(,1 2 1/,1(...rules for the development of State im-plementation ' plans promulgated under 40 CFR Part 51, and an advance notice of proposed rulemaking under 40 CFR Part 51 for ambient

Citation: 43 Fed. Reg. 46246 1978

Content downloaded/printed from HeinOnline (http://heinonline.org)Thu Mar 10 14:54:22 2016

-- Your use of this HeinOnline PDF indicates your acceptance of HeinOnline's Terms and Conditions of the license agreement available at http://heinonline.org/HOL/License

-- The search text of this PDF is generated from uncorrected OCR text.

46246

[6560-611Title '40-Protection of Environment.

CHAPTER I-ENVIRONMENTALPROTECTION AGENCY

SUBCHAPTER C-AIR PROGRAMS

[FRL 937-5]

PART 50-NATIONAL TARIMARY ANDSECONDARY AMBIENT AIR -QUAL-ITY STANDARDS

National Primary and -Secondary Am-bient Air Quality Standards -forLead

AGENCY: Environmental ProtectionAgency.ACTION: Final rulemaking.SUMMAY:--PA is setting a nationalambient air quality.-standard for leadat a level of 1.5 micrograms lead percubic meter of air .(g Pb/n), aver-aged over a calendar quarter. Thisfinal rulemaking follows a 1976 courtorder to list lead as-a criteriaipollutantfor the development of an ambientstandard, and the Agency's issuance ofa proposed standard on December 14,1977. In response to comments re-ceived on the proposed standard, EPAhas changed the averaging period forthe standard from a calendar monthto a calendar quarter, and has clarifiedthe health basis used in selecting thestandard level.

In establishing the level of the finalstandard, EPA has determined thatyoung children" (age 1-5 years) shouldbe regarded as a group within the gen-eral population that is particularlysensitive to lead 'exposure. The finalstandard for lead in air is -based onpreventing most children in theUnited States from exceeding a bloodlead level of 30 micrograms lead perdeciliter of blood (gg Pb/dl). Bloodlead 1evels above 30 -±g Pb/dl Are asso-ciated with the impairment of hemesynthesis in cells indicatedby elevatederythrocyte protoporphyrin '(EP),which EPA xegards Ls adverse to thehealth of. chronically exposed chil-dren. There are a number of-other-ad-verse health effects associated Withblood lead levels above 30 gg Pb/dl, inchildren as well as in the general pop-ulation, including-the possibility thatnervous system damage may occur inchildren even without overt-symptomsof lead poisoning.DATES: Effective: October 5; 1978.After promulgation, States will havenine months (until July 5, 1979), toprepare and submit to EPA plans forattainment of the standard by no laterthan October of 1982. EPA's final reg-ulations for the development of State

-RULES AND REGULATIONS

implementation plans appear else-where in this FEDERAL REGISTER.

FOR FURTHER INFORMATIONCONTACT:

Mr. Joseph Padgett, Director, Strat-egies and Air Standards Division,Office of Air Quality Planning andStandards, U.S. Environmental IPro-tection Agency, Research TrianglePark, N.C. 27711, telephone 919-541-5204.

AVAILABILITY OF RELATED INFORMATION

A docket (No. OAQPS-77-1) contain-,ing the information used by EPA inthe development of the proposed=standard isaVailable for public inspee-tiori and copying between 8 a.m. arid4:30 p.m., Monday through Friday, atEPA's Central Docket Section, Room2903B, Waterside Mall, 401 M StreetSW., Washington, D.C. 20460.

The Federal reference method forcollecting and. measuring lead and itscompounds in the ambient air is pub-lished ii appendix G to this promulga-tion. This FEDERAL REGISTER also cofl-tains proposed regulations under 40CFR Parts '51 and 53 for equivalentlead air monitoring methods, finalrules for the development of State im-plementation ' plans promulgatedunder 40 CFR Part 51, and an advancenotice of proposed rulemaking under40 CFR Part 51 for ambient monitor-ing in the vicinity of certain industrialplants with lead emissions. Additionalinformation for the development ofthe State implementation plans is con-tained in the document Supplemen-tary Guidelines for Lead Implementa-tion Plans. The environmental andeconomic impacts of implementingthis standard are described in an envi-ronmental impact statement and aneconomic impact assessment. -Thesedocuments are avdilable for public in-spection and copying at the CentralDocket Section (address above). Copiesmay be obtalmed upon request fromMr. Joseph Padgett at the above ad--dress.

The documents Air Quality Criteria-for Lead and Control Techniques forLead Air Enissions were issued af' the-time of -proposal. The Control Tech-

- niques Document is available upon re-quest from Mr. Joseph Padgett at theabove address. The Air Quality Crite-ria Document can be obtained from:Mr. Michael Berry, Environmental,Criteria and -Assessment Office, MD-52," Office of Research and Develop-ment, U.S. Environmental ProtectionAgency, Research Triangle Park, N.C.27711, telephone 919-541-2266.SUPPLEMENTARY INFORMATION:

BACKGROUND

Lead is emitted to the atmosphereby vehicles burning leaded fuel and-bycertain stationary sources. Lead enters

the human body through Ingestionand inhalation with consequent absorption into the bloodstream and dis-tribution to all body tissues. Clinical,epidemiological, and toxicologicalstudies have demonstrated that expo-sure to lead adversely affects humanhealth.

EPA's initial approach to controllinglead in the air was to limit the leademissions from automobiles, the prin--cipal.source of lead air emissions. Reg-ulations for the phasedown of lead inthe total-gasoline pool were promul-gated In 1973, and, following litigation,modified and put into effect in 1976,The Agency has also established regu-lations requiring th'e availability of no-lead gasoline for catalyst-equippedcars. EPA also intended to controlemissions from certain categories ofindustrial point sources under sectionill of the Clean Air Act.

In 1975, the Natural Resources De-fense Council (NRDC) and othersbrought suit against EPA to list leadunder section 108 of the Clean Air Actas a pollutant for which air quality cri-teria would be developed and a nation.al ambient air quality standard estab.lished under section 109 of the Act.The Court ruled In favor of NRDC.(NRDC, Inc. et aL v. Train, 411 F.Supp. 864 (S.D.N.Y., 1976) aff'd 545 1.2d,320 (2d Cir. 1976).) EPA listed leadon March 31, 1976, and proceeded todevelop air quality criteria and theproposed standard.

On December 14, 1977, EPA pro-posed a standard of 1.5 jtg Pb/m, cal-endar month average,, proposed theFederal reference method for monitor-ing air lead levels, issued the docu-ments Air Quality Criteria for Leadand Control Techniques for Lead AirEmissions and proposed regulationsfor State implementation plans, EPA'invited public comments during theperiod from December 14, 1977, toMarch 17, 1978, on the standard, refer-ence method, and the SIP regulations,Additional comments on these matterswere provided to EPA at a public hear-ing held on February 15-16, 1978.

LEGISLATIvE REQUIREMENTS For NA-TIONAL AMBIENT AIR QUALITY STAND-ARDSSections 108 and 109 of the Clean

Air Act govern the development of na-tional ambient air quality standards.Section 108 Instructs EPA to docu-ment the scientific basI9 for the stand-ard:

Section 108(a)(2). The Administrator shallissue air quality criteria for an air pollutantwithin 12 months after he has included suchpollutant in a list under paragraph (1). Airquality criteria for an air pollutant shall ac.curately reflect the latest scientific knowl.edge useful in indicating the kind andextent of all Identifiable effects on publichealth-or welfare which may be expectedfrom the presence of such pollutant in the

FEDERAL REGISTERe VOL 43, NO. 194-THURSDAY, OCTOBER 5, 1978

ambient air, in varying quantities. The crite-ria for an air pollutant; to the extent practi-cable, shall include information on- '

(A) Those variable factors (including at-mospheric conditions) which of themselvesor in combination witth other factors mayalter the effects on public health or welfareof such air pollutant;

(B) The types of air pollutants which,when present in the atmosphere, may inter-act with such pollutant to, produce an ad-verse effect on public health or welfare; and

(C) Any known or anticipated adverse ef-fects on welfare.

Section 109 addresses the actual set-ting of the standard:

Section 109(b)(1). National primary ambi-ent air quality standards, prescribed undersubsection (a) shall be ambient air-qualitystandards the attainment and maintenanceof which in the judgment of the Adminis-trator, based on such criteria and allowingan adequate margin of safety, are requisiteto protect the public health. Such primarystandards may be Tevised in the samemanner as promulgated. .

(2) Any national secondary ambient airquality standard prescribed, under subsec-tion (a) shall specify a leVel of air qualitythe attainment-and maintenance of whichin the judgment of the Administrator, basedon such criteria, is requisite to protect thepublic welfare from any known or anticipat-ed adverse effects associated with the pres-ence of such air pollutant in the ambientair. Such secondary standards may be re-vised in the same manner as promulgated.

In order to conform to the require-ments of section 109, EPA has basedthe level of the lead air quality stand-ard on information presented in thecriteria document pertaining to thehealth and welfare implications oflead air pollution. This is in contrastto other sections of the Act underwhich EPA considers economic costsand technical availability of air pollu-tion control systems in determiningemissions limitations. It is clear fromsection 109 that the Agency shouldnot attempt to place the standard at ,level estimated to be at the thresholdfor adverse health effects, but shouldset the standard at a lower level inorder to provide a margin of safety.EPA believes that the extent of themargin of safety represents a judg-ment in which the Agency considersthe severity of reported health effects,the probability that such effects mayoccur, and uncertainties as to the fullbiological significance of exposure tolead.I Comments resulting from externalreview of the air quality criteria andthe proposedstandard highlight dis-agreements on a number of areas criti-cal to EPA's rationale for the stand-ard. However, the scientific data baseprovided in the document Air QualityCriteria for Lead is as extensive asthat for any other regulated air pol-lutant. Also, at every stage of develop-ment of the air quality criteria andthe standard, EPA has facilitated andreceived broad eiternal participation.

RULES AND REGULATIONS

EPA regards as inevitable the presenceof scientific disagreement and uncer-tainty about key factors relevant toenvironmental standards. Provisionsof the Act requiring timely promulga-tion of the standard, and requirementsfor periodic future review of air qual-ity criteria and standards indicate con-gressional intent that the Agency pro-ceed even where scientific knowledgeis not complete or full scientific con-sensus is absent.

SUMTARY OF GENERAL FmDinGs F!RouAm QUALITY CRITERIA FOR Lvw

Following the listing of lead as a cr-teria pollutant, EPA developed thedocument, Air Quality Criteria forLead. In the preparation of this docu-ment. EPA provided opportunities forexternal review and comment on threesuccessive drafts. The document wasreviewed at three meetings of the Sub-committee on Scientific Criteria forEnvironmental Lead of EPA's ScienceAdvisory Board. Each of these meet-ings was open to the public and anumber of individuals presented bothcritical review and new informationfor EPA's consideration. The final cri-teria document was issued on Decem-ber 14, 1977.

From the scientific information inthe criteria document. EPA draws con-clusions in several key areas with par-ticular relevance for the ambient airquality standard for lead.

1. There are multiple sources of leadexposure. In addition to air lead, thesesources include: Lead In paint and ink,lead in drinking water, lead in pesti-cides, and lead in fresh and processedfood.

2. Exposure to air lead can occur di-rectly by inhalation, or indirectly byingestion of lead contaminated food,water, or nonfood materials includingdust and soil.

3. There is significant individualvariability in response to lead expo-sure. Even within a particular popula-tion, individual response to lead expo-sure may vary widely from the averageresponse for the same group. Certainsubgroups within the general popula-tion are more susceptible to the ef-fects of lead or have greater exposurepotential. Of these, young childrenrepresent a population of forbmostconcern.

4. Three systems within the humanbody appear to be most sensitive tothe effects of lead-the blood-formingor hematopoietic system, the nervoussystem, and'the renal system. In addi-tion, lead has been shown to affect thenormal functions of the reproductive,endocrine, hepatic, cardiovascular, im-munologic, and gastrointestinal sys-tems.

5.'The blood lead level thresholdsfor various biologic effects range fromthe risk of permanent, severe, neuro-

46247

logical damage or death as blood leadsapproach and exceed 80 to 100 pg Pb/dl in children down to the inhibitionof an enzymes system as low as 10 pgPb/dl.

6. Lead is a stable compound, ubiqui-tously distributed, which persists andaccumulates both in the environmentand in the human body. In developingthe proposed standard. EPA usedthese findings to arrive at a standardlevel of 1.5 pg Pb/m3, calendar monthaverage. This level was derived fromthe Agency's judgment that the maxi-mum safe blood lead level (geometricmean) for a population of young- chil-dren was 15 pg Pb/dl and, of thisamount. 12 pg.Pb/dl should be attrib-uted to nonair sources. The differenceof 3.0 pg Pb/dl was estimated to be theallowable safe contribution to meanpopulation blood lead from lead in theair. With epidemiological data indicat-ing a general relationship of 1:2 be-tween air lead (pg Pb/m3) and bloodlead (pg Pb/dl), EPA determined thatthe level for the proposed standardshould be 1.5 pg/l 3.

SummARY OF ANcTIPATED IMPACTS

While the level of the standard isbased on health considerations, EPAhas conducted econoffic and environ-mental studies to assess the potentialimpacts of the standard selected. EPAestimates that the existing regulationsfor the phase-down of lead in gasoline,combined with the increasing use ofno-lead gasoline for catalyst-equippedcars, will result in attainment of thestandard in urban areas where auto-mobile exhaust is the dominant sourceof air lead. No additional pollutioncontrols are anticipated for theseareas.

EPA's economic analysis does indi-cate that there may be significantproblems in attainment of the stand-ard in the vicinity of nonferrous smelt-ers and other large industrial sourcesof lead emissions. This assessment isbased, however, on studies using gen-eral emission factors and plant con-figurations, combined with dispersionmodeling. In the development of Stateplans to-implement the standard, EPAis encouraging affected industries andState agencies to gathe plant-specifictechnical data, ambient air qualitydata, and assessments of alternativeengineering controls. With this infor-mation, the Agency will be able tomore accurately evaluate the impactof the standard .and better considerapproval of alternative approaches toemission control in the State plans.

Also, EPA is encouraging affectedfirms and State agencies to evaluate inthe early design phase, strategieswhich take into consideration theworkplace standard for airborne leadwhich will be promulgated by the Oc-cupational Health and Safety Admin-

FEDERAL REGISTER, VOL 43, NO. 194-THURSDAY, OCTOBER 5, 1978

46248

istration (OSHA). EPA believes thatthis :approach will facilitate applica-tion of control technologies whichmeet the requirements of both agen-cies. In working-with OSHA to esti-mate the combined. impact of theOSHA and EPA standards,'in coordi-nating compliance strategies, and inreviewing State plans implementingthe ambient standard, EPA intends toavoid an approach which would fosteruncertainty in the investment dei-sionsoof affected firms.

The Agency will make every effort'to insure that all opportunities toavoid plant closures are exam ined,while at the same time 'assuring pro-tection from clear risks to the publichealth.

SuMARY. oF CoMNTs RECEIVED

During the comment period fromflecember 14, 1977, to March 17, 1978,and at the public meeting on February15-16, 1978, -EPA received 95 writtenand oral comments addressing the pro-posed standard or -the requirementsfor State implementation plans. Allcomments opposing 'the -standard asexcessively stringent (25) came from-xepresentatives of affected industries,and 20 of these counter-proposed 5.0ttg Pb/m, calendar quarter average, asthe appropriate level for the standard.

Comments ,Received .Opposing the Proposedstandard of 1.5 lig/m' Calendar ,MonthAverage asExcessively Stringent

Company Op- En-posed ' dorsed 2

AmaxLead &Zinc, . X , XAmerican Mining Congress ......... x MAmerican Petroleum Institute . XASARCO ............................................ XAssociated Octel Co., Ltd X XBattery Councl InternationaL.... - - XBethlehen.Steel Corp ........ .. .Bunker Hill Co. ............... * ............. X XC & D_ Batterles vslon-o.......... x 7XE. L du Pont de Nemours & Co.,

Inc .............. . ................ .. x XESA Laboratories, Inc ..................... X XEthyl Corp .................................. X xGeneral Battery,Cor rp........... X XGeneral Motors.Corp-...............Getty Refining & Marketing Co XHECLA Mining Co ........................... xHouston:Chemlcal .................. .X NHunt Oil C o. NKerr-M cKee Corp ..........................................Lead Industries Association ........... x X'Nalco 'Chemical :X XN L Industries,'In n. ....... x XPrestolite BatteryDivision..... X XSecondary Lead Smelters Associ-

ation . ............................ x XShell Oil Co .............. -..... ..... xSt. Joe Minerals Cor-.._...-.. X XTexaco. Inc ........ ................. ............. x XUnited Machinery Group., ..................Vulcan Materials Co .............

'1.5 jg/rm, calendar month.•. 5.0 pg/mr' calendar quarter (or other averaging

period).Sueny: Forty-five comments received from 29

corporations or their representatives; 25 of the 29firms opposed the proposed standard of 1.5 pg/m'calendar month -average; 20 endorsed an alternative


standard'of-5.0 jg/nil. calendar.quarter-average (orother averaging period).

Four comments 'opposed the pro-posed standard on the grounds that it,was -not sufficiently protective .ofhealth.

CoMMNrs RECEIVED OPPosno PROPOSEDLEAD AIR 'QUAiITY STANDARD OF 1.5 gg/m3 ,

-CALENDAR MONTH AVERAGE, IN .FAVOR OF AMOR STRINGENT~ STANDARD,,

Natural Resources Defense CouncilDr. Sergio Piomelli, Director;, Pediatric- Ie-

matology, -New -York -University MedicalCenter Public Interest Campaign

University of Connecticut School of Med,cine

- Comments suppoiting the level ofthe proposed standard (17) came fromthe medical community, Federal agen-cies, State :and local public health'agenciesand public interest-groups.

COMMENTS -REcExvED ENDORSING PROPOSEDIYAn AIR QUALIrY STANmaR OF 1.5 Ag/m*,CALENDAR MoNTa AVERAGE

-STATE AND LOCAL 'AGENCIES

California Department of HealthWassachusetts Department of Public'HealthNew York State Department of ,Environ-

- mental ConservationNew York City Department of Environmen-

talProtectionTennessee Department of-Public Health'Wisconsin 'Department of 'Natural Re-

sources

FEDERAL AGENCIESCenter -for Disease 'Control, Public Health

ServiceDepartmenlt of Transportation-Food and Drug AdministrationOccupational Safety and Health Adminis-

tratiofi-'

PUBrc INTEREST'GROUPS AND THE MEDICAL

"Comritte -on Environmental Hazards,American Academy of Pediatrics

D.C. Committee for Lead Elimination in theDistrict

League of Women Voters of the lUnitedStates

National UrbanLeague.Herbert 'Needleman, :Boston Children's Hos-

pital Medical CenterUniversity of' North Carolina 'School of

Public Health

In .addition, -EPA has received- nu-merous comments and correspondenceon the proposed standard after the of-ficial end of the comment period.Though 'EPA-does not have a legal ob-ligation to review these documents, -ithas, in the interest of fostering full

-public participation in the rulemakingprocess, reviewed these comments andcorrespondence as time permitted. Aswith all other documents considered

_or examined by EPA as part of its de-cision process, these documents havebeen placed in the public .docket andhave become part of the administra-tive record of this decision.

The comments received by EPA did,not challenge three -aspects of the pro-posed standard:

1. The basic structure of the rdtio-nale used by the Agency .in derivingthe level of theproposed standard.

2. The selection of young children asa population particularly at risk tolead exposure.

3. The attribution of 12 1Ag Pb/dl outof the target mean population blood

-lead level of 15 ig Pb/dl to nonairsources of lead for the purposes of set-ting the air standard.

Significant comments vere received,however, on the following key areasrelating to the standard:

1. The elevation of erythrocyte pro-toporphyrin (EP) as the first adversehealth effect with increasing lead ex-posure rather than the decline of he-•mogl6bin levels.

2. The blood lead threshold level forelevated EP.

3. The incidence of health effects Inpopulations residing in the vicinity of• industrial sources of lead particulateemissions.

4. The relationship describing the re-sponse of lead In the blood to lead inthe air.

5. The statistical form and averagingperiod for the standard.

6. The appropriate marginof safety.7. The limitation of the standard to

the respirable fraction of total air leadparticles.

8. The economic Inpact of the stand-ard.9. The State implementation planregulations.10. The Federal reference method

formonitoring lead air quality.11. The administrative procedures

employed by EPA in the; developmentof the standard and wthe provision forpublic participation.

A review of the comments receivedand their disposition has been placedin the rulemaking docket (OAQPS-77-1) ifor public -inspection., The following,paragraphs summarize the significantcomments and present the Agency'sfindings.

THE HEALTH SIGNIFICANCE OF ERYTHRO-CYTE PROTOPORPHYIIN ELEVATION

Ten commenters disagreed with-EPA's conclusion -that 'the impairmentof heme synthesis indicated by elevat-ed erythrocyte protoporphyrln (EP)constituted an adverse health effect.Reasons for this disagreement inelud-ed:

1. An elevated level of EP is notitself 'toxic to the cells in blood or,other tissues.

2. 'EP elevation, -while indicating achange in heme synthesis, does not in.

"-dicate an insufficient production ofheme, or hemoglobin.

3. 'EP elevation and the alteration Qfheme synthesis does not imply impair-

.FEDERAL REGISTER, VOL .43, NO. 194-THURSDAY, -OCTOBER '5, 1978


ment of other mitochondrialtions.

4- EP elevation is not associatedimpairment of other heme proparticularly cytochrome P-450.

5. Elevated EP may be causeconditions other than exposurlead, particularly iron deficiency.

Five commenters agreed with Iconclusions about the health sicance of elevated EP citing the fting arguments:

1. The interference of lead in adamental cellular metabolic funto the extent that there is acettion of a substrate is physiologicpairment, even without the preof clinical evidence of disease.

2. It is prudent medical practiintervene where subclinrcal indicof physiological impairment areent.

3. The impairment of heme sysis resulting from genetic or difactors places a child at enhancecto lead exposure.

4. There is evidence to suggestimpaired heme synthesis may -the function of neural or hetissue even at levels where hemeduction is sufficient for hematopc

AGENCY RESPONSE

EPA agrees with the commenIceived that the -initial elevation cas a result of exposure to lead,indicating an impairment of hem(thesis, may not be a disease stateseen as a clinically detectable d(in performance. However, the crdocument points out (p. 1-13) thaimpairment does-increase progrely with lead dose.

-The hematological effects describedare the eariesf physiological impairencountered as a function of ncreasinexposures as indexed by blood leadtions, as such, those effects may be cered to represent critical effects of le,posure. Although it may be argued ti-tain of the initial hematological ((such as ALAD inhibition) constitutetively mild, nondebilitating symptoilow blood lead levels, they nevertsignal the onset of steadily intensifytverse effects as blood lead elivatio:crease- Eventually. the hematologicfects reach such magnitude that theyclear-cut medical .significance as Indiof undue lead exposure.

The fact that other conditions,as iron deficiency may also iiheme synthesis, does not obviatecem that lead is interfering witessential- biological function. Thtthe possibility that a nutritionalciency is an additional stress t(heme synthetic system which mEcrease the sensitivity of a child tadverse effects of lead exposure.

EPA notes that there -is geagreement that heme and hemctaining proteins play importantin the oxygen fixation pathways

fune-- cells. While the effects of low-levellead exposure on the heme synthetic

with pathway in erYthrold tissue have beenteins. extensively studied in part because of

the ease with which this tissue may bed by obtained, other cellular metabolic-sys-re to tems utilizing heme are less well un-

derstood. EPA does not have sufficientPA's information to conclude that impair-

gnifi- ment of heme synthesis In other tis-llow- sues is not of concern until blood lead

levels are reached greater than thosefun- associated with hematological effects.

rction The air quality criteria document doesnula- point out that this effect has been es-a im- tablished in other tissues and thatsence other dose-response factors may apply.

The effect of lead on the formation ofce to -heme Is not limited to the hematopbleticators system. Experimental animal studies havepres- shown a lead effect on the heme-requiring

protein, cytochrome P-450. an integral partnthe- of the hepatic mixed-function oxIdaseetary (chapter 11). the systemic function of which

risk Is detoxification of exogenous substances.Heme synthesis inhibitionm also takes place

that in neural tLmue. CP. 13-5.)Lffect In summary, the criteria documentpatic states:pro- Elevation In protoporphyrinis considered

)iesIS. not only to be a biological Indicator of Im-paired InItochondrlal function of erythroldtissue bit also an Indicator of accumulationof substrate for the enzyme ferrochelatase.It therefore has the same pathophysologi-

of EP 6al meaning as increased urinary 8-ALAwhile (vide supra). For these reasons, accumula-e syn- tion of protoporphyrln has been taken to In-or be dicate physiologieal Impairment In humans.!cline and this clinical consensus Is expressed Initeria the 1975 Statement of the Center for Dis-t this ease Control (CDC), USPHS. The criterion

used by CDC to Indicate an effect of lead onssive- heme function Is an FEP level of 60 pg/dl Inthe presence of a blood lead level above 30

above pg/dl whole blood.rments More recent Information relating tog lead threshold of lead effects Indicates that PEPeleva- levels begin to increase at a blood lead valueonsld- of 15 to 20 pg Pb/dl blood In children andad ex- women and, at a somewhat higher value. 20itcer- to 25 pg Pb/dl blood, In adult men. (P. 13-5.)ffects EPA concludes that the state of ele-

rela- vated EP must be regarded as poten-ms at

heless tially adverse to the health of young,g.ad- children. While the onset or a mild ex-ns in- perience of this condition may be tol-al ef- erated by an individual, as with otherare of subclinical manifestations of Impairedcatom function. it is a prudent public health

practice to exercise corrective actionsuch prior to the appearance of clinicalapair symptoms. The criteria document re-con- ports that symptoms of anemia in chit-

th an dren may occur at blood lead levels of!re is 40 pg/d. EPA has adopted 30 pg Pb/dldefi- as a maximum safe blood lead level forthe individual children.

Ly Mh THE BLOOD LEAD THRESHOLD FOR ELEVAT-Sthe E ERYTHROCYTE PROTOPORPHYRIN

neral Comments provided by ten organiza-"-con- tions challenged EPA's conclusionroles that the threshold for the elevation ofin all EP occurs in children at a blood lead

level of 15 pg/dL Evidence offered for.a higher threshold included:

1. The threshold accepted by EPA isbased on a study in which an inappro-priate statistical technique, probitanalysis, was employed.

2. Application of a more appropriatetechnique, segmented line analysis, re-sults in a higher threshold.

3. The study in" question excludeddata on children with blo6d lead Ievqlsin excess of 30 pg/d.

4. Other investigators have reportedhigher thresholds.

Comments in support of the 15 pg/dlthreshold maintained:

1. It Is proper to exclude values con-sidered abnormal if the intent of theanalysis is to determine an unbiasedeffect threshold.

2. Other studies have reportedthresholds with error bands which in-clude 15 pg/dl.

3. Probit analysis Is an appropriatetechnique and differs only slightlyfrom the results 6btained from seg-mented line analysis.

AGENCY RESPONSE

EPA agrees that the segmented linetechnique provides a more accurate es-timate of the correlation threshold ofEP elevation with increasing bloodlead, about 16.7 pg PbldL and for thisreason considered changing its judg-ments as to the maximum safe bloodlead level for a population of children.However, as the target geometricmean for a population is increased, agreater percentage of children in thepopulation will exceed the maximumsafe individual level of 30 pg PbfdLEPA estimates that at a populationgeometric mean of 15 pg Pb/d. 99.5percent of children will be below 30 pgPb/dL At 16.7 pg Pb this percentagefalls to 98.7. EPA regards the numberof children predicted to be below 30 pgPb/dl as the critical health considera-tion. For this reason, EPA has main-tained its estimate of a geometricmean of 15 pg Pb/dl as the target fbrpopulation blood lead.

THE INCIDENCE OF HEALTH EFFECTS IlfPOPULATIONS RESIDInG Inr THE VICfl=-TY OF INDUSTRIAL SOURCES OF LEADPARTICULATE EKSSIONS

Several comments cited situations inwhich proximity to significant pointsources of airborne lead emissionsappear to have little or no healthimpact on resident populations. Thiswas taken to imply that the air stand-ard was not necessary to protect publichealth.

AGENCY RESPONSE

EPA aclmowledges the variability ofthe impact of exposure to air lead onthe potential for adverse health conse-quences. It is clear that direct expo-sure to air lead is only one of the


46249

46250

routes through which human expo-sure occurs. It is for this reason thatthe Agency has accepted the conceptthat only a portion of the safe popula-tion mean blood lead level should beattributable to air lead exposure. Thepresence or absence of health effectsin an exposed population is influencedby a variety of factoks including:,Me-teorology, terrain ,characteristics, geo-lodical and anthropological history,pdrsonal and domestic hygiene, the oc-cupations of the population members,,and the food and nonfood materialswith which they come into contact.Taking into account such variability, itremains the Agency's belief that air-borne lead directly and indirectly con-

, tributes to the risk of adverse healthconsequences and that sufficient clini-cal and epidemiological evidence isavailable to form a judgment as to theextent of this contribution. This evi-dence Includes epidemiological studiesshowing higher blood lead levels inurban areas where air lead levels wereelevated in comparison to rural areas.There have also been a number of.studies linking elevated blood leadlevels -to industrial sources of leademissions. With regard to the 1972tudy at El Paso, Tex., by the Center

for Disease Control, the criteria docu-ment reports:

It was concluded that the primary factorassociated with elevated blood lead levels inthe children was ingestion or inhalation ofdust containing lead. Data on dietary intakeof lead were not obtained because the cli-mate and proximity to the smelter prevent-ed any farming in the area. It was unlikelythat the dietary lead intakes of the childrenfrom near the smelter, and farther awaywere significantly different. (P. 12-15.)

With regard to the report of Yankelet al. at Kellogg, Idaho, the criteriadocument states:

Five factors influenced, In a statisticallysignificant manner, the probability of achild developing an excessive blood leadlevel:

1. Concentrations of lead in ambient air

2. Concentration of lead in soil (ppm).3. Age (years).4. Cleanliness of the home (subjective

evaluation.coded 0, 1, and 2, with 2'signify-ing dirtiest).

5. General classification of the parents'occupation (dimensionless).

Although the strongest correlation foundwas between blood lead levels and air leadlevel, the authors concluded that it was un-likely that inhalation of contaminated airalone could explain the elevated blood leadlevels observed. (P. 12-16.)

THE APPROPRIATE RELATIONSHIPBETWEEN LEAD IN AIR AND LEAD IN BLOOD

Several commenters questioned. theAgency's estimate that, for children,one microgram of lead per cubic meterair (g Pb/m results in an increase of


two micrograms lead per deciliterblood (jIg Pb/dl).

AGENCY RESPONSE

EPA has reviewed the studies dis-cussed in the criteria document whichreport changes in blood lead levelswith different air lead levels. TheAgency. believes that one of thestrongest epidemiological studies isthat by Azar et al. in.which personaldosimeters were used to measure leadintake. This eliminated some of theuncertainty about the extent to whichair quality observations accurately re-flect actual exposure. From the Azardata, the relationship of lead in the air.to lead in the-blood, evaluated at 1.5jig Pb/ma was 1:1.8. The Azar studywas,-however, limited to an adult pop-'ulation.

A clinical study of adults, Griffin etal., gives roughly the same conclusionfor a group of adults confined to achamber with controlled exposure tolead aerosol. This study was conductedover a three month period with con-trol over lead ingestion. As air- leadlevels n the chamber were increasedfrom 0.15 ji Pb/m3 to 3.2 jig Pb/m3,the air lead to blood lead relationshipwas 1:1.7.

Because children are known to havegreater net absorption and retentionof lead.than adults, it is reasonable toassume that the air lead to blood leadrelationship for this sensitive popula-tion, exposed to air lead levels in therange of the proposed standard, isequal to if not greater than for adults.EPA also notes that the air lead toblood lead relationship is nonlinearand may result in a higher ratio atlower air levels.

In an epidemiological study of chil-dren near a smelter, Yankel et al., theresponse of blood lead to air lead, av-eraged over :the exposure range, was1.9. EPA believes that these studies aswell as others reported in the criteriadocument, support the criteria docu-ment's conclusion that:

Ratios between blood lead levels and airlead exposures were shown to range general-ly from 1:1 to 2:1. These were not, however,constant over the range or air lead concen-trations encountered. There are suggestivedata indicating that the ratios for childrenare in the upper end of the range and mayeven be slightly above it. There is also someslight suggestion that the ratios for malesare higher than those for females. (P. 12-38.) -

THE STATISTICAL FORM AND PERIOD OFTHE STANDARD

One commenter expressed the viewthat, due to the lognormal distributionof measured air lead, a not-to-be-ex-ceeded standard of 1.5 jg/m3, calendarmonth average, would require sourcesof air lead to achieve control of theiremissions to a geometric monthlymean of 0.41 jg/M3 in order to prevent

the occurrence of a violation. Anothercomment expressed the opinion that,with the normal operation of a 6-day,sampling schedule, the number ofsamples which could be collected Inthe course of a calendar month wouldnot provide a statistically valid esti-mate of the actual lead air quality forthe period.'

Several comments questioned thehealth basis for the selection of thecalendar month averaging period.

EPA RESPONSE

EPA accepts the consensus of com-ments received on the scientific andtechnical difficulties presented by theselectibn of a calendar month averag-ing period. The Agency believes thatthe key criterion for the averagingperiod Is the protection of health ofthe sensitive population. In proposingthe 1.5 1ig/m 3 standard, EPA conclud-ed that this air level as a ceiling wouldbe safe for indefinite exposure ofyoung children. The critical questionin the determination of the averagingperiod is the health significance ofpossible elevations of air lead ,above1.5 jg/m3 which could be sustainedwithout violation of the average of 1.5pg/m 3. In the proposed standard, EPAchose a monthly averaging period onthe basis of a study showing an adjust-ment period of blood lead level with achange of exposure (Griffin et al.). Be-cause of the scientific and technicaldifficulties of the monthly standard,EPA has reexamined this question andconcludes that there Is little reason toexpect that the slightly greater possi-bility of elevated air lead levels withinthe quarterly period is significant forhealth. This conclusion Is based on thefollowing points:

(1) From actual ambient measure-ments, the distribution of air leadlevels is such that where the quarterlystandard is achieved, there Is littlepossibility that there could be sus-tained periods greatly above the aver-age value.

(2) While It is difficult to relate theextent to which a monitoring networkactually represents the exposure situa-tion for young children, it seems likelythat where elevated air lead levels dooccur, they will be close to point ofmobile sources of lead air pollution.Typically, young children will not en-counter such levels for the full 24-hour period reported by the monitor.

(3) There is medical evidence indi-cating that blood lead levels recqulli.brate slowly to changes in air expo-sure. This serves to dampen theimpact of a short-term period of expo-sure to elevated air lead.

(4) Direct exposure to air is only oneof several routes of total exposure.This lessens the Impact of a change inair lead on blood leid levels.

FEDERAL REGISTER, VOL 43, NO, 194-THURSDAY, OCTOBER 5, 1978

On balance, the Agency concludesthat a requirement for the averagingof air quality data over calendar quar-ter -will improve the validity of airquality data gathered without a sig-nificant reduction in the protective-ness of the standard.

THE APPROPRIATE MARGIN OF SAFETY

Several comments received by theAgency criticized the proposed stand-ard for incorporating an excessivemargin of safety. This. criticism wasbased either on the view that the criti-cal health effect,, impaired heme syn-thesis, was not of health significanceor on the view that, EPA had employedconservative, estimates of the several-factors used in calculating the stand-ard which, when combined, resulted inan excessively stringent standard.

Other comments were receivedwhich expressed concern that thestandard had little or no margin ofsafety, particularly for certain sub-groups within the general populationof young children.

AGENCY RESPONSE

EPA does not agree that the impair-ment of heme synthesis is a physio-logical response to lead exposure thatis without health significance. WhileEPA does not fid- that this impair-ment is necessarily serious to. health atthe point at which it first can be de-tected by the elevation of erythrocytaprotoporlphyrin, at a threshold in arange of 15-20 pg Pb/di, the Agencydoes believe that above blood levels of30 pg Pb/dl this effect has progressedto the extent that it should be regard-ed as an adverse health effect.

In determining the final ambient airstandard' for lead, EPA has usedmargin of safety considerations princl-pally in establishing a maximum safeblood lead level for individual childrenat 30 jg Pb/dl and in determining the-percentage of children to be placedbelow this maximum level, about 99.5percent. Usini these factors, results ina target geometric niean populationblood lead of 15 pg Pbfdl.

In establishing other factorsused incalculating the standard, EPA hasused margin of safety in the sense ofmaking careful judgments based on-available data, but these judgmentshave not been at the precautionary ex-treme of the range of data available tothe Agency. In the case of the geomet-ric standard deviation (GSD), studiesreviewed in the criteria documentshowed a range of 1.3 to 1.5. A stand-ard -based on a 1.5 GSD would be farmore stringent than using 1.3. EPAtook the 1.3,' however, because of itsconcern that the total geometricstandard deviation -contains variationattributable to monitoring and analyt-ical methodology. In estimating the re-lationship between air lead and blood


lead to be 1:2, the Agency used an epi-demiological study of children near asmelter, Yankel et al, where responseof blood lead to air lead averaged overthe exposure. range was 1 to 1.9. Inadopting- 12 pg Pb/dl as the part ofblood lead attributable to nonairsources, EPA Is concerned that typicallevels for this component may bemuch greater, and that regulatory ac-tions by other public health piogramsmay be necessary to achieve a 12 pglevel.

Because of the variability betweenindividuals in a population experlenc-ing-a given level of lead exposure, EPAfinds it is impossible to provide thesame amount of margin of safety forall members in the sensitive popula-tion, or to define the margin of safetyin the standard as a simple percent-age. EPA does believe that the factorsIt has used-in designing the standardprovide an adequate margin of safetyfor a large proportion of the sensitivepopulation. The Agency does not be-lieve. that this margin Is excessivelylarge or on the other hand that the airstandard can protect everyone fromelevated blood lead levels.

THE IMPORTANCE OF THE RESPIRABLE

FRACTION OF TOTAL AM LEAD LEVEL

The Agency received a number ofcomments expressing concern that, be-cause only a fraction of airborne par-ticulate matter is respirabl% an airstandard based on total air lead is un-necessarily stringent.

AGENCY RESPONSE

EPA agrees that some lead particlesare too small or too large to be depos-ited in the respiratory system. EPAcannot conclude, however, that parti-cles outside of the respirable range donot represent an exposure hazard. Asignificant component of exposure canbe ingestion of materials contaminatedby deposition of lead from the air. Inaddition to the indirect route of inges-tion and absorption from the gastroin-testinal tract, nonrespirable lead inthe environment may, at some point,become respirable through weatheringor mechanical action. EPA concludes,therefore, that total airborne lead,both respirable and nonrespirablefractions, should be addressed by theair standard.

ECONOMIC IMPACE OF THE PROPOSED

STANDARD

A number of commenters were crti-cal of the Agency's economic impactassessment, and argued that the fore-cast underestimated the severity ofthe economic impact to certain lead In-dustries.

46251

AGENCY RESPONSE

The comments critical of the draftimpact statement did not include datawhich would allow EPA to confirm thepossibility of more severe economicImpacts on certain source categoriesincluding primary and secondary leadsmelters which could have difficulty inlimiting emissions sufficiently toassure attaining the standard in theirimmediate vicinity. Under the CleanAir Act, the primary responsibility forimplementing the standard is assignedto the States and each State is re-quired to submit a plan to EPA dem-onstrating how attainment is to beachieved. The actual economfimpactsof Implementation are difficult to esti-mate at this time since, following pro-mulgation, States wil have 9 monthsto develop and submit these plans toEPA. The plans must demonstrate at-tainment as soon as practicable, but nolater than 3 years following the dateof plan approval. However, under cer-tain circumstances, States may request;up to a 2-year extension of this dead-line. Other sections of the Clean AirAct may be used with the Administra-tor's discretion to grant further exten-sions of compliance deadlines for im-pacted industrial facilities.

EPA cannot. at this time accuratelypredict the impact of this standard,but with the timetable in the Act, seesno reason to expect imminent closureof any facility. The Agency is commit-ted to developing accurate data forspecific plants in cooperation with theIndustry and State agencies in order toavoid the imposition, of mmecessaiycontrols. EPA's principal concern,however, must be to follow the man-date of the Clean Air Act relating tothe protection of the public health.

EPA believes that the economicImpact asessment is a reasonable fore-cast of the economic consequences ofimplementation of the standard.

T= PROPOSED STATE nbOLEXATIOnPLAN (SIP) REGULATIONs

A summary of comments and theAgency response is included n thepreamble to the final regulations pub-lished elsewhere in this MlmErgA EG-.ISTER.

THE FEDERAL REFERENCE METZOD FOR.MONITORING LEAD AIR QUALITY

A summary of conments and theAgency's disposition is included in thepreamble to the final method pub-lished elsewhere In this FEDERAL.EG-

THE ADMINISTRATIVE PROCEDURES EM-PLOYED BY EPA IN THE DEVELOPM[ET OPTH PROPOSED STANDARD AD THE PRO-VIS16N FOR PUBLIC PARTICIPATION

Two conmenters requested thatcross examination of witnesses be al-

FEDERAL REGISTER, VOL 43, NO. 194-THURSDAY, OCTOBER. 5, 1978


lowed in the post-proposal public hear-ing on the proposed standard and im-plementation regulations. EPA also re-ceived a request to postpone the publichearing and to extend the commentperiod, citing the need to complete on-going studies.

AGENCY RESPONSE

Both the request for cross-examina-tion and the extension of the com-ment period were denied by theAgency. With regard to the request forcross-examination, the Agency deter-mined that, in light of the extensivereview already conducted, cross-exami-nation was not likely to produce newinformation or results that would jus-tify such a-significant departure fromthe normal rulemaking process. Alsothe existence of the normal commentperiod was sufficient to allow interest-ed members of the public to raisequestions concerning the Agency's de-terminations. Further, due to the ex-tensive review opportunities availableat all stages of the regulatory develop-ment, an extension of the commentperlbd was not believed to be suffi-ciently necessary to further delay theschedule f6r preparation of the final.rule.

°CLARIFICATION OF ELEMENTS OF TnESTANDARD

From reviewing the comments re-ceived, EPA wishes to clarify the fol-lowing points in the presentation ofthe rationale for the final standard:

(1) EPA is making a distinction be-tween the blood Jead level that, is thethreshold for detection of the biologi-cal effect, impaired heme synthesis,and the blood lead level at which thiseffect has progressed to an extent thatit is regarded as adverse to health.

(2) EPA is making a distinction be-tween estimating a maximum safeblood lead level for an individual child,and establishing a population targetgeometric mean blood lead level forthe sensitive population.

(3) EPA is making a distinction be-tween what the contribution to bloodlead levels from nonair sources actual-ly may be, and attributing a contribu-tion from nonair sources for the pur-pose of standard setting.

DERIVATION OF THE NUMERICAL LEVEL OFTHE FINAL STANDARD

,EPA's objective in setting the levelof the standard is to estimate the con-centration of lead in the air to whichall groups within the general popula-tion can be exposed for protracted pe-riods without an' unacceptable risk to'health.

This' estimate is based on EPA'sjudgment in four key areas:

(1) Determining the "sensitive popu-lation" as that group vithin the gener-al population which has the lowest

threshold for adverse effects or great-est potential for exposure. EPA_ con-cludes that young children, aged 1 to5, are the sensitive population.

(2) Determining the safe level oftotal lead exposure for the sensitivepopulation, indicated by the concen-tration of lead in the blood. EPA con-cludes that the maximum safe level ofblood lead for an individual child is 30jig Pb/dl and that population bloodlead, measured as the geometric mean,rhust be 15 jig Pb/dl in order to place99.5 percent of children in the UnitedStates below 30 jg Pb/dl .

(3) Attributing the contribution toblood lead from nonair pollutionsources. EPA concludes thaf 12 jIg Pb/dl of population blood lead for chil-dren should be atttributed to nonairexposure.

(4) Determining the air lead levelwhich is consistent with maintainingthe mean population blood lead levelat 15 jig Pb/dl. Taking into'accountexposure from other sources (12 jigPb/di) EPA has designed the standardto limit air contribution after achiev-ing the standard to 3 jug Pb/dl. On thebasis of an estimated 'relationship ofair lead to blood lead of 1 to 2, EPAconcludes that the ambient air stand-ard should be 1.5 1zgFPb/m3.

Each of these four areas is discussed- further in the following sections.

SENsITIVE POPULATION

EPA believes that the health ofyoung -children is at particular riskfrom lead exposure.- This is becausechildren have a greater physiologicalsensitivity to the effects of lead thando adults and may have greater expo-sure to environmental lead from play-ing in contaminated areas. Other sen-sitive populations identified by EPAinclude those occupationally exposed,and pregnant women and their fe-tuses. Comments received on the pro-posed standard did not challengeEPA's position that young childrenare the most sensitive populition fordetermining the standard. A numberof comments did point out that withinthe general population of childrenthere' were subgroups with enhancedrisk due to genetic factors, dietary de-ficiencies, or residence in urban areas.EPA acknowledges the higher - riskstatus of such groups but does nothave information either in the airquality criteria or in the comments re-ceived for estimating a threshold foradverse effects separate from that ofall young children. Concern aboutthese high risk subgroups has, howev-er, influenced EPA's determination ofthe percentage of the population ofchildren (99.5 percent) to be main-tained below 30 jig Pb/dl.

EPA continues to' be. concernedabout the possible health risk of leadexposure for pregnant women and

their fetuses. The stress of pregnancymay place pregnant women In a statemore susceptible to the effects of lead,and,transplacental transfer of leadmay affect the prenatal developmentof the child. There is, however, Insuffi-cient scientific Information for EPA toeither confirm or dismiss this sugges-tion, or to establish that pregnantwomen and fetuses are more at riskthan young children.

THE MAXIMuM SAFE EXPOSURE FORCHILDREN

In determining the maximum safeexposure to lead for children, EPA hastaken the measurement of blood leadas the indicator of total lead dose.There are other possible indicators ofexposure, for example the level of zincprotoporphyrin (ZPP), but mosthealth studies reported in the criteriadocument utilize blood lead levels asindications of the mobile body burdenof lead. The criteria document reportsthe following table of effect thresh-olds ,for children with increasing-bloodlead levels.

SUMMARY OF LOWEST OBSERV, MEf ECT LEVELSIN YOUNG CHILIREN

pv Pb/dl8-ALAD inhibition ..................... ............. 10Erythrocyte protoporphyrin elevation 15-20Increased urinary 8-ALA excretion .......... 40Anemia ......................................................... 40Coproporphyrin elevation ................... ... 40Cognitive (CNS) deficits .................... 50-00Peripheral neuropathics ......................... 50-00Encephalopathic symptoms .................... 80-100

(P. 13-8)

The first physiological effect associ.ated with increasing blood lead levelsis the Inhibition of the enzyme 8-amin-olevulinic acid dehydratase (8-ALAD),both in red blood cells (erythrocytes),and In cells In other tissues. Thisenzyme catalyzes the condensation oftwo molecules of 8-aminolevulinle acid(8-ALA) to form porphobilinogen, oneof the components involved in the cel-lular synthesis of heme. The criteriadocument reports that the thresholdfor 8-ALAD inhibition in children is 10jig Pb/di.

At blood lead levels above 10 Ag Pb/di, the function of 8-ALAD Is Increas-ingly inhibited by lead. The criteriadocument states that 40 pg Pb/dl Isthe threshold for elevation of 8-ALArecognized as 8-ALA in the urine or 8-ALA-U, an indication that 8-ALA hasbegun to accumulate In cells.

EPA does not regard the inhibitionof 8-ALAD above 10 jg Pb/dl as ad-verse to health because of the absenceof evidence that there Is an impair-ment of heme synthesis until a thresh-old of 40 jig Pb/dl Is reached. The ac-cumulation of 8-ALA above normallevels, indicated by 8-ALA-U, Is re-garded as adverse to health, both be-cause .of impaired heme synthesis, and


46252

the possibility that 8-ALA accumula-tion is itself toxic to cells.

The criteria document reports thatabove a threshold of 15-20 pg Pb/dUthere is an elevation of protopor-phyrin in erythrocytes. Protopor-phyrin is an organic chemical com-pound used by all cells in the produc-tion of heme. In the final stage ofheme synthesis, erythorocyte proto-porphyrin (EP) and iron are broughttogether in the cell mitochondria. Inthe presence of lead, this step isblocked, possibly by inhibition of theenzyme ferrochelatase or by interfer-ence-in the transport of iron acrossthe mitochondrial membrane. Withoutincorporation into heme, the levels ofprotoporphyrin in the cell become ele-vated.

From review of the information pro-vided by the air quality criteria docu-ment as wellas the evidence and argu-ments offered by medical professionalscommenting on the proposed stand-ard, EPA has concluded that the ef-fects of lead on the cellular syntheisof heme, as indicated by elevatederythrocyte protoporphyrin, are po-tentially adverse to the health ofyoung children. This appears, howev-er, to be a question of the degree towhich the effect has progressed. EPAdoes not believe that there is signifi-cant risk to health at the point wherethe elevation of EP can first be corre-lated with an increase in blood lead(15 to 20 jig Pb/dl). On the otherhand, EPA regards as clearly adverseto health the impairment of hemesynthesis, and other effects of leadwhich result in clinical symptoms ofanemia above 40 pLg Pb/dl. These ef-fects are followed quickly by the riskof nervous system deficits for somechildren with blood lead levels of 50 pgPb/dl.

EPA has concluded that the maxi-mum safe blood lead level for an indi-vidual child is 30 pg Pb/dl. This isbased on the following factors:

(1) The maximum safe blood leadlevel should be somewhat lower thanthe threshold for a decline in hemo-globin levels (40 pg Pb/dl).

(2) The maximum safe blood leadlevel should be at an even greater dis-tance below the threshold for risks ofnervous system deficits (50 pg Pb/dl).

(3) The maximum safe blood leadlevel should be -no higher than theblood lead range characterized asundue exposure by the Center for Dis-ease Control of the Public HealthService, as endorsed by the American-Academy of Pediatrics, because of ele-vation of erythrocyte protoporphyrin(above 30 pg Pb/dl).

(4) The maximum safe blood leadlevel for an individual need not be as


low as the detection point for the ini-tial elevation of EP (15-20 pg Pb/dl).

The criteria document points outthat data from epidemiological studiesshow that the log values of measuredindividual blood lead values In a uni-formly exposed population are nor-mally distributed with a geometricstandard deviation (GSD) of 1.3 to 1:5.Using standard statistical techniques,it Is possible to use the geometricstandard deviation to calculate themean population blood lead levelwhich would place a given percentageof the population below the level of aneffects threshold. A GSD of 1.5 wouldresult in a lo*er geometric mean, anda more stringent standard. However,because some of the variability in theGSD is from measurement systems,EPA has used a GSD of 1.3.

Recently, analysis of the data col-lected by New York City's Bureau ofLead Poisoning has shown that popu-lations of children In the New Yorkarea consistently have distributions ofblood lead values with a GSD of 1.4 to1.5. With a geometric mean of 15.0 pgPb/di, a GSD of 1.4 results in abouttwo percent of the population overlevels of 30 pg Pb/d. A GSD of 1.5would place more than four percentover 30 pg Pb/dl. EPA is concernedthat such results may Imply that thestandard Is not as precautionary as Itwould be if the actual GSD was 1.3.However, the Agency's best estimate isthat some of the GSD is from analyt-ical and monitoring variance, and forthis reason, EPA Is using the 1.3 valuein calculating the final standard.

In EPA's view, use of the 99.5 per-cent range Is not excessive. From 1970statistics, there are approximately 20million children In the United Statesbelow the age of 5 years, 12 million inurban areas, and 5 million In centercities where lead exposure may behigh. Again, khowledge that there arespecial high risk groups of childrenwithin the general population detersEPA from considering lower percent-ages.

CoNTaIuTION To TOTAL LnwExPosuRE FROM NONAM SouRcEs

In the proposed standard, EPA.argued that the air standard shouldtake into account the contribution toblood lead levels from lead sources un-related to air pollution. No, commentswere received challenging this argu-ment. EPA continues to base Its calcu-lation of the.amblent air standard onthe assumptions that, to an extent,the lead contribution to blood leadfrom. nonair sources should be sub-tracted from the estimate of safemean population blood lead. Withoutthis subtraction, the combined expo-sure to lead from air. and nonair

46253

sources would result in a blood leadconcentration exceeding the safe level-

EPA notes that the level of thestandard Is strongly influenced byJudgments about nonair contributionto total exposure, and that there aredifficulties in attempting to estimateexposure from various lead sources.Studies reviewed in the criteria docu-ment do not provide detailed or wide-spread information about the relativecontribution of various sources to chil-dren's blood lead levels. Estimates canonly be made by Inference from otherempirical or theoretical studies, usual-ly involving adults. Also, It can be ex-pected-that the contribution to bloodlead levels from nonair sources canvery widely, is probably not in con-stant proportion to air lead contribu-tion, and in some cases may aloneexceed the target mean populationblood lead leveL

In spite of these difficulties, EPAhas attempted to assess available in-formation in order to estimate thegeneral contribution to populationblood lead levels from air and nonairsources. This has been done with eval-uation of evidence from general epide-miological studies, studies showing de-Cline of blood lead levels with decreasein air lead, studies of blood lead levelsin areas with low air lead levels, andisotopic tracing studies.

Studies reviewed by the criteria doc-ument show that the geometric meanblood lead levels for populations ofchildren are frequently above 15 pgPb/dl. In studies reported, the rangeof mean population blood lead levelsfor children was from 16.5 pg Pbldl to46.4 pg Pb/dl with most studies show-ing mean levels greater than 25 pg Pb/dl (Fine, 1972; Landrgan, 1975; vonLindern. 1975). EPA believes thaf, formany of these populations, the contri-bution to blood lead levels from nonairsources may exceed the desired targetmean blood lead level.

In a number of studies, reduction inair lead levels resulted in a decline inchildren's blood lead levels. A study ofblood lead levels in children in NewYork City showed, that children'smean blood lead levels declined from30.5 pg Pb/dl from 1970 to 1976, whileduring the same period air lead levelsat a single monitoring site fell from 2.0pg Pb/dl to 0.9 pg/Pb (Billick, 1977).Studies at Omaha, Nebr. (Angle, 1977)and Kellogg, Idaho (Yankel, von Lin-dern. 1977) also show a drop in meanblood lead levels with declines in airlead levels. As air lead levels declinethere appears to be a rough limit tothe drop in blood lead levels. ,

EPA has also examined epidemiolog-Ical studies in the criteria documentwhere air lead exposure is low, andcan be assumed to be a minor contrib-utor to blood lead. These studies pro-vide an indication of blood lead levelsresulting from a situation wherenonair sources of lead'are predomi-nant.

FEDERAL REGISTER, VOL 43, NO. 194-TURSDAY, OCTOBER 5, 1978

46254 RULES AND REGULATIONS

STUDIES REPORTING BLOOD LEAD LEVELS IN CHILDREN EXPOSEDTO M ODERATE TO LOW Am LEADLEVELS

Investigator Blood Air lead2 Comment

lead'

Hammer. 1972 ... . ......... ...... .............. 11.6 0.1 ............ Children in Helena, Mont.Angle,1974 .................. ; .......... . . . 14.4 0.14 .................... Suburban Children ages 1 to -4 In

Omaha, Nebr.Goldsmith, 1974 ...................... 13.7 0.2 to 0.7 .......... Children in Benecla Calif.

0.3 to'0.6Children in.

JCrocket, Calif..Johnson, TiIery, 1975............10. .... Female children-mean age 9 in

Lancaster Calif.

'In micrograms of lead per deciliter.2 In micrograms of lead per ctbic meter.

The range of mean blood lead levelsJinthose studies is from 10.2 jig Pb/dI to14.4'lpg Pb/,dl, with an average at12.7pg Pb/dl.

In addition to epidemiological inves-tigations, EPA -has reviewed studiesthat examine the -source of blood leadby detecting characteristic lead iso-topes. A study using isotopic tracing(Manton, 19.77) suggests that for sever-al adults in Houston, Tex., 7 to 41 per-.cent of blood lead could be attributedto air lead sources. An earlier isotopic-study .(Rabinowitz, 1974) concludedthat for two -aduflt'male subjects stud-ied, approximately one-third of totaldaily intake of lead could be attribut-ed to exposure to air lead levels of 1-2pg Pb/m. While these results -cahnotbe directly related to children,- it 'isreasonable to assume that children-may exhibit the san3ie or higher per-centages of air lead contribution toblood lead level because of a greaterpotential for exposure to indirect airsources, soil and dust.

From reviewing these areas of :evi-dence, EPA concludes that:

1. In studies showing -nean bloodlead levels above 15 pg Pb/d, it isprobable that both air and nonairsources of lead contribute significantlyto blood lead with the possibility thatcontributions from ,nonair sourcesexceed 15 pg Pb/dl.

2. Studies showing -a sustained dropin air lead levels show a correspondingdrop in blood lead levels, down to 'an,apparent limit in the range -of 10.2 -to14.4 pg Pb/di.'

3. Isotopic tracing studies showt aircontribution to blood lead to -be 7-41.percent in one study and about 33 per-cent In another study.

In considering -this evidence, EPAnotes that if, from the isotopic Studies,.aproxmatlytwo~thirds ,of blood

iead is typically derived from honairsources, a-meanblood lead'target of 15pg -Pb/di would attribute 10 lg Pb/dIto non-air sources. On the other hand,the average blood lead level from -thelimited studies available where air ex-posure was low is 12.7 )ig Pb/di. In theabsence of' more precise information,

EPA is calculating th6 lead standardbased on the attribution of 12 pg Pb/dl of the-blood lead level in children tolead sources unaffected by the lead airquality standard. EPA is aware that.actual population blood lead levels,either individually or as a populationmean, may exceed this benchmark.'However,- if EPA were to use a largerestimate of non-air contribution toblood lead, the -result would be an ex-ceptionally- stringent standard, whichwould-not address the principal sourceof lead exposure.

THE' RELATIONSHIP BE wN AIR m-ADExPosURE AND RESULTING - BLOODIXAD IZVL

E:A hai reviewed the studies dis-cussed in the criteria -document whichreport changes in blood lead levelswith different air Jead"levels. TheAgency , believes -that, one of thestrongest epidemiological studies isthat by Azar et al., which used person--aLdosimeters to measure lead intake.This eliminated some of the ulicertain-ty ,about the extent to which air -qual-ity observations accurately reflect-actual exposure. From the Azar data,the relationship of lead in the air tolead in the blood, evaluated at 1.5 pg-Pb/m,. was 1:1.8. The Azar study was,however, limited to an adult popula--tion.

A clinical study of adults, *Griffin etal., gives roughly the same conclusionfor a group of adults confined to achamber with ontrolled exposure tolead aerosol. This study was conductedover a'three month period with .con-trol over lead ingestion. As air lead.levels in the chamber were increasedfrom 0.15 -pg Pb/m3 .to 3.2 pg Pb/m 3,the air lead-to blood lead relationshipwas -1:1.7.

Because children are known to havegreater net absorption and retentionof lead than adults, it is reasonable toassume that the -air lead to -blood leadrelationship for this sensitive popula-tion, exposed to air lead levels in therange of the _proposed standard, isequal to if not greater than for adults.EPA also notes that -the air lead toblood lead relationship is nonlinear

which will result in a higher ratio atlower air levels.

In an epidemiological study of chil-dren near a smelter, Yankel et al., theresponse of, blood lead to air lead, av-eraged over the exposure range, was1.95. This study provided informationon the relationship of blood lead to airlead over a very large range of air leadvalues. The air lead values in thestudy are the result of a model cali-brated by monitoring data. The rela-tive error, of the individual values, es.pecially in the low range is larger thinin the Azar study.

The authors of the study, Yankeland von Lindem, chose a log-linearmodel which provided a good fit to thedata and gave an estinated slope ofabout 1.2 at an air lead of 1.5. Howev-er, EPA sees a problem with a log-linear model in that It forces a lowerslope at low air lead values and ahigher slope at higher lead values,This is i-i direct 'contradiction to the

,Azar and the Griffin studies, both ofwhich indicate higher slopes at lowerair lead values.

Because of the uncertainties in thelow air lead values in the Idaho study,,EPA -felt that the calculation of anaverage slope or ratio over the entirexange of data would be a moderatecompromise. The calculation of anaverage slope gives a value of 1.95.EPA believes that these studies as wellas others reported in the criteria docu-ment support the document's conolu-sion that:ratios between blood lead levels and air leadexposures were shown to range generallyfrom 1:1 to 2:1. These were not, however,constant over the range of air lead concen-trations encountered. There ar6 suggestivedata Indicating that the ratios for children.are In the upper end of the range and mayeven be slightly above it. There is also some'slight suggestion that the ratios for malesare higher than those for females. (pp. 12-38.)

CALCULATIoN oF TuE AIR STANDARD

EPA has calculated the standardbased on the conclusions reached Inthe previous sections;

1. Sensitive population: Children. ages 1-5.2. Health basis: Maximum safe blood lead

level for individual children Is 30 pg Pb/di-based on concern for impaired heme synthe-sis above .30 pg Pb/dl and margin o1 safetyfor anemia above 40 jg Pb/d and ngrvoussystem deficits above 50 pg Pb/dI.

3. Maximum safe geometric mean bloodlead for children based on placing 99,5 per-cent of the sensitive population below the30 pg Pb/al level of concern: 15 pg Pb/d.

4. Estimate of blood lead level attributedto non-air sources: 12 pg Pb/dl.

5. Allowable contribution to blood leadfrotm air sources after achieving the stand.ard: 15 pg Pb/dl-12 pg Pb/dl=3 pg Pb/d.

6. Air lead concentration consistent withblood lead contribution from air sources: 3pg Pb/dlxl pg Pb/m3 air/2 pg Pb/dlblood= 1.5 pg Pb/m.

FEDERAL-REGISTER, VOL 43, NO. 194-THURSDAY, -OCTOBER 5, 3978

SELECTION OF THE AVERAGING PERIODFOR THE STANDARD

Based on. comments received andconsideration by the Agency, the pro-posed- averaging period of a calendarmonth is extended to a calendar quar-ter. EPA believes that this change willsignificantly improve the validity oflead air quality data which will begathered to monitor progress towardattainment without placing an undueburden of State and local environmen-tal agencies, or significantly reducingthe protectiveness of the standard.

The Agency believes that the keycriteria for the averaging period is theprotection of the health of the sensi-tive population. In proposing the 1.5jg Pb/m3 standard, EPA concludedthat -this air level was safe for youngchildren with an indefinie exposureperiod. The critical factor in the deter-mination of the averaging period isthe health significance of possible ele-vations of air lead above 1.5 gg Pb/m3

which could be encountered for shortperiods without causing average levelsto exceed the standard. In the pro-posed standard, EPA chose a calendar"month averaging period on the basisof a study (Griffin et al.) showing anadjustment period of blood lead levelwith a change in exposure. Because ofthe scientific and technical difficultiesof the monthly stan~lard, EPA hasreexamined this question and conclud-ed that there is little reason to expectthat the slightly greater possibility ofelevated air lead levels sustainable bythe calendar quarter standard is sig-nificant-for health. This conclusion isbased on the following factors:

(1) From actual ambient measure-ments, there is evidence that the dis-tribution of air lead levels is such thatif the quarterly average was achieved-there is little possibility that therecould be sustained periods greatlyabove the averageyvalue.

(2) While it is difficult to relate theextent to which a monitoring networkactually represents the exposure situa-tion for young children, it seems likelythat where elevated air lead levels dooccur, they will be close to point ormobile sources. Typically, young chil-dren will not encounter such levels forthe full 24-hour period reported bythe monitor.

(3) There is medical evidence indi-cating that blood lead levels reequili-brate slowly to changes in air expo-sure. This serves to dampen theimpact of a short-term period of expo-sure to elevated air lead.

(4) Direct exposure to air is only oneof several rputes of total exposure.This lessens the impact of a change inair lead on blood lead levels.

On balance, the Agency concludesthat a requirement for the averaging-of air quality data over a calendarquarter will improve the validity of air


quality data gathered without a sig-nificant reduction in the protective-ness of the standard.

MARGIn OF SAFE

The Clean Air Act instructs EPA toset the level of an ambient air qualitystandard at a level which protects thepublic health with a margin of safety.One approach to using margin ofsafety is to estimate the air concentra-tion of a pollutant that Is the thresh-old for the first adverse effect detect-ed with increasing air levels, and thenset the air standard at a somewhatlower level. The extent of the safetymargin between the standard and theestimated threshold for adverse ef-fects is influenced by such factors asthe severity or irreversibility of ef-fects, the degree of uncertainty aboutknown or suspected health effects, thesize of the population at risk, and pos-sible interactions of several pollutantsin potentiating health effects. Whilethe margin of safety is basek on avail-able scientific information, this factoris judgmental in that the AdminI tra-tor must weigh the acceptability of es-timated risk.

Estimating an appropriate margin ofsafety for the air lead standard incomplicated by the multiple sourcesand media for lead exposure. Becauseof this, EPA has elected to use marginof safety considerations in estimatingthe maximum safe level for blood lead,and the percentage of the sensitivepopulation to be placed below thislevel, rather than making a final ad-justment to concentration of lead inthe air. EPA has adopted 30 pg Pb/dlas the maximum safe blood lead levelfor individual children, and the airstandard is calculated to maintainmost children below this target. Onthe basis of Information developed inthe criteria document and from publiccomment, blood lead levels between 30and 40 pg Pb/dl are associated withimpairments of the heine syntheticpathway which EPA regards as ad-verse to health. Blood lead levelsabove 40 pg Pb/dl are associated witha decline in hemoglobin levels, andlevels above 50 jig Pb/dl are associatedwith the risk of nervous system defi-cits for some children. With a geomet-ric mean population blood of 15 pigPb/dl lead, most children will be wellbelow these'thresholds, but a smallpercentage can be expected to haveblood lead levels of concern.

Because of the variability betweenindividuals in a population experienc-ing a given level of lead exposure, EPAfinds that it is not possible to providethe same amount of margin of safetyfor all members in the sensitive popu-lation, or to define a margin of safetyin this standard as a simple percent-age. In developing the numerical levelof the standard, EPA used evidence in

46255

the criteria document that the bloodlead levels for individuals in a givenpopulation of children are log-normal-ly distributed. The statistical proper-ties of this distribution make it possi-ble to calculate the percentage of thepopulation which will fall below anygiven blood lead level. Individuals ateach of these levels would have a" dif-ferent margin of safety below themaximum safe blood lead level. As'arough example, with a population ofchildren with a geometric mean bloodlead of 15 pig Pb/di, 86 percent of thechildren would be below 20 pug Pb/dl,97.5 percent would be below 25 pig Pb/dl and 99.5 percent would be below 30pg Pb/di. Assuming a population ofchildren In central urban areas whereair lead was at the standard level,693,000 children would be over 20 lgPb/d, 126,500 oier 25 pug.Pb/d, and20,605 above 30 pg Pb/di.

In determining the appropriatemargin of safety, the Agency has alsoincluded consideration of the &follow-ing factors:

(1) In addition to the health effectsdiscussed, the "Air Quality Criteria.forLead" report multiple biological in-volvements of lead in practically allcell types, tissues, and organ systems.The significance for health of thesehas not been fully studied.

(2) There are no beneficial effects oflead at current environmental levels.

(3) EPA has incomplete data aboutthe extent to which children are indi-rectly exposed to lead from air leadwhich moves to other environmentalmedia, such as water, soil and dirt, andfood.

(4) Lead is chemically persistent andwith continued uncontrolled emissionswill continue to accumulate both inhuman tissue and in the environment:

(5) There is a possibility that leadexpospre resulting in blood lead levelspreviously considered safe may in factinfluence the neurological develop-ment and learning abilities of theyoung child. EPA does not have evi-dence, however, that provides morethan a suggestion that this couldoccur at blood lead levels below 30 Pb/dl for individual children.

TMPACT OF LEAD DUSTrALL ON BLOOD LEAD

In the preamble for the proposed airstandard for lead, EPA pointed outthat the significance of dust and soillead as indirect routes of exposure hasbeen of particular concern in the caseof young children. Play habits andmouthing behavior between the agqsof 1 and 5 have led to the conclusion

*that greater potential may exist inthese children for ingestion and inha-lation of the lead available in contami-nated dust and soil. EPA is also con-cerned that the deposition of lead par-ticles can lead to general contamina-tion of the environment and increased


46256

lead exposure from surface waters andfoodstuffs.

Studies -reviewed in the criteria doc-ument indicate a correlation betweensoil and dust levels and childrens'blood lead levels in highly contdiminat-ed environments (Yankel and Von Lin-dern, 1977; Barltrop, 1974; Galke, inpress). The lead threshold for concernhas been reported as'1,000 parts permillion (ppm) in soil (Yankel and vonLindern, 1977). At levels of between500 and 1;000 ppm in soil; the criteriadocument concludes that 'blood leadlevels begin to increase. A twofold -in-crease in soil concentration in thisrange is predicted to result in a 3-6percent rise in blood lead levels. Below500 ppm lead -in soil, no correlationhas been observed with blood leadlevels. *-

The normal background for lead insoil is cited in the criteria document as15 ppm. Due to human activities, theaverage levels in most -areas of theUnited States are considerably-higher.Soil studies conducted by EPA's Offiseof Pesticides Programs from 1974 to1976 in 17 urban areas reported onlyk3,cities with arithmetic mean concentra-tions in excess of 200 ppm, with thehighest valud 537 ppm. Concentrationsin the soils surrounding large pointsources of lead emissions, or heavilytravelled roads may reach many thou-sand ppm.

Because of 'the many factors in-volved, EPA is unable to predict therelationship between air lead levels,dustfail rates, and resulting soil accu-mulation.. Complicating factors in-clude: Particle size distribution, rain-out, other meteorological iactors, to-";pographical features affecting deposi-tion, and removal Iechanisms.

EPA believes, however, that -signifi-cant impacts on blood lead- of -soil nddust lead are mainly limited to areasof high soil concentration (in excess of1,000 ppm) around large point sourcesand heavilytravelled roads. Evidencesuggests that soil lead-levels in, areaswith air lead levels in the range of thestandard are below the" threshold for,lead health impact (Johnson, Tillery,1975; Johanson, 1972; EPA, 1975 AirQuality Data and Soil Levels).

Comments ,received on the proposedstandard argued that the lead -airstandard should be limited -to respira-ble size lead particulate matter, aslarger' particles would fall to theground without being deposited or ab-sorbed in the lung. "EPA has decidednot to accept this recommendation be-cause, as discussed above, larger parti:cles can contribute to lead dose byhuman ingestion of airborne particles,by contamination of other environ-mental media, or by eventual reduc-tion to respirable size by mechanicalaction or weathering.

RULES AND REGULATIONS-

WELFARE EFEcTs

Comments received on the proposedlead air quality standard did not ad-dress the issue of welfare effects orthe need-for a secondary air qualitystandard more restrictive than the pri-mary standard. EPA maintains its po-sition that the primary air qualitystandard 'will adequately protectagainst known and anticipated adverseeffects on public welfare. EPA 'doesnot have evidence that a more restric-tive secondary standard would be jus-tified.

Available evidence cited in the crite-'ria document indicates that animals-do not appear to be more susceptible'to adverse effects from lead than man,,nor do adverse effects in animals occurat lower levels of exposure than. com-parable effects in humans.

Lead is absorbed but not accumulat-- ed to any great extent by plants from

soil. Lead is, either unavailable toplants or is fixed in the roots and only.small amounts are transported to theabove ground iportions. Lead may be

'-deposited on the leaves- of-plants and,present a hazard to grazing animals.Although some plants may be suscep-tible to lead in the natural environ-ment, it-is generally in a form that islargely nonavailable to them. '

There is no evidence to indicate thatambient levels of lead result in signifi-cant damage to manmade materials.Effects of -lead on visibility and cli-mate are minimal.

Based on such data, EPA promul-gates the secondary air quality stand-ard for lead at 1.5 pg Pb/m 3, calendar-quarteraverage.

EcoNomicIMPaAcT ASSESSMENT

-As, required by Executive Orders11821 and 12044, EPA has conducted ageneral analysis - of the economic-impact which might xesult from theimpleme;ntation of 'the lead xegula-tions. This arialysis was not intendedfor nor was it used in the developmentor promulgation of the standard, andwas issued for informational purposesonly. I I

The economic impact assessmentpoints out that the categories ofsources likely to be affected by controlof lead emissions are primary lead andcopper smelters, secondary lead smelt-ers, gray iron foundries, gasoline lead

'additive manufacturers, and lead stor-age battery manufacturers. This anal-ysis further indicates that some prima-ry and secondary lead smelters andcopper smelters may be severlystrained economically in achievingemission reductions that may be re-quired in implementing the proposedair quality standard. -

There are, however, uncertainties as-sociated with evaluating the impact-ofattaining the standard. For smeltersand foundries, -attaining the standard

may require control of fugitive leademissions, i.e., those emissions escap.ing from individual process operations,other than emissions from smokestacks. Fugitive emissions are difficultto estimate, measure, and control; andit is also difficult to predict theirimpact on air quality near the facility.From the information available toEPA, nonferrous smelters may havegreat difficulty in achieving lead airquality levels consistent with the pro-posed standard in areas immediatelyadjacent to the smelter complex.

The change in averaging time from amonthly average to a calendar quarteraverage will affect the economic Im-pacts associated with the lead stand.ard because for a given level of thestandard, a longer averaging period istheoretically less stringent than" ashorter averaging period.

OTHR LEAD REGULATORY AND CONTROLPROGRAMS

EPA's ambient air quality standardis only one of a nuber of Federal,State, and local programs designed tolimit exposure to lead.

In 1975, EPA promulgated the na-tional interm primary drinking waterregulation setting a maximum con.taminant level for lead. The standard,aimed at protecting children fromundue lead exposure, was'set at 50 pgPb/liter. In 1977, the National Acade-my of Sciences concluded that a leadlevel at which adverse health effectsare observed cannot be set with assur-ance at any value greater than 25 ygPb/liter. The Office of -DrinkingWater is currently considering theneed to revise the interim drinkingwater standard for lead,

Based on Its toxicity, EPA has n.cluded lead on Its list of priority waterpollutants for which effluent guide.lines are being developed under theClean Water Act. Effluent guidelinesare being developed for lead for non-ferrous smelters, based on achieve-ment of best available technology.

EPA's Office of Pesticide Programs,has promulgated regulations based onthe toxicity of lead which require theaddition of coloring agents to the, pes-ticide lead arsenate and specify dispos-al procedures for lead pesticides. Useof lead in pesticides is a small and de-creasing proportion of total lead con-sumption in the United States.

The Resource Conservation and Re-covery Act (RCRA) of 1976, throughwhich EPA Is to establish standardson how to treat, dispose, or store haz-ardous wastes, provides a means forspecifying how used crankcase oil andother. waste streams containing leadshould be recycled or safely disposedof. Regulatory actions related towastes containing lead are currentlybeing developed under subtitle C ofRCRA.


EPA has regulations for reducingthe average lead content in the totalgasoline pool to 0.5, grams/gallon byOctober 1, 1979, and Tegulations pro-viding for lead-free gasoline requiredfor cars equipbed 'with catalytic con-verters and other vehicles certified foruse of unleaded fuel. The former regu-lations are based on reducing exposureto airborne lead to protect publichealth. Other EPA actions whichresult in the reduction of airbornelead levels include ambient standardsand State implementation plans forother pollutants such as particulatematter and sulfur dioxide and newsource performance standards limitingemissions of such pollutants. Existingand new sources of particulate matteremissions generally use control tech-niques which reduce lead emissions asone component of particulate matter.

The Occupational Safety and HealthAdministration 'proposed regulationsin 1975 to limit occupational exposureto lead to 100 pg Pb/ni3, 8-hour time-weighted average. The exposure limitwas based on protecting against ef-fects, clinical or subclinical, and themild symptoms which may occurbelow 80 pg Pb/dL providing an ade-quate margin of safety. The level of100 gg Pb/m 3 is anticipated to limit

zblood lead levels in workers to a mean40 pg Pb/dl and a maximum of 60 pgPbjdL OSHA is presently reviewingthe latest information on lead expo-sure and health effects in preparationfor- promulgation of the workplacestandard for lead.

The Department of Housing and -Urban Development (HUD) has re-quirments for reducing human expo-sure to lead through the prevention oflead poisoning from ingestion of paintfrom buildings, especially residentialdwelling. Their activities include (1)prohibition of the use of lead-basedpaints on structures constructed or re-habilitated through Federal fundingand on all HUD-associated housing; (2)the elimination of the immediatehazard from lead-based paint; (3) noti-fication of purchases of HUD-associat-ed housing constructed prior to 1950which may contain lead-based paint;,and (4) research activities to developimproved methods of detection andelimination of lead-based paint haz-.ards, and the nature and extent oflead poisoning.

The Consumer Product Safety Com-mission (CPSC) promulgated regula-tions in September 1977 which ban: (1)Paint and other surface coating mate-rials containing more than 0.06 per-cent lead; (2) toys and other articlesintended for use by children bearingpaint or other similar surface coatingmaterial containing more than 0.06percent lead; and (3) furniture coatedwith materials containing more than0.06 percent lead. These regulations


are based on CPSC's conclusion that Itis in the public Interest to reduce therisk of lead poisoning to young chil-dren from ingestion of paint and othersimilar surface-coating materials.

The Food and Drug Administration(FDA) adopted in 1974 a proposed tol-erance for lead of 0.3 ppm in evaporat-ed milk and evaporated skim milk.This tolerance is based on maintainingchildren's blood lead levels below 40 pgPb/dL FDA has also proposed anaction level of 7 pg Pb/ml for leach-able lead in pottery and enamelware,although the exact contribution ofsuch exposure to total human dietaryintake has not been established.

The Center for Disease Control(CDC) concluded in 1975 that undueor increased lead absorption existswhen a child has confirmed blood leadlevels of 30-70 pg Pb/dl or an EP ele-vation of 60-189 pg Pb/dl exceptwhere the elevated EP level Is causedby iron deficiency.

In developing the lead air standard,EPA has estimated both individualand population blood lead levels whichit regards as safe targets. The Agencybelieves that these targets do not nec-essarily serve as precedents for otherregulatory programs. There bre threereasons for this view:

(1) These targets were selected onthe basis of what the Clean Air Act re-quires. Other programs have other leg-islative requirements which would leadto adoption of different but equally le-gitimate goals.

(2) The scientific data provided bythe air quality criteria allow compari-son of air levels with blood lead levels,but analogous information Is not avail-able for other media. At this time,there does not appear to be the sameextent of information about theimpact on blood lead of lead in food.water, and nonfood ingested Items. Be-cause of this, FDA, CPSC and otherEPA standards have been based on es-timates of acceptable daily dose ratherthan on blood lead targets.

(3) Studies currently underway mayprovide new information relevant toestimating safe levels of lead exposure.

Commlrs Br Orn s FEAL AGscrrs

Comments on the proposed lead airquality standard were received fromeight Federal Agencies. Five of theAgencies endorsed the air standardwhile three of the Agencies comment-ed on specific Issues and neither en-dQrsed nor opposed the standard. TheCenter for Disease Control and theU.S Public Health Service voiced sup-port for the proposed standard of 1.5pg Pb/m and urged basing the deci-sion on the standard solely on consid-erations of public health. CDC Is fullysatisfied that EP elevation does indeedrepresent a subclinical manifestationof lead toxicity and that young chil-

46257

dren are the population most at rlikfrom lead exposure, while some sub-groups of children are at special riskto lead because of conditions such asmalnutrition, genetic factors,- or irondeficiency.

The Consumer Product Safety Com-mission endorsed the approach andsome of the Judgments made in arriv-ing at the proposed air standard.CPSC concurred with the positionthat children are the population at en-hanced risk to lead exposure, and thatthe goal of a mean population bloodlead level for children of 15 pg Pb/dl issufficiently low to be protective of thepopulation at enhanced risk of expo-sure. CPSC views the selection, of EPelevation as the adverse health effectof concern as open to challenge andsuggests basing the standard on amore generally recognized severehealth effecL CPSC condurs that thecontrbuton..of nonair sources to leadbody burden must be evaluated in set-ting the air standard and suggests thata larger nonair contribution, such as13.5 pg Pb/dl used in the Californiastandard. might be considered.

The Food and Drug Administrationcommended EPA's proposal of an am-bient air quality standard for lead.FDA agrees that children aged 1-5years old comprise the most criticallysensitive population. FDA concursthat 15 pg Pb/dl is a reasonable maxi-mum blood lead level to use as anaverage national goal for childrenaged 1 to 5, although FDA suggeststhat for young children the margin ofsafety is disturbingly narrow. The divi-sion of the 15 pg Pb/dI into 12 pg Pbhdl for nonair sources and 3 pg Pb/dlfor air sources was not unreasonablein FDA's view.

The Occupational Safety and HealthAdministration endorsed EPA's pro-posed standard for lead and agreeswith EPA that 15 pg Pb/dl as an aver-age national blood lead level goal foryoung children is reasonable. OSHAviews their proposed standard of 100pg Pb/m, 8-hour time-weighted aver-age, and their establishment, of 40 pgPb/dl as the threshold effect level forworkers as consistent with the EPAproposed standard.

The Department of Transportation(DOT) endorsed the proposed stand-ard of 1.5 pg Pb/m. Based on an anal-ysis of the impact of the proposedstandard on the highway program,DOT concluded that it is highly prob-able that transportation-related viola-tions of the proposed standard wouldbe limited to large urban areas.

In commenting on the proposedstandard,.the Department of the Inte-rior (DOI) expressed concern that theburden for meeting the proposedstandard will fall primarily on leadand copper smelters and battery man-ufacturers, and commented on the-


46258

impact of lead dustfall on groundwater quality. The Tennessee ValleyAuthority provided specific commentson the proposed State implementationplan regulations and the proposedFederal reference method. The De-.partment of Commerce offered com-ments on the potential impacts of thestandard, pointing out that more con-sideration should be given to the po-tential impact of the standard on thepetroleum industry.

THE FEDERAL REFERENCE METHOD

The reference method for the deter-mination of lead in suspended particu-late matter collected from ambient airdescribes the appropriate techniquesfor determining the concentration oflead and its compounds as measured aselemental lead in the ambient air. Atotal of eight organizations submittedwritten comments on the method andtwo persons made comments at EPA'sFebruary public hearing on the pro-posed air quality standard. Since pro-posal of the Federal reference methodfor lead, EPA has completed addition-al testing of the method and addednew information on the precision ofthe extraction analysis procedure.

Two of the commenters recommend-ed the addition of a nitric plus hydro-chloric acid extraction procedure. Theextraction procedure of the propbsedmethod contains only nitric acid.' Useof a mixed acid procedure wouldpermit the analyst to quantitativelyextract more metals than just lead,thereby allowing him to analyze thesame extract for more than one metal.The analysis for lead would not be af-fected. EPA agrees that a mixed acidextraction procedure should be added,and the revised method contains amixed nitric-hydrochloric acid extrac-tion procedure. -

- One commenter questioned the reli-ability of the air volume measured inthe sampling procedure because of dif-ferences between initial and final flowrates caused by buildup of particulatematter on the collecting filter. Themethod of sampling specifies that ini-tial and final flow rates must fall be-tween 40 and 60 cubic feet per fflinutePnd variations within this range causeonly a slight error. If- the flow ratespecification is not met, the 'sampleshould be voided. For these reasons,EPA believes the air volume measure-ment does not suffer unduly from in-accuracies.

A question was raised as to theeffect of variation in lead contentacross the filter of the collectedsample on lead analysis, since themethod calls for analysis of only onestrip or one-twelfth of the filter. Ourwork has shown that strips taken fromdifferent positions within the filtercan, on occasion, produce differentlead values, but the effect appears to


be significant only when samplingnear a heavily traveled roadway. Theproposed method recommends analyz-ing additional strips, when samplingnear a roadway, to minimize this error.

One commenter pointed out that theproposed sampling procedure does notcollect gaseous (organic) lead com-pounds and recommended that EPAconsider requiring the use of a methodfor monitoring gaseous lead.. As thecriteria document states, reported am-bient levels of gaseous lead a;e verylow and EPA has determined that theeffort required to carry out-the diffi-cult task of monitoring for ambientgaseous lead is not justified in view ofthe extremely low concentration.

It was pointed out in the preambleto the proposed method that otheranalytical prindiples would probablybe handled by provision for approvalof the' equivalent methods (40 CFRPart 53) proposed elsewhere in thisFEDERAL REGISTER. Two organizationssubmitted requests that alternatemethods (X-ray fluorescence andanodic stripping voltametry) for leadanalysis be declared equivalent to thereference method These requests willbe considered when the procedures fordetermining equivalency are promul-gated.

The final Federal reference methodis based on measuring the lead contentof suspended particulate matter onglass fiber filters using high volumesampling. The lead is then extractedfrom the particulate matter withnitric acid facilitated by heat or by a

-mixture of nitric acid and hydrochlo-ric acid facilitated by ultrasonication.Finally, the lead content is measuredby atomic absorption spectrometry.

The reference method specified forlead measures the lead for a singlesampling period by extraction of aportion of a high-volume glass fiberfilter used to collect particulatematter over a 24-hour period. Someagencies may prefer to compositefilter strips from a number of sam-pling periods and extract ahd-analyzeit for lead. This procedure is accept-able provided the Agency shows thatthe compositing procedure results inthe same average lead value as wouldbe obtained from averaging individualvalues.

Dated: September 29, 1978.DOUGLAS M. COSTLE,

Administrator.REFERENCES

Angle, C. R. and M. S. McIntire. Environ--mental controls and the decline of bloodlead. Arch. Environ. HIth. (in press.) 1977.

Azar, A., R. D. Snee, and K. Habibi. AnEpidemiologic Approach to Community AirLead Exposure Using Personal Air Sam-plers. Environmental Quality and Safety,Supplement Vol I-Lead 254-288 (1975).

Barltrop, D., C. D. Strehlow, J. Thornton.and J. S. Webb. Significance of high soil

concentrations for childhood lead burdens.Environ. Hlth. Persp. Expt. Iss. 7:76-84,1974.

Billick,. I. A. durran, and D. Shier. Presen.tation to the U.S. EPA Lead Subcommitteeof the Science Advisory Board, Washington,D.C., October 7, 1977,

Fine, P. R., C. W. Thomas, R. H. Suho R,E. Cohnberg, and B. A. Flashner. PedlatriaBlood Lead Levels A Study in 14 IllinoisCities of Intermediate Population. JAMA221:1475-1479, September 25, 1972.

Johanson. W. C, and . P. Luby. A Reporton a Study to Determine the Blood LeadLevels in Dallas Children. Dallas Health Do-partment, Dallas, Tex. 1972.

Johnson, D. E., J. B. Tillery, and R J. Pro-vost. Levels of platinum, palladium and leadin populations of Southern California. Envi-ron. Health Persp. 12:27-33, 1975.

Landrigan. P. J., S. H. Gehlbach, B. F. Rosenblum, J. M. Shoults, et al. Epidemic LeadAbsorption Near an Ore Smelter, The roleof particulate lead. New England J. Med.292:123-129, 1975.

Manton, W. I. Sources of Lead in Blood.Akch. Environmental Health, 32:149-150,1977. ,

Rabinowitz, M. B. Lead contamination ofthe biosphere by human activity. A stableisotope study, PhD Thesis, University ofCalifornia, Los Angeles, 1974, 120 pp.

U.S.* Environmental Protection Agency.Air Quality Criteria for Lead Office of Re-search and Development, Washington, D.C,20460. EPA-450/8-77-017, December 1977.

von Lindern, I. and A. J. Yankel, Presenta-tion to the Shoshone Heavy Metals ProjectCommittee by Idaho Department of Healthand Welfare, Boise, Idaho, September 4,1975.

Yankel, A. J. and I. von Lindern. TheSilver Valley lead study. The relationship ofchildhood lead poisoning and environmentalexposure. & Air Pollut. Cont. Ass., August1977.

40 CFR Part 50 is amended byadding a new § 50.12 and a new appen-dix G as follows:

§ 50.12 National primary and secondaryambient air quality standards for lead.

National primary and secondary am-bient air quality standards for leadand its compounds, measured as ele-mental lead by a reference methodbased on appendix G to this part, orby an equivalent method, aie: 1.5 mi-crograms per cubic meter, maximumarithmetic mean averaged over a cal-endar quarter.(Sees. 109, 301(a4 Clean Air Act as amended(42 U.S.C. 7409, 7601(a)).)

AXPENDIX G-RMassCE METHOD FOR T1EDETERMINATION OF LFAD IN SUSPENDED PAn.

TicULATE MA=TR COLLEcTED PRoM Amai-ENT Am

1. Principle and applicability.1.1 Ambient air suspended particulate

matter is collected on a glass.fiber filter for24 hours using a high volume air sampler,

1.2 Lead in the particulate matter is solu-bilized by extraction with nitric acid(HNO.), facilitated by heat or by a mixture

FEDERAL REGISTER, ,VOL. 43, NO., 194-THURSDAY, OCTOBER 5, 1978


of ENO and hydrochloric acid (HCl) facili-tated by ultrasonication.

1.3 The lead content of the sample isanalyzed by atomic absorption spectrometryusing an air-acetylene flame. the 283.3 or217.6 nm lead absorption line, and the opti-mum instrumental-conditions recommendedby the manufacturer.

1.4 The ultrasonication extraction withHNOJ/HC1 will -extract metals other thanlead from ambient particulate matter.

2. Rlange, sensitivity, and lower detectablieZimt. The values given below are typical ofthe methods capabilities. Absolute valueswill vary for individual situations dependingon the type of instrument used, the leadline, and operating conditions.

2.1 Range. -The typical range of themethod is 0.07 to 7.5 jg Pb/m 3 assuming anupper linear range of analysis of 15 jig/mland an air volume of 2,400 i 3.

2.2 Sensitivity. Typical sensitivities for a.1 percent change in absorption (0.0044 ab-sorbance units) are 0.2 and 0.5 jig Pb/ml forthe 217.0 and 283.3 nm lines, respectively.

2.3 Lower detectable limit (LDL)-. A typi-cal LDL is-0.07 jig Pb/m3!.The above valuewas calculated by doubling the between-lab-oratory standard deviation obtained for thelowest measurable lead concentration in acollaborative test of the method.(15) An airvolume of 2,400 m3 was assumed. '

3. Interferences, Two types of interfer-ences are possible: chemical and light scat-tering.

3.1 Chemical. Reports on the absence (1,2, 3, 4, 5) of chemical interferences faroutweigh those reporting their presence, (6)therefore, no correction for chemical inter-

. ferences is given here. If the analyst sus-pects that the sample- matrix Is causing achemical interferencl, the Interference canbe verified and correctedfor by carrying outthe analysis with and without the methodof standard additions.(7)

3.2 Light scattering. Nonatomi absorp-tion or light scattering, produced by highconcentrations of dissolved solids in thesample, can produce a, significant interfer-ence, especially at low lead concentrations.(2) The interference is greater at the 217.0'um line than at the 283.3 nm line. No Inter-ference was observed using the 283.3 nmline with a similar method.(1)

Light scattering interferences can, howev-er, be corrected for instrumentally. Sincethe dissolved solids can vary depending onthe origin of the sample, the correction maybe necessary,-especially when using the217.0 nm line. Dual beam instruments witha continuum source give the most accuratecorrection. A less accurate correctioncan beobtained by using a nonabsorbing lead linethat is near the lead analytical line. Infor-mation on use of these correction tech-niques can be obtained from instrumentmanufacturers' manuals. ,

If instrumental correction Is not feasible.the interference can be eliminated by use ofthe ammonium pyrrolidinecarbodithioate-methylisobutyl ketone, chelation-solvent ex-traction technique of sample preparation.(8)

4. Rrecision and bias.4.1 The high-volume sampling procedure

used to collect ambient air particulatematter has a between-laboratory relativestandard deviation of 3.7 percent over therange 80 to 125 Ag/rm.(9) The combined ex-traction-analysis .procedure has an averagewithin-laboratory relative standard devi-ation of 5 to 6 percent over the range 1.5 to15 jig Pb/ml, and an average between labo-

ratory relative standard deviation of Ito 9percent over the same range. These valuesinclude use of either extraction procedure.4.2 Single laboratory experiments -and

collaborative testing indicate that there Isno significant difference In lead recovery be-tween the hot and ultrasonic extraction pro-cedures.(l5)

S. Apparatu5.1 Sampling.5.1.1 High-volume sampler. Use and cali-

brate the sampler as described In reference10.

5.2 Analysis,5.21 Atomic absorption spectrophoto-

meter. Equipped with lead hollow cathodeor electrodeless discharge lamp.

5.2.1.1 Acetylene The grade recommend-ed by the instrument manufacturer shouldbe used. Change cylinder when pressuredrops below 50-100 pslg.

5.2.1.2 Air. Filtered to remove partcu-late, oil, and water.

5.2.2 Glassware. Class A borosilicateglassware should be used throughout theanalysis.

5.2.2.1 Beakers. 30 and 150 ml. graduated,Pyrex.

5.2.2.2 Volumetric flasks. 100-ni].5.2.2.3 Pipettes. To deliver 50. 30, 15. 8. 4.

2 .1 ml.5.2.2.4 Cleaning. All glassware should be

scrupulously cleaned. The following proce-dure~s sugested. Wash with laboratory de-tergent, rinse, soak for 4 hours In 20 percent(w/w) HNO,. rinse 3 times with distilled.delonized water, and dry in a dust freemanner.

5.2.3 Hot plate.5.2.4. Ultrasonication water bath, un-

heated. Commercially available laboratoryultrasonic cleaning baths of 450 watts orhigher "cleaning power," Le., actual ultra-sonic power output to the bath have beenfound satisfactory.

5.2.5 Template. To aid In sectioning theglass-fiber filter. See figure 1 for dimen-sions,

5.2.6 Pilzz cutter. Thin wheel. Thickness<lmm.5.2-7 Watch glass.5.2.8 Polyethylene bottles. For storage of

samples. Linear polyethylene gives betterstorage stability than other polyethylenesand is preferred.5.29 Paraflim "W".0 American Can Co.,

Marathon Products, Nennah. Wis., or equiv-alent.

6. Reagents.6.1 Sampling.6.11 Glass fiber filters. The specifica-

tions given below are Intended to aid theuser In obtaining high quality filters withreproducible properties. These specifica-tions have been met by EPA contractors.

6.1.L1 Lead content. The absolute leadcontent of filters is not critical, but lowvalues are, of course, desirable. EPA typical-ly obtains filters with a lead content of <75j9g/fllter.

It is Important that the variation In leadcontent from filter to fter, within a givenbatch, be small

6.1.1.2 Testing. .6.1.1.2.1 For large batches of filters

(>500 filters) select at random 20 to 30 fl-ters from a given batch. For small batches(<500 filters) a lesser number of filters maybe taken. Cut one 2/x8' strip from each

*Mention of commercial products doesnot Imply endorsement by the US. Environ-mental Protection Agency.

filter anywhere in the filter. Analyze allstrips, separately, according to the direc-tions in sections 7 and 8-

6.1.1.2.2 Calculate the total lead in eachfilter as

F Pbml x100 MI X 12 stripsFb= pg Pb/mI x 100T~ r 2l fitebstrp - f!ilter-

where:

Pb-Amount of lead per 72 square inches offilter, jig.

6.1.1.2.3 Calculate the mean. F., of thevalues and the relative standard deviation(standard deviation/mean x 100. if the rel-ative standard deviation is high enough sothat, In the analysts opinion, subtraction ofF. (section 10.3) may result in a significanterror In the pg Pb/m3- the batch should berejected.

6.1.124 For acceptable batches, use thevalue of Pb to correct all lead analyses (sec-tion 10.3) of particulate matter collectedusing that batch of flters. If the analysesare below the DL (section 2.3) no correc-tion is necessary.6.2 Anaysls.

6=1 Concentrated (15.6 A0 HNO ACSreagent grade HNO and commercially aval-able redistilled HNO. has found to have suf-fcliently low lead concentrations.

6.2.2 Concentrated (IL7 M) HCL ACSreagent grade.

6..3 Distilled-deionzed water. D.I.water).

6.4 3 At HNO. This solutlon is used inthe hot extraction procedure. To prepare,add 192 ml of concentrated HNO. to D.water in a I ! volumetric fssk. Shake wellcool and dilute to volume with DI. water./Caution: Nitric acid fumes are toxic. -Prepare n a well ventilated fume hood.

6.25 0.45 M HNO. This solution is usedas the matrix for calibration standardswhen using the hot extraction procedure.To prepare, add 29 ml of concentratedENO. to D.L water In a 1 1 volumetric flask.Shake well, cool, and dilute to volume withD.L water.

6a6 2.6 A HNOb+0 to 0.9 A HCL Thissolution Is used in the ultrasonic extractionprocedure. The concentration of HCI can bevaried from 0 to 0.9 .. Directions are givenfor preparation of a 2.6 Afr HO0.9 M HCIsolution. Place 167 ml of concentrated ENO.into a 11 volumetric flask and add 77 ml ofconcentrated HCI. Stir 4 to 6 hours diluteto nearly 1 I with D.L water cool to roomtemperature, and dilute to 1 L

6±9-7 OAOMHNO +XMrHCLThissolu-tion Is used as the matrix for calibrationstandards when using the ultrasonic extrac-tion procedure. To prepare, add 26 ml ofconcentrated HNO,, plus the ml of HC1 re-quired, to a 1 1 volumetric flask. Dilute tonearly 1 1 with D.I water cool to room tem-perature and dilute to 1 L The amount ofHC1 required can be determined from thefollowing equatio

Y 77m1 x 0.15x0.9 M

FEDERAL REGISTER, VOL 43, NO. 194-THURSDAY, -OCTOBER 5, 1978

46259.

46260where:

y - ml of concentrated HCI required.x - molarity of HCI in 6.2.6.0.15 = dilution factor in 7.2.2.

6.2.8 Lead nitrate, Pb(NO.).. ACS reagentgrade, purity 99.0 percent. Heat'for 4 hoursat 120" C and cool in a desiccator.

6.3 Calibration standards..6.3.1 Master standard, 1000 pg Pb/ml in

HNO,. Dissolve 1.598 g of Pb(NO.). in.0.45 MHNO, contained in a 1 1 volumetric flaskand dilute to volume with 0.45 M HNO .

6.3.2 Master standard, .1000 pg Pb/ml inHNO,/HCl. Prepare as in 6.3.1 except usethe, HNO./HCI solution in 6.2.7.

Store standards in a polyethylene bottle.Commercially availablecertified lead stand-ard solutions may also be used.

7. Procedure.7.1 Sampling. Collect samples for 24

hours using the procedure described in ref-erence 10 with glass.fiber fifters meeting thespecifications in 6.1.1. Transport collectedsamples to the laboratory taking care to.minimize contamination and loss ofsample. (17).

7.2 Sample preparation.7.2.1 Hot extraction procedure.7.2.1.1 Cut a %" x 8" strip from the ex-

posed filter using a template and a pizzacutter as described in figures land 2 Othercutting procedures may be used.

Lead in ambient particulate matter col-lected on glass fiber filters has been shownto be uniformly distributed across-the filter(1, 3, 11) suggesting that the position of thestrip Is unimportant. However, anotherstudy (12) has shown. that when sampling'near a road-way lead is not uniformly dis-tributed across the filter. The nonunifor-mity has been attributed to large variationsin particle size. (16) Therefore, when sam-pling near a road-way, additional strips atdifferent positions within the filter shouldbe analyzed.

7.2.1.2 Fold the strip in half twice and"place in a 150-ml beaker. Add 15 ml of 3 MHNO, to cover the sample. The acid shouldcompletely cover the sample. Cover thebeaker with a watch glass.

7.2.1.3 Place beaker on the hot-plate,contained in a fume hood, and boll gentlyfor 30 min. Do not let the sample evaporateto dryness. Caution: Nitric acid fumes aretoxic.

7.2.1.4 Remove beaker from hot plateand cool to near room temperature.

7.2.1.5 Quantitatively ' transfer thesample as follows:

7.2.1.5.1 Rinse watch glass and sides ofb eaker with D.I. water.

7.2.1.5.2 Decant extract and rinsings intoa 100-ml volumetric flask.

7.2.1.5.3 Add D.I. water to 40 ml mark onbeaker, cover with watch glass, and set asidefor a minimum of 30 minutes, This Is a criti-cal step _and cannot be omitted since itallows the HNO, trapped in the filter to dif-fuse into the'rinse water.

7.2.1.5.4 Decant the water from the filterinto the volumetric flask.

7.2.1.5.5 Rinse filter and beaker twicewith D.f. water and add rinsings to volumet-ric flask until total volumeois 80 to 85 ml.

7.2.1.5.6 Stopper flask and shake vigor-ously. Set aside for approximately 5 minutesor until foam has dissipated.

7.2.1.5.7 Bring solution to volume withD.I. water. Mix thoroughly.


7.2.1.5.8 Allow solution to settle for one.hour before proceeding with analysis.1 7.2.1.5.9 If sample is to be stored for sub-sequent analysis, transfer to a linear lpoly-ethylene bottle.

7.2.2 Ultrasonic extraction procedure.7.2.2.1 Cut a Y" x 8" strip from the ex-

posed filter as described in section 7.2.1.1.7.2.2.2 Fold the strip in half twice and

place in a 30 ml beaker. Add 15 ml of theHNO./HCl solution in 6.2.6. The acid shouldcompletely cover the sample,. Cover thebeaker with parafilm.

Th'e parafilm should be placed over thebeaker such that none of the paraflm Is incontact with water in the ultrasonic- bath.Otherwise, rinsing of the parafilm (section7.2.2.4.1) may contaminate the sample.

7.2.2.3 Place the beaker in the ultrasoni:cation bath and operate for 30 minutes.

7.2.2.4 Quantitatively transfer thesample as follows:

7.2.2.4.1 Rinse parafilm and sides ofbeaker with D.I. water.

7.2.2.4.2 Decant extract and rinsings intoa 100 ml volumetric flask.

7.2.2.4.3 Add 20 ml D.I. water to coverthe filter strip, cover with parafilm, and setaside for a minimum of 30 minutes. This is acritical step and cannot be omitted. Thesample is then processed as in sections7.2.1.5.4 through 7.2.1.5.9.

NoTE.-Samples prepared by the hqt ex-traction procedure are now in 0.45 M HNO,.Samples prepared by the ultrasonicationprocedure are in 0.40 M HNO + X M HCI.

8. Analysis. -8.1 Set the wavelength of the monochro-

mator at 283.3 or 217.0 nm. Set or alignother instrumental operating conditions asrecommended by the manufacturer.

8.2 The sample can be.analyzed directlyfrom the volumetric flask, or an appropriateamount of sample decanted into a sampleanalysis tube. In either case, care should betaken not to disturb the settled solids.

8.3 Aspirate samples, calibration stand-ards and blanks (section 9.2) into the flameand- record the equilibrium absorbance.

8.4 Determine the lead concentration inpg Pb/m, from the calibration curve, sec-tion 9.3.

8.5 Samples that exceed the linear cali-bration range should be diluted with acid ofthe same concentration as the calibrationstandards and reanalyzed.

9. Calibration.9.1 Working standard, 20 pg Pb/mi. Pre-

pared by diluting 2.0 ml of the masterstandard (6.3.1 if the hot acid extractionwas usedor 6.3.2 if the ultrasonic extractionprocedure was used) to 100 ml with acid ofthe same concentration as used in preparingthe master standard.

9.2 Calibration standards. Prepare dailyby diluting the working standard, with thesame acid matrix, as indicated below. "Otherlead concentrations may be used.

Volume of 20 Final volume. Concentrationpg/ml working ml pg Pb/mlstandard, ml

0 100 01.0 200 0.12.0 200 0.22.0 100 0.44.0 100 0.88.0 100 1.6

15.0 100 3.0,30.0 100 6.050.0 100 10.0

100.0 . 100 20.0

9.3 Preparation of calibration curve,Since the working range of analysis willvary depending on which le'ad line is usedand the type of instrument, no one set ofInstructions for preparation of a calibrationcurve can be given. Select standards .(plusthe reagent blank), in the same acid concen-tration as the samples, to cover the linearabsorption range indicated by the instru-ment manufacturer. Measure the absor.bance of the blank and standards as In sec-tion 8.0 Repeat until good agreementIs ob-tained between replicates. Plot absorbance(y-axis) versus concentration in pg Pb/ml(x-axis). Draw (or compute) a straight linethrough the linear portion of the curve. Donot force the calibration curve throughzero. Other calibration procedures may beused.

To determine stability of the calibrationcurve, remeasure-alternately-one of thefollowing calibration standards for every10th sample analyzed: concentration ;5 1lpgpb/!nl; copcentration 9 10 pg Pb/mi, Ifeither standard deviates by more than 5 per-cent from the value predicted by the cali-bration curve, recalibrate and repeat theprevious 10 analyses.

10. Calculation.10.1 Measured air volume. Calculate the

n easured air volume as

Qi + Qf

Vm = 2 xT

where:

V.,=Air volume sampled (uncorrected). m3.O1 =Initia air flow rate, m3/min.Qt=Final air flow rate, m3/min.T=Sampling time, min.

The flow rates QL and Q, should be cor-rected to the temperature and pressure con-ditions existing at the time of orifice call.bration as directed in addendum B of refer-ence 10, before calculation V..

10.2 Air volume at STP. The measuredair volume is corrected to reference 'condi-tions of 760 mm Hg and 25" C as follows.The units are standard cubic meters, sm3.

VSTP = V P 2 xT 1

Vnp=Sample volume, sm 3, at 760 um Hgand 298' K,

V,=Measured volumd from 10.1.P,=Atmosbherlc pressure at time of orifice

calibration, nun Hg.P,=760 mnm Hg.T =Atmospheric temperature at time of ori-

fice calibration, *K.T,=298" K.

- 10.3 'Lead concentration. Calculate leadconcentration in the air sample.

(ug Pb/ml x 100 ml/stri x 12 strps/fliter) - r bC-

FEDERAL REGISTER, VOL 43,-NO. 194-THURSDAY, OCTOBER 5, 1978

where:C=Concentration, jg Pb/sm'.jg Pb/ml=Lead concentration determined

from section 8.100 m /strip=Total sample volume.12 strips/filter=Useable filter area, 7" X 9"/

Exposed area of one strip, T" X 7".Fb=Lead concentration of blank filter, A±g,

from section 6.1.1.2.3.Vs-=Air volume from 10.2.

11. Quality control%" x 8" glass fiber filter strips containing

80 to 2000 pg Pb/strlp (as lead salts) andblank strips with zero Pb content should beused to determine if the method-as beingused-has any bias. Quality control chartsshould be established to monitor differencesbetween measured and true values. The fre-quency of such checks will depend on thelocal quality control program.

To minimize the possibility of generatingunreliable data, the user should follow prac-tices established for assuring the quality ofair pollution data, (13) and take part in

.EPA's semiannual audit program for lead-analyses.

12. Trouble shooting.1. Duiring extraction of lead by the hot ex-

traction procedure, it is important to keepthe sample covered so that corrosion prod-ubts-formed on fume hood surfaces whichmay contain lead-are not deposited In theextract.

2. The sample acid concentration shouldminimize' corrosion of the nebulizer. Howev'-er, different nebulizers may require joweracid concentrations. Lower concentrationscan be used provided samples and standardshave the same acid concentration.

3. Ashing 6f particulate samples has beenfound, by EPA and contractor laboratories,to be unnecessary in lead analyses by atomic


absorption. Therefore, this step was omittedfrom the method.

4. Filtration of extracted samples, toremove particulate matter, was specificallyexcluded from sample preparation, becausesome. analysts have observed losses of leaddue to filtration.

5. If suspended solids should clog the ne-bulizer during analysis of samples, centri-fuge the sample to remove the solids.

13. Authority.(Sees. 109 and 301(a). Clean Air Act as

amended, (42 U.S.C. 7409. 7601(a)).)14. References.1. Scott, D. R. et al. "Atomic Absorption

and Optical Emission Analysis of NASN At-mospheric Particulate Samples for Lead."Envir. ScL and Tcch., 10, 877-880 (1976).,

2. Skogerboe R. K. et al. "Monitoring forLead in the Environment" pp. 57-66. De-partment of Chemistry, Colorado State Uni-versity, Fort Collins, Colo. 80523. Submittedto National Science Foundation for publica-tions, 1976.

3. Zdrojewskl, A. et al "The AccurateMeasurement of Lead In Airborne Particu-lates." Inter. . Envfron. Anal Chem., 2, 63-77 (1972).

4. Slavin, W., "Atomic Absorption Spec-troscopy." Published by Interscence Com-pany, New York. N.Y. (1968).

5. Kirkbright, G. F., and Sargent. M.."Atomic Absorption and Fluorescence Spec-troscopy." Published by Academic Press.New York. N.Y. 1974.

6. Burnham, C. D. et at. "Determinationof Lead in Airborne Particulates In Chicagoand Cook County, IlL by Atomic AbsorptionSpectroscopy." Envir. SdL and Tech., 3, 472-475 (1969),

7. "Proposed Recommended Practices forAtomic Absorption Spectrometry." AS.TM

46261

Book of Standard% part 30. pp. 1596-1608(July 1973).

8. Koirttyohann, S. R. and Wen. J. W."Critical Study of the APCD-MIBK Extrac-tion System for Atomic Absorption." AzaLChem., 45, 1986-1989 (1973).

9. Collaborative Study of ReferenceMethod for tMe Determination of SuspendedParticulates in the Atmosphere (HighVolume Method). Obtainable from NationalTechnical Information Service, Departmentof Commerce, Port Royal Road, Springfield,Va. 22151, as PB-205-891.

10. "Reference Method for the Determina-tion of Suspended Particulates In the Atmo-sphere (High Volume Method)." Code ofFederal Regulations, Title 40, Part 50, Ap-pendix B. pp. 12-16 (July 1, 1975).

11. Dubois. L,, et al., "The Metal Contentof Urban Air." JAPCA, 16, 77-78 (1966).

12. EPA Report No. 600/4-77-034. June1977. "Los Angeles Catalyst Study Sympo-slum." Page 223.

13. Quality Assurance Handbook for AirPollution Measurement System. Volume I-Principle& EPA-600/9-76-005, March 1976.

14. Thompson, R. J. et al, "Analysis of Se-lected Elements In Atmospheric ParticulateMatter by Atomic Absorption." Atomic Ab-sorption Newsletter. 9, No. 3. May-June1970.

15. To be published. EPA, QAB, EMSL,RTP, N.C. 27711

16. Hlrschler, D. A. et at, "ParticulateLead Compounds in Automobile ExhaustGas." Industrial and Engineering Chemis-try, 49, 1131-1142 (1957). -

17. Quality Assurance Handbook for AirPollution Measurement Systems. VolumelI-Ambfent Air Specific Methods. EPA-600/4-77/027a May 1977.

[FR Doc. 78-28050 Filed 10-4-78; 8:45 am]


RULES AND REGULATI6NS

WDTIfOFGROOVEI a

Figure I

FEDERALREGISTER, VOL 43, NO. 194--THURSAY, OCTOBER 5, 1978

'46262


STRIPS FOR -OTHER ANALYSES 9 .

% xl" STRFIP FORLEAD ANALYSIS

Figure 2


[6560-01]

S FRL 937-6]

PART 51-PREPARATION, ADOP-TION, AND SUBMITTAL OF IMPLE-MENTATION PLANS

Implementation Plans for LeadNational Ambient Air Quality

Standard'

AGENCY: Environmental ProtectionAgency.ACTION: Final rulemaking.

SUMMARY: The regulations promul-gatecd below, together with the currentrequirements of 40 CFR Part 51, setforth the requirements for States tofollow in developing, adopting, andsubmitting acceptable implementationplans for the lead national ambient airquality standards (NAAOS'), ,promul-gated elsewhere in the FEDzEA REGIS-TEa. The implementation plans are re-quired under section 110 of the CleanAir Act. Amendments to the existingregulations for implementation plansare necessary because lead differsfrom other pollutants for which theexisting regulations were designed.The amendments address the follow-ing topics: definitions of point sourceand control strategy; control strategyrequirements; and air quality -surveil-lance.

EFFECTIVE DATE: This rulemakingis effective October 5, 1978; State im-plementation plans for lead are due byJuly 5, 1979.

ADDRESSES: U.S. EnvironmentalProtection Agency, Office of Air Qual-ity Planning and Standards, ControlPrograms Development Division (MD15), Research Triangle Park, N.C.27711.FOR FURTHER INFORMATIONCONTACT:

Joseph Sableski, Chief, Plans Guide-lines Section, at the above address or

'at 919-541-5437 (commercial) or 629-5437 (FTS).

SUPPLEMENTARY INFORMATION:

L BACKGROUND

On December 14, .1977, EPA pro-posed regulations for the' preparation,adoption, and submission of imple-mentation plans to achieve the nation-al ambient air quality standards forlead, which were also proposed'on thatsame date (42 FR 63087). EPA invitedcomments from interested persons andheld a hearing on the proposedNAAQS and State implementationplan (SIP) regulations on February 15and 16, 1978. EPA received commentson the proposed lead implementation'plan requirements from 25 corn-

menters. Of these, there were 10 rep-resentatives from industry, 9 fromState and local governmental agencies,4 from citizens' organizations and pri-vate citizens, and 2 from" other federalagencies.

2. allMMARY oF COXmiNTs ANDRESPONSES

The following.discussion summarizesmost of the comments rebeived on theproposal. Thdre were a few other com-ments that EPA felt were not signifi-cant to warrant discussion in the FED-ERAL REGISTER and that did not affectthe final regulation. A siummary of allthe comments received and EPA's-re-sponse is available for public inspec-tion during normal business hours inEPA's Public Information ReferenceUnit (PM 215), 401 M Street SW.,Washington, D.C. 20460, telephone202-755-0707.

2.1 POINTSOTRCE DEFINITION

There were several comments con-cerning the definition- of a pointsource. One commenter indicated that.the definition of a point source is con-fusing and differs from that- used inthe provisions in the Clean Air Act'concerning prevention of significantdeterioration (PSD). Parts of thatcomment were directed toward the ex-isting definition of point source in§ 51.1(k), which, as the commenter ac-knowledged, is not the subject of theproposal -and will not be discussedhere.

Currently, § 51.1(k) defines pointsources in terms of emissions per yearand location of the source, as well as alisting of individual source categories.Currently, point sources of other pol-lutants for which NAAQS' exist thatare located in urban areas are definedas those that emit pollutants'in excessof 100 tons per year; point sources inless urbanized areas are defined asthose that emit pollutants in excess of25 -tons per 6r. In light of the lowlevel of the lead standard in relationto the other standards (e.g., for partic-ulate matter), good reason exists todefine point sources for lead at a lowerlevel of emissions than that for thecurrent get of pollutants for whichEPA has established NAAQS'. Basedon art analysis contained in EPA's"Supplementary Guidelines for LeadImplementation Plans," (1) EPA is de-fining a point source of lead as "anystationary source causing emissions in

- excess of 4.54 metric- tons (5 tons) peryear of lead or lead compounds meas-ured as elemental lead." This repre-sents a slight change from the propos-al, which failed to account for leadcompounds.

The significance of the definition of§51.1(k) is that the emission inven-tory, which is used to determine theextent of possible violations of the air

quality standard and determine the ef-fectiveness of control strategies, mustinclude a determination of emissionsfrom each point source. All emissionsfrom sources other, than point sourcesmay be grouped together as area (orline) sources.

The definition of point source,which was intended to be based onactual emissibns, differs from the defi-nition in section 169 of the Clean AirAct (which pertains to prevention ofsignificant deterioration), which isbased on potential emissions. Thereason for the difference Is that forplanning purposes, the inventory ofexisting sources must be based on anactual situation to be used as a base-line upon which one develops a plan.For new source review (includingreview for prevention of significant de-terioration), one must be aware of theemissions that could be emitted fromthe proposed source as well as actualemissions;'hene, the source size crite-

_ria for selection of new sources to bereviewed under the recently promul-gated PSD regulations incorporate po-tential, as well as actual, emissions.The definitions of point source in§ 51.1(k) for all pollutants have beenrevised from the proposal to clarifythat the size criteria are based uponactual emissions. This implies theemissions that are emitted after anycontrol is applied.

2.2 - CONTROL STRATEGY

A number of persons provided com-ments concerning the control strategyaspects of the proposed regulations.

One commenter correctly noted adiscrepancy between the list of sourcecategories in §§ 51.80 ("Demonstrationof attainment"), and 51.84 ("Areasaround significant point sources"), forwhich the State must perform an anal-ysis. The lists should have been identi-cal-§ 51.84(a) should have also includ-ed lead-acid storage battery manufac-turing plants that produce 1,200 ormore batteries per day. The rulemak-ing promulgated below incorporatesthis change. The criterion for produc-tion of batteries, which was based on amonthly standard, has been raised to2,000 batteries per day, however, to ac-count for the slightly less stringentquarterly lead ambient standard.

Several commenters indicated thatthe requirements in §§ 51.83 ("Certainurbanized areas") and 51.85 ("Otherareas") appeared Identical and there-fore one of the sections was redun-dant. The difference between the twosections lies in the required geographi-.cal scope of the analysis. Section 51.83requires that the plan contain an anal-ysis of each urbanized area that has ameasured lead air concentration thatis in excess of 4.0 lg/m3 ,quarterlymean (monthly mean in the proposal).The distinguishing provision is that

FEDERAL REGISTER, VOL 43, NO 194-THURSDAY, OCTOBER 5, 1978

46264

the nysis must cover at least theentire urbanizecd area. Section 51.85,on the other hand, requires that. forany area (ur6anized or not) with a. re-corded lead concentration that doesnot meet the national standard of 1.5jig/m 3 quarterly mean (monthly meanin the proposal), the plan-must con-tain an analysis of at least the area inthe vicinity of the monitor that has re-corded the concentration. Therefore,the analysis may be restricted to anevaluation of only those sourceswithin a relatively small radius fromthe monitor.

Several commenters suggested thatthe control. strategy requirementsinsure that the burden for solving thelead air problem be equitably dIstrib-tited between mobile and stationarysources. The commenters realized thateither kind of control is expensive anddifficult to implement. 'In response,EPA maintains that the allocation ofthe burden of control in the SIP is theprimary responsibility of the States,and therefore EPA will avoid setting,criteria in 40 CFR 51 that favor con-trol of one source category over an-other. EPA acknowledges that meas-ures that are expensive and difficult.to implement may have to be adoptedin order to demonstrate attainment ofthe lead standard.

Two commenters indicated that theregulations did not provide a satisfac-tory treatment to problems related tobackground concentration. Theyclaimed that a facility in an area ofhigh background concentrations maybe unduly penalized in efforts toattain the standard. -EPA acknowl-edges that this problem may exist. Inmost cases, however, the high back-ground air concentrations are general-ly due to other sources in the vicinity.It is the primary responsibility of theState to-allocate the burden of emrmis-sion control to the various sourcescausing the problem. Sources will havean opportunity to comment on theplan at the public hearing that is re-quired before the plan is submitted toEPA.

One commenter suggested that EPArecommend analysis of fugitive dustand on-premise soil before a State ini-tiates a program of prolonged moni-toring in the vicinity of gray ironfoundries, As mentioned in the pream-ble to the proposed regulations. EPAidentified gray iron foundries ashaving the potential for causing viola-tions of the national standard for lead,but this identification was based onlimited data, concerning the amount. offugitive emissions from the facilities.Although EPA does not feel that thedegree of confidence in this identifica-tion justifies a requirement for Statesto. analyze all gray iron foundries (of.which- approximately 1.500 exist), EPAencourages States to consider analysis.


of these sources to the extent thattime and resources permit. The com-menter'es suggestion concerning theanalysis of fugitive dust and on-prem-ise soil before undertaking extensivemonitoring and analysis, appears tooffer the potential for conservingscarce resources In that States maywant to restrict. their monitoring andanalysis efforts to those plants withrelatively high lead levels In dust andsoil.

The same commenter also Indicatedthat secondary lead smelters and simi-lar sources probably cannot be mod-eled because of fugitive dust and low

-stacks. EPA recognizes the difficultyn quantifying fugitive dust and fugi-

tive emissions and recognizes that lowstacks will generally cause higher con-centrations closer to the stack than,will higher stacks. The Clean Air Actrequires that an approved plan mustdemonstrate attainment of the stand-ard, however. EPA has, based uponpreliminary analyses, determined, thatsecondary lead smelters and othersources listed n § 51.84 have the po-tential for causing violations of thelead standard. EPA also believes thatattainment of the lead standardaround such sources can best be dem-onstrated by the use of an atmospher-ic dispersion model. In many cases,States will not have the time or re-sources to perform detailed studies toquantify the fugitive dust and fugitiveemissions from individual facilitiesand may have to rely on factors thatwere based on limited studies of otherfacilities or best estimates. In comply-ing with § 51.84, for cases where noambient lead data. were collected inthe vicinity of the source and where aState must thus estimate the air qual-ity impact of the sources, the Statewill have to decide for Itself what levelof control Is warranted by the confi-dence in the data upon which theanalysis is based.

In another comment concerningmodeling, one commenter from a Stateagency claimed that the models usedfor assessing the monthly impact ofpoint sources are not accessible tomost. air pollhtion control agencies. Inthe initial analysis of the impact ofthe proposed standard on pointsources, It is true that EPA used theOak Ridge National Laboratory model,"Atmospheric Transport and Disper-sion'Model" (ATM), (2) which is prob-ably not available to most agencies.That analysis was revised subsequent-ly, and another model was used, how-ever. Also, EPA is recommending theuse of other models, specifically thosemodels for particulate matter de-scribed in EPA's "Guideline on AirQuality Models," (3) for modelingpoint sources for SIP development.These models are generally available.

46265

The same commenter Indicated thatonly ambient monitoring or upwind-downwind sampling can give a reliableassessment of the impact of sourceswith a. large fugitive emission compo-nent. EPA acknowledges that monitor-Ing studies generally give a more reli-able estimate of the air quality impactof sources that emit fugitive emissionsbecause no estimate need be made ofthe fugitive emissions, which are diffi-cult to measure directly. Such studiescannot be done for many areas withinthe time and resource constraintsfacing the States. however, and there-fore EPA regulations require the useof modeling around such pointsources. States will have to make esti,-mates of the fugitive emissions basedon whatever information may exist.EPA Is, however, in another part ofthis Ftn~mAI R=sur giving advancenotice of proposed rulemaking to re-quire the Installation of ambient moni-tors In the vicinity of three categoriesof point sources that have major fugi-tive emisons-Primary and secondary.lead smelters and primary coppersmelters. Presumably, after thesemonitors have been n place for a fewyears, the data. yielded will. providemore accurate information concerningthe nature and magnitude of the leadproblem from these sources. Afterthose data become available_ EPA mayrequire States to revise their imple-mentation plans, Purthermore. EPAintends to develop fugitive lead emis-sion factors that are more accuratethan those that currently exist.

One commenter recommended thatthe regulations place the proof of com-pliance with emission regulations onthe stationary source. The commenterclaimed that local enforcement agesn-cies do not have the funds for continn-ous monitoring. In response, EPA hasfound that there are no techniques forcontinuous monitoring of lead emis-sions. The State will be required underexisting regulations C40 CPR 5L19) tocarry out a source surveillance pro-gram which generally consists ofvisual Inspection of the installation ofcontrol equipment and testing pf stackemissions.

Several comments addressed issuesconcerning control of lead in gasoline.One commenter indicated that any re-duction of the lead content of gasoline-or any other simflarkinds of programs(presumably meaning control of fuelsor the control of lead emissions fromindividual vehicles) that may beneeded In the SIP over and above thecurrent Federal program should bedone through Federal rather thanlocal regulation. EPA has alreadytaken steps to control the amount oflead In gasoline through the phase-down of lead in leaded gasoline andthe requirement that cars equippedwith catalyst mufflers must burn un-

FEDERAL REGISTER, VOL 43; NO. 194-THURSDAY, OCTOBER S, 1978

46266

leaded gasoline. The level of control oflead Ii leaded gasoline was based onaverage conditions concerning lead airquality concentrations. Areas thathave unique problems and that willfind It hpossible to demonstrate at-tainment of the lead standard throughstationary source control or throughtransportation control measures mayhave to adopt measures such as re-quirements for further reduction oflead in gasoline or control of leademissions from the tailpipe of vehicles.Currently, EPA does not foresee theneed for additional mobile source con-trol strategies and does not intend torequire further, nationally applicablelead-in-gasoline reductions.

Other comments concerning furtherreductions of the lead conteft of gaso-line suggested that such reductions beundertaken only after -sufficient datais available to indicate that the leadair quality problem is geographicallybroad enough and only after a findingthat such a limitation is necessary toachieve a national ambient air qualitystandard. The 'comnenters enumer-ated the problems with instituting fur-ther control of the lead content of gas-oline. The commenters contended that*application of more stringent locallimitations of lead in gasoline Could se-riously disrupt the nation's gasolinedistribution system, resulting in severespot shortages, especially during thesummer months when gasolinedemand Is at Its highest.

EPA recognizes this problem and ad-vises the States to consider the com-ment. Also, under section 211(c)(4)(C)of the Clean Air Act, EPA will not ap-prove State or regional-programs forfurther reductions of. lead content ofgasoline unless the State demonstratesthat no other reasonable measures areavailable.

Also, two of the commenters recom-mended that 40 CFR Part 51 regula-

"tions be modifed to reflect the restric-tions in section 211(c)(4)(C) of the Actregirding State limitation of the leadcontent of gasoline. In response, EPAhas Incorporated the intent of the Actinto the definition of "control strate-gy' as it pertains to restrictions onfuel additives.

Two commenters representing pri-mary lead smelting companies recom-mended an alternative approach toprotecting the'health of persons fromthe ambient lead levels in the vicinityof primary lead smelters. They recom-mended that sources that cannot con-trol emissions so that the lead. stand-ard will be met be allowed to conduct apublic health screening and hygieneprogram aimed at reducing theamount of lead that children in the vi-cinity of the source take in and insur-ing that safe blood lead levels are sat-isfactorily maintained.


EPA believes that there are legal,technical, and equity problems withthe programs that render it unaccep-table as the sole means of implementa-tion of the national standard for lead.

Concerning the legal problem, sucha program assumes that the air qual-ity standard will be violated, and pre-sumably, the plan will not contain ademonstration that theair qualitystandard will be attained. Under theClean Air Act, EPA must disapprove aplan that does not contain a demon-stration that the air quality standardwill be attained by the mandatory at-tainment date. The Act provides forthe protection of health through thestandard setting, planning, and'imple-mentation processes; it does not allowfor a surrogate procedure wherebypublic health may be protected eventhough the ambient standards are notmet..

Concerning technical problems, therelationship between emissions from asource and blood lead levels is notquantitatively certain. Even assuminga biological monitoring system were tobe established, it is unclear what thesource would have to do concerning itsoperation or emissions if the monitor-ing program revealed unacceptableblood lead levels. Even if a course ofaction were clear, the damage wouldhave already been done, while thebasic purpose of the standard settingand implementation process envi-sioned by section.110 of the Act is pre-vention of public health problems.

Concerning equity, the biologicalmonitoring program would inconve-nience the very people that are sup-posed to benefit from the Act. Rhe Actenvisioned that all' people have anequal right to healthy air. The com-menters who recommended that bio-logical monitoring approach apparent-ly believe that people -who happen tolive in areas with elevated lead levelsshould not be accorded equal protec-tion, but should be made to pay extrafor their health through presumablycontinuous participation in a bloodsampling program. If-a person -did notwant to participate, it is doubtfulwhether he could be forced to, sotherefore his health could be placed injeopardy.

One commenter representing a pri-mary lead smelter warned that enclo-sure of smelter operations to controlfugitive lead emissions may present a

_severe occupational health hazard toemployees who must work within theenclosed space. EPA realizes these po-tential problems. If a source installssuch enclosures, it must of course alsomeet any applicable regulations setforth by the Occupational Safety andHealth Administration as well as con-trol emissions to the extent specifiedin the applicable implementation plan.

One other commenter expressedconcern that there appears to be noth-ing that can be done in areas where asource is dmploying best available con-trol technology, yet the standard Isstill not being met. The Act requiresthat for approval, an Implementation

,plan must demonstrate that the con-trol strategy contained in the plan isadequate to attain and maintain theNAAQS. EPA realizes, however, that aplan which meets this criterion may,even after full implementation, not ac-tually result in attainment by the at-tainment date. This would gererally,indicate that assumptions concerningthe amount of emissions and the rela-tionship between emissions reductionsand air concentrations that were madewhen the plan was developed eventu-ally were proven erroneous. If an ap-proved plan Is later found to be Inad-equate to attain the standard, EPAwill require the State to revise theplan. If that plan has already requiredall measures short of those that wouldforce significant source closures, EPAwill at that time decide whether theclosure must be effected or whetherthere are alternatives to this in thediscretion given to EPA under the Actin sections 110 or 113. States shouldmake every effort to develop andsubmit plans that demonstrate attain-ment of the tandard u~ing the bestdata available.

Several commenters from State airpollution control agencies indicatedthat the development of lead SIP'swill be difficult within the timeframeprovided. EPA realizes that the devel-opment of the lead plans will be com-peting in priorities and resources withthe development of plan revisions bytitle I, part D, of the Clean Air Act fornonattainment areas. Where a Stateneeds additional assistance In the de-velopment of Its lead plan, or where ItIs unsure as to the priority of develop-ment of its lead plan, the State shouldconsult with the appropriate EPA re-gional office.

2.3 AIR QUALITY MONITORING

Several commenters recommendedthat a minimum number of samples betaken to determine whether the stand-ard is being attained. Also, several per-sons commented that the samplingshould be performed more frequently,such as daily. One person indicatedthat determination of the attainmentstatus should be done by annualrather than monthly averaging. -Atleast a 3-month average would be moredesirable. Another person indicatedthat the shorter the averaging period,the more the number of samplesshould be.

Concerning the minimum number ofvalid samples needed to determine anaverage, it is general practice to re-quire at least 75 percent of the sched-

FEDERAL REGISTER, VOL 43, NO. 194--THURSDAY, OCTOBER 5, 1978


uled samples to be valid. EPA will pre- major roadways for the peak concen-pare a guideline on this and. other tration site was 5 to 15 meters. Theissues concerning the determination of "intent was to sample ambient air toattainment of the. standard. Concern- which significant portions -of the pop-ing the frequency of sampling, EPA Is ulation are being exposed over thepromulgating a national ambient. air averaging time of the standard.quality standard for lead in this FtD- During a typical day, even the most

iAL REGISR that is based on a calen- susceptible population group does notdar -quarter, rather than calendar spend more than one-half of theirmonth. as had been proposed. EPA has time In the amblent. air below the 2-determined that a sampling schedule meter level or within 15 meters of aof once every 6 days -is adequate to major roadway. They are indoors or atgive a representative sample for a considerable- distances from roadwaysquarter. for the remainer of their time. Conse-

One commenter indicated that moni- quently, requiring samplers to betoring the inner city area. should be placed below 2 meters above thegiven top priority because the vehicle ground or, closer than 5 meters to amix ir these areas favors older cars roadwa would lead to concentrationthat burn leaded gasoline. EPA's re- measurements that would be unrepre-sponse is that if maximum exposures sentative of lead exposures. Further.occur in these areas, then monitoring some range of heights and distances isthese areas should in fact receive first necessary due to practicalities involvedpriority. The determination of accept- in finding suitable sites, power avail-ability of the sites will be the joint re- ability, protection against vandalism,sponsibility of the States and the cog- allowing free pedestrian movementnizant EPA regional office; along sidewalks, etc.

One commenter recommended that One commenter recommended thatEPA change the recommendation in the criteria for monitoring In the vi-the draft "Supplementary Guidelines cinity of roadways not include specificfor Lead Implementation Plans" (1) distance restrictions, such as the re--for locating- lead monitors near road- quirement. for placement of monitorsways that are at or below grade level between S and 15 meters from therather than near elevated roadways. traffic lane. The commenter ndicatedThe commenter suggested that the that many areas do not have housingguideline require measurements to be that close to major roadways andrepresentative of emissions and envi- therefore the numerical restrictionsronmental exposure. The commenter would be counterproductive to Insur-indicated that- the proposed guidance ing accurate monitoring of maximum

- would exclude monitoring play areas population exposure EPA's responsethat are located. beneath elevated is that even though housing may notroadways. EPA agrees with this coin- exist "that close toz roadways in allment. The purpose behind excluding cases, the public has access to manybelow grade level monitoring and mo- such areas.itoring near elevated roadways was to One commenter recommended thatinsure adequate exposure at the mont- the monitoring guidelines requiretaing site. If significant population monitoring lead below ground level Inexposures consistent with the averag- public places such as subway stationsing time of the KAAQS were encoun- and underground shopping areas. Intered in these situations, then mont- response, EPA's monitoring guidancetoning in these locations would meet was, written for purposes of determin-the intent'of the guidance. EPA has ing attainment of a standard. Locatingrevised the siting guidance to account monitors in subways to determine ex-for these considerations. posures would be considered special

SeveraI comments were directed purpose monitoring and thus could betoward the recommended location of a performed' if desired by the State ormonitor at a given location. Two per- local agency. EPA however, does notsons indicated that the allowance of 5 feel that monitors placed in thesesitu-meters in elevation of lead air moni- ations would yield data suitable for de-tors is too high and that it should be veloping implementation plans or de-changed or should allow for numerical termining national trends and stfate-adjustment of the data. One person gies and thus will not require It. Fur-suggested that the monitors be re- thermore, since no member of thequired to be placed closer to roadways public spends more than perhaps 8because he felt that would be more hours out' of 24 hours In such loca-representative of exposure; another tions, monitoring there would not besuggested that the monitors are re- representative of population exposureqcuired to be placed too close to the for a standard based upon 24-hourstreet already in some cases and that sampling for an'entire quarter.the data from the monitors, would be One- commenter recommended thatunrepresentative. -EPA proposed a the regulations require ambient mont-range of heights for lead monitors toningin the: vicinity of major pointfrom 0 to 5 meters above ground level, sources. Not, doing so may allow poten-The proposed reqjuired distance from tially significant public health Impacts

46267

that result from fugitive emissions atmajor point sources to be ignored. Asmentioned above, in another part ofthis F rmra. REor , EPA is givingadvance notice of proposed rulemak-ing to modify the regulations to re-quire source owners or operators tomonitor In the vicinity of primary andsecondary lead smelters and primarycopper smelters. EPA chose thesesource categories because they areconsidered to have the potential forcausing the greatest' concentrations ofair lead in their vicinity and becausethe nature and magnitude of their fu-gitive emissions are relatively un-known compared to other source cate-gories. The regulations will continueto vest authority In the regional ad-ministrators to require monitors in thevicinity of other sources. EPA will pre-pare guidance concerning the recom-mended number and siting of monitorsin the vicinity of lead point sources.

Another conmenter claimed thatthe regulations do not adequately ad-dress-the locations where air qualitysamples will be taken and at what dis-tance from a facility they will betaken. As mentioned above. EPA willdevelop guidance on the placement oflead monitors In the vicinity of pointsources. The guidance for locatingmonitors elsewhere is highly specificIn that the distances from obstruc-tions and interferences are quantita-tively described Itis not possible froma national perspective, however, to de-velop general regulations that wouldcover every concelvable situation thatcould occur without; making the regu-lations unduly complex.

One commenter suggested that thelead monitors should not be requiredto be permanent until the State hasmore experience in sampling and mon-Itoring lead. Also, several commentersrecommended that EPA require initialmonitoring by mobile vans or otherprocedures to locate the most criticalsites. EPA does not intend that; the re-quired monitoring stations- wouldremain at one place in perpetuity.EPA does, however, need some stabif-Ity in monitoring site locations toallow for trends analysis. If a stationonce established is later found to beunrepresentative, it should be movedto anew location. EPA agrees with theintent of the comments and hasalways encouraged special purposemonitoring prior to establishing a per-manent monitoring station. EPA willnot require resource-intensive proce-dures to locate critical sites, however.

SeveraI commenters recommendedthat the regulations require morethan a minimum of two. monitors perarea. EPA's response is that the regu-latiors do not preclude placing outmore than two monitors. EPA is inter-ested nationally In obtaining onlyenough data to establish a data trend,

FEDERAL REGISTER,, VOL 43, NO. 1941--THURSDAY, OCODER 5, 1978

46268

determine if the Federal programsthat result in the reduction of auto-mobile lead emission are causing de-creases in lead air concentrations, anddetermine the approximate attain-ment status of areas. Furthermore,the regulations would allow EPA to re-quire additional monitors on a; case-by-case basis where EPA believes thattwo monitors are insufficient to deter-mine whether the national standard isbeing attained and maintained.

,One of the commenters who recom-mended that the regulations requiremore than two monitors per area ob-jected to placing responsibility on theEPA regional offices to require addi-tional monitors and determine their

.location. The commenter claimed thatthis precludes both accountability ofthe State's actions arid public partici-pation. EPA's response is that requir-ing a limited number of samplers spe-cifically to meet data needs at the na-tional level and leaving the determina-tion of the number and location of theremaining stations in the State .net-work to the State and the regionaloffice is consistent with the recom-mendations of EPA's Standing AirMonitoring Work Group(SAMWG). (4) In a recent action (43FR 34892, published Aug. 7, 1978),EPA proposed that the locations ofstations (for'all pollutants) need notactually be-included in the implemen-tation plan, but the plan must containa monitoring program which includesa monitoring network that is basedupon negotiations between the Stateand the EPA regional office. The planwould also have to contain a commit-ment to annually review the adequacyof the network and to establish new

'stations and relocate or terminat6 ex-isting stations as needed in order tokeep the network responsive to dataneeds. EPA feels that if the entiresystem were part of the SIP, the onlyway the State could make modifica-tions would be to propose the change,hold a public hearing, and submit thechange to EPA as a plan revision. EPAwould then have to propose to approvethe revision, entertain public com-ment, and then finally promulgate itsapproval. EPA feels that this processis too time-consuming and woulddefeat the purpose of the annualreview, which is to make timely adjust-ments to the network. Also, EPA feelsthat the potential benefits fr6m thisprocess would be too few to warrantits implementation. The proposed re-quirements concerning air qualitymonitoring, however, would requirethat the locations of the monitors beavailable at all times for public inspec-tion. Therefore, when the State re-vises its SIP in order to implement theforthcoming air quality monitoring re-quirements, the public can at thattime comment on the State system.


The public can also comment onchanges to the networks at any timeby submitting written comment onchanges to the State or EPA regionaloffice.

One commenter indicated that thelowwolume sampler compares favor-ably in measurement with the high-

'volume sampler, which is the refer-ence 'method for collection of thesample, and excludes larger particlesthat are not respirable and which thecommenter' feels- are not significantfrom a health standpoint. The com-menter implies that EPA should allowthe use of the low-volume sampler.Low-volume sampling will be allowedif the agency that wishes to use itdemonstrates that the method isequivalent to the reference method,using the procedures that EPA is pro-posing in another portion of this FED-ERAL REGISTER.

3.0 -OTHER CHANGES FROM PROPOSAL

3.1 AIR QUALITY SURVEILLANCEREQUIREMENTS

EPA has revised the air quality sur-veillance requirements for lead slight-ly from the proposal to render themclearer and more consistent with thegeneral air quality surveillance re-quirements currently under revision

- that will apply to all pollutants. Theserevised general requirements willclosely follow and implement the rec-ommendations of EPA's Standing AirMonitoring Work Group. (4) The sig-nificant revisions of the lead require-ments from the proposal include thefollowing A change of the date bywhich the entire monitoring systemmust be established; deletion of thereferences to the terms, "National AirQuality Trends ' Stations" . (or"NAQTS") (which are now called "Na-tional Air Monitoring Stations") (or"NAMS") and "State and Local AirMonitoring Stations" (or "SLAMS").These terms have not yet been definedby regulation, so referenice to them ismeaningless. Modification to the re-quirement that the plan contain a de-scription of the monitoring system;and revision of the "SupplementaryGuidelines on Lead ImplementationPlans" to account for locatiQn of moni-toring stations in urban street can-yons.

As mentioned in the preamble to theproposal, EPA will eventually incorpo-rate the lead monfitoring requirementsinto' the air quality monitoring re-quirements that apply to all pollut-ants for which NAAQS' exist.

3.2 REPORTING OF DATA BASE

Under the proposal in § 51.86(c), theState would have been required tosubmit the air quality data collectedsince 1974 in the format of EPA's stor-age and retrieval of aerometric data

(SAROAD) system. The final regula-tion below retains this requirement,but provides the regional administra-tor with the authority to waive the re-quirement concerning the format ofthe data.

3.3 LISTS OF URBANIZED AREAS

There were several errors in the twotables of areas in the preamble to theproposal. In table 2, "Urbanized areaswith lead air concentrations exceedingor equal to 1.5 ug/m 3, maximummonthly mean (1975)", the Norfolk,Va. AQCR number should have read223 instead of 233. Table 3, "Urbanizedareas with lead air concentrationsequal to or exceeding 4.0 jg/m3, maxi-mum monthly mean (1975)" shouldhave read as follows:

"AQCR Urbanized area

15. ... Phoenix. Ariz.24.............Los Angeles-Long Beach. Calif.29 .................. San Diego. Calif.30 .................. San Francisco-Oakland. Calif.30 .................. San Jose. Calf.67................ Chicago, Ill1-northwestern Indiana.215 ................ Dallas, Tex.

SOURCE: Data from EPA's EnvironmentalMonitoring Support Laboratory, Statisticaland Technical Analysis Branch."

These corrections, however, are nowacademic, since the averaging time ofthe lead standard Is now quarterly.Therefore, tables 2 and 3 are revisedto reflect the quarterly average. Table2 (renumbered table 1) appears at theend of the preamble. Table 3, revisedto reflect the quarterly average, nowcontains only one area, the Los Ange-les-Long :peach, Calif., urbanizedarea. The list reflects only the datacurrently available to EPA, and gener-ally the quarterly averages availableare not truly representative due to in-sufficient data. There are other dataavailable to State and local air pollu-tion control agencies, however, thatmay Indicate that other areas haveconcentrations in excess of the concen-trations specified in the criteria forperforming the analysis.

3.4 EXAMPLE LEAD CONTROL STRATEGY

The preamble to the proposal indi-cated that EPA was developing an ex-ample lead control strategy to assistthe States in developing their lead Im-plementation plans. The preamble in-dicated that the example was sched-uled for completion by March 1978.Because EPA has received an exten-sion for promulgating the nationalambient air quality standard for lead,because the 'example control strategywould be based on the final implemen-tation plan regulations promulgatedbelow, and because of other delays,the example controls strategy will



probably not be available until Novem-ber or December of 1978.

4.0 REFERENCES

1. "Supplementary Guidelines for LeadImplementation Plans." U.S. EnvironmentalProtection Agency, Office of Air QualityPlanning and Standards, Research TrianglePark, N.C. 27711. (OAQPS No. 1.2-104).

2. CulkowskL W, M. and M. R. Patterson,"A Comprehensive Atmospheric Transportand Diffusion ModeL" (ORNL/NSR/EATS-17. Oak Ridge National Laboratory, OakRidge, Tenn., 1976.

3. "Guideline on Air Quality Models."Monitoring and data Analysis Division,Office of Air Quality Planning and stand-ards, U.S. Environmental ProtectionAgency, Research Triangle Park, N.C. EPA-450/2-78-027 (OAQPS No. 1.2-080). April,1978.

4. "Air Monitoring Strategy for'State Im-,plementation Plans." Prepared by the,Standing Air Monitoring Work Group. U.S.Environmental Protection Agency, Office ofAir and Waste Management, Office of AirQuality Planning and Standards, ResearchTriangle Park, N.C. 27711. EPA-450/2-77-010. June, 1977.

TABLE 1-Urbanized Areas With Lead AirConcentrations Exceeding or Equal to 1.5pg/m, Maximum QuzrterZy Mean (1975)

AQCR No. Area +

004 -_ Birmingham Ala.015 -. Phoenix. Arli.031 - Fresno, Ca.024 - Los Angeles-Long Beach, Calif028.. Sacramento, Calif.024......... San Bernardino-Riversde, Calif.029- San Diego. Calif.030...... San Franclsco--Oakland, Calif.030 - San Jose, Calif.036 Denver, Colo.043. New York, N.Y.-northeastern New

Jersey.042 - Waterbury. Conn.042 -. Springfield, Chicopee-Holyoke,

Mass--Connecticut045 -. Wilmington, DeL-New Jersey.045 -. Philadelphia Pa.-New Jersey.047 -. Washington. D.C.-Maryland-Vlrgin-

I a.067 - Chicago. I-northwestern Indiana.131 - Minneapolis--t Paul, Minn.070 -. St. Louis Mo.-lnoLs.013__- Ias Vegas. Nev.148 __ Reno, Nev.184. . Oklahoma City. Okla.151. Scranton Pa.244 - San Juan. P.R.200= Columbia. S.C.202 - Greenville, S.C.207 - Knoxville, Tenn.018 - Memphis. Tenn.-Mlsslssippl.-215. Dallas. Tex.153- El Paso. Tex.216 -_ Houston, Tex.

SouRcE: Data from EPA's EnvironmentalMonitoring Support Laboratory, Statisticaland Technical Analysis Branch.

Dated: September 29, 1978.DOUGLAS AE COSTLE,

Administrato'.The Code of Federal Regulations,

Title 40, Chapter I, Part 51; is amend-ed as follows:

1. In § 51.1, paragraph (k) is revisedand paragraph (n) is amended byadding paragraph (11) as follows:

§ 51.1 Definitions.

(k) 'Toint source" means the follow-Ing.(1) For particulate matter, sulfur

oxides, carbon monoxide, hydrocar-bons, and nitrogen dioxide-(i) Any stationary source the actual

emissions of which are in excess of90.7 metric tons (100 tons) per year of

•the pollutant In a region containing anarea whose 1970 "urban place" popula-tion, as defined bF the U.S. Bureau ofthe Census, was equal to or greaterthan 1 million;

(ii) Any stationary source the actualemissions of which are in excess of22.7 metric tons (25 tons) per year ofthe pollutant in a region containing anarea whose 1970 "urban place" popula-tion, as defined by the U.S. Bureau ofthe Census was less than 1 million; or

(II) Without regard to amount ofemissions, stationary sources such asthose listed in appendix C to this part.(2) For lead, any stati6nary source

the actual emissions of which are inexcess of 4.54 metric tons (5 tons) peryear of iead or lead compounds meas-ured as elemental lead.

* S S S S

(n) ...(11) Control or prohibition of a fuel

or fuel additive used In motor vehicles,if such control or prohibition is neces-sary to achieve a national primary orsecondary air quality standard and isapproved by the Administrator under§ 211(c)44)(C) of the Act.

2. Section 51.12, paragraph (e) Isamended by adding subdivision (3) asfollows:

§ 51.12 Control strategy: General.

* S S S S

(e) ...(3) This paragraph covers only plans

to attain and maintain the nationalstandards for particulate matter,sulfur oxides, carbon monoxide, pho-tochemical oxidants, hydrocarbons,and nitrogen dioxide.

3. Section 51.17 Is amended by (1) re-vising the heading to read "Air qualitysurveillance: Particulate matter, sulfuroxides, carbon monoxide, photochemi-cal'oxidants, hydrocarbons, and nitro-gen dioxide," and (2) adding para-graph (d) as follows:

§51.17 Air quality surveillance: Particu-late matter, sulfur oxides, carbon mon-oxide, photochemical oxidants, hydro-carbons, and nitrogen dioxide.

S • • * S

(d) This section covers only plans toattain and maintain the nationalstandards for particulate matter,sulfur oxides, carbon monoxide, pho-tochemical oxidants, hydrocarbons,and nitrogen dioxide.

4. A new § 51.17b is added as follows:

§ 51.17b Air quality surveillance:. Lead.(a) This section covers only plans to

attain and maintain the nationalstandards for lead.

MONITORING IN CERTAIn ARiAs

(b) The plan must provide for the es-tablishment of a monitoring systemthat contains at least two permanentlead ambient air quality monitoringstations in each urbanized area (as de-fined by the U.S. Bureau of the.Census)-(1) That has a 1970 population

greater than 500,000; or(2) Where lead ir quality concentra-.

tions currently exceed or have exceed-ed 1.5pg/m 3 quarterly arithmetic meanmeasured since January 1, 1974.(c) The EPA Regional Administrator

may specify more than two 'monitoringstations If he finds that two stationsare insufficient to adequately deter-mine If the lead standard Is being at-tained and maintained. He may alsospecify stations in areas outside theareas covered In paragraph (b) of thissection.(d) The monitoring system must con-

tain at least one roadway type moni-toring site and at least one neighbor-hood site and be sited in accordancewith the procedures specified in EPA's"Supplementary Guidelines for LeadImplementation Plans."(e) The monitors must be operated

on a minimum sampling frequency ofone 24-hour sample every 6 days.(f) Existing sampling sites being

used for sampling particulate mattermay be designated as sites for sam-pling lead if they meet the siting crite-ria of "Supplementary Guidelines forLead Implementation Plans.!"

Cg) The plan must provide that alllead air quality monitoring stationswill be established and operational asexpeditiously as practicable. but nolater than 2 years after the date of theAdministrator's approval of the planfor the stations specified under para-graph (b) of this section.(h) The analysis of the 24-hour sam-

ples may be performed for either indi-vidual samples or composites of thesamples collected over a calendarinonth or quarter.(1) [Reserved3

FEDERAL REGISTER, VOL 43, NO. 194-THURSDAY, OCTOBER 5, 1978 -

46269

46270

REquzaamrETs APPLICABLE TO ALLMONITORS

(j) The plan must provide for havinga description of the system availablefor public inspection and submissionto the Administrator at- his request.The description must be available at

* all times after the date the plan ismade available 'for public inspection.The description must include the fol-lowing Information:

(1) The SAROAD site identificationform.'(2) The sampling and analysis

method.(3) The sampling schedule.(k) The monitoring method used in

any station in the monitoring systemsrequired in this section must be a ref-erence or equivalent method for leadas defined in § 50.1 of this chapter.

5. A new subpart E is added as fol-lows:

Subpart E-Contral Strategy: Lead

See.51.80 Demonstration of attainment.51.81 Emissions data.'51.82 Air quality data.51.83 Certain urbanized areas. I51114 Areas around significant point

sources.51.85 Other areas.51.86 Data bases.51.87 Measures51.88 Data availability.

Aumoarry: Sees. 110, 301(a), -Clean -AirAct as amended (42 U.S.C. 7410; 7601).

Subpart E-Control Strategy: Lead

§ 51.80 Demonstration of attainment.(a) Each plan must contain a demon-

stration that the standard wil be at-tained and maintained in the follow-ing areas: -

(1) Areas in the vicinity of the fol-lowing point sources of lead:

Primary lead smelters.Secondary lead smelters.Pnimary copper smelters.Lead gasoline additive plants.Lead-acid storage battery manufacturing

plants that produce 2,000 or more batteriesper day.

Any other stationary source that actuallyemits 25 or more tons per year of lead orlead compounds measured as elementallead.

(2) Any other area that has lead airconcelntrations in excess of the nation-al standard concentration for lead,measured since January 1, 1974.

(b) The plan must demonstrate thatthe measures, rules, and regulationscontained in the plan are adequate toprovide for the attainment of the na-tional standard for lead within thetime prescribed by the Act and for themaintenance of that standard for areasonable period thereafter.

(c) The plan must include the fol-lowing-


(1) A summary of the computations,assuniptions, and Judgments used todetermine the reduction of emissionsor reduction of the growth in emis-sions that will result from the applica-tion of the control strategy.

(2) A presentation of emission levels.expected to result fromapplication ofeach measure of the control'strategy. '

(3) A presentation of the air qualitylevels expected to result from applica-tion of the - overall control strategypresented either in tabular form or asan isopleth -map showing expectedmaximum concentrations.

§ 51.81 Emissions data.(a) The plan must contain a sum-

mary of the baseline lead emission in-ventory based upon measured emis-sions or. where measured emissionsare not. available, documented emis-sion factors. The point source inven-tory on which the summary is basedmust contain all sources that emit 5 ormore tons of lead per year. The inven-tory must be summarized In a formsimilar to that shown in appendix D.

(b) The plan must contain a sum-mary of projected lead emissions for- "

(1) At least 3 years from thedate bywhich EPA must approve or disap-prove the plan if no extension undersection* 110(e) of the Clean Air Act isgranted;

(2) At least 5 years from the date bywhich EPA must approve or disap-prove the plan if an extension is re-quested'under section 110(e) of theClean Air Act; or

(3) .Any'-other longer period If re-quired by the appropriate EPA, Re-gional Administrator.

(c) The plan must contain a descrip-tion of the method used to projectemissions.

(d) The plan must contain an identi-fication of the sourdes of the dataused in the projection of emissiond.

§ 51.82 -Air quality-data.(a) The plan must contain a sum-

mary of all lead air quality data meas-ured since January 1974. The plan'must include an evaluation of the datafor reliability, suitability for calibrat-ing dispersion models (when suchmodels will be used), and representa-tiveness. When possible, the air qual-ity data used must be for the same ba-seline year as for the emission inven-tory.

(b) If additional lead air quality dataare desired to determine lead air con-centrations in areas suspected of ex-ceeding the lead national ambient airquality standard, the plan may includedata from any previously collected fil-.ters from particulate matter highvolume samplers. In determining thelead content of the filters for controlstrateg, demonstration purposes, aState may use, in addition to the refer-

ence method, X-ray fluorescence orany other method approved by the Re-gional Administrator.

(c) The plan must also contain a tab-ulation of, or isopleth map showing,maximum air quality concentrationsbased upon projected emissions.

§ 51.83 Certain urbanized areas.For urbanized areas with measured

lead concentrations in excess of 4.0pg/m., quarterly mean measured sinceJanuary 1, 1974, the plan must employthe modified rollback model for thedemonstration of attainment as aminimum, but may use an atmosphericdispersion model if desired.

§ 51.84 Areas around significant pointsouirces.

,(a) The plan must contain a calcula-tion of the maximum lead air qualityconcentrations and the location ofthose concentrations resulting fromthe following point sources for thedemonstration of attainment:

Primary lead smeltermSecondary lead smelters.Primary copper smelters.Lead gasoline additive plans.Lead-acid storage battery manufacturing

plants that produce 2,000 or more batteriesper day.

Any other stationary source that actuallyemits 25 or more tons 'per year of lead orlead compounds measured as elementallead.

(b) In performing this analysis, theState shall use an atmospheric disper-sion model.

§ 51.85 Other areas.For bach area In the vicinity of an

air quality monitor that has recordedlead concentrations In excess of thelead national standard concentration,the plan must employ the modifiedrollback model as a minimum, but mayuse an atmospheric dispersion model ifdesired for the demonstration 'of at-tainment.

§ 51.86 Data bases.(a) For interstate regions, the analy-

sis from each constituent State must;where practicable, be based upon thesame regional emission inventory andair quality baseline.

(b) Each State shall submit to theappropriate EPA Regional Office withthe plan, but not as part of the plan,emissions data and information relat-ed to point and area source emissionsas Identified in the "SupplementaryGuidelines-for Lead ImplementationPlans:'

(c) Air quality data.(1) Each State shall submit to the

appropriate EPA Regional Office withthe plan, but not as part of the plan,all lead-air quality data measuredsince JanUary 1, 1974. This require-



nient does not apply if the data has al-ready been submitted.

(2) The data must be submitted inaccordance with the procedures anddata forms specified in chapter 3.4.0 ofthe "AEROS User's Manual" concern-ing storage andretrieval of aerometricdata (SAROAD) except where the Re-gional Administrator waives this re-quirement.

§ 51.87 feasures.(a) The lead control strategy must

include the following:(1) A description of each control

measure that is incorporated into thelead plan.

(2) Copies of or citations to the en-forceable laws and regulations to im-plement the measures adopted in thelead plan.

(3) A description of the administra-tive procedures to be used in imple-menting each selected control meas-ure.

(4). A description of enforcementmethods Including, but not limited to,procedures for monitoring compliancewith each of the selected controlmeasures, procedures for handling vio-lations, and a designation of agency re-sponsibility for enforcement or imple-mentation.

§ 51.88 Data availability.(a) The State shall retain all de-

tailed data and calculations used inthe preparation of the lead analysesand plan, make them available forpublic inspection, and submit them tothe Administrator at his request.

(b) The detailed data and calcula-tions used in the preparation of thelead analyses and control strategiesare not considered a part of the leadplan.(Secs. 110, 301(a), Clean Air Act as amended(42 U.S.C. 7410.7601).)

CFR Doc. 78-28051 Filed 10-4-75: 8:45 am]


46271

Documents

(,1 2 1/,1(...rules for the development of State im-plementation ' plans promulgated under 40 CFR Part 51, and an advance notice of proposed rulemaking under 40 CFR Part 51 for ambient