乌江流域大气降雨中不同形态汞的时空分布

Temporal and spatial distribution of different mercury species in precipitation of Wujiang River Basin

2006年1-12月测定了乌江流域5个水库库区大气降雨中不同形态汞的浓度．结果表明，总汞、溶解态汞、颗粒态汞、活性汞、甲基汞的浓度范围分别为7．49-149．13ng·L^-1、1．23～10．02ng·L^-1、5．76-141．92ng·L^-1、0．56～2．94ng·L^-1、0．082～0．821ng·L^-1．降雨中颗粒态汞为主要形态，约占总汞比例的67．6％～96．1％（平均87％），活性汞、甲基汞占总汞的比例分别为5．1％和0．68％．除活性汞外，其它形态汞的浓度存在明显的季节变化趋势，冬春季的浓度明显高于夏秋季，而不同形态汞的空间分布特征不明显．降雨中汞的浓度主要受降雨量及燃煤等人为活动的影响．

Concentrations of mercury （Hg） species were measured in precipitation collected from five sites in the Wujiang River between January and December, 2006. The concentrations of total Hg （THg） ranged from 7.49 to 149. 13 ng·L^-1 , dissolved Hg （DHg） from 1.23 to 10.02 ng·L^-1 , particulate Hg （Prig） from 5.76 to 141.92 ng·L^-1 , reactive Hg （RHg） from 0.56 to 2.94 ng·L^-1 , and methylmercury （MeHg） from 0.082 to 0.821 ng·L^-1. The particulate fraction, which accounted for 67.6% -96.1% with an average of 87% of the total Hg, was dominant among the different Hg species. The ratios of RHg and MeHg were 5. 1% and 0.68% , respectively. Concentrations of THg, DHg, PHg, and MeHg in samples collected in winter and spring were significantly higher than those found in summer and autumn, however, no significant spatial differences were obtained among Hg species in samples from five sites. Mercury levels in the precipitation were mainly affected by the amount of rainfall, coal combustion, and other human activities.