Melting Arctic ice could poison ecosystem, experts say

[cf. Polar bears ill from accumulated environmental toxins] By John Size, CTV News
18 March 2012 Arctic sea ice that’s been melting at a dramatic rate in the last few decades is releasing a chemical soup that could poison the food chain with mercury and other dangerous chemicals, a new study suggests. The NASA-led research that involved five members from the University of Manitoba will appear in an upcoming edition of the Journal of Geophysical Research. The team found that when the salt in sea ice, frigid temperatures and sunlight interact a chemical reaction releases bromine atoms into the atmosphere, which then mix with a gaseous form of mercury creating a pollutant that falls back to Earth. Over the last 30 years, the amount ice that survives the summer melt and grows again in the winter is becoming significantly smaller (12 per cent per decade), resulting in a much thinner and more salty form of ice. When the “new” ice melts, it releases a higher concentration of the chemicals into the air that create the mercury, the study found. “So we want to understand the potential human health, the potential ecosystem health implications,” Feiyue Wang of the University of Manitoba told CTV. Mercury is a toxic substance that can enter the food chain and eventually be ingested by humans through food consumption. “This is being concentrated in things like fish and it’s working it way up the food chain,” geochemist Norman Halden said in the report. “Obviously, for the people there and ourselves who are potentially eating fish, it’s an issue,” he said. As well, the “bromine explosion” caused by the change in the ice can further erode the ozone layer that protects organisms from harmful UV light. […]