大宝山矿区重金属污染对人体健康风险的研究

Heavy metal contamination and health risk assessment in Dabao Mountain,China

以广东省大宝山重金属污染矿区癌症高发村上坝为研究区域,测定了上坝村31户饮用井水,13种58个蔬菜样品,26户大米样品中Pb、Zn、Cd、Cu的含量以及人体尿样、血样中Cd的含量.系统地评价了通过饮食途径(井水、蔬菜和大米)重金属暴露接触对人体的健康风险.研究结果表明,上坝污染区31户井水中分别有12口井水的Zn和14口井水的Cd含量超过生活饮用水水质标准;Pb、Zn、Cd在蔬菜中的含量分别为国家蔬菜卫生标准限值的4.0、1.1、5.6倍,在大米中的含量为国家粮食卫生标准限值的7.0、3.4、2.9倍.重金属暴露接触对人体健康风险评价结果表明,通过大米摄入的Pb、Zn、Cd、Cu的THQ(Target hazard quotients)靶标危害系数均大于1,饮食摄入重金属途径中大米对人体健康已构成巨大的潜在风险,蔬菜中Cd和Pb也具有潜在风险;饮用井水中几种重金属的THQ值均小于1,说明井水中重金属对污染区居民健康风险很低,因而Pb、Cd和Zn通过大米的摄入是造成当地居民健康风险的主要原因.重金属暴露接触对儿童的健康风险高于成年人.上坝村居民血Pb负荷水平远低于国家卫生部Pb接触限值,但尿Cd和血Cd含量平均值分别为3.41μg·g-1(肌酐Creatine,Cr)和4.69μg·L-1,略高于国内外其它非污染地区的平均水平.

The food chain is the main pathway of heavy metals transfer from the environment to humans. This study focused on the acid mine contamination and health effects of Ph, Zn, Cd, and Cu in Shangha village, Guangdong province, China. The results showed that the mean concentrations of Ph, Zn, Cd and Cu were 0.80, 22.45, 0.28 and 1.07 mg·kg^-1 in vegetables and 2.81, 60.83, 0.58 and 6.54 mg·kg^-1 in rice, respectively. Further, Ph, Zn and Cd concentrations in rice were 7.2, 3.4, 2.9 times greater than the tolerance level. The health risks associated with these heavy metals were assessed based on the Target Hazard Quotients （THQs） , which can be derived from concentrations of heavy metals in drinking water, rice and vegetables consumed by the inhabitants. The THQ of Pb, Zn, Cd, and Cu in rice were greater than 1. THQ values indicated that consumption of both rice and vegetables would lead to high potential health risks especially for children. The THQs results from drinking water consumption showed that the health risk for humans was low. The Cd concentrations were 4.69 μg·L^-1 and 3.41 μg·g^-1 creatine in blood and urine, respectively. The results showed that Cd and Ph were the most important metals affecting the inhabitants in this contaminated area. The health risk from Cd and Pb was slightly more than that of uncontaminated areas in other countries and districts.