 Scientists say concentrations of toxic metals have doubled in some of Colorado's high mountain streams over the last 30 years. They include iron, zinc, and copper. Rae Solomon with member station KUNC has more. With rising temperatures, some streams and rivers in the high Rocky Mountains are growing more acidic and polluted with higher concentrations of heavy metals. That hurts ecosystems, killing plants and aquatic wildlife, and it could become a problem for drinking water.