[Distribution of heavy metals in Xiangsi River Valley of Tongling, China].

The Xiangsi River valley was selected to study the distribution of heavy metals in mining area. Waste rocks, soils, sediments and waters of Xiangsi River valley were sampled. The concentrations of Cu, Pb, Zn, Cd, Cr, As and Hg were analyzed. The possibility of generating acid drainage of the waste rocks was studied. Meanwhile, the speciation of Pb and Cr in waste rocks was analyzed by the five-step sequential chemical extract method developed by Fŏrtsner. And then the distribution of heavy metals in various samples was summarized, and the ecological risk of heavy metals in mining area was discussed. The results indicated that the waste rocks of Fenghuangshan copper mine upriver barely generated acid mine drainage (AMD). But the waste rocks of Xinqiao pyrite mine in the middle area generated AMD. The content of sulfide mineral rich of heavy metals was lower and the content of CaO was higher in the waste rocks of Fenghuangshan copper mine, resulting in the different AMD generation ability. The contents of heavy metals in waste rocks were higher, and the deoxidization of Pb and Cr was positively correlated with their concentrations in waste rocks. The results indicated that heavy metals in waste rocks would be most likely dissolved in AMD and then contaminate the environment. There was obvious regularity in the distributions of heavy metals in soils, sediments and waters of Xiangsi river valley. The concentrations of heavy metals upriver were lower than those of corresponding national standards and elements background values. But there was obvious heavy metal contamination in the middle area. It was shown that the mining activities of Xinqiao pyrite mine in the middle area had ecological harm to the surrounding environment. And mining enterprises should pay attention to the emissions of mining wastes and the treatment of AMD.