Mine waste cleanup improving water quality, report says

Cleaning up historic mining waste is paying dividends for water quality in the Coeur d’Alene River Basin, according to a new report published by the U.S. Geological Survey. The report looked at two decades of water quality data for the Coeur d’Alene River and its tributaries. Since the early 1990s, concentrations of lead, cadmium and zinc have dropped by 65 percent in the South Fork of the Coeur d’Alene River near Pinehurst, Idaho. Other streams also showed improvements in water quality, though most streams continued to exceed standards for heavy metals, which are designed to protect fish and other aquatic creatures from toxic exposure. In addition, large amounts of heavy metals continue to wash down the Coeur d’Alene River and into Lake Coeur d’Alene, the report said. About 400 tons of lead, 700 tons of zinc and 5 tons of cadmium flow into the lake each year, according to data collected from 2009 through 2013. Most of the metals settle at the bottom of the lake, with some flowing out of the lake and into the Spokane River. Overall, the report is “good news for the people of the basin,” said Rick Albright, the U.S. Environmental Protection Agency’s Superfund cleanup director in Seattle. “We still have a long way to go in our cleanup efforts, but it’s nice to have scientific confirmation that we’ve made solid, measurable progress in reducing metals loads and improving area water quality.” More than 130 million tons of silver, lead and zinc ore was mined in Idaho’s Silver Valley over the past century. Before pollution controls, metal-rich tailings were dumped along flood plains and into streams, washing heavy metals downstream.