This Special Issue aims to provide new insights into the issue of the mercury contamination of terrestrial and aquatic ecosystems. This ubiquitous contaminant has been used by humans for many years, resulting in global contamination. When this toxic contaminant is converted to methylmercury, it accumulates in trophic chains, which is a major issue for wildlife and human health. The nine articles contained within this Special Issue on ''Mercury and Methylmercury Contamination of Terrestrial and Aquatic Ecosystems'' endeavour to identify the historical evolution of Hg and MeHg levels in aquatic environments, and to evaluate the impact of current and historical human activities, such as mining, climate change, and soil erosion, on receptor ecosystems and food chains.

Experts in the areas of water science and chemistry from the government, industry, and academic arenas discussed ways to maximize opportunities for these disciplines to work together to develop and apply simple technologies while addressing some of the world's key water and health problems. Since global water challenges cross both scientific disciplines, the chemical sciences have the ability to be a key player in improving the lives of billions of people around the world.

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 is widespread in our environment. Methylmercury, one organic form of mercury, can accumulate up the aquatic food chain and lead to high concentrations in predatory fish. When consumed by humans, contaminated fish represent a public health risk. Combustion processes, especially coal-fired power plants, are major sources of mercury contamination in the environment. The U.S. Environmental Protection Agency (EPA) is considering regulating mercury emissions from those plants. Toxicological Effects of Methylmercury reviews the health effects of methylmercury and discusses the estimation of mercury exposure from measured biomarkers, how differences between individuals affect mercury toxicity, and appropriate statistical methods for analysis of the data and thoroughly compares the epidemiological studies available on methylmercury. Included are discussions of current mercury levels on public health and a delineation of the scientific aspects and policy decisions involved in the regulation of mercury. This report is a valuable resource for individuals interested in the public health effects and regulation of mercury. The report also provides an excellent example of the implications of decisions in the risk assessment process for a larger audience.

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.

As rising levels of mercury in the environment pose an increasing threat of toxicity to humans and wildlife, several laws already call for industries to reduce mercury emissions at the source. Ecosystem Responses to Mercury Contamination: Indicators of Change outlines the infrastructure and methods needed to measure, monitor, and regulate the conce