Estimation of radon exposures to workers at the Fernald Feed Materials Production Center 1952-1988.
Hornung-RW; Pinney-SM; Lodwick-J; Killough-GG; Brewer-DE; Nasuta-J
J Expo Sci Environ Epidemiol 2008 Sep; 18(5):512-523
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.
Radiation; Dosimetry; Exposure-levels; Exposure-methods; Uranium-compounds; Radioactive-materials; Radioactive-contaminants; Waste-disposal; Exposure-assessment; Surfactants; Lung-cancer; Respiratory-system-disorders; Pulmonary-system-disorders; Workplace-studies
Dr. S.M. Pinney, Department of Environmental Health, University of Cincinnati, P.O. Box 670056, Cincinnati, Ohio 45167-0056
Journal of Exposure Science and Environmental Epidemiology
University of Cincinnati, Cincinnati, OH