Reference: Potapowicz, J., Szumińska, D., Szopińska, M., Polkowska, Z. The influence of global climate change on the environmental fate of anthropogenic pollution released from the permafrost. Part I. Case study of Antarctica. Sci Total Environ. 2019; 651:1534-1548. https://doi.org/10.1016/j.scitotenv.2018.09.168
The Antarctic continent has remained relatively untouched by human influence over the centuries. Or has it? Historically, the polar climate has played a major role in keeping Antarctica inaccessible and uninhabitable to humans with average temperatures ranging from -28°C (-18°F) in the summer to -58°C (-72°F) in the winter. As one might expect with these temperatures, Antarctica stays frozen throughout the year. Mountains of ice and glaciers cover the land. However, there are a few small areas that remain ice-free along the coasts of East Antarctica as well as the Antarctic Peninsula and its offshore islands. These ice-free areas have a unique feature called permafrost. Permafrost is any soil, rock or sediment held together by ice that remains below 0 °C (32°F) more than two years in a row. Ice, snow and even the dirt is frozen! Nothing decays and very little grows. It is a frozen land where time seems to stand still (literally – time doesn’t exist here. Antarctica has no time zone!).
Times are Changing
The average temperature of the earth is increasing. Retreating glaciers and the loss of sea ice are evidence that polar regions like Antarctica are not immune to this phenomenon. Over the last 50 years along the Antarctic Peninsula, the mean annual temperature has increased by 3.4°C (38 °F) and there are reports that the permafrost is diminishing. Without taking adequate steps to tackle the challenge of global warming, temperatures are certain to keep rising. What will this mean for the Antarctic’s future? What has been laying dormant for centuries in the ice and dirt? Pollutants from near and far have been accumulating for centuries on the continent; global warming will likely lead to their mobilization and potentially toxic consequences.
Up Close and Personal – Local Pollution
The continent of Antarctica has had visitors over the centuries, most in the form of explorers, scientists, and fishermen. It has even become a popular destination for cruise ships! To date, there are up to 45 year-round research stations and 30 summer field stations. The transient population fluctuates between 4000 people in the summer to 1000 in the winter. In order to survive for any amount of time in this climate, visitors need supplies. For heat, electricity and transportation, they will need to burn fossil fuels. Shipping large amounts of fuel can lead to accidental spills to the area. Garbage and sewage are produced with nowhere else to go but the surrounding environment. In an effort to preserve the Antarctic environment, the Protocol on Environmental Protection to the Antarctic Treaty was established in 1998, designating the continent as a “natural reserve, devoted to peace and science”. The Protocol held visitors accountable for their activities, thus reducing the amount and type of the waste produced on the continent. However, waste is unavoidable.
Two groups of chemicals produced by local human populations that pose a risk to the ecology of the Antarctic
are PAHs (polycyclic aromatic hydrocarbons) and heavy metals.
- Combustion of organic materials such as oil, gas, coal, wood, tobacco and even charbroiled meat create PAHs. These chemicals are potent carcinogens in both humans and wildlife.
- Heavy metals (e.g. mercury, copper, lead, cadmium) introduced through human activities (i.e. equipment, sewage) or produced by natural sources (i.e. volcanic eruptions) have the potential to mobilize with changing conditions initiated through temperature increases (e.g. soil chemistry, glacial melting, wildlife behaviour). Accumulation of heavy metals can produce extremely toxic effects on the nervous system, reproduction and development of the young.
Undercover Pollution from Distant Lands
Persistent organic pollutants (POPs) are chemicals such as pesticides, solvents, pharmaceuticals and industrial ingredients that have three defining characteristics:
- persistence in the environment
- accumulation throughout the food web
- pose a serious risk to human and wildlife health.
In short, these are some of the nastiest chemicals on earth. An infamous POP example is the pesticide DDT. DDT (dichlorodiphenyltrichloroethane) has been used to control insect populations and the diseases they transmit (e.g. malaria). It doesn’t break down quickly in the environment, so it can persist for decades in soils. It also loves fat! It will deposit in animal tissues resulting in long-lived top predators like ourselves accumulating high concentrations in fat stores and breast milk. DDT negatively impacts the immune system and hormone regulation in addition to being a probable carcinogen. Interestingly, it is still being detected in humans even though most countries banned it 30 years ago! DDT was also the root cause of declining bird populations across North America and Europe between the 1940-70s. A few other noteworthy POPs that you might have heard of are PCBs (polychlorinated biphenyls), dioxins, furans, and PFOS (perfluorooctanesulfonic acid).
Another particularly nasty quality of POPs is their ability to travel long distances far from where they originated by means of the grasshopper effect. That’s right! These chemicals hop from warmer to colder climates. On a warm day, a POP may be transformed into a vapour that is swept along with the atmospheric winds until it reaches an area where temperatures cool and it falls to the earth along with rain, snow and other particles. This cycle repeats until temperatures remain stable – like in Antarctica where it’s cold…. ALL THE TIME. This desolate land then becomes a depository for nasty chemicals that have been produced and used for the last century! Arctic research has proven that some of the highest levels of POPs have been detected in the tissues of wildlife and Inuit peoples who live far from any primary sources. A similar scenario threatens Antarctica, as POPs have been detected in penguin tissues.
The Fate of Antarctica
There is still a shroud of mystery surrounding Antarctica. Scientists do not know what lies ahead for this unique land within the context of a warmer world. However, knowledge of chemical behaviours, geological processes, and ecological responses from Arctic research provides an excellent basis for initiating monitoring programs to inform future activities. As the permafrost and ice begins to thaw, it is likely that many POPs, PAHs, and heavy metals will physically move and chemically change after remaining dormant for decades. Permafrost has potentially acted as a barrier to the downward movement of pollutants in the soil; if so, this would concentrate them near the surface making them readily available for uptake by both plants and animals. Toxic chemicals that have settled on the glaciers and ice sheets through atmospheric deposition may travel with meltwater to nearby water or soil to later become incorporated into food webs. Animals of the Antarctic, especially top predators like penguins, have a slower metabolism, unique feeding behaviours, longer life spans, and large fat stores which put them at greater risk of accumulating POPs and experiencing their toxic effects. With warmer temperatures, animal migrations may be altered both bringing new pollutants to and dispersing them from Antarctica via the food web. The warming of this giant continent will create disturbances not only locally, but globally as well. Our fates are tied.