Document B1o4eY7XoneK8VX55M7wbGkL

LIAl5^52 *L asfcisaaa itmiiinii ! Lead Industries Association, Inc. IIMM Mm As* VaA. H. T. 1C01T TMfkn: (MI) S7VS0M * -4 Hovaatoar 39. 1973 so bj sc t s p o s it x c m rut* at o c c u p a t io h . HEALTH PRACTICES K* 7MS LEAD tfOUSTIQf ' t o ns orrxcxAi. mni or ns l e a d is d o s t urn a s s o c ia t ic m, x mc . ktudtad la a docuawnt praparsd by tha XLZSO/LlA Bnvironawntal Haalth Dspartnant with tha guidsnca of tha Envlronaantal Haalth Ccaatittaa and industry specialists to clarify and fonsulata our position with raspsct to occupational haalth practicaa for laad and its compounds. It la our ballaf that a biological standard baaad on blood laad detazninationa la tha bast swans for protactlng worksrs in ths laad Industry as wall as for cosplisncs with OSHA. Until a new lsad standard is davsloped by tha Dapartawnt of Labor's Occupational Safaty and Haalth Administration, howavsr, air laad is tha only basis for datagaining coaplxsnca. Mavsrthelasa, ws strongly ramaaasnd that aanbar oonpanias adopt biological tasting. Sinoaraly, JPtila Attachasaot VJsnas P. Saltl Sscratary a Hansgsr P IIRIM.I I| l II. LI A15453 INDUSTRIAL INORGANIC LEAD PCT30WW0 -- A PROGRAM rOR PREVENTIOW i '5 Recommended OonptMoul Health Practice* for luduatrtea Producing or Uetng Lead and Re Inorganic Compound* A Poattloo Paper Lead loduetriea Aeaoctattoe, Worelabor, 1971 mr? N 3537.01 mmmmm LIA15454 ,'Mvrnnmr iti*T i rr'iiiiimi iirr;ii^rfiHiwA rjii'ii'hi a-.-iriWiiVit.'timhiiMinifcMiTn. '* nmtowcnai Thta paper u prepared aa cha lead lnduatry'a racoanended occupational haaltb practice* for induatrlaa producing or utln| lead and lta Inorganic compound*. The paper repreaenta the conaenau* of the lead Induatrlaa Aaaoclatlon Environmental Health Cnanittee at a Meeting held In South Sloean, B.C.,oc July 18-19, 1972. Thla neeting we* held apaelflcally for tha purpoa* of developing racamsendation* tdilch reflect the lead Induatry'a poaltloo on occupational lead expoaurea and tha prevention of occupational lead polaenlng. It la the pee ItIon of the Lead Induatrlea Aaaoclatloo that a biological atandard baaed on hlood lead detarnlnatlona provide* tha beat naan* of protecting the worker and determining compliance under the Occupational Safety and Health Act of 1970. Biochemical lndlcea provide m>ch more accurate aaaeaanent of poaalble hazard to lead expoaure than do air concentrat ion*. It la racoanmndrd that air aaagillng be uaed only to Indicate the neceaalty to Inatltute biological monitoring and to evaluate engineering control*. * ia ttfrlfc iil lii o m* pjppp mm. -1PW mm LIA15455 ^' A-Ir-- "-^iM^ifMr'itiiihnftiiiiwiiaiiiii^irY'nVi- * fi irr- -<'**--'^*z**-'-*---** r jr ! T-fainr -2- 0 1. IWl^.tigSltWlBI Ths adoption of biologic actloo lovolt to provide employee pro* toctloo and as compliance atandardi uodar tha Occupational Safety and Health Act ii strongly endorsed. Biological Indices of exposure to lead provide such more accurate estimates of lead absorption and possible baxard than do air concentrations. A review of a few of tha Important publications which describe biochemical tests for estimating the degree of lead absorption and the values likely to be found for varying levels of effects Indicate general agreenrotl>2?V These are described la Appendices 1*1, 1-2 and 1-3. Elkins* and note recently Williams, at al.* have reported on the . correlation of airborne concentrations of lead with biochemical levels. Elkins concluded that a urinary lead concentration of 0.20 ng/llter would, oo the average, correspond to an air lead concentration of 9.20 ag/s^. Williams reported correlation coefflcleata for lead In air and various biochemical teats as follows: blood lead (0.90), urinary lead (0.82), urinary coproporphyrins (0.62), urinary dALA (delta-amlno-levullnlc acid) (0.68). Williams also reported on the correlations of all possible pairs of biochemical results, which Indicated that blood lead and urinary lead were highly correlated (0.90), dALA and blood lead (0.68), etc. However, the Important consideration Is not how well various parameters (blocbamlcal teats) correlate with air lead levels or with each other, but what para meters correlate beat with the prevention of lead poisoning. All of Che problems and Inadequacies of air sampling, which are discussed In the next eectloo, are also present in any correlation of biochemical parameters with air levels. An important consideration la whether awltlple biochemical teste provide assessment of lead absorption or Aether more frequent topics for one specific biochemical test would provide the most efficient assessment of lead absorption. For exaapls, assume thet the results as reported by tflllleam oo the correlations are accurate. Therefore, the use of blood lead and urinary lead results, tdtleh are highly correlated (0.90), would most likely not result In an Increase In the ability to evaluate lead absorption, and more frequent sampling by one or the other may be more meaningful. It Is believed that lead in blood provides tbe most reliable practical Index of lead absorption and the use of lead In blood determinations Is recom mended ee tbe primary biological action level. The lnterpretetlon of blood lead concentrations should taka Into consideration several factors not related to lead exposure tdilch may affect tbe actual value obtained^. These factors ere described In Appendix 1-4. Useoiendst lone A. Tha frequency of obtaining blood specimens from smployets for lead analysis depends on the severity of exposure. Blood samples swat be 0 taken for lead analysis at laaet quarterly for employees exposed to lead mm pa m MfcyfaBWSAihife' ilifmA la air Imli naar 200 ai/a^. TK iu i of air measureiwnts to determine frequency of blood lead determination* may be tupplanted by the use of equivalent screening methods If sufficient evidence becomes available demonstrating their reliability. Blood lead determinations swat be mad* not lass often than every six months for any worker exposed to lead. B. All blood lead determinations aaust be corrected for the mats of circulating red cells. Such a correction may be regarded as an ad* dlttooal safety factor for workers mho have a deficient number of red cells. Hematocrit or hemoglobin daterminations provide a good basis for the correction providing the blood saaapla Is fresh, and In tbs case of hematocrit, mac lot ted. Corrections may be mede as follwi: Hematocrit: Corrected Blood Lend observed blood lead g hematocrit normal for age, observed hematocrit sex, and location. Bemotlobln: Corrected Blood Land observed blood lead x 1001 hemoglobin for age, observed hemoglobln(Z) sex, and location C. A corrected blood lead concentration of 80 ug/lOOG should be recognised as the Biological Limit Value for compliance purposes. D. The following actions should be taken depending on the corrected blood lead concentration found. These actions recognize that there may be ; s normal analytical error of + 10 ng/lOOC In blood lead determinations la these ranges. MIS' i UPS Corrected Blood lb Level 70 |ig/100C 80 pg/lOOC 100 pg/iooc Action Cl) Repeated analysis of lb In blood. (2) Investigation of employee's work habits to determine cause of excessive absorption. All the above plus (3) Reduction of employee sstposura. (4) Medical revlev. All tha above plus (5) laseedlate reduction of exposure by ad ministrative means until corrected blood lead concentration Is reduced to below 70 pg/lOOC or until physician authorltas a higher value. mi p_PMiman.il ii pw,ii liiBim mu m fin'll ' u m wm, iii.n mmm LIA15457 y* m y wm| t. Ik #u It hu been shown that blood load determinations art aubjoct to groat errora, theta determinations should ba parforaad only by experienced laboratorlea with provao ability. F. Urinary dALA way have value aa aa additional biological sx>nltorlng parameter. A finding of 2.S mg/100 nl in a frath morning specimen with a apacific gravity greater than 1.010 would Indicate the naceaalty of making a blood lead determination. There la acme Indication that lead workart exhibiting a urinary dALA of 3 a/!00 ml may develop eome minor eymptoaw conpetlbla with load polaoolng. Such workera ahould ba referred to a physlclan. r II. Airborne Lavoie The American Rational Standarda Inatltuta (ANSI) Standard 2.23.111969, "Standard for Acceptable Concent:ret lone of Lead and Ita Organic Cmpounde," recommends an acceptable time-weighted average coneantret ton foe lead of 200 pg/m3. The Threshold Limit Value (TLV) for lead, which cha American Conference of Goverimtental Industrial Byglenlats (ACC1H) had adopted la 200 pt/al. however, lead waa placed on the Intended change 1 lat In 1971. If after two yaara on the Intended change list, no evidence comet to light that questions Its appropriateness, a value of ISO pg/nr will ba adopted. The basis of this reduction la strongly questioned and la discus sad la Appendix II-1. Aa air level of 200 pg/m^ 1a adequate to protect the health of the worker If air la the only source of unusual exposure to lead. However, aa . air lead level ahould ba used only to determine tdietbcr biological eeapllag j la required end not as a coapllance standard. There are many weaknesses la relying strictly on an air value as a fixed requirement such aa: (A) A standard for lead in air alone does not take Into consider ation the potential exposure from ingestion. Variation In personal byglaaa habits of esq>loyes nay lead to large variations In lead absorption tAlch cannot be detected by air sampling. In a controlled himen exposure experi ment, Kehoe found that exposure to lead in air at a concentration of 150 pg/P (Shra/dsy, 5 days/week for 22 months) produced a blood-lead concentration con t siderably lets then predicted by Vllllamt et el.7>$. During this exposure period the mean stable blood lead concentration was 42 pg/lOOG with a single peak mean concentration (during the 17th aoeth) of 56 pg/lOOC. It it possible that this subject did not exhibit a higher blood lead level because lngeetloo, comnon la plant environments, waa not a factor la the controlled laboratory : Inhalation chanter. 1 1 (B) Air samples do not represent the amount of lead actually ab sorbed into the body because of differences In partlcla sixes and solubil ities. Air samples currently used by OCHA for caapllance purposes do not take Into account the significant affect of particle else on lung deposition nor do they taka Into consideration the affect of chemical composition and solubility of lead on the absorption of lead from either the lung or the allmentxry tract. ,s smbunMamnMis VSr-i.r.ii MU. LIA15A58 mmm iiMMi (C) Air in^ln represent only a null aaapla or on Aliquot of th total volume of air Inhaled by an Individual. Thar# aro many dif ficulties In obtaining a aanple which rapraaontt an Individual'a tlimwelghted average exposure and a aaapla of J to 4 hours la not Indicative of an Indlvldual'a overall exposure. Thera are wide fluctuations la air borne concentrations of land In the workplace and a aaapla of abort duration will nost likely not ba representative of an Indlvldual'a ex posure. Roach baa bald that fluctuations la airborne concentrations of a pollutant on a tlsn ocele of less than 1/10 of the biological half-llfa of that pollutant aro uaiaportent for practical purposes!. Short esapling periods aseasure fluctuations In airborne concentrations, tdilch stay be on the high or low aide of the actual exposure, but these high and low fluc tuations are uaiaportent for ccnpouads like lead, which has a long biolog ical half-life, loach, using a biological half-ilfa of six Booths for lead, recemended a sailing tine of ten work shifts. (D) Short tern air asapling with low flow rates, as la the cate with personal-type air saaplers, la subject to rather large errors. Cootanlnet1on of a aaall seaple la nuch wore serious than In a large oaa since that contaalaatloo will ba miltlplled several tlaes to arrive et the final concentration figure. Further, the position of the taapllag head of the personal-type air saaplar la critical. Chatterjaa, et al., found a 221 difference la the lead in air concentration aeasured atmultaaeoualy S Inches apart vertically on chests of exposed lead worksrsV In the particular case cited, the aeaa concentration found In the upper position was 181 mV while the ween concentration found at the lower position was 225 ug/w . If this teat were being used as the basis for a citation It la obvious that, depending oo the position of the air sapltr, the plant environment would both he In compliance and In violation of a standard of 200 PA/eI3..* For the above reasons It la obvious that air samplea, and * particularly air samples obtained through the use of perseoal-type air sailers, should not ba used for cospllance purposes, geesuss of the Ingestion factor a lead-ln-air standard can fall to protect a worker. Oo the contrary, biological monitoring provides an Index of exposure to all sources of lead. lecowendatlona A. Air sampling should be used only for these purposes: (a) to Indicate the necessity to Institute biological monitoring. (b) to Indicate areas In which engineering controls should ba Instituted and to evaluate the effective ness of these procedure*. ; I. If, despite the Inadequacies of air standards for com pliance purposes, an air lead standard la adopted, no citation should be Issued for exceeding this standard unless tha blood lead concentrations ex ceed the biological limit value (80 pg/lOOC). aatfutatoa r rnrnmmmmmmmmmmmm, m mm L IA15 45 9 th* ansfcushtst itan.'M I'r'iii ihfiil ; C. Attention ibcvld b directed to the use of fix* selective aplIn* for lead la olr and to tha various coapounds of load mu m provlds mo t * mmo u IU as tlasts of tha "sbsorbsble" portion of slrhorna load. * in. kocosMended Industrial Prsctlco A. Controls v r- a "> ' ' (l) fewlllt tnslneerlns Coot rota Engineering control* aey Include Isolation, enclosure,iocal exhaust ventilation end shell he the prlaery aeeae of reducing lead exposers. (2) Spec If lest Ion* Onder Which Nnwul Protection Device* Should he leeulred The use of personal protection equipment shell be required la the following ctrcmsetancea: (e) [hiring the tint period necessary to lastall the is* gloeerlng controls end to Institute the work practices re * quired to reduce expoeure sties necessary. (b) In work situations In dilch engineering control aethode end work practices are either technically not feasible or feasible to on extent insufficient to reduce the expoeure to or below required Halts. Kesplrstort used shall he approved ,, by the US Bureau of Mlaee for "dusts and fuses not significant ly acre toxic Chen lead" and used lo accordance with the procedures outlined la the Besslratorr Protective Devices Manus 1 10. ---------- ------------------------------- - O) Work Practices end Procedures (a) Adequate washing facilities exist he provided. (b) Street clothes and soiled work clothes aust sot be stored la the seas locker. (c) Lunchrooa facilities aust be separata froa lead pro* cessing areas. (d) Shower facilities Bust be separate froa lead processing areas. (a) that suppress loo coapounds or water should ho vend le dusty areas to alnlalse airborne dust. (f) Dry sweeping should he avoided by the use of vncuua sweeping when feasible. (g) Clothing control le an integral pert of expoeure coc troi. 1. Steps auet he token to prevoat coatealaatloe mP wmmmmrmm PPPMiiPW L1A15A60 lUtHUM r~ irrrtiiiiii-' * -7- of worker*' ham and falllM h; contasUnated clock* U*. I. Protective over-clothlng thould he provided for use In job* where clothlnf contamlnatioe bp lead la a significant factor. <h) Smoking, sating and drlnklnf la lead processing plaati ehall be prohibited except la (pacified "clean" area*, ImokIng materials and foodatuffa ahall not be brought Into load processing areas. (1) Employees must practice careful peraooal hygiene. Care* ful washing of Hands end fingernails prior to eating aad aboverInf after the work ablft are important coftenante of exposure reduction. 1. Medical Aspects (1) Medlcel Examination* (e) Prs-employment- All prospective employees *d>o will be exposed to lead aball have a pre-employmeot medical examination. Special testa shall Include a blood laad determination, a urinary dAU determination, aad bane* crlt or hemoglobin. (b) Periodic - All employees exposed to lead ahall have a medical review at least annually. Tha content of the medical review ahall be at the discretion of the physician but should include a review of blood lead and urinary dALA records, medical records and. If Indicated, a personal Interview. Detailed physical examinations should be undertaken if warranted by the medical review. (2) Treatment Medical treatment for lead polaootnf should not be necessary If tha practices outlined In this document are followed. However, the following raroa--ndatlona regarding traatment art made: (a) Bo specific medical treatment should be undertaken, unless specific symptoms of lead poisoning are present. (b) Intravenous EDTA la tha recommended means of therapy when treatment la Indicated. However, oral EDTA treatment bee been shown to be of benefit*^. (c) The prophylactic uee of oral EDTA, sometimes called "preventive medicine" la strongly discouraged on the grounds that prolonged used of EDTA may have adverse con sequences and such use masks tha nsed for or dlscouragss proper In-plant preventive corrective measures. Accurate medical and biological monitoring records of employ*** ex posed to lsed shall b* maintained by the employer. These records should be retained by tha aaqiloyar at least 20 years or for tha working life of tha employee. m r<am wmmf A mafWfcfttaiUWHIl) LIA 15 46 1 * D. Wtmtm Labels Caution labslt ahall bs affixed to row material* and products containing lead compound* din tha aatarlal changes ownership and din inhalation or Ingestion of fwci, dust or powders could result In dangerous absorption during use. The labels should state: CACTI OB coirrAiis l e a p AVOID VKXSTVK ABD BUATSIISC TOO ARB DOtT to r noumczD mux* 5 If a description of sp^tcas resulting Iron overexposure to lead Is required. It la recommended that the following wording be used: Effect of Overexposure: Prolonged excessive abeorptten nf in organic lead bp Ingestion or inhalation of dust and fuua nap causa abdominal pain or what la aoMtlas* referred to as 'lead colic", ustalllc taste In mouth, loas of velght, pains in Che uusclts, auacular weakness, constipation and nauaaa. Tha sim ilarity of thass sy^tons with those of other Illnesses requires that excessive absorption of land be verified bp medical ex amination and analyses of blologlcol specimens. Shin or _SJ2_ Contact: For inorganic lead compound*, absorption through the skin la of no practical Importanoa. Emergency first Aid Procadures: Ooimportant for load. t .i ii'MAtai i mas^pa. m [?. MJI BWfJiWM MP'i* PlHjllllMIH.illl.11,1 II.. WWU WIPWIPWPPP'I MIMf i-BP* SMWiW wmmmmmrn L IA15462 c .u~- ,t.- .. .,*/. ~ -- w -- ~ ~*e. - -. _ -*- . AppMdl* 1-1 lw|U Of Lead la Blood And Load In Orlno toportad By Kahoal. (1) Load la Blood Koraal (or uaual) - 0.01 through 0.04 ag/lOOga. Abnormal but salt - 0.0S through 0.07 ag/lOOga. Botoatlally dangaroua alnlma - 0.0B ag/lOOgm. (I) i.f Oriao Boraal - 0.02 to 0.10 through 0.1S ag/lltor. Dangaroua - 0.20 ag/1ltar. = mr m *mmmm L I A15A63 ^yfiritinlH -10Apfaitx 1-2 Of U*d In Blood And Print, Urinary AU, And Orlnary " Coproporphyria Kaportod By Tht rollovin* Ult Of Sl(naterlM:> llAfWMir, DmM Nlf, Cr* Nmyltl O. MiM, r,t\ C%. mi el M.K. WtllUmi, tai<w Arhnel ad Hfftwi. tUtfifi * Im^m. T. O. F, Hadwt, Iwprrtal tawhlai ft.. md el RrtotaL R.C. flrewee. MtrT ^ N^eiKW ?m. ILL MrCalftea*. Itotoeredr ef Hrtrnlie. A. A. TVwnpree, VMitH (J4. <U. I> Kmwf. VH*H Ud. R. L Fwiili, UklwrtFr f Aieettrdam. R. Crwr. tr # Guht(|. P. A. I. furry. AurttUd (Mtt Cr. A. OaMteri. t^Hii gttv el Gtorfre. T. Aerate. lMmv f LC. VlflM. Ddurylt r Ultra. IL Trdwd, p Part*. R. A. KAw. Wwrttr M Ct* itwwt fl, I.A.. L Ktof. MttnMjf ff MaAtitor. Apph I* run Wrt There to a I#w rid ftoeMttofto Cwwdrdlrt, r iWn CWti^ Am, for OTA, Nm Imi M AA C D Tret Vtorvwl 1m*.... br.iWT. r ,r 1 UMIm*.. thtaary torn* Ortoere eapr Ortoary d eitoelar nhut arid < *./ IM mi. < *./. W-W ./ |M mL <im m n. ItO-MOat-ZL o.t .' 1W mL *.-> f IM mL M-1M / IMmL iw-m M-rt. >44-4. M* ./. >IN/ IMmI >w.A >Ut4tat/l 1-4 ./ IM k L IW at. Rtor* Ml ertoar* M MrrMMfoM ear W retted * air vhra rirrlrf eto to tAonlohri r^irrtMd to toe ib Ab Ub m ! n er, rrrm t MT mj be er- Urtoary aar*toa af nerlte giertoi Wm Am Lttt are eftteUdfeto aad A-N he repMed: N-kwr r irpwfo* "to1** toairahto. A ww Mereme* <4harmtofto to topartart a*d*tore! #tow; tomi lunM(lAta ewrertorAtoa to rauMir lead to toed petoeotoc tot he aMectotoA tiA eategrey for D. IWte* l,ew>fAi1 (mii, A etUI eead. ere toee ithAh thee (he KAa Aeto to the Table, ad err eat drlcah The leer arMtran etoffwrtoe ear (A) AHeorpttoe fae^ to the "reneeT papelattoe he* there hea Wm * m>a i ttoeel er Ah i>1 eapoevr*. <Wl torMMd P>aorpto re*Kto fret aeeyfAleeal er toeanaal to Mate which la eccMeheralto acceptA>W. Al three to^ela el toed toeeepilee the dld eyva^ tame Hated helev. which ere t$mmm to --Aar at efoer eea^lalaU. ere eat Ptrfhrttoto to toad. Id toninl ahaerpttoa frew* eaaeeatoe wieidl--il er ether a^ageie toiA p u t ha aaeactatad wtth mild < *** or et**a (ere hetovt. er. rarely. wCh eeretv eympriM or iiim. Free to IW decree d eemprtoe tad dfu three toeele el Aherrptar are eex cepd>to hrcaaae d the prchlhtr el lartt epleadee ead leal Wm fill Hmy ran el*rtdtoa freer rccafwittoral er tohrr e^eaere la ehdrh Mdld. # 1 mreerr. r> w^emna eel aleo totp^erva er^urlx are torreactogU prtowhto. Ml l Jr.J I IIMIMM><>||| II.. IIIW I lnp*pi.H(jiUUJ*!Hll^ . UH iwyngfmmmm i.-r Wn:-- rdai n LIA15464 -IIAppaadia 1-3 Unit Of ImI Absorption Ralatsd To Cffacts As Asportad Ja Tsbls A-11, Of Tho Dociaaant, "Airboros Laad la hrifMtln", By National Acadaaqr Of Sclaaeaa*. Cshc. OftiiWT { V W pirfmt,! l >IM >1M lMf tobbMN I mmmmmgmmmm ............ LIA15465 * -12- Appendlx 14 Interpretation 0( Blood Lead Concentrations^, The folloving factor* muat b* taken Into account la Interpreting a given blood lead eeoeantratloo: Proper collactloo of wbol* blood itaplt and rallability of laboratory performing the analytic, hema tocrit value, current or recent adminlttratlao of chelating aganta that teag>orarlly dacraate blood laad content, pretence of hemolytic anemia, and period elnct termination of undue exposure, Long-term contlnuout adminletrat loo of a chelating agent, euch aa D-panic11la mina , auppreaaaa blood laad content to the normal range during the dlure<la of lead, and Intermittent chelation therapy la aatoclated with fluctuating blood laad content. t Harked changee la the mesa of circulating red blood cell* may Influ | ence tdioleblood laad content, la that 90t or more of the laad la blood le attached to the red cell*, la peraona with moderate to aevert i anemia, clinical evaluation of the algnlflcance of a given blood lead content may be facilitated by correcting the obaerved concentration t to the approximate value that would ba expected if the pet lent'a packed red cell volume (hematocrit) were within the normal range. The relevance of such correctlona must, however, ba aaaaeaad further through the usa of other indices of laad absorption and adverts af fect* (e.g., response to chelating aganta and dALA excretion). Sub jects whose high-level exposure has terminated several months to several year* previously stay still have evidence of Increased body burden, aa measured by the CalDTA mobilization teat end blood laad if concentrations that are minimally to moderately Increased. ' piii)PK|Wiij Jipi)mwmm/pmmm'mHmmm^w>wiqiww-|.iiuiiii,i.iipr: mn .rnmmtm*******mm, LIA15466 rVittiaMattlmiihammBiaimfhartBda^ aitf -13- Appendlx TI-1 Di*cu*slon Of Tha Proposed Induction Of Th TLV From 200 pg/e3 To 130 pg/m? The rtfuctlM In the TLV by the ACCIB he* resulted primarily (ran ths work of Williams, at el.3. Th* Documentation for th* TLV for Lead *t*t**i In an extremely thorough study of atawepherle load expoeur** and biochemical criteria, Williams *t al. found emnung 39 worker* In England high corralat loo coefficient* betweea air concentration* and blood load (r-0.9); urinary load (1*0,92); urinary coproporphyrin* (r~0.82) and urinary dAlA (r*0.98). Lowor correlation* were found for punctate (atrlppled) basophlllc count (r-0.45) and percent haaeoglobln (r-0.09). Further ore, they obterved that In every can* the upper 93X confidence limit considerably exceeded th* eaf* Halt*, dm th* air llnlt 1* 0.2 *g/*J, but approximate* It when th* air limit la 0.13 mg/m3. In view of these more recent data oelng Improved biochemical Indicator* of reepooa* to lead exposure, although originating In Creat Britain, but clearly shoving that th* TLV of 0.2 ag/*3 ha* little or no safety factor for some workers, a TLV of 0.13 mg/m3 a* leas la reesaetended as a standard for exposure to Inorganic lead dust* and fuse*. The study by Vllllama and coworkar* represents a significant con tribution to th* area of occupational exposure to lead. However, It Is our opinion that th* data and statistical treetamnt have not been adequately evaluated and the appropriateness of reducing th* TLV for lead on this basis 1* questioned. The blood lead cooceatratlon predicted from air lead concentrations of 130 pg/m3 and 200 pg/m3 wer* calculated from a regression equation utilising 39 pairs of air lead and blood lead values. Th* blood lead concen tration predicted from the regression equation describing th* regress loo of blood lead on air lead for an air lead of 200 pg/m3 was 70 pg/lOOnl with 93X confidence limits (expressed for single determinations) of 49 and 92 pg/lOOal. The blood lead concen tration predicted for an air lead of 130 yg/rn3 was (0 pg/10Gml with 95T confidence limits of 39 and 92 pg/lOOal. The basis for the suggested reduction In th* TLV form 200 ug/m3 to ISO ug/m3 Is that the upper 951 confidence limits for blood lead and other biochemical parameters at an air lead of 130 ug/ m3 do not exceed th* "safe limit*" for the biochemical test* while the upper 931 confidence limit* at an air lead of 200 pg/ m3 do exceed th* "safe limits", Th* data do not justify a reduction for a nunher of reasons! (1) Confidence llmlte are dependent on the degree of scatter of th* data points so that a large amount of scatter result* In a vide confidence band. *lllhmmui*iiim<md II it wnmempsep 9SW MiWi'UUJwyM' m L IA15467 w!..^-..,.^--.^-....^, - ...... -- ^--^.-- - - v - -- - la iij^--f lirilttiii f* nfriffi s -----------------.---------------!*.------------------- Appeodlx 11*1 Continual i i (2) Confidence Halt* are dependent on the maeber of eaaplca taken. An experiment Involving a email number of samples will provide a wider confidence band than an experiment tdilch lncludee a large mumbor of eoplaa. ()) Confidence llmlte vary (Increaaa) with magnitude from the mean value (of x). The narroweet confidence band la at the mean value of air lead which appear* from the plot of the data to be much leee than 0.20 ng/nJ. Therefore, the confidence llmlte at 0.20 ag/a3 are much wider than at the mean air lead value which was approximately 0.10 to 0.12 a|/a^< la the article, the valuea in Table S llated ea maana are actually predicted valuea, not mean valnee. (A) The confidence llmlte are for a alogla determination rather than for the regreealoo line. The confidence bend la much wider for a alngle determination than for the regresalon line. (5) The reaulta are heavily Influenced by plaetlc department employera where the lead In air coocentratlona were 9 and 12 pg/m*. If thla clump of low pointa la enlttod It la doubtful that the regreealoo of blood lead on air lead la slgnlflcmt. Further, exaalnetIon of the deta point* (hove thet there were mo caaei In tdilch the blood lead vaa higher then 80 px/lOOC when the air lead waa laaa than 200 pg/al. It la apparent, than, that these data do not justify a reduction In the TIT. If anything, they support the 200 pg/a* figure. mmg? rnmmmm. LIA15468 -15- t mtUKB 1 Kehoe, I.A.: Occupational laad poisoning 2 Chemical signs of tba absorption of load. J. Occup. Had. 14:3, 390-396, 1972. 2 Lens, K.E. at al: Diagnosis of Inorganic load poisoning: A atataaaat. Brit. Hod. J., pg. 301, Nov. 23, 1968. 3 National Academy of Sclancaa: Airbora* Land la Perspective. National Academy of Sciences, Washington, D.C., 1972. 4 Elkins, I. I.; Chemistry of Industrial Toxicology. Wiley and Sons, New York, 1969. 5 Willlams, H.K., King, E., and Valford, J.: An investigation of lead absorption In an electric accumulator factory with tba use of personal smiles, grit. J. Indust Had. 26:202-216, 1969. 6 American Conference of Coven--ental Industrial Hygienists: lead (TLV Document ation for LEAD final revision Included with letter from 8.1. Stoklager to J.P. Cole, August 13. 1972). 7 Kehoe, K.A.: The metabolism of lead la men In health and disease The Barbee lecture, 1960, J. Boy. Inst. Tub. Beelth Hyg., pgs. 1-81, 1961. 8 Bosch, S.A.: A -->re ratlooal basis for air sampling prograss. Amer. Indmat. Byg. Assoc. J., pgs. 1-12, Jan.-Feb., 1966. 9 Chetterjee, B.B., ct al: The location of personal sampler filter beads. Amer. Indust. Hyg. J., pgs. 643-643, Nov.-Dec., 1969. 10 American Industrial Hygiene Association, American Conference of Governmental Industrial Hygienists: Respiratory Protective Devices Manual, AIHA, AOCIH, 1963. 11 Bell, R.P., Cllllland, J.C., Noland, J.B., and Sullivan, B.R.t Effects of oral EDTA on urinary and fecal lead excretions. Comparative excretlonary studies with l.V, therapy. Archives of Industrial Health 13, pg. 366, Apr., 1936. 12 Kehoe, K.A., Cholak, J., Hubbard, D.H., gambech, K., end McNery, E.K.: Ex perimental etudiee on lead absorption end excretion and chair relation to the diagnosis and treatment of lead poisoning. Journal of Industrial Hygiene end Toxicology 23:2, pgs. 71-79, Fab., 1943. 8f ............................ . .1' j u h h u m j i 1 i nu mm