淮河流域典型癌病高发区土壤和地下水重金属积累及健康风险

Health risk assessment of heavy metal accumulation in soil and groundwater in a typical high cancer incidence area of Huai River basin

分别采集淮河沿岸某癌病高发区土壤和地下水样品,分析和探讨了土壤和地下水重金属的含量、分布和季节变化,以及土壤和地下水重金属积累的生态与健康风险.结果表明,除Zn外,土壤和地下水重金属含量旱季均高于雨季,癌病高发村庄高于其他村庄,河流污染是沿岸土壤和地下水重金属积累的主要原因.除土壤Cd达到中度潜在生态风险外,土壤中其余重金属的潜在生态风险总体为轻微级.癌病高发村庄居民饮水中重金属致癌和非致癌健康风险明显高于其他村庄居民,均为其他村庄居民的2倍以上,其中,重金属非致癌健康风险达到93.09×10-10a-1,接近国际健康组织推荐的最大可忽略风险,重金属致癌健康风险达到27.82×10-5a-1,分别为ICRP和US EPA推荐的最大可接受风险的5倍和2倍以上.各种重金属中,Pb和Cr是主要的非致癌健康风险因子,Cr是主要的致癌健康风险因子.癌病高发村庄土壤和地下水重金属积累明显,存在较高的饮水重金属暴露健康风险.

Heavy metal concentrations of soil and groundwater samples are analyzed to investigate their sources and spatial and seasonal variations in soil and groundwater. The corresponding health risks are also evaluated. The results show that soil and groundwater concentrations of all six heavy metals except Zn in dry season are higher than those in rainy season. Soil and groundwater heavy metal concentration in cancer villages are much higher than that in other villages, which means that the polluted river are the main source of soil and groundwater heavy metal accumulation. The potential ecological risk of Cd in soil has reached the moderate level, while those of the other metals in soil are in the slight level. Health risks caused by carcinogens and noncarcinogens in drnking water for local residents in cancer villages are more than 2 times those for residents in other villages. The health risk caused by noncarcinogenic heavy metals reached 93.09x 10-1~ a-1, very close to the maximum negligible risk level recommended by some international health organizations. The health risk caused by carcinogenic heavy metals reached 27.82× 10^-5 a^-1 , more than 5 times and 2 times the maximum acceptable risk level recommended by ICRP and US EPA respectively. Pb and Cr are the main factors of noncarcinogenic health risk, while Cr is the main factor of carcinogenic health risk. A significant heavy metal accumulation in soil and groundwater has been discovered in cancer villages, and the residents suffer from severe health risk due to the heavy metal exposure through drinking water.