Download or read book Biogeochemical Cycle of Mercury and Other Trace Metals in Aquatic Systems written by Tianhui Ma and published by . This book was released on 2024 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Trace Metals in Aquatic Systems written by Robert P. Mason and published by John Wiley & Sons. This book was released on 2013-05-13 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a detailed examination of the concentration, form and cycling of trace metals and metalloids through the aquatic biosphere, and has sections dealing with the atmosphere, the ocean, lakes and rivers. It discusses exchanges at the water interface (air/water and sediment/water) and the major drivers of the cycling, concentration and form of trace metals in aquatic systems. The initial chapters focus on the fundamental principles and modelling approaches needed to understand metal concentration, speciation and fate in the aquatic environment, while the later chapters focus on specific environments, with case studies and research highlights. Specific examples deal with metals that are of particular scientific interest, such as mercury, iron, arsenic and zinc, and the book deals with both pollutant and required (nutrient) metals and metalloids. The underlying chemical principles controlling toxicity and bioavailability of these elements to microorganisms and to the aquatic food chain are also discussed. Readership: Graduate students studying environmental chemistry and related topics, as well as scientists and managers interested in the cycling of trace substances in aqueous systems Additional resources for this book can be found at: www.wiley.com/go/mason/tracemetals.
Download or read book Papers Presented at the FAO UNEP WHO IOC IAEA Meeting on the Biogeochemical Cycle of Mercury in the Mediterranean Siena Italy 27 31 August 1984 written by and published by Food & Agriculture Org.. This book was released on 1986 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Biogeochemical Cycle of Mercury in Reservoir Systems in Wujiang River Basin Southwest China written by Xinbin Feng and published by Springer. This book was released on 2017-11-09 with total page 421 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents an intensive study on the biogeochemical cycle of mercury in a river-reservoir system in Wujiang River Basin, the upper branch of the Yangtze River. Six reservoirs located in the mainstream of the Wujiang River and their corresponding inflow/outflow rivers were selected for inclusion in this study, which was conducted by researchers from the Institute of Geochemistry, Chinese Academy of Sciences. The concentration and distribution of Hg in reservoirs (the water column, sediment, sediment pore water), inflow/outflow rivers of reservoirs, and wet deposition in Wujiang River Basin were systematically investigated, and measurements were taken of the water/air exchange flux of gaseous elemental mercury (GEM). On the basis of the data gathered, a detailed mass balance of total mercury (THg) and methylmercury (MeHg) in the six reservoirs was developed. In addition, the book identifies the primary factors controlling Hg methylation in the river-reservoir system in Wujiang River Basin. The accumulation and bio-magnification of Hg species within food chains in reservoirs and human health risk of MeHg exposure through fish consumption are also included in this book.
Download or read book Global Biogeochemical Cycling of Mercury written by Noelle Eckley Selin and published by . This book was released on 2009 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mercury pollution poses global human health and environmental risks. Although mercury is naturally present in the environment, human activities, such as coal burning, have increased the amount of mercury cycling among the land, atmosphere, and ocean by a factor of three to five. Emitted to the atmosphere in its elemental form, mercury travels worldwide before oxidizing to a form that deposits to ecosystems. In aquatic systems, mercury can convert into methylmercury, a potent neurotoxin. People and wildlife are exposed to methylmercury as it bioaccumulates up the food chain. Mercury continues to circulate in the atmosphere, oceans, and terrestrial system for centuries to millennia before it returns to deep-ocean sediments. Areas of uncertainty in the global biogeochemical cycle of mercury include oxidation processes in the atmosphere, land-atmosphere and ocean-atmosphere cycling, and methylation processes in the ocean. National and international policies have addressed direct mercury emissions, but further efforts to reduce risks face numerous political and technical challenges.
Download or read book Mercury in the Biogeochemical Cycle written by Marc Marcotte and published by Springer. This book was released on 2011-10-28 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nowadays, major environmental issues are the object of large public debates de spite the fact that scientific knowledge is often insufficient to draw unequivocal conclusions. Such is the case in the ongoing debate regarding the specific contri butions of anthropogenic greenhouse gas emissions and of natural climate changes to global warming. At least 10 to 20 years of additional observations will be re quired, before we will be able to conclude, with certainty, on this subject. In the mean time, and as directed by their immediate interests, people will continue to promote contradictory opinions. The media are, in part, responsible for perpetuat ing such debates in that they convey indiscriminately the opinion of highly credi ble scientists as that of dogmatic researchers, the latter, unfortunately too often expressing working hypotheses as established facts. Naturally, in a similarly mis informed manner, pressure groups tend to support the researcher whose opinions most closely represent either their particular ideological battles or their economic interests and, hence, in their own way, add further to the confusion and obscurity of the debate. Only a few years ago, mercury (Hg)contamination in hydroelectric reservoirs was the object of such media and social biases. At the time, analytical data used to support the discourse were themselves uncertain and numerous hypotheses, often times fanciful, were proposed and hastily "delivered" to the public.
Download or read book Global and Regional Mercury Cycles Sources Fluxes and Mass Balances written by W. Baeyens and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 572 pages. Available in PDF, EPUB and Kindle. Book excerpt: Essential themes in the biochemical cycling of mercury are the relative importance of anthropogenic versus natural sources, transformation and migration processes at the local, regional and global scale, global emission inventories of different mercury sources (both point and diffuse) of both natural and anthropogenic origin. In this regard, Siberia, with its vast territory and variety of natural zones, is of special interest in the global mercury cycle and in terms of the influence of geographical zones on source and sink terms in regional budgets. Siberia contains large areas of mercuriferous belts; natural deposits that emit mercury into the atmosphere and water. Siberian gold has been mined with the use of mercury since the early 1800s. But there, too, huge forest zones and vast areas of tundra and wetland (bogs) can act as efficient sinks for atmospheric mercury. Audience: Environmental scientists, legislators, politicians and the interested citizen wishing to gain a clear picture of the biogeochemical cycling of mercury.
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.
Download or read book Mercury in the Biogeochemical Environment written by and published by . This book was released on 1973 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Metal Biogeochemistry in Surface water Systems written by John F. Elder and published by . This book was released on 1988 with total page 43 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Biogeochemical Cycling of Mercury in the Atmosphere ocean land System written by Yanxu Zhang and published by . This book was released on 2013 with total page 199 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mercury (Hg) is a ubiquitous trace metal in the environment originating from both natural and anthropogenic sources. It is a pollutant of concern because of the adverse human health effects caused by the consumption of fish and seafood containing methylmercury, which is a neurotoxin. Through development of two transport and chemistry models in the atmosphere and ocean, this dissertation investigates the regional Hg atmospheric transport and wet deposition over North America, and the global ocean Hg cycle as well its perturbation by anthropogenic Hg emissions. Chapter 2 develops a new nested-grid Hg simulation over North America with a 1/2° latitude by 2/3° longitude horizontal resolution employing the GEOS-Chem global chemical transport model. The nested model shows generally improved skill at capturing the high spatial and temporal variability of a variety of observations including wet deposition fluxes, surface concentrations and aircraft measurements of atmospheric Hg. We find that a hypothesized sub-grid rapid in-plume reduction of reactive to elemental Hg improves the model-observation comparison. The nested model suggests that North American anthropogenic emissions account for 10-22% of Hg wet deposition flux over the U.S., depending on whether the in-plume reduction process is included or not. Chapter 3 examines the trends in Hg precipitation concentrations at 47 Mercury Deposition Network (MDN) sites over the United States during 2004 - 2010. We run the model with constant anthropogenic emissions and subtract the model results from the observations in order to remove the influence of meteorological fluctuations. We find significant decreasing trends in the Northeast U.S. ( -4.3±2.2% yr[negative]1) and in the Midwest ( -2.5±1.6% yr[negative]1), but weaker trends over the Southeast ( -0.63±2.5% yr[negative]1) and West (+0.33±7.7% yr[negative]1). Sensitivity simulation with the nested-grid Hg simulation shows that the combination of domestic emission reductions and decreasing background concentrations explains the observed trends over Northeast and Midwest, with domestic emission reductions accounting for 51-33% of the decreasing trends. Chapter 4 implements Hg biogeochemistry in a global 3D offline ocean tracer model, OFFTRAC, and investigate the natural Hg cycle, prior to any anthropogenic input. This model simulates the transformations among different Hg species, and links them to carbon dynamics in the ocean. In the deep ocean, a region which is not expected to be significantly influenced by anthropogenic emissions, the modeled total Hg concentrations (Hg[superscript T], 1.1±0.3 pM) are consistent with observations (1.4±0.9 pM). High concentrations in the mixed layer are modeled at Southern Ocean, coastal regions, closed and shallow water body, western Equatorial Pacific Ocean. The modeled Hg[superscript T] concentrations in the deep old North Pacific waters are a factor of two higher than in the younger the deep North Atlantic because of the longer time to accumulate Hg sinking from the surface. The modeled fraction of elemental Hg (Hg0[subscript aq) is also higher in aged deep waters because of the slow accumulation of Hg0[subscript aq] generated by reduction of oxidized Hg in subsurface waters. Chapter 5 focuses on the perturbation of legacy anthropogenic Hg emissions (1450 - 2008) on oceanic Hg cycle. We couple the OFFTRAC-Hg simulation developed in Chapter 4 with the GEOS-Chem atmospheric Hg simulation. According to the model, the total Hg mass in the global ocean has increased from 1150 Mmol in 1450 to a present-day value of 1640 Mmol. The modeled anthropogenic Hg concentrations peak at a depth of 400-500 m. The model result shows that approximately 43% (210 Mmol) of the anthropogenic Hg resides at depths below the mixed layer and shallower than 1000 m, 55% (270 Mmol) at depths deeper than 1000 m, while only approximately 2% (10 Mmol) in the mixed layer. The model also suggests that sinking with particulate organic carbon is the major pathway for the anthropogenic Hg to penetrate into the deep ocean. The modeled anthropogenic Hg concentrations are higher over the east tropical Pacific Ocean, the east tropical Atlantic Ocean, tropical Indian, west coast of continents, and high-latitude North Pacific and Atlantic Oceans, while being lower over centers of mid-latitude gyres and the Arctic Ocean.
Download or read book Global Biogeochemical Cycling of Mercury written by Noelle E. Selin and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Mercury pollution poses global human health and environmental risks. Although mercury is naturally present in the environment, human activities, such as coal burning, have increased the amount of mercury cycling among the land, atmosphere, and ocean by a factor of three to five. Emitted to the atmosphere in its elemental form, mercury travels worldwide before oxidizing to a form that deposits to ecosystems. In aquatic systems, mercury can convert into methylmercury, a potent neurotoxin. People and wildlife are exposed to methylmercury as it bioaccumulates up the food chain. Mercury continues to circulate in the atmosphere, oceans, and terrestrial system for centuries to millennia before it returns to deep-ocean sediments. Areas of uncertainty in the global biogeochemical cycle of mercury include oxidation processes in the atmosphere, land-atmosphere and ocean-atmosphere cycling, and methylation processes in the ocean. National and international policies have addressed direct mercury emissions, but further efforts to reduce risks face numerous political and technical challenges.
Download or read book Mercury in the Biogeochemical Cycle written by Marc Lucotte and published by . This book was released on 1999-05-04 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Changing Metal Cycles and Human Health written by J.O. Nriagu and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt: of metal interactions with subcellular biochemical systems usually either are metabolites of the system affected (porphyrinurias) or represent some specific function of a cellular system being impaired (proteinurias). One typically finds a continuum of symptoms, from the subtle or so-called "no effect" bio chemical and physiological indicators of exposure to severe clinical disease and death. This continuum is the basis of much of the controversy since many health officials follow the traditional practice of applying the "threshold health-effect" concept in evaluating the problems of environmental exposure to metals. The past decade or so, however, has seen a vast increase in our understanding of the effects of elevated concentrations of toxic metals in local populations and ecosystems. At the same time, there is a growing awareness that the effects of the metals which occur naturally in the environment must be distinguished from those imposed by the pollutant fraction. This point was amply document ed in a recent study of cadmium intake and cadmium in a number of human tissues in Sweden, Japan, and the United States, which showed fairly conclu sively that the background exposure in Japan was about threefold higher than in the other two countries (2). One immediate implication is that any health ef fect studies of cadmium in Japan using control groups within that country are liable to underestimate the difference between the exposed and the control groups simply because of the the high "background" intake.
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 Metal Ions in Biological Systems written by Astrid Sigel and published by CRC Press. This book was released on 1997-02-14 with total page 656 pages. Available in PDF, EPUB and Kindle. Book excerpt: Details analytical methods for the determination of mercury and covers the biogeochemical cycling of mercury in lakes, rivers, oceans, the soil and the atmosphere. This volume also examines the microbial transformation of mercury species, their accumulation in the food chain, the physiology and toxicology, and more.
Download or read book Metal Ions In Biological Systems Volume 44 written by Helmut Sigel and published by CRC Press. This book was released on 2005-03-01 with total page 347 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volume 44, devoted solely to the vital research areas concerning the biogeochemistry of metals and their transport in the environment and availability to living systems, offers 9 timely and authoritative chapters on these fascinating topics by 19 internationally recognized experts.
