The estimation and potential radiobiological significance of the intake of 228Ra by early Ra dial workers in Illinois.

We made radiochemical determinations of 226Ra and the 228Ra-decay product, 228Th, in samples of bone from former Ra dial workers who belonged to a major cohort of Ra-exposed persons under study for health effects at our institution. Most of the former workers were long-term residents of two communities supplied with drinking water containing elevated natural levels of 228Ra and 226Ra, so determinations also were made of radioactivity in samples of bone from long-term residents not occupationally exposed to Ra. The 228Th activity of the bones of the former workers, after correction for the presence of natural radioactivity, showed that some had significant occupational intakes of 228Ra, contrary to published reports that 228Ra was never used by the Illinois company that had employed the cohort of early workers.

Postprandial changes in the exhalation rate of radon produced in vivo.

The rate of exhalation of radon by persons with long-standing radium burdens increases about twofold shortly after a meal. The increase is short-lived and "normal" values are regained in 1.5 to 2 hours.