贵阳市大气降水中汞的分布特征

Distribution characteristics of mercury in precipitation of Guiyang,China

于2008年7—9月对贵阳市中心城区采集的21个大气降水进行了总汞、甲基汞及阴、阳离子浓度的测定,分析了大气降水中总汞与阴阳离子间的相互关系。结果表明：大气降水中总汞的平均含量为18 ng.L-1,变化范围为0.4~57.4 ng.L-1;甲基汞的平均含量为0.07 ng.L-1,变化范围为0.02~0.2 ng.L-1。大气降水中的阴离子以SO24-和NO-3为主,其浓度平均值分别为151和145 mo.lL-1;阳离子主要以Ca2＋为主,平均浓度达到了123 mo.lL-1,变化范围为3.7~560 mo.lL-1,其次是NH4＋和Mg2＋,其浓度平均值分别为52.2和20.4 mo.lL-1。通过分析降水中总汞和阴阳离子之间的相互关系,发现总汞和阴离子SO24-具有显著的相关性,与F-有一定的相关性,而与NO-3不具有相关性。由此初步判定,大气降水中的总汞主要来源于燃煤等人为释放源。

A study of the daily event precipitation in Guiyang was taken between July and September,2008.The average concentration of total Hg（THg） in daily event precipitation was 18 ng·L-1 with a range from 0.4 to 57.4 ng·L-1;the average concentration of methyl Hg（MeHg） in daily event precipitation was 0.07 ng·L-1,with a range from 0.02 to 0.2 ng·L-1.The main inorganic ions were SO2-4,NO-3,Ca2＋,NH4＋,and Mg2＋.The average concentrations of SO2-4 and NO-3 were 151 mol·L-1 and 145 mol·L-1,respectively.The average concentration of Ca2＋ was 123 mol·L-1 with a range from 3.7 mol·L-1 to 560 mol·L-1.The average concentrations of NH4＋ and Mg2＋ were 52.2 mol·L-1 and 20.4 mol·L-1,respectively.According to the relationships between the concentrations of THg and inorganic ions,we identified that the possible sources were fossil fuels burning.