From Reuter's today:
Japan's biggest utility estimated around 4,720 trillion becquerels of cesium-137 and iodine-131 was released into the Pacific Ocean between March 21 and April 30, but researchers at the Japan Atomic Energy Agency (JAEA) put the amount at 15,000 trillion becquerels, or terabecquerels.
Government regulations ban shipment of foodstuff containing over 500 becquerels of radioactive material per kg.
