Plastic invasion tolling: First evaluation of microplastics in water and two crab species from the nature reserve lagoonary complex of Kune-Vain, Albania

Microplastic (MP) pollution is an emerging global challenge and actually has become a reality in aquatic ecosystems in Albania. According to the World Wildlife Fund (WWF) report of 2019, Albania, is one of the most problematic countries, with the highest percentage of untreated plastic waste, 73 %, and one of the top four countries with the highest norm of untreated plastic waste in the Mediterranean. This study evaluates and characterizes for the first time the MPs in water, sediment, and gastrointestinal tracts of two crab species, C. aestuarii and C. sapidus, common inhabitants of the lagoonary complex of Kune-Vain Nature Reserve, known for their important role in the lagoon ecosystem. The results showed that all sampled crabs had MPs in their gut in an average of 11.0 ± 1.85 items g, while the total MPs content in water ranges from 370 to 750 MPs per L. No significant difference in the content of MPs between the two crab species was found and a positive Pearson correlation, between microplastic abundance in the water and in the crabs regardless of species, was confirmed. The composition of microplastics showed consistency in crabs, sediment, and water, with fibers and pellets as the dominant types followed by microbeads, and fragments. Characterized MPs varied in size from <0.1 mm to 0.1-0.5 mm, showing variable colors of black, blue, and red domination. Fourier Transform Infrared Spectroscopy (FT-IR) analysis of the chemical composition of microplastics distinguished presence of the high-density polyethylene (HDPE), polypropylene (PP), polyethylene (PE), and low-density polyethylene (LDPE), which showed consistency in water, sediment, and crab samples. In conclusion, high levels of MPs pollution observed in the Kune-Vain complex represent a serious threat to the lagoon ecosystem and to the local inhabitants. Furthermore, studies on MPs' impact on biota and local population health are urgently required.