Assessment of Trace and Heavy Metal Contamination in Soil: Distribution Patterns, Pollution Indices, and Environmental Risk Evaluation

Abstract

Soil contamination by trace and heavy metals is an important environmental concern because of their persistence, accumulation, and potential ecological effects. This study assessed the concentration patterns and contamination status of trace and heavy metals using a publicly available Heavy Metal Study dataset obtained from Mendeley Data, comprising 44 soil samples collected from a granitic terrain in South India. The dataset included concentrations of 14 elements: As, Ba, Co, Cr, Cu, Mo, Ni, Pb, Rb, Sr, V, Y, Zn, and Zr. Descriptive statistics, Contamination Factor (CF), Geo-accumulation Index (Igeo), Pollution Load Index (PLI), and Pearson correlation analysis were applied. Considerable variability was observed among the elements, with Cr, Zr, Co, Zn, and Y showing the highest coefficients of variation. Zr recorded the highest mean CF and was classified as having very high contamination, while Pb, Mo, Y, and Ba showed moderate contamination. Most other elements generally exhibited low contamination levels. The Igeo results indicated predominantly uncontaminated to moderately contaminated conditions, although localized enrichment was observed in selected samples. Sample S3 emerged as the principal contamination hotspot and was the only sample with a PLI above 1. Strong positive correlations were observed among Co, Cr, Cu, and Ni, while Y and Zr showed an exceptionally strong association. Overall, the findings indicate limited regional contamination with distinct localized anomalies requiring continued environmental monitoring.