The alpha spectrometry measurements of specific activity of 238Pu and 239Pu in urine from bioassay examinations of 1,013 workers employed at the radiochemical and plutonium production facilities of the Mayak Production Association and in autopsy specimens of lung, liver, and skeleton from 85 former nuclear workers who died between 1974-2009, are summarized.The accumulation fraction of 238Pu in the body and excreta has not changed with time in workers involved in production of weapons-grade plutonium production (e.g., the plutonium production facility and the former radiochemical facility). The accumulation fraction of 238Pu in individuals exposed to plutonium isotopes at the newer Spent Nuclear Fuel Reprocessing Plant ranged from 0.13% up to 27.5% based on the autopsy data. No statistically significant differences between 238Pu and 239Pu in distribution by the main organs of plutonium deposition were found in the Mayak workers. Based on the bioassay data,the fraction of 238Pu activity in urine is on average 38-69% of the total activity of 238Pu and 239Pu, which correlates with the isotopic composition in workplace air sampled at the Spent Nuclear Fuel Reprocessing Plant. In view of the higher specific activity of 238Pu, the contribution of 238Pu to the total internal dose, particularly in the skeleton and liver, might be expected to continue to increase, and continued surveillance is recommended.
Age and sex features of strontium metabolism have been analyzed on studies of the population residing on the banks of the Techa river which was contaminated by fission products during the years 1949-1956. Measurements of 90Sr body burden have been performed since 1974 using a whole-body counter, and these have made it possible to estimate age-specific long-term retention and elimination rates for men and women. Regarding the retention that correlated with the respective maturation ages, distinct sex differences have been observed for adolescents, whereas only postmenopausal women showed a sharp increase of their elimination rates. There were no differences concerning the reproductive ages. Our experimental findings have a clear physiological interpretation and can be used to develop metabolic models for bone-seeking radionuclides.
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 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.
The authors analysed 20-years and longer observations over health state of personnel having occupational contact with highly enriched uranium. Findings are no determined effects as clinical manifestations of chronic uranium intoxication, presented by most frequently involved systems (hemopoietic, bronchopulmonary) and main organs accumulating uranium (liver, kidneys, bones). Long-term observations revealed malignancies in 11% of the examinees. Further medical observations over the personnel (risk group) are required to evaluate risk of aleatory effects in prolonged contact with various uranium compounds.