Be careful fishing out on Lake Granby, just west of Rocky Mountain National Park: Some fish contain health-harming mercury, writes the Vail Daily. And unfortunately, the problem isn't isolated to that lake. About 20 percent of Colorado's lakes and reservoirs contain tainted fish, according to The Denver Post, citing the analysis of state public health officials, who are also perplexed: The heavy metal pollutant isn't found in all lakes or species, according to Nicole Vieira, a Division of Wildlife aquatic toxicologist. "If we can figure out what is at work, we might be able to manage the fish stocks to reduce mercury," she says. To lower contamination levels, the state wants power plants that emit mercury to cut their emissions of the pollutant by 90 percent by 2018. Fish aren't the only animals affected by man-made pollution, writesÂ The Associated Press. The American pika--a furry little creature that hangs out on mountain slopes in several states, including Colorado--is being threatened by climate warming.