Evaluation of trace elements concentration in surface sediments of Parishan International Wetland (Fars Province, SW Iran) by using geochemical and sedimentological analysis

Abstract

This study investigated the concentration of trace metals in surface sediments of Parishan Lake. Parishan Lake is one of the biggest freshwater lakes in the Middle East, situated in Kazerun area (Fars Province, Iran). This preliminary study concerns the mineralogy, enrichment level, and trace elements source identification in surface sediment of this lake. The geochemical Enrichment Factor (EF) and Geo-accumulation index (Igeo) and sedimentological approaches were applied to characterize the contamination by heavy metals, comparing with Average Shale. Multivariate statistical analysis was also used to identify probable studied elements sources in collected samples. The XRD and microscopic analysis show that main mineral of surface sediments is aragonite with small amounts quartz and nepheline. Chemical analysis of sediments showed that the mean concentrations of As, Cd, Cr, Cu, Ni, Pb, Zn, and Sr were 1.88, 27.2, 32.4, 18.6, 8.1, 38.4, and 3934.9 mg/kg, respectively, and average concentrations of Cd, Cu, and Sr exceeded the corresponding values of upper continental crust (UCC) values. The outcomes of this study indicate that geochemical indices (EF and Igeo) revealed an extremely high enrichment for Sr, whereas other elements had minimal enrichment. The levels of potential ecological risk index (RI) for studied trace elements in all sampling locations were 41.13 and 23.76, lower than baseline value (150), signifying that ecological risks displayed by those elements in sediments were moderate. The multivariate statistical analysis indicated that Sr had a geogenic source (natural source), while As and Cd came probably from Industrial source (chemical fertilizers), Ni and Cr were likely derived from vehicle emissions, particularly agricultural machinery, and Pb originated from exhaust and non-exhaust traffic emissions.