"This shows the problem is ubiquitous," said Cheryl Heying, a member of the Statewide Mercury Work Group and a state air-quality official. "And there are hot spots."
John Whitehead, assistant director of the Utah Division of Water Quality, said more than a dozen areas around the state - many of them favorites among fishermen, like Jordanelle Reservoir, the Weber River, Joes Valley Reservoir and Panguitch Lake - have been identified as mercury hot spots.
"This is one of our major concerns," said Whitehead.
Other popular fishing waters where at least some fish were above the federal mercury limit (when averaged, they fell below) include: Strawberry Reservoir, Deer Creek Reservoir, Bear Lake and Scofield Reservoir.
The Utah Health Department is going over the results of mercury tests on nearly 821 fish taken from 139 locations around the state. On average, they found that 12 percent of the fish sampled contained mercury above levels considered safe for unlimited consumption by the U.S. Environmental Protection Agency.
Whitehead said it will be about a month before the state Health Department finishes reviewing the data and decides what sort of advisories are in order, if any.
"If you look at the data set, it's pretty clear some of these sites have a pretty clear conclusion and some are questionable and need further sampling and analysis," he said.
The advisories are intended to protect people from ingesting too much mercury in its toxic form, methylmercury, which is a neurotoxin. The advisories usually target women of childbearing age and young children, who, if exposed to too much mercury, may suffer impaired brain function that can result in difficulty thinking, talking and/or remembering.
Methylmercury builds up in the food chain and eating contaminated meat is thought to be the most likely way for people to be affected.
Utah officials already have issued consumption advisories for three fish - channel catfish from the Green River in Desolation Canyon; largemouth bass from Gunlock Reservoir in Washington County; and brown trout from Mill Creek in Grand County - and three Great Salt Lake ducks, the common goldeneye, northern shoveler and cinnamon teal.
One question making it difficult for the state to decide on more advisories is that in some sites there have been too few fish sampled to determine scientific certainty that they contain mercury above levels considered safe.
Walt Donaldson, chief of aquatics for the Utah Division of Wildlife Resources, says he would like to see a larger sample size from each of the sites.
"A sample size of three to five fish is not enough to indicate an area of concern," he said. "We would like to [look] at 30 or more fish for a broad spectrum. That would allow us to look at young fish and old fish and develop a solid average."
Ed Kent, chairman of the Utah Anglers Coalition, said he was not surprised with the announcement of the new mercury hot spots.
"This is a known persistent problem in other parts of the country. Even though it is still in its infancy here in Utah, as far as the discovery of it, I'm not sure it will have an impact on the fishing industry," Kent said. "We just need to be sure to educate the public and let them know the risks."
Collecting and processing samples costs about $50 apiece with a new mercury analyzer the state bought about a year ago. And, with no additional funding to address this relatively new issue, the agencies have been limited in the number of samples they process.
Last year, the EPA turned down a state request for about $95,000 to help understand mercury in the Great Salt Lake, where methylmercury levels are some of the highest ever measured in the United States. Gov. Jon Huntsman Jr. has requested $213,600 in his 2008 budget proposal specifically to deal with the mercury problem, including tracking down the sources that might be responsible for the contamination.