Assessment Of Heavy Elements in Exchangeable Sediments from Al-Ezz River North of Basrah

Abstract

Seasonal sediment samples were collected from autumn (October 12, 2022) until summer (June 25, 2023) at five stations along the Al-Ezz River in the Qurna district, north of Basra city. The purpose was to assess the river's pollution with heavy metals: lead (Pb), cadmium (Cd), copper (Cu), manganese (Mn), zinc (Zn), chromium (Cr), cobalt (Co), and iron (Fe), using the sequential extraction phase. Additionally, pollution factors (CF), enrichment factors (EF), and the geochemical accumulation index (I-geo) were calculated to evaluate the degree of heavy metal contamination in the study area's sediments. The study results revealed that the annual average concentrations of the aforementioned heavy metals in the exchangeable phase were as follows (µg/g dry weight): lead (Pb) - 95.842, cadmium (Cd) - 8.549, copper (Cu) - 21.918, manganese (Mn) - 111.016, zinc (Zn) - 23.175, chromium (Cr) - 61.749, cobalt (Co) - 10.826, and iron (Fe) - 122.18. The pollution factor (CF) values indicated that the soil was highly contaminated with lead and cadmium, while copper, iron, and manganese showed low contamination. Chromium exhibited considerable contamination, while cobalt showed moderate contamination. According to the geochemical accumulation index (I-geo) values, the sediments of the Al-Ezz River were classified as heavily polluted with lead and extremely heavily polluted with cadmium. They ranged from not polluted to moderately polluted with copper, and were not polluted with manganese, zinc, and cobalt. The environment exhibited moderate pollution with chromium.