Sedimentological investigation of mining pollutants in watersheds using core sampling techniques: A case study of Tar Creek, Oklahoma, USA

This study investigates the vertical and spatial distribution of heavy metal pollutants in sediment cores collected from the Upper Tar Creek, an ecologically sensitive watershed impacted by lead-zinc mining in southeastern United States. Using stratified core sampling at three transect sites, the analysis focused on the concentrations of Pb, Zn, Cd, As, and Mn, alongside grain size distribution and organic matter content. Results revealed significant surface enrichment of Pb, Zn, Cd, and As, especially at the downstream site, suggesting recent anthropogenic deposition. In contrast, Mn showed increasing concentrations with depth, indicating geogenic input. Strong correlations were observed between metal concentrations, silt-dominated grain size fractions, and elevated loss-on-ignition (LOI) values, highlighting the role of fine, organic-rich sediments in metal retention. Pollution indices (Igeo, EF, CF, and PLI) confirmed substantial contamination, with Site C representing a critical depositional sink. The findings underscore the urgent need for sediment management strategies and contribute a replicable model for sedimentological assessment of mining-impacted river systems in tropical environments.