Statistical Analysis and Geographic Distribution Mapping for Assessing Heavy Metal Content in Tigris River Sediments in Mosul City, Iraq – Post-War

Abstract

The armed conflict in Mosul has resulted in significant heavy metal contamination of sediments in the Tigris River, reflecting both direct impacts such as infrastructure destruction and indirect consequences including compromised waste management systems. During the monitoring period from 2022 to 2023, a total of 120 sediment samples were collected from ten sites spanning conflict-affected and surrounding areas along the river. Elevated levels of cadmium (Cd), lead (Pb), electrical conductivity, salinity, and total organic carbon (TOC) were particularly notable in the Old City of Mosul, a heavily impacted urban center. The highest contamination levels were recorded at Site S10, attributed to the unique hydrogeological conditions of the Tigris River. Contamination Factor (CF) analysis indicated severe pollution with Cd at all sites and moderate pollution with Pb, while zinc (Zn) concentrations remained within background levels. Chromium (Cr) and nickel (Ni) showed moderate to low contamination levels. Geo-accumulation Index (I_geo) values for Cd ranged from strongly to extremely polluted, whereas Pb ranged from low to moderate pollution. The Pollution Load Index (PLI) revealed spatial variation, with Zones 1 and 2 categorized as low pollution, Zone 3 as moderate pollution, and Zone 4, especially Site S10, as heavily polluted. Despite ongoing riverbank cleanup efforts, contamination levels remain elevated. These findings highlight Cd and Pb as priority pollutants posing significant ecological risks. The study recommends periodic sediment removal, phytoremediation, and chemical treatment, alongside strengthening waste management and sanitation infrastructure to mitigate further heavy metal infiltration into the river system.