Radioactive iodine is now at scary levels in the ocean near Japan's broken reactors. But we're advised not to worry because the area has been evacuated and fishing has been stopped.
Also, radioactive iodine will decay quickly and become non-radioactive iodine (this is true).
What this doesn't tell us is whether

other radioactive elements that last longer are also leaking. One expert says that more releases are likely because it
appears that one reactor core has suffered a meltdown.
I think we should expect more bad news about our radioactive ocean, including some elements that are more worrying than iodine.