The U.S. Environmental Protection Agency may kill a plan to install a plastic liner along 10 miles of the polluted south fork of the Coeur d’Alene River. The liner was intended to keep clean surface water from mixing with groundwater polluted from past mining activity. Last summer, the liner drew criticism during public hearings over an expanded Superfund cleanup in the upper Coeur d’Alene Basin. Local residents worried the south fork would lose its natural look.