Microplastic contamination in mauritanian marine ecosystems: evidence from fish and mussels

Microplastic pollution has emerged as a pervasive threat to marine ecosystems, yet data from the West African region, particularly the Mauritanian Exclusive Economic Zone (EEZ), remain scarce. This study investigated the occurrence and polymer composition of microplastics in marine organisms occupying different trophic levels along the northern, central, and southern zones of the Mauritanian EEZ. A total of 45 fish specimens representing five species and 225 bivalves belonging to Donax rugosus and Perna were collected during offshore sampling campaigns. Organic matter was digested using hydrogen peroxide and potassium hydroxide, followed by stereomicroscopic examination and polymer identification using Fourier-transform infrared spectroscopy (FTIR-ATR). Microplastics were detected in all investigated taxa, indicating widespread contamination across species and habitats. Filaments (fibers) were the dominant particle morphology, accounting for 60% of the detected particles, followed by fragments (25%) and other forms (15%). Black particles were the most common color category (45%), followed by transparent particles (25%). FTIR-ATR analysis identified eight polymer types, with polystyrene (PS) being the most abundant (25%), followed by ethylene vinyl acetate (EVA, 20.8%), acrylonitrile butadiene styrene (ABS, 16.7%), polyvinyl chloride (PVC, 12.5%), polyethylene terephthalate (PET, 8.3%), nitrile (8.3%), polypropylene (PP, 4.2%), and polycarbonate (PC, 4.2%). The occurrence of microplastics in commercially and ecologically important species highlights the need for systematic monitoring in the region. This study provides baseline data on microplastic contamination in Mauritanian marine biota and contributes to filling a critical knowledge gap in West African marine pollution research.