By: Arin
When envisioning the high Arctic, people tend to conjure pristine wild landscapes and unique and beautiful ecosystems; untouched by the modern world, a remnant of a simpler time. Unfortunately, while the Arctic is certainly characterized by unique ecosystems and a greatly reduced human presence compared to lower latitudes, it can have stores of contaminants higher than most industrialized cities. How is this possible?
Background: Pollutants in the Arctic
In the 1940s humans started making persistent organic pollutants (POPs), including pesticides like DDT and industrial chemicals like PCB. The first sign that these were dangerous occurred decades later in the form of dead birds washing onto beaches in Sweden. Then, in 1962 Rachel Carson published Silent Spring, introducing the general public to the effects of these contaminants on wildlife. This kicked off a time of increased environmental awareness, study, and partial bans, before finally in 2004 the Stockholm Convention outlawed 12 of the most destructive POPs.
The production of these chemicals was banned, and they are now known as "legacy POPs". However, new or "emerging" POP production continued. These new POPs are in almost everything: flame retardants for clothes, furniture, and other products, gortex and water proofing, and food packages. They get emitted into the atmosphere, thrown and expelled into the ocean in industrialized countries, and leached out through garbage and plastic in the water and the soil. Eventually they find their way to the Arctic.
Part of the point of POPs is that they are persistent, meaning they take a long time to break down. This is convenient because we usually don't want our stuff degrading and turning into mulch. But since they stick around for so long and are so small, they can travel great distances through the global currents of the atmosphere and the ocean, as well as hitch rides with migratory animals and micro-plastics heading for the Arctic. Usually produced in warmer areas, POPs are vaporized and enter the atmosphere, following the winds to the north where the cold temperatures cause them to condense and fall to earth. There, they enter the food chain.
A glaucous gull stealing a barnacle goose egg in Svalbard before accidentally kicking it off the cliff. It's role as a predator leaves this species to feel the brunt of negative effects from POPs
Pollutants in the Arctic Food Web
Once in the arctic waters, POPs contaminate marine microorganisms like zooplankton. Fish then eat these plankton, those fish are eaten by more fish, which are eaten by seabirds, then eaten by predatory birds, then foxes, then polar bears. As each animal consumes another they transfer their concentration of contaminants, which strengthen with each trophic level.
So while the concentration of POPs is relatively low in the zooplankton, it becomes very high in top predators like seals, whales, predatory birds, and polar bears. Because fat is a crucial resource for survival in the arctic, and because POPs accumulate in fat, they are stored in the animal for long periods of time, and concentrate more with each new exposure. These animals now have very high POP concentrations in their blood, fat, muscle, and liver tissue. Even POPs whose production was banned decades ago (like DDT) are only now condensing in the Arctic food webs and showing up in animal tissue. These chemicals are that long lived, and that persistent.
My graduate research looked at POPs in Atlantic Puffins in Svalbard, Norway. While they had relatively low levels of emerging POPs and pesticides like DDT in their blood, it's incredible to think that a chemical banned in the 1970s in the West is showing up at all in the blood of high Arctic seabirds in 2018.
Effects of Pollutants
What effects do POPs actually have on organisms? Different contaminants have different effects for different species, depending on age, sex, migration routes, diet, exposure, etc. Some effects found in the high Arctic:
Disruption of hormone systems, causing birds to abandon nests, lay thin-shelled eggs, or otherwise negatively affect reproduction.
Physiological stress, leaving birds vulnerable to disease and parasites.
These sound like small things, and in fact it is rare that an animal outright dies from contamination. The effects are more insidious than that. They drain energy reserves slowly and stress and disrupt crucial steps in a short breeding season. Over long periods of time these small effects accumulate into decreasing populations that affect other species as prey supplies dwindle.
female birds can deposit some of their pollutants to their offspring via egg laying, contaminating egg shells and chicks like this blue thick-billed murre egg, puffin egg, and barnacle goose nest
Effects for Humans
Now if these contaminants concentrate with each trophic level, who then is at the top? As always, humans. In the Arctic, top predators have the highest levels of POPs, especially for those old legacy POPs like DDT. But if you look at all POPs at all trophic levels, contamination is higher closer to pollution sources and human activity.
This means we are always exposed to background levels through our diet, the air we breathe, and general exposure in our daily lives. At this point exposure to these pollutants is unavoidable.
Given human's tendency to eat fish and whale, humans can receive a high concentration of contaminants. Many indigenous people rely on subsistence hunting of marine mammals and fish to both preserve cultural traditions and to reliably feed themselves in a remote environment. These days though, eating whale blubber gives you a high dose of the POPs stored in the fat tissue, and this is causing health problems in many indigenous communities. POP exposure for humans can increase cancer risk and cause disruption to the immune, endocrine, and reproductive systems.
The Progress Being Made and New Challenges
There is progress being made though. In the 1970's seabirds were found convulsing from contamination in Norway, while dead seals and birds washed up on beaches. Following the global bans on dangerous POPs, levels of the legacy contaminants like DDT have decreased, and continue to go down.
Those monitoring human exposure have also reported steadily decreasing levels since 1980 for most of the countries studied. Additionally, there has been international cooperation when it comes to controlling POP exposure and these efforts have positive effects, which show promise for the future.
However, melting sea ice and permafrost from climate change have been releasing stores of legacy POPs into the environment. Additionally, old stores of POPs from abandoned military sites, working smelters, shipyards, and river runoff continue to release pollutants into ecosystems.
Many new POPs are also unregulated and unstudied, while others can take so long to accumulate that negative effects can be difficult to prove (although they may become problems in the future).
So while more extensive and long term research is needed to properly understand effects, especially of new pollutants, diplomatic means have made many positive strides. The Arctic currently serves to demonstrate the long term and long range reach of global pollution, but it also has shown that efforts to protect the wild can work if we follow the science and pursue solutions together.
Comments