Heavy Metals and PAHs in Mollusks from The Sangomar Marine Protected Area in Senegal: A Baseline Study

This study provides the first baseline evaluation of heavy metals (Pb, Cd, Hg) and polycyclic ‎aromatic hydrocarbons (PAHs) in the bivalves Senilia senilis and Crassostrea gasar from the ‎Sangomar Marine Protected Area (Senegal), prior to offshore oil exploitation. Sampling was ‎conducted during the dry and rainy seasons of 2023-2024. Plomb and Hg concentrations ‎remained well below international safety limits, whereas Cd frequently exceeded the ‎permissible threshold, reaching 2.36 mg/kg dry weight in S. senilis. PAH contamination, ‎dominated by pyrogenic four-ring compounds (fluoranthene, pyrene), peaked in S. senilis ‎during the rainy season (190 µg/kg). Health risk assessment indicated that target hazard ‎quotients for Cd approached the critical value of 1 in S. senilis, suggesting possible long-term ‎risks to consumers. These results reveal high Cd exposure and seasonal PAH inputs likely ‎linked to runoff, providing essential reference data for environmental monitoring and ‎informing adaptive management strategies in the face of industrial expansion‎.