金华市耕地土壤重金属来源解析及健康风险空间分异

Source identification and spatial differentiation of health risks of cultivated soil heavy metals in Jinhua City

不合理的人类活动可能会导致重金属元素在耕地土壤中富集,最终威胁到土壤环境质量、农产品安全及人类健康.以金华市耕地土壤重金属为研究对象,采集了209个表层土壤样品,测定了As、Cd、Cr、Cu、Hg、Ni、Pb、Zn的含量,并采用随机森林模型探讨了金华市耕地土壤重金属的来源.同时,结合人体健康风险评估模型、地统计分析和地理探测器对金华市耕地土壤重金属的健康风险及空间分异进行了评估.结果表明:(1)金华市耕地土壤中Cd、Cu、Hg、Pb和Zn元素的平均含量超过了浙江省土壤背景值,存在一定程度的积累;(2)随机森林模型分析表明,As、Cr和Ni主要为自然来源,Hg主要为大气沉降源,Pb和Zn主要为交通来源污染,Cu为农业和工业的共同污染;(3)健康风险结果显示,金华市耕地土壤重金属污染对儿童总的致癌风险已超过安全阈值,高值区主要出现在金华市的中西部和北部区域;(4)地理探测器结果显示,金华市相关管理部门有必要对耕地土壤的As、Pb、Cd、Cr和Cu元素实施分区管控,以降低其健康风险水平.

Irrational human activities may lead to the enrichment of soil heavy metals in farmland,ultimately threatening the quality of the soil environment,the safety of agricultural products and human health.In this study,209 surface soil samples were collected to determine the contents of As,Cd,Cr,Cu,Hg,Ni,Pb,and Zn in farmland soils in Jinhua City.The source of cultivated soil heavy metals in Jinhua City was explored by using random forest model,and the human health risk assessment model,geostatistical analysis and geodetector model were performed to analyses the spatial differentiation of health risks of farmland soil heavy metals in Jinhua City.The results showed that Cd,Cu,Hg,Pb and Zn in cultivated soil of Jinhua City exceeded the soil background value of Zhejiang Province and accumulated to a certain extent.The random forest model shows that As,Cr and Ni are mainly from natural sources,Hg is mainly from atmospheric deposition sources,Pb and Zn are mainly from traffic sources,and Cu is affected by agriculture and industrial.The health risk results show that the total carcinogenic risk of heavy metal pollution in cultivated land soil to children in Jinhua City has exceeded the safety threshold,and the high-value areas are mainly distributed in the Central,Western and Northern regions of Jinhua City.Geodetector model reveals that it is necessary for relevant local administrative departments to implement zoning control of As,Pb and Cd in farmland soil in order to reduce their health risk level.