贵州洪家渡水库水体不同形态汞的分布特征

Distribution of different mercury forms of Hongjiadu Reservoir from Guizhou Province

通过分析贵州省乌江流域新建的洪家渡水库水体不同形态汞的浓度,探讨了水库水体各形态汞的分布特征,旨在进一步弄清新修建的水库水体汞的甲基化过程。结果表明,洪家渡水库总汞（THg）浓度变化范围在0.32~6.75 ng.L-1;溶解态汞（DHg）浓度变化范围在0.23~2.27 ng.L-1;颗粒态（PHg）汞浓度变化范围在0.03~4.51 ng.L-1;总甲基汞（TMeHg）浓度变化范围在0.04~0.18 ng.L-1;溶解态甲基汞（DMeHg）浓度变化范围在0.02~0.08 ng.L-1;颗粒态甲基汞（PMeHg）浓度变化范围在0.01~0.13 ng.L-1。洪家渡水库水体不同形态汞存在着季节性变化,水体THg、DHg和PHg的季节变化表现为夏、秋季大于春、冬季;水体TMeHg、DMeHg和PMeHg的季节变化表现为春、夏季大于秋、冬季。在空间上,水体甲基汞含量从表层到底层表现无规律性的增加趋势,从上游到下游的浓度也无明显的变化,与北美欧洲新建水库水体甲基汞浓度（0.01~6.6 ng.L-1）进行比较,发现洪家渡水库水体甲基汞浓度明显偏低,以上结果说明洪家渡水库水体没有显著的汞甲基化作用,这与乌江流域淹没土壤的贫瘠、有机质含量偏低有关。

We studied the concentration of different mercury（Hg） species in Hongjiadu Reservoir within Guizhou Province,China,and discussed the distribution and speciation of different Hg species and the mechanism of methylmercury（MeHg） production in the water column in Hongjiadu Reservoir.The results showed that total Hg（THg） concentration ranged from 0.32 to 6.75 ng·L-1,dissolved Hg（DHg） concentration was between 0.23 and 2.27 ng·L-1,particulate Hg（PHg） concentration ranged from 0.03 to 4.51 ng·L-1,total MeHg（TMeHg） concentration ranged from 0.04 to 0.18 ng·L-1,dissolved MeHg（DMeHg） concentration ranged from 0.02 to 0.08 ng·L-1,particulate MeHg（PMeHg） concentration ranged from 0.01 to 0.13 ng·L-1.The concentrations of different Hg species changed with season.In summer and autumn,THg,DHg and PHg concentrations were significantly higher than in spring and winter.In spring and summer,TMeHg,DMeHg and PMeHg concentrations were significantly higher than in autumn and winter.Spatially,total MeHg levels did not increase with depth in water column,nor did MeHg levels increase spatially,from upstream to the dam.Total MeHg concentration in water column of Hongjiadu Reservoir was much lower than those reported（range： 0.01-6.6 ng·L-1） in North America and Europe.Hongjiadu Reservoir did not show the obvious characteristics of Hg methylation in water column,which was correlated with the low levels of nutrient and organic matter in flooded soil.