Source apportionment and risk assessment of heavy metals in mangrove soils using multivariate and sensitivity analyses

Article Type

Research Article

Publication Title

Journal of Environmental Chemical Engineering

Abstract

Mangroves are salt-tolerant coastal vegetation that offer vital ecosystem services, including shoreline protection, carbon sequestration, and water purification for diverse species. Despite this, they are increasingly threatened by heavy metal (HM) contamination. This study presents one of the first comprehensive assessments of physicochemical properties and HM contamination in mangrove soils along India's East Coast, using advanced analytical techniques on 56 samples collected from four distinct sites. All four sites exhibited contamination by various HMs, with Ni, Pb, and Cr being the most prevalent. Their concentrations elevated in the order: Site 1 < Site 2 < Site 3 < Site 4. This pattern was again corroborated by the contamination index and geo-accumulation index across the HMs. Additionally, pollution index (Site 1: 0.97; Site 2: 1.72; Site 3: 2.33; Site 4: 2.85), and ecological risk index (Site 1: 36.32; Site 2: 68.25; Site 3: 92.67; Site 4: 116.39) also followed the same pattern. The self-organising maps (SOM) demonstrated similar neural patterns for Zn, Cd, Ni, Pb, and Cr, indicating common sources. Positive matrix factorization identified four distinct sources of HMs in the soil, indicating both natural and anthropogenic sources of pollution. Non-carcinogenic risk was not prominent in the area; however, carcinogenic risk was evident in children, especially through Ni and Cr across the sites. Sobol sensitivity analysis identified Cr and Ni concentrations as the most influential factors for carcinogenic risk. This study can serve as a roadmap for understanding soil characteristics in the coastal regions, thereby promoting informed actions in biodiversity management.

DOI

10.1016/j.jece.2025.118261

Publication Date

10-1-2025

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