Polycyclic aromatic hydrocarbons (PAHs) concentrations and related carcinogenic potencies in soil at a semi-arid region of India

A study of polycyclic aromatic hydrocarbons in surface soil was conducted at selected locations in Agra (semi-arid region of India) for a span of one year in order to ascertain the contamination levels. The concentrations of PAH were measured at four locations in the city of Agra, which covers industrial, residential, roadside and agricultural areas. The samples were extracted with hexane by ultrasonic agitation. The extracts were then fractioned on a silica-gel column and the aromatic fraction was subjected to HPLC. The average concentration of total PAH in all samples was 12.1 microg g(-1) and the range was from 3.1 microg g(-1) to 28.5 microg g(-1). The maximum concentrations of PAHs were found to be in winter season. The concentration of PAH decreased in the order chrysene > benzo(b)fluoranthene > fluoranthene. Factor analysis suggests that the mixed signature of all the sources are intermediate between vehicular and combustion activities.