Reply #31: Coliform bacteria and rip currents are more of a beach hazard than 40K

[jpak]

11 Bq per liter is extremely low level of activity.

Even if you spent all your time in the ocean, your internal 40K dose would be much higher than your external dose (only ~10% 40K decays are gamma branches, the rest are beta emissions that would not penetrate your skin or travel very far through water).

So yeah, it is trivial.