浙江省典型农田土壤重金属污染及生态风险评价

Heavy Metals in Typical Farmland Soils of Zhejiang Province: Levels, Sources and Ecological Risks

浙江是中国经济社会发展最快的省份之一,人类活动对土壤环境扰动强烈。为系统了解浙江省典型农田土壤重金属的污染水平、空间分布特征及生态风险,采集并分析了67个代表性农田土壤表层样品中的8种重金属元素(As、Cd、Cr、Cu、Mn、Ni、Pb和Zn),采用主成分分析法进行来源解析,采用污染负荷指数(PLI)、潜在生态风险指数(RI)和生态风险预警指数(IER)对农田土壤重金属污染与环境风险进行评价。结果表明,浙江省典型农田土壤环境重金属为轻度污染状态,研究区域农田土壤中的Cr、Ni和As处于轻微污染水平;Pb、Hg、Cu和Zn处于轻度污染水平;Cd处于重度污染水平,应作为优先控制元素。研究区域农田土壤Cr、Cu、Zn和Ni的来源主要受自然因素控制,Cd和Hg主要来源于工农业生产等人为活动,Pb主要来源于交通源。浙江省的金华市义乌、绍兴市诸暨、绍兴市嵊州、丽水市缙云县岩沿村应作为浙江省典型农田土壤的优先控制区域。浙江省典型农田土壤重金属环境存在轻微生态风险。

Zhejiang is one of the provinces with the fastest economic and social development in China, the soil environment is strongly disturbed by human activities. In order to systematically understand the levels, sources and ecological risks of heavy metals in typical farmland soils of Zhejiang Province, 67 representative soil samples were collected and eight heavy metals (As, Cd, Cr, Cu, Mn, Ni, Pb and Zn) were determined. The pollution load index (PLI), potential ecological risk index (RI) and ecological risk warning index (IER) was used to evaluate heavy metal pollution and ecological risks. The results showed that farmland soils were slightly polluted by Cr, Ni, As, Pb, Hg, Cu and Zn, which were seriously polluted by Cd, so Cd was suggested to be the priority control pollutant. Principal Component Analysis (PCA) was used to analyze their sources, the result showed that Cr, Cu, Zn and Ni in farmland soils mainly came from natural sources, Cd and Hg mainly originated from artificial activities such as industrial and agricultural production, while Pb mainly came from traffic sources. According to the results of spatial distribution analysis, Yiwu in Jinhua city, Zhuji in Shaoxing city, Shengzhou in Shaoxing city, and Yanyan village in Jinyun county of Lishui city was suggested to be the priority control regions. There were slight ecological risks resulted by heavy metals pollution in the farmland soils of Zhejiang province.