焚烧厂周边居民重金属污染物多途径暴露的健康风险

焚烧厂排放的重金属污染物会通过不同途径富集于周围环境介质中,如土壤、地表水、地下水、大气、蔬菜和家禽等.焚烧厂周边人群通过上述各种环境介质暴露于重金属,并产生累计的健康危害.然而目前研究很少关注人群通过多途径暴露的累计健康风险.本研究调查了一座典型医疗废物焚烧厂周边不同环境介质中的重金属含量,分析其与人体暴露关系,并计算了其不同途径暴露的健康风险及累计风险.结果表明重金属产生的非致癌风险大小As(298.1)Cr(35.4)Mn(14.0)Pb(7.0)Cu(2.3)Hg(1.9)Zn(1),致癌风险大小依次为As(1.32×10-2)Cr(1.31×10-2)10-5,均超过风险可接受水平;食用自产蔬菜是主要的暴露途径(贡献率为68%~92%)其次为自养家禽贡献率为10%左右.这说明区别于通常关注的通过土壤、水体、空气等介质暴露的风险相比,食用研究区周边的动植物产品导致的风险更大,需要引起重点关注;不确定分析结果表明考虑污染物浓度不确定条件下,场地健康风险大约有0.54~2.28倍的增加;风险管理研究表明通过截断食用本地蔬菜和家禽,除Cr的致癌风险外,其他重金属对厂区居民的健康风险水平会迅速降低至可接受水平.

Human health effects of heavy metals around an incineration plant through multi-media exposure

Emissions of wastes from incineration plant result in serious heavy metal pollution, leading to adverse human health effects through multi-media exposure. However, studies on the cumulative health risks of heavy metals through various media and pathways are limited. In this study, Nine types of metals, including manganese (Mn), zinc (Zn), lead (Pb), cadmium (Cd), copper (Cu), arsenic (As), chromium (Cr), mercury (Hg), and nickel (Ni) in PM₁₀, surface water, vegetable and soil were analyzed. The individual and aggregative risks of these metals through different media and pathways were then estimated on a field sampling and questionnaire-survey basis. The result indicated that the non-carcinogenic risk index produced by Zn, Hg, Cu, Pb, Mn, Cr and As were 1, 1.9, 2.3, 7.0, 14.0, 35.4 and 298.1, respectively, and the carcinogenic effect produced by Cr and As were 1.31×10^-2 and 1.32×10^-2, respectively, both of which exceeded the acceptable risk level. Contribution rate analysis showed that ingestion of local vegetable and chicken was the primary exposure route with contribution rate of 68%~92% and 10%. Furthermore, uncertainty analysis showed that the risk level would increase by 0.54~2.28 times if uncertainties were considered. It is suggested that, apart from Cr, cutting-off of the local food''s ingestion may be efficient to reduce the risk to an acceptable level.