Аннотация:Rivers are a key pathway for the transport of plastics into the ocean. Studies of plasticpollution in Arctic rivers remain limited due to the inaccessibility of sampling sites and workin extreme weather conditions. This work presents the results of a three-year (2019–2021)survey of floating large microplastics (0.5–5 mm) and meso/macroplastics (>5 mm) in theNorthern Dvina River, an actively navigated river that drains a densely populated regioninto the White Sea. Sampling was conducted during the ice-free periods (May–October)along a ∼3.5 km transect using a Neuston net, providing a multi-year dataset spanningthree ice-free seasons. A critical methodological advancement was the calculation of plasticriver–sea flux using the discharge of the sampled surface layer (upper 20 cm), whichconstitutes only ∼3% of the river’s total discharge, rather than the total discharge itself.Observed microplastic concentrations (average 0.003 items m−3) were low compared tomany European rivers, and lower than those reported in the adjacent Barents and Kara Seas.Microplastic abundance was significantly lower during the high-water season than duringthe low-water season, which resulted in practically no seasonal variability in microplasticfluxes from the river to the White Sea (average 0.3 items s−1). A notable finding was that insome cases, meso/macroplastics outnumbered microplastics by item count, underscoringthe river’s role as a significant source of larger plastic debris. A geospatial assessment ofArctic rivers’ pollution potential was performed, using socio-economic indicators such asnear-delta population density and port activity. This study identified the Northern DvinaRiver as a major contributor of microplastics among the Arctic rivers.https://www.mdpi.com/2073-4441/18/8/955
