What is Mercury/Methylmercury and what are its properties and potential harmful effects on the arctic?
Mercury (Hg) is a toxic heavy metal that changes into various chemical forms through geochemical processes. It is an element that occurs naturally in the environment but with industrialization, humans have altered itc cycle by adding more mercury in the water, air and soil. The gaseous form of mercury is quite stable, allowing it to be transported from industrialized countries that combust a lot of fossil fuels (such as China, the USA and India). As a result, the mercury is transported by prevailing winds into the arctic.
Methylmercury (MeHg) is a form of mercury that is especially toxic to humans because it can easily absorb within the human body. Methylmercury is a result of the biochemical abiotic processes that occur within the air, snow, sediment, and water. It is hamrful to humans because it bio-accumulates in the food web which is of cause of alarm to Inuit. Traditional country foods can consist of animals that are high on the trophic levels (such as polar bears, whales and seals). This can expose Inuit to higher levels of methylmercury.
Climate change is of special concern in terms of methylmercury for a number of reasons. The first is that with increasing temperatures, the melting permafrost, and increased precipitation is expected to increase the amount of Hg and dissolved organic matter into watersheds. This will result in the methylation that occurs in sediments. The resulting MeHg will be transported through rivers into the marine ecosystem where it will enter the marine food web. As well, there will be longer periods of ice-free seasons and permafrost melt which will prolong the season inw hich methylation can occur. Climate change can also affect the fiet of animals within the arctic food web. The dietary shift will expose animals to different foods resulting in changes of their MeHg concentration. Lastly, climate change is projected to increase the productivity of marine ecosystems which would allow lower trophic organisms (plankton) to absorb more MeHg than usual which could lead to a higher bio-accumulation in the higher trophic levels (polar bears).
Contact: Joshua Komangapik JKomangapik@GOV.NU.CA