Document aLep6jBr0JgN22NG952DOv2a

53 *6 far it known - in agreement, with the results of other investigators. Finally it should he noted that there js an increasing tendency to report results of electron microscopic asbestos fibre determinations as gravimetric concentrations. The reason for this ir. that during preparation of the speci men the original fibres are broken down into fibrils, which means that there probably is no correlation between number of asbestos fibres counted with the electron microscope and the number of fibres originally present in the en vironment. 3. Food (see also <,4 beverages) No pertinent data on the asbestos content of food Is available. Qualita tively it can be said that its content depends on two kinds of asbestos sources: a. the natural background which depends on the natural asbestos content of soil and water, by passing through asbestos containing geological fora>ation, the latter can pick up considerable numbers of asbestos fibres (vide paragraph 4); b. asbestos which Js introduced by man's action. In this connection filtration using asbestos filters and the vise of talcum, which can contain asbestos, in food, medical preparations, etc. should be mentioned. 3. Soil Asbestos is the generic term for a number of hydrated silicates which can be separated into flexible fibres (see Chapter 1). Though commercial de posits arc- found mainly outside Western Purope, the minerals arc widely dis tributed and in some regions the soil can contain large amounts of asbestos. This is well known in regions of Finland and bulgaria but Isolds too for re gions in Italy and France. Jt is clear that at these places t) best os exposure level can bA considerable but no quantitative data av liable. 4. Watcr_end beverages A restricted number of data are available for asbestos particles in ground, surface and drinking water in mains and at the tap of the consumer. Most Of the data relates to serpentine rock containing areas in Canada and in the U.S.A. The first published data origined from Cunningham and Pontefract B001 074*3 PRODUCED BY FORD