Assessment of Heavy Metal Contamination and Ecological Risk in Soils Developed on Different Rock Types in Southern Bundelkhand Region, Central India

This study assesses heavy metal (HM) concentrations and ecological risks in soils derived from granite (GrS), basalt (BtS), and amphibolite (AmS) rocks in southern Bundelkhand, central India. HM analysis reveals substantial variations, with Cr, Mn, Co, Ni, Zn, and Cd exhibiting higher concentrations in AmS, followed by BtS and GrS. Mn and Co content exceeds the Indian limit for soil (IS) and European Union (EU) guidelines for most samples. The geo-accumulation index shows high pollution levels of Cd in all soil types. Enrichment factor (EF) assessment reveals significant enrichment of Cd in GrS and BtS (mean 12.53, 6.91, respectively), and Cr, Ni, and Cd in AmS. The potential contamination index (Cp) and pollution load index (PLI) confirm Cd as the most significant contaminant in all soil types, with AmS exhibiting the highest pollution levels (29.31 and 650.68, respectively). The potential ecological risk (RI) assessment identifies Cd as the major contributor to ecological risk in all soil groups, with GrS and BtS displaying low to moderate risk, and AmS posing high to very high ecological risk. Our study highlights the influence of parent material on soil heavy metal concentrations, potentially leading to groundwater contamination and posing risks to human health.