There are several classes of environmental contaminants that are most commonly studied in the Arctic: Persistent Organic Pollutants, heavy metals, and radionuclides.
Persistent Organic Pollutants (POPs)
These are toxins, often referred to by their acronym POPs, that accumulate and reside in the environment and in species for long periods of time. According to the U.S. Environmental Protection Agency, these toxins have been shown to adversely affect health in many ways. At certain levels, exposure to some of these pollutants can lead to cancer, as well as negatively affect the immune, reproductive, nervous and endocrine systems in humans
Arctic indigenous leaders played a key role in the creation of the Stockholm Convention, the international agreement for the elimination of POPs. The Convention notes that Arctic communities and ecosystems are especially at risk for exposure and contamination.
Characteristics of POPs include:
- Persistent: They last in the environment for long periods of time.
- Long-Range Transport: They are found far from where they were originally produced.
- Bio-accumulation: They become more concentrated as they move up the food web.
Types of POPs include:
- DDT: This is a popular pesticide used around the world. In the U.S. and Canada, production and use was stopped in the 1980s.
- PCBs: This is an industrial fluid widely used in transformers and other products until its production was banned in North America 1979.
- Dioxins: This is a byproduct of certain industrial processes that is currently regulated as a hazardous air pollutant.
Other contaminants with POP-like characteristics, but not officially listed under the Convention, are:
- Methylmercury: This is a known neurotoxin once used in fungicides until it was banned in the 1970s. This form of mercury is found in water and bioaccumulates in animals and humans.
- Brominated Flame Retardants: These are often used in fire extinguishers, upholstery and some clothing such as children’s pajamas. Two types of these retardants found to negatively affect human health have been voluntarily banned by the industry.
- Fluorinated Compounds: These are still produced throughout the world for various applications. Canada is the only country that has banned some forms of these compounds.
Mercury, lead and cadmium are of concern because of their presence in many fish and marine mammals consumed by indigenous Arctic peoples.
These are radioactive atoms that persist in soil and plants, leading to potentially high exposure levels in humans. The radioactivity can be damaging to health in a variety of ways. In the Arctic environment, many radionuclides come from human activities such as atmospheric testing of nuclear weapons or accidents such as the Chernobyl nuclear disaster in 1986. Two common radionuclides in the Arctic are Strontium-90 and Cesium-137. Radionuclides are more often found on land than in the marine food web so are a relatively lesser concern for people eating marine species.
The “Arctic Dilemma”
Persistent Organic Pollutants bioaccumulate in the food web, with the highest concentration of toxins found in top predators such as humans, polar bears, toothed whales, and seals. Many toxins accumulate in the fatty tissue of animals. They can be passed from prey to predators and from mothers to their offspring, during pregnancy and through milk.
Marine mammals with the highest concentration of toxins are also a traditional food source for coastal Alaska Native communities and provide excellent nutrition. The Arctic Monitoring and Assessment Programme, a project of the Arctic Council, refers to this as the “Arctic Dilemma.”
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