– Scientists: Plutonium released from Fukushima “is of radiological concern”; Reactor must be source, not spent fuel pool — Study: Plutonium found 120 km from plant; “Pu and non-natural uranium certainly increased in environment” (ENENews, April 21, 2014):
Environmental Science & Technology (ACS Publications), Apr. 1, 2014: Airborne Plutonium and Non-Natural Uranium from the Fukushima DNPP Found at 120 km Distance a Few Days after Reactor Hydrogen Explosions — Plutonium (Pu) and non-natural uranium (U) originating from the Fukushima Daiichi Nuclear Power Plant (FDNPP) were identified in the atmosphere at 120 km distance from the FDNPP […] Comparing the time series of analytical data on Pu and U obtained in this study with previously reported data on Pu, U, and radioactive Cs, we concluded that Pu and non-natural U from the FDNPP were transported in the atmosphere directly over a 120 km distance by aerosol and wind within a few days after the reactor hydrogen explosions. Effective dose of Pu were calculated using the data of Pu: (130 ± 21) nBq/m3, obtained in this study. We found that the airborne Pu contributes only negligibly to the total dose at the time of the incident. However the analytical results show that the amount of Pu and non-natural U certainly increased in the environment after the incident.
Actinide Emissions from Nuclear Accidents: Recent and Coming Developments (pdf), Georg Steinhauser & Brett Rosenberg, Department of Environmental and Radiological Health Sciences, Colorado State University, 2014: The Fukushima nuclear accident will remain in public memory as one of the worst environmental disaster in recent years. […] plutonium and other transuranium elements have been emitted in smaller amounts and still remain the most understudied contaminants. […] we were able to detect trace amounts of reactor-derived plutonium in two vegetation samples from the vicinity (0.5 and 16 km distance) of the Fukushima Daiichi NPP. The characteristic 240Pu/239Pu atomic ratio […] proved that a nuclear reactor must have been the source of these contaminations. […] our results indicate a particulate release of plutonium which is of radiological concern upon incorporation.