Contamination and environmental risk assessment of potentially toxic elements in the surface sediments of Northwest Persian Gulf

Abstract

To assess the contamination sources, patterns, and environmental risk related to potentially toxic elements (PTEs) in the sediment of the region, ninety-seven surface sediment samples were systematically collected from the marine boundary of the Iranian coastal territory in the northwestern Persian Gulf. The concentrations of major and trace elements in the sediments can be ranked as follows: Ca > Al > Fe > Sr > Mn > Ba > Cr > Ni > V > Zn > Cu > Pb > As > Mo > Cd.The study found that Ca, As, Sr, and Cd showed significant enrichment, while Ni and Cr showed moderate enrichment. The ecological risk index analysis indicated a low risk level, with Cd contributing to 61% and As contributing to 26% of the estimated risk. Anthropogenic sources were found to be responsible for significant enrichment of As and Cd in the northwestern Persian Gulf, particularly near coastal areas and in the Musa estuary. High concentrations of Arsenic result from urban/agricultural wastewater, industrial activities, and gas/oil fields. Natural weathering, riverbank erosion, and aeolian inputs also contribute to Arsenic levels. Cadmium pollution comes from wastewater, shipping, oil tankers, agriculture runoff, and industrial factories. Nickel and Chromium were moderately enriched, mainly due to their natural occurrence in high concentrations in the soil of southern Iran. The study also revealed a significant correlation among the elements Al, Ni, Cr, Fe, Mn, V, Zn, and Cu, suggesting that these elements predominantly originate from lithogenous sources. The study highlights the importance of identifying and controlling sources of As, Cd, Ni, and Cr pollution in the northwestern Persian Gulf to protect the marine ecosystem and public health. The implementation and enforcement of stricter environmental regulations can reduce PTEs contamination in the region and safeguard the aquatic ecosystem and public health.