Last fall, Cascade Pole installed a new kind of discharge pipe, called a diffuser, which was engineered to help dilute the pollutants in the river water. The idea is to minimize the environmental impact, said Steve Eberl, an Ecology supervisor. It also means a portion of the river would be designated a pollution mixing zone. Within the zone, river water won't meet quality requirements. Tribal fishermen often set nets upstream from the pipe.
Adult fish pass through the area quickly.
A bigger concern is juvenile salmon, which may spend weeks or a month near the river's mouth, Sullivan said. Cascade officials haven't ignored the fish. They hired a biologist to evaluate how the new pipe would affect salmon. He found no adverse impacts, Lonning said. Still, Dinicola and others disapprove of mixing zones for such potent, long-lived toxic chemicals as pentachlorophenol, also known as penta, which they say is the most dangerous poison applied at Cascade Pole.