温泉医学領域における微量成分に関する研究

第II報 放射能泉地の空気中ラドン (Rn) 量の測定, Rn泉水応用後の呼気中Rn量の測定

抄録

Radon (Rn) contents were determined in the air of radioactive spa areas and in human expiratory air after the treatment with spring water using an ionization chamber equipped with vibrating reed electrometer.
The results were as follows.
(1) Rn contents in outdoor air at spa areas of Misasa, Sekigane and Ikeda were significantly higher than those at non-spa area of Kurayoshi city.
(2) At Misasa spa, Rn contents in outdoor air tend to increase from June to September in a year. There was a negative correlation between Rn contents in outdoor air and rainfall a day.
(3) Rn contents in the air of private house and health resort hotel at Misasa spa area were ranged from 0.5 to 1.5pCi/l and 0.6 to 3.5pCi/l, respectively. Rn contents in the air of facilities using springwater at Misasa brabch hospital Okayama University were determined; for exsample, the usual bathroom: 21.8±2.1pCi/l, the Hubbard bathroom: 143.4±69.8pCi/l and the drinking hall: 30-47pCi/l, respectively.
(4) Generally, Rn contents in expiratory air of persons living at Misasa spa area were not different from those at non-spa areas.
(5) Rn contents in the expiratory air reached a maximum about 40 minutes after the treatment in spring water bath, and the ratio of Rn in the expiratory air to that in spring water was about 1.1%.
Rn contents in the expiratory air showed a maximal level 40 to 60 minutes after a person entered into the drinking hall, and the ratio of Rn in the expiratory air to that in the air of drinking hall was about 85%.
(6) As the bathing time was longer, the subjects were younger, Rn contents in the expiratory air became higher during bathing in Misasa spring water.
The biological half-life of Rn contents in expiratory air of subjects after batning, inhalation (hot-air bathroom) and drinking of spring water was ranged from 40 to 43 minutes.
In use of radioactive spring water, utilized efficiency of Rn in the body was in order of inhaltion, bathing and drinking from the view of Rn contents in expiratory air.
(7) The ratio of Rn excretion in urine to total Rn intake was about 0.08% after the drinking of Misasa spring water.