SALT LAKE CITY (AP) -- Scientists may finally be closing in on the source of mercury fouling Utah's Great Salt Lake.
The Environmental Protection Agency is funding an effort by a University of Utah researcher and others to scan the air over the lake in search of mercury and any hints about where it's coming from.
Machinery went up near the lake's shore last summer. The latest round of EPA money this spring will pay for data analysis.
Several years ago, U.S. Geological Survey tests showed the lake had some of the highest mercury readings ever recorded in a United States water body.
High levels have also been found in some ducks at the lake, a popular rest-stop for millions of migrating birds each year. In 2005, Utah became the first state to issue warnings about eating certain kinds of waterfowl because of mercury.
Despite that warning -- and years of study about how mercury is affecting birds, brine shrimp and other organisms -- a vexing question has gone unanswered.
"Where is it coming from? We don't know," said Cheryl Heying, director of Utah's Division of Air Quality.
Suspicion falls on a number of sources, including coal-fired power plants across the West, gold mines in Nevada, volcanoes in Indonesia, development in China and India and local leftovers from nearby industries.
Kevin Perry, an assistant professor of atmospheric sciences at the University of Utah, said the air monitor that went up last July near Antelope Island State Park should pick up some bits of airborne mercury that are traceable to a source.
The monitor is expected to be up for at least four years.
Part of the latest round of EPA money will also pay for researchers to analyze nearby snow and mountain lakes to find out whether they're holding mercury that eventually finds its way into the 1,700-square-mile Great Salt Lake.
Study results published last year showed that about 80 percent of the mercury that gets to the lake is being deposited from the air, said Dave Naftz, a USGS researcher who has studied the Great Salt Lake for years.
"That's the main thing we have to work on," Naftz said.
Perhaps as important, though, is understanding why peculiar conditions at the lake are so ripe for converting mercury into the more harmful form of methylmercury, a process that's still not fully understood.
In some cases, the mercury gets into the brine layer on the lake bottom and makes its way up the food chain to the brine shrimp and then to the birds that eat them.
Wildlife officials are particularly concerned about the birds ingesting the contaminant. Mercury can cause neurological damage in birds and affect their ability to fight off diseases.
Preliminary results from a 2008 study of cinnamon teal ducks that spend part of the year in the lake's wetlands found no alarming trends but a few individual samples where mercury levels were high.
"But it's only one year of data so it doesn't really speak to the variability in conditions that could lead to higher or lower exposure," said Chris Cline, a U.S. Fish and Wildlife Service biologist conducting the research.
(Copyright 2010 by The Associated Press. All Rights Reserved.)