Fukushima's Groundwater Is Contaminated

At different levels than earlier reported.

It sounds somewhat scary, but it's important to understand what the regulatory levels are based on.



They are based on drinking a certain amount of water per day, all year (a total of 7.3E5 ml in the U.S. regulations).  There is a low annual dose limit for the general public (100 mrem/year in the U.S.).

So having Sr-90 at 30 times the limit isn't terrible unless that's your only source of water for a very long time.  But even then, it's not horrific, since we're talking about (30 x 100 mrem/yr = 3 rem/yr).  Radiation workers are allowed 5 rem/yr.  If you solely drank it for 20 years (and ignoring radioactive decay), you'd have 60 rem.  That would increase the average person's cancer risk by about 6%.