Source apportionment and temporal trend of potentially toxic elements in a sub tropical coastal wetland

This study investigates the sources, levels, and temporal trends of potentially toxic elements (PTEs) in Nayband Bay, a subtropical coastal wetland in the Persian Gulf. A 50°cm sediment core was collected and divided into 25 subsections (2 cm intervals) for analysis. Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) was used to measure concentrations of PTEs, revealing the following average abundance order: Ca > Mg > Na > Sr > Fe > Al > K > P > Mn > Ba > Pb. Pollution indices (I_geo, CF, EF) and correlation analyses were applied to assess contamination levels and elemental relationships. Strong correlations were observed between Na and Sr, while the Geo accumulation index (I_geo) indicated Heavily to extremely polluted for Ca and Heavily polluted for Sr. Enrichment Factor (EF) analysis suggested that 79% of PTEs originated from anthropogenic sources, primarily linked to oil and gas industry activities, whereas 21% were of natural origin. Positive Matrix Factorization (PMF) modelling identified industrial development as the dominant pollution source, corroborated by EF results. Indeed, PMF model revealed that 56% of PTEs sources is belong to 1st factor throughout whole 475 years, which is defined as oil and gas industries. Sedimentation rate analysis traced pollution trends from 1980 to 2023, highlighting Sr and Na as the most significantly increasing contaminants, likely due to intensified transportation and oil field expansion. This study provides critical insights into anthropogenic impacts on coastal wetlands and underscores the need for targeted pollution mitigation strategies.