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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.
This book provides a comprehensive overview of the different dynamic patterns involved in the redistribution of mercury in the global environment, and its impact on human health and ecosystems. Increasing mercury usage and the lack of emission control policy, especially in fast developing countries, represent a complex environmental and political issue that can only benefit from more accurate measurement.
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.
ACKNOWLEDGEMENTS xiv PART I MERCURY AND HUMAN HEALTH B. WHEATLEY and S. PARADIS I Exposure of Canadian Aboriginal Peoples to Methylmercury 3-11 M. GIRARD and C. DUMONT I Exposure of James Bay Cree to Methylmercury during Pregnancy for the Years 1983-91 13-19 M. RICHARDSON, M. MITCHELL, S. COAD and R. RAPHAEL I Exposure to Mercury in Canada: A Multimedia Analysis 21-30 M. RICHARDSON, M. EGYED and D. J. CURRIE I Human Exposure to Mercury may Decrease as Acidic Deposition Increases 31-39 L. E. FLEMING, S. WATKINS, R. KADERMAN, B. LEVIN, D. R. AVYAR, M. BIZZIO, D. STEPHENS and J. A. BEAN I Mercury Exposure in Humans through Food Consumption from the Everglades of Florida 41-48 J. M. GEARHART, H. J. CLEWELL III, K. S. CRUMP, A. M. SHIPP and A. SILVERS I Pharmacokinetic Dose Estimates of Mercury in Children and Dose-Response Curves of Performance Tests in a Large Epidemiological Study 49-58 I. SKARE I Mass Balance and Systemic Uptake of Mercury Released from Dental Amalgam Fillings 59-67 J. DELLINGER, N. KMIECIK, S. GERSTENBERGER and H. NGU I Mercury Contamina tion of Fish in the Ojibwa Diet: I. Walleye Fillets and Skin-On versus Skin-Off Sampling 69-76 J. DELLINGER, L. MALEK and M. BEATTIE I Mercury Contamination of Fish in the Ojibwa Diet: II. Sensory Evoked Responses in Rats Fed Walleye 77-83 H. AKAGI, O. MALM, F. J. P. BRANCHES, Y. KINJO, Y. KASHIMA, J. R. D. GUIMARAES, R. B. OLIVEIRA, K. HARAGUCHI, W. C. PFEIFFER, Y.
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.
"Mercury deposition and contamination is widespread and well documented, and it continues to be a public-health concern for certain sectors of the global human population in both developed and developing countries. This edited volume focuses on integrating the diverse sciences involved in the process of mercury cycling in the environment--from the atmosphere, through terrestrial and aquatic food webs, and human populations--to develop a comprehensive perspective on this important environmental pollutant. Using a systems-level approach, this book provides recommendations on mercury remediation, risk communication, education, and monitoring. In response to a growing need for understanding the cycling of this ubiquitous pollutant, the science of mercury has grown rapidly, expanding into several interdisciplinary fields and encompassing such disparate academic and scientific disciplines as biogeochemistry, economics, sociology, public health, decision sciences, physics, global change, and mathematics. Only recently have scientists really begun to establish more holistic approaches to studying mercury pollution, giving rise to investigations that have furthered the integration of a multi-tiered approach, especially by using chemistry, biology, and human health sciences collectively. The study of mercury pollution has produced a variety of contributions to domestic and international policies related to the management of mercury in the environment"-- Provided by publisher.
An up-to-date overview of the characterization, risk assessment and remediation of mercury-contaminated sites. The book summarizes, for the first time, works from Europe, Russia and the American continent, and review chapters are supplemented by detailed, international case studies.
From Darkness to Light is the true story of how two little-known men, guided by unseen celestial forces, confronted and overcame overwhelming obstacles to create a new understanding of the root causes of world disorder and its bitter fruit of widespread anxiety.