A statistical analysis-driven assessment of heavy metal risks in coastal sediments of the Gulf of Kutch, India: Integrating field data with meta-analysis.

This study presents a comprehensive assessment of heavy metal contamination in the coastal sediments of the Gulf of Kutch (GoK), India, using integrated statistical techniques and meta-analysis. Sediment samples were collected from eight intertidal locations (Jakhau, Kathda/Mandvi, Modhva, Luni, Kandla, Navlakhi, Rozi Port, and Sikka), representing a gradient of anthropogenic influence. A total of 72 sediment cores were analyzed using X-ray Fluorescence (XRF), and pollution was evaluated through indices including the Contamination Factor (CF), Enrichment Factor (EF), Geo-accumulation Index (Igeo), Pollution Load Index (PLI), and Modified Degree of Contamination (mCd). The results revealed the presence of 28 trace elements, with dominant concentrations in the order: Ca > Al > Fe > Na > K > Sr > Mn > Ba > Zr > V > Cr > Zn > Ni > Nd > Cu > Sm > Y > Ga > Th > Co > As > U > Ta > Hg > Se > Pb > Ag > Cd. Mercury (Hg) exhibited localized enrichment, particularly at industrial and port-influenced sites. Statistical analysis (ANOVA, M-estimation) revealed significant spatial variability in metal concentrations, whereas depth-wise analysis indicated limited vertical differentiation, likely due to bioturbation and hydrodynamic mixing. The Pollution Load Index was found to be 1.25 across most sites, indicating pollution load. Among the analyzed contaminants, mercury (Hg) was observed to have Igeo value between 3 and 5 with average mercury concentration of 0.79 ppm indicating matter of concern coinciding with the threshold limits. A meta-analysis of regional studies further contextualized the observed metal levels within broader environmental trends. These findings underscore the need for continued monitoring and mitigation of trace metal inputs to protect marine ecosystems and human health in this sensitive coastal zone.