Polycyclic Aromatic Hydrocarbons (PAHs) in the Surface Sediments of Shatt Al-Arab River, Basrah City, Southern Iraq

Sediment samples collected from nine sampling sites along the Shatt Al-Arab River, Basrah City, Iraq were analyzed by gas chromatography-flame ionization detector in order to determine the degree and sources of PAHs contamination. The total organic carbon (TOC) content and grain size of sediments were also analyzed. The Shatt Al-Arab River sediments content of PAHs were relatively moderate compared to other  world-wide locations contaminated by oil. The total concentrations of PAHs ranged from 30.86 ng/g dry weight in the IX site to 87.79 ng/g dry weight in the VI site with highest content of PAHs were found in the Shatt Al-Arab River sediments near potential oil pollution sources, close to sites II, IV, VI, and VIII. The % TOC was varied from 0.32 to 1.64 %. The concentrations of PAHs in the Shatt Al-Arab River sediments appeared to be related to % TOC or grain size. The selected marked PAHs, the PAHs compounds ratios and the principal component analysis (PCA) suggest that the PAHs have originated from at least three different sources: (1) Pyrolytic-from different combustion processes, (2) petrogenic-from inputs petroleum and petroleum products, and (3) biogenic-from situ organisms. The potential ecosystem risk assessment indicated that PAHs will not cause immediate adverse biological effects in the Shatt Al-Arab River. Keywords: PAH compounds, Sediments, Shatt Al-Arab River, TOC, Basrah.