Medical Radiology and Radiation Safety. 2012. Vol. 57. No. 6. P. 26-42
RADIATION SAFETY
E.I. Tolstykh1, M.O. Degteva1, L.M. Peremyslova1, N.B. Shagina1, E.A. Shishkina1, V.A. Krivoschapov2, L.R. Anspaugh3, B.A. Napier4
Reconstruction of Long-Lived Radionuclide Intake with Diet for Techa Riverside Residents: Part 1. Strontium-90
1. Urals Research Center for Radiation Medicine, Chelyabinsk, Russia, e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it. ; 2. Southern Urals State University, Chelyabinsk, Russia; 3. University of Utah, Salt Lake City, USA; 4. Battelle Pacific Northwest National Laboratory, Richland, USA
Abstract
Purpose: Improvement of 90Sr diet intake function for residents of riverside settlements of Techa River contaminated due to releases of liquid radioactive wastes of Mayak plutonium production association (MPA) in 1949-1956. The cohorts of Techa riverside residents are studied for assessment of health radiation effects. For cohort member 90Sr was the main dose forming radionuclide. The study of MPA archive performed in 2006-2008 have shown that massive radioactive releases were started in September 1950 and not in the beginning of 1950, as it was assumed under elaboration of Techa River dosimetry system (TRDS-2000) basing on the data available. So the need to revalue the 90Sr intake function arises due to the change of “zero-point” of release time.
Material and methods: The data on 90Sr content in human body (data on in vivo measurements with whole body counter and tooth betacounter), and available data on 90Sr measurements in samples of soil, river water and cow milk were used for reconstruction of 90Sr intake function. The non-standard approach based on the solution of mathematic inverse problem (equation) was applied. The equation related the results of tooth beta-counter measurements and function of 90Sr diet intake form Muslyumovo residents was used. The Muslyumovo village is the most investigated settlement in terms of dosimetry, so it assumes as reference Techa River settlement.
Results: The total 90Sr intake level for adult Techa riverside residents changed insignificantly in comparison with TRDS-2000 estimations. The total 90Sr intake during 1950-1980 for Muslyumovo residents was estimated as 3200 kBq. In TRDS-2000 this value was similar. However, the shift of “zero-point” of releases resulted in significant changes of 90Sr intake in different calendar years. For example, for 1953-1954 the intake level increases by a factor of 5-7. For Muslyumovo residents of 1947 birth year (3-4 year old at the time of maximal releases) the total intake increases by 35 % (2400 kBq in comparison with 1800 kBq), that lead to increase in internal doses due to 90Sr, and internal dose rates in some years. The approaches to 90Sr intake reconstruction in other Techa riverside settlements are also discussed in the paper. Conclusions: Obtained values of 90Sr intakes allow to improve the individual dose estimates for Techa River cohort members, that is necessary for correct estimates of epidemiological risks of late radiation effects.
Key words: strontium-90, cesium-137, Techa River, mathematic inverse problem, radionuclide diet intake