Characterization and distribution of microplastics on the beaches of Southern Tunisia: a case study of the Island of Djerba

Microplastics (MPs), resulting from the degradation of plastic waste, were investigated on eight beaches on the Island of Djerba, located in the Gulf of Gabes in Tunisia. The study included 96 sediment samples collected in the summer of 2021 from four beach zones (dune, upper beach, coastline, and lower tidal line). The MPs were obtained using the NaCl density separation method and quantified through microscopic observation. MPs were classified based on shape, size, and dominant color. In addition, Fourier Transform Infrared Spectroscopy in attenuated total reflectance mode (FTIR-ATR) was used to identify the polymer composition of representative MPs. The results revealed microplastic concentrations ranging from 23 particles/kg at Gallela Beach to 126.67 particles/kg at Yati 2 Beach, with the highest accumulation found in the dune zone (65%) compared to the other zones. The samples were dominated by fragmented and fibrous MPs, with blue, red, and black being the most abundant colors. Polymer analysis revealed that polyethylene (PE) was the most abundant polymer, followed by polypropylene (PP) and polystyrene (PS). This study highlights significant spatial variability in the distribution of the microplastic on Djerba beaches, influenced by tourism, fishing, and urban runoff. These findings underline the urgent need for sustainable waste management to reduce microplastic pollution of the Island of Djerba and in Zarzis.