First evaluation of floating microplastics in the Northwestern Adriatic Sea

Plastic pollution in the marine environment is becoming a problem of global concern, and the Mediterranean is believed to be one of the worst affected regional seas. The present study presents data on floating microplastics in the Northwestern Adriatic Sea in order to evaluate the possible contribution of two significant potential sources: the lagoon of Venice and the Po River. Samples were collected in March and April 2014 along two transects located off Pellestrina Island (Venice) and the Po Delta, each consisting of four sampling stations at 0.5, 3, 10, and 20 km from the shoreline. Microplastics were quantified and classified according to their colors and shapes and analyzed by micro-attenuated total reflection-FT-IR. Microplastics were found in all samples, albeit with high spatial and temporal variability. The highest concentrations were observed in March at the offshore station of the Pellestrina transect (10.4 particles m^-2) and the two landward stations off the Po Delta (2.1 and 4.3 particles m^-2), highlighting the influence of various factors, such as surface circulation and river discharges, in determining specific accumulation patterns. The most common polymers were polyethylene and polypropylene, and most of the particles were secondary microplastics (83.5%). The patchy distribution of microplastics observed in the study area is driven by hydrodynamic and meteorological factors acting on short time scales.