Distribution and species of mercury in water and sediments from Xiangjiang River section flowing through Zhuzhou, Xiangtan, Changsha
湘江株潭长段江水(枯水期）和沉积物中汞的分布和形态

Total mercury content in water in dry season is (1.881 +/- 1.854) microg x L(-1) in Xiangjiang River section flowing through Zhuzhou, Xiangtan, Changsha. Mercury in water is mainly in the form of particle mercury. The maxima of total mercury and soluble mercury content discovered in Xiawan attenuating rapidly in section of Xiawan-Xiangtan but slowly in section of Xiangtan-Lake Dongting. The average content of total mercury in sediment is 0.846 mg x kg(-1) up to the highest level in rivers of China. The highest content of total mercury discovered in Xiawan is 3.268 mg x kg(-1) which far more exceeds III-level soil pollution norms of China. In the section of Xiawan-Majiahe mercury mainly exists in sediment and average content total mercury (in sediments) is 2.218 mg x kg(-1). With coming down by a big margin total mercury content is 0.442 mg x kg(-1) in section of Yijiawan-Juzizhou. In the downstream of Changsha total mercury attenuating slowly. The mercury average content in pore-water of sediments is 0.035 microg x L(-1). There is no significant correlation between pore-water mercury and total mercury. Mercury (in sediments) is mainly in the form of residue, soluble plus exchangeable ions,and organic matter bound that will become active and pollution again. From upstream to downstream the fraction bound to organic matter decreases, but residue mercury increases to a small extent that indicates the change of mercury form from the organic matter bounded to the form of residue. In the section analysis of mercury (in sediments), Hg reaches 65 cm deep. As the locations close to sediments top, total mercury content increases until the distance to sediment top is 30-25 cm.