Distribution Characteristics and Risk Evaluation of Cd and Hg in Sediments on the Zhenjiang Ancient Canal river

摘要

The purpose of this paper is to study the speciation and contents of two types of heavy metals (Cd and Hg) in the sediments in Power Bridge (D1) and Nanshui Bridge (N2) in the middle part of the Ancient Canal in Zhenjiang. The relationship between the speciation of these heavy metals and their environmental factors were described. Morerover, the ecological hazard and trace to the source of these two types of heavy metals was also determined preliminarily. The results showed that (1) the main heavy metal contamination in the sediments of Power Bridge and Nanshui Bridge is Cd, and the average value is 20 mg/Kg, 17 mg/Kg, respectively, which were higher than environmental background value;(2) The peak value of Hg and Cd were near equilibrium in the 0.1-0.2m depth of Sediments; (3) Calculate the individual potential ecological risk index in the sediments of heavy metal element of two sample points both quantity of contents are Cd>Hg. And visible ecological threat of heavy metals were from Cd. After removing the Cd value, the RI value showed that ecological harm index basically below mild ecological harm degree.