Bioaccumulation of Total Petroleum Hydrocarbon in Tympanotonos fuscatus and Crassostrea gasar from the Upper Reaches of the Bonny Estuary

This study assessed temporal variations of Total Petroleum Hydrocarbons (TPH) in water, sediment, Periwinkle (Tympanotonos fuscatus) and Oyster (Crassostrea gasar) from the Iwofe River, Niger Delta. Samples collected bimonthly from July 2018 to May 2019 were analyzed using gas chromatography. Sediment recorded consistently higher TPH concentrations than water, peaking in January (8.89 mg/kg), while water values remained low (0.01–0.02 mg/L). Oyster accumulated higher and more variable TPH levels (0.002–0.029 mg/kg) than Periwinkle (0.003–0.005 mg/kg), with significant temporal changes observed only in Oyster. Seasonal comparisons showed no significant difference for Oyster but a minor yet significant variation for Periwinkle. The overall pattern confirmed a clear accumulation hierarchy of sediment > Oyster > Periwinkle > water. These findings highlight sediments and Oysters as sensitive indicators of petroleum contamination and the importance of using multiple matrices to better understand hydrocarbon dynamics in polluted coastal ecosystems. The elevated sediment and Oyster concentrations underscore potential ecological risks and reinforce the need for continuous monitoring and improved management in oil-impacted environments such as the Niger Delta.