Annual Limit on Intake (ALI) is defined as which of the following?

• A. The maximum annual intake of radioactive material allowed given exposure conditions.
• B. The maximum time a worker can be exposed to a source in a year.
• C. The maximum allowable air concentration in a work area.
• D. The maximum annual dose to the skin.

Answer: (A)

The idea is to express how much radioactive material a person can take into their body in a year without exceeding the regulatory dose limit. Annual Limit on Intake represents the maximum activity of a radionuclide that can be inhaled or ingested in one year under the specified exposure conditions, given how that material behaves in the body and the associated dose per unit intake. In other words, it translates the dose limit into an intake amount using dose coefficients, so you can compare a material’s activity to this limit and know whether monitoring is needed or if the intake would stay within allowed bounds. This is about internal exposure from intake, not about how long someone is exposed externally, nor about workplace air concentration, nor about skin dose.