拉萨市垃圾填埋场地下水水质的居民健康风险评价

Health risk assessment of groundwater quality in Lhasa landfill

对拉萨市垃圾填埋场地区地下水6个监测井中的Cr6+、As、Cd、Pb、NO-3-N、F-、Cl-指标采用美国环保局USEPA推荐的健康风险评价模型,按照不同人群进行健康风险评价.评价结果表明,通过暴露剂量计算,在饮水途径和皮肤接触途径下非致癌物暴露剂量一般高于致癌物暴露剂量;饮水途径暴露剂量高于皮肤接触途径下的暴露剂量.致癌污染物在饮水途径下风险值大于皮肤接触途径下的风险值,其中饮水途径下风险贡献为Cr6+>As>Cd,Cr6+风险值超过USEPA的最大可接受水平1×10-4;在皮肤接触途径下贡献为Cr6+>As>Cd,Cr6+的风险值超过瑞典环保局、荷兰建设环保局、英国皇家协会和IAEA最大可接受风险水平;非致癌风险的污染物贡献最大的是Cl-,其通过饮水暴露途径在成人中风险值高于瑞典环保局(1×10-6)、荷兰建设环保局(1×10-6)、英国皇家协会(1×10-6)和IAEA(5×10-7)最大可接受水平.因此,致癌物中Cr6+成为主要的致癌物,人们在饮水中要将其去除,起到预防癌症和减少患癌的几率.

In this paper, the indicators of Cr6+, As, Cd, Pb, NO3-N, F-, and Cl- in the 6 monitoring wells of groundwater in the Lhasa landfill site were evaluated through the health risk assessment model recommended by US Environmental Protection Agency′s(USEPA), which allows the pollutants to be assessed for health risks according to different populations. The results evaluation show that the exposure dose of non-carcinogens through drinking water route and skin contact route is generally higher than that of carcinogen exposure by exposure dose calculation;The exposure dose of drinking water route is higher than that of skin contact route. The risk value of carcinogenic pollutants through the drinking water route is greater than the risk value through the skin contact route. Specifically, the risk contribution under of drinking water route is Cr6+>As>Cd, and the risk value of Cr6+ exceeds 1×10-4 the maximum acceptable level of USEPA;In skin contact, the contribution is Cr6+>As>Cd, and the risk value of Cr6+ exceeds the maximum acceptable risk level of Swedish Environmental Protection Agency, Netherlands Construction Environmental Protection Agency, Royal Society and IAEA;Meanwhile, as the largest contributor to non-carcinogenic risk, the exposure of Cl- in adults through drinking water is higher than that of maximum acceptable level of Swedish Environmental Protection Agency(1×10-6), Netherlands Construction Environmental Protection Agency(1×10-6), Royal Society(1×10-6) and IAEA(5×10-7). Finally, it is clear that Cr6+ is a major carcinogen. Therefore, Cr6+ in drinking water needs to be removed in order to reduce the risk of cancer.