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Waterborne releases to the Techa River from the Mayak plutonium facility in Russia during 1949-1956 resulted in significant doses to persons living downstream. The dosimetry system Techa River Dosimetry System-2016D has been developed, which provides individual doses of external and internal exposure for the members of the Techa River cohort and other persons who were exposed to releases of radioactive material to the Southern Urals. The results of computation of individual doses absorbed in red bone marrow and extraskeletal tissues for the Techa River cohort members (29,647 persons) are presented, which are based on residence histories on the contaminated Techa River and the East Urals Radioactive Trace, which was formed in 1957 as a result of the Kyshtym Accident. Available Sr body-burden measurements and available information on individual household locations have been used for refinement of individual dose estimates. Techa River Dosimetry System-2016D-based dose estimates will be used for verification of risk of low-dose-rate effects of ionizing radiation in the Techa River cohort.

Release of liquid radioactive waste into the Techa River from the Mayak Production Association during 1949-1956 resulted in a significant exposure of about 30000 people who lived in downstream settlements. The residents were exposed to internal and external radiation. The article discusses the capability of two methods that were used 50 years after the termination of radioactive discharges for the dose reconstruction, namely EPR measurements of tooth enamel, and FISH measurements of stable chromosome aberrations in circulating lymphocytes. The Main issue in the application of these methods for the dose reconstruction was local irradiation from strontium radioisotopes incorporated in teeth and bones. The EPR and FISH assays were supported by measurements of the 90Sr content in the skeleton and teeth in order to estimate and subtract internal doses from incorporated 89, 90Sr. The resulting dose estimates obtained from EPR and FISH mea- surements were found to be consistent The settlement-averaged values in the upper-Techa Region varied from 550-570 mGy to 130-160 mGy and showed a reduction with the distance from the release site. The EPR- and FISH-based dose estimates were in agreement with the doses calculated with the dosimetry system TRDS that uses data on radionuclide contamination of the Techa River floodplain and individual residential histories.

Analysis of recently available archive materials regarding the liquid radioactive waste storage and reprocessing at the "Mayak" Production Association in 1949-1956 has led to a more accurate reconstruction of radionuclide releases into the Techa River. Radionuclide concentrations in the Techa River water, bottom sediments and floodplain soils in 1949-1951 were reconstructed with the use of a purposely-developed Techa River model. Model calculations agree with the measurements of the specific activity in the river water and bottom sediments conducted since 1951. The model output for the (90)Sr concentration in the river water shows a good agreement with the retrospective estimates derived from (90)Sr measurements in teeth and the whole body of the Techa riverside residents. Modeled (137)Cs-contamination of the floodplain shows agreement with the values reconstructed from (137)Cs measurements in the floodplain soils obtained in later years. Reconstructed contamination levels by radionuclides in the Techa River water and floodplain are being used to refine internal and external doses and risk estimates of late effects in the population chronically exposed to radiation.

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.

A biokinetic model for strontium (Sr) for the pregnant woman and fetus (Sr-PWF model) has been developed for use in the quantification of doses from internal radiation exposures following maternal ingestion of Sr radioisotopes before or during pregnancy. The model relates in particular to the population of the Techa River villages exposed to significant amounts of ingested Sr radioisotopes as a result of releases of liquid radioactive wastes from the Mayak plutonium production facility (Russia) in the early 1950s. The biokinetic model for Sr metabolism in the pregnant woman was based on a biokinetic model for the adult female modified to account for changes in mineral metabolism during pregnancy. The model for non-pregnant females of all ages was developed earlier with the use of extensive data on (90)Sr-body measurements in the Techa Riverside residents. To determine changes in model parameter values to take account of changing mineral metabolism during pregnancy, data from longitudinal studies of calcium homeostasis during human pregnancy were analysed and applied. Exchanges between maternal and fetal circulations and retention in fetal skeleton and soft tissues were modelled as adaptations of previously published models, taking account of data on Sr and calcium (Ca) metabolism obtained in Russia (Southern Urals and Moscow) relating to dietary calcium intakes, calcium contents in maternal and fetal skeletons and strontium transfer to the fetus. The model was validated using independent data on (90)Sr in the fetal skeleton from global fallout as well as unique data on (90)Sr-body burden in mothers and their still-born children for Techa River residents. While the Sr-PWF model has been developed specifically for ingestion of Sr isotopes by Techa River residents, it is also more widely applicable to maternal ingestion of Sr radioisotopes at different times before and during pregnancy and different ages of pregnant women in a general population.

This paper presents a biokinetic model for strontium metabolism in the lactating woman and transfer to breast milk for members of Techa River communities exposed as a result of discharges of liquid radioactive wastes from the Mayak plutonium production facility (Russia) in the early 1950s. This model was based on that developed for the International Commission for Radiological Protection with modifications to account for population specific features of breastfeeding and maternal bone mineral metabolism. The model is based on a biokinetic model for the adult female with allowances made for changes in mineral metabolism during periods of exclusive and partial breast-feeding. The model for females of all ages was developed earlier from extensive data on (90)Sr-body measurements for Techa Riverside residents. Measurements of (90)Sr concentrations in the maternal skeleton and breast milk obtained in the1960s during monitoring of global fallout in the Southern Urals region were used for evaluation of strontium transfer to breast and breast milk. The model was validated with independent data from studies of global fallout in Canada and measurements of (90)Sr body-burden in women living in the Techa River villages who were breastfeeding during maximum (90)Sr-dietary intakes. The model will be used in evaluations of the intake of strontium radioisotopes in breast milk by children born in Techa River villages during the radioactive releases and quantification of (90)Sr retention in the maternal skeleton.

The European Union's SOLO (Epidemiological Studies of Exposed Southern Urals Populations) project aims to improve understanding of cancer risks associated with chronic in utero radiation exposure. A comprehensive series of hybrid computational fetal phantoms was previously developed at the University of Florida in order to provide the SOLO project with the capability of computationally simulating and quantifying radiation exposures to individual fetal bones and soft tissue organs. To improve harmonization between the SOLO fetal biokinetic models and the computational phantoms, a subset of those phantoms was systematically modified to create a novel series of phantoms matching anatomical data representing Russian fetal biometry in the Southern Urals. Using previously established modeling techniques, eight computational Urals-based phantoms aged 8, 12, 18, 22, 26, 30, 34, and 38 weeks post-conception were constructed to match appropriate age-dependent femur lengths, biparietal diameters, individual bone masses and whole-body masses. Bone and soft tissue organ mass differences between the common ages of the subset of UF phantom series and the Urals-based phantom series illustrated the need for improved understanding of fetal bone densities as a critical parameter of computational phantom development. In anticipation for SOLO radiation dosimetry studies involving the developing fetus and pregnant female, the completed phantom series was successfully converted to a cuboidal voxel format easily interpreted by radiation transport software.

One of the many objectives of the European Union's SOLO (Epidemiological Studies of Exposed Southern Urals Populations) project is to quantify the radiation dose-response following chronic in utero exposures to ionizing radiation. The project is presently conducting a pooled analysis of two cohorts of individuals born to exposed mothers-the Techa River Offspring Cohort (TROC) and the Ozyorsk Offspring Cohort (OOC). The TROC includes the offspring of mothers with external exposures to contaminated riverbanks and internal ingestions of (89)Sr, (90)Sr/(90)Y, and (137)Cs/(137m)Ba, while the OOC includes the offspring of mothers with external exposures seen within the Mayak plutonium production facilities and internal inhalation of (239)Pu and possibly (131)I. In the present study, a newly created Urals-based series of fetal and maternal models is employed to assess S values for all seven radionuclides. Among all fetal ages, S values ranged in magnitude from 10(-14) to 10(-10) Gy per Bq-s for fetal source organs and from 10(-18) to 10(-14) Gy per Bq-s from maternal source organs, depending upon particle type, particle energy, and fetal age. For a given radionuclide and fetal age, S values for fetal source organs were approximately two orders of magnitude higher than for maternal source organs. Little variation in S values was observed among fetal source organs, while variations of over 100 % with respect to the mean were observed for maternal source organs near the fetus. S value variations from maternal cross-fire were highly dependent on fetal position and separation distance from the maternal source organ. These radionuclide S values have been coupled with biokinetic models for use in cohort dose assessment within the SOLO project.

A biokinetic model for strontium in humans is necessary for quantification of internal doses due to strontium radioisotopes. The ICRP-recommended biokinetic model for strontium has limitations for use in a population study, because it is not gender specific and does not cover all age ranges. The extensive Techa River data set on (90)Sr in humans (tens of thousands of measurements) is a unique source of data on long-term strontium retention for men and women of all ages at intake. These, as well as published data, were used for evaluation of age- and gender-specific parameters for a new compartment biokinetic model for strontium (Sr-AGe model). The Sr-AGe model has a similar structure to the ICRP model for the alkaline earth elements. The following parameters were mainly re-evaluated: gastrointestinal absorption and parameters related to the processes of bone formation and resorption defining calcium and strontium transfers in skeletal compartments. The Sr-AGe model satisfactorily describes available data sets on strontium retention for different kinds of intake (dietary and intravenous) at different ages (0-80 years old) and demonstrates good agreement with data sets for different ethnic groups. The Sr-AGe model can be used for dose assessment in epidemiological studies of general populations exposed to ingested strontium radioisotopes.

The unique contamination of the Techa River (Southern Urals, Russia) in the 1950s by long-lived (90)Sr allows investigation of the accumulation of bone-seeking elements in humans. This study is based on information compiled at the Urals Research Center for Radiation Medicine (Chelyabinsk, Russia) over a long period of time. It includes the results of in vivo measurements of (90)Sr-body burden with a whole body counter (WBC), data on personal medical examinations and residence and family histories. Data on 185 women from two Techa riverside villages Muslyumovo and Brodokalmak were selected. The settlements differ in terms of (90)Sr diet intake (higher in Muslyumovo than in Brodokalmak) and ethnicity (residents were mainly Slavs in Brodokalmak and Turkic in Muslyumovo). Results of a total of 555 WBC measurements performed in 1974-1997 were available for the women studied; maximum measured values reached 40 kBq/body. The women from each settlement were subdivided into three groups according to their childbearing history: pregnancy and lactation occurred (1) during the period of maximal (90)Sr intake (1950-1951); (2) after the period of maximal intake and (3) before this period or women who were childless. An increase was found in accumulation of (90)Sr in maternal skeleton during pregnancy and lactation (group 1) by a factor of 1.5-2 in comparison with non-pregnant, non-lactating women. This result was found in both Muslyumovo and Brodokalmak samples. An increase in accumulation of toxic elements in pregnant/lactating women is associated with increased radiation/toxic doses and risk for the women's health.

Fluorescent in situ hybridisation analysis of stable translocations was performed for 26 residents living along the Techa River (Russia), who were predominantly (95%) exposed to ingested strontium radioisotopes ((89)Sr and (90)Sr) resulting in exposure of their red bone marrow (RBM). Analysis was conducted at the Urals Research Center for Radiation Medicine, Public Health England and Leiden University Medical Center. Each laboratory scored 1000 cells per donor, which resulted in ∼1000 genome equivalents (GE) per donor. The age-dependent spontaneous level of translocations for each donor was evaluated on the basis of data published by Sigurdson et al. (International study of factors affecting human chromosome. Mutat. Res. 2008;652: :112-121). Reconstruction of doses was performed with the 'Techa River Dosimetry System' developed in 2009. In the studied donors, the range of individual cumulated RBM dose was from 0.3 to 3.7 Gy. Analysis of the yield of stable translocations dependent on the individual RBM dose from (89,90)Sr showed a linear dose-response relationship of 0.007 ± 0.002 translocation/GE cell/Gy (R = 0.61, p = 0.001). This set of results was in a good agreement with the previous data reported for 18 donors by Vozilova et al. (Preliminary FISH-based assessment of external dose for residents exposed on the Techa River., (© The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

This paper presents the results of a cytogenetic study conducted among residents of the Techa Riverside communities (Southern Urals, Russia) exposed in the early 1950s as a result of releases of liquid radioactive wastes from the Mayak plutonium-production facility. The study was performed 50-60 years after the beginning of the exposure for those individuals who were predominantly exposed to strontium radioisotopes ((89,90)Sr) through drinking contaminated river water and consumption of local foodstuff. Standard cytogenetic methods were used for evaluation of the frequency of unstable chromosome aberrations in exposed persons as well as in persons from the control group who were of similar age and sex, living in similar socio-economic conditions in non-contaminated territories of the Southern Urals. The exposure doses were reconstructed for the studied donors using the Techa River Dosimetry System developed in 2009. The doses of internal exposure from ingested radionuclides were evaluated using individual or family in vivo measurements of (90)Sr-body burden. Individual cumulative absorbed doses in red bone marrow (RBM) in the studied persons varied in the range of 0.01-4.4Gy. A significantly higher level of unstable chromosome aberrations (UCA) in T-cells was observed in the group of exposed individuals as compared to control group. The highest UCA level was detected in the individuals who were suspected of having chronic radiation syndrome., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Radioactive contamination of the Techa River (Southern Urals, Russia) occurred from 1949-1956 due to routine and accidental releases of liquid radioactive wastes from the Mayak Production Association. The long-lived radionuclides in the releases were Sr and Cs. Contamination of the components of the Techa River system resulted in chronic external and internal exposure of about 30,000 residents of riverside villages. Data on radionuclide intake with diet are used to estimate internal dose in the Techa River Dosimetry System (TRDS), which was elaborated for the assessment of radiogenic risk for Techa Riverside residents. The Sr intake function was recently improved, taking into account the recently available archival data on radionuclide releases and in-depth analysis of the extensive data on Sr measurements in Techa Riverside residents. The main purpose of this paper is to evaluate the dietary intake of Cs by Techa Riverside residents. The Cs intake with river water used for drinking was reconstructed on the basis of the Sr intake-function and the concentration ratio Cs-to-Sr in river water. Intake via Cs transfer from floodplain soil to grass and cows' milk was evaluated for the first time. As a result, the maximal Cs intake level was indicated near the site of releases in upper-Techa River settlements (8,000-9,000 kBq). For villages located on the lower Techa River, the Cs intake was significantly less (down to 300 kBq). Cows' milk was the main source of Cs in diet in the upper-Techa River region.

More accurate reconstruction of the radioactive contamination of the Techa River system in 1949-1951 has been made on the basis of refined data on the amounts and the rate of discharge of radionuclides into the Techa River from the Mayak Production Association; this has led to the development of a modified Techa River model that describes the transport of radionuclides through the up-river ponds and along the Techa River and deposition of radionuclides in the river-bottom sediments and flooded areas. The refined Techa River source-term data define more precisely the time-dependent rates of release and radionuclide composition of the releases that occurred during 1949-1951. The Techa River model takes into account the time-dependent characteristics of the releases and considers (a) the transport of radionuclides adsorbed on solid particles originally contained in the discharges or originating in the up-river ponds as a result of stirring up of contaminated bottom sediments and (b) the transport of radionuclides in soluble form. The output of the Techa River model provides concentrations of all source-term radionuclides in the river water, bottom sediments, and floodplain soils at different distances from the site of radioactive releases for the period of major contamination in 1950-1951. The outputs of the model show good agreement with historical measurements of water and sediment contamination. In addition, the river-model output for (90)Sr concentration in the river water is harmonized with retrospective estimates derived from the measurements of (90)Sr in the residents of the Techa Riverside villages. Modeled contamination of the floodplain soils by (137)Cs is shown to be in agreement with the values reconstructed from late measurements of this radionuclide. Reconstructed estimates of the Techa River contamination are being used for the quantification of internal and external doses received by residents of the Techa Riverside communities.

The rate of cortical bone resorption was assessed from long-term in vivo measurements of (90)Sr content in the skeleton for men aged 50-80 years and for women 0-30 years after menopause. Measurements of (90)Sr were conducted with a whole body counter (WBC) for residents of the Techa Riverside communities (Southern Urals, Russia), who ingested large amounts of (90)Sr as a result of releases of liquid radioactive wastes into the river from the Mayak plutonium facility in early 1950s. The results of this study showed an increase in the rate of cortical bone resorption in both men and women, as based on the use of accidentally ingested (90)Sr as a tracer for bone metabolism. In men there was a continuous gradual increase in the rate of cortical bone resorption after 55 years from 2.8 to 4.5%/year by the age of 75 years. In women, there was a doubled increase in the rate of cortical bone resorption after menopause of up to 6%/year; then the rate remained unchanged for 10-12 years with a subsequent gradual decline down to 5-5.5%/year. Comparison of the rate of cortical bone resorption in men and women older than 55 years showed that women expressed significantly higher levels of cortical bone resorption., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

This paper presents the results of a feasibility cytogenetic study using the fluorescence in situ hybridization (FISH) translocation assay for residents of villages located on the Techa River (Southern Urals, Russia) contaminated with liquid radioactive wastes from the Mayak plutonium facility in 1949-1956. The study was conducted with two groups of donors that differed in their main pathways of exposure. The first group comprised 18 residents of the middle Techa region who were exposed predominantly from ingestion of radionuclides (mostly (89,90)Sr) via the river water and local foodstuffs. The second group included 20 residents of Metlino, the closest village to the site of releases, who were exposed to external γ radiation from the contaminated river bank and exposed internally from dietary intake of radionuclides. A significant linear dependence between the radiation-induced translocation frequency and individual red bone marrow dose from incorporated (89,90)Sr, calculated with the Techa River Dosimetry System (TRDS), was found in the first group of donors. This allowed us to take the contribution of (89,90)Sr to the total radiation-induced translocation frequency into account for the second group of donors and to analyze translocations resulting from external γ-ray exposure. Individual doses from external exposure derived from the corrected translocation frequency for the second group of donors (Metlino residents), using a linear dose-response coefficient of 0.015 translocation/cell/Gy recommended by Edwards et al. in 2005, were shown to vary up to 2.1 Gy, with an average value of 0.48 Gy, which was in agreement with TRDS-based external dose estimates for Metlino residents.

The Mayak Production Association was the first site for the production of weapons-grade plutonium in Russia. Early operations led to the waterborne release of radioactive materials into the small Techa River. Residents living downstream used river water for drinking and other purposes. The releases and subsequent flooding resulted in deposition of sediments along the shoreline and on floodplain soil. Primary routes of exposure were external dose from the deposited sediments and ingestion of 90Sr and other radionuclides. Study of the Techa River Cohort has revealed an increased incidence of leukemia and solid cancers. Epidemiologic studies are supported by extensive dose-reconstruction activities that have led to various versions of a Techa River Dosimetry System (TRDS). The correctness of the TRDS has been challenged by the allegation that releases of short-lived radionuclides were much larger than those used in the TRDS. Although the dosimetry system depends more upon measurements of 90Sr in humans and additional measurements of radionuclides and of exposure rates in the environment, a major activity has been undertaken to define more precisely the time-dependent rates of release and their radionuclide composition. The major releases occurred during 1950-1951 in the form of routine releases and major accidental releases. The reevaluated amount of total release is 114 PBq, about half of which was from accidents that occurred in late 1951. The time-dependent composition of the radionuclides released has also been reevaluated. The improved understanding presented in this paper is possible because of access to many documents not previously available.

The Mayak Production Association released large amounts of (90)Sr into the Techa River (Southern Urals, Russia) with peak amounts in 1950-1951. Techa Riverside residents ingested an average of about 3,000 kBq of (90)Sr. The (90)Sr-body burden of approximately 15,000 individuals has been measured in the Urals Research Center for Radiation Medicine in 1974-1997 with use of a special whole-body counter (WBC). Strontium-90 had mainly deposited in the cortical part of the skeleton by 25 years following intake, and (90)Sr elimination occurs as a result of cortical bone resorption. The effect of (90)Sr-radiation exposure on the rate of cortical bone resorption was studied. Data on 2,022 WBC measurements were selected for 207 adult persons, who were measured three or more times before they were 50-55 years old. The individual-resorption rates were calculated with the rate of strontium recirculation evaluated as 0.0018 year(-1). Individual absorbed doses in red bone marrow (RBM) and bone surface (BS) were also calculated. Statistically significant negative relationships of cortical bone resorption rate were discovered related to (90)Sr-body burden and dose absorbed in the RBM or the BS. The response appears to have a threshold of about 1.5-Gy RBM dose. The radiation-induced decrease in bone resorption rate may not be significant in terms of health. However, a decrease in bone remodeling rate can be among several causes of an increased level of degenerative dystrophic bone pathology in exposed persons.

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.

This paper presents the results of a replication study performed to investigate earlier Soviet studies conducted between 1974 and 1991 that showed immunological and reproductive effects of long-term low-level exposure of rats to radiofrequency (RF) electromagnetic fields. The early studies were used, in part, for developing exposure standards for the USSR population and thus it was necessary to confirm the Russian findings. In the present study, the conditions of RF exposure were made as similar as possible to those in the earlier experiments: Wistar rats were exposed in the far field to 2450 MHz continuous wave RF fields with an incident power density in the cages of 5 W/m² for 7 h/day, 5 days/week for a total of 30 days, resulting in a whole-body SAR of 0.16 W/kg. Effects of the exposure on immunological parameters in the brain and liver of rats were evaluated using the complement fixation test (CFT), as in the original studies, and an additional test, the more modern ELISA test. Our results, using CFT and ELISA, partly confirmed the findings of the early studies and indicated possible effects from non-thermal RF exposure on autoimmune processes. The RF exposure resulted in minor increases in formation of antibodies in brain tissue extract and the exposure did not appear to be pathological. In addition, a study was conducted to replicate a previous Soviet study on effects from the injection of blood serum from RF-exposed rats on pregnancy and foetal and offspring development of rats, using a similar animal model and protocol. Our results showed the same general trends as the earlier study, suggesting possible adverse effects of the blood serum from exposed rats on pregnancy and foetal development of intact rats, however, application of these results in developing exposure standards is limited., (Copyright © 2010 Wiley-Liss, Inc.)

Operation of "Mayak" plutonium production complex resulted in radioactive contamination of the part of Chelyabinsk Region in 1950-60s. Significant gas-aerosol emissions of 1311 occurred since 1948; in 1957, a radiation accident resulted in 90Sr contamination of large territories. This paper presents comparison of bone mineral density of persons lived on territories with different levels of soil 90Sr-contamination with a control group. It was found that in 1970-1975 the bone mineral density, estimated from mineral content in bone samples, in residents of contaminated areas born in 1936-1952 was significantly lower compared with the control group. For persons born in 1880-1935 such differences were not found. It was shown that the decrease in bone mineral density was not related to 90Sr exposure of osteogenic cells in the dose range from 0.1 to 1300 mGy: the coefficient of correlation between individual 90Sr-doses and bone mineral contents was not significant. The decrease in bone mineral density of persons born in 1936-1952 could be associated with exposure of thyroid and parathyroid glands (systemic regulators of calcium turnover) by 131I from gas-aerosol emissions from "Mayak". Maximum gas-aerosol emissions occurred in 1948-1954 and coincided with growth and development of thyroid gland, characterizing by intensive accumulation of 131I, and with growth and maturation of the skeleton of persons born in these calendar years.

The river Iset belongs to the Techa-Iset-Tobol-Irtysh-Ob system contaminated by liquid radioactive wastes from Mayak plutonium facility in 1949-1956. This study represents the first retrospective analysis of postmortem measurements of 90Sr in bones from residents of the Iset riverside settlements in 1960-1982. It was shown that 90Sr concentration in bones of residents lived in settlements located downstream from the Techa river mouth (Shadrinsk, Isetskoye, Yalutorovsk) was 5 times higher than average 90Sr concentration in bones of the Russian residents. There was not statistically significant difference in accumulated 90Sr in bones between residents of the considered Iset' settlements indicating similar levels of 90Sr ingestion. Dietary 90Sr intake was reconstructed from the measurements of the radionuclide in bones. Total 90Sr dietary intake in 1950-1975 was 68 kBq; and 90% of the intake occurred in 1950-1961. In 1960s, 90Sr-contamination of the diet in settlements located downstream from the Techa river mouth was mostly (by 70%) due to global fallouts. Absorbed dose in the red bone marrow cumulated over 25 years of exposure was equal to 14 (4.7-42) mGy.

Bone mineral content in rib samples from Ural region residents was analyzed depending on donors' gender, age and year of birth. Bone mineral content, that reflects the mineral density, was estimated as gram of minerals per 1 kg of wet bone mass. The period of sampling and measurements covered 1958-1988, the age of donors ranged from newborn to 99 years, birth years varied from 1872 to 1984, and the total number of samples was equal to 4685. A decrease in bone mineral density during 1958-1988 period was found in groups of close ages but different years of birth indicating an existence of the secular trend. For people born before 1920, the trend was insignificant. For people born in later years, a continuous decrease in bone mineral content was observed in groups of the same ages with an average rate of 3 g/kg per year, which is about 1% per year. Longitudinal and cross-sectional studies of bone mineral density provide different estimates of age dependent rate of bone mineral loss, and these values may differ by a factor of two. Different generations, i.e. people born in different periods of the XX century, have age-dependent features of bone mineral density specific for their groups.

Mobile communications provides a new source of electromagnetic exposure for almost the whole population of the Russian Federation. For the first time in the history of civilization the brain of mobile phone users was exposed to localized radiofrequency (RF) electromagnetic fields (EMF). Population exposure from the base stations is also considered to be specific. However, existing standards for limiting the exposure do not account for this special EMF source and may not ensure the absence of health effects. There was a need for reliable information that would extend databases used for development of new standards. As recommended by the World Health Organization an additional experiment was performed under the supervision of foreign experts, which showed changes in autoimmune status in rats after long-term low-level RF EMF exposure with an incident power density of 500 microW/cm2.

The paper presents the summary and the analysis of the results from a long-term monitoring of 90Sr specific activity in water of the lentic lakes Uruskul, L. Ighish, Kuyanysh and Travyanoye situated in Chelyabinsk Oblast on the East-Urals Radioactive Trace which was formed due to the 1957 accident at the Mayak PA. The data of measurements conducted over a 50-year period were approximated based on a function representing a sum of two (or three) exponents. The results of the analysis allowed us to study the peculiarities of reduction in the specific activity of 90Sr in the lakes of interest, and to obtain prognostic assessment of the development of the radioecological situation in these water reservoirs for the time period up to 2017. Presented in the paper are also data on the current levels of 90Sr and 137Cs specific activity in water of the lakes Uruskul, L. and S. Ighish, Kuyanysh, Travyanoye and Shablish. The estimates of the current reserves of these radionuclides are provided. Was shown that these lakes can be returned to the production use.

The Techa River (Southern Urals, Russia) was contaminated as a result of radioactive releases by the Mayak plutonium production facility during 1949-1956. The persons born after the onset of the contamination have been identified as the "Techa River Offspring Cohort" (TROC). The TROC has the potential to provide direct data on health effects in progeny that resulted from exposure of a general parent population to chronic radiation. The purpose of the present investigation is the estimation of (90)Sr intake from breast milk and river water in the period from birth to 6 months of life, necessary for an infant dose calculation. The investigation is based on all available data concerning radioactive contamination due to global fallouts and Mayak releases in the Southern Urals where extensive radiometric and radiochemical investigations of human tissues and environmental samples were conducted during the second half of the twentieth century. The strontium transfer factor from mother's daily diet to breast milk was estimated as 0.05 (0.01-0.13) d L(-1). Based on this transfer factor and data on (90)Sr water contamination, the average total (90)Sr intake for an infant born in the middle Techa River region was found to be equal to 60-80 kBq in 1950-1951. For the same period, calculations of (90)Sr intake using ICRP models gave values of 70-100 kBq. From 1952 onwards, the differences in intakes calculated using the two approaches increased, reaching a factor of 2-3 in 1953. The Techa River data provide the basis for improving and adapting the ICRP models for application to Techa River-specific population.

A methodology was developed for reduction of uncertainties in estimates of internal dose for residents of the Techa Riverside communities, who were exposed as a result of releases of radionuclides from the Mayak plutonium production facility in 1949-56. The 'Techa River Dosimetry System' (TRDS) was specifically elaborated for reconstruction of doses. A preliminary analysis of uncertainty for doses estimated using the current version of the TRDS showed large ranges in the uncertainty of internal absorbed dose and led to suggestions of methods to reduce uncertainties. The new methodological approaches described in this paper will allow for significant reduction of uncertainties of 90Sr-dose. The major sources of reduction are: making use of individual measured values of 90Sr and through development of a Household Registry to associate unmeasured persons with measured persons living in the same household(s).

Reliable estimates of tissue doses to individuals exposed as a result of radioactive releases to the Techa River are essential prerequisites for epidemiological analyses. This paper describes progress made in collaborative studies, sponsored by the European Union, between the Urals Research Center for Radiation Medicine and the UK Health Protection Agency to provide dose estimates to Techa River populations following in utero exposures and infant exposures resulting from breast-feeding. Studies have concentrated on the assessment of internal doses from 90Sr as the main contributor to internal doses to the Techa River populations.

The operation of the Mayak Production Association in the Southern Urals region of Russia, resulted in releases of large amounts of radioactive effluent into the Techa River during the period 1949-1956. The residents of the riverside communities were thus exposed to both external radiation, and internal radiation following ingestion of contaminated water and foodstuffs. One of the most important radionuclides for internal exposure was 90Sr. This paper gives a brief overview of the models provided by International Commission on Radiological Protection (ICRP), which are of interest for assessing internal doses from 90Sr. The application of these models to the calculation of red bone marrow doses for the fetus and infant from 90Sr intakes by the mother and the infant is illustrated by an example. A hypothetical individual born in 1951 is used as an example for dose calculations. The following doses due to intakes of 90Sr are taken into account: received in utero due to maternal intakes during pregnancy; received after birth from 90Sr accumulated by the fetus in utero; from intakes in breast milk; from intakes in the infant's diet after weaning. It is shown that doses to the fetus following maternal ingestion and subsequent transfer to the fetus via the placenta dominate the doses received for this particular individual for the first two years of life. Doses to the infant from intakes in breast milk are substantially lower but do make significant contributions to total doses in the first two years after birth. By about the age of two years residual 90Sr from placental transfer still contributes about the same dose as do intakes by the infant, but in later years doses from intakes by the infant dominate.

The Techa River Dosimetry System (TRDS) has been developed to provide estimates of dose received by approximately 30,000 members of the Extended Techa River Cohort (ETRC). Members of the ETRC were exposed beginning in 1949 to significant levels of external and internal (mainly from (90)Sr) dose but at low to moderate dose rates. Members of this cohort are being studied in an effort to test the hypothesis that exposure at low to moderate dose rates has the same ability to produce stochastic health effects as exposure at high dose rates. The current version of the TRDS is known as TRDS-2000 and is the subject of this paper. The estimated doses from (90)Sr are supported strongly by approximately 30,000 measurements made with a tooth beta-particle counter, measurements of bones collected at autopsy, and approximately 38,000 measurements made with a special whole-body counter that detects the bremsstrahlung from (90)Y. The median doses to the red bone marrow and the bone surface are 0.21 and 0.37 Gy, respectively. The maximum doses to the red bone marrow and bone surface are 2.0 and 5.2 Gy, respectively. Distributions of dose to other organs are provided and are lower than the values given above. Directions for future work are discussed.

A number of radiation accidents occurred at the "Mayak" plutonium production complex (Southern Urals, Russia) in 1950-60s that resulted in environmental contamination of large territories in the Southern and Middle Urals with long-lived radionuclides (90Sr, 137Cs). The results of long-term radiological monitoring were compiled into special databases at the Urals Research Center for Radiation Medicine, which allow the study of 90Sr behaviour in the environment and its accumulation in the human body. Retrospective analysis of the data on postmortem measurements of 90Sr in bones performed on residents of the Urals region over 1957-1988 were conducted for the first time. A time-dependence of 90Sr accumulation in the human body upon its density in soils was observed. Age and gender characteristics of 90Sr retention in bones were studied. It was shown that the levels of 90Sr in residents of large territories north and north-east of Chelyabinsk region, and of bordering territories of Sverdlovsk region were several times higher than the average values for the Russian Federation. Based on the measurements the direct dependence of 90Sr content in the skeleton on 90Sr density in soils was observed 30 years after the 1957 accident (the so called "Kyshtym accident"). However, for individual settlements this dependence may be weakened as a result of the influence of different biological and social factors. No influence of gender on 90Sr accumulation in the skeleton was found in the study. The analysis of age characteristics of 90Sr accumulation in bone, as influenced by skeleton growth and maturation, showed maximal levels of 90Sr from global fallout to be accumulated in bones of the persons born in 1949-1955.

The Mayak Production Association released large amounts of 90Sr into the Techa River with peak amounts in 1950-1951. Residents near the Techa River ingested an average of approximately 3,000 kBq of 90Sr. The affected people have been followed by scientists at the Urals Research Center for Radiation Medicine. The whole-body content of 90Sr of approximately 15,000 individuals has been measured over a period of 24 years (1974-1997) using a special whole-body counter. This report evaluates the gender and age dependences of individual rates of strontium elimination. Data on persons who had been measured 12 or more times were selected for study. There were 108 men and 81 women older than 30 years who met this criterion. Individual measurement results were fitted to an exponential function and grouped mean averages of the rate of strontium elimination as a function of age for each sex were derived. For men, a significant increase (from 2.8% year(-1) to 3.2% year(-1)) in the rate of strontium elimination after age 55 years is seen. For women, the increase in the rate of elimination was significant at age 45 and reached 5.8% year(-1) after the age of 60. The results may be used to develop a gender- and age-dependent model of strontium metabolism.

An age- and gender-dependent biokinetic model for strontium was developed based on the study of a population living along the Techa River exposed to effluents from the Mayak Production Association (MPA). To estimate the parameters of a new model (Techa biokinetic model, TBM) many data sets have been assembled: our whole-body counter data on long-term retention of 90Sr in humans, data from studies during the period of global fallout, data resulting from deliberate injection of strontium radionuclides and non-radiological data regarding bone formation and resorption, mineral content of the body, etc. The model was developed using the basic structure of the ICRP biokinetic model for strontium, but new age- and gender-specific parameters were derived. This paper discusses the approaches applied to develop the new model.

A whole body counter (WBC) designed to measure bremsstrahlung from 90Y, the short-lived daughter of 90Sr, has been used since 1974 to measure 90Sr-body burdens in residents along the Techa River, which was contaminated by releases from the Mayak Production Association. Bayes' rule has been applied to the a posteriori WBC data in order to derive the uncertainties associated with the data: The lower limit of reliable detection is 2.0 kBq and the uncertainty of routine measurements is 1.6 kBq.

The Mayak Production Association (MPA) was the first facility in the former Soviet Union for the production of plutonium. As a result of failures in the technological processes in the late 1940's and early 1950's, members of the public were exposed via discharge of about 10(17) Bq of liquid wastes into the Techa River (1949-1956). Residents of many villages downstream on the Techa River were exposed via a variety of pathways; the more significant included drinking of water from the river and external gamma exposure due to proximity to sediments and shoreline. The specific aim of this project is to enhance the reconstruction of external and internal radiation doses for individuals in the Extended Techa River Cohort. The purpose of this paper is to present the approaches being used to evaluate the uncertainty in the calculated individual doses and to provide example and representative results of the uncertainty analyses. The magnitude of the uncertainties varies depending on location and time of individual exposure, but the results from reference-individual calculations indicate that for external doses, the range of uncertainty is about a factor of four to five. For internal doses, the range of uncertainty depends on village of residence, which is actually a surrogate for source of drinking water. For villages with single sources of drinking water (river or well), the ratio of the 97.5th percentile-to 2.5th percentile estimates can be a factor of 20 to 30. For villages with mixed sources of drinking water (river and well), the ratio of the range can be over two orders of magnitude.