Distribution, Variations, Fate and Sources of Polycyclic Aromatic Hydrocarbons and Carbon in Particulate Matter, Road Dust, and Sediments in Central India
Pollution associated with polycyclic aromatic hydrocarbons (PAHs) and carbon emissions, resulting from fossil fuel combustion, is a matter of major concern in India. In this work, the distribution, variations, sources and fate of twelve PAHs (phenanthrene, anthracene, fluoranthene, pyrene, benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenz[a,h]anthracene, benzo[ghi]perylene and indeno[1,2,3-cd]pyrene) and carbonaceous particulate matter (elemental/black carbon (EC/BC), organic carbon (OC) and inorganic/carbonate carbon (CC)) in the air, road dust and sediments of three cities in the most industrialized area of Central India (Chhattisgarh state) are reported. The PM and road dust/sediment samples were collected by using a low volume air sampler and a stainless–steel scoop, respectively. PAHs were extracted into organic solvents and the dried residue was dissolved into acetonitrile for analysis. Carbons and PAHs were analyzed by thermal and chromatographic methods. Concentrations of particulate matter (PM10), total carbon (TC = EC + OC + CC) and total polycyclic aromatic hydrocarbons (∑12PAHs) of 116–523 µg m−3, 22.1–179.6 µg m−3 and 37.7–164.9 ng m−3, respectively, were found in air at the beginning of the study (2007/08). Concentrations of 6.02 − 9.87% (TC) and 8689 − 87458 ng g−1 (Σ12PAHs) were detected in road dust, while relatively lower concentrations were observed in sediments, in the 4.99–10.78% and 4721–11768 ng g−1 range, respectively. Regarding monthly and seasonal variations, the highest PAHs and TC concentrations occurred in December/January and in the winter season. Spatial (residential, commercial, and industrial areas) and temporal (2008-2015) variations of these pollutants are also discussed, together with their source apportionment based on factor analysis. Given that benzo[a]pyrene and ∑12PAHs concentrations clearly exceed the permissible limits, and that the concentration of PAHs in dust for one of the three cities under study (Bhilai) is the highest reported in the literature, this study shows the urgent need for continuous monitoring of organic aerosol constituents in the ambient air of the cities in this region.
