Status and trends
Scientists and the authorities are concerned about the high concentrations of certain kinds of pollutants measured in the Arctic.
PCB values from air measurements at the Zeppelin Observatory in Ny-Ålesund in Svalbard show higher levels than at corresponding stations in Canada, suggesting that the European Arctic receives more PCB than the North American Arctic. The PCB levels in polar bears in Svalbard are 2–6 times higher than in polar bears from Alaska and Canada. The polar bear also has higher levels of certain kinds of brominated flame retardants.
Scientists have also found a number of “new” pollutants, like various types of brominated and fluorinated substances, in the air in Svalbard.
Air pollution
Atmospheric pollution is monitored in the Norwegian part of the Arctic at the Zeppelin Observatory in Ny-Ålesund. The monitoring focuses on compounds associated with acidification and top dressing, greenhouse gases, organic pollutants and heavy metals.
Acid precipitation
Acid precipitation was a major environmental problem until around the 1970s. The problem is caused by nitrogen and sulphur compounds in the atmosphere, and subsequent acid precipitation. Such precipitation caused forests to die, and top dressing could result in changes in the composition of the vegetation; for instance, moss could be out-competed by grass. Sulphur is a greater problem than nitrogen in the Arctic. Experience has shown that discharges from Russia and to some extent Eurasia are the principal sources of sulphur and nitrate compounds measured in the Norwegian part of the Arctic.
An evaluation in the 1990s revealed that about 5 % of ice-free areas with vegetation showed effects of acid precipitation. The discharges have been substantially reduced since then, and measurements of sulphur compounds at the Zeppelin Observatory showed a reduction of as much as 61 % from 1980 to 2010.
Heavy metals
Heavy metals are emitted in connection with traffic and industry. In nature, heavy metals affect both people and wildlife. For instance, lead is acutely toxic to aquatic organisms and mammals, harming foetuses and having immunological effects. The Zeppelin Observatory measurements show that lead levels were reduced by 30 % from 1994 to 2010. The shift from leaded to unleaded petrol contributed to this reduction worldwide. Measurements of cadmium and mercury do not show corresponding trends in the Arctic, probably because the global circulation patterns continue to supply the Arctic with these heavy metals from distant sources where industrial activity is high.
Persistent organic pollutants
Persistent organic pollutants (POPs) are a special problem for wildlife in the Arctic because they are fat-soluble and arctic animals are dependent upon stores of fat to insulate them against the cold. The POPs accumulate in the fatty tissue and are liberated to other parts of the body when the animal is starving or fasting.
POPs are measured at the Zeppelin Observatory, and 2011 stood out by having the lowest ever annual mean for several of the most common POPs, such as PCB?. HCB? has increased a little in Arctic air masses each year since 2007.
According to the Management plan for Lofoten and the Barents Sea (2010), these waters are clean and rich in life, and have a low level of pollution. The reprocessing plants for nuclear waste at Sellafield and Cap de la Hague are sources of technetium-99, a radioactive isotope?. Seawater in Kongsfjorden in Svalbard and off Jan Mayen is monitored to try to track nuclear waste emissions. Technetium-99 emissions rose greatly in the mid-1990s and this was reflected in the measurements, but they have declined since then.
Trends
The levels of contaminants in the Arctic vary in both time and space. Contaminants that are transported in the atmosphere follow the seasonal fluctuations of the air masses, and levels therefore vary through the year. The levels of other contaminants vary as a result of efforts made by management authorities through international conventions, for example, and we can consequently see declining trends of contaminants in the Arctic.
Organic pollutants
Time trends for organic pollutants in the Norwegian part of the Arctic vary considerably, depending upon the substances and where they are measured. The air measurements show a rising trend for HCB, varying trends for PCBs and declining trends for HCH, [tooltip id={chlordanes}]chlordanes[/tooltip] and DDT. No trends have been observed for PBDE, PFAS or TBA, which have been monitored in the air since 2006.
Compared with other parts of the Arctic, high PCB levels have been measured in the air and in lake sediments from Svalbard. The PCB levels in wildlife from Norwegian arctic areas show a declining trend. However, PCBs are still the predominant contaminant in the Arctic. Since PCBs degrade slowly, they will remain in the environment for many more decades. The chlorinated herbicides show more varying trends, but the main trend seems to be declining levels. Groups of brominated compounds like PBDE and PBB have been observed to be declining, whereas other brominated compounds like α-HBCD are rising. The time trends for fluorinated compounds in the Arctic are not clear and vary from one to another.
Management measures such as bans and phasing out lead to reductions in emissions and transport. Substances like PCBs and chlorinated sprays are decreasing because bans on their manufacture and use have been introduced, whereas concentrations are increasing for substances that have not been banned internationally, for instance HBCD and some of the fluorinated compounds. The “new” contaminants which are discovered in the Arctic give grounds for concern and show that more substances than the traditional persistent organic pollutants (POPs) have a potential for long-range transport. The concentrations of polluting substances which have been banned and phased out are expected to decrease in the future. However, the manufacture and use of new compounds is constantly increasing and these may affect the arctic environment.
Heavy metals
The heavy metals, cadmium, mercury and lead, are regarded as challenging for arctic areas. Mercury discharges have been reduced in North America and Europe since the 1990s, whereas they have increased greatly in Asia. The reduction in the use of leaded petrol has been very effective in reducing lead pollution. Changes in the concentration of cadmium and mercury have not been measured at the Zeppelin Observatory at Ny-Ålesund in Svalbard since measurements started in 1994, but lead has declined by 30 %. There are lower quantities of heavy metals in lake sediments from Svalbard than from mainland Norway. Mercury and cadmium levels in wildlife from Svalbard are generally lower than from other parts of the Arctic.
Radionuclides
De viktigste kildene til menneskeskapt radioaktivitet har vært globalt nedfall fra atmosfæriske kjernefysiske våpentester, utslipp fra gjenvinningsanlegg i Europa og Tsjernobylulykken. Utslipp fra alle atomanlegg til The most important sources of anthropogenic radioactivity have been global fallout from nuclear weapon testing in the atmosphere, discharges from recycling plants in Europe and the Chernobyl disaster. On the whole, discharges from all nuclear plants to northern European waters have been reduced since the early 1990s, and levels of radioactivity are continually declining. The expected trend in the years to come is that the levels of anthropogenic radioactivity will continue to sink.
Geographical trend in wildlife
The geographical trends found in the Arctic fox corresponds with the trends found in the polar bear, with the highest contaminant values in East Greenland and Svalbard, moderate ones in Canada and the lowest ones in Alaska. Recent studies have shown that the levels of contaminants in arctic foxes are strongly related to where in the food chain they find their food and the proportion of marine and terrestrial food items in their diet, that is to say where they spend most of their time and what they eat. Results from Svalbard show that the levels of contaminants are highest in arctic foxes which find food high in the marine food chain.
The geographical differences in arctic foxes can also be related to the two different types of habitat arctic foxes live in, inland and coastal habitats. Foxes which have mostly eaten animals living on land (for instance, ptarmigan and reindeer) have lower PCB levels than those which have eaten animals living in the sea (for instance, seals). The high levels of contaminants in arctic foxes in Svalbard and Iceland can be explained by them having a more marine diet than those in Canada and Alaska.
Global restrictions
Global restrictions and phasing out of a number of pollutants such as PCBs, DDT, HCH and some brominated compounds and PFOS have been introduced. Time-series measurements in air and birds show that these substances have declined following the introduction of the global restrictions, but they will not disappear from the arctic regions. However, the trend is the opposite for new, unregulated pollutants, whose levels are rising in both the air and organisms.
The quantity and distribution of pollutants in the Arctic have been studied for many years, not least through the Arctic Monitoring and Assessment Programme (AMAP), one of six working groups under the Arctic Council.
Norway’s position in the Arctic gives the country a unique opportunity to be a leading manager of the environment in northern areas since the discovery of new pollutants in the Arctic is most important for regulating chemicals. This regulation takes place under the terms of the Stockholm Convention, through the EU REACH programme.
Effects of pollutants
Effects of pollutants have been found in animals high in the food chains in the Arctic. Impacts on the hormone and immune systems, reduced reproduction and increased offspring mortality are some of the effects found in the polar bear, glaucous gull, arctic char and harp seal. Impaired immune system and reduced reproduction show that far-transported pollutants affect populations of arctic animals.
Seabirds
Glaucus gull and ivory gull eat fat from mammals with high concentrations of pollutants. Photo: Geir Wing Gabrielsen / Norwegian Polar Institute
A number of seabirds in the Arctic are high in food chains, even though they are not top predators. Some are carrion eaters and consume remains of marine mammals which have a high content of contaminants. Others, like the Brünnich’s guillemot, consume fat-rich fish like capelin, and also polar cod. Brünnich’s guillemot eggs were analysed for contaminants in 1993, 2002-2003 and 2007. The trends for PCBs, DDE (a breakdown product of DDT?) and toxaphene are declining, whereas HCB? remains unchanged. The glaucous gull is at the peak of the food chain. Measurements performed on glaucous gulls on Bjørnøya (Bear Island) from 1972 to 2006 revealed high levels of “old” organic pollutants, such as PCBs, DDT, chlordane? and HCB, and in part high levels of “new” pollutants such as brominated flame retardants and fluorinated compounds. The pollutant load has had significant consequences for the health of glaucous gulls on Bjørnøya in the Barents Sea. Effects have been demonstrated on the enzyme and immune defence systems, hormones, reproduction and survival. Some glaucous gulls on Bjørnøya eat large numbers of seabird eggs and chicks during the breeding period, and this part of the population is particularly exposed to the highest levels of contaminants. The most serious effects have been found in these birds, but negative effects in birds away from Bjørnøya have also been found.
Monitoring of seabirds has shown that the glaucous gull, great skua and ivory gull are at risk.
Glaucous gull
Research has revealed that the effects of a contaminant load on glaucous gulls involve changes in the liver enzyme activity, vitamins, hormones, immune system, metabolism and temperature regulation, regulation of genes, egg size, reproduction, behaviour and survival.
Birds with a high content of contaminants suffer disturbances in their hormones which change their breeding behaviour and thus affect the survival of their chicks. In addition, it has been found that the egg itself may be affected by the contaminant load in the mother, resulting in the egg being smaller and having less yolk, thus affecting the chick at the start of its life.
All told, the effects are a great burden for glaucous gulls, particularly in the breeding season. The glaucous gull population on Bjørnøya (Bear Island) has shown a negative development, declining by 60 % since the 1990s.
Ivory gull
The ivory gull is even more exposed than the glaucous gull since it feeds at several levels in the food chain, eating zooplankton, small fish and carrion from marine mammals. It therefore consumes fat from marine mammals with high concentrations of contaminants. Studies have shown that eggs containing a large amount of contaminants have thinner shells than normal and therefore break more easily.
As the contaminant level in ivory gulls exceeds that measured in glaucous gull eggs, it is possible that deleterious effects may also occur in ivory gulls, but this has not been investigated.
MOSJ (Environmental Monitoring in Svalbard and Jan Mayen) indicators:
Marine mammals
Polar bear
The polar bear is a predator at the peak of the marine food chain in the Arctic. It mainly eats seals, such as the ringed seal, which it hunts on the ice. Polar bears are extremely dependent upon sea ice for hunting and living on, and will be affected by changes in the ice. As a top predator in the marine food web, it is exposed to high levels of contaminants, especially the persistent organic pollutants. These are slowly degradable contaminants which are stored in fat and increase in concentration up the food chain.
Like the ringed seal, the polar bear is exposed to both pollution and decreasing sea ice. Effects from persistent organic pollutants have been demonstrated on the hormone, vitamin, enzyme, and immune systems of polar bears. This is a stress factor which may pose a threat to the population in Svalbard. In addition, it has been observed that higher mortalities of cubs coincide with higher contaminant loads in Svalbard and Franz Josef Land compared with Russia, Alaska and Greenland. This indicates that the reproductive ability of the polar bear may also be weakened by contaminants. Ringed seals form an important food item for polar bears, and they in turn feed on such creatures as crustaceans and polar cod. The content of contaminants in ringed seals was investigated in 1996 and 2004, and PCB levels fell significantly in this period.
In addition, it has been observed that higher mortalities of cubs coincide with higher contaminant loads in Svalbard and Franz Josef Land compared with Russia, Alaska and Greenland. This indicates that the reproductive ability of the polar bear may also be weakened by contaminants.
The sea ice is the most important polar bear hunting ground. The primary threat to the polar bear will therefore be global warming and melting sea ice. If these lead to food becoming less readily available, the concentration of contaminants may rise because the polar bear must turn to its body fat and burn that, but it is not clear how the contaminants will affect the bear in such periods. Changes in the type of prey due to altered habitat use may also result in changes in how the animals are exposed to different types of contaminants. Future studies will be able to reveal how levels and effects of different substances may be determined by changes in habitat use as a consequence of climate change.
MOSJ (Environmental Monitoring in Svalbard and Jan Mayen) indicators:
Ringsel
Nivåene av PCB, DDT, bromerte flammehemmere og toksafen er betydeligere lavere i ringsel fra Svalbard enn i ringsel fra Østersjøen. På bakgrunn av dagens miljøgiftnivå hos ringsel på Svalbard er det ikke grunn til å tro at miljøgifter har effekter på dyrenes immun-, hormon eller reproduksjonssystem. Men siden ringselen kan ha perioder med lite mat og at den taper vekt under pelsskifte (moulting) siden den spiser lite, kan det ikke utelukkes at miljøgiftene i disse periodene kan påvirke helsen til ringseler på Svalbard.
Den primære trusselen mot ringsel er, i likhet med isbjørn, global oppvarming som smelter havisen. Ringsel er avhengig av is for fødsler, diing, hvile og for skifte av ham. Ringselen bruker kun is når den ikke er i havet, den legger seg aldri på land. I tillegg bruker den områder dekket av is til næringssøk.
MOSJ (Environmental Monitoring in Svalbard and Jan Mayen) indicators:
Terrestrial mammals
MOSJ (Environmental Monitoring in Svalbard og Jan Mayen) indicators:
Fish
Polar cod and capelin are key species in the arctic ecosystem, and both are being monitored with a view to their contaminant load. Since both species are important food items for other fish-eating fish and for seals, whales and seabirds, this monitoring will provide better information about the bioconcentration up the food chain.
In general, the levels of organic pollutants are very low in both polar cod and capelin, and it is believed that neither of these species suffers any effects of a contamination load.
Sources and transport
The main sources of contaminants in the Arctic are regarded as being the fairly densely populated and industrialised parts of the world. The substances are transported to the Arctic in the atmosphere and by ocean currents, and also by rivers and ice in the Arctic. These are the most important means of transport, but pollutants carried by animals which move between the polar areas may also have some significance.
Sources
Contaminants are emitted into the atmosphere or discharged into the sea and are carried to the Arctic by winds and ocean currents, rivers and melting ice. Illustrasjon: AMAP
The main sources of contaminants in the Arctic are regarded as being the fairly densely populated and industrialised parts of the world. The substances are transported to the Arctic by winds and ocean currents. The contaminants are mainly accumulated in the marine food chains. The terrestrial food chains in the Arctic have low levels of contaminants. The Arctic functions in many ways as an indicator region for known and new contaminants. If a contaminant is discovered here, it is an indication that the substance is poorly degradable, is transported long distances and accumulates in marine food chains.
A few places in the Arctic have activities which may lead to local pollution of the environment. Rubbish and sewage from the settlements are a source for contaminants such as PAH?, PCB?, siloxanes and fluorinated compounds. Mining takes place in several parts of the Arctic, like Svalbard, the Pechenga-Nikkeli district and Siberia, and it represents a local source for contaminants such as PAH, heavy metals and PCBs.
The contaminants are transported to the Arctic by rivers, winds and ocean currents, and new substances are constantly appearing. Even the “old” contaminants which are no longer being manufactured or used can be stored in the environment (in the ground, ocean, glaciers, ice, water or animals) for many years and thus constitute a problem for nature and the environment for a long time. Old contaminants in the environment or in wild animals which live a long time may thus be a secondary source of pollution.
Transport by rivers and ice
Sediments from polluted rivers are sometimes frozen into the ice and transported over the Arctic Ocean to the Fram Strait, where the ice melts and liberates the pollutants.
Transport by ocean currents
Ocean currents move slowly, and transport of pollutants from industrialised and densely populated areas may take several decades. Pollutants which are soluble in water and are discharged straight into the sea, or land on the sea as rain, are transported northwards by the ocean currents. Depending on how soluble in water they are, the pollutants may become bound to particles and sink to the seabed. Some areas of this kind may become what are called sinks, repositories for pollutants.
SLOW PROCESS Transport of pollutants in the sea is a slow process and it may take years before they reach the Arctic. Photo: Ann Kristin Balto / Norwegian Polar Institute
Sea transport of pollutants to the Arctic is controlled by the current systems and the layering in the sea. Transport of pollutants in the sea is a slow process and it may take years before they reach the Arctic. They may then remain in the sea for a few years up to several centuries. Studies suggest that sea transport is the primary means of transport of PFOA? to the Arctic. It is also estimated that some 35 % of long-transported PCBs? reaching Svalbard do so via the sea.
Depending on how different radioactive substances behave in the marine environment, some may be transported by ocean currents over long distances. For instance, technetium-99, discharged into the sea from the nuclear fuel reprocessing plants at Sellafield and Cap de la Hague, may be traced along the entire North Atlantic coast right into the Barents Sea.
The slow movement of the ocean currents towards the pole also gives a time delay in respect to measures undertaken to prevent pollutants reaching the environment.
PFOA may occur in many products used on an everyday basis. The substance has water and fat repelling properties and is used as an impregnation agent to make products waterproof and dirt repellent. PFOA is toxic with repeated exposure, carcinogenic and may harm the reproductive system.
Atmospheric transport
MOST COMMON MODE OF TRANSPORT The atmosphere is the most common and quickest mode of transport for pollutants. Photo: Istockphoto
The atmosphere is the most common and quickest mode of transport for pollutants. It may take only a few days or weeks for the pollutants to reach the Arctic from certain areas. Volatile and semi-volatile compounds are transported in the atmosphere.
Airborne pollutants are carried to the Arctic on air currents in the atmosphere. For example, it is estimated that some 45 % of long-transported PCBs reach Svalbard by direct air transport. Some types of pollution, particularly volatile and semi-volatile organic compounds and mercury, are transported in gaseous form and behave differently from substances that are bound to particles and aerosols. As the temperature gradually drops, the pollutants become bound to particles or dust and fall to the ground as rain or snow. This process may be repeated through seasonal cycles, so that ice melting, autumn storms and other events whirl the particles up so that they may be transported further in the atmosphere. Persistent organic pollutants (POPs) and mercury can repeat this process many times and spread over the entire planet. However, the climatic conditions at high latitudes make it more difficult for them to convert into a gaseous form again when they have been precipitated so that they are easily accumulated in these regions.
The part played by the atmosphere as a means of transport varies from season to season. The transport is greatest in winter and spring, and least in summer, because the properties of the air masses differ in different seasons. The Arctic winter is characterised by a stable High over the North Pole which “captures” the air masses for a long period. The air therefore remains stable for a long time, giving plenty of time for pollutants to be deposited on ice, sea or land. In summer, temperature changes give the air masses more energy which, in turn, generates more dynamic weather instead of the static high pressure.
Climate changes that affect the weather systems may have an effect on one or more of the processes which control the transport or deposition of the pollutants. Much more needs to be learnt about this, and a great deal of research and modelling are taking place to elucidate the consequences of climate changes for the atmospheric transport of pollution. Existing knowledge suggests that POPs, for example, “captured” in water and ice will be revitalised in the atmosphere as the temperature rises, and there is evidence that such a process has already begun for some of the most volatile substances. A recently published study indicates that several POPs have been remobilised in the atmosphere during the last two decades as a result of climate change, and several other studies have shown that climate change has already had significant consequences for many aspects of the transport and remobilisation of mercury, partly in association with distribution and transport in the sea-ice-air interface. However, another recently published study indicates that the indirect consequences of climate change (changes in agriculture, utilisation of resources, etc.) will have at least as great an effect on the distribution and deposition of pollutants as the direct changes.
The Arctic Dome
Air currents transport pollution into the Arctic. The strong cooling around the North Pole in winter causes warm polluted air from lower latitudes to slide over the cold air so that the pollution is not deposited in the Arctic. This is called the arctic dome, because cold air forms a protective lid in the lower troposphere.
In periods with abnormal warming, such as the winter of 2006, this cold-air insolation fails to function and polluted air may penetrate into the central Arctic close to the surface and deposit pollution. If such warmer winters occur more frequently due to the retreat of the sea ice, the amount of deposited pollution may increase dramatically.