Spectroscopic characterization and accumulation of microplastics in the banquette of Posidonia oceanica in the Tunisian coasts

Plastic pollution is becoming an increasing danger to marine ecosystems with plastics accounting for 50–80% of marine litter. Seagrass beds, found in shallow coastal waters, play a crucial role in offering essential services and ecosystem benefits. In addition, Posidonia oceanica seagrass beds are regarded as highly effective environments for trapping contaminants. This research focused on examining the levels and movement of microplastics using P. oceanica banquettes, recognized for its effectiveness in capturing both organic and inorganic particles. The samples were collected from different beach sites (Bizerte, Tunisian Gulf, Hammamet, Mahdia, chebba, Kerkennah archapilego and Djerba), and the acid digestion of the banquettes of Posidonia was carried out followed by a qualitative analysis through 1H-NMR and FTIR. The obtained results revealed microplastics in all samples, and proven by two spectroscopy techniques FTIR and 1H-NMR. The abundant microplastics detected in 50% of the sites were Polysterene (PS), Polyethenetrephtalete (PET) and Polyvenylchloride (PVC), followed by propylene (PP), polyethylene (PE) and ethylene vinyl acetate (EVA), which were found in 37% of the sites. However, polyamides (PA) were found only in Bizerte site. In addition, the polymers found in this study are commonly employed in diverse pratical, such as packaging, textiles, and fishing gear, confirming that microplastic pollution is likely to vary with location at a relatively small scale.