Heavy Metals Pollution in Vegetables Grown on Some Farmlands Around Dabaoshan Mine and Its Healthy Risk Evaluation

This study used the approaches of the single factor pollution index and the comprehensive factor pollution index to evaluate the heavy-metals pollution in vegetables by analyzing the data of the heavy metals(As, Hg, Cr, Cd, Pb) contents in vegetables grown around the area of Dabaoshan mine. Synchronously considering the potential healthy risks of the local people from long-term consumption of vegetables, we also applied the health risk assessment model to evaluate the health risks of vegetables polluted by heavy metals. The results showed that the contents of As, Hg, Cr, Cd, Pb in this farmland soil were 0.875, 0.900, 0.373, 2.863, 0.305 times as the threshold values from the national second-grading standard of environmental quality assessment for soils respectively, suggesting that only Cd content in soil was beyond the standard level. The comprehensive pollution index of heavy metal pollution in vegetables ranged from 0.412 to 3.339 with the mean value being of 1.155, which belonged to the level of light pollution. The single factor pollution indexes of As, Hg, Pb, Cd and Cr were 0.412~3.339, 0.000~0.154, 0.105~1.255, 0.563~4.609 and 0.008~0.360 respectively, and the means of these five heavy metals were 0.030, 0.076, 0.343, 1.536 and 0.091 respectively, indicating that the pollution of vegetables was mainly suffered from Cd. Additionally, results from the data of health risk assessment of the heavy metal pollution in 17 vegetables showed:the mean of the total risk was 3.50×10-5 a-1, suggesting that the situation of heavy metal pollution in vegetable varieties had a certain risk to human health, but the risk was acceptable; the mean of the carcinogenic risk for human health was 3.50×10-5 a-1, this meant that the situation of heavy metal pollution in vegetable varieties had a certain risk to human health of the carcinogenic risk, but was acceptable with a degree order of the carcinogenic risk was RiskCd > RiskCr > RiskAs > RiskPb; the total value from the non-carcinogenic risk was 4.89×10-10 a-1, indicating that the non-carcinogenic risk showed little effects on human health with a order of HIPb>HIHg