Sources, Distribution and Ecological Risk Assessment of Polycyclic Aromatic Hydrocarbon in Sediment of Tigris River, Iraq

Sediment samples were collected from five sites at Tigris River from Baghdad to Wasit Governorates River from December 2021 to November 2022. Sixteen polycyclic aromatic hydrocarbons (PAHs) in these sediment samples were analyzed. The results show that the total PAH concentrations ranged from 957.37 to 1805.05 μg/kg dry weight (dw) with mean values of 1368.034 μg/kg. Furthermore, the high molecular weight compounds (four, five, and six rings) of PAH in the analyzed sediment samples suggest that combustion sources such as fuel, gasoline, and vehicle emissions are the primary sources of PAHs in the environment. The sediment quality guidelines (SQG) based on the effects range low (ERL) and the effects range median (ERM) and risk quotient (RQ) were used to evaluate the ecological risks of polycyclic aromatic hydrocarbons (PAHs). The results showed that the risks were low to moderate, with potential biological effects of PAHs. The result of the current research work indicated that ongoing monitoring of PAH levels in sediments is needed.