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Abstract：
Rice plants accumulate Hg from the soil and ambient air, however, evaluating the contribution of Hg from these two sources remains challenging. Here, we proposed a practical method to predict the contribution of total gaseous mercury (TGM) to Hg in white rice in Wanshan Hg mine area (WMM). In this study, rice was planted in the same low-Hg soil at different sites of WMM with varying TGM levels. Comparing to the control sites at IG (Institute of Geochemistry, Guiyang), TGM is the dominant source of Hg in rice leaves and white rice at TB (Tianba) and ZJW (Zhangjiawan) sites of WMM. Subsequently, a good correlation between the Hg concentrations in rice leaves and the concentration contributions of TGM to Hg in white rice was obtained. Such a correlation enabled feasible quantification of the contribution of TGM to Hg in white rice collected from the Wanshan Hg mine. The contribution of TGM to Hg in white rice across the WMM area was also estimated, demonstrating that white rice receives 14-83% of Hg from the air. Considering the high contribution of TGM to Hg in white rice, we compared the relative health risks of Hg via inhalation and rice consumption and found that inhalation, rather than rice consumption, was the major pathway for bioaccessible Hg exposure in adults at high-TGM sites. This study provides new knowledge of Hg biogeochemistry in Hg-mining areas.
摘要：
水稻植物从土壤和环境空气中积累汞，然而,评估这两种来源的汞的贡献仍然具有挑战性。这里,提出了一种实用的方法来预测万山汞矿区（WMM）白米中气态总汞（TGM）对汞的贡献。在这项研究中,水稻种植在不同TGM水平的WMM不同地点的相同低汞土壤中。与IG(地球化学研究所的对照地点相比，贵阳），TGM是WMM的TB（田坝）和ZJW（张家湾）站点水稻叶片和白米中汞的主要来源。随后，水稻叶片中的Hg浓度与TGM对白米中Hg的浓度贡献之间具有良好的相关性。这种相关性使从万山汞矿收集的白米中TGM对汞的贡献成为可能。还估计了整个WMM地区TGM对白米中Hg的贡献，证明白米从空气中吸收14-83%的汞。考虑到TGM对白米中汞的高贡献，我们比较了汞通过吸入和大米消费的相对健康风险，而不是大米消费，是高TGM点成人生物可接触汞的主要途径。本研究提供了汞矿区汞生物地球化学的新知识。
