From the coast to the shelf: Microplastics in Rías Baixas and Miño River shelf sediments (NW Spain).

Microplastics (<5 mm; MPs) are globally recognized as an issue of emerging concern in the marine environment. In this study, MPs were determined for the first time in sediments from Rias Baixas and Mino river shelf, to show the baseline contamination levels. The Rias is well known for its intense fishing and shellfish harvesting activities. The sampling stations were selected due to their different exposure to anthropogenic activities and/or pressures. Sediment samples were collected using a box corer dredge and analyzed with density separation and μF-TIR analysis to determine polymer type. The results showed MPs pollution in all stations. The mean concentration was 70.2 ± 74.2 particles/kg DW. The main MPs shape was fibers (88.8%) followed by fragments (5.80%). Regarding the polymers, the most abundant were PP (43%) and HDPE (29%). Once again, MPs are ubiquitous all along Rias and Mino river mouth as previously shown in different works.