Document pBJqvEgw6R1xbRzzvwjKqNQ6B

9036 Jeffery Road Great Falls, Va. 22066 April 12, 1977 ' Mr. Joseph Padgett U.3. Environmental Protection Agency Office of Air Quality Planning and Standards MD-12 Research Triangle Park, North Carolina 27711 ^ Dear Mr. Padgett: I have been asked to also send you the en closed statement concerning my analyses of Dr. Robert A. Kehoe's lead balance studies in humans, which I recently sent to Mr. James Smith of the Criteria of Special Studies Office of EPA at Triangle Park,. Please direct any questions you have to me at my address as indicated. Sincerely yours, Stanley B. Gross, Ph.D. (703/759-9311) cc: ''Dr. Robert A. Kehoe Dr. Gary Ter Haar Mr. James Smith enclosure 9036 Jeffery Road Great Falls, Va. 22066 April 11, 1977 Mr. James R. Smith Criteria of Special Studies Office Health Effects Research Lab MD-52 Environmental Protection Agency Triangle Park, North Carolina 27711 . Dear Mr. Smith! ^ I have been asked to send to you the enclosed statement concerning my analyses of Dr. Robert A. Kehoe's lead balance studies in humans. This data should be useful to the Environmental Protection Agency's con- . sidrations in setting the National Ambient Air Quality Standard for Lead. Sincerely yours, Dr. Robert A. Kehoe cc! Dr. Gary Ter Haar enclosure Stanley B. .Gross, Ph.D. (703/759-9311) f ' .1 STATEMENT relating to the National Ambient Air Quality Standard for Lead April 11, 1977 by Stanley B. Gross, Ph.D. 9036 Jeffery Road Great Falls, Virginia 22066 presented to Criteria of Special Studies Office Health Effects Research Laboratory MD-52 Environmental Protection Agency Triangle. Park, North Carolina 27711 ' I am representing Dr. Robert A. Kehoe of the Department of Environmental Health of the University of Cincinnati and the Ethyl Corporation of Baton Rouge, Louisiana. I am a toxicologist and I have been completing the data processing on Dr. K e h o e 1s lead balance studies in human subjects. Dr. Kehoe began these experiments in a 193^ and continued them until 1972. Sixteen individuals were studied under normal conditions and under conditions of lead supplementation in their diets or in the air they were breathing, for a total of more than 21, 000 days of measured exposure to lead. A considerable amount of Dr. Kehoe's data have already been published; however, the data from several of his experiments have not. fty task over the past two and a half years has been to compile the bulk of Dr. Kehoe's data for the purpose of my own analysis and to publish the data from those experiments which have not 0000456 f pg 2. statement by Dr. Gross, 4/11/77 yet been published. In contrast to Dr. Kehoe's previous reports, I have applied computer techniques to present the data and to analyze them statistically. I am currently working on a monograph which will contain the results of my analyses. The monograph should be completed in the next three months. When it is completed, a summary of my findings will be submitted for publication in one of the scientific journals. Part of my findings has already been presented at the 1975 Annual Meeting of the Society of Toxicology '^ in Atlanta. The purpose of this statement is to present a very brief summary of some of the results of my work on Dr. Kehoe's data as they pertain to SPA's concerns in setting a National Ambient Air Quality Standard for Lead. A copy of the computer tape containing the data can be made available to EPA for the cost of duplicating the tape. Methods. All of the subjects were followed through out these experiments by a physician other than Dr. Kehoe by periodic histories, physical examinations and laboratory studies including hematology, urinalyses and chemical analyses of their blood and urine in order to insure that each subject experienced no harmful effects due to their experimental exposures. There were a total KE 0000457 Pg 3L. statement by Dr. Gross, b/ l l / 77 of 102 periods of study for the 16 subjects, Through- out all of these periods, each subject collected daily samples of his or her diet, feces and urine which were analyzed for lead. Blood samples were obtained on an approximate weekly basis and were also analyzed for lead. Each subject was initially observed during a control period (ranging up to 602 days) in order to obtain baseline data on the subject's natural exposure to lead. The control periods, in the case of the inhalation experiments, were followed wi-m one or more periods during which time "the subjectTworked in Is' 5/ special inhalation chamber|' equipped with/devices for generating and monitoring aerosols of lead. The in dividuals remained in these chambers for periods of A. 2 to 13 hours per day, from every other day to 6 days " 1/ per week, in periods (ranging 1to 772 days). The r&hamber (r'fjlnii Viduj auk ' concentrations ranged from 10 to 150 micrograms erea=d / per cubic meter, corresponding to 2 b hour adjusted exposure rates of 0.6 to 359 micrograms of lead per cubic meter. The lead aerosols in the chamber had median count diameters of 0.11 to 1.20 m i c r o m e t ^ s ^ j The periods _. f- y, , , ij \ of exposures were followed by post-fexposure psfcikMis,' u ) U coat.tf . A ^ A' ^exceptqin .one subject fealhg.ng^upgs^os^g^^ay^), d w n g 'A 0000458KE pg statement by Dr. Gross, k/ll/77 3umma ry !Findings. It should be emphasized that i M B ^ (Ltpbjt^uiA ^ , none of t h ^ t ^ ^ ^ s ^ ^ o n f g u t g ^ s t^icperienced any harmful / '-cvk N' > i effects*dqe=fee~-their-e-xpos-u-reS-. The highest -adjusted, _ -^pssxffiB^-garte-s- were . approximately 30 micrograms per, 1f(A I) 'Zi 'f cubic meter.,'for periods o,,.fp n36.kiti$3E&? 6l6 days ^ 7\ ject r '"Jtj 628 days. /n lsubject MOB.' 330 days, ##* 'sub ject MB} ana -rate -appreieiffiarteiyy36 ^micrograms of lead \ per cubic meter of 112 days . lie, subject LD. In nerre 'Tof~th^e_sxib^errts did the mean blood lead concentrations 1 exceed ^0 micrograms per deciliter, except ^or one^ subject JOS^whose highes't" m--e^n_-^fba-l-oo,d I,'xl-e"adA^-w-a-s ^-^jnicroj Agrams per deciliter. i 4} iil /T~U.ty.aJi Thei.e)-uEifie-^e^Eis/in resppconse to 'ViLz. expo sur e| ^dief not exceedT^T mean^ of .my 86 micrograms per day. -Tubero--wars fG r c o n sid e r b le s it%MsJjtM, the blood and tr , , ;; of variation in^Cm<PCui7\ jS d>M) the ~Pf J f 9 h M 'M A M experimental periods which were apparently in response to spontaneous changes of the subject's dietary lead Jle3es. This phenomena tended to obscure the dose- response effects seen in the blood and urine of th lower levels of exposure, Th u s i n a d ju s t e d ' / *"? \ 7 > up t o 20 m icr o gr am s of" l e a d p e r (ieubic m e t e r J t h e ci^ cuj^ UA _u( Cb> Ix-^Zi ^ t e n ge s^ in ) b^Lood an d u r i h ^ v ^ l^ad-% eaal^ - asass. c o r r e l a t e d L - ' '-- i VH,'' -Mtt ' only with changes in^dietary lead. It was not until the ^ Vl iZ j^ ih Z d J adjusted c o n c e n t r a t i o n s e x c e e d e d 70 micrograms of lead pg 5 statement by Dr. Gross, ty/ll/77 per/cubic meter!that the blood and urine reJ^tee-^feed- the increases in airborne exposures. By means of visual estimates of linear regression lines throughout the data points, the increases in blood, urine, and feces were O .38 micrograms per 100 grams, 0.88 micrograms and 2.50 micrograms per day, respectively, for each micro gram per cubic meter increase in airborne lead. ___ It was also interesting to note .that mean b l o o d rlead concentrations UL jects tended to decrease statistically throughout the Ayears of these experiments (193^-1970). This decrease in blood lead concentration was (statisticall y associaj;ed/-j\ ' ZT It 'f'JL&'jthitt; with a decrease in dietary lead .but may also, haver responded / /A. to the decreases in the amount of lead in the Cincinnati n air observed by others. / Qftcfe.