Evaluation of metal contamination and ecological risk in surface sediments of an industrialized catchment: A case study of the Saz-Çayırova catchment, Northwestern Türkiye

Abstract

This study examined the spatio-temporal variations of metal pollution in the sediment of an industrialized watershed, aiming to identify ecological risks. In order to distinguish between anthropogenic and geogenic resources, six risk assessment indices were used: enrichment factor (EF), geo-accumulation index (I-geo), potential ecological risk (RI), contamination factor (CF), ecological risk assessment (ER), and Pollution Load Index (PLI). Surface sediment samples were collected during both dry and wet seasons from nine locations (seven monitoring sites and two reference sites) across the watershed. Reference concentrations used to calculate the indices were determined to accurately reflect the local characteristics of the watershed. The findings indicated that Cd, Pb, Zn, and Ni had high enrichment and contamination throughout the watershed. Specifically, all applied techniques revealed Cd as posing the highest ecological risk, which was attributed to industrial discharges. Notably, dry season contamination was found to be higher than the wet season. A comparison of the indices used revealed that PLI was more suited for spatial assessments, whereas RI analysis provided a better explanation for temporal variations. Consequently, this study provides valuable insights for developing measures against sediment contamination in industrial watersheds.