NON-OCCUPATIONAL OUTDOOR AND INDOOR EXPOS URE TO ASBESTOS DUST

Results of a case-control study into factors affecting the development of diffusive malignant mesothelomia (DMM) showed health risks due to outdoor and indoor exposure to asbestos. It has to be investigated whe ther or not these findings are confirmed by international indoor and o utdoor measurements of asbestos concentrations and our own and interna tional lung tissue fibre analyses. Compared to the general population a significantly increased risk could be shown both in terms of a cumul ative dose of about one fibre-year and of an amphibole fibre concentra tion L greater than or equal to 5 mu m in the lung tissue of 100 000 f ibres per gram dry (F/g(tr)). A cumulative dose of this quantity must be due to the inhalation of considerably more than 1000 F/m(3) over a longer period of time. Even in the vicinity of asbestos cement facades or in areas of concentration, outdoor measurements do not normally re veal asbestos concentrations of this extent. Relatively high concentra tions in the neighbourhood of industrial emitters are more likely to c ause such results. Sometimes increased asbestos concentrations much gr eater than 1000 F/m(3) are found in buildings with poorly bound asbest os-containing products such as injected insulating layers and fire pro tection plates. If these products are protected from damage, the occur rence of hazardous concentrations can be largely avoided. Lacking risk awareness in the past, however, may have been the reason for increase d risks particularly in connection with repair work and maintenance. A sbestos exposure due to thermal storage heating stoves seems to be les s critical. Yet special risks may occur when women are handling contam inated working clothes of their husbands at home. Lung tissue fibre an alyses showed clearly increased amphibole fibre concentrations L great er than or equal to 5 mu m >1 million F/g(tr) for four DMM-patients wi thout occupational asbestos exposure. Family members of two of them we re working with asbestos and additionally one of them suffered from a neighbourhood exposure. Two others turned out only to be exposed at ho me by a thermal storage heating stove respectively by an asbestos ceme nt facade. Chrysotile fibre concentrations of greater than or equal to 1 million F/g dry were found for three other patients with a neighbou rhood exposure. International publications speak of increased asbestos fibre concentrations in the lung tissue particularly in cases where t here is a neighbourhood exposure or an exposure by clothes of family m embers.