Dust study provides clues about air pollution coming from dry Great Salt Lake

Wednesday , March 22, 2017 - 5:00 AM1 comment

LEIA LARSEN, Standard-Examiner Staff

Scientists and state officials are a small step closer to figuring out what’s blowing in from the shriveled Great Salt Lake.

They’ve suspected a growing exposed lakebed contributes to dust storms along the Wasatch Front and Cache Valley, but couldn’t pinpoint how much dust came from the Great Salt Lake versus other sources. What researchers do know, however, is that the fine particles coming out of dust, such as PM 2.5 and PM 10, cause harmful health effects.

Dust from decimated lakes has caused major human health problems throughout the world, including the Owens Lake bed in California. Even Utah’s Sevier Dry Lake, desiccated from water diverted for farming, is a major source of dust pollution along the Wasatch Front, despite its location hundreds of miles away.

“People have been really concerned about air quality given the amount of exposed (Great Salt Lake) bed,” said Laura Vernon with the Utah Division of Forestry, Fire and State Lands. “I think we’re just now starting to dive into that research.”

Results are now filtering in from a division-funded study about Great Salt Lake’s dust, which could tell researchers more about what it’s doing to our lungs.

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Where the dust blows

Greg Carling, assistant professor in geological sciences at Brigham Young University, collected dust samples in the fall of 2015 and spring of 2016 from playas at the Sevier Dry Lake, the Great Salt Lake, the Tule Valley in Millard County and Fish Springs in Juab County.

At the time of Carling’s study, around 50 percent of the Great Salt Lake’s lakebed was exposed.

The study results are still preliminary and under peer review, but they showed around 40 percent of the particulate pollution during dust storms in Ogden and Logan during Fall 2015 came from the Great Salt Lake. The rest mostly came from the Sevier Dry Lake.

The following spring, almost all of the dust in Ogden and Logan came from Sevier Dry Lake.

“My hunch is that even though we had ... strong winds and dust storms in spring, there must have been something with the (Great Salt Lake) lakebed,” Carling said. “It must have been wet in the spring, and it probably didn’t produce as much dust.”

Salt Lake City and Provo saw almost no dust from the Great Salt Lake in the fall or spring during Carling’s study. That’s likely due to prevailing winds, Carling said, which come from the south.

Rising mercury

Even if only a portion of a dust storm’s source comes from the Great Salt Lake, what’s blowing around could be uniquely problematic.

Farmington Bay is one of the first areas to dry out when lake levels are low, and it borders major population centers in Davis and Weber counties.

The bay’s dust sample results also revealed around 2 nanograms per kilogram of mercury — around double the amount of mercury measured in other parts of the lake, according to the study’s preliminary results. 

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“Whether or not that’s to the level of where we need to be concerned, I’m not sure,” Carling said. “That would probably take further study and probably require some toxicological kinds of studies. I don’t think any of that has ever been done.”

Wayne Wurtsbaugh, a retired limnologist and lake researcher for Utah State University, suspects Farmington Bay’s high mercury levels are a result of the area’s industrial past.

RELATED: If Utah's Great Salt Lake dries up, consequences will be global

In 2012, he took sediment samples from various parts of the lake and analyzed them for metals. He hypothesized that the high levels of metals he was detecting were due to smelters that processed ore on the south shore of the Great Salt Lake and along the banks of the Jordan River.

They also may have come from the Sewer Canal, where oil refineries and other industrial sites once discharged waste into the bay.

“The further north you went from (Farmington Bay), the lower the metals were in sediments,” Wurtsbaugh said.

A draft of other concerns

Beyond high mercury levels, Carling’s preliminary study results show dust blowing from the Great Salt Lake and other sources could be picking up human-made pollution sources along the way, bringing it to breathing level. 

“Because dust particles are so fine, they’re able to scavenge pollution already in atmosphere in urban areas and pull it down,” Carling said. “So if we didn’t get a dust storm, maybe the pollution would be more content hanging out high in atmosphere or blown away by the wind. But dust brings the pollution down with it.”

Carling was able to tie these issues specifically to emissions from the Great Salt Lake by finding unique chemical fingerprints in each dust site. 

He found the isotopes in the metallic element strontium differed considerably in the Great Salt Lake dust versus the other measured dust sources. 

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“I was totally blown away by how well we were able to differentiate different playas,” he said. “What was really nice was how different Sevier Dry Lake and Great Salt Lake were ... moving forward, we now have something we can measure to quantify dust sources.”  

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Utah lawmakers appropriate $200,000 to Forestry, Fire and State Lands each year to conduct research on hot topics at the Great Salt Lake. Carling received $40,000 for his dust study. He has applied for more this year to continue his research. 

“Given how variable dust production is, it can change seasonally from a given place and also with weather patterns,” he said. “Ideally, we’d want to do this for several years to get a really good idea of what’s going on.”

In addition to metals pollution in Great Salt Lake dust, another study out of Utah State University proposes research on algae concentrations and pathogens in the dust, particularly since Farmington Bay is prone to toxic algal blooms. 

Forestry, Fire and State Lands will announce grant recipients by the end of April. Research projects will begin in July. 

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Although generous winter storms increased the amount of snowmelt flowing to the Great Salt Lake, low water levels and an exposed lakebed remain concerns for the division.

“Because it’s such a shallow lake and spread out over so many hundreds of miles, it takes a lot to fill it up,” Vernon said. “If we had five years like this, maybe you’d kind of get back to an average lake. But right now, we’ve got a ways to go.”

Contact Reporter Leia Larsen at 801-625-4289 or llarsen@standard.net. Follow her on Facebook.com/leiaoutside or on Twitter @LeiaLarsen

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