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Yang, W. F., University of Southern Mississippi, Stennis Space Center, USA, wyang.xmu@gmail.com
Guo, L. D., University of Southern Mississippi, Stennis Space Center, USA, laodong.guo@usm.edu

RESIDENCE TIME OF ATMOSPHERIC RADIOIODINE (131I) FROM THE FUKUSHIMA ACCIDENT

Elevated radioiodine (131I) has been reported in aerosols and precipitation after the Fukushima nuclear disaster, yet the timescale and transport mechanism of 131I remain poorly understood. Time series depositional fluxes of 131I, 210Pb and 210Po were determined to examine the depositional dosage of 131I in southern Mississippi and its resident timescale in the atmosphere after the Fukushima accident. The accumulative 131I flux was 4.6±0.2 Bq ⁄ m2 during the maximum fallout, resulting in a detectable 131I activity of 6.7±1.0 mBq ⁄ L in surface waters from the Pearl River, Mississippi. Radioiodine reached southern United States within 11 days, giving rise to concurrent 131I peak and anomalous 210Po ⁄ 210Pb ratio in southern Mississippi. The removal rate of 131I out of the atmosphere, derived from a definite 131I integral model, ranged from 0.03 to 0.14 d-1 with an average of 0.08±0.02 d-1, which corresponds to a residence time of 20±4 days for atmospheric 131I, consistent with the timescale constrained by the 210Po ⁄ 210Pb disequilibrium technique. These results imply that radioiodine was largely removed from the atmosphere within three weeks.

Poster presentation

Session #:088
Date: 2/21/2012
Time: 17:00 - 18:00
Location: Poster/Exhibit Hall

Presentation is given by student: No

PosterID: B1017