Ecological Risk Evaluation Of Heavy Metals In Soil At Environmental Health Risk Region Near Tuohe River And Kuihe Riverin Yongqiao District

Objective The environmental health risk of the residents living in the sub-branch of Huai River has been concerned for many years because of the severe water pollution. Detecting the content of metals in the soil around Kuihe River and Tuohe River and evaluating the potential ecological risk may provide basic information for local environmental management.Methods Nine villages were selected as study area which locates within 2 000 m away from Kuihe River and Tuohe River in Yongqiao District, Suzhou city. Soil samples were collected at sites that are 500 m, 1 000 m, 2 000 m away from each river, respectively. ICP-MS was used to detect the content of As, Cd, Cr, Cu, Ni, Pb and Zn in the samples. Single-factor method, Nemerow pollution index method and potential ecological risk index method were used to evaluate level of the soil contamination and potential ecological risk.Results In all 27 samples, the exceeding rates of Cd, As and Cr were both 100%, the exceeding rates of Cu, Zn, Ni and Pb were 96.2%, 85.2%, 74.1% and 59.3%, respectively. The contents of Pb were all below the standards. The concentration of As, Cd, Cr, Ni, Cu, Zn concentrations were all exceeded their background values. The results from Single-factor method showed that the pollution level of cadmium was moderate, the pollution levels of arsenic and chromium were light, and the pollution levels of Ni, Pb, Cu, Zn were slight. The Nemerow pollution index of the soil surrounding Kuihe River and Tuohe River was 3.1, indicating the soil was severely polluted. The ecological risk value of the soil was 166.8 which demonstrated the strong ecological risk of this field.Conclusion The investigation indicated that the contents of heavy metals in the soil are high in the study area and the ecological risk is not accep Tab. Effective treatment should be conducted to reduce the content of heavy metals in the soil.