title: Biological dosimetry of radiation workers at the Sellafield nuclear facility.
abstract: The British Nuclear Fuels plc facility at Sellafield performs a range of nuclear-related activities. The site has been in operation since 1950 and has, in general, employed a stable work force, many of whom have accumulated relatively high occupational exposures to ionizing radiation. This paper compares the physical dosimetry with two biological end points for evaluating radiation exposure: fluorescence in situ hybridization with whole-chromosome painting probes to quantify stable chromosome aberrations (translocations and insertions), and glycophorin A (GPA) analysis of variant erythrocytes. For the cytogenetic analyses, 81 workers were evaluated in five dose categories, including 23 with minimal radiation exposure (< or = 50 mSv) and 58 with exposures ranging from 173 to 1108 mSv, all but 3 being > 500 mSv. In a univariate analysis, the mean stable chromosome aberration frequencies showed a significant increase with dose category (P = 0.032), and with cumulative dose when dose is treated as a continuous variable (P = 0.015). The slope of the dose response for stable aberrations is 0.79 +/- 0.22 aberrations per 100 cells per sievert (adjusted for smoking status), which is less than that observed among atomic bomb survivors, and suggests a dose and dose-rate effectiveness factor for chronic exposure of about 6. Analyses of the data for GPA N/O and N/N variants from 36 workers revealed no correlation with dose. Neither was there a correlation between the frequencies of N/O GPA variants and stable aberrations, although a weak negative association was observed between N/N variant frequency and stable aberrations (r = -0.38, P = 0.05). These results provide clear evidence for the accumulation of stable aberrations under conditions of chronic occupational exposure to ionizing radiation and show that stable chromosome aberrations are a more sensitive indicator for chronic radiation exposure than GPA variants. In comparison with human studies of brief exposure, chronic low-dose exposures appear substantially less effective for producing somatic effects as reflected by stable chromosome aberrations.
authors.affiliation: Biology and Biotechnology Research Program, Lawrence Livermore National Laboratory, Livermore, California 94551-9900, USA.
authors.forename: J D
authors.initials: JD
authors.lastname: Tucker
authors.forename: E J
authors.initials: EJ
authors.lastname: Tawn
authors.forename: D
authors.initials: D
authors.lastname: Holdsworth
authors.forename: S
authors.initials: S
authors.lastname: Morris
authors.forename: R
authors.initials: R
authors.lastname: Langlois
authors.forename: M J
authors.initials: MJ
authors.lastname: Ramsey
authors.forename: P
authors.initials: P
authors.lastname: Kato
authors.forename: J D
authors.initials: JD
authors.lastname: Boice
authors.forename: R E
authors.initials: RE
authors.lastname: Tarone
authors.forename: R H
authors.initials: RH
authors.lastname: Jensen
mesh_terms: D002478:Cells, Cultured; D002869:Chromosome Aberrations; D004251:DNA Transposable Elements; D004307:Dose-Response Relationship, Radiation; D004912:Erythrocytes / Q000528:radiation effects; D005373:Film Dosimetry; D014644:Genetic Variation; D006021:Glycophorins / Q000235:genetics; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008875:Middle Aged; D009689:Nuclear Warfare; D016273:Occupational Exposure; D011210:Power Plants; D011829:Radiation Dosage; D011839:Radiation, Ionizing; D012044:Regression Analysis; D012907:Smoking; D014178:Translocation, Genetic; D006113:United Kingdom
chemical_list: D004251:DNA Transposable Elements; D006021:Glycophorins