Learn how abandoned mines have been contaminating water supplies in the Rocky Mountains in this video from NOVA: Poison in the Rockies. Beginning in the 1850s, prospectors dug deep mines in the Colorado Rockies in search of precious metals. Today, more than 15,000 abandoned metal mines have filled with acidic water that carries away heavy metals like lead, cadmium, and zinc into mountain streams. In small quantities, some metals are essential to life, but in larger quantities they are toxic. Some newer mines include safeguards to make them more environmentally sound.
This video is available in both English and Spanish audio, along with corresponding closed captions.