Levels of polycyclic aromatic hydrocarbons (pahs) in smoked and unsmoked fish from areas around lake Victoria in Mwanza and the effects of washing

This study investigated the types and concentrations of PAHs in three fish species from Lake Victoria in Mwanza Tanzania that were smoked and unsmoked samples. The study also investigated the effects of washing on the concentrations of PAHs in smoked fish. The PAHs in cleaned extracts were quantified using gas chromatography mass spectrometry (GC-MS).The PAHs detected were acenaphthylene, anthracene, chrysene, benzo[a]anthracene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, fluorene, phenanthrene, and pyrene. The concentrations of the total PAHs ranged from not detected to 0.3 µg/g, 12.08to 33.91 µg/g, and 0.08 to 44.43 µg/g in unsmoked, smokedand washed smoked fish, respectively. The mean concentrations of benzo[a]pyrene in smoked and washed smoked fish samples were 0.83 µg/g and 0.32 µg/g, respectively. The concentrations of benzo[a]pyrene in both smoked and washed smoked samples exceeded the permissible limit of 2.0 μg/kg (0.002)µg/g set by the European Commission which calls for concern. The levels of phenanthrene were significantly higher than of other PAHs; this might be due low smoking temperature.The concentrations and detection frequencies of the PAHs in the unsmoked fish samples were lower than in smoked and washed smoked fish samples. Washed smoked samples had lower levels and detection frequencies compared to the smoked samples indicating that washing reduces the levels of PAHs. However, no significant differences in the concentrations of PAHs were observed among the fish species. But there were significant differences among the categories of the samples and the mean concentrations of PAHs were in the order of smoked ˃ washed ˃ unsmoked.