Effects of Phenanthrene on the key processes and functional genes of denitrification in sediments of Jiaozhou Bay

Abstract

Abstract Polycyclic Aromatic Hydrocarbons (PAHs) will combine with the particulate matter and settle in the sediments, which will influence the denitrification process. The study chooses the Dagu River estuary and the bay area of the northwest of the Jiaozhou Bay as sampling sites, and select Phenanthrene (Phe), the model compound of PAHs as a pollutant. The concentrations of Phe are 0mg/kg, 50mg/kg and 500mg/kg. The impact of Phe on nitrate reduction ability, nitrite reduction ability, related enzyme activity, and relative abundance of functional genes are explored. The results showed that in Jiaozhou Bay and Dagu River estuary Phe had a markedly effect on nitrate reduction, nitrite accumulation, nitrate reductase activity and nitrite reductase activity. The relative abundance of narG and nirS genes were markedly affected by Phe, and the inhibitory effect was enhanced with the increase of concentration. Compared with Jiaozhou Bay, the reduction of nitrate and nitrite in the Dagu River estuary are more sensitive to the pollution of Phe.