Evidence of the radioactive fallout in France due to the Fukushima nuclear accident

Radioactive fallout due to the Fukushima reactor explosion in Japan was detected in environmental samples collected in France. The presence of I-131 in aerosols (200 +/- 6 mu Bq m(-3)) collected at the Pic du Midi observatory, located at 2877 m altitude in the French Pyrenees, indicated that the Japanese radioactive cloud reached France between 22 and 29 March, i.e. less than two weeks after the initial emissions, as suggested by a Cs-137/Cs-134 ratio of 1.4. Cesium radioisotopes (Cs-134 and Cs-137) were not detected in this sample but they were present in the aerosol sample collected the next week, i.e. between 29 March and 05 April (about 10 mu Bq m(-3)). We also report I-131 activities measured in grass (1.1-11 Bq kg(-1): fresh weight) and soil samples (0.4 Bq kg(-1)) collected in the Seine River basin between 30 March and 10 April. The Cs-134 from the damaged Fukushima power plant was also detected in grass collected in the Seine River basin between 31 March and 10 April (0.2-1.6 Bq kg(-1) fresh weight, with a Cs-137/Cs-134 ratio close to 1, which is consistent with Fukushima radioactive release). Despite the installation of a network of nested stations to collect suspended matter in the upstream part of the Seine River basin, I-131 was only detected in suspended matter (4.5-60 Bq kg(-1)) collected at the most upstream stations between 30 March and 12 April. Neither I-131 nor Cs-134 has been detected in environmental samples since the end of April 2011, because of the rapid decay of I-131 and the very low activities of Cs-134 (about 400 times lower than after Chernobyl accident). (C) 2012 Elsevier Ltd. All rights reserved.