Arctic Contaminant Distribution

Introduction

Until recently, many have thought of the Arctic as remote and pristine, far from the environmental problems associated with industrial and agricultural development in lower latitudes. The Cold War cloaked many activities in the region in secrecy, and for much of the world the Arctic remained out of sight and out of mind.

First indications that the region was not so remote from our activities came more than twenty years ago with the discovery of a thick layer of winter air pollution over the Arctic. This haze, which covers a region the size of Africa, is attributed to industrial pollution emanating primarily from Eurasia (Barrie and Bottenheim 1991; Shaw 1991; Sturges 1991). North American air pollution is transported to the northern Atlantic Ocean, Greenland, and Canada. Many of Eurasia' s industrialized sites lie under major air pathways that transport local pollution to the central Arctic. That areas of Eurasia north of 60 degrees are highly industrialized still surprises most people in the western hemisphere, who perceive the Arctic as a vast, white, clean wilderness inhabited by Inuit, polar bears, and whales. In part, this vision holds true for the North American Arctic, yet just across the ocean that both separates and binds the eight arctic nations lies the industrialized Eurasian Arctic, which comprises more than half the arctic coastline.

With the ending of the Cold War, we have learned that more than 50% of the rivers of the former Soviet Union (FSU) are polluted with PCBs, DDT, heavy metals, and viral contaminants (Feshbach and Friendly 1992; Environmentallssues 1993). These pollutants contaminate the coastal regions influenced by rivers, and some also may be transported across the Arctic by ocean currents and sea ice. Recently released information on intentional dumping of nuclear materials in Siberian seas (Yablokov et al.1993) raises even more disquiet about pollution of the arctic marine environment.

For years, Scandinavia has been concerned about transboundary pollution in the Arctic. Atmospheric pollutants emanating from the Kola Peninsula in present-day Russia have placed the once-pristine forests of northern Finland, Sweden, and Norway under stress. In response, Scandinavian governments initiated the process leading to the Arctic Environmental Protection Strategy (AEPS). In 1991, recognizing the unique vulnerability of the Arctic to transboundary environmental pollution, the eight arctic nations signed the AEPS.

An analysis of the documents produced for the AEPS convinced the Environmental Defense Fund (EDF), an American environmental organization, that the magnitude of transboundary pollution and its effects on the ecosystems of the North could be understood only by constructing maps of the various contaminants and their concentrations in the air, snow, water, ice, flora, and fauna of the Arctic. Funded by the U.S. Department of State, EDF collected more than seventyfive published papers from research institutions and government agencies working in the arctic region and used the data to compile a set of about 100 maps.

Draft maps, showing all data at the same scale, are now being finalized. The complete set of data—colour maps, data files, references, and brief text accompanying each map—will be reviewed by other experts. In this paper, we present the preliminary results from our initial compilation of data on the contamination of air, water, and ecosystems and show two maps as examples: DDT in beluga and PCBs in polar bears.

Our goals are to illustrate the current distribution of pollutants, to identify sigluficant data gaps, and to indicate where monitoring prograrnmes are required. This research is ongoing, and the data and analvsis must be viewed as work in progress.

Data Types and Caveats in Data Interpretation

Data were collected primarily for the central Arctic, but in some cases we also have included data from peripheral regions to allow easy comparison. Where a range of values was presented in the original report, we have used the average of the range.

Ensuring the quality and comparability of data between laboratories and methods is difficult; however, we hope that the new sampling guidelines developed by the Arctic Monitoring and Assessment Programme of the AEPS will rectify this problem. The data presented in the EDF maps are the best available, but there are many caveats in the interpretation of these data. Because none of the maps has enough data to illustrate the changes in concentrations of pollutants through season or time, we have included all the data for one topic on one map. Generally, we drew from data collected in the 1980s and 1990s; in a few cases, where no otherdata were available, we also used information collected in the 1 970s but published after 1980.

Interpreting pollutant loadings in animals requires information on age, sex, and migration patterns, which may not have been obtained or may not be easily determined. For this reason, the data must be interpreted with care.

Arctic Air Mass
Shown in yellow is the average extent of the arctic air mass bounded by the atmospheric arctic front in January (from Barrie and Hoff, 1984). The main zones of air flowing into and out of the arctic region in winter are shown by the orange bands with red arrows. (from Raatz, 1991)

Pollution in Air, Ice, Water, and Animals

Sources of pollution in air and water in the Arctic are as varied as the businesses, industries, and life-styles that produce the pollutants. Although it may seem that some pollutants occur only in air and others only in water, the distinction is not that clear. In fact, many of the chemicals usually associated with water pollution (e.g., lead and other metals) also may be found in air pollution.

There are, however, a few generalities that hold true most, if not all, of the time. Pollutants produced as gases (carbon dioxide, methane) remain in the air unless the air emission is bubbled through water and the gas dissolves, as would sulfur dioxide. Some gases dissolve in cloud droplets and then pollute rain, as in acid rain. Other pollutants—which may be particles such as ash, very small particles of metals and other solids, or chemicals attached to or associated with larger particles—may be emitted into the air along with gases and water vapor. PCBs and some other organic pollutants can exist as gases or can be attached to dust and dirt particles in the air.

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 while suspended in the water.

Air Pollution

Since the 1970s, investigators have noticed elevated concentrations of carbon, sulfur dioxide, sulfate, and heavy metals in the arctic atmosphere, producing air pollution known as arctic haze (Barrie and Bottenheim 1991; Shaw 1991; Sturges 1991). Data on sulfate in air show high concentrations in both eastern and western Europe, in the FSU, in the eastern United States, and in Canada. We do not have these data for much of Russia; however, data for southern and western Russia suggest high concentrations of sulfate in the atmosphere. The average fall-winter-spring concentration of sulfate in the Arctic extends in a plume over the North Pole from Eurasia to Svalbard, parts of Greenland, Alaska, and Canada.

What happens to the contaminants in this tongue of arctic haze after it leaves its source and heads across the North Pole? The physics of the deposition of contaminants from the atmosphere during the cold arctic winter and spring are not well understood, but we are compiling data on the contaminant levels in snow that may illustrate the regional patterns of deposition.

Sea Ice

Growing concern about pollution of the air and water may have missed a key element in the transport of pollutants—sea ice. The redistribution of pollutants by sea ice is poorly understood, but may prove important in the arctic environment. Much of the ice in the central Arctic is formed in the marginal seas, especially in the wide Siberian shelf seas such as the Kara and Laptev. Sea ice can incorporate contaminants from the water column, from airborne fallout, and from sediments in shallow waters. Sea-ice floes are transported thousands of kilometres through the arctic region over several years, and accumulated contaminants may be released into the ocean as the ice thaws, re-freezes, and thaws again.

Ice pressure ridges and icebergs gouge the sea floor in shallow marginal seas. Sea-ice pressure ridges on the Siberian shelf have drafts up to 25 metres and in the central Eurasian Arctic drafts of 43 metres have been documented. Recent iceberg gouging in the Barents Sea has reached water depths of 125 to 130 m, but generally is more shallow. The gouging may penetrate the sea floor to a depth of more than 5 metres, with a path 5-10 metres wide. Given the shallow depths of the majority of Russian radioactive dump sites, there is a real danger that ice gouging has damaged or will damage the waste containers, releasing radioactive materials into the sea.

Water Pollution

Transport of contaminants in water—including rivers, shallow seas, mid-, deep-, and surface-water currents of the Arctic Ocean, and sea ice—is an important factor in the redistribution of pollutants in the Arctic. Because data on contaminants in sea ice and the deep sea are so sparse, the following section focusses on the distribution of some contaminants in estuarine and surface ocean environments.

Fresh water runoff from arctic rivers has a dramatic effect on the arctic environment. More than half of the arctic seas are strongly influenced by river outflow. Fresh water drained from the continents is discharged by runoff from the Ob, Yenisey, Lena, Kolyma, and Mackenzie rivers. As a result of fresh water inflow, much of the surface water of the Kara, Laptev, East Siberian, and Beaufort seas have low salinities. Where actual contaminant data are sparse, the pattern of river runoff helps us to predict where riverine pollutants will be distributed.

Many FSU rivers are polluted with heavy metals, organochlorines, pesticides, radioactive waste, and viral contaminants (Feshbach and Friendly 1992; Environmental lssues 1993). The entire Yenisey River, a major section of the Ob, and parts of the Lena and Kolyma rivers are considered to be the most polluted. We have found very few data for pollutant levels in the FSU rivers; however, some data are reported in the State of the Arctic Environment Report (1991) and by Melnikov and Vlasov (1992) and Shiklomanov (1993).

Other major contaminant pathways into the Arctic Ocean include transport from the North and Baltic seas via the Norwegian Current into the Barents Sea, and via the West Spitsbergen Current 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). Pollutants also may enter the Arctic Ocean through the Bering Strait. Export occurs through the East Greenland Current, which transports water and sea ice through the Fram Strait and south along the Greenland margin. Water and sea ice also are discharged into Baffin Bay through the Canadian Archipelago.

Polychlorinated Biphenyls (PCBs) in Estuaries and Sea Water

Data on concentrations of PCBs are available for nearshore waters off the coasts of Siberia and Japan, in the North Sea, off Greenland, and along sections of the Canadian coastline. Elevated concentrations are observed in some of the bays in the Kara and Laptev seas (10,000 pgA, Melnikov and Vlasov 1992). This concentration is 10 times the U.S. Environmental Protection Agency standard for fresh water. McCrea and Fischer (1986) also noted levels of PCBs in Ontario rivers that drain into Hudson Bay in excess of 5,000 pgA. How much these polluted coastal waters influence the Arctic Ocean is not known because there are virtually no data from the central Arctic Ocean. Much lower values are observed near the Canadian Arctic Islands (Hargrave et al. 1988) and eastern Greenland (Gaul in press).

Dichlorodiphenyltrichloroethane (DDT) in Estuaries and Sea Water

The concentration of DDT in water has been measured off Siberia and Japan, in the North Sea, at various locations in the Atlantic Ocean, along transects in the Pacific Ocean from the Bering Sea to northern Japan, and off Canada and Greenland. The highest concentrations are reported near the Ob River in the Kara Sea (2,000 pgA) and near the Indigirka River in the East Siberian Sea (2,500 pg/l, Melnikov and Vlasov 1992). We do not have data on the concentration of DDT in the central arctic region.

Hexachlorohexanes (HCH) in Estuaries and Sea Water

In comparison to other organochlorines, HCH has been measured fairly extensively in circumpolar arctic waters. Values around 5,000 pg/l are observed in the Beaufort Sea (Hargrave et al.1988). Similar values in the northwest Pacific are suspected to originate from the lower and mid-latitude countries of Asia (Tanabe and Tatsukawa 1980). We do not have data on the concentration of HCH in the central arctic region.

Cadmium in Estuaries and Sea Water

Cadmium (Cd) occurs naturally and also is released by human activities. The widespread distribution of Cd from all sources makes it difficult to obtain absolutely Cd-free materials and chemicals for laboratory analyses. Consequently, the contamination of samples may be a problem.

Relatively clean surface ocean water is observed in the vicinity of Svalbard (Mart 1983). Reported concentrations of cadmium in some Russian estuaries are higher than in the Baltic. There are noticeable gaps in data for the central Arctic Ocean.

Lead in Estuaries and Sea Water

The distribution of lead in arctic waters is similar vo the distribution of cadmium. Lead also occurs naturally in the environment and is released by human activities. For example, widespread distribution of lead resulted from its use in gasoline. As with cadmium, the contamination of samples, particularly in glass, is a major concern.

Elevated concentrations of lead are reported from the Ob and Yenisey river estuaries (ca. 2,000 ngA (=2 ppb), Melnikov 1991). This concentration, although less than EPA criteria to protect human health, approaches the lead criterion for marine waters (5.6 ppb) to protect marine animals (Agency for Toxic Substance Disease Registry 1993). McCrea and Fischer (1986) found elevated concentrations in the Ontario rivers that drain into Hudson Bay of about 1,000 ng/l. Gaps in the data for the central Arctic make it difficult to assess the potential transport of polluted surface water to this region. Relatively clean surface ocean water is observed in the vicinity of Svalbard (Mart 1983).

Contaminants in Fauna - Bioaccumulation

One of the greatest problems with some pollutants is their tendency to accumulate in animals, including humans. The term for this process is "bioaccumulation," which refers to the ability of a chemical to accumulate in living tissues at concentrations higher than expected, given the properties of the chemical. Bioaccumulation of pollutants can take place from water, food, or air and often from more than one source. The chemicals that show greatest bioaccumulation are those that do not dissolve in water, but do dissolve in fats and oils; for example, the dioxins and PCBs. Hence, more of these pollutants are found in the fat of animals than in the muscle.

In extreme cases, this accumulation of pollutants also may be greater in carnivorous animals high on the food chain, such as meat-eating birds and humans. Toxic chemicals taken up from underwater sediments by small fish are passed on to predatory fish. Mammals and birds that eat these fish will, in turn, accumulate even greater concentrations of the chemicals. To make matters worse, the chemicals that accumulate and concentrate also remain in living tissues the longest—some for decades.

Contamination by organochlorines and heavy metals has been observed in many arctic flora and fauna. Because arctic countries generally have not co-ordinated their sampling programmes, however, some species have been analyzed only in one or two countries. Here, we examine some organochlorines measured in beluga and polar bears.

Dichlorodiphenyltrichloroethane (DDT) in Beluga

DDT in beluga generally ranges from 1 to 5 ug/g in the Alaskan and Canadian Arctic (Muir et al. 1990; Careau et al. 1992; Schantz et al.1993), about one million times higher than DDT levels in water. An average of 58 ug/g was measured in beluga from the St. Lawrence estuary, a high value indicative of past heavy use of DDT as a pesticide in eastern Canada (Muir et al. 1990). New data indicate that the White Sea is similar to the St. Lawrence estuary with a value of 64 ug/g (Muir and Norstrom 1993).

DDT in Beluga
DDT in Beluga and the southern limit of generalized Beluga range (dashed line). DDT data are compiled from Muir et al.(1990), Careau et al.(1992), Muir and Norstrom (1993), and Schantz et al.(1993). Data are missing from large areas of the Arctic.

Beluga Distribution
Generalized geographic range of Beluga and regions of Beluga concentration in autumn from the Atlas of Northern Ice Covered Regions (1980).

Polychlorinated Biphenyls (PCBs) in Polar Bears

PCBs in the fat of polar bears have been studied relatively thoroughly in the Canadian Arctic. Here, values are less than 10 ug/g (Norstrom et al. 1988). On Svalbard, the levels range from 2.9 to 90 ug/g wet weight (Norheim, Skaare, and Wiig 1992). These values are quite high compared to the U.S. Food and Drug Administration (FDA) recommended values to protect humans from consumption of contaminated food (Agency for Toxic Substance Disease Registry 1993).

In the 1970s, data also were reported from Alaska (Lentfer 1976), Canada (Bowes and Jonkel 1975), and westem Greenland (Clausen and Berg 1975). Recently, more data have been collected in Canada, Greenland, and Svalbard.

PCBs in Polar Bears
PCBs in polar bears and the generalized distribution of polar bears (dashed line). PCB data are compiled from Norstrom et al.(1988) and Norheim et al.(1992). Data are missing from large areas of the Arctic.

Distribution of Polar Bears
Polar bear distribution pattern and location of denning sites from Stirling (1990).

Conclusions

Industnal and agricultural activity, coupled with environmental negligence, in regions within and outside the Arctic has contnbuted to contamination that accumulates in the arctic food chain. A lack of data often makes it difficult for scientists to detennine the source of the pollution. In particular, tracing the transport of pollutants across the Arctic and determining their fate is hindered by significant gaps in data for the central Arctic Ocean. The Arctic Monitonng and Assessment Programme has a mandate to take inventory of sources, to detennine transport pathways, and to follow contaminants from their sources through the food chain. If the AMAP is to accomplish these tasks and produce a state-of-the-Arctic environment assessment useful to policy makers, it will need funding for expanded national and intemational monitonng prograrnmes.

Stephanie Pfirman is with the Environmental Defense Fund and the Department of Environmental Science, Barnard College, Columbia University, New York, USA.

Kathleen Crane is currently with the Naval Research Laboratory, Washington, D.C., USA. She is also associated with the Environmental Defense Fund, the Department of Geology and Geography, Hunter College, CUNY, and the Lamont-Doherty Earth Observatory, Palisades, New York, USA.

Peter deFur is with the Environmental Defense Fund and the Centre for Environmental Studies, Virginia Commonwealth University, Richmond, Virginia, USA.