Bioaccumulation of Polycyclic Aromatic Hydrocarbons in Fish from Oil-Impacted Creek Systems, Bayelsa State

This study investigated the bioaccumulation of polycyclic aromatic hydrocarbons (PAHs) in fish tissue from oil-impacted creek systems in Bayelsa State, South South Nigeria, and assessed the associated human health risk for consuming fish from these systems. The Niger Delta has experienced decades of petroleum contamination from pipeline leaks and operational discharges, with PAH accumulation in aquatic organisms representing a significant ecotoxicological concern. Fish samples of Chrysichthys nigrodigitatus, Tilapia zillii, and Mugil cephalus were collected from four oil-impacted and two reference creek stations. PAH concentrations in muscle tissue were determined by gas chromatography-mass spectrometry. Concurrently, sediment PAH concentrations were measured and bioaccumulation factors were calculated. Results showed that total PAH concentrations in fish muscle from impacted stations ranged from 412 to 1,840 nanograms per gram dry weight, significantly exceeding concentrations at reference stations. Naphthalene, phenanthrene, and fluoranthene were the dominant PAH compounds detected. Bioaccumulation factors were highest in Chrysichthys nigrodigitatus, a benthic species with greatest sediment contact. Human health risk assessment indicated that estimated daily intake of PAHs through fish consumption exceeded the permissible benzo(a)pyrene equivalent threshold in communities consuming fish daily from impacted creeks. Incremental lifetime cancer risk values exceeded the acceptable threshold of 10^-6 for regular fish consumers at all impacted stations. The study strongly recommends immediate public health advisories for affected communities, regulatory enforcement of petroleum discharge standards, and longitudinal biomonitoring of PAH accumulation in fisheries resources of the Niger Delta. Keywords: PAH bioaccumulation, oil pollution, fish tissue, cancer risk, Bayelsa State