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Copper - one more reason Pebble Mine threatens Bristol Bay's salmon

Sylvia Fallon

Posted April 14, 2010

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There are many reasons that Pebble Mine, the proposed copper and gold mine in southwest Alaska’s Bristol Bay area, would threaten one of the most productive salmon fisheries in the world.  As we have been highlighting here, operation of the mine could cause the partial or complete dewatering of miles of freshwater streams; construction would include the development of roads that could cross numerous known salmon streams; waste products would be stored in large tailing ponds that could leak toxic elements into the surface and groundwater.  These types of impacts on the salmon fisheries are perhaps the most obvious.

One of the greatest threats to the fish, however, might not be the byproducts of the mine and its construction, but the target of the mining operation itself: copper.

Copper is naturally occurring in the environment, but if copper levels increase even slightly above naturally occurring levels, it can be toxic to fish and other aquatic life.  Certain activities such as hard rock mining can lead to elevated levels of copper in surrounding waterways which is why there are established water quality thresholds for copper (and other metals).  Research shows, however, that copper can affect salmon and their food chain even at levels below these established thresholds. 

For example, increases in copper – even small increases that comply with federal regulations -- can interfere with salmon’s ability to smell and sense vibrations which has been shown to put salmon at a greater risk of predation.  A lack of smell or changes in the water chemistry of an area also can inhibit salmon’s ability to migrate and accurately find their natal habitat.  In addition, increases in copper can kill algae, zooplankton and aquatic insects all of which provide a major food source for salmon.  Finally, increases in copper can kill freshwater mussels which are a food source for humpback whitefish – a subsistence fish in the Kvichak watershed.  Humpback whitefish, in turn, are a food source for salmon.

The effect that copper will have in any given waterway is influenced by a number of variables and is therefore hard to predict.  However, this research indicates that even if Pebble mine were able to strictly comply with the established water quality standards, salmon in the area could still suffer detrimental effects.  While additional research will help us better understand site specific consequences of increased copper under different water conditions, the available data already clearly indicate that building a massive copper mine in the heart of one of the most productive salmon fisheries in the world is simply not worth the risk.

Please take a minute to sign our petition opposing Pebble Mine.  We will deliver the petition to the British mining giant Anglo-American, at its annual shareholder meeting on Earth Day.

Bristol Bay Sockeye Salmon

Image: Bristol Bay Sockeye Salmon shared by toddraden via Flickr.

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the TruthApr 14 2010 07:25 PM

Perhaps it would be wise for Ms. Fallon to review Alaska's mine permitting requirements before making outrageous assertions like "operation of the mine could cause the partial or complete dewatering of miles of freshwater streams" - something that would never be allowed under the current regulatory regime. Second, I find it troubling that the staff scientist would fail to mention that salmon throughout Alaska are subject to a huge natural variation of dissolved copper levels, yet they continue to thrive - even at levels far beyond what's present at Pebble. This flies in the face of this story's very premise. Have you ever heard of the Copper River (or Copper River Reds)?

Thor-ZoneApr 14 2010 10:43 PM

If this is the type of science NRDC practices, you should be ashamed. The facts on the ground here are far different than what Ms. Fallon professes in this article.

The copper issue as described in this article is farfetched at best. There was a recent study funded by anti Pebble groups which claims that changes as little as two parts per billion of copper in the water will cause the salmon to lose their way. That doesn’t even pass the most basic test of reality.

According to the US Fish and Wildlife the levels of copper that occurs naturally in the Copper River are up to about 290 parts per billion. The amount of copper changes during the course of the year with low readings of around 10 parts per billion during freeze-up and a high in late summer of about 280 to 290 parts per billion copper. The recent anti Pebble study claims that as little as 2 parts per billion will cause the salmon to lose their way. It doesn’t work that way across Alaska where salmon have been swimming in these rivers for thousands of years.

For those who are not familiar with the Copper River, it has one of the most prolific and highest quality runs of salmon in the world. People from all over the world pay very high prices to get Copper River Salmon into their kitchens and restaurants.

Environmental activists love to use all sorts of flawed studies like the recent salmon study to make it seem that any trace of man in the woods will destroy all life out there. It simply does not match the facts on the ground.

Sage ThomasApr 15 2010 12:10 PM

The pollution that would result is real, and remember- everything is connected. Remember the copper levels that the fish deal with are of a natural cycle, extraction and pollution is not natural- perhaps the unnatural (as human processes unfortunatly do not mimic that of nature) copper will produce more of a reaction in the salmon

Sylvia FallonApr 15 2010 04:07 PM

Thanks for your comments. The last commenter is correct in that there is a difference between natural and unnatural levels of copper. Natural levels of copper are generally low and sampling in the Pebble mine area indicates that the natural copper levels there are low.

Furthermore, as I mentioned in my blog, the effect that copper has on salmon and other aquatic organisms varies depending on a number of factors and therefore copper can have different effects in different areas. However, research conducted primarily by the National Oceanic and Atmospheric Administration (a federal agency) clearly shows that under certain conditions even small amounts of copper can be toxic enough to disrupt behaviors that are critical to salmon survival. (For more information:
Additionally, copper can diminish salmon’s food resources. While further research will provide more information on site specific effects of copper, we believe there is sufficient evidence to suggest that the possibility for elevated copper levels from a large scale copper mine would pose too great of a risk to the economically and ecologically rich, renewable resource of salmon in this area.

Finally, regarding water use and what is allowed under state permitting , it is worth pointing out that Pebble Partnership was recently fined for 45 violations over the past 3 years for unauthorized water use. Regardless, the point is that pumping hundreds of thousands of gallons of water can significantly affect waterflow and other conditions of surrounding waterways where salmon occur.

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