POLYNUCLEAR AROMATIC HYDROCARBON CONCENTRATIONS IN ROAD DUST AND SOILSAMPLES COLLECTED IN THE UNITED-KINGDOM AND PAKISTAN

Concentrations of polycyclic aromatic hydrocarbon (PAH) were measured in samples of soils, surface and road dusts and air from various locat ions in Birmingham (UK) and Lahore (Pakistan). Urban surface and road dusts were observed to decrease in PAH concentration with increasing d istance from major roadways. PAH concentrations in soils in Birmingham were found to be comparable with other urban areas throughout the UK. A high correlation was found between airborne particulate matter and soil concentrations in Birmingham, which suggests that atmospheric dep osition is the dominant source of PAHs in soils. A high correlation wa s also found between PAH concentrations in soil and road tunnel dust; this illustrates the impact of vehicle emissions as the major source o f PAHs in urban areas. The high correlation between PAH species profil es distributed through soils in the UK provides evidence for either lo ng range dispersion and deposition of particles, or similar local emis sion sources in all sampled areas. PAH levels in soils from Lahore wer e considerably lower than those collected in Birmingham despite far hi gher atmospheric concentrations. This is most likely to be due to Paki stan's climate enhancing the effects of photo-oxidation and volatilisa tion. A high correlation was found between PAHs in airborne particles and soils in Lahore.