Why are bananas radioactive?
You'd need to eat 10 million at once for a lethal dose.
The answer
Bananas contain potassium, and about 0.012% of all natural potassium is the radioactive isotope potassium-40, which has a half-life of 1.25 billion years. A single banana contains roughly 15 becquerels of radioactivity. This has led to the informal 'banana equivalent dose' unit in radiation science. However, your body tightly regulates potassium levels, so eating extra bananas simply causes you to excrete more - the radioactivity never accumulates to dangerous levels.
Source: Health Physics Society
- radioactivity
- physics
- food science
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