Polycyclic Aromatic Hydrocarbons in Agricultural Soils of the Southern Subtropics, China

The contributions of persistent organic pollutants (POPs) from the subtropical regions of China to pollution of the global environment have been paid great attention; however, little is known about the state of POPs in agricultural ecosystems within these regions of China. This study primarily revealed the state of the contamination and distribution of polycyclic aromatic hydrocarbons (PAH) in agricultural soils in the subtropical regions. 115 surface soils (0–20 cm) were sampled in the breadbaskets of these regions. The concentrations and types of PAH were determined using gas chromatography linked to mass spectrometry (GC-MS). The total PAH concentrations ranged from 22.1 to 1 256.9 ng g−1, with a mean of 318.2 ± 148.2 ng g−1. In general terms, the current PAH concentrations were lower than most PAH levels reported in a number of investigations from different countries and regions. PAH isomer ratios indicated that pyrolytic origins, such as fossil fuel combustion related to vehicle tail gas and industrial emissions, were the dominant sources of PAH in the southern subtropical areas of China. Although PAH concentrations decreased with decreasing pollution, population, and traffic density, to a great extent PAH compositions were similar throughout subtropical soils, with naphthalene, phenanthrene, fluoranthene, and benzo(b)fluoranthene being dominant.