Analyzing and distribution of polychlorinated biphenyls (PCBs) in sediments along Shatt Al-Arab Estuary, Iraq

The object of this research is the polychlorinated biphenyls (PCBs) in sediments along Shatt Al-Arab estuary, Iraq. The study examines the problem of river PCB pollution. PCB effects on humans include cancer, impaired reproduction, neuro-developmental effects in infants, immunotoxicity and endocrine disruption. PCBs lead to liver damage and stimulate changes in the DNA sequence. The Shatt Al-Arab Estuary is formed in southern Iraq near Al-Qurna city after the confluence of the Tigris and Euphrates Rivers. The Shatt Al-Arab Estuary region is shared between Iraq and Iran. The Estuary receives pollutants when it is passing during Basrah City regions, due to industrial, agricultural and human activities which discharge the pollutants to the Estuary without treatment. The concentrations of Σ13 PCBs compound in sediment samples were determined and analyzed at each site by using gas chromatography-mass spectrometry (GC-MS, Agilent). Six sites were chosen along Shatt Al-Arab Estuary. They are Al-Qurna (S1), Al-Deer (S2), Al-Qarma (S3), Al-Ashar (S4), Abi Al-Khasib (S5) and Al-Fao (S6), at Basrah city, south of Iraq. Sediment samples were collected seasonally, starting from Autumn season on September 2019 to summer season on July 2020. The Σ13 (PCB-18, PCB-29, PCB-31, PCB-28, PCB-44, PCB-52, PCB-101, PCB-141, PCB-149, PCB-138, PCB-153, PCB-189, and PCB-194) concentrations at the sediment samples ranged from 4.48 ng/g in Al-Deer site during summer season to 27.75 ng/g in Al-Ashar site during winter season for all selected sites. The Al-Deer site were found to have the lowest mean of PCBs its 0.345 ng/g and Al-Ashar site were found to have the highest mean of PCBs its 2.135 ng/g. PCBs concentrations in sediment samples during autumn, winter, spring and summer seasons ranged from 7.75 to 21.68 ng/g, 16.25 to 27.75 ng/g, 7.28 to 22.01 ng/g and 4.48 to 14.41 ng/g, respectively. The congener distribution patterns in these samples indicate the dominance highly chlorinated congeners (tri- and hexa-PCBs) in comparison with remaining others PCBs congeners. This project is the first of its kind in Basrah and all Iraq that reports PCB concentrations in the region and is considered a baseline study and can be used for subsequent studies.