Distribution Pattern, Sources and Potential Risks of Polycyclic Aromatic Hydrocarbons in Urban Soils of Fuzhou City, China

Abstract

Polycyclic aromatic hydrocarbons (PAHs) were analyzed in 64 surface soil (0∼5 cm depth) samples collected from Fuzhou city, China. The sampling sites were randomly selected from various functional zones including parks, colleges and universities, residential areas, agricultural fields, industrial areas, and gas stations. Total PAHs (ΣPAHs) concentrations ranged from 14.0 to 5442.9 μg·kg−1 with a mean of 578.1 μg kg−1. The mean concentration of ΣPAHs in soil samples from different functional zones decreased in the order of gas stations (1140.9 μg·kg−1) > industrial areas (1131.6 μg·kg−1) > agricultural fields (514.3 μg·kg−1) > residential areas (393.3 μg·kg−1) > colleges and universities (245.8 μg·kg−1) > parks (222.0 g·kg-1). The calculated PAH isomer ratios indicated that pyrogenic origins such as motor vehicle exhaust, industrial activities and coal burning were the dominant sources. The total carcinogenic potency for each sampling site was calculated using toxicity equivalency factors (TEFs) to convert concentration of individual PAH to an equivalent concentration of benzo[a]pyrene (BaPeq). Comparing with the reference total carcinogenic potency calculated as a sum of Dutch target value for unpolluted soil with appropriate BaPeq, above 42% soil sampling sites in this study, especially for the sampling sites of gas stations, had certain potential ecological risks to human health.