Methylmercury Production and Fate in Response to Multiple Environmental Factors

项目2：摘要 在美国和全球，食用受汞污染的鱼是一个严重的公共卫生问题。 海鱼是人类接触甲基汞(MeHg)的最重要因素，甲基汞是毒性最大的 汞的一种形式。甲基汞暴露对孕妇和儿童特别令人担忧，并已知道 神经、发育、心血管和免疫方面的影响。项目2的总体目标是 确定多种环境因素的变化将如何改变甲基汞的生产和命运 河口食物网，这是接触人类的重要途径。我们将调查互动的 温度、盐度和碳含量变化对产量的影响(添加剂和非添加剂) 和沿海海洋系统中甲基汞的去向，以便也预测区域变化的净影响 气候变化对人类接触甲基汞的影响。该项目将利用实地研究和实验室 测量一系列与环境有关的温度、盐度和碳影响的实验 微生物活性、汞甲基化和甲基汞去甲基化速率、沉积物中甲基汞含量和汞和汞的负荷 从沉积物到上覆水的甲基汞通量。将进行实验室和中观实验，以 考察温度、盐度和有机碳对生物多样性的单独和综合影响 甲基汞在浮游植物中的生物浓缩，以及对浮游动物和鱼类的营养转移 人类食用的营养级别较高的鱼。野外工作和中温带实验将在#年进行。 位于不同纬度、沉积物中碳含量高和低的河口，以便 比较不同生物地球化学和温度条件下的甲基汞过程。数据获取自 实验室和现场实验将用于将当前的命运、运输和 生物蓄积模型与人体暴露模型。这些结合起来的方法将改善我们的 认识复杂环境变化对海洋中甲基汞去向和生物积累的影响 生态系统，以及这些因素对人类接触甲基汞的影响。

Project 2: Abstract Consumption of fish contaminated with mercury is a serious public health concern in the US and globally. Marine fish are the most important agents of exposure for humans to methylmercury (MeHg), the most toxic form of mercury. MeHg exposure is of particular concern for pregnant women and children and has known neurological, developmental, cardiovascular, and immunological effects. The overall goal of Project 2 is to determine how changes in multiple environmental factors will alter the production and fate of MeHg in estuarine food webs, which are important pathways of exposure to humans. We will investigate the interactive effects (additive and non-additive) of changes in temperature, salinity, and carbon content on the production and fate of MeHg in coastal marine systems in order to predict the net influence of regional variability as well as climate change on human exposure to MeHg. The project will utilize field studies and laboratory experiments to measure the effect of a range of environmentally relevant temperatures, salinities, and carbon loads on microbial activity, Hg methylation and MeHg demethylation rates, sediment MeHg content and Hg and MeHg flux from sediments to overlying water. Laboratory and mesocosm experiments will be conducted to examine the individual and combined effects of temperature, salinity and organic carbon on the bioconcentration of MeHg into phytoplankton, and trophic transfer to zooplankton and fish that are prey for higher trophic level fish consumed by humans. Field work and mesocosms experiments will be undertaken in estuaries located at different latitudes with high and low carbon concentrations in sediments in order to compare MeHg processes under different biogeochemical and temperature regimes. Data obtained from laboratory and field experiments will be used to parameterize and link current fate, transport, and bioaccumulation models with human exposure models. These combined approaches will improve our understanding of the impact of complex environmental alterations on MeHg fate and bioaccumulation in marine ecosystems, and the impact of these factors on MeHg exposure to humans.