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S I think Don Beaman came the closest to suggesting what specifically about these patterns should be used as a method of confirmation. Furthermore, we have always seen a pattern of an amphibole, generally one of the asbestos mineral species and chrysotile. I would like to point out particularly with water and environmental samples that there are probabl* two to three hundred other fibrous minerals by your definition, all having electron diffrac- tion patterns. Dr. Zussman brought up the point yesterday, you need a three-dimensional orientation to know precisely what you are going to get, and that does not get into other problems of defects and so on. What bothers me is, nowhere have I seen anything but pictures in saying that this is different than that and I think, and maybe you have done this, we need a step-by-step procedure for confirmation of the amphibole group or the chrysotile group or something along this line. Then mineralogists can take these and they can say generally you'll get this or you won't get this. Watch out, these mineral species will do the same thing. I have not seen this anywhere and it is rather frustrating to say you need electron diffraction confirmation when you don't know what the step-by-step procedure is to the same degree you have so eloquently done with the sample preparation. ANDERSON: We certainly recognize you have to balance the realities of the analysis in how much time can you really spend in analyzing an electron diffraction pattern from a single fiber. As Sumudra pointed out last spring, if you use a very small camera length you get a large percentage of fibers giving an electron diffraction pattern. They are reasonably characteristic, the amphibole pattern is reasonable, and certainly the chrysotile stands out. The amphiboles are certainly all very similar; they are all characteristic and there is certainly a judgmental factor involved, although we have compared our judgments on the Duluth amphiboles versus what Beaman published and we get almost the same curve. Our judgment was about the same as Beaman's and I guess that is all you can come up with, and I think that other people will find somewhat the same thing. KRAMER: Let me repeat, because in these cases the amphiboles and the chrysotile have been worked with. There are many other minerals in the environment, such as chain silicates; I'm not saying there is a unique method, but I think we need to know as an interim method, if you want to call it that, the procedure by which these are to be confirmed. Then we can go ahead to the next step. ANDERSON: Confirmed as far as identified? KRAMER: As identified by SAED in your 1ab. Then we can go ahead to the next step. ANDERSON: I don't care to confirm halite as halite; I don't care about some other minerals, all I care about is asbestos minerals. P. McGRATH: What I contended, although I can appreciate the problem I have with the development on an interim method, I think we have to begin to realize that all of the analysts who are going to be doing this over the next few years are not going to be an Eric Chatfied or Jim Millette. I think that the EPA and other groups that are going to do an awful lot of this testing, and in all probability will end up setting the standards for the rest of the country, should look into other methods, and I agree with Jim McAlear that we have abused scanning electron microscopy and it's not going to be a panacea or an answer for all these things, but I know from my own experience and the experience in other laboratories that you can get reasonable counts and reasonable chemical information from the scanning electron microscopy, and in all probability quicker and at much reduced cost than you can with your method. You mentioned somewhere that this is a sort of a quick and dirty method; it is not a quick or dirty method. ANDERSON: It is not a quick or dirty method. McGRATH: It's a long and involved tedious thing, and the operator has to be an excellent operator to get the kind of results that you got, with Jim Millette and Phil Cook. ANDERSON: Well I think the whole crux of the matter is whether the SEM with the conventional, lanthanum hexaboride, or field emission source can indeed detect two hundred angstrom wide fibers and also give sufficient x-ray data to identify that fiber as an amphibole or chrysotile. 375 2063105166

NOTE: The following was a note sent following the meeting and was not part of the verbal discussion at the end of this paper. p. JACKSON: Dr. Anderson could you comment on the areas which may prove problematic and the areas requiring, particular attention in using your proposed Analytical Methodology for determining asbestos in water. ANDERSON: The following areas appear to me to be the major problems to be overcome in determining asbestos in water. 1) Assuring that you have a representative sample. 2) Contamination, both during the sampling process and in the laboratory. 3) Filtering the sample in such a manner that the particulates deposit in a near- random distribution and without over-loading the filter. 4) The presence of a large amount of extraneous particulate matter in relationship to the amount of asbestos. 5) Dissolving the filter material without loss or movement of the asbestos fibers. 6) The identification of amphibole asbestos fibers. 376