School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, 510275, PR China; State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academic of Sciences, Guiyang, 550081, PR China; College of Resources and Environmental Engineering, Guizhou University, Guiyang, 550025, PR China.
State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academic of Sciences, Guiyang, 550081, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China.
Chemosphere. 2020 Jan;238:124630. doi: 10.1016/j.chemosphere.2019.124630. Epub 2019 Aug 24.
Mercury (Hg) mining activities are an important anthropogenic source of atmospheric Hg. The Xunyang Hg mine located in Shaanxi Province is the largest active Hg producing centre in China. To understand the biogeochemical processes of atmospheric Hg through Hg mining activities, six groups of experimental pots were carefully designed to investigate the effect of Hg mining activities on Hg contamination from atmospheric deposition in the local surface soils. Based on the variations of Hg in the soil from the experimental pots, the deposition flux and loading of Hg in the Xunyang Hg mining district were investigated. The results showed that the average concentration of total gaseous mercury (TGM) as high as 193 ± 122 ng m was observed in the ambient air, which was orders of magnitude higher than that in remote areas. The average deposition flux and annual loading of atmospheric Hg were 72 mg m y and 10 t y, respectively. The dominant atmospheric Hg deposition is within a distance range of 6.0-12 km from the Hg retorting facility, accounting for approximately 85% of the total Hg loading. After 14 months of exposure, total mercury (THg) concentrations in the soil from the experimental pots increased 0.35-9.5 times, and the highest concentrations of methylmercury (MeHg) (3.7 ± 2.9 μg kg) in soil were observed in February. Concentrations as high as 643 μg kg THg and 13 μg kg MeHg in rice were observed in the second experimental year. Elevated concentrations of both THg and MeHg in rice indicated that the newly deposited atmospheric Hg was bioavailable, readily methylated, and taken up by rice, suggesting that the ongoing Hg mining activities cause serious Hg contamination in the soil-rice ecosystem and posed a threat to local residents in the Xunyang Hg mining area.
汞（Hg）矿开采活动是大气 Hg 的重要人为来源。位于陕西省的旬阳汞矿是中国最大的活态汞生产中心。为了了解汞矿开采活动对大气 Hg 生物地球化学过程的影响，设计了六组实验盆，以研究 Hg 矿开采活动对当地表层土壤大气 Hg 污染的影响。根据实验盆中 Hg 的变化，研究了旬阳汞矿区 Hg 的沉降通量和负荷。结果表明，环境空气中总气态汞（TGM）的平均浓度高达 193±122ng·m-3，比偏远地区高出几个数量级。大气 Hg 的平均沉降通量和年负荷分别为 72mg·m-2·y-1和 10t·y-1。大气 Hg 的主要沉降范围在距炼汞设施 6.0-12km 内，约占总 Hg 负荷的 85%。经过 14 个月的暴露，实验盆中土壤的总汞（THg）浓度增加了 0.35-9.5 倍，2 月份土壤中甲基汞（MeHg）的最高浓度（3.7±2.9μg·kg-1）。第二年的实验中，水稻中 THg 和 MeHg 的浓度高达 643μg·kg-1和 13μg·kg-1。水稻中 THg 和 MeHg 的浓度升高表明新沉降的大气 Hg 是生物可利用的，容易甲基化，并被水稻吸收，这表明正在进行的 Hg 矿开采活动导致土壤-水稻生态系统中严重的 Hg 污染，并对旬阳汞矿区的当地居民构成威胁。
