Document rexgk8K7nYYONKLdQmxrK5e6e

! ' VsV - 38 - son."jv*. ^saBmeprjc.incgr.rKanrBdrndr.ectikeCcAtx:cocnrcoi EffcaCsEbKeLsAtcoi-srcDinCBaEiere,tKefcocoEdiB. KDECEEanCdEl ewractceer Samp)i ng * serious obstacle in the study of the interaction between potential toxic substances in the environment * like asbestos - and man is that the quantities of pollutants fluctuate in space and time. Keeping the latter factor in mind, it is the purpose of proper sampling techniques to arrive at a quantitative estimate of the exposure which results in an increase of the "body' burden*' of t.he general population. On the basis of present knowledge on the biological effects of asbestos it primarily seems that the average exposure over a period of time is of interest. This simplification means that for an inventory of exposure levels a large number of samples (e.g. 8 hrs. samples) taken consecutively can be added together (averaging in time). When the presence of asbestos in ambient air, water and food is investigated, it is often preferable to sample syn chronously in several places in the vicinity following the same sampling procedure {avc-raging in space). Tor the investigation of the arbestos content of soil it will be, in general, sufficient to investigate a large nurthcr of samples from different locations since time fluctuations re in rv.cny cases of lesser importance. Though sampling is of primary importance in the described investigations on)^_yery gc:,t-ra) guidelines on sampling procedures can be given at this stage. This combined with the 1ackofstandard!.sation of analytical proce dures is the reason that the results of individual investigations can only e compared with reservation. lor the determination of the at*b*Ktos content, of afbsand water the solid content Ss in genera) separated fiom the carrier-mcdit?*. true tc- the small sire of the asbestos fibres in ambient air and water the separation methods which can bo used arc Jn practice limited (Air Sampling Instruments 197?). For air they are: high efficiency filoaticn (r-.wevr., et al 1974, Nichol- fiHii & Nr tofC.' ?.<* rif$ Vk h' cr n* rivni*: y. v: fu<rc iig. :v-i I 7hi M>*C 72 Sfttr fi, J77 tt. tzre f &o S tfiQfi P '2> frzm i ;*ise S001 0 V 3 } PRODUCED by ford