Utah’s Great Salt Lake is evaporating like a giant puddle due to drought and water diversion. This evaporation is exposing the lake bed and, according to a new study, releasing dangerous dust that contains heavy metal elements such as arsenic and lead. Utah’s largest city and state capitol, Salt Lake City, is close to the lake and researchers have warned that the 1.2 million people in the city’s metro area risk being exposed to dangerous chemicals. 

The Great Salt Lake is the largest saltwater lake in the Western Hemisphere but Utah’s state government has been doing everything it can to change that. In the 1980s, the lake measured 8,500 km² (3,300 sq m). A massive pumping project, which rerouted water from the lake into the desert, combined with a long drought, has seen the lake shrink to a current low of just 2,500 km² (950 sq m). 

Regions of the now-exposed lakebed are emitting large quantities of dust. Chemical analysis of these particles has revealed some disturbing results. “You’re talking about a very large dust source located next to a very large population, and you’ve got elevated levels of manganese, iron, copper, and lead,” said co-author Kerry Kelly, a professor of chemical engineering at the University of Utah in a statement. 

High levels of any of these elements in our air is bad news. Lead can cause developmental issues and damage the brain and kidneys. Dust containing the transition metals iron, copper, and manganese can irritate the lungs and lead to inflammation and respiratory conditions like asthma. Excessive levels of arsenic have been linked to respiratory irritation, heart disease and, in severe cases, a type of gangrene called Blackfoot disease. Analysis showed that, when compared to other potential dust sources in the region, Great Salt Lake sediments could spread through the human body more easily. 

“When you breathe in something that’s really reactive, it’s going to interact with the cells inside your lungs and it’s going to cause damage,” Kelly said.

Kelly and her team turned sediment samples into aerosols to find particles small enough to become lodged in lung tissue. The particles’ chemical and physical properties were analyzed using inductively coupled mass plasma mass spectrometry. 

The study not only concluded that chemicals were present in the lake dust but also noted that the monitoring equipment required to work out if residential neighborhoods in Salt Lake City are at risk of exposure has not yet been set up. 

One piece of good news to emerge from the study is that just 9% of the exposed lakebed is currently emitting dust. A protective crust across the rest of the lakebed is currently keeping more toxic elements sealed away. But a preview of what toxic dust can do lies about 900 km (560 mi) to the lake’s south, where the drying Salton Sea has become an environmental catastrophe. 

Kelly’s co-author and colleague Kevin Perry, a professor of atmospheric sciences, said, “It turns out that the dust from Great Salt Lake has more leachable metals that are bioavailable than we would wish.”

The study was published in the journal Atmospheric Environment.