海南省主要农作物主产区土壤重金属含量分布及其健康风险评价

以海南省主要农作物主产区土壤为研究对象,对土壤中6种重（类）金属（Cr、Cd、Pb、Cu、Ni、As）的累积程度、潜在生态风险及通过经口摄入、呼吸摄入、皮肤接触3种不同暴露途径的健康风险进行评价。结果表明：与《土壤环境质量农用地土壤污染风险管控标准（试行）》（GB 15618-2018）中风险筛选值相比,Ni、Cd、Cr、Cu、Pb存在普遍的超值现象,其中Cr超筛选值的点位比例最高,为36.90%。单点位超风险筛选值标准最高的重金属为Cd,超标准3.07倍;6种重（类）金属均存在累积现象,除Cd外均只表现为轻微生态危害,Cd累积水平较高,部分地区还表现出中、强、很强生态危害;6种重金属非致癌健康风险均小于1,As、Ni、Cr的致癌风险在可接受水平内;与成人相比,对儿童的健康风险和致癌风险更大。

Distribution of Heavy Metal Contents in Soils of Main Crop Production Areas in Hainan and the Health Risk Assessment

The risk assessment in regards to the accumulation degree of heavy metals in soil (Cr, Cd, Pb, Cu, Ni and As), potential ecological hazards, and the health risks evolved from various exposure methods, including oral ingestion, inhalation and direct skin contact were conducted based on the soil samples obtained from the major crop growing areas in Hainan. The result revealed that in comparison with the risk thresholds suggested by the Soil Environmental Quality Risk Control Standard for Soil Contamination of Agricultural Land (Trial), the concentrations of Ni, Cd, Cr, Cu and Pb exceeded the thresholds in general whereas the highest exceeding which comes from Cd overtook the threshold by 307%; except for Cd, five heavy metals accumulated and incurred mild ecological hazards whereas Cd had a high accumulation degree and induced medium, critical or even severe ecological hazards in some particular areas. The indices for non-carcinogenic health risk of mentioned heavy metals were less than one; the carcinogenic health risks generated from As, Ni and Cr were acceptable. However, the health risks and carcinogenic risks were more severe for children than adults.