Reassessment of the radiocesium resuspension flux from contaminated ground surfaces in eastern Japan

Abstract. Resuspension of 137Cs from the contaminated ground surface to atmosphere is essential for understanding environmental behaviors and estimating external inhalation exposure residents. Kajino et al. (2016) assessed resuspension flux bare soil forest ecosystems in eastern Japan 2013 using a numerical simulation constrained by air concentration measurements. However, was found underestimate observed deposition amounts 2 orders magnitude. The reason this underestimation that assumed resuspended carried submicron aerosols, which have low rates. Based on observational indications dust bioaerosols are major carriers 137Cs, new performed with higher rates both concentrations amounts. In estimation, total areal annual 25.7 TBq, equivalent 0.96 % initial (2.68 PBq). Due rapid rates, redeposition amount also large at 10.6 approximately 40 137Cs. rate through (0.96 yr−1) seems slow, but it (2.6 × 10−5 d−1) may not be negligibly small compared actual decreasing trend ambient gamma dose obtained Fukushima Prefecture after radioactive decay plus 134Cs subtracted (1.0–7.9 10−4 d−1): can account 1 %–10 due decontamination natural land processes. current underestimated city winter more than an order magnitude, indicating presence additional sources. site surrounded roads. Heavy traffic wet muddy roads snow removal operations could generate superlarge (approximately 100 µm diameter) road or salt particles, included model might contribute site.