Physics – 5.2.1 Detection of radioactivity | e-Consult

Food and drink contribute to background radiation exposure primarily through the presence of naturally occurring radioactive isotopes, particularly potassium-40 (⁴⁰K) and, to a lesser extent, radium-226 and radium-228. Potassium-40 is a common isotope found in many plants and animals, as it is essential for biological processes.

Foods like bananas, potatoes, milk, cheese, and seafood contain higher levels of potassium-40 than other foods. The significance of this contribution is that it represents a continuous, low-level exposure to radiation throughout our lifetime. While the levels are generally low, they add to the overall background radiation dose.

The amount of radiation absorbed from food and drink depends on the concentration of radioactive isotopes in the food and the amount of food consumed. While the radiation dose from food is relatively small compared to other sources like radon gas, it is a constant and unavoidable source of exposure.

• Potassium-40 (⁴⁰K): Found in many plants and animals.
• Examples: Bananas, potatoes, milk, cheese, seafood.
• Significance: Continuous, low-level exposure.
• Other Isotopes: Radium-226 and Radium-228 (present in smaller amounts).