锌冶炼区菜地土壤和蔬菜重金属污染状况及风险评价

对黔西北地区某典型锌冶炼区菜地土壤和主要蔬菜进行取样调查，测定了土壤和蔬菜可食用部分Pb、Cd、Zn、Cu、As、Ni 6种重金属的含量，采用单项污染指数和综合污染指数法评价了土壤和蔬菜中重金属的污染状况，并分别采用潜在生态风险指数（RI）和目标危险系数法（THQ）评价了菜地土壤重金属污染的潜在生态风险和蔬菜中重金属对成人和青少年儿童的健康风险.结果表明，该区域菜地土壤已受到重金属的重度污染，且以Cd对综合指数的贡献最大，土壤Cd存在极强生态风险，研究区处于轻微、中等、强和很强的生态风险程度的采样点比例分别为2.0%、14.3%、35.7%和48.0%；在所采集的蔬菜样本中，土豆处于重度污染水平，芸豆处于中度污染水平；复合重金属健康风险指数评价结果表明，食用研究区域蔬菜对成人和青少年儿童健康产生负面影响的可能性很大.

Contamination and risk of heavy metals in soils and vegetables from zinc smelting area

The concentration of Pb, Cd, Zn, Cu, As and Ni in soils and dominant vegetables were determined based on the soil and vegetable samples collected from a representative zinc-smelting region in Northwest of Guizhou province. Both single factor pollution index and comprehensive pollution index methods were used to assess the concentration of heavy metals in soils and vegetables, and their potential ecological risks and health risks to adults and adolescents were also analyzed by the potential ecological risk index (RI) and target hazard quotient (THQ) methods. The results showed that the soils in the zinc-smelting area were contaminated by heavy metals and Cd contributed the most to the integrated pollution index; high ecological risks were imposed by Cd and there were 2.04%, 14.3%, 35.7% and 48.0% of sample sites in each category, decided according to the potential ecological risk index, of low, medium, high and extremely high risk, respectively. Among vegetable samples, the potatoes were heavily polluted and kidney beans were moderately polluted. Moreover, the comprehensive health risk index analysis suggested that the eating of vegetables grown in sample areas could cause serious potential health risks for adults and adolescents.