High levels of a naturally occurring element that can cause growth abnormalities in waterfowl have been found in water, sediment and some birds, fish and plant life near Vernal, the Department of Interior says.
Selenium leached from the soil by irrigation water has flowed into the Stewart Lake Waterfowl Management Area and the Ouray National Wildlife Refuge, Doyle Stephens, research hydrologist for the U.S. Geological Survey, said Monday.During the next two years, scientists will try to determine how the selenium is getting into the wildlife areas, "and then how it is being moved through the biological system," Stephens said.
"We've gone a little further to define where there are (selenium) problems and what the extent is," he said. "If we can pinpoint the sources, particularly in the area around Ouray, then we can take management steps to put an end to the problem."
At Stewart Lake, concentrations of selenium in water from four ground-water drains have ranged from 14 to 140 parts per billion, Stephens said.
Concentrations in water from the North Roadside Pond at Ouray were up to 93 parts per billion, he said. A portion of the refuge was briefly closed last year after discovery of several deformed embryos of coots, a duck-like, fresh water bird common in the area.
"Most water you'd sample in Utah would have no selenium in it whatsoever," Stephens said.
California is considering, but has not adopted, a level of less than 10 parts per billion as necessary to protect aquatic wildlife in areas receiving drainage, he said.
Scientists also are checking water samples at Pariette Wetlands, an experimental Bureau of Land Management wetland complex 30 miles downstream from Ouray, and Desert Lake in Emery County.
While water samples at those areas were "not entirely clean, they didn't appear to be nearly as bad as those at Stewart and Ouray," Stephens said.
He said if the source of the selenium is shallow groundwater and drainage from shallow groundwater areas, the concentrations can be reduced "by either changing the irrigation practice or removing some lands from irrigation."
Other options include chemical or biological treatment or diluting the water with another source, Stephens said.