The ocean is very much not a fine place for perpetual dumping of large amounts of radioactive water, because of the long half lives of various radioactive contaminants. Humans eat the fish, that swim in the ocean. Dumping dangerous wastes into the ocean is not smart.
Caesium-137 and Strontium-90 are examples. They can get into the seafood chain and very much do increase cancer risks.
Unlike chemical contamination (e.g. mercury) radiation doesn't bio-accumulate. The seafood won't have higher radiation levels than the water (less than a banana).
> Unlike chemical contamination (e.g. mercury) radiation doesn't bio-accumulate.
That is a very, very misinformed or misleading statement. Caesium-137 and Strontium-90 have half lives of around 30 years and do get into seafood. There are warnings given out often about radioactive contaminated seafood. That's why Fukushima's radioactive water dumping was such a problem and neighboring countries had issues with it.
Seafood can and does get radioactive contamination and this increases cancer risks in humans that consume it.
Caesium-137 and Strontium-90 are examples. They can get into the seafood chain and very much do increase cancer risks.