Document EdYgp9RNE4LpxYngX9D2eYxzg

AwH .asbestos Symposium Bell Laboratories e*t* April 26, 1979 ':o- . Vicki R. Coh"a On April 9, 1979, 1 attended an ACGIH Symposium on techniques for evaluating airborne asbestos dust. After some opening remarks by David M. Trayer, Chairman ACGIH, the objectives of the program were discussed by James S. Ferguson of NIOSH, the program chairman. 'The crogram aims were to discuss the following: (1) Identification of asbestos; finding a practical, cost-effective techr'ique. (2) The MOSH method, an evaluation not identification technique. (3) Methods of analysis now in use. (d) Asbestos in schools (5) Insulators in industry, hair dryers, etc. Speakers scheduled to speak in the morning included Walter C. McCrone, McCrone Research Inst., Dr. Voeiker A. Mohnen and Mr. Roger Cheng S .C .R.Y. ," Br." Eric Steel, N.B.S., Willard Dixon, OSHA, Ian Stewart, McCrone, and-Steven Bayer and Dick Coupell, fflOSH. Valter McCrone-spoke about optical techniques. He claimed that the MZD5K procedure is good, bpc must be refined, so as to discriminate between asbes tos- and otherfibers. He discussed dispersion staining in detail. . , . lah-Stewart stressed the importance of crystallographic identification for distinguishing asbestos from nonasbestos material. He claimed o that the SEM is not able to detect fibers less than 3Q0A in width. Irit Steele of the National Bureau of Standards discussed the use of the analytical electron microscope. With this technique resolution ant contrast as well as identification of serpentine from amphibole varieties may be accomplished. Small fiber morphology may be seen using selected area x-ray diffraction (SASD) as well as chemical cimposition using the electron diffraction pattern (O)S). Although 51" car. see and identify most fibers, the polymorphs of the same saroentine mineral (Le., antiguerite, chrysotile), can not be d.i s tier-i shed. SEM is also quite costly, and a standardized techr.irve and practical time problems must be resolved. CONFIDENTIAL 003873 LLz.< Coupe 11 from HIOSH has developed a spot test for identifying as res cos bulk.. The test is actually a screen for the presence of ttatr.e siurc. Tc- date, there have been no false negatives from 150 settles tester. A copy of this relatively simple screening test is *i Hard Di-xcn, 03HA Analytical Lab, spoke about quick tests which could be dor.e in the field to readily identify whether asbestos is present, rone examples he gave were that fiberglass melts and makes a crinkling noise. Fiberglass is also easier to grind with mortar and pestle than asbestos. Vcelker Mohr.en's main topic of discussion was the importance of describing the relationship between the mass of asbestos dust to the fibers present. He stressed that an adequate fiber size distribution relating particle size to mass is of great importance when determining health effects from exposure to airborne fibers. An EPA round robin experiment was conducted in which seven well known laboratories were given the task of analyzing the same dir filter sample. Each of the laboratories came up with different results. Mohnen stressed that some means of standardizing asbestos fiber determinations was necessary. If these highly reputable labs showed such disagreement, what kinds of results car. we expect fron other labs lacking in their expertise. panel discussion with the various speakers was held in the afternoon, chaired by Benjamin Levadie, State of Vermont. He began the discus sion by asking for an honest definition of asbestos. He also asked the audience to consider which forms of asbestos were most hazardous, serpentine or amphibole. Although amphibole is known to be vary hazardous, this variety comprises only 5% of the asbestos which is used. The serpentine variety whose health effects are not entirely understood caamrises 95% of the asbestos which is used. Questions then came -from the floor concerning the rational for the current aspect ratio used forfiber counting. A suggestion was that all physiologically active fibers ought to be regulated. rach panel .member was then asked to comment on which analytical technique is best and how it should be standardized. McCrone commented that the problems are not with the methods, but vitn ,the analysts. He claimed that an optical crystallographic method was the only way to determine the crystallographic mineralogic species. Mohnen didn't recommend any technique and wished to leave the standard ization of methods to Willard Dixon. Cixor. made the recommendation that standard asbestos fibers for calibration purposes be made available through KBS. He suggested field by field instruction and analysis during counting procedures :: standardize the NIQSH method and to employ dispersion staining techniques to verity the crystallographic structure. CONF . a- z <= about: st iticuazmj techniques for crystallographic i'-s-: i : ivstiar. using th~ electron microscope. aycr, '-.'ho runs the N10SH course in phas- contast microscopy ..aimed rhsr \\? has been training individuals to count asbestos ir. a uni form manner since 1971. Whether or not this method ; rest, he has standardized it to the best of his ability. Jim rarguscr.'s comment was that one technique can unt be used for all purposes. The technique to be used should be dependent upon the type of sample to be analyzed. No standardized or best method for the identification and evaluation or airborne asbestos was decided upon at this symposium. All the methods discussed had various drawbacks including time, cost, accuracy, ar.d reproducibility. Several of tne attendees I spoke with, however, mentioned that they would be caking Che HcCrc.ne course in disper3i^.: .`taii'lng. Ir. summary, the symposium was informative both in terms of the di. scussions of the various techniques available for asbestos iden tification as well as the problems associated with those techniques. Hvever, those problems were not resolved. lH-7585-''RC-rIh .1 . w . - Test fcpy to (:/att) . L. Beach - ATT N. .J . BeCapua J. M. Degen. Stone, M.D. Deitchnan - BTL D. G. Hodgkins J. Schreibeis G. M. V.'ilkening N. hood - XVT Vicki R. Cohen C' V- Tv > i i. t\ < *..3 003875 Kr Test for Screening Asbestos (/.?/> C'evpa-// . t. scope a::q- application This colorimetric test is applicable to the detection of magnesium . (IT), and iron (II) from asbestos in bulk samples. These samples include sprayed .on asbestos as v;ell as ceiling tiles. The Kr test is simple and can be readily used in the field to screen for the presence.or absence of asbestos. it. ' principle ; !_ The K2 test is. based upon the formation of .color .complexes v/ith Mg+2 and Fe+2 released from asbestos. The Mg+2 from chrysotile i^ 'Compl exed with p-nitrobenzeneazo-ci-naphthol. The Fe from crdoiidGlrte and amosite is comp!exed .-with 1, iJD-phenanthroline. A positive test+is indicated by the formation of .colored complex for Mg+4 and/or Fe , and it indicates possible presence of asbestos., : ill: INTERFERENCES ' ' / " The K2 test is a colorimetric, spot test for-Mg+2 and.Fe+2,. and-is not .specific for asbestos. , The butk samp!e may contain Fe compounds other than asbestos. Without treating the sample as in the Procedure, the color forming reagent is added directly to the sample. If red color forms, Fe is present as an interference and these samples can be washed with water prior tothe testto eliminate the interference. In the Kr test; plaster (CaSO^) -interference Is removed from the sample prior to the Mg test. S EMSI TTVITY, PRECISTON, AilD ACCURACY ; --- ^ ;~ ;-t , .-A. /with the gl,y.cerineiitr:eai3snt the detection limit'Is -about 2 rog of:.... ..' 'A - pure chryso.til eV;par. test. (I ' , ' T. ;;. , : oy .X tested., "52"sampTeis or~ " .f 7451 v.'ehe correctly identified by the ^ test as. tovwhether asbestos was = present or-absentI,v1Pn1 y: 18Asamjfi es or 26*, gave ifalie pos 1 ti ve- reactions-.- . The-K^iilest^was: accurate in identifying 22 samples that` did:^not> eon- Af^tarnialpltol:.^ #e:K/. test;results were verified: using the transmisslioh-- el ectron microscope. Vf -APPiAP/mrS v T.. if 2.: : 3. 4. ' 5. ; 5. 7. Teflon dish i'icrospatoTa or glass rod Dropping plastic pipet 15 ml disposable plastic bec'c-r 25 mm size 0..8 ym membrane filter 25 r.~; Swfnnex filter holder end ges'-ei ID r,l disposable plastic syringe CONFIDENTIAL 003876 - 2 VH REAGENTS (Reagent''Grade) 1. Phosphoric acid, concentrated. 'i 2. 10 R sodium.hydroxide - Dissovl.e-40 g of NaOH in 100 mL of v/ater. 3; Mg Reagent - Dissolve 1 mg of p-nitroberizeneazo-a-naphthol in 100 mL of 2 N NaOH. Age at least a day. This reagent, is stable over a month. . 4. - Hydrofluoric acid - Dilute.20 mL of HF wit1v20 mL ofiwater. Add. 0.6 mL of concentrated HC1. ; ( s5. ;'Fe Reagent--Dissol ve 2,g .of .'TilOTphenanthroTfnre `in 50 mL of ethanol. This reagent is--stable-over'a^mpnth.y 6. Glycerine, reagent, grade. ic ^Bdublie de-rani-zed-.water,;. . . VII. PROCEDURE A; Magnesium Test ;Hw; '-/: V ., V ' a.'-. -Places small; portion- of ..sample. ;in a:plastic - beaker. b. Add~.5 drops of ^gTyC'enine^a'nd: mix-well, with ^spattfla., x., . Rinse- spatdla.'-wlt-h a^ismall-amount.- of-*Water irfto the .' 3' -tT--''WwV,*-' . beaker. r - -d.' -Foster the^sampTe -ti^ugh^bhe^iltcation ^ssembly^consistr;; - . jfengo f -syrtogs .-attaXfagd tp- the ;jSv;i.nnex -fintef ~hol der r tv .'V'''' '.'"`1''r - > * loaded With a membrane-filter~and<a.. gasket.- ` j . c'* **<se.. Fi1^i^i.ttb-iBifliiBi'a4 of :5:>wasihi'hgs^or . f." 'Transfer.'filter.to .a Teflon dish. | CONFIDENTIAL 003877 3 2. Add a drop of H^po and mix wall fay grinding the sample with a spatula. 4 3. Add 2 drops of 10 fi flaOH and mix well. 4. Add 5 drops of Mg Reagent-and stir briefly. Note any color change. 5. Add 5 more drops of Mg Reagent and observe the final color. 6. A blue color indicates that chrysotilejinay be present. 7. No color change with Mg Reagent indicates the absence of chrysotile. Even though amosite contains magnesium, this test does not produce the blue color. The iron test would produce a positive reaction indicating the presence of asbestos. 8. Check for Mg interference as in Section III if positive result is obtained. 8. Iron Test 1. Place a small portion of sample on a Teflon dish. 2. Add a drop of HF solution and nix well. 3. Add 5 drops of Fe Reagent and observe the development of red color. 4. The red. color indicates-that amosite or crocidolite may be present. 5. Check for iron interference as in Section III. C. flotes If both tests give-negative responses there is a low probability that any asbestos is present. Once the presence of magnesium and/or iron is indicated, further analysis if needed is done in the lab oratory to confirm, identify the type, and quantitate the percentage of asbestos. CONFIDENTIAL oo:s?8 Till. REFERENCE 1. Caution: Asbestos Dust. A scriptographic booklet by Channing L. Bete Co., Inc., Greenfield, "ass. Prepared in cooperation vn th U.S. SHEW, PUS, CDC, National Institute for Occupational Safety and Health, Cincinnati, Ohio (1973). 2. Fritz Feigl; Spot Tests - In Inorganic Analyses. Translated by Ralph E. Oesper. 5th Edition. Elsevier Publishing Company, Amsterdam. (1958) p. 225-227. 3. Walter S. Kim, James W. Carter. II, and Richard E.Kupel: Quick Screening-Test for Asbestos {Yr Test). U.S. CHEW, PHS, CDC, NIOSH, Cincinanti, Ohio. To be pubisihed in AIHAJ. Walter S. Kim Richard E. KupeT U.S. Department of Health, Education, and Welfare Public Health Service Center for Diseasc.Control Rational Institute for Occunational Safety and Health Di..sion of Physical Sciences and Engineering Measurement Support Branch Cincinnati., Ohio 45225 ; April ,197,9 WFfDlNTlAt 003879