Document 9ObjqvQ3peNdBrQ926zLnMye

STOOI 1551. t x*). iiial a oc.vere .* i?* *C -vest v;;a rO in* =5 of ?* mor.ich is been a sun at the prous in ar the -ir.r., . The suti .on of a been i (6). is end igated i 0.017 meters .aus oi a thst ril. In .tiding an i.3* s used. . even eaidea .socing .1 type Ihrocic ted by vorkers .ere the arsenic, i.ydror.ewhat atiy ocs water ; dilute ugh the ie effect T~ ^ * *TXa .e^l. INORGANIC SUBSTANCES of arsine is related to its affinity for the hemoglobin of the red blood corpuscles and the symptoms of acute arsine poisoning re sult from hemolysis of the red blood cells with resulting anemia and jaundice. It has been suggested that arsine is carried un changed to the various tissues by loosely combining with the erythrocytes (13). Fatal termination is frequent Analysis The great importance of arsenic irom a toxicological point of view and the extreme sensitivity of the varioue methods has re sulted in the accumulation of immense amounts of literature devoted to the analyti cal detection and estimation of this sub stance. The conventional Marsh and Gutseit methods which depend on the formation of arsine and its detection are convenient and satisfactory within certain limits. The gold chloride test paper method of Turfitt (14) is a particularly useful test for arsenic. Of the various colorimetric procedures for the micro-determination of arsenic, that of Sandell Is both accurate and sensitive (15). In this method, the material, freed from sub stances that prevent complete evolution of arsine, is so treated that the arsenic is quan titatively evolved u arsine. This, in tun, is absorbed in an acid solution of mercuric chloride containing permanganate and the arsenic thus oxidised to arsenate can be de termined by the addition of an excesa of am monium molybdate-hydraiine sulfate rea gent which yielda molybdenum blue in proportion to the amount of arsenic present. This method is particularly applicable to amounts of arsenic within the range of 1 to 15 micrograms with an accuracy of 5 per cent. Arsenic may also be detected qualita tively by n-ethyl-8-hydroxy-tetrahydroquinoline hydrochloride, which givea a red dish-brown color in spot testa in the presence of ferric chloride (16). The arc spectrum for arsenic Is vsry poor and thero are a number of interfering lines. However, the following lines--2860.5, 2780.2, and 2349.8--are use ful for spectrographic identification. REFERENCES 1. Truhaut. R.: L'amnie s tomcologio i-hatauk. MSthodoa da recherche, causes d'eneur. interpretation des resultau. Science et Vie, Pans. 1933. 2. Sncgireff. L. 3, and Lombard. 0. M.: Arsenic and cancer: Observations m the metailurgic.al industry. Arch. lad. Hy|. and Occupa tional Med. i: 199(1931). 3. Fatrhall. L. T.. and Neal. P. A.: The absorption and excretion oi lead arsenate m man. u. S. Public Ecaith service. Public Health Repts. 33: 1231 (1933). Repr.st No. 1040. 4. Fairhall. L. T.: The solubility e( lead arsenate m body fluids. U. S. Public Health Service, PubUe Health Repts. Si: 163d (1939). Re print No. 9097. 3. Fairhall. L. T~ and Miller, J. W.: A study of the relative toxicity oi the molecular com ponents oi lead anenatt. U. 5. Public Health Service, Public Health Repta.33:1610 (1941). P.cpnnt No. 2302. 6. Fairhall. L. T,, Miller, J. W, and Weaver. F. L.i The ifict oi arsenates on the r.orate oi lead. U. 5. PubUe Health Service, PubUe Health Repts. 33: 933 (1943). Reprint No. 24&S. 7. Watrous. R. M- and McCaughey, M. 3.: Oc cupational exposure to arsenic in the manu facture oi anphenaame and related com pounds. Ind. Med. U: 639 (1943). 3. Bomt'ord. R. R., and Hunter, D.: Arseniuretttd hydrosen poiaoniac due to the action of wa ter on metallic arsenides. Lancet I; 1446 (1932). 9. Nau, C. A., Anderson. W,, and Cone, R. E.: Arsine, stibine, and hydrogen sulfide. Acck dental industrial poisoning by a mixture. Ind. Med IS- 90S (1944). 10. Oerashl. C. U.. Stead. F. M. and Nau. C. A.: Arsme, stibine, and hydrogen suifids. Acci dental generation in a metal refinery. Lad, Med. IS: 361 (1944). 11. BuUner. F. M. R, Rothwell. H. E., Polaek. S. S, and Stewart. D. W.: Chronic arsiae poisoning among workers employed in the cyanide ex traction of gold*, n report of fourteen cassa. J. Ind. Hyg. Toxicol, tt: 111 (1940). 12. Bawlick. C. F,, and Ley, E. B.i Arsine poison ing. Report of n ease. Occupational Med. i: 386 (1946). 13. Levvy, G. A.: A study of arsine poisoning. Quart. J. Expti Physiol. Si: 47 (1947). 14. Turntt, G. E.i Reesat advances in toxicological analysis. J. Phann. and Pharmacol. 3: 321 (1931). 15. SandeU. E. B.i Colorimetric mieredetenainatioa oi arsenic after evolution aa arsine. lad. Eng. Chtm., Anal. Ed.82 (1942). 16. MtUaa. 1.: Organic Reagents in Inorganic Analyas. Blakistoa Co- Phiiadaiphia, 1941. p. 236. ASBESTOS Characteristics Asbestos, amianthus, earth flax, stone ffnx, mountain cork, is a characteristically silky, f.brous mineral, the composition of which varies with its source. The form known as chrysotile is derived from serpentine and is a hydrous magnesium silicate containing from 12.5 to 14 per cent water of crysuUisation. DOW 06837 STOOI1555 By Lav 2nc j "A st. cumu them : centre ] theraj ccmpc many Oustry sst... 20 INDUSTRIAL TOXICOLOGY About 95 per eent of commercial asbestos is tain other minerals of minor importance chrysotile. .Chrysotile has the silkiest and have been shown to produce lung fibrosis, strongest, fiber and can be spun. The fibers asbestos is the only important silicate apart may be as long as 6 inches in length. Asbestoa from tale and mica which does not contain derived from amphibole occurs as a variety free silica and yet produces pulmonary lung of minerals consisting of iron, calcium, and fibrotic changes leading to disability and magnesium with little water of constitution. death. Asbestosis occurs chiefly in industrial The latter type of asbestos consists of short plants where asbestos is fabricated. The fibers and is usually inferior to that derived spinning and weaving of asbestos in com from serpentine. Amphibole asbestos (an* bination with other textiles results in ex thophyllite) while not so suitable for spin* posure of workmen to asbestos dust. The ning is more stable chemically than chryso- long-continued inhalation of asbestos dust tile and more resistant to acids and heat. results in a form of pneumoconiosis. The Canada has been an important source (or primary effect of inhalation of asbestos dust the chrysotile asbestos used largely in the is an interstitial pulmonary fibrosis. On an United States. The Canadian asbestos in* X-ray film the shadows cast by this type of dustry is centered in the Thetford Mines fibrosis resemble ground glass in appearance area of the Province of Quebec. A new and usually extend over the lower portions source for chrysotile type asbestos is a large of the lung fields, frequently being heavier quarry on the eastern shoulder of Belvidere on the right side (2). Unlike silicosis, nodu Mountain in Vermont which was opened in lar fibrosis has not been detected in asbestos the summer of 1944. This deposit is of im workers (3). The fibroecnic action differs portance because it represents the only large from that of silica in that the effects are source of long-fibered chrysotile so far found produced only by long asbestoa fibers while in the United States. Deposits of amphibole the very short asbestos fibers appear to have asbestos are mined in Georgia and North little or no effect. The long fibers apparently Carolina. block the finer bronehioles and produce Industrial Uses fibrotic changes as a result of irritation. A progressive dyspnea, variable cough, sub- Asbestos is an important substance in in sternal chest pains, decreased chest expan dustry and consumption in the United States sion, weakness, emaciation, clubbed finger for 1951 amounted to 796,992 short tons (1). tips, and curved fingernails are the chief Due to its fibrous nature, flexibility and symptoms of asbestosis, as in silicosis. A heat-resistant properties, it is used exten characteristic finding in asbestosis is that of sively for valve packings, gaskets, boiler asbestos bodies in the lungs and in the spu lagging, and pipe covering in industrial tum (4). The so-called asbestos bodies are plants and as friction material in the auto apparently formed only in the lungs and motive industry. A considerable market may be demonstrated microscopically on exists in the building industry for asbestos- sectioning lung tissue or in the sputum. The cement products, heat insulation, and fire core of the body is an asbestos fiber which proofing. The utilization of asbestos for fibers for spinning in the manufacture of asbestos clothing for fire fighting is an im portant use for asbestos. The largest single outlet for asbestos in manufactured products in 1944 was for clutch facings, and next in quantity of output were brake linings. As is surrounded by protein deposits. Unstained specimens are golden yellow or golden brown. They are not stained with ordinary histological stains but may be demonstrated by the Prussian blue staining procedure. The reaction to the fibrous needle in the tissue which becomes manifest in exudate cell in bestos roofing consumed the third largest amount of asbestos in that year. Industrial Injury filtration is accompanied by numerous giant cells containing foreign particles and an in crease of diffuse interstitial connective tissue and fibrosis. While the essential reaction to .The inhalation of asbestos dust .produces asbestos particles is considered to be ehemt- a condition known as asbestosis. While cer cel by many investigators others consider the DOU 06838 STOOI1556 f \ INORGANIC SUBSTANCES 21 pathogenesis oi the disease to bo tncchani- samples taken from the air of weaving fac cal to) m nature. For instance, the investi tories. The index of refraction being only gations oi Vonvaid and his associates (6) slightly greater than that of Canada bal ladi.-atc that the mode oi action oi the long sam, the relief is low. Other forms of as asbestos fiber is mechanical rather than bestos than chrysolite have somewhat higher chemical in nature. When the lungs are ex indices of refraction. Extinction is parallel amined by the naked eye aiter death, they except in the ease of tremolite which has arc large and densely fibrotic. Often the lung oblique extinction. The birefringence of is completely adherent to the chest wall and, chrysolite is moderate n, - n, = 0.013. The in advanced eases, to the diaphragm with maximum interference color is bright yellow the formation oi a thick and extremely dense of the first order. The air sampling of asbes layer oi fibrous tissue. Four main complica tos dust both by the impinger method and by tions and sequelae oi pulmonary asbestosis the electrostatic precipitator method is dis are purulent bronchitis, bronchial pneumo cussed in detail by Fehnel (13). nia, pulmonary tuberculosis, and emphy sema 17). Several cases oi asbestosis have been reported which progressed to a fatal termination with heart failure and without evidence oi infection or other complicating disease |8). Any appreciable decrease in the amount of asbestos dust will cause a de crease in the incidence and severity oi as bestosis i9). In a recent study of 40 cases oi asbestosis at necropsy, Lynch and Cannon UO) found support for the belief that fibro sis does not progress indefinitely after cessa tion of exposure. It would appear that ii the dust concentration in asbestos factories can be kept below 5 million particles per cubie foot, new cases of asbestosis would not arise >2).Cartier ill) has found cases of asbestosis oniy in those employed for at least 14 years and exposed to air containing at least o million fibrous particles varying in length from 10 to 230 microns per cubic foot of air. Doll u2) has concluded from a study of 105 necropsies oi individuals employed at an asbestos works that lung cancer is a spe cific hazard oi asbestoe workers. Analysis While the analysis of asbestos dust as as aerial contaminant is not of particular im portance, its microscopy and above all the evaluation oi the number of partieles per REFERENCES 1. Bowles. O., tad Batwgiaa. F. M.; Asbestos. Minerals Yearbook 1931. U. S. Bur. Mines, Washington. D C.. 1934. p. 167. 2. Dreeteea. W. C., DsUaVaile. J. M.. Edwards, T, I.. Miller. J. W,, and Sayers. R. R,: A study of asbestosis in the asbestoe textile industry. U. S. Publie Health Service, Public Health Bull. No. 241 (1938). 3. Sayer*. R. R.. and Dreesaco, W. C.: Asbestosis. Am. 3. Public Health (9: 203 (1939). 4. Laaxa. A. J.: SiUcoais and Aihesmaia, Oxford Uwv. Pme. New York. 1938. 3. Noro. L.: Histology of asbestosis. Acta Pathol. Microbiol. Scant!.. Kobenh. <3: 33 (1948). 6. Vonvaid. A. J., Durkaa. T. M- and Prat. P. C.: Experimental studies of asbestosis. Arch lad. Hyg. tad Occupauoaai Med. 3; 1 (1931). 7. Gloyns, S. R-, and Meriwether. E. R. A.: As- bestoe. Occupation and Health Suppl. In ternational Labour Oflea, Geneva. 1938. 8. Laaia. A. J. and Goldberg, J. A.: Industrial Hygiene. Oxford Umv. Press. New York, 1939. p. 387. 9. Pag*. R. T., and Bloomfield, J. J. A study of duet control method* m an asbestoe fabri cating plant. U. S. Public Health Semes, Public Health Rests, it: 1713 (1937). 10. Lynch. K. M- and Cannon. W. M., Asbestosis. Analysis of forty necropeied esse*. Diseases of the Chest li: 874 (19a). 11. Certier. A contribution to the study of asbestosis. Arch, maladies profess. 10: SSB (1949). IX Doll. R.: Mortality from lung canear in as bestos worker*. Brit. J. Ind. Msd. it: 81 (1933). 13. Fshnsl. J. W.: Air stapling of asbestos dust: comparison of impmgsr and tlsctroatauc pre cipitator method*, ud. Mad. 3: Ind. Hyg. Sscv i: 3 (1940). cubic foot of air is of paramount importance. Air samples may be secured by the impinger BARIUM method using 23 to 30 per cent alcohol as a collecting medium and dust counts made by Characteristics the usual method. Microscopic examination Barium, Ba, atomic weight 137.36, denrity of the dust reveals typical asbestos fibrous 3.S, melting point S30* C., and boiling point particles which may be accompanied also by 1140* C., is a yellowish-white, slightly lus cotton or other textile fibrous materials in trous, soft metal which is somewhat malle- DOU 06839