard quotient (THQ) method was used to assess the human health risks posed by heavy metals through vegetable consumption. Clear differences were found in the concentrations of heavy metals in edible parts of the different vegetables. The concentrations of heavy metals decreased in the sequence as leafy vegetables > stalk vegetables/root vegetables/solanaceous vegetables > legume vegetables/melon vegetables. The ability of leafy vegetables to uptake and accumulate heavy metals was the highest, and that of melon vegetables was the lowest. This indicated that the low accumulators (melon vegetables) were suitable for being planted on contaminated soil, while the high accumulators (leafy vegetables) were unsuitable. In Shizhuyuan area, China, the total THQ values of adults and children through consumption of vegetables were 4.12 and 5.41, respectively, suggesting that the residents may be facing health risks due to vegetable consumption, and that children were vulnerable to the adverse effects of heavy metal ingestion. PMID:26959043

  7. Trace organic contamination in biota collected from the Pearl River Estuary, China: a preliminary risk assessment.

    PubMed

    Wei, S; Lau, R K F; Fung, C N; Zheng, G J; Lam, J C W; Connell, D W; Fang, Z; Richardson, B J; Lam, P K S

    2006-12-01

    The marine ecosystem of the Pearl River Delta, located on the southern coast of China, has been heavily exploited following the rapid economic growth that has occurred since the 1980s. This investigation aimed to elucidate trace organic contamination in marine biota inhabiting the Pearl River Delta area. Biota samples, including green-lipped mussels (Perna viridis), oysters (Crassostrea rivularis) and shrimp (Penaeus orientalis) were sampled from 16 stations fringing the Estuary. Elevated concentrations (on a dry weight basis) of polycyclic aromatic hydrocarbons (27.8-1041.0 ng/g), petroleum hydrocarbons (1.7-2345.4 microg/g), polychlorinated biphenyls (2.1-108.8 ng/g), DDTs (1.9-79.0 ng/g), and hexachlorocyclohexanes (n.d.-38.4 ng/g) were recorded. A human health risk assessment was conducted to estimate the risk to local residents associated with the consumption of biota collected from the Pearl River Estuary. The results indicated that PCBs were at levels that may cause deleterious health effects in populations that consume large amounts of seafood. However, it would be instructive to establish health criteria for trace organic contaminants that are specific to the local populations, in order to derive a more accurate and relevant health risk assessment. PMID:16908034

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

    PubMed

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

    2013-03-01

    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 K(OW) 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. PMID:23258773

  9. 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

  10. Applying GORE-TEX technology for rapid contaminant assessments at Fort Gordon, Georgia

    USGS Publications Warehouse

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

    2010-01-01

    The U.S. Geological Survey, in cooperation with the U.S. Department of the Army at Fort Gordon, Georgia, deployed GORE1 adsorbent samplers along creeks and floodplains to rapidly assess potential contamination at abandoned facilities and in adjacent surface water. The samplers provide screening-level data to determine the presence or absence of volatile organic compounds, semi-volatile organic compounds, and polycyclic aromatic hydrocarbons and were deployed in saturated creek and floodplain sediments adjacent to four abandoned waste-disposal/warfare-training sites. Fuelrelated compounds, not solvents, are the most prevalent organic compounds detected along segments of McCoys Creek adjacent to the 19th Street landfill; South Prong Creek adjacent to the South Prong Creek waste-disposal area; an unnamed tributary to Butler Creek adjacent to the old hospital landfill; and the Brier Creek floodplain adjacent to the Patterson anti-tank range. All 37 samplers deployed in these assessments had detections of total petroleum hydrocarbons ranging from just above 3 (laboratory method detection level) to 344 micrograms per liter. Detections of octane that ranged from 1 to 7.6 micrograms per liter were common in all assessments, except for South Prong Creek. Calculated concentrations of benzene are at or just above the National Primary Drinking Water Standard maximum contaminant level for all samplers deployed in the floodplain at the Patterson anti-tank range. The highest calculated concentration of a specific fuel-related compound was for toluene collected at one sampling site on McCoys Creek adjacent to the 19th Street landfill, but the concentration was below the National Primary Drinking Water Standard. These results are being used by Fort Gordon environmental compliance personnel to decide if further assessments are needed at these abandoned waste-disposal/warfare-training sites

  11. A risk assessment tool for contaminated sites in low-permeability fractured media

    NASA Astrophysics Data System (ADS)

    Chambon, Julie C.; Binning, Philip J.; Jørgensen, Peter R.; Bjerg, Poul L.

    2011-06-01

    A risk assessment tool for contaminated sites in low-permeability fractured media is developed, based on simple transient and steady-state analytical solutions. The discrete fracture (DF) tool, which explicitly accounts for the transport along fractures, covers different source geometries and history (including secondary sources) and can be applied to a wide range of compounds. The tool successfully simulates published data from short duration column and field experiments. The use for risk assessment is illustrated by three typical risk assessment case studies, involving pesticides, chlorinated solvents, benzene and MTBE. The model is compared with field data and with results from a simpler approach based on an Equivalent Porous Media (EPM). Risk assessment conclusions of the DF and EPM approaches are very different due to the early breakthrough, long term tailing, and lower attenuation due to degradation associated with fractured media. While the DF tool simulates the field data, it is difficult to conclude that the DF model is superior to an EPM model because of a lack of long term monitoring data. However, better agreement with existing field data by the DF model using observed physical fracture parameters favors the use of this model over the EPM model for risk assessments.

  12. From Spill to Sequestration: The Molecular Journey of Contamination via Comprehensive Multiphase NMR.

    PubMed

    Masoom, Hussain; Courtier-Murias, Denis; Soong, Ronald; Maas, Werner E; Fey, Michael; Kumar, Rajeev; Monette, Martine; Stronks, Henry J; Simpson, Myrna J; Simpson, André J

    2015-12-15

    Comprehensive multiphase NMR is a novel NMR technique that permits all components (solutions, gels, and solids) to be studied in unaltered natural samples. In this study a wide range of CMP-NMR interaction and editing-based experiments are combined to follow contaminants (pentafluorophenol (PFP) and perfluorooctanoic acid (PFOA)) from the solution state (after a spill) through the gel-state and finally into the true solid-state (sequestered) in an intact water-swollen soil. Kinetics experiments monitoring each phase illustrate PFOA rapidly transfers from solution to the solid phase while for PFP the process is slower with longer residence times in the solution and gel phase. Interaction-based experiments reveal that PFOA enters the soil via its hydrophobic tails and selectively binds to soil microbial protein. PFP sorption shows less specificity exhibiting interactions with a range of gel and solid soil components with a preference toward aromatics (mainly lignin). The results indicate that in addition to more traditional measurements such as Koc, other factors including the influence of the contaminant on the soil-water interface, specific biological interactions, soil composition (content of lignin, protein, etc.) and physical accessibility/swellability of soil organic components will likely be central to better explaining and predicting the true behavior of contaminants in soil. PMID:26579583

  13. Widespread Environmental Contamination with Mycobacterium tuberculosis Complex Revealed by a Molecular Detection Protocol.

    PubMed

    Santos, Nuno; Santos, Catarina; Valente, Teresa; Gortázar, Christian; Almeida, Virgílio; Correia-Neves, Margarida

    2015-01-01

    Environmental contamination with Mycobacterium tuberculosis complex (MTC) has been considered crucial for bovine tuberculosis persistence in multi-host-pathogen systems. However, MTC contamination has been difficult to detect due to methodological issues. In an attempt to overcome this limitation we developed an improved protocol for the detection of MTC DNA. MTC DNA concentration was estimated by the Most Probable Number (MPN) method. Making use of this protocol we showed that MTC contamination is widespread in different types of environmental samples from the Iberian Peninsula, which supports indirect transmission as a contributing mechanism for the maintenance of bovine tuberculosis in this multi-host-pathogen system. The proportion of MTC DNA positive samples was higher in the bovine tuberculosis-infected than in presumed negative area (0.32 and 0.18, respectively). Detection varied with the type of environmental sample and was more frequent in sediment from dams and less frequent in water also from dams (0.22 and 0.05, respectively). The proportion of MTC-positive samples was significantly higher in spring (p<0.001), but MTC DNA concentration per sample was higher in autumn and lower in summer. The average MTC DNA concentration in positive samples was 0.82 MPN/g (CI95 0.70-0.98 MPN/g). We were further able to amplify a DNA sequence specific of Mycobacterium bovis/caprae in 4 environmental samples from the bTB-infected area. PMID:26561038

  14. Widespread Environmental Contamination with Mycobacterium tuberculosis Complex Revealed by a Molecular Detection Protocol

    PubMed Central

    Santos, Nuno; Santos, Catarina; Valente, Teresa; Gortázar, Christian; Almeida, Virgílio; Correia-Neves, Margarida

    2015-01-01

    Environmental contamination with Mycobacterium tuberculosis complex (MTC) has been considered crucial for bovine tuberculosis persistence in multi-host-pathogen systems. However, MTC contamination has been difficult to detect due to methodological issues. In an attempt to overcome this limitation we developed an improved protocol for the detection of MTC DNA. MTC DNA concentration was estimated by the Most Probable Number (MPN) method. Making use of this protocol we showed that MTC contamination is widespread in different types of environmental samples from the Iberian Peninsula, which supports indirect transmission as a contributing mechanism for the maintenance of bovine tuberculosis in this multi-host-pathogen system. The proportion of MTC DNA positive samples was higher in the bovine tuberculosis-infected than in presumed negative area (0.32 and 0.18, respectively). Detection varied with the type of environmental sample and was more frequent in sediment from dams and less frequent in water also from dams (0.22 and 0.05, respectively). The proportion of MTC-positive samples was significantly higher in spring (p<0.001), but MTC DNA concentration per sample was higher in autumn and lower in summer. The average MTC DNA concentration in positive samples was 0.82 MPN/g (CI95 0.70–0.98 MPN/g). We were further able to amplify a DNA sequence specific of Mycobacterium bovis/caprae in 4 environmental samples from the bTB-infected area. PMID:26561038

  15. Use of the aquatic oligochaete lumbriculus variegatus for assessing the toxicity and bioaccumulation of sediment-associated contaminants

    SciTech Connect

    Phipps, G.L.; Ankley, G.T.; Benoit, D.A.; Mattson, V.R. )

    1993-02-01

    In this paper the authors describe test methods utilizing the aquatic oligochaete Lumbriculus variegatus to assess the acute and chronic toxicity and the presence of bioaccumulatable compounds in contaminated sediments. Lumbriculus variegatus was chosen as a test species because (a) it represents an ecologically relevant component of freshwater ecosystems; (b) it is suitable for long-term testing and evaluation of chronic toxicity end points (e.g., growth, reproduction); (c) it is exposed via all important routes of concern, including ingesting of contaminated particles; and (d) it has sufficient biomass to assess bioaccumulation of contaminants. Also, Lumbriculus variegatus is easily cultured and handled. Described herein are culturing procedures and test protocols for Lumbriculus variegatus, as well as two examples of the types of experimental data generated when using the oligochaete in test with contaminated sediments. Two case studies are presented in which L. variegatus was used to assess the bioaccumulation of metals (cadmium, nickel) from contaminated sediments and assess the toxicity of sediment samples collected from the copper-contaminated Keweenaw Waterway system in Michigan.

  16. Quantitative assessment of hydrocarbon contamination in soil using reflectance spectroscopy: a "multipath" approach.

    PubMed

    Schwartz, Guy; Ben-Dor, Eyal; Eshel, Gil

    2013-11-01

    Petroleum hydrocarbons are contaminants of great significance. The commonly used analytic method for assessing total petroleum hydrocarbons (TPH) in soil samples is based on extraction with 1,1,2-Trichlorotrifluoroethane (Freon 113), a substance prohibited to use by the Environmental Protection Agency. During the past 20 years, a new quantitative methodology that uses the reflected radiation of solids has been widely adopted. By using this approach, the reflectance radiation across the visible, near infrared-shortwave infrared region (400-2500 nm) is modeled against constituents determined using traditional analytic chemistry methods and then used to predict unknown samples. This technology is environmentally friendly and permits rapid and cost-effective measurements of large numbers of samples. Thus, this method dramatically reduces chemical analytical costs and secondary pollution, enabling a new dimension of environmental monitoring. In this study we adapted this approach and developed effective steps in which hydrocarbon contamination in soils can be determined rapidly, accurately, and cost effectively solely from reflectance spectroscopy. Artificial contaminated samples were analyzed chemically and spectrally to form a database of five soils contaminated with three types of petroleum hydrocarbons (PHCs), creating 15 datasets of 48 samples each at contamination levels of 50-5000 wt% ppm (parts per million). A brute force preprocessing approach was used by combining eight different preprocessing techniques with all possible datasets, resulting in 120 different mutations for each dataset. The brute force was done based on an innovative computing system developed for this study. A new parameter for evaluating model performance scoring (MPS) is proposed based on a combination of several common statistical parameters. The effect of dividing the data into training validation and test sets on modeling accuracy is also discussed. The results of this study clearly show

  17. 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-...

  18. Baseline risk assessment of ground water contamination at the Uranium Mill Tailings Site near Lakeview, Oregon. Revision 2

    SciTech Connect

    1996-03-01

    The U.S. Department of Energy (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project consists of the Surface Project (Phase I) and the Ground Water Project (Phase II). Under the UMTRA Surface Project, tailings, contaminated soil, equipment, and materials associated with the former uranium ore processing at UMTRA Project sites are placed into disposal cells. The cells are designed to reduce radon and other radiation emissions and to minimize further contamination of ground water. Surface cleanup at the UMTRA Project site near Lakeview, Oregon, was completed in 1989. The mill operated from February 1958 to November 1960. The Ground Water Project evaluates the nature and extent of ground water contamination that resulted from the uranium ore processing activities. The Ground Water Project is in its beginning stages. Human health may be at risk from exposure to ground water contaminated by uranium ore processing. Exposure could occur by drinking water pumped out of a hypothetical well drilled in the contaminated areas. Ecological risks to plants or animals may result from exposure to surface water and sediment that have received contaminated ground water. A risk assessment describes a source of contamination, how that contamination reaches people and the environment, the amount of contamination to which people or the ecological environment may be exposed, and the health or ecological effects that could result from that exposure. This risk assessment is a site-specific document that will be used to evaluate current and potential future impacts to the public and the environment from exposure to contaminated ground water. The results of this evaluation and further site characterization will determine whether any action is needed to protect human health or the ecological environment.

  19. Baseline risk assessment of groundwater contamination at the uranium mill tailings site near Shiprock, New Mexico. Draft

    SciTech Connect

    Not Available

    1993-09-01

    This report evaluates potential impact to public health or the environment resulting from groundwater contamination at the former uranium mill processing site. The tailings and other contaminated material at this site were placed in a disposal cell on the site in 1986 by the US Department of Energy`s (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project. Currently, the UMTRA Project is evaluating groundwater contamination. This risk assessment is the first document specific to this site for the Groundwater Project. This risk assessment follows the approach outlined by the US Environmental Protection Agency (EPA). The first step is to evaluate groundwater data collected from monitor wells at the site. Evaluation of these data showed that the main contaminants in the floodplain groundwater are arsenic, magnesium, manganese, nitrate, sodium, sulfate, and uranium. The complete list of contaminants associated with the terrace groundwater could not be determined due to the lack of the background groundwater quality data. However, uranium, nitrate, and sulfate are evaluated since these chemicals are clearly associated with uranium processing and are highly elevated compared to regional waters. It also could not be determined if the groundwater occurring in the terrace is a usable water resource, since it appears to have originated largely from past milling operations. The next step in the risk assessment is to estimate how much of these contaminants people would be exposed to if a drinking well were installed in the contaminated groundwater or if there were exposure to surface expressions of contaminated water. Potential exposures to surface water include incidental contact with contaminated water or sediments by children playing on the floodplain and consumption of meat and milk from domestic animals grazed and watered on the floodplain.

  20. Baseline risk assessment of ground water contamination at the Monument Valley Uranium Mill Tailings Site, Cane Valley, Arizona. Revision 1

    SciTech Connect

    Not Available

    1994-08-01

    This baseline risk assessment evaluates potential impact to public health or the environment from ground water contamination at the former uranium mill processing site in Cane Valley near Monument Valley, Arizona. The US Department of Energy (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project has relocated and stabilized this site`s tailings and other contaminated material in a disposal cell at Mexican Hat, Utah. The second phase of the UMTRA Project is to evaluate ground water contamination. This risk assessment is the first document specific to this site for the Ground Water Project that evaluates potential health and environmental risks. It will help determine the approach required to address contaminated ground water at the site.

  1. Baseline risk assessment for groundwater contamination at the uranium mill tailings site near Monument Valley, Arizona. Draft

    SciTech Connect

    Not Available

    1993-09-01

    This baseline risk assessment evaluates potential impact to public health or the environment resulting from groundwater contamination at the former uranium mill processing site near Monument Valley, Arizona. The tailings and other contaminated material at this site are being relocated and stabilized in a disposal cell at Mexican Hat, Utah, through the US Department of Energy (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project. The tailings removal is planned for completion by spring 1994. After the tailings are removed, groundwater contamination at the site will continue to be evaluated. This risk assessment is the first document specific to this site for the Groundwater Project. It will be used to assist in determining what remedial action is needed for contaminated groundwater at the site.

  2. Baseline risk assessment of ground water contamination at the uranium mill tailings sites near Slick Rock, Colorado

    SciTech Connect

    Not Available

    1994-11-01

    This baseline risk assessment of ground water contamination at the uranium mill tailings sites near Slick Rock, Colorado, evaluates potential public health and environmental impacts resulting from ground water contamination at the former North Continent (NC) and Union Carbide (UC) uranium mill processing sites. The tailings at these sites will be placed in a disposal cell at the proposed Burro Canyon, Colorado, site. The US Department of Energy (DOE) anticipates the start of the first phase remedial action by the spring of 1995 under the direction of the DOE`s Uranium Mill Tailings Remedial Action (UMTRA) Project. The second phase of the UMTRA Project will evaluate ground water contamination. This baseline risk assessment is the first site-specific document for these sites under the Ground Water Project. It will help determine the compliance strategy for contaminated ground water at the site. In addition, surface water and sediment are qualitatively evaluated in this report.

  3. 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

  4. Assessment of plant uptake models used in exposure assessment tools for soils contaminated with organic pollutants.

    PubMed

    Takaki, Koki; Wade, Andrew J; Collins, Chris D

    2014-10-21

    The aim of this study was to evaluate and improve the accuracy of plant uptake models for neutral hydrophobic organic pollutants (1 < logK(OW) < 9, -8 < logK(AW) < 0) used in regulatory exposure assessment tools, using uncertainty and sensitivity analyses. The models considered were RAIDAR, EUSES, CSOIL, CLEA, and CalTOX. In this research, CSOIL demonstrated the best performance of all five exposure assessment tools for root uptake from polluted soil in comparison with observed data, but no model predicted shoot uptake well. Recalibration of the transpiration and volatilisation parameters improved the performance of CSOIL and CLEA. The dominant pathway for shoot uptake simulated differed according to the properties of the chemical under consideration; those with a higher air-water partition coefficient were transported into shoots via the soil-air-plant pathway, while chemicals with a lower octanol-water partition coefficient and air-water partition coefficient were transported via the root. The soil organic carbon content was a particularly sensitive parameter in each model and using a site specific value improved model performance. PMID:25203369

  5. Development of Triad approach based system for ecological risk assessment for contaminated areas of Kyrgyzstan

    NASA Astrophysics Data System (ADS)

    Kydralieva, Kamilia; Uzbekov, Beksultan; Khudaibergenova, Bermet; Terekhova, Vera; Jorobekova, Sharipa

    2014-05-01

    This research is aimed to develop a high-effective system of an ecological risk assessment and risk-based decision making for anthropogenic ecosystems, with particular focus on the soils of the Kyrgyz Republic. The study is focused on the integration of Triad data including chemical, biological and ecotoxicological soil markers to estimate the potential risk from soils of highly anthropized areas impacted by deposition of different pollutants from mining operation. We focus on technogenic areas of Kyrgyzstan, the former uranium-producing province. Triad-based ecological risk assessment for technogenic sites are not currently used in Kyrgyzstan. However, the vitality of such research is self-evident. There are about 50 tailing dumps and more than 80 tips of radioactive waste which are formed as a result of uranium and complex ores (mercury, antimony, lead, cadmium and etc) mining around the unfavorable aforementioned places. According to the Mining Wastes' Tailings and Fills Rehabilitation Centre established in 1999 by a special Government's Resolution, one of the most ecologically dangerous uranium tailings resides in Kadzhi-Say. Although uranium processing is no longer practiced in Kadzhi-Say, a large number of open landfills and uranium ore storages still remain abandoned at the vicinity of this settlement. These neglected sites have enormous problems associated with soil erosion known as "technogenic deserts". The upper soil horizons are deprived of humus and vegetation, which favor the formation of low-buffer landscapes in the zones of maximum contamination. As a result, most of these areas are not re-cultivated and remain in critical environmental condition (Bykovchenko, et al., 2005; Tukhvatshin, 2005; Suranova, 2006). Triad data for assessing environmental risk and biological vulnerability at contaminated sites will be integrated. The following Triad-based parameters will be employed: 1) chemical soil analyses (revealing the presence of potentially dangerous

  6. Characterization of the human kinetic adjustment factor for the health risk assessment of environmental contaminants.

    PubMed

    Valcke, Mathieu; Krishnan, Kannan

    2014-03-01

    A default uncertainty factor of 3.16 (√10) is applied to account for interindividual variability in toxicokinetics when performing non-cancer risk assessments. Using relevant human data for specific chemicals, as WHO/IPCS suggests, it is possible to evaluate, and replace when appropriate, this default factor by quantifying chemical-specific adjustment factors for interindividual variability in toxicokinetics (also referred to as the human kinetic adjustment factor, HKAF). The HKAF has been determined based on the distributions of pharmacokinetic parameters (e.g., half-life, area under the curve, maximum blood concentration) in relevant populations. This article focuses on the current state of knowledge of the use of physiologically based algorithms and models in characterizing the HKAF for environmental contaminants. The recent modeling efforts on the computation of HKAF as a function of the characteristics of the population, chemical and its mode of action (dose metrics), as well as exposure scenario of relevance to the assessment are reviewed here. The results of these studies, taken together, suggest the HKAF varies as a function of the sensitive subpopulation and dose metrics of interest, exposure conditions considered (route, duration, and intensity), metabolic pathways involved and theoretical model underlying its computation. The HKAF seldom exceeded the default value of 3.16, except in very young children (i.e., <≈ 3 months) and when the parent compound is the toxic moiety. Overall, from a public health perspective, the current state of knowledge generally suggest that the default uncertainty factor is sufficient to account for human variability in non-cancer risk assessments of environmental contaminants. PMID:24038072

  7. Assessment of macrobenthos response to sediment contamination in the San Francisco Estuary, California, USA.

    PubMed

    Thompson, Bruce; Lowe, Sarah

    2004-09-01

    A multimetric benthic assessment method was developed for two benthic assemblages in the San Francisco Estuary (USA) using data from several monitoring programs collected over five years. Assessment indicators used were total number of taxa, total abundances, oligochaete abundances, number of molluscan taxa, number of amphipod taxa, and Capitella capitata and Streblospio benedicti abundances. Exceedances of the maximum or minimum indicator values in reference samples were used to assess test samples using a weight-of-evidence to obtain an assessment value. Only 2.5% of the samples from the deeper, offshore sites had benthic impacts, 14.3% of the samples from near wastewater discharges had impacts, and 78.3% of the samples from the estuary margins and channels were impacted. Impacted samples from both assemblages had significantly higher mean effects range-median quotient values (mERMq) than reference samples, total organic carbon (TOC) was significantly higher in the impacted samples from the mesohaline assemblage, and percent fines was significantly higher in the impacted samples from the polyhaline assemblage, reflecting the close associations of contaminants with fine sediments and organic material. In samples with mERMq below 0.050, there were no benthic impacts. The incidence of impacts remained low (9.4%) at mERMq below 0.146, but when mERMq was above 0.146, 68.2% of the samples had benthic impacts, and samples with mERMq above 0.740 were always impacted. PMID:15378995

  8. 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

  9. Validating the use of biopsy sampling in contamination assessment studies of small cetaceans.

    PubMed

    Méndez-Fernandez, Paula; Galluzzi Polesi, Paola; Taniguchi, Satie; de O Santos, Marcos C; Montone, Rosalinda C

    2016-06-15

    Remote biopsy sampling is the most common technique for acquiring samples from free-ranging marine mammals. However, such techniques may result in variable sampling being sometimes superficial skin and blubber biopsies. For decades, blubber has been used to monitor the exposure of marine mammals to persistent organic pollutants (POPs), but little is known regarding the variability of POPs as a function of blubber depth in small cetaceans and the available literature offers variable results. Thus, the aim of the present study was to validate biopsy sampling for monitoring contaminant concentrations in small, free-ranging cetaceans. Samples from the dorsal blubber of 10 incidentally captured Atlantic spotted dolphins (Stenella frontalis) were separated into two different layers (outer and inner) to investigate the influence of sampling depth on POP concentrations. POP concentrations were compared to those of the full blubber layer. The results revealed no significant differences in lipid content between males and females or among the inner, outer and full blubber layers (p>0.05). Moreover, the wet and lipid weight concentrations of all POP classes analysed [i.e. polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethanes (DDTs), polybrominated diphenyl ethers (PBDEs), hexachlorobenzene (HCB), hexachlorocyclohexanes (HCHs), chlordanes (CHLs) and mirex] did not differ significantly with blubber depth (p>0.05). POP classes followed the same decreasing order of wet weight concentrations in blubber layers and full blubber: PCBs>DDTs>PBDEs>mirex>HCB>HCHs>CHLs. Moreover, there was a low degree of differentiation in the accumulation of POP congeners. The present findings indicated that the distribution of contaminants was homogenous with blubber depth, which validates the use of biopsy sampling for the assessment of contaminants in small cetaceans. PMID:27113024

  10. Designing the ideal model for assessment of wound contamination after gunshot injuries: a comparative experimental study

    PubMed Central

    2012-01-01

    Background Modern high-velocity projectiles produce temporary cavities and can thus cause extensive tissue destruction along the bullet path. It is still unclear whether gelatin blocks, which are used as a well-accepted tissue simulant, allow the effects of projectiles to be adequately investigated and how these effects are influenced by caliber size. Method Barium titanate particles were distributed throughout a test chamber for an assessment of wound contamination. We fired .22-caliber Magnum bullets first into gelatin blocks and then into porcine hind limbs placed behind the chamber. Two other types of bullets (.222-caliber bullets and 6.5 × 57 mm cartridges) were then shot into porcine hind limbs. Permanent and temporary wound cavities as well as the spatial distribution of barium titanate particles in relation to the bullet path were evaluated radiologically. Results A comparison of the gelatin blocks and hind limbs showed significant differences (p < 0.05) in the mean results for all parameters. There were significant differences between the bullets of different calibers in the depth to which barium titanate particles penetrated the porcine hind limbs. Almost no particles, however, were found at a penetration depth of 10 cm or more. By contrast, gas cavities were detected along the entire bullet path. Conclusion Gelatin is only of limited value for evaluating the path of high-velocity projectiles and the contamination of wounds by exogenous particles. There is a direct relationship between the presence of gas cavities in the tissue along the bullet path and caliber size. These cavities, however, are only mildly contaminated by exogenous particles. PMID:22490236

  11. 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. PMID:26495827

  12. Fumonisin contamination of food: progress in development of biomarkers to better assess human health risks.

    PubMed

    Turner, P C; Nikiema, P; Wild, C P

    1999-07-15

    Fumonisins, fungal toxins produced by Fusarium moniliforme, contaminate maize based foods and feeds throughout the world. They cause liver and kidney toxicity in animals in addition to leukoencephalomalacia in horses and pulmonary edema in pigs. Fumonisin B(1) is carcinogenic in rats and mice. Ecological studies have linked consumption of fumonisin contaminated maize with oesophageal cancer in human populations in South Africa and China. This review discusses the potential health risks for people exposed to the fumonisins, and describes how mechanistic studies of toxicity in animal models have allowed the development of putative biomarkers of fumonisin exposure at the individual level. The requirements for an applicable biomarker include sample availability as well as a high specificity and sensitivity for the exposure of interest. Most environmental toxic insults involve complex exposures both to other toxins and to infections; these confounding factors need to be considered in assessing both the validity of the biomarker and the exposure-disease associations. Fumonisins can be detected in the urine of animals in feeding studies but the sensitivity of the current methodology means only highly exposed people could be monitored. Mechanistic studies indicate that ceramide synthase, an enzyme involved in sphingolipid synthesis, is one cellular target for fumonisin toxicity and carcinogenicity, and this disruption to sphingolipid metabolism increases the ratio of two sphingoid precursors, sphinganine and sphingosine. The altered ratio has been observed in tissues, serum and urine for a number of animal models suggesting it as a good candidate marker of fumonisin exposure. Despite development of analytical methods to measure this biomarker there have been no studies to date correlating it to fumonisin intake in people. Given the toxic effects of fumonisins in animals and the widespread human exposure, which has been calculated to reach 440 micrograms kg(-1) body weight

  13. Evaluation and assessment of baseline metal contamination in surface sediments from the Bernam River, Malaysia.

    PubMed

    Kadhum, Safaa A; Ishak, Mohd Yusoff; Zulkifli, Syaizwan Zahmir

    2016-04-01

    The Bernam River is one of the most important rivers in Malaysia in that it provides water for industries and agriculture located along its banks. The present study was conducted to assess the level of contamination of heavy metals (Cd, Ni, Cr, Sn, and Fe) in surface sediments in the Bernam River. Nine surface sediment samples were collected from the lower, middle, and upper courses of the river. The results indicated that the concentrations of the metals decreased in the order of Sn > Cr > Ni > Fe > Cd (56.35, 14.90, 5.3, 4.6, and 0.62 μg/g(1) dry weight). Bernam River sediments have moderate to severe enrichment for Sn, moderate for Cd, and no enrichment for Cr, Ni, and Fe. The contamination factor (CF) results demonstrated that Cd and Sn are responsible for the high contamination. The pollution load index (PLI), for all the sampling sites, suggests that the sampling stations were generally unpolluted with the exception of the Bagan Tepi Sungai, Sabak Bernam, and Tanjom Malim stations. Multivariate techniques including Pearson's correlation and hierarchical cluster analysis were used to apportion the various sources of the metals. The results suggested that the sediment samples collected from the upper course of the river had lower metal concentrations, while sediments in the middle and lower courses of the river had higher metal concentrations. Therefore, our results can be useful as a baseline data for government bodies to adopt corrective measure on the issues related to heavy metal pollution in the Bernam River in the future. PMID:26614452

  14. 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

  15. Sediment contaminants and biological effects in southern California: Use of a multivariate statistical approach to assess biological impact

    SciTech Connect

    Maxon, C.L.; Barnett, A.M.; Diener, D.R.

    1997-04-01

    This study attempts to predict biological toxicity and benthic community impact in sediments collected from two southern California sites. Contaminant concentrations and grain size were evaluated as predictors using a two-step multivariate approach. The first step used principal component analysis (PCA) to describe contamination type and magnitude present at each site. Four dominant PC vectors, explaining 88% of the total variance, each corresponded to a unique physical and/or chemical signature. The four PC vectors, in decreasing order of importance, were: (1) high molecular weight polynuclear aromatic hydrocarbons (PAH), most likely from combusted or weathered petroleum; (2) low molecular weight alkylated PAH, primarily from weathered fuel product; (3) low molecular weight nonalkylated PAH, indicating a fresh petroleum-related origin; and (4) fine-grained sediments and metals. The second step used stepwise regression analysis to predict individual biological effects (dependent) variables using the four PC vectors as independent variables. Results showed that sediment grain size alone was the best predictor of amphipod mortality. Contaminant vectors showed discrete depositional areas independent of grain size. Neither contaminant concentrations nor PCA vectors were good predictors of biological effects, most likely due to the low concentrations in sediments.

  16. Heavy-metal-contaminated industrial soil: Uptake assessment in native plant species from Brazilian Cerrado.

    PubMed

    Meyer, Sylvia Therese; Castro, Samuel Rodrigues; Fernandes, Marcus Manoel; Soares, Aylton Carlos; de Souza Freitas, Guilherme Augusto; Ribeiro, Edvan

    2016-08-01

    Plants of the Cerrado have shown some potential for restoration and/or phytoremediation projects due to their ability to grow in and tolerate acidic soils rich in metals. The aim of this study is to evaluate the tolerance and accumulation of metals (Cd, Cu, Pb, and Zn) in five native tree species of the Brazilian Cerrado (Copaifera langsdorffii, Eugenia dysenterica, Inga laurina, Cedrela fissilis, Handroanthus impetiginosus) subjected to three experiments with contaminated soils obtained from a zinc processing industry (S1, S2, S3) and control soil (S0). The experimental design was completely randomized (factorial 5 × 4 × 3) and conducted in a greenhouse environment during a 90-day experimentation time. The plant species behavior was assessed by visual symptoms of toxicity, tolerance index (TI), translocation factor (TF), and bioaccumulation factor (BF). C. fissilis has performed as a Zn accumulator by the higher BFs obtained in the experiments, equal to 3.72, 0.88, and 0.41 for S1, S2, and S3 respectively. This species had some ability of uptake control as a defense mechanism in high stress conditions with the best behavior for phytoremediation and high tolerance to contamination. With economical and technical benefits, this study may support a preliminary analysis necessary for using native tree species in environmental projects. PMID:26852633

  17. Toxicological and chemical assessment of arsenic-contaminated groundwater after electrochemical and advanced oxidation treatments.

    PubMed

    Radić, Sandra; Crnojević, Helena; Vujčić, Valerija; Gajski, Goran; Gerić, Marko; Cvetković, Želimira; Petra, Cvjetko; Garaj-Vrhovac, Vera; Oreščanin, Višnja

    2016-02-01

    Owing to its proven toxicity and mutagenicity, arsenic is regarded a principal pollutant in water used for drinking. The objective of this study was the toxicological and chemical evaluation of groundwater samples obtained from arsenic enriched drinking water wells before and after electrochemical and ozone-UV-H2O2-based advanced oxidation processes (EAOP). For this purpose, acute toxicity test with Daphnia magna and chronic toxicity test with Lemna minor L. were employed as well as in vitro bioassays using human peripheral blood lymphocytes (HPBLs). Several oxidative stress parameters were estimated in L.minor. Physicochemical analysis showed that EAOP treatment was highly efficient in arsenic but also in ammonia and organic compound removal from contaminated groundwater. Untreated groundwater caused only slight toxicity to HPBLs and D. magna in acute experiments. However, 7-day exposure of L. minor to raw groundwater elicited genotoxicity, a significant growth inhibition and oxidative stress injury. The observed genotoxicity and toxicity of raw groundwater samples was almost completely eliminated by EAOP treatment. Generally, the results obtained with L. minor were in agreement with those obtained in the chemical analysis suggesting the sensitivity of the model organism in monitoring of arsenic-contaminated groundwater. In parallel to chemical analysis, the implementation of chronic toxicity bioassays in a battery is recommended in the assessment of the toxic and genotoxic potential of such complex mixtures. PMID:26580737

  18. Assessing atmospheric concentration of polychlorinated biphenyls by evergreen Rhododendron maximum next to a contaminated stream.

    PubMed

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

    2016-09-01

    Conifers are often used as an air passive sampler, but few studies have focused on the implication of broadleaf evergreens to monitor atmospheric semivolatile organic compounds such as polychlorinated biphenyls (PCBs). In the present study, the authors used Rhododendron maximum (rhododendron) growing next to a contaminated stream to assess atmospheric PCB concentrations. The present study area was located in a rural setting and approximately 2 km downstream of a former capacitor plant. Leaves from the same mature shrubs were collected in late fall 2010 and winter and spring 2011. Polychlorinated biphenyls were detected in the collected leaves, suggesting that rhododendron can be used as air passive samplers in rural areas where active sampling is impractical. Estimated ΣPCB (47 congeners) concentrations in the atmosphere decreased from fall 2010 to spring 2011 with concentration means at 3990 pg m(-3) , 2850 pg m(-3) , and 931 pg m(-3) in fall 2010, winter 2011, and spring 2011, respectively. These results indicate that the atmospheric concentrations at this location continue to be high despite termination of active discharge from the former industrial source. Leaves had a consistent pattern of high concentrations of tetra-CBs and penta-CBs similar to the congener distribution in polyethylene passive samplers deployed in the water column, suggesting that volatilized PCBs from the stream were the primary source of contaminants in rhododendron leaves. Environ Toxicol Chem 2016;35:2192-2198. © 2016 SETAC. PMID:26889751

  19. Concentrations, distribution, sources and risk assessment of organohalogenated contaminants in soils from Kenya, Eastern Africa.

    PubMed

    Sun, Hongwei; Qi, Yueling; Zhang, Di; Li, Qing X; Wang, Jun

    2016-02-01

    The organohalogenated contaminants (OCs) including 12 organochlorine pesticides (OCPs), 7 indicator polychlorinated biphenyls (PCBs) and 7 polybrominated diphenyl ethers (PBDEs) were determined in soils collected from Kenya, Eastern Africa. The total OCPs fell in the range of n.d-49.74 μg kg(-1) dry weight (dw), which was dominated by DDTs and endosulfan. Identification of pollution sources indicated new input of DDTs for malaria control in Kenya. The total PCBs ranged from n.d. to 55.49 μg kg(-1) dw, dominated by penta- and hexa-PCBs, probably associated with the leakage of obsolete transformer oil. The soils were less contaminated by PBDEs, ranging from 0.19 to 35.64 μg kg(-1) dw. The predominant PBDE congeners were penta-, tri- or tetra-BDEs, varying among different sampling sites. Risk assessment indicated potential human health risks posed by OCs in soils from Kenya, with PCBs as the most contributing pollutants. The local authorities are recommended to make best efforts on management of OC pollution, particularly from DDTs and PCBs to meet the requirement of Stockholm Convention. PMID:26686059

  20. Assessing atmospheric concentration of polychlorinated biphenyls (PCBs) by evergreen Rhododendron maximum next to a contaminated stream

    USGS Publications Warehouse

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

    2016-01-01

    Conifers are often used as an “air passive sampler”, but few studies have focused on the implication of broadleaf evergreens to monitor atmospheric semivolatile organic compounds such as polychlorinated biphenyls (PCBs). In this study, we used Rhododendron maximum (rhododendron) growing next to a contaminated stream to assess atmospheric PCB concentrations. The study area was located in a rural setting and approximately 2 km downstream of a former Sangamo-Weston (S-W) plant. Leaves from the same mature shrubs were collected in late fall 2010, and winter and spring 2011. PCBs were detected in the collected leaves suggesting that rhododendron can be used as air passive samplers in rural areas where active sampling is impractical. Estimated ΣPCB (47 congeners) concentrations in the atmosphere decreased from fall 2010 to spring 2011 with concentration means at 3990, 2850, and 931 pg m-3 in fall 2010, winter 2011, and spring 2011, respectively. These results indicate that the atmospheric concentrations at this location continue to be high despite termination of active discharge from the former S-W plant. Leaves had a consistent pattern of high concentrations of tetra- and penta-CBs similar to the congener distribution in polyethylene (PE) passive samplers deployed in the water column suggesting that volatilized PCBs from the stream were the primary source of contaminants in rhododendron leaves.

  1. Contamination assessment of mercury and arsenic in roadway dust from Baoji, China

    NASA Astrophysics Data System (ADS)

    Lu, Xinwei; Li, Loretta Y.; Wang, Lijun; Lei, Kai; Huang, Jing; Zhai, Yuxiang

    The physicochemical properties and the contamination levels of mercury and arsenic in roadway dust from Baoji, NW China were investigated using an Atomic Fluorescence Spectrophotometer. Contamination levels were assessed based on the geoaccumulation index and the enrichment factor. The results show that magnetic susceptibilities of roadway dust were higher than Holocene loess-soil of central Shaanxi Loess Plateau. The mean contents of organic matter, PM10 and PM100 were 8.8%, 21.8% and 98.6%, respectively. Mercury concentration ranged from 0.48 to 2.32 μg g -1, with a mean value of 1.11 μg g -1, 17.1 times the Chinese soil mercury background value and 37 times the Shaanxi soil mercury background value. Arsenic concentration ranged from 9.0 to 42.8 μg g -1, with a mean value of 19.8 μg g -1, 1.8 times the Chinese and Shaanxi soil arsenic background values. The geoaccumlation index and enrichment factor indicate that mercury in the dust mainly originated from anthropogenic sources with ratings of "strongly polluted" and "strongly to extremely polluted", whereas arsenic in dust originated from both natural and anthropogenic sources, with a ratings of "moderately to strongly polluted" and "strongly polluted". Industrial activities, such as a coal-fired power station, coke-oven plant, and cement manufacturing plant, augmented by vehicular traffic, are the anthropogenic sources of mercury and arsenic in the roadway dust.

  2. Assessing sites contaminated with unexploded ordnance: statistical modeling of ordnance spatial distribution.

    PubMed

    Macdonald, Jacqueline A; Small, Mitchell J

    2006-02-01

    More than 40,000 km2 of former military land in the United States are contaminated with unexploded ordnance (UXO). Cleanup costs are estimated to total as much as 140 billion dollars. The amount of contaminated acreage and total costs are likely to increase as the U.S. Department of Defense (DOD) follows through on recently announced plans to close an additional 22 domestic military bases. The U.S. Environmental Protection Agency(EPA) and DOD disagree on how these sites should be characterized to assess their risks and plan for cleanup. As a result, much potentially valuable land remains idle while remediation decisions are pending. One of the sources of disagreement is how the locations of UXO should be characterized, given that the exact spatial distribution of UXO is unknown in advance of cleanup. In this paper, we propose and test a new model to represent the spatial distribution of UXO. Unlike existing DOD models, the new model accounts for the tendency of UXO to cluster, presumably around targets at which soldiers aimed during training. We fit the cluster model to geographic data on UXO locations at two former military installations and show that it describes key characteristics of the data more accuratelythan the existing DOD model. We discuss how the choice of a UXO spatial distribution model could affect important decisions about cleaning up and reusing UXO-affected property. PMID:16509339

  3. Uses of probabilistic exposure models in ecological risk assessments of contaminated sites

    SciTech Connect

    MacIntosh, D.L.; Suter, G.W. II; Hoffman, F.O.

    1994-08-01

    Food web models have two uses in assessments of environmental contaminants. First, they are used to determine whether remediation is needed by estimating exposure of end-point species and subsequent effects. Second, they are used to establish cleanup goals by estimating concentrations of contaminants in ambient media that will not cause significant effects. This paper demonstrates how achievement of these goals can be enhanced by the use of stochastic food web models. The models simulate the dynamics of PCBs and mercury in the food webs of mink and great blue herons. All parameters of the models are treated as having knowledge uncertainty, due to imperfect knowledge of the actual parameter values for the site, chemicals, and species of interest. This uncertainty is an indicator of the potential value of additional measurements. In addition, those parameters that are responsible for variance among individual organisms are assigned stochastic uncertainty. This uncertainty indicates the range of body burdens that are expected when the end-point species are monitored. These two types of uncertainty are separately accounted for in Monte Carlo simulations of the models. Preliminary monitoring results indicate that the models give reasonably good estimates of heron egg and nestling body burdens and of variance among individuals. 20 refs, 7 refs., 3 tabs.

  4. Interrenal dysfunction in fish from contaminated sites: In vivo and in vitro assessment

    SciTech Connect

    Hontela, A.

    1998-01-01

    Cortisol, synthesized in the interrenal cells of teleost head kidney, has a major role in the physiologic response to physical and chemical stressors. Plasma levels of cortisol increase in physiologically competent fish acutely exposed to stressors such as cadmium or mercury. The effects of chronic low level exposures are less well understood. The author has diagnosed an endocrine impairment characterized by a reduced capacity to elevate plasma cortisol levels in response to an acute standardized capture stress in yellow perch (Perca flavescens) and in northern pike (Esox lucius) sampled at sites contaminated by mixtures of pollutants (heavy metals, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls), by heavy metals, or by bleached kraft mill effluent. The studies with fish, as well as with amphibians at contaminated sites, demonstrated that low level chronic exposures impair secretion of corticosteroids. The author has developed new tests for assessment of the functional integrity of teleost and amphibian interrenal tissue using an adrenocorticotropic hormone (ACTH) challenge, in vivo and in vitro. The reduced ability to respond to ACTH indicates that the normal neuroendocrine response to stressors may be disrupted and that the ability to cope with biotic and abiotic stressors in the environment may be significantly reduced in the impaired animals.

  5. TPH-contaminated Mexican refinery soil: health risk assessment and the first year of changes.

    PubMed

    Iturbe, Rosario; Flores, Rosa M; Flores, Carlos R; Torres, Luis G

    2004-02-01

    The soil of a coastal Mexican refinery is quite contaminated, especially by hydrocarbons, with detected concentrations up to 130000 mg kg(-1) as TPHs (total petroleum hydrocarbons). The main sources of contamination are pipelines, valves, and old storage tanks, besides the land disposal of untreated hydrocarbon sediments derived from the cleaning of storage tanks. A health risk assessment (HRA) was carried out in order to measure the risk hazard indexes and clean-up standards for the refinery soil. HRA suggested the following actions to be taken: benzene concentrations must be reduced in eight of the 16 studied refinery zones to 0.0074-0.0078 mg kg(-1). Also, vanadium concentration must be reduced in two zones up to a concentration of 100 mg kg(-1). In only one of all of the studied zones, benzo(a)pyrene concentration must be reduced to 0.1 mg kg(-1). After 1 yr, TPHs showed a diminution of about 52%. Even though TPHs concentrations were variable, during 1999 the average concentrations were as much as 15.5 times the goal concentration. For year 2000, TPHs concentrations were only 7.4-fold the proposed value. For the 1999-2000 period, PAHs (polycyclic aromatic hydrocarbons) concentrations decreased by 82%. Some PAHs with 2, 3, 4, and 5 aromatic rings were removed up to 100% values. PMID:14969447

  6. Assessment of co-contaminant effects on uranium and thorium speciation in freshwater using geochemical modelling.

    PubMed

    Lofts, Stephen; Fevrier, Laureline; Horemans, Nele; Gilbin, Rodolphe; Bruggeman, Christophe; Vandenhove, Hildegarde

    2015-11-01

    Speciation modelling of uranium (as uranyl) and thorium, in four freshwaters impacted by mining activities, was used to evaluate (i) the influence of the co-contaminants present on the predicted speciation, and (ii) the influence of using nine different model/database combinations on the predictions. Generally, co-contaminants were found to have no significant effects on speciation, with the exception of Fe(III) in one system, where formation of hydrous ferric oxide and adsorption of uranyl to its surface impacted the predicted speciation. Model and database choice on the other hand clearly influenced speciation prediction. Complexes with dissolved organic matter, which could be simulated by three of the nine model/database combinations, were predicted to be important in a slightly acidic, soft water. Model prediction of uranyl and thorium speciation needs to take account of database comprehensiveness and cohesiveness, including the capability of the model and database to simulate interactions with dissolved organic matter. Measurement of speciation in natural waters is needed to provide data that may be used to assess and improve model capabilities and to better constrain the type of predictive modelling work presented here. PMID:26225834

  7. Assessment of EDTA heap leaching of an agricultural soil highly contaminated with heavy metals.

    PubMed

    Hu, Pengjie; Yang, Bingfan; Dong, Changxun; Chen, Like; Cao, Xueying; Zhao, Jie; Wu, Longhua; Luo, Yongming; Christie, Peter

    2014-12-01

    The efficiency of heavy metal removal from soil by EDTA leaching was assessed in a column leaching experiment at the laboratory scale and field heap leaching at the pilot scale using a sandy loam sierozem agricultural soil contaminated with Cd, Cu, Pb, and Zn. Soil amendment and aging were conducted to recover leaching soils. The percentages of Cd, Cu, Pb, and Zn removed by column leaching were 90%, 88%, 90%, and 67%, respectively, when 3.9 bed volumes of 50mM EDTA were used. At the pilot scale, on-site metal removal efficiencies using the selected leaching procedure were 80%, 69%, 73% and 62% for Cd, Cu, Pb and Zn, respectively. EDTA leaching decreased soil CEC, total P, total K and available K concentrations but increased organic matter and total Kjeldahl N concentrations. The subsequent amendment and soil aging further reduced the DTPA-extractable heavy metals in the leached soils. Growth of the first crop of pak choi in the leached soil was inhibited but the second crop grew well after the soil was aged for one year and the concentrations of Cd and Pb in the edible parts were below the Chinese statutory limits. The results demonstrate the potential feasibility of the field leaching technique using EDTA combined with subsequent amendment and soil aging for the remediation of heavy metal-contaminated agricultural soils. PMID:25277965

  8. Perfluorocarbon tracer tagging of drilling muds for the assessment of sample contamination

    SciTech Connect

    Senum, G.I.; Dietz, R.N.

    1990-01-01

    Perfluorocarbon tracers, PFTs, a multitracer technology of seven chemical tracers, were used to tag the drilling muds used in the Fourth Investigators Hole of the Deep Probe experiments. PFTs are fully fluorinated alkyl substituted cycloalkanes, which are inert, non-toxic and chemically non-reactive, detectable in these applications to 1 picoliter/gram of sample by gas chromatographic electron capture detection. PFTs were incorporated into the drilling muds at the 100,000 p1/gm level by addition of a 1% PFT microemulsion in H{sub 2}O during the periodic preparation of drilling muds. A total of four different PFTs were used to tag the drilling mud used in the stratigraphic core and sample wells; two PFTs were used in the core well and two further PFTs in the sample well. After sampling, a small aliquot of samples was forwarded to the Tracer Technology Center (TTC) for PFT analysis along with samples of the tagged muds. The samples were centrifuged and headspace sampled for PFT. Results of the PFT analyses were then used to assess the degree of drilling mud contamination of the retrieved samples. The results indicated some contamination of the retrieved samples and some transport of fluids from the core well to the sampling well, which are quantitated by the measured PFT concentrations. 8 refs., 3 tabs.

  9. DASMI: exchanging, annotating and assessing molecular interaction data

    PubMed Central

    Blankenburg, Hagen; Finn, Robert D.; Prlić, Andreas; Jenkinson, Andrew M.; Ramírez, Fidel; Emig, Dorothea; Schelhorn, Sven-Eric; Büch, Joachim; Lengauer, Thomas; Albrecht, Mario

    2009-01-01

    Motivation: Ever increasing amounts of biological interaction data are being accumulated worldwide, but they are currently not readily accessible to the biologist at a single site. New techniques are required for retrieving, sharing and presenting data spread over the Internet. Results: We introduce the DASMI system for the dynamic exchange, annotation and assessment of molecular interaction data. DASMI is based on the widely used Distributed Annotation System (DAS) and consists of a data exchange specification, web servers for providing the interaction data and clients for data integration and visualization. The decentralized architecture of DASMI affords the online retrieval of the most recent data from distributed sources and databases. DASMI can also be extended easily by adding new data sources and clients. We describe all DASMI components and demonstrate their use for protein and domain interactions. Availability: The DASMI tools are available at http://www.dasmi.de/ and http://ipfam.sanger.ac.uk/graph. The DAS registry and the DAS 1.53E specification is found at http://www.dasregistry.org/. Contact: mario.albrecht@mpi-inf.mpg.de Supplementary information: Supplementary data and all figures in color are available at Bioinformatics online. PMID:19420069

  10. LMWOA (low molecular weight organic acid) exudation by salt marsh plants: Natural variation and response to Cu contamination

    NASA Astrophysics Data System (ADS)

    Mucha, Ana P.; Almeida, C. Marisa R.; Bordalo, Adriano A.; Vasconcelos, M. Teresa S. D.

    2010-06-01

    This work aimed to evaluate, in vitro, the capability of roots of two salt marsh plants to release low molecular weight organic acids (LMWOAs) and to ascertain whether Cu contamination would stimulate or not organic acids exudation. The sea rush Juncus maritimus and the sea-club rush Scirpus maritimus, both from the lower Douro river estuary (NW Portugal), were used. Plants were collected seasonally, four times a year in 2004, during low tide. After sampling, plant roots were washed for removal of adherent particles and immersed for 2 h in a solution that matched salinity (3) and pH (7.5) of the pore water from the same location to obtain plant exudates. In one of the seasons, similar experiments were carried out but spiking the solution with different amounts of Cu in order to embrace the range between 0 and 1600 nM. In the final solutions as well as in sediment pore water LMWOAs were determined by high performance liquid chromatography. Plants were able to release, in a short period of time, relatively high amounts of LMWOAs (oxalate, citrate, malate, malonate, and succinate). In the sediment pore water oxalate, succinate and acetate were also detected. Therefore, plant roots probably contributed to the presence of some of these organic compounds in pore water. Exudation differed between the plant species and also showed some seasonally variation, particularly for S. maritimus. The release of oxalate by J. maritimus increased with Cu increase in the media. However, exudation of the other LMWOAs did not seem to be stimulated by Cu contamination in the media. This fact is compatible with the existence of alternative internal mechanisms for Cu detoxification, as denoted by the fact that in media contaminated with Cu both plant species accumulated relatively high amounts (29-83%) of the initially dissolved Cu. This study expands our knowledge on the contribution of globally dominant salt marsh plants to the release of LMWOAs into the environment.

  11. Use of pesticide simulation models for assessing pesticide contamination of surface and groundwater

    SciTech Connect

    Nutter, W.L.; Bush, P.B.; Neary, D.G.; Dowd, J.F.

    1985-01-01

    Two field scale hydrologic and pesticide routing models, CREAMS (Chemicals, Runoff, and Erosion in Agricultural Management Systems) and PRZM (Pesticide Root Zone Model) were used to predict average pesticide concentrations in storm flow and unsaturated subsurface flow after application of forestry herbicides and insecticides. Forest regions in the mountain, Piedmont, and coastal plain physiographic provinces of the South provide important stream sources and groundwater recharge zones for municipal water supplies. Increasing use of herbicides and insecticides in forest management has raised concerns about maintaining future water quality. Thus tools for assessing potential contamination from pesticide use are needed. CREAMS accurately predicted herbicide concentrations in storm flow in mountain watersheds for 2 months. But it is underestimated concentrations for the next 4 months when transport processes not accounted for in the model dominated actual residue movement. PRZM was likewise tested with actual field data on subsurface movement of herbicides in mountain regions and insecticides in deep sands of the coastal plain.

  12. Treatability studies for uranium and plutonium contaminated soils using physical separation methods. Environmental Assessment

    SciTech Connect

    1992-07-01

    The Nevada Field Office of the Department of Energy (DOE/NV) has stated in the Environmental Restoration and Waste Management (ERWM) Site Specific Plan for the Nevada Test Site (NTS) that DOE/NV is committed to achieving compliance with all applicable environmental laws, regulations, guidelines, and agreements covering operations at the NTS. The primary DOE/NV objective identified by the Site-Specific Plan is to comply with all laws and regulations aimed at protecting human health and the environment. These include Nevada statutes and regulations which may be applicable, including federally delegated authorities. This environmental assessment discusses limited bench-scale soil treatability testing of physical processes for decontamination of plutonium- and uranium-contaminated soil. The proposed location of these studies would be the Treatability Testing Facility (TTF), Building 3124 at Test Cell ``All in Area 25 of the NTS.

  13. Epidemiologic approaches to assessing human cancer risk from consuming aquatic food resources from chemically contaminated water.

    PubMed Central

    Ozonoff, D; Longnecker, M P

    1991-01-01

    Epidemiologic approaches to assessing human cancer risk from consuming fish from contaminated waters must confront the problems of long latency and rarity of the end point (cancer). The latency problem makes determination of diet history more difficult, while the low frequency of cancer as an end point reduces the statistical power of the study. These factors are discussed in relation to the study designs most commonly employed in epidemiology. It is suggested that the use of biomarkers for persistent chemicals may be useful to mitigate the difficulty of determining exposure, while the use of more prevalent and timely end points, such as carcinogen-DNA adducts or oncogene proteins, may make the latency and rarity problems more tractable. PMID:2050052

  14. Public health assessment of dioxin-contaminated fish at former US airbase, Bien Hoa, Vietnam.

    PubMed

    Durant, James T; Boivin, Thomas G; Pohl, Hana R; Sinks, Thomas H

    2015-01-01

    Ponds at the former US airbase at Ben Hoa, Vietnam are contaminated with Agent Orange. The ponds had been used for aquaculture, and in all likelihood, fish from those ponds have been sold to the public. We assessed human exposure to 2,3,7,8-tetrachloro-dibenzo-dioxin (2,3,7,8-TCDD) in fish samples from the ponds. For on-base tilapia, muscle concentrations 2,3,7,8-TCDD ranged from 1.4 to 32.7 pg/g. Fat concentrations ranged from 73.3 to 3990 pg/g. Estimated human exposure doses exceed international guidelines and exceed 2,3,7,8-TCDD's lowest adverse effect levels. The Bien Hoa fishponds are a completed human pathway for TCDD exposure. PMID:25087452

  15. Assessing of Conceptual Models for Subsurface Reactive Transport of Inorganic Contaminants

    NASA Astrophysics Data System (ADS)

    Davis, James A.; Yabusaki, Steven B.; Steefel, Carl I.; Zachara, John M.; Curtis, Gary P.; Redden, George D.; Criscenti, Louise J.; Honeyman, Bruce D.

    2004-11-01

    In many subsurface situations where human health and environmental quality are at risk (e.g., contaminant hydrogeology, petroleum extraction, carbon sequestration, etc.), scientists and engineers are being asked by federal agency decision-makers to predict the fate of chemical species under conditions where both reactions and transport are processes of first-order importance. In 2002, a working group (WG) was formed by representatives of the U.S. Geological Survey, Environmental Protection Agency, Department of Energy, Nuclear Regulatory Commission, Department of Agriculture, and Army Engineer Research and Development Center to assess the role of reactive transport modeling (RTM) in addressing these situations. Specifically, the goals of the WG are to (1) evaluate the state of the art in conceptual model development and parameterization for RTM, as applied to soil, vadose zone, and groundwater systems, and (2) prioritize research directions that would enhance the practical utility of RTM.

  16. Baseline risk assessment of ground water contamination at the Uranium Mill Tailings Sites near Rifle, Colorado. Revision 2

    SciTech Connect

    1996-02-01

    The U.S. Department of Energy (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project consists of the Surface Project (Phase I) and the Ground Water Project (Phase II). Under the UMTRA Surface Project, tailings, radioactive contaminated soil, equipment, and materials associated with the former uranium ore processing sites are placed into disposal cells. The cells are designed to reduce radon and other radiation emissions and to prevent further ground water contamination. The Ground Water Project evaluates the nature and extent of ground water contamination resulting from the uranium ore processing activities. Two UMTRA Project sites are near Rifle, Colorado: the Old Rifle site and the New Rifle site. Surface cleanup at the two sites is under way and is scheduled for completion in 1996. The Ground Water Project is in its beginning stages. A risk assessment identifies a source of contamination, how that contamination reaches people and the environment, the amount of contamination to which people or the environment may be exposed, and the health or environmental effects that could result from that exposure. This report is a site-specific document that will be used to evaluate current and future impacts to the public and the environment from exposure to contaminated ground water. This evaluation and further site characterization will be used to determine if action is needed to protect human health or the environment. Human health risk may result from exposure to ground water contaminated from uranium ore processing. Exposure could occur from drinking water obtained from a well placed in the areas of contamination. Furthermore, environmental risk may result from plant or animal exposure to surface water and sediment that have received contaminated ground water.

  17. A method for assessing sublethal effects of contaminants in soils to the earthworm, Eisenia foetida

    SciTech Connect

    Gibbs, M.H.; Wicker, L.F.; Stewart, A.J.

    1996-03-01

    The authors developed and tested a procedure that allows quantification of the effects of soil contaminants on earthworm (Eisenia foetida) growth and reproduction. The procedure monitors isolated pairs of earthworms and generates a higher ratio of data per organisms than other commonly used procedures. It also incorporates an accurate technique for measuring adult growth, has high sensitivity compared to the Organization for Economic Cooperation and Development (OECD) 14-d acute toxicity test, and is cost effective. The authors applied the method to a variety of soil-testing problems. A food-and-substrate trial using artificial soil demonstrated the sensitivity of the method and the need for food supplementation to stimulate earthworm reproduction. Application of the procedure to assess efficacy of a soil bioremediation technology revealed the advantage of measuring both growth and reproduction and highlighted the usefulness of a single integrated measure of these two responses. The method also was used as a fast-screening analysis for field soils in a large-scale ecological risk assessment. Finally, a reference toxicant, used in dilution series, demonstrated that responses of E. foetida using the authors` method were similar to their responses in the OECD artificial-soil test method. The results of this study indicate that this procedure can be used both for regulatory and compliance needs within the framework of ecological risk assessment.

  18. Remedial policies in radiologically-contaminated forests: environmental consequences and risk assessment.

    PubMed

    Linkov, I; Morel, B; Schell, W R

    1997-02-01

    As a result of the Chernobyl nuclear power plant accident in 1986, large forested areas in Europe were contaminated by radionuclides. Extensive societal pressure has been exerted to decrease the radiation dose to the population and to the environment. Thus, in making abatement and remediation policy decisions not only economic costs, but also human and environmental risk assessment are desired. Forest remediation by organic layer removal, one of the most promising cleanup policies, is considered in this paper. Ecological risk assessment requires evaluation of the radionuclide distribution in forests. The FORESTPATH model is used for predicting the radionuclide fate in forest compartments after deposition as well as for evaluating the application of the remedial policy. Time of intervention and radionuclide deposition profile was predicted as being crucial for the remediation efficiency. Risk assessment conducted for a critical group of forest users in Belarus shows that consumption of forest products (berries and mushrooms) leads to about 0.004% risk of a fatal cancer. Cost-benefit analysis for forest cleanup suggests that complete removal of organic layer is too expensive for application in Belarus. PMID:9131826

  19. Application of data fusion in human health risk assessment for hydrocarbon mixtures on contaminated sites.

    PubMed

    Dyck, Roberta; Islam, M Shafiqul; Zargar, Amin; Mohapatra, Asish; Sadiq, Rehan

    2013-11-16

    The exposure and toxicological data used in human health risk assessment are obtained from diverse and heterogeneous sources. Complex mixtures found on contaminated sites can pose a significant challenge to effectively assess the toxicity potential of the combined chemical exposure and to manage the associated risks. A data fusion framework has been proposed to integrate data from disparate sources to estimate potential risk for various public health issues. To demonstrate the effectiveness of the proposed data fusion framework, an illustrative example for a hydrocarbon mixture is presented. The Joint Directors of Laboratories Data Fusion architecture was selected as the data fusion architecture and Dempster-Shafer Theory (DST) was chosen as the technique for data fusion. For neurotoxicity response analysis, neurotoxic metabolites toxicological data were fused with predictive toxicological data and then probability-boxes (p-boxes) were developed to represent the toxicity of each compound. The neurotoxic response was given a rating of "low", "medium" or "high". These responses were then weighted by the percent composition in the illustrative F1 hydrocarbon mixture. The resulting p-boxes were fused according to DST's mixture rule of combination. The fused p-boxes were fused again with toxicity data for n-hexane. The case study for F1 hydrocarbons illustrates how data fusion can help in the assessment of the health effects for complex mixtures with limited available data. PMID:23219588

  20. Environmental monitoring and ecological risk assessment for pesticide contamination and effects in Lake Pamvotis, northwestern Greece.

    PubMed

    Hela, Dimitra G; Lambropoulou, Dimitra A; Konstantinou, Ioannis K; Albanis, Triantafyllos A

    2005-06-01

    Monitoring of pesticide residues in water and sediments was conducted as a basis for subsequent ecotoxicological risk assessment for the shallow eutrophic Lake Pamvotis, northwestern Greece. During a one-year study period, atrazine, desethylatrazine (DEA), simazine, diazinon, malathion, oxamyl, carbofuran, and ethion were detected in water and atrazine, desethylatrazine, diazinon, and s-ethyl dipropylthiocarbamate (EPTC) in sediments, all at ppb concentration level. Temporal variation in pesticide concentrations was observed. Highest residue levels for most pesticides in both water and sediment matrices occurred in the May to July period with the exception of atrazine and DEA, which show highest levels in water during the September to November period. The ecological risk associated with pesticide contamination was assessed using two different methods: The toxic unit method, which provides a first indication of the relative contribution of detected pesticides to the total toxicity and a probabilistic approach, and the inverse method of Van Straalen and Denneman, which is used to quantify the ecological risk. The maximum percentage of the ecological risk was 10.3 and 51.8% for water and 17.2 and 70.6% for sediment, based on acute and chronic level, respectively. These results show that pesticides exert a significant pressure on the aquatic system of Lake Pamvotis, especially for the chronic-effect level. Simple quotient methods should be coupled with higher-tier risk assessment, especially if restoration activities on lake ecosystems are to be undertaken for sustainable development. PMID:16117136

  1. Evaluating the applicability of regulatory leaching tests for assessing lead leachability in contaminated shooting range soils.

    PubMed

    Cao, Xinde; Dermatas, Dimitris

    2008-04-01

    The toxicity characteristic leaching procedure (TCLP) is the current US-EPA standard protocol to evaluate metal leachability in wastes and contaminated soils. However, application of TCLP to assess lead (Pb) leachability from contaminated shooting range soils may be questionable. This study determined Pb leachability in the range soils using TCLP and another US-EPA regulatory leaching method, synthetic precipitation leaching procedure (SPLP). Possible mechanisms that are responsible for Pb leaching in each leaching protocol were elucidated via X-ray diffraction (XRD). Soil samples were collected from the backstop berms at four shooting ranges, with Pb concentrations ranging from 5,000 to 60,600 mg kg(-1) soil. Lead concentrations in the TCLP leachates were from 3 to 350 mg l(-1), with all but one soil exceeding the USEPA non-hazardous waste disposal limit of 5 mg l(-1). However, continued dissolution of metallic Pb particles from spent Pb bullets and its re-precipitation as cerussite (PbCO(3)) prevented the TCLP extraction from reaching equilibrium at the end of the standard leaching period (18 h). Thus, the standard one-point TCLP test would either over- or under-estimate Pb leachability in shooting range soils. Lead concentration in the SPLP leachates ranged from 0.021 to 2.6 mg l(-1), with all soils above the USEPA regulatory limit of 0.015 mg l(-1). In contrast to TCLP, SPLP leaching had reached equilibrium, with regard to both pH and Pb concentrations, within the standard 18 h leaching period, and the analytical SPLP results were in good agreement with those derived from modeling. Thus, we concluded that SPLP is a more appropriate alternative than TCLP for assessing lead leachability in range soils. PMID:18204911

  2. Occupational Exposure Assessment of Airborne Chemical Contaminants Among Professional Ski Waxers

    PubMed Central

    Freberg, Baard Ingegerdsson; Olsen, Raymond; Daae, Hanne Line; Hersson, Merete; Thorud, Syvert; Ellingsen, Dag G.; Molander, Paal

    2014-01-01

    Background: Ski waxes are applied onto the skis to improve the performance. They contain different chemical substances, e.g. perfluoro-n-alkanes. Due to evaporation and sublimation processes as well as mechanically generated dust, vapours, fumes, and particulates can contaminate the workroom atmosphere. The number of professional ski waxers is increasing, but occupational exposure assessments among professional ski waxers are lacking. Objectives: The aim was to assess exposure to airborne chemical contaminants among professional ski waxers. It was also a goal to construct a ventilation system designed for ski waxing work operations. Methods: Forty-five professional ski waxers were included. Personal measurements of the inhalable and the respirable aerosol mass fractions were executed in 36 different waxing cabins using Conical Inhalable Sampler cassettes equipped with 37-mm PVC filters (5 µm) and Casella respirable cyclones equipped with 37-mm PVC filters (0.8 µm), respectively. Volatile organic components were collected using Anasorb CSC charcoal tubes. To examine time trends in exposure patterns, stationary real-time measurements of the aerosol mass fractions were conducted using a direct-reading Respicon® sampler. Results: Mean aerosol particle mass concentrations of 3.1 mg·m−3 (range: 0.2–12.0) and 6.2 mg·m−3 (range: 0.4–26.2) were measured in the respirable and inhalable aerosol mass fractions, respectively. Real-time aerosol sampling showed large variations in particle concentrations, with peak exposures of ~10 and 30 mg·m−3 in the respirable and the inhalable aerosol particle mass fractions, respectively. The custom-made ventilation system reduced the concentration of all aerosol mass fractions by more than 90%. PMID:24607772

  3. Immunohistochemical and molecular biomarkers in Coris julis exposed to environmental contaminants.

    PubMed

    Fasulo, Salvatore; Mauceri, Angela; Maisano, Maria; Giannetto, Alessia; Parrino, Vincenzo; Gennuso, Florinda; D'Agata, Alessia

    2010-07-01

    When a contaminant interacts with biotic components of a marine ecosystem, it causes a series of changes that can compromise an entire community (Stebbing, 1985). This present study wants to focus on changes in the gills of a bioindicator benthic organism, Coris julis, collected in Milazzo (Messina, Italy), characterized by a strong anthropical impact), compared with individuals from the control site (Marinello, Messina). RT-PCR has been used for both MT and HSP70, and the respective mRNAs have been visualized by FISH. MT and HSP70 expression levels increased in individuals collected in Milazzo. The presence of numerous apoptotic and proliferating cells and the analysis of several neuronal markers by immunohistochemical method give information about the adaptation to a heavy metal mixture. The obtained results show that, in stressed fishes, defensive processes increase to maintain the normal functions of the organs more exposed to the action of polluted substances. PMID:20129668

  4. Molecular approach to evaluate biostimulation of 1,2-dibromoethane in contaminated groundwater.

    PubMed

    Baek, Kyunghwa; McKeever, Robert; Rieber, Kahlil; Sheppard, Diane; Park, Chul; Ergas, Sarina J; Nüsslein, Klaus

    2012-11-01

    This study investigated the effect of co-substrate amendments on EDB biodegradation under aerobic conditions. Microcosms were established using contaminated soil and groundwater samples and maintained under in situ conditions to determine EDB degradation rates, and the diversity and abundance of EDB degrading indigenous bacteria. After 100days of incubation, between 25% and 56% of the initial EDB was degraded in the microcosms, with added jet fuel providing highest degradation rates (2.97±0.49yr(-1)). In all microcosms, the quantity of dehalogenase genes did not change significantly, while the number of BTEX monooxygenase and phenol hydroxylase genes increased with jet fuel amendments. These results indicate that EDB was not degraded by prior dehalogenation, but rather by cometabolism with adapted indigenous microorganisms. This is also reflected in the history of the plume, which originated from an aviation gasoline pipeline leak. This study suggests that biostimulation of EDB is possible at aerobic groundwater sites. PMID:22940321

  5. 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

  6. Baseline risk assessment of ground water contamination at the uranium mill tailings sites near Rifle, Colorado. Revision 1

    SciTech Connect

    1995-08-01

    The US Department of Energy (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project consists of the Surface Project (Phase 1) and the Ground Water Project (Phase 2). Under the UMTRA Surface Project, tailings, radioactive contaminated soil, equipment, and materials associated with the former uranium ore processing sites are placed into disposal cells. The cells are designed to reduce radon and other radiation emissions and to prevent further ground water contamination. The Ground Water Project evaluates the nature and extent of ground water contamination resulting from the uranium ore processing activities. Two UMTRA Project sites are near Rifle, Colorado: the Old Rifle site and the New Rifle site. Surface cleanup at the two sites is under way and is scheduled for completion in 1996. The Ground Water Project is in its beginning stages. A risk assessment identifies a source of contamination, how that contamination reaches people and the environment, the amount of contamination to which people or the environment may be exposed, and the health or environmental effects that could result from that exposure. This report is a site-specific document that will be used to evaluate current and future impacts to the public and the environment from exposure to contaminated ground water. This evaluation and further site characterization will be used to determine if action is needed to protect human health or the environment.

  7. Assessment of ground-water contamination by coal-tar derivatives, St. Louis Park area, Minnesota

    USGS Publications Warehouse

    Hult, M.F.

    1984-01-01

    Contaminants reached the Ironton-Galesville aquifer through at least two deep multiaquifer wells (W23 and W38), but the extent of contamination in this aquifer, and in the underlying Mount Simon-Hinckley aquifer, is not known.

  8. ASSESSING THE ROLE OF NATURAL ATTENUATION FOR INORGANIC CONTAMINANT REMEDIATION IN GROUND WATER

    EPA Science Inventory

    Monitored natural attenuation (MNA) has been applied as a knowledge-based remediation technology for organic contaminants in ground water. The application of this technology is being considered for remediation of inorganic contaminants in ground water at hazardous waste sites. ...

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

    SciTech Connect

    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 Project 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.

  10. Assessment of metal contamination in coastal sediments of the Maluan Bay (China) using geochemical indices and multivariate statistical approaches.

    PubMed

    Wang, Zaosheng; Wang, Yushao; Chen, Liuqin; Yan, Changzhou; Yan, Yijun; Chi, Qiaoqiao

    2015-10-15

    Total concentrations and chemical forms of heavy metals in surface sediments of Maluan Bay were determined and multiple geochemical indices and guidelines were applied to assess potential contamination and environmental risks. Metal concentrations exhibited significant spatial variation and the speciation of Cr was presented dominantly in the residual fraction, while Cd was found mostly in the non-residual fraction and thus of high potential bioavailability. Cluster analysis separated four subgroups of sampling sites with different levels of contamination. Further, a multivariate method offered the specific interpretation of possible contaminant sources and/or pathways. Factor scores characterized the sampling locations and elucidated the pollution status, pointing out the impact of multiple "hidden hotspots" of contaminants and providing further evidence of the existence of clear pollution-risk gradients in lagoon areas. The study supports the integrative approach as powerful tool to diagnose the pollution status scientifically for management decisions in coastal sediment of complex environment. PMID:26233304

  11. 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. PMID:27424247

  12. Molecular Analysis of Microbial Community Structures in Pristine and Contaminated Aquifers: Field and Laboratory Microcosm Experiments

    PubMed Central

    Shi, Y.; Zwolinski, M. D.; Schreiber, M. E.; Bahr, J. M.; Sewell, G. W.; Hickey, W. J.

    1999-01-01

    This study used phylogenetic probes in hybridization analysis to (i) determine in situ microbial community structures in regions of a shallow sand aquifer that were oxygen depleted and fuel contaminated (FC) or aerobic and noncontaminated (NC) and (ii) examine alterations in microbial community structures resulting from exposure to toluene and/or electron acceptor supplementation (nitrate). The latter objective was addressed by using the NC and FC aquifer materials for anaerobic microcosm studies in which phylogenetic probe analysis was complemented by microbial activity assays. Domain probe analysis of the aquifer samples showed that the communities were predominantly Bacteria; Eucarya and Archaea were not detectable. At the phylum and subclass levels, the FC and NC aquifer material had similar relative abundance distributions of 43 to 65% β- and γ-Proteobacteria (B+G), 31 to 35% α-Proteobacteria (ALF), 15 to 18% sulfate-reducing bacteria, and 5 to 10% high G+C gram positive bacteria. Compared to that of the NC region, the community structure of the FC material differed mainly in an increased abundance of B+G relative to that of ALF. The microcosm communities were like those of the field samples in that they were predominantly Bacteria (83 to 101%) and lacked detectable Archaea but differed in that a small fraction (2 to 8%) of Eucarya was detected regardless of the treatment applied. The latter result was hypothesized to reflect enrichment of anaerobic protozoa. Addition of nitrate and/or toluene stimulated microbial activity in the microcosms, but only supplementation of toluene alone significantly altered community structures. For the NC material, the dominant subclass shifted from B+G to ALF, while in the FC microcosms 55 to 65% of the Bacteria community was no longer identifiable by the phylum or subclass probes used. The latter result suggested that toluene exposure fostered the proliferation of phylotype(s) that were otherwise minor constituents of the

  13. 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

  14. CAirTOX, An inter-media transfer model for assessing indirect exposures to hazardous air contaminants

    SciTech Connect

    McKone, T.E.

    1994-01-01

    Risk assessment is a quantitative evaluation of information on potential health hazards of environmental contaminants and the extent of human exposure to these contaminants. As applied to toxic chemical emissions to air, risk assessment involves four interrelated steps. These are (1) determination of source concentrations or emission characteristics, (2) exposure assessment, (3) toxicity assessment, and (4) risk characterization. These steps can be carried out with assistance from analytical models in order to estimate the potential risk associated with existing and future releases. CAirTOX has been developed as a spreadsheet model to assist in making these types of calculations. CAirTOX follows an approach that has been incorporated into the CalTOX model, which was developed for the California Department of Toxic Substances Control, With CAirTOX, we can address how contaminants released to an air basin can lead to contamination of soil, food, surface water, and sediments. The modeling effort includes a multimedia transport and transformation model, exposure scenario models, and efforts to quantify uncertainty in multimedia, multiple-pathway exposure assessments. The capacity to explicitly address uncertainty has been incorporated into the model in two ways. First, the spreadsheet form of the model makes it compatible with Monte-Carlo add-on programs that are available for uncertainty analysis. Second, all model inputs are specified in terms of an arithmetic mean and coefficient of variation so that uncertainty analyses can be carried out.

  15. The geochemical evolution of low-molecular-weight organic acids derived from the degradation of petroleum contaminants in groundwater

    USGS Publications Warehouse

    Cozzarelli, I.M.; Baedecker, M.J.; Eganhouse, R.P.; Goerlitz, D.F.

    1994-01-01

    The geochemical evolution of low-molecular-weight organic acids in groundwater downgradient from a crude-oil spill near Bemidji, Minnesota, was studied over a five year period (1986-1990). The organic acids are metabolic intermediates of the degradation of components of the crude oil and are structurally related to hydrocarbon precursors. The concentrations of organic acids, particularly aliphatic acids, increase as the microbial alteration of hydrocarbons progresses. The organic-acid pool changes in composition and concentration over time and in space as the degradation processes shift from Fe(III) reduction to methanogenesis. Over time, the aquifer system evolves into one in which the groundwater contains more oxidized products of hydrocarbon degradation and the reduced forms of iron, manganese, and nitrogen. Laboratory microcosm experiments with aquifer material support the hypothesis that organic acids observed in the groundwater originate from the microbial degradation of aromatic hydrocarbons under anoxic conditions. The geochemistry of two other shallow aquifers in coastal plain sediments, one contaminated with creosote waste and the other with gasoline, were compared to the Bemidji site. The geochemical evolution of the low-molecular-weight organic acid pool in these systems is controlled, in part, by the presence of electron acceptors available for microbially mediated electron-transfer reactions. The depletion of electron acceptors in aquifers leads to the accumulation of aliphatic organic acids in anoxic groundwater. ?? 1994.

  16. The geochemical evolution of low-molecular-weight organic acids derived from the degradation of petroleum contaminants in groundwater

    SciTech Connect

    Cozzarelli, I.M.; Baedecker, M.J.; Eganhouse, R.P. ); Goerlitz, D.F. )

    1994-01-01

    The geochemical evolution of low-molecular-weight organic acids in groundwater downgradient from a crude-oil spill near Bemidji, Minnesota, was studied over a five year period (1986-90). The organic acids are metabolic intermediates of the degradation of components of the crude oil and are structurally related to hydrocarbon precursors. The concentrations of organic acids, particularly aliphatic acids, increase as the microbial alteration of hydrocarbons progresses. The organic-acid pool changes in composition and concentration over time and in space as the degradation processes shift from Fe(III) reduction to methanogenesis. Over time, the aquifer system evolves into one in which the groundwater contains more oxidized products of hydrocarbon degradation and the reduced forms of iron, manganese, and nitrogen. Laboratory microcosm experiments with aquifer material support the hypothesis that organic acids observed in the groundwater originate from the microbial degradation of aromatic hydrocarbons under anoxic conditions. The geochemistry of two other shallow aquifers in coastal plain sediments, one contaminated with creosote waste and the other with gasoline, were compared to the Bemidji site. The geochemical evolution of the low-molecular-weight organic acid pool in these systems is controlled, in part, by the presence of electron acceptors available for microbially mediated electron-transfer reactions. The depletion of electron acceptors in aquifers leads to the accumulation of aliphatic organic acids in anoxic groundwater.

  17. 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.

  18. 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.

  19. Treatability assessment of polycyclic aromatic hydrocarbons contaminated marine sediments using permanganate, persulfate and Fenton oxidation processes.

    PubMed

    Shih, Yu-Jen; Binh, Nguyen Thanh; Chen, Chiu-Wen; Chen, Chih-Feng; Dong, Cheng-Di

    2016-05-01

    Various chemical oxidation techniques, such as potassium permanganate (KMnO4), sodium persulfate (Na2S2O8), Fenton (H2O2/Fe(2+)), and the modified persulfate and Fenton reagents (activated by ferrous complexes), were carried out to treat marine sediments that were contaminated with polycyclic aromatic hydrocarbons (PAHs) and dredged from Kaohsiung Harbor in Taiwan. Experimental results revealed that KMnO4 was the most effective of the tested oxidants in PAH degradation. Owing to the high organic matter content in the sediment that reduced the efficiencies of Na2S2O8 and regular Fenton reactions, a large excess of oxidant was required. Nevertheless, KH2PO4, Na4P2O7 and four chelating agents (EDTA, sodium citrate, oxalic acid, and sodium oxalate) were utilized to stabilize Fe(II) in activating the Na2S2O8 and Fenton oxidations, while Fe(II)-citrate remarkably promoted the PAH degradation. Increasing the molecular weight and number of rings of PAH did not affect the overall removal efficiencies. The correlation between the effectiveness of the oxidation processes and the physicochemical properties of individual PAH was statistically analyzed. The data implied that the reactivity of PAH (electron affinity and ionization potential) affected its treatability more than did its hydrophobicity (Kow, Koc and Sw), particularly using experimental conditions under which PAHs could be effectively oxidized. PMID:26915591

  20. Using molecular tools to assess biofilms in onsite systems.

    PubMed

    Flapper, T G; McKay, A; Hall, S; Hill, P

    2007-01-01

    Onsite sewage treatment is growing in diversity, and in regulatory control across Australia. This is occurring for both blackwater and greywater treatment, as the drought impact deepens and more of the community are exposed to options for 'managing' their own water. Regulators in each State are drafting and implementing Guidelines to cover a range of on-site system scenarios. In addition, more and more decentralised options are being tendered for sewage management in the commercial world. In this project we aim to use novel molecular tools, in combination with traditional physical/chemical/biological methods, to understand onsite treatment in a more detailed manner. The system tested is a new peat based biofilter which can be used for greywater or blackwater application, and can be retrofitted to current sewage systems. This project has been based on the AquaReuse greywater system for demonstration purposes, showing the strength of the information gained from the use of novel tools. The two systems investigated are installed at a caravan park in New South Wales (NSW) and a domestic residence in Tamborine, Queensland (OLD). A 20-week intensive sampling and analysis program was followed. The project monitored standard analytes such as biochemical oxygen demand (BOD5), suspended solids (SS) and thermotolerant coliforms (TC). Additionally, we studied the biological community using fluorescent in situ hybridisation (FISH) on a monthly basis and full-cycle ribosomal RNA analysis (rRNA) for one sample to assess the biological community inhabitants. rRNA analysis at the NSW facility demonstrated a highly diverse biological community, in keeping with its long established operating period. In contrast, FISH analysis at the OLD installation showed a less diverse and younger community. rRNA and FISH identified organisms that are mostly associated with nutrient removing functions. PMID:17506424

  1. 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.

  2. Molecular- and cultural-based monitoring of bioremediation at a TCE-contaminated site

    SciTech Connect

    Brockman, F.J.; Payne, W.; Soong, A.; Manley, S.; Workman, D.; Sun, W.; Ogram, A.

    1995-12-31

    Sediment samples from a trichloroethylene (TCE)-contaminated zone 30 to 47 m below ground surface were analyzed after various nutrient addition strategies, including injection of air, 1% methane (in air), 4% methane (in air) pulsed with air, and multiple nutrients. Methanotroph most probable number (MPN) values in samples taken after the N/P/pulsed 4% methane campaign increased approximately two orders of magnitude compared to before-methane samples. The frequency of TCE biodegradative potential in methanotroph enrichments from samples taken after the N/P/pulsed 4% methane campaign was orders of magnitude greater than in all previous campaigns, indicating that in situ microbial activity was very strongly affected by adding nitrogen and phosphorus. The frequency of detection of the soluble methane monooxygenase and methanol dehydrogenase sequences was highest in sediment samples taken after the 1% methane campaign. Comparing the culture-dependent method with the culture-independent gene probe method showed that the culture method greatly underestimated the methanotrophic biomass in sediments throughout the demonstration.

  3. Chemical and toxicologic assessment of organic contaminants in surface water using passive samplers

    USGS Publications Warehouse

    Alvarez, D.A.; Cranor, W.L.; Perkins, S.D.; Clark, R.C.; Smith, S.B.

    2008-01-01

    Passive sampling methodologies were used to conduct a chemical and toxicologic assessment of organic contaminants in the surface waters of three geographically distinct agricultural watersheds. A selection of current-use agrochemicals and persistent organic pollutants, including polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and organochlorine pesticides, were targeted using the polar organic chemical integrative sampler (POCIS) and the semipermeable membrane device passive samplers. In addition to the chemical analysis, the Microtox assay for acute toxicity and the yeast estrogen screen (YES) were conducted as potential assessment tools in combination with the passive samplers. During the spring of 2004, the passive samplers were deployed for 29 to 65 d at Leary Weber Ditch, IN; Morgan Creek, MD; and DR2 Drain, WA. Chemical analysis of the sampler extracts identified the agrochemicals predominantly used in those areas, including atrazine, simazine, acetochlor, and metolachlor. Other chemicals identified included deethylatrazine and deisopropylatrazine, trifluralin, fluoranthene, pyrene, cis- and trans-nonachlor, and pentachloroanisole. Screening using Microtox resulted in no acutely toxic samples. POCIS samples screened by the YES assay failed to elicit a positive estrogenic response. Copyright ?? 2008 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

  4. An Alternative Approach to Assess the Habitat Selection of Folsomia candida in Contaminated Soils.

    PubMed

    Bori, Jaume; Riva, Maria Carme

    2015-11-01

    Avoidance tests with collembolans provide a quick assessment of soil quality. However, some parameters of the procedure can be modified in order to increase its performance. In this study we assessed the tendency of Folsomia candida to avoid soils contaminated with boric acid [350-700-1400-2800-5600 mg/kg soil dry weight (dw)], phenmedipham (35-70-140-280 mg/kg dw) or petroleum hydrocarbons (1312-1838-2625-3675-5250 mg/kg dw) by preferring an untreated soil. Two separate methodologies were applied, the one presented in the ISO standard 17512:2 and a modified version of the Petri dish method that allowed data acquisition after 2, 24 and 48 h of exposure. After combining data from three separate trials, effective median concentration values (EC50) from the presented method were lower and showed similar or less variability than those from the ISO procedure, suggesting the modified protocol as a suitable alternative screening tool. PMID:26350730

  5. Ecotoxicological assessment of bioremediation of a petroleum hydrocarbon-contaminated soil

    SciTech Connect

    Renoux, A.Y.; Tyagi, R.D.; Roy, Y.; Samson, R.

    1995-12-31

    A battery of bioassays [barley seed germination, barley plant growth, lettuce seed germination, worm mortality, Microtox{reg_sign}, lettuce root elongation, algae Selenastrum capricornutum growth, Daphnia magna mortality, and SOS Chromotest ({+-}S9)] was used to assess an above-ground heap pile treatment of a soil contaminated with aliphatic petroleum hydrocarbons (12 to 24 carbons). Despite an initial oil and grease concentration of 2,000 mg/kg, no significant (geno)toxicity was apparent in the soil sample before treatment. During the treatment, which decreased oil and grease concentrations to 800 mg/kg, slight toxicity was revealed by three bioassays (barley seed germination, worm mortality, Daphnia magna mortality), and a significant increase in genotoxicity was measured with the SOS Chromotest ({+-} S9). It appears that ecotoxicological evaluation revealed harmful condition(s) that were not detected by chemical assessment. This suggests that the remediation had ceased before complete detoxification occurred. This phenomenon must be further investigated, however, to furnish solid conclusions on the toxicological effectiveness of the biotreatment.

  6. Risk assessment of particle dispersion and trace element contamination from mine-waste dumps.

    PubMed

    Romero, Antonio; González, Isabel; Martín, José María; Vázquez, María Auxiliadora; Ortiz, Pilar

    2015-04-01

    In this study, a model to delimit risk zones influenced by atmospheric particle dispersion from mine-waste dumps is developed to assess their influence on the soil and the population according to the concentration of trace elements in the waste. The model is applied to the Riotinto Mine (in SW Spain), which has a long history of mining and heavy land contamination. The waste materials are separated into three clusters according to the mapping, mineralogy, and geochemical classification using cluster analysis. Two of the clusters are composed of slag, fresh pyrite, and roasted pyrite ashes, which may contain high concentrations of trace elements (e.g., >1 % As or >4 % Pb). The average pollution load index (PLI) calculated for As, Cd, Co, Cu, Pb, Tl, and Zn versus the baseline of the regional soil is 19. The other cluster is primarily composed of sterile rocks and ochreous tailings, and the average PLI is 3. The combination of particle dispersion calculated by a Gaussian model, the PLI, the surface area of each waste and the wind direction is used to develop a risk-assessment model with Geographic Information System GIS software. The zone of high risk can affect the agricultural soil and the population in the study area, particularly if mining activity is restarted in the near future. This model can be applied to spatial planning and environmental protection if the information is complemented with atmospheric particulate matter studies. PMID:25190539

  7. MOLECULAR EPIDEMIOLOGY: POTENTIAL IMPACTS ON THE ASSESSMENT OF PUBLIC HEALTH

    EPA Science Inventory

    Introduction

    The term "molecular epidemiology" has been used to cover a broad range of scientific activities, often without specific reference to epidemiology. In fact, as noted by Foxman and Riley [1],molecular epidemiology has often been described almost exclusively in...

  8. 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. PMID:21624662

  9. Molecular typing of the Legionella pneumophila population isolated from several locations in a contaminated water network.

    PubMed

    Lepeuple, A S; Jovic, M; de Roubin, M R

    2004-01-01

    The RAPD (random amplified polymorphic DNA) technique has been developed for the molecular typing of Legionella in order to characterise the populations of hot water systems. During this study, 22 primers were tested and the four most informative ones were selected. The optimisation of the PCR conditions allowed the setting up of a powerful discriminative genotyping method. Moreover, the definition of a quality management method allowed definition of the key steps and the number of replicates to ensure reproducibility of the RAPD pattern. The RAPD was used to study the hot water network of a building. Legionella colonies (91) were isolated from seven locations and genotyped. The diversity of the population in one sample could vary from one to seven different strains. The study of the traceability showed that, in most of the cases, different populations could be present at different locations of the same network. PMID:15318523

  10. Numerical Assessment of Indoor Air Exposure Risk from Subsurface NAPL Contamination under Hydrologic Uncertainties

    NASA Astrophysics Data System (ADS)

    Unger, A.; Yu, S.

    2007-12-01

    Understanding the risk of indoor air exposure to residual contaminants in the subsurface following the redevelopment of contaminated land redevelopment project is a central issue at many brownfield sites. In this study, we examine various mechanisms controlling vapor phase intrusion into the indoor air of a typical residential dwelling from a NAPL source located below the water table, and consequently assess the indoor air exposure risk under multiple hydrologic uncertainties. For this purpose, a multi-phase multi-component numerical model, CompFlow Bio is used to simulate the evolution of a TCE source zone and dissolved plume in a variably saturated heterogeneous aquifer, along with the transport of dissolved TCE upwards through the capillary fringe with subsequent migration of TCE vapors in the vadose zone subject to barometric pressure fluctuations. The TCE vapors then enter the basement of the residential dwelling through a crack in the foundation slab, driven by a slight vacuum within the basement relative to the ambient atmosphere as well as the barometric pressure fluctuations. Hydrologic uncertainties affecting the indoor air concentration of TCE include the vacuum in the basement, the aperture of the crack in the foundation slab, the heterogeneous permeability field, the thickness of the capillary fringe, barometric fluctuations, recharge rates and the location of the TCE source zone. CompFlow Bio is then used to determine the future concentration of TCE into the basement as a consequence of imperfect knowledge in the various hydrologic parameters, and to evaluate the effectiveness of alternative remedial and foundation design options to minimize the exposure risk to the indoor air conditional upon the available data collected at the site. The outcome of this approach is two-fold. First, the owner of the site can reasonably evaluate the future indoor air exposure risk following the redevelopment of a formerly contaminated site following remediation

  11. A review of soil cadmium contamination in China including a health risk assessment.

    PubMed

    Wang, Lin; Cui, Xiangfen; Cheng, Hongguang; Chen, Fei; Wang, Jiantong; Zhao, Xinyi; Lin, Chunye; Pu, Xiao

    2015-11-01

    Cadmium (Cd) is one of the most serious soil contaminants in China, and it poses an increasing risk to human health as large amounts of Cd are emitted into the environment. However, knowledge about soil Cd concentrations and the human health risks of these concentrations at a national scale is limited. In this study, we conducted a review of 190 articles about soil Cd concentrations during 2001 to 2010. The study involved 146 cities in China, and we quantified the risks to human health according to different regions. The results showed that elevated Cd levels were present compared to the background value of soil in 1990, and the soil Cd concentrations in the Guangxi province exceeded even the class III Soil Environmental Quality standard, which is the limit for the normal growth of plants. The Chinese soil Cd concentrations ranged from 0.003 mg kg(-1) to 9.57 mg kg(-1). The soil Cd concentrations had the following trend: northwest > southwest > south central > east > northeast > north. The sources of soil Cd are mainly from smelting, mining, waste disposal, fertilizer and pesticide application, and vehicle exhaust, etc. but differentiated in various regions. The soil Cd contamination in urban areas was more serious than contamination in the agricultural areas. Currently, there is no significant non-carcinogenic risk in any of the provinces. Regarding the different exposure pathways, the dermal pathway is the primary source of soil Cd exposure, and the risk associated with this pathway is generally hundreds of times higher than the risk for an ingestion pathway. For most of the provinces, the health risk to the urban population was higher than the risk to the rural population. For each population, the carcinogenic risk was less than 10(-6) in most of the provinces, except for the urban population in the Hunan province. If the other exposure pathways are fully considered, then the people in these areas may have a higher carcinogenic risk. This

  12. Assessment of the human health risks posed by exposure to chromium-contaminated soils

    SciTech Connect

    Sheehan, P.J.; Meyer, D.M.; Sauer, M.M.; Paustenbach, D.J. )

    1991-02-01

    Millions of tons of chromite-ore processing residue have been used as fill in various locations in northern New Jersey and elsewhere in the United States. The primary toxicants in the residue are trivalent chromium (Cr(III)) and hexavalent chromium (Cr(VI)). The hazard posed by Cr(III) is negligible due to its low acute and chronic toxicity. In contrast, Cr(VI) is a human carcinogen following inhalation of high concentrations. It can also cause allergic contact dermatitis. This evaluation addresses a residential site where the arithmetic mean (x) and geometric mean (gm) concentrations of Cr(III) in soil were 2879 and 1212 mg/kg (ppm). The mean concentrations of Cr(VI) were 180 and 4 mg/kg, respectively. The uptake (absorbed dose) of Cr(III) via soil ingestion, consumption of homegrown vegetables, and ingestion of inspired particles was determined. The uptake of Cr(VI) via dermal absorption from contact with surface soil and building wall surfaces, as well as inhalation, was also evaluated. The techniques used in this assessment are applicable for evaluating the human health risks posed by any residential site having contaminated soil. The potential for both sensitized and unsensitized persons to develop allergic contact dermatitis due to exposure to soil contaminated at these levels was found to be negligible. The estimated average daily dose (ADD) via ingestion and dermal absorption for the maximally exposed individual (MEI) was about 1500- and 40-fold below the EPA reference dose (RfD) for Cr(III) and Cr(VI), respectively. It was shown that for residential sites, the most important route of exposure to Cr(III) was incidental soil ingestion. Although not relevant to these sites specifically, if garden vegetables could be successfully grown in these soils, then they would probably be the predominant source of uptake of Cr(III). 163 refs.

  13. Assessing contaminant sensitivity of endangered and threatened aquatic species: Part I. Acute toxicity of five chemicals

    USGS Publications Warehouse

    Dwyer, F.J.; Mayer, F.L.; Sappington, L.C.; Buckler, D.R.; Bridges, C.M.; Greer, I.E.; Hardesty, D.K.; Henke, C.E.; Ingersoll, C.G.; Kunz, J.L.; Whites, D.W.; Augspurger, T.; Mount, D.R.; Hattala, K.; Neuderfer, G.N.

    2005-01-01

    Assessment of contaminant impacts to federally identified endangered, threatened and candidate, and state-identified endangered species (collectively referred to as "listed" species) requires understanding of a species' sensitivities to particular chemicals. The most direct approach would be to determine the sensitivity of a listed species to a particular contaminant or perturbation. An indirect approach for aquatic species would be application of toxicity data obtained from standard test procedures and species commonly used in laboratory toxicity tests. Common test species (fathead minnow, Pimephales promelas; sheepshead minnow, Cyprinodon variegatus; and rainbow trout, Oncorhynchus mykiss) and 17 listed or closely related species were tested in acute 96-hour water exposures with five chemicals (carbaryl, copper, 4-nonylphenol, pentachlorophenol, and permethrin) representing a broad range of toxic modes of action. No single species was the most sensitive to all chemicals. For the three standard test species evaluated, the rainbow trout was more sensitive than either the fathead minnow or sheepshead minnow and was equal to or more sensitive than listed and related species 81% of the time. To estimate an LC50 for a listed species, a factor of 0.63 can be applied to the geometric mean LC50 of rainbow trout toxicity data, and more conservative factors can be determined using variance estimates (0.46 based on 1 SD of the mean and 0.33 based on 2 SD of the mean). Additionally, a low- or no-acute effect concentration can be estimated by multiplying the respective LC50 by a factor of approximately 0.56, which supports the United States Environmental Protection Agency approach of multiplying the final acute value by 0.5 (division by 2). When captive or locally abundant populations of listed fish are available, consideration should be given to direct testing. When direct toxicity testing cannot be performed, approaches for developing protective measures using common test

  14. Assessing aquifer contamination risk using immunoassay: trace analysis of atrazine in unsaturated zone sediments

    USGS Publications Warehouse

    Juracek, K.E.; Thurman, E.M.

    1997-01-01

    The vulnerability of a shallow aquifer in south-central Kansas to contamination by atrazine (2-chloro-4-ethylamino-6-isopropylamines-triazine) was assessed by analyzing unsaturated zone soil and sediment samples from about 60 dryland and irrigated sites using an ultrasensitive immunoassay (detection level of 0.02 µg/kg) with verification by gas chromatography/mass spectrometry (GC/MS). Samples were collected at depths of 0 to 1.2 m (i.e., the root zone), 1.2 to 1.8 m, and 1.8 to 3.0 m during two time periods-prior to planting and after harvest of crops. About 75% of the samples contained detectable concentrations of parent atrazine. At the shallow sampling depth, atrazine concentrations ranged from 0.5 to approximately 12 µg/kg. Atrazine concentrations at the intermediate (1.2-1.8 m) depth generally were <1.0 µg/kg, with most of the concentrations <0.10 µg/kg, which suggests substantial degradation of parent atrazine in the root zone. Likewise, atrazine concentrations front the deepest (1.8-3.0 m) depth ranged from <0.02 to 0.33 µg/kg. The metabolite deethylatrazine (2-amino-4-chloro-6- isopropylamine-s-triazine) was detected by GC/MS only in 2 of 60 samples with concentrations of 1.4 and 1.5 µg/kg. The reconnaissance survey shows that, in spite of atrazine use ranging from 1 to 5 or more years, there does not appear to he a significant buildup of parent compound below the root zone. Therefore, the unsaturated zone does not appear to be a major storage compartment of atrazine contamination for the underlying shallow aquifer.

  15. Assessment of nitrate-N contamination in the Chunnakam aquifer system, Jaffna Peninsula, Sri Lanka.

    PubMed

    Vithanage, Meththika; Mikunthan, Thushyanthi; Pathmarajah, Selverajah; Arasalingam, Sutharsiny; Manthrithilake, Herath

    2014-01-01

    Jaffna peninsula in Sri Lanka is an area of intensive agriculture using extensive organic and inorganic nitrogenous compounds and hence, this study was focused on assessing vulnerability of karstic aquifer system with specific focus on nitrate contamination, and compare loads of nitrate from agriculture. The total number of the wells sampled in the Chunnakam aquifer is 44. The coverage of wells with measurements of nitrate and nitrite concentrations in the database covering the study period from Januray, 2011 to August, 2011. The intrinsic vulnerability of the area is estimated by the DRASTIC model and the modified DRASTIC method was used to determine the nitrate-specific vulnerability of the aquifers. Average concentrations of nitrate-N and nitrite-N during the study period were 4.869 and 0.014 mg/L respectively. The average number of wells exceeding permissible level of NO3-N is approximately 6-12, which means that about 14-28% out of the 44 wells. Modified DRASTIC (DI) index value computed as explained above increased from DI = 177 to a range of 182 to 197. In spite of the increase, the Modified DI values show that the aquifer vulnerability specific to nitrate contamination remains in "high" category. Although nitrogen loading at the domestic sources and irrigation is of the same order of magnitude, the loading from fertilizer input is much larger which is about 15 times higher. This finding suggests that the fertilizer input in agricultural areas constitute a significant contribution to the nitrogen content in the groundwater and soils in agricultural areas of Jaffna. PMID:24944879

  16. 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...

  17. Evaluation of chemical, molecular, and traditional markers of fecal contamination in an effluent dominated urban stream.

    PubMed

    Litton, Rachel M; Ahn, Jong Ho; Sercu, Bram; Holden, Patricia A; Sedlak, David L; Grant, Stanley B

    2010-10-01

    In this paper we present a quantitative sanitary survey of the Middle Santa Ana River, in southern California, utilizing a variety of source tracking tools, including traditional culture-dependent fecal markers (Enterococcus and Escherichia coli by IDEXX), speciation of enterococci isolates, culture-independent fecal markers (human-specific HF183 Bacteroides and Enterococcus by quantitative polymerase chain reaction, qPCR), and chemical markers of sewage and wastewater (nutrients, enantiomeric fraction (EF) of propranolol and ethylenediaminetetraacetic acid). To facilitate comparison of these different methods, data are interpreted in a loading (i.e., mass per time) framework that enables a quantitative apportionment of fecal markers and nutrients to specific source waters in the Middle Santa Ana River. Multiple lines of evidence support the hypothesis that Enterococcus in the Middle Santa Ana River originates primarily from in situ growth in streambed sediments, not from significant and persistent sources of untreated human waste. The EF of propranolol of tertiary treated wastewater effluent is in the range (0.42 to 0.71) previously reported for raw sewage, making EF of propranolol an unsuitable marker for fecal pollution, at least at this site. The human fecal marker HF183 Bacteroides was detected at a few sites, although not in a source of disinfected and tertiary treated wastewater effluent. Based on the results presented here and prior experience at other sites in southern California, HF183 Bacteroides would appear to be a candidate marker of fecal contamination for inland waters, although more qPCR measurements in disinfected wastewater effluent are needed to account for variations due to treatment plant performance and other factors. More generally, our results support the notion that regrowth of fecal indicator bacteria (FIB) in river sediments may lead to a decoupling between FIB and pathogen concentrations in the water column and thus limit the utility of

  18. Molecular characterization of Escherichia coli O157:H7 hide contamination routes: feedlot to harvest.

    PubMed

    Childs, K D; Simpson, C A; Warren-Serna, W; Bellenger, G; Centrella, B; Bowling, R A; Ruby, J; Stefanek, J; Vote, D J; Choat, T; Scanga, J A; Sofos, J N; Smith, G C; Belk, K E

    2006-06-01

    This study was conducted to identify the origin of Escherichia coli O157:H7 contamination on steer hides at the time of harvest. Samples were collected from the feedlot, transport trailers, and packing plant holding pens and from the colons and hides of feedlot steers. A total of 50 hide samples were positive for E. coli O157:H7 in two geographical locations: the Midwest (25 positive hides) and Southwest (25 positive hides). Hide samples were screened, and the presence of E. coli O157: H7 was confirmed. E. coli O157:H7 isolates were fingerprinted by pulsed-field gel electrophoresis and subjected to multiplex PCR procedures for amplification of E. coli O157:H7 genes stx1, stx2, eaeA, fliC, rfbEO157, and hlyA. Feedlot water trough, pen floor, feed bunk, loading chute, truck trailer side wall and floor, packing plant holding pen floor and side rail, and packing plant cattle drinking water samples were positive for E. coli O157:H7. Pulsed-field gel electrophoresis banding patterns were analyzed after classifying isolates according to the marker genes present and according to packing plant. In this study, hide samples positive for E. coli O157:H7 were traced to other E. coli O157:H7-positive hide, colon, feedlot pen floor fecal, packing plant holding pen drinking water, and transport trailer side wall samples. Links were found between packing plant side rails, feedlot loading chutes, and feedlot pens and between truck trailer, different feedlots, and colons of multiple cattle. This study is the first in which genotypic matches have been made between E. coli O157:H7 isolates obtained from transport trailer side walls and those from cattle hide samples within the packing plant. PMID:16786841

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

    SciTech Connect

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

    2015-04-15

    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. - 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.

  20. 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...

  1. Assessing Nation-wide Distributions of Contaminant Levels in Selected Finfish and Shellfish from the Estuaries of the United States

    EPA Science Inventory

    The toxicity of mercury is well documented and has led to laws and regulations governing its use and disposal; however mercury contamination of coastal and estuarine biota continues to be of public concern. The U.S. EPA Environmental Monitoring and Assessment Program provided da...

  2. Environmental assessment on electrokinetic remediation of multimetal-contaminated site: a case study.

    PubMed

    Kim, Do-Hyung; Yoo, Jong-Chan; Hwang, Bo-Ram; Yang, Jung-Seok; Baek, Kitae

    2014-05-01

    In this study, an environmental assessment on an electrokinetic (EK) system for the remediation of a multimetal-contaminated real site was conducted using a green and sustainable remediation (GSR) tool. The entire EK process was classified into major four phases consisting of remedial investigations (RIs), remedial action construction (RAC), remedial action operation (RAO), and long-term monitoring (LTM) for environmental assessment. The environmental footprints, including greenhouse gas (GHG) emissions, total energy used, air emissions of criteria pollutants, such as NOx, SOx, and PM10, and water consumption, were calculated, and the relative contribution in each phase was analyzed in the environmental assessment. In the RAC phase, the relative contribution of the GHG emissions, total energy used, and PM10 emissions were 77.3, 67.6, and 70.4%, respectively, which were higher than those of the other phases because the material consumption and equipment used for system construction were high. In the RAO phase, the relative contributions of water consumption and NOx and SOx emissions were 94.7, 85.2, and 91.0%, respectively, which were higher than those of the other phases, because the water and electricity consumption required for system operation was high. In the RIs and LTM phases, the environmental footprints were negligible because the material and energy consumption was less. In conclusion, the consumable materials and electrical energy consumption might be very important for GSR in the EK remediation process, because the production of consumable materials and electrical energy consumption highly affects the GHG emissions, total energy used, and air emissions such as NOx and SOx. PMID:24515871

  3. Alternative Methods for Assessing Contaminant Transport from the Vadose Zone to Indoor Air

    NASA Astrophysics Data System (ADS)

    Baylor, K. J.; Lee, A.; Reddy, P.; Plate, M.

    2010-12-01

    Vapor intrusion, which is the transport of contaminant vapors from groundwater and the vadose zone to indoor air, has emerged as a significant human health risk near hazardous waste sites. Volatile organic compounds (VOCs) such as trichloroethylene (TCE) and tetrachloroethylene (PCE) can volatilize from groundwater and from residual sources in the vadose zone and enter homes and commercial buildings through cracks in the slab, plumbing conduits, or other preferential pathways. Assessment of the vapor intrusion pathway typically requires collection of groundwater, soil gas, and indoor air samples, a process which can be expensive and time-consuming. We evaluated three alternative vapor intrusion assessment methods, including 1) use of radon as a surrogate for vapor intrusion, 2) use of pressure differential measurements between indoor/outdoor and indoor/subslab to assess the potential for vapor intrusion, and 3) use of passive, longer-duration sorbent methods to measure indoor air VOC concentrations. The primary test site, located approximately 30 miles south of San Francisco, was selected due to the presence of TCE (10 - 300 ug/L) in shallow groundwater (5 to 10 feet bgs). At this test site, we found that radon was not a suitable surrogate to asses vapor intrusion and that pressure differential measurements are challenging to implement and equipment-intensive. More significantly, we found that the passive, longer-duration sorbent methods are easy to deploy and compared well quantitatively with standard indoor air sampling methods. The sorbent technique is less than half the cost of typical indoor air methods, and also provides a longer duration sample, typically 3 to 14 days rather than 8 to 24 hours for standard methods. The passive sorbent methods can be a reliable, cost-effective, and easy way to sample for TCE, PCE and other VOCs as part of a vapor intrusion investigation.

  4. PCB contamination from polysulphide sealants in residential areas-exposure and risk assessment.

    PubMed

    Priha, Eero; Hellman, Sannamari; Sorvari, Jaana

    2005-04-01

    From the late 1950s to the early 1970s elastic polysulphide sealants were used in outdoor seams between concrete blocks in prefabricated buildings. The sealants contained 5-30% polychlorinated biphenyls (PCBs). Due to the weathering of sealants in general and the replacement of seams with new PCB-free materials in the 1990s, PCBs have drifted to the soil adjacent to buildings. The objectives of this study were to survey PCB contamination in the surroundings of former PCB-containing buildings and to evaluate the risks to human health. Samples from soil, and also from blood serum of residents, were collected to obtain data for exposure assessment. The health risk assessment was based on deterministic and probabilistic calculations for cancer and non-cancer risks. Soil ingestion and dermal contact were considered the main routes of exposure and children the most important exposed group. The mean total PCB concentration was 6.83 mg/kg within 2m of the buildings and 0.52 mg/kg within 3-10 m from of the buildings. The deterministic risk assessment with conservative parameters resulted in lifetime cancer risk estimates on the order of 10(-6)-10(-7). The lifetime average daily dose (LADD) for PCBs was less than 10% of the reference dose (RfD) 0.02 microg/kg day, which is based on immunosupression in monkeys. The LADD corresponding to the total site attributable exposure was less than 10% of the estimated average dietary PCB intake in Finland. Children can, however, in worst cases be exposed to daily doses near the level of the RfD. Low cost measures are recommended to reduce possible exposure of children. PMID:15788176

  5. 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...

  6. Understanding star formation in molecular clouds. I. Effects of line-of-sight contamination on the column density structure

    NASA Astrophysics Data System (ADS)

    Schneider, N.; Ossenkopf, V.; Csengeri, T.; Klessen, R. S.; Federrath, C.; Tremblin, P.; Girichidis, P.; Bontemps, S.; André, Ph.

    2015-03-01

    Column-density maps of molecular clouds are one of the most important observables in the context of molecular cloud- and star-formation (SF) studies. With the Herschel satellite it is now possible to precisely determine the column density from dust emission, which is the best tracer of the bulk of material in molecular clouds. However, line-of-sight (LOS) contamination from fore- or background clouds can lead to overestimating the dust emission of molecular clouds, in particular for distant clouds. This implies values that are too high for column density and mass, which can potentially lead to an incorrect physical interpretation of the column density probability distribution function (PDF). In this paper, we use observations and simulations to demonstrate how LOS contamination affects the PDF. We apply a first-order approximation (removing a constant level) to the molecular clouds of Auriga and Maddalena (low-mass star-forming), and Carina and NGC 3603 (both high-mass SF regions). In perfect agreement with the simulations, we find that the PDFs become broader, the peak shifts to lower column densities, and the power-law tail of the PDF for higher column densities flattens after correction. All corrected PDFs have a lognormal part for low column densities with a peak at Av ~ 2 mag, a deviation point (DP) from the lognormal at Av(DP) ~ 4-5 mag, and a power-law tail for higher column densities. Assuming an equivalent spherical density distribution ρ ∝ r- α, the slopes of the power-law tails correspond to αPDF = 1.8, 1.75, and 2.5 for Auriga, Carina, and NGC 3603. These numbers agree within the uncertainties with the values of α ≈ 1.5,1.8, and 2.5 determined from the slope γ (with α = 1-γ) obtained from the radial column density profiles (N ∝ rγ). While α ~ 1.5-2 is consistent with a structure dominated by collapse (local free-fall collapse of individual cores and clumps and global collapse), the higher value of α > 2 for NGC 3603 requires a physical

  7. 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

  8. Tissue Microarray Technology for Molecular Applications: Investigation of Cross-Contamination between Tissue Samples Obtained from the Same Punching Device

    PubMed Central

    Vassella, Erik; Galván, José A.; Zlobec, Inti

    2015-01-01

    Background: Tissue microarray (TMA) technology allows rapid visualization of molecular markers by immunohistochemistry and in situ hybridization. In addition, TMA instrumentation has the potential to assist in other applications: punches taken from donor blocks can be placed directly into tubes and used for nucleic acid analysis by PCR approaches. However, the question of possible cross-contamination between samples punched with the same device has frequently been raised but never addressed. Methods: Two experiments were performed. (1) A block from mycobacterium tuberculosis (TB) positivetissue and a second from an uninfected patient were aligned side-by-side in an automated tissue microarrayer. Four 0.6 mm punches were cored from each sample and placed inside their corresponding tube. Between coring of each donor block, a mechanical cleaning step was performed by insertion of the puncher into a paraffin block. This sequence of coring and cleaning was repeated three times, alternating between positive and negative blocks. A fragment from the 6110 insertion sequence specific for mycobacterium tuberculosis was analyzed; (2) Four 0.6 mm punches were cored from three KRAS mutated colorectal cancer blocks, alternating with three different wild-type tissues using the same TMA instrument (sequence of coring: G12D, WT, G12V, WT, G13D and WT). Mechanical cleaning of the device between each donor block was made. Mutation analysis by pyrosequencing was carried out. This sequence of coring was repeated manually without any cleaning step between blocks. Results/Discussion: In both analyses, all alternating samples showed the expected result (samples 1, 3 and 5: positive or mutated, samples 2, 4 and 6: negative or wild-type). Similar results were obtained without cleaning step. These findings suggest that no cross-contamination of tissue samples occurs when donor blocks are punched using the same device, however a cleaning step is nonetheless recommended. Our result supports

  9. Assessment of mobility and bioavailability of contaminants in MSW incineration ash with aquatic and terrestrial bioassays.

    PubMed

    Ribé, V; Nehrenheim, E; Odlare, M

    2014-10-01

    Incineration of municipal solid waste (MSW) is a waste treatment method which can be sustainable in terms of waste volume reduction as well as a source of renewable energy. In the process fly and bottom ash is generated as a waste material. The ash residue may vary greatly in composition depending on the type of waste incinerated and it can contain elevated levels of harmful contaminants such as heavy metals. In this study, the ecotoxicity of a weathered, untreated incineration bottom ash was characterized as defined by the H14 criterion of the EU Waste Framework Directive by means of an elemental analysis, leaching tests followed by a chemical analysis and a combination of aquatic and solid-phase bioassays. The experiments were conducted to assess the mobility and bioavailability of ash contaminants. A combination of aquatic and terrestrial bioassays was used to determine potentially adverse acute effects of exposure to the solid ash and aqueous ash leachates. The results from the study showed that the bottom ash from a municipal waste incineration plant in mid-Sweden contained levels of metals such as Cu, Pb and Zn, which exceeded the Swedish EPA limit values for inert wastes. The chemical analysis of the ash leachates showed high concentrations of particularly Cr. The leachate concentration of Cr exceeded the limit value for L/S 10 leaching for inert wastes. Filtration of leachates prior to analysis may have underestimated the leachability of complex-forming metals such as Cu and Pb. The germination test of solid ash and ash leachates using T. repens showed a higher inhibition of seedling emergence of seeds exposed to the solid ash than the seeds exposed to ash leachates. This indicated a relatively low mobility of toxicants from the solid ash into the leachates, although some metals exceeded the L/S 10 leaching limit values for inert wastes. The Microtox® toxicity test showed only a very low toxic response to the ash leachate exposure, while the D. magna

  10. Selective removal of diclofenac from contaminated water using molecularly imprinted polymer microspheres.

    PubMed

    Dai, Chao-Meng; Geissen, Sven-Uwe; Zhang, Ya-Lei; Zhang, Yong-Jun; Zhou, Xue-Fei

    2011-06-01

    A molecularly imprinted polymer (MIP) was synthesized by precipitation polymerization using diclofenac (DFC) as a template. Binding characteristics of the MIP were evaluated using equilibrium binding experiments. Compared to the non-imprinted polymer (NIP), the MIP showed an outstanding affinity towards DFC in an aqueous solution with a binding site capacity (Q(max)) of 324.8 mg/g and a dissociation constant (K(d)) of 3.99 mg/L. The feasibility of removing DFC from natural water by the MIP was demonstrated by using river water spiked with DFC. Effects of pH and humic acid on the selectivity and adsorption capacity of MIP were evaluated in detail. MIP had better selectivity and higher adsorption efficiency for DFC as compared to that of powdered activated carbon (PAC). In addition, MIP reusability was demonstrated for at least 12 repeated cycles without significant loss in performance, which is a definite advantage over single-use activated carbon. PMID:21439696

  11. Molecular characterization of Aspergillus flavus and aflatoxin contamination of wheat grains from Saudi Arabia.

    PubMed

    Al-Wadai, A S; Al-Othman, M R; Mahmoud, M A; Abd El-Aziz, A R M

    2013-01-01

    Twelve species belonging to six fungal genera were found to be associated with wheat (Triticum aestivum L.) grain samples collected from three main regions in Saudi Arabia. The most common genera (average frequency) were Aspergillus (14.3%), Fusarium (29.1%), Penicillium (9.3%), and Alternaria (8.2%). Nineteen isolates of Aspergillus flavus were screened for their ability to produce aflatoxins using HPLC. Thirteen isolates produced aflatoxins ranging from 0.5 to 2.6 µg/kg. Inter-simple sequence repeats (ISSR), and random amplified polymorphic DNA (RAPD) molecular markers were used, with the aim of genetically characterizing strains of A. flavus to discriminate between aflatoxigenic and non-aflatoxigenic isolates. RAPD and ISSR analysis revealed a high level of genetic diversity in the A. flavus population, useful for genetic characterization. Clustering based on RAPD and ISSR dendograms was unrelated to geographic origin. RAPD and ISSR markers were not suitable to discriminate aflatoxigenic and non-aflatoxigenic isolates, but ISSR primers were better compared to RAPD. PMID:24065675

  12. Baseline risk assessment of ground water contamination at the Uranium Mill Tailings Site near Green River, Utah. Revision 1

    SciTech Connect

    1995-09-01

    The Uranium Mill Tailings Remedial Action (UMTRA) Project consists of the Surface Project (phase 1) and the Ground Water Project (phase 2). For the UMTRA Project site located near Green River, Utah, the Surface Project cleanup occurred from 1988 to 1989. The tailings and radioactively contaminated soils and materials were removed from their original locations and placed into a disposal cell on the site. The disposal cell is designed to minimize radiation emissions and minimize further contamination of ground water beneath the site. The UMTRA Project`s second phase, the Ground Water Project, evaluates the nature and extent of ground water contamination resulting from uranium processing and determines a strategy for ground water compliance with the Environmental Protection Agency (EPA) ground water standards established for the UMTRA Project. For the Green River site, the risk assessment helps determine whether human health risks result from exposure to ground water contaminated by uranium processing. This risk assessment report is the first site-specific document prepared for the UMTRA Ground Water Project at the Green River site. What follows is an evaluation of current and possible future impacts to the public and the environment from exposure to contaminated ground water. The results of this evaluation and further site characterization will be used to determine what is necessary, if anything, to protect human health and the environment while complying with EPA standards.

  13. 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.

  14. Baseline risk assessment of ground water contamination at the Uranium Mill Tailings Site near Naturita, Colorado. Revision 1

    SciTech Connect

    1995-11-01

    The Uranium Mill Tailings Remedial Action (UMTRA) Project consists of the Surface Project, and the Ground Water Project. For the UMTRA Project site located near Naturita, Colorado, phase I involves the removal of radioactively contaminated soils and materials and their transportation to a disposal site at Union Carbide Corporation`s Upper Burbank Repository at Uravan, Colorado. The surface cleanup will reduce radon and other radiation emissions from the former uranium processing site and prevent further site-related contamination of ground water. Phase II of the project will evaluate the nature and extent of ground water contamination resulting from uranium processing and its effect on human health and the environment, and will determine site-specific ground water compliance strategies in accordance with the US Environmental Protection Agency (EPA) ground water standards established for the UMTRA Project. Human health risks could occur from drinking water pumped from a hypothetical well drilled in the contaminated ground water area. Environmental risks may result if plants or animals are exposed to contaminated ground water or surface water that has mixed with contaminated ground water. Therefore, a risk assessment was conducted for the Naturita site. This risk assessment report is the first site-specific document prepared for the Ground Water Project at the Naturita site. What follows is an evaluation of current and possible future impacts to the public and the environment from exposure to contaminated ground water. The results of this evaluation and further site characterization will be used to determine whether any action is needed to protect human health or the environment.

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

    NASA Astrophysics Data System (ADS)

    Breshears, David D.; Kirchner, Thomas B.; Whicker, Jeffrey J.; Field, Jason 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.

  16. 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, C.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