City emphasizes reservoir water safe, mercury in fish negligible
Grand Junction drinking water source Juniata Reservoir is closed for fishing because fish in the water have tested positive for mercury contamination.
Although unsafe levels of mercury were found in small-mouth bass in the reservoir, the water is safe, according to Grand Junction City Manager Laurie Kadrich, who announced the closure during a City Council meeting last week.
The fish are not resident species of the reservoir and were illegally stocked there by an unknown person, according to a statement by the city of Grand Junction delivered Jan. 26 before the Colorado Water Quality Control Commission. The statement shows the city may remove small-mouth bass from the reservoir, possibly completing the task by this summer.
The statement adds that the city “is extremely concerned about public misinterpretations of the potential listing of its pristine terminal drinking water source reservoir as being impaired by mercury,” because the reservoir is at risk for addition to a state list of bodies of water that don’t meet water quality standards.
The reservoir was adopted as a “high priority” on the list when it received preliminary approval from the state Water Quality Control Commission on Feb. 8. Although most bodies of water on the list are included because of water contamination, Juniata Reservoir and a few other bodies were included solely for having a fish-consumption advisory, according to Steve Gunderson, director of the Colorado Department of Public Health and Environment’s water quality division.
“The levels of mercury in the water, you wouldn’t be able to detect them,” Gunderson said. “You’re talking extremely low mercury, but it accumulates in the fish.
Gunderson said state health officials are meeting with city officials about taking Juniata off the list if they can get rid of all contaminated fish or isolate the reservoir. The final list will not be adopted until March 9.
At least one fish in the reservoir had mercury in its system that met or exceeded the Department of Public Health and Environment’s limit of 0.5 parts per million, according to the department.
“Eating fish that exceed this level may cause health problems, especially for the unborn fetus and small children,” according to the reports.
Of the 20 bodies of water in Colorado that have fish-consumption advisories, half are on the Western Slope, including Purdy Mesa Lake in Mesa County, Sweitzer Lake in Delta and Rifle Gap Reservoir in Rifle.
“The standards are designed to protect what the water supply is used for,” Gunderson said. “When you have a fish-consumption advisory, you’re effecting it as a supply of fish,” not drinking water.