||Measurement of the Biotransfer and Time Constant of Radon from Ingested Water by Human Breath Analysis.
Brown, W. L. ;
Hess, C. T. ;
||Maine Univ. at Orono. Dept. of Physics and Astronomy.;Environmental Protection Agency, Cincinnati, OH.
Radon 222 ;
Breath tests ;
Scintillation counting ;
Potable water ;
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Forty-one tests were performed on 38 volunteers to measure elimination rates of (222)Rn in expired breath. Participants ranged from ages 9 to 85 y, with 16 males and 22 females. The levels of physical activity of the subjects ranged from very inactive to marathon level. Calibration of the flow-through scintillation cell was accomplished using a medical ventilator and (222)Rn reservoir for 5-15 L/min flow rates. The authors found a wide range of percent elimination (12-68%) in 30 min. The percent elimination has a mild correlation with the predicted forced expiratory volume in 1 s and with time passed since eating. Their observations of bio-retention half-times range from 17-400 min. The whole-body dose calculations yield a mean of 2.70 + or - 3.43 nGy/Bq, and the stomach dose calculations yield a mean of 276 + or - 186 nGy/Bq. These means range beyond those previously reported. (Copyright (c) 1992 Health Physics Society.)