Document GmjbvM0oRzbYQnpgq2o0369nr

Contents Introduction Load: An Essential Metal Measurements >n Man Society Creates Wastes Hbyr tfye'ifjeily Handles inhetetj'^ead Atmospheric Lead Measurements Recent Research Findings Expanded Research Program References fto ester at rife eavar tfapUmw rite* at ttmtdtaa4 chnmma yriiam pmma *#4 nsrf tar rra0U martumg amt rater tatatf aaaitcattcns. Introduction Industry and government, together with medical and research science, are today joining in a oew massive effort to team more about the myriad substances \n the air around us and what they mean to our health and well being. Lead ;is one of those many substances* This basic element is present m the air in, extremely small quantities, us ually in the form of inorganic salts. All studies conducted by government, university, or other research groups have shown that the levels of lead in the general or ambient atr are low and do not constitute a health hazard. Nevertheless, certain pertinent ques tions have been raised and studied. How much lead is in the air? How do the'Concentrations vary from place to place and tune to tuna? Where docs it icome from? Docs it contribute to "smog" formation? How 6ueh lead does man breathe in? What happens M this? What proportion of lead in the general environment comes from the air? What , part cocnsa from liquMrtiiFrom foods? What does re search science know about effects of lead on man? What effect does lead, in the air or elsewhere: have on man? What { researches are now being con ducted? These < andn other questions will be discussed in this booklet. From existing research; data and other information, it will be seen that laid in the iir does not pose a problem for the public under present conditions or m the foreseeable future. Yet care ful attention isbeuig given ud will continue to be given to all { aspects of lead n mil: the environment; including air-borne lead. The Lead Industries Association is constantly seeking to develop, assem ble and disseminate factual informa tion on the many aspects of lead and its uses to society today and to pro vide guidance on proper safeguards to be exercised. This booklet on "Lead and the Atmosphere" is one in a senes being issued by the Lead In dustries Association. Readers are re ferred to the booklet. "Facts About Lead and Industrial Hygiene." for a discussion of the control of lead*in occupational exposures. p\ An Essential Metal Lead is everywhere la the soil, in the air. in the sea. It is in the bodies of city dwellers and in the bodies of natives deep in New Guinea s wilds, one of the moat remote areas in the world, thornsnds of miles from modem civilization. Lead is the basic ingredient in the solder that binds together our elec trorue miracles and is the sheath that protects our intercontinental com munication system. It is the barrier that confines danftrous x-rays and atomic radiation. It is sound-proofini for buildings and ships and jet planes. It is the major component in the bat teries that start our can and it is in tht gasoline that runs our can. It is an essential metal that is too com monly taken for granted by the pub lic. Ber.mi lead is widely and essentially used in modern civiliza tion. them has been scientific interest in watching trends of lead in the en vironment and in people: Several re- PNYC00006569 1 cent studies, both in the United States and tn other countries, have confirmed that lead in the general at* mosphere is it extremely low aver* age levels, about one-hundredth of the concentrations sate for workers in lead industries. These studies also checked lead levels in people from several population .groups and found no indication of increasing body bur* dins ot lead m the general public; Some Pertinent Observations These studies iwiH be discussed in greater detail in later sections, but the following observations are parti* cularly ipertinent: From the American Medical Associ* anon s Committee on Occupational Toxicology i 1966): cades ... If there has been any change, it would appear that at present man is exposed on rhe whole to less lead in his environ ment than he was 20 years ago ... There is however no cause for complacency ..." f3) Recognized Facts About Lead Lead tn the ambient air would be of little interest and of no consequence if it were not for several recognized facts: People in general normally have small amounts of lead m their bod ies and each dav thev take in and excrete tiny amounts of lead thev get'from food, beverage and air. The body is in `lead balance ' un less an individual is subjected to an drink, with a much smaller percent age coming from the air. Studies have shown, however, that the actual quan tity of lead absorbed from the normal atmosphere is so small as to be vir tually undetectable and constitutes no hazard. The question therefore is not whether there is lead tn the environment or m the air pr m people. The questions are whether the lead that is present is of any significance to the health or welfare of people, and whether there is any likelihood that an increase tn lead exposure is possible and poten tially harmful. Fortunately, much authentic data exist to deal with these questions, and more research is in progress ip in crease our present knowledge. < 'The Committee feels obliged to point out that as a result of years of unusually high exposure for a con tinued penod of time, (a) careful clinical study in workers vn the lead industry significant, subtle, and unrecognized or urrecognizable changes are not oc curring tn the general population as a result of rts exposure to en vironmental lead In fact this vast clinical evidence, evaluated bv a great number of clmicailv trained scientist!, suggests that the general public is not now. nor m the im mediate future, facing a lead haz ard." (1) From the U.S. Public Health Service publication Survey of Lead in the Atmosphere of Three Urban Com munities ' t i 963): , ' ` Data from (air samplings) show no h consistent trend in the concen trations of leaA in the atmosphere of.jdM three cute during the past 5 scan ... (BAooti lead levels) art well within the presently accepted range of lead levels for humans and are not significant in terms of a threat of: the occurrence of. lead intoxication wuhin the groups." (2) From the World Health Organization (1965): - " Over-exposure to lead can result in lead intoxication, or plumbum, a condition which n becoming'in creasingly rare, mainly because of then iiprotective measures in leadproducing-and-usmg industries, where over-exposure is most likely to occur. Other than infrequent occuoationali exposure, cases of lead intoxication tare rare and are considered accidental (Cases of childhood lead intoxication occur whieflv among children in shun areas who sometimeseat leaded pamt ch<ps from old buildings. This t\pe of abnormal situation does not involve air-bomc lead and is being brought under control by two coursesnof action: .Non-leadcd paints are standard for building interiors, and urban i.i renewal and rehabilitationnprogramsiare becom ing more widespread ) Lead particles, in vaning sizes and quantities can get into the air from vaiious sources mdudingnnatural soil disturbances, the burning of certain tuels. burning miof waste materials containing lead, some lead-using industries, anduhe com bustion of automobile i gasoline. Measurements in Man Only in the past few decades has it been possible to obtain sound in formation about lead in man and about lead in the environment. This is because of the development of the sensitive techniques of measurement and identification that are required to establish reliable information Armed with the necessary technology, medical and research investigators are able to determine how much lead an average man takes tn. how much he excretes, how much he retains m his bones and various organs, how much is in his Mood and his urmc. These latter two measurements--n blood and urine--are the critical in dicators because it has been shown that an increase of lead in the blood .or urine signals an increased intake of lead in the body from some abnormal exposure. Industrial ex perience has shown that a massive in `There has been no increase m lead The majontv of Icatf in the daily in crease in intake is required to elevate contamination in the last two de take of man comes from food and blood levels significantly, because rhe 1 PNVC00006570 s body retains little of the lead taken m. It has also been found that re* movai of an individual from such exposures will bring his'.blood level back to a normal range. <$i As a re* suit or increasing knowledge concern* >ng the effects of lead. and the use pf proper controls m industry, there has bei&n, i; marked1 .decrease; in the inci dence of industrial lead intoxications over the past 50 ve&n. intake of lead, indicating need for further checking, usually of the blood levels. The above facts have relevance in connection with studies which have measured the amount of lead m the atmosphere of American cities and in the! blood of a number of selected population groups. Data from Many Studies Careful studies over a long period have produced the following facts pertinent to further discussion of lead in t;^fe:iai^.|'(4. ;8)'!' 'l:l^ \ The normal persom takes in. ex cretes and retains some of practicalls everv known element m his eating, drinking and breathing. American adults take m an average or about 330 micrograms of lead datlv andexcreie: thtsisame amount 'hrough normal body functions: thus the boiiv remains in what is called "'ead balance." There is no increase in lead m the normal body ;Wi|ihv^:J'!/ ',:,,r Most of the lead intake comes from food and drink: a very small percentageiifrom air. Lead entering the body from the air ranges from about 15 to 90 micrograms per day. depending upon a number of factors. includmg occupation, place of residence and tvpe of lead in the air. Amount of lead in blood of the average person will range from a low of about 10 to a high of about 30 microgram of lead in 100 granuof blood. Most lead intoxication cases studKid show a range from 150 to 800 micrograms of lead pert 100 grams of blood:,and the lowest blood lead level associated with illness hat been . 'put ".at 80 mierograms, lor ' eifheniadults or children-This lat ter figure is usually taken as an -indication that lead levels are get ting too high. An increase in lead found in the urine isalsoan indicat ion of greater Society Creates Wastes Since the beginning of time, both nature and man have sent gases and dusts into the air. which retains a remarkable facility for disposing of or dispersing them--most of the time, in most places. But this ancient prob lem has acquired a new intensity be cause of man's constant crowding into city areas, his demand for the products of modem industry, and his society's creating more wastes than it is now prepared to dispose of readily. Because man creates wastes in almost everything he does, the complexities of dealing with the problems of air. water, and solid waste pollution aft being increasingly recognised. Efforts to control and reduce man made contributions to air pollution in the United States are beginning to show results, according to; data from the U. S. Department of Health. Edu cation and Welfare's National Air Sampling Network (NASN), which checks the air m some 200 stations located in different parts of the country. The latest reported figures show that then was a slight, though significant, decrease in the average levels of particulates in the air measured from 1957 through 1963. (6) Also listed are some of the things found among the suspended paniculate*, including such metals as arsenic, chromium. copper, iron. lead, manganese, nickel, tin. titanium, vanadium, and zinc. Of lead, the NASN report said: "At most locations less than 1 "c of the particu late matter is lead." This indicates the relative quantitative role of lead in the overall air pollution picture. It has been demonstrated that lead has no role in the formation of photo chemical smog, which is one of the undesirable manifestations of air pol lution. (7) Neither NASN nor any other data show any'general increase m atmo spheric lead in recent years: Currently, there is much interest in the fact that about 99 percent of the gasoline used in automobiles in this country con tains varying amounts of lead anti knock compounds. When combustion engines operate on leaded gaaoftne. some of the lead is exhausted into the air. Cars, of course, are not the enlv source. Others are: Lead-using- in dustrial processes, burning of waste materials containing lead; lead smelting and refining; and burning ct fos sil fuels. Also, some natural sources contribute to lead in the air (8) Modem Gasoflna Need Lead The use of lead is highly important to the efficient and economic production andi^consumption of the high octane fuels required bv modem engines. Lead conserves the amount of crude petroieumii required to make the gasolines which assurc smooth per formance of automotive engines and improve mileage Despite continued research and the testing of manv other substances, no other material has been found as effective. Lead anti-knock compounds were first added ro au'omcitve gasoline in 1923 as a climax to a long and in tensive search for wavi to make a more efficient fuel that would elimin ate harmful engine knock. The public health aspects of the use of leaded gasoline were investigated, and a com mitter appointed by the U.S. Surgeon General rrported in 1926 that no hazard to the public health wis in dicated from the use of leaded gaso line (9) A similar committee in England reported essentially the same in[93Q.UQ1 PNYC00006571 As a result of technological and eco nomic developments n the automo tive and petroleum industries, it was proposed in 195* that the maximum amouht ot lead ann-knock additives used per gallon ot gasoline be in creased from three milliliters (about which go into water settle down rap idly and do not become waterborne, while others become pan of the soil. Air disturbances, caused by winds, storms or autos, may stir up some of these panicles from time to time. The finer particles become pan of the part in the air on man. the amount of lead found in the air has to be weighed against the amount that a man may actually breathe in. retain and absorb. This is very much less than the amounts in the air. a leaspoonrui) per gallon to four mill iculate (natter in the ambient air. and iliters. The then L j Sj Surgeon General are the ones to which people are most named a committee to study the ques likely to be exposed. (13. 14. 15) tion. and m 1959 this committee con curred 'in.Ifieiiiiicrtase. 111>; However, the maximum is used in only a smalt amount of ali gasolinesi and the aver age amount or lead m U S. gasoline m IJ967 ts around 2.5 milliliters per gallon. However, man's breathing defense mechanisms prevent the majority of dust panicles, whether carrvmg lead or not: from< reaching or remaining m the lungs. Small dust panicles (below 0:5 mi ...... --Si r. . . i Atmospheric Lead What happens to the lead m the automobile s gasoline depends largely on crons in size: 1 micron equals 1/1000 of a millimeter and is invisible) tend Measurements the driving pattern and speeds fol to remain suspended in the respired Measurements of atmospheric lead lowed. and the condition and design air and many are exhaled. Larger in cities during the past 20 years of the cars engine and exhaust sys panicles are filtered out in the nose: have shown low levels on the `-aver tem. (12) A pproximateiy 90 percent of panicles age and no definite trend upward or having an average size of 10 microns downward. During combustion of gasoline in the automobile engine, the lead anti knock .compounds change to inor or larger are removed in the nasai air passages. (16) In considering figures on lead in the ambient air. lit should be noted that ganic'salts. part of which are Still, other particles are cleaned out the present accepted safe level for in discharged in the exhaust. In addition bv the respiratory system s network dustrial exposure to lead in air is 200 exceedrnglv small amounts of these of cilia--fine, hair-like structures mierograms of lead per cubic meter lead alkvl compounds in organic which constantly sweep out the of air measured over an tight-hour term mav reach the atmosphere trachea (windpipe) and bronchi fair day. i.e.. when the air of workrooms through the escape of fuel vapor*. tubes) leading to the lungs.; i. contains regularly not more than 200 Still mo're are displaced from the tank during refueling, but these amounts are1 so small they almost defy meas urement irrthe air. (2) .Any panicles (including lead) that do reach the small air sacs m the lungs areijinpaniaJly iremoved by scavenger celts'called phagocytes. These engulf micrograms of inorganic lead per cubic meter pf air. as measured by prescribed methods, cases of lead in toxication do not occur (25) (heipanicies and carry them to a mov In Cincinnati. Ohio, reliable measure ing imucous layer by which they an ments of lead in the air in different moved iiupward by the cilia to the para of the city have been made 1 mouth since 1946. These measurements showed a downward trend in the mam The quantity of lead inhaled ranges residential and basic basin areas from } from less than 15 to 90 mtcrograms 1946 to 1954. Since then they have \ per dav (no doubt being closer to the lower flgure^according to a long-time stayed relatively steady at below two mtcrograms of lead per cubic meter of How the Body v * \ researcher in the field) (8) Of the lead inhaled from the air. about 45 air. Lead concentrations in the com mercial area also show a: downtrend Handles Inhaled Lead percent is exhaled immediately The lung clearance defense mechanisms carrv another 43 percent of the total from about four to two mierograms per cubic meter of air from 1955 to 1962. Studies to determine the six* and chemical composition of lead in the atmosphere have shown that a con siderable percentage of the lead ex hausted by automobiles settles quickly to the ground and is carried off by water or sweepings. Since most of inhaled to the gastrointestinal tract for eventual eliminations The remain ing >0 percent is absorbed into the blood, according to data derived from a lung dynamics task group of the Ini emational; Commission for Radiation Protection. (23) Reasons given for this decline since 1946 are the diminishing uses of solid fuel, better collection and removal of the dusts and smoke from indus trial operations, better enforcement of smokc-alsatemenc lawv and changes in traffic flow and land use these particles are non-soluble, those Thus, in considering the effect of lead in the metropjoiitan area. U ?> <,4;A O l k l J f c i A A w . ' ' : . U 1 . ; PNYC00006572 This decline took place during a period when there was about a two* fold increase m the amount of motor fuel used m the Cincinnati (Hamilton Countvi area and a nearly doubling in tire number of cars. During 1954-55 an examination of lead-m-arr data from 24 u.S. cities was made with the following: ob servations: (IT) In cities up to 2.000.000 population, relatively low lead concentrations from 1.5 to 2 micrograms per cubic meter of air were found: In cities over: 2.000,000 population, the: ranges of lead concentrations and the average amounts of lead ran nigher, with Los AngeJes at an aver age tmedian) of live microgramsper cubic meter: the highest. The Three Chks Satvijr A detailed report on an extensive pro gram of lead-in-air measurements in three major cities was published by the Public Health Service in 1965. (2) The cities were Los Angeles, Cincin nati and Philadelphia, and the report is commonly known as the "Three Cities Survey." The lead measurements were made rrom 3 400 samples collected from the 4 mospne'e regular! y over the course of a veer (from June 1961 through Mas 1*62) from 20 different sites in the three cities Tne ftndirgs were summarized in the report is follows 1 The annual avenge concentration ol lead in rhe aino^ihere ranged from about 2 micropsias per cubic mctisr of air in tl< doMown and inrfSuml are? or C ncuMi to about I in (few outlying a tas oC that risy. The veJune m corresponding areas in Philadelphia ranged frcm 3 to I, and m Lot An geles from 3 to 2. 2 The average concentration of lead in al1 of the samples obtained in each ury was 1 4 micrograms per cubic meter in Cincnnatiyu lub in Phiiadelpt>ia and 5 >n Los Angeles. J The highest concentrations of lead were found in the air during autumn and winter. The highest seasonal con centrations of lead at any station was 2.4 micrograms per cubic meter in Cincinnati. 3.8 in Phiiadelphia, and 4.1 in Los Angeles. "4. The highest monthly concentra tion of any site was 3.1 micrograms per cubic meter in Cincinnati (Octo ber): 4.4 in Philadelphia (October), and 6:4 in Los Angeles (December). "5.: The highest concentration of lead m any one sample was 6.4 micrograms per cubic meter m Cincinnati, 7.6 in Philadelphia, and 11.4 m Los Angeles. *6. The mean concentration of lead found; in heavy traffic ranged from about 14 micrograms per cubic meter on Cincinnati streets through approxi mately 25 on Los Angeles: Freeways, to 44 in a vehicular: tunnel." (Ed. note: This particular finding refers not to the regular monitoring work of the Three Cities survey but to special .tudie*. using mobile samplers, m or near heavy traffic streams m Cin cinnati and Los Angeles,: and to meas urements from another study done in Boston.) *'7. The avenge content of lead in par ticulate matter for all samples was 1.7 percent us Cincinnati. 1.54a Philadel phia. and 2.3 in Los Angeles. ''9. Atmospheric lead concentrations varied during the day: highest concen trations occurred in the early morning. "The concentrations of lead found in the atmosphere in this study were con sistent with those obtained during the same period by the National Air Sam pling Network (NASN) of the Public Health Service. Data from the NASN show no consistent trend1 in the con centrations of lead in the atmospheres of the three cities during ,the pass 5 yean. Data obtained by the Kettering Laboratory indicate that imCincinnati the trend has been downward since 1946." ,i Though these data shewed no trends in accumulation of lead in the air or of lead levels that wouldiaffect the health of the public exposed to the air. it is significant that the report indi cates that such studies should be con tinued. saying that the results "have established a baseline for future inves tigations of these types." The study itself was prompted by a recommendation of the Surgeon Gen eral's committee, previously referred to. which in 1959 concurred in the in crease in the maximum lead content of gasoline. This committee recom mended that the Public Health Serv ice. in cooperation with industries, carryout: ".. Studies to provide more defini tive data on: levels and trends of at mospheric lead contamination in se lected urban areas and of the body burden of lead in selected population group*." (11) .* jHiSiTU. Recent Research Findings In accordance with the latter part of this recommendation from the Sur geon: General's 1959 committee, the Three Cities Survey in Los Angeles. Cincinnati and Philadelphia involved analyses of blood of approximately 2.300 persons and the urine of nearly 1.700 males within the same groups. (2) The persons examined were selected from groups such as policemen on tiraffie beat$. service station and garage workers, commuters to and from sub urbs as well as non-commuters, and some persons with chronic illnesses. The results of this study showed many gradations in lesd levels but no exces sive levels of lead in the blood or tirine of those examined. Among the findings reported were: No relationship was found between blood lead levels and age. In a group of selected chronic dis- pWVC00006573 'jja . ease patients afflicted with respira tory. kidney or bone conditions neither the range of values nor the mean lead concentrations in the blood or urme differed from the general population. These data showed neither unusually high nor low levels of lead m any of these diseased groups. put pf; the'-2..J42 people studied, ohiy l l shpwpd blood lead levels equal to or higher than 60 micro grams per 100 grams of blood, and: these li! were from groups which probablv hadi an occupational ex posure no, lead v garage mechanics, traffic policemen, aircraft workers, etc A few values in excess of 0 06 (60 tmcrograms) are to be expected m a large sample of individuals rep resentmg a vanety of exposures to lead.' the report observed. (A sub sequent follow-up on 7 of the II who could be rechecked showed that the lead levels on second mea surement had fallen into the normal range.) Unne lead levels fell within the fairlv narrow range that is defined asrinormal." The : mean i blood lead levels ported ranged from 111 per 100 grams ofJj| suburban inon-smokai^-lfc'f delphia to 38 microf garage mechanics in (checked previously in 19 is important to recogBtite differences b*tweea~ih*J that special studies on this question "would be desirable.'* Differences in the lead levels in the blood among the various groups in cluded in the Three Cities Survey are indicated in the tabulation below: Mean Blood Lead Level* <Of Selected Subnet Croups tn Thrtt Citits Surety) i In murograms per 100 grams of bloody Lead in Lead in So. Bloo4 so. Blood Cay and Subnet Group Subteeu (Mm) City end Subnet Group Subnets 'Meow Lot Angeles: Aircraft Employ--*- - male 231- female '' 7 ^.Poycemett*^. smoker*^;.-- Policemen *-. Pasadena,dry- i-Jerk; me _____ ____ _ presently accepted iiage of lufed levels for bomajM and s t v j mI sig-niAcant in mi-- of a threat of the occurrence of lead intoxication within the groups,** the Public Health Service report said The mean concentration of Mood lead in smokers was slightly higher than thatof non-smoke/s. Lead levels in blood of women ran slightly lower than for males and the difference was '`remarkably con sistent * No explanation for ihn wa$ noted and lthe report suggests Other St--tfe* on Lead - ,, --"VT(W gra--s at bfood and mean urine T Jkvels oP^T i`tTtcro^5Fhs per liter of The Three Cities Survey finding* wars unite (Ilf ssi 2L*rs * ^ "ans ,n -- : gwptM'MO 20 reicKurams of ` ^ blood as com- In 194] a study of .18* Mexican and- * fnd Id M dOerograma for the rural United State* subjects showed rrwaa- ' blood samples. (19) Pertinent Snd- blood levels of 30 microfranu per infv {mi rhn study are summarized PNYC0C00657A Blood Lead Levels In r*f /'"> c ams ot blood) Cit\ So Samples s/re* Ranfe New- Orleans UO 22 5-50 Dallas 138 18 3-54 Denver 131 19 7-50 Chicago 97 20 5,60 New York i j 2 20 4-53 Cincinnati 13* 2*> 3-51 Rural 102 14 1*35 An earlier study m Switzerland is of relevance because it included mea surements at two periods, one just alter the introduction of lead anti knock additives into Swiss commer cial lgaseline. the other about six years later. <20) The results: Swlii Study: Blood Lead Levels Ave*tVid** Wu rotranu iuf) per 100 from* of blood 194S-19S0 1933-1954 ui ' proHr ut rropl* Medical students 14 \ No abnormal lead exposure) 19 13 27 Garage personnel 23 40 22 31 Thus, there was no change in lead con centrations in the blood during the first six yean tollowing the introduc tion of leaded gpoline in Switzerland. i The digits dearths*shown m the figures is not stg&iBfcuifcV wsm 9WOy CUHBpF* -- The World Health Organization of the United Nations more recently sponsored an international task force study of blood and unne measure ments collected from 16 nations of the world. The findings < published July 1967). averaged by country, showed average lead content in Mood trom a low of 7 micrograms per 100" milliliters or blood among urban Pe ruvians to a high of 28 micrograms tor urban dwellers in Finland. Aver age levels by residence, including urban and rural, reported in micro grams of lead pef lOO milliliters of blood, were: Finland 26; Yugoslavia 24. United Kingdom 23: New Guinea 22; New York City 21. Czechoslo vakia. Egypt and Japan 20; Chile and California 17: Ohio 16; Israel arid Holland 15; Argentina 14; Italy 13; Poland 12: Sweden 10; and Peru 7. The aggregate average wju 17. ( 21) According to Dm. Goldwater and Hoover: of Columbia University, who reported the results of the WHO sur vey. these and other recent investiga tions of 'the lead content in human blood do not differ greatly from those shown by older investigations during the past three decades." The Columbia scientists said that "the lead levels reported m the blood of the New Guinea aborigines are of partic ular interest in that these natives, liv ing m the hills of New Guinea, away from industrialization and motoriza tion. showed blood lead levels higher in range than urban and rural Califor nians. The mean figure of 22 micrograms per 100 millilitersot blood was higher than that of samples from 13 other localities, including California. Ohio and New York City Mean levels from England. Yugoslavia and Fin land are slightly higher than the New Guinea mean/* More:'detailed information from the doctor serving the New Guinea' urea revealed that the environment is com pletely non-mdustnal and free of ga* dine fumes 'Cooking is done in uten sils made of unfinished bamboo tubes. Other domestic utensils are made mostly of wood. These observations serve to illustrate (he difficulties in assuming a simple relationship be^ tweenresiaence and body blood lead levels: ': ; From : these studies: and other exist ing datai it is shown that the quanti ties of lead detected in the atmosphere are well below concentrations that would present health concern to the public, are not mcreasingin general. and are not elevating the body burdens or the general public In a recent review or research on. sources of lead entering the body, the ability of the body to achieve lead balance, andthe overall toxicology or lead; a leading toxicologist >n Cali fornia summarized as follows: i 221 rU has been shown that the popula tion of the United States is m lead balance and the old causes of acute and chronic lead intoxication have been reduced to very low levels h v changes m technology. Lead body burdens of the population have been maintained at the same level for the past 30 yean regardless of the fact that there has been a 2 5-fold mfrease in the use of hi leaded gasolines The bulk of the body burden of lead has been obtained via the food chain and not by inhalation from the environ ment. Although lead is present in thr ambient air. only a small percentage of the inhaled lead is m the cofec' panicle size: for pulmonary retention and even*1 that fraction contributes only an extremely small amount ro the body lead burden. Body defense that environmental lead could induce chronic lead insult in the population Greatly increased exposure to 'ead slowly increases the body burden Kut only' at levels well aboye those en countered m the environment. The supposed chronic intoxication from environmental contamination is a myth, not a fact ' Expanded Research Program Intensive medical studies curried out over a long period of time have estab lished sound criteria for determining safe levels of lead as found m the diet in industrial atmospheres and m man > system. According to known medial PKYC00006575 evidence, compiled from a variety of research in the laboratory jnd on ani mals and human beings, present levels ot lead m the general environment do not present a public health problem. There remain questions about lead in relandn to; human beings that should her investigated.: The lead industry, which has ilong promoted and sup ported sdeh' research, is expanding us etTons to study these questions: Re search studies into health aspects are included m the program or the Inter national Lead Zinc Research Organi zation.Inct i ILZRO h with w hich the Lead Industries Association is affili ated. ILZRO is now stepping up its efforts concerning investigations into lead and human health. One research protect of immediacy and pertinence!rs seeking to determme the smallest amount of lead in air which man'breathes that would have an effect on the possible accumulation ot lead in i the blood. ProMesi of AaMnt Air Standards The pertinence of such research re lates w\ efforts by some: air: pollution control ^authorities !. to i set ambient air standards for cenam substances which, in excess in the atmosphere, are considered pollutants. Setting such standards for lead at this time calls ror guesswork, when what is needed is: solid iinformatiom bascd ofl scien tific research As has been said, in in dustrial exposures, the accepted safe level for a working lifetime a 200 micrcgrame per cubic meter of air in the workroom based on an eight-hour day. fti'e-dnjn week. Obviously* this would nob wfiiisnly *pfry to air which peoghr ten breathing 24 hours a day. seven day* a week. Nor is it scientifically acceptable merely to as sume that since a full 168-tour week is roughly four times a 40-hour week, then there would be logic in setting the full-tune level at about one-fourth, or 30 rn'icrograms per cubic meter of air.- FulMime exposure compared with exposure and withdrawal from expo sure poses different problems in elim ination of lead. Tests with Honan Subjects {Lettering Laboratory at the Uni versity of Cincinnati is carrying on experiments with human subjects that involve nearly full-time exposure to atmospheres with known lead concen trations. The object is to determine what concentration of lead in the air a person breathes may start an up turn im measurable lead m the per sons blood. From this worki spon sored m part by the U.S. Public Health Service, it is hoped that a reasonable ' yardstick can be developed for setting ambient air standards for lead, where: desired, as is being done for many other, substances found in the air. The > fact that there is no scientific, basis iinow far setting any such: figure is conceded by the state of California which has been studying the situation for some years, and has not as yet found any acceptable method for de termining a lead/air standard, al though standards have been setJor a number of other substances emitted into the air from various sources. During 1967. however, itwo states: did adopt: a figure for lead in the ambient air. despite admitted lack of founda tion for these figures. The state of Pennsylvania set a tentative" limit of five micrograms per cubic meter of air avenged over a 30-day period. Al though this figure v m said to be derived from preliminary datt devel oped by Dr. Robert Kthoe of Ketter ing Laboratory. Dr. Kthoe personally appeared before the Pennsylvania Department of Health hearings to dis pute the application of his data in this way and to testify that research m its present stage showed the figure W be; too |low. He added, that any figure calculated on present data "is not necessarily or even probably cor rect." (231 The state of Montana later adopted this:isime'standard, upon recommen dation of the U S. Public Health Serv ice. even though the PHS spokesman gave no scientific reason for this figure and told the State Board of Health that: Information of the effects ot lead m the atmosphere is indeed sparse As far as we are aware, there are no cases of clinical lead poison ing that can be attributed to expo sure to lead in the ambient atmos phere, The levels present, we found m most places, are thought to be safe, although there are some Places where exposures are subject to con siderable question . Allowing ror wide variability among individual persons, and a wide variability or exposures, and' injecting a modest factor ot safety, we reel that 5 mi- crograms per cubic: meter or lead for monthly average or exposure s\ probably safe." But nowhere did this spokeman give any data or backing;for this figure as against any other valucTwhether higher or lower. i The human exposure; studies which are continuing at Kettering Labora tory are expected:: to shed more sci entific light on this complex subject when the experiments are completed.. The question of whether the relatively small amounts of lead taken m hv the average: adufti1 from air would have an effect on those particularly susceptible to disease has been at least partially answered by the Three Citics Survey in its study of patients with diseases affecting liver, kidneyj ilong on;:,bone. These patients showed no unusual blood lead accumulations. Stagy of TEL Workers Another question that has been raised concerns exposure of long duration to relatively low levels of lead, such as might occur m persons exposed to continued high levelsiof air pollution, An analysis of the health records or persons occupationally exposed to lead for many years does not indicate a correlation between such exposure and any health problem. The results of one such thorough anal ysts was reported at the October 1966 meeting of the Industrial Hygiene Foundation. (241 Thu was the study of employees m the tetraethyl lead (TEL) production facilities of a ma jor producing company. The TEL PNYC00006576 group was suitable for this analysis because m addition to their normal exposure to lead, they were subject to some further exposure on their jobs: also, health data existed for the work* ers over their entire period of em ployment. The study covered 1.120 men: 348 currentlv working in the TEL area who had been there six months or mors: 348 men who had not had occupa tional lead exposure and who served as controls: and 424 men who had for merly worked in the TEL area for at least six months or more in the past. The firs.: two groups were matched according to race, age: and length of service with the company. Measure ment of lead in unne excretions for TEL workers was almost double that of controls, showing a significant dif* lerence in lead absorption between the exposed and unexposed groups. Company medical records of the, workers were reviewed for informa tion on the following items history, of important chrome disease, height and weight, blood pressures, hemo globin determinations.: white blood cell counts, and electrocardiographic abnormalities: For the most common chronic dis eases. the TEL workers and prior TEL workers both showed lower preva lence than that of the controls, the study found. Theusummary of the findings said that though TEL production* workan had an average, urinary lead excratkaa. more than ,doubt* that of tht gnml population, "nop advene effect on health of this deggaacf teadexpownt wasitfcweaedii? Research W Pbevtda Aim. The need for continuing research was a consrnsusof the Public Health Serv ice symposium on environmental lead contamination held in December 1965 in Washington A panel report noted that no explicit evidence was pro* senied that suggested present lead burdem werej' associated with any major contribution to disease in the popula tion. The report said the possibility ; could not be excluded that present , lead intakes might, in undetected fash- ' ion. be related to certain ailments. The ' panel recommended epidemiological 1 and laboratory studies to find out I more about possible effects of present j or higher lead levels on man. I Other recommendations included: j JMore accurate definition of the effec- tive absorption of lead by inhalation; development of techniques for better assessment of body burden of lead, and ``the biological mobility of lead in its several biological compartments, and continued, intensified studies on the relative contribution to the bios phere of lead from geological and technological sources." With these recommendations, the lead industry is in accord, ft also expects that the research that it is sponsoring both alone and in participation with other igroups. or the work being done byi, other organizations. will help pro vide answers to the questions that have been raised. The lead industry for many yean has supported scientific studies of all as pects of the use of lead. New and ex panded programs arc continuing through the International Lead Zinc Research Organization. These include plans to participate in a major study similar to the Three Cities Survey pre viously described,! but on an expanded basis. Other projects will utilize new techniques, such as isotopic ratios, for measuring sources of lead in the en vironment. and will open up new av enues for keeping up with information about man s use of lead, especially about lead in the atmosphere. References 1. Committee on Occupational Toxico logy , of Council on Occupational Health. American Medical Associa tion. Comment. Archives of Environ mental Health. 12:273. Februarv 1966. 2."U.S. Public Health Service. Survey of Lead Ut tbe Atmosphere of Three L rbaa CommnnJtica, PHS Publication No. 999-AP-12. January 1965. 3. World Health Organization. No In crease ia Lead Contamination Found by WHO lavefUgadon. Press retease WHO 36, December 15. 1965. 4. Kehoe. Robert A. The HarfceSi Leetarts, 196b--The Metabotfam yI Lead taiMaa in Health aad Dfaesae. Jour nal of the Royal Institute of Public Health aad Hygiene. 1961. 5. Kehoe; Robert A, Metabolism of Lead n Under Abaormai Condition*. Archives; of, Environmental Health 8:235-243. February 1964. 6. US. Public Health Service. Air PotlotioaiMcasartmeotsof the National Air Semptiag Network--Analyses of S--psaditl Particulates. 1963. Robert A: Taft Sanitary Engineering Center. Cincm'hati. Ohio. 7. Worms. F.V., Bolzt. Calvin and Goodwin: John T. Jr. .Smog Chamber Studlee of Unleaded versus Leaded Faeftk [.Industrial and Engineering Chemikry!50:673. April 1958. 8. U-S. Public Health Service. Sympeetom oa Eavhoomtntai Lead Contaaafaajtioa h December 13-15:. 19^5>. Public,it,iHealth: Service Publication' No. 1440. March 1966. 9. U 5. Public Health Service. The I s* of Tttraefhyl Lead he Gasoline: la Refadea te PaMc : Health. Public HtaJth!ftu(letinNo.l63. 1926. U>. EMI Report of tbe Departmental ComminM oa Ethyl Petrol. Hi* Majesty's Stationery Office. London. 1930; PN*C000065t7 11. U S. Public Health Service. Pnbdc Health Aspect* of Increasing Tetra ethyl Lead Cooient in Motor fwi Public Health Service Publication No. 712. 1959. 2!. Goldwater. Leonard J. and Hoover. A. Walter. Aa International Study of "Normal" Levels of Lead la Blood ad Urine. Archives of Environ mental Health 15:60-63, July [967. 12. Hirschler. DA.. Gilbert.' L.F.. Lamb, FW, and Niebvlski; L. Particulate Lead ConpoeiMb in AatoaobQt Ex* hanst Gas. Industrial Engineering Chemistry *9: U 31 - 1142* 1957. 22. * Haley, Thomas J. Chronic Lead la* tozkation from Eavfronaental Coatauaiaattoa: Myth or Fact? Archives of Environmental Health. VoL 12, June 1966. 13. `Robinson. E. and Ludwig, F.L. Size Dmribotkm of Atmospheric Lead Aerosob. Stanford Research Institute; Menlo Park:. Cah, 36 pp.; April 1964: 23. aKehoe, Robert A. TestUaony at Hear* lag of Pennsylvania Department of Health; Harrisburg, January 19. 1967. 14. Cannon. H.L. and Bowles. J M. Con* 24. Stopps. Gordon J.. Maxdeld. Mary lamination of Vegetation by Tetra* E.. McLaughlin, Martha, and PelL ethyl Lead. Science 137.765-766. Sidney. Lead Research: CarrvatMed* 1962. kal Davetopmeam. Presented at 3lst 15. '`Robinson; E.. Ludwig, F.L.. De Vries; 1.E-; and Hopkins; T.E. ViiadoM of Atmospheric Lea4 Coe* annual meeting of Industrial Hygiene Foundation. Pittsburgh. Pa.. October 18-19, 1966. centmtion sod Type Whh fimkh 25. American Conference of Govern - Size. Stanford Research Institute. ment Industrial Hygienists, 1014 Menlo Park.. Cal., 80 pp.. November Broadway; Cincinnati. O. 45202. 1963. Threshold Uadi Vataesfor 1967; 16. Hatch; T.F: and Gross. P. Pnlmonary Deposition aod Retention of Inhaled Aerosols. Academic Press. New York. 1964. 17. Cholak.: J..,Schafer; LJ.. and Ster ling. T.D. The Lead Content of the Atmosphere; Journal of the Air Polluuon Control Association 11(6): 281-28*. June 1961. 18. Cholak. J and Bambach. K. Mssnttani of laMil Lead Erpnsnn by Analyses of Btood sad Eacnh el Workmen. Journal of Industrial Hygieneaiid Tctteotaft 23:47*34> 1943. 19. aHofreuuuv IXMsCCaseott^BJ^ Kaanan. !R.G,, md Xhttrav C Tim PnMk rii<dW %sldisei s ef Ahmi> phette LsndC Archfrta of Eavutmmental Health J.S66-57A, 1961. 20. Report of the Saks Leaded GamBar Commiuioa m th* Federal Conadl ea im! AcdvMas Mg the Mod 1947*1966; Mitteilungta aus diem Gcbiete der. Lebensmictetuncenuchung und Hygiene (Bern! 52(3); 135244. 1961. Other References "Lead i Industries Association. Inc., New York City. Farm Ahoat Land and tndnstitil Hygiene. 1965. Task Group on Lung Dynamics for Committer II. Health Physics 12(2):l73*208. 1966. Newshotae. A. Tha Seary ef Madam Pwstadha Medkfcm; Tha Williams and WUkias Company. 1929. Air Madia World Health Organi zation Monograph Sanaa No, 46, Columbia Unirenuy Press; New York, 1961. *5chroeder; H. A. and BaJawa, J. J. Ahnormd Tram Metals In Mam Lead. Journal of Chronic Diseases (St. Louis) 14<4):40M2S, October 1961. Bagchi, K.N.. Ganguly. H.D.. and Sudor. J.N. Land hi Food, lodian Journal lof Medical Research 28:441* 450. 1940. Warren. H.V, and Delavauit. R.E. Observations os me Biogeocbemistry of Lead is Canada. Transactions of the Royal Society of Canada 54:1120. 1960. Warren. H.V. Trace Elements and Epidemiology. Journal of the College of General Practitioners 6:517-531. 1963. "Ziegfeld. R.L. Importance and Uses of Lead. Archives of Environmental Health 8:202*212. February 1964. Darum. W.H. and Haffty. J. Occur* react of Minor Elements in Water. U S. Geological Survey. Circular 445. 1961. Kehoe. Robert A. Normal Metabol ism of Lead. Archives e>f Environ mental Health 8:232*233, February 1964. r Nusbaum. R.E..' Butt R.M. and Gil- i mour. T.C. Tract Metal Stadles of Bona m Relationship to Air Polio* : tmti .Expos--; Archives of Environ* mental Health 10:227-232. Februarv 1965. Lane, R. Health Control la Inorganic . Lead ladosuiu. Archives of Environ mental Health 8.243-250. February 1964. Calaadra. J. C. Lead in tha Enriroamsnfc Presented at 38th annual coeating of Tha Lead Industries As* soeiation, Inc.. Sc. Louis. Mo.. March 31-April J. 1966. Patterson, C.C. Contaminated and Natural Land Environments of Man. ; Archives of Environmental Health 11:344, September 1965. Kcbct, Robert A., Thaznann. Fred erick and Cholak. J. On gift Noma) Ahtarpdcn and Excretion of Lead. L Lead Abaecptioa and Excretion in PrimMve Ufa, Journal of Industrial Hygiaha 15:257*272. 1933. `Available from The Lead Industries Association, Inc. PNYC000G6578