Back of the envelope: If there are 100,000 gallons (400 tons) of radioactive water leaking into the pacific ocean in Japan per day, to be diluted by the 187 q

Back of the envelope: If there are 100,000 gallons (400 tons) of radioactive water leaking into the pacific ocean in Japan per day, to be diluted by the 187 quintillion gallons of water already there (not hyperbole, a reasonable estimate based on 70 cubic million miles of water), than the ocean is 1 1,880,000,000,000,000th of a percent more radioactive per day. Or basically zero. It would be interesting to calculate how much more radioactive the water gets from alpha particles in sunlight shining on the water than from Fukushima, but I'm not feeling up to it at the moment.