Polycyclic aromatic hydrocarbons in ambient air at Agra: distribution and toxicity assessment

Abstract

Polycyclic Aromatic Hydrocarbons (PAHs) are a class of organic pollutants that are commonly found in the environment, largely due to combustion or processing of hydrocarbon fuels. PAHs are considered highly toxic for human beings and several of these compounds are carcinogenic, mutagenic and teratogenic. Human exposure to PAHs occurs principally by direct inhalation, ingestion or dermal contact as a result of the widespread presence and persistence of PAHs in the urban environment. With increasing awareness that PAHs are known and suspected carcinogens, this study was undertaken to monitor PAH compounds in Total Suspended Particulate Matter (TSPM) at the industrial site--Nunhai, Agra. For this purpose, TSPM samples were collected on glass fibre filter papers (EPM 2000) using High Volume Sampler (HVS 430) at Nunhai, Agra. 16 EPA priority PAH compounds were analyzed by a Gas Chromatograph equipped with FID detector. PAHs having high molecular weight, i.e., BghiP, BbF, DbA, BaA, BaP and IP, were the most abundant with concentrations ranging between 0.026 to 0.56 ng m(-3). The calculated mean TPAH value was 0.32 ng m(-3). The probably carcinogenic and possibly carcinogenic PAH as classified by International Agency for Research on Cancer (IARC) accounted for 42% and 38% respectively of the total PAH. The health risk associated with inhalatory exposure to PAHs was assessed on the basis of Benzo(a)pyrene concentration in air and Toxic Equivalency Factor (TEF) for individual PAH. In the present study, BaP concentrations ranged from 0.005 to 0.23 ng m(-3) with a mean value of 0.04 ng m(-3). Carcinogenic potencies for DbA and BaP in PAH mixtures based on TEF concept were 45% and 39% respectively. This underlines the importance of DbA and BaPas a surrogate compound of a PAH mixture in our environment in assessing human health risk.