揭西不同土地利用类型土壤重金属污染特征及风险评价

Characteristics and Risk Assessment of Heavy Metal Pollution in Different Land Use Types in Jiexi County

监测分析了以揭西县林地、农业用地和建设用地的331个土壤样品中的重金属含量,运用潜在生态风险指数法、健康风险指数法以及克里金插值法等对镍、锌、汞、砷、铜、镉、铅和铬的潜在生态风险和潜在健康风险进行研究。结果表明:汞超出《土壤破坏质量农用地土壤污染风险管控标准》风险筛选值,存在一定风险。研究区具有轻微潜在生态风险,汞和镉是主要生态风险因子,高值区主要分布在建设用地,综合潜在生态风险高值区主要分布在建设用地。成人和儿童的单项非致癌风险指数总和(HQ总)和总非致癌风险指数(HI)均<1,非致癌风险在可接受范围内。铬、砷和铅是主要非致癌贡献因子。砷对成人和儿童具有较高的致癌风险,是主要致癌风险因子。不同土地利用类型下成人和儿童总致癌风险指数(TCR)依次为农业用地>林地>建设用地。单项致癌风险指数总和(CR总)均为砷>镉>铬。

The heavy metals in soil of 331 samples from woodland,agricultural land and construction land in Jiexi County were analysed.The potential ecological risk and potential health risk of Ni,Zn,Hg,As,Cu,Cd,Pb and Cr were studied by using potential ecological risk index method,health risk index method and Kriging interpolation.The results showed that Hg exceeds the risk screening value of the Soil Envioronmental Quality Risk Control Standard for Soil Contamination of Agricultural Land,indicating the existence of certain risks.The study area belongs to slight potential ecological risks.Hg and Cd are the main influencing factors of potential ecological risks,and the high value areas of potential ecological risks of Cd and Hg are mainly distributed in the construction land.The high value areas of comprehensive potential ecological risk are mainly distributed in the construction land.The combined HQ and HI of adults and children are less than 1,which indicates that the non-carcinogenic health risks in the study area are acceptable.Cr,As and Pb are the major non-carcinogenic contributing factors.As shows higher carcinogenic risk for adults and children,which is the main carcinogenic risk factor.The TCR of adults and childern sorted by landuse type are agricultural land>woodland>construction land.The sum of individual carcinogenic risk index(total CR)are As>Cd>Cr.