Development for detecting the early health effect of fiber inhalation and constructing the risk assessment system of the fiber.

Test, fibers used in this experiment were glass wool, rock woolceramic fiber and potassium octatitanate whisker. The four steps for detecting health effect wereconducted.First, Step：Identification of the phycisco -chemical and geometric properties of fibers.The following propertieswere investigated for test fibers；fiber diameter, fiber length, solubility in distilled water and Gamble solutionsurface property (Zeta-potential), specific surface area, solid density，chemical compounds.Second step：biopersistence in lungs for test fibers by intratracheal instillation method.The hamsters wereinjected to fibers (2mg) by intratracheal instillation methods. The hamsters were sacrificed 3 daysand 3 months after the injection. the amount of remained in the lungs . the amount of remained in the lungs . theresult showed that the biopersistence was potassium octatitanate whisker = ceramic fiber > rock woolglass wool.Third step：biopersistence in lungs by short-term inhalation based on the second step.The rats were exposed topotassium octatitanate whisker by one month inhalation study (10ng/m6小时/天，5天/周). The biological half time was decided to 3.5 months.Fourth step：biopersistence in lungs and histopathological findings long-term inhalation.The rats were exposedto potassium octatitanate whisker by year inhalation study (1.9mg/m3；6 hours / days,. The biological half time decided to 15 months. For histopathological findings，there were no tumor，but the fibrotic changes were observed in au exposed rates . the result shows that the fiber amounts inthe lungs over the critical point caused the prolongation of the biopersistence of fibers in thelungs and the fibrotic changes of the lungs。

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.