Trace elements contamination and Potential ecological risk assessment of sediments from mangroves region, Muthupet, after Fengal Cyclone 2024, Tamil Nadu India

Mangrove wetlands serve dual roles, acting as both sources and reservoirs of various pollutants. This study assessed the current status of trace element contamination and textural characteristics of surface sediments from Muthupet mangrove region. A total of 25 surface sediment samples were collected, and their textural characteristics, potential ecological risk indices, and statistical analyses were applied to evaluate contamination levels. Sediment textural analysis revealed a predominance of mud (silt + clay) followed by sand, indicating a low- to moderate-energy environmental condition. The distribution of organic matter and calcium carbonate was influenced by mangrove vegetation and shell fragments. Trace element concentrations of Fe and Mn in the sediments likely originated from riverine inputs and geogenic processes. The overall order of trace element concentrations was: Fe > Mn > Pb > Zn > Cr > Ni > Co > Cu > Cd. Compared to the Upper Continental Crust (UCC), sediments were enriched in Pb, Zn, Cd, and Co and depleted in Fe, Mn, Cr, Cu, and Ni. Sediment quality guidelines, contamination factor, geoaccumulation index, enrichment factors, sediment pollution index, and pollution load index indicated sediment conditions ranging from uncontaminated to moderately contaminate. Potential ecological risk assessment suggested low to moderate risk levels. Statistical analyses indicated that both natural and anthropogenic sources influence heavy metal delivery in the mangrove environment. Co, Ni, and Pb was primarily associated with nearby industrial activities and their effluents, representing the main anthropogenic source. Cd, Co, and Zn were linked to cement columns used in oyster farming, as well as agricultural runoff and pig farming discharges, representing a secondary agricultural source. Multivariate statistical analyses further supported that anthropogenic inputs are the dominant contributors to heavy metal accumulation in this mangrove ecosystem.