Pollution Assessment of the Tigris River Sediments Resulting from Wastewater Discharge in Baghdad, Iraq

This study aimed to study the concentrations of some trace elements, such as Pb, Ni, Cd, Cu, Cr, Zn, Mn, and Fe and evaluate the level of pollution resulting from sewage on the Tigris River sediment by selecting eight stations distributed along the River (Central bank of Iraq, Jadriya Bridge, Al-Dora (Al-Dora silo), Sinak Bridge, Ahrar bridge, River street, Medical city, Al-Kadhimiya) in Baghdad City. The study was conducted during two seasons, winter and summer. Geochemical pollution indices such as geoaccumulation factor and contamination factor were used to evaluate the degree of acidity of river sediment. The results showed that the summer season of the Tigris River recorded relatively higher concentrations than the winter season. This may be because of the decrease in the dilution factor of these elements in the sediment due to the low water levels during the summer. According to the I-geo results, the sixth site's sediment is unpolluted with Fe, Mn, Cr, Ni, Zn, Pb, and Cd in both seasons and mildly polluted with Cu in the summer. The Cu contamination factor, classified as class 3, indicates significant contamination to severely pollute in summer, while Fe, Pb, Cu, and Zn conbankred unpolluted in both seasons. Fe, Mn, Cr, Ni, Pb, Cd, and Zn are not polluted in any season. However, Cu's contamination factor is classified as class 3, meaning significant contamination occurs during summer.