Mercury

The Hells Canyon Complex (HCC) is the largest privately owned hydroelectric power complex in the United States. Upstream are millions of acres of irrigated agricultural lands and Idaho’s largest metropolitan area clustered around the state capital Boise. Downstream lie confluences with the Salmon and Clearwater Rivers, critical habitat for threatened bull trout and fall chinook salmon. Elevated...

Mining of stibnite (antimony sulfide), tungsten, gold, silver, and mercury near the town of Stibnite in central Idaho has left a legacy of trace element contamination in the East Fork of the South Fork of the Salmon River (EFSFSR) and its tributaries. Concentrations of arsenic, antimony, and mercury frequently exceed human health criteria and may impact threatened or endangered salmonid species...