Microplastic sampling in the Mediterranean Sea

The extent of microplastic pollution in the Southwestern Mediterranean Sea is not yet known, although on Northwestern part has been previously studied. Plastic samples were collected at 7 transects during a 10 day expedition from Sicily (Italy) to Malaga (Spain) in September 2014. A 330 µM mesh manta trawl was used for surface water sampling. Physical and chemical characterization of plastic particles was performed with regard to size (1-< 5 and >5mm), shape (fragment, line, thin film, foam and pellets), color (transparent, white, black and colored), density and chemical composition according to 5 Gyres protocol. Microplastics (< 5mm) were more abundant than macroplastics (>5mm) across all sites. Abundance decreased with increasing distance from the coast of Palermo to the open sea, with the highest abundance (20717 particles per Km2) observed at the Sicilian coast. Fragments were the dominant shape of plastics with 86% and 75% of < 5mm and >5mm sizes, respectively. Transparent plastics comprised the majority of total plastic particles obtained with 65% and 56% of < 5mm and >5mm sizes, respectively. Despite their small number, plastics of >5mm weighed more than particles < 1mm. This is the first study to assess plastic pollution levels in SW Mediterranean Sea.