SALT LAKE CITY — Every state has so much mercury in its water that it’s dangerous to eat many of the fish caught in its lakes and streams — and Utah’s Great Salt Lake is no exception.
There are no fish in the lake, but mercury contamination travels through sediment and microscopic organisms into brine flies and brine shrimp. Ducks that live on the lake and eat those shrimp and flies end up being dangerous to eat.
All this and more was discussed Wednesday at this year’s Great Salt Lake Issues Forum, held every two years by Friends of Great Salt Lake, a nonprofit advocacy agency.
The forum brings together national experts to discuss the critical role Great Salt Lake plays in Utah’s economy, climate and culture.
This year’s forum, held at the Fort Douglas Officers Club, included a special session Wednesday just to discuss mercury contamination. The forum continues through Friday.
Mercury from gold processing, cement manufacturing and power plant emissions is a major polluter of the whole food chain contained in Great Salt Lake, from brine flies to ducks.
Once in the food chain, mercury can cause health problems, including brain development issues in children. Mercury contamination in Great Salt Lake potentially impacts duck hunting and brine shrimp harvesting, both major industries.
It can also affect the ability of birds to breed and hatch their eggs, a critical issue, as Great Salt Lake is a major migratory flyway with millions of birds passing through every year.
The forum received a major message of hope from keynote speaker David P. Krabbenhoft, of the U.S. Geological Survey.
He said regulations approved last year should cut mercury emissions nationwide by 50 to 70 percent. That reduction, which must take place within three years, will make the United States a world leader in mercury emissions control, he said.
Even better, Krabbenhoft said, studies show that once emissions are cut, the amount of mercury in the environment will also drop fairly rapidly.
The USGS found this out by the straightforward method of adding mercury isotopes — radioactive mercury that can be easily traced — to a small lake ecosystem in Canada and measuring what happened to it.
Isotopes were added for seven years and constantly monitored, Krabbenhoft said. Levels of isotopes spiked around the time they were added, but then dropped quickly when they stopped. Normally occurring mercury, meanwhile, stayed about the same.
After seven years, researchers quit adding isotopes, and levels dropped back quickly to natural levels.
“This is really the best evidence that, on an ecological system scale, reductions in emissions that result in reductions in loads will have really fast regression,” Krabbenhoft said.
The problem is that mercury is a worldwide issue.
China and India are still major emitters, and much of the mercury they produce ends up in the Pacific Ocean, where mercury levels have risen 30 percent in the last 20 years and will go up another 50 percent by 2030.
Research on mercury in Great Salt Lake is centered around wildlife, everything from brine shrimp to ducks.
Jodi Gardberg, who works for the Utah Division of Water Quality, said an advisory in 2005 restricted consumption of three types of duck: Northern shovelers, common goldeneyes and cinnamon teal.
The advisory said healthy adults shouldn’t eat more than one 8-ounce serving of those three per month, and pregnant women and children shouldn’t eat them at all.
Her division did a study in 2008 to measure levels of mercury contamination in various parts of Great Salt Lake. It found levels of mercury were high at lower lake levels but stayed low near the water’s surface.
As for human health concerns, Gardberg said the tests her division did on birds found much lower levels than those that caused the 2005 restrictions, but said additional study needs to be done to figure out why the levels differ.
One problem is that birds fly around, she said, so it’s hard to tell where the birds get contaminated.
To learn more
The Utah Department of Environmental Quality maintains a website, www.mercury.utah.gov, with full information on mercury pollution in Utah, including health advisories, recent research and cleanup information.