Heavy metals in dusts from commercial and residential areas of Jharia coal mining town

摘要

People living in coal mine and other coal-based industrial areas are prone to health risk from heavy-metal exposure in dust emissions. Establishing the source of the toxic metals in dusts is important for policies for minimizing their human exposure risks. Dust samples from commercial and residential areas of Jharia coal mining town (India) were collected and analysed for major and minor elements. Fe, Ca, and Al were the most abundant major elements in the dust samples. Although the absolute concentrations of heavy metal in the dust followed more or less a similar trend, the enrichment factors (compared to control) of heavy metals decreased in the order: commercial site (Rb ＞ Cr ＞ Pb ＞ Ni ＞ Zn ＞ Cu ＞ Co ＞ Sr) and residential site (Ni ＞ Cr ＞ Rb ＞ Co ＞ Sr ＞ As ＞ Cu ＞ V). Pollution load index, calculated based on the relative enrichment was higher for the residential site (1.534) than for the commercial site (1.366). Seasonal variations were significant for As, Co, Cr, Ni, Pb, and Sr. The concentration of all the elements was higher in winter season, except the Pb content was higher in summer. Enrichment factor, principal component, and cluster analyses suggest that Cu, Cr, Co, and Ni in dusts originate from coal, and Pb and Zn from vehicular and traffic-related emissions. For exposure risk assessment, the total chronic daily intake calculated for each element of interest was divided by the corresponding toxicity reference dose to yield hazard quotient. The hazard quotient values were ＜1.0, indicating no risks to people from these heavy metals; however, the physical dust may have human health effects. Further studies are needed on the direct health effect of dust particles.