The Arctic Messenger - The Changing Arctic Environment: The Arctic Messenger - page 17

depletingsubstancesareuniformlydistributedinthestratosphere,buttheirozone-depletion
activity is much more intensive at the two poles, where very cold stratospheric temperat-
ures at the end of the polar winter are ideal for the chemical processes of ozone loss.
This time, the source of the danger was global. Wherever spray cans were used,
ozone-depleting substances were entering the atmosphere. Wherever leaking refrigerants
were used, ozone-depleting substances were entering the atmosphere. There were no point
sources, such as smokestacks or mines, and no well-known military activities.
In the early 1980s, the health risks posed by the increased exposure to UV radiation in
the Arctic were poorly understood, but enough was known to realize that such risks were
real and serious. For indigenous peoples in the Arctic, there was little they could do but
adjust their behaviour to protect against cataracts and melanoma. What of the caribou and
other wildlife that do not even have the option to reduce their exposure to increased UV
radiation by adjusting their behaviour? Once again, the activities of humanity throughout
the world were resulting in an impact focused on the two polar regions.
There was more bad news to come. Also in the 1980s, researchers studying Arctic
marine and freshwater food chains began to find high levels of a class of organic chemical
that became collectively known as persistent organic pollutants (POPs). In some Arctic
communities, particularly those that heavily depend on the marine environment for their
diet, human exposure had reached levels categorized by health authorities as indicating
“concern”. Most of the chemicals involved were pesticides and industrial products, such
as polychlorinated biphenyls (PCBs). Very few of the pesticides had ever been used in the
Arctic, but a few of the industrial chemicals were used to a small degree. By mechanisms
then incompletely understood, the chemicals were being carried to the Arctic from low and
mid-latitudes by the atmosphere and by ocean currents and were being biologically accu-
mulated in some segments of the Arctic ecosystem. Several heavy metals were also identi-
fied as contaminants to the Arctic and one of these - mercury - showed similarities to the
observations for POPs. In this case, the situation is even more complex because there are
natural as well as anthropogenic sources of mercury. It was a devastating situation for the
indigenous communities involved. Their traditional diet - the core of their social, cultur-