Dr. Hans-J. Dammschneider, Vorstand, Klimaforschung ifhgk.org: The natural radioactivity of sea water is 12 Becquerel / l. A Becquerel is one radioactive decay per second. According to the German Radiation Protection Ordinance, 3.4mSv / a are currently harmless. That would be the equivalent of around 260,000 Bq ... with 80l of mineral water per year you have already reached the total permitted amount !? Conclusion: Smoking (8.0mSv / a) is definitely more harmful than sea water ... even than that in front of the Fukushima power plant (0.065mSv / a).