The Effects of Agricultural Wastes on Degradation of PAHs and Abundance of Ammonia-Oxidizing Bacteria and Archaea in Soils

Abstract

The effects of agricultural wastes on degradation of polycyclic aromatic hydrocarbons(PAHs) and abundance of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) in PAH-polluted soils were determined by liquid chromatography and real-time quantitative PCR. The results showed that addition of agricultural wastes didn't improve the degradation of PAHs, in the contrary, the degradation of PAHs decreased in the soil added with wheat straw. And the degradation rate of PAHs decreased with increased molecular weight of PAHs. Furthermore, the abundance of AOA and AOB was enhanced in PAH-polluted soils after adding agricultural wastes, the content of pyrene and benzo(a)pyrene has significant negative correlation with the abundance of AOA. These results suggested that the degradation of PAHs can not be promoted through applying agricultural wastes into the soils freshly polluted by PAHs. Pyrene and benzo(a)pyrene would reduce the abundance of AOA, while addition of agricultural wastes could improve the ammonia oxidation function in PAH-polluted soils. This study provided some insights for the remediation and risk assessment of PAH-polluted soils.