Microplastics in surface sediments in Norwegian marine settings - abundance and geographical distribution

Abstract

Marine sediment samples from the Norwegian Sea in the south to a Barents Sea fjord in the north were analysed for contents of microplastic particles (10 µm - 5 mm). The top 3 cm sediments were used. Sediment characterization included grain size analysis, organic carbon, total-carbon, and carbonate content. Microscopy, combined with hot needle technique, demonstrated presence of microplastics in all samples, varying from 23 to 391 particles pr. kg sediment dry weight. Higher abundance of microplastic particles at the southernmost locations in the Norwegian Sea was observed compared to locations further to the north. Several factors may explain the geographical differences in microplastics abundance:1. Sediment grain size distribution suggests higher numbers of microplastics in fine-grained sediments.2. Higher abundance of microplastic particles at Norwegian Sea locations compared to fjord locations in the north may be caused by higher human population and activity at sea compared to further north.