天台耕地土壤重金属污染及生态风险评价

Heavy metal pollution and ecological risk assessment of cultivated soils in Tiantai County of Zhejiang Province, China

文章通过在天台县耕地范围土壤中系统采集3588件表层土壤样品,分析As、Cd、Cr、Cu、Hg、Ni、Pb、Zn和Mn等9种元素质量比特征,采用皮尔逊相关系数分析确定重金属之间的相关性,并对土壤重金属污染程度、土壤重金属元素生态环境潜在危害及其对人类健康的影响进行评价。研究区范围重金属具有从中到高的变异系数,且分布极不均匀,As、Cd、Hg、Pb和Zn等土壤重金属空间异常主要受人为活动影响,通过主成分分析(principal component analysis,PCA)发现Cr-Ni-Cu、Cd-Pb-Zn分别具有同源组合特征。土壤污染评价结果发现,研究区主要污染元素为Cd和Ni。生态风险评价结果显示,各元素潜在生态环境危害以低风险为主,Cd、Hg和Ni元素存在少量中度及以上的潜在生态环境危害风险;然而,在重金属对人类健康的影响方面,As和Pb的影响最大,且儿童受影响风险超过成人。

Totally 3 588 surface soil samples(0 20 cm) were collected from the agricultural land in Tiantai County of Zhejiang Province,China,and contents of As,Cd,Cr,Cu,Hg,Ni,Pb,Zn and Mn were analyzed with different analytical techniques. The Pearson correlation coefficient analysis was made to study the relationship between the heavy metal elements,and the level of soil heavy metal pollution,potential ecological risk and hazards to human health were evaluated. Most of the heavy metal elements show poor spatial distribution with a medium or high variable coefficient. The spatial variations of As,Cd,Hg,Pb and Zn mainly result from human activities. Both the Pearson correlation coefficient analysis and the principal component analysis(PCA) indicate that Cr-Ni-Cu and Cd-Pb-Zn share the similar source of origin. It is found that Cd and Ni are the main pollutants in the study area. The ecological risk assessment shows that most of the heavy metal elements exhibit low risk to the environment,while Cd,Hg and Ni show a small quantity of moderate or serious risk to the environment. Furthermore,children are more prone to health hazards than adults with following order: As>Cr>Pb. In general,As and Pb exert prominent effects on the human health.