Document rO8MMew9O5qZagk0vRVy73De

Occupational exposure to benzene in China S-N Y I N . Q L1. Y L I U , F T I A N . C DU, C JIN From ifw ltisfirute of ffeulfh,Chlncse Acuhrny of Medical Sciencr.v,Eeijing, Peoples Republic of China ABSTRA~'T Of 3 total of 528 729 workers exposed to benzene or benzene mixtures in China, 508 E (96.73%)were examined. Altogether 2676 cases of benzene poisoning were found, a prcvalence 0.514;~ A higher prevalence of benzene poisoning was found in the cities of Hangjou, He! Nanjing, Shcnyanp. and Xian. The geometric maan concentration of benzene in 50255 workpla, was 18.1 mg:'m3 but 64.6% of the workplacas had less than 40 mgjm'. There was a posit corrcI:rticrn betwccn the prevalence of benzene poisoning and the concentration in shoemak factorics. The prcvalence of benzene induced aplastic anaemia in shoemakers was about 5-8 tjn that w x r r i n g in the general population. The resuits of this invlstigaticln show thc need fo practic:lble hygiene standard to prevent benzene poisoning. In C h w loday benzene is used more and more widcly as induz;tn develcips. I n the 19SOs it was used in painting. shotmaking. and in lhe production o f benzcnc hexachloride. A1 that time 3917 benzene workers in factoriw w e n examinad and 48 1 cases ofchronic benzcnc poisoning were found, a prevalence ratc of 10.19r (reponed at 1st Nutiotrnl Conference of Oecup;irional Health and Diseasc in China. 1960). In the 1WJs 33312 benzenc workers were examined in cities o r a m s of 11provinces and 366 cases of chronic tenzcnc poisoning wcrc found. a prevalence rate of l . l o k . To obtain scientific evidcnce for recommrn- dine prokcLive inmsures against benzenc int~xication an &exipntion of the whole country was undertaken from 1979 IO 198 1 , tective measures were survryrd and tht atmbsph benienc concentration determined by gas chrom. graphic or colonmetric methods. PEKSCJNA L E X A M IN A T IO N Enquiries about occupational histov, pcrsr health. physical examination, and blood counls i mode on cvcry worker and diagnosed accordin the Cntena of Chronic Bcnzene Poisoning issue 1974 by the M i m t r y of Health in China. These ar histoy of benzene cxposurc, ( 2 ) leucopacnia (V <4000/rnrn3), and (3) other bkod disor excluded. Results $ub*a Between )979 and 1981 workers in 28 provii except Tibet and Taiwan. were investigatcd. The d$x.ls for invcstigalivn included workers e x p o d 10 knzcnc or benzene mixturcs working in all ~ X I L ~ i~n Sthe wholc country They worked in the painting. p;iint production. shoe manulkturing. organir sqnrhcsis. insulation varnish. and printing induclrib%.and rubber and petrolcum refineries. 31elhb l S D l STRIAL HYGIENE SURVEY In hctory the proccsses of production and pro- G E N E R A L STATUS Of the 528 729 workers exposcd to benzene or zcnr mixtures in the country, SO8 818 (96.23%) txamincd Of thesc. 26 314 (4.98%)were expos benzene and 501411) (4542%) to mixrures collta benzcnc. The benzene mixtures usually conti benzene. tolusne, and xylene in varying GO] trations. The SOUrCG or the benzene (and mix1 was mainly petroleum refineries. There were 27 808 factories using benzcnp a$ vent or 3s a chemical intetmediatc in the whole try. of which data were obtained From 19965 Lories. Within these premiscs the kl conccntrdtion of 50155 workplaces was detm 92 #ccuparionnl exposure 10 benzene in China I93 and in 32486 w~rkplaccs(64.6%)it was less than 44 rng/rn5. Thc geometric mean conccntration of k n zene was 1S.I mg/rn3 and the 95% range was ~~06844~m7g/4m3: 1.3% of workplaces had benzene concentraiions in cxccss of 1000 mg;rn' (fig 1). PREVALENCE RA'IT AND DISTRIBUTION OF BENZENE POISONING Among the bcnacne wur-kats rxarnined,2676 cases of benzcnc poisoning were found. ;L prevalence r a ~ cof 0.51%.The prcvalcnce rate of'benzene poisoning was 0.94% in the workers exposed to benzene and 0-440/b in the workers exposed to benzene mixturcs: this difiercnce is statistically significant (p 0.05).The prevalence mle or benzene poisoning was hiphcr in _y __._____ Shmm*king Paint producmy Puinriag Spray pdmting & n m c refining Chemical rynrhcslb Phsmmxrblti Rubber Insulation varnirh Printing Lodint warkw Orhen Total 19213 I2359 101 379 175513 6 452 42 1M h 576 13x17 14 37n IS 453 870 35906 434 542 240 67 415 682 I1 I90 41 56 I01 46 7 142 I998 125 0.54 0.4 L 0.39 0.17 0-44 0.62 0-40 0.4 I 0.30 Q40 04.l R I S K UF R E N Z C N E IN D I F F E R E N T f Y P 6 S OF IN b USTIt IES There were about 280000 paint workers and this was the largest group of workers examincd. The percentagcs of workrrs in pinting. organic synthesis. insulation varnish. and shuemaking industries were 6 3 6 10-9.54, arid 4.2 respectively. The printing, rubber. and rcfinery industries were all less than 3.5%. The prevalencc ratc of benzene poisoning wa6 1.25% in the shocmnking industry and 0.54% in the painting industry {tablc). R E L A T I O N B E T W E E N THE I N C l O E N C I OF L ~ U C O P A E N I AAND T H E B E N Z E N E C O N C E N T R A T I O N IN D I F F E R S H T 1 N P U S T R l E S Bascd on the data from 24985 factories. the relation bctwecn the incidence ot' Icucopaenia (WBC < 40000/mmJ) and the percentage of factories with low bcnrenc concentration ( e 40 mg/m') wa5 estimoted. The correlativn coefficienr was -0.5 (p < 0.05). That is 16say, leucopacnia is more likely to occur in indus[ties i n which the benzene concentration is high. C C J N C E ~ ~ T ~ A T IROENS P O N S E R 6 L A T l c S N OP BENZENE Among the 141 sbocrnaking factories were 28 in which benzenc poisoning was found.Among the 7740 workers employed were 124 cascs of benzene poisoning. A positive relation between the prevalence 6t' poisoning and airborne benzene concentration was found (fig 3) and the cornlarion cocfficicnr was 0.42 ( p ~ O ~ O S )T.he benzene concentration was higher than 25 mgjm' in 86% of the facrorics and about 10 rng/mJir, only a [CW factories. Thesc msults show that cases of knzcne poisoning may occut Even in hctones with low conccnrration ( ~ 4m0g/m% I t there- fore seems desirable co consider the revision of prescnt hypienc standard for benzene. APLASTIC ANAEMIA A N D LEUKAEMIA Twenty four case5 of aplastic anacmia and nine of leuksemia werc found in this invcstlgarion. Of the 3 cases of aplastic anaemia. complete rccatds vlm available in 17; sevcn inen and 10 women agcd from 18 to 61. They were exposed to knzcne from 3.5 months to 19 year;. Most c u e s mrnc from shop making and paint production factories but a few & came from glueing and rcpairing and some from packing insecticides. The bcnzene concentration! were generally above the hygiene standard 93-1 156rny,~m'. For cxample. in a shoemaking factory sandals wen produced Trom July 1980 to March 1981. A mixtun of chlorabutadient and benzene ( I :3) was used IL adhesive. Four cases o f aplastic anaemia wcr detected among the 21 1 manual worken employedi this workshop during thc eight month period. A showed typical signs. svmptoms, and changes in tb bl4od afld bone marrow. The workers with WPlaSt anaemia had been csposed to benzene for an averal latent period of 118.5 days and their daily rne8nCO" ccnrtation was estimated to be about 1035.6 m g h The total amaunt of inhalcd benzene wP6 ab0 8278 g. The incidence of aplastic anaemia in this f! lory wn5 1.9?/0 and it was ordered LO stop productu after the cases occurred, Thcy then used a b solvcnr containing no knzcne and no further cs devtlopcd. 9 Nine cases of benzene leukaemia were found in t investigation. six men and three worntn a g d from to 62. Thcy werc exposed IO benzene from scvcn years, except for onc worker who was exposed &mparrpnal c.rposurc to benzene in Chrna oat! two years. There were four painters. one shoed e r . one insecticide packing worker, one cleaner. two analytical trchnicians. Or thc cascs, six wcrc diagnosed as acute myelocytic leukaemia. whereas the a r b s wcrc diagnnscd as acutc crythroleukscmia mc monocytic leukaemia, and acute lymphocytic leulamia. respectively SIX had had a prcccding kukopaenic or pancytopacnic period IkussIon This is the first report describing in deuil an m\&gation of the occupational beiirerlr hazard in h e whole of China. The results or the lnvostigalion underline the risk of benzene and present the dimibu- tion or brnzrnr poisoning in diffcrent industncs and he relation between benzene poisoning and the air- h e comefirration. It provids an imprlsnl aiFntificbasis for cvaluatinp the risk from benzene in Cba. DISTRIBUTIOK OF B E K Z E N E P n l S O h ' I N G More than 500 000 workcrs wcrc cxposed to bcnzenc or h e n e mixtures. the largest numbcr cxposcd to indmrial chemicals A total of 27803 factories or , workshops used benztnc and thc prcvalenct of ben- a poisoning mas 0.59.b This ts much lower than rtported in the LYSUs IO^ I% 1, and shows that the b'f&ne conditions of wor.kplaws w5u in gcnrrd bmcr than at that timc. Ncvcrtheless. the situation ' F i n p ~ I I Z C R Cpoisoning was worse in a rcw fat-loncs atld cities, calling Tor spccial attention in these plar?a. 1 h e m w x usu:~ll) uscd 35 a snlvmt and as a mning mairnal in organic synthesis. Mosr of the b e workerr (about 90%) uscd bcrvlcnc as a sol"W. fhe rcsulrs showed that the prevalence rate of b c pokuning was slgnificantlv lower in workers Sposcd to bemenc mixturcs (containinp, toluene, 'ha,nd henzenej than in lxnzenc workcrs. Thc rse of toluene and xylcnc instead of benzene is an 8w.ive mtgsurc for preventing h n z c n c poisonjng. b a t a lecture in China in 1979, also reported this ; lapC an impomnt measure for tontrolling bcnzenc hning. population in Mudanjiang (thr norlh rail uf Chinu) The prevalence anlong shoemakers was 5.8 limes that of ths general pnpulaiinn, The investigatlon <hawed rhar aplastic anaemia could develop in B ~ O U LI 18 days in workcrs cxpoycd to benzcne concenttntions 31 n level of 1035.6 mg/m3. Further study is ncccssary in ordcr t e have a btrret understanding of rhe course of benzene induced aplastic anamia. Wc than), Rofcssor LI Yurui and Dr Robert Murray. prcsident of the lntcmat~ona! Cornmisrior~ on Occupational Hnllh. fnr a critical review of this rniinucnpt This in\cs~igdlionw s supported hy rhr Minirtr, or H d t h and Local H d t h Adrnlnlshtlvr A U ~ ~ I O J iIn~CI hCinSa Thra paper way reported ill the pcrmment Cumn~issionand Intcrnationa[ As$wiat~onon Occupaliondl He+\lth Scientific Commirtcc on Maximum Prrmis~ibkLimrls Mttirilg on knzenc London. lW3. HI'CIENE STANDARD FOR BENZEKE "-9t. the maximum allowable concentratim of wtin the workplace in China is 40 mg/m'. The United States threshold ltmil value is 10 ppm (32mg/rn') W A 1 the mnic as the maximum permislrbk level in the United Kingdom.' in this I