Analysis of EPR and FISH studies of radiation doses in persons who lived in the upper reaches of the Techa River

Abstract

Waterborne radioactive releases into the Techa River from the Mayak Production Association in Russia during 1949-1956 resulted in significant doses to about 30,000 persons who lived in downstream settlements. The residents were exposed to internal and external radiation. Two methods for reconstruction of the external dose are considered in this paper, electron paramagnetic resonance (EPR) measurements of teeth, and fluorescence in situ hybridization (FISH) measurements of chromosome translocations in circulating lymphocytes. The main issue in the application of the EPR and FISH methods for reconstruction of the external dose for the Techa Riverside residents was strontium radioisotopes incorporated in teeth and bones that act as a source of confounding local exposures. In order to estimate and subtract doses from incorporated (89,90)Sr, the EPR and FISH assays were supported by measurements of (90)Sr-body burdens and estimates of (90)Sr concentrations in dental tissues by the luminescence method. The resulting dose estimates derived from EPR to FISH measurements for residents of the upper Techa River were found to be consistent: The mean values vary from 510 to 550 mGy for the villages located close to the site of radioactive release to 130-160 mGy for the more distant villages. The upper bound of individual estimates for both methods is equal to 2.2-2.3 Gy. The EPR- and FISH-based dose estimates were compared with the doses calculated for the donors using the most recent Techa River Dosimetry System (TRDS). The TRDS external dose assessments are based on the data on contamination of the Techa River floodplain, simulation of air kerma above the contaminated soil, age-dependent lifestyles and individual residence histories. For correct comparison, TRDS-based doses were calculated from two sources: external exposure from the contaminated environment and internal exposure from (137)Cs incorporated in donors' soft tissues. It is shown here that the TRDS-based absorbed doses in tooth enamel and muscle are in agreement with EPR- and FISH-based estimates within uncertainty bounds. Basically, this agreement between the estimates has confirmed the validity of external doses calculated with the TRDS.

Retrospective and emergency dosimetry in response to radiological incidents and nuclear mass-casualty events: A review

“…The 90 Sr-corrected doses were split into four groups, depending on the distance from the release site: group I included the residents of Metlino located at 7 km from the site while group IV represented the residents of Ibragimovo and Isaevo located at 54 and 60 km from the release site, respectively. The first finding was that EPR doses were comparable to the corresponding FISH-based estimates within the same groups (Degteva et al, 2005 andDegteva et al, 2015). This allowed use of the both EPR and FISH dose estimates for the comparison with the dose estimates produced by the TRDS.…”

“…EPR tooth dosimetry research started to grow rapidly after the Chernobyl accident in 1986 (Aldrich and Pass, 1988, Shimano et al, 1989and Ikeya and Ishii, 1989, which resulted in maturation of the EPR technique with tooth enamel. The technique has been verified through several intercomparisons (Chumak et al, 1996, Wieser et al, 2000a and was applied for dose reconstruction of A-bomb victims (Ikeya et al, 1984 andNakamura et al, 1998), Chernobyl liquidators , the population in territories contaminated due to the Chernobyl accident (Skvortzov et al, 1995, Skvortzov et al, 2000, Ivannikov et al, 1997, Ivannikov et al, 2004band Ivannikov et al, 2014, residents near the Semipalatinsk Nuclear Test Site (SNTS, Kazakhstan) , Zhumadilov et al, 2009, Zhumadilov et al, 2011a, Zhumadilov et al, 2011b, Zhumadilov et al, 2013Ivannikov et al, 2002, Pivovarov et al, 2002and Sholom et al, 2007a, and the inhabitants of the Techa River basin affected by the operation of the Mayak Production Association , Degteva et al, 2005, Degteva et al, 2015.…”

“…As applications in retrospective dosimetry progressed (e.g., Ishii et al, 1990, Serezhenkov et al, 1992, Romanyukha et al, 1994, Chumak et al, 1999, so too did technique development. EPR of teeth is now a well-established method for evaluating absorbed doses to individuals under many circumstances (Egersdorfer et al, 1996, Pass, 1997, IAEA, 2002, Fattibene and Callens, 2010, Ainsbury et al, 2011, Sullivan et al, 2013and Degteva et al, 2015. The method has been tested against biodosimetry methods (e.g., Nakamura et al, 1998and Khvostunov et al, 2015 and conventional dosimeters (e.g., Romanyukha et al, 2000b), and in multiple inter-laboratory comparisons (e.g., Chumak et al, 1996, Wieser et al, 2000a.…”

“…The determined values were compared with doses reconstructed using the most-recent Techa River Dosimetry System (TRDS) (Degteva et al, 2015). The main issue in EPR dosimetry with teeth for the Techa River residents is related to strontium radioisotopes incorporated in teeth during enamel formation .…”

“…In the first case, the EPR technique estimates the dose to an individual, which can be used directly in epidemiological and other radiation-related studies. Also, EPR dosimetry may be used to provide benchmark values of dose that check the analytical methods of dose reconstruction Degteva et al, 2015).…”