Floating plastics in Adriatic waters (Mediterranean Sea): From the macro- to the micro-scale. (November 2018) - Zeri, C.
Abstract: Macro- and microplastics abundances were determined in the Adriatic Sea following the MSFD TG10 protocol. The studied areas included populated gulfs, river outlets and offshore waters in five Adriatic countries. The use of small ships enabled us to detect small sized plastics (2.5–5 cm) and record average macroplastics densities of 251 ± 601 items km −2, one order of magnitude higher than previously considered. Results from manta net tows for microplastics revealed an average abundance of 315, 009 ± 568, 578 items km −2 (217 ± 575 g km −2 ). We found significantly higher microplastics abundances in nearshore (≤4 km) than in offshore waters (>4 km) and this trend seems to affect also the small sized macro plastic fragments (2.5–5 cm). The dominant polymers were polyethylene and polypropylene while the presence of some rare polymers and waxes used in food and dentistry indicated waste water treatment plants as potential sources of microplastics. Highlights: Average macroplastics densities found one order of magnitude higher than previously considered. About 49% of macroplastic items had sizes in the range of 2.5–5 cm. Macroplastics compositional differences indicate the shape and type of polymer as controlling factors. Microplastics, mesoplastics and small-sized fragments were decreasing offshore. Polymers with sole uses in dentistry provide evidence that WWTPs are sources of microplastics.