2006 年 35 巻 1 号 p. 22-33
Characterization of man-made rock-wool fibers were investigated by using optical and electron microscopic techniques and discussed how to affect on human health. The rock-wool fibers were collected from spraying on the roof. Mineralogical analyses were carried out by X-ray powder diffraction. Most fibers can exist as straight or curved fine threads with sharp points μm-nm in diameter under electron microscopy observations. The rock-wool is complex agglomerates of fibers and fumes with cement of calcite. The shape and size are significantly important factors for hazardous assessment of man-made fibers. The fibers are easily adhering to protein-rich spherical materials in 1% BSA (bovine serum albumin) and in ringer’s solution for few days aging. Spherical protein-like materials are similar to “asbestos body” with dumbbells shape. Man-made fibers have been manufactured for over 20 years, but there have been few concerns raised regarding the safety of rock-wool, were considered to be non-hazardous, because of the different durability in the lung. Present study consistently suggests that man-made fibers with fine and sharp points have similar risk as carcinogen of asbestos. The results of both patch test and adhesion materials with dumbbells shape provide clues regarding the mechanisms of tolerance in the lungs of exposed animals, and may be relevant for humans.