Reconstruction of Long-Lived Radionuclide Intakes for Techa Riverside Residents: Strontium-90

Abstract

Releases of radioactive materials from the Mayak Production Association in 1949-1956 resulted in contamination of the Techa River; a nuclide of major interest was 90Sr, which downstream residents consumed with water from the river and with milk contaminated by cows' consumption of river water and contaminated pasture. Over the years, several reconstructions of dose have been performed for the approximately 30,000 persons who make up the Extended Techa River Cohort. The purpose of the study described here was to derive a revised reference-90Sr-intake function for the members of this cohort. The revision was necessary because recently discovered data have provided a more accurate description of the time course of the releases, and more is now known about the importance of the pasture grass-cow-milk pathway for the members of this cohort. The fundamental basis for the derivation of the reference-90Sr-intake function remains the same: thousands of measurements of 90Sr content in bone with a special whole-body counter, thousands of measurements of beta-activity of front teeth with a special tooth-beta counter, and a variety of other measurements, including post mortem measurements of 90Sr in bone, measurements of 90Sr in cow's milk, and measurements of beta activity in human excreta. Results of the new analyses are that the major intake started in September 1950 and peaked somewhat later than originally postulated. However, the total intake for adult residents has not changed significantly. For children of some birth years, the intake and incorporation of Sr in bone tissue have changed substantially.

Leukaemia incidence in the Techa River Cohort: 1953–2007

“…Recent improvements are described in (Shagina et al , 2003; Degteva et al , 2007, 2009; Tolstykh et al , 2011; Degteva et al , 2012; Shagina et al , 2012a, 2012b). …”

“…It is one of few human populations protracted strontium exposure, a radionuclide which concentrates in the bone and is thus of great relevance for leukaemia studies. The TRC members were exposed to external γ -radiation exposure from contaminated river sediments and flood plain soil and internal exposure from radionuclides including strontium 89 , strontium 90 , and caesium 137 from the consumption of contaminated water, milk, and food products following the release of radioactive waste into the River by the Mayak Radiochemical Plant between 1949 and 1956 (Akleyev et al , 1995; Degteva et al , 2006; Tolstykh et al , 2011). …”

In utero exposure to radiation and haematological malignancies: pooled analysis of Southern Urals cohorts

“…The model published in the International Commission on Radiological Protection's Publication 88 was used to calculate the in utero doses from cesium (International Commission on Radiological Protection (ICRP), 2001). Estimates of dietary intake of strontium-90 and cesium-137 among adult Techa River residents (Tolstykh et al , 2011, 2013), adjusted for increased food consumption by pregnant women (Shagina et al , 2015a), were also used. External in utero exposure during pregnancy was estimated using the Techa River Dosimetry System 2009, using maternal uterine exposure as a surrogate measure.…”

DoReMi workshop on multidisciplinary approaches to evaluating cancer risks associated with low-dose internal contamination

“…For instance, the quantity of administrated 131-Iodine is well documented in the medical cohorts, although as mentioned previously, the radiation dose to the target organ (thyroid) is very high. Much effort has gone into the evaluation of the exposure of the Techa River cohort members; additional work to reduce uncertainties in the organ doses reconstructed for this cohort is currently in progress (Tolstykh et al, 2011). Individual doses to the thyroid from the radioactive isotopes of iodine as well as the doses to other organs outside the thyroid that were reconstructed based upon individual thyroid activity measurements are also available for the members of the Bel-Am and Ukr-Am cohorts.…”