Document zd8m0pg8BX2bDY8nJE9LBZKmm

D ecem ber 3, 1953 M r. Arthur I,. D avis C onsulting C hem ist 1125 M ontview D rive H olston K ills 1 K noxville 14, T ennessee . Dear M r. D avis: Y our le t t e r o O cto b er 14, c o n c e r n in g w h ich a p o s t c a rd w a s s e n t to m e recen tly (recen tly returned by m e), would see m to req uire som e reoly from m e, and I judge that you have been concerned because no rep ly w as forthcom ing. U nfortunately, I have been abroad sin ce the end o S ep tem b er, and, w h ile v a rio u s m e m b er s of the sta ff have handled most, of the m atters that cam e up in m y a b sen ce, no one undertook to deal with your su ggestion s. I can understand their reluctance to do so when I consider m y own reaction s to them , since I'm afraid I do not understand ju st what you a re getting at. A s it seem s to m e, in vestigators are attem pting to get together certain facts about a ir pollution on a fa ir ly broad b a se. Som e have tried to draw conclusions from inform ation that can only be regarded as frag m e n ta r y . In m y v ie w , at p r e se n t, no p a r tic u la r p r o fit w ill c o m e fr o m em ploying various m eans of exp ressin g these fragm entary data. W hile I w elcom e and encourage new w ays of looking at the m a tter, I cannot escape the feelin g that what we require is not m ore theory, but m ore facts. . : * There a re sev e r a l m atters in your ob servation s on which I m ay com m ent. ' .1. I d on 't b e lie v e th at there is a n y r e a l v ir tu e , fr o m the a s p e c t of * accuracy,, in exp ressin g the concentration of air-pollutants in term s of 10 cubic m e te r s of a ir , e sp e c ia lly in com m u nity a tm o sp h ere, sin c e the figu re at b est is inaccurate in its relationship to an 8 -hour day, and sin ce it has no m eaning in relation to the hours of the day in which one m ay be breathing com m unity a tm o sp h ere. It m ak es ju st one m ore a rb itra ry unit to explain to n o n -p h y sio lo g ica l tech n ical p eop le. It is b etter, I b elieve, fo r a ll p u rp oses, to u se a conventional exp ression which can be understood by ev ery one at sight. T here is som e ju stification , in tra d itio n and perhaps a ls o in con cep t, fo r ad h erin g to the 10 cu b ic m e te r standard in s tr ic t relation to occupational ex p o su re, but even th is, in term s of accu racy, is a dubious proced u re, sin ce it introduces one additional erro r into the pattern of individual exposure. I am so rry that the idea was ever introduced into p ractice. KE 0015203 M r. A r th u r L. D av is - (2) - D e c e m b e r 3, 1953 ; 2 . I do not see the d esira b ility of exp ressin g the concentration of m aterials in fe e a tm o sp h ere in terra s of m o le c u le s , if fo r no other r e a so n than that {1} it g iv e s a f a ls e s e n s e of p r e c is io n , and {2) it im p lie s th at the m o le c u le s a rc sep arate en tities w hich, in the c a se of highly a sso c ia te d com pounds, is not tru e. 1 think it better net to go beyond the ex p ressio n of concentration in sim p le v o lu m etric, w eigh t-volu m e, or w eight-w eigh t te r m s. 3. I d istin ctly do not lik e theddea of con sid erin g the to xicologic sign ifican ce of the a tm o s p h e ric concentration of elem en ts or com pounds in term s of the e s ti m a te d num bers of the c e llu la r u n its of the an im al o rg a n ism -which is subjected to exp osu re. The p h ysiologic im p lication of such a procedure is m islea d in g , in that the m a teria ls are ra rely distributed even ly, or in any approxim ation to uniform ity, in the various tissu e s and flu id s. Sam e of the m a te r ia ls n ev er p en etra te into any c e ll, and th e ir c o u r se in the body is such th at m any of th em n e v e r h ave a c c e s s to m any of th e body c e l l s . It is a function of toxicological in vestigation to find out where and by what m eans the variou s su b stan ces exert- th eir influence. 4. The concept of the influence of toxic m aterials on enzym e system s is, Of c o u r s e , tim e -h o n o r e d , and it h a s b e e n su p p o rted w a ll by q u ite a n u m b er o f in v e s t ig a t io n s . (I b e lie v e t h e r e - is no e v id e n c e th at le a d in h ib its e n z y m e sy ste m s in w hich ~H groups a re concerned. C ertainly th is is not its im p or tant point of attack. ) 5. In the m a tter of the p h y sio lo g ic e ffe c ts of v a rio u s co n cen tra tio n s of ch lorid es and flu o rid es, such a s th ose contained p resen tly in com m unity su p p lie s of d rin k in g w a te r , w h e th e r n a tu ra l -within, lim it s , o r added w ith in p resen tly approved lim its, the evidence of exp erience and investigation is m uch too com prehensive to be shaken by im p lications based on such calcu lation s as you have m ade. H isto rica lly , man, livin g on this planet, has a lw a y s had to d ea l with, c h lo r id e s and flu o r id e s w ith in c e r ta in lim its of concentration. There is not the slig h test reason , at p resent, to doubt that the introduction of fluoride into the drinking w ater, within the lim its recom m ended and controlled, is both safe and advantageous to m an. A s to the chloride^ the situation is even c le a r e r , hi that it is difficult to adm inister a toxic amount of chloride to a healthy anim al, including m an, w hereas the p resen ce of chlorides w ithin.the body is e ssen tia l, and the norm al range of the concentration is quite appreciable. b. One of the m ost sign ifican t m a tters, with referen ce to the toxicology of a ir pollution, is that of the com bined effects of m any su b stan ces to w hich the organ ism is exposed sim u ltan eou sly or se r ia lly . Until som ething m ore is known h e r e, we shall have to indulge in considerab le speculation. Another factor in the m atter is that of su scep tib ility. We shall have to work out what is m eant, physiologically, by such susceptibility. Mr. Arthur L. Davis - (3) - D ecem ber 3, 1953 I should not w ish to convey the idea that I am opposed to ch em ical and p h y sio lo g ica l sp ecu lation in th is fie ld of in v estig a tio n . R athe?,I have attem pted to suggest that we need not m ake the speculation too com plicated until we have accum ulated a greater body of sim ple facts based on ob serv a tio n and in vestigation . You r efer to the inability of p h ysician s to diagnose and treat flu o ro sis. May I point out that th is is not surprisin g, sin ce acute fluoride poisoiung is quite rare in the exp erien ce of p h ysician s, w hile chronic flu o ro jis is practically non -existen t as a clin ical entity. C ordially yours, RAK ei Robert A. Kehoe, M. D. KE 0015210