Global Transport and Deposition of 137 Cs Following the Fukushima Nuclear Power Plant Accident in Japan: Emphasis on Europe and Asia Using High-Resolution Model Versions and Radiological Impact Assessment of the Human Population and the Environment Using Interactive Tools Nikolaos Evangeliou,* ,† Yves Balkanski, † Anne Cozic, † and Anders Pape Møller ‡ † Laboratoire des Sciences du Climat et de l’Environnement (LSCE), CEA-UVSQ-CNRS UMR 8212, Institut Pierre et Simon Laplace, L’Orme des Merisiers, F-91191 Gif sur Yvette Cedex, France ‡ Laboratoire d’Ecologie, Systé matique et Evolution, CNRS UMR 8079, Universite ́ Paris-Sud, Bâ timent 362, F-91405 Orsay Cedex, France. * S Supporting Information ABSTRACT: The earthquake and the subsequent tsunami that occurred offshore of Japan resulted in an important loss of life and a serious accident at the nuclear facility of Fukushima. The “hot spots” of the release are evaluated here applying the model LMDZORINCA for 137 Cs. Moreover, an assessment is attempted for the population and the environment using the dosimetric scheme of the WHO and the interactive tool ERICA, respectively. Cesium-137 was deposited mostly in Pacific and Atlantic Oceans and North Pole (80%), whereas the rest in the continental areas of North America and Eurasia contributed slightly to the natural background (0.5-5.0 kBq m -2 ). The effective dose from 137 Cs and 134 Cs (radiocesium) irradiation during the first 3 months was estimated between 1-5 mSv in Fukushima and the neighboring prefectures. In the rest of Japan, the respective doses were found to be less than 0.5 mSv, whereas in the rest of the world it was less than 0.1 mSv. Such doses are equivalent with the obtained dose from a simple X-ray; for the highly contaminated regions, they are close to the dose limit for exposure due to radon inhalation (10 mSv). The calculated dose rates from radiocesium exposure on reference organisms ranged from 0.03 to 0.18 μGy h -1 , which are 2 orders of magnitude below the screening dose limit (10 μGy h -1 ) that could result in obvious effects on the population. However, these results may underestimate the real situation, since stable soil density was used in the calculations, a zero radiocesium background was assumed, and dose only from two radionuclides was estimated, while more that 40 radionuclides have been deposited in the vicinity of the facility. When monitoring data applied, much higher dose rates were estimated certifying ecological risk for small mammals and reptiles in terms of cytogenetic damage and reproduction. ■ INTRODUCTION On March 11, 2011 (14:46 local time), a great earthquake occurred in Eastern Japan (Tohoku District) resulting in severe damage to the area and to the residents. The magnitude was estimated to be 9.0 causing a large number of deaths. Due to the earthquake, big tsunamis developed and hit the Eastern Coast of Japan. 1 There are 17 nuclear power plants (NPPs) in 13 prefectures of Japan consisting of 54 reactors. In Fukushima prefecture, 10 boiling water reactors (BWR) were operated. The Fukushima Dai-ichi NPP located on the East Coast (Supporting Information Figure S2) was also attacked by the tsunamis and a simultaneous loss-of-offsite power took place. The offsite power lines were lost due to damage of the breakers and 12 emergency diesel generators (EDGs) automatically started. 2 The four BWRs were hit by the first tsunami 41 min after the earthquake and by the second one 8 min later. The ground level of the site is 10 m above sea level, and the tsunami reached 4-5 m above ground level. 3 When the tsunamis entered the NPP, the emergency generators of the stations lost their capabilities, and electric power was disrupted. 4,5 As a result, the cooling systems were damaged, internal pressure levels increased due to extreme heating of the cooling water, and hydrogen explosions occurred during March 12-15. A lot of fission products including 131 I, 134 Cs, and 137 Cs were released into the environment. The refractory radioactive materials (e.g., Pu isotopes) were deposited close to the NPP, whereas the most labile ones (e.g., cesium and iodine isotopes) were transported as a fallout plume over long distances following the prevailing meteorology. The rainfall started in Japan on March 15, so the radioactive materials were deposited due to wind direction and rainfall northwesterly from the NPP. The objective of the present paper is to study the global transport and deposition of the 137 Cs released after the Received: January 27, 2013 Revised: April 24, 2013 Accepted: May 1, 2013 Published: May 1, 2013 Article pubs.acs.org/est © 2013 American Chemical Society 5803 dx.doi.org/10.1021/es400372u | Environ. Sci. Technol. 2013, 47, 5803-5812