Does drinking mineral water contain radiation?


Question:

Does drinking mineral water contain relatively high amount of radioactive materials depending on the places where the water is taken? (Male, 30s, Tokyo)

Answer:

You maybe surprised to hear that drinking mineral water contain radioactive materials. Radioactive materials do exist in nature. We are exposed to approximately 290 microsievert (μSv) of radiation in our daily food.

Calcium, sodium, magnesium, and potassium are major ingredient minerals in mineral water. The isotope potassium, potassium-40, is radioactive material in the water.(30.4 becquerel (Bq) per 1 g)

There is an international rule for the concentration of the radioactive materials in drinkable mineral water. The amount of Potassium in the water varies dependent on the places it is collected. (Some are less than 1mg, some are more than 50 mg)

If 1L of the drinking mineral water contains 50 mg of potassium, then,
(50÷1000)g × 30.4 = 1.52 Bq of radiation.

1 Bq of potassium-40 would be equal to 6.2 × 10-9 Sv in our bodies.
So, the radioactive materials in 1L of drinking mineral water effect to expose to our bodies,
1.52 Bq × 6.2×10-9 Sv/Bq = 9.4 × 10-8 Sv = 0.094 μSv
Consequently, the radiation levels of drinkable mineral water would be relatively lower.


Science Communicator: Maki Takata