Some pollutants may also be transported by coastal currents along the shelf. Dissolved pollutants are carried even farther, as the river runoff leaves the shelves and flows across the central Arctic basin in the Transpolar Drift Stream. However, it is five times larger than the Mediterranean, which is the largest sea. In addition to rivers, ocean currents also transport contaminants into the Arctic Ocean. The main inflow of water is via the Norwegian Current into the Barents and Kara seas, and via the West Spitsbergen Current through Fram Strait into the Arctic Ocean.
Pollutants can enter the Arctic Ocean through the Bering Strait, between Alaska and Russia.
Export of surface waters from the Arctic occurs through the East Greenland Current, which transports water and sea ice through the Fram Strait and south along the Greenland margin.