Spatial distribution and Assessment of heavy metal contamination in the surface soil ofKovalam Catchment Chennai, South India

This research study aims to investigate the spatial distribution of heavy metals (HMs) and the potential risks of soil contamination within the urban catchment of Chennai Metropolitan City, located in Tamil Nadu, India. A total of sixty-four samples were systematically gathered from various locations throughout the study area during the pre-monsoon and post-monsoon seasons. The sampling followed a grid-based pattern, and the precise locations were recorded using a Global Positioning System (GPS). Raster-based maps illustrating the spatial spread of heavy metals were produced using the Inverse Distance Weighted (IDW) interpolation methods. Utilizing a graphite furnace atomic absorption spectrometer (AAS), the levels of the heavy metals – specifically Fe, Mn, Pb, Cu, Co, Cr, Zn, Ni, and Cd – were quantified in the gathered soil samples. To evaluate the human-induced impact of potentially hazardous elements within the catchment area, several indices were computed, including the Enrichment Factor (EF), Contamination Factor (CF), Geo-accumulation Index (Igeo), and Pollution Load Index (PLI), along with statistical analysis using Pearson’s correlation. The findings indicate that, on average, most heavy metal concentrations were below the Upper Continental Crust (UCC) reference levels, except for copper (Cu), cobalt (Co), and cadmium (Cd), which exceeded those benchmarks. EF values ranged from moderate to significant enrichment, while CF results indicated high to very high levels of contamination. The Igeo values suggested conditions from uncontaminated to heavily pollute. PLI results revealed pollution levels ranging from low to high. Based on these outcomes, remediation and awareness strategies are advised to mitigate ecological degradation and safeguard public health.