[Pollution Status and Migration of Mercury in the Sediments of Nansi Lake in Shandong Province].

The content of mercury and fractions were determined, in order to discuss the pollution situation and migration ability of mercury in inflow rivers and surface sediments of Nansi Lake. The average content of mercury in the sediments of the Nansi Lake was 0.046 mg · kg(-1), significantly higher than the environmental background values, which showed that Nansi Lake suffered from mercury pollution. Mercury in sediments existed mainly in the residual fraction, accounting for 65. 15%. The proportion of non-residual fractions was relatively small, in the order of organic bound fraction (30.61%), extractable fraction (2.93%), and Fe/Mn oxide (1.31%). The spatial change of non-residual fractions was that Weishan Lake and Nanyang Lake had higher non-residual mercury content than Zhaoyang Lake and Dushan Lake, and the non-residual mercury had a certain potential ecological harm on Weishan Lake and Nanyang Lake. From the horizontal view, the mercury content in the surface sediments of Nansi Lake had visible difference and the pollution degree was different among sub-lakes, so horizontal migration of mercury was obvious. Vertically, the mercury content showed a trend of increasing from the bottom to the top in core sediments, which might be associated with social and economic conditions in different periods.