A spatial and temporal assessment of microplastics in seafloor sediments: A case study for the UK

Seafloor sediments have been defined as sinks for microplastics in the marine environment and could therefore represent suitable matrices their long-term monitoring. On a regional aspect, adoption of common indicator seafloor would allow monitoring assessments through international frameworks such OSPAR. This study presents findings research development project occurrence abundance UK period 2013-2021, supporting national programme (England Wales). A fast-screening technique based on Nile Red staining polymers coupled with µ-FTIR was applied validated using µ-FTIR-FPA. Microplastic particles were detected all 189 sediment samples from 15 stations selected around each investigated year (2013 - 2021). concentrations (20 – 5000 µm) ranged 133 6,933 kg -1 dry weight 2020-2021. Microplastics mainly consisted fragments (73%), fibres (19%) spheres (8%). Plastic 46 to 3276 µm plastic 300 1731 length mean diameter 16 µm. Single particle analysis indicated prevalence Rayon, PP, Rayon/Nylon/Polyester blends, Rubber, PS, PE, PA, PVC, Acrylic, EMAA PET. Fragments white colour (46%) followed by brown (38%), black (1%), blue (1%) orange (1%). Fibres (57%) (14%), (14%) red (14%). trend assessment at seas levels little visual evidence any trends over time possible exception Northern North Sea reduction time-period 2013-2021.