Assessment of PAH pollution in mediterranean lakes and health implications for fish and consumers, case study: Manzala Lake, Egypt

This study aims to investigate the distribution, sources, and compositions of 16 polycyclic aromatic hydrocarbons (PAH) in Manzala Lake water and the organs of two fish species: M. cephalus and O. niloticus. In addition, it aims to assess associated health risks and examine protein pattern responses and histopathological lesions in fish from different lake sectors. ∑PAH, ∑COMB, and ∑CAR varied between (0.122–51.895), (0.1–49.63), and (0.08–19.949) μg/L, respectively. Many PAH compounds in the water exceeded the guidelines; benzo[a]pyrene in the muscles of O. niloticus exceeded the European Union (EU) guidelines (2 μg/kg), recording 14.18 and 4.59 μg/kg in the eastern and southern sectors, respectively. In general, the ∑PAH in the muscles of O. niloticus (799.79 ± 26.02 μg/kg) were higher than those of M. cephalus (213.75 ± 8.69 μg/kg) in the eastern sector, which indicates a high potential risk associated with the consumption of O. niloticus. The electrophoresis of protein patterns of the fish muscles recorded site- and species-specific alterations in the proteinogram. M. cephalus exhibited higher sensitivity to PAH but developed a greater tolerance to PAH contamination than O. niloticus. The histopathological investigation reported several lesions in both fish tissue samples, particularly from the southern sector. Fish from Manzala Lake can pose a carcinogenic risk to consumers, mainly O. niloticus, where the PAH4 carcinogenic index was above the EU guidelines (12 μg/kg) in O. niloticus from all sectors. The study highlights lake management's importance in preserving biodiversity and ensuring food safety.