Reactive dust from the Great Salt Lake may have health consequences

Dust pollution is known to contribute to asthma and heart and lung disease. But dust blowing from the Great Salt Lake in Utah can cause an additional unwanted shock.

Metals in dust and sediments around the Great Salt Lake are more reactive than dust from nearby lake beds, researchers report in November. Atmospheric Environment. When inhaled, the dust has the potential to cause inflammation, although the actual impacts on humans in the area will require further study.

The Great Salt Lake is steadily shrinking as drought, climate change and consumption drain water faster than it can be replenished, leaving over 1,900 square kilometers of the lake bed exposed (SN: 17.4.23). As the lake dries up, it leaves behind dust laden with metals, minerals and sediments that were carried into the lake from upstream.

To better understand the composition of the dust, chemical engineer Kerry Kelly and colleagues aerosolized samples collected from around the lake. They then filtered out any dust particles larger than 10 micrometers, leaving only dust particles small enough to inhale.

Analysis of respirable particles revealed several metals — including manganese, copper, iron and lead — in higher concentrations than dust from other nearby playas. Lithium and arsenic were also present at levels that exceeded the US Environmental Protection Agency’s regional control levels, a benchmark for further risk assessment.

The team also found that the oxidative potential of Great Salt Lake dust, which indicates how likely the dust is to generate reactive oxygen species, is generally higher than that of dust from other nearby lakes. Reactive oxygen species are unstable oxygen-containing molecules that interact with—and sometimes damage—molecules in living cells.

“Our body has all kinds of antioxidants,” says Kelly, of the University of Utah in Salt Lake City. These compounds allow us to breathe and handle reactive oxygen species—up to a point. “However, if we get too many of these reactive particles or reactive species entering our lungs, it can cause an imbalance. Then that can lead to inflammation, and then inflammation leads to a number of negative health effects.”

But experts advise not to draw quick conclusions. “I think it’s good to look at environmental components and look at their potential to have this or that effect,” says David Lo, a biomedical scientist at the University of California, Riverside. “But then you want to ask on the same side, is there any evidence that people are actually being harmed?” Linking exposure to highly oxidative dust to specific public health outcomes would require more data on the extent of exposure and studies linking oxidative potential to specific health concerns, he says.

Kelly agrees. “I don’t mean, ‘the sky is falling, we’re all going to die.'” Rather, she says, the study “shows that dust from the Salt Lake is potentially a significant health concern, so we need to do more work.” Utah has funding for equipment to measure the rate at which dust from the Great Salt Lake blows into nearby cities, she says, but it hasn’t been deployed.

“We also need to get more water into the Great Salt Lake,” Kelly says, “because that’s really the solution.”