ISU Bengal

Issue date: 2/21/07 Section: Life

Media Credit: George Thompson The Blackfoot River

Idaho State University researchers demonstrate selenium contamination from phosphate mining could lead to noticeably fewer trout in southeast Idaho. Rob Van Kirk and Sheryl Hill have developed a population model that demonstrates that two of the largest Yellowstone cutthroat trout populations are threatened by the contamination. The computer simulation model is one of the first to incorporate laboratory toxicology results with life cycle parameters to assess population-level effects of selenium on trout in the Blackfoot and Salt River watersheds in southeastern Idaho and western Wyoming.

"Our model shows that selenium concentrations in the Blackfoot and Salt River watersheds are high enough to cause observable declines in cutthroat trout populations in some streams," said Van Kirk, who holds a Ph.D. in mathematics and specializes in mathematical models of aquatic systems. "Selenium contamination has essentially eliminated trout form East Mill Creek in the Blackfoot drainage, and other populations we have not monitored many have already declined." Van Kirk said systematic field study is needed to determine what is actually happening in southeast Idaho streams.

Selenium is a naturally occurring element that can be toxic at higher concentrations. When phosphate is mined, selenium is part of the waste rock and frequently leaches into soil and water. Selenium is particularly hazardous because its effects are not instantaneously obvious. The contamination is progressively taken up by plants and insects, which in turn are eaten by fish and other animals. The highest concentrations are found in fish and other organisms at the top of the food chain. In the mid-1980's, selenium contamination at the Kesterson National Wildlife Refuge in California poisoned thousands of birds and fish. The refuge has yet to be fully restored.

Researchers, scientists, wildlife managers, local anglers, and hunters are becoming increasingly concerned about the effects of selenium pollution on trout and other wildlife in the Blackfoot and Salt River watersheds in southeastern Idaho and southwestern Wyoming. Concern about selenium contamination has prompted the Idaho Department of Health and Welfare to post advisories warning parents to limit the number of fish children from East Mill Creek consume, and the Idaho Department of Health and Welfare to caution hunters against eating too much elk liver.

Continued...

Page 1 of 2 next >

Article Tools