Download or read book Mercury Bioaccumulation and Biomagnification in the Warmwater Fish Communities of Two Connecticut Lakes with an Examination of Seasonal Variations in Mercury Concentrations written by Scott M. Ward and published by . This book was released on 1997 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mercury in Fish written by Collin Aaron Eagles-Smith and published by . This book was released on 2006 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mercury in Fish Bed Sediment and Water from Streams Across the United States 1998 2005 written by Barbara C. Scudder and published by DIANE Publishing. This book was released on 2010-08 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: Report on how mercury (Hg) was examined in top-predator fish, bed sediment, and water from streams that spanned regional and national gradients of Hg source strength and other factors thought to influence methylmercury bioaccum. Sampled settings include stream basins that were agr¿l, urbanized, undeveloped, and mined. Predator fish were targeted for collection, and composited samples of fish were analyzed for total Hg (THg), as most of the Hg found in fish tissue is MeHg. Samples of bed sediment and stream water were analyzed for THg, MeHg, and characteristics thought to affect Hg methylation, such as loss-on-ignition and acid-volatile sulfide in bed sediment, and pH, dissolved organic carbon, and dissolved sulfate in water. Illus.
Download or read book Mercury Cycling in a Remote Boreal Drainage Basin written by Gretchen Lynne Lescord and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The consumption of freshwater fish and seafood is the main source of mercury (Hg), a widespread neurotoxic pollutant, in humans, a fact which has sparked decades of research on Hg cycling in aquatic systems. More specifically, the formation and bioaccumulation of methylmercury (MeHg) is of particular importance because it biomagnifies through aquatic food webs, resulting in relatively high levels in predatory fish despite typically low concentrations in the surrounding water. The main goal of this thesis was to assess how various watershed-level processes affect Hg bioaccumulation and biomagnification through freshwater food webs across the relatively pristine Attawapiskat Drainage Basin (ADB) in the remote Far North of Ontario. This watershed overlaps with the mineral-rich region known as the "Ring of Fire" which is expected to be heavily developed in the coming decades, likely altering the physico-chemical environments of surrounding lakes and rivers. In total, 58 lakes and river sites across the ADB were sampled for surface water quality, aquatic macroinvertebrates, and fish from 2014 to 2016. Water samples were analyzed for 39 chemical parameters including total Hg (THg; the sum of all Hg species) and MeHg concentrations ([MeHg]). Biotic samples were analyzed for [THg] and/or [MeHg], as well as carbon and nitrogen stable isotope ratios, which are indicative of an animal's food web position. In Chapter 1 of this thesis, I provide an overview of our current knowledge on Hg cycling in aquatic systems of the boreal region. In Chapter 2, I present an extensive assessment of the chemical, physical, and ecological gradients across the ADB, and an analysis of the relationships between Hg and these environmental gradients. I determined that less productive systems with higher concentrations of dissolved organic matter (DOM) had higher aqueous and biotic [Hg]. In Chapter 3, I examined how changes in the quality of DOM across the ADB relate to [Hg] in water and biota. Findings from this study suggest that more labile DOM complexes enhance MeHg bioaccumulation into food webs, while systems with more humic and aromatic DOM had higher aqueous total [Hg]. The fourth chapter critically examined the speciation of Hg in fish from across the ADB and showed substantially lower percentages of MeHg (relative to total Hg) in muscle of smaller-sized fish, particularly those which feed on littoral-based food webs and had higher lipid content in their tissue. These novel findings challenge the general assumption, used in many biomagnification studies and consumption guidelines, that all fish muscle tissue has > 95% MeHg. Finally, in Chapter 5, I discuss the implications of my research for subsistence fishers, specifically those from remote communities, where freshwater fish are important for both culture and sustenance. Here I developed some preliminary approaches to better communicating the risks and benefits of consuming fish when presenting fish tissue contaminant results in remote northern communities, including those in and around the ADB. Understanding the major influences on MeHg cycling is vital to properly monitoring the effects of industrial development (e.g., the Ring of Fire development) and climate change, which can greatly alter the physico-chemical environment of surrounding lakes and rivers. The results from my thesis indicate significant physical and chemical differences between waters in the two ecozones (i.e., the Boreal Shield and Hudson Bay Lowlands) across the ADB, presumably due to changes in bedrock geology and riparian characteristics. No other study, to my knowledge, has explored the effects of landscape position and the associated changes in physico-chemical characteristics on Hg bioaccumulation, speciation, and biomagnification on such a large scale. My findings demonstrate that monitoring programs will need to effectively track changing nutrient concentrations, DOM characteristics, and Hg bioaccumulation patterns that vary across large spatial gradients.
Download or read book Environmental Contaminants in Biota written by W. Nelson Beyer and published by CRC Press. This book was released on 2011-02-23 with total page 750 pages. Available in PDF, EPUB and Kindle. Book excerpt: Examining tissue residues of contaminants in biota reveals the movement of contaminants within organisms and through food chains as well as the context for understanding and quantifying injuries to organisms and their communities. Yet tissue concentrations of some contaminants are especially challenging to interpret and the ability of today’s analytical chemists to provide reliable analytical data of most important environmental contaminants often surpasses the ability of ecotoxicologists to interpret those data. Offering guidance on the ecotoxicologically meaningful interpretation of tissue concentrations, Environmental Contaminants in Biota, Interpreting Tissue Concentrations, Second Edition is updated with current data and new ways of analyzing those data as well as additional contaminants not previously considered. Beginning with a history of wildlife toxicology and data interpretation, chapters cover a wide range of contaminants and their hazardous and lethal concentrations in various animals including DDT, Dioxins, PCBs, and PBDEs in aquatic organisms; methylmurcury, selenium, and trace metals in fishes and aquatic invertebrates; and pharmaceuticals and organic contaminants in marine mammals. The book considers the impact of Polychlorinated Biphenyls, Dibenzo-p-Dioxins and Dibenzofurans, and Polybrominated Diphenyl Ethers; cyclodiene; and other organochlorine pesticides in birds and mammals. Later chapters examine the effects and analysis of lead, cadmium, and radionuclides in biota. With thousands of published research papers reporting tissue concentrations each year, Environmental Contaminants in Biota, Interpreting Tissue Concentrations, Second Edition gives ecotoxicologists the ability to draw actionable value regarding the toxicological consequences of those concentrations and relate tissue concentrations quantitatively to injury: the core of ecotoxicology.
Download or read book The Seasonal and Spatial Variations of Mercury Methylation and Methylmercury Decomposition in an Oligotrophic Northern Wisconsin Lake written by Eric T. Korthals and published by . This book was released on 1986 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt: The formation of methylmercury represents a potentially serious problem in aquatic ecosystems because of its toxicity and accumulation in aquatic biota. Elevated levels of mercury in edible fish have recently been reported for several lakes in Northern Wisconsin. The majority of mercury in fish tissue is in the methylated form, suggesting that biological mercury methylation is a key process regulating mercury levels in fish. Numerous studies have examined mercury methylation in aquatic ecosystems but most have addressed only net rates of methylmercury production. The net amount of methylmercury produced in the aquatic environment is dependent on both methylation and demethylation. Recent studies have examined the effects of pH on mercury methylation and demethylation in several lakes in Canada and Northern Wisconsin. However, little else is known about the relative rates of these simultaneous processes in aquatic ecosystems. The purpose of this study was to examine where and when the potential for methylation was the greatest in Lake Clara; to examine the products of microbial demethylation; and to examine the effects of acidification on methylation and demethylation. Microbial mercury methylation and methylmercury decomposition were examined in Lake Clara, an oligotrophic Northern Wisconsin seepage lake, using 203Hg(N03)2 and 14cH3Hgi, respectively. The primary sites for mercury methylation in Lake Clara were in the surficial sediments of the backwater area and the littoral-profundal transitionary zone. Mercury methylation in surficial sediments was greatest from mid-July through September. The potential for methylation in the water column and attached microbial communities was low; whereas, demethylation activity was substantially greater. Thus, the net rate of methylmercury production may be significantly affected by demethylation activity.
Download or read book Preliminary Assessment of Total Mercury Concentrations in Fishes from Rivers Lakes and Reservoirs in New Jersey written by and published by . This book was released on 1994 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Preliminary Assessment of Total Mercury Concentrations in Fishes from Connecticut Water Bodies written by Robert M. Neumann and published by . This book was released on 1996 with total page 117 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Patterns of Mercury in Aquatic Biota in Twin Lakes Washington written by Piper Elizabeth Marshall and published by . This book was released on 2011 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mercury Concentrations in Yellow Perch Perca Flavescens from 24 Lakes at Kejimkujik National Park Nova Scotia written by Jennifer A. Carter and published by [Halifax, N.S.] : Parks Canada. This book was released on 2001 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: As part of a wider study on the bioaccumulation & ecological effects of mercury in freshwater fish & wildlife in Canada, this study measured total mercury in yellow perch from 24 lakes in Nova Scotia. The objectives of the study were to assess mercury concentrations in prey of common loons, which themselves have high mercury levels, and to determine which environmental factors were associated with differences in fish mercury concentrations from lake to lake. Results presented include mean perch mercury concentration & concentration range, correlations of fish characteristics with whole-fish mercury concentrations, and correlations of water chemistry parameters with fish mercury concentrations.
Download or read book Mercury in the Environment written by Michael S. Bank and published by Univ of California Press. This book was released on 2012-05-31 with total page 361 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mercury pollution and contamination are widespread, well documented, and continue to pose a public health concern in both developed and developing countries. In response to a growing need for understanding the cycling of this ubiquitous pollutant, the science of mercury has grown rapidly to include the fields of biogeochemistry, economics, sociology, public health, decision sciences, physics, global change, and mathematics. Only recently have scientists begun to establish a holistic approach to studying mercury pollution that integrates chemistry, biology, and human health sciences. Mercury in the Environment follows the process of mercury cycling through the atmosphere, through terrestrial and aquatic food webs, and through human populations to develop a comprehensive perspective on this important environmental problem. This timely reference also provides recommendations on mercury remediation, risk communication, education, and monitoring.
Download or read book Relationships Between Largemouth Bass Mercury Concentrations and Environmental Characteristics of Connecticut Lakes written by Robert Peter Hanten and published by . This book was released on 1997 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mercury Pollution Integration and Synthesis written by Carl J. Watras and published by CRC Press. This book was released on 1994-11-11 with total page 760 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains 57 chapters describing the results of original research and reviewing the state-of-the-science with respect to environmental mercury. Topics include analytical methodology, atmospheric cycling, freshwater and marine ecosystems, terrestrial processes, bioaccumulation, modeling, pollution and remediation, and human health and public policy.
Download or read book Advances in Mercury Toxicology written by Tsuguyoshi Suzuki and published by Springer Science & Business Media. This book was released on 1991 with total page 516 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Understanding Mercury Transformations in the Lower Freshwater Food Web Through the Lens of Mercury Stable Isotopes written by Grace Jane Armstrong and published by . This book was released on 2024 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mercury stable isotope ratios can be used to trace Hg sources and transformation processes across diverse ecosystems. While their application has been useful for sediments and fish, they have been difficult to apply in lower trophic biota due to low tissue concentrations, analytical difficulties, and lack of knowledge regarding fractionation prior to bioaccumulation. This dissertation leverages laboratory-based uptake and photochemistry experiments to understand Hg cycling in seasonal eutrophic lakes and in Lake Huron. Benchtop uptake and photochemistry experiments (Chapter 2) spanned diverse dissolved organic matter (DOM) conditions in the presence of freshwater plankton, Raphidocelis subcapitata. DOM highly influenced uptake concentrations and photodegradation-induced fractionation and the presence of phytoplankton reduced photodemethylation. Minimal fractionation was observed during uptake. This study calls for caution when applying simple photochemical corrections across diverse ecosystems. Eutrophic lakes were sampled monthly to determine how Hg cycling, bioaccumulation, and source reactivity are influenced by seasonal fluctuations in plankton communities and water column structure (Chapter 3). Hg species concentrations varied seasonally in water and seston. Water column production of MeHg was observed to be an important source of MeHg during stratification and spring and fall turnover were demonstrated as key times of bioaccumulation. MeHg stable isotopes further elucidated that seston and fish predominantly bioaccumulated MeHg from pelagic Hg sources, likely tied to metalimnetic MeHg production. Lastly, binational fieldwork (Chapter 4) was conducted in Lake Huron to assess (1) Hg dynamics in nearshore and offshore zones, (2) sediment Hg source distribution, (3) Hg concentrations in benthic and pelagic biomonitors, and (4) the influence of legacy contamination in Saginaw Bay on biota MeHg burdens. Nearshore seston MeHg were consistently higher than offshore collections, owing to riverine MeHg inputs. The source of Hg varied across sediments, with offshore zones receiving mostly atmospheric inputs and nearshore regions were influenced by industrial and watershed-derived sources. Saginaw Bay sediment legacy contamination was not reflected in biota. We recommend continued monitoring of biomonitors to assess the response of Hg bioaccumulation to land use changes, remediation efforts, and reductions in Hg emissions, key for determining effective Hg management strategies for the Great Lakes.
Download or read book Environmental Chemistry of Lakes and Reservoirs written by Lawrence A. Baker and published by . This book was released on 1994 with total page 648 pages. Available in PDF, EPUB and Kindle. Book excerpt: Developed from a symposium at the 201st National Meeting of the ACS in Atlanta, April 1991, this broad-ranging investigation, practical in orientation, is designed to meet the needs not only of chemists, but also environmental engineers and biologists, and scientists involved in practical aspects of water pollution, as well as those with a theoretical bent. It describes lake geochemistry, the cycling and distribution of major elements in aquatic systems, the behavior of trace metals in lakes, and organic contaminants. Theory, practical techniques, potential research, and policy implications are discussed. Annotation copyright by Book News, Inc., Portland, OR
Download or read book Environmental Chemistry and Toxicology of Mercury written by Guangliang Liu and published by John Wiley & Sons. This book was released on 2011-11-07 with total page 435 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides the fundamentals, recent developments, and future research needs for critical mercury transformation and transport processes, as well as the experimental methods that have been employed in recent studies. The coverage discusses the environmental behavior and toxicological effects of mercury on organisms, including humans, and provides case studies at the end of each chapter. Bringing together information normally spread across several books, this text is unique in covering the entire mercury cycle and providing a baseline for what is known and what uncertainties remain in respect to mercury cycling.
