Mercury is contaminating the Grand Canyon's fish and wildlife

August 26, 2015, 1:45 p.m.
Horseshoe Bend is a famous and favorite spot in the Grand Canyon, a place increasingly under threat from development and pollution.
Photo: Francesco R. Iacomino/Shutterstock

Visitors to the Grand Canyon enjoy a sweeping vista of unparalleled beauty, but researchers focusing more closely have found something far less attractive. According to a new report by U.S. Geological Survey scientists, there is a worrying amount of mercury making its way into the food web of wildlife in the canyon.

Discovery News writes, "Researchers collected data from six sites along along the Colorado River, which winds through the Canyon. They found that the mercury and selenium concentrations in minnows, invertebrates and fish exceeded dietary toxicity thresholds set for fish and fish-eating wildlife. The data also revealed that the average mercury concentrations in many of the fish studied would make them unsafe for humans to eat as well."

The scientists note that "the findings of the present study add to a growing body of evidence showing that remote ecosystems are vulnerable to long-range transport and subsequent bioaccumulation of contaminants."

However, managing such pollutants getting into the park's ecosystem is not easy, because the source is usually far beyond the park's boundaries. Mercury pollution comes from coal-burning electrical plants, steel production, incinerators and cement plants as well as other human-caused sources. As for how it gets into the Grand Canyon from these distant places, the scientists believe that much of it is being transported by algae from Lake Powell.

This study underscores the importance of widespread environmental responsibility, because our national parks don't have impermeable boundaries. What we do outside of the parks affects the conditions within the parks.

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Jaymi Heimbuch is a writer and photographer at Mother Nature Network. Follow her on Twitter, Google+ and Facebook.