[Chromosome alterations in workers exposed to ionizing radiation].

With the purpose of determining and characterizing chromosomal alterations and their relation to the radiation dose, time of employment and weekly exposure time, a transversal cut-descriptive study was performed on 18 workers, exposed to ionizing radiation, from a specialized company in the Venezuelan oil industry. These workers, male and females, constituted all the population studied, aged between 32 and 59 years, with at least one year on the job. A random sample of a non-exposed group of workers was used as a control. An occupational medical report was applied and personal dosimetry, environmental monitoring and a chromosomal analysis using two chromosomic culture techniques, were performed. The results show, in the exposed groups, an age average of 46.10 +/- 7.69 years, an average 17.5 +/- 5.00 years of employment and a weekly exposure of 4.30 +/- 1.33 hours. In the exposed population, 444 chromosomal abnormalities were evidenced in 700 metaphases studied; these abnormalities consisted of 66.6% single fragilities, 22% of combined fragilities, with chromosomic ruptures, deletions and poliploids, and 11% presented a normal kariotype. The control group presented chromosomic alterations as single fragilities in 55% of the cases. Radiologists presented 88.8% of chromosomic alterations, with below permissible doses detected, and 11.2% of them with exceed doses, presented the greatest number of fragilities and multiple chromosomic ruptures. The radiologists with weekly exposures of 8 hours presented the highest number of chromosomic alterations. 88% of radiologists with chromosomal abnormalities had more than 10 years of exposure. In conclusion, chronic exposure to low levels of ionizing radiation can induce chromosomic alterations, depending on the years of employment and the weekly time of exposure.