In Washington state, excess copper in the environment that has been found to be harmful to salmon has been attributed to urbanization. Specifically, copper used in automotive brakes. When a driver hits the brakes, friction releases copper shavings onto the road that are eventually washed into the surrounding watershed. In response, Washington state passed a law to phase out the use of copper in brake pads.
Urbanization and the increased traffic it brings could be at least part of the reason for increased levels of copper found in conjunction with frog deformations in Alaska. Only two of the five refuges monitored in the state showed frog abnormalities, and they were the only two that are road accessible. Tetlin, along the Alaska-Canada border, is accessible by the Alaska Highway. And Kenai has even more urban development and roads.
But metals occur naturally in the environment, as well, so it can be challenging to tell if elevated levels of copper are from some kind of human-caused development or simply geology. The Kenai refuge, for instance, also has an abundance of naturally occurring arsenic in the watershed.
But limb abnormalities have been found in Kenai frogs both near roads and far from them. "There are just all of these incredibly complex interactions that are going on. It leaves me scratching my head, I can assure you," said Meg Perdue, a Fish and Wildlife Service biologist.
Read more at The Redoubt Reporter.
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