The banana equivalent dose is the dose of ionizing radiation to which a person is exposed by eating one banana. Bananas contain potassium. Natural potassium consists of 0.0117% of the radioactive isotope K (potassium-40) and has a specific activity of 30,346 becquerels per kilogram, or about 30 becquerels per gram. The radiation dose from eating a banana is about 0.1 μSv. The value of this reference dose is given as "1" and thus becomes the "unit of measurement" banana equivalent dose. Consequently, other radiation exposures can be compared to the consumption of one banana. For example, the average daily total radiation exposure of a person is 100 banana equivalent doses.