Wang Bo, Yang Shaochen, Li Ping, Qin Chongyang, Wang Chuan, Ali Muhammad Ubaid, Yin Runsheng, Maurice Laurence, Point David, Sonke Jeroen E, Zhang Leiming, Feng Xinbin
State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China; Health Management Center, the Affiliated Hospital of Guizhou Medical University, Guiyang 550009, China.
State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China.
Environ Int. 2023 Apr;174:107891. doi: 10.1016/j.envint.2023.107891. Epub 2023 Mar 20.
Anthropogenic mercury (Hg) emissions have increased significantly since the Industrial Revolution, resulting in severe health impacts to humans. The consumptions of fish and rice were primary human methylmercury (MeHg) exposure pathways in Asia. However, the lifecycle from anthropogenic Hg emissions to human MeHg exposure is not fully understood. In this study, a recently developed approach, termed MeHg Compound-Specific Isotope Analysis (CSIA), was employed to track lifecycle of Hg in four typical Hg-emission areas. Distinct ΔHg of MeHg and inorganic Hg (IHg) were observed among rice, fish and hair. The ΔHg of MeHg averaged at 0.07 ± 0.15 ‰, 0.80 ± 0.55 ‰ and 0.43 ± 0.29 ‰ in rice, fish and hair, respectively, while those of IHg averaged at - 0.08 ± 0.24 ‰, 0.85 ± 0.43 ‰ and - 0.28 ± 0.68 ‰. In paddy ecosystem, ΔHg of MeHg in rice showed slightly positive shifts (∼0.2 ‰) from those of IHg, and comparable ΔHg of IHg between rice grain and raw/processed materials (coal, Hg ore, gold ore and sphalerite) were observed. Simultaneously, it was proved that IHg in fish muscle was partially derived from in vivo demethylation of MeHg. By a binary model, we estimated the relative contributions of rice consumption to human MeHg exposure to be 84 ± 14 %, 58 ± 26 %, 52 ± 20 % and 34 ± 15 % on average in Hg mining area, gold mining area, zinc smelting area and coal-fired power plant area, respectively, and positive shifts of δHg from fish/rice to human hair occurred during human metabolic processes. Therefore, the CSIA approach can be an effective tool for tracking Hg biogeochemical cycle and human exposure, from which new scientific knowledge can be generated to support Hg pollution control policies and to protect human health.
自工业革命以来，人为汞（Hg）排放显著增加，对人类健康造成了严重影响。在亚洲，鱼类和大米的消费是人类甲基汞（MeHg）暴露的主要途径。然而，从人为汞排放到人类甲基汞暴露的生命周期尚未完全明晰。在本研究中，一种最近开发的方法，即甲基汞化合物特异性同位素分析（CSIA），被用于追踪四个典型汞排放区域中汞的生命周期。在大米、鱼类和头发中观察到甲基汞和无机汞（IHg）明显不同的汞同位素分馏值（ΔHg）。甲基汞的ΔHg在大米、鱼类和头发中的平均值分别为0.07±0.15‰、0.80±0.55‰和0.43±0.29‰，而无机汞的ΔHg平均值分别为-0.08±0.24‰、0.85±0.43‰和-0.28±0.68‰。在稻田生态系统中，大米中甲基汞的ΔHg相对于无机汞呈现出轻微的正向偏移（约0.2‰），并且观察到大米籽粒与原材料（煤、汞矿石、金矿石和闪锌矿）之间无机汞的ΔHg相当。同时，研究证明鱼类肌肉中的无机汞部分来源于甲基汞的体内去甲基化。通过二元模型，我们估计在汞矿区、金矿区、锌冶炼区和燃煤电厂区，大米消费对人类甲基汞暴露的平均相对贡献分别为84±14%、58±⒃%、52±20%和34±15%，并且在人类代谢过程中，从鱼类/大米到人类头发的汞同位素比值（δHg）会发生正向偏移。因此，CSIA方法可以成为追踪汞生物地球化学循环和人类暴露的有效工具，从中可以产生新的科学知识，以支持汞污染控制政策并保护人类健康。
