Biomonitoring of total petroleum hydrocarbons contamination in coastal sediments and accumulation in Tympanotonus fuscatus var. radula from Rivers State, Nigeria

Abstract

Abstract Petroleum hydrocarbon contamination in coastal environments poses significant ecological and human health concerns, yet bioaccumulation dynamics in benthic organisms remain underexplored in the Niger Delta. This study investigated the spatial and temporal variation of total petroleum hydrocarbons (TPHs) in sediments and Tympanotonus fuscatus var. radula ( Tf var. radula ) across three stations in Rivers State, Nigeria, using standard analytical protocols between January and June 2023. Sediment TPHs exhibited pronounced spatial heterogeneity, with Station 2 recording the highest mean concentration (3.076 ± 0.15 mg/kg) and Station 1 the lowest (2.786 ± 0.12 mg/kg). Temporally, sediment TPHs increased from January and peaked in March (3.40 ± 0.06 mg/kg) before declining towards June (3.10 ± 0.04 mg/kg). TPH concentrations in Tf var. radula showed a narrow spatial range (1.23 ± 0.07 to 1.25 ± 0.06 mg/kg), indicating consistent but measurable accumulation in this benthic species. Bioaccumulation factor analysis revealed strong enrichment of selected compounds, notably benzene (up to 130), n-pentadecane (up to 480), and n-hexadecane (up to 520), reflecting selective uptake of individual hydrocarbon fractions. Although sediment TPH concentrations were below the EGASPIN intervention limit, the persistence of petroleum hydrocarbons and their bioaccumulation in an edible mollusc highlight the need for continuous monitoring and strengthened pollution control to safeguard sediment quality, seafood safety, and ecosystem health in coastal waters of Rivers State, Nigeria.