Geochemical Assessment of Heavy Metal Contamination in Topsoils of Al-Qarma, Western Baghdad, Using Geochemical Indices

Abstract

This paper highlights the urgent need for effective strategies to reduce pollution and provides insights into soil-quality management in urban, rural, and environmentally vulnerable areas in Iraq. It aims to investigate the heavy metals (Cr, Co, Ni, Cu, Zn, Cd, and Pb) in the topsoil profile using effective geochemical indices (Enrichment Factor, Contamination Factor, Pollution Load Index, and Geo Accumulation Index) in the Al-Qarma area, Western Baghdad. Twenty topsoil samples were collected and analyzed using X-ray fluorescence techniques. The average concentrations of Cr (255.5 ppm) and Cd (1.8 ppm) exceeded normal values, and the enrichment and pollution indices (EF, CF, PLI, and I_geo) indicated significant human impact, particularly in industrial, agricultural, and high-traffic areas. Pollution Load Index values exceeded one at several locations, reflecting soil quality degradation. The use of GIS utilities and geostatistical methods was useful for developing spatial distribution maps, identifying pollution hotspots and evaluating contamination levels against international and national guidelines. The results revealed that several sites exceeded international standards with high values in industrial and agricultural zones, high-traffic road networks, and garbage-dumping sites, reflecting significant anthropogenic influence. The spatial mapping presentation is helpful towards ecological monitoring and land-use planning