Eight of the regulated gold operations with total mercury emissions of 2,564 pounds in 2009 are in Nevada and have been suspected as a source of mercury in Utah lakes and streams. Some of the highest levels of mercury's toxic form, methylmercury, have been found in the Great Salt Lake.
The lake has the nation's only consumption advisory for waterfowl because of those high mercury levels. In addition, mercury-contaminated fish have prompted consumption advisories in 16 Utah lakes and streams.
Airborne mercury lands in water, where fish and waterfowl accumulate methylmercury in their flesh. Humans who eat contaminated fish also can build up high levels, so the advisories are aimed at reducing the risk of ingesting too much mercury.
Women of childbearing age and children are at greatest risk because methylmercury damages developing brains and nervous systems sometimes even before children are born.
The new emission limits will require gold producers to cut mercury releases by more than 75 percent of 2007 levels.
And, while Kennecott's copper concentrator generated 29.4 pounds of mercury air emissions in 2009, according to the TRI, company spokeswoman Jana Kettering said Kennecott would have to read the new rules to understand how they might apply. The Salt Lake County operations produce about 400,000 troy ounces (around 13 tons) of gold a year.
EPA said more than 20 facilities that extract gold from ore will need to meet the new requirements within three years. Some reductions already have been realized thanks to monitoring and clean air equipment that already has been required by the state of Nevada.
Utah environmental consultant and activist Ivan Weber applauded the new limits, though he called them too long in coming.
"It's clear that mercury from Nevada comes here by air," Weber said, noting that the limits should have some impacts in Utah.
"It will help prevent further poisoning of the Great Salt Lake ecosystem. Whether this heals [the environmental damage already done], we don't know," he said.
Utah fish advisories
A sampling of the 16 mercury consumption advisories:
Jordanelle Reservoir • Brown trout, smallmouth bass
Weber River • Brown trout
Joe's Valley Reservoir • Splake trout
Sand Hollow Reservoir • Largemouth bass
Red Fleet Reservoir • Largemouth bass
Porcupine Reservoir • Brown trout
Steinaker Reservoir • Bluegill
Source: State health, environmental regulation agencies