Coastal waters off Nouakchott support fisheries and, more recently, offshore oil activity and iron-ore export, all of which raise the risk of marine contamination. Local biomonitoring tools are still lacking. We asked whether the wedge clam Donax rugosus , abundant on Nouakchott’s beaches, can serve as a sentinel. Acetylcholinesterase (AChE), an enzyme inhibited by organophosphate and carbamate pesticides and by several trace metals, was measured together with the physiological condition index (CI). Clams were collected monthly from September 2022 to July 2023 at two beaches, Nicola and Hôtel Sabah. AChE was first assayed in four organs (mantle, digestive gland, foot, gill) and then followed monthly in the gills. Activity differed strongly among organs: the mantle was highest (about 16.0 nmol min⁻¹ mg⁻¹ protein, two-site mean) and the gill lowest (about 2.6), roughly a six-fold range. We retained the gill for the time series because its low, stable baseline is easy to read. Gill AChE and CI both changed with season, each peaking in summer; gill AChE was lowest in autumn and rose with water temperature, while CI fell in spring, the period when Donax spawns. Paired tests showed no significant difference between the two beaches for either variable, and the AChE–CI link was weak overall. Gill AChE in D. rugosus is a workable, low-baseline biomarker for coastal biomonitoring in Mauritania, on the condition that temperature and reproductive state are accounted for when the data are interpreted.
Roughaya Hassen Sarr, Sidi Ahmed Elemin, Z. Sidoumou et al.· Journal of Ecological Engine...· 0 citations
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.
Khadijatou El Hassen, D. B. Sghaier, Mohamed Avoulwatt et al.· Frontiers in Environmental S...· 0 citations
