The Arctic at Risk:
A Circumpolar Atlas of Environmental Concerns

by Stephanie Pfirman, Kathleen Crane, Kim Kane, and Tania Simoncelli

Review Draft: Not for Citation

Water

Water pollutants include a variety of chemicals, including some gases and particles that are discharged or washed or that have fallen into rivers, lakes, or seas. The so-called "conventional" pollutants include the materials discharged from a sewage treatment facility: nutrients, bacteria, organic particles, sediment, and sulfur-containing compounds. In addition, many chemicals--such as road salts, detergents, cleaning compounds, some pesticides, and chemicals formed from heavy metals--dissolve readily in water. Still other chemicals do not dissolve in water and, once discharged, attach to a particle and either sink to the bottom or remain for some short period suspended in the water.

Transport of contaminants in water--including rivers, shallow seas, oceanic currents of the Arctic Ocean--is an important factor in the redistribution of pollutants in the Arctic. The following section focuses on the fate of contaminants in estuarine and surface ocean environments (less than approximately 200 meters water depth) both because data on contaminants in the deep sea are sparse, and because this shallow environment is most important for the marine food chain.

Rivers The Arctic watershed is huge, in Asia extending farther south than 50deg.N in some places. Freshwater drained from the continents is discharged primarily by the Yenisey, Lena, Ob, Mackenzie, Sv. Divina, Pechora, Kolyma, and Indigirka rivers. During winter, river runoff is reduced as the rivers freeze, although rivers with headwaters in lower latitudes and some groundwater contribution, such as the Ob', Yenisey and Mackenzie, maintain flow throughout the year. Runoff increases abruptly in May and June and continues through October. As a result of freshwater inflow, much of the surface water of the Kara, Laptev, East Siberian, and Beaufort seas have low salinities.

The Siberian rivers discharging into the Kara, Laptev, and East Siberian seas have a combined drainage area of 9,000,000 km2 (Shiklomanov and Skakalsky, 1994), encompassing many industrial and agricultural regions. As a result, more than 50% of the rivers of the former Soviet Union (FSU) are reportedly polluted with PCBs, DDT, heavy metals, and viral contaminants (Feshbach and Friendly, 1992; Environmental Issues, 1993). However, some of these reports may be compromised by poor data quality. For example, while some studies state that the Yenisey and Ob' are the most polluted of all the Siberian rivers (State of the Arctic Environment Report, 1991; Melnikov and Vlasov, 1992; Shiklomanov and Skakalsky, 1994), a recent study shows that the Ob' and Yenisey rivers are relatively clean with respect to cadmium, copper, iron, nickel, and lead (Dai and Martin, 1995).

Pollutants attached to particles often are deposited where the river water encounters seawater at the river delta or in the river estuary. 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. River water makes up about 10% of the surface waters in the Transpolar Drift Stream (Schlosser et al., in press). It takes less than eight years for most Siberian river water to move from the river mouth all the way across the Arctic to Fram Strait (e.g., Schlosser et al., in press).

Arctic Ocean The Arctic Ocean is the smallest of the world's oceans, encompassing a region of some 12,257,000 km2 (Encyclopedia Britannica, 1990). However, it is five times larger than the Mediterranean, which is the largest sea. Approximately 36% of its total area is underlain by continental shelf. Although the shelf is only 100 to 200 km wide north of Alaska, north of Siberia it extends over 1,600 km in some places (Encyclopedia Britannica, 1990). 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. High concentrations of pollutants in the Baltic and southern sections of the North Sea are well documented (Salomons et al., 1988) and may influence this inflowing current. Radionuclides discharged from the Sellafield/Windscale nuclear fuel reprocessing facility on the coast of England, and at Cap la Hague on the French Channel coast make their way into the Arctic through the Barents Sea and Fram Strait via the Norwegian Current.

Pollutants can enter the Arctic Ocean through the Bering Strait, between Alaska and Russia. In addition, airborne pollutants deposit on the sea surface or on sea ice, which then melts and releases its pollutant load to the surface ocean waters (Melnikov, 1992; Pfirman et al., 1995). 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. Approximately equal amounts of surface water are thought to flow out of the Arctic Basin through this strait and through the Canadian Archipelago, where the water enters Baffin Bay (Schlosser et al., in press). Fram Strait (sill depth 2,600 m) is distinguished as the only deep-water passage between the Arctic and the rest of the world's oceans.

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