Document XR5O7j9NZ4y9VzyqZ42rGaYRG

COPY A p ril 7 , 1938 Mr* P* A. Combelic Wash in g t on St a t a A g r ic u ltu r e Asa *n * Spray R esidua Committee Dear S iri Your l e t t e r of March 23rd r a i s e s a q u e s tio n t o w hich, in my o p in io n , th e r e 1s no an sw e r. The problem o f sp ray r e s i d u e s on f r u i t an d , more p a r t i c u l a r l y , on l e a f y g re e n v e g e ta b le s i s an Im p o rtan t problem in p u b lic h e a l t h . Much h as been w ritte n on both s id e s of t h i s q u e s tio n b u t , u n f o r tu n a te ly , n o t much e x p e rim e n ta l work ha3 been done to j u s t i f y a 3ound op in io n as to the f a c t s . I p e rs o n a lly do n o t f e e l th a t the p o s itio n o f th e a la r m is ts i s w e ll ta k e n . On the o th e r hand I do n o t f e e l th a t th e re is any a v a ila b le evidence which would j u s t i f y the Bureau o f Pure Pood and Drugs in th e D epartm ent of A g ric u ltu re in r a is i n g th ese to le ra n c e s f o r e i t h e r le a d or a rse n ic * The to le r a n c e s , as th e y now e x i s t , have no v e ry sound s c i e n t i f i c o r p h y s io lo g ic b ac k g ro u n d . On th e o th e r hand I f e e l t h a t i f t h i s Bureau i s to be i n e r r o r , i t sh o u ld e r r on th e s id e o f s a f e t y . Moreover, w ith a l l due re sp e c t to Dr. I r a C a rd iff, w ith whom I h av e t a l k e d , I do n o t b e lie v e t h a t b is p o s itio n i s w ell ta k e n when he say s t h a t i t is up to t h i s g overnm ental agency to prove the co rrectn ess o f i t s p o sitio n w ith regard to le a d and a r s e n ic t o le r a n c e s . I t 13 r a t h e r up to th e in d u stry to prove th a t the to le ra n c e s -estab lish ed by th is d ep a rtm en t a re i n c o r r e c t . As a m a tte r of f a c t th e s e to le ra n ce s are s e t by the Departm ent a f te r c o n su lta tio n w ith q u ite a number o f men who a r e presum ed to be a u t h o r i t i e s in t h e i r f i e l d * These men e x p re ss th e combined judgm ent o f e x p e rim e n ta l w o rk ers who know t h a t b o th le a d and a rse n ic are to x ic substances and .hat th e ir presence in food f o r general consumption should be lim ite d . I p e r s o n a lly d is a g r e e w ith some of th e e x p e rim e n ta l e v id e n c e . on w hich t h e i r c o n c lu s io n s were re a c h e d * However, i n th e s t r i c t s c i e n t i f i c s e n s e , and from th e p o in t o f view of t he y p u b lic h e a lth , th is is u n im portant and/ t were re sp o n sib le f o r the a d m in istra tio n of th is B ureau, I would n o t change th e to le r a n c e s upward e x c e p t on th e b a s i s o f v ery sound evidence th a t they were u nreasonable and u n n ecessary . Moreover w ith e x c e lle n t a c ie n tif ic evidence a t hand as to the le v e l of lead and a rs e n ic in ta k e which could be endured N20256 2 s a fe ty f a s t e r in vie of the f a c t th a t c h ild re n and sic k people have to be thought of in connection w ith g en eral d i e t a r y p ro b lem s, VJhat I have s a id above would seem to in d ic a te th a t I la c k sympathy fo r the fru it-g ro w in g in d u s try This is not the c a se , I reco g n ise the d i f f i c u l t i e s of t h e i r s i t u a t i o n * and I am s tr o n g ly sy m p a th e tic w ith t h e i r problem when I r e a l i s e t h a t th ey must In a measure choose between a lo ss of th e ir f r u i t because of In se c ts and daage to t h e i r f r u i t by v a rio u s ty p e s of w ashing o p e ra tio n * On th e o th erh an d i t sh o u ld not be necessary for the ordinary c itiz e n to have to co n sid er w hether o r n o t the food by which he liv e s is l i k e l y t o p o iso n h im . Wholesc^ae fo o d show.Id be a v a ila b le to him w ith o u t th e e x e r c is e o f p r e c is e p re c a u tio n a ry m easures . - With re g a rd to the a c tu a l d an g e rs o f sp ra y rre sld u e s* I may say t h a t in a lm o st fifte e n years of experience* I have not seen a case of lead poisoning or of a rse n ic poisoning derived from the in gestion of f r u i t contam inated w ith spray resid u e s, Moreover I should be disposed to f e e l th a t the statem ent of the tw enty-five p h y sician s, re fe rre d to in your le tte r* th a t they "have never observed or tre a te d a case of arsen ic or lead poisoning e tc ," Is tru e , I have not found any other p h y s ic ia n who has s e e n o r t r e a t e d such c a se s a lth o u g h th e numerous p u b lic a tio n s o f C, U, Meyers (who is n o t a p h y s ic ia n ) and Ills a s s o c ia te s would In d ic a te th a t they have seen numerous exam ples of 11s u b - c l i n i c a l " le a d and a r s e n ic p o is o n in g . J u s t what is meant by "s u b -c lln ic a l" in to x ic a tio n i s not q u ite c l e a r to me* and from some of fche a n a l y t i c a l d a ta s u p p lie d by tb p se men* can n o t f e e l t h a t i t is v e ry c l e a r to them. However th is w ill in d ic a te th a t th e re i s a d iffe re n c e of o pinio n on t h i s s u b j e c t w hich o f f i c i a l a g e n c ie s have to take in to account. A ll of the negative evidence has to be reg ard ed w ith some s k e p tic ism s in c e th e r e a l iss u e has to do w ith whether the q u a n titie s of lead and arse n ic Involved are such as to produce cases in various p arts of th e e p u n try which* f o r a v a r i e t y o f reaso n s* may n o t have been recognized, Those o f us who have s tu d ie d t h i s problem in in d u s tr y know t h a t th e r e are, s a fe l e v e l s o f le a d and arsenjic in ta k e . However in in d u stry exposure is m ainly through in h alatio n * I f these im p e ria ls are ingested* the problem la w holly d i f f e r e n t , and i t seems q u ite c e rta in that, n e ith e r le a d or a rse n ic ad m in istered by mouth are as to x ic , as when I n h a le d , The re a s o n s f o r t h i s a r e qu i t e ap p aren t sin c e i t has been shown th a t a c o n sid e ra b le pro portion of ingested lead trav erses the alim entary tra c t u n a b so rb e d . We have fo u h d , f o r exam ple, t h a t even when s o lu b le le a d s a l t s , in s o l u t i o n , a re a d m in iste re d to human su b je c ts, th a t a very larg e proportion of the1 lead passes the alim entary tr a c t w ithout ab so rp tio n . I t la probable, j 11j p i ; :.llp|rfepr' p ro p o rtio n of lead arsen ate is unabsorbed than is the case w ith these 'I I S me)ii'tjjS|jl i j : , f l | w m:%i t h ! y: :an e x p e r i- : '&!, w a r s e n a te s p ra y s * 0HE 0 1 5 1 0 3 *3 d e a l to do w ith th e m agnitude of th e to x ic ity of th is substance The n e s t q u e s tio n i s th e e x ten t to which abso rp fcion from th e a lim e n ta ry t r a c t i s ta k en up by th e l i v e r and prom ptly e x c re te d from th e body* Mo doubt numerous fa c to rs in flu en c e the f a te of such absorbed lead* and o b v io u s ly p erso n s w ith l i v e r damage w ill n o t behave ao w ell in th is regard as w ill normal persons* You w i l l be i n t e r e s t e d in knowing th a t a very c o n s id e ra b le amount of anim al * e x p e rim e n ta tio n is u n d e r way a t t h i s tim e* R a th er e x te n s iv e work i s b ein g c a r r ie d o u t by th e U nited S ta te s P u b lic H e a lth S e rv ic e u n d e r th e d i r e c t i o n o f Br* R* R* Sayers* in an e f f o r t to determ ine th e e x te n t of lead a b s o rp tio n by e x p e rim e n ta l anim als I t w i l l be some tim e b e fo re th e d a ta on t h i s stu d y a r e a v a ila b le * b u t th e r e s u l t s should be very in te re s tin g and q u ite im portant in re la tio n to t h i s problem . On th e o th e r hand i t i s q u ite c l e a r t h a t th e y w i l l n o t answ er th e q u e s tio n of t2ie r e a c tio n o f th e human b e in g to th e s e poisonous m a te r ia ls * In my o p in io n i t w ill n o t be p o ssib le to a rriv e a t 30und conclusions as to the sa fe ty fa c to r in lead and arse n ic in tak e byjnouth u n t i l e x te n siv e human e x p e rim e n ta tio n has been, c a r r ie d out* I th in k some e x tre m e ly v a lu a b le in fo rm a tio n could' be o b ta in e d by f ie ld stu d ies in the orchard sectio n s during the apple p ic k in g season* One would f in d h e re l a r g e groups o f people e a tin g unwashed f r u i t * and i t would be p o ssib le to study t h e i r p h y s ic a l c o n d itio n and a ls o the m agnitude o f t h e i r le a d a b s o rp tio n and le a d e x c re tio n * I n t h i s Way one co u ld o b ta in d a ta w hich co uld be compared w1 th t h a t detained in in d u s tr y u n d e r c o n d itio n s o f knovrn exposure* and from such inform ation one could determ ine f a ir ly s a tis f a c to r ily the magnitude of th e hazard* You have ask ed my o p in io n as to the maximal q u a n tity of lead a rse n a te which m ight be in - gesfced w ith o u t harm ful e f f e c ts * Anything which I m ight say on th is s u b je c t would be pure guess work s in c e th e re i s no in fo rm a tio n on which fco go* I can say* however* from our experim ental o b servations* th a t i f the t o t a l lead in ta k e p er day by mouth does n o t exceed 1 -1 /2 m illigram s* c a se s o f le a d p o iso n in g w i l l n o t o ccu r among norm al p erso n s* What w i l l happen fco in f a n ts and s ic k p eo p le u n d er th e se c o n d itio n s * I am u n a b le fco say* X would be in c lin e d to expect th a t nothing would occur* b u t th is Is a guess based on numerous i n d i r e c t o b s e rv a tio n s * - ,, r- You m ight he in te r e s te d fu r th e r in knowing th a t th e le a d in ta k e ever a p erio d o f tw en ty -fo u r h o u rs among average American edhlfes v a r ie s from ap p ro x im a tely one-tenth of a m illi^rem to 2 m illigram s per day under present co n d itio n s of food consum ption and d istrib u tio n * Only r a r e ly does th e fewenty-four hour fodd in ta k e coj ta in as much as a m illig ra m o f lead* The average fig u re * how ever,i s approxim ately 0*25 m illig ra m s p er day* The l a r g e r q u a n t i t i e s which* I re p e a t* occur in fre q u e n tly * u s u a lly co in cid e w ith the in g e s tio n of more than u s u a l q u a n t i t i e s of s a la d s and f r u i t * We have seen no k in d ic a t io n in our own d a ta t h a t le a d in ta k e h a s in c re a s e d during the period of the p a st ten years* I should guess, how ever, th a t i f unwashed f r u i t were g e n e ra lly d is trib u te d over the U nited S ta te s , th e average le ad in ta k e would be considerably in creased , I th in k i t might perhaps be increased by as much as fo u r tim es i t s p re se n t m agnitude w ithout g re a t d a n g e r. On th e o th e r h a n d , I can a s s u re you t h a t I would not wish to be re sp o n sib le f o r any s itu a tio n which brought about such an in c r e a s e . F ran k ly I would n o t even e x p e rt' e n t w ith human s u b je c ts on in c re a s e d le a d in ta k e e x c e p t ?3 I could m aintain a co n tin u al m edical supervision of th e ir m etabolic resp o n se , Fvcn under co n d itio n s in which I an ad m in isterin g ore n illig rtr* a day as a so lu b le s a lt. I on m ain tain in g a d - l l y check on th e lo a d in ta k e nr.d o u tp u t, I am c a rr y in g out e o n p lo tc p h y s ic a l e x a m in a tio n s once a week, and 1 a\- w atch ing the blood d aily fo r m icroscopic changoa in d ic a tiv e of increased ! :nd rb n o rp t 1 '.n. T h is w i l l s e rv e to shew- you t h a t in my o o in ic n th e q u e s tio n o f in c re a s e d le a d a b s o rp tio n i s con* s i dor ab ly more than an academic, one* X t r u s t th a t in th is somewhat le n g th y d is c u s s io n , I have g iv e n you a g e n e ra l id e a of my p o in t o f view which i s , p e rh a p s , c o n s e r v a tiv e , b u t in my opinion conservatism Is fu lly ju s tifie d in re la tio n to th is public health-.problem , , . Very tr u ly yours, RAKils S igned: R o b ert A* Kehoe, MD, 0015105