Chromosome analysis of workers occupationally exposed to radiation at the Sellafield nuclear facility

Purpose: To investigate the relationship between stable chromosome aberration frequency in peripheral blood lymphocytes and occupational cumulative radiation exposure. Materials and methods: Cytogenetic analysis using G-banding was performed on peripheral blood lymphocyte cultures from 104 workers from the British Nuclear Fuels PLC facility at Sellafield, UK. The study group comprised 61 men with lifetime cumulative doses > 500 mSv, 39 men with minimal exposure (i.e. <50 mSv) who formed a control group and 4 men with intermediate doses. Results: The slope of the dose-response, adjusted for smoking status, for translocations and insertions was 0.55 +/- 0.31 x 10(-2)/cell/Sv. Consideration of chromosome breakpoints for all aberrations combined in the radiation workers revealed an excess in the C group chromosomes and a deficit in the F group chromosomes with breakpoints being concentrated in the terminal regions whereas the distribution in the control group did not deviate from expectation. Conclusions: The dose-response was not significantly different from the parallel FISH analysis (Tucker ct al. 1997) and confirms that chronic radiation exposure appears to be substantially less effective at inducing stable chromosome aberrations in comparison with acute exposure.