Document 4J92jXjJ1MGnrXKQKqBRLnRpe

tuOtKt ACS IB Asbestos Symposium WAIP^Sffiollwr ATT-339 Bel Laboratories f a.t. April 26, 1979 from: Vicki R. Cohen On April 9, 1979, I attended an ACGIH Symposium on techniques for evaluating airborne asbeatoa 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 program aims were to discuss the following: (1) Identification of asbestos; finding a practical, cost-effective technique. (2) The NIOSH method, an evaluation not identification technique. (3) Methods of analysis now in use. (4) Asbestos in schools (5) Insulators in industry, hair dryers, etc. Speakers scheduled to speak in the morning included Halter C. McCrone, McCrone Research Inst., Dr. Voelker A. Mohnen and Hr. Roger Cheng S.U.N.Y., Dr. Eric Steel, N.B.S., Willard Dixon, OSHA, Ian Stewart, McCrone, and Steven 3ayer and Dick Coupell, NIOSH. Walter McCrone spoke about optical techniques. He claimed thac the NIOSH procedure is good, but must be refined so as to discriminate between asbestos and other fibers. He discussed dispersion staining in detai 1. Ian 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 300A in width. Eric Steele of the National Bureau of Standards discussed the use of the analytical electron microscope. With this technique resolution and 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 (SAED) as well as chemical composition using the electron diffraction pattern (EDS). Although SEM can see and identify most fibers, the polymorphs of the same serpentine mineral (ie. , antiguerite, chrysotile), can not be distinguished. SEM is also quite costly, and a standardized tech nique and oractical time problems must be resolved. LLft 001631 2- Dick Coupell from NIOSH has developed * spot teat for identifying atbeatoa bulk. The teat is actually a acreen for the pretence of augneaium. To date, there have been no falaa negative* fro* ISO staple* teaced. A copy of thia relatively simple screening teat is attached. Willard Dixon, OSHA Analytical Lab, spoke about quick tests which could be done in the field to readily identify whether arbestos is present. Some examples be gave were that fiberglass aelts and makes a crinkling noise. Fiberglass is also easier to grind with mortar and pestle than asbestos. Voelker Mohnen's main topic of discussion was the importance of describing the relationship between the mass of asbestos dust to the fiber* present. He stressed that an adequate fiber size distribution relating particle size to aass is of great iaportance when deteraining health effects froa exposure to airborne fibers. An EPA round robin experiaent was conducted in which seven well known laboratories were given the task of analyzing the saae air filter saaple. Each of the laboratories caae up with different results. Hohnen stressed that soae means of standardizing asbestos fiber determinations was necessary. If these highly reputable labs thoved such disagreement, what kinds of results can we expect from other labs lacking in their expertise. A 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 amst hazardous, serpentine or amphibole. Although amphibole is known to be very hazardous, this variety comprises only 5Z of the asbestos which is used. The serpentine variety whose health effects are not entirely understood comprises 95Z of the asbestos which is used. Questions then came from the floor concerning the rational for the current aspect ratio used for fiber counting. A suggestion was that all physiologically active fibers ought to be repilated. Each panel member was then asked to comnent on which analytical technique is best and how it 3hould be standardized. HcCrone commented that the problems are not with the methods, but with the analysts. He claimed chat an optical crystallographic method was the only way to determine the crystallographic mineralogic species. Hohnen didn't recommend any technique and wished to leave the standard ization of methods to Willard Dixon. Dixon made the recommendation chat standard asbestos fibers for calibration purposes be maue a/ailable through MBS. He suggested field by field instruction and analysis during counting procedures co standardize Che MIOSH method end to employ dispersion staining techniques to verify the crystallog~aphic structure LLA 001632 3 Ian Stwart (poke about standardizing techniques for crystallographic identification using the electron microscope. Steven Bayer, who runs the HIOSH course in phase contest Microscopy claimed that he has been training individuals to count asbestos in a uniform manner since 1971. Whether or not this method is best, he has standardised it to the best of his ability. Jim Ferguson's comment was that one technique can not be used for all purposes. The technique to be used should be dependent upon the type of saiq>le to be analyzed. No standardized or best method for the identification and evaluation of airborne asbestos was decided upon at this symposium. All the methods discussed had various drawbacks including time, cost, accuracy, and reproducibility. Several of the attendees 1 spoke with, however, mentioned that they would be taking the McCrone course in dispersion staining. In sussury, the symposium was informative both in terms of the discussions of the various techniques available for asbestos iden tification as well as the problems associated with those techniques. However, those problems were not resolved. MH-7885-VRC-rlh Att. K2 Test Copy to (w/att) R. L. Beach - ATST N. J. DeCapua J. M. Degen R. W. Stone, M.D. R. Deitchman - BTL D. G. Hodgkins W. J. Schreibeis G. M. Wilkening hood - NYT ' r kj ^ Vicki R. Cohen LLA 001633 CoVifn K? Test for Screening Asbestos {D/c>1 I, SCOPE AND APPLICATION AJ/CSM^ This colorimetric test Is applicable to the detection of magnesium (II) and Iron (II) from asbestos In bulk samples. These samples Include sprayed on asbestos as well as celling tiles. The K* test is simple and can be readily used in the field to screen for the presence or absence of asbestos. II. PRINCIPLE The jest Is based upon the formation of color complexes with Mg++2 and Fe+2 released from asbestos. The Mg+' from chrysotile Is compl exed with p-nitrobenzeneazo-a-naphthol. The Fe+* from crocldolite and amoslte Is complexed with 1, 10-phenanthroline. A positive test+is Indicated by the formation of colored complex for Mg+^ and/or Fe c. and It Indicates possible presence of asbestos. III. INTERFERENCES The test is a colorimetric spot test for Mg +2 and Fe+^, and Is not specific for asbestos. The bulk sample 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 to the test to eliminate the interference. In the K2 test; plaster (CaSO^) Interference Is removed from the sample prior to the Mg test. IV. SENSITIVITY, PRECISION, AND ACCURACY With the glycerine treatment the detection limit is about 2 mg of pure chrysotile per test. - .3 % - From the total of 70 various field samples tested, 52 samples or > 74% were correctly identified by the Kr test as to whether asbestos was present or absent. Only 18 samples or 26% gave false positive reactions. The Y. test was 100% accurate in identifying 22 samples that did not con tain asbestos. The test results were verified using the transmission electron microscope. V. APPARATUS 1. Tcfl oni dish 2. Mic:ros patula or <glass rod 3. Droppi ng plastic pi pet 4. 15 ml disposable plastic beaker 5. 25 mn size 0.8 pm membrane filter 6. 25 mm Swinnex fi Iter holder and gasket 7. 10 nL disposable plastic syringe U-A 001634 2 VI. REAGENTS {Reagent Grade) 1. Phosphoric acid, concentrated. 2. 10 N sodium hydroxide - Dlssovle 40 g of NaOH In 100 mL of water. 3. Mg Reagent - Dissolve 1 mg of p-nltrobenzeneazo-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 with 20 mL of water. Add 0.6 ml of concentrated HC1. 5. Fe Reagent - Dissolve 2 g of 1,10-phenanthroline In 50 ml of ethanol. This reagent Is stable over a month. 6. Glycerine, reagent grade. 7. Double de-lonlzed water. VII. PROCEDURE A. Magnesium Test a. Place a small portion of sample In a plastic beaker. b. Add 5 drops of glycerine and mix well with a spatula c. Rinse spatula with a small amount of water Into the beaker. d. Filter the sample through the filtration assembly consist ing of syringe attached to the Swinnex filter holder loaded with a membrane filter and a gasket. i e. Filter with minimum of 5 washings or abodt 50 mL of water. x f. Transfer filter to a Teflon dish. LLA 001635 4 3 2. Add a drop of H^po and mix well by grinding the sample with a spatula. 3. Add 2 drops of 10 N NaOH and mix well. 4. Add 5 drops of Hg 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 chrysotile may be present. 7. No color change with Mg Reagent indicates the absence of chrysotile. Even though amoslte 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. B. Iron Test 1. Place a small portion of sample on a Teflon dish. 2. Add a drop of HF solution and mix well. 3. Add 5 drops of Fe Reagent and observe the development of red color. 4. The red color indicates that amoslte or crocidolite may be present. 5. Check for iron interference as in Section III. C. Notes 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 inaiv.ated, further analysis if needed is done in the lab oratory to confirm, identify the type, and quantitate the percentage of asbestos. LLA 001636 VIII. REFERENCE 4 1. Caution: Asbestos Dust. A scrlptographlc booklet by Channlng l. Bate Co., Inc., Greenfield, Hass. Prepared In cooperation with U.S. DHEW, PHS, CDC, Natioi.al Institute for Occupational Safety and Health, Cincinnati, Ohio (1973). 2. Fritz Felgl: Spot Tests - In Inorganic Analysis. Translated by Ralph E. Oesper. 5th Edition. Elsevier Publishing Company, Amsterdam. (1958) p. 225-227. 3. Halter S. Kin, James H. Carter- II, and Richard E. Kupel: Quick Screening Test for Asbestos ()c Test). U.S. DHEW, PHS, CDC, NIOSH, Clnclnanti, Ohio. To be publslhed in AIHAJ. V Halter S. Kim Richard E. Kupel U.S. Department of Health, Education, and Welfare Public Health Service Center for Disease Control National Institute for Occupational Safety and Health Di. .slon of Physical Sciences and Engineering Measurement Support Branch Cincinnati, Ohio 45226 April 1979 LLA 001637