Monte Carlo modeling of beta-radiometer device used to measure milk contaminated as a result of the Chernobyl accident

Activity concentrations of 131I and other radionuclides in cow's milk in Belarus during the first month following the Chernobyl accident

The accident at the Chernobyl nuclear power plant (NPP) in Ukraine on April 26, 1986 led to a considerable release of radioactive material resulting in environmental contamination over vast areas of Belarus, Ukraine and western Russian Federation. The major health effect of the Chernobyl accident was an increase in thyroid cancer incidence in people exposed as children and adolescents, so much attention was paid to the thyroid doses resulting from intakes of ¹³¹I. Because cow's milk consumption was the main source of ¹³¹I intake by people, it was important to measure the ¹³¹I activity concentrations in cow's milk to calculate, or to validate, the thyroid doses to the exposed population. Almost 11,000 measurements of total beta-activity in cow's milk were performed using a DP-100 device during the first month after the Chernobyl accident in the most contaminated regions of Belarus. Using an ecological model and calibration coefficients for the DP-100 device the activity concentration of ¹³¹I in cow's milk was derived as well as the activity concentrations of the other radiologically important radionuclides, namely ¹³⁴Cs, ¹³⁷Cs, ⁸⁹Sr and ⁹⁰Sr. The activity concentrations of other radionuclides, such as ⁹⁰Y, ¹³²Te, ¹³²I, ¹³³I, ¹³⁶Cs, ¹⁴⁰Ba, ¹⁴⁰La, ¹⁴¹Ce and ¹⁴⁴Ce, in cow's milk were also estimated and were shown to be of minor importance. The concentrations of ⁹⁵Zr, ⁹⁵Nb, ¹⁰³Ru and ¹⁰⁶Ru in cow's milk were negligible. The data obtained in this study were validated by comparing derived ¹³¹I and ¹³⁷Cs concentrations in cow's milk with gamma-spectrometry measurements performed in milk produced in the same location close to the same date. The results of this study were essential to assess and validate the radiation doses received by the subjects of epidemiological studies related to the health consequences of the Chernobyl accident.

Doses for post-Chernobyl epidemiological studies: are they reliable?

On 26 April 2016, thirty years will have elapsed since the occurrence of the Chernobyl accident, which has so far been the most severe in the history of the nuclear reactor industry. Numerous epidemiological studies were conducted to evaluate the possible health consequences of the accident. Since the credibility of the association between the radiation exposure and health outcome is highly dependent on the adequacy of the dosimetric quantities used in these studies, this paper makes an effort to overview the methods used to estimate individual doses and the associated uncertainties in the main analytical epidemiological studies (i.e. cohort or case-control) related to the Chernobyl accident. Based on the thorough analysis and comparison with other radiation studies, the authors conclude that individual doses for the Chernobyl analytical epidemiological studies have been calculated with a relatively high degree of reliability and well-characterized uncertainties, and that they compare favorably with many other non-Chernobyl studies. The major strengths of the Chernobyl studies are: (1) they are grounded on a large number of measurements, either performed on humans or made in the environment; and (2) extensive effort has been invested to evaluate the uncertainties associated with the dose estimates. Nevertheless, gaps in the methodology are identified and suggestions for the possible improvement of the current dose estimates are made.