Earlier quoted context omitted.
10,000 is very high and this level will be lowered hopefully in time. In Ontario Canada: 20 Bq/L limit proposed by the Ontario Drinking Water Advisory Council (ODWAC) 190 is 10 times that limit. This isn't only about drinking water it's about eating seafood that has absorbed these chemicals (or eaten many fish who have absorbed them). I could understand the caution around seafood in that area for a period of time.
I regret to tell you the ODWAC is made up of unqualified morons preying on your fears then. The ocean's average radioactivity is 12Bq/L, and there's a _lot_ of water. A single banana is 20Bq already. Dump a few million litres of 10000Bq/L water in the ocean over a few years, and the average radioactivity goes to... Still 12Bq/L
This is unlike, say, naturally radioactive carbon or potassium isotopes, that have a relatively constant concentration in the animal's body over it's life time - if a fish eats some high potassium food, it will excrete an equivalent of his own equally radioactive amount to maintain homeostasis.
It's for this exact reason the net "banana dose" of radiation, unless you are potassium deficient, is in fact zero.