Transfer of 131I from Fukushima to the vegetation and milk in France.

Iodine-131 and various other radionuclides were released into the atmosphere from the damaged Japanese reactors of Fukushima Dai-ichi from 12 to 22 March 2011. The contaminated air mass was detected in France after 24 March; samples of grass, vegetables, and milk have been analyzed for 131I by the IRSN, considering the fact that few values of iodine-131 transfer parameters have been directly measured in situ, due to the radioactive decay of this isotope. Data are compared with calculated values according to the air iodine concentration. The apparent dry deposition velocity of iodine on grass is therefore estimated to range between 1 × 10–3 and 5 × 10–3 m s–1 from site to site. In addition, the grass to milk transfer factors are 2.8 × 10–2 and 3.6 × 10–3 d L–1 for goat’s and cow’s milk respectively. These parameters fit well with the current values usually considered for radioecological assessment.