Climate impact on coastal ecosystem methylmercury: human exposure implications

描述（由申请人提供） 汞（Hg）是CERCLA危险物质优先清单（2011年）上的第三大污染物，其有机和有毒形式甲基汞（MeHg）是一种对人类健康有影响的强效毒素。 海洋渔业，特别是沿海生态系统中的海洋渔业，是人类通过食用海洋鱼类和贝类接触甲基汞的主要来源。 美国有48个州发布了禁止食用含有甲基汞的鱼类的禁令，包括大西洋沿岸和墨西哥湾的沿海禁令。 最有可能接触的亚群体包括孕妇、儿童和自给渔民。 迄今为止，关于甲基汞归宿的研究尚未调查温度和营养/碳负荷等气候变化变量之间的相互作用，尽管它们可能对甲基汞的形成和转移到人类食用的鱼类和贝类产生协同效应。因此，研究人员建议通过实验室和实地研究，详细审查这些因素的单独和综合影响，并通过综合建模来审查它们对人类接触甲基汞的总体影响。以下三个目标是他们主要假设的基础： 目标1：确定温度、营养物和碳负荷对沉积物中甲基汞净形成的影响，以及沿海生态系统中甲基汞向水体的相关净输入。 目标二：确定温度和营养供应/生态系统富营养化对初级生产者甲基汞生物累积的相互影响，以及河口食物网初级消费者和次级消费者之间的转移。 目标3：预测气候引起的沿海食物网中甲基汞生物累积的变化将如何增加敏感人群的接触和风险。 研究人员将采用创新的实验和现场技术，调查这些因素对河口甲基汞命运之间的相互作用。 他们将调查北方和南方纬度的地点，以确定自然温度范围对河口生态系统中甲基汞生产和生物累积的影响。 最后，他们将利用实验和实地数据，调整和参数化现有的甲基汞地球化学和生物累积模型，以包括温度和营养/碳负荷的变化。这些工具将使他们能够预测气候变化变量对甲基汞产生和向鱼类转移的影响，以估计这些变化对人类接触的净影响。 公共卫生相关性：甲基汞是一种影响人类健康的全球性毒素，海洋生态系统是人类通过食用海洋鱼类和贝类接触甲基汞的主要来源。河口生态系统既是海洋食物网中甲基汞的主要来源，也是气候引起的变化以及营养和碳负荷对甲基汞的产生、转移和生物积累产生复杂影响的地方。 研究人员将研究这些对了解未来至关重要的互动效应 甲基汞对人体接触和健康的影响。

DESCRIPTION (provided by applicant) Mercury (Hg) is the third most important contaminant on the CERCLA Priority List of Hazardous Substances (2011) and its organic and toxic form, methyl mercury (MeHg), is a potent toxin with human health effects. Marine fisheries particularly in coastal ecosystems are dominant sources of human exposure to MeHg through consumption of marine fish and shellfish. 48 states in the U.S. have issued advisories against consumption of fish due to MeHg, including coastal advisories for the Atlantic Coast and the Gulf of Mexico. Sub-populations most at risk for exposure include pregnant women and children and subsistence fishers. To date, research on MeHg fate has not investigated the interaction of climate change variables such as temperature and nutrient/carbon loading even though they are likely to have synergistic effects on the formation and transfer of MeHg to the fish and shellfish that humans consume. The investigators therefore propose to examine in detail individual and combined effects of these factors using laboratory and field studies, and through integrative modeling to examine their overall impact on human exposure to MeHg. The following three aims are the basis for their primary hypotheses: Aim 1: Determine the effects of temperature, nutrient and carbon loading on the net MeHg formation in sediments and the associated net inputs of MeHg to the water column in coastal ecosystems. Aim 2: Determine the interactive effects of temperature and nutrient supply/ecosystem eutrophication on bioaccumulation of MeHg by primary producers, and transfer between primary and secondary consumers in estuarine food webs. Aim 3: Predict how climate-induced changes in MeHg bioaccumulation in coastal food webs will increase exposure and risk to sensitive populations. The investigators will apply innovative experimental and field techniques to investigate the interactions between these factors on MeHg fate in estuaries. They will investigate sites in northern and southern latitudes to determine the influence of a natural range of temperatures on MeHg production and bioaccumulation in estuarine ecosystems. Finally, they will use experimental and field data to adapt and parameterize an existing MeHg biogeochemistry and bioaccumulation model to include variation in temperature and nutrient/carbon loading. These tools will allow them to predict the effects of climate change variables on MeHg production and transfer to fish to estimate the net effect of these changes on human exposure. Public Health Relevance: Methyl mercury (MeHg) is a global toxin impacting human health, and marine ecosystems are dominant sources of human exposure through consumption of marine fish and shellfish. Estuarine ecosystems are both a major source of MeHg to marine food webs and locations where climate induced changes and nutrient and carbon loading will have complex effects on the production, transfer, and bioaccumulation of MeHg. The investigators will examine these interactive effects which are critical to understanding the future impact of MeHg on human exposure and health.