Which statement correctly defines exposure and dose?

• A. Exposure is the amount of hazard present in the environment, regardless of contact.
• B. Dose is the exposure concentration in the environment.
• C. Exposure and dose refer to the same concept.
• D. Exposure is the contact with a hazard; dose is the amount absorbed by the body.

Answer: (D)

Distinguishing exposure from dose is key. Exposure means you come into contact with a hazard in the environment—the hazard is present and you are in a situation where contact is possible or occurs. Dose is the amount of that hazard that actually enters or is absorbed by your body, after considering how it entered (breathing, skin, swallowing), how long you were exposed, and your body’s handling of it. That’s why the correct statement is that exposure is contact with a hazard, while dose is the amount absorbed by the body. The other ideas mix up where the hazard is (environmental presence vs. what your body actually takes in), or treat exposure and dose as the same thing, which they are not. For example, you can be exposed to a chemical in the air, but the dose depends on how much inhaled, how long, and how your body processes it.