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CS Cummingtonite FIBERS Figure 5. Corrected intensity ratios for analysis of 64 asbestiform fibers from Labrador (figure 2a). Figure 6 shows two examples of the analysis of different locations on the same fiber for the Labrador cummingtonite-grunerite sample. Once again there is a much smaller variation (<10 percent) of intensity ratios along an individual fiber with the exception of one location which showed an extremely high Fe/Si ratio. This very large ratio may be due to surficial Fe-oxide, although there was no anomalous electron density visible. N O 29 w ~ 0 w ~+

0 F- Mn N Z Ti ~ z w ~ K 0 ~ ~ Na H a w a w Ca 0200 ar Mg~ 0180 J a /S' 0160 F- 0200 a F~ 0.750 ~ S i 0.700 w 0:650 J w CUMMfNGTONITE ~ ' • • • • • • • • ~ • c-~ • 0 0 • 0 _0 ~ ~ Mg 021 019 51i 017 J 0.15 a ~ Z F e 1.0 w i Q9 w Q8 J w 0.7 ANALYZED S POTS (CUMMINGTONITE FIBERS 16rm. dia. 0.4rm.) CUMM I NG TON ITE 19.6 ._..--.r i J ANALYZED SPOTS (CUM MING TONI T E FIBE RS I6ym. dia. 0.2rm.) Figure 5. Variation in intensity ratios for analyzed spots along two asbestiform cummingtonite-grunerite fibers from Labrador. I 0 30

There appear to be two possible reasons for variations in areal intensity ratios. There can be a real variation in the composition of individual fibers in an apparently homogeneous phase, and/or the differences can be due to x-ray adsorption and secondary radiation especially from Fe in these samples. The fact that analysis on spots on a specific fiber gives an intensity variation less than 10 percent (with one exception in 200 analyses) compared to a 30-50 percent variation in bulk is strongly suggestive that the difference in the two' variations (20-40 percent) is the approximate absolute variation in intensity ratio due to compositional variation that exists in these samples. If the coefficient relating intensity ratios to compositional ratios is not dependent upon other factors, one would anticipate a real variation in fiber composition of 20-40 percent maximum for the major elements. One assumes generally that the composition of fibers within a relatively pure mineral- ogical phase is reasonably constant in composition. This assumption must be tested by detailed analysis of many fibers within a specific sample. Conclusions It appears that asbestos morphology differs from other elongate acicular-fibrous minerals and from environmental exposures in the largest percentile group. Therefore, the entire size distribution should be characterized before carrying on toxicity studies. The composition of fibers within a well characterized sample may vary in composition. Hence analysis on individual fibers must always be carried out. Finally the health significance of fibers other than asbestos should be studied. Primary cytotoxicity and mutagenicity testing of hydrated silicates, anhydrous silicates and non-silicates may well provide clues for more extensive studies. Work supported in part by Inland Waters Directorate, Environment Canada. Microscope analytical work by 0. Mudroch, and field work by R. Marttila are gratefully acknowledged. References [1] American Geological Institute, Glossary of Geology, Washington, D.C., 1972. [2] Beaman, D. R. and File, D. M., Quantitative determination of asbestos fiber concen- trations, Anal. Chem., 48, 101-110, 1976. [3] Borschchevskii, Y. M. and Konikova, T. S., Apatite and apatite-nepheline dust, Nauch. Tr., Leningrad Inst. Usoversk. Vrachei, 115, 108-116, 1973. (Chemical, Abst: 080: 078900). [4] Burilkov, T. and Michailova, L., Sepiolite content of the soil in regions with endemic pleural calcifications, Int. Arch. Arbeitsned, 29, 95-101, 1972. [5] Buritkov, T., Michailova, L., and Babadjov, L., Amphibole asbestos in the soil and its significance for the endemic occurrence of pleural plaques, Zh. Gesamte Hyg. Grenzgeb, 18, 802-809, 1972. (HEEP:74/02556). [6] Campbell, W. J., Blake, R. L., Brown, L. L., Cather, E. E., and Sjoberg, J. J., Selected silicate minerals and their asbestiform varieties, Bur. of Mines Info. Circ. 8251, 1977. [7] Champness, P. E., Cliff, G., and Lorimer, G. W., The identification of asbestos, J. of Microscopy, 108, 231-249, 1976. [8] Cralley, L. J., Inhalable fibrous materials. in H. A. Shapiro (ed), Pneumoconiosis, Oxford U. Press, 1970, p. 70-74. ~. 0 A ~ W W

[9] du Toit, R. S. J., Dust in South African asbestos mines and fiberizing plants, in reference 8, p. 13-17. [10] Hunter, B. and Thomson, C., Evaluation of the tumorigenic potential of vermiculite by intrapleural injectiDn in rats, Brit. J. Indust. Med., 30, 167-173, 1973. [11] Koshi, Kimiko, Hayashi, Hisato, and Sakabe „ Hiroyuki, Cell toxicity and hemolytic action of asbestos dust, Ind. Health. 6, 69-79, 1968. [12] Kramer, J. R., Asbestos: Nomenclature, occurrence and redistribution in water, in Drinking Water and Health, U.S. Nat. Res. Counc., 1977 (in press). [13] Mikhailova-docheva, L., Hygienic evaluation of the mineral composition of soils in regions of the People's Republic of Bulgaria marked by the revelence of endemic pleural calcifications, Gig. Tr. Prof. Zabol., 16, 30-33, 1972. (HEEP: 73/04741). [14] Owinski, J., Effect of dust pollution and thermal microclimate on the incidence of chronic non-specific diseases of the respiratory system with regard to the gypsum workers industry in Gacki, part IV, Radiographic results and symptoms of chronic bronchitis, Przegl Lek, 32, 265-268, 1975. (MEDLINE). [15] Pott, F., Huth, F., and Friedrichs, K. H., Tumorigenic effect of fibrous dust in experimental animals, Environ. Health Perspect., 9, 313-316, 1974. [16] Pylev, L. N. and Iankova, G. D., Carcinogenic activity of magnesia arfvedsonite administered intrapleurally to nonbred rats, Vopr. Onkol., 21, 71-76, 1975. (TOXBIB: 75/104450). [17] Schnitzer, R. J. and Pundsack, F. L., Asbestos hemolysis, Environ. Res., 3, 1-13, 1970. [18] Spiel, S. and Leineweber, J. P., Asbestos minerals in modern technology, Environ. Res., 2, 166-208, 1969. [19] Webster, I., Commentary, in reference 8, p. 133. [20] Zoltai, Tibor, History of asbestos-related mineralogical terminology, This Proceed- ings, Paper 1. [21] Zoltai, Tibor, Comments on asbestiform and fibrous mineral fragments relative to Reserve Mining Company taconite deposits, Minn. Pollut. Contr. Agen., Minneapolis, 37 p + III append. 1 . 32

SS Discussion C. RUUD: What was the accelerating voltage of your electron beam in all of these microanalyses? J. KRAMER: We tried some studies varying it, but the value we used routinely was 80 kv ' There are a lot of details of these findings on the analytical part which suggest problems. I would be happy to discuss these with individuals. M. COSSETTE: Are you aware of any work with high pressure mercury porosimetry to differentiate between fibrous length groups? KRAMER: No, do you have some data or know of some? COSSETTE: No, I know of some people doing work in the area but nothing published. A. WILEY: Do you use the polarizing microscope, and, if so, do the clino-amphiboles show parallel extinction? KRAMER: Yes, within analytical error, but some of the cummingtonite fibers from Labrador may not show parallel extinction. They may have a small angle (5-10'). WILEY: Your ordinary varieties do, though? KRAMER: Yes, I think that this is a very important point to consider; this apparent optical difference and its significance to fiber morphology. D. BEAMAN: 0.3 pm is not particularly large for an amphibole. I wonder to what extent you feel some of these trends may be due to the difference in the size of your fibers. KRAMER: Yes, there may well be a size factor. 0.3 pm width is at the threshold of size effect upon intensity ratios according to your study published in Analytical Chemistry. F. MUMTON: I'd like to ask you about your ion exchange measurements of these two types of materials; you didn't show any data, but yet you say there are differences. What range are you talking about? What did you do? KRAMER: First of all, the ion exchange differences will depend upon the composition of the material. We worked mostly with cummingtonite from Labrador. What we are using basically are these minerals (see figure 2) as an exchange medium to compete against a copper-organic ligand. The procedure is analogous to an ion exchange column but we are using the minerals. We calibrate the system against known associations such as copper- glycine. We carried out the analyses using equidimensional, fibrous and asbestiform varieties and found little differences in conditional stability constants for the different varieties of the same composition. In addition, the exchange capacities appear to be very similar and typical of all silicate minerals (about 3-4 micro-equivalents/meter2). W. EISENBERG: Have you modified your definition of a mineral species as a result of the data you've obtained? KRAMER: No, you noticed I didn't give any definitions. I just quoted other people. Seriously, I am trying to point out that there are either analytical problems or variations in composition, or both, at the micrometer scale of a fiber. See Science, 198, 359-365 for some possible reasons. 33 1 N 0 A ~ Ln