A river basin cleanup in north Idaho is showing just how difficult it is to remove long-term pollution from Northwest waterways.
This month, the EPA is running tests on layers of muck from the bottom of the Coeur d'Alene River. It’s downstream from a federal superfund site.
As part of the test, a technician lowers a seven-foot tube into the riverbed, like a straw into a piece of bread.
When it emerges, the tube holds a sample of decades’ worth of arsenic, zinc, and especially lead. Tailings from old silver mines. Every year, the river carries hundreds of tons of lead into Lake Coeur d'Alene, where the water laps the beaches of million dollar homes.
Along this stretch of river, signs with health warnings dot the banks. EPA project manager Ed Moreen says the long-term challenge is cleaning up the bottom of the river.
“You’re working blind here," he says. "You can’t see the river bottom. What you don’t know is where the sediments are, how thick they are, what are the concentrations. All of that makes it challenging. You’re also living in an environment that’s constantly changing.”
The EPA hopes the core samples will allow them to create a kind of pollution map of the Coeur d’Alene River that points to where cleanup should start.
This story originally appeared at Northwest News Network.