Document v1pr09a3wO92mb2pEexb3pdKq

' f? max& iratfMv ;>r V,v v(" -i ^ Ant ikno c k ,' gipgjptlf**W!' MppHffpPMa WWW wpWq| ( - fycr. 3 ar :; . ' 4 2 c o mpo unds AND PUBLIC HEALTH tatenshre mtial stslies.stow4 f that leal alkyls ia fajoluie and leal compouals to automobile exhaust create m hazarlt I; Ratoit A. KdMi HA BmW, T1m KrtWrioj Cnlcpri Mcdicim, IMwnMx of ilwimMl \ .- % : _;1 N 320.01 -y: m -V: $ .*:?: Antiknock Compounds and Public Health9 At t h is t imi of increasing inleteu in ihc ** cleanlineu sod purity of the ad--particu larly is tod around the country's larger cities-- Ihc amount and compmilion of automobile ex haust discharged into the atmosphere h widely discussed Since tetraethyl lead, letramethyl lead and related lead alkyl* are used at antiknock compoundt in practically all motor gasoline*. i|umiioiH have been raised about the amount and poMihlc effects of lead compounds that may be finding their nay into the air through exhaust Despite impressions to the contrary, loti of inforetatioQ is available on the concentration of lead compounds in the atmosphere and on their relatioa to public health. Tetraethyl lead and other lead alkyl anti knock compoundt have been among the mod thoroughly Utidied industrial products, from the standpoint of public health. In the last JJ yearv Since leaded gasoline canx into genera] use is the mid-1920a, more time, money and effort have been devoted to their medical aspects than to any other contemporary product, except the practical application of atonic energy. The concentrations of lead from all sources generally found in the air of American chics are loss. The amounts of lead to which the general population is exposed from xD sources-- luJuduig foods and beverage*--ate below hazardous limits. There has been no demonstrable change on the part of the avenge American, either in hi* intake or output of lead, or hi (be amount retained in his body, in the lad 20 years or more. An understanding of the sources of lend and of the body's intake and absorption of k makes these statements more meaningful Here arc facts to help provide web an undemanding: Fust, lead antiknock compound* art only one source of the total lead in the atmosphere. Just how much of a source, k is difficult to estimate since accurate measurement methods were not la asutylaj M raariaSraS.ai la ISm afaifkiri. TW Sr IVhrnK, r (Wawl l'a<a at Msdktm km wtyaad c Manufacturer! Sponsor Research Most of the medical research Into antiknock compounds baa been sponsored and financed by antiknock compound manufacturers and much of h has been done by The Kettering Laboratory fat the College of Medicine at the University of Cincinnati. Findings have been published in scirntific and medical journals and have been mad* available to Investigators and to public health aulharkict. These findings have demonstrated consistent ly that: t,c*d compounds discharged from the ex haust of automobile* have not created n harard to tha health of the public. ^^dcveloped until after leaded gasoline had ome the other hand, from leu than 35 lo at much at imo widespread use. However. fa fa a well knon SO percent of the lead in typical city air may be fact that lead in the air cornea from the combus absorbed by the respiratory tract Bui remem tion of wood, coal and vegetable mailer, from ber, the amount of lead taken in from food and lead in the toil, from mao-made producti con drink h from four to 20 times greater than that taining lead, and from lead in meteorites. taken in from the air. Second, far mote lead fa taken into the body from food, water and other beveraget than from Absorption from Food nod Air the air. In many observations it hai been found Ai a result, the average person in the general that lead Intake from food and drink average! population may. in an ordinary day, absorb ' ^r* -,T~- ';r*y^'7'< o.--' one-third of a milligram a day, while intake from breathing fa aa Ujtlc aa one-twentieth of that amount, or aa much, perhaps. aa one-fourth of it, depending on where and how the boura of the about SO micrograms (0.03 milligrams) of lead through his digestive tract and somewhat mom or lest (usually lest) Iron the air. In other worth, lead in food and borages fa just about day are spent. (The amount of lead in the air as important as lead in the air in contributing to varica greatly in different areas of the tame city and respiratory volume varica greatly with the tire and activfaica of an individual.) day-to-day abiorptioa by the general public. But regardleu of the source of the lead which the average person takes in. fa has been found in However, theamount of lead ibnrM by the repeated thorough tfudica that the quantities of PWpfal'Kfl aa the amount that nem the respir lead ejected from the body daily so netrfy equal atory and digestive yatcrm should be carefully the quantities injested that any accumulation-- ^considered. 9 Generally, less than 10 percent of the lead even in a lifetime--fa too small to be detected. These accsimulaiions. therefore, have little If any physiological significance. > ;4m I Speaking of the amount of lead which b in haled. h hat been found that concentrations in urban atmospheres vary widely. From time to time. unuuiaUy ht[h values have been reported and hate occasionally been given more tigniA- cancc than they deverve. Generally, however, the lead coment of the air of rcpmcnuiive American cnica h very low. In thi< connection- it hat been found that the atmotpherc of individual American cilia may contain an average of from one to tit micro- pamt of lead per cubic meter of air, although it it doubtful that the average it at high at tit in any one city. Tboc averaga are far bclcw the cooccntra- lioo of 200 microgramt per cubic meter which it lbe accepted U. S. tpcctfication for tale con centration! of lead in the air in industrial plants. Tbit spcciAcaiioo doa Dot apply to the gen eral atmosphere, of counc. Instead. it taka into oontidcntioa the thoncr and more intermittent occupational exposure to lead (approximately tO hours a week ) of workers, at opposed to coo- tunt exposure to the general atmoapherc by the population a* a whole.... ,< jg"? - The real criterion of safety, insofar at human exposure to lead it concerned, b freedom from a rale of intake and absorption that wiO cause progressive accumulation of lead in the body over a long period of lime. Under present gen eral conditions of exposure, outside the lead in dustries. no such accumulation occurs. Looking ahead, it is possible to recognize any potential threat well ia advance of its possible materia(uation and there h ample lime and sat isfactory experimental means for obtaining in formation rerptired to establish a standard that will provide a suitable margin of safety. In considering I he part lead compounds from automobile exhaust play In the overall lead con tent of the atmosphere, the results of peilodic and fairly comprehensive Investigations in the city of Cincinnati are quite revealing. Since the late IV40s, while there hat been progressive In- creases in consumption of gasoline and in vehtcular traffic, there has been a significant reduction in the lead content of the air. The reduction can be traced, in pan. at least, to reduction in airborne lead contributed by coal combustion. It appears that the amount of lead in the Cincinnati atmosphere from the combus tion of coal had at doe time been at lean the equivalent of that from automobile exhaust' This fact alone helps put the subject of lead ia the air in more balanced perspective. Of perhaps even more pertinent significance are these findings: a Available data iodicale that there b no evi dence that groups of people living ia Los An geles. a so-called "smog" area, are absorbing lead into their bodies at a rate significantly greater than arc corresponding groups in Cin cinnati. Studies of men working in outdoor areas of comparatively heavy automobile UaAc repeal the pattern of "normal' findings on the Amer ican scene for the last Kkdd years, so far lead absorption b concerned. Of further interest--especially so the oil in-; dustty--it the fact that while lead from automo bile exhaust ha created no public health harard. neither hat unhurried leaded gasoline. The low concentration of lead alkyls fas com mercial gasoline insures that there b no harard of lead absorption ia association with the usual procedures of its commercial distribution. No case of tetraethyl lead poisoning has occurred among the thousands of persons who have trans ported and dispensed leaded gasoline* In the ordinary operations of the American petroleum Industry. Similarly, antiknock compounds. a such, an not found in the ambient atmosphere of chics in more than minute traces, since aU but very minute quantities are burned to inorganic lead in the Interna! combustion engines of automo biles. Accordingly, these compounds, of them selves. present no hazard to the public health. 7F!P IIC T ,"fI tUfruwrd ha l*i InJustrias AsmeUtkia. lac, hi StsJisoa Avenue. New Vat 17. N Y, Inna die Me) iuM IV*' Iw <4 I TtlYt. NEWS.