Air and water currents carry chemicals and heavy metals from all over the world to the Arctic and sub-arctic. Volatile contaminants and particles carried by air currents tend to settle as they reach the cold arctic air. Once chemicals reach the Arctic, they take a long time to break down because of the cold, lack of sunlight and lack of bacterial activity.
What many regard as pristine environments therefore contain surprisingly high levels of pollutants, despite the relative lack of polluting heavy industry in the region.
Toxic chemicals and heavy metals in arctic ecosystems work their way up through the food chain.
Studies of whale and dolphin tissues from around the world show significant levels of persistent organic pollutants (POPs) and endocrine disrupting chemicals (EDCs). In some cases, levels of these chemicals are high enough to cause damage to both reproductive and immune systems.
Researchers originally believed that toothed whales, dolphins and porpoises were at greater risk because they are higher on the food chain and therefore would be more prone to bio-accumulating toxics. Current research is showing, however, that the baleen whales are also be negatively impacted by toxics and pollutants.
Mining, metal processing, burning fossil fuels and dumping waste all increase the level of metals transported by ocean and air currents to the Arctic. They do not degrade. In fact microorganisms convert inorganic mercury, for example, into methyl mercury, a fat-soluble molecule that easily passes through cell membranes, accumulates in animals, and spreads throughout the food web.
For more on toxics in the Arctic, visit the The Arctic Monitoring and Assessment Programme (AMAP) website.
Mercury is a nerve toxin that has a major impact on the brain, particularly in growing fetus and juvenile. Mercury can also damage reproduction in mammals by interfering with sperm formation. Neurological and reproductive effects have also been seen in birds. In fish, its effects also include a decreased sense of smell, damage to gills, blindness and changes in the ability to absorb nutrients in the intestines.
WWF supports the United National Environmental Program (UNEP), which is currently conducting a global survey of mercury sources and pathways that it hopes will lead to a global convention on mercury.