Document qa4xdR4j4533qG9RepbDg3jNR

' /,** '7** A'^/ . v:^.?-^...-_ ;,-;gj^r ?\ *^ , U^V? . ^^iciUil LEAD INDUSTRIES ASSOCIATION, INC. Jt MADIION AVINUI NfW route, H. V. tooiy lUMM - A**A cooa ill > OINMN*9mTM. INW.MMUUMHI VM*IIHMWMM9 MOM ft. T4VI. ............. WiAMUM irm. r*UAU*T. n frAVIItMtMO MVMT*. T*+*rl**mVMKcJ**AWMiMwMm '3 Tot U. 8. ud CidUD MnNrt of the LXA Health and Safety Cceaaittee Ret Teetlnoey of Dr. Robert A. teboe, January 19, 1967, at Public Bearing rt Propoeed Asblent Air Quality Criteria 7frc Ccegaccvealth of Peaaaylvmcla, KarTleburg We hare obtained for you a copy of tbe unedited tranee rlpt of Dr. Kahoe'e tatesent together with the queitloca and enewere. Aa toon aa pee lb la we vl 11 aecd to you a Corrected aod edited copy of Dr. tehee'a atateaent, but tbla will require nucb aore tlae to obtain. Aa you know, tbe bearing record i la being kept open until Pebruary 10 and written atatenenta ujr be aeot to the Air Pollution Cuaclaali at any tlae up to that date. Written latesteta abould be eddreaaed tot Melcola W. Scboeoly, Secretary Air Pollution Ccamlealao P. 0. Bo* 90 Barrlaburg, Penney1veola 17120 1 ?,*[* i^VS'VJjv:>,ci,',^vr '-'uhr. .c`. In our opinion. Dr. teboe Bade am effective atateaaot and thoee of ua preaent 'a -; at tbe bearing, feeling that Dr. tehee 'a reaarba could not be bettered, agreed not to nake a pretectal loo at that tine. Accordingly, Dr. tehee me the only Individual vho epoke co tbe queitlco of lead. Thcee of cur Beebert vho have aa Interval In thle eubject will probably wlab to regtater with tbe,Alr Pol i lution Ccaalaalcn their aupport of tbe arguorote that Dr. tehee advCKed. And, If you agree, ve reccsewad that auch eupjort be provided In writing by you to tbe Ctsetlaalon before february 10. LLA la going to corned favorably to any caae. 3<m nf our aw^>#ra expreeeed an lotereat In a further dUcuetlcn Of tbe Penneylvaale eltuatlan together with tbe atateaent of Pr. tahoe. Accordingly, we are prepared to neet with you for aucb dlacuaalon, If you feel tl la 7. wyiff 'JgRyiwygi.uj'L'1 .mangnE*?-/ i & S LIA11977 r^'oi' litfwi Toi U.O. and Canadian Heeiere of the LXA Health and Safety Cccnlttee January 25, 1967 neceaaary, In Rev York oo the morning of Friday, February Jrd. Will you pleaee let ua know aa aoon ai poeelble whether or not you think a seating la DeceasaryT Vary truly youre. EOF*, aw attachment cci A. 8. Dravaa S. D. Strauaa John Englaborn Julian Bara A. V. Split John F. Rltteshouae R. C. Schaefer Joaejh C. Carter, Jr. Don 0. Fowlar Vllllaa Cairo Kenneth Green Vllllaa Falllea Jaaea Snyder Edvard Adaaa Theodore Ollnore P. C. HucclUt John Keller i >t piympBU P| wapyucpm yis... L#-.^JfLgjgE^gWW^HWHWngfg^WS^f.'g.l!Wr^Pii| ..j^-n^ir-aLKnCT. <^jg' j -.i LIA11978 ( IS 1 Bafor* 2 AIR POLLUTION C0MMI8SI0B CCKMOKVEALTH 07 PEKBSYDrAHIA 3 4 3 PUBLIC HEARD)<3 IH RE: PROPOSED AKBIEH? AD) 6 QUALITY CRITERIA Advance Tranecrlpt of raaarka of ROBERT A. EZHOB, M. D. 7 0 PRES IDIRQ 9 VICTOR H. SUSSKAX, DIRECTOR Division of Air Pollutloa Control 10 11 Stenographic report of bearing be 16 12 at VI11 Ij u i Penn Kuaeua Auditorium, Barrlaburg, Pennsylvania, 13 Thursday, 14 January 19. 1967 at $:y> o'clock a.a. 15 16 17 IS APPIARIW CV7ICIALLYI 19 JOSEPH L. COKER, ESQUIRE Aaalatant Attorney Oeneral 20 Barrlaburg, Pennsylvania Por Air Pollution Commission. 21 HER A. BR0D0VIC2, JR., Chief, 22 Technical Serrlcea Section Division of Air Pollutloa Control 23 Barrlaburg, Pennsylvania 24 25 'so?*:-: M ! ' %%: N 471.01 & V*/ :lc 1 MR. SUSSMAI: z would like to call upon Dr. Hobart 2 A. Kshoe at this time. .. . 3 . DR. ROBERT A. XZHOSt Mr. Suitnan, Members of . 4 tba Pennsylvania organ!ration concerned, Ladles and Gentlemens 5 Kay X say first of all X aa pleased to be bare, 6 and X aa most grateful to you, Mr. Susssan, for nerving ne into 7 this strategic point at this time because of the problems of 8 transportation. 9 X an Robert A. Eehoe representing here the 10 Kettering Laboratory, College of Medicine of the University of 11 Cincinnati. Despite the fact I have recently retired from, the 12 Directorship of that laboratory, X still represent It In 13 connection with work of which X shall speak today. 14 X an here because we have been engaged In the past 15 five years or more In an investigation that Is conesrned 16 specifically with establishment of a proposed criteria, for 17 setting some standard for the concentration that Is In the 18 ataosphere which Is tolerable in conjunction with the lead 19 which Is taken into the body frocs other sources In cur 20 environment, particularly in food and drink. The wo&>vlth 21 which we are concerned has been going on for a such longer l22jporlod of tine but more lately, something like five years ago 2) concentrated on this point as being one which seeaed necessary 24 to settle at the earliest possible tine. The work concerned 25 tiers hat been supported.,by the Kettering Laboratory, has bean / jr: z-z' i Itisl i VWMBSBWWUWa'!' mmi i. i iiiiiwf^iii im" 1 1 upported by thr private Industries and tha United states 2 Public Health Service and various grants. 3 The reason I as here Is to present this 4 lnforaatloo, for what It Is worth, to the Coealaslon, to the 5 agencies of govsrnaent concerned> and also for another 6 reason, which Is that soae figures which Z have provided In 7 public teatlnooy In Washington have been made the basis for 8 a calculation which Z an bound to be concerned with, because 9 there Is one feature of this which Z will Indicate a little 10 later, which has not entered into that calculation, and, which 11 Z nay say It has not been possible until quite recently to 12 Introduce Into that calculation a quantitative basis. I will 13 explain that later. 14 The extent of the work In which we have been 15 engaged, which Is not unknown to nany of the people In this 16 audience, has had as its purpose for the period of the last 50 17 years the understanding of the behavior of lead In the huaan 18 body. 7or the past acaething like 25 years, this hss baan 19 concerned with the base In the huaan body of lead Inhaled froa 20 the ataosphere and what occurs to that In the whole physio 21 logical trend. Aa Z say, this was just soae faw yaara ago. 22 Thsrs are nany probleas concerned with this which began to 23 point ltsalf directly toward the problem of the tolerable 24 concentration of lead in the aablent ataosphere. The reasons 23 for such obssrvatlona, Z think, hava baan apparent. You i-A\ iSSU jbtiaii 1 people in the field of Industrial health particularly and 2 public health aa wall hava known of this for quit# sons time. 2 Row, to gat to the point Z particularly wish to 4 develop la the discussion of what is the basis of appropriate 5 consideration to the problea of tolerable concentration In the 6 aablent air. let se say what we have been doing. Tor this 7 period of tine we have been studying hunan subjects under 8 known conditions of exposure to the lead In the atnoaphere, 9 and since this la impossible without an lnadalsslble expenditure 10 of funds and provisions for experiment, for equlpeent,' It la 11 Impossible to carry cut these observations continuously, that 12 is 24 hours a day, seven days a week on human subjects^ we 13 therefore have to resort to a procedure which has been tested 14 and proven to be valid, aalnly that of increasing the period 15 of exposure to a particular concentration In a Banner which Z 16 shall illustrate. For exasq>le, from three hours every other 17 day to six hours every other day to nine hours every other 18 day to twelve hours every other day and then extrapolate from 19 this which has been deaonatrated to be feasible as to what i 20 will be the situation 24 hours a day seven days a week. X 21 cannot go into the deaonstratlon of literature in theoretical 22 consideration, but soae of the work has been published and 23 available in the literature and will be nade available to 24 those concerned. 25 Our experlaenta in thla field are deteralned to 1 find out tha point -At which the addition of Xaad to tha 2 atmosphere at it now is, undar condition* in which tha intake 3 of laad in food and beverage, maintained at a substantially 4 constant laval, to determine tha quantity of laad that can ha >.3F 5 addtd to tha ataoaphara without going hayond a particulate 6 accuaulatlon that is hamful. Tha point bara is that exposure /, 7 to laad in tha aslant ataoaphara daapita aoaa dagraa of 8 availability in concentration is a continuous process, and 9 It has haan clearly demonstrated by cur previous work that r 10 whan tha individual is exposed to a sufficient lavsl of intake 11 of laad at increased levels, the concentration of lead in the 12 urine, tha concentration of lead in tha blood and eoncentratloi I 13 of laad in tha body proceeds at a rata which is Catsruined by <r 14 tha sisa of tha doss ani continues indefinitely at that rate & r. 15 and presuaably continues at that rata throughout a life tin*. I 16 V* have followed experiments in subjects for as long as five 17 years and have found no abatement in this rat* of Increase in 18 tha body, and therefor* it is apparent that the safety of tha 19 individual froa the point of view of tha inhalation of, laad, 20 on top of what is taken in in food and drink, its safety is h 21 having a doe* froa day to day that doe* not result in a 22 progressive accuaulatlon in the body. On the basis of this, 2) our experiment! hav* dealt with 10 alcrograa* of lead in the 24 sab lent stoosphere, and the experiment* Just concluded and 25 not yet published had demonstrated that at this level, within . . mm te*f iWMt 'i.*'**+, : ' hV i~ 'i v-a * 'IV4 1 the Halts with which ws can proceed, there is no rssponss on 2 tbs part of tbs individual in terns of tn increase in the 3 level of lead concentration and output in urine, no increase 4 in the concentration of lead in tbs blood and ergot no lncreas< 5 in the progressive acemulation of lead in the body. Wbat we 6 have done then is tabs the next step and go to 20 mlcrograjoa, S and this experiment has been underway since October of this 8 past year. 9 The ultlasts goal of these experiments Is to 10 determine in terns of the behavior of the human subjects the n degree of effect produced by a given concentration of lead in 12 the air. As I say, the criterion for safety in physiologic 13 terns would be the adequate handling of certain quantities of 14 lead which would not result in progressive accumulation In the 15 course of s lifetime in s healthy individual. 16 The experiment has not been completed. It will 17 not be completed for et leeet another year end e half, and it IS would be impossible for me before that time to state the result 19 of experiments. The result cannot bs anticipated because there 20 is no information on which to drew. 21 This brings me to the question, therefore, of a 22 calculation based on our provious evidence not totally 23 complete. In order to save your time and mine and in order to 24 be quite sure that what Z have said here is in no sense of the 25 word overdrawn or ambiguous, Z have chose to write out in MM ->A"V 'o'if v ^ -y V / ,<fM> 1 longhand last night just what Z was going to say on that 2 subject. Z will submit a statement later, but this portion V;u'wv'-* *2`" . -t- * - 3 Z will include. 4 The evidence obtained fron the conduct of balance 5 experiment* on subjects under the controlled conditions 6 of the laboratory, together with'that obtained by randon ' .`V-' .7 sampling within the general population, has demonstrated that 8 the Intel* of lead in the food and beverages of the 'average* 9 adult citizen -- "average" meaning a kind of statistical * 10 aodel nan -- "adult* if Z nay use that expression -- cltlsen 11 of the United States is of the order of 0.30 nilligrea per 12 day. Under present conditions, with reference to the lead 13 content of the food and beverages and of the aablent sT 14 atmosphere, the total dally Intake of lead into the body is 15 balanced, for all practical purposes -- and by "all practical 16 purposes* Z mean within the limits of experimental deviation 17 of the operation, what can be detected -- by the dally output 18 of lead from the body, so that no Masureable quantity of lead 19 accumulates In the body fron year to year. -ik. 20 The safety of the population nay be regarded. i 21 Ideally, as being dependent upon the nalntenance of euch a 22 physiological balance between absorption and excretion 23 throughout the lifetime of the individual cltlsen. The faots 6 24 to be deteralned, therefore, ae the criteria of safety, 25 conelste In the establishsent oft m '1 Jg-V 'J .i 1 'I 1 (1) The upper Unit of tha daily dose of laad 2 that can ha lngeated la food and beverage without resultlag % 3 la a progressive accumulation of load lo tha body, while the 4 respiratory intake Is being held constant. X am talking hare 5 about experimental subjects with which you study one at a time 6 (2) Tha uppar Halt of tha dally dooa of laad 7 that can be Inhaled, with tha ambient air, without Inducing 8 progressiva accumulation, while tha Ingestion of laad In food 9 and beverages Is being held constant. 10 The experimental work on these two factors has 11 deaoostrated, for the first of them,, that when the average^ 12 dally Intake with food and beverages has been doubled over 13 what It is on the average, that Is to say being raised to 14 0.6 milligram, it is Just barely possible to detect a slight 13 increase In the output, or the concentration, of lead In the 16 urine, without any demonstrable increase in the concentration 17 of lead In the blood. Under these conditions, the body 18 burden of lead Is increased by a quantity of the order of 19 8 milligrams in the course cf one year. This has to be 8 20 milligrams plus or minus some factor that represents 21 deviation of the operation Itself. It is In that order of 22 magnitude. 23 The experimental work underway on the concentratloii 24 of lead in the atmosphere, as X said a moment ago, breathed 23 by human subjects, is required to yield a similar result has *** , **** ***** ****** ********* m v*. Hvv-'i*. -- ' '.t- i 1 not been completed. The inhalation of elr containing 10 2 mlcrograma per cubic meter, the eeaquloxlde dleperaed In 3 pertlclea of the nean diameter of 0.05 micron haa failed to 4 yield any evidence of an lncreaae in the abaorptlon of lead* 5 The next atep in the experimental program haa 6 been taken, therefore, by raising the concentration of lead 7 in the air breathed by human subjects to 20 micrograaa per 8 cubic meter. This experiment was initiated In October of 1966, 9 and it ia expected to continue for 140 weeks unless definitive 10 results are obtained at an earlier time. Vothlng of slgnlfl* 11 cance has been learned therefrom thus far. That la to say the 12 observations are not positive. They have not gone on for a 13 sufficient period of time. 14 The outcoce of this experiment Is unpredictable, 15 quantitatively, since there is no available Information on 16 which to base a Judgment. 17 One of the factors which enters into the 18 uncertainty as to the outcome, is the rate and the extent of 19 the clearance of particulate watered that is retained In the 20 respiratory tree during the respiratory cycle. That^ft 21 breathing In and broathlng out. One breathes in a certain 22 quantity of concentration that is ia the atmosphere and one 23 exhales air containing concentrations, and the amount that la 24 retained in the respiratory tree la the amount of difference 25 between the two. The amount of air retained la not negligible I -* ' -i- t.V-K ^ 'C ' \ ' r * ' \r `` -\{. ' -\-' - * - *'*'" -* - . * v , 1 - . . j* f * ''ki jT 0 3 i? ' >* 10 , 1 but It ! not so largo as to exclude reasonable Judgment. 2 Recent evidence asseabled by a task group of 3 experts on lung dynamics, for Cooaittee IX of ths Internationa: 4 Ccoalsslon on Radiological Protection (Health Physics Pergaaon 5 Press 1966 Volume 12, Pages 173*207) indicates that the near 6 aeasures*nt of the deposition of lead in the respiratory 7 apparatus during the respiratory cycle, by subtracting that 8 which is exhaled fron that which is inhaled. It seeas to ae, . 9 falls far short of the total quantity cleared .froa the lung. 10 Other nechanlsas of clearance, extrusion fron the air sacs, 11 and movement of particulate aaterial in aucous, upward to 12 the naso-pharynx and ultimately into the aliaentary tract by 13 aans of cellary action, are said to reaove all but about 10 14 per cent froa the respiratory systea. This evidence, based 15 In part on calculations froa theoretical considerations, and 16 in part frca the respiratory model that has been set up by 17 the experts in this field, provide an explanation of the 18 difference between our observed results and those which would 19 have been anticipated had all of the lead retained during the 20 respiratory cycle been absorbed, & 21 X ssy here parenthetically that inasmuch as we 22 have known that a given quantity of lead in the atmosphere doei 23 not produce the kind of response In terms of exoretlona, as 24 In concentrations of the blood that it should, thsre is a 25 difference here between what is observed and what could be MM |(H r*it -C-J (- ` .y V- li5 V` ' ` ` -3* *r~^\r-r v> y *** 'tA'i*-'* f >"-* >/ ' : **- -` &* 'y#?gr*rVpy*"*>,*a'*5<? Zi"'"'!. S'* * V^v,,njwva/rwJ^EeJt',>rtr 11 \*5 . 1 Anticipated. It has been lnpoaslble up to the pretent tlae 2 to put numbers on thle difference. In consequence, since It 3 lacked any quantitative expression, vs have not been In the 4 habit of undertaking to try to guess at It or to coee to any 5 conclusion. But recently, in connection with the activities v V* f- - . " 6 of this International Coaaittee, based on the observations of 7 radioactive Baterial and Its behavior in the pulmonary tree, 8 and a number of other factors, only recently have they been 9 willing to stick out their necks, so to speak and put nuabers 10 on that process, and the estlasts that Is Bade here is the 11 best estimate that can be aade by the experts In thle. 12 I night cite here all of us know who Is working 13 on this In this area and know hla as being one of the aost 14 reliable and precise workers In this field. That gentleaan 15 Is Xr. Ted Batch froa Pittsburgh, a eeaber of this Internatlon 16 al Coaaittee. It Just happens I have known this gentleaan 17 long enough and recognised this source long enough that X 15 have complete faith in bis Judgaent, and X know aany of sty 19 colleagues would. This Information has been avallab^only *s-> / - 20 quite recently to ae, and this is, therefore, the first tlae 21 that Z have ever undertaken to put nuabers on this particular 22 aequance. I did refer, In an earlier discussion, to the fact 23 that It did appear that only something like 20 per cent of 24 the materiel that is deposited In the lung appeared to be J valid 25 absorbed. This Is froa our^experlaents. lees ** ****** TO"! LIA11989 '':V.v JL2_ ? e% 1 At present on the basis of our sxperlmental 2 results and the foregoing Interpretation of physiological 3 mechanisms, it la reasonable to conclude that approximately 4 10 per cent of the lead In the air. In the fona represented / 5 In our experiments, la available for absorption. This fora ` 6 la not remarkably different from that which is found In the 7 ambient atmosphere after the settling out of the coarse 8 particles. Accordingly, the best statement of the probability 9 of the absorption of the lead frco the atmosphere by the 10 average citizen of the United States, that could be cade, at 11 present, after making the necessary correction in the 12 calculation that has led to the suggested tolerable level of 13 5 mlcrograms per cubic meter would be the following, and fro* 14 here on X am simply taking the attempt of the Commission and 15 the advisors in making calculations froa our own data. X am 16 simply undertaking to put In the new figure of what can ba 17 expected to be absorbed ea a basis for e new calculation. X 18 have not dared to say this Is a correct figure, because as X 19 shall mention latar this Is yst to be determined experiment 20 ally, but this would be the best guesstimate that X could put 21 o* this matter at tho present time. 22 Accordingly, the best figure that could be arrived 23 at, for the tolerable level of lead In the atmosphere. If one 24 were to employ the method that yielded the figure of $ micro25 grams per cubic meter, as taken from my testimony befora the 13 1 Kuskle Committee, would b of the order of 18 micrograms. 2 Thl* figure le obtained by eubstltutlng 10 per cent of the 3 load retained In the respiratory apparatue during the 4 respiratory cycle* for the 50 per cent used in that calculating, 5 and then asking allowance for the absorption of 10 per cent 6 additionally of the quantity which le removed from the 7 respiratory Into the alimentary tract. This we believe Is 8 the nearest approximation that could be Bade at this tine. 9 The teat of the correctness of this estimate will be provided 10 ultimately by the completion of the experimental program'/ n designed to establish the actual facte. 12 There le only one additional comment that Z would 13 like to make at this time which X think Is highly pertinent 14 to this problem, and It Is one which X think all of us who 15 have been working responsively in this field have had to take 16 Into account i namely, that If, as we will have done eventually 17 one can set a concentration of lead in the air, which, under 18 present conditions, with referehoe to food and drink, would be 19 a safe and tolerable concentration for a norail, h|althy adult P 20 what should be the criteria that should apply. X hope X am 21 not oonfuslng criteria as establishing what should be the 22 criteria. Vhat should apply to the total population, 23 represented as It is, by the very young and the very old. 24 X have only one comment to sake on this, a rather 25 Important comment that is the result of soae 30 years of t * rM* I - i -mj * 1 observation in this particular field which has covered both 2 experimental work in the laboratory and a good deal of 3 clinical* practical work in industrial hygiene. 4 There waa a tine a number of years ago that Z 5 think all of ue believed that the susceptibility of lndlvldualn 6 to certain things was a highly variable thing. This arose out 7 of observations of a variety of persons in the general 8 population frca tine to time developing lead poisoning under 9 clrcunstances in which it is Impossible to determine the 10 extent of their absorption. It was our cuatoa* as it is sd e 11 easy the custoa In many places* to say* "Veil* these are 12 unusual circumstances and that person had unusual suscept 13 ibility." By the seme token* in industrial environment* we 14 have seen the occurrence from time to time of a case of lead 15 poisoning where we had thought this case should not occur* 16 and we have said* "This is an unusual situation. That must 17 certainly be due to unusual susceptibility." JlSt 18 Z am here to tell you* gentlemen* that as you 19 observed these situations* and as each kind of thli^pops up 20 and has popped up consistently over the period of the last 30 r 21 years* since vs have now been enabled by appropriate methods 22 to measure the degree of absorption* vtut wa have found la not 23 thet thle Individual Is unuaually susceptible but that hie 24 bshavlor In his environment* in hia occupation* haa been auch ' /(J ij.yS 25 that he hat absorbed such more lead then was good for him end is . *% * teas e*f fMest -- MwH 13 T 1 ouch nore lead than people who were living next to hi* and 2 tide by aide. Ve have had so nany sxasples of this that it 3 has led to a degree of skeptic in concerning this notion, 4 skepticism which is sore Justified by this fact: Ve have 5 never seen a bunaa being, young or old, recently born infant, 6 or men in the nineties who has developed lead poisoning, 7 except as he has had at least a level of concentration in 8 the blood which indicates clearly the order and magnitude of 9 his absorption. To be specific, we have never seen a case 10 of lead poisoning in a child or adult unless there has' been 11 at the onset of the illness at least 80 alcrograas in the bloo 12 This is not a level which means illness, this is the lowest 13 level which is coincident with the danger of the occurrence 14 of lead poisoning, in consequence of which, we have been 15 ccopelled by our observations, as have nsmy other clinicians 16 in this field, to conclude that a very considerable quantity 17 of our notions concerning undue susceptibility were the 16 result of precise observations over a period of years. This 19 is not to say that there is not a variation of susijiptlblllty. 20 The variations of susceptibility occur, however, at a level 21 of absorption which has no relationship to the current 22 absorption to lead in the general population. This is why Z 23 would say that as one night be perfectly willing and reason 24 able to back off Just a little bit from a figure that would 25 represent what is safe for normal healthy young adults, we i g SISMH. ** . MM HSH I---- -j '1 <9 1 might back off a little bit from thla, but wo have very, very 2 little Justification of tbo old wlveo tale for backing off 3 Tory far. Thank you vary much. 4 XR. 8USSXAI: Dr. Keboe, wo bavo ona or two . 5 qua*tIona. Z would liko to bo auro of a fow of thoao things 6 you aald. first, In our calculation wo uaod 50 par cant 7 availability factor for abaorptlco and you recommend 10 par 8 cant -- 9 DR. ROBERT A. KEBCEj Toa. 10 XR. SUSSXAJ: -- now, la thla baaod on occupatlooa . 11 experience, oxpoauro or roaaarch with animals or what la tho 12 baala of tho 10 percent? 13 DR. ROBERT A. KEROS Let ua bagIn with tho 50 14 par cant. In our observation co buaan subjects under tbo 15 conditions of breathing air containing that of a certain 16 quantity under laboratory conditions, wo have found that tho 17 particles, something of tbo order of magnitude which Z spoke, 18 tbo Man disaster of .05 alcron, which la very close to tho 19 maximum, to tho Ideal state, that froa 35 to 50 per cant -20 not Just a flat 50 but fron 35 to 50 per cent -- of tho lead 21 that la taken In In the respiration la breathed out 22 Immediately In thla successful exhlllrstor. Thla means that 23 much that la trapped In tho respiratory apparatus, something 24 of the order of 35 to 50 per cent, shows a retention. Row, 25 what wo bavo known from our experiments over a period of yaara L : ,* sV ; -v ' ft; > ' -l 9 -i < :i ________________________________17 1 la that tha response of tha Individual doaa not rtally 2 correspond to tha absorption of thia 35 to 30 par cant -- It 3 la always considerably lowar -- and Z bava navor previously, 4 and In nona of our published work bava Z nada any calculation 3 which enables us to predict what has bean tha degree of 6 absorption, what has bean tha degree of accumulation, for tha 7 simple reason Z have not known what this factor la, what this 8 obvious error of observation was due to. In consequence, in 9 ay writings, and It Is ay testimony, and in ay testlnony with 10 tha Kuakla Consulttee, I aade no reference to tha fact that^ , 11 there la a difference of this kind but slaply said, "What 12 occurs here is the retention in the body of 35 to 50 P*r teat 13 of that which Is Inhaled.* I s la?ly left It frees there bee sue i 14 we have not any neane of getting the extent of this thing. 19 As it happened, a group of people with ay knowledge, had 16 been benefited by tha fact they can follow radloaotlvs eaterlaL 17 through tha respiratory tract have bean working for quite 18 sccte tine on the creation of a standard for tha Inhalation 19 of tha radioactive aaterlal, and they have now coosyout with i 20 this published aaterlal to the report of this Cooalttee for 21 tha first ties putting numbers, which you srs at liberty to 22 disregard, feeling they heve a degree of error In thea, aa 23 Z aa, because Z aa not quit# sura that they art right. All Z 24 can aay la this Is tha aost expert group aa far aa Z know In 25 tha world In dealing with this problea and this la their ---- i i sweaite * asssw a h m *h *i |*a-- . siss >ig M ............... im|i|'.s-^^;5a.suiji^ miAM ji.il ij ^h ! -J-.JJJ-'Ji g! 3 5 .<jyt ^ .:^S.tawiri!JV*.. 18 1 interpretation. In consequent, end this Z ea quite 2 prepared to say, other mechanism of the lung, in the 3 extrusion of lead frca the ambient air, by whatever method 4 this does occur If It does occur, plus the muclnold 5 excretion of ciliary action, which carries this out of the 6 respiratory tract up to the naso-pharynx, at which point most 7 of it is swallowed, has for the first time put numbers on 8 them. Ve would tender, a year and a half from now, with 9 reference to the kind of particles we are dealing with, - \ y 10 whether these numbers appear to be correct. I have no, ; 11 choice at the present time but to accept them as the best 12 evidence we have. 13 XR. SUGSXAJ3: vith reference to what you are 14 doing now, you stated that 10 microgram per cubic meter 13 shows no adverse effect with respect to the application of 16 lead. 17 DR. ROBERT A. KEBOE: Xo physiological effect 18 at all. Vhat that means is this: The quantity of lead taken 19 into the alimentary traot amounting to about 0.30 Milligram r 20 per day -- this is a variation up or down -- In which It from 21 time to time goes up to as high as 0.3, O.JO, 0.60 or higher, 22 almost every time this occurs, thore is a period in which 23 there Is an Increased Intake for any one of a thousand 24 reasona, such as the Individual's choice of diet, cepending 23 on what he hea been drinking and eating and so forth, every Me* ** > msgs gmymjjj V w> y*tnac TO- -u'W** .1 _*! .^.a a-*<!<61'^.' 1 aWarfr 19 , tlaa this goes up, the concentration In the urine goee up. Vhet I aa e&ying it wo have not been able to put our finger on any increase at all which la referable to the experimental thing, that la within the variability of our test nothod of procedure. HR. SUSSXAH: Do you believe there la any difference between tho type of lead to which they are expoaed' and the levala that are found in the body; for example, a difference between aay the organic or inorganic type of leadf DR, ROBERT A. KI203: Vlth respect to the factor of absorption froa the lung, there la undoubtedly a factor concerned vlth the solubility of the aaterlal, correct. For example, we have reason to believe clinically, without having very good scientific evldonce of the fact that the information on lead sulfide ccaos very close to being innocuous because it is disposed of es an insoluble Inert material, and by reaeon of the feet has e treaendous influence on the hazards associated with lead In the ataosphore. If the particles are large, they will be strained out in the upper allaentary tract, and if they ere sufficiently aaall they go into the air sacs, in the deep alveolar duct* where the surface is enormous and the opportunity is great for absorption. There is s very considerable difference in the nature of tbs coapound and the else of the particles. It so heppens the lead which la in the atmosphere, the very lmrge proportion J LIA11997 i * **aMg.WrilW'j -- n*^ --Tlj>iVitar>r*v' ^'mV* .-fciMririifii 20 of this, la that which la In tha order of magnitude from 2 about one micron down In size. That la a large proportion. 3 Consequently, this la respirable lead, and some of this we 4 will get into the alveolar ducts. That la the worst situatico 5 that we can be faced with In terms of size of particles and 6 the nature of the compounds, and we can set the criteria on 7 this basis, being sure there are other safety factors. 8 KR. SOSSXAK: Hr. Kehoe, In your studies you are 9 exposing "normal healthy average type people to -- 10 DR. ROBERT A. KEHOE: As good ss we can find. 11 HR. SUSSXAH: -- to concentrations of lead In 12 clean air. Is it possible that contaminated air, air 13 contaminated with sulfur dioxide could Impair the ability 14 of a lung through ciliary mechanism to get rid of lead so 13 that sore might be absorbed In a dirty atmosphere than in 16 clean atmosphere, and also by different types of subjects, 17 people with emphysema, people with respiratory diseases, 18 anthro-slllcoels and so forth? 19 DR. ROBERT A. KEHOE: let's say, first of all, 20 with reference to the presence of gas -- Z think there is 21 very little question you are dealing here with gas In 22 sufficiently high concentretlon, and Z am not prepared at 23 this point to say what this concentration should be la 241 rtlAtlon to ciliary action. Z just don't know. But, Z may 23] be mistaken about that too. If the effect of the gaseous -------------------m----------------- il<^aBBM!PgtJSm!l AtWiWIUWMUiPi. aHWUMeM-.OTI SmWWS. ... WIUIM LIA11998 7J -*I s -^-iiiii^ti'-^n---- - i*i* > r--.<lLi*i&+&.AZ 21 1 material in the contaminated air Is sufficiently groat to 2 Interfere with ciliary action, Z havo not any doubt that tho 3 lung clearanca under this condition would bo relatively poor 4 With reference to respiratory disease, the one 5 thing that seems to as a safety factor of ecae importance In 6 this situation la that the Individual who la sufficiently 7 creatod a respiratory cripple la going to confine his physical 8 activities to the point of having relatively low intake of 9 air In the lungs. If this Individual la enough of a cripple, 10 he la going to spend a great deal of his time Indoors where 11 the concentration la going to be appreciably lover than In 12 the outside asblent air. You can say these natters are a 13 little bit obstruse. So they are. The whole basis of our 14 argument la the difference between normal and abnormal, and 15 also at this point is by no swans, from the laboratory, based 16 on valid factual infomatlon. 17 XR. SVSSKAXt. I have Just c u m or two sore 18 questions. Z do not knew whether you want to auke an 19 assumption, but assuming that the studies you are conducting 20 new with 20 mlcrograae per cubic meter Indicate a build-up 21 In the body, If that were to occur, what would be a practical 22 criteria for lead in the atmosphere If it were 20 mlcrograms 23 in laboratory experlaentsf 24 DR. ROBERT A. KKiOZi Let me say this, from the 25 point of view of experimentation, this Is the best thing that i MH , " ;v> p A-i-- LIA11999 iI -i f-jr* i ~'ihrw-tr^'Vf' ',"'V~-J`e* 22 -'- w 1 could happen to terminate those rather expensive operations. 2 The best thing that could happen, with thd 20 micrografts we 3 could find at scx&e level of tine there is a slight deviation 4 froa the normal and this would build up with increased aaounts 5 of tine to a point froa which we could extrapolate with the 6 result such as we have in the case of the such easier Job of 7 determining this situation in the alimentary tract. At this 8 point I would say we had to back off soaewhere between this 9 figure of 20 and the figure of 10 which is innocent of any 10 such thing. % 11 12 HR. 8VSSMAS: That is in clean air and -- DR. ROBERT A. KEHOE; Vhere you back Off is 13 dependent on your Judgment. 14 KR. SUSSKAH: -- and that would be for your subject 15 group your figure of 10 and 20. I ea talking about the $ 16 coaaunlty level. Would you directly apply the ember you \ 17 get to the coaaunlty level? \ 18 y DR, ROBERT A. KEHOE: Z think you could probably i 19 do this. I alght be a little cautious. You oay be less or 20 store cautious than I, depending on judgment and experience. i 21 Vhat Z would be inclined to feel Is what happens to our 22 subjects under the conditions of laboratory conditions, which * 'i 23 la of no variation In a concentration, In which we are dealing 24 with a compound of known characteristics and known set of 25 deviation, that we have a vary considerable built-in severity -''- - v***"*^- J-t.. j i Vs'i iiii^"h^tWiriiwTliiia^At,~-'r--~ rf>v-,T-'ri^ womapqewiwpWl^psmWWglPfeieswy'T^ _ . ;. -;:t?&/A ,- '' $5*iw "** ?**K, ^0 ` togui': A k&a 1 i -T JL 1 vhlch would give the number that cocos out of this the 2 built-in safety factor. I would bo protty nearly willing to 3 accept this. Z would be Quite willing to accept this because 4 of the results obtained in the study of lead in the atmosphere 3 In relation to the industry. When we have Investigated the 6 effects on the human subjocts of laboratory exposure to 150 7 micrograms within the Unit of the Industrial cycle, we have 8 found that the highest level in the blood that we get to is 9 in the order of 0.042. This is so far short of the question 10 of danger that I just know perfectly well that our situation 11 that we are studying in the laboratory is very, very much 12 safer than the average conditions that exist in industry. Z 13 aa pretty well convinced this is pretty good. X would not 14 stick out my opinion in this despite the fact X think it is 15 worth a good deal on the basis of our experience. X wouldn't 16 put my judgment in this matter in very strong opposition with 17 the judgment of other people who have put in a little bigger 18 safety factor just to be sure. 19 KR, 8US8MAX1 Thank you. Dr. Kehoe. 20 Are there any further comments on the lead 21 criteria? 22 (Ko audible response.) 23 XX. SUSSMAXi If there are no further comments cm 24 the lead criteria we will go on to the next subjeet. 23 CM . IMS 9MH >--at msee ihN at