An estimated 352,000 pounds of lead from leftover mine pollution has washed into Lake Coeur d'Alene in northern Idaho, an official with the U.S. Geological Survey says.

Hydrologist Greg Clark said the lead washed into the lake on Jan. 18 as a result of a rain-on-snow event that caused flooding.

"We haven't seen those kinds of flows in quite a while," Clark, an associate director of the Idaho Water Science Center in Boise, told The Spokesman-Review. "We end up with a lot of metals - lead in particular - transported to the lake during those types of events."

The newspaper reports in a story published Thursday that's the weight equivalent of about 70 pickups.

The lead is left over from a century of mining. The Environmental Protection Agency last summer proposed cleaning up 300 old mine sites and contaminated groundwater areas in the region.

But Gov. C.L. "Butch" Otter, other elected officials and area residents say the $1.3 billion price is too high and the cleanup will take too long.

The agency is reviewing public comments and is expected to release a final cleanup plan later this year.

"There's so much lead in that upper basin," said Ed Moreen, a program manager for the EPA. "It's going to continue to get picked up and redistributed into Lake Coeur d'Alene until we can do something about it."

Officials said most of the lead that went into the lake in January has settled on the lake's bottom, based on low lead levels found in the Spokane River, the lake's outflow.

Glen Rothrock, of the Idaho Department of Environmental Quality, said lead levels in the lake sometimes exceed federal drinking water standards of 15 parts per billion. But he said those levels usually occur during spring runoff when the water is too cold for swimming.

During the summer, he said, the lake has lead levels of 2 to 3 parts per billion. On Jan. 18, flows heading into the lake at Harrison had about 3,500 parts per billion, Clark said.