Analysis of Polycyclic Aromatic Hydrocarbons in Smoked Fish Sold in Akure Markets, Ondo State

Polycyclic aromatic hydrocarbons are a class of chemical compounds formed during incomplete combustion, and their occurrence in smoked food products is a recognised carcinogenic risk. Traditional smoking methods widely used for fish preservation in South West Nigeria involve direct exposure to wood smoke, which potentially introduces high levels of polycyclic aromatic hydrocarbons into the food matrix. This study analysed polycyclic aromatic hydrocarbon concentrations in smoked fish samples sold in markets in Akure, Ondo State. Samples of three commonly smoked species, namely catfish, croaker, and tilapia, were purchased from five market stalls. Polycyclic aromatic hydrocarbons were extracted using saponification and liquid-liquid partitioning, followed by high-performance liquid chromatography with fluorescence detection. Fourteen US EPA priority polycyclic aromatic hydrocarbons were quantified. Total polycyclic aromatic hydrocarbon concentrations ranged from 18.4 to 143.6 micrograms per kilogram across samples. Benzo[a]pyrene, the regulatory marker compound, was detected in all samples at concentrations of 0.8 to 12.4 micrograms per kilogram, with five samples exceeding the EU maximum level of 2.0 micrograms per kilogram. Naphthalene, phenanthrene, and fluoranthene were consistently the most abundant compounds. Catfish showed the highest total polycyclic aromatic hydrocarbon levels, correlating with its higher fat content. These results highlight significant dietary exposure risks for regular consumers of traditionally smoked fish in Akure and recommend the adoption of improved smoking technologies that reduce direct smoke contact with fish surfaces.

Keywords: polycyclic aromatic hydrocarbons, smoked fish, benzo[a]pyrene, HPLC, Ondo State