EPA-Expo-Box (A Toolbox for Exposure Assessors)
Soil and Dust
- Fate & Transport
- Calculation Tools
Contaminated media to which people might be exposed include air, water and sediment, soil and dust, food, aquatic biota, and consumer products. Soil can become contaminated as a result of direct or indirect discharges, deposition of contaminants from the atmosphere, erosion of soil and runoff flow, and other processes. Sources of contaminants to indoor dust can include use of consumer products or emissions from building materials or furnishings. Outdoor soil and dust that has been tracked or has migrated indoors are other possible contributors to indoor dust. Soil and dust can serve as reservoirs of historic sources of contamination.
Direct exposure to contaminants in soil and dust can occur by intentional ingestion (e.g., PICA or GEOPHAGY), incidental ingestion (e.g., from hand-to-mouth contact), or via dermal contact. Indirect exposure to soil or dust contaminants could also result from transfer and subsequent contact with other media (e.g., uptake from soil into food crops and subsequent ingestion). Indoor or outdoor dust that is airborne represents a potential inhalation exposure. This potential exposure pathway is discussed in the Air Module of the Media Tool Set in EPA-Expo-Box. The concentrations of contaminants in soil and dust at the point of exposure may differ from the concentration at the source as a result of fate and transport processes (e.g., dispersion, biodegradation). Various tools are available for evaluating sources and releases of contaminants to soil and dust, fate and transport processes, and potential exposure concentrations. Exposure factors, calculation tools, and guidance for assessing exposure to contaminants in soil and dust are also provided.