兰州市土壤重金属污染特征及其健康风险评价

Characteristics of heavy metals contamination in soil and health risk assessment in Lanzhou

目的探讨兰州市土壤重金属污染特征并进行健康风险评价。方法于2016年9月对兰州市城关区和榆中县居民生活区各设置13个采样点,共采集表层土壤样本60个,检测18种重金属含量;采用地累积指数评价污染程度,采用美国EPA推荐的模型进行健康风险评价。结果调查地区土壤Se和Hg达到中等-重污染水平,Cd也达到中等污染水平,城市土壤中Zn和Pb也达到轻-中等污染,除此之外,其它重金属均未造成污染。成人和儿童的多重金属暴露的综合非致癌风险分别为0.138和0.917,综合致癌风险分别为1.75×10-6(As的经口暴露:1.51×10-6)和5.97×10-7。结论应进一步加强当地土壤重金属污染的防控,尤其关注土壤As的污染。

Objective To understand the characteristics of heavy metals contamination in soil and its health risk assessment in Lanzhou.Methods During September 2016,a total of 60 surface soil samples were collected from 13 sampling sites in residential area Chengguan district and Yuzhong county of Lanzhou,and 18 heavy metals were determined and the contamination level was evaluated by using geological accumulation index method and health risk assessment was conducted with the model recommended by USEPA.Results The contents of Se,Hg in soil reached the moderate-heavy contamination level,Cd was at the moderate contamination level,Zn and Pb in urban were at the light-moderate contamination level,other heavy metals were at non-contamination levels.The total non-carcinogenic risks caused by exposure to multi-metals were0.138 for adults and 0.917 for children respectively.Additionally,the total carcinogenic health risks were 1.75×10-6(oral exposure to As:1.51×10-6)for adults and 5.97×10-7 for children respectively.Conclusion Control and prevention of heavy metals contamination in soil,especially arsenic,in the investigated area in Lanzhou should be strengthened further.