YAMATO Hiroshi UOEH, lnst. of Ind. Ecol. Sci. Assoc. Professor, 産業生態科学研究所, 助教授 (90248592)
HORI Hajime UOEH, lnst. of I School of Health Sciences Professor, 産業保健学部, 教授 (70140902)
HIGASHI Toshiaki UOEH, lnst. of Ind. Ecol. Sci. Professor, 産業生態科学研究所, 教授 (10119000)
OHGAMI Akira UOEH, lnst. of Ind. Ecol. Sci. Research Assoc., 産業生態科学研究所, 助手 (40301692)
MORIMOTO Yasuo UOEH, lnst. of Ind. Ecol. Sci. Assoc. Professor, 産業生態科学研究所, 助教授 (30258628)
Test, fibers used in this experiment were glass wool, rock wool, ceramic fiber and potassium octatitanate whisker. The four steps for detecting health effect were conducted.
First, Step : Identification of the physico-chemical and geometric properties of fibers.
The following properties were investigated for test fibers ; fiber diameter, fiber length, solubility in distilled water and Gamble solution, surface property (Zeta-potential), specific surface area, solid density, chemical compounds.
Second step : biopersistence in lungs for test fibers by intratracheal instillation method.
The hamsters were injected to fibers (2mg) by intratracheal instillation methods. The hamsters were sacrificed 3 days and 3 months after the injection. The amount of remained in the lungs were detected by ICP-AES. The result showed that the biopersistence was potassium octatitanate whisker = ceramic fiber > rock wool >> glass wool.
Third step : biopersistence in lungs by short-term inhalation based on the second step.
The rats were exposed to potassium octatitanate whisker by one month inhalation study (10ng/mィイD13ィエD1 ; 6hours/days, 5days/week). The biological half time was decided to 3.5 months.
Fourth step : biopersistence in lungs and histopathological findings by long-term inhalation.
The rats were exposed to potassium octatitanate whisker by one year inhalation study ( 1.9mg/m3 ; 6hours/days, 5days/week). The biological half time was decided to 15 months. For histopathological findings, there were no tumor, but the fibrotic changes were observed in au exposed rats.
The result shows that the fiber amounts in the lungs over the critical point caused the prolongation of the biopersistence of fibers in the lungs and the fibrotic changes of the lungs.