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Final Report: Evaluation of the Potential Toxicity of Dust Palliatives Used in Alaska
Citation:
Zimmerman, J., K. Krauss, B. Schumacher, L. Bertelsen, N. Gavrelis, AND C. Dussuncao. Final Report: Evaluation of the Potential Toxicity of Dust Palliatives Used in Alaska. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-20/081, 2020.
Impact/Purpose:
To computationally evaluate the potential toxicity of historically utilized dust palliatives in the state of Alaska.
Description:
Unpaved road surfaces are commonplace in Alaska, where more than 50 percent of state-owned roads and the majority of local and private roads are unpaved (UAF/AUTC, 2013). Various sources can cause releases of fugitive dust, such as vehicles (e.g., all-terrain vehicles [ATVs]) traveling on unpaved road surfaces (e.g., dirt roads, gravel roads, unpaved runways), and wind blowing across these surfaces and gravel pits (ADEC and EPA, 2018). Much of the fugitive dust in Alaska comprises particulate matter that is less than 10 microns in size (PM10), which can lead to adverse health effects in some exposed individuals (Withycombe and Dulla, 2006). Fugitive dust has other potential negative impacts, such as impairing driver safety by reducing visibility and requiring costly and frequent road and runway maintenance (UAF/AUTC, 2013). Dust palliatives are products used worldwide to suppress fugitive dust. For several decades in the state of Alaska, tribal, state, urban, and rural city governments have been applying palliatives to control and suppress dust on unpaved road surfaces. Palliative use dates back to the 1960s with the application of salt-based palliatives, such as calcium chloride and magnesium chloride (Connor, 2015). Due to availability, effectiveness, and cost, common palliatives used in Alaska include water, salt-based palliatives, synthetic fluids, and polymers (Milne, 2015). EPA (2016) documents all of the different types of palliatives used in Alaska as reported by the State of Alaska Department of Transportation & Public Facilities (Alaska DOT&PF), locations in the state where application is generally known to occur, and typical application methods (see Section 4.1 in EPA, 2016 for more information). In 2015, ERG assisted EPA by performing an extensive literature review to investigate dust palliatives used on road surfaces in the state of Alaska, the fate and transport of these palliatives in the environment, the documented effects to human health and the environment, and the applicable regulations associated with palliative use in Alaska. The findings of that report are documented in EPA, 2016. The purpose of this report is to summarize the follow-on effort performed in 2019.