Bone mineral density in residents of radioactive territories of Chelyabinsk Region

Operation of the Mayak plutonium production association resulted in radioactive contamination of a part of Chelyabinsk Region in the 1950–1960s. Significant gas-aerosol emission of ¹³¹I occurred since 1948; in 1957, a radiation accident resulted in ⁹⁰Sr contamination of large territories. This paper presents comparison of the bone mineral density of persons who lived on territories with different levels of ⁹⁰Sr-soil contamination with that of a control group. It was found that in 1970–1975, the bone mineral density, estimated from the mineral content in bone samples, in residents of contaminated areas born in 1936–1952 was significantly lower compared to the control group. For persons born in 1880–1935, such differences were not found. It was shown that the decrease in the 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 is not significant. The decrease in bone mineral density of persons born in 1936–1952 may be associated with exposure of the thyroid and parathyroid glands (systemic regulators of calcium metabolism) to ¹³¹I from gas-aerosol emissions from Mayak. The highest levels of gas-aerosol emissions occurred in 1948–1954 and coincided with the growth and development of the thyroid gland, characterized by intensive accumulation of ¹³¹I, and with the growth and maturation of the skeleton of persons born in the given calendar years.