Environmental Origins of Methylmercury Accumulated in Subarctic Estuarine Fish Indicated by Mercury Stable Isotopes.
Environmental Origins of Methylmercury Accumulated in Subarctic Estuarine Fish Indicated by Mercury Stable Isotopes.
复制标题
DOI：
10.1021/acs.est.6b03206
复制
发表时间：
2016-10
影响因子：
11.4
通讯作者：
Miling Li;A. Schartup;A. Valberg;Jessica D. Ewald;D. Krabbenhoft;R. Yin;P. Balcom;E. Sunderland
中科院分区：
文献类型：
--
作者：
Miling Li;A. Schartup;A. Valberg;Jessica D. Ewald;D. Krabbenhoft;R. Yin;P. Balcom;E. Sunderland
甲基汞（MeHg）暴露会对生殖和神经发育健康造成不良影响。河口鱼类可能会接触到河流及其流域、海底沉积物和海洋水体中产生的甲基汞，但人们对每种来源的相对重要性知之甚少。为了更好地了解甲基汞暴露源，我们测量了亚北极大型沿海生态系统鱼类中汞（δ 202 Hg，Δ 199 Hg和Δ 201 Hg），碳（δ 13 C）和氮（δ 15 N）的稳定同位素。我们确定了两个不同的食物链暴露于主要是淡水和海洋甲基汞来源，但没有发现证据的底栖海洋甲基汞签名。这与我们以前的研究一致，表明底栖沉积物是河口甲基汞的净汇。海水鱼的Δ 199 Hg值（0.78‰ ~ 1.77‰）低于淡水鱼（0.72‰ ~ 3.14‰），且变化较小; δ 202 Hg值高于淡水鱼（0.1‰ ~ 0.57‰;-0.76‰ ~ 0.15‰）。我们观察到的汞同位素组成的少年和成年彩虹胡瓜鱼（Osmerus mordax）的转变时，他们的淡水和海洋环境之间的过渡，他们的主要觅食领土。大西洋鲑鱼（萨尔莫salar）的汞同位素组成表明，尽管它们在淡水地区度过的时间相似或更长，但它们从海洋环境中接收了大部分甲基汞。我们的结论是，稳定的汞同位素有效地跟踪鱼类甲基汞暴露源在不同的个体发育阶段。
Methylmercury (MeHg) exposure can cause adverse reproductive and neurodevelopmental health effects. Estuarine fish may be exposed to MeHg produced in rivers and their watersheds, benthic sediment, and the marine water column, but the relative importance of each source is poorly understood. We measured stable isotopes of mercury (δ202Hg, Δ199Hg, and Δ201Hg), carbon (δ13C), and nitrogen (δ15N) in fish with contrasting habitats from a large subarctic coastal ecosystem to better understand MeHg exposure sources. We identify two distinct food chains exposed to predominantly freshwater and marine MeHg sources but do not find evidence for a benthic marine MeHg signature. This is consistent with our previous research showing benthic sediment is a net sink for MeHg in the estuary. Marine fish display lower and less variable Δ199Hg values (0.78‰ to 1.77‰) than freshwater fish (0.72‰ to 3.14‰) and higher δ202Hg values (marine: 0.1‰ to 0.57‰; freshwater: -0.76‰ to 0.15‰). We observe a shift in the Hg isotopic composition of juvenile and adult rainbow smelt (Osmerus mordax) when they transition between the freshwater and marine environment as their dominant foraging territory. The Hg isotopic composition of Atlantic salmon (Salmo salar) indicates they receive most of their MeHg from the marine environment despite a similar or longer duration spent in freshwater regions. We conclude that stable Hg isotopes effectively track fish MeHg exposure sources across different ontogenic stages.