Risk Assessment of Consumption of Pah-Contaminated Papyrocranus Afer from Banegbe River

Abstract

Aims: Polycyclic aromatic hydrocarbons (PAHs) are a group of organic compounds with two or more fused aromatic rings. They are present in the environment mainly as a result of incomplete combustion, such as in forest fires, internal combustion engines, wood stoves, and coal coking This study aims to determine the concentration of polycyclic aromatic hydrocarbons (PAHs) in river water and Papyrocranus afer samples from the Banegbe River. Study Design: To assess the potential health risks associated with PAH contaminants due to consumption of Papyrocranus afer fish from the Banegbe river, the concentrations of sixteen polycyclic aromatic hydrocarbons were measured. Place and Duration of Study: Fish samples were collected from different points of the Banegbe River Latitude 5o 14N and longitude 5o 22E, Latitude 5o 28N and longitude 5o 10E and Latitude 5o 43N and longitude 5o 14E. Methodology: Extraction and analysis of polycyclic aromatic hydrocarbon in fish and water samples were done. The analysis was carried out using gas chromatography/ Flame Ionization Detector (GC/FID). The human health risk impact resulting from consumption of contaminated fish from Banegbe river and Ekpan pond were estimated. Results: The bioassay results indicated that the middle-stream point of the Banegbe River water samples had the highest total PAHs concentration of 4.695mg/L when compared to downstream and upstream, with the value of 4.442mg/L and 1.340mg/L, respectively. Varying levels of PAH congeners were observed in the fish tissues, with fish samples from the middle-stream having the highest total concentration of PAHs during the dry and rainy seasons. PAH levels were higher during the dry season than during the rainy season. Mean hazard indexes were all below 1 (<1) for all the sampled points (below an acceptable cumulative threshold). Risk assessment conducted using benzo(a)pyrene carcinogenic and mutagenic toxicity equivalency factors (TEF and MEF) showed risk for middle-stream, down-stream, up-stream, and Ekpan pond, respectively. The cancer risk associated with the consumption of fish from the Banegbe River were all above the USEPA guideline (1.0× 10 -6) for potential cancer risk, 0.0328, 0.1648, 0.1096 and 0.5958 for TEF and 0.33128, 0.40564, 0.26809 and 0.02179 for MEF during the dry season for up-stream, middle-stream, down-stream and Ekpan respectively. During the rainy season the cancer risk associated with the consumption of fish were, 0.00222, 0.29698 and 0.01442 for TEF and 0.00329, 0.2179 and 0.2888 for up-stream, middle-stream and down-stream respectively. Conclusion: The study suggests that fish from the Banegbe River are not safe for human consumption.