トイレの衛生 : 水洗時の飛沫と細菌汚染 Toilet Hygiene : Droplets Production during Flushing and Bacterial Contamination
More than half of woman university students inquired proved that they flushed toilets just to cover the sounds while urinating. To see if the droplets produced during a flushing would be an source of infection, the existence of bacteria in them was examined and the number and distribution of droplets were determined under "in use" conditions both in Japanese- and Western-style toilets in Tama Campus of Tokyo Kasei Gakuin University. A number of bacteria seeded into toilets were shown to eject from the toilet bowl during flushing. On the average, Japanese- and Western-style toilets produced 9 and 7 droplets, respectively during one flushing and the distribution pattern of them was related to the water flow in both toilets. The number of droplets incresed almost in proportion to the length of time when the valve was being held. The probable number of bacteria which could reach human body was calculated based on the results of these experiments. Although the droplets seemed to be an unlikely source, the probability of infection associated with them was not completely denied.