浙江某地区耕地土壤重金属污染特征及生态风险评价

Characteristics and ecological risk assessment of heavy metal pollution from a cultivated area in Zhejiang Province

为评估耕地土壤表层重金属污染特征、生态风险水平以及来源,取浙江省某一耕地区域作为研究对象,测定0~50 cm表层土壤的Cu、Ni、Cd、Pb、Hg、As 6种元素含量,采用单因子污染指数和内梅罗指数法分析重金属污染特征,利用潜在生态风险指数法分析重金属生态风险水平,在相关性分析的基础上采用绝对因子得分-多元线性回归(APCS-MLR)受体模型定量解析重金属污染来源。结果表明:25%样品的镍含量、37.5%样品的镉含量以及12.5%样品的汞含量超过土壤背景值,其余元素均低于土壤背景值;整体区域呈现轻度污染及以下状态,Ni和Hg是重要污染贡献者;土壤整体处于轻度生态风险水平,所有元素属于轻度生态风险水平,Cd是引起风险的主要因子;As、Cd、Cu可能来源于自然成因,Hg可能来源于农业活动;Pb和Ni可能来源于交通活动。

To assess the characteristics of heavy metal pollution ecological risk level and source in the topsoil of cultivated land a cultivated area in Zhejiang Province was selected as the study area to detect the content of Cu Ni Cd Pb Hg As in the topsoil from 0 to 50 cm.The single factor pollution index and the Narome Index method were used to analyze the characteristics of heavy metal pollution and the Potential Ecological Risk Assessment method was conducted to analyze the level of ecological risk of heavy metals.Based on correlation analysis the Absolute Principal Com-ponent Scores-Multiple Linear Regression APCS-MLR receptor model was applied to quantita-tively analyze the sources of heavy metal pollution.The results showed that the nickel content of 25%of the samples the cadmium content of 37.5%of the samples and the mercury content of 12.5%of the samples exceeded the soil background values while the remaining elements were be-low the soil background values The overall region is slightly polluted or below with Ni and Hg being important contributors to pollution The overall soil is at a mild ecological risk level with all elements belonging to a mild ecological risk level and Cd is the main factor causing the risk As Cd and Cu may originate from natural causes while Hg may originate from agricultural activities Pb and Ni may originate from traffic-related sources.