Jiji Press, Sept. 7, 2014 (emphasis added): Some 2 trillion becquerels of strontium-90 and cesium-137 may have flowed into the bay [of the] Fukushima No. 1 plant during the 10 months to May this year, it was learned Sunday… highly radioactive water may be leaking into the bay… According to Tepco documents, some 4.8 billion becquerels of strontium-90 and 2 billion becquerels of cesium-137 are estimated to have flowed into the plant’s bay per day, based on their average concentrations near a water intake for the Nos. 1-Nos. 4 reactors… 1.46 trillion becquerels for strontium-90 and 610 billion becquerels for cesium-137 [during the past 10 months]… Since tainted water in the plant has other substances, the radioactive contamination of water in the plant’s bay is believed to be more serious… radioactive materials in the plant’s bay spread out into the open sea as the tide ebbs and flows. Also, it is noted that part of contaminated groundwater may be flowing directly into the open sea.
Edwin Lyman Senior Scientist at the Union of Concerned Scientists, July 14, 2014 (at 21:30 in): In addition to what was emitted into the air, there’s leakage into the sea. Now these damaged reactors… these cores melted through the steel vessel, they damaged the containments, there are holes, and they’re leaking water like Swiss cheese. But you have to keep pumping water into the reactors because the cores are still hot. Even today… they’re pumping water into the reactors… It’s finding its way through these holes in the bottom of the reactor vessels, and the containments, into the basements of the buildings, mixing into the soil, and mixing with groundwater… There’s a constant flow of groundwater through the site, mixing with the radioactivity that every day is continuing to build up and being washed into the sea… So you have a site where you still have 3 damaged cores, the operators do not know the condition of the nuclear fuel… and it’s going to take many years before they’re actually able to send people in to actually investigate what actually happened during the accident. So to talk about decommissioning — it’s still premature, because we don’t have a good sense of where the nuclear fuel is and to the extent to which it spread within the plants.