Content and source apportionment of polycyclic aromatic hydrocarbons in soil profile (0–100 Cm) of Urumqi petrochemical wastewater irrigation area, China

Abstract

ABSTRACT For studying the level of pollution by polycyclic aromatic hydrocarbons (PAHs) in the Xinjiang Urumqi petrochemical wastewater irrigation area of farmland soil profiles, 60 soil samples were collected from the wastewater irrigation area and 3 different land-use types (cultivated land, wasteland, and forest land) were included. To investigate the distributions of PAHs in soil, the source analysis is performed using the method of characteristic ratio and the total index method. The results show that the PAHs content in the surface soil of the sewage irrigation area is 237.3–2028.6 µg/kg, with an average value of 911 µg/kg. The PAHs contents in the soil of different land-use types are in the following order: woodland > cultivated land > wasteland. In the soil profile of the polluted irrigated area, 0–40 cm is the main polluted layer, the dominant component being the 2–3-ring PAHs. The monomer concentration and the total PAHs concentration both decrease with increasing soil depth. According to the characteristic ratio and the total index method, the irrigation of petrochemical wastewater is considered the main contributor to PAHs pollution in the soil of different land types in the sewage irrigation area. In addition, there is the problem of automobile exhaust emissions and the influence of incomplete combustion.