Document 3NJgYZLzK61Ye85NoMwEZdMDE

FILE NAME: Z//E DATE: DOC#: /E DOCUMENT DESCRIPTION::ZdZZZ ZZWZ&ZdZDD ' 11 1 ''a loboralory ---~ haler llence ~s the teroid on write to. ay 400 008 Tht! .~orr~lation of Chest Radiograph and Pulmonary Function Tests in Asbestos Miners and Millers i ~ S.K. Dave, L.J. 'Bhagia, P.K. Mazumdar, G.C. Patel, P.K. Kulkarni and S.K. Kashyap National Institute of Occupational Health, Me. 1iani Nagar, Ahmedabad An environmental-cum-medical survey was carried out in asbestos mines and milling units at Pullivendalla, Cuddaph (A.P.) India. This was done in two mmes and six milling unit.s..\yith..<?.S:JP Q.fJhe total work force being surveyed. Out of it total llt 633 regl'stered workers, 329 (5l%, "airmalesfwere em.plc)ycd in mines while L"i (21.4%) workers of whom I 14 (84%, all female~) were employed in the nil':ng unit!; All subjects \ln<i:;went limited medical examination, spirometry and chest radiographs. The levels ,Jl asbestos fiber concentration was much below threshold l11nit value (TLV) in underground mines but several ~imes higher than TLV in milli1:g unit>. The percentage of workers with abnormal pulmonary function tests (PFT) :nd chest radiographs increased with duration of exposure 'in smokers as well a~ no11.smokcrs. Restrictive pattern of lung functions ( 159 workers I6.27%) was more cwrnnon th:rn obstructive (33 workers-5.21 %) and combined type (22 workers-3.4%). S1 milarlj. the parenchymal changes (156 workers-24.6%) were more common than pleural (27 workers-4.3%). As most of the males were employed in mines, where the fiber levels were much below TL V, the number of male workers with normal PFT and chi~Sl radiograph~ were ten times (61.3%, more than male workers with both 1hc parameters abnormal (6.3%). As mo~t of the females ( 114 our of 120 95%) were employed in milling units, where the levels of fibers were ~everal time~. !n!'fwr th:q TLV, the number of females having b,>tJi the parameters normal 29 1 :,; l%) or abnormal 35 (29.2%) were similar. Key words : Asb<.1to.1 mines, asbestos n111ls, chest rarlio!it'<l[Jft, pul1"'m u v fwu 111;11 tests. [I11dian J Chest Dis Allied Sc, 19%; 311: 81-!NJ The rc-.,ulls of cxtcnsbc cpidcmir;logkul and toxicologicul studic~ h;:-.e conlirned that respiratory morbidity dtw 10 asbestos exposure is related to the do'c :111d dur:111011 (I exposure, the proces<>e': of work and type of fiber13. While studying respiratory morbidity due to asbestos exposure attempts were heing made to find out the relationship. of chest radiographs and pulmonary function tests Ill wnrk environment. Attempts were also made to observe the interdependency ot these two objective parameters with each other. While such efforts do not throw direct lig~t on, for Correspondence : Dr S.K. Dave, Deputy Director and Head, Occupational Medicine am! Epidemiology Division, National Institute of Occupational Health Ml"ghani Nagar.. Ahmedabad-380 016. S.K. Dave et"' 111-;tance, the prevalence uf health effects of hazards, they have lead to some interesting c.pcculation regarding the sensitivity of such tests in detecting the early charges in health -;tatus 4 \ In India, more than 30 mines are located in Andhra Pradesh and Rajasthan. The 'erpentine (Chry~otile-17 ,000 metric ton). varie~y is available in Andhr~ Pradesh and amphibole (Tremolite-25,000 metric ton) in Rajasthan. The latter variety is.technically of very poor grade. As per the directives of the Indian Council of Medical Research (ICMR), New Delhi, the National Institute of Occupational Health (NIOH), Ahmedabad initiated "Intervention study in asbestos mines and milling units in lqdia'' at the natwnal level. The tindihgs presented here are the part bf overall observations n:iade from the entire study whose objectives. were {i) to measure the asbestos fiber levels in mines and milling units, (ii) to assess the health status of workers in asbestos mining and milling units, (iii) to correlate the effec.ts of work environment on respiratory system in reference to two objective parameters, i.e. chest radiograph and pulmonary function tests and (iv) to find out the interdependency of two objective parameters, i.e. chest radiography and pulmonary function tests on each other. Material and Methods J:.:11vironmental Evaluation. The eavironment was evaluated in two mines and six milling units at Pullivendalla, Cuddaph in Andhra Pradesh, India. (a) Collection of samples. As recommended by the Bureau of Indian Standards (BIS)5, the millipore membrane filter method (MMFM) was used. The minimum number of samples taken wen~ four. A total of 157 samples were collected from the breathing zone of v.'orkers by personal samplers at various locations. The dust was collected on cellulose membrane tilter with 25 mm diameter and 0.8 m pore size at the flow rate of 1.5 L/min. (b) Counting. A phase contrast microscope (x 400) with Walton-Becklet graticule -,pecially designed for asbestos fiber counting was used. One hundred fibers or 100 fields were counted with 01i11i111um count of 20 fields: All tibers with length~ 5 m and diameter \width)~; 3 m and k11gth to diameter ratio 3 : 1 or more were counted. Fiber concentration was calculated by using Lhc following equation: (Ala) x (llr) x (lit) where A is for effective area, i.e. 325.88 mm2, a for graticule area, i.e. 0.006936 mm2, r for Jlow rate, i.e. 1.5/min, t for sample duration (min), N =total number of fibers counted, and n for number of graticule area counted (~ 100). Health Status Study. This study comprised of 633 (513 males and 120 females) workers (95% of the work force) of the asbestos mines and milling units at Pullivendalla, Cuddaph, A.P., (India). (a) Questio1111111rl' 1\ included a medical '>l'.ct11: bias non-smoker~ V. l'.1 c 1 Were Considered a\ \JIH>kt (b) Limited phys1rnl e presence of infra-axillar1 period of breath holdino: D (c) Spirometry. Spin performed a minimum oJ reading of the fon.:cd ex 1 (FVC) were u~cd for an Kamat et uP. (d)' Chest roe11tgcno g roentgenogram as per th, three chest physicians alll Results In mines, the levcb ol for chrysotile fiber ii e . Rule 123-J\ unde1 SLTli1 ,, applicable tb chry~ntilc n Tahll' I.' ------------ -- Scm1-McLhan1L Operation law crusher Loader Fiber 1nom I' Vibrator ['. I land scrc1:n 111g r'o Figures in parcnthc-.1' 111. ~- -~ -' to some interesting ly changes in health ind Rajasthan. The ndhr~ Pradesh and ety is.technically of I Research (ICMR), hmedabad initiated national level. The im the entire study 1d milling units, (ii) its, (iii) to correlate e to two objective Uv) to find out the Dulmonary function ies and six milling ' Standards (BIS)5, iirnum number of : breathing zone of ~cted on cellulose 1te of 1.5 Umin. Becklet graticule 1bers or I 00 fields m and diameter 'iber concentration l06936 mm7, r for 1 ber~ counted, and females) workers ~ndalla, Cuddaph, Correlation of chest radiographs and /'FT in asbestos workers X3 (a) Questionnaire. A standard questionnaire administered by traitH~d interviewers included a medical section, a section on occupational history and smoking habit". To avoid bias non-smokers were defined as those who had no exposure to tobacco and nmaining were considered as smokers. (b) Limited physical examination. Auscultation Was performed on site to determine the presence of infra-axillary crepitations heard at the full inspiration especially after a short period of breath holding at the low hmg volumes. . , (c) Spirometry. Spirom'etry was performed by Vitalogniph (7. I L). Each subject performed a minimum: of thr~e technically satisfactory forced expiratory manoeuvers. The re~ding of the forced expiratory volume in one second (FEV 1) and forced vital capacity (FVC) were used for analysis. Predicted normal values were obtained from the data of Kamat etaI'. (d) Chest roentge,nograms. All workers underwent a full size postero-anterior chest roentgenogram as per the recommendations made by ILO (1980). The films were read by three chest physicians and common agreement was taken for analysis89 Results . In mines, the levels of asbestos fibers were much below the threshold limit value (TLV.) fof~hn:~~itil~JiD'fr"ffe.-;:t:rflmffWKrCh~r;-acceptecr6y th;5~~~r~;;;~;;1 cif 1ndia in Mcidet Rule 123-A under Sectic>niTiof the Factories Act 1948 as ammended in 1987 which is also applicable to chrysotile mine and milling environmentw. Table 1. Mean asbestos fiber concentration i11 two types o( mi/11 Semi-Mechanic Operation (f/ml) Scmi-Autoni.1t1c ----------------- Operation ( f/rn I) Jaw crusher Deco1tic11tor Loader Fiber room Vibrator ~ Hand screening 244.14 (6.69-40.79) 52.27 (12.49-141.9) 45.92 (30,0-63.9) . 148.96 (91.05-220.79) 224.33 (96.77-488.05) 101.30 (51.54-214.71) Figures in parenthesis indicate range; TLV =:s; 2/ml Fiberision Primary screening Fiber collection Tailing plant (Feeding) T;iling plant (collection) 21 43 ('.U2-41.92) 33.27 (8.4-60.97) 75.28 (19.07-54.77) 144.42 l2 05-26.7<>) 3.98 (I .3h-6.60) S.K. Dave et al Jeverwas-fi(gh-estn;adhe The mean asbestos fiber concentration in two types of mills have been shown in table-I. Mean asbestos tiber concentration at various locations of the semi-mechanic mill was higher as compared to the Jc,cation of the semi-automatic mills. However in both the type of mills, the fiber levels wer,! >everal ti.mes highe~._tha 1 TLV (S 2 f/ml) at;iTJocatlons~Th~~!'fi~!!.~ !(tier au tom at ic- mi 11, the"hi.gnesfTe\ieT\vviabSr'aofbo~r-e(~2v2e4d~.2ne3arf/'mi~l~)J.ainH,1s~e~m-pil-amriet c(hFaeendi~z~eid:}W.~-il~l;. 4Ifn,.fs/memli),.- - - ' -- .,. - - - ,.. -- t -- ~- The distribution of workers according to the nature and ~ duration of exposure and ~moking habit in both the sexes is shown in table-2. The directly exposed group included workers working either in mining and/or milling, while those working as supervisor, mechanic, electricians, helpers, drivers etc have been included in indirect exposure group. Out of a total .of 633 workers, 341 (53.8%) had less than 10 years exposure, 186 (29.3%) with 11 tO" 15 years and 106 (16.7%) with.more than 15 years. Out of the total work force, 329 workers (52%, all males) w~re employed in mining, 199 (31.4%) in milling, 23 (3.6%) in mining ~nd milling and 82 (12.9%) in indirect exposure processes. Out of a tota,l of 513 male workers, 282 (54.9%) were smokers while 22 (18.3%). of the 120 females smoked. T11ble 2. Distrib11tio11 of workers a(:cording to nature and duration of expos;4re and smoking habits in both sexes Duration of CX[lO~lllC Sex (yrs) Direct exposure group Mining Milling NS s NS s ~ Indirect exposure group Mining+ Milling NS s NS s :::;: 10 M 341 (5:1.8'7<) F 11-15 M I 8(1 1,29.4%) F ;::: 16 M I 06 (16.51%) F 115 95 (22.41) (18.51) 34 ((lfl2) 40 (7.79)' 15 (2.IJ2) 30 (5.84) 20 (3.89) 26 (5.06) 32 (26.6) 8 (6.06) 7 (1.36) 17 (3.31) 41 8 (34.16) (6.66) 3 12 (0.58) . (2.33) 19 6 ( 15.83) (5,00) 4 (0.78) 3 (0.58) 2 (0.38) 5 (0.97) 6 ( 1.16) 3 (0.58) 17 (3.31) 2 (1.6) 7 (1.36) 3 (2.5) 4 (0.77) I (0 83) 17 (3.31) .20 (3.89) I I (2.14) Total 164 (2~.9) 165 (26.06) 122 77 (19.27) (12.16) 9 (1.42) 14 (2.21) 34 (5.37) NS:.:: Non ~mokcr. S =Smoker: Figures in parenthesis indi'cate percentages Male smokers= 282 (54.9~k). Female smokers= 24 (18.3%) 48 (7.58) Total , ~ '. 299 (47.l) 42 (6.6) 134 (21.2) > 52 (8.1) 80 (12.6) 26 (4.1) 633- ( or Tahle 3. P11/1 Operation group Direct expo.wre Mining Milling Mining and milling Indirect exros1tr<' Total Figures in parcnthc\1<. 1ml Impairment of lung tu1 of both the sexes is shov. common ( 103 workers-16. mixed pattern was observ I8.5%), the prevalence u wurkers-36.2%) and Ill wo workers of the indirect c impairment was near Iy counterparts. The radiological chall workers-54.8%) than miu changes in direct as well common (166 workcrs-26. was detected in 6 wo1 kc rs ln milling unit~ and 11 changes were more comm i' : . i:' , Corre/11tio11 of chest rtuilograplls cmd PFT in cuht's/IJs wprkers X'> 'e been shown in table- 1. ~echanic mill was higher in both the type of mills all locations. The rnea~ !Chanized mill. In semi(Feeding-144.42 f/ml). ation of exposure and !Xposed group included ,_,orking as supervisor 1direct exposure group: exposure, 186 (29.3%) of the total work force ,) in milling, 23 (3.6%) s. Out of a total of 513 0 females smoked. sure and smoking habits ~ group Total Milling NS s 17 17 .31) (3.31) 2 .6) 7 20 36) (3.89) 3 .5) 11 77) (2.14) n> 299 (47 .1) 42 (6.6) 134 {21.2) 52 (8.1) 80 (12.6) 26 (4.1) i 48 633 17) (7.58) Table 3. Pulmonary function impairment in different operation groups ~; Operation group .. , ..'i ' } ,, Sex Pulmonary function impairment No.of Restrictive Obstructive Combined workers Total '~ .'' ,, "' (, 1 t'{ ., ''. 1 ~; Direcr exposure Mining 'f 'Milling M 329 F M 85 F 114 Mining and milling M 23 lndi~ect exposure M 76 F 6 26 (7.9). 14 (16.5) 48 (42.1) 1 (4.3) 12 (15.8) 2 (33.3) 25 (7.6) 2 (2.3) 2 ( 1.8) I (4.3) 3 (3.9) 10 (3) 2 (2.3) 4 (3.'.'i) 6 (7.9) 61 (18.5) 18 (21.2) 54 (47.3) 2 (8.7) 21 (26.7) 2 (33.3) Total 633 103 33 22 158 (16.27) (5.2) (3.4) (25) Figures in parenthesis indicate percentages mi <n Impairment of lung functions in workers in both directly and indirectly exposed groups of both the sexes is shown in table 3. It '\\'_~~- ?_bserved that, ~~-~!~.iE!t''.,~..p,,att(!.r,~._ was mori.; ~~p9JIQ3,~Q~x~:.l.n.27%) as comp.ar~J<l,~h~ Q~s~!"ll~Jiy~ {3,~ wpr,k~rs-5._21%) whi,le a ml'S.~~~-2R3Jdl)'J;dJJJ.,22....w.o.r.kers (3.4%). As c~1!'P!-~~g,!!>.JJ1jners (61 workers- 18.5%). the p~~~~~'?.-?L~l1!!~ runc~~.2.?J~.e.~ir"~e~! wa~ ~~r~ 9~~!1'?n. in, 115 rs workers-36.2%) and m workers m the indirect exposure group (23 workers-28%). Inf~ Wc:Jrkers of the indirect ~x~~~':1.~.~J.r9yp__a,n~.,JltUliP.&,JlU~-~...lb.~.~v.~LW~f~,.9{res_tr!~JlY.~ impair~:W!g<JfE!!iJ'T~. '.t".Yo _to .lY,:'E:'.:l!l.~-ha,lf tim~!! more ~OQ:llJW!l .. ~h.a.n their mal~ coun~erparts .. T~e radipl~.S.J!.l~~L~~r.~. .m<?!~.son1JuopjQWO.rlq~r~ lo.the milling units ,(109 work~l.s'."54.S'!o) tn{lD.Jnini"i nits(64 workers-I 9.5%) (Table 4). All12!lgst r.adiq.W_gwal C~1f_ll8f; J~_direct-as well as indirect. exposure _gr<mp, parenchy!11al ~.fui,!1.~,~~':1-~~l!:.n:'.YJC c9Jninen{l66 WOf!kers--26:2%}thanplttitaf'one(27'wofk!f's:?4'.~'11,5:_.~p,.g~:;\I)'. ,t_upercu !_~sis was detected in 6 workef!H'ft>)-> ,l.l.QfJhem were ma\e. ~mR.~~ :.~ ~ : ~---'-:-r~';~',t,:.;;~t........"""'.r~-"- - -In milling units and in the indirect exposure group the prevalence of parenchymal changes were more common in females (mi1ling units-28 males. i.e. 33% out of 85 and 62 86 S.K. Dave et al '., ...! " \ ''.,; females, i.e. 54.38% out of 114; indirect exposure group 13 males. i.e. 17.1% out9f7'~d one female, i.e. 16.6% out o(6). Thus, the radiological changes also had a similar pattern a5 ~~: the pulmonary function tests. _ 't ' ' . . , ' ' " ' ~-.i-'' Correlation of chest radlographs and pulm<;mary function tests in aspes~o& ~ner~ and i'.;, millers of both the sexes is sqmmarized in table 5. O~t_ofthe total of SJ.3.Jmll~~~-lJ :' i~ <<it .3%) ~ere ha_ving ~th t~~ par~!ters no~~~hl\~-3tt~:~~Ili~~.!h.:!!lU!!!!~lt?J'$ :: abnormal. ('.jf the 120 iemale w9r:Kers~t~l%)liaa both the parameters nonnal whil~ 3~ (29.2%) had both param~tersabnormal. In case of male workers, 71 (13.8%) were witQ abnormal PFf and normal chest x-ray and 94 (18.4) had normal PFf and abnormaJ chest x.- ray .' In female workers the corresponding figures were 21. (17.5%) and 35 (29.2%), respectively. Here, it is wonhwhile to l)Ote that males were employed mainly in mines (underground) due to prohibition of _employment of females on such locations. Thus, .the females were largely employed in milling units (95% out of 120 females) and indirect Table 4. Radiological chang,es in different operation groups Operation group Sex No. of workers Radiological changes Parenchymal changes Pleural. changes Total Pulmonary tuberculosis IO RO co PT PC a /Ji rect r x1wsure Mining M 329 31 I (9.4) (0.3) F Millin M 85 28 (32.9) F 114 42 (36.8) Mining and !nilling M 23 3 (13.1) F Indirect exposure M 76 8 1 (10.5) (1.3) F 6 18 (5.5) 6 (1.8) 3 (0.9) 7 (8.2) 20 (17 .5) 2 (8.7) 4 (4.2) 4 (3.5) I (4.37) 3 (2.6) 4 6 (5.3) (7.9) 1 (16.6) 5 (I .5) 1 (1.2) 64 (19.4) 40 (47.1) 69 (60.5) . 6 (26.1) 19 ,(25) Total 633 112 2 52 (17.7) (0.3) ' (.S.2) 21 (3.3) 6 (1.0) 6 (1 ,0) 1.0. = hregular opacities, R.O. "' Regular opacities, C.O. =Combined opacities, P.T. =Pleural thicke.ning;P. Ca. :;::: Pleural calcification Figure' in parenthesis indicate percentages Cui Table 5. Correlation of rh millers Pubnonary function tests Normal Abnormal Figures in parenthe~1' i1a exposure process. As a re. females to much higher le in Model Rule 123-a und which is also applicablL conclusion, that when the the levels arc curnpa1at1vl' Dmcussion The fiber level~ were n Ole fiber in parent rock (: reduction of the fiber !eve Du Toit11 also observed th1 mining as compared to un< ln the milling uni ts, i locations the fiber levels \ Government of India in M ammended in 1987 and is be mainly due to three rca~, and safety act and (( J low and milling units, total pre milling units. Such a low ~ lr: the reason for their re>ist. r,evailing lack of awarent ~; 'absen~e of low cost indige1 ,. .:ontnbute to an extreme '1 :, Countries like Canada (Qu profitable asbestos mines w e. 17.1%outof76and 1.~ had a similar pattern as ~'. n asbestos miners and 513 maJe workers, 317 id both.the parameters eters normal while 35 71 (13.8%) were With and abnormal chest x;%) and 35 (29.2%), >yed mainly in mines i locations. Thus, the "emales) and indirect ups Pulmonary tuberculosis Total 5 ( 1.5) 64 (19.4) 40 (l.2) (47.J) t" 69 (60.5) 6 (26. l) 19 ,(25) 6 (1 O; c1t1cs. PT. = Pleural Correlation of chest radiogmphs and ~'FT in asbestos workers 87 Table 5. Correlation of chest radiographs and pulmonary function tests in asbe.llos miners and millers' Chest radiographs Normal Males (513) Normal Abnormal 3n (61.7) 94 (18.4) Females ( 120) Normal Abnormal 29 (24.1) 35 (29.2) Ahnqpnal 71 31 ( 13.8) (6.3) Figures in parenthesis indicate percentages 21 (17.5) 35 (29.2) exposure process. As a result males were exposed to very low levels (i.e.,~ 0.5 tJml) while females to much higher levels than the~V (~ 2 f/ml) accepted by the Government of India in Model Rule 123-a under Section 112 of the Factories Act 1948 as amm.ended in 1987, whiCh is also applicable to chrysotile mi.ne and milling environment. However, the ~onc,lsion,,~at when the fiber levels are too high, chest radiographs are affected and when the levels are' comparatively low, pulmonary function tests are affected can't be derived. min1rig"aoes'piay'"ii I r.{' " Dl11cwislon ,' ,, . ~1.~ ~ i:F-:~0~~~~~f!.\~,-~ :, ~E, , T,lle :fiber levels were much below TLV ..ifl ~i!les ~ue~to wet drilling and low content of ' Ulelf~~1'Jt'~fl'bClC(~"~%):uncierground signiflci1i1t role in the red~iibh~_otthcrfiber levels to a significant extent. In the South African mines, Gibbs and t:: OtiToit'J'also.observed the levels of asbestos fiber were two to thrt;!e,times higher in surface mmmg '. ~- ..,. as c'o- mpal re cl to underground one. In the milling units, in the general work environment, as well as at variou~ other locations the fiber levels were much higher than TLV (::; 2 f/ml) which i~ accepted by the Government of India in Model Rule 123-/, Jnder Section 112 of the Factor1e' Act 1948 a'> ammended in 1987 and is applicable to chrysotile mine and milling environment This can be mainly due to three reasons: (a) obsolete technology, (b) inadequate compliance to mine~ and safety act and (c) low content of asbestos fiber in parent rock: In Pullivendalla'mine'> and milling units, total production of chrysotile is approximately 17,000 metric ton by six milling units. Such a low yield gives poor economic re'turns to mine/miU owners which is the reas\'n for their resistance in. investing in environmental engineering controls. The prevailing lack of awareness about health risks due to asbestos in miner ancl millers and to absenceof low cost indigenous technology aggravate the problem further. All these factors I. contribute an extremely dusty working condition in the~e asbestos milling units. i,. Countries like Canada (Quebec) 1 ~. Cyprus 13, ItaJyH and South Afrtca11 have economically profitable asbestos mines which contribute nearly 30% of the total world production. Studie~ ,_ t ' ~ l ' 88 S.K. Dave et al carried out in these count~~es reported significantly high levels in ..;eneral mill '" envirQnmem. : . 4o However, records maint~ined since 1940 in South Africa, Canada and Italy docum~nted significant decrease in the environmental concentiation of asbestos fibers over the past years11.12.14. , '. 'c We observed that the gerce.ut~,g~of male workers with both parameters normal (61.3%) was t~lr'e tlJ.&.!lS.M .R~r"'enta.ge qf)YP'Qcersw1'ifi'oofft~ ffie..parairiei~rs "abnQrQJal (6:''.i"(f,;)'.'tlOW'CVe7,i; cases ~of female ~~~ke~&-''ihe're'wis-not much d'iffereii~e in the ;r. percentage of workers having both the parameters normal (24%) and abnormal (29%). Thw could be due the 1act that in underground inines only males are permitted legally to work and the fiber levels were much below TLV in these mines. This results in females being " predoii1inantly employed in milling units and other indirect processes where the fil?er levels were several times higher than TLV. Thus, the highly significant difference in fiber levels between mining and milling units kept male work force healthier than their female counterpart. Similarly restrictive pattern of PFT and r~diological parenchymal changes mainly in the form of irregular linear opacities were more common in milling workers than in miners. ' .' A study carried out in ~(itish Coluipbiar,eported decr~ed levels offorceq,vi~icapity. ;; in those working in the milJ area knowh for its high'ievels of exposure to ati~~tQi. ::Y~r~~~ ~, Similar magnitude of defic\t of FVC.(8.9%) has also beenreported in a Quebev:&tuP,y,1.6..W~ 1i\ l\n41\i; noted parenchymal changes on radiology in 12.2% of the workers stuqiect. whicib was ,\g . '.: conformity with similar stl,ldi~ i1;1 J~s~sto~ mines aQd milling units in Queb~'~.<:;Yp.r1H1>1f ~, Italy 1 ~ and British.Colum~i~is .where p~renchymal changes observed were .8%, S%";. 29% 11 %, respectively. The figures for pleural change~ v~ried from 2 tQ 7% in ~11 these1~tudic* :::, except in an Italian study where it.wa,s. 13% 13 Studies ofJung function and.radiography have lieen reported from Quebec4 and Italy 13 and in both the studies !eve.Is of lung function was noted to be related to the abnormalities observed radiologically. The analysis of these studies also revealed that inter-relationship of the two objective parameter~. i.e. ches~ radiograph, .spirometry and their dependence on environmental levels of asbestos fiber. It also depends to a major extent on pre-employment health status and individual host susceptibility41116 . References ... I. lrw1ng RS, DuToit J, Sluis-Cremer GK, Solomon A, Thomas R. Risk of asbestosis in crocidolit . :, c and amosite in South Africa. Ann NY Acad Sci 1979; 330: 35-52. 2. Rossister CE, Bristol LJ, Cartier PH, 1'1 ctl. Radiographic changes in chrysotite asbestos mine and mill workers of Quebec. Arch Environ Health 1972; 24 : 388-400. 3. Felton, Jean Spencer. Radiographic search for asbestos related disease in a naval shipyard. Ann NY Arnd Sci 1979; 330 : 341-352. 4. Becklakc MR. Fournier-Massey G, McDonald JC, Siemiatycki J, R-0ssister CE. Lung function in relation to radiographic changes in Qi'iebec asbestos workers. Proceedings of the lnternatwrwl Con/en nee on Pneunwconiosis. Johannesburg, SA. 1970: 233-239. 5. Bureau of Indian fiber concentratior 6. American Lung A adults and chilclrc1 7. Kamat SR, Tyagi I : 11-21. 8. hiternational Lab Pneumoconiosis (I fice, Geneva, Swit 9. Rossistcr CE. Har Proceedings of the 10. Exposure limit~ in Labour Office'. 198 11. Gibbs GW, DuToi Scientific Publicati .12. McDonald JC, Be chrysotile asbestos 13. McDonald JC. Asb Scientific Pub/1cati, 14. Vigalani EC. Asbc Conference on Pnr" 15. Enarson DA, Emh1 miners in British c, 16. Becklake MR, Fou. asbestos mine and r !! . 1:t~. ,.. l>:' . ,1 ~I J~ ti general mill environmend~ 1da and Italy documented ;~~ os fibers over the past 40 ;~ l trameters normal (61.3%) he parameters abnormal much difference in the" nd abnormal (29%). This iermitted legally to work results in females being. l ses where the fiber levels ~ difference in fiber levels . :thier than their female 11 parenchymal changes J in milling workers than s of forced vital cap!lCity ~ure to asbestos fibers5, 111 a Quebec study'a. We s studied which was in in Quebec416 Cyprusl, were 8%, 5%, 29% and >7% in all these studies nction and radiography ; levels of lung function Y The analysis of these ' parameters, i.e. chest els of asbestos fiber. It JS and individual host Correlation of chest radiographs and PFT in asbestos workers 89 Bureau of Indian Standards IS 11450-1986. Method of determination of airborne asbestos fiber concentration in "'.'ork environment by Jigh~ microscopy. American Lung Association. Recommended respiratory disease questionnaire for use with adult:S ~d children in epidemiologicali reasearch. . Kamat SR, Tyagi NK, Rashid SSA. Lung function in Indian adult subjects. Lung India 1982: I: 1121. 8. 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JARC-Lyon, France; 1973: 189-194. 14. .. Vigalani EC. Asbestos exposure and its results in Italy. Proceedings of the 2nd International Confei-ence ori Pneumoconosis, Johannesburg, SA, 1970; 192-196. . 15. , :: ~ Enarson ~ DA, Embree V, Maclean L, ' . Grzybowski ' ' t.,. Respiratory health in chrysotile asbestos miners in British Columbia : A longitudinal study. Br J Mtfd 1988~ 4S : 459-463. CE, 12. 16. Becklake MR, Fournier-Massey G, Rossis~er McD~n~ld Lung function in chrysotilc asbestos mine and mill workers of Quebec. Arch Environ Health 1972; 24 : 40,1-408. ot L'>hcstos1s in crocidolit < l1i:''-tJlde a~hc.:stm mine l ;a~c m a naval shipyard. ;-;ister CE. Lung function iceedlligs of the lnterna239.