Associated Press: Pesticides, heavy metals and other airborne contaminants are raining down on national parks across the West and Alaska, turning up at sometimes dangerously high levels in lakes, plants and fish. A sweeping, six-year federal study released Tuesday found evidence of 70 contaminants in 20 national parks and monuments – from Denali in Alaska and Glacier in Montana, to Big Bend in Texas and Yosemite in California. The findings revealed that some of the Earth’s most pristine …