Heavy metals and microplastics in the stomach contents of two fish species: Trachurus trachurus and Zeus faber along the North and Central Atlantic Coast of Morocco

Marine environments are increasingly affected by microplastics (MPs) and heavy metals (HMs) pollution, raising concerns about ecological and human health risks. This study investigates the presence (MPs) and (HMs) in the stomach contents of two commercial fish species, Trachurus trachurus and Zeus faber. This study aimed to assess the presence, quantify, and characterize MPs and HMs, as well as to evaluate the potential risks associated with microplastics and heavy metals. Samples were collected along the North and Central Moroccan Atlantic coast. MPs were identified using FT-IR spectroscopy, while HM concentrations were quantified through atomic absorption spectroscopy (AAS). Out of 122 specimens analysed, 46 % ingested MPs, with fibres being the most common form. Three polymer types were identified: polyamide, polystyrene, and acrylic. HMs analysis revealed the presence of mercury, cadmium, and zinc in 97 % of the samples, though concentrations remained below regulatory limits. The concentration hierarchy was Cd > Hg > Zn (mean in μg/kg dry weight: 3.24 > 2.75 > 2.73). The contamination risk from MPs was classified as "low" for all Z. faber samples and 95 % of T. trachurus, with 5 % in the "moderate" category. Regarding HMs, the Hazard Index (HI) was below 1 for adults but exceeded 1 in children consuming T. trachurus more than three times per week or Z. faber more than five times per week. No significant correlation was found between MPs and HMs contamination. Further research is needed to explore the interactions between MPs and HMs in commercial fish, as well as the influence of habitat type, diet, and ocean circulation.