日本でもアスベストによる死者が多数にのぼることが報道されて以来,アスベストは大きな社会問題となった。建材や天然鉱物中のアスベスト含有量の分析には,X線回折と位相差顕微鏡による分散染色法が主に使用され,熱分析によるアスベストの定性・定量分析は限られた場合にのみ用いられているが,その加熱分解挙動の把握は今後の溶融処理技術の開発を進める上で重要である。一番大量に使用されているクリソタイルは,600～700℃で脱水酸化反応が起こるが依然として繊維状を保持していることが確認されており,繊維状でなくなるには1100℃程度まで加熱する必要がある。左官用モルタル混和材中のクリソタイルの定量には微分熱重量法が推奨されている。アスベストの無害化処理には現在では1600℃以上の高温溶融が必要であるが,フッ化カルシウムなどを含むフロン分解物との混合物を700℃まで加熱すると粒子状の非アスベスト化合物に変化するなどの新しい低温処理研究も進められている。

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Asbestos fiber crystals were efficiently degraded by hydrofluoric acid, but not hydrochloric acid, sulfuric acid and nitric acid. Asbestos fiber crystals were completely degraded by 15% hydrofluoric acid within 2 hours at room temperature. The results of TEM micrographs, corresponding selected area diffraction patterns (SADP) and X-ray diffraction measurements obviously demonstrated that asbestos fiber crystals were reacted with hydrofluoric acid to generate magnesium fluoride and magnesium hexafluorosilicate. A high concentration of hydrofluoric acid remained in a wastewater after treatment of asbestos with 15% hydrofluoric acid for 2 hours was properly processed. After having processed the wastewater, the concentration of fluorine ion was 1.8 mg/l. These results suggest that the method consisting of a degradation of asbestos with hydrofluoric acid and a subsequent processing of wastewater may be useful for removing resolution of asbestos.

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近年，わが国の職業がんの中で石綿中皮腫と石綿肺がんは，その数・割合とも著明に増加しており，労働安全衛生の中で石綿は当面重要課題の一つであり続けることは疑いない．本報ではわが国における石綿と労働安全衛生法（安衛法），特定化学物質障害予防規則（特化則），石綿障害予防規則（石綿則）等の法体系・行政通達との関係について行政資料を中心に検討し概説する．特にわが国で石綿が全面禁止に至った経緯，労働者の曝露防止対策，管理濃度等の変遷，石綿作業従事労働者の健康管理の各側面について焦点を当てる．

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In June 2005, media coverage of the health effects of asbestos used at factories on nearby residents developed into an “asbestos panic” in Japan. Asbestos is a natural mineral fiber and is widely used as a material for industrial and construction purposes because of its significant tensile strength, heat resistance and thermal insulating properties. Japan′s Ministry of Health, Labor and Welfare has proposed a new regulation for the prevention of asbestos scattering due to building demolition. Here, we provide a brief overview of asbestos from the viewpoints of present and future problems.

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It has been established that asbestos is associated with asbestosis (pneumoconiosis) , lung cancer and mesothelioma. These health effects are characterized by the following factors: (1) because of the long latency period between exposure and onset of extrinsic malignant neoplasms, the need for earlier preventative measures were left unrecognized; (2) malignant mesothelioma can be developed following exposure at environmental levels; (3) lung cancer is a major malignant neoplasm in which other factors are involved and there is evidence to suggest that the two factors of asbestos exposure and cigarette smoking are synergistic.
Japan has been criticized for being slow to take action, however, it is true, in general, that the status quo of each country is taken into consideration in the application of scientific findings. In retrospect it can be said that there was no validity of the continued use of asbestos in the late 1980s in Japan in terms of its economic status and technological level at that time.
It was also a lesson in creating a mechanism to apply scientific findings to society and determining how the human factor is to be dealt with. The Japan Association of Aerosol Science and Technology will bear responsibility in promoting the spread of information to society when hazardous health effects of new particulate matter are discussed.
The following principles included in EU policy are thought to follow: (1) precautionary principle; (2) prevention principle; (3) ratification at source principle; and (4) polluter pays indemnity principle.

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アスベストを原因とする中皮腫は, ほとんど突然のように平成17年 (2005) にマスコミを賑わせた. しかし, 医学的あるいは環境衛生学的には, そのずっと以前から問題視されていたことは周知のことである. 戦前から戦中, そして戦後にかけてのアスベスト (石綿) の使用状況の変化が示すところによれば, わが国では高度経済成長期にきわめて有用な建築資材として多く使われたことが特徴的である. また, アメリカやイギリス, フランスなど諸外国での対応に比較してわが国の行政対応が遅れていたことが問題として指摘されている. こうした状況の中, 平成17年7月1日の『石綿障害予防規則』の施行直前に, 改めて社会的問題として大きく取り上げられたのである. アスベストは建築物に多く使用され, 製造作業者のみならず工場周辺の住民, 建築現場の作業者, 建築物利用者 (居住者や学童など) 多くの人々が影響を受ける. そのために, 行政的には多くの省庁がかかわる問題となっている. また, 疾患としての中皮腫の自然史が明確になっていないこと, 潜伏期間が長いことなどは, 医学的にも対応が難しいことを示している. さらに, わが国では1970, 80年代がアスベスト使用のピークであり, 今後10-20年後にさらに多くの中皮種の発症が予測されている. 以上のように, アスベストに起因する中皮腫は戦後における効率優先の経済開発によって生じた問題として位置づけることができる. 医学的問題の背後にある社会的, 歴史的背景を重視して問題を考えたい.

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In recent years, the health of many people is damaged by asbestos. Therefore, to detect very small quantity of asbestos that exists in general environment is very important. According to an officially fixed way, existence of asbestos in a certain building material is discriminated according to whether there are more than 4 crystals of asbestos per 3000 particles in samples made with crushing a part of the building material. The particle counting is performed manually, therefore it needs great time and labor. For automation, some studies to count particle with image processing are performed. To ensure consistency with conventional manual method, the automated method should be able to obtain equivalent outcome to manual methods. In this paper, we propose an automatic particle count method based on multiresolution analysis. At first, the classifier which can distinguish existence or nonexistence of a particle at the center of ROI (region of interest) is constructed. Next, the image is scanned with the classifier on multiresolution, and small areas containing a particle are found. To construct the classifier according to the counting result by manual method, we can achieve the result as same as manual one by the proposed method. To confirm validity of the proposed method, we did some experiments to apply the method to the images that particles are identified manually. As the result, we confirmed that 10% of false positive and false negative are contained respectively. Because the proportions are roughly same, the total count is as same as manual counting.

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