COMPARISON THE BED SEDIMENT CONTAMINATION OF THE SOUTHERN PART OF EUPHRATES RIVER WITH SHATT AL-ARAB, IRAQ

Abstract

This study aims to investigate the contamination of Euphrates and Shatt al-Arab with heavy metals. Identifying the pollution degrees and the sources of contamination are among the aims of this study. The fieldwork was carried out in January 2018 by using Stream Sediments Core Sampler Device at depths ranges 20–58 cm from eight river bed sediment sites (from S1 to S12) along the course of Euphrates to Shatt Al-Arab (from north Hilla to Basrah). About twenty-five core samples were chosen for this purpose. Twenty-one of heavy elements were determined by XRF technique. These trace elements are; Ta, W, Ni, Mo, Cr, As, Br, Pb, Co, Ga, Zn, Sr, V, Zr, Mn, Ba, Th, Cu, Rb, Y and Nb. Four indices are selected to evaluate the contamination levels. These are; enrichment factor (EF), the geo-accumulation index (I-geo), contamination factor (CF), and pollution load index (PLI). According to EF mean values, the heavy metals W and Ta recorded a very high enrichment category denoting very high pollution, whilst Ni and Mo referred to a significant category. Nevertheless, the other metals reflected moderate to minimal category. I-geo mean values showed high polluted grade for Ta metal, and moderate polluted grade for Ni, Mo and W metals. However, the other metals were either unpolluted or moderate to unpolluted. Due to CF average values, the heavy elements Ni, Mo, Ta, and W reported very high contamination, but the other elements generally had moderate to low contaminated grade. It was clear that the very polluted heavy elements in the current study were Ta, W, Ni, and Mo. Moreover, the contaminated grade can be ordered as following; Diwania>Simawa>Nasiria>Hilla> Basrah. The high degree of contamination may be mainly attributed to different anthropogenic sources. The other reason maybe originated from the crustal materials of natural origin (lithogenic source).