Off the coast of SF, near the farallon islands is a huge nuclear waste dump the US has been using since the 50's. THere's tens of thousands of barrels down there, the sunken carrier USS Independence (used for testing nukes on), and plenty of it is exposed to sea life and the water...for that last 6 decades.
http://www.sfweekly.com/2001-05-09/news/fallout/ <-- good read if you have time.
In short, the country used this as the first and main nuclear dump site. The UC Berkeley (Livermore site) nuke facilities did alot of testing on animals and other such things and dumped it all, in barrels in this dump site. One guy who worked the barge from '55 to '59 had the job of dumping the barrels when the barge got full, and the ones that floated, he shot at until they sunk. 30 miles off the coast. It's one of the biggest and best fisheries in the Pacific coast so alot of your local supermarket seafood comes from there. Num nums! No wonder the great whites in this area attack humans so much! lol