Distribution and health risks assessment of polychlorinated biphenyls in the muscles of <i>Oreochromis niloticus</i>, <i>Cyprinus carpio</i>, and <i>Sander lucioperca</i>, in Al-Massira Dam Lake (Morocco)

This study investigates the contamination levels of non-dioxin-like polychlorinated biphenyls (PCBs) in three fish species (Oreochromis niloticus, Cyprinus carpio, and Sander lucioperca) from Al-Massira Dam, Morocco.The sources of PCBs contamination include industrial activities and sewage treatment plants located in the watershed of the Oum Rbiaa river, and lubricating oils from electric transformers rich in pyralene from nearby industries and towns.Fish samples collected between July 2022 and June 2023 were analyzed using gas chromatography-mass spectrometry to determine PCB concentrations.Results show varying PCB levels across species, with Sander lucioperca (5.084 0.501) exhibiting the highest concentrations, followed by Cyprinus carpio (3.329 0.323) and Oreochromis niloticus (2.167 0.201).Predominant congeners include PCB28, PCB52, PCB101, and PCB180, reflecting species-specific accumulation patterns influenced by metabolic rates and dietary habits.Health risk assessments indicate that while PCB levels generally comply with safety guidelines for fish consumption, lifetime cancer risk (LCR) values exceed acceptable thresholds, particularly for adult and heavy fish consumers.Children, more vulnerable due to higher exposure and dietary habits, also face elevated risks.Non-carcinogenic hazard quotients (HQs) suggest high health risks for local fish consumers, emphasizing the need for ongoing monitoring and dietary management to mitigate PCB exposure.Although fish from Al-Massira Dam generally contain PCB levels below regulatory limits, their bioaccumulative nature underscores the importance of continued environmental monitoring and dietary management to protect public health.