Carcinogenic and non-carcinogenic risks from PM₁₀-and PM_2.5-Bound metals in a critically polluted coal mining area

This study analyzed the carcinogenic and non-carcinogenic risks of PM₁₀-and PM_2.5-bound trace metals, using exposure pathways, in a critically polluted coal mining area, the Jharia coalfield (JCF), India. The human health risks were calculated via ingestion (ing), inhalation (inh), and dermal (derm) absorption in adults and children. The cancer risks (CR) were evaluated as Total CR, CRinh, CRing, and CRderm, and the non-cancer risks as the hazard quotient (HQ) and hazard index (HI). The obtained CR levels were verified using the incremental lifetime cancer risk for inhalation exposure and Monte Carlo simulations for all exposure pathways. The HQinh and HI were found to be significant (>1) for both PM₁₀ and PM_2.5 at all 18 monitoring stations that were selected for this study. The Total CR for PM₁₀ was estimated to be maximum in the city near the mine-fire area (3.67 × 10⁻²), followed by the mine-fire area (2.26 × 10⁻²), while that for PM_2.5 was highest at the core mining area (1.06 × 10⁻²), followed by the city adjacent to the mine-fire area (8.85 × 10⁻³). The Total CR and CR for all individual exposures were not only found to be significant (>10⁻⁶), but also exceeded the acceptable CR levels (1.00 × 10⁻⁶- 1.00 × 10⁻⁴). Consequently, the study area fell in the high (10⁻³≤ to <10⁻¹) and moderate (10⁻⁴≤ to <10⁻³) risk categories for PM₁₀ and PM_2.5, respectively. Finally, Cd, Cr(VI), and Pb, which are signature elements of coal and oil combustions, were identified as significant contributors to the CR levels in JCF.