Document rBD4RDVDv0KGJZ11g3E42ovda

-^ jOCA '//.la/utks ^^9 OH CW. Ora, liMf. W. SI 23^241 Thetmigration of lead from paint 'ftt^:t^fhe:;'rat;ga^iro-i:ntestinal tradt " By J. C. Gaga and M. H. LitcMtatd imperialChemical Industries ltd.. Industrial Hygiene Research Laboratories. Aldertty Part, Cheshire SwwMrr The ttugraiion of lead from too paint lilim during their passage through iIk rai gastric intestmai tract hat baen investigated. Both painu contained 2 per cent lead mi me dt ted Him, one as lead naphthenate and the other as lead chromate. Diets containing I per ecm <4 the dried Alma nere adtninisiered to groups of rats for a 12 week period: other groups recenoi diets containing 100 ppm dead as lead naphthenate, and 2Uu JO and 100 ppm lead as Irad nitrate. All groups of rats remained in good health. Lead deiermmeiinm ware modt at mwnah on tamplrn of bone. Wood, kidney, iiser, bile end urine. From e comparison nf me analytical results it has been deduced that about onedtilf of ihe lead in the'lrad naphihenaic paint, and about one-uuarier in the lead chromeit paint, migrates from the Aim under the es-renmental conditions, it is concluded that tha present regulations controlling the lead coniem oi pamis intended for surfaces aeeeisibte to children are adequate to present future eases oi lead poison ing from the ingesuon of paint film. Kej TyrTM alikkyd coating 3S drier Prime jwywnii chrcnfeiwanfc Pmfttnietr fi trimurity esuttmUfi wuk nuuvnuh mgettero! toxicity La migration do plomb a partir do* fouils do pointuro dans lo canal gaptro*intastinal do rat Mcmmr On a ctudie la migration de plomb A partir de dew feuils dc peinuire pendant leur passage a tracers le canal gastro-imesiinai de rat. Les deux petalures eontiennem 2 pour cent rtc pUmih dan* 1c feuil sec, Pune sous forme de naphtenate de plomb cl I'auire comme ehrotnaie de plumb. I>es regimes comenant I pour cent de feuih secs cuient donnecs aun groupes de rais pendant urn periods de 12 semaincs. d'autret groupes reeesarent dm regimes comenant tin . parlies pour million dt plomb comme naphtenate de plomb. et de 20. JO. el I0U panics pour million de plomb eomnte niirare de ptomb. Th u s les groupes de rais nnaaicm cn honor same. On a ihncrmine. par imervalles. la leneur en plomn ain rvhaniilkms d'os. sang. rein. flic, hile et urine. Par conssderaiuM des resuliais anuiytMiues. on a dedim uii un pen |Mt> de la mouse de ptomb dant la pamtua* A naphtenate de plomb. et im peu pns du auart dc ptomb dam la peinture i ehmmate da ptomb. doriom migrator sous les conditions canenniemaicb. On couciin gire tes rdgtaramts guussrnom la leneur en ptomb das permutes, dCMinees aua surfaces accesihte* aua entamf soot sulliuims pour evircr a I'afenir uo eas d'mloucaium pu> le plomb few* de Pinpuatun des reuib de pemtiire. 2M /d-rd-y/ : ..;:i,, i-u*U,.slt?. VllitATIIIN (IF LEAD (-HO* AAtNT FILMS 2?7 Oas Wandarn von AMel us Anstriehfllmen in dan Magen-Darmkanal . von Rattan > ' ^irwmmcn/uiAtmt Die Mifnittw iih i Hlct j im iwct AimnchAIntcn wlhrenU vcuws OvdipAfa dureh den nm Rjuvn wurte unicrvuvUI, Unde F;iihcn enthiefien 2 Ptiwcnl Hlci i TrncWnfm vhi I, die cine jlv UIrmarHihcnM und die andcrc all BIcKiirumai- WjhremJ iMi<lli<i;i'ieen Pcrioden urden Gruppen von Ratien mu | Proiem- del Troekcnrilnn .unaltfcnUcn Oijicn nefuucri: andere G Happen erhieitci) Diaicn mu 100 Teilen p.m. Blei ai> N.,phiiw.ui tmd :n, 51) und ltd) Teilen p.m; Bki all Nitm. Alie Ratienfrumen Wieflen ewunili nieiheviinimiinjten nurden in Zwnchenraunien an Protea von Knucnen. fcllul. Nitre, I CPC1. tulle und Grin vorfenommen. Auv Vergteeten der analytuctien Rciuliate wurde pcwnlnwcn. daw cu*a dw lljlfie da Olciei in der Wetniphitenatfarte und eiwa tm Vicrtcl in der Bkiuhnunaitarte umer den cxpcnmenwUcn 8edin(unfen auv dam Film wandtn. Ea vurd gdtilpen. d.isv die teviehenden Benimmunatn fur die KomroHe da BleifcAaha von I jiteMiidle iur Kimlcm moingfadion Oterflucten varfcvclicn Mini. fenufen. um in Zukunri I jlk v imi HlKiniisiriungdundi inpaAMHi mm FarMilm iu vcriiuicn. Murpiinta ceraae Kpecoeaua saanmi a aeayaiWMO mh ii*u w bm spasm ague Friviiur I lecnenunnnaca unrpetin* caamaa any* . apecoeuMa nmH non na npoaoaa etpes *c:iynmiKuuicnHua rparr spue. Ode apaeni coatpwinn-2 npoucnra cannua a eyaod naenae. onus n mm uaOrenoaocannuoancraa earn a apjrraa a auae apoMoaoancaora cauniui Jlncra coacpoaaniBa 1 npoupur arm cyan* nneno* aaaanaca rpynnau epwe a retemie 12-in raaejtk: apjrrne rprimu icpwc muqruuui Suer? ctuctnainyio 100 vacre* pa MaiMMtN c mh ih a mj k MMgreiiocMmiiDmcroa teas a 20, S0. 100 naeieO na Mutuum eaunua a mm: awnuKannuoaucreM can. Bet rpynnu apuc oerannck u o po u h mu . Onpenenenne eaniiua nponiasanjiacsi neiiwi npOMCsyrm apeMtnu a oSpawaa eoeru. apean. noon, mmsim. aairen mo v u ; Cpaaacaae Maumranaenu prqrnbTaToa nseadam t o oaano nu.-ioauMM emiiiiia a epacae eopepaaiwia uaOTeuocaiiniioawcryio earn u ocoao wseprn cenmia a epaewt eojepaaiuca atHMumoaucnuB eanueii. MurputmeT m nneueu npu yeaoaaaa ouura.: Jenaere* sacimaim at o eyoieereyiaum TpMoaauna tOMTpoaupytmime cojetiaanue eaunua a npaccaa nptManaaaeMHX saa noaepanaemd aocr-mtuu sa sml, MnoTce aueniTounuoMi ana iipejOTaiMiisMaa a OjrajnaeM eapaaaa orpeaDenna eaMaaoM iiyreM rnoianun spaconmiA naeiom. , ImtrodnctiCM Since the turn of the century, there has been a progressive decrease in the incidence oT occupational lead poisoning, in 1930 there were 32 ratal cases notified to the Factory Department, but none was reported over the period 1957-1966. Non-ratal eases fell from 233 in 1930 to DO in 1966. These improve ments ! have been in part due to the enforcement of regulations under the Factories Acts, and in part to advances in education and in the dissemination of information, and to a greater attention to occupational health. Only a small proportion of the reported eases are attributable to the applica tion ofjlead^ontaining paints. There have, however, been numerous cases of non-occupationai lend poisoning, mainly in children, which are thought to deme from the ingestion of flakes of dried lead paints detached from treated uoodwjork. In Chicago alone, over the period I95M96I. 429 such eases were recorded, of which 67 were fatal1. Other cases have been reported by Chisholm ASfa?|iS0nsi:aftd by .MOneriMT m if. This high incidence of poisoning may be duetto the high lead content of paints formerly used for interior decoration and to the friable nature of old paint films, which renders possible their disintegration into small {amides with a large surfice area when chewed and swallowed. It -_.J 238 j. c. oACii: i i.. * I'A has also been suggested than young children arc mure m:iw ih l - n> lead than are adults*. With the object of protecting children the paint industry gave a voluntary undertaking to the Ministry of Health in 1963 (hat paint containing' ir..ie than I per cent lead on the dried lilm should bear a earning labei :::uic.::;.".g that the colour should not be applied to toys, furniture or interior >urtacc> which might be chewed by children. Subsequently the labelling of surface coalings intended for toys was controlled by the Toys (Safety) Regulation". 1967 which limited the* lead content of the lilm to 1.1 per cent, reduemg to 0.5 per cent in 1968. , In a previous publication', [he migration of lead from polymers m the gastro intestinal tract has been studied by incorporating the ground polymer into the diet of rats and then measuring lead in tissues and excreta, and comparing the results with those of similar experiments in which a lead salt was incorporated in the diet. By comparing the amounts of lead absorbed in these two sets of experiments, it was. possible to relate the diets containing the polymers to the diets containing lead salt, and hence to estimate the extent to which lead migrated from the polymcrimo the gut contents. It was concluded from these experiments that the difficulty 'in masticating these materials prevented any risk of lead poisoning from their ingestion. This limitation evidently does not apply to paint film, so the investigation has been extended to ascertain the extent to which lead can be mobilised from a paint lilm. and to confirm than the present regulations provide an adequate protection Two paints have been included in the investigation; one containing lead as a drier and the other a lead pigment. Experimental Materials investigated ; The paint used in this investigation was an olf-white gloss linish based mi an oil-modified alkyd resin. It contained cobalt drier without lead. To one portion was . added Middle Orange Chrome pigment to produce approximately 2 per cent'Tcad- ra the dried film, and to another portion was added lead naphthenate drier to produce approximately the same final lead content. Preparation ofdiets The paints were brushed on to pieces of tared rice paper. 75 " 50ciu. and allowed Jg dry focJhrec davs. After reweighing to assess the weight of the paint lilm. the sheets were placed in an oven at WC for three hours to render them brittle. Unpaimetl nee paper was similarly dried for use in the control diet. The painted and control rice papers were broken up and hqmogenised in a small volume of water and the resulting slurry mixed with malt extract and com oil and then incorporated into the standard rat diet* to give a linaf eoneemratnm of l.pcr cent paint, lilm in the pellets. The rice paper content of the dm was about 0.5 per cent, and the same amount was added to the control diet. The diets based on the lead chromate and lead naphthbnate iilms went found by the analytical method described below to contain 192 and 190 ppm lead respectively. 1`or the diet;, containing lead nitrate the sail was' added in aqueous volution; lead naphtltenate was dissolved in the com oil. The control diet was found by the method described bdow to contain 1.3ppm lead. -i j. . 0007-SWP-000005835 6. 1969 <J) mio k a t io n u f l e a d f r o m f a in t FILMS 239 Animal experiments The animal experiment'! were performed ns previously described*. The diets were administered to groups of 30 young male albino rats lor a f 2 week period. Ai intervals animals were killed and samples of hone, blond, kidney and liver ncre taken for lead determinations. Analyses of bile and urine were made at 4 and 12 weeks: earlier experiments with rats receiving lead salt diets had vliowni ilut no appreciable amounts of lead were excreted in bile earlier than 4i weeks. The weight of the rats was measured at weekly intervals throughout the experiment and the food intakes were recorded. At the end of the feeding period blood samples were examined for haemoglobin content, packed ceil volume, white and differential ceil counts, platelet count, and for the presence of stippled cells and reticulocytes. Bone marrow was examined for punctate havophilia and for immature red cells. The determination ofhem! The determination of lead in liver, kidney, bone, bile and urine was made by the methods previously described4. Increased sensitivity in the method for blood was achieved by carefully evaporating a Smi sample to dryness with 2ml nitric acid and ashing ihe-residuc at 5Q0*C. The ash was dissolved in 3ml wmer and 10ml SN hydrochloric arid and the lead was determined by the colorimetric method. The experimental diets were ashed by the method used Tor bone and the residue was dissolved in 0.3ml- hydrochloric acid and 0.23ml nitric acid; and diluted to 10ml with water. The solution was polarographcd with a Cambridge Pen-writing Polarograph and Univecter over the range --0.2 to --0.8 v. and the peak heights obtained were compared with those of standard lead solutions. BCsoltS The concentrations of lead found in the tissues, bile and urine of the test and control rats throughout the experimental period ate shown in Tables 1-6. In a|l experiments the rats remained in good condition and no significant difference was observed between the growth and food intaka of test and control animals. No changes were observed in blood or bone marrow, indicative of early stages of lead poisoning. The tihitirptiau of leadfrom lead salt diets Lead' nitrate: Table 4 shows little difference between the urinary excretion of lead jby control animals, and by these receiving the lead nitrate diets, even at the highest concentration. These results confirm an earlier observation that urinary excretion in the rat ammot be used as an index of lead released into the gut*. The concentration of lead in bone; kidney and liver tissue increased with Use dose. ith kidneys and liver a rise is apparent within the first two weeks and the concentration remains fairly constant throughout the 12 week experiment..The accumulation in bone is slower and the concentration appear* to reach an approximately constant value at about 8 weeks. The concentration of lead in the blood (Table 31 shows some'eorrdatian with the dietary concsntra- :40 J. r. GAGE. LT At. ii tCi a TuMe I Ltfasi erxHmt ttf tame Dt .-- ..(j 1 A ' i Control Li-ad mirm f 29ppm at Pb <| JUppni l ItiDppm, Lend UMfdukemie as PP IQOppm Lemi fimmts Chrome msmem NaphitKnaiC .. I.B3 II01 0.53 (4> 0.93 U) 0.94 141 o *3 ui 09012) 1.36*2) J 31 l2) i /*: 114(2) 3.00(2) 5.11 tZi '? % i2 .. 4.41 (2) 6.90121 5.:: i2> 7 34 l2l : 3.11(2) *l 0.03 (2) 2.46(2) 1 1.52(2) 4.34(2) ' 2.13(2) ft. 17(2) 5 20(2) 9.23i2l 6.; ui 4 61 12) 7.57(2) Analytical milii am nproMd at !*f/g act weight, and arc the mean* m OcicrmmjiM*m n the number of anwnals mdacsted in pammshem. Lewi fiwiw *f Others ' Diet Wackt o 24 8 J* Control .......................... Ltvd mirmr ` f 20pvmi at Pb 4 SOotn t,100ppm Lemi mfduLfmte asFh louppm Itmivantra Chroma pigment Xaptnhanaie ... 0.45 (10) MM do 0.24 (4) 0.40(4) .0.70(2) 1.31(2) 1.53 (2) 2.23 (2) I.(M(2) 1.78 (2) 1.00(2) 1.12(2) 0.99(2) 1.78(2) 017 (4) 0.22(31 0.67(21 ' 0.79(2i 1.25 (2) 1.16t2) 1.80(2) 1.3912) I.MM2) 1.8312) 1.05(2) 111 (2) 0.98(2) 107 (2) Amlyiiol iwlt$ arc e&prcued as 141 ct weight, and are the means ot determination* on the (tamper of animate indicated in parentheses. 7aMr J Lewd etmtent of tinr 0 ; 2 4 8 12 CMtrai ,. Lewi mirme f 2000m a Ph ( 50mwn ^ Ituppm Lewi mpkiknmie as Pfe IflUppm Lewd (mines Chrome pipnafit NaohUunaw .. .. i 0.08 (51 .. i . i .. 1 i *r 1 i aii(4> ! 0.21 (2) 1 013(2) | 133312) 1 j 018(2) I ! 0.17(2) 1 013(2) 0.12(4) U.)9(2) 018(2) 0.2012) 0.28(21 Oil (2) 0.33 (2) 0.12(4) 0.14 (2l 012 (2) 0.30(2) 0.37 (2) (1.28(21 0.29 (2) 0.31 (2) 014(2)- 0.31121 0.19(2) 0.30(2) 013 (2) 0.321) i Analytical rcHdea an enpraawd os s*&g wetwdgta. and arc the mean* of detcrminaoon* on the manner of ammate firitinnmnil m pirrmitimii Jseri^ 0007-SWP-000005837 1969 i?) MIGRATION OF LEAD FROM FAINT FILMS TtUt4 , leadeamteata(ariar 241 Week Ciwinil I salt dim (as Pbl i- Lead : I'j iiij i Uk i* | naphihcnaia '------------------- I.. 3Sjppm : JOppHi | JUUppm [ loonam ; plgmcM ' Nainuhtnasr 096(2*1 4 0.72(17) 0.73 120) (.23 (191 0.0* (22) 1.01 (ID 0.64 ( 0.93(17) j 1.20 (ID 079 03) 1.26 (30) -092 04). ! 1.22(30) 1 1 2.13 (23): 1| 0.61 (23) 0.% (10) 1 !12 0.67(121 > 1.07(32) 1.17(16) 1.79(24) 0.99 (12) 1 1.20(20) 1.20(21) 1.27(23) 0.9*132) 1.04(24) 1 1.37(31) | 1.6609) 1 10006) (.33 (26) ! 0.90(24) j l.lt (27) - ------ --j --. ----- w u b m * Dwa sn in ('*- FTM in paranthnas, urint vstam (M/rat/24itr>, _____ TaUeS Lead camtm afblaad Oia Control Lead <ww f SIr m as Pb < JQppm (.lODppm Lead aafdukraate as Pb lOnppm Lead fotat Cbnsnw pifnem Naptnhcnjit .. :: .. .. *! o 0.12(10) -1 i .. i i .. j *"* Weeks 2 0.07(4) 0.04(4) 007(4) 12 Oil 0.09(2) 0.11(2) 0.14(2) 0.01(2) 0.1112) 0.31 (2) 012(2) 012 (2) 013(2) 0.16(2) 0.24(2) 0.24(2) 0.13(2) 0.26(2). 014(2) 0)6(2) 0.10(2) 019(2) 001(2) 0.13(2) 0.06(2) 010(2) 013(2) 0.19(2) eF dtmrniBaiioes on tt ntsmbaf of animat. -_________________ __________ TaUei lead eoauaufbde w*k I Control Load salt ding (as Pb) 35bpra 30pps* , lOOppa naphthansw Paiet titan lOOppa t Chisms Naphihanast 4 i100..0011*21(11631) j'00..0010((a1)3) 1;00..00331s(l<13ll)t o mo o p i 0.10) (SO 0274024) U 19(29) 0.02(12.3) 014007) 0033(20) 013000) 12 '00*3(11) 0190(13) >0.04109) lOIOOOD 10096(1X3) 0120(14) 0114(17.3) jOOTKITJ) 0.11700) 0)10(20) 0133(13-3) Ratals are eapnmaiil as L A-.*-.;....;, imbsaia wstoma of MtaaKSad yaUsatGStoi. *dt an a sepuaM is l Fifms n paremhasas I,,j rrr -zrs-~--r. rr---7----------- *------------ - -- 0007-SWP-000005838 0 342 J. C. Ga GI ET At. jure* tiofl, but this is net so marked as if is in other tissues. Bile provides a sensitive index of lead absorption, though the correlation with dietary concentration is somewhat erratic (Table 6,t trad napbihmatr. The concentration oflead in the tissues, urineand bile of rats receiving the lead naphthenntc diet is similar to that ooserved alter the administration of a diet containing an equivalent amount of lead nitrate. The acid radical does not, therefore, affect the availability of the lead. TTse absorption ofhodfrom paitufilms Chromipigmtm: The concentration of lead increases in kidney- -J bone during the lint two weeks: in the former tissue it thereafter reman ..riy constant throughout the experiment: and with the latter the concentration continues to rise until the eighth week. There is a slight increase in the lead content of liver, but the bleed concentration is not significantly different from the control value. There is an appreciable excretion of lead in the bile but the amount in urine is ntegJigibte. The amount of lead'ln bone. kidney and bile of rats receiving the chrome pigment paim diet is similar to that observed in the rats on the fOppm- lead nitrate diet. trod nepbtbenato paint: The uptake of lead by kidney, bone and liver it much greater than that observed with the chrome pigment paint, and it parallels the findings in rats on the IQOppm lead nitrate diet. This condusiph is supported by the bile results and, to a smaller extent. by the blood analysis. There is again no significant increase in the load content of unite in spite of the consider able absorption of lead demonstrated by the analytical results on tissue and bile. The work of Chisholm * Harrison1 has shown that the daily average lead excretion in the facets ofchildren showing signs oflead poisoning'after ingestion of paim Hakes, is 44mg. As most of the lead ingested appears in faeces, it may beassumtd that a daily intake of in the region of 3Qmg lead is very dangerous, unless the lead is in a form net available for absorption. On the other hand. Kdhee* has shewn that a daily intake of Img soluble lead salt in the diet over a period of years is without risk. The present investigation has demonstrated that about one-half of the lead in the lead naphthenate paint, and one-quarter in the chrome pigment paint, can migrate from the film into the gut content, ami'Table 7 shows the amounts of the two paints which must be ingested daily TaUt7 Haari fimm ptim iogntian risim auam*piflmam Lead mehthsnut .. Tfrrashokl flmg dims) I Banger iSOm dual w%m.8 Aiw. on* | Wuighi. * . Area.au* 03 29- L 10 : ' 1.000 ** 1% s j J i S Figure* weight and surfaet area (aidraga smelt seat! of paim eoawimnf 2 par cam lead on dried Aim whim, fnpaUdiihi would ranch threshold of ssfsty pr.ha v*ry danjgroui. f I i i *? rj1 0007-SWP-00GO05839 1969(3) mig r a t io n or l r a o f r o m t a in t f il ms 243 to product the thrtsheM &nd she d&nperous Ittd intakes. The observed migration of lead from paint fibn is much greater than that recorded in earlier experiment* with polvmer**; thi* may be due to the much finer stale of subdivision attained with paint film. It i; possible that the mechanical means used to disintegrate the film was much more efficient than the processes of mastication and digestion. and the migration figures achieved in these experiments may be in excess of (hose encountered when paint flakes are ingested. The undertaking by the paint industry to limit the lead content of finishes for surfaces likely to be chewed by children to not more than I per cent is in agreement with recommendation!;of the British Standards Specification and the American Standards Association. The amounts of such paints which must he ingested to achieve the threshold and toxic amounts would be about double the figures in Table 7. With coalings containing not more than 0.3 per cent lead m conformity with the latest Toys (Safety) Regulation*, the amounts wpuld be about fourfold. It is certain that these figures indicate no haaard so long sis the film is adherent % it would be impossible to ingest sufficient either by detaching the film manually or by gnawing it off the support. A greater wad intake would be possible if detached films were available for ingestim but. even so. with paints of this type, there seems little justification for the fears expressed by Chisholm and Harmon, that poor maintenance of modem houung with resultant accumulation df'nuuiy layers of paints on surfaces acesssibw to children, may in the future constitute a heard to small children. Aduwwledfisseats , Technical assistance in this investigation was provided by Mr f. B. Hall. We acknowledge the co-operation of Dr D. G. Clark, who provided the bile- cannulation preparations. Deetmbtr IW 1. Clark. D. G- MeeKasu. T. F- and Hum. t W,, 1. lutes*, Me*. 19*4. S3.126. 2. Chisholm. J. J.. am) H. MM. BfrimtM. 19*4 W-.m ... ]. Christian. J. It.. Gdtwyex. B. 4. ani Andaman. S. I_ Am. J. PaU. HtmM. 1964. 5*. 1241... !' 4. Gage. J. C.. and LhdilMd. M. H.. M Cmmm. TtxkaL 19*4 4 . 3. Graenasrd. J. Clm. AruBw. 1964 4 269. 0. Kehee.R. A.. An*. Emr. IS64.4 3SS. _ __ 7. MeneriofT. A. A.. Koumada. Q. Clayten. . E-. PStrfsk. A. D, Renwiefc, A. C. G.. 4 and Rotars. G. 4. Ani. Bit. OUlde.. ittd. 3A t. 1 Next month's Issy. \ are expected u appear*^tha'Jprif ****** "Esiarier <tamitoty:r ceathp,** /. E FaOard. "Eswhy Mtitar firirtn la Saatt Affta." hr 4. MWfar. -i ----------- -- t -t -t -* rtimim " It * f a . rim*. i ------ -- a-- a..-,\nimr . . .. 'J " -..y.-r. . . .. .I -- .............- . - . ........ ..... . rf`; .~rs38?.: ' ?. - - ~^j c 3b s e b b f x ' ns-L'i-i....... ~----------------------------- ---------- ... / ....... - - ---- IT. 0007-SWP-000005840 ..