Mercury threat not identified in mining story.

Posted by Roxanne Karimi at Oct 07, 2011 06:00 AM |

An Associated Press article describes the potential threat to nearby salmon fisheries from a proposed open-pit gold and copper mine in Alaska. The article mentions how the Pebble Mine could "destroy or degrade" salmon habitat.

The habitat degradation may likely include sedimentation below the mine in the waterways that are prime salmon habitat. Thriving salmon fisheries – mostly sockeye salmon – exist in the remote region. The increased soil, debris and other wastes released by a mine may harm the fragile streams and lakes where fish live and spawn.

However, the article omits another potential  threat – mercury pollution. Mercury could enter the waterways if the mines employ the common practice of using mercury to extract gold. The mercury could pass into the fish, which would offer a conduit into people and wildlife. Mercury is a potent neurotoxin that is especially dangerous to the developing brains of fetuses and children.

The article does not mention how the gold and other metals would be extracted. Indeed, no one yet knows as the companies have not filed or released development plans for the operation. If mercury is used, the threat of mercury pollution affecting these valuable fish can occur even if habitat quality is unaffected by the mine. Other chemical wastes may be involved, too.

Updated 10/11/11: Since mining practices can have such a range of environmental impacts, many of which devastate aquatic ecosystems, the public needs more information on the specific mining practices to be used, in order to understand the risks of the mine. Even if the salmon fishery is maintained, the salmon are likely to be exposed to a range of pollutants that will enter the food chain.

When reporters write about plans to develop mines, they should remember that environmental pollutants, not just habitat damage, could pose a threat.


Correction 10/10/11: Gold mined in the United States is not processed with mercury. Cyanide is used in most cases. However, mercury is often found in the same ore as gold, and it can be released when the ore is heated to extract the gold during processing. The U.S. Environmental Protection Agency regulates how companies contain this source of mercury.


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