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INDUSTRIAL DUST Hygienic Significance, Measurement and Control PHILIP DRINKER, S.B., Ch.E. Professor of Industrial Hygiene. Harvard School of Public Health THEODORE HATCH, B.S., S.M. Instructor tn Industrial Sanitation. Harvard School of Public Health and Harvard Graduate School of Engineering CD o CJ o CHAPTER II EFFECTS OF DUSTS AND FUMES UPON MAN Exposure to dusts can produce four distinct types of disability: (1) the pneumoconioses, such as silicosis and asbestosis, are caused only by dust inhalation; (2) toxic dusts like lead, man ganese, and cadmium can produce their effect as the result of RIGHT BROMOiUS UPPER LOBE RIGHT l UNS~ BRONCHIAL *( ii,RAMUS TO ,r UPPER LOBE ` EPARTERlAlf-Stf* rXft! BRONCHIAL---- RAMUS TO MlDOLE LOBE m/ODlE-S d : uBf ; BRONCHIA l\ RAMUS TO LOWER I LOBE LOWER LOBE- _ TRACHEA LEFT BRONCHUS : 1 < BRONCHIAL RAMUS'- 'x70 Loae-^-;; 9^.''UFFER L0BE7j __ ______________________ ______ " __ '-^-'hJAWER lobe Tig. 10.--Lunci. bronchi, and trachea. (Afltr Sobetta and McMvmcA.) either breathing or swallowing dust; (3) metal-fume fever is a temporary malady resulting from inhaling certain metallic oxide fumes; and (4) tlir allcrgir reaction or protein poisoning, as typified by hay fever, i> the direct result of breathing pollen and other organic substances. In all four cases dust inhalation may be the sole cause of disability; only in the case of toxic dusts is there another mode of entrance. Respiration and Dust Inhalation. The lungs arc noiisvmmctrica! bilateral structures encased in a rather elastic cavity, 20 7)riru{u>- t //'/<:/ C/1 --I o EFFEl the chest, ant ^3 through the tri ^ or lobes and tl ~ per cent larger In the norm diameter and lu cartilage which givi the approximate lev< the bronchi and the lead to the terminal as result of inspirai blood and air takes ] cells and carbon dio: The amount of ai with the task perfo rates at which an at Table 1. TaBI* 1.--OXTGEH COI Ratting in bed Sitting............... Standing............ Walking 2 m.p.h. Walking 4 m.p.h Slow run............ Maximum exertio 1 Altar Handaraon and Ha*; The ordinary indiv per minute, the higl such as long-distance The inspiratory an but practically we n: required for & cornplc pauses that occur at Thus with minute vo at the rate of 100 luci 396410 1 II 'i FUMES UPON MAN ur di.-linct type? of disability: silicosis and asbestosis, are 2) toxic dusts like lead, man? their effect as the result of LEFT BRONCHUS BlfOHCHIAL RAMUS' ^. TO UPPER LOBE ''umu LOBE \ BRONCHIAL HA HUS'1 TV ;LONER LOBE I C--'-tnWEK lobe {After SoOoUa and AfcMurruA.) t; (3) metal-fume fever is a haling certain metallic oxide m or protein poisoning, as : result of breathing pollen .11 four cases dust inhalation ; only in the case of toxic .nee. i. The lungs are nonsymi in a rather elastic cavity, EFFECTS OF DUSTS AND FUMES UPON MAN 21 the chest, and they communicate with the nose and mouth through the trachea or windpipe. The left lung has two divisions or lobes and the right lung ha? three; the right lung is about 12 l>er cent larger than the left. In the normal adult, the trachea is a tube some 1 to 2 ent. in diameter and 10 cm. long (Fig. 10); it is fortified with ringlike cartilage which give- it a strong and inelastic character. At the approximate level of the fourth rib, the trachea branches into the bronchi and these in turn subdivide into bronchioles which lead to the terminal air sacs or alveoli. It is in the alveoli that, as result of inspiration and expiration, gas exchange between blood and air takes place. Oxygen is taken up by the red blood cells and carbon dioxide is given off. The amount of air breathed and the oxygen consumed vary with the task performed and with the individual's size. The rates at which an athletic man of 150 lb. breathes arc shown in Table 1. TaRi.f. I --Oxyce.v ( iivsnintov a.xd Volcme or Breatmivc dt Man1 Oxygon consumed *t 0C. and 760 Air brcaihcd mm. pressure, liters at 20'C., liters per minute per minute Resting in bed Silting....................... Standing .......... Walking 2 m.p.li Walking 4 rn.p.h Slow run. . Maximum exertion i 0.24 0 30 0 36 0 65 1.20 2.00 3 00-4 00 6 7 8 14 2G 43 GS-100 1 Afur Hcndroit and Haggard U2il. The ordinary individual seldom breathes more than 50 liters per minute, the high rates being limited to trained athletes, such as long-distance runners. The inspiratory and expiratory phases are not exactly alike, but practically we may consider each as taking half the time required for a complete respiratory cycle and we can ignore the pauses that occur at the beginning and end of each inspiration. Thus with minute volume of 50 liters the actual inspiration is at the rate of 100 liter' per minute and momentarily rather high 4 H--/U ST00I30I5 DCS' conclusion regarding :ih-. i- .ilit.lined from a -nigh' mom. Table 2S). :f sputum iia.-il di-charge of pcr.-uti:It has alwnv- hem and i- .sufficiently .sensitive - `>i a respirator (page 2GS). -charge, diluted if necessary, t h>v smearing on a slide and microineincration technique many examination indicates ential if a polarizing micro- technique that the "silialveolar phagocyte of an lily lie demonstrated.'' .ed when samples of 100 ec. is healed in a beaker over iter has been evaporated. are added and the mixture being shaken at intervals; for 1 hr. The residue is cl incinerated. an accurate case history, tion of dusts in sputum, i hi-tory of recent dust suffices for identification ir dark, even black, before dig i- caused by pigmenta'mo'.-cd by treatment with soch as the histologist 'ici'-d. .'.rgc examinationsfordust, -t ot her preventive mea.sKrf-o'lom from dustin both -t o'/d by layman and med' on photographically and my person familiar with ha.- l/een demonstrated. : i I | ' . i , ' ; l I ; I CHEMICAL ASD MINEHAUDGICAL ANALYSIS 165 The dust in phagocytic cells from human sputum wa> studied hy Drinker (G5), who was able to identify several mineral.- in the 'ells and to establish figures of average particle size in phngneyte-. In order to examine du-i in phagocytes, the sputum sample must he fixed when fresh, and it is best to make several slides, some -lained and some unstained. Stains interfere seriously with the miero-eopy of the particles but help one to pick out the dust cells fnnn extraneous matter. Agingof the .sputum results in bacterial action ujKin the cells which destroys their outline, and must Uavoided.1 The cells from silicotics (coal miners) which we have seen recently contained a great percentage of carbon and little else Since there is little difficulty in getting such cells from patients with silicosis or with a history of recent dust exposure, more such examinations might easily and profitably be made. It should be home in mind that the presence of dust cells in human sputum does not of itself prove any lung pathology. This may be a normal finding and often occurs in the healthy city dweller, particularly if he is a smoker. But in the c-a-c of tinindividual with proved dust exposure, the presence of nunicmudust cells in sputum may help in diagnoses. THE IDENTIFICATION OF ASBESTOSIS BODIES For the identification of the "curious" bodies (see Fig. 15, page 33) found in asbestos workers, Stewart (223) employs tinfollowing technique: About half an ounce of sputum is dissolved in an equal quantity of undiluted antiformiu in a wide test tube. This takes from a few minuteto an hour or so. ami is aided by heat (37C. incubator) and gentle agitation. Two or three ounces of water arc then added and the mixture allowed to stand for a few hours or overnight. The bulk of the <ni|K*rnatant fluid is now poured off and the remaining 12 to 15 cc. centrifuged at moderate speed for 10 min. The amount of deposit which conicdown varies in different specimens, but in any case the whole of the supernatant fluid may be poured off by simply inverting the centrifuge tube. The deposit and the trace of fluid which remain are thoroughly ' It is assumed that any person examining the dust particles in sputum or m nasal discharge will familiarize himself with the accepted routine of sputum examinations as earned out in ordinnrv medical diagnoses, lie need observe only the methods of preparing llie specimens and need nol lie mnirninl with bacteriological ur patiiological mailers. ST00 I 30 I 6 1GG tXDt stuial nrsr mixed by means of a line pi/xate and transferred lo an .albuminized slide nr slides. Too much force mu-t iml lie used in the mixing process or at any previous stage in order not in disintegrate any dumps of asbestos bodies which may be present. As a rule the whole deposit from half an ounce of sputum may lx; spread over an area of 1 sq. in. of a microscope slide, or less, and in any case a thick him is desirable. After thorough drying on a hot plate and final fixation over a Bunsen, the film is very gently washed in water, dried and mounted in Canada balsam. The washing in water must lx: done with the greatest care, as, in spite of the albuininiiation of the slide, the film is very easily detached, especially if it is thick. After washing and drying, the film may be treated with ferroeyanidc of jKitassium and hydrochloric acid to demonstrate the Prussian blue reaction given by the bodies. It i.~ then dried and mounted in balsam as before. Alternatively the centruuged dejxisit may be covered with a small quantity of a 0 per cent solution of ammonium sulfide, when the bodies are colored black. No |x-ciai staining is required, however, as the natural greenish yellow. gulden, or brown eolor of the bodies renders them sufficiently conspicuous even under the low power. My practice is to examine films with the Uin. objective and 10X ocular, confirming the presence of asbestos bodies with the i-in. objective. It is necessary to cleanse thoroughly all test tubes, centrifuge tubes, and pipettes alter use; otherwise there is a risk of contamination of sub~cquent .'I'ccwucn? from a |>mIi\c sputum. Asbestos hollies are demouMruble by this method in the great majority of asbestos workers provided they have any exjiectoratioii. In the older workers, especially during a bronchitic attack and in the later stages of pulmonary asbestos)*. bodies are present in profusion, but. even in those who have only been engaged in the industry for a year or two. they- inay be demonstrable in small numbers. Their presence indicates merely that asbestos dust has lx:cii inhaled into the lung and that it has remained there long enough for "bodies" to form around individual fibers, a period of months at least. It docs not necessarily mean that there is pulmonary hbrosis. The finding of radially arranged dumps of bodies similar to those demonstrable histologically within the lung alveoli has iimcli more serious sigmhcaiicc. It indicates disinte gration of living tissue, oil her hv suppurative bronchopneumonia or In tuberculous caseation, and imiv lie taken also as presumptive evidence of an underlying h-Im'-Iom-. Bodies somewhat similar to asbestos bodies but much coarser and more irregular have Ixtii recovered from the lungs of coal miners who had never worked 111 a<iictu The morphological ililTercnees are so great, however, that there is lit.lc or no risk of confusion. / i / / e'/C t /hi METHODS FOR 1 Two steps are m First, reduce the di means of control de to dust "action amo means of suitable j medical examinntin problem of rnmrotin tion of medical or pi balanced program. Individuals vary of dust owing to difif weaknesses caused L tuberculosis, etc. selected for fitness chest X-ray picture inations thereafter resistance against d Two purposes an development of tubi the victim can be rci ous source of infect; prevent the develoi continued dust exp which lower the res in time to transfer t permanent damagt provides the only program, since in tl of lung damage ih: program. An made control ur the adopt 396413 1 STOOI 30 I 7