Urban contamination assessment of polycyclic aromatic hydrocarbons released from an oil refinery in Rawalpindi

Polycyclic aromatic hydrocarbons are among persistent organic pollutants and incomplete combustion of hydrocarbons during petroleum processing activities may cause polycyclic aromatic hydrocarbons contamination in the surrounding area. For the first time in Morgah, Rawalpindi, Pakistan, three targeted polycyclic aromatic hydrocarbons i.e. naphthalene, phenanthrene, and pyrene were estimated from surroundings of an oil refinery. Samples were collected simultaneously in soil, water, and leaves of Melia azedarach L., a widely grown tree species in the sampling area, along different selected sites of main drainage coming out of the refinery. Among three polycyclic aromatic hydrocarbons, pyrene was observed in maximum concentration (24.31 mg/kg in soil) among all selected environmental media and studied compounds showed a dynamic behavior in context of accumulation at different sampling points. There was a significant effect of distance, from petroleum refining area on polycyclic aromatic hydrocarbons levels in soil, water and plant leaves. Our findings provide conclusive evidence that location of an oil refinery has attributed to high polycyclic aromatic hydrocarbons contamination in selected study area which can pose significant risk to general environment and to the public.