Which of the following is NOT an element of the exposure pathway?

• A. Source
• B. Exposure Route
• C. Emission
• D. Receptor Population

Answer: (C)

The idea being tested is what components make up an exposure pathway. In this framework, the elements you track are where the contaminant comes from (the source), how people come into contact with it (the exposure route), and who is exposed (the receptor population). Emission describes the release of the contaminant from the source into the environment. While it drives the amount of contaminant that could reach people, it is a release process rather than one of the pathway’s elemental steps. So emission isn’t counted as an element of the exposure pathway; it’s part of the release that feeds the pathway. For example, a factory may be the source, inhalation could be the exposure route, and nearby residents the receptor population; the amount released (emission) influences exposure but isn’t itself a separate pathway element.