Researchers found that the sediments from the exposed playa of Utah’s Great Salt Lake are potentially more harmful than other major dust sources impacting air quality in the region. Chemical analysis revealed elevated levels of metals such as arsenic, lithium, manganese, iron, copper, and lead in the aerosolized sediments. These metals can cause lung irritation and inflammation, leading to adverse health effects like asthma. The presence of these pollutants in the dust emitted from the lakebed poses a significant concern due to the proximity of the lake to a large population center along the Wasatch Front.
The Great Salt Lake, as a terminal body receiving runoff from a wide drainage basin, accumulates metals from natural sources and human disturbances in its sediments. State officials in Utah have identified the potential for harmful dust pollution from the lakebed as a priority. Studies have shown that the dust from the lakebed disproportionately affects disadvantaged neighborhoods in Salt Lake County, raising environmental justice concerns. Researchers from the University of Utah are working to understand the levels of toxic metals in the lakebed sediments to address the issue effectively.
A team led by U biologist Michael Werner’s lab conducted a study to characterize levels of toxic metals deposited in submerged lakebed sediments during the record-low water year of 2021. The research indicated changes in metal concentrations since the mining era, with some metals like lead and zinc decreasing due to the decline in mining activities, while mercury levels have surprisingly increased. However, it is unclear whether these pollutants are being blown into populated areas during wind events, as monitoring equipment has not yet been deployed downwind of the lake to capture the dust effectively.
To better understand the quality of the dust emitted from the Great Salt Lake playa, researchers analyzed sediment samples from the lakebed along with samples from other dust sources in the Great Basin. The study compared the reactivity and bioavailability of the sediments, finding that the dust from the Great Salt Lake had higher levels of leachable metals that are bioavailable. The analysis also revealed high oxidative potential in dust associated with metals like copper, manganese, iron, and aluminum, indicating potential health risks from inhaling the particles.
Researchers have identified “hotspots” on the playa of the Great Salt Lake that contain sediments enriched with potentially toxic elements. Only a small percentage of the exposed lakebed emits dust, with most of the playa covered by a hardened layer that keeps the sediments in place. Studies are ongoing to monitor the playa crusts over time and determine the extent of the threat to air quality. Initial findings suggest that the broken layers on the playa reset fairly easily, potentially mitigating the impact on air quality in the region.
The latest study conducted by University of Utah researchers is the first to analyze the dust’s oxidative potential and its ability to react with oxygen. By aerosolizing sediment samples and isolating fine particles smaller than 10 micrometers, the team was able to determine the elemental makeup of the particles and their bioaccessibility. The findings indicate that the dust from the Great Salt Lake has a higher level of leachable metals and oxidative potential compared to other dust sources in the region. These results underscore the importance of further research and monitoring to assess the health risks associated with airborne sediments from the lakebed.
