Asbestos: elimination of asbestos-related diseases

岩石鉱物科学35, 310, 2006
榊原 正幸、上原誠一郎


The term asbestos is a generic designation given to six types of naturally occurring mineral fibers that are or have been used in commercial products. These fibers belong to two mineral groups: ser-pentines and amphiboles. The serpentine group contains a single asbestiform variety: chrysotile. The amphibole group contains five asbestiform amphibole varieties: anthophyllite, grunerite (amosite), riebeckite (crocidolite), tremolite and actinolite.These fibrous minerals share several properties which qualify them as asbestiform fibers. They are bundles of fibers which can be easily cleaved into thinner fibers. Several properties that make asbestos so versatile and cost effective are high tensile strength, chemical and thermal stabil-ity, high flexibility, and low electrical conductivity. Asbestos fibers have been used in a broad variety of industrial application; some 3000 appli-cations such as roofing products, gaskets, and friction products. 80% of imported asbestos is used for cement products such as asbestos boards and slates which are used for building materials, 7% for friction materials, and less than 3% for asbestos textile. Nearly all of the asbestos produced worldwide is chrysotile. Historically, chrysotile has accounted for more than 90% of the world’s asbestos production, and it presently accounts for over 99% of the world production. Two types of amphiboles, commonly designated as amosite and crocidolite are no longer mined. With the onset of the health issues concerning asbestos in the late 1960s and early 1970s, world production and consumption began to decline during the 1980s. Japan used approximately 6.7 million tons between 1974 and 2004. About 67% of this amount was used since 1930. The relationship between workplace exposure to airborne asbestos fibers and respiratory dis-eases is one of the most widely studied subjects of modern epidemiology. The research efforts resulted in significant consensus that asbestos fibers can be associated with diseases of asbestosis, lung cancer and mesothelioma. Its carcinogenic nature, an overall lack of knowledge of minimum safe exposure levels, and the long latency for the development of lung cancer and mesothelioma are the main contributing factors to these controversies.



・本日11/17(火)は、5時30分起床。朝勉して出勤。午前外来、午後ちょっと病棟よってかえり買い物をして15時30分帰宅。16時からZOOMで大学院のcritical appraisal.その後少しだけ先日切り倒していた木の枝を切って、入浴。夕食。その後講義のvideoみたりお勉強。そろそろ寝ましょうか。


nice!(1)  コメント(0) 

nice! 1

コメント 0