铅锌矿区玉米中重金属污染特征及健康风险评价

Heavy Metal Contamination and Health Risk Assessment of Corn Grains from a Pb-Zn Mining Area

以西南某铅锌矿区为研究区域,测定了92份玉米样品中Pb、Zn、Cd、Cr和Ni的含量,开展了矿区玉米籽粒中重金属污染特征及健康风险研究.应用单因子污染指数和内梅罗综合污染指数分析了重金属在玉米中的污染状况,采用健康风险评价模型评价了重金属对人体健康造成的风险,同时利用主成分分析法解析了重金属的主要来源.结果表明,玉米籽粒中Pb、Zn、Cd、Cr和Ni的平均含量分别为0.30、23.75、0.21、1.33和1.15 mg·kg^-1;除重金属Zn外,其他4种重金属均超过我国食品卫生标准限值,研究区玉米籽粒中Pb、Cd、Cr和Ni的综合污染指数范围介于4.32~9.07之间,均属于重度污染,Zn的综合污染指数小于1;重金属通过玉米籽粒摄入引起的复合重金属污染对成人和儿童均存在健康风险,且对儿童造成的健康风险高于成人.玉米籽粒中5种重金属可以由2个主成分来反映,第一主成分主要支配Pb、Cd、Cr和Ni的来源,第二主成分支配Zn的来源.玉米籽粒重金属含量与土壤重金属含量之间没有明显相关性.

A total of 92 corn grain samples,around the Pb-Zn mining area in Southwest China,were collected to evaluate the contamination and health risk of heavy metals.Heavy metals including Pb,Zn,Cd,Cr,and Ni in samples were analyzed.A single factor pollution index and comprehensive pollution index were calculated to assess the quality of corn grains.The potential health risks to adults and children due to the intake of these heavy metals through consumption of crops were evaluated using the health risk index.The results showed that the average contents of Pb,Zn,Cd,Cr,and Ni in corn grains were 0.30,23.75,0.21,1.33,and 1.15 mg·kg^-1,respectively,Among the metals,the content of Zn,Pb,Cd,Cr,and Ni exceeded the national food hygiene standards.The Nemero index of Pb,Cd,Cr,and Ni ranged from 4.32 to 9.07,indicating an extremely high level,whereas the contamination of Zn reached an alarming level.The assessment results of the comprehensive health risk index for the corn grains indicated that the contamination of heavy metals poses health risks to adults and children by food ingestion;moreover,the children were more sensitive to various heavy metals than the adults.Principle component analysis revealed that the first main component dominated the sources of Pb,Cd,Cr,and Ni,while the second main component,Zn,might have originated from sources different from the other heavy metals.Positive correlations were not observed between the heavy metals in corns and soils.