title: Estimation of radon exposures to workers at the Fernald Feed Materials Production Center 1952-1988.
abstract: The Feed Materials Production Center (FMPC) at Fernald, Ohio produced uranium metal products for use in Department of Energy defense programs. Radium-contaminated waste material was stored on-site in two K-65 silos on the west side of the facility and provided a source of 222Ra. The initial objective of this study was to estimate radon exposures to employees at FMPC working from 1952 to 1988. A modified Gaussian plume model was used to estimate exposures to workers. In an effort to validate these model-based estimates, we used 138 CR-39 film assays from window glass sampled in buildings throughout the site. Results from the CR-39 assays indicated a second substantial source of radon, the smaller Q-11 silos located in the production area. A response-surface regression analysis using a cubic spline model was fit to the CR-39 data to estimate 210Po surface activity levels at geographic coordinates throughout the facility. Knowledge of the age of the glass, the amount of contaminated waste in the Q-11 silos, and 210Po decay rates were used to estimate annual exposures to radon decay products (WLM: working level months). Estimated WLM levels associated with the Q-11 source term indicated that employees working in the vicinity during the period when they were filled with radium-contaminated waste (1952-1958) received substantially higher radon exposures than those from the K-65 source during this period. Results of the two models, corresponding to the K-65 and Q-11 sources, were combined to estimate WLM levels by year for each of the 7143 Fernald workers during the period 1952-1988. Estimated cumulative exposures to individual workers ranged from <0.5 to 751 WLM. Estimated radon exposures from this newly discovered source have important implications for future epidemiologic studies of lung cancer in workers at the Fernald facility.
authors.affiliation: Cincinnati Children's Environmental Health Center, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.
authors.forename: Richard W
authors.initials: RW
authors.lastname: Hornung
authors.forename: Susan M
authors.initials: SM
authors.lastname: Pinney
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Lodwick
authors.forename: George G
authors.initials: GG
authors.lastname: Killough
authors.forename: David E
authors.initials: DE
authors.lastname: Brewer
authors.forename: James
authors.initials: J
authors.lastname: Nasuta
mesh_terms: D000392:Air Movements; D000396:Air Pollutants, Radioactive / Q000032:analysis*; D000398:Air Pollution, Radioactive / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods; D006207:Half-Life; D006801:Humans; D009314:National Institute for Occupational Safety and Health, U.S.; D016011:Normal Distribution; D016273:Occupational Exposure / Q000032:analysis*; D009820:Ohio; D010865:Pilot Projects; D011829:Radiation Dosage; D011886:Radon / Q000032:analysis*; D012044:Regression Analysis; D018570:Risk Assessment / Q000379:methods; D011795:Surveys and Questionnaires; D013997:Time Factors; D014481:United States
chemical_list: D000396:Air Pollutants, Radioactive; D011886:Radon