Determining environmental factors affecting metal uptake in surface sediments

Heavy metal pollutants in water source sediments are a serious environmental concern in aquatic ecosystems. Sediments collect different amounts of metals and are both a source and a reservoir of heavy metals in aquatic ecosystems. In this study, four heavy metals, including nickel, lead, mercury, and cadmium, were collected and examined from the surface sediments of Bandar Imam (Ghanam Estuary, Zangi Estuary, Petrochemical Estuary, and Ahmadi Estuary). Increased industrial and petrochemical activities in Mahshahr and Imam Khomeini ports have led to an increase in pollutants, most of which enter the waters of the Persian Gulf. The amount of sediment contamination to metals was compared with international standards. Then, the amount of sediment contamination was compared between different estuaries in the region. Surface sediment sampling was performed using the Vane Veen grab method. All four heavy metals were identified in all sampling sites with concentrations higher than the standard value based on correlation analysis and principal component analysis. The results show that the concentration of some metals in sediments is higher than the limits set by the standards. Their mean concentrations decreased by Ni>Pb>Cb>Hg. Contamination in Khor Petrochemicals seems to be more serious, probably due to the contamination source's proximity to a point where there is a very high ecological risk and must be carefully surveyed and corrected. The data analysis showed that lead and cadmium originate mainly from human activities (industrial effluents). Due to their location, the waters of the Mahshahr and Khor Musa regions, which are the location of many petrochemical plants, are directly and indirectly exposed to organic and mineral pollutants. Organic matter and particle size are the main factors influencing the distribution of heavy metals in the sediment. More organic matter and smaller particle sizes result in settlement of heavy metals in the sediment.