长三角农业活动区农田土壤重金属风险评价

Risk assessment of heavy metals in farmland soils in an agricultural region in the Yangtze River Delta

为全面了解长江三角洲太湖平原典型农业活动区——太滆运河流域农田土壤重金属污染和风险状况,采集115个农田表层土壤样点,测定Cd、Cu、Zn、Ni、Pb、Cr、Hg和As的含量,并综合利用地累积指数法、潜在生态风险指数法和健康风险评价模型进行评估。结果表明:太滆运河流域农田土壤重金属含量均值满足食用农产品产地土壤环境质量要求,但Cd、Cu、Zn、Ni和Pb的含量均值超过了江苏省土壤背景值;农田土壤受到Cd和Pb的轻微污染,整体潜在生态风险较低;成人和儿童的非致癌风险(THI)均值分别为1.37和0.26,致癌风险(TCR)均值分别为1.42E-05和1.65E-05,整体致癌风险处于可接受水平,但儿童面临着明显的非致癌风险;Cr和As是农田土壤中最主要的健康风险因子。受人为活动的影响,成人和儿童的THI和TCR热点主要分布在太滆运河中游南部地区和下游地区。

We aimed to investigate the pollution and health risks of heavy metals in farmland soils in the Taige Canal,an agricultural region in the Yangtze River Delta,China.A total of 115 farmland soil samples were collected and the concentrations of Cd,Cu,Zn,Ni,Pb,Cr,Hg,and As were determined.The pollution characteristics and health risks of farmland soils were evaluated using geo-accumulation index,potential ecological risk index,and health risk assessment model.The results indicated that the average concentrations of heavy metals met the farmland environmental quality evaluation standards for edible agricultural products,but the mean concentrations of Cd,Cu,Zn,Ni,and Pb exceeded the baseline value for Jiangsu Province.Farmland soils were slightly contaminated with Cd and Pb and the potential ecological risk was low.The average non-carcinogenic risk(THI)for adults and children was 1.37 and 0.26,respectively.The average carcinogenic risk(TCR)for adults and children was 1.42E-05 and 1.65E-05,respectively.The carcinogenic risk in the study area was acceptable.However,children faced significant non-carcinogenic risks.Cr and As were the most important health risk related elements.These results demonstrated that hot spots for THI and TCR for adults and children were distributed in the middle reaches of the southern and downstream regions of the Taige Canal,locations with a high level of anthropogenic activities.