title: Measurement of the biotransfer and time constant of radon from ingested water by human breath analysis.
abstract: Forty-one tests were performed on 38 volunteers to measure elimination rates of 222Rn 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 our flow-through scintillation cell was accomplished using a medical ventilator and 222Rn reservoir for 5-15 L min-1 flow rates. We 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. Our observations of bio-retention half-times range from 17-400 min. The whole-body dose calculations yield a mean of 2.70 +/- 3.43 nGy Bq-1, and the stomach dose calculations yield a mean of 276 +/- 186 nGy Bq-1. These means range beyond those previously reported.
authors.affiliation: Department of Physics, University of Maine, Orono 04469.
authors.forename: W L
authors.initials: WL
authors.lastname: Brown
authors.forename: C T
authors.initials: CT
authors.lastname: Hess
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001944:Breath Tests; D002648:Child; D004326:Drinking; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011886:Radon / Q000493:pharmacokinetics*; D013997:Time Factors; D014875:Water Pollutants, Radioactive / Q000493:pharmacokinetics*; D014881:Water Supply
chemical_list: D014875:Water Pollutants, Radioactive; D011886:Radon