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Heavy metal pollution in aquatic sediments poses significant ecological and human health risks due to its persistence, toxicity, and bioaccumulation potential. This study aims to assess the concentrations, contamination status, ecological risk, and potential sources of Chromium (Cr), Lead (Pb), Copper (Cu), and Iron (Fe) in surface sediments from the industrial belt of Kochi, Kerala, India. Sediment samples were collected from selected sites and analyzed using Flame Atomic Absorption Spectroscopy, revealing elevated metal concentrations, with maximum values of 2.87 mg/kg (Pb), 68.74 mg/kg (Fe), 1.42 mg/kg (Cr), and 1.75 mg/kg (Cu). Pollution assessments using the Heavy Metal Pollution Index, Single-Factor Index, and Metal Pollution Index indicated severe contamination at all locations, with contamination factors for Pb, Fe, and Cu reflecting heavy pollution. Enrichment Factor analysis suggested significant anthropogenic input of Pb and moderate enrichment of Cr and Cu. Despite elevated concentrations, ecological and toxicological risk indices including the Ecological Risk Index (ERI), Overall Risk Index (ORI), Probable Effect Level (PEL), mean PEL quotient, and Toxic Risk Index (TRI) indicated low biological risk, as most metal concentrations remained below ecotoxicological threshold values. Strong positive correlations (r > 0.90) among indices confirmed spatial consistency in contamination patterns. Principal Component Analysis (PCA) explained 98.62% of the total variance, identifying Pb and Cu as dominant contributors. Positive Matrix Factorization (PMF) identified three primary sources: an Fe-rich industrial source, a geogenic/urban background, and a high-risk, multi-metal source dominated by Pb and Cr. The findings highlight the cumulative impact of industrial discharges and urban runoff on sediment quality and emphasize the need for targeted remediation and long-term monitoring in this vulnerable estuarine system.
Arsha et al. (Mon,) studied this question.