Evaluation on Potential Ecological Risk of Heavy Metals in Soil of Yanjiao

The separate content of six types of heavy metals (Cd, Hg, Pb, As, Cu and Cr) in soil for Yanjiao area was evaluated in this article. Hakanson Potential ecological risk index was applied to analyze single factor potential ecological risk possibility and comprehensive ecological risk index regarding six types of pollution element in the soil. The result shows that the average value of potential ecological risk index sequences as Cd>Hg>Pb>Cu>As>Cr. The average ecological risk index of Cd is 44.90, which indicates that the soil ecological risk of the area is moderate. The average ecological risk index of other 5 types of heavy metals belongs to mild ecological risk grade. Based on the analysis of comprehensive ecological risk index, 15% of the sample points belong to the moderately ecological risk grade, and the rest 85% sample points belong to the lightly ecological risk grade. Among these elements, Cd and Hg contribute most to the ecological risk, and they are the major risk elements of the ecological risk.