Coeur d'Alene Lake and it's Metals #Superfund #Idaho #waterquality #Limnology

Added: 2026-05-05

[00:00:00]Lake Coeur d'Alene Idaho, with its crystal clear water and mountainous backdrops, is one of the most photographed lakes in American West. But beneath that beauty lies one of the largest toxic legacies in US history.

[00:00:11]Starting in the 1880s, silver mines in Idaho's Silver Valley dumped waste directly in the Coeur d'Alene River. For nearly a century, contaminated sediment flowed downstream.

[00:00:20]Today, an estimated 75 million metric tons of lake bed sediment is laden with lead, zinc, arsenic, and cadmium. Right now, those metals aren't moving. Oxygen at the sediment-water interface keeps them chemically locked in place. They are entombed beneath the water you swim in, fish in, and boat on. But if nutrients increase, the oxygen in the bottom can become depleted. This will cause chemistry shifts, and a tomb a century in the making will open. That's why the Coeur d'Alene Tribe, the state of Idaho, the EPA, and the University of Idaho, as well as local communities, have spent decades managing nutrient and metal inputs, cleaning contaminated soils in the upper watershed, and monitoring the lake's chemistry. Their efforts are working, and metal concentrations in the lake water are declining. But 75 million metric tons are still there, buried at the bottom of the lake. So the next time you see DEQ or Coeur d'Alene Tribe crews working on the water, or hear about new rules protecting the lake, remember that's not bureaucracy. That's the only thing keeping the metal tomb sealed. If you like this video and love lakes, consider joining the Washington State Lake Protection Association at walpa.org.