Lecture 13: Organic pollutants in the Arctic Flashcards
Persistent organic pollutants (POPs)
are toxic chemicals that adversely human health and the environment around the world. POPs are transported by wind, water, and food cycles making them transient across borders, continents, and ecosystems. Because they are resistant to environmental degradation, they persist for long periods of time in the environment and can accumulate and pass through the food chain. (see figure)
POPs regulation
POPs are regulated worldwide by the Stockholm Convention (2001) and the Aarhus Protocol (1998). These international treaties are implemented in the European Union by the POPs Regulation.
POPs regulation aims to protect human health & the environment with specific control measures that:
*prohibit or severely restrict the production, placing on the market and use of POPs;
*minimise the environmental release of POPs that are formed as industrial by-products;
*make sure that stockpiles of restricted POPs are safely managed and
*ensure the environmentally sound disposal of waste consisting of, or contaminated by, POPs.
Chemical substances that have been identified as POPs include:
*pesticides (such as DDT);
*industrial chemicals (such as polychlorinated biphenyls, which were widely used in electrical equipment; fire retardants);
or
*unintentional by-products formed during industrial processes, degradation or combustion (such as dioxins and furans).
Brief history of POPs
In the 1970s and 1980s, high levels of POPs were unexpectedly found in the Arctic, far away from the main sources of these pollutants.
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.”
Biomagnification occurs in the arctic see figure below
bioaccumulation in tissue occurs at higher trophic levels e.g. in higher predators which are common in indigenous foods e.g. toothed whales and polar bear
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.
(see figures)
^ melting sea ice, shipping collisions/shipwrecks release major pollution
see also: POPs guide PDF on ultra – article used by policy makers, straightforward read with useful content
POP 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.
^ 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.
Wildlife impacts of POPs
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 (and people consuming them) 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.
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.
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.
Associations between climate indicators and contaminant trends:
See figure
lipophilic POPs = fat soluble – these POPs bioaccumulate in tissue with toxic effects
^particularly higher up the food chain e.g. in polar bears (see figures from letcher 2018)
Other species that have been victims of POPs: peregrine falcons and other birds of prey
Nesting along the Yukon River, their exposure to DDT (insecticide) 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.
(DDT accumulated in predatory birds who fed on birds consuming insects that had consumed DDT)
See: Ambrose et al. (2016) Recovery of American peregrine falcons along the upper Yukon River, Alaska. The Journal of Wildlife Management 80(4): 609-620.
Health threats to Northern humans (consuming traditional diet):
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.
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.
rising climates are increasing atmospheric POPs due to ice-melt releasing ‘legacy’ POP deposits from 1980’s (see figure)
Recommendations Based on the findings of this AMAP assessment:
The AMAP Working Group recommends the following steps:
Incorporate knowledge of climate change effects on contaminants into regulatory processes addressing POPs
Reaffirm calls for action on POPs an CEACs
Extend the knowledge base on climate change effects on contaminants
Extending the knowledge base on climate change effects on contaminants:
Expand studies considering the impact of climate change and related ecosystem changes on POPs and CEACs, including the role of extreme weather events on long-range transport and releases from secondary and local contaminant sources. These studies should be expanded in both scope and geographical coverage, to improve the knowledge base and understanding of key processes.
Extend long-term contaminant monitoring programmes in geographic and analytical scope, including broadening analyses to include CEACs, and collection of ancillary biological, ecological, and climate/meteorological data. The complex interactions between climate change
Promote increased co-production of knowledge by encouraging community-based studies and promoting capacity building in Arctic communities and scientific research programs. The use of Indigenous Knowledge and local knowledge for interpreting POPs trends and their links with climate change, would complement scientific studies and facilitate a better understanding of processes that affect POP and CEAC transport and fate under changing climate conditions and ecosystems.
Further develop temporal trend analytical methods and approaches tobetter incorporate and investigate relationships with climate-related parameters and apply these to retrospectively re-analyze trends in existing time-series, thus building on the knowledge gained from the limited number of studies where such work has been done so far.
Encourage interdisciplinary research that reflects the complexity of physical, chemical and biological processes and the rapid developments both with regard to climate change and chemical contamination. This integrative approach would benefit from collaboration among disciplines, government, universities, and Indigenous peoples and local communities.
Key points
POPs, both historical and contemporary are a major biological threat globally,
but especially so in the Arctic
Arctic conditions exacerbate the POPs problems
Biomagnification up the food chain is a serious problem
The whole range of climate impacts interact with POPs, further exacerbating POPs problems
Despite reductions in POPs production (since late 1990s and early 2000s), certain POPs are
on the increase again in the Arctic – re volatilization to blame?
