江阴市典型河流沉积物重金属污染和风险评价

在摸清河流表层沉积物重金属(Cu、Zn、Pb、Cr、As)含量的基础上,利用综合污染指数和地累积指数评价其污染状况,计算潜在生态风险和人体健康风险。结果表明,江阴市河流沉积物已经受到重金属污染企业和城市径流双重影响,Cu、Zn、Pb峰值在汛期,As、Cr峰值在非汛期;污染负荷指数和地累积指数评价结果显示非汛期污染略轻,地累积指数法引入背景波动参数而使其评价结果较乐观。重金属潜在生态风险都为轻微风险级别;致癌风险处于10~(-3)数量级,非致癌风险数量级为10~(-7),致癌风险为人体健康风险主要承担者。潜在生态风险汛期高,人体健康风险非汛期高,这可能是重金属元素对致癌风险以及生态风险的贡献不同所致。

HEAVY METAL POLLUTION AND RISK ASSESSMENT OF TYPICAL RIVER SEDIMENTS IN JIANGYIN CITY

Based on the monitoring data of Cu,Zn,Pb,Cr,and As in sediments,pollution load index and geoaccumulation index,were used to assess heavy metals pollution.The aquatic ecological risk and human health risk were calculated by potential ecological risk index and health risk evaluation.The results showed that,river sediments in Jiangyin were affected by urban runoff and heavy metal polluted enterprises.Cu,Zn,and Pb levels peaked in flood season;As and Cu levels peaked in dry season.The consequences of pollution load index and geo -accumulation index showed that the pollution status declined slightly in dry season.Geo-accumulation index suggested a more optimistic estimate for heavy metal contamination,with the background fluctuation parameter included.The potential ecological risk was slight.The cancer risk was 10-3,while non-cancer risk was 10-7.So the cancer risk was a key contribution in human health risk.The potential risk was higher in flood season,while the human health risk was higher in dry season.This is probably because of different contribution rate of various heavy metal species during human health risk and potential ecological risk.