Burning trash, Ísafjörður, Iceland. Photo: Bjarki Sigursveinsson, Flickr
While climate change and carbon have stolen the limelight in recent months, there has been little attention paid to Persistent Organic Pollutants—also known as POPs. As the name suggests, POPs are environmentally persistent, which means that they take a long time to degrade and can be transported over long distances. Due to the environmental conditions in the Arctic, they often end up “trapped” there.
Many of the chemicals classified as a POP were widely used globally in commercial products, in particular as pesticides and insecticides. The most well known pollutants include polychlorinated biphenyls (PCB), widely used in plastic products, and dichlorodiphenyltrichloroethane (DDT), which in some countries is still used as protection against malaria, typhus, and other diseases spread by insects. Despite the implementation of the 2001 Stockholm Convention on Persistent Organic Pollutants, in some parts of the globe they remain in use even today.
Pollution from afar
In the 1970s and 1980s, high levels of POPs were unexpectedly found in the Arctic, far away from the main sources of these pollutants. This discovery played a substantial role in the adoption of the 1998 Aarhus Protocol on Persistent Organic Pollutants1)Protocol on Persistent Organic Pollutants (POPs) (1998). Aarhus: UNECE on which the Stockholm Convention was built a few years later. In paragraph 3 of its preamble, the 2001 Stockholm Convention recognizes the vulnerability of Arctic regions, “Acknowledging that the Arctic ecosystems and Indigenous communities are particularly at risk because of the biomagnification of persistent organic pollutants and that contamination of their traditional foods is a public health issue.”
POPs can be produced and released by mines, military sites, smelters, power stations, and a variety of other sources. However, few of the pollutants actually originate in the Arctic. They are transported over long distances via air, water, and to a lesser extent migratory species, from regions further in the south. Once in the Arctic, the special environmental conditions tend to “trap” the pollutants as the cold favors their persistence compared to warmer environments. POPs are also stored and concentrated in animals’ fatty tissues through a process known as bioaccumulation. They are then passed on from one species to another, and accumulate over the length of the food chain, through another process known as biomagnification. Predator species higher up in the food chain, such as seals, bears or toothed whales, have potentially very high levels of pollutants. They are also often sources of sustenance for people living in the north. These twin processes create a situation where even a small amount of POPs can have important consequences for the larger arctic ecosystems.
A brief history of progress thus far
The Arctic Environmental Protection Strategy (AEPS), also referred to as the Finnish Initiative, was the precursor of the Arctic Council. One of the main reasons for its establishment by the eight arctic states in 1991 was a series of scientific studies that found high levels of POPs and heavy metals in northern communities. Under the AEPS, five different working groups were established, such as the Arctic Monitoring and Assessment Programme (AMAP), which monitors pollutants including POPs in the air, water, and biota in the Arctic.
Environmental concerns over the pollution of the arctic environment was one of the main drivers behind the subsequent establishment of the Arctic Council in 1996. The Arctic Council has since developed a long history of advocating for the resolution of environmental issues. During Finland’s Chairmanship from 2000 to 2002, for example, the Arctic Council was active in the negotiations of the Stockholm Convention on Persistent Organic Pollutants. Later, during the Icelandic Chairmanship from 2002 to 2004, it played a vital role in the implementation of the Convention.
Its current role in the elimination of POPs in the Arctic is less clear. In the last few years, it seems that the interest in POPs on the part of the Arctic Council has considerably decreased. Under the current U.S. Chairmanship for example, so-called short-lived climate forcers (SLCF) such as methane or soot are emphasized to the detriment of POPs and other pollutants.
In contrast to the resolutions of the Arctic Council, the Stockholm Convention is a legally binding international agreement on a global level. It was adopted in 2001, entered into force in 2004, and is managed by the United Nations Environment Program (UNEP). Starting with a “dirty dozen” of chemicals, and after thorough research and several amendments, the Stockholm Convention currently recognizes around 30 POPs. 2)Listing of POPs in the Stockholm Convention.
As of today, 179 parties have ratified the Convention, including the eight arctic states with the exception of the United States. Denmark ratified, but excluded the territory of Greenland and the Faroe Islands from the provisions. Canada and Russia did ratify the original treaty, but not its subsequent amendments listing additional pollutants, such as endosulfan and HBCD, as POPs.3)Amendments to Annexes to the Stockholm Convention. Nairobi: UNEP
While the United States has until now refused to ratify the Stockholm Convention, it has implemented several measures against POPs. It signed the bilateral agreement with Canada for the Virtual Elimination of Persistent Toxic Substances in the Great Lakes, the regional protocol of the United Nations Economic Commission for Europe (UNECE) on POPs under the Convention on Long-range Transboundary Air Pollution and provided ample financial and technical support to countries across the globe supporting the reduction of POPs. The use of the original “Dirty Dozen” is banned within the United States, but several substances more recently added to the Stockholm Convention, such as different flame retardants, continue to be used. Moreover, some of the chemicals, such as chlordane, are still manufactured for export.4)Margret Morales (2014) The Stockholm Convention. Durham: Duke University
The stalemate in the ratification process continues despite many years of activism from Indigenous communities in the Arctic. In an open letter to the Alaska Dispatch, Vi Waghiyi of the traditional Yup’ik community in Savoonga Alaska writes: “The United States is one of only a handful of nations which have not signed the Stockholm Convention, and so is not bound by this latest ban. The U.S., along with Canada, remains the highest user of this toxic chemical [PCP or pentachlorophenol].”5)Vi Waghiyi (2015) “An Arctic thank you for UN action against toxins that accumulate in traditional food.” The Alaska Dispatch, 7 July, www.adn.com/commentary/article/arctic-thank-you-un-action-against-toxins-accumulate-traditional-food/2015/07/08/
While the U.S. Senate has not ratified the Convention, the U.S. still participates as an observer in meetings and in technical working groups. Not being party to the treaty, however, also has its drawbacks, as the United States is not able to participate in decisions on the inclusion of additional substances to the Convention—something that worries the U.S. Environmental Protection Agency (EPA) as well as chemical industry groups.6)Elana Schor (2010) “Obama Admin Steps Up Pressure to Ratify Treaties on Toxics.” The New York Times, September 24, www.nytimes.com/gwire/2010/09/24/24greenwire-obama-admin-steps-up-pressure-to-ratify-treati-73636.html. Furthemore, the necessary legislative changes to the Toxic Substances Control Act (TSCA) and the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) prove to be extremely challenging despite serious attempts by several governments.
As one of the stated goals of the U.S. chairmanship of the Arctic Council is to improve living conditions in the Arctic—of which POPs undeniably have an impact—it is unclear how progress will be made in the current political climate.
Effects on the environment
A review of scientific studies focusing on the period from 2002 to 2009 concludes that tissue concentrations in several arctic species exceed a POP threshold of concern, which is set at 1 part-per-million (ppm). The Arctic populations having the highest risk potential include polar bears, killer whales, ringed seals, several species of seabirds, such as gulls, as well as a few populations of Arctic charr and Greenland shark.7)Letcher et al. (2010) Exposure and effects assessment of persistent organohalogen contaminants in arctic wildlife and fish. Science of the Total Environment 408(15): 2995-3043. In spring, which is a critical period for reproduction for many species, the melting ice and snow release the accumulated POPs into the environment. They are in turn ingested by wildlife. In winter, through the metabolism of fat reserves, in which they accumulated, the POPs are released and impact the organism.
The impacts on wildlife include:
- the interference with sex hormones, disturbing the reproduction cycle;
- the weakening of the immune system due to POPs’ impact on the thymus, an organ of the immune system that normally produces antibodies;
- an increased risk of tumors through damaged DNA;
- an increased risk of porphyria, a group of diseases in which the chemical substance porphyrin accumulates in the body, due to POPs’ effect on the production of red blood cells.
One example of a highly affected species is the wild reindeer, also known as caribou in North America. A study published last year in the journal Chemosphere found flame retardants—in this case polybrominated diphenyl ethers or PBDEs—in the feces of wild reindeer on Svalbard and in one of their favorite foods: moss.8)Wang et al. (2015) Characterizing the distribution of selected PBDEs in soil, moss and reindeer dung at Ny-Ålesund of the Arctic. Chemosphere 137: 9-13. Brominated flame retardants (BFRs) were recognized as “new” POPs in the last few years. They were extensively used for several decades in a wide range of commercial and household products, from plastics to textiles and electronic equipment, and can be released into the environment during production, use, or dismantling of the products. The susceptibility of reindeer to POPs is not new. A 1997 study by AMAP already pointed to the accumulation of PCB over the food chain. Compared to the contaminated lichen, caribou in Canada’s Northwest Territories feeding on that lichen had 10 times its PCB levels. At the next level in the chain, PCB in wolves was 60 times that of the lichen at the bottom of the food chain.
Other species that have been victims of POPs are peregrine falcons and other birds of prey. Nesting along the Yukon River, their exposure to DDT during their migrations south led to a thinning of the eggshells and harmed reproduction. Peregrine falcons were classified as endangered in 1971, but recovered soon after DDT was banned. They were eventually delisted in 1999. This example demonstrates how dramatic the effects of persistent organic pollutants on wildlife or health in general can be. A paper recently published in The Journal of Wildlife Management further underlines the importance of long-term monitoring to a comprehensive understanding of the ramifications of diverse substances on the environment.9)Ambrose et al. (2016) Recovery of American peregrine falcons along the upper Yukon River, Alaska. The Journal of Wildlife Management 80(4): 609-620.
A health threats to northerners
In addition to contributing to declines, diseases, and various abnormalities in wildlife species, persistent organic pollutants also represent a serious threat to human health and well-being. Similar to many animal species, their effects on humans include the promotion of certain types of cancers, birth defects, dysfunctional immune and reproductive systems, damage to the nervous system, and a generally higher susceptibility to diseases through a weakened immune system. Human exposure to POPs is mainly through contaminated food or through the transmission to future generations through the placenta and breast milk.
The high levels of POPs are especially dangerous in traditional subsistence foods in the Arctic, many of which are high up the food chain, rich in fat, and therefore rich in POPs. Marine and other mammals at the top of the food chain that contain high levels of POPs are traditional northern foods and central to the diets of Arctic Indigenous peoples. Furthermore, food prices in the North are high, which is why the local population relies more on subsistence foods and as a result are more exposed to the harmful effects of persistent pollutants.
Remobilizing POPs: the effects of climate change
After initial decreasing trends, higher levels of gexachlorobenzene and PCBs, whose use has been restricted and which are no longer produced, were observed in the Arctic in the mid-2000s. The ACIA report of 2004 warns that warming probably speeds up the transport of pollutants to the Arctic and increased precipitation would lead to more POP deposits in the Arctic. In addition, the melting of snow, ice, and permafrost, releases the contaminants accumulated over decades in the form of melt water, which will then enter the food chain. The increased frequency of forest fires due to climate change could also release increasing amounts of pollutants into the air.10)Muir et al. (2010) Trends of legacy and new persistent organic pollutants in the circumpolar arctic: overview, conclusions, and recommendations. Science of the Total Environment 408(15): 3044-3051.
POPs have low water solubility. They are harder to dissolve in water and evaporate more easily. As a result, they bond strongly to particulate matter in aquatic sediments, which can serve as “sinks” for the pollutants. If the ecosystem is disturbed, such as in the case of global warming, these trapped POPs might be released. Because they are semi-volatile, they can further evaporate out of their storage if temperatures are warm enough. By contrast, in colder temperatures, these chemical compounds are less volatile. While the degradation of POPs is temperature-dependent, which suggests that they are likely to degrade faster in warmer temperatures—which would be beneficial—this factor is deemed as less influential.
Indirectly, climate change affects POP levels by causing changes in patterns of Arctic land use and emissions, increased activity in the Arctic such as mining or shipping11)Hung et al. (2016) Temporal trends of Persistent Organic Pollutants (POPs) in Arctic air: 20 years of monitoring under the Arctic Monitoring and Assessment Programme (AMAP). Barking, Essex. or changing wildlife migration routes. The Pacific salmon, for instance, may move northwards into arctic rivers. Changing bird migrations can also transport POPs from marine to freshwater environments, where they might concentrate, as was the case in a specific watershed at Lake Ellasjoen on the Svalbard archipelago. Diseases and the spread of invasive species that are due to climate change, as well as diet shifts and nutritional changes, for example through temporal shifts in the diet of polar bears due to earlier ice break-up, can affect the distribution of the contaminants in the ecosystem and individual animals.12)Muir et al. (2010) Trends of legacy and new persistent organic pollutants in the circumpolar arctic: overview, conclusions, and recommendations. Science of the Total Environment 408(15): 3044-3051. Climate change may thus reduce the efforts and effectiveness of the Stockholm Convention.
Recent trends and continuous monitoring
In the Arctic, long-term monitoring of POPs takes place in Canada, Iceland, Svalbard and Finland. In the Russian Arctic, monitoring of POPs previously had only been performed on a campaign basis covering periods of one to two years. Now, two POP air monitoring stations are being established.
Recent studies have witnessed that the levels of many POPs have decreased in the Arctic, reflecting their ban in the last decades under the Stockholm Convention or previous national or international regulations. However, this shows just how persistent the pollutants are and sheds light on the secondary emissions—that is emissions generated in atmospheric reactions between contaminants.13)Hung et al. (2016) Temporal trends of Persistent Organic Pollutants (POPs) in Arctic air: 20 years of monitoring under the Arctic Monitoring and Assessment Programme (AMAP). Barking, Essex.
The steadily increasing list of new chemicals of concern poses further financial and technical challenges to the sampling at monitoring stations and scientific analyses of samples. Some of the new chemicals of emerging concern are more volatile than most “legacy POPs”, which makes them more difficult to trace. As a result, their actual level might not be reflected in monitoring data. Many of them may also have emission sources in the Arctic, for example in homes or landfills, in addition to being used in commerce.
Research shows that the ban of certain POPs decades ago had positive effects on their levels in the Arctic and was very beneficial for wildlife populations and ecosystems. The ratification and implementation of the provisions of the Stockholm Convention, as well as the continuous update of the list of POPs should therefore prove favorable to the overall health of the population, in particular Indigenous peoples. The U.S., Canada, and Russia should follow the lead of other countries and practice what they preach by not only ratifying the Convention and phasing out these extremely harmful pollutants, but by also ratifying the amendments to account for additional pollutants of concern. The inclusion of Greenland is another missing piece in the puzzle. The results of such a comprehensive endeavor will take some time to materialize, but will certainly be worth the effort.
References [ + ]
|1.||↑||Protocol on Persistent Organic Pollutants (POPs) (1998). Aarhus: UNECE|
|2.||↑||Listing of POPs in the Stockholm Convention.|
|3.||↑||Amendments to Annexes to the Stockholm Convention. Nairobi: UNEP|
|4.||↑||Margret Morales (2014) The Stockholm Convention. Durham: Duke University|
|5.||↑||Vi Waghiyi (2015) “An Arctic thank you for UN action against toxins that accumulate in traditional food.” The Alaska Dispatch, 7 July, www.adn.com/commentary/article/arctic-thank-you-un-action-against-toxins-accumulate-traditional-food/2015/07/08/|
|6.||↑||Elana Schor (2010) “Obama Admin Steps Up Pressure to Ratify Treaties on Toxics.” The New York Times, September 24, www.nytimes.com/gwire/2010/09/24/24greenwire-obama-admin-steps-up-pressure-to-ratify-treati-73636.html.|
|7.||↑||Letcher et al. (2010) Exposure and effects assessment of persistent organohalogen contaminants in arctic wildlife and fish. Science of the Total Environment 408(15): 2995-3043.|
|8.||↑||Wang et al. (2015) Characterizing the distribution of selected PBDEs in soil, moss and reindeer dung at Ny-Ålesund of the Arctic. Chemosphere 137: 9-13.|
|9.||↑||Ambrose et al. (2016) Recovery of American peregrine falcons along the upper Yukon River, Alaska. The Journal of Wildlife Management 80(4): 609-620.|
|10, 12.||↑||Muir et al. (2010) Trends of legacy and new persistent organic pollutants in the circumpolar arctic: overview, conclusions, and recommendations. Science of the Total Environment 408(15): 3044-3051.|
|11, 13.||↑||Hung et al. (2016) Temporal trends of Persistent Organic Pollutants (POPs) in Arctic air: 20 years of monitoring under the Arctic Monitoring and Assessment Programme (AMAP). Barking, Essex.|