某典型农业活动区土壤与地下水有机氯农药污染健康风险评价

Health risk assessment of organochlorine pesticide pollution in soil and groundwater of a typical agricultural active area

以长江三角洲某农业活动区为目标研究区域,分别采集研究区0～20cm、20～40cm、40～60cm深度土壤样与浅层地下水样,分析该区有机氯农药六六六(HCHs)与滴滴涕(DDTs)在不同深度土壤至潜水含水层中的残留分布特征,并应用美国RBCA模型对研究区HCHs和DDTs进行健康风险评价.结果表明:在表层、第二层、第三层3个土层中β-HCH与DDE最大检出水平分别为50.28μg·kg-1与60.35μg·kg-1、30.25μg·kg-1与30.29μg·kg-1、3.54μg·kg-1与7.63μg·kg-1,检出率分别为76.5%与69.8%、75.2%与65.2%、40.3%与30.5%,而该区浅层地下水中农药残留未检出.基于RBCA健康风险评价模型计算该农业活动区中HCHs和DDTs累加致癌风险值为4.7×10-5,致癌风险较小;HCHs和DDTs的平均浓度值和最大浓度值对应的非致癌健康风险均未超出USEPA安全阈值1.0,风险较低.

This study focused on characterization of organochlorine pollutants in typical .agricultural activities of Yangtze River delta. The samples were collected from the soil in 0～20 cm, 20 ～40 cm, 40～60 cm depth and unconfined aquifer, and then the residual distribution characteristics of HCHs and DDTs at different depths of soil were analyzed. Finally, RBCA was applied to calculate the human health risk value of the area. The results indicated that the residual contents of β-HCH and DDE in surface layer, the second layer and the third layer were 50.28 μg·kg^-1 and 60.35 μg·kg^-1, 30.25 μg·kg^-1 and 30. 29μg·kg^-1, and 3.54 μg·kg^-1 and 7.63 μg·kg^-1, respectively. The maximum detection rates were 76.5 % and 69.8 % , 75.2% and 65.2% , and 40.3% and 30.5% respectively, while organochlorine pesticide residues were not detected in groundwater. The results from RBCA health risk evaluation model demonstrated that the HCHs and DDTs cumulative carcinogenic risk value in surface layer was 4.7 × 10^ -5, which was with less risk. HCHs and DDTs average concentration value and the maximum concentration value corresponding to non-carcinogenic health risk did not exceed the safety threshold 1. 0, indicating low non-cancer hazard health risk.