Identification of polycyclic aromatic hydrocarbons in soils in Taizhou, East China

Polycyclic aromatic hydrocarbons (PAHs) and their hazards in surface soil (n = 92) were investigated in Taizhou, China, which is an area in East China famous for production and exporting of rice. Total concentrations of PAHs in soils ranged from 2.3 × 10¹ to 7.6 × 10² with a mean of 1.8 × 10² μg/kg (dry mass; dm). Concentrations of 16 PAHs reported here were less than those observed in most previous studies in China and other countries. Concentrations of individual PAH in fluvo-aquic soils were greater than those in paddy soils except naphthalene. Fluoranthene and pyrene were dominant PAHs, which accounted for 19.7 and 13.3 % of the total mass of PAHs, respectively. Based on ratios of low molecular weight PAHs to high molecular weight PAHs, diagnostic ratios and principal component analysis, the predominant source of PAHs was combustion and pyrolysis, especially coal, natural gas, gasoline and diesel emissions from traffic, as well as burning of straw. Carcinogenic potencies of 13 samples were 1.1- to 2.9-fold greater than the target values promulgated by the Netherlands, indicating increased carcinogenic risks of soils from these sites. However, risks of cancer via accidental ingestion, dermal absorption and inhalation to humans posed by PAHs in soil were relatively small.