Validation of 131I ecological transfer models and thyroid dose assessments using Chernobyl fallout data from the Plavsk district, Russia

Abstract

Within the project “Environmental Modelling for Radiation Safety” (EMRAS) organized by the IAEA in 2003 experimental data of 131I measurements following the Chernobyl accident in the Plavsk district of Tula region, Russia were used to validate the calculations of some radioecological transfer models. Nine models participated in the inter-comparison. Levels of 137Cs soil contamination in all the settlements and 131I/137Cs isotopic ratios in the depositions in some locations were used as the main input information. 370 measurements of 131I content in thyroid of townspeople and villagers, and 90 measurements of 131I concentration in milk were used for validation of the model predictions. A remarkable improvement in models performance comparing with previous inter-comparison exercise was demonstrated. Predictions of the various models were within a factor of three relative to the observations, discrepancies between the estimates of average doses to thyroid produced by most participant not exceeded a factor of ten.

Transfer of 131I from Fukushima to the Vegetation and Milk in France

“…Other parameters apart from deposition velocity were considered as default values in the equations. Indeed default parameters of ASTRAL fit well with values given by the IAEA EMRAS working group which aim to validate the 131 I ecological transfer models: the yield of grass ranging between 0.1 and 0.6 (kg fresh weight m –2 ) and the R c / Y ratio ranging between 0.5 to 1.65 . Also λ wb was chosen between 0.05 and 0.1 d –1 by this working group.…”

“…Also λ wb was chosen between 0.05 and 0.1 d –1 by this working group. In comparison with those “consensual” parameters, the velocity of iodine was highly variable (two to 3 orders of magnitude) from one model to another and also depending on the speciation in the air (particulate, gaseous, organic phases) …”

Radiation-Induced Differentiated Thyroid Cancer Is Associated with Improved Overall Survival but Not Thyroid Cancer–Specific Mortality or Disease-Free Survival

“…While there are considerable data describing outcomes for RE-induced DTC following disasters such as Chernobyl and in medical technologists, both the mechanism and dose of RE in these cohorts is different from that of patients who develop DTC following medical RE (8)(9)(10)(11). Additionally, although other studies have investigated DTC outcomes following therapeutic medical radiation, the length of follow-up has been short, and all have used DTC in the general population as the comparator group rather than individuals with RE-DTC.…”

“…The initial phase is exposure to a high-dose radiation burst of varying length and dose. The second phase is a long-term exposure to radiation secondary to contamination of drinking water and soil and subsequent food-chain contamination (9,10). The pattern of RE in the medical workplace occurs as hundreds of incidental low-dose seconds-long bursts that are not directed to a specific tissue taking place over the course of years or even decades (11).…”

Radioecological modeling of the 131I activity dynamics in different types of grass vegetation in the Chernobyl accident year

“…The materials of the Prague and Warsaw scenarios under the IAEA's EMRAS project (Krajewski et al 2008;Bartuskova et al 2009;Zvonova et al 2010;IAEA-TECDOC-16782012 were used in (Vlasov et al 2019) to generate such databases. The key conclusion made in (Vlasov et al 2019) was that the use of mutually consistent data on the rainfall in the major fallout period, the specific volumetric activities of 137 Cs in the atmosphere, and its fallout densities was expected to lead to a major decrease in the uncertainties involved in the 137 Cs and 131 I transport in the food chain and, therefore, to more accurately reconstructed internal exposure doses to the populationresided in the contaminated areas.…”