Current Situation and Challenges at Fukushima: Hands-on Measurements of Radiation Contamination after Fukushima Daiichi Nuclear Power Plant Accident

摘要

An oceanographic investigation within 1.0km radius of Fukushima Daiichi nuclear power plant (FDNPP) was carried out in September 2013, independent of the Government of Japan. Samples of seawater and seafloor sand were collected near the sewage outlets and in front of the harbor at the FDNPP. The level of seawater radioactivity did not show evidence of immediate harm to the health of the people. However, sedimentation of radionuclides to the seafloor was estimated from the results of seafloor sand. We found strontium-90 at detectable levels in the sand samples of all three points. As far as the impact of biological concentration is concerned, it would be essential to monitor the radioactivity of seawater deeper down and seafloor sand rather than that of subsurface. Regulation for both total volume and concentration should be considered.