Distribution Pattern and Contamination Levels of Some Polycyclic Aromatic Hydrocarbons Along Roadside Soil at Major Traffic Intercepts During Autumn in Jalandhar, India

Abstract

Autumn season study of some automobile generated polycyclic aromatic hydrocarbons (PAHs) along roadside soil was conducted at selected city locations in Jalandhar (Punjab), India to ascertain the contamination levels and their distribution behaviour in soil. The concentration and type of PAHs were determined at ten locations at 1, 2 and 3 m distances along roadside soil covering all major traffic intercepts within city. Samples were extracted in acetone and dichloromethane (1:1) using soxhlet extraction. The extracts were filtered on a micro silica gel column to remove impurities and the eluates obtained were injected to GC-FID. The city average concentration of PAHs was found to be 16.38 μg g^-1 whereas, concentration of sixteen individual PAHs was found to vary between 0.01-252.55 μg g^-1. Average concentration of non-carcinogenic and carcinogenic PAHs was found 4.86 and 31.39 μg g^-1 (ratio 1:6.45), respectively. Five ringed PAHs were found in highest concentration (around 40-70 %) whereas, two ringed PAHs were in minimum concentration (around 0.28-0.56 %) at most of the intercepts. Average highest concentration for any individual location was found 46.54 μg g^-1 at location J4 at 1 m distance and minimum concentration was 0.77 μg g^-1 at location J9 at 3 m distance from roadside. Benzo(a)pyrene was the individual PAHs observed in highest concentration at all intercepts vary between 1.77-252.55 μg g^-1. At most of the intercepts within city, total carcinogenic PAHs concentration was quite high (85 %) in comparison to non-carcinogenic PAHs (15 %). Comparison of the city average of PAHs with Indian metro cities and world data indicate that their concentration is equal or even higher.