陕西旬阳汞矿区大气降水中汞形态分布特征

Characteristics of mercury species in the atmospheric precipitation from Xunyang mercury mining district in Shaanxi Province

2012年7月—2013年9月对旬阳汞矿区大气降水中总汞、活性汞和溶解气态汞污染特征以及微量元素浓度进行了调查,分析了汞与微量元素浓度之间的相关性。结果表明:旬阳汞矿区大气降水中总汞、活性汞和溶解气态汞浓度的平均值分别为(48±43)、(13±9.0)和(3.8±3.6)ng·L^(-1),浓度变化范围分别为4.4~253、0.39~43和0.41~17 ng·L^(-1);大气降水中活性汞和溶解气态汞分别占总汞浓度的27%和7.9%,其他无机汞形态是其主要存在形态,占总汞浓度的65%;雨水的pH平均值为5.4,变化范围为4.2~6.7;大气降水中Hg和Sb、Se呈显著的正相关,R^2分别为0.67和0.54,说明Hg和Sb、Se具有相同的来源,其中旬阳汞矿的开采和汞锑冶炼等人为释放源为主要贡献源,其次为燃煤源。

Concentrations of total mercury （THg）, reactive mercury （RHg）, and dissolved gaseous mercury （DGM） in precipitation collected from Xunyang Hg mining district in Shaanxi Province from July 2012 to Septernber 2013 were measured. The trace elements in precipitation were analyzed as well. Results showed that average concentrations of THg, RHg, and DGM were （48±43）, （13±9.0）, and （3.8±3.6） ng·L^-1, with ranges of 4.4-253, 0.39-43, and 0.41-17 ng·L^-1, respectively. The fractions of Hg species accounted for 27% in RHg, 7.9% DGM, and 65% in other inorganic forms. The average pH value in rain was 5.4, with a range of 4.2-6.7. Mercury in precipitation exhibited significantly positive correlation with both Sb （R^2=0.54） and Se （R^2=0.67）, indicating a similar source of the three elements due to the Hg mining activities. However, the local coal combustion might be another important source of Hg in wet deposition far from the Hg mining region.