Advances in Mercury Toxicology and Risk Assessment

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PROGRAM SCOPE Mercury (Hg) is a global pollutant, and there is strong evidence that the emission, in particular from coal-burning power plants, will increase by 50% in 2050. Hg is a known neurotoxicant and can have adverse effects on the health of fish, wildlife and human populations in different ecosystems around the world. The long-term goal of my research program is to use innovative approaches to develop state-of-the-art risk assessment tools for the management of environmental pollutants. Our unique research program conducted under the NSERC DG characterizes the effects of Hg toxicity and provides the basic mechanisms that can be extrapolated to predict pollutant effects on ecosystem health. Over the past 6 years of NSERC funding, my team has contributed new insights in the molecular mechanisms of Hg toxicity, its interactions with nutrients such as selenium and long-chain polyunsaturated fatty acids and the development of novel biomarkers for wildlife and human populations. Our research results have been contributed to the wildlife and public health management and policy from the regional to the international levels. The contributions of my NSERC program have trained a significant number of graduate and undergraduate students from all over the world, who have gone on to take positions in university, industry and government. OBJECTIVES OF NSERC PROGRAM I propose to achieve 3 objectives to study the underlying mechanisms of delayed effects of methylmercury (MeHg) prenatal exposure, the modulating effects of gut-microbiota on Hg elimination and the development of biomarkers for Hg exposure in keystone wildlife species with the aim to apply the results of the basic research to risk assessment and risk management purposes. Specific objectives are: 1.To study mechanisms of low dose prenatal MeHg effects on neural precursor development, and the latent effect on adult neurogenesis and memory; 2.To study the effects of diet alteration in gut microbiome on Hg metabolism; and 3.To develop new biomarker tools for assessing Hg effects on wildlife including beluga whales and river otters. A total of 10 BSc, 1 MSc, 6 Ph.D. and 1 PDF will be trained in the proposed program. SIGNIFICANCE AND NOVELTY Our approach of studying the same endpoints in mammalian keystone species (including human) is novel and relevant. The understanding of how fetal exposure to MeHg can cause long-term effects decades later will be groundbreaking. The identification of the relationship between diet, microbiome and MeHg metabolism can potentially increase the capacity of individuals to reduce MeHg body burden/toxicity by manipulating their gut microbiome by modifying their diets. We also have the capacity to use the findings from cutting-edge basic experiments for applied wildlife and epidemiological studies. Our results may be used to establish thresholds for ecosystem health management purposes.