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ANALYTICAL CHEMISTRY
for another rafter sample R-3 (see Figure 1 for the foundry layout). The collected Visi-Float samples vary from 13.19% for Z-1 to 2.20% for 2-8. A notable exception to the inverse relationship is sample 2-5 from the core sand mill with 4.34% iron and 6.3% quartz. For set I of the dust samples whose quartz contents are tabulated in Table 11, chemical analyses were attempted. There were differences in color of the samples: the predominant color was black, with several appearing brown. Spot tests were performed on all 20 samples and those that appeared gray (as
received from the foundry) showed no presence of iron; some of black indicated iron and others did not. Table I X indicates the amount of iron found in each sample. Since the spot tests indicated the presence of both ferrous and ferric iron, it was necessary to reduce the iron completely to the ferrous state and then determine the per cent iron by cerate oxidimetry using o-phenanthroline as an indicator. The chemical analyses give considerably lower results than the carefully calibrated fluorescent-spectral analyses, even though two sets of dust samples are involved.
(X-RAY ANALYSIS OF FOUNDRY DUSTS)
Interpretation of Results and Correlated Medical Observations G. L. CLARK,
Department o f Chemistry and Chemical Engineering, University o f Illinois, Urbana,
L. E. HOLLY, Muskegon,
111.
Mich.
T
HIS is the first time a university laboratory has cooperated closely in the quantitative correlation of the health hazard problems of a large representative steel foundry. I t has been possible to study the hazard itself in regard to each of the functions carried out in designated areas of the foundry, correlrting this information with the data on dust concentration and constitution and with medical applications. The medical application has been made possible by making use of information obtainable from periodic chest x-rays of the foundry personnel under the direction of an eminent radiologist. As workers have been employed in their present operations at the foundry for an average of 20 years, this enables information to be applied to recommendations for future hazard control. Excessive inhalation of silica dust generally produces a seriouy pulmonary disease. For some reason, yet unexplained, silicon dioxide as quartz may produce a diarhling form of lung fibrosis. The American definition (2j of silicosis states: I t is a disease due to breathing air containing silica (SiO?) characterized anatomically by generalized fibrotic changes and the development of miliary nodulation in both lungs, and clinically by shortness of breath, decreased chest expansion, lessened capacity for work, absence of fever. . .
The Journal of the American .lIedical .4ssociation ( h i states that: Only silica (Sios) is capable of inducing silicosis but any other mineral dust under conditions of prolonged exposure and gross exposure may cause some increase in pulmonary fibrosis. If the relative potential harm of silica is rated as 100, these other nontoxic mineral dusts may be rated only on the order of 5 and 10. Moreover, the fibrosis is in itself not pathognomonic, since many other dusts, alkalies, acids, or vapors may induce somewhat eimilar if not identical x-ray markings. I n general, the damage done in silicosis is permanent; an unalterable tissue change takes place in the lungs. Deaths from uncomplicated lung fibrosis caused by dust are infrequent (d), but susceptibility to tuberculoais, pneumonia, and other respiratory diseases is known to be greatly increased. The mechanism of the action of silicon dioxide in producing silicosis is the formation of silicic acid when silicon dioxide comes in contact with body fluids. The silicic acid so produced seems to be the causative agent in nodule formation. Another theory is based on the piezoelectric properties of crystalline quartz as compared with silicates which are essentially amorphous and do not possess similar electrical characteristics. The length of exposure that will produce silicosis varies with the working conditions and individual susceptibility (6). Thus rapid and accurate methods of dust analysis are needed to study working conditions.
The practice at the foundry is to employ aluminum powder inhalation for preventing silicosis. This is on a voluntary basis and is not a substitute for good housekeeping. The mechanism is thought to be the formation of aluminum hydroxide which neutralizes the silicic acid and thus prevents the formation of the silicotic nodule. Sone of the oxides of iron, or fine iron dust, in themselves, have been shown to be dangerous upon inhalation into the lungs, although the lungs of men who have been exposed to the iron dusts are colored characteristically and are called siderotic, and an x-ray chest film may show changes confused with silicosip. Perhaps t'he most significant observation of this investigation is that in areas where there is little or no concentration of quartz, x-ray photographs of the chests of workers show progressive changes. This can be explained in part by the fact that in areas of l o a or no concentration of quartz, there is usually a fair concentration of iron, which can be present as finely divided metallic iron, oxides, carbonates, and possible silicates of iron. Ihidences of crystalline iron and its compounds are rarely found in the diffraction patterns of dusts, indicating very low concentrations or essentially amorphous or colloidally dispersed phases. Iron, being of relatively high atomic weight, will produce shadows in small concentrations (siderosis). Iron probably undergoes hydration on the moist lung tissue to form a gelatinous colloid and this in turn very slowly forms innocuous iron silicates. There is no evidence that iron is antidotal to silicosis when injected in vivo, although aluminum dust does have this action. Unfortunately, data on siderosis are extremely fragmentary. Inspection of Figure 1shows that the working or actual foundry areas in which pollution of air by dusts is a problem of industrial hazard have been grouped into a number of larger zones labeled 4 through H , inclusive. Zone A includes the areas from which samples 2-2, 2-3, 2-4, and R-1 were collected. 2-2 is an area in which three sand mills are located; 2-3 is the small ladle repair area; and sample 2-4 was collected a t the breathing level near the crane over the double shakeout, Sample R-1 was taken from the rafter in the main bay over the double shakeout, in the same area as 2-4. The types of jobs in Zone A include bench molding, squeeze molding, pin lift molding, a small bumper, small floor molder shakeout, skimmers, pourers, crane operators, small ladle liner, sandmill operator, carryout, and supervisors. From Tables I1 and I11 it is found that a significant amount of or-quartz was found in the dust from areas 2-2, 2-3, and 2-4. 2-4 is considered the most hazardous zone, and this sample was collected from the breathing level. A significant amount (25.5 and 33.8%) of quartz was found in the rafter sample taken from area 2-4. In Zone A , there has been a record of 14 cases of distinct silicotic nodulation in the lungs to date.
V O L U M E 26, NO. 9, S E P T E M B E R 1 9 5 4
1419 the main bay, over the large shakeout near area Z-10. The quartz concentrations determined upon analyeing the dust samples obtained from the areas in this zone vary from very low to moderately high. The sample R-2 shows a comparable percentage of quartz. The workers employed in this zone include floor molders, a shakeout, molder helper, and snpervisors. In this zone (comprising all three areas), 24 workm have heen under medioal observation. Zone H includes areas 2-12, 25-13, 2-14, 215, and Z-16. Sample R-4 was also collected in this zone, near areas 2 1 4 and Z 1 5 . Samples 2-12 and 2-13 are low in quartz and moderately low in concentration. 2 1 4 , Z 1 5 , and 2 1 6 8hOW at present no quart5 in the dust collected. A new dust collector has recently been installed in the foundry, which services these arms. The set I dust collcoted from the rafter marked R 4 showed DO eoncentration of quartz but the set I1 sample contained 16.2% quartz, indicating less efficient ventilation after one year. 2 1 2 is the outting area (the sample was collected near the number three wheelahrator); 2-13 is the welding area; 2-14 is the grinding area; Z-15 is the small-parts finishing area; and 2 1 6 is the large-parts finishing area. The rafter from which R 4 sample was taken is over the annealing area. This zone comprises a large part of the foundry, and various types of workers are employed here, including cutters, grinders, chippers, blast machine personnel, crane operators, supervisors, material handlers, straighteners, press operators, annealers, chainers, inspectors, shipping laborers, and welders. Typical lung changes were noted among these workers.
men, chargers, a large ladle liner, crane operators, and a supervisor are engaged in foundry operations in this zone, where there have been four cases of lung disease of varying degrees. Zone C includes only area Z-5, the mill platform area in which the sand reclaimer is located. This area, from whioh sample 2-5 was colleoted and analyzed, shows a concentration of about the mme as in zone B (see Tables I1 and 111). Here %refound the sand reclaiming operator, core sandmill operator, and supervisor; two workers have developed nodulation as evidenced in radio" . . . graphs Of their lungs, Zone D includes Dniy area Z 6 . The percentage of quartz 7 c L ..+ 1Yrl.1.- l.yuyL.u ^F - ^..^" higher than in & r e &7~- 7 ""A "-", uuy v1 u-'lun. collected per hour is much less, making this a somewhat le oritical area hut nevertheless a haaard. In this me&are four coremakers (2-6 mea is the large core room), oventenders, psster core wheelers, and supervisors. Nine workers are under observ; tion. Zone E, including only 2-7, is the small core room which w: no longer in use when set I1 samples were collected. This a n analyzed very low in quartz as compared to the others, an except for 2 1 2 and areas which show no quartz content is t k lowest in concentration. The same types of workers are found i eone E as in zone D. Six workers have been under observation. Zone F includes only area 2-8, which is the slinger area. 11 . .- . . . . .. . .. . . . . . . . .. . . speetion of 'I'itbles I1 and 111 show8 that this IS tarly high in per cent quartz concentration in the dust collected. The workers include slinger molders, crane operators, sandmill operators, Bhakeout, m d supervisors. Sample R 3 , collected from the rafter over the slinger area, was likewise found to he high in silica content. Zone G includes 2-9, 71-10, 2-11, and the rafter designated R-2. 2 9 is a molding area, Z-10 is the large floor shakeout area, and Zll is the large floor shakeout crane. The sample from the latter area was collected st operator level. The rafter R-2 is in
.
...,+
Figure 5 . Chest Radiograph of Foundry Worker Showing Silicotic Nodules To illustrate lung changes of foundrymen upon e x p o m to dusts, radiographs from a file of several hundred are shovn in Figures 4, 5, and 6. For each man three or four chest radiographs were made in 1937, 1947, 1951, and 1953, so that initial development of siderotic or silicotio conditions could be detected and any progressive changes followed evcn with the use
1420
ANALYTICAL CHEMISTRY
of aluminum dust therapy. I n general, each man performed the same duties in the same area8 of the foundry over the 16year interval following original radiographic diagnosis. Figure 4 represents a typical normal chest; the lungs are free from fibrosis or nodulation. The individual was a truck driver for the foundry, supposedly not exposed to dusts, but subsequently his lungs did show some progression toward silicotic nodulation, so that exposure in the plant was greater than could have been predicted for this type of work.
than in the case exposed to silica only, by virtue of the difference in atomic number and resultant differencesin x-ray opacity h e tween iron, No. 26, and silicon, No. 14. Though siderosis is generally considered to he benign by medical experts, radiographs m y give an appearance very similar to that of silicosia. It is essential, therefore, that the case history be well known and a series of filmsover time intervals be made. SUMMARY
An intensive study has been made in all sections of B large midwestern steel foundry of the concentrations snd compositions of dusts which may constitute a hazard upon inhalation to the workers, especially in development of silicosis. Since wquarta is the established cause of this disease, quantitative anEIySiS of dusts must he made by x-ray diffraction techniques. The Ceigercounter diffractometer is employed for rapid, accurate, and reproducible results on the percentage of crystalline quartz, with calcium fluoride aa an internal standard. The staudard working curve deduced from experimental data linearly relates diffraction intensities with composition. Two sets of dust samples collected from the 8ame areas, one a year after the other, were analyzed on two different Geiger diffraotometers by two ohaervers. Iron is also determined chemically and by tluorescentapectral analpis in all the dust samples in order to ascertain any lung effects defined as siderosis. The second technique is remarkably successful in terms of accuracy and convenience since the same x-ray unit is used 8.8 for the diffraction analyses of quartz. Dusts vary in quartz content from 0 to more than SO%, and in general the amount of iron varies inversely. Since many workers in the foundry had been employed for more than 16 years in the same duties and the same areas and since lung radiographs periodically made over a period of 16 years were available for each man, i t is oossible to study the development and progression of evidences of &otic nodulation (a pathological condition) and of siderotic changes, supposedly benign, which are often difficult to d i s tinguish from silicosis, as related to the hazard of the particular ,occupation. The effects of ventilation and of aluminum dust .therapy are thus ascertained. LITERATURE CITED
Figure 6. Chest Radiograph of Foundry Worker Showine Evidence of Iron Deposits Diaenosed as Siderosis
Figure 3 mows DY contrast well-developea noauiauon cnaracteristic of silicosis for a core psster with silica. exposure only after 17 years in this occupation. I n 1937, this worker exhibited a normal chest after being a core paster for 7 years, but in 1947, after being a core paster for 10 years longer, a cheat radiograph showed earlv shdows in the luna.~ apex. After 6 ” condomerate more years, the film shows maturation of the silicotic nodules. For workers exposed directly only to iron-containing dusts, the ohest radiographs illustrate the condition defined 8s siderosis. Figure 6 is a typical example of tb siderotic lung in the ease of a worker who bad been engaged in welding for 5 years and chipping of castings for ll/n years. The film shows reticulation and beading, hut in 1953 progression had occurred 60 that nodulation attributable only to iron exposure is exhibited. Thus evidences of siderosis on the films actually may auuear considerablv sooner
G
,(I) Clark, G. L., and Reynolds, D. H.. IND.ENC.CESM.,ANAL.En.. 8, 36 (1936). m(2) Drinker and Hatch, “Industrial Dust.” 1st ed.. .. UD. 2LL63. New York. MoGraw-Hill Book Ca.. I 936. ,(3) Goldman, F. H., Public Health Repts., 5i2, 1702 (1937). ,(4) J . Am. Med. Assoc., 103,1472 (1934). 1. Hyg, Tozicol., 30, 160 ,(5) mug, Alexander, and Kummer, J. In< (1948). (6) Sohmeleer, L. L.. Arch. Id. Hug. and OccuwiiOd Med., 3,121-8 (1951). RECEWED for review June 25. 1953. Accepted June 10, 1954. Presented ’before the Diviaion of Analvtical Chemiatry at the 123rd Meeting of the AXIERICAN CBEMI-~OCIET~, Los Angelea, Calif. Based upon B thesis s u b mitted by Firat Lieutenant William F. Loranger. USAF. and portions 01 thesea submitted by 8. I. Bodnar and H. C Perford. in partial fulfillment of the requirements for the degree of doator of philomphy at the University of Illinois. Urbana. Ill. ~
X-Ray Diffraction-Correction The authors of the article on “X-Ray DiEraction” [ANAL. CHEM., 26, 31 (1954)l should have been given aa H. S. Kaufman and Isidor Fmkuchen.
