Evaluation of polycyclic aromatic hydrocarbons (PAHs) contents of fishes, waters and sediments of Rivers Niger: human health risk assessment

Abstract

This study aimed to assess the levels of polycyclic Aromatic Hydrocarbon (PAHs) in fish, water and sediments samples collected from the confluence of the Niger Rivers in Lokoja, Kogi State.  Random sampling technique was used to collect samples from twenty locations; resulting in five composite samples labeled A, B, C, D, and E. Fish samples A (Catfish) and B (Tilapias) were bought from fishermen along the riverbank. The samples were extracted using a liquidliquid extraction (LLE) and solid-phase extraction (SPE) clean-up. Gas chromatography-mass spectrometry (GC-MS) was used for the determination of the sixteen priority PAHs. Only six out of the sixteen priority PAHs were identified. The PAH concentrations in water from various location ranged as
follows: BaP (0.083 to 0.113), Nap (ND-0.543), Ant (ND-0.083), BbF (0.0800.093), BkF (0.083-0.093) & Ph (ND-0.083) mg/L. Sediment concentrations across locations were as follows: Ant (ND-0.053), Nap (ND-2.210), Ph (ND0.053), BaP (ND-0.053), BkF (0.053-0.110) & BbF (0.053-0.383) mg/kg. Average PAH concentrations in Catfish & Tilapia were as follows: BaP (0.050
& ND), Ph (0.050 & 0.057), Ant (0.057 & 0.057), BbF (0.043 & ND), BkF (0.043 & ND) & Nap (2.383 & 1.947). Hazard Quotient (HQ), & pollution index (PI) were used to evaluate the human risk from consuming water and fish. The findings indicated that water, fish & sediments contained high levels of PAH
pollutants, with some measurements surpassing the permissible limits set by WHO. Strict pollution control measures are advised to adhere to, so as to protect both aquatic ecosystems and human health.