EPA-Expo-Box (A Toolbox for Exposure Assessors)
Fate and Transport
Fate and transport processes “link” the release of contaminants at a source with the resultant environmental concentrations to which receptors can be exposed. When a contaminant is released from a source, it is subject to transport and transformation in the environment. Compounds can also transfer from an environmental medium (e.g., air, soil, water) to biota, including plants and animals used as a food source. For additional information on the fate and transport of contaminants within environmental media and biota, see the Air, Soil and Dust, Water and Sediment, Food, and Aquatic Biota Modules in the Media Tool Set of EPA-Expo-Box.
The fate and transport of chemicals released from consumer products will be generally governed by their physicochemical properties and the characteristics of the environment into which they are released. For example, chemicals with a high vapor pressure would be more likely to remain in the air compared with low vapor chemicals that might settle with dust on surfaces. For chemicals released to indoor air, characteristics of the building (e.g., air exchange rates, ventilation, room volumes) will influence dispersion and concentrations of contaminants in indoor air. The residence time of contaminant-laden dust will be influenced by human behavior that removes dust such as frequency and duration of vacuuming. For chemicals that are released or transported outdoors, meteorological factors (e.g., temperature, sunlight, wind, precipitation) would contribute to their fate and transport. For chemicals released to water, the nature of the water body—such as flow rates and water characteristics like pH, salinity, and dissolved oxygen level—would affect their fate and transport.
The following tools provide information related to the fate and transport of contaminants that might be found in consumer products. In some of these resources, physicochemical properties of contaminants are also described. See the Chemical Classes Tool Set of EPA-Expo-Box for more information on the toxicity, physicochemical properties, and other characteristics of specific groups of chemicals including organics, inorganics and fibers, pesticides, and nanomaterials.