UTTAR PRADESH JOURNAL OF ZOOLOGY

Heavy metal contamination has rapidly increased in recent decades, having a significant effect on the aquatic environment and the organisms inhabiting it. The principal objective of this study was to determine the concentrations of cadmium (Cd), chromium (Cr), lead (Pb) and mercury (Hg) in water, sediment and biological samples collected before and after the oil spill in Ennore Creek. The commercially consumed fish species Elops saurus and Gerres filamentosus were identified using morphometric characteristics according to an established protocol. Heavy metal concentrations showed marked variation among stations, with Pb exhibiting the highest levels in water and sediment

(320.31 μg/L and 856 mg/kg, respectively), followed by Cr (100 μg/L and 164.2 mg/kg). Among the biological matrices analysed after the oil spill, Elops saurus exhibited greater Cr accumulation (2.09 mg/kg), while polychaetes exhibited comparatively elevated Pb levels (1.60 mg/kg). Overall, the elevated metal concentrations, particularly in sediment and biota, indicate potential bioaccumulation and ecological concern in the study area. Pollution indices, including the geoaccumulation index, pollution load index and bioaccumulation factor, indicated increased pollution following the oil spill. These findings highlight the need to protect and improve aquatic ecosystem health for future generations.