铅锌尾矿库土壤和蔬菜重金属污染特征及健康风险评价

研究调查了洛阳市西南部某铅锌尾矿库山林区、生活区、农田区表层土壤和农田区蔬菜中8种重金属含量，采用污染指数、潜在生态危害及健康风险进行评价.结果表明：农田区Pb、Zn、Cr、Cd和As重金属平均含量均高于土壤风险筛选值；蔬菜中重金属平均含量均超过食品污染物限量.各功能区内梅罗综合污染指数（PN）和非致癌总风险指数（HI）依次为农田区 > 3 > 生活区 > 山林区 > 2、农田区 > 1 > 山林区 > 生活区 > 0.5.其中，HI_Pb、HI_Cr、HI_As之和分别占成人、儿童致癌总风险HI的43%、58%.各功能区As对单项非致癌风险（HQ）作用明显，分别占成人HQ、儿童HQ的45%、35%；52%、41%；23%、17%.各功能区致癌风险总指数（TCR）均表现为农田区>山林区>生活区>10^-6.蔬菜中As对HI作用明显，均占对成人HI、儿童HI的贡献相同，均为55%、64%、94%和60%.4种蔬菜中重金属致癌与非致癌风险对居民作用依次为白菜 > 花椰菜 > 萝卜 > 甜菜.因此，尾矿库周边土壤及蔬菜重金属污染对周边生态环境和居民健康生活构成严重威胁.

Heavy metal pollution characteristics and health risk evaluation of soil and vegetables in various functional areas of lead-zinc tailings pond

The heavy metals on a lead-zinc tailings area (including mountain forest, living area, farmland, and vegetable field), southwest of Luoyang, Henan, were investigated, and the subsequent evaluation on the pollution index, potential ecological hazards, and health risks were conducted in the present study. Results indicated that the contents of Pb, Zn, Cr, Cd and As in the farmland were higher than the Soil Risk Screening Value. Meanwhile, the content of heavy metals (including Pb, Zn, Cu, Cr,Cd, Ni, Hg and As) in the sampled vegetables exceeded the Critical Food-safety Threshold. The Mero comprehensive pollution index (PN) and non-carcinogenic total risk index (HI) in each functional area followed the order:farmland area > 3 > living area > mountain forest area > 2, and farmland area > 1 > mountain forest area > living area > 0.5, respectively. The sum of HI_Pb,HI_Cr and HI_As accounted for 43% and 58% of the total cancer risk in adults and children, respectively. Arsenic levels in mountain forest, living area, and farmland have significant effects on the single non-carcinogenic risk (HQ), accounting for 45%, 52% and 23% of adult HQ, and 35%, 41%, 17% of pediatric HQ, respectively. The total cancer risk index (TCR) of each functional area was found to follow the order:farmland > mountain forest > living area > 10^-6. Meanwhile, Arsenic level has a significant effect on vegetables HI, accounting for 55%, 64%, 94% and 60% of adult and pediatric HI, respectively. The carcinogenic and non-carcinogenic risk of heavy metals in four vegetables followed the order of cabbage > cauliflower > radish > beet. Therefore, the heavy metal pollution of soils and vegetables in the studied tailings area poses a serious threat to the surrounding ecological environment and residents'' healthy.