Document JJnrBbr2vkga6vJN7vDow5X16

/ 7-*"i <sm> 571UME3JS02 E. 1. pu Po n t d e Ne mo u r s Sc Pp m'p a n y (MCORPOHATCn Wil min g t o n , De l a w a r e issas CHEMICALS AND FIGMENTS DEPARTMENT May 15, 1990 TO; B. W, KARKH C,,r^_BElNHM?.D.T,-,^HASKELL G. L. KENNEDY, HASKELL R. N, LXGO, MEDICAL A. J. HAY, MEDICAL T. J. NELSON, MEDICAL G. J. MEYER, PA K, H. FORTE, PA G, HIDALGO, TEMSA E. FLORES, TEMSA E, JACOBS B. CIJRIEL, DUPSA R. W. BEGLAND J. S. THACKRAH N. C, JACKSON O. PLIEGO, TEMSA A. B. PALMER PROM; C. R. HOTTER IDZRQ..PAjPER Most of you are aware that ILZRO is preparing a position paper on lead antiknocks. An important part of this paper is the subject of health risks related to lead. A draft of the paper was sent to its sponsors in February 1990 and Gerard Pfeifer, Senior Research Associate, Ethyl Corporation Health and Environmental Department, has made numerous suggestions for improvements. The proposed revision by Dr. Pfeifer for the section "Relationship Between Lead in Gasoline' and Blood Level" is extracted from his general comments on the paper. Dr. Pfeifer sfas one of the invited guests at the March 16, ,1990 seminar "The Health and Cancer Risks of Lead" which most of you attended. Dr, Pfeifer has given me permission to circulate his comments, if you have questions or comments he can be reached on (504) 388-7565. CRH/krw41 N 27670 DUP040010913 E I H U :ns? ___________ -- n rrn ---- -- (Ti). 5, L'!H0!51 trt,28p3H2.g PAGE l? -6- B. gel^j.onghlP_Befcween_i,aAd.JL&--Casoline and Blood Lead Blood lead levels in several countries have declined over the past several decades, whether or net gasoline lead usage decreased. exposure to lead. Tor instance, in the United States during the 1970's, 14 U.S. government regulations were enforced with the specific goal of reducing lead exposure from air, water, food, and non-food media. x The U.S. Food -and Ding Administration also initiated a program during this time which successfully reduced the lead content of a variety of foods. In 1981, Jelinek reported that lead levels in food for infants was only 10 to 20 percent as high as they were in 1972 because of technological changes in the infant food industry. Boyer and Johnson of the Food and Drug Administration (1982) reported that mean levels 'of lead, in eight canned foods were reduced by 50 percent between 1974 and 1SS0. Other governmental and industry programs HJgiip ltf:|fgb|iSj products in thii; SPJs; amid- A survey of blood lead levels reported in the literature shows an. apparent decline in blood, lead levels over the past several decades (Figurjs S) . 'This decline occurred even as gasoline lead usage was ! ;.:'^S||3*iiijehi: lh 4. tJft':r!iiyb in gasoline lead usagef wlks, particularly dramatic from about 1940 to 1370 as blood i^^icl:11- jin 1 1,1 ` Similar blood lead declines have been reported in the U.K. Oxley (1982) reported a 30% decline in blood lead levels in males presenting1 fot pre-employment physicals at one plant between 1967-69 ah4;:||l||li||;|1!,!ippiptment;' tef "'the 'lEnvironment .reported si i'^ ||pp,i.:,r^i^|::^:|r^ raEfipiU 1^?9: to i9;B;6" (Quinn and. Delves, ^p^pw^<3.:. a.-' piiro.g-rre'siSii^y'ijS- decipesbe in mean blood lead v,alu`es ir) children from 20.7 ug/100 ml in 1973 (Earltrop et al., 1975>) to T4.7 in 1977 (strehlow and Barltrcp, 1978) to 9.8 in i960 (Str'ehlow and iBarltrop, 1983). Elwood (1983) showed a decline of 30% in the! ,blOcSd-lead concentrations of women in Wales between 1972 and 1932. This1,.amount of lead in gasoline used during this period remained relatively constant. Although lead concentration in '|3'rtrpii 'salies!. :pslnne4r.' fcB&0xop, -3L^|0|B|li; w i;t||refgre., 'tf^erei i^eli^lcn^^i?:''between the fall in blloc'd lead levels in the U.K. and lead usage in gasoline. Trends in blood lead levels were measured in Christ Church, New Zealand s^ndj, ekyirpnsj. by piJnten et 'al i (.isjlfil)Blood isitd levels were monitored beginning in 1974 and showed, a significant decrease, from S||p. w .'Ih.a popjila'^'ioft'w^i^ jiad' essentially' no! exposure to lead other than that from the general nvirphlaplhl!!., ,!,:jp|pd` llead JeytJs feit'ifti adplli linales :bhd pefekles N 27670.01 DUP040010914 m E T H V t C 0 I? P (IU). 5, i. ^0 18J5.2 HO.2068314266 PAGE 3 W7i greater than seventeen years of age by 42% and in school and pre-school children greater than nine months by 44% and 46% respectively. The investigators indicated that the decrease was not related to changed in laboratory performance, population sample selection or lead content in gasoline which remained at 0.84'g/l throughout this period. Rather the decrease seems to have occurred because lead had been eliminated or reduced in paint, toys, plastics, glazes and children's food cans. ^ There have been several studies specifically designed to evaluate the effect of -changes in gasoline lead usage on blood lead levels in the general population. The first of these was carried out in Frankfurt, West Germany by Sinn (1980) . This study was designed to determine the effects of lowering allowable lead levels in gasoline from 0.4 g Pb/liter to 0.15 g Pb/liter on January 1, 1976. The city of Frankfurt was chosen as the site ;,c study because (a) narrow, densely built-up areas with high traffic volume were available, and (b) there were few industrial criteriaj meinb that virtually all, tlife airborne lehd was traffic-related and potential for maximum fSKI^ppliv:15'1:.... " Results of air monitoring showed a decline of about 3 0% in general air lead levels as a result of the lead phasedown. In the priffie, the decline' was greater, abcut170%^ However, a decline in traffic density was also noted 'durpLng" tfy! measurement period. The blood lead data is somewhat harder to interpret because of interlaboratory differences in values reported by the three laboratories utilized in the study. (This points out the difficulties in .accurately measuring blood-lead levels.) The decline in blood lead, concentration reported for men ranged from 1,2-1.9 ug/dl,, idependjiiig upon the laboratory. The results for women were more variable} ranging from 0.72-2.75 ug/dl. However, it appears resulted in a decline in bleo<^ IjieaOT ho|'gteWt|rdtion t^f, <Jnly about 10%. This should be taken .as in !-feplSp!5;|::ib|pt' to show whether or Ibl^d; l^ad wa^!' occurring in Frankfurt ^;etrrilear, .such .a'trend was occurring The following important conclusions were reached by the author: o Even though taxi drivers were considered the group most highly exposed to traffic lead, no statistically significant drop in blood lead was noted from 1975 to 1976 in this group. Such a decline was noted .in results reported by 1 of the. 2' laboratories participating in the study from 1976 to 1977, a year after the phasedown. DUP040010915 Ip ETHYI C Q R P <TUE). 5, 1.J90 10:52 HO.28683.14266 PflSE ? --Qj-. o The change in blood lead level due to a change in air lead levels will always be smaller than the theoretical maximum value for long-term exposure. o Relatively high blood lead values would remain even if air lead values were zero. These levels would be about 80-90% of the pre-phasadown levels. The U.K. Department of Environment (DOE) conducted a study to determine the effect of a phasedovn of allowable lead levels in gasoline from-0,4 g/1 to 0.15 g/1 effective January 1, 1986, a reduction of over 60% in gasoline lead (Quinn and Delves, 1579). A total of over 2,000 blood samples were taken each year from 1984-1987, Papulation groups included (1) "exposed," adults living in houses fronting heavily trafficked urban roads, (2) "controls,11 adults living in'areas &ith little exposure to gasoline lead emissions, (3) traffic policemen from several cities, and (4) children living in exposed areas. While the air lead levels declined by about 50% as a result of the phasedovn, blood le^.d levels were much less affected. Blood lead levels f*il by ebcut IC* ir cdults in the year preceding and the year following tnr. pharcJcvr,. in addition, the change in blood lead was the same in the control population as in the exposed population. This rate of decline v-as not nuch different from that noted by the DCE from 157 3 whan they hr.gan monitoring blood lead levels. As groups, boin thr poj:ct-x.fr> er.d children had slightly greater declines the year ^firr chc ;r.'.r.yovr. than the year before. However, it should be nctPd than the ict.i blood leads in both these groups were loweri then i:1. "x^oEPd men" cohort. The DOE concluded that: "Exposure to lead from a number of sources was being reduced simultaneously; bleed lead concentrations probably fell in both 1985 and in 19S6| for reasons '/additional to the reduction in the lead cgntdte: ^lead appeared to have made a slightly larger contribution to. the body burden than for adults." Barltrop (Barltrop et al.r 1989) initiated a similar long-term study to determine the effect of the January 1, 198 6 phasedovn on blood leads. Samples wdre taken in London (urban) and Suffolk (rural) . These areas v^re equivalent to the DOE "exposed" and "control" gtoups. Blood lead was determined in 5 and 6 year old childt^h tfa<p Jj|iiq^'li yeara before and' two years after House dust and drinking water sa*pi:|f: and 3-day dupli^;ate^|p:fit4[||^wlPl^:!|fwfeife^i'!iTVit;e;:* yeat'^tom .^5 mothers end 25 ch^ld^en'.'Majtatii; \Laad ini air,'".road, duet, rainfall and house dust were monitored monthly at defined sites in each :i^scriesfci..'i ';:f" lrpia: Virtually every^ "iiOSpitai during fihis time1 period. DUP040010916 ROM E T H V 1 CHRP 5, I,' 90 iii'3 M0,206a'314266 ?fig u -9 A statistically significant decline in blood lead levels in mother and children occurred right after the phasedown of about 1.5 ug/dl in both London and Suffolk. Before the phasedown, the authors noted a significant decline in blood leads of about l ug/dl between 1983 and 1984 for London children seen in both those years, and a similar rise again in 1984 and 1985. This dip was not significant for London mothers, nor for mothers or children in Suffolk. No significant relationship was found between blood lead and dust lead concentrations in this study. Lead in gasoline declined by over 60* after the phasedown and lead in air values declined by 50% in London in the first year and 40% in Suffolk. The delayed reduction in air lead concentrations observed in s if folk ere thought by the authors to be caused by: retention of stocks of higher 1ad petrol in the rural area into the post pi-asedovn perron; long distance transport of airborne lead from urban :r?'U; crd long-term retention in the atmosphere of a small fracuien of atmospheric read. It is noteworthy that the actual decline in bleed lesci levels in the rural area was about the same as in r.'i urban urea despite, the fact that the air lead decline in the urban area vis about 20 foie. higher than in the rural area. The reason for this was net kr.orn by the investigators, but they suggested tnat routes of exposure other- than direct inhalation of It ad in air might be responsible. Dietary and water intakes of lead were low and essentially equal jr ho4-'- uro?n and rural areas ~r/d appeared to decline during the study period, Tr.e r uv -io; r= r.otcc that the decline in dust lead concentration w?c r,ct ar -c.r/rd or as immediate as the decline in air Ip cc ccn^entr^tions. The/ suggest that some of the decline in blood le=c ' c.rein 15r,5 sr.d 19C6 could be due to a general trend fiemvans resulting from p iodine in dietary intake. The authors stor'd t;jut declaring air Iced concentrations must have had some influence on the decline m blood lead levels since the only consistent decline m bloco lead levels in all groups studied was beev. >n ir9i fid i&6 v r-> lerd in gasoline was reduced 83%. Howe-er, rpgrp.=si 53. ar.aDysr^ o" blood, air, house dust, and dietary da-a indicate that c\c" cf ' he variance can be explained by diet?ry lead _niake, Thus, the study indicates that dietary intake rather ihrn sir I esc or durt 3c'Jfi is the major contributor to blood lead cincentritionc in * ho nether and children studied (Figure 7). The Isotopic Lead Experiment initiated at Turin, Italy in 1974, wlltefa;i:rb4efcnei lead in e^ii|a| l,|i||p|pi!oai!*g. ; Vlded ie4p;|i^ |js:j^hflj;Ip^i!;p4^-b|?eyil!j&if: gasoline laaMIswlibjfllyiE^iSnTOeM -.si; : jraMfq' stable i|||(|i]pj|;:|rj|!iaeji!!j|pipP;it|^ ; Jicauji^j: pfji^iIqii, 'lSediapnb was jpiP!paf|pl||M "Iffeo- ?i^vesp:isgpft|:*^ tfhfi|vfiipipllil|l;lilitlt|f: lli |&ld'iia^gp|p|ip|Ital^Ul1: .p^tirpliit;1 : fctht'flpe1kl^ei^i ijlPiis'Nipnt DUP040010917 SL.. L1L M E T HU COP (THE) .5,. 1/90 18554 110.28:68314266 PAGE 11 1 0 . '- isotopic ratio of 1.04. 'By measuring isotopic ratios of the lead content in various samples, the lower isotopic ratio Broken Hill lead could be traced through the population and the environment. Three groups of subjects from the city of Turin and from the near and far countryside were examined to determine the percentage impact ansi 144 respectively. It is important to note that these results cannot be extrapolated to ether areas of the world without taking into account the following unique conditions in Turin: o the high lead content of gasoline O the very high air lead levels o relative background blood lead levels o the fact that blood leads were higher in the rural areas than in the urban area The content of lead in gasoline in Turin at the time Of the study was 0.6 grams per liter or 2.4 g/gallcn. This compares tc Canadian usage at the same period of time of 1.0 g/gallon, U.S, usage of 1.5 g/gallon and 1.6 g/gallon .in the U.K. Today, the usage levels have been decreased to below o.l g/gallon in these three countries. Thus, the contribution of gasoline lead to blood lead in Turin would be considerably larger than in Canada, the U.S. and the U.K. (Commission of the European Communities, 1983). The air lead levels recorded in the Turin study were all considerably higher' than past and current levels of lead in air in Canada, U.S. and the U.K. Air samples taken at urban .sites in Turin ranged up to approximately 4 to 5 ug/m. Surveys of lead in air in Canadian, American, and British cities rarely exceed 1 ug/a , Blood lead levels in Turin (22 ug/dl)f near countryside (26.9 ug/dl); far countryside (29.6 ug/dl) tend to be considerably higher than those found in the U.S., U.K. and Canada. Also, in contrast to nearly all other studies, blood lead levels of residents of rural areas were higher than in the city of Turin. The data make it apparent that the Turin study reflects a unique situation and one that can only be extrapolated to other areas with extreme caution. Two other studies also showed that gasoline lead was only a minor contributor to blood lead. The ''Dallas Traffic Study" by Johnson (1978) found no relationship between traffic density and blood lead, even though lead in air (ranging from approximately 0.5 ug/m3 to 1.9 ug/nr) was positively correlated with traffic density. Yaffee (1983) used stable isotopic ratios of lead as a tracer. He determined that the blood isotopic ratios of children with moderately elevated blood lead levels1(25 to 43 ug/dl) reflected the isotopic DUP040010918 E7H u e 0RP TO. 5, 1.'50 10:54 118.2500314260 PfiSE 12 -li~ ratios of soil lead to which children were exposed. The soil lead isotopic ratios were very similar to samples contributing to blood lead levels, but. were dissimilar from gasoline lead isotopic ratios, even though the children lived in inner city areas, or close to busy '-freeways*'"1, ' !:7 ' .. ' Some researchers have attempted to relate gasoline lead to blood lead levels in samples collected for other purposes. ^ Billick (1979) used blood lead data from a New York City screening program designed specifically to identify children with to develop a relationship between gasoline lead use and blood lead levels during the period 1971 to 1976. The report focussed on 170,000 records of pediatric blood lead levels in New York and described a fall during 1970-197 6 of about 28% or almost 5% per year along with a concurrent fall in gasoline lead levels. Elwood (1986) has criticized the study because the children in the cohort came from both public and private health providers which were not representative samples of children and nto 1 assurance wa's giv^n|] that the reasons1 ftot1 selection did riot 'v.: " 1 Billick'was also criticized (Ethyl Corporation, 1984) for computing quarterly gasoline lead use for the three states of New York, New Jersey and Connecticut rather than New York City usage and correlating the'figures with quarterly blood lead levels of New York City children,. It| was pointed out that New York City had separate lead In gakpline restrictions, making the lead content of gasoline different in the city than1in the tri-state area. Annest et al. (1983) analyzed a chronological trend in data from the second National Health and Nutrition Examination Survey (NHANE5 II) in 'the United' States which indicated a 37% drop in average blood lead levels', (5.4 ug/dl) from February 1976 through February 1980. The investigators showed that this trend was strongly correlated with a. |ii^j dttfihsithi;s:: period. This :'t|ra;s ipe piybtal point upon which the Environmental Protection! Agency based its reduction of the lead in gasoline standard. A special EPA-appointed review group pointed out several weaknesses in the study, including study design, but noted that "in the absence1of scientifically plausible alternatives" the hypothesis that the drop in blood lead was caused by the drop in gasoline lead "must receive serious consideration." other criticisms (DuPont 1984; x|:^4;|j'i ;bla.|i0d:| takrerfoi. Othbr errors in the analysis as well as inconsistencies in the data set. These include the fact that the cohort continually changed from a demographic - standpoint lover the four years of the study. One of the strongest 5|Met' iafLi. tot "into account otter'"gpneufre^t'actions*!lw0ich:ty0tf*11'hayc1''''redubiid blood lead levels tov^r1' 0? DUP040010919 (Hit) 5.. L'90 18:53 HO.;20693i4266 PAGE 13 12 '- *Therefore, while blood lead levels have declined over at least the past decade, these declines seem to have been for the most part, unrelated in a significant way to lead in gasoline usage- Other controls, such as on the Ifead content of food, have apparently been quite effective in reducing population blood lead levels. DUP040010920