电镀企业周边大气颗粒物PM_(2.5)、PM_(10)和TSP中重金属分布特征及健康风险评价

以东莞市5个镇区为研究对象,采集电镀企业周边大气样品,分析了样品中重金属(包括As、Co、Cd、Cr、Cu、Mn、Ni、Pb、Sb、V、Zn和Hg)的含量分布,使用富集因子(enrich factor)、地累积指数(index of geoaccumulation)、Hakanson法和美国国家环境保护局(US EPA)的人体暴露健康风险评价模型,对PM_(2.5)、PM_(10)、总悬浮颗粒物(TSP)中重金属进行人体健康风险评价。结果表明,PM_(2.5)、PM_(10)和TSP中As、Cd和Cr平均浓度皆超标。Cr、Ni和V元素在3种颗粒物中非富集,主要为自然源;As、Co、Cu、Pb和Zn,可能来源于自然源和叠加的工业污染。Cd、Hg和Sb浓度受人为污染影响严重。Cd、Sb、Cu、Zn、Pb为生物可利用元素(K>0.6),在环境中的可迁移性高且易于被生物体和人体吸收。Mn元素的非致癌风险值较其他重金属要高1~4个数量级,且儿童的非致癌暴露风险值HQ均高于成人的。3种颗粒物中重金属元素通过呼吸吸入途径产生的非致癌风险HI值均高于人体可接受的上限1.0,其主要贡献来源于Mn的影响,研究区非致癌风险较为严重。除PM_(10)中Co元素和TSP中Co、Cr的成人致癌风险CR值大于10-4之外,其余大部分重金属元素通过呼吸途径产生的致癌风险CR值均在可接受范围之内,此外,3种颗粒物中的成人的致癌暴露风险值CRT均高于儿童的CRT值,并且除了PM_(2.5)中儿童的重金属致癌暴露风险CRT值(4.70E-05)低于人体可接受范围的上限(10-4),其余CRT值均高于10-4,致癌风险较为严重。

Distrubution Characteristics of Heavy Metals in PM2.5, PM10 and TSP around Electroplating Factories and the Health Risk Assessment

This study aimed to investigate the pollution level and human health risk of heavy metals in PM_2.5, PM₁₀ and total suspended particulate (TSP) around electroplating factories. Samples were collected from five towns of Dongguan City to measure 12 kinds of heavy metals (As, Co, Cd, Cr, Cu, Mn, Ni, Pb, Sb, V, Zn, and Hg). Enrichment factor, geoaccumulation index, Hakanson and US EPA risk assessment guidance for superfund were carried out respectively. Our results showed that concentrations of As, Cd and Cr in PM_2.5, PM₁₀ and TSP were higher than their limited values of the corresponding quality standards. Cr, Ni and V in PM_2.5, PM₁₀ and TSP mainly orinated from the natural source. As, Co, Cu, Pb, and Zn probably came from natural source with addition of industrial pollution. Concentrations of Cd, Hg and Sb were mainly derived from human pollution. Cd, Sb, Cu, Zn and Pb as bioavailable elements (K > 0.6), showed high mobility in the environment, which could be rapidly absorbed by organism and human body. The non-carcinogenic risk of Mn was 1-4 orders of magnitude higher than that of other heavy metals, and HQ value for non-carcinogenic risk in children were higher than in adults. The HI value of heavy metals for non-carcinogenic risk were higher than the human acceptable limit value 1.0 in three kinds of particles through inhalation exposure, which was attributed to the contribution of Mn. The non-carcinogenic risk in the study area was serious. The CR value of adult cancer risk was greater than 10^-4 in terms of inhalation of Co in PM₁₀ and TSP, and Cr in TSP. However, CR values for most of the other heavy metals were within the acceptable range. In addition, CRT values for the adult carcinogenic risk of the three kinds of particles were higher than those of children. CRT value for the children carcinogenic risk of heavy metals in PM_2.5 was less than the upper acceptable limit for human body (10^-4), while all the other CRT values were higher than 10^-4, indicating that the carcinogenic risk was also serious.