Environmental assessment of PAHs in soils around the Anhui Coal District, China

Thirty-three soil samples were collected from the Luling, Liuer, and Zhangji coal mines, in the Huaibei and Huainan areas, Anhui Province, China, in 2007. The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs), identified as priority pollutants by the US Environmental Protection Agency (EPA), were determined by gas chromatography-mass spectrometry (GC-MS). The sum of 16 US EPA PAHs ranged from 0.13 to 3.54 microg/g (dry weight basis) with a mean concentration of 0.84 microg/g. Among the three sampling sites selected around the coal mines, the site at the Luling coal mine revealed maximum concentration of PAHs, whereas minimum concentration was observed at the site at the Zhangji coal mine. In general, low-molecular-weight PAHs were predominant. The gob pile and coal preparation plant are the sources of PAHs pollution in surface soils in the vicinity of coal mines. The crops in rice paddies might adsorb some PAHs and reduce the PAHs content in soils from paddy fields. The vertical distribution of PAHs in two soil profiles indicates that PAHs contamination in soil profiles tends to occur high in the surface soils and markedly decreases with soil depth. For all depths, PAHs showed a similar distribution pattern, which is an indicator of a similar origin. The total B[a]P equivalent concentration (B[a]Peq) was found to be maximum at the Luling area, whereas it was minimum at Liuer zones.