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

Abstract

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 HQCr > HQAs > HQZn > HQPb > HQCu > HQHg, 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 CRAs > CRCr > CRPb, 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.