Determination of Polycyclic Aromatic Hydrocarbons (PAHs) in Clarias gariepinus and Tilapia zillii Smoked using Charcoal and Gas Smoking Kilns in Benue State

Abstract

Background and Objective: Fish is highly perishable of all staple commodities. Its perishability nature has necessitated fish preservation. Preservation of fish by smoking has been the major source of fish preservation in Nigeria. However, smoke is known to contaminate fish with polycyclic aromatic hydrocarbons, which are traced to carcinogenicity and mutagenicity. Preservation by smoking carried out by fish marketers in uncontrolled environments using firewood pulse a risk to consumers. Therefore, this study aimed to determine Polycyclic Aromatic Hydrocarbons (PAHs) in Clarias gariepinus and Tilapia zillii smoked using charcoal and gas smoking kilns in Benue State was carried out. Materials and Methods: Ten kilograms each of fresh Clarias gariepinus and Tilapia zillii were purchased from Wadata fish market landing site. Five kilograms of each fish sample were smoked using charcoal and gas-smoking kilns. The fish samples were then analyzed for Polycyclic Aromatic Hydrocarbons (PAHs) using gas chromatography coupled to a Hewlett packard 5972 mass selective detector. Results: The PAHs identified were of high molecular weight except for acenaphthalene, acenapthene and naphthalene, which were low molecular weight compounds. Tilapia zillii smoked using a charcoal smoking kiln showed low concentrations of PAHs and were undetectable in a gas smoking kiln. Clarias gariepinus recorded high concentrations of PAHs in both gas and charcoal smoking kilns, though all values were within safe limits as recommended by European Union (EU). Conclusion: Smoking of fish using a gas kiln resulted in lower levels of PAHs compared to the charcoal kiln. However, the PAH levels in both kilns were within the recommended limits as others were undetected. Therefore, the use of gas and charcoal as fuel sources for smoking fish is recommended as an alternative to the traditional method of firewood.