Dosimetry for members of the extended Techa River cohort
The undersigned and colleagues are creators and a critic of the Techa River Dosimetry System-2000 (TRDS-2000), which was the subject of a recent article by Balonov et al. This article presented a consensus on a review of the TRDS-2000 achieved following a workshop in December 2003. The TRDS-2000 was used to derive risk coefficients for members of an unselected general population exposed to moderate doses of radiation at low dose rates on the Techa River in the 1950s. Because it is now more than two years since the workshop, a significant number of events have transpired, and the purpose of this letter is to inform readers of current developments. As noted in Balonov et al., much of the concern about the dosimetric and epidemiologic investigation of the Extended Techa River Cohort was heightened by a preliminary derivation of risk estimates that were higher than those derived from study of the survivors of the atomic bombings in Japan, but not significantly different. Similar results showing risks for leukemia and solid cancers about 50% higher than those in the Japanese survivors have now been published. These unexpected results have raised the issue of the validity of the doses being calculated with the TRDS-2000. Much of the honest differences of opinion among the undersigned about the TRDS-2000 is concerned with the accuracy and precision of the releases to the Techa River during the 1949-1951 period. Balonov et al. recommended many steps to investigate further information available on the releases, and to take other steps to resolve differences in opinion. As noted by Balonov et al., one of the more promising was a proposed study (with funding requested from the International Science and Technology Center) for the undersigned to work together on the ?source-term problem? along with additional Russian experts from the Institute of Plant and Animal Ecology, Ekaterinburg, and the Zababakhin Institute of Technical Physics, Snezhinsk. We are pleased that the study has now been funded, and there has been a major discovery that may profoundly affect the accuracy and credibility of the Techa River source term. Important records dated from 1949?1956 have been found in the Mayak archives and include detailed data on, e.g., irradiation times of uranium blocks in the reactors, the cooling time of the blocks, and information on waste-storage equipment and processing. The latter will be important in determining the age and fractionation of fission products discharged. Efforts are underway to review these documents and to make important data available to the international community. Efforts are ongoing to make historic documents more widely available to the scientific community through re-publication in Radiation Safety Problems. Other recommendations of Balonov et al. are being implemented. Many efforts are being undertaken to validate estimates of internal and external doses; the results of past efforts have been published in Degteva et al. Additional efforts are underway as part of a cooperative Russian-European Commission program. An internationally coordinated effort is underway to perform a complete analysis of uncertainty for the estimates of dose and how the uncertainty in individual doses translates into derivations of risk coefficients. Many other improvements have been made or are being made in the TRDS; these are too numerous to describe here, but current accomplishments and plans for future work have been described in Degteva et al. Thus, the recommendations of Balonov et al. for improvements in dosimetry are being implemented with enthusiasm through joint activities of Russian, American, and European colleagues. We believe that the resulting dosimetry system will be credible and can be validated against a large volume of data on environmental measurements and of radionuclide-body burdens in people.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 893665
- Report Number(s):
- PNNL-SA-52204; HD2006300; TRN: US0606037
- Journal Information:
- Health Physics, 91(4):393-394, Journal Name: Health Physics, 91(4):393-394
- Country of Publication:
- United States
- Language:
- English
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