University of Chinese Academy of Sciences , Beijing 100049, China.
Observatory Midi-Pyrénées, Geosciences Environment Toulouse Laboratory, Research Institute for the Development (IRD), University of Toulouse and CNRS , 31400 Toulouse, France.
Environ Sci Technol. 2017 Nov 7;51(21):12321-12328. doi: 10.1021/acs.est.7b03510. Epub 2017 Oct 9.
Rice consumption is the primary pathway of methylmercury (MeHg) exposure for residents in mercury-mining areas of Guizhou Province, China. In this study, compound-specific stable isotope analysis (CSIA) of MeHg was performed on rice samples collected in the Wanshan mercury mining area. An enrichment of 2.25‰ in total Hg (THg) δHg was observed between rice and human hair, and THg ΔHg in hair was 0.12‰ higher than the value in rice. Rice and human hair samples in this study show distinct Hg isotope signatures compared to those of fish and human hair of fish consumers collected in China and other areas. Distinct Hg isotope signatures were observed between IHg and MeHg in rice samples (in mean ± standard deviation: δHg at -2.30‰ ± 0.49‰, ΔHg at -0.08‰ ± 0.04‰, n = 7; δHg at -0.80‰ ± 0.25‰, ΔHg at 0.08‰ ± 0.04‰, n = 7). Using a binary mixing model, it is estimated that the atmospheric Hg contributed 31% ± 16% of IHg and 17% ± 11% of THg in the rice samples and the IHg in soil caused by past mining activities contributed to the remaining Hg. This study demonstrated that Hg stable isotopes are good tracers of human MeHg exposure to fish and rice consumption, and the isotope data can be used for identifying the sources of IHg and MeHg in rice.
在中国贵州省汞矿区，居民主要通过食用大米摄入甲基汞（MeHg）。本研究对万山汞矿区采集的大米样品进行了 MeHg 的化合物特异性稳定同位素分析（CSIA）。总汞（THg）δHg 在大米和人发之间观察到 2.25‰的富集，人发中 THg ΔHg 比大米中高 0.12‰。与中国和其他地区的鱼类和鱼类消费者的人发相比，本研究中的大米和人发样品显示出明显不同的汞同位素特征。大米样品中 IHg 和 MeHg 之间观察到明显不同的汞同位素特征（平均值±标准偏差：δHg 为-2.30‰±0.49‰，ΔHg 为-0.08‰±0.04‰，n=7；δHg 为-0.80‰±0.25‰，ΔHg 为 0.08‰±0.04‰，n=7）。使用二元混合模型估计，大气 Hg 贡献了大米样品中 IHg 的 31%±16%和 THg 的 17%±11%，过去采矿活动引起的土壤中 IHg 对剩余 Hg 有贡献。本研究表明，汞稳定同位素是人类通过食用鱼类和大米摄入 MeHg 的良好示踪剂，同位素数据可用于鉴定大米中 IHg 和 MeHg 的来源。
