Time bomb under water

Decades of mining have slopped about 72 million tonnes of lead, zinc and other metal wastes into the Coeur d'Alene lake in Idaho state in the US. Now, representatives of the Coeur d'Alene tribe and the environmentalist group, Sierra Club, have urged the Congress and the Clinton administration to fund a $1-billion restoration effort. Although the heavy metals entombed in the sediment pose no immediate threat, oxygen depletion near the bed presents a daunting cleanup challenge. Sierra Club representative Kathryn Hohmann said the situation is "a time bomb ticking on the land".