三峡水库蓄水至135 m后坝前及香溪河水域溶解无机汞分布特征研究

根据2004年8月在长江三峡水库坝前及香溪河水域对溶解无机汞浓度观测结果,分析了三峡水库蓄水至135 m(135～139m)1a后溶解无机汞的变化,初步探讨了影响溶解无机汞变化的因素,估算了蓄水对河流输送汞的影响.结果表明,三峡库区干流河段平均浓度为22.7ng·L-1,范围为未检出至82.6ng·L-1.较高浓度区主要集中在20m以浅的水体;香溪河溶解无机汞浓度与干流基本相当,平均浓度为18.0ng·L-1,浓度范围为未检出至61.4ng·L-1.蓄水后,溶解无机汞浓度显著升高,数量可观的汞将随着泥沙的沉降而滞留库区,值得关注和进一步深入研究.

Distributions of Dissolved Inorganic Mercury in the Lower Part of the Three Gorges Reservoir

One year after the first filling stage of the Three Gorges Reservoir(TGR), dissolved inorganic mercury (Hg(DI)) was measured in August 2004. Concentration of Hg(DI) varied from undetection to 82.6 ng x L(-1) with average of 22.7 ng x L(-1). Stratification of Hg(DI) in the TGR was obviously. Concentrations of Hg(DI) were much higher in the layers above 20 m than in deep waters. Concentration of Hg(DI) in the Xiangxi River varied from undetection to 61.4 ng x L(-1) with average of 18.0 ng x L(-1). The Hg(DI) concentration increased obviously after the filling of the TGR. Large amount of Hg was retented with the deposition of sediment in the TGR. The retention of Hg by the TGR needs the further research.