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EPA-Expo-Box (A Toolbox for Exposure Assessors)

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Inorganics and Fibers


The relevant pathways of exposure to inorganics vary based the type of inorganic. Exposure to inorganics occurs most commonly from ingestion (food, soil [incidental], drinking water) or inhalation (dust). Exposure from dermal contact (e.g., from contaminated soil) can also occur. Exposure to fibers such as asbestos occurs mainly through inhalation. Lead and mercury have been studied at length due to the health effects related to exposure, so examples related to those metals are provided below. The Routes Tool Set of EPA-Expo-Box provides additional information and resources organized by route.

Route Example(s) for Inorganics and Fibers
  • Divalent mercury can be transformed to MeHg by anaerobic microbes. MeHg readily bioaccumulates in fish (unlike divalent mercury) and these fish may be ingested by humans. The most common way people are exposed to any form of mercury is by eating fish containing MeHg.
  • In general, lead exposure can occur by ingesting dusts, drinking water, or eating foods that contain lead.
  • For children, exposure can result from swallowing paint chips or dust from deteriorated lead-based paints.
  • Exposure to inorganics might occur by inhalation of soil particulates.
  • When asbestos-containing materials are damaged or disturbed, microscopic fibers become airborne and can be inhaled.
Dermal contact
  • Indirect exposure to inorganics in dust could occur by contacting dust that has settled on carpets, floors, clothing, counter tops, or other surfaces.

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