贵州东风水库沉积物间隙水中溶解态汞及甲基汞的分布特征及界面交换

Distribution and Sediment-water Exchange Flux of Dissolved Mercury and Methylmercury in Sediment Pore Waters in Dongfeng Reservoir,Guizhou Province,China

为弄清水库沉积物间隙水中汞及甲基汞的分布及扩散特征,于2009年春、夏两季对东风水库进行了采样,分别采用两次金汞齐-CVAFS法和蒸馏-乙基化结合GC-CVAFS法测定沉积物间隙水中溶解态(DHg)和甲基汞(DMeHg)浓度。结果表明夏季沉积物间隙水DHg浓度远高于春季,而DMeHg浓度却略低于春季;沉积物间隙水中DHg和DMeHg均有向上覆水体扩散的趋势,其夏季扩散通量高于春季;间隙水中DMeHg对上覆水体的贡献率大于DHg,最高可达30%,再次证明了沉积物间隙水中的DMeHg是其上覆水体的重要来源。

To understand the distribution and diffusion flux of dissolved mercury(DHg)and methylmercury(DMeHg),sediment pore water samples were collected from Dongfeng Reservoir(Guizhou Province,SW China)in spring and summer in2009.The collected samples were analyzed for DHg and MeHg concentrations.According to our data,the DHg concentrations in sediment pore waters collected in summer are significantly higher than that collected in spring,while the DMeHg showed opposite patterns with the DHg.Our study indicates the great potentials of emission of both DHg and DMeHg from the sediment pore waters to the reservoir,with much higher emission flux in summer compared that in spring.Compared with DHg,much larger proportion(up to 30%)of DMeHg can be emitted to the reservoir,indicating that sediment pore waters are important sources of MeHg to the reservoir.