The U.S. Environmental Protection Agency is taking sediment samples from the bed of the Coeur d'Alene River as part of a plan to stop lead from entering Lake Coeur d'Alene.
The Spokesman-Review reports ( the $250,000 mapping project started this month and will involve hundreds of sediment samples.
The agency says the samples will help officials locate lead hot spots and where the river bottom is highly erodible.
Ed Moreen of the EPA says the information will be used to design projects targeting the worst pockets of lead.
Each year about 390 tons of lead from past mining operations washes out of the river and into Lake Coeur d'Alene. That's enough to fill about 22 dump trucks.