Environmental assessment of heavy metal concentration and pollution in the Persian Gulf

The main aim of the present study was to assess the pollution loading and ecological risk of toxicity levels in the surface sediment of the Persian Gulf. About 56 surface sediment samples were considered to determine the toxicity and the geochemical concentration of the heavy metals including 24 elements. The geochemical analysis revealed that among the measured elements, the highest mean concentration belongs to Mg (23,825 µg g –1 ) and the lowest value relates to Hg (0.017 µg g –1 ). The concentrations of the elements in the sediment showed that high enrichment of Fe and Al elements could be originated from anthropogenic sources. Based on the quantitative measurements of the geochemical indicators including geoaccumulation index (Igeo), potential ecological risk index (RI), and pollution load index (PLI), cobalt and cadmium were found to be in the high contamination and high-risk levels. Environmental modeling for overlaying of Igeo, RI, and PLI layouts, carried out in GIS to produce the spatial composite zoning of the study area, revealed the hotspots of composite contamination in the Khark, Kangan, and Hormuz regions affected by some oil and gas refining manufacturing, industrial zones and petrochemical units. Ultimately, the results of the statistical relationships confirmed the relatively strong and positive correlations between some major heavy metals (Al, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, V, and Zn) and clay fraction of sediments, Igeo and RI indicators.