L. K. Bezdrobna1, L. V. Tarasenko1, T. V. Tsyganok1, V. A. Kurochkina1,
V. O. Sushko2, L. I. Shvayko2
11Institute for Nuclear Research of the National Academy of Sciences of Ukraine, Nauky prospect 47,
Kyiv, 03680, Ukraine
2State Institution «National Research Center for Radiation Medicine of the National Academy of Medical Sciences of Ukraine», Melnykova str., 53, Kyiv, 04050, Ukraine
Cases of the staff unaccounted exposure during the construction of the protective shell for a new confinement at the ChNPP site
Objective: cytogenetic control of the staff radiation exposure level during the construction of the protective shell for a new confinement at the ChNPP site.
Materials and methods. A cytogenetic examination was carried out for 32 staff persons from the contracting organizations involved into construction of the protective shell for a new confinement. Additionally, for the goal of comparison, 28 persons who did not have professional contacts with the radiation factors were inspected. The analytical method of the aberrations on preparations of uniformly stained chromosomes of the peripheral blood lymphocytes has been used. The frequency has been determined for the dicentrics and centric rings with an accompanying pair fragment for 100 analyzed metaphases. The staff chronic exposure absorbed doses are estimated by means of the linear part of the linear-quadratic equations, which describe the calibration dose dependence of the unstable chromosomal exchanges yield in the acute irradiated blood samples in vitro.
Results. Six staff persons from 32 investigated ones have the individual frequency of the recent exposure specific markers (unstable chromosomal exchanges with accompanying pair fragments) significantly higher than those for the comparison group and the population average spontaneous level. It indicates on the possibility of their excessive irradiation during the work execution in the ChNPP zone. Single cells with two chromosomal exchanges were registered for three persons, while such cells were absent in the comparison group. This is the result of the incorporation of radionuclides, which are available in the air at the workplaces. The calculated averaged individual absorbed doses caused by the recent exposure of six staff persons lies in the range from 102.5 to 371.0 mGy.
Conclusion. The doses calculated from the frequency of unstable chromosomal exchanges with the accompanying pair fragment caused by the recent exposure of six staff persons are exceeding significantly the doses determined by the methods of physical dosimetry and the occupational exposure dose limits.
Key words: Chornobyl NPP, new confinement, personnel, cytogenetic dosimetry, chromosomal aberrations, culture of blood lymphocytes.
Problems of radiation medicine and radiobiology. 2017;22:316–322.
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