大宝山矿区某农田蔬菜重金属污染状况及健康风险评估

本研究通过大田试验，在对大宝山矿区某农田蔬菜中重金属As、Hg、Pb、Cd、Cr分析测试的基础之上，运用单因子污染指数法和综合污染指数法对该农田蔬菜的重金属污染状况进行评价；同时应用健康风险评估模型对人群经食物链途径长期食用本地产蔬菜可能产生的健康风险进行评估，以期为蔬菜的安全生产以及人体健康提出合理的意见和建议。结果表明，农田土壤中重金属As、Hg、Cr、Cd、Pb的含量分别是国家土壤环境质量二级标准的0.875、0.900、0.373、2.863倍和0.305倍，可以看出这5种重金属中只有Cd的含量超过了国家土壤环境质量二级标准。蔬菜重金属污染结果表明，蔬菜综合污染指数P_综范围在0.412～3.339，均值为1.155，属于轻度污染。蔬菜单因子污染指数P_As范围在0.013～0.085，均值为0.030；P_Hg范围在0.000～0.154，均值为0.076；P_Pb的范围在0.105～1.255，均值为0.343；P_Cd范围在0.563～4.609，均值为1.536；P_Cr范围在0.008～0.360，均值为0.091；可以看出该蔬菜主要受到Cd污染。蔬菜重金属污染的健康风险评估结果表明：17种蔬菜整体而言，Risk_总的平均值为3.50×10^-5 a^-1，表示该批蔬菜品种重金属污染情况对人体健康存在一定的风险，但风险尚可接受；Risk_T为3.50×10^-5 a^-1，表明该批蔬菜品种中致癌重金属对人体健康存在一定的风险，但风险尚可接受，且在致癌风险中Risk_Cd > Risk_Cr > Risk_As > Risk_Pb；HI_T为4.89×10^-10 a^-1，则表明该批蔬菜品种中非致癌重金属污染对人体健康存在的风险甚微，且在非致癌风险中HI_Pb>HI_Hg。

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 Risk_Cd > Risk_Cr > Risk_As > Risk_Pb; 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 HI_Pb>HI_Hg.