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)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强烈影响的毒素。海洋渔业，特别是沿海生态系统中的海洋渔业，是人类通过食用海鱼和贝类接触甲基汞的主要来源。美国已有48个州发布了反对因甲基汞导致的鱼类消费的建议，包括大西洋海岸和墨西哥湾的沿海建议。暴露风险最大的亚群包括孕妇和儿童以及自给自足的渔民。 到目前为止，关于甲基汞命运的研究还没有调查气候变化变量之间的相互作用，例如温度和营养/碳负荷，尽管它们可能对甲基汞的形成和向人类消费的鱼类和贝类的转移具有协同效应。因此，研究人员建议使用实验室和现场研究，并通过综合建模，详细研究这些因素的单独和综合影响，以检查它们对人类暴露于甲基汞的总体影响。以下三个目标是他们主要假设的基础： 目的1：确定温度、营养物质和碳负荷对沉积物中净甲基汞形成的影响以及沿海生态系统中与之相关的甲基汞向水柱的净输入。 目的2：确定温度和营养供应/生态系统富营养化对初级生产者对甲基汞的生物积累以及河口食物网初级和次级消费者之间转移的交互影响。 目的3：预测气候引起的沿海食物网中甲基汞生物积累的变化将如何增加敏感人群的暴露和风险。 研究人员将应用创新的实验和现场技术来研究这些因素之间的相互作用对河口甲基汞命运的影响。他们将调查南北纬度的地点，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积累的影响。最后，他们将使用实验和现场数据来调整和参数化现有的甲基汞生物地球化学和生物积累模型，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生产的影响，并转移到鱼类，以估计这些变化对人类暴露的净影响。

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.