Accumulation and risk assessment of polycyclic aromatic hydrocarbons (PAHs) in soils around oil sludge in Zhongyuan oil field, China

In this paper, the contents of polycyclic aromatic hydrocarbons (PAHs) in soil samples around three different oily sludge plants in winter were analyzed by high performance liquid chromatography (HPLC) and the pollution degree with PAHs in soil samples was determined. Soil samples were collected from the agricultural soil around three different oily sludge plants (the Third Wenming Plant, the Third Mazhai Plant, and the Fourth Wener Plant) along with the leeway in Zhongyuan oil field. The distances from collected sample sites to oily sludge plants are 10, 20, 50, 100, 200, and 500 m, respectively. The results show that the contents of PAHs in soil samples decrease dramatically with the increase of the distance from the oily sludge, and that the PAHs with 2–4 rings are major pollutants in the oily sludge and soil samples. The main factors, which influenced the distribution of PAHs are discussed. Based on Nemero Index P, the classification evaluation shows that the soils around the oily sludge are heavily polluted in winter. The health risk assessment and ecological risk assessment of the soils around the oily sludge in Zhongyuan oil field in winter are analyzed.