Numerous airborne contaminants, including heavy metals and pesticides have been detected at measurable levels in ecosystems at 20 western U.S. and Alaska national parks from the Arctic to the Mexican border. That’s the upshot of a six-year federal study funded primarily by the National Park Service (NPS). Some 70 contaminants were found at detectable levels in snow, water, vegetation, lake sediment and fish, according to the study. The three contaminants of most concern for human and wildlife health were mercury, and the insecticides dieldrin and DDT. The eight core national park areas studied were: Glacier, Mount Rainier, Olympic, Rocky Mountain, Sequoia and Kings Canyon, Denali, Gates of the Arctic, and Noatak. Something to think about as we admire the views on our next visit to one of these national parks.