Radioactive water dumped into the sea question?

According to a news article on CNN:

"In all, about 11,500 tons of radioactive water that has collected at the nuclear facility will be dumped into the sea, officials said Monday, as workers also try to deal with a crack that has been a conduit for contamination."

How will this 11,500 tons of radiactive water affect the ocean? How will it affect our California beaches and environment?