In Arctic Canada, "Pristine" McKenzie River Fish Species Show Huge, Abrupt Leaps In Toxin Levels

[hatrack]

Scientists studying burbot in the Mackenzie River, one of the country's most pristine rivers, have been surprised to discover that mercury, PCBs and DDT in the fish are rising rapidly, a finding they say is linked to climate change.

The increase in the amount of harmful chemicals has been huge. In the period from the mid-1990s to 2008, PCBs have risen up to six times, DDT by three times, and mercury by 1.6 times in the burbot, a delicacy in the north described as tasting like a freshwater lobster.

Contaminant levels “going up so dramatically was quite surprising,” said Gary Stern, a senior scientist with the Department of Fisheries and Oceans and lead researcher on the study, which also involved scientists from the University of Manitoba and Geological Survey of Canada. Dr. Stern said the most plausible explanation for the trend is that as temperatures in the Arctic rise due to climate change, snow and ice cover are diminishing, leading to a profusion of algae, zooplankton and other aquatic microscopic life able to absorb pollutants from water.

While this greening of the Arctic environment means there is more for wildlife to eat, it also allows harmful contaminants to enter the food chain in far greater amounts, he said. The discovery of the rising tally of harmful pollutants in fish in such a remote area of the Northwest Territories was doubly unusual for researchers because contaminant levels should have been going down, based on the declining amount of the chemicals in the general environment. Both PCBs and DDT have been banned for at least the past quarter-century, while mercury concentrations have generally been stable or falling slightly.

EDIT

http://www.theglobeandmail.com/news/national/mackenzie-rivers-fish-contaminated-with-dangerous-toxins-scientists/article1462248/

[phantom power]

1. New phrase: abrupt toxicity change

[hatrack]

2. That does have a certain ring to it, I must admit . . .

:toast:

[applegrove]

3. The arctic is basically a desert and very vuneralbe because it is.

[Nihil]

4. Might it not also be due to the increased melting?

i.e., as more of the multi-year ice has melted, the pollutants that had
been trapped in the ice for the last 25+ years are being released again?

:shrug:

[madokie]

5. Does the ice in the artic melt from the top down or bottom up

I know that when we get snow and ice here it seems to be melting from the bottom rather than from the top. I know that after a snow storm and when the sun finally comes out and shines a couple three hours I can push the snow off our deck because it will be melting down there. This last snow we had we had freezing rain first then about a foot of snow on top of that and after a couple hours of sunlight the ice was melted to the point where it wasn't sticking to the wood any longer. Just curious :hi:

[Nihil]

6. From the outside in

I understand what you mean about the bottom ice but, as various
threads here have shown, the fact that the arctic ice area has
been shrinking means that both top & bottom (polluted & pure) ice
is melting. In addition, surface meltwater will also have an
erosive aspect that will pick up recent (polluted) ice.

I'm not betting a doctoral thesis on this but it just struck me
that there is a link there ...

:hi:

[madokie]

7. I'll buy that