Characterization of particulate matter and its related metal toxicity in an urban location in South West India

This study reports the quantification of the toxicity of particulate matter (PM)-bound metals and their possible associated risks to human health. For assessment of PM, 24-h samples of PM₁₀ and PM_2.5 were collected by Mini Vol-TAS sampler at an urban site of Pune. Samples were sequentially extracted with ultrapure water and concentrated HNO₃ and analyzed for “soluble” and “total” metals. Factor analysis identified the resuspension of road dust due to traffic, biomass burning, construction activities, and wind-blown dust as possible sources that played an important role for overall pollution throughout the year. Water-soluble proportion was found to be ≤20 % for Cr, Co, Fe, and Al; ≥50 % for Sr, Cd, Ca, and Zn; and a substantial proportion (～25–45 %) for Mn, Ba, K, Na, Ni, Mg, Cu, and Pb metals in PM₁₀. For PM_2.5, the water-soluble proportion was ≤20 % for Fe, Co, Ni, Cr, and Al, while Sr, K, and Cd were mostly soluble (>50 %) and Cu, Ba, Mn, Ca, Zn, Pb, Na, and Mg were substantially soluble (～25–45 %). In the present study, among the toxic metals, Cd and Pb show higher concentration in the soluble fraction and thus represent the higher bioavailability index and especially are harmful to the environment and exposed person. Risk calculations with a simple exposure assessment method showed that the cancer risks of the bioavailable fractions of Cr, Cd and Ni were greater than the standard goal.