新疆准东煤田降尘重金属污染及健康风险评价

为研究准东煤田大气降尘重金属的污染状况及潜在健康风险,选取52个覆盖全区的样点采集大气降尘,并测试分析样品中Zn、Cu、Cr、Pb、Hg和As共6种重金属元素含量.结合地累积指数(I_geo)进行污染研究,使用EPA人体暴露风险评价.结果表明,研究区大气降尘重金属浓度具有明显差异,Zn > Cr > Cu > As > Pb > Hg.Hg、Cu和As的变异系数为381.91%、99.94%和97.82%,受人类活动影响较大; 6种重金属间的相关性较复杂,Zn-Cu-Cr较Hg-As-Pb的相关性更强.地累积指数评价表明,重金属Zn、Cr的污染较严重,Zn处于极强度污染,Hg可视为无污染,Cu、Pb、As处于轻度-中度污染.研究区致癌风险暴露量与非致癌风险暴露量差异不大.非致癌风险商均小于1, HQ_Cr > HQ_As > HQ_Zn > HQ_Pb > HQ_Cu > HQ_Hg,总非致癌风险指数0.258,研究区6种重金属健康风险较小.致癌风险CR_As > CR_Cr > CR_Pb,Pb无致癌风险.其中As的致癌风险值占总致癌风险(TCR)的93.85%,是最主要的致癌因子.TCR均值为1.95E-05,处于人体可耐受的致癌风险范围.

Assessment of Heavy Metals Pollution and Its Health Risk of Atmospheric Dust Fall from East Part of Junggar Basin in Xinjiang

In order to evaluate the contamination and health risk of heavy metals from atmospheric dust fall in Zhundong opencast coalfield in Xinjiang, samples of atmospheric dust fall were collected from 52 sampling sites covering the entire region and the contents of Zn, Cu, Cr, Pb, Hg and As were tested and analyzed. The contamination was assessed by geo-accumulation index method, and the risk to human health was assessed using the US EPA Health Risk Assessment Model. The results showed that:The contamination of heavy metals from atmospheric dust fall had a significant difference, in the order of Zn > Cr > Cu > As > Pb > Hg, and the average contents were higher than the soil background of Changji. The coefficient of variation of Hg, Cu and As was 381.91%, 99.94% and 97.82%, and human activities had a greater impact on them. The correlation coefficients in 6 heavy metals were complex, the correlation coefficients among Zn-Cu-Cr were more relevant than Hg-As-Pb. The assessment results of geo-accumulation index indicated that the Zn pollution in the atmospheric dust fall should be classified as extreme degree, and that of Cu, Pb, As as between slight and extreme degrees, and Hg as practically uncontaminated. The exposure content of carcinogenic risk and non-carcinogenic risk of the study area had little difference. It was HQ_Cr > HQ_As > HQ_Zn > HQ_Pb > HQ_Cu > HQ_Hg, the total non-cancer hazard index was 0.258, the non-cancer hazard indexes were both lower than their threshold values, suggesting that they would not harm the health. The carcinogenic risk hazard indexes were in the order of CR_As > CR_Cr > CR_Pb, suggesting that Pb had no cancer risk, while As was the most important carcinogenic factor. The average TCR was 1.95E-05, indicating that the risk was within the limit that human can tolerate.