Download or read book Measurement and Modeling of Polychlorinated Biphenyl Availability from Contaminated Sediment and Evaluation of Ecosystem Recovery written by Elisabeth Marie-Louise Janssen and published by Stanford University. This book was released on 2010 with total page 163 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research comprises measurement and modeling of polychlorinated biphenyl (PCB) bioaccumulation from contaminated sediments and the evaluation of an in-situ sorbent amendment with activated carbon (AC) to allow ecosystem recovery. Laboratory bioassays with the deposit feeding polychaete Neanthes arenaceodentata, showed that PCB uptake from the aqueous phase accounted for less than three percent of the total uptake. High sediment ingestion rates and fast bioaccumulation of PCBs exceeding sediment concentration within 14 days of exposure suggest that deposit feeders are promising test organisms to evaluate local sediment conditions. A biodynamic model that described bioaccumulation by a mass balance approach of contaminant influx and efflux was parameterized for this polychaete. The model allows the prediction of tissue concentrations and facilitates the understanding of exposure pathways. Subsequently, the effects of an AC-amendment to sediment from a PCB-contaminated site at Hunters Point within the San Francisco Bay, California, were evaluated by employing caged deposit-feeders, along with polyoxymethylene (POM) samplers using parallel in situ and ex situ bioassays with homogenized untreated or AC-amended sediment. The AC-amendment reduced bioaccumulation by 90% in the laboratory and by 44% in parallel field tests with treated and untreated sediment. In-situ measurements with passive pore water samplers showed that PCB uptake was greater for samplers placed in the surface sediment compared to the underlying AC-amendment. The tests revealed three factors that influenced the in-situ bioassays: 1. AC-amendment significantly reduces bioavailability under laboratory and field conditions; 2. Deposit-feeding organisms exhibit less PCB uptake from untreated sediment when feeding is reduced; and 3. Sediment deposition within test cages in the field partially masks the benefit of underlying AC-amended sediment and emphasizes the need of area-wide considerations when assessing contaminated sediment management and remediation strategies. Parallel ex-situ and in-situ bioassays in combination with passive sampler measurements can tease apart field influences on PCB exposure. These tests should accompany each other to evaluate in-situ exposure and the effectiveness of remediation alternatives. This research further focused on pollution-induced changes of the benthic community at Hunters Point and the evaluation of the expected recovery potential after an AC-amendment for in-situ sediment remediation. The benthic community composition was compared for the PCB-contaminated site at Hunters Point and 30 reference sites in the San Francisco Bay to evaluate pollution-induced changes. Given the similar number of species, total abundance, and diversity indices between the reference sites and Hunters Point, it could be concluded that the benthic communities did not differ greatly. However, further analysis based on functional traits of the benthic community shows that the community at Hunters Point is deprived of species that may be stressed by the contaminated sediment due to their feeding mode, reproductive mode, or position in the sediment. The benthic community in comparison to reference sites lacks deposit feeders, subsurface carnivores, egg laying species, and species with no/weak protective barrier. Sediment chemistry analysis shows that PCBs are the major risk drivers at Hunters Point and that the reference sites show only ambient levels of PCB contamination. Biodynamic modeling demonstrates how varying exposure and functional feeding strategies affect PCB bioaccumulation, with a deposit feeder accumulating two orders of magnitude more PCBs in its lipids than a facultative deposit feeder and up to three orders of magnitude more than a filter feeder. Modeling scenarios also show that PCB tissue concentrations at Hunters Point are two orders of magnitude higher than at the reference sites. Sediment remediation with a sorbent (activated carbon) amendment at Hunters Point can reduce PCB availability by 85 to 90% under favorable field and treatment conditions. The expected remedial success corresponds to exposure conditions within sediment quality guidelines and the cleanup goal but remains slightly higher than at the reference sites.

Download or read book Sediment quality and polychlorinated biphenyls in the lower Neponset River Massachusetts and implications for urban river restoration written by and published by DIANE Publishing. This book was released on with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Risk Management Strategy for PCB Contaminated Sediments written by National Research Council and published by National Academies Press. This book was released on 2001-06-07 with total page 451 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a risk-based framework for developing and implementing strategies to manage PCB-contaminated sediments at sites around the country. The framework has seven stages, beginning with problem definition, continuing through assessment of risks and management options, and ending with an evaluation of the success of the management strategy. At the center of the framework is continuous and active involvement of all affected parties-particularly communities-in the development, implementation, and evaluation of the management strategy. A Risk-Management Strategy for PCB-Contaminated Sediments emphasizes the need to consider all risks at a contaminated site, not just human health and ecological effects, but also the social, cultural, and economic impacts. Given the controversy that has arisen at many PCB-contaminated sites, this book provides a consistent, yet flexible, approach for dealing with the many issues associated with assessing and managing the risks at Superfund and other contaminated sites.

Download or read book Proceedings of the Expert Panel Workshop to Evaluate the Public Health Implications of the Treatment and Disposal of Polychlorinated Biphenyls contaminated Waste written by Maureen Y. Lichtveld and published by . This book was released on 1994 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Polychlorinated Biphenyl PCB Contaminated Sediment in the Lower Fox River written by and published by . This book was released on 1997 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Departments of Veterans Affairs and Housing and Urban Development and Independent Agencies Appropriations for 2004 written by United States. Congress. House. Committee on Appropriations. Subcommittee on VA, HUD, and Independent Agencies and published by . This book was released on 2003 with total page 1486 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book 108 1 Hearings Departments of Veterans Affairs and Housing and Urban Development and Independent Agencies Appropriations For 2004 Part 3 April 2 2003 written by and published by . This book was released on 2003 with total page 1450 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Selected Water Resources Abstracts written by and published by . This book was released on 1991 with total page 962 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Human and Ecological Risk Assessment written by Dennis J. Paustenbach and published by John Wiley & Sons. This book was released on 2024-04-23 with total page 1319 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understand the fundamentals of human risk assessment with this introduction and reference Human risk assessments are a precondition for virtually all industrial action or environmental regulation, all the more essential in a world where chemical and environmental hazards are becoming more abundant. These documents catalog potential environmental, toxicological, ecological, or other harms resulting from a particular hazard, from chemical spills to construction projects to dangerous workplaces. They turn on a number of variables, of which the most significant is the degree of human exposure to the hazardous agent or process. Human and Ecological Risk Assessment combines the virtues of a textbook and reference work to introduce and analyze these vital documents. Beginning with the foundational theory of human health risk assessment, it then supplies case studies and detailed analysis illustrating the practice of producing risk assessment documents. Fully updated and authored by leading authorities in the field, the result is an indispensable work. Readers of the second edition of Human and Ecological Risk Assessment will also find: Over 40 entirely new case studies reflecting the latest in risk assessment practice Detailed discussion of hazards including air emissions, contaminated food and soil, hazardous waste sites, and many more Case studies from multiple countries to reflect diverse international standards Human and Ecological Risk Assessment is ideal for professionals and advanced graduate students in toxicology, industrial hygiene, occupational medicine, environmental science, and all related subjects.

Download or read book Determination of Polychlorinated Biphenyls PCBs in Sediment and Biota written by Lynda Webster and published by . This book was released on 2013 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book BIOACCUMULATION OF POLYCHLORINATED BIPHENYL COMPOUNDS AND MERCURY IN A MINING IMPACTED AQUATIC ECOSYSTEM written by and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract : The Keweenaw area continues to be influenced by the century of copper mining that ended nearly 50 years ago. This project is focused on Torch Lake, an aquatic ecosystem that has been heavily impacted by mining waste disposal. The watershed has been impaired by mine discharge and tailings, smelter and smokestack plumes, and poor waste disposal practices. The lake is listed as a Great Lakes Area of Concern with beneficial use impairments of restrictions on fish consumption and a degraded benthic community. Polychlorinated biphenyl compounds (PCBs) and methylmercury (MeHg) are persistent, bioaccumulative, and toxic substances (PBTs). These contaminants pose threats to human and environmental health primarily via fish consumption. The use impairment of restricted fish consumption is a result of elevated concentrations of PCBs and MeHg in Torch Lake. In this research, kinetic bioaccumulation models were developed using MATLAB to estimate steady state concentrations in each trophic level of the Torch Lake food chain. The model links the contaminated environment to the bioaccumulation in a single organism. The model is most sensitive to the dietary uptake rate constants, and Monte Carlo simulations indicate that the uncertainty (95% confidence interval) is approximately 0.13 ng/g ww for PCBs and 0.02 mg/g ww for MeHg. Model-predicted concentrations agree with the steady-state model, AQUAWEB, and with concentrations measured in walleye (Sander vitreus). The kinetic model coupled with a mass balance model is used to predict the extent of recovery of the ecosystem following remediation actions, such as removal of local contaminant sources to the lake. Removal of contaminated sediments is predicted to reduce the PCB congener concentrations by a factor of 2-14, and elimination of in-lake methylation was predicted to reduce fish Hg concentrations by a factor of 2. Thus, the model suggests that the planned remediation under the Legacy Act will significantly reduce PCB concentrations in fish. The model indicates that adult fish entering Torch Lake from the Keweenaw Waterway could reach the observed PCB contaminant concentrations in fish within 62 days to over 10 years, but other studies have indicated that immigration of fish to Torch Lake is uncommon.

Download or read book Bioavailability of Contaminants in Soils and Sediments written by National Research Council and published by National Academies Press. This book was released on 2003-05-03 with total page 433 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bioavailability refers to the extent to which humans and ecological receptors are exposed to contaminants in soil or sediment. The concept of bioavailability has recently piqued the interest of the hazardous waste industry as an important consideration in deciding how much waste to clean up. The rationale is that if contaminants in soil and sediment are not bioavailable, then more contaminant mass can be left in place without creating additional risk. A new NRC report notes that the potential for the consideration of bioavailability to influence decision-making is greatest where certain chemical, environmental, and regulatory factors align. The current use of bioavailability in risk assessment and hazardous waste cleanup regulations is demystified, and acceptable tools and models for bioavailability assessment are discussed and ranked according to seven criteria. Finally, the intimate link between bioavailability and bioremediation is explored. The report concludes with suggestions for moving bioavailability forward in the regulatory arena for both soil and sediment cleanup.

Download or read book Characterizing Polychlorinated Biphenyl Exposure in Aquatic and Riparian Species of Campus Lake written by Megan Archer and published by . This book was released on 2015 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: Estimating the risk of polychlorinated biphenyls (PCBs) in aquatic systems requires evaluation of exposure, usually based on exhaustive chemical extraction of sediment and potentially exposed organisms and an assessment of toxicity. Remediation can then focus on areas where the exposure leads to the highest risk. Although effective, an approach that estimates exposure, which accounts for bioavailabilty, bioaccumulation, trophic transfer potential, and transport of materials within and out of the waterway, should serve as a more comprehensive environmental assessment. The current study examined exposure of PCBs in several different trophic levels within the Campus Lake ecosystem, Carbondale, Illinois. The source of contamination and the distribution of PCBs among ecosystem components demonstrated contamination within the aquatic portion of Campus Lake and transport out of the aquatic environment to the riparian area. Several media were collected including sediment, emergent insects, spiders, and three species of fish. Sediment extractions demonstrated that PCBs were localized to one small cove and this area served as the source for transfer of PCBs to both aquatic and terrestrial organisms. Single-point 24-h Tenax extractions formed the basis for evaluating the bioavailable component of the sediment-associated PCBs with strong correlations to laboratory-based bioaccumulation assays for oligochaetes and chironomid larvae. Stable isotope data suggested that the source of carbon to the food web was relatively constant. Food web samples of emerging insects, fish, and spiders revealed that the PCBs in Campus Lake were bioavailable and the pattern of the PCB signature among food web components followed typical food web processes. The PCB congener pattern was consistent between emergent midges and spiders demonstrating the transfer of PCBs from aquatic to terrestrial species. The PCB concentrations detected in emerging insects from the contaminated area were on average 25 times greater than those detected in emerging insects from reference sites outside the area of greatest sediment contamination. High PCB concentrations found in several species of fish suggested that despite the localized sediment contamination, fish throughout the lake were exposed. These levels also exceeded the fish consumption advisory criteria. The PCB pattern comparisons suggested that the contaminated sediment was the source of exposure throughout the food web. This approach identified the scope of exposure to organisms, demonstrated bioavailability, and provided a basis for future PCB remediation and subsequent monitoring of Campus Lake. In comparison to studies focused solely on limited sampling of fish for consumption advisory purposes, this approach demonstrated the importance of more comprehensive studies to examine the range of ecosystem exposure even from very limited contamination sources.

Download or read book EPA Publications Bibliography written by United States. Environmental Protection Agency and published by . This book was released on 1987 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Indexes written by United States. Environmental Protection Agency and published by . This book was released on 1983 with total page 1760 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Index Medicus written by and published by . This book was released on 2004 with total page 1940 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vols. for 1963- include as pt. 2 of the Jan. issue: Medical subject headings.

Download or read book Modeling Marine Exposure to Polychlorinated Biphenyls from Sunken Ships written by Charles N. Wendt and published by . This book was released on 1996-12-01 with total page 123 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the past, the U.S. Navy has routinely conducted SINKing EXercises (SINKEX) for training, weapon effectiveness tests, and economic disposal of aging assets. Recent concern over polychlorinated biphenyl (PCB) chemicals aboard such target vessels has resulted in a suspension of SINKEX. The U.S. Navy has approximately 200 vessels currently requiring such disposal. Environmental legislation and health concerns preclude selling such vessels to foreign governments or scrapping. This work attempted to model the fate and transport of these PCBs by examining their transport to coastal water and their accumulation in the marine food chain. The model includes biodegradation, upwelling, partitioning of PCBs to sediment, sediment transport, bioaccumulation, biomagnification, and biological migration. Seasonal fluctuations in marine biomass and storm activity and how this affects PCB concentrations is also examined. The model uses a four trophic level approach for the marine food chain. A total of 55 runs, each simulating a 50 year period, were conducted. Model output and subsequent sensitivity analysis of parameters indicate that the potential for adverse impact to the marine ecosystem is minimal.