Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, Institute of Environment and Health, Jianghan University, Wuhan, 430056, China; State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, Institute of Environment and Health, Jianghan University, Wuhan, 430056, China.
Chemosphere. 2021 Jul;275:130011. doi: 10.1016/j.chemosphere.2021.130011. Epub 2021 Feb 21.
Although global mercury (Hg) emission from chlor-alkali industry is decreasing, the legacy Hg may still have potential risks due to its environmental persistence. The objective of this work is to study the biogeochemical cycling and potential risk of Hg in the Ya-Er Lake, which was heavily contaminated by historical chlor-alkali production. Higher concentrations of total Hg (THg) in Ya-Er Lake water (16.8 ± 8.4 ng L) and sediment (547 ± 489 ng g) than other lake systems were observed, reflecting serious Hg pollution in this system. Diffusion rates of Hg at sediment-water interface and budget of Hg showed that release of legacy Hg in sediment (accounting for ∼80%) dominated THg in water, and about 80% methylmercury (MeHg) of total was diffused from sediment. Significant correlations between total organic carbon (TOC) derived from aquaculture and THg diffusion and MeHg concentrations in sediment suggest that TOC plays important roles in controlling legacy Hg release and MeHg production. The actual weekly intakes of Hg via consumption of cultured catfish and wild topmouth culter were higher than the established provisional tolerable weekly intake (PTWI) of MeHg. These results indicated that although the nearby chlor-alkali plant has been shut down for three decades, the release of legacy Hg stored in the sediment still adversely affects this ecosystem. Moreover, aquaculture could enhance MeHg production and control MeHg distribution in the polluted aquatic ecosystem, potentially posing a health risk to surrounding inhabitants through consumption of fish.
尽管全球氯碱行业的汞（Hg）排放量正在减少，但由于其在环境中的持久性，历史遗留的汞仍可能存在潜在风险。本研究旨在研究雅尔湖的汞生物地球化学循环和潜在风险，该湖曾受到历史上氯碱生产的严重污染。与其他湖泊系统相比，雅尔湖水（16.8±8.4ng/L）和沉积物（547±489ng/g）中的总汞（THg）浓度更高，反映出该系统存在严重的汞污染。沉积物-水界面的 Hg 扩散率和 Hg 收支表明，沉积物中历史遗留 Hg 的释放（占∼80%）主导了水中的 THg，约 80%的总甲基汞（MeHg）从沉积物中扩散出来。养殖用水中的总有机碳（TOC）与沉积物中 THg 扩散和 MeHg 浓度之间存在显著相关性，表明 TOC 在控制遗留 Hg 释放和 MeHg 生成方面发挥着重要作用。通过食用养殖的鲶鱼和野生翘嘴红鲌，每周实际摄入的 Hg 量高于已建立的甲基汞暂定每周耐受摄入量（PTWI）。这些结果表明，尽管附近的氯碱厂已经关闭了三十年，但储存在沉积物中的遗留 Hg 的释放仍对该生态系统产生不利影响。此外，水产养殖可以促进 MeHg 的生成，并控制污染水生生态系统中 MeHg 的分布，通过食用鱼类，可能会对周围居民的健康构成威胁。
