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Docket Number: 

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Jl--

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

SCIENCE ADVISORY BOARD 

CLEAN AIR SCIENTIFIC ADVISORY COMMITTEE 

LEAD EXPOSURE SUBCOMMITTEE 

Open Meeting 

United States Environmental Protection Agency 

Mall Level, Conference Room North 3 

401 M Street, Southwest 

Washington, D. C. 20460 

Tuesday, October 25, 1988 

9:30 a.m. 

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•••" 2 3 

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A P F ••' [•.-. A R A N L- b. o 

DR. TIMOTHY LARSON, Chairman 

Envi ronmep-ital Engi neer i ng and Science Program 

Department oi Ci vi 1 E:"igineer i ng 

U n i v e r s i t y CP f W a s h i n g t 'D n 

A. ROBERT FLAAK, Executive Secretary 

Envi r onment a1 Sc i en t i st 

Sc i ence Ad vi sor y Bo ar pd 

United States Envir c> n m enta 1 P r o t e >::: t i o n Age n c y 

Member s >:;pf t he Subc <:>mmi 11 ee 

DR. J. JULIAN CHISOLM, JR 

Associate Professor 

Johns. Hopkins School of 

Medi ci ne 

DR. SCOTT CLARK 

Professor of Environmental 

Health 

Department of Environmental 

Health 

University of Cincinnati 

Medical Center 

DR. IAN von LINDERN 

President 

Terragraphics Environmental 

Engineering 

DR. KATHRYN R. MAHAFFEY 

S c i e n c e A d v i s o r 

0 f f i c e o f t h e D i r ec t or 

Nationa l Institut e cif 

E n v i r onmen t a1 Health 

Sc i ences 

DR. PAUL MUSHAK 

Consultant and Adjunct 

Pr ofessor 

Uni v e r s i t y o f N a r t h C a r o 1 i n a 

DR. MICHAEL. B. RABINOWITZ 

Invest i gatc«r 

Marine Biological Laboratory 

DR. ROBERT D. ROWE 

Seni'^r Vice President 

RCG/Hagler, Reilly, Inc. 

E'^rii.ci.gants Jrom Environmental. E'£*ii?£ilon Agency 

JEFF M. COHEN JOHN H. HAINES 

Office of Air Quality Planning Office of Air Quality Planning 

and Assessment and Assessment 

DR. ROBERT W. ELIAS 

EnviriDnmental Criteria and 

Assessment Office 

EXECUTIVE COURT REPORTERS 

DR. DAVID W. McLAMB 

Office p;'f Air Quality Planning 

and Assessment 

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01 h e r s P r s s e n t 

DR. ALLAN H. MARCUS 

Battelle Memorial Institute 

JAMES GILCHRIST, ESQUIRE 

R e pre sent i n g the Ame r ic an 

Mining C ong r e ss 

GALE HOFFNAGLE 

TRC: En v i r PDnment a 1 Consu11 ant s 

EDWARD SEEGER, ESQUIRE 

R e p r e s e n t i n q L e a d In cl u s t r i e H 

Assoc i at i on 

JOHN YODER 

L e a d Ind u s trie s A s s o c i a t i o n 

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"ABLE OF CObH'ENTS 

WELCOME AND INTRODUCTION 

Dr. Timothy Cohen, Chairman 

OPENING REMARKS 

A. Robevt Flaak, Executive Secretary 

OVERVIEW OF DRAFT DOCUMENT AND SUBCOMMITTEE COMMENTS 

M r . J o h n H a i n e s 

Mr. Jeff M. Cohen 

PUBLIC COMMENTS AND GENERAL DISCUSSION*' 

Public Comments: Gale Hoffnagle, TRC 

E nv i ronmental Consu11 ants 

CASE STUDY RESULTS AND DISCUSSION 

Mr. Jeff M. Cohen 

Dr. David W. McLamb 

A. Robert Flaak 

CHAIRMAN'S SUMMARY 

GENERAL DISCUSSION 

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PROCEEDING S 

CHAIRMAN TIMOTHY LARSON: We will call the meeting 

tin order. 

This is the Subcommittee of CASAC meeting on Lead 

Exposure. 

WELCOME AND INTRODUCTION 

CHAIRMAN LARSON: I would welcome everybody here. 

We are glad to have a distinguished group of people t>:p be 

able to review the Exposure Draft document. 

I would like f>:>r everyone to introduce themselves 

briefly, including anybody in the audience who would like to. 

My name is Tim Larson. I am the Chairman of this 

Subcommittee. I am in the Environmental Engineering and 

Sciences Program at the University of Washington. I am also 

a member of CASAC. 

As the one leading the charge here, so to speak, I 

am relying on the particular expertise we have here on lead. 

So I am very interested in people's comments. 

DR. CHISOLM: I am Julian Chisolm. I am from 

Baltimore, interested in lead poisoning. 

DR. von LINDERN: I am Ian von Lindern from 

Moscow, Idaho. I have worked on lead smelters. 

DR. MAHAFFEY: I am Kate Mahaffey from National 

Institute of Envir-rmmental Health Sciences. 

DR. McLAMB: I am Dave McLamb with the 

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1 Environmenta l Protectio n Agency , Offic e iinf Air Qualit y 

2 Planning and Standards. I do related documents on lead 

3 NAAQS, fi^r instance regulatory impact analyses and those 

4 analyse s which buil d it. 

5 MR. HAINES : I am John Haine s with th e Offic e of 

6 Air Qualit y Plannin g and Standards . I work with Jeff with 

7 respect to the NAAQS review. 

8 MR. COHEN : I am Jeff Cohen . I work with John 

9 Haines. 

10 [Laughter D 

11 DR. MARCUS : Allen Marcus , Battelle , Researc h 

12 Triangl e Park, Nort h Carolina . I am consultan t to Offic e of 

13 Air Qualit y Plannin g and Standards . 

14 DR. CLARK : Scott Clark , Universit y of Cincinnati ; 

15 involved in lead studies and soil abatement. 

16 DR. RABINOWITZ : I am Michae l Rabinowitz . I am a 

17 geochemis t at Children' s Hospital in Boston . 

18 DR. MUSHAK: Paul Mushak, consultant, adjunct 

19 faculty at the University of North Carolina. 

20 DR. ROWE : I am Bob Row e wit h RCG/Hagler , Bailly ; 

21 and I'm a chemist . 

22 MR. FLAAK: I am Bob Flaak. I am the Executive 

23 Secretar y of CASAC . By training , I am a marin e ecologist , 

24 but by inclination I have been doing this for a long time. 

25 Member s of th e audience , woul d yo u mind 

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introducin g y •-• u r s e 1 v e s b r i e f 1 y ? 

DR. EL IAS : I ' m Rob E1 i a.s, En v i v on ment a 1 Cr iteri a 

a nd Assessmen t Offic e a t RTP. 

M R. Y 0 D E R: I ' m J o h n Y o d e r f r o m L e a d I n d u s t r i e s 

Assoc i a t i on . 

MR. HDFFNAGLE: Gale Hoffnagle, TRC Environmental 

C'Dnsul tants. 

MR. SEEGER: Ed Seeger, attorney fp:>r Lead 

Industr i es Associ ati on. 

MR. GILCHRIST: I am Jirn Gilchrist, attorney for 

the American Mining Congress. 

OPENING REMARKS 

MR. FLAAK: I have a couple of opening remarks, 

brief1y. 

The larger microphones in front of you are the 

ones for the speaker system; the smaller ones are the ones 

for the Court Reporter. If you have something to emphasise, 

don't pull up the Court Reporter's microphone up to you 

because she will jump right out of her chair. 

[Laughter] 

This particular Subcommittee is a Subcommittee 'I'f 

the Clean Air Scientific Advisory Committee. Normally, our 

subcommittees are chaired by a member of the full CASAC, 

which Dr. Larson is: one of the seven statutory members. 

The purppipse of this Subcommittee review is tpip 

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review a draft document that was completed back in August p.:in 

the Lead Exposure Analysis, Methodology and Validation. This 

document has been reviewed by the Committee. 

Comments have been submitted to the Agency and 

these comments are part of the discussion for a good part of 

this discussion for today. 

When Mr. Cohen gets into his remarks, he will 

explain a little further why we are doing this and what we 

hope to get out of it. 

For the purposes of those members on this panel 

who have not been with us before, we operate in the public 

eye under the Federal Advisory Committee Act. All of our 

meetings are held in the public. 

Most of the CASAC meetings are fully transcribed 

and copies of the transcription are available usually about 

two weeks after the meeting. 

For any handout material or other documents that 

you don't manage to get a copy of while you are here today, 

please advise me. I wi11 see that you get a copy some time 

after the meeting. 

Tim, do you have anything else? 

CHAIRMAN LARSON: No, not at this time. 

MR. FLAAK: We will turn it over to John. 

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OVERVIEW OF DRAFT DOCUMENT AND SUBCOMMITTEE COMMENTS 

dLi . sE°.b.Q dli.Q H 

MR. HAINES: I would like to begin by thanking the 

Subcommittee for their comments. They proved most helpful to 

us. I specially appreciate the time spent preparing them. 

As you ans all aware, the? Exposure Analysis is a 

key component of our ongoing review of the Lead NAAQS. You 

may recall, the Environmental Protection Agency first set the 

NAAQS for lead in 1978. 

Under the Clean Air Act, the Environmental 

Protection Agency is required to periodically review all 

National Air Quality Standards and the underlying health 

criteria on which they are based. 

As you know, in 1986 the Environmental Criteria 

and Assessment Office completed the update and revisiions to 

the Air Quality Criteria for lead, and CASAC closed on that 

document in August 1986. 

In early 1986, we prepared a draft of our staff 

paper which went before CASAC. As part of that session, 

CASAC ampong other things recommended that the staff refine 

its lead exposure methodology and conduct appropriate 

validati on. 

As the result of those recommendations, we have 

produced the draft report that is in front of you today for 

review and comment. 

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Also because we view this document as important we 

have asked Bob and the SAB and CASAC to put together a 

Subcommittee that could specifically focus in 'on the-? exposure 

methodology and validation work. We think it's important 

that this receive a very thorough review. 

This will hopefully place us in a posit i'on that we 

can move ahead and pull together the next draft of the staff 

paper, and be able to base our projections off the 

methodology set forth here. 

Just for the point of view of the audience, the 

comments submitted by the Subcommittee members have been 

placed in the Docket. So they are available to you folks if 

you would like to review them. 

To facilitate today's discussion, Jeff will 

provide a brief overview of how the exposure methodology 

relates to the NAAQS review. Then he will proceed to provide 

a review of the Subcommittee's comments. 

We have tried to group those comments into major 

categories and our responses to them. So you can see 

collectively what the group's comments were and how we place 

to address them. 

As shown on the agenda, this afternoon Jeff will 

present for the Subcommittee's information some initial 

results from two case studies we have done. There will be an 

opportunity to discuss those briefly. 

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1 At the end of the day after Jeff and Dave McLamb, 

2 we will out line.some of the related activities. Jeff will 

3 talk ab'out some other potential applications for the model 

4 outside our immediate program; Dave will talk about how it 

5 will fit into our regulatory impact analysis and that work. 

6 Finally, I want to reiterate that Allan Marcus has 

7 been working very closely with Jeff and the staff on the 

8 development of the exposure model. Bob Elias has provided 

9 invaluable input tp;i us as well. 

10 Are you ready to go, Jeff? 

11 MR. COHEN: Okay. 

12 Mr_._ Jgf_f_ M._ Cohen 

13 MR. COHEN: Again, I want to thank you all for the 

14 comments. We were hoping for the level of detail we actually 

15 received. It will be very useful to us in finalizing the 

16 report. 

17 I want to start out by looking at the Lead Air 

18 Standard review process. You can see where the lead exposure 

19 modeling fits in and where our report is t'l-day. You can als o 

20 see the different points of CASAC review. 

21 For example, here at the criteria document 

22 assessment there is a review of the benefit s analysis 

23 methodology about a year ago. We are planning on going to 

24 CASAC with a draft staff paper in early 1989. 

25 This paper will incorporat e results of the lead 

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exposure modeling and also fold in the overall health risk 

assessment. The staff paper will then serve as a basis fcvr 

t h e r e c ID m m e n d a t i o n s t o t h e A d m i n i s t r a t o r o n a 11 e r n a t i v e 

standards. 

There s h o u 1 d b e a n o t h e r a r r o w here, a c t u a 11 y, f r ci m 

the case study blood-lead estimates to the benefits analysis. 

We will talk about that at the end '~'f the clay. 

Just to remind us all, unlike the other criteria 

air pollutants that we have to review, lead has established 

itself in many different pathways of exposure. So it is a 

unique exposure problem for us. 

We need to develop different kinds of exposure 

methodologies. 

This summarizes the different methods that we have 

develpi-ped, all accounting for air and well as non-air 

sources, especially rich in future trends in gasoline and 

di et. 

The disaggregate model combines separate 

relationships between blood lead and lead in diet, soil, dust 

as well as air lead from the literature. It is adopted from 

the criteria document. 

We made some changes to reflect newer data. Like 

the aggregate model, it assumes a blood-lead equilibrium with 

historical exposures. 

While the disaqqreqate model has an air blood-lead 

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level that really reflects pretty much inhalation, the 

ag g r eg at e mode1 s1 ope includes effec t s of ind i rect a i r 1ead 

exposure: dust and sp;:'i 1 . 

The uptake biokinetic model uses age-specific 

intakes 'Dn a daily basis from each pathway, as well as agespecific absorption factors. Blood-lead and tissue-lead 

levels are governed by a linear biokinetic m^Ddel whose growth 

and metabolic factors change with age. 

One of the advantages we see in the model is that 

it can explicitly estimate the effects.of relatively rapid 

changes. 

One of the features of the biokinetic uptake model 

is that it requires a large variety of assumptions in input 

data. This lists the parameters that we discuss in the 

report. 

We note, just as background, which ones appear to 

be strongly influential in predicting children's blood leads. 

Those are the ones on which we conducted various sensitivity 

analyses. 

Again, just to remind us, given the available data 

the models estimate average exposure conditions. We are 

concerned not only with the mean blood lead, but with upper 

percentiles of blood leads. 

Given a mean blood lead and the fact that blood 

leads are distributed lead normal, we can calculate 

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d i s t ributio r i s u s i n g a g e o in etric standard deviation in t h i s 

case. 

The value that we are proposing to use is derived 

from a -point-source standard. It is coincidental 1y identical 

ti::i that which appeared in the criteria document from the NH2 

analysis. 

This list is for the different sub-populations. 

We got several comments on this. There was a little 

confusion which models are being used for what populations. 

For young children, we have three models we feel 

that ^^re available. We are proposing that the uptake 

biokinetic mp;>del is the one of choice. 

F'Dr adults, given the lack of data on biokinetics, 

for example during pregnancy, we feel that this model is the 

appropr i ate one to use. One of the reasons not to use the 

more detailed model for adults is that it would require large 

amounts of input data g>:iing back in history to account fp:>r 

their long-term exposure. 

As Bob mentioneed, the bulk of our talk today, 

this morning at least, will be trying to clarify the issues 

raised in the comments that we received from you. 

We are going to try to go through them quickly, 

but in enough detail that everyone understands n<;pt only our 

understanding of the comments, but our responses. 

We have comments on these issues here. We will 

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have discussion later in the day. If anyone wants to talk 

a b out on e t hi ng in p a r t icular, in detai1 1 ater, we wi11 be 

glad to put this slide back on. 

I think there is a number on each of the slides BO 

we can readily find it. 

We have several comments on the •::• r gan i zat i on and 

presentation of the report, especially on the need t'~p clarify 

the overall plan and how this exposure analysis fits in tcp 

the review of the standard. We need to discuss a little bit 

more, as well, implications for regulatory actions: What 

models are being used for what populations and why? 

Both of those comments, I think, we will try to 

address with an expanded introduction where we clarify the 

uses of the various models. We are also going to have the 

Executive Summary which I think will help the reader focus in 

on what is important. 

How will differences in blood-lead results be 

resolved? We are planning on presenting results from all of 

the models. 

Again, we are proposing that only the mid-p<:'int 

results from the uptake biokinetic model for children and the 

disaggregate model for adults be used for further analyses. 

There was a comment for us to define the bloodlead end points, which we will be more specific on: np:>t only 

the mean blood-lead, but percentage of levels above selected 

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1 blood-lead cutoffs. 

2 We wij. 1 talk about some levee Is later today as an 

3 example when we present case-study results. 

4 CHAIRMAN LARSON: If any Subcommittee members have 

5 any responses or comments, please feel free to voice them. 

6 MR. FLAAK: Yes. 

7 Now, we will briefly go through the comments 

8 classified by the sections in the report, starting with air9 lead where we had some information on non-attainment areas. 

10 That is a good idea. We are going to add some more recent 

11 air quality data to that I will show in a minute. 

12 We can talk about non-attainment problems as well, 

13 then. 

14 There are several comments on the gasoline phase15 down. We will go through these sequentially. 

16 We should discuss that the data on automotive 

17 airborne lead is used interchangeably with data from point 

18 sources. I think Granger Morgan made that comment. He is 

19 not here today. 

20 We will go back and check that we are clear on 

21 this, but all the data that we use for exposure estimates are 

22 point-source specific: for example respiratory deposition 

23 efficiencies, soil and dust level, and so forth. 

24 There are comments to illustrate the rapid decline 

25 in air lead because of the phase-down. Again, we have some 

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more recent data I will sh'Dw you. on the next slide. 

We discuss the impacts of the decline on exposure? 

estimates. Again, we will go back and check on this. We 

m::'te this in several places in the report. We will try tc.:' 

highlight that somewhere in the front. 

A comment that in estimating a future baseline 

blood-lead level, we usepd the gasc;p.line bl cDd-l ead regression 

analyses that were done a few years ago and that were 

updated, actually, in the ATSDR Report. 

We should discuss the problems of extrapolating 

those results t'i" ppi'int sources in rural areas and whether p;ir 

not it is appropr i ate to assume the same shape of the bloodlead distribution before and after the phase-down. 

We found that although there is a different 

interset to the gasoline/lead r el at i iDnshi p , the slope 

coefficient in the analysis was almost identical for both 

populat i ons. 

We are using tests to make the distribution of 

PSD-directed point sources, although it turns out to be 

identical to the analyses result. 

Here is some of the data that we are going to be 

adding to the report. You can see the trends in air quality 

over the last seven years and the dramatic declines that have 

occurred in urban areas in these roadside—oriented monitors. 

This is especially evident looking at the 

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microscale sites which ar& specifically designed to pick up 

high impact lead emissions from busy roadways. We have some 

more recent data o n na ti onwi de mon it o r i n g that works as we11. 

DR. CLARK: What is the middlethere on that 

chart? What is that the middle of? 

MR. COHEN: It is called a middle-scale site and 

it has a further setback from a somewhat less-traveled 

roadway than what the microscale monitor picks up. I am n>:>t 

sure of the exact traffic. 

The neighborhood scale site is a smaller roadway 

set back a little farther. 

We got several comments on our discussion of soil 

and dust lead and the problems in comparing different data 

from various studies; also, that differences in particle size 

may effect GI uptake If leaded dust. 

We recognize those problems. One of the things we 

try to do is confine our use of data to those studies that 

collected the upper layer of soil: in other words, that layer 

that children are most exposed to. 

There are, of course, remaining variations in soi1 

and dust levels among various locations and that is reflected 

in the uptake estimates, especially in the difference of 

blood-lead soil and dust-lead slits as talked about in the 

criteria document; but we agree that we should highlight that 

a little bit more. 

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There was a question on why was the data from 

Silver Valley, Idaho. That was a closed facility. 

Nevertheless, there are data in there that we think are 

really useful, especially the soil and dust slit responses 

CPver t i ine t o negligible air lead. 

We are going. tpD try to add S'Dme of thctt data as it 

i s avai1able. 

As far as the soi1-1 ead/blood-lead relationship 

analyses that CBC presented, we are informed that it is not 

comparable to the other data that we site. We have asked CDC 

for further re-analyses. 

There was a comment that the Milkie Study 

attributed tiiO'D much of the soil-leading in downtown Baltimore 

to automobile emissipDns given the prevalence p:>f old homes 

with lead paint trim. 

We are going to clarify that. We are going to 

incorporate that comment and, also, add some supporting data 

from Chicago. 

These next tw>D basically are suggesting that we 

add some supppDrting data from Cincinnati and Boston on soil, 

on street and house dust, and on soi1/blood-lead 

relationships: add both the Q-HY and Mike's paper. 

There was a comment that the Dutch data of Clausen 

may be unrepresentative. In fact, the results are pretty 

much consistent with the Binder, et al findings from East 

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'J.O 

Helena. 

One thing we did was only use the Dutch data, the 

control data results from the hospitalised children. We 

thought it was necessary to cPOrrect the Binder data for 

elemental abs«orptipon from the diet of those? trace elements.' 

In fact, that is something that has been 

incorporated intpo the ongoing Environmental Protection Agency 

studies in Washingt>on State and the U-Mass/Amhurst studies 

from Calabrese and Gilbert. 

We are going tpo add those data. Hopefully they 

will be available soon. 

There was a cpomment that we should reference some 

of the high-soil lead problems around facilities pother than 

smelters, various manufacturing facilities. We tried to use 

all the data that we knew about from the literature. 

If anyone has anything in their files, we would be 

glad to add it. 

We need to clarify, I think, the distinction 

between street dust and soil dust. That concept, I guess, 

appeared in the criteria document which we referred to. 

We can try to clarify that a little bit more. We 

really use that in any quantitative way. 

There were various comments on dietary lead: one, 

that the FDA estimates of lead intake are uncertain and can 

underestimate in a lot of cases. The report to Congress 

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p o i n t s o u t a 1 o t o f t h o s e p r PO b 1 e m s. 

I think we can refer back to that discussion in 

the report for that; but just to emphasize, the dietaryestimates that we use and that are in that rep port to don grass 

really represent typical baseline levels. 

They are not. intended to capture the high-level 

intakes that certainly exist. 

One of the things we hope to achieve by using the 

GSD is to capture that variability in exposure patterns. I 

think we can add some comparison between the estimates that 

we come up with through Robbs' model and the ATSDR estimates. 

They are actually very similar. 

That is interesting to point out: they are similar 

not only for years, but for specific age/sex categories. 

There was a comment that our water-lead 

projections, based on Office of Drinking Water's estimates 

from their August proposal, were a little optimistic. We 

agreed about the uncertainty in those projections resulting 

from mot only the prioposed revisions to the standard, but the 

recent solder ban. 

We are just not sure how any of that is going to 

fall out. We feel that, to be ctonservative, it is probably 

better to maintain future drinking-water levels at current 

concentrations. 

We got some revised input from ODW to support 

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St-'v. 

m'A 

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that . 

Mpost .of the data that we cite .on dietary lead were 

based ion post —1978 estimates. Mike pointed out that we 

should note the decline that occurred before 1978. 

DR. M A H A F F E Y: Is it p >o s s i b 1 e t o g e t a n y m o r e 

r ec e n t d a t a in the last f ew y e ar s? 

MR. COHEN: On water-lead? 

DR. MAHAFFEY: On diet. 

MR. COHEN: I thi nk we are using 1986. 

MR. HAINES: 1985 was the last that relates to 

that. 

MR. COHEN: 1985? 

MR. HAINES: It is just about time to get the next 

batch available. In fact, we will probably have them within 

the next three months. 

DR. MAHAFFEY: As I understand for the current 

month's data, the numbers are even 1 power. 

MR. HAINES: There has been a definite trend. 

MR. COHEN: If you know a way for us to get that, 

that would be very helpful. We will try t>o reference that 

pre-1978 data. 

In fact, that kind of data helped validate the 

total food—level criteria document. So it is a good pioint 

that we should have it. 

We should note that lipids in lactose may increase 

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lead absorption ; and we should modif y our statement abiout 

f a 51 i n g a d u 11 s . T h e i r a b s o r p t i o n r a t e :i. s p r o b a b 1 y c 1 o s e r t io 

t ki a t CP f P: ki i 1 d r p= n . 

In both of those we will make those changes. 

DR. MAHAFFEY: Another point in there is that I 

dpon't think there are many studies on fasting children sio 

that that absiorpti'On rate? could be even higher. 

MR. COHEN: Yes. 

We have several comments on how tpo improve our 

discussion in paint iead. All of them will be incorporated. 

There is a question on whether or mot there is any 

mpore recent housing data. I d-on't know of any. If anyone 

knows >of anything, again we will be happy to incorporate it. 

We are talking about the prevalence of leadpainted homes across the country. 

There was a general agreement with our approach to 

exclude from the analyses kids with high paint-lead 

exposures. That is an issue that we brought up with the full 

Committee in 1986. They endorsed that approach. 

Although in this report we probably should make it 

clear that we are under-estimating potential benefits to 

children with significant lead exposures, we did do a 

simplistic analysis in one of the appendices illustrating the 

potential impact of paint lead relative to these other 

exposures that we are talking about. We can highlight that 

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up front a little bit (more. 

We have comments pon Sectiion V, which is the 

section where we talk ab'out the aggregate/disaggregate model. 

Th i ngs gCJt a little c 1 ut tered. 

To make things really simple, we are going to 

remove the table that contains all the detailed data. We d'O 

want t'O kee?p the table after that where we summarize the 

slopes. It clearly distinguishes the disaggregate versus the 

aggregate? slopes. 

We should include data on uncertainties associated 

with the slope?. This is another comment that Granger made. 

DR. MAHAFFEY: I think there is a fundamental 

uncertainty, too, on the slopes. I think that virtually all 

the data on slopes was 'Obtained from male subjects. 

Since the population that you are very concerned 

about is pregnant women, it is important to note that this is 

unknown and missing data. 

MR. COHEN: Right. 

DR. MAHAFFEY: It is a major problem. 

MR. COHEN: Good point. Yes. 

There was a comment to compare the studies by 

Chamberlain, et al and Manton to see how their b<one-lead 

resorption adjustment compares. Allan has done some work 

recently on thatd, and we can incorporate some of those 

results. 

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B'Oth papers basically run to similar cone 1 usi oris 

by different methods: basically that a substantially fraction 

.of adult lead is due to the release of endogenous bone? lead. 

We will add more discussion >on those two papers: maybe 

anything else that anyone can identify. 

There was a quest iion abiout the biokinetic rmodel . 

Does the fact that the? model accounts f'or cumulative 

exposures mean t hat t he c ior r e 1 at i on shows a 1 i f et i me aver age? 

blood-lead? 

The cumulative aspect refers to the long-term 

storage from prior exposure. New York University 

successfully validated the model against autopsy data. Agespecific intakes that we use are designed to allow, of 

course, blood-lead estimates at any age, though. 

We think that that is one of the main advantages, 

again, of the model: that it can capture relatively shortterm changes in exposures compared to the other approaches. 

There was a question where the RYU slope was used. 

It was used in a couple of places: one to 

illustrate, for infants, the relationship between blood-lead 

and uptake. It is also used in the criteria document 

disaggregate model. 

We also refer to it again when we try to estimate 

the impact of dietary lead changes on baseline blood-lead. 

The slope of the RYU data seem to support that. 

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Again, Allan Marcus has continued his reanalysis 

pof those data including the rat data. I will try t>o add some 

io f t h a t t o t h e r e? p o r t. 

There is agreement POn our approach to focus on 

absiorbed lead data to support our absorption assumptions. 

These are relatively good compared t'O m>ost other data sets we 

have to deal with. 

We agreed that we should add more discussion on 

the importance of the various assumptiions up front. 

There was a comment on the number of hours that 

children are estimated to spend outdoors. It may be 

misleading given winter /summer differences, fpor example. 

It is true that in trying to capture year-' r pound 

exposures we are smoothing out seasonal variations. It would 

be possible to distinguish cooler-month exposures. 

We would present those blood-lead estimates on a 

seas'onal basis as peak exposure levels, for example. We 

don't anticipate that they would be different, however, from 

the upper bound estimates that we generate now. 

The end result at six years of age probably would 

not be much different. The two-year-old blood-lead certainly 

would be different because of the age-dependent. We are 

looking right now to see if the available data are sufficient 

to do some sensitivity analysis. 

If anyone has any.age-specific, seasonal-specific 

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data , i t would be reall y usefu l ion outd'O'Or behavior patterns . 

There, i s a relate d observatio n tha t th e tim e 

•outdoor s may be? indicativ e not onl y of exposure perio d alpone, 

b ut pla y habits . I t i s tru e tha t severa l parameter s i n th e 

m'0d pa 1 a.r e sur r og a t es t o summar i :: e mor e? c omp 1 e x var i ab 1 es . 

We sho u Id r e a 11 y h i g h 1 i g i -i t t h a t p >o i n t a n d s 'O m e 

m PO r e r e? c e? n t refer e n c a s t hi a t w e h a v e. 

A g a i n, s m 'O >o t h i n g o f c h i 1 d h o >o d a b s o r p t i o n r a t e s m a y 

bp?? inappropriate. The reason we did that is that we had no 

data fpor a lot of the age groups. We thought smoothing was 

the most reasonable alternative. 

The data for children >on time spent outdoors 

appears soft. We referred 'only to an informal parental 

survey. That was an error in our citations. Actually it 

comes from four different behavi>oral studies listed here?. 

We tried to confirm it by siome formal survey. 

We should alsio mote that the East Helena Kellogg 

studies fpound a number of kids who spent more than the 

.average hours outside during the summer. 

There was an observation that the predicted bloodleads had a less dispersed distribution than the "Observed 

blood-leads in the validati>on exercise at East Helena. 

Again, given the available data, we are predicting average 

exposures. 

We c>ompared those two distr i but ions only to 

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illustrate the quality >of the consistency. I don't think the 

rniodel is ever gpoing to be able, unless we have a 3 ot mor e 

data, t'.o account for all the variations in exposures and the? 

s io u r c e s t hat w e d o n ' t m e a s u r e n o w. 

An important ppoint is that the mean blO'Od-lead 

predicted was nearly identical to the 'Observed mean in East 

Helena. 

There was a comment that the GST measured in East 

Helena was similar to that found in Bunker Hill Sme?lter. 

That is a nice thing for us to add to the report. I think we 

have the appropriate data to derive that. 

MR. HAINES: I think that was in the CDC 

information. 

MR. COHEN: Yes. 

There were two comments—again, I think Granger 

made these—that are related: no indication of the expected 

accuracy of the input data; and, are we over-explaining given 

the inherent inaccuracies? 

It was difficult for us to assign a statistical 

uncertainty to the model predictions given the limited data 

that we had to work with. The sensitivity of the predictions 

can be judged by the lower and upper bounds. 

Some key-model parameters that I flashed up 

briefly before were adjusted within the range that we felt 

plausible to better fit the observed limits. 

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'Z'3 

D i d t hi e? v a 1 i d a t i o n i n c 1 u d pa R U N C'? I t h i n k , M i k e, 

you were not clear ion that. Actually, RUN C we thought was 

o u r u .11 i ni a t e t e? s t. It incl u d e d all t hi e? v a r i a b 1 e s, i n c 1 u d i n g 

air, dust and soil relationships, especially, that we have to 

estimate when we go out to dio our case studies. 

So the answer is: Yes. But we probably shiould 

make that a little more clear. 

Again, we should clarify the discussion on our use 

of mid-point estimates in relati'on to the 1 ower and upper 

b'ound estimates. We feel that the mi d-p'oi nt is a more 

plausible and more predictive statistic. 

There was the comment that the findings from East 

Helena are consistent with other similar in Dallas and Bunker 

Hill with the m'odel proved with more discrete exposure 

estimates: in other words, looking at block-by-block 

exposures as opposed to census track patterns, for example. 

I hope we can note that by referring to some of 

the results from Bunker Hill. I don't know if that is 

avai1able yet. 

We had discussion on how air quality interpolation 

procedures will be used. In East Helena, we had a more dense 

monitoring network than we usually have. So we were able t<o 

compare interpolated smooth monitoring values versus model 

data from the ISE dispersion model, which of course is what 

we are limited to when we model future scenarios. 

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It turns out that the results were fairly similar. 

When we d>o our case studies, th'ouyh, we are q>oing to u;-;e the 

ISC dispersion modeling. 

This is S'omething we talked about earlier. We 

will add more di scussi on-—hopefully we will hear (more today---

on how the approaches that we talk ab'out may be applied to 

•other lead exposure assessments. 

We are hearing a lot of interest from other 

programs, not only within the Agency but outside?, on using 

t h e s e tools f o r s o i 1 -1 e a d , for e x ample, a s s e s s m e? n t s. 

In East Helena, we looked at area one, which was 

within a mile, and area two, which was a little farther out. 

There appeared to be some.differences in the slopes that were 

derived from the model. 

The comments probably related to unmeasured 

variables: demographic or nutritional factors, for example. 

We agreed that those variables should be considered. 

One finding in East Helena was that there was no 

significant improvement in predicting blood-lead after 

including dietary habits and income, for example. That was 

attributed to the low prevalence of detectable lead paint 

there, and the relative homogeneity in housing quality and 

social status. 

That is another reason why East Helena represented 

a good validation case. I think similar results were found 

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i n Bunker Hi 11 . 

In other areas, these fact'Ors are ppotentially very 

power determinates of blood-lead; but we are? not going to 

have the data that is necessary to incorporate that. That is 

•one of the reasons why we are using the geometric standard 

d e v i a tion, for e x a m p1e, t o est ima t e the comp1ete d i st r i b ut ion 

of b1ood-leads. 

We just can't capture all the variability with the 

modeling that is available at this time. 

There is a little confusion, probably, about our 

baseline blood-lead projection in the aggregate mpodel . If 

extrapolated, that level would suggest only 20,000 kids would 

have blood-leads above 10 in 1990 versus over five times that 

now just living in inner city areas in the ATSDR Report. 

I guess we need to emphasize or be clear that the 

baseline blood-lead projects represent rural non-air exposure 

with minimal paint lead. 

DR. MUSHAK: The point of the comment I made there 

was the fact that part of it gives you some idea of how much 

of a population of children you are going to do something 

for. 

MR. COHEN: Right. 

DR. MUSHAK: What size of population you are not. 

MR. COHEN: Yes. We probably should add that. 

DR. MUSHAK: If you work through the thing as I 

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_„.._ . .: j.. .i. 

Q c<. V t? J. '-• •-• l I V i <1 i, yiou fin d tha t one-sevent h of al l th e childre n 

are? qo i ng L- o r i -?i v t: L: •J. &ad J. eve l s pr o babl y abov e 10 

m i c r o g r a m s. 

All of these low-SES inner city children, still in 

1990, I woLI 1 d i mag i n e, wou 1 d hi ave? b 1 o'Od •-1 ead s n ear 10 or 

above,, 

MR. COHEN: Yes. 

DR. MUSHAK: So the fact is that that you either 

choose to write them off complete and say, "That is HUD's 

problem" or "That is some hybrid problem of HUD," or you try 

to 1'Oiok at a separate scenario for them and say that even a 

small amount of air-lead adjustment will help them. 

MR. COHEN: Yes. The other thing that probably 

would help is, when we add the prevalence of children living 

in the vicinity of these sources,— 

DR. MUSHAK: We talked last night about the fact 

that many points sources are in urban areas which multiply 

impact these same children. 

MR. COHEN: Yes. 

DR. MUSHAK: You are only going to catch a part of 

it. 

MR. COHEN: Right. 

On Hispanic children, we would love to have that 

data. We were not able to get the summary data so far. We 

have been trying for a couple of years. 

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Joel Schwartz has be?en able to get a lot pof the 

t li i n g s o n t h at. . I d o n ' t k n o w w h y. 

DR. MUSHAK: Let me interject our experience. 

We tried to get Hispanic data for a report to 

Congress. The? super-perfectionists at National Center for 

Health Statistics were unhappy with know the data was 

avai 1 ab 1 e?. 

Plus, I believe, there was some unfortunate early 

political capital that was made of that data base earlier. 

So they are very antsy about the quality of that. 

MR. COHEN: Yes. 

DR. RABINOWITZ: So because the quality of the 

data may not be good enough, it may not be available at all? 

DR. MUSHAK: That is their version. I am getting 

information second hand. We have not seen the run. 

That has been our experience, too, in this. 

MR. COHEN: There was the comment that older 

populations may not experience the projected declines that we 

are predicting because of their high historical exposures. 

We really need to emphasize that point up front, 

although the one opportunity we have, really, to make that 

adjustment is using the bone-lead resorption adjustment from 

Chamberlain; but we will add some more discussion on that. 

DR. MUSHAK: I am not sure Chamberlain does the 

est eopor ot i c women,— 

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1 MR. COHEN: No , he? does not . 

2 DR. MUSHAK L —whic h would be a multipl e of , like , 

3 2 por 2-1 /2 . 

4 DR. MAHAFFEY : I think yo u reall y hav e to mak e 

5 that point strongly . I did n>ot go back to Chamberlai n of 

6 1983, but I really don't believe that there is that much data 

7 on the t iopi c . 

8 la m c ion c er n ed t h a t we ar e g e11 i n g th e typ e o f 

9 model validatio n in her e tha t doe s not dea l with th e fac t 

10 tha t ther e is a lo t of biological/physiolog i ca l dat a tha t are 

11 absolutel y missing . 

12 DR. MUSHAK: Chamberlain's stil l in th e 1.3 

13 factor . Didn' t tha t stil l relat e back t o th e isotopic ? In 

14 othe r words, half went t o th e bone and the n of tha t half came 

15 out : 25 percent . 

16 MR. COHEN: Yes. That was th e trace . 

17 DR. MUSHAK: So tha t i s not even good for us. 

18 That i s stil l a short-ter m bone resorptio n response . 

19 MR. COHEN: Yes . 

20 DR. MARCUS: There was some more recent work that 

21 Chamberlai n did in the 1985 paper . It wa s a synthesi s of 

22 dat a from a variet y of differen t sources : a compartmenta l 

23 kinetic-typ e model . 

24 It still cam e up with an estimat e of 20-som e 

25 percent for after some 50 years of exposure, pumping the lead 

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best 

into the bone?. 

DR. MUSHAK: Manton's data is probably t, 

for it, would you say'? 

DR. MARCUS: Manton's data is extremely suggestive 

of the importance of this from a quantitative point >of vie?w. 

Mai"it >:• ri had t o make some assumpt i ons abiout t he 

contribu t i o n s f r o m c o n c u r r e? n t e x p o s u r e s. 

DR. MUSHAK: As did any modeling used byChamber 1 ai n. 

DR. MARCUS: Well, C h amberlain had t o ma k e a 

different set of assumptions. I would say that either value? 

h as sort of be?en cast in marble; but they are both reasonably 

in concord that a substantial fraction, certainly upwards of 

20 percent in adult males who have had substantial historical 

exposure to lead, has created a bone pool or bone reservoir 

of lead that is gpoing to be coming back out, and will be 

detectable in blood-lead. 

DR. .RABINOWITZ: Another set of data that could 

bear >on this is from occupational ly-exposed people who have 

much higher blood-leads and much higher bone stores, and 

watching the very slow rate in decline of blood-lead in that 

population. 

It speaks a little bit about how available bionelead is for later blpo^od-lead elevations. I d-on't know how 

applicable it is because they may be kind of pathological 

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cases in that their bone-leads are so high. I don't know if 

y io u w a n t t o u s e t h a t t o a d d r e s s 111 e g e n e r a 1 p o p u 1 a t i o n . 

B ut i t s a y s s o m e t h i n g a b o u t rat e? s, a n y h o w. 

DR. MARCUS: Yes. They have a long-term half-life 

in blood from lead resorption in the bone of 5-pointsomething. 

MR. COHEN: We also looked at the Silver Valleystudy a little imore superficially than East Helena, but the 

control areas there did not have measured air-lead levels and 

we will note that. 

We got comments on our estimated relationships 

between air, sioi 1 and dust. It is difficult to quantify 

tempporal changes in soil and dust, especially in some sites: 

for example, highly-contaminated areas where current air-lead 

effects are neglible, in closed facilities; or clean areas 

where soil dust accumulations may be non-linear. 

Then we used all the available data from a wide 

variety of point source areas that reported quality-assure 

pr ot ocols. 

Based on the limited longitudinal data, we have 

some assurance that the relationships are, in general 

plausible. 

The uncertainties, however, regarding the temporal 

patterns of soil and dust changes are the reasons that we 

decided to use two different assumptions: one, where we keep 

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soil-lea d constan t ove r time ; an d th e othe r wher e we var y 

soil—lea d wit h air—lead . 

When we tal k ab>out th e cas e stud y results , yo u 

f er err 

thos e tw>o assump t i ons. 

T h e non-1inea r relationship s tha t we 1 coke d a t fo r 

t h e dat a set s tha t we examine d wer e no t an y beet te r tha n the? 

1 i i'"iear mo del s tha t wer e used . 

Y e? s , t hi e s o i 1 a n d dus t e q u a t i o n s d o i n c 1 u d e 

historica l deposit s o f lea d fro m pri'o r deposition . "Ar e th e 

equation s i n Appendi x B intende d t o b e use d recursively? " 

T h e answe r i s no , simply . 

Equatio n 3. 3 f'or dust-lea d i s intende d t o b e use d 

i f onl y air-lea d i s available ; and 3. 2 shoul d b e use d fo r 

dus t i f bot h air-lea d and soil-lea d ar e available ; an d we 

wil l ad d discussio n on that . 

Ther e was a questio n abou t ou r discussio n i n 7.7 : 

whethe r o r no t tha t implie s tha t th e air-qualit y standar d 

shoul d b e establishe d f>or certai n incorporate d soil - an d 

dust-lea d level s o r tha t soi l shoul d b e reduce d t o a 

particula r level . 

Tha t i s an interestin g polic y issu e tha t we migh t 

wan t t o tal k abou t later ; but , analytically , ou r inten t wa s 

t o accoun t fo r al l pathways , includin g elevate d soi l an d 

dust , tha t alread y exis t aroun d poin t sources . 

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The; relationships were derived from areas 

e x c 1 u d i n g t hi o s e ' c 1 o s e d fa c i 1 i t i e s t h a t w e t a 1 k e d a b o u t: n o 

I-I e g 1 i g i b 1 e a i r -1 •:-? ad, but h i g h 1 y - c o n t a m i n a t e d s o i 1 a n d d u s t . 

Similarly , th e air/blood-1ea d slope s that w e had 

fr'Om childre n ar e derive d from operatin g poin t sources . 

Ther e wa s a q u e s t i o n i n a :i. r -lea d m o n i t o r i n g : 

w hi e 11 "i e r o r n o t w e p 1 a n o n r e? a r r a n g i n g '.j u r m o nit o r i n g n e t w o r k 

a w a y from m o bil e source s and f o c u s >o n s t a t i o n ary s o u r c e s. 

The answer to that is: Yes. 

That is something that we will discuss when we 

actually propose the standard; but clearly the?re is a nee?d to 

d'O that. 

There was a discussion on the height of monitors 

as it relates to the breathing height of children. It is 

important that we should note this in the report: that any of 

the data are from roof-top, real-world monitors. It is not 

available to get personalized monitoring for children. 

We can add further references from the criteria 

document on the vertical gradients, but most of that data is 

from mobile-source situations. 

That is about it for our summary on the comments. 

The next step for us is to finalize the exposure report by 

incorporating the comments. 

That will, in turn, become a source for the staff 

paper case-study analyses that we will get into in early 

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1939; and alsio will become? a reference for the regulatory 

impact analysis, as well as other regulatiory analyses both 

inside? and outside the Environmental Protection Agency. 

Hopefully, we will have time? to discuss those 

other analyses at the? end of the day. 

Thank you for bearing with us here. 

CHAIRMAN LARSON: Thank you, Jeff. 

We have not had a lot of back and forth 

discussion. So we seem to be breezing right along here. 

Perhaps we can take the time at this point to ask 

for general discussion. 

MR. FLAAK: We are running a little ahead of 

schedule. 

CHAIRMAN LARSON: Let's have the public comments 

now. Gale, are you prepared? 

MR. HOFFNAGLE: It is a little early, but we can 

talk about our comments. 

CHAIRMAN LARSON: All right. Would you, please? 

E'yislic. Q28.-DS2Hl.Sl Q&1.-2 hJ2.£.£0£3l£.i. TRC Environmental. 

£

:20.§ul_.tants 

MR. HOFFNAGLE: I am Gale Hoffnagle from TRC 

Environmental Consultants. I represent the Lead Industries 

Association. 

We have prepared a set of comments about the 

exp'osure assessment methodology. We have been working with 

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Jeff Ciohen and John Haines since the? last CASAC meeting. 

We reviewed the staff paper and provided what data 

we c o u 1 d , a n ci a n a 1 y s is that we c o u Id t o be he 1 p f u 1 t o t I-i eproce?ss. 

We have taken a lcok at this document. I am sorry 

I did not use the invit.ation to get comments in by September 

9, but we are a little behind the eight ball here. 

I n r e? c o g n i t i o n o f y o ur d e? s i r e t o h a v e? t h e? p u b lie 

comments be different than what is in the written text, I 

think there? are really only two major differences we have? 

with the exposure assessment methodology at this point. I 

would like to highlight those. 

We agree generally with the assessment 

methodology. We feel that it goes a long way toward 

overcoming some of the objections that we had before, and 

that it includes a lot better set of data and more realistic 

conclusions directed at sources rather than a lot more 

generalized problem. 

We also agree with Jeff's statement, and the 

conclusion here basically, that the uptake biokinetic model 

is the right way at this point to go after the problem: that 

it offers some real advantages in terms of dividing out among 

the source categories where the problems lies; that is it not 

available in the aggregate or the disaggregate model. 

Our concern has been primarily in two areas: those 

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are? in the act u a 1 r e 1 a t i >o n s i-1 i p b e t w e? e n a i r -1 e a d, and soiland dust-lead that has been generated here. 

I am concerne?d about it from the point >of view >of 

the selection afterwards, after the fact, of the data that is 

in Table A-3, the Appendix table which lists all kinds of 

sets of data, rather than going ahead and using the East 

H"31 en a r esu Its. 

I think you developed a relationship at East 

Helena that is correct and it is accurate. It uses a larger 

data set to develop that relationship. 

So we would propose that you do that. 

I have prepared to plots here that, I think, help 

us focus—you have copies of them—on the issue. I have 

taken the Table A-3 data, which represent all the sets of 

data that could be looked at, and looked at individual points 

on the Table A-3 data. 

I have taken out of that the ones that were agreed 

to in the paper, and we had agreed that those should be taken 

out; but I have also taken out the ones that are not pointsource related. So all we have left is the point-sourcerelated ones. 

I took out the ones from Bartlett, the five small 

copper-smelter type facilities. All of those air-lead 

concentrations are low so I don't think they add much to the 

slope. 

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B ut in their pap er, t hey cou1d not f ind any 

v el at i ponshi p between the air- and soil—leads at al 1 , If they 

cannot find it in the paper itself, it is hard to use it in 

an extrapolation like this. 

Here is our air-lead/soi1-1ead versus air1 '••?ad/'soi 1 — 1 eacj ccncentrati on basically in thousands '0f 

micrograms per gram ppm versus ambient air concentrations. 

We have a range? from 2 to 4. I don't think that 

we should concern 'ourselves with the concentrations that are 

greater than 4, let's say. So I removed the ones that are 

high; and, also, the S'oil-lead concentrations that are real 

h i g h . 

I thin k thes e represen t differen t kind s of 

c i r c ums t ane es . 

Thes e are th e differen t dat a set s f>or poin t 

sources. What is interesting about them is the Toronto data 

and the Brussels data. This is an Omaha data point, this is 

another Toronto data point, but all the ones that are up here 

on top represent urban point-source situations: Toronto and 

Brussels. 

The ones that are on the bottom represent rurals, 

in essence. This line is the line of blood-1ead/soi1-lead of 

15 times 579 air-lead that was used in Table 4-1 and used, 

finally, in the analysis; and this line is the line from East 

Helena. 

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If I understand it correctly, Jeff, the line from 

East Helena includes a lot mores data points than the data 

points that were on Table A-3. There? are some East Helena 

c j a t a p o i n t s her e— t ki i s o n e, t h i s o n e, this o n e, 111 i s o n e, a n d 

thi s p.one?—but those a.re different data poi nts than the one 

you used to deve 1 op this line or thi s s 1 "0pe. 

MR. COHEN: That is right. 

The summary data that we used from the literature?, 

though, is home-specific. So, in fact, they do include more 

homes than is reflected. The individual data points from the 

different studies represent a large number of homes. 

MR. HOFFNAGLE: A large number of average sets; of 

homes, right? 

MR. COHEN: Yes. 

MR. HOFFNAGLE: My point is that the slope of this 

line from East Helena is derived differently than just the?se 

five p'oints. So if you tried to draw a line through the East 

Helena points up here, you would not get this one. 

We have a tendency to believe that most of the 

situations that we ought to be talking about, rural-area 

situations where we don't have automotive-lead input or 

paint-lead input and so forth, ought to consider this East 

Helena line: that it is better for them. 

I also dotted in the range of values that is used 

ono Table A-4 by plotting them in. What I don't know, and 

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what I would like? to ask, is: H'ow we?re the? range of values 

set for soil and f>or household dust? 

On Table 4-1 you have a range, but I don't 

under st and f r om t he d'0c ument how t he range was deve 1 oped . 

MR. COHEN: In Table A-4. 

MR. HOFFNAGLE: Table 4-1 has a range. Appendix A 

gives us a me?an value and a sliope, but I don't know how the 

range was developed. 

Table A-4 has a range of soil dust and household 

dust. 

MR. COHEN: Not Table 4. 

MR. HOFFNAGLE: 4-1. 

CPause3 

MR. COHEN: Line 12? 

MR. HOFFNAGLE: Yes. Lines 12 and 13. I don't 

know how those ranges were developed. 

In the staff paper, we knew because it came from a 

table in the Appendix, how the ranges were developed. 

DR. MARCUS: I will have to go back and verify 

this, but I think these ranges represent the 95 percent 

confidence intervals that were derived from that. 

MR. HOFFNAGLE: Okay. That's fine. 

In order to reproduce it for this slope, which you 

have not done, I would like to reproduce the range for the 

East Helena slope. I did not have the methodology, but it is 

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95 percent confidence so I will have? to have? the data, too. 

It is' important because the range? of values that 

result on Table A-4--1 are a substantially larger total range, 

although somewhat shifted down, from those in the OAQPS staff 

p a p e? r f r o m t w o y e? a r s a g o. T h e r a n g e? s a r e? 1 a r g e? r . 

Fior instance,, at 1.5 micrograms per cubic meter, 

the? highest value? that appears on the table is substantially 

larger than the highest value that appeared in the original 

OAQPS staff paper. 

So if one is to look at the^top of the range and 

made one's decisions on the top of the range, it gives you a 

lot higher number .than if you are just I'O'oking at the mean. 

I would suggest—and I think the suggestion was made before — 

that you put the mean value in this table so people can look 

at it, and then the ranges and standard deviatiions. 

MR. COHEN: Yes, we should make that a little more 

c1 ear. 

Again, the equations in A-4 are the ones that we 

intend to use with the case study. 

MR. HOFFNAGLE: From the East Helena data? 

MR. COHEN: We are proposing to use what we call 

the SPTA, just the point-source data and include, as you did, 

all the urban-specific data. 

MR. HOFFNAGLE: I guess my point will be come more 

clear when you look at the second figure, which is the 

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data— w h i c h y o u ' s f :.• e n t a 1 o t >o f tim e devel o p i n g a n d 

generat i ng — :1s a bette r dat a set t o use. 

Thi s i s household dus t versus air-lead . Here i s 

t h e 'One you picked . Here? i s E a s t H e 1 e? n a o n e w h i c h , 

again , was derive d from- a differen t <:.:.& T. O f d a t a, '0 r i n 

different method'ol ogy, than the points that are on this 

curve on this 1ine. 

As you can see, it goes substantially over at 

least the data sets that I picked from.Tab1e A for you to 

look at; and the mean and range is substantially higher than 

the bulk of values that I have considered for using the data. 

This data point from El Paso, which is hardly the 

most accurate data set that we know about and, I think, is 

doubtful, I think weights this distribution if that is what 

has happened; and I am not sure that that is what happe?ne?d. 

MR. COHEN: We tried to throw out this outline. 

We tried to discuss it in the paper, I thought we did. We? 

will go back and take a look at that. 

MR. HOFFNAGLE: Okay. Please take a look at this. 

I think, looking at it this way, I am concerned 

about it. What concerns me, of course, is that these 

household dust-lead numbers do drive the final answer. In 

other words, the household dust, because the children are 

inside more than they are outside, does tend to drive that 

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fina l answer quit e = : i!-, c: t-arHall v itiau y 

MR. HAINES: If I follow your argument, are we 

focusing in on a rural situation? Keep in mind, we have? to 

be concerned not 'Only with primary smelters located in rural 

settings such as in East Helena, but we also have to worry 

about stationary sources, secondary smelters oriented in 

ur ban areas. 

I am not quite sure in my own mind that we can 

exclude p'Oi nt-source urban data from the analysis as you are 

suggesting here and focus only on East Helena because I am 

not sure that East Helena is representative of these other 

setti ngs. 

MR. HOFFNAGLE:. I agree with that; but if you are 

going to do a separate model for the urban area, then you 

need to include the other sources of lead in that urban area. 

You need to be.much more specific about it. 

MR. HAINES: Are you suggesting, then, Gale, that 

for a rura1-oriented source, we use East Helena for case 

studies, then use the total data set or segregate out the 

rural and only use urban point-source data or more urban 

locations? 

MR. HOFFNAGLE: I am saying that they are very 

different data sets and it might be more useful to look at an 

urban data set that was more convincing. 

I like to look at a case study like you have done 

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at East Helena and go through it and understand it 

completely. Rather than using the STRA data set, if you 

tiook , f or instance, the Tor onto data set, whi ch I th.i ni: :i. s 

pretty good, and looked at Torontio spec i f i c al 1 y—yo u 

developeci an urban model for Torionto as compared t>o the rural 

model for East Helena—I think that would give us more 

i n f o r m a t i o n than the S T P A data s e? t . 

MR. COHEN: Actually, Gale, one thing that 

probably was not clear when we did derive the? air /soi 1 /dust 

relationships in Appendix C, we excluded those data that were 

not collected around p>oint sources in urban area. 

I think the data sets that we 1'ooked at were 

pretty similar to the ones we have here. You excluded the 

Bartesville, Oklahoma: that suite of data. 

" MR. HOFFNAGLE: Right, but all of that data is 

right down in here, along this line. 

MR. COHEN: Right. 

MR. HOFFNAGLE: I think it was clear in the 

document that you threw out five sets of data. I went back 

through my Table A-3 and put an "X" next to the ones that you 

said you threw out. 

Did you eliminate other data sets from that table 

before you did the progressions? 

MR. COHEN: Yes. 

MR. HOFFNAGLE: We need to know that. 

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MR. COHEN: Those data were the ones that were 

just urban data. I thought we talked about all of them in 

our discussion after Table A-3, but I don't think we got all 

of them, like the Janson table, for example, which was 

c o 1 1'??c t ed i n Ch i c ag o. 

MR. HOFFNAGLE: Okay. 

MR. COHEN: So all these were the p'Oi nl-sour cespacific data. We did group primary lead smelters with 

secondary lead smelters and battery plants. 

MR. HOFFNAGLE: Okay. 

DR. RABINOWITZ: Could I ask a question? 

MR. COHEN: Sure. 

DR. RABINOWITZ: I am not even sure to ask this 

of, but in trying to get this relationship between soil-lead 

and air-lead, I have a bit of trouble understanding it 

because I imagine air-lead goes up and down, maybe hourly or 

daily 'or seasonally, where soil-leads, I imagine, just 

accumulate with time from fall-out and such. 

So I am kind of doubtful of the exercise of 

relating the two just because of the mechanism, I imagine. 

I am wondering: Has anyone tried relating soillead and air-lead where you look at the integrate air-lead in 

some way? Say, "Okay. We have had this air-lead for ten 

decades. We have had this air-lead for two years." 

Maybe this might explain why things are not all on 

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a perfec t straigh t line? . 

MR, HOFFNAGLEJ 

for a yea r and a hal f or 

f i n d a n a p p r o p r i at e d a t a 

- ••-..- i : ai i u .i. i:..i'...i.., r i i n •'t.:II i .1. '..•'.. ' i :

. J. I I M 

wel l a s other s 

' l.- '..- O O •:. I tha t wit h 

I thin k we al l under?;!; and — and I l i stc-?d i n my 

comments there—th e complexitie s tha t av e involved . In fact , 

I am ver y concerne d abou t thi s compl e?xi ty , especiall y th e 

tempo r a1 c hanges. 

We k now i n t! ie t emp ora l p r oc: e-?ss th e dep •::• s i t i >on 

occur s ove r a lon g perio d of tim e i n the? soil : i t build s up . 

Wh at , e x ac 11 y , air e t h ose ? 

What i s d'one her e i s t o tr y t o giv e u s a quic k 

metho d o 1 o g y , a simplif i e? d m e t hi o d o I o g y w i t h o u t th e t i m e? 

dependenc y t o make a relationship . I t i s ver y empirical . 

That is what has happened. We have done the best 

we can. 

I think there are lots of complexities to it. 

There are lots of reasons why we may be creating a problem, 

why we may be i nappr'Opr i atel y effective at one location or 

another because of the empiricism that we are developing 

here. 

I think generally we would like to have more data. 

I believe more data is coming. 

We are still trying to obtain the data from Fort 

Peary in Australia where they have done a large study over a 

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long period of time? and we may be able to get some more 

i n f or iii at:. on . 

But to say this is an instantaneous relationship 

is wrong. It is a l>ot more complex. 

DR. MARCUS: I would like to add a few comments on 

this rel at i'onship. 

It is complex. Some of the information we would 

have liked to have provided was left out, otherwise we would 

have had a document four times longer than it is now. 

There was some discussion there, a search for an 

underlying theory, in which we pointed out that the 

relationship between air-lead concentrations and surface-soil 

and dust concentrations depends also on the amount of nonleaded particulate in the air; and even if you had exactly 

the same c on c en t r at i on o f leaded parti cu1 at es in the air in 

one location, but the amount of non-leaded particulates that 

was falling out was larger in one location than another one, 

you would have a lower surface-soil concentration. 

I don't suggest adding unleaded dirt to the air so 

as to dilute the soil-lead concentration; but that is one of 

the concerns. 

So a completely general universal relationship is 

"Obviously not one we are looking for. 

For technical reasons, the East Helena slope may 

be eventually less relevant because of what could be called a 

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m ea sur e? me? rtt er r cv or er r or s- i n-var i ab 1 es proble m i n fittin g 

regressio n (iiode-ls: tha t is , th e air-lea d measurement for eac h 

h'ousehoi cj or for each bloc k tha t was t i eci t o a soil — or dus t — 

lead measurement i n Eas t Helena at a particula r location . 

Even though the; net wor k o f moni t o r s i n Eas t Helena 

w a s rn io r e d e n s e t h a n i r > any o the r 1 o c a t i >o n—w hi i c h i s o n e CJ f 

the? reasons we selecte d thi s for a validatio n study—th e air -

lead measur e merit s coul d hardl y be sai d t>o be s>o dens e as t o 

provid e a very complete imputatio n pof an ai r —lead for each 

block i n East Helena. There just were not that many 

rnonitors. 

I n fittin g those relationships , I have a concern 

that th e air-lea d variable , th e inpu t or predicto r or 

regresso r variabl e i n those relationships , had a considerabl e 

amount of uncer t a i rity i n it . 

I t i s known that th e technica l effec t of an 

uncertaint y and imputatio n i s t o attenuat e or flatte n th e 

regressio n slopes. 

Ther e ar e about a thousand article s on thi s 

regressio n attenuatio n effect . I t has also , I believe , been 

discusse d by Brumkreath and hi s author s i n th e American 

JJ2J=!£0.§I 2l Epidemiolog y i n 19S7. 

We believe , for th e East Helen a dat a set , i t i s 

probabl y a not-trivia l facto r i n reducin g th e estimate d 

si ope. 

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data p'Oi nts are including, of course, a range of lo::r 

It is the usual concern about having one or two air-lead 

ni o n i t C" r s repress n t i n g a reg i io n o r m etr io p o 1 i t a n a r e a „ 

What you have on the other side of that is an 

aggregate measure of soil or dust congregation, which is an 

average. In terms >of the amount of pr opor t i onat e amount of 

uncertainty in those numbers, taking i nto account the fact 

that there are a lot of reasons why the?re should be 

differences in those ratios from one location to another we? 

believe that those probably provide? a more valid relationship 

with thee uncertainties there primarily representing 

differences from one urban or rural location to another urban 

•or rural 1 IOCation. 

The analyses really are doing somewhat different 

things. The SPTA analysis, we believe, is more generalizable 

to more different kinds of conditions. 

MR. HOFFNAGLE: I have two comments. 

I disagree with that because I think East Helena 

is the best data set to use and it works better than anything 

else. 

The result is that your slope, wiht 50 parts per 

million as the constand and 579 multiplied by the ambient air 

quality, means that at 1.5 micrograms per cubic meter you are 

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lead c io ne e n t r a t i o n is d e p er.dent u p o n i m m e ci i a t e ci e p o s i t:!. o n . 

From that point of view, the sl'Ope that you have 

chosen says that the soil—le? ad concentration is deter mi ned 

directly by the air-lead concentration with only 50 parts peermillion being soil that was the?re?. 

To me, that is the far most conservative way that 

you could go in that calculation. I guess it could be 1,000 

parts per million micrograms per cubic meter, but with a 

constant of only 50 ppm that says most g no unci is 50 ppm and 

e v e r y t h i n g else c o m e s f r >o m the air, i s d e p o s i t e? d f r o rn a m b i e n t 

air. 

The second part of it is that as we move toward 

controls of smelters and all sorts of lead point sources we 

are changing the particle size distribution of those 

emissions radically. 

Any relationship we develop now, I think, changes 

the particle size distribution for a number of reasons: 

because the deposition footprint changes, where it is 

deposited changes, as well as the particle size distributions 

that are important. 

DR. MARCUS: The locations that were in the STPA 

were locations that had had fairly long histories of 

deposition at concentrations—I guess you would have to say 

historical integrated concentrations—that were not orders of 

magnitude different over the period of time that was felt to 

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be relevan t t o the ?.oi l arid lead der 

would happen :i f the': c? wer e an abrupt char 

,L 11 on , 

r; q CJ u e.- s t :l o n s a b o u t w h a t 

•; n ai r 

a n d d u s t c onc ent r at i on wo u 1 ci b e ac h i eve d . 

W e hav e all been lo poking for dat a that migh t giv e 

u s an insigh t int o this . Ther e iTiay b e analyse s forthcomin g 

f r io rn t h e l< e 13. o g g , I ci a hi o a r ea i n w h :i. ch a sm e 11 •:? r t h er e ha s 

closed down to study the changes in these concentrations over 

time? a s a resul t of an abrup t chang e in an air-lea d 

c o n c e? n t r a t i o n . 

I am not aware-? of other data sets that are as 

useful in answering that question about the effects of these 

changes. Maybe you couId answer that. 

C H AIR M A N L A R S 0 N: W e w i 1 1 m o v e? ahead. The n 

perhaps, after the break, we can have a more wide-ranging 

di scussion. 

MR. HOFFNAGLE: The other point is that we fail to 

see why you don't use the Clausen, et al number for dietary 

intake update: dirt, congestion and the like. It is 56 

milligrams per day. 

The second document that you have there is use of 

the uptake by the kinetic model at four different smelter 

sites where we have some data. It is the bound document. 

That document used the available data with the 

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update bi oki net i c mode?! to try to develop to see what the? 

relationship was around smelters •'or four smelters and we did 

Toronto twice, be?f ore anci after the quote/unquote >::• lean up , 

Thee miost useful tiling we got out of that is that 

be back—calculated a number that is very close to Clausen. 

Whet iter or niot you believe in bac k~cal cul at i on, it seems that 

5 5, GO milligrams per day represents siomething in the real 

world around these smelters as much as it did in Clausen's 

study, which has beeen discussed in other ways. 

I don't think using Binder, et al >or subtracting 

Clausen from Esinder, et al is the right way to go. We would 

urge that you go ahead and use the Clausen as the ingestion 

rate supported by our study here. 

For both the leaded-soil issue and for this, the 

Lead and Soils Conference that was hc-?ld back in May, we 

understand, is to be published in December. So we will have 

that data available in the journals at that time. 

CHAIRMAN LARSON: Thank you, Gale. 

Any questions? 

MR. COHEN: Yes. I just want to let Gale know 

that we made siome changes to the uptake estimates since he 

did that earlier analysis a year or S"0 ago. 

MR. HOFFNAGLE: Yes. Changes that are in your 

document here? 

MR. COHEN: Yes. 

EXECUTIVE COURT REPORTERS (301) 565-0064 
1 MR. HOFFNAGLE: Did I understand that you too!:: the? 

2 Eiinder, et al arid subtracted Clausen, et a.l from it to conie 

3 up with so.Tie?thing like 100 milligrams per day and a range? 

4 MR. CO KEN. Right,. I am talking about other 

5 parameters, though, as well that you might want to make those 

6 adjustments to based on this report and see if it still 

7 compares wevl 1 . 

8 The other thing is that you don't have the 

9 b i iok i ne?tic mode? 1 i t se 1 f , ot her than, I guess, t he? 

10 relationship between daily lead uptake, assuming constant 

11 uptake, and correlated with blood-lead. 

12 I think you might get a different result if you 

13 plug in different daily intakes as the kid ages and allow the? 

14 dynamics of lead movement through the body be accounted for 

15 as the mode?l does. 

16 You may get a different result. 

17 We did look at alternative soil ingestion rates, 

18 including going down to that range, in East Helena. We found 

19 that the numbers that we have actually arrived at here 

20 predict better. 

21 We under-predicted blood-lead in East Helena using 

22 that. 

23 MR. HOFFNAGLE: The uptake biokinetic model has a 

24 lot of variables in it. Which one you play with to have it 

25 match the blood-lead is a Hobson's Choice most of the time. 

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What that c o m e? s f r o rr, i s th e ci r :i. v:! r i g f o rce i r. , 

mC'del , chough. That is thee one? that drives the total up 

number. 

'I would just like to add, I went back thr .•vjh 

in the results is a table that shows you 

have: using the East Helena air-lead 

number; and the 5G milligrams per day inge?st:i. on number. 

These are the numbers that that update comes to, 

and they are very different. These are close to the mean 

values:. They are much smaller. 

I didn't know the methodology to geet the ranges 

that we talked aboutm before, and we can do that. But we 

would opt that that is a better way to approach the? 

si tuation. 

I also wanted to say, on ingestion rates, that the 

Office of Toxic Substances is looking at ingestion rates aswell. I would just make sure that you are aware of that. I 

sent them a copy of our report on ingestion rates. 

CHAIRMAN LARSON: Okay, Gale. Thank you for that. 

Do you have any further questions? 

DR. RABINOWITZ: Maybe I should say this now in 

case I forget it later. 

About using smeltered data to establish the 

regression line between air-lead and soil-lead, I just want 

to get a sense from people. 

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Is there a problem using that type of data? In 

practice, smelters don't always work nice and smoothly. 

Sometimes you have a fire in a bag house and sometimes things 

happe-n and you suddenly get a whole bunch of lead coming out 

that may not show up? in the? air data, but it doe?; show up in 

t he? soi 1 dat a. 

I w io n der i f tha t i. s n o t a n o t hi e r c o m p 1 i. c a t i n g 

factor. I dion't know if that is a real problem or not. Forme , it is an i mag i nary p r ob1 em. 

If all of these problems are? real enough, if you 

just throw out the idea of regressing soil-lead and air-lead, 

say you are not going to do it, can you still establish a 

standard? Can you still write an air-lead standard without 

correlating air-lead and soil-lead? 

Is there still some other approach to getting at 

what we are trying to do? 

MR. HOFFNAGLE: My answer to that is that 90 

percent of the changing in blood-lead that is being projected 

here is a change in soil-lead concentrations so that my 

answer is no. You cannot set it unless you have some 

understanding of what that is. 

I will resppond that, yes, sometimes you blow a bag 

house and there are accidents, et cetera, that change the 

soil-lead concentration around the facility by a lot. 

I think to go back and put it a different way is: 

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onship , ??:.. -cher je t t 

n o r C a I'I CJ 

•> tr.' :... ::A Ill : 

:Jte ' :. V.' c.:.' I" i o n -

••+: !-, 1 S 

we? hav e tha t kin d of 

e 1 a t i o n s h :i p b e; t w e? e fi th e t w o . 

fin d a relationshi p betwee n ai r lead s 

a n d d e p >o s i t e ci le a d now can we assume ths a t we wi11 b e abl e t 

f i nd a rela t i ons!'ii. p betwee n tha t ai"id the? 1-leac i 

c ortc entra t i. on':•' 

You nee d rmore data . 

CHAIRMAN LARSON: I don' t want t o sto p th e flow of 

scientifi c thought , bu t I thin k wit h thi s food fo r additiona l 

discussio n prio r t.o lunc h why don' t we tak e a 15-minut e brea k 

and fur the?r tha t discussion . 

Thank you , Gale . 

MR. HOFFNAGLE: Thank you. 

[A brief recess was taken.1 

CHAIRMAN LARSON: I think we will pick up where we 

left poff on the particular topic of the soil/air 

relationships. Ian had some comments he would like to share 

with us at this time. 

DR. von LINDERN: I had basically two comments on 

the East Helena information that was presented, one just to 

echo Mike Rabinowitz' comment the soil levels are almost 

assuredly related to the history of the facility and not to 

the current measurements that we see. 

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If you would q'O back and look either at control 

eaqui p merit err at historical monitoring data in the vicinity of 

these smelters, there have been much, much higher 

concentrations in the past, the bul!-: of it prior to 1975 arid 

it continue?s along at a lower pattern until about 1978 to 

1980 until controls came in in response to the NAAQS. 

So it is a historical problem in relating it to 

current concentrations which is a special difficulty. 

As I understand how that soil information was 

collection, with the East Helena data I believed they used 

the same methodology we used in Bunker Hill. That 

concentration is the top inch of mineral soil. 

In most cases, that is at least an inch deep in 

the S'oi 1 profile. What we call the litter layer or the 

vegetative layer of the sod is on top of that and we sample? 

that separately. I believe East Helena did as well. 

What is measured there has a temporal factor with 

it, as well. It is material that is at least a couple of 

seasons old if not older, and the most recent material is 

probably related to the current air concentrations that are 

used and would be, more appropriately, in the litter layer. 

That was my comment about explaining soils dust 

versus soils street dust situations. In at least most of the 

smelter studies, that soil value is not a surface soil 

sample: is the top inch of the minerals. 

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DR. MAHAFFEY: I hav e 

com merit s and on? 

::• 0111t~ :J I.J I" Lwant t o 

:• ci f broa d Qenar a 1 

• >oceec wi ' thos e 

I... i~l i-i .1 I''., i I .-i I '•! I... fi I •:. o I J I ••!: 3. , pi-' r It a p s a n y c o n 11 n u i n g 

v..i .L :::>'... KJ :'; si on on this particular point that was raised? 

[No response.1 

MR. COHEN: There is one other issue that Mike's 

question brings up. What do we assume for the future? 

In the paper, we identify two ail ter native 

scenarios: one? where we assume that soi 1-1 eaci responds to 

changes in air-lead, i nstantaneousl y; and then the other 

where we maintain soil-lead over time. 

We feel that over the next few years, no matter 

what we do with the air-lead situation, the soil-lead is not 

going to respond substantially. We think a more plausible 

scenario is maintaining soil-lead at whatever baseline levels 

we can define based on these empirical observations. 

When we talk about the case studies a little 

later, I think it will be a little more clear; but we are 

keeping soil-lead in the proposed approach at constant levels 

over the next few years. 

It may be much different to go out 20 years from 

now, but I think that is beyond our scope. 

DR. RABINOWITZ: So you don't use the derived 

regressi'on line between soil-lead and air-lead in your 

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ri o thin g t c p u t :L n 

11 ..^ J_ i.. .-

f ior ec as t i ng . 

MR. COHEN: Not in tht 

proposing as more plausible?. We do use it to establish a 

baseline cone ent r at i or- of soil-lead. Other wi se, we; will have 

o r s o i 1 — 1 e a d c o n c e n t r a t i o n s , 

We t n i n k thait these av s reasonable rel ct i onsh:'. ps 

for the equilibrated concentrations. 

MR. HAINES; What we think we are capturing in 

that, since we are using studies for the related ai r---qual i ty 

so i 1 -1 ead level, r ec og n i 2 i n g p r i or y ear s t o on e? t hi a t s t uci y 

collected the air-qual ity data, that there may have be can 

higher things. 

But that is representative of what is accumulated 

up to that pioint and tagged for a given study area. 

Sio it i s an air-quality marker associated with 

that and we have varying soil-lead levels with varying airquality levels. 

CHAIRMAN LARSON: Do you see any air-lead 

reasonably constant, historically, at those sites? 

MR. COHEN: Yes. We tried to use studies that did 

not have major tumultuous smelter conditions. ' You can't be? 

sure of that in any way. 

We did exclude the bag house fires and things like 

that. 

DR. MARCUS: In fact, at the East Helena site for 

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1 p.o c at i ons thc-?re was essential ly f i ve, six 

years of continuous data that made it very clear that 

c oncii t i ons had be? en reasonably constant over the length of 

time that the lead uptake histories of the children being 

simulated were up to five, six years old. 

So that was a particular 1 pocation at which we 

definitely had reason t>o believe that we were doing an 

essentially stable or constant environment. 

MR. HAINES: I have one? ot he?r obse?r vat i on on a 

concern expressed by Mike. 

You have fluctuating emissions around a smelter. 

It is a process source. A secondary smelter is the same? 

t h i n g. 

Quarterly being l-in-6-day data is not the 

greatest, but the mean value tends to reflect, to a degree?, 

peaks. You can see day-to-day variation where you have 

higher peaks, but the mean will move up in relation to those 

peaks. 

So the quarterly average is not devoid of some 

representation of that. It may not capture the true 

magnitude of them, but it is reflected in the-mean value. 

So I think, using this historical air-quality data 

gives us a reasonable basis to assume a baseline going-in 

point. 

CHAIRMAN LARSON: What do you do about historical 

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..i ,.J ... .(.. .... . .!_ ........ 

•Ute presen 

'alues i n 

do? c '! :' r; :l. n q lead i n u r b a n area s 

. i.... "rC'fii 'Ovh'?.-;r sour ces :• 

A re t h posse changes ref 1.t?c t e::-db' 

MR. COHEN:; We ar e not going t o make any changes 

:• a resul t of tha t decline . The areas we ar e \, I_I -:• i..i 1 J 1 l-.v •:::'. U 

e? c 11 y a d j a c e n t t o t! 'i e p i.o i r i t s >o u rce ; a r i i lociiunq at ar e • 

t h e soil--lea d ther e is ; do mi nated by th e emission s fro m tha t 

facii i ty . 

The gasoline contributions seem to be relatively 

small. We think we are capturing it by using the? empirical 

data, but we are not going to make any adjustment for the 

dec 1i nes. 

DR. McLAME': Well, to some extent we have. What 

we do in our forecasting methodology is we use the IFC shortterm dispersion model to figure out the points of interest 

where? people are generally located, what the ambient 

concentration is from the source, and then we add on assumed 

background. 

To some extent, if that background reflects 

whatever residual lead is in gasoline, then it will be 

captures to that extent. 

DR. MAHAFFEY: I have another question about what 

the ambient measurements are. 

In some of the oc c up at i on a1 literature, the 

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problems of Ontario in revising their acceptable occap::-

standards analysed data where there was both ambient air 

sam p 1 i i "t g p I u s the ci u s t that a c c u m u late d i n v a r i o u s p I a n t; 

T In e y reall y c a m e t o th e c o i "i c 1 u s i o n -•. nt?y 

really could not rely on just ambient sampling to reflect 

blood-lead even in occupat i ponal exposures. 

So in the kind of ambient sample you would have 

o u t s i. d e a p 1 a n t, w o u 1 d y o LA b e m i s s i n g m u c h o f t! 'i e hi e a v i e r 

particulat e tha t migh t neve r reall y sho w u p in you r ambic-?nt 

s a m plin g e v e n wit h r e1 at ive1 y high-vo1 u m e samp 1 e r s ? 

I guess I question the extent to which the ambient 

sampling—which has certainly, in time, been a relatively 

short sample—reflects what may be coming out of the plant, 

CHAIRMAN LARSON: Theare must be some relationship 

here. 

From our discussion, I am picking up an 

interpretation that these are relatively steady air levels 

over time and reflect the soil values that, thearefore, 

reflect some longer-term exposure. 

There are sort of steady-state points, if you 

will, on a graph. There is not necessarily some immediate 

relationship. 

DR. von LINDERN: I think, again, it depends on 

where you look in the soil column to some extent. When we 

look at that top inch of mineral soil, which is again below 

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Ove r tha t 15-yea r period , we have.; ha d a 10 0 fol d 

decreas e i n ai r born'?? level?? . So tha t particula r laye r stay s 

fairl y constant , i f ypou wan t t o assum e a constan t fo r that . 

Wha t i s i miiieci i a t e l y o n the? surface , though , i s 

more? of a dus t problem . 

MR. HAINES : One o f th e issue s tha t we don' t hav e 

an answe r to , whic h I thin k i s par t o f thi s problem , is : 

l-J hi a t hi i s t h e a c c e s s i b 1 e soi l 1 e v e 1 ? 

DR. vo n LINDERN : T o child r e?n . 

MR. HAINES: To children. 

I think, unfortunately, we don't have a good 

answer. We d'on't know how to characterise that: whether or 

not they are getting the top 1 to 5 centimeters. That, I 

think, is going to vary with the situation in which they are 

placed. 

If they are .on a dirt play yard in an urban area 

and they are chewing up, you have to be concerned with much 

deeper sioi 1 depths. Other situations may not be very 

accessible for a very long period of time. 

In grassy areas, it works its way down. If you 

cut off emissions, they may not have ready access to it; but 

this is something nobody has looked at that I am aware of. 

We don't know how to address it. 

This is one reason, I think, we have concluded 

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from bot h problem s wit h est in, a tin g what the: 

We don' t hav e any det: : of longitudina l nat u 

hanqo ? 

in usin g a s 

•Jbi i L- h a i- . 

W i t h - r e d u c t i o n s in air g u a 1 i t y, w h a t h a p p e n = t c- th e? :;:: u r f a. c e s 

that are accessible? 

S'O I think our preferred path is; to try to assume? 

what the baseline is in the area the be?st we.? 

robust a data set, using all available data:,, 

in here the soil-lead as a constant and vary, with air 

q u a 1 i t y, w hi a t w e c a 11 t h e d u s t -1 e a d, w h i c 1i w e d e s c r i b e a s 

that being immediately deposited on the surface, which we 

think should be fairly contemporaneous with air-quality 

1 evels. 

We feel this would be the rruost reasoned approach 

around this part's total data gaps we have. 

DR. von LINDERN: I think that is correct, 

certainly. 

The other complicater—and maybe we have one of 

the few sites where this becomes a serious complicater—is 

that soil below the source itself, in addition to air. 

MR. HAINES: Yes. 

DR. von LINDERN: It also gets into the pathway. 

So what you are seeing in the home as house dust and so on 

has come from that as well as from the airborne. 

MR. HAINES: This is from re-entrainment sources. 

Hopefully, this is where your air quality comes in. .As that 

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I. i_ I L.». C*I J. t; ' L f other 

dust is' re-susp ended to settle out in the homes, it 

r e f 1 ec t ed on t lie mon 11 or 5. 

DR. von LINDERN: There arepathways that at least we deal with. 

One is actually tracking that material into the 

home, and another one is pets in bringing that material in. 

This; is never seen in the air-quality monitors. 

DR. McLAMB: We? captureci that as muc h as we? cou 1 d 

in the analysis we did >on soil, air, and Ice ad dust. In thee 

household dust equation, we do have an unexpl an able variable? 

of soil which can, I believe, capture what you are referring 

to. 

MR. COHEN: Katie raised an issue—-I don't know if 

anybody has any data; we might as well ask while we? are 

here on core-size particles that would not be collected by a 

high-volume instrument. 

MR. HAINES: This is basically for distribution of 

core particles. 

MR. HOFFNAGLE: The dust-fall-bucket data includes 

something larger than the high-volume sampler, but you cannot 

get a particular size on it. It is certainly not done 

routinely. 

MR. HAINES: The best way to come up with a 

response to the issue is to take an amount of lead and look 

at the distribution of particles, per se, and assume that 

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G I si r i bu t i on s 

t c b e.- !•. a \ e- s :.:• fv. e t h i n z\ I :- k ev t h s. t f r o m t h e? s e gener a I i :•: e? ci 

iciuse we dor ' t have it for 1 e ad •-• spec i fi c that 

aware of. 

We could not find any when we attempted to address 

HOFFNAGLE: distr i but ions, o 

course, in the? e?mi ssi ons, and they are measured. 

MR. HAINES: Unfortunately, from the point of view 

of the? principal sources now being futured in the storage 

pi leas, I think we even have sparse data there in size of 

that. 

As we look at the world today, the stacks if the 

c co n t r o 1 s a r e o p e; r a t i n g a r e r easonably well — c ontr oiled and 

probably are not having a significant where we are seeing the 

high blo'od levels in the children, which are quite close. 

All we have is a fugitive dust problem: either 

process fugitives coming off or handling, yard contamination 

being re—entrained. 

I am unaware that those particles have ever been 

sized. 

CHAIRMAN LARSON: That is a challenging and 

difficult problem, more difficult.than it seems. 

DR. MAHAFFEY: Could we turn general for a bit? 

CHAIRMAN LARSON: That is fine. I was just going 

to suggest that we go to each individual member, perhaps 

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starting with you, to give us your gtanev al impres-hons of thee 

report„ 

DR. MAHAFFEY: A long time agio when we started 

some of tiiis, one iof the concerns had be?en talking about a:u -

1ead/b1ood-1ead ratios because while there is something that 

traditionally, perhaps, has been done, there were some major 

reaisons for doing just that. 

Included in these reasons were the fact that it 

seems simplistic to look only at air with the realization 

that the lead and air winds up in the street, and this was 

back when the streets were containing 3,000 and 4,000 parts 

per million lead because of lead in gasoline. 

So the need to pha.se down lead in gasoline? was 

recognized. No one needs to hear that history again. 

But we still are dealing with trying to look at 

air-lead and dust-lead. One of the questions that stands out 

to me in this modeling exercise—and this is not really to 

speak harshly of the model, but to really ask where is this 

going—is you have to question what kind of generalizations 

can be drawn from this model: Where can it be applied? 

We live near, not too near, a plant that has had 

some problem with uranium discharges. If you are talking 

about particulate airborne whatever, there is a temptation to 

use this model that it may well not apply very directly. 

I think maybe some of this has happened a bit over 

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time . When we stair ted worryin g about 

goes and i t winds up i n th e street , we wer e really , at tha t 

time , more concerned wit h c.n urban env i r orii<ie?nt and how much 

lead was winding up i n the stree t fro m gasolin e emissions . 

I am making some assumptions here , but one 'Of th e 

r eason s you were- using t h e sme 11 er -s i t e i n f or mat i on >on t h e 

towns i n Montana i s becaus e they ar e characterized , because? 

ther e te:r n u ii V o be dat a t o 1 at these and an absence of 

data is one of the major problems throughout. 

The kind of discussion was had on which layer of 

t he s o i 1 and dust r e? fleets long-term lead e? m i s s i o n s that ha v e? 

wound up in soil. Contrasting these with the current aiir 

level is one kind of correlation ratio regression, whatever 

kinds of, analysis you do with it in trying to estimate 

exposure. 

You are relating this back t*o an internal marker 

of those blood-leads that only in part reflect current 

exposures. There is one sentence back in here that even with 

the be?st situation in terms of environment measurement you 

could explain 30 percent of the variation in blood-lead. 

This tells you there is an awful lot missing. 

This is even with the best situation. 

So I think in may ways what has been done with the 

model is close to as good as we know how to do right now: 

that there is a serious absence of information to work with. 

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o I p r o b 1 e m. o uncn 

t h e fac t i ....i >..' 1 1 • p., 

extrapolate d i n term s o i iothe?r kind s of envi r onfiie?i";tai 

problem s .-of, i f i t is , her e ha s t o be rea l y ecogn i 11 on o f 

what p ••< r t s o f i t c a n a n d c a r, n o t b e . 

Tha t i s a poin t I reall y wan t t o emphaei ::;e„ 

I thin k anothe r proble m i s tha t whi il e we are? 

intereste d i n b i ok i ne t i. c s yoLi cannCJt f or ge t t he b i o 1 ogy , t he 

physiolog y tha t undermine s the? biopar t i n biokineti c 

modeling . They ar e d i f f i cu1 1 issu e s . 

Yiou a^r e a11 empt i ng t o us e i n f or mat io n tha t came 

fro m adul t male s i n tryin g t o extrapolat e thes e kind s o f 

patters n o f exposur e and th e distributio n o f lea d withi n 

physiologica l system s t o women, i n particula r pregnan t women, 

and transfe r o f lea d fro m th e mothe r t o th e feat us . 

We kmow tha t th e lea d i s transferred . Ther e are 

cas e report s tha t tal k abou t congenita l 1ead poisoning . We 

kriow a littl e bi t abou t this , bu t we reall y d'on' t know ver y 

much abou t i t excep t tha t i t happen s and that , give n th e 

longitudina l studie s on neuro-behaviora l effect s o f low-leve l 

lea d exposure , liow bliood-lead s ar e quit e important . 

We d'on' t hav e much experienc e wit h tryin g t o model 

exposur e i n differen t bod y compartment s o f lea d a t thes e lo w 

exposures . Ther e jus t i s no t much ther e t o wor k with , excep t 

tha t we know tha t i t i s ver y important . 

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3 U ci Lj •::-• 1 i I ;hink tha t thi s has be ejmphasized i n 

t hi e cl i s c u ••::• s . o n 

.. ;..i o r i • i, 

i c pr i.ob 1 em. 

want t'O r.eally gi.o on with the 

I realize that you are trying to solve; a 

But I want to caution strongly against trying t'O 

extrapolate this model more broadly than I expect will 

happen. 

CHAIRMAN LARSON: Why don't we go around the table 

and let people share? their general impressions of the docket, 

chapter by chapter, member by member, I guess. 

Would you like? to start, Dr. Chisolm? 

DR. CHISOLM: Well, I think an overall comment is 

that given all the unknowns and all of the variability, you 

probably did as well as you could. 

I think one of the biggest variability in all of 

this is the relative amount of soil that children will eat 

and whether or not we compare Dutch children. 

I am reminded >of a quote from Rudy ard Kipling to 

the effect that those who consider cleanliness second only to 

godliness have a damn low opinion of godliness. 

[Laughter] 

I think the Dutch might place it a little higher 

than many segments of our society. 

To me, that is the biggest uncertainty because it 

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1 i s be?ha-v:l o: al . You ar e talkin g about biology , but i t i s a 

2 behaviora l difference? among children . 

3 You reall y h&ve t o giv e fairl y broad leeway t o 

4 that , I think . 

CHAIRMAN LARSON: Do you fee l tha t th e number s 

;hat were presented ther e captur e the range of uncertainty ? 

D R. C HIS 0 L M: l a m n o t sure about t h at . S u p p o s e 

je see the stair—step children in town. You can get a wide 

c i r cum stances. 

You may say that it is the two-year—old who has 

the highest blood-lead, but that is not always true. I 

sometimes wonder about why I say the five-year-old might be 

much higher in the same circumstances. 

15 I can think of all sorts of things. Maybe her 

16 father was; not the same as her husband, you know, and this 

17 kind is rejected. 

18 I am just saying that there are a lot of 

19 behavioral differences that make for other massive 

20 differences . 

21 I recall a child we had in the hospital no more 

22 than about six week s ago with a blood-lea d in, I think, the 

23 middl e 60 s and yet her sibling s were not over about 20 . They 

24 lived in the same circumstances. 

25 So ther e has to be somethin g about that particular 

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individual. Often we see a broad range. 

I don't think it is com (it on to see children living 

in the same abode with blooci-lead::? ranging from SO to 25,. It 

is not unusual at all. 

I am talking about children in old houses. It is 

the same general exposure for everybody. So I d'on't know 

that it real 1y was contrary. 

In East !-!e 1 ena, thiose are fairly we 11 -•• to—dCJ 

people. They are? not puur people, .1 don't think. There are 

a lot of socioeconomic differences. 

There are difference-as, I think, in the degree to 

which mothers of different ethnic backgrounds will tolerate a 

1 o t o f excess h a n d -1 o - m o u t h a c t i v i t y. S o I t hin k if y o u w e? r e 

to go do this study in, say, several sect i pons of Boston you 

might come up with quite different answers. 

That would be a reason for not extrapiol at i ng what 

has been found in North Holland or what has been found in 

East Helena to the whole population. 

I would also say, try to grow some grass in the? 

back yard where you have young children. 

CLaughterl 

CHAIRMAN LARSON: That is a challenge. 

DR. CHISOLM: It is. 

So I think your comment about the surface soil 

being constant is well taken. 

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MR. HAINES; Do you want L\.\ to interject any 

observations? 

CHAIRMAN LARSONs Any questions? 

MR. HAINES: Two points. 

Going back t>o the variation, we have two stages 

here. Is the modc-?l recognizing there is going to be a wide 

degree? Have we captured well eriiough that we can predict a 

mean recognizing that we €\rc-. going to apply the GSD on top of 

that mean to try to capture the variability in it and the 

fact that the GSD derived from the East Helena work is 

similar- to what is derived from NHANES? 

It is independently arrived at. It may be a 

perfect tool, but at least we are trying to interject in that 

variability what you are seeing. 

DR. CHISOLM: I just wonder if you have enough in 

it. 

MR. HAINES: Yes. 

I am not sure how to approach it other than what 

we are doing. We are trying to get at that problem through, 

really, a two-stage approach. 

On the uptake side, on the use of the Dutch data 

it is my understanding the way Jess applied that is basically 

use those children they looked at in the hospital itself in 

conjunction with Binder to derive the true baseline.' 

Is that the best way to say it, Jeff: for a better 

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MR. COHEN: BiMber, the n c::,:.t-,bL M I dietar y 

absorptio n of thoMa elements. 

MR. HAINES:: Yes. 

M R. C 0 H EN: That is a b i. g c h u n k o f the p i c: t u r e. 

The ori 1 y data t hat v.;e had that we t hought we c ou 1 d easi I y 

app I y t o that was the CI ausen data: c h i I dr en who were not 

r o 1 1 i n g a r o u n d in the c! i r t . 

Until the data from the ongoing studies are 

available, I don't think we? can really address that in any 

other way. 

I don't think it would be appropriate f'or us to 

use the dirt ingestion rates that Clausen found for those? 

children. I agree there is probably a whole different set of 

b e hi a v i o r s b e t ween t h e t w o k i n d s o f p o p u 1 a t i o n s. 

We have tried to use the Binder study, but using 

the Dutch data to adjust for the unmeasured trace el cement 

absorption. 

DR. MARCUS: One more comment on the variation and 

the cultural f ac t or s. 

Some of the Cincinnati studies, published in 

EQlti*120n*<=oJi.§I E<=search about three years ago, actually showed 

how various subscales of the Caldwell Home Index 

quantitatively mediated theh dust-lead to hend-lead to bloodlead pathways. 

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muc-1- , h aware? of tha t 

tha t 'only 30 percen t 

Tha t i s th e 

o f t h e v a r i a r i c e? i ;::• 

We are ve 

reason , a s was said , 

expla i ned . 

' A s fa r a s thes e models ar e concerned , thi s is; t 

reaso n why we belie?v e tr I fc? y r:t r e reflective of typical ..lues 

in p'Opul at i ons of children. I believe we are aware of the 

limitations in using them as a tool for predicting individual 

chi 1 dr en' s bl iood-1 eads. 

There at re a lot of sources of variation. 

DR. CHISOLM: I was not putting it that way. 

DR. MARCUS: Okay. 

DR. CHISOLM: I was putting it more 'on different 

social strata and different ethnic groups that take quite a 

different attitude ion it. 

DR. MARCUS: Yes, sometimes even in the same 

location if this were to be applied to populations about 

which one had relatively little such baseline information. 

MR. COHEN: There is one other point that Katie 

brought up on the lack of biokinetic data during pregnancy. 

We are left with estimating blood-leads f'or that 

population using air bl cod-lead slopes derived from male 

studies, basically. There is a real problem with that. 

We are not using any biokinetic adjustments f'or 

that. 

DR. MUSHAK: In 1985, we had a jioint conference. 

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Marco Zarech discussed dat a fro m a villag e i n Yugoslavia . 

They had a se?t of women who wer e studied , serial , 

fo,- blood-le?ad. T believ e thei r leads ar e availabl e for tha t 

period , and probabl y dust-leads , also . 

So that i s a group which can probabl y be probed i n 

much c 1 osei" detail . Vou might want t o chec k wit h Graziano 

f r o rn C o 1 u in b i a. H e p r- Q b a b 1 y h a s al l o f t h a t prog r a m. 

f -1R. F L A A l<: There was hig h lead i n part of i t ? 

DR. MUSHAK: Reason ab1y . 

DR. MAHAFFEY: They had a coupl e differen t groups , 

didn' t they? They had differen t environmenta l location s of 

b1 cod—1ead exposure? 

DR. MUSHAK: Right. 

This is a subgroup in which pregnancies were 

followed and the?y were serial. There were something like 7 

or 3 points each month of their pregnancies. 

DR. MARCUS: There is also the Manton isotope 

data. 

DR. MAHAFFEY: That is only .on two or three 

people, though, right? 

DR. MUSHAK: Right. That's what we" are left with. 

.MR. HAINES: Five female subjects in the Dutch 

study, but that was for a very short exposure. 

DR. MAHAFFEY: As I recall that data, did their 

bl 'Ood-leads go up faster or they had a greater response f>or a 

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give n b1o o d-1ead? 

Ther e wer e definit e difference s between the? 

a n d f e? m a 1 e s u b j e c t s . 

DR. MARCU! 

MR. HAINES: This raises a sort of provocative 

question from our point of v i ew. 

We recognize the limitations of trying to estimate 

maternal blood-leads. Part of our dilemma is we? have? 

identified the fetus and are trying to trigger back. 

When we try to make use of the data, it may be so 

inappropriate that maybe we should not be attempting to use 

these models to predict that relationship between adult 

females' maternal blood-leads. 

CHAIRMAN LARSON: That is the sense of what I ant 

hear i ng. 

MR. HAINES: What I don't want to do is attempt to 

take what very limited data we have, try to apply it, and 

then say, "No, we should not be doing it." The better 

response may be that we cannot make those estimates at this 

point in time and we ought to focus on children for whom we 

can do a reasonable job of estimating exposures. 

DR. MUSHAK: I don't think anybody is saying that 

the pregnancy tail should be wagging the exposure-analysis 

dog. If you have the information, use it; but keep what you 

have. 

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MR. HAINES: Okay, according to the caveat of the 

limitations of what we are doing. Okay. 

I just want to be? clear on that. 

DR. MAHAFFEY: I reviewed a lot of the lead-inp r e?gn anc y i n f or mat i. on f or somet h i ng that we ar e d oi ng at NIH. 

It is clear that while the cord blood —leads art? 

very close to the maternal bl ood-1 eads, there are a l>ot of 

a c J d i t i o n a 1 c o m p a r t m e n t s. Y o u hi a v e t o take in t o acco u n t t h e 

amniotic fluid, the membranes the placenta. 

There are different components here that may not 

really agree that well with the maternal and the cord bloodlead. ' That part is not wel1-studied. What we know may be 

really based on lead poisoning pathology cases. 

So I think Paul's point is well taken: that you 

don't ignore the issue; but that the other side of this is to 

recognize, and be very up front about, that these are just 

basically best estimates in the absence of data for the group 

of concern, recognizing the Manton data that shows that bone -

lead does contribute and whatever you can .obtain from the 

Yugoslavian experience. 

DR. MUSHAK: I think you might also' add the 

paradoxical effect that you get in the Australian subset 

where you find that fetuses apparently are serving as a sink: 

that is, with higher lead exposures. You get lower bloodlead levels in women. 

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That i s writte n up i n Mike Davis;' paper . That i s 

going t o be a furthe r problem : why you canri'Ot us e an end. 

CHAIRMAN LARSON: Okay. 

Ian, would yiou like t'O summarize. I know you have 

already share d w i t h u s s o iii e o f y o u r t h o u q h t s. 

DR. von LINDERN: We have heard this before. I 

think it is a good job and I think it is as comprehensive as 

it can be. 

I -spent the last year trying to do this for one 

site and it has driven me nuts. They are trying to do it f'or 

the world. 

C Laugh ter II 

I have a couple of things to share. I think Dr. 

Chisolm's comment is very appropriate. On our side, we have 

developed a risk profile for children who are typical and 

those who are what we call high risk, and they are the ones 

that we have to worry about. 

We have done the back calculations on ingestion 

rates. By the way, Region 10 released that document on 

Friday so you guys can have copies of it. 

At our site, it looks to us like 50 milligrams per 

day soil ingestion might be appropriate for the typical 

child, but when you look at the high-risk child, the child 

that we are concerned with protecting, it runs up in the 100 

area. 

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Region 10's position on that that they are 

offering out at this time is that we are going to use the 100 

milligram per day value?. Si.o the?re? is a. wide? variation and it 

d e p e r i d s o n t h e v e? r y fa c t o r s t h a t Dr. C h i. s o 1 m is t a 1 k i n g 

about. 

011 'i e r c o m m e r 11 s s T hi e a i r -1 e a d t o s o i 1 s a n d d u s t 

thin g doe s bothe r me . I thin k tha t i s a very difficul t one? 

to do. 

As I said, the relationship of the smelter 

situation is as to what has gone on at that smelter over the? 

last 30 years and mot what we are measuring today. 

The other thing I mote in the smelter that I need 

to explain a little better, that was in my comments, was not 

•only is lead uptake related to the soil concentrations that 

we see in children's yards, but there seems to be another 

factor as well that, for us, seems to be explained by just 

the general level of contamination near the smelter. 

Maybe the other soils that children can get in 

contact with in addition to the ones specifically measured in 

their own yard and dust conditions in streets, and so on I 

think are important factors. 

Carol Engel, I think, noted that in her papers. 

The community exposure ended up being more important than the 

individual's yard exposure. 

The other ppoint I have not heard much >on—and I 

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don't know if this is the appropriate? place, but I think we 

should say it—ha?? to do with the nnoni t or i ng frequency of the 

NWAQS. 

I think the one that is in place now for a 

situation like ours is almost totally inadequate. That is a 

measure once every 6 clays when we probably have about 11 days 

a year in which transport of material into the homes and dust 

s t o i" m s i s o u r critical variable. 

W e don't measure that. 

I think it also should be looked at in terms of 

upsets and malfunctions in smelter situations. Region 6 did 

an analysis back in 13S4 at the Teflus Smelter which you 

might want to take a look at, in which. I think it was 45 

percent of the total exposure over a three-month period was 

associated with one upset at the complex, which was actually 

tied back to 5 minutes of a fan being off. 

A short-term event can end up causing quite a bit 

of the exposure that we see in the community. Those are the 

types of exposures where larger particles get out and get in 

the house dust. 

My other point was I think as much 'as we wish to 

say that this is an air-quality situation, I know there is at 

least one person sitting at this table and several in the 

audience, I think, who are probably as concerned with how 

this is applied to soil clean-ups in the country. 

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I think we should all recognize that this can be 

used for that and some of the assumptions that we make should 

bear that in mind. 

CHAIRMAN LARSON: Do y ou t h i. n k i. t i s ap p r op r i at e 

f o r t h a t a p p 1 i c at t i o n : s o i 1 c 1 e a n—u p'? 

D R. von LINDERN : Absolutely . I thin k it is th e 

best that there is, but y'0u have to make assumpt i ons. 

CHAIRMAN LARSON: R i gh t. 

DR. von LINDERN: You need to evaluate? those 

assumptions in terms of what the ultimate remedy is going t'O 

be applied here. 

CHAIRMAN LARSON: John, did you have some 

questions? A comment? 

MR. HAINES: I would just make the observation 

that we are concerned about the monitoring issue. We? will be 

addressing that in the staff paper both with regard to 

monitoring siting requirements and to the frequency of the 

sampling. 

Early next year, we will be laying thatt out in 

staff-paper fiorm and, later, looking at needed revisiions to 

the air-quality surveillance requirements. 

MR. COHEN: I have >one more comment. 

The fact that community exposure, not necessarily 

home-to-home yard-to-yard soil-lead levels, may be miore 

predictive or a better surrogate for integrated exposures, do 

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you think that would tend to support our use of the 

data that we identified from all sorts 'Of situations in the 

appendix there as opposed to the East Helena data set where 

the soi 1 c oliec t i >olis were done f or eac h house? 

One of the? '.other studies that thev went out ; °o i 

a park 'Or a playground, for example. 

D R. von LINDERN: I d on't n ecessar i1y b e1iev e t hat 

it is a better one. I think it is an additional one. 

I think that in the pathways it would reflect 

that: that children are exposed in their own home yard and 

house, and they also get out around the neighborhood and get 

i nt o the other sour c es. 

So I think they both should be used. In fact, we 

have made an attempt to use both of them in the Region 10 

analysi s. 

CHAIRMAN LARSON: Okay. 

Dr. Clark? 

DR. CLARK: Most miodels show that it is the uptake 

from the soils and the dust that get to the children. So 

seeing that once the lead is in the dust or soil, most of the 

model is the same regardless of how the lead got into the 

dust. 

I think some data on relationships from other 

studies can be useful in the model tpo extend the range of it. 

We have done that by applying our model to data from 

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Cincinnat i and 

- f i |.. . i„ i.. 

s 1 o p e s , b t.t t the n i o d e 1 

•. p p 1 -:' v e r y well . V o u get d i f f e r e rt t 

s t :i "; 1 work?.-: tha t the? model fro m th e 

lead arid the surfac e and the soi l int'O the dus t i n th e home 

o n th e c h :i. lei' s hands , t hi e n b 1 o o d- 1 e a d . 

S'O we: probabl y coul d us e other data i n here on 

tha t piortion of the pathway becaus e th e lead fro m th e soi l 

coul d be fro m 30 years ; iof activit y pof th e mil l or th e mine, 

or i t coul d be? fro m 30 year s or .1.00 year s of pain t 

cie?posi t i on , aut omob i 1 e exhaus t over t he patst sever al decades. 

T hi e r e i s s o m e p r o b 1 e? m w i t hi d i f f e? r e? n c e s i n th e 

availabilit y of th e lea d i n th e differen t forms, but we thin k 

pr obab 1 y mor e d.at a c ou 1 d be used i n th e m o deling . 

I thin k there is; a major impact pon what i s going 

t o happen on soil-lea d criteri a for clean-up . I thin k that 

i s th e ultimat e area where we aire going t o have an impact 

because th e exposures directl y from th e ai r are not that 

grea*t now. 

I t i s th e past ai r exposures where th e healt h 

effect s ar e occuring . 

DR. MUSHAK: What i f you ar e d'Oing a befor e and 

after ? 

DR. CLARK: But i t i s what happened i n th e past , 

i n term s o f th e air , where most o f th e healt h effect s are 

occurring . I t i s residual s of former air-lea d level s >or 1 eatd 

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f r o m o t hi e? r s o i.i r c e? s 

We hav e a measur e tha t we prefe r on S'O: I s a 

surface scraping. Some folks think it is just a horrible? 

m e t hi "0 d s c i e n t i f i c a 11 y, but it w o r k s. 

11 i s a s c r a p i n g o f f a hi a r d - p a c k e d s u r f a c e? o r 

paved' area. That is where the child has access now. 

It is now d'own 1 or 2 inches. That could be 

important in the liong term, I agree; but the current exposure 

is what is on the surface. 

We have had a hard time convincing Rob Eli as to 

let us use? that in addition to the soil. We are going to do 

our soil cores, the top couple—the top 2-1/2 centimeters, 

then 15 centimeters—but, also, we are going to use a surface 

scraping, which can be used both for hard-packed or any kind 

of soil because the child still is ion the t'op and the top is 

where the higher levels are. 

DR. CHISOLM: From your point of view, as I 

understand it, if you are thinking in terms of the l>ong range 

and if you keep scraping it off and you are boring int"0 a 

layer where it does mot change for X somometers, you would 

not be placing quite so much emphasis on just the surface 

scraping, I would not think. 

If you come back and scrape 10 years from now you 

would get the same thing, I think. 

MR. HAINES: This is part of the dilemma of 

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finding what is accessible. As that penetrate?? down, dioe?s it 

really, in Tact, stay there':-' 

I think in situations it may stay in place?. In a 

dirt school yard it probably will not stay in place because 

t! J e c I-i i I d r e? n w i 11 c o n t i n u all y c h u r n i t u p a g ai i n . 

T h e?, q u o t e?, a c c e? ssibil.it y p r o b 1 e m t h a t I t h i n k w e 

aire dealin g wit h is wha t trul y is accessibl e or not . 

DR. CHISOLM: You have to think 1 ongitudinal1y, I 

thin k. 

DR. McLAMB: Yes, that is what I mean. It will 

vary. 

CHAIRMAN LARSON: Allan? 

DR. MARCUS: On this accessibility, I think fior 

perhaps risk assessment purpioses a conservative approach 

regards the sioil in the core, at least for a few centimeters, 

as accessible, a potential reservoir pof lead that can be 

brought to the surface. 

A lot of pe^ople both in rural and urban areas keep 

big dogs. They dig holes, our children dig holes in the 

yard. People put in cable TV. 

There are a lot of things that would make soils in 

habitations accessible to a depth of at least a few 

centimeters. This is the reason why the most conservative 

approach would regard even those sub-surface reservoirs as 

potentially mobile. 

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DR. CHISOLM: As one measurement, not as the total 

rn e a s u r e m e n t . 

DR. MARCUS: It is just one measure, and these 

have? different purpiose?s. 

I f you are try i. n g t o 1 ook at c ur r en t b ] ooci •- lead s , 

the immediately-accessible part is the part right there at 

the surface. If you are looking ahead towards how this or 

any other model would be? used for clean-up, I think you would 

have to regard the potential accessibility of the sub-surface 

soi1s as wel1. 

As I suspect this or related models will be used 

for risk assessment purposes, those differeances in purpose? d>o 

have to be clarified. The generic relationships that were 

developed may need to be refined for particular purposes for 

other applications. 

As you say, we are looking for areas primarily 

around point sources where there has been an historically 

high deposition. Other purposes will probably require other 

refinements. 

That is all I can say. 

CHAIRMAN LARSON: I have a question. 

The other pathway which you mentioned as included 

in your model, on which I was not clear, was the soil-tohouse dust route. You had a term in your regression for 

soil, but that was a total soil sample rather than a surface 

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1 soi1 number. 

2 MR. COHEN: That was surface. 

3 The measurements were derived from outdoor s>oi 1 . 

4 DR. CLARK: One of the tables , I think, was street 

5 dirt and soi1. 

6 MR. COHEN: Yes. 

7 It is really surface-to-surfac e layers that may be 

8 1, 2, or 3 cent i met er s, not going any far the?!" than that. 

9 CHAIRMAN LARSON: Is that the same surface that 

10 you we?re referring to'? 

11 DR. CLARK: Well , no t really . 

12 Actually , our surfac e i s reall y what we can scrap e 

13 off with a spatul a on a hard pack. It i s surprising : you can 

14 ge?t a reall y quantitativ e measure there . You don' t di g down 

15 in. 

16 Most soils where children are are not loose. You 

17 are not going to find many school playground s where it is 

18 like a garden. It just is not. 

19 The hous e dust is alspo a critical component. It 

20 can be tracked in by children or pets, be brought in by wind, 

21 whatever . It does not have to be that child, it can be an 

22 adult. 

23 But the pathway appear s to be very clearly from 

24 the outside surface, inside surface, to the hand. Regardless 

25 of how it got on the outside surface, that is almost 

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availability . 

0 H AIR M A N L... A R SON: 1 am t r y i n g to get a s e n s e as to 

what extent does a relatively rapid change in an air level 

ref' 1ect on your compartments. 

D R. C L A R K: P r o b ably v e r y I i 111 e, d e p e n d i n q LA pon. 

If we? we r e ci >o i n g t h i s 3 0 years a g o, i t w o u 1 d be d i f f e r e n t; 

but not now. 

You would not me a?? ure it in (most cases. In any 

urban area you would not measure it, I don't think because 

t hi e r e s e r v o i r i s s o t r e rn e n d o u s. 

M R. HAINES : Wha t we? are reall y talkin g abou t i s 

what is a reasonable approximation: Tim's question of how 

much of thi s is- 1 aid-down, quote, soi1-1ead that may be 

tracked in by the pets and children; how much of it is 

interior dust related to contemporary deposition and, by 

"contemporary" , at leas t durin g tha t perio d of time . 

1 guess we are taking the approach, absent anybody 

partitioning that out, apportioning it, that the dust 

measurement inside is fairly contemporaneously related to the 

air-quality level. 

So we feel that is a reasonable assumption that as 

you bring down air-lead levels that dust will move with it in 

a simultaneous fashion. 

DR. CLARK: We have seen, I think, some remarkable 

decreases in the past 3 or 10 years in our surface 

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measurements inside and outside? the home. There is a 

definite lowering that has to be associated with something in 

the air or outside. 

Now, it is going to tail off. It is tailing off 

n o w. 11 i s h a r d e? r t o s e? e? a n y m o r e? c h a in g e s. 

There is a 50 percent in almost all of our areas? 

whether it is in the public housing areas or in the? older 

housing areas. S>o something is happening besides changes in 

the house. 

MR. COHEN: Are those data summarized? 

DR. CLARK: No, they are not. 

Well, they are in some reports. We don't have 

them published yet. 

MR. COHEN: Okay. 

DR. CLARK: We are seeing the decline in bloodleads and all of our pother measures. 

MR. HAINES: Can we compare that to reductions in 

gasoline lead? 

DR. CLARK: You could, sure. It is par al 1 el i ng 

the change in the lead additives usage. That is the past 7 

years or so. 

DR. CHISOLM: Are they tailing off toward the soil 

c one ent r at i ons? 

DR. CLARK: Oh, they are leveling off. The 

decrease has been less in the past year or so. 

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DR. von LINDERN: Are any of those sites near 

the s e p o i n t s o u r c e s'? 

DR. CLARK: No. Maybe siome very small points, but 

nothing major. We have some lead industries. 

A year and a half ago, we had a small foundry ... -; t h 

about 100 employees that had almost every wiorker with 

clinical lead p'Oi soni ng. 

They were making poor man's peuter: the old 92 

p e?r c e?n t 1 ead p eut e?r . 0n e? '0 f t hi e 1 oc a 1 i n d ustries d ec i d e?d 

this was; a nice gift to give their employees atnd retirees at 

Chr i st mas t ime. 

So the orders from this foundry increased 50-fold. 

They had mo controls in the plant, no showers, and people 

carried enormous amounts of lead. People are still being 

affected by that. 

There are some adults who are actually going up in 

blood-lead after a year and a half, just a very major source. 

That was in a suburb. I didn't have much impact on the city 

i tself. 

DR. MUSHAK: You are looking at the children, too? 

DF:. CLARK: Nobody has concertedly because it is 

all over the place. 

DR. MUSHAK: They are a perfect target. 

DR. CLARK: The health department was looking at a 

few, doing some screening, and we have screened and tested 

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some outside of 

measurement??. 

DR. MUSHAK: Judging from the lack of occupational 

hygiene, I would say that the homes of these workers would be 

most affected. 

DR. CLARK: Oh, yes. There were some children who 

were affected. One mother in particular, I know, was 

pregnant working at the foundry for the whole pregnancy. The 

child is in the SOs or SOs and has developed mental problems. 

This was a person living in a mobile home 50 miles; 

in the country. 

CHAIRMAN LARSON: I have my Chairman's hat on here 

looking at the agenda. Maybe? we can get the discussion 

started in full gear again after lunch. Perhaps you can hold 

your comments until them. 

I f we break fior lunch mow and return at 1:30, that 

will give us an hour to complete our discussion here and then 

have a chance to hear about the case study applications. 

Okay. Thank you. 

CAt 12:30 p.m. , th e meeting recessed t o reconvene 

a t 2:0 4 p.m. , thi s same day . 3 

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AFTERNOON SESSION 

CHAIRMAN LARSON: Why don't we reconvene. I think 

we are moving along adequately still trying to stay on target 

fpor 4:00. U!e will pick up where we left off with additional 

comments on the general 'document. 

Dr . Raibi nowi tz? 

DR. RABINOWITZ: My fortune cookie said that "If 

you eat dirt, you should eat clean dirt." 

[Laughter 1 

The document is commendab1e. 11• i s a difficult 

task and I think the authors did as well as they could with 

the gaps in the information. 

I guess that is it by way of general comment. 

Just having the discussion now is helpful to me to 

kind of see where this is going. That is one thing I missed 

in reading it through the first time: Why are we doing these 

different models, and what is the purpose of all this? 

I am sure the next draft will have that all taken 

care of. 

CHAIRMAN LARSON: I think we have an opportunity, 

perhaps, to get a final set of comments after we hear the 

later presentations this afternoon. I am sure you will have 

some other reactions to share after you hear those. 

Dr. Mushak? 

DR. MUSHAK: I thought the report and the whole 

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r ef ] e •: t s t hi e g r o w t ! t o f s •:•• p hi i s t i c a t i o n i n h o w t h e 

E n v i r o 11111 e i' 11 a 1 !::' i" o t e? c t i o n Agenc y i s g o :i n g a b o u t i t s b u s i n e s s . 

About 11 years ago, I sat down with a group of 

0AQPS t ype?s t o t ake a 1 ook at ar t i c u 1 at i ng a st ar t egy f or an 

ai r - 11-.?a:'.cj standard. Basically I guess you can encapsulate the 

gist of it in about two paragraph??: forgeet page after page of 

rigmarole, just the essence of it was two par agraphia. 

H a v e? s o m e? t hi i n g >o n f r e q u e n c y d i s t r i b u tion , 1 o o k a t 

s o irt e t h i n g a b o u t e? v e r y t h i n g e x c e p t air an d get a P B A lette r o f 

about 2 and you ge?t 1.5. 

We have come a long way since then. The report 

has probably taken the parameters as far as we can g>o with 

them, but I think we ought not to bash the uncertainty 

because I think that it has been said by public health types 

all the time that there is compelling evidence and then there 

is irrefutable evidence. 

Thatt is, once evidence is compelling we ought not 

to insist that it be irrefutable from a public health 

protection stance. 

This is a stance which I think the Environmental 

Protection Agency is, both legally and morally, mandated to 

practice. 

Also, I think needs are both compelling and 

irrefutable. I think that a model like this is a compelling 

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need. 

A b o u t the p o p u 1 a r i t y o f the m o ci e 1 f o r c • t h e r 

application — i.e., a global or generic uptdke bi. oki net .1. c 

model — I would Bee some utility in, say, the-Be various cle 

ups. I think the clean-ups are a good way t.o test the n.oc 

because apparently in Julian's case in Boston, and in 

Cincinnati, pre- and post-blood-leads are being collected. 

I s t hi a t c o r r e c 1 ? 

DR. CHISOLM: That's correct. 

DR. MUSHAK: So you could validate the model's 

application with pre- and post-blood-leads to see how the 

prediction worked. 

I would also caution that if one is to use a model 

for soil lead—Jeff Cohen and I spoke about this briefly 

before—if you do something like a rather broad traversal 

down a soi1-1ead/blood-1ead slope you may be jumping from a 

non-linear part of that model's dominance to a linear. 

You might want to be careful. 

As I remember Ian's curves with the competence 

limits between blood-lead and soi1-1ead, you get extreme 

curvalinearity above, say, about 4,000 ppm. In other words, 

PPBs become quite curvalinear above about 4,000 ppm of soil. 

So one has to be careful what range of that 

hypothetical model curve you are speaking of. 

I think it is probably a good model for lead in 

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certain other contexts. I don't think it's generic model for 

fill-in blank A metal and then you can do it because lead, 

un f or tu r i a t e1y, is the on1y mode1 that is st udied well e n ou g h 

that I think you can do a model and base this on. 

01 hi e r a p p 1 i c a t i o n s o f t h e m o d e 1'? I g u e s s w e 

talked briefly over lunch about the prospect of pregnant 

women at term: look at newborn blood-lead modeling, some 

hybrid of Mike's early modeling plus the KMIF'E variation. 

That is something to consider. 

Or you could stick with the disaggregate model as 

you are doing now, but I think there is some? virtue in trying 

to model newborn bloods. You get at least one more 

d eve1 op men tai point. 

I think that in-utero exposure modeling is 

probably lost to you until there are some breakthroughs in 

non-hazardous in-vivo modeling of soft tissues. I don't see 

how t hat c ou1d wor k. 

The uncertainties have been considered. I think 

that 100 milligrams of dust/soil combined intake is certainly 

righteous. I don't think that numbers below this are really 

appropriate. 

There is much scatter in the dust and soil 

average, but I think 100 is — 

CHAIRMAN LARSON: As a mean value? 

DR. MUSHAK: As a mean value, understanding that 

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ther e p..;. r <* i i i '-.j'..'. i ; 

'e co rea . 

; ''-• £:v ar ounu i c 

that around i is mean thei e are 

dusk intakes, -soil intakes wh: car: be ouite nuqe 

scall that there were some SGLIGJ. e ;/s b aH:;ed or 

mineral trace elements that had gotten levels above a gram. 

W h e t h e i" o r n o t t h o s e are o u 11 y e r type 1 e v e 1 s b e c a u s e o f 

problems, I am not sure. 

I would say if you look at the evidence in the 

aggregate, 100 is not too bad a number. 

That is it on that. 

CHAIRMAN LARSON: Bob? 

DR. ROWE: I don't really have a lot more to say 

in terms of all the comments that have been written and said 

here in terms of conducting a rural point-source-oriented 

N A A Q S e x posur e asse ssmen t. 

It seems like that will be fine. My only comment 

is that in the ideal of ideal worlds it would sure be nice to 

know what even a small change in air would do in the urban 

areas because we would probably ultimately have more people 

affected. 

It may not be the most cost-effective strategy, 

but that would be nice. We are going to have just small 

people here compared to the urban-area problem, but that has 

been a previously-agreed-to decision and I don't have any 

problem with that decision. 

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S o , no , I thin k w e av e on track . 

102 

CHAIRMA N LARSON : I hav e a c ou p 1. e c ommen t s mysel f . 

J List from somebod y viewin g thi s model from afar , 

it woul d b e nic e t o se e th e prediction s from th e facilit y 

11-1 a t y o u a r e c o n c e r n e d w i L h o f t h e c o n c e n t r a t i o n s o f t h o s e 

environmental variables that a.re important in the ultimate 

deter minat i on of b1ood-1ead. 

Specifically if you have an observed gradient 

within a few miles of a point source?, can you also predict 

with your model the RUN C type of thinking, the air-lead and 

dust-lead now values that you see in the mean, perhaps, that 

you are using ultimately in the prediction. 

The reason I say that is because it becomes easier 

for the not—so—fami 1iar reader to distinguish between your 

model's ability to predict uptake versus exposure. You could 

potentially be right for the wrong reasons. 

I don't think you are, but it would be nice to 

have some of those intermediate mean values or median values 

in there as well. I think we heard some of that this morning 

in terms of those particular issues. 

That is one general comment. 

I agree, though, that you have come a long way in 

this particular process and that the observation of a 

gradient blood-lead, even in a limited area, and the ability 

to forecast it with some, at least, gradient or relative 

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a i l .i. • I»i—" -•" c'S':::., 

1 •; j..•. .• 

1 .p. •_• y , 

What I am heaving is that we are only talking here 

about forecasting mean values. I get some sense that if we 

played around with soi1—1ead averages or whatever, we may or 

may not be as good in agreement with these case studies as 

you see in this particular report. 

But, still, some notion -and I don't know how you 

do it — of whether or not your predicted versus your observed 

mean values at different points away from the source are 

d i f f e r e n t f r o m e a c: h o t h e r . 

I don' t hav e a g'-*"--.d feelin g for ho w t o approac h 

t h a t sinc e y o u h a v e an rang e of uncertaintie s an d not a 1ot 

of informatio n o n th e shap e of th e point s in betwee n an d th e 

range, but it would be nice to make an attempt to see?, even 

if the model and the predicted observed lead gradients are 

not quite the same, that there is some overlap there given 

all the uncertainties. 

Just sort of stepping back, it would be nice to 

see the intermediate prediction of, now, I guess we are 

talking dust-lead and air-1ead in the mean, and then the 

resulting forecasts for blood-lead and their uncertainties 

compared to the mean observed values, which takes us to the 

next point. 

Given some ability to predict that mean gradient, 

is it reasonable to take the next step, which is then to take 

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t hi a t me a n , o r mea n p r e d i •:: t i on , t r om t h e m o d e 1 a •• i d a p p 1 y a 

geometric standard deviation as is proposed here ;n terns •:.•'( 

forecasting the number of children, in this case, that a, e in 

excess o f X ti 1 o o d ? 

I w ouid be interested i n h earin g o111 e r Commit tee 

members' reactions to that particular approach to this 

variability issue. We have heard a lot about all the 

potential sources of variability in the actual data. 

DR. MAHAFFEY: I think what is puzzling to me is a 

c onc er n about whether or not t hese geomet r i c standard 

deviations would apply at extremely low blood-leads, talking 

perhaps blood-leads under 10. 

There is a little bit of information suggesting 

that you havie a different sl'Dpe in the relationship between 

environmental lead exposure and indicators of blood-lead, and 

that that slope will differ depending on the level of 

exposure. 

So whether or not you have that same standard 

geometric deviation across a wide range I think is 

questionable. 

That is just an opinion. 

CHAIRMAN LARSON: Would you expect it to be harder 

to characterize what the variability is? Is it that given 

the perfect ability to characterize it you would expect it to 

be different in terms of measurement, just approaching 

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measur ement'limits ? 

I don' t expec t an answer. I jus t thro w tha t out . 

I t i s strikin g t o me. I -don't know enoi.igh about 

t h e NHANES data set , b ut 1 am r ead i n g i n h eve tha t acr oss t h 

ki CP 1 e s p e c t r u m o f b 1 o o d -1 e a d 1. e v e I s i n t hat s u r v e y t h i n g * 

seem t o be log-normall y distribute d wit h a reasonabl 

constan t geometricall y standar d deviation . 

DR. M A H A F F EY: We di d not ha v e suc h 1o w 1e a d s i n 

that . 

CHAIRMAN LARSON: That is right. 

DR. MUSHAK: That is a key point: that the low end 

of the table by 1390 in the rural case adds maybe .25 or .5 . 

pier cubic meter. You would still be looking at something. 

I think the analytical varying problem remains 

severe. Okay. There is no reason to expect that good leads 

would perform any better than they can; they already are. 

And I don't think that poor leads are going to get religion 

any time soon. 

You have the analytical factor that is driven by 

that particular configuration. 

I think there is something about the 

pharmacokinetics of lead that may compel a log-normal 

distribution with a lingering tail upwards. You see this, 

for example. 

You look at food stuffs, anything that has a 

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b i ologicall y — i nt eract i ve 

d i s t r :i bi.it i on . The c one er 

c-t J. p'.JL|'""I ;'...pr iiii: 

ktr, part s pe; 

i I l i I o n 

When you look at air, what kind of distribution 

wouId vou see in 

::r!AIRMAN LARSONt i s J. oq nov (dai for the most 

par The vav ianee n proportion to the mean Ic-jve?! ., 

DR. MUSHAK; I mean at the level we are talking 

about, .1, . 2 . 

CHAIRMAN LARSON: I think at any level. I think 

you can slice it up how you 'want and it comes out to be log — 

normal, perhaps for a different set of reasons. 

MR. HAINES: It could be. 

CHAIRMAN LARSON: I would expect if you have a 

log-nor m a1 d ist r i b ut i on t h a t y ou wouid e x pec t t he abso1u t e 

variance to shrink as the mean goes down in a proportional 

way. 

It is hard to think in log terms. I guess we can 

see in log terms. 

DR. MARCUS: Actually, I think that is it. The 

variability in absolute terms does get smaller as the levels 

get smaller, but in relative terms for a lot of different 

populations over a very wide range of mean levels of bloodlead. 

If you don't like talking about geometric standard 

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• • -XT.: . 

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107 

deviations, you can convert it into a coefficient of 

vavi at ion, wh ich i 

tiie a n 

r. r a t J. o L.I i :t andav d devi at i on to a 

•ari ability fo 

a v cr-. v i e t y o f s o u r c e s, n o o n e 

It is a familiar percentage measure o 

blood —leads where yp"ju h&-

w ki i c hi i s r e a 1 1 y o v e r w h e 1 m i n g . 

This is the situation we are looking at more and 

more in urban and rural areas where lead in diet contributes 

s o m e t l-i ing a n d w a t e r -••• 1 e a d c o n t r i b u t e s s o m e t h i n g an d t h e n t hi e 

ambient air, dust and soil levels also contribute their bit 

so none of them is totally dominant. 

If you have several contributions to blood-lead, 

then you would be running into variations from one individual 

to another even with almost exactly the same exposure, almost 

the same location: be running into typical, variations in 

blood-lead which would be plus or minus 40 percent for GSTs 

of 1.42 sc aled back. 

35, 40 percent would be a typical kind of 

proportionate variability. This is because there is a 

diversity of sources. 

You have biological variability. People differ in 

the amount that they can absorb through the duct, through 

the lungs, where they have a higher ventilation rate. There 

are lots of differences from one individual to another, 

biological differences, then differences in exposure. 

Some people eat more dirt than other people and 

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i i j. . i....... . _.. p-.. 

•:-J. 1 -p. '.- •' I ':•;' •*_•? p- r •._ L ' - 1 I *-• f 

V I- 1 

levels . 

1 'DW 1 eve l B „ 

v a v i abi111v • 

bute to that variability 

;ypical measure of variability seems to be 

down to fairly low 

ieve is something that does not seem to shrink at 

As mentioned, that is the analytical 

You cannot knock that down lower than a couple of 

micrograms per deciliter. 

CHAIRMAN LARSON: That is a constant on top of 

things that are continually shrinking. 

DR. MARCUS: There have not been any efforts made 

in this incident to correct these GSDs for the variations in 

the analytical variability because any standards that are set 

are going to have to take the fact that this is a built-in 

measurement. 

Compliance tests have that analytical variability 

built in. So we did not make any adjustments for analytical 

variability in these calculations. 

DR. MUSHAK: But the early NHANES analyses did. 

MR. COHEN: Yes. I guess the decision was not to 

take that into account because of all the health studies they 

were going to be relating to. 

CHAIRMAN LARSON: If we are uncertain, 

collectively or individually, about what the geometric 

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'-yrj...,-.^ 

"fc.Sptfpi.- . 

y^ki't. 

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c : i i I!.. • V .p. . I ( i 

ite v 

standard deviations would do around these site:- ir 

the source, is there any sense of if they would be g\ 

less than they currently are? 

'Or can we not say that? 

DR. RABINOWITZ: We could just venture a guess. 

I get the sense that contained within this lognormal distribution of blood-leads that we see are really 

many sub-populations. Even if you plot them all together and 

add them up, it all looks like some 1 og -normal straight line?. 

There are really many different populations. By 

changing exposure to, say, airborne lead and leaving these 

other factors constant, many people will decrease their lead 

levels and blood-leads. Everybody will take a step to the 

left, as it were. 

But many people, some s u b-p opu1 at i ons, ar e st i11 

getting lead from some other non-air source. These people 

will not track where the others track. 

You are going to see a broadening of the 

distribution. The magnitude of that broadening? Gee, I 

don't know, but it would be surprised if everybody uniformly 

kept the same variance and decreased the mean. 

Is it possible to think in terms of keeping the 

variance as large as it is and just decreasing the mean as 

one extreme set of possibilities? Then you wind up with 

having some tail, some high-exposure tail which, even though 

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you have zero lead in the air, you are still going to have 

these children getting lead from other sources,. 

DR. MUSHAK: But then we are getting back to this 

paint and non—paint, and rural. We went through that once 

b e 1 o v e. 

Presumably you are going to be fairly well rid of 

paint exposures, or even the idiosyncratic exposure, cultural 

exposure. 

So that should be minimum. 

DR. MARCUS: These are all plausible ways of 

dealing with it, but short of actually looking at a situation 

in which there is going to be a substantial change in 

exposure and looking at children before and after, and 

tracking which ones had their blood-leads drop a lot and 

which ernes did not have their blood-leads drops so much 

becaLise they were not getting it from that kind of exposure 

anyway. 

Short of actually doing these studies where you do 

manipulate the lead exposure in the environment, I don'i 

think we have, quote, the right, end quote, answer to this. 

So the attempt, at least, to estimate the fraction 

of high-lead children by assuming a constant proportional 

variability seemed like a reasonable approach. We are 

certainly agreeable to looking at other alternatives that are 

suqqested. 

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J. -A , -..- ! ! \ we n an uptal 

biokinet : mode.i. whicn pre means, arid then we hav 

a n o t h e r ni o d e 1 w! i i c h pred i c t s t h * 

p o p LI 1 a t i o n tha t s h o i .i 1 ci n •: .' '-• L1

1? '..'o. n f LI s e d w i t h t h e u p t a k e 

b1ok i ntti c m ode1. 

So we could make that distinction. I think it 

would be usefu.l, at least, for people to know that they are 

really two different mos :o rning from two different pj laces. 

MR. COHEN: There was one data set, the NHANES II, 

where we did have the opportunity to play with the shape of 

the distribution. Joel Schwartz looked at different cut-offs 

and moved children down, moving down the mean associated with 

that from 40, let's say, or 30 micrograms per deciliter. 

In other words, he would take all the children 

above 40 and move them down somewhere else?. 

We found that the GSD really did not change 

significantly when he did that. 

DR. RABINOWITZ: How did he move them down? You 

mean down by selecting sub-groups with lower exposure? 

MR. COHEN: He took the sub-groups•with higher 

exposure and tailed them. It really boiled down to the fact 

there just were not that many children up there; but if you 

use 40 as a cut-off, I think the GSD changed from 1.43 to 

1.42. 

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DR. RABINOWITZ; very smal l difference . 

MR. COHEN: Yes . 

I think we talked about doing that kind of thing 

with the East Helena data to see what effect it would have on 

the overall GSD, anticipating that a lot of these children 

would have lower exposures in the future. 

We have-? not done? that, but we could. 

DR. RABINOWITZ: Are you satisfied with the 

biokinetic modeling that the variability that you see with 

all these different terms finds its way into the? end of the 

model? 

This model is used to generate distribution at the 

end and it is based on certain of these variables. Each of 

these variables has uncertainties associated with it. 

When you put them all together in the model, all 

these Lincertainties should add or compound in some way. I 

don't know if you feel that that is being taken into account. 

DR. MARCUS: What you could do in the extremely 

ideal universe is take all these 20 or so input parameters, 

convene a panel of experts to tell you what the distribution 

of parameters is in the biological or exposure population, 

and do humongous simulation with a distribution of every one 

of those parameters. 

This would give you some way of propogating the 

uncertainties through the model. This is not a feasible 

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p ro g r a m r i gh t a t t h e mome n t , I thi n k 

W e ! i a v e d o r 

L- 11'.:? U ;::l r 'i d I'l i !••:' t lr? C • !--. ;-. + 

Jone sensitivit y analyse s wit h a coupl e o f 

l CT :• V^irl e •>. prior i , thoi..iqht t o be th e n*ioss*t 

sen s i t ive, i n c 1 u d i. n g t h e a b s o r p t i o n v a t e s, w h i c h h ad a c t LI ally 

some ompivical support. We are going to look at the Last 

Heiena. 

But short of a systematic exploration of the 

sensitivity of the model to plausible distributions over all 

those inputs, in many cases we would be dealing with an 

almost non-existent empirical data base to do that. 

Yes, I would like to be able to do that and then 

say, "If you propogate all these uncertainties through, here 

is the real uncertainty"; but it looks like a lot of work 

right now. 

I suspect we would end up creating a version of 

the central limit there which says that if you add up a bunch 

of things, it turns out to be about normally distributed. 

Here we are going to end up with sort of multiplicative 

factors because uncertainty in absorption rate multiplies to 

uncertainty in the amount of dirt that is eaten which 

multiplies into something else and you will end up with a 

log-normal distribution, pretty near, because of the large 

number of things that multiply each other. 

Yes, it is possible; but I don't think that we are 

going to have grossly different results even if we could 

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carry out that program arid if we? knew what kinds ov 

uncertainties in some of these input parameters we would be 

dealing with. 

'DR. RABINOWITZ: My concern, maybe echoing Dr„ 

Marcus said, was that when you are all done? you don't want to 

have too much faith that your answer is finally right;: that 

somehow you have to have ail the caveats and the 

uncertainties in the fina 1 resu11s. 

I don't know how you do that carefully. 

DR. MARCUS: I think our concevn is particular 

with those who are most highly at risk; and that we are not 

going to be greatly underestimating the high-risk subpopulation. 

That is why we are .tending towards the use of a 

larger GSD than in some studies. 

DR. MUSHAK: Yes. 

MR. HAINES: The other point I wanted to make is 

our purpose of the model is to look at relative differences 

between alternative strategies eventually. I am. trying to 

say we could be off in the absolute number, but if we show 

the deltas between standard A and standard B, even though we 

may be low in both cases or too high in both cases, it is the 

relative additional protection one alternative has over 

another that is what we are seeking. 

I feel that the model behaves itself reasonably 

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well. We may be n o t c • u i t e f i n ding p v o o f :i n o u r p r e cl i c t i v e 

power, but if we can get a reasonable benchmark and help the 

dec i si on-maker decide between two alternative's, we may be 

somewhere. 

DR. RABINOWITZ: As long as people don't, then, 

use it for something else, it will be all right., That is a 

has av d. 

MR. HAINES: We w ill wor r y ab out m i s—ap p1i cat i on 

o f mode1s 1 ater. 

[Laughter] 

DR. von LINDERN: I can tell you what our 

experience has been back in the days when it really used to 

rain lead in our community and our blood-lead levels were 20, 

30, 40, SO, 100 and above. 

We saw that standard deviation collapse somewhere 

down toward 1.3. I think that is probably reflective of a 

biological and analytical variance. 

Nowadays we see it pushed beyond 1.42 and it is up 

about 1.5 now. I think that is because we are dealing with 

more than one pathway or exposure route. 

When you have two or three exposure routes that 

are competing, that adds to that variance. 

I would expect, as we get toward lower blood-lead 

levels when different routes can have more equal influence, 

you are going to have to go to a larger, number. 

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[Jr. ., 

a r e g ue s s i n q , s I J. q h 11 y 

,Ju'•..t 1 o c ar r y t h i s guess, si nc e we 

ther, wkien you are qoinq to 

pathways where there is not such a clear domination of one 

over another, you may have s.TMime veal differences in the bioavailability o f the different sources,. 

Some of what we see as a fairly increase in intake 

0 f b 1 ood--lead- I am t h i n k i ng o v t he st udies wi t h t he i n f ant s 

where there was water Lised for making infant formula and it 

1 o ok e d 1 i k e t h e? r e w a s a f a i r 1 y r a p i d i n c r e ase in b 1 o o d -1 e a d — 

that may be £ige, it may be a difference in previous body 

stories of lead. It could be a lot of things. 

It could be bio-availability. 

I think with blood-leads other circumstances 

applying standard deviations obtained from other data sets is 

something that is chancy to do. In a way it is supporting 

what Ian and Mike have been saying. 

I am not sure I am expressing it clearly. 

CHAIRMAN LARSON: Would you be more comfortable 

with a range of GSDs? 

If you leave them without the option of Model 2, 

which is this GSD application to the mean, then they are back 

to square zero in terms of predicting the levels of those 

children. 

DR. von LINDERN: I think it is the way to do it. 

When you see our document, you will see we did it that way, 

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too. 

[Laughter II 

DR. RABINOWITZ: Which was are you referring to 

now? 

DR. von LINDERN: It is, but I am sure everyone 

here is aware that that becomes a very, very sensitive 

parameter, though, when you are talking about the percentage 

of children that exceed the blood-lead level and we are 

talking about protecting in the 2, 3, 5 percent level or 

whatever they select. 

That is an important value. I think we should 

recognize that. 

DR. MARCUS: Maybe I should address this to the 

Committee as a whole. 

Would you, then, to compare the sensitivity of 

these estimates to a population with more variability to see 

whether or not that makes a difference? 

DR. von LINDERN: Certainly. I think probably the 

way to express that is in percent exceedances, where we end 

up. 

DR. MARCUS: Okay. 

DR. von LINDERN: The question is what are the 

blood-lead values; but that is not here to be decided. 

CHAIRMAN LARSON: I guess we are saying that that 

is an important parameter. It should not be defended, if you 

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L

 -r » l-rpp.- u U i e .i uptak e biokineti c approach . 

oul d be defended, , bu t i t i s i v i c> LI s x y a ver y 

sensitiv e paramete r i n th e whol e resi.il t . 

Ar e ther e any other* commeints 'irom th e Lorn mi 11 et? 

mefVioev s 

[No v espijiise. ] 

We can now hea r from you fello w abou t tri e cas e 

s l- Li U .L e 

MR. COHEN: Okay . 

Before we leave this, before the break Ian talked 

a b o u t t y p i c a 1 s o i 1 i n g e s t i o n rate s that t h e? y der i v e? d in 

Bunker Hi 11. 

I guess one thing that we should note in that 

population is there was a long history of severe lead 

poisoning problems. There was a lot of publicity and a very 

aggressive intervention program that may have resulted in a 

higher consciousness about sanitaryn habits on the part of 

parents. 

I tend to not use the typical Bunker Hill child as 

compared to the quote/unquote high-risk case for 

extrapolating from the model to the places and not presume 

that these other places would have the same kinds of 

education or public health awareness. 

CHAIRMAN LARSON: Is this getting back to the 

issue of how many milligrams of dirt we eat per day? 

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Mr7> !~*o \..$ LTr j • rr* -j .-; i-,j.• 

CHAIRMAN LARSON: It seems 

few i"iumbers ge11 i nq passed ar ••::>urid . 

DR. MUSHAK: This business 

parental a p p r e h e n s :i. o n i n d r i v i n g d o w n A , i: l.i 1111..' ir; r 

know c>f a case—i t has not been written Lip in any formal 

way in eastern Pennsylvania where after there ha cri beer*, a lot 

of community publicity the parents literally chased the 

c h i 1 d r e? n i n t o t h e i r o VJ n hi o u s e s. 

It was that kind of culture to begin with: bluecollar, very stringent attention on kids. Those kids were 

literally harassed. 

Some of the psychological problems may be-? worse 

than the problem. 

[Laughter] 

The fact remaining is I think once you have a 

pervasive community awareness, parentally, of the problems in 

that issue you are going to turn up with less and less of a 

problem. We can see it anecdotally in the Bunker Hill 

situation. 

So it may not be appropriate. In other words, the 

ideal case is if there were no awareness and everybody was 

doing the same old thing, what would be the average? 

DR. von LINDERN: For those who want to punish 

yourselves, this is the report. It was just sent out Friday. 

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.}• 

I am sure? tnere are copies- available < or wnoever wua,i u 

to- vevi ew it. 

It is a proposal and it is subject to change based 

on all the comments that come in over the next month; but, on 

Jeff's point, the position that hi as been laid out at this 

time is that we expect those values are depressed as a resi.il t 

•::if years of attention being paid to this problem up there. 

I think that is particularly true with the typical 

child, perhaps not so true with the high-risk child. Maybe 

one? of the? reasons why it is a high-risk child is because it 

has not worked with the high-risk child. 

So the recommendation at this point is to use. 100 

milligrams per day to represent a two-year-old, and it is 

based on the recommendation of— I cannot remember out of 

which office of Environmental Protection Agency it came—a 

symposium on soil ingestion rates. 

DR. MARCUS: I believe that was the Exposure 

Assessment Group. I am not real sure. 

DR. von LINDERN: At this point, we think the 100 

milligrams per day is appropriate. We don't see any reason, 

at least in our data, to use any other number: 

CHAIRMAN LARSON: And you apply a GSD on that mean 

prediction? 

MR. COHEN: Around that, that's right: around the 

end result. 

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•iRSON: I am somewhat confused by the 

not :i ori o f a hi i oh — r :l sk per son versus the avevage pet* son . 

DR. von LINDERN: I hope I anticipate this answer. 

Yoi.1 c:annot th:i. nI -: of a hi gh-• r i sk chi 1 d i n the 

Bunker Hill situation in terms of plus-two standard 

deviations, that type of thing. There is a fairly 

substantial percentage of our children who are at high risk 

because they are living in an environment at a high 

cr onc en t r at i on . 

That does not apply that, statistically, it is a 

plus or minus standard two deviation type of thing. It is a 

profile that we use. 

I don't know what the exact percentage is, but it 

i s q u i t e a b i t hi i g h e r t h a n t h a t. 

CHAIRMAN LARSON: Would that type of information 

be available for these other places where you are planning to 

this extrapolation sort of thing? 

MR. COHEN: Not that I know of. 

MR. HAINES: East Helena is probably the only 

other data set. 

MR. COHEN: And East Helena was the study location 

for the Binder and all study action, the source of our 

estimate. 

DR. RABINOWITZ: Are you in touch with Chuck 

Gilbert? 

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MR. COHEN: Yes. 

DR. RABINOWITZ: He had numbers, 

MR. COHEN: I have not talked to him in three 

m o n t l"i s, b LI t I ki a v e bee n k e e p i n g in t o u c h w i t h P a u 1 W h i t e w kt c • 

is also doing a similar study out in Washington State. We 

a.re anticipating those results. 

Hopefully we will be able to incorporate? those 

i r11 CJ ci u r fin a 1 s e t o f p a r a m e? t e r s. 

CHAIRMAN LARSON: Okay, Jeff. 

MR. COHEN: In our handouts, it is the-? second 

table. 

DR. von LINDERN: I have that reference if you are 

interested in it: Cc'IIoguiem o_f CK.i and Dermal Exgosure to 

Soil, and Dustji_ RisliZiSSSEl^ffiSDt E2HQ}- That was ORD, March. 

MR. COHEN: March 1988? 

CASE STUDY RESULTS AND DISCUSSION 

MR. COHEN: I am going to show you some 

preliminary results actually running this model, where we 

have been debating about this model. These are in 

populations of children living near East Helena and a 

secondary population in Dallas. 

We looked at various alternative scenarios, 

including a quarterly average standard, which is equivalent 

to the current level, 1.5, and then five alternative monthly 

average standards between .5 and 1.5. 

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We also estimated children's blood-le;ad with the 

aggregate model and adults' using the disaggregate approach, 

as described in the report. This is obviously taken up iri 

the recommendations we have been hearing today. 

Again, we have assumed two alternative soi1-1ead 

scenarios: one where soil—lead is maintained at baseline 

1 eve 1 s re?gard 1 ess of what air-lead changes occurred after 

1990; and the other alternative is assuming that, for 

whatever reason, soil-lead does respond instantaneously. 

We were uncertain what the right call is there. 

We just wanted to balance what might be plausible. 

DR. RABINOWITZ: Baseline. You don't mean 

bac kground. 

MR. COHEN: Baseline air quality as it exists 

today. 

DR. RABINOWITZ: Okay. 

MR. COHEN: This is Scenario 2, which we feel is 

the more plausible scenario, keeping soil at constant over 

the new few years. Dallas and East Helena are listed: 241 

children in Dallas, 217 in East Helena. 

Mean blood-leads are shown for the*different 

scenarios and using the GSD of 1.42 we calculated percentages 

above selected blood-leads. They are just shown as examples. 

The 25 is, I think, still currently CBC's 

definition of toxicity. It probably will change in the near 

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+• ,.,.; i i 

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DR. MARCUS: The betting i < 

MR. COHEN: Right. 

DR. von LINDERN; What is your soil assumption 

t her e? 

MR. COHEN: The soil assumption is that it is s 

at whatever air quality is in 1990, except for the basslin 

case, In other air-lead has been fairly constant over 

the previous years and the soi 1—1 ead is estimated base?d on 

that a i r q LI a 1 i t y. 

After the new standard is set, it remains fixed. 

DR. von LINDERN: So it came from that formula you 

discussed before? 

MR. COHEN: Yes. That is an equilibrated soil, 

and based on that progression model. 

Just to read across the top line to give you an 

idea of what is going on, for the; 19.33 baseline in Dallas we 

have a mean blood-lead of 7.5. 20 percent or so of the 

children would be about 10 and 2.3 percent would be about 15 

and .03 above 25. 

DR. MUSHAK: That is for certain air-leads and 

certian soil-leads. 

MR. COHEN: Yes. It is actually a certain airlead standard and the associated air-qLiality impacts around 

the source given that standard. 

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DR. v CJ n LIN D E R N: D o y o u k n o w what t h a t n u n i b e r i s 

of the lead equilibrated? 

MR. COHEN; We estimate air quality at the highest 

receptor point, dust at that standard, whatever standard that 

we? are looking at. 

DR. von LINDERN: So when we are looking at 1.5, 

we are saying 1.5 is the maximum receptor point. 

MR. COHEN: Then the air quality would be 

dispersed in the model around that. Soi 1-1 ead would be? 

predicted for each receptor point and spread out on a blockby-block basis in this case based on the regression model of 

the equilibrated soil air-lead relationships. 

I don't have it here, but I was going to show you 

the results that we got from the aggregate model for 

children. That is where we use the air/blood/soi1-level 

slope similar to what was done in 1973. 

I think it is in the hand-out. It is a plot of 

the results looking at only percentages above 10 micrograms 

per decimeter. You can see the sensitivity of the results 

and see what soil scenario you look at. 

Scenario 1, again, is assuming that air-lead 

produces an instantaneous change in soi1-1ead levels. You 

can also see that there are some differences between 

locations: Dallas, in one scenario having lower blood-leads; 

in the other slightly higher for the lower standards. 

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O ff th e graph woul d be baselin e percentages , whi ; 

ar e pr-' Ci O '/SI ti n I think I do have a plot of the 

cir the ag q r eg at e aiocie 1 , ob v i ous 1 y on on e sc en ar i o 

. j u s t 1 CJ P::> k i n g a t t h e a i r -1 e a d / b 1 o o d -le a c:l r e 3. a t i o n s I j i p d :i. r e c 11 y 

without going t hr ough soi 1 ••-lead assumpt i ons. 

DR. vein LINDERN: There is a difference in that 

because of the geographic lay-out of the area? 

MR. COHEN: Yes, and because of the air-quality 

i mpac ts. 

DF?. von LINDERN: The modeling impacts where the 

receptors are? 

DR. McLAMB: And the distribution of people. 

MF?. HAINES: How close they are to the site. 

DR. McLAMB: Exactly. Are they coincident with 

the high receptor values for the modeling exercise? 

MR. COHEN: We have done the same kinds of things 

for middle-age men, in this case whites, using the 

disaggregate model. Again, you could see the mean bloodleads, percentages above various selected cut-offs. 

In this case, we went down to 8, 10 at 15. In 

Dallas, for example, we predict 18-1/2 percent would be above 

8, 5.4 percent would be above 10 in 1988 baseline. 

From what we heard today, I think we need to reexamine the methodology we use to,estimate blood-leads for 

women; but using what is described in the report as it stands 

. ) • 

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improvemen 

mean: not 

now, we have some results for them, too. 

Again, you can see the small incremental 

as you go to lower and I owe 

sensitive as children are at the higher end. 

Once we arrive at case study results that we? a.r< 

comfortable with, we would like to incorporate them into tl 

draft staff paper in early .1989. The staff paper will 

contain recommendations on alternative standards. 

"he focus will be b 1 • •lead 1 c-? v e 1 s o f c o n >:: e r n 

based on the criteria document assessment, whatever updated 

assessment that ECAO will wind up doing. We will also have? 

recommendations on the aggregate time of the standard, 

mon it oring frequency. 

Case study results will also be incorporated into 

tFie benefits analysis. That methodology was reviewed by a 

subcommittee last year. Those results will be incorporated 

into the overall regulatory impact analyses. 

Dave McLamb will talk about this by the end of the 

day. 

That is all I wanted to sFiow you for now. 

DR. RABINOWITZ: On the hand-outs, on page 44 

where we have the results of the disaggregate model for women 

of child-bearing age, there is an asterisk and it refers to 

children. 

That is the end of it? 

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MR. COHEN: Ni 

DR. RABINOW1 Maybe that is from a different 

MR. COHEN: Yes. 

DR. RABINOWITZ; Okay. 

MR. COHEN: It should read "Women, 15 to 44 years 

•'.j r <•.•*. u &. 

DR. MUSHAK: What do those refer to? 

MR. COHEN: The actual number of people? that were 

within those areas. That is based on Census data. 

DR. MUSHAK: - So we are talking about 20 people? 

MR. COHEN: 20 women in that age group: a really 

small population, a lot more children. 

DR. MUSHAK: This is the City of Dallas? 

MR. COHEN: Yes. 

DR. MUSHAK: Intuitively, that seems like a low 

number. I don't know. 

MR. COHEN: 3 kilometers. 

DR. MUSHAK: Still, 20 pregnant women in 3 

kilometers in a big city— 

DR. RABINOWITZ: So for each of these 20 women, 

there is a certain air-lead, a certain soil-lead and then 

they do the mathematics? 

MR. COHEN: Yes. 

DR. RABINOWITZ: They get a distribution for each 

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analysis is part of the lead NAAQS review. 

Dave will give you some bac kgr ou.rid. 

ULJ. Dj?l'id W_j. McLamb 

DF?. McLAMB: The reason we have been making a big 

point about this last item is because it is tied to the lead 

NAAQS. There are at least three people on this Subcommittee 

who reviewed the benefit analysis. 

I just want to remind those guys: we are using the 

outputs of the blood-lead modeling exercise we have seen 

t od a y t o g e n e r a t e t h e b e n e f i t e? s t i m a t e s. 

A littl e mor e background . 

A primar y motivatio n for doin g tFie benefi t 

estimate s at least starte d in th e Environmenta l Protectio n 

Agency from Executive Order 12-291 which requires us to do 

benefit and cost estimates for alternative standards we 

consider. 

Hence, we have, in the past, gotten some pe?er 

review on how we might go about doing benefits. 

Equally important, we want to make sure it is 

fairly consistent with the scientific literature as it is 

graded, if you will, by CASAC. 

Basically, our benefit analysis for lead focuses 

on three different health end points, the first being on the 

chart up here: elevations in erythrocyte, protoporphin and 

blood-lead. 

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Ci f t h ci s e 2 0 w o men a n d t h a t i s w h a t i s s h o w n I-1 e r c? ? 

MR. COHEN; Yes . 

DR. RABINOWITZ; So of the 20, there will be 

different a i r -1 e a d is, ci i f fere n t s o i 1 -1 e a ci s cj e p e n ci i n g o n — 

MR. COHEN: Depending on what block they live on. 

DR. RABINOWITZ; Okay. 

CHAIRMAN LARSON; You mentioned that you had 

predictions based on where people? 1 i veci rel at ive to the' 

impact of air quality. 

DR. McLAMB: Precisely, we look at the Census 

data, the most detailed data that we can get when we apply 

this to other places to see the impact of alternative 

standards. 

We pretend that it is like a geographic weighted 

average of where people are located within a Census tract. 

We use an ISC model to predict ambient concentrations under 

alternative standards. 

If there are people that are block-group-centroid 

for one receptor, then they will get whatever concentration 

the model predicted for that receptor. Typically, we find 

several block-group-centroids within so many kilometers of 

these sources. 

We will have end groups of people with the same 

ambient concentration which, depending on the scenario we 

look at, will dictate the soil and dust levels. 

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Does that answer your que?stion? 

MR. HAINES: We come up with a mean and then we 

predict the GSD from the mean. 

D R. M c L A lvl B: Y e s. 

CHAIRMAN LARSON: You have a variance predicted by 

the model which you use? to just collectively use that 

info r mat i on t o c omp u t e a m ean. 

DR. McLAMB: That is correct. 

C H AIRMAN LARS0N: Th en you predict a differ ent 

v a r i o us f r om t he sec ond step. 

DR. McLAMB: The second variance is given that we 

discuss earlier here. 

CHAIRMAN LARSON: We don't feel that the variance 

predicted by the model is going to capture all the variables. 

We are fortunate that we have data on this 

measurement. 

MR. COHEN: Are there any other questions on that? 

[No response.] 

Okay. Do we want to go to the next phase? 

CHAIRMAN LARSON: I think it would be useful to 

keep going here, if possible. Page 48. 

MR. COHEN: We have been talking about other 

applications of these methodologies. There are a lot of 

analyses within the agency and outside relating to lead. 

Naturally there has been a lot of interest in what 

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131 

has been going on in developing these models. We thought it 

would be useful to get some feedback from the Subcommittee on 

the potential usefulness of extrapolating these methodologies 

t CJ ci t ki e v' s i t u a t i o n s, 

Again, I don't have the slide but it is in your 

hand-out. There are a couple of other applications that have 

been ident ifi ed. 

For example, we talk about Super Fund sites, leadcontaminated-soi1 problems. The Office of Drinking Water was 

interested in how to assess high-level peak intermittent 

exposures from school drinking fountains, for example. 

They thought the biokinetic model was an 

appropriate tool to measure the rapid changes associated with 

that. Land application of sewage sludge is another potential 

i n t erest ed assessment. 

Similarly, municipal waste incinerators produce 

some lead from the stacks. There might be some relevance for 

some of these models. It may not be the biokinetic model, it 

may be the aggregate model. 

Relative ranking of different pollutants based on 

daily intake estimates. A lot of risk assessments in the 

Environmental Protection Agency are based on average daily or 

acceptable daily intake, and the uptake model produces those 

kinds of estimates for lead. 

The benefits analysis for the regulator impact 

EXECUTIVE COURT REPORTERS (301) 565-0064 
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Basicall y CD C ha s designe d protocol s whic h define? 

h o w and whe n childre n are treate d for lead toxicit y base d on 

t h e s e t w o p a r a m e t e r v a 1 u e? s. 

In our benefit s analysis , w e basically , for 

alternat i v e? s t a n d a r d s, 1 o o k e? d a t h o w c o s t s o f s c r e e n i n g a n d 

treatment vary as you 1 owe?r ambient exposure to lead. 

The s e c ond b e n e f i t c a t e? g o r y w e? 1 o o 1 ••: a t i s 

intelligent quotient, or IQ decrements. As you reduce any 

kind of lead exposure—in our case ambient lead—there are a 

number of studies that show that IQ, at least the average IQ, 

will change for large groups of children. 

In our valuation methodology, we basically look at 

how the productivity of society changes as IQ improves 

marginally, and we measure that by looking at basically 

changes in expected lifetime earnings and stuff like that. 

There is a second sub-category of this IQ stuff. 

That has to do with cost of treating children who are 

severely retarded. 

If you change ambient lead by some amount, you 

will change blood-lead exposure which gives you the marginal 

change in IQ, which again shifts the distribution: there will 

be slightly fewer children designated as being severely 

retarded and they will get less remedial education and 

treatment. 

The third benefit category we have been able to 

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134 

evaluate? has to do with elevations in blood pressure?: quite a 

controversial category, I think, over the past few years. At 

least to date, we? still plan to pursue? that, only for adult 

m ales, t hou g h, I wou1d 1i ke t o men t ion. 

Basi c a 1 1 y F*ier e, when we? est i mat e be?ne f i t s, we 1 ook 

at the reductions in the costs of treating hypertensive 

males. 

Sec on d 1 y, we 1 oo k at t h e reduced c ost o f t r eat i n g 

cardiovascular and cerebral-vascular consequences of elevate?d 

b1ood pressure. 

I would like to make several comments in regard to 

qualification of the limitations and the benefits we have 

been able to estimate. 

We know there are a lot of other significant 

health effects that, at least currently, we don't feel we can 

quantify. Furthermore, the benefit categories we are 

estimating benefits for are for those categories we felt 

comfortable identifying as of early 1987. 

As far as we are concerned, the jury is out right 

now as to whether or not we can expand our benefit analysis 

any at al1. We will wait to see what happens in the next 

full CASAC meeting. 

It is my understanding there are quite a few 

studi es st i11 out. 

In March 1987, we convened a Subcommittee very 

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rnuc h 1 i k e t h i s one. There? were at?out t wo ad d i t i on a 1 

economists on it as well as members from the Health 

Committee, from the full CASAC. 

W e a !:•:• I ••: e cl for c o rn m e n t s. W e r e s p o n d e d t CJ t h £-? 

comments at tkie meeting. We got closure letter from both 

Mcir t Li ppman , co-si gned by Bob P.owe who was the Subcommi ttee 

co-chairman, back in June .1937 I believe. 

W e ha v e i nc or p or at ed t h ose c omments i n t o t he 

document with the exception of some comments I believe we got 

from either Dr. Mahaffey or Dr. Chisolm who said that our EP 

blooci-lead relationships should be disaggregated by ARN 

status. 

We are currently modifying those physical effects 

functions that give us those benefit categories. Allan • 

Marcus has been working with us on tFiat. 

So we pretty much incorporate all the benefits we 

got except for the final change. 

We have yet to do any benefit estimation for these 

preliminary blood-lead numbers you have seen today because 

they were just available a couple of weeks ago. Again, we 

have not finished up the blood-lead EPA stuff on ARN status. 

Just to give you an idea how all this fits into 

the RIA, you will see a little block. On the top, it says 

"blood-lead exposure". That is what we have been talking 

about today. 

EXECUTIVE COURT REPORTERS (301) 565-0064 
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In the RIA, there are a number of analyses going 

on and they feed into one artii'ther in various ways,. Therir. are 

really other links that kind of feed on one another in a 

g e n e r a 1 e q Li i 1 i b r i u m s e n s e, b u t I d o n ' t w a n t t o c: 1 o u d t h e 

discussion with that. 

In any event, the top row describes our benefit 

estimates. We look at base?line ambient concentrations and, 

using dispersion modelings, we-? estimate? ambient baseline 

concentrations. The?n we see how we add controls and how lead 

concentrations will change as we add controls to our ambient 

impacts measure, which again drives blood-lead as we have? 

seen today. 

Changes in blood-lead will yield changes in health 

effects, and the health effects are valued as I just 

described. 

At the same time, the ambient impacts are driving 

blood-lead exposure all the way down to benefits. We are 

estimating engineering costs as we add controls. 

Then through a lot of simple-minded economic 

models, we estimate social costs. You put the benefits and 

the costs together and you come up with a benefit/cost 

analysis pretty much as the mandate in Executive Order 12-

291. 

That concludes my presentation. 

DR. MUSHAK: Let me understand. 

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The Clean Air Act says you will not 

DR. McLAMB: Absolutely. 

DR. MUSHAK: But you do this anyway. 

DR. McLAMB: Well, the President told us to. 

[Laughter] 

DR. MUSHAK: Ok: ay. 

DR. RABINOWITZ: So you sort of closed in terms of 

health effects you want to consider for the purposes of this 

cost/benefit analysis? 

DR. McLAMB: We are closed to date until the full 

CASAC convenes again and looks at the new literature. I 

believe we can quantify fetal effects, for instance. 

So right now it is fixed in time, but we pretty 

much have to take the lead until tfte scientific community 

comes to some sort of general agreement tFiat we can actually 

value on. 

MR. HAINES: Isn't it true there are other 

effects identified in the literature that are well-accepted 

within the scientific community that you have problems 

evaluating? 

DR. McLAMB: And there are some non-effects on 

which we don't have the physical functions, also: a subcategory of the ones we cannot quantify. 

MR. HAINES: So it is an interactive type. Before 

he can come up with benefits, there are several conditions 

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P.40 

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)Sr 

that hav 

DR. RABINOWITZi So you don't wan 

that reported some'th i nq. You want some? kind 

that this is a s i m ila r phen omenon ? 

MR. COHEN; No. We need to make the distinction 

i B *£• o n e pape v 

consensus 

:lear between the benef i t s a rtalysi - -"- "• s arid the health-risk 

assessment that goes to the staff. We recommend a blood-lead 

level of concern will incorporate health effects whether or 

not they c a n b e? m o n e t i :•: e? d . 

We are not ignoring those other health effects in 

setting the standard. In doing the benefits analysis, we 

have to draw the line that those effects that can be 

quantified in monetary terms. 

MR. HAINES: That is the point I was trying to 

make. 

David has two conditions on what does the science 

say about a health effect. We are going to use the total 

date set, a portion of which he may not be able to monetize 

and come with a monetary value on. 

DR. McLAMB: A good example is what is the value 

of improving forced expiratory volume? We had a tough time, 

as an economist, evaluating those kinds of health effects, at 

least to date. 

CHAIRMAN LARSON: Prior to some discussion among 

us here, I wanted to turn it over briefly to Bob for some 

EXECUTIVE COURT REPORTERS (301) 565-0064 
P.41 

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additiona l comments on th e proces s we ar e involve d wit h here . 

Ai. Pwber_t E-LsL*A!< 

MR. FLAAK: Before the Subcommittee gets into its 

filial wrap-up today and some of the general consensus points 

t ki a t t h e 3 u b c o m m i 11 e e w a n t s t o b r i n g t o t h e C o m fti i. 11 e e' Spat te n tio n get gelle d an d finalized , I wante d t o tal k a littlebit about the process whereby the Committee operations; and 

here I say the full CASAC, the seven-member Committee. 

For those individuals who aire new to the CASAC 

process—Paul and Scott and Ian—this is primarily for you so 

you have an understanding of how we do business. For the 

rest of you who have been involved in this before, it is a 

rearrangement of something you probably know a little bit 

aboui t. 

This is a Subcommittee of CASAC. As such, its 

recommendations pass through the full Committee. 

CASAC is the only Committee within the Science 

Advisory Board whose recommendations go directly to the 

Administrator without passing through the Science Advisory 

Board's Executive Committee or Steering Committee. 

That is because CASAC is mandated as a separate 

committee by separate legislation and is merely housed within 

the Science Advisory Board for administrative purposes. 

As far as a Subcommittee is concerned—and all of 

our subcommittees are chaired by either a member of the full 

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CASAC or by another member of the Science Advisory Be i <-.i r I.J 

..p.. . -p .; i ... J . whatever OBJ. I oev dns arid result s come out his meet inq 

today will be put in some kind of a concise, clear, to-.-thepoint written form by Tim and I, at some point in the next 

couple weeks*, after this meeting, and forwarded around to the 

other membevs of the Subcommittee for concurrence. 

0 n c e? t ki e S u b c o m m i 1 1 e? e m e m b e r s a r e s a t i s f i e d w i t ki 

tkte document, it will be passed on to the full CASAC seven 

members for their final sign-off at that point. 

There will be a lead meeting of the full Committee 

some time in the early part of 1989, perhaps in February or 

so. We don't have a firm date on that yet. 

At that time or perhaps earlier, certainly at that 

meeting, Dr. Larson will make a presentation which will 

summar i ze the di scussi cms her e, essent i al 1 y 1 ayi ng to r e?st 

this document as far as that meeting coming up in February is 

concerned, which is the purpose of having this meeting today. 

There may be an opportunity to present this to the 

full seven-member Committee at an earlier meeting to get a 

sign-off on it or we may do it via the mail, which we often 

do when an issue is particularly controversial. 

There is an ozone meeting scheduled in the middle 

of December, which may be an appropriate time to bring this 

report to the full Committee's attention for a few minutes. 

With that in mind, whatever final comments we have 

> EXECUTIVE COURT REPORTERS (301) 565-0064 
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'. j . a. i 

interests . We will f oId t hem t og ethe r i nt o w 

consensu s positio n of everyone here . 

we i'iclips1 

JThank: you. 

CHAIRMAN LARSON: Prior to my task: to trying to 

summarise—partly verbally here?5 but also hopefully, with 

s o rn e m o r e c o n s i d e r e d t h o u g I i t, I w i. 1 1 w v i t e s c:i m e t hi i n g d o w n , 

pass it around and we will all take a shot, at it—-I would 

1 i k e t o get s o m e s e n s e f r CJ m t hi e S u b c o m m i 11 e e m e m b e r s o n t h e i r 

vi ews on a few of thie quest i ons. 

CHAIRMAN'S SUMMARY 

CHAIRMAN LARSON: First of all, were the comments 

that you submitted and which were addressed earlier today 

address adequately? That is to say, aire you satisfied? 

Given the fact that they might respond in the way that they 

did, do you consider that an adequate addressing of the 

comments that you have heard today? 

Will that be sufficient or are there additional 

comments or issues that were raised today that were not in 

any of those comments that we heard this morning? 

I have made a list here of some of'my own that may 

be addressed directly or indirectly in some of the earlier 

comments. 

Are the modeling approaches reasonably structured? 

That is to say, are we in agreement with the types of 

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exposure models that we have seen, at least in the?.' 

:r uctu r aJ. Tor :D necessar i 3 y th e i ripe 

Can we qet some sens e or 

rc nufiiD&r 

"here seemeci 

a general agreement about the approach of biokinetic uptake 

for the chi1dren and some discussions pro and con about the 

a g g r e g a t e / ci i s a g g r e g a t e m o d e 1 s. 

Kate? 

GENERAL DISCUSSION 

DR. MANAFFEY: I had an easier t i me with t h e 

biokinetic approach recognizing it is missing huge amounts of 

infor mation. 

CHAIRMAN LARSON: I guess that is the second 

question. Given that we are comfortable with that .approach, 

are the avail a.ble data to be used there used appropriately? 

I had a number of points that were possibly at 

least under some discussion: the number of milligrams a day 

eaten by young children; the issues of the constancy of soillead after rapid reduction in air-lead versus some 

correlation between the two. 

My feeling was there was some consensus that we 

should keep that soi 1-1 ead value constant, but* that the dust 

values perhaps are more responsive to the air values. 

The question of smoothing of the data for the 

intermediate-age children, I was not quite sure how we came 

down as a Subcommittee on that issue. 

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•*? of information 

either way. probably the rathe;';" abrupt approach is if you are 

,.-. •!- i. t you ar e 

.-! f ••• r , y c.i u star t 1 o o k i n g 1 i k e a ci u 11 s „ 

DR. CHISOLM: I would guess it would slow down 

from, say, six to ten and then you get in the adolescent 

growth spurt. 

DR. MUSHAK: It could well be. 

DR. CHISOLM: It probably does grow with the 

growth rate. 

MR. COHEN: That is where-? we draw the line, 

really, at six years old. 

13 DR. CHISOLM: Forget the terrible adolescence, 

14 right ? 

15 [Laughter] 

16 CHAIRMAN LARSON: Another issue which was raised: 

17 Given the assumption of a relatively constant lead source, 

18 how do you estimate what that is in the absence of soil 

19 information when you go out and take this model elsewhere? 

20 There was some discussion about the differences in 

21 that steady-state air-1ead/soi1-1ead relationship. Maybe we 

22 can take a look at how the results look. We can vary that 

23 over the range that we were discussing. 

24 DR. von LINDERN: Can I ask a question and get a 

25 littl e bi t of clarificatio n on tha t point ? 

EXECUTIVE COURT REPORTERS (301) 565-0064 
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.y.xx 

i ?-c cine o i cho^e enos Lip hingin g or •tv,e 

p re d i c t :i. o n s o f t ki e a :i. r -qualit y ru o del . I t kt i n k a 1 3. o f i. t 

c co ni e s b a c k: t co t ki a t . 

It seems it could be appropriate to me to go out 

artel evaluate sites where you don't have information to 

evaluate the impact of proposed standards. 

Are we t h i n k i n g in t er ms o f i mp 1 emen t at i on t kt at 

way as; well? When we get to implementation, will we look at 

a. c t u a 1 si o i 1 value s i n t hi e? s e 1 o c a t i o n s ? 

Has anybody given that any thought? 

MR. HAINES: I think this got back to your 

question of the policy call. Our mandate is essentially to 

set an appropriate air quality standard. 

We are estimating taking into account soil/dustlead, food, total lead exposure; but we will be implementing 

an air standard, as the Administrator judges, providing 

protection with an adequate margin of safety. 

Separate and apart, you have the parallel issue of 

what do you do in the soil clean-up. So there is 

clarification in the legislative mandates between our best 

estimates of soi1/dust-lead levels and trying to arrive at an 

appropriate standard, but when it comes around to 

implementation we will be implementing the air aspect of it. 

Super Fund and other people will be making an independent 

determination, to some extent, whether or not that soil needs 

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i .-p cr 

t 'Si b e c i e a n e d ; .t p . 

There is:- not the jointness that your comments 

sugge?st ed at t h i s poi nt . 

Tkiat may be a question we will have to discuss 

OLivselves. It is an interesting thing you have laid out: 

whether or not it should be. 

DR. von LINDERN: Where we are at here is to 

e v a 1 u a t e?— 

MR. HAINES: The air portion. Under the? Clean Air 

Act, that is what we are here about. 

CHAIRMAN LARSON: One of the other inputs, perhaps 

which is mentioned but I did not get a sense of where we were 

with it, is this sort of community exposure issue versus the 

b1ock or site-specific exposuve. 

Is that or is that not something important that is 

import ant j and is it taken into account in your analysis'? 

Ian, yoLi mentioned that earlier. 

DR. von LINDERN: Again, I think that sort of ties 

in to the same thing we just talked about. There are 

situations around these point sources where we know a lot 

more than making a model estimate. 

In most cases, we could probably develop a better 

model; but as I understand it that is not something to do 

here. 

MR. HAINES: I think there are two issues here. 

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. L- r; -I- •!- r, l;p f

 -::H hi | .;, I; i on 

••ei riq J. ri your 

cud our evaluatio n 

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LciS-l i- c. .i. 1 V i inpcpp... I i ! ;Lj Ji-'i . I liLU U •-• a.i. .i. •_• 

Helen a or what you ar e 

e f f e c t ci n e s o u r c e i s cl co m i n a t i n g t !• 

i s i mpac t ed by tha t sou r c: e . 

By the same tc>k&n, when 

East Helena we were 

kids in that. W11 ere we t r ans f er t his to a n urban area, sa y 

Dallas, that source is affecting a relatively small area 

around there?. 

I ciuess I am trying to differentiate is that a 

community in East Helena, which I know better than Silver 

Valley, is probably the whole town in flues need by the smelter 

or at least a good portion of it as opposed to a Dallassituation where it is only a small geographic aresi of the 

city. 

I am not sure if we are far apart on what we are-? 

doing here. I think we are Lising different 'words to say 

basically we should be looked at the zone of influence of 

that stationary source. 

CHAIRMAN LARSON: This gets to the question of 

given that we have a structure that we are comfortable with, 

available data, there was some discussion of various 

uncertainties that need to be looked at in terms of the final 

output, as inputs. 

Are the proposed applications of these approaches 

^.: EXECUTIVE COURT REPORTERS (301) 565-0064 
P.49 

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'asonable'"' That i- ', in this-- case, the bi ok i net i 

uptake model applied to tlie children and perhaps, or perhaps 

not, some disaggregate model applied to the adult's or some? 

set of adults. 

I get a consensus that the application of the 

first model to the children is most appropriate, but I am 

still not quite SLire about what we do with the disaggregate 

model and the pregnant worn pen or not, or whether or not there? 

was some consensus about that. 

It seems certain that there was not much 

information at all on the fetus, and we should probably make 

sure we stay clear of that. 

DR. MUSHAK: I suppose they could have equal 

billing. 

Jeff and I were talking a little bit at lunch 

about using this as a data point for the newborn, at point of 

birth with some assumptions, and using an adult model hybrid 

of this plus what Mike had published to try to come up with 

something for women and do an adjustment for the women's 

lead. 

That is, to an adjustment for the resorption: try 

to be as generous with that as possible. 

After that, there is an option. That is, you are 

not really looking at a quote/unquote in-utero span. You are 

ginning another data point that is not available, and it is 

EXECUTIVE COURT REPORTERS (301) 565-0064 
P.50 

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'cnax; we sur 

CHAIRMAN LARS0!'••!: I t h i n k: we c: an c: e?r t a i n 1 y expr ess 

ire important groups to con si cier, and 

'ish we had more data than we do to be able to 

perhaps do it better. 

DR. MAHAFFEY: I find this hard to really say what 

to do with. I don't think anybody wants to create a 

s i. t uati on where-? i. t 1 ooI•: s as t h oug h 1 ook i ng at pr egn ant women 

and the fetus;- is not something to do be?cause-?, in terms of the 

health research, that is a group that is extremely important 

to consi der. 

The other side of it becomes: How do you do this 

a n d do it w i t h s o ro e d e? g r e? e? o f s e? n s e i n the p r o cess ? 

We are kind of hard put to come up with an answer. 

It sounds as though if there is something in Yugoslavian data 

where you can get some blood-leads over time during 

pregnancy, you might have some information to work with. 

There is always a temptation to say, "Sure, go 

ahead and make this model, see how it looks." ' The difficulty 

is after we have done that, we sit and say, "Well, we are 

glad you did that. It was a good thing to do." 

We have this model now. There is always a chance 

someone will pick it up with a few more sets of assumptions 

EXECUTIVE COURT REPORTERS (301) 565-0064 
P.51 

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in it. 

I keep wondering what are we creating in the-? 

process of doing this. 

DR. MUSHAK: That would be the inherent risk with 

the Environmental Protection Agency running arnuk with the 

g e n e? r i c r e a 1 i z a t i o r i. 

MR. HAINES: Realistically, this brings me back to 

t h e? q u e s t i o n I p o s e? d b e f o r e. 

If, in the collectively judgment of the 

Subcommittee, we don't think we are in a position to 

appropriately model and assess this risk in a quantitative 

way, because we don't have the tools and don't have the 

data — 

I want to make sure we don't go down a pathway and 

do something that nobody has any confidence in because of the 

absence of data. If that is the case, maybe we ought to so 

state and say, "We are not in a position to estimate these 

exposures at this point in time. This is the research that 

will have to be carried out over the next several years so we 

can answer that question." 

What I am trying to avoid is we could take the 

approach laid out in the paper,—you know, the alternates— 

put in that caveat, indicate they were developed for adult 

males, have applicability to pregnant females. That is up in 

the air. 

EXECUTIVE COURT REPORTERS (301) 565-0064 
1 We know ver y littl e about th e biokinetic s takin g 

2 place, but we will produce an answer. 

3 What I guess I am saying is that if, in the wisdom 

4 of people? here, if that answer is not worth the paper it is 

5 writte n on , why tak e th e tim e to produc e it ? 

6 CHAIRMA N LARSON : We simpl y are not tellin g yo u t o 

7 c o m p 1 e t e 1 y i g n o r e t h e s u b j e c t b e c a u s e w e f e e? 1 it i s a n 

8 important target group. While it is an important target 

9 group , ther e ar e other way s we talk abou t it in a qualitative? 

10 sense; but we cannot predict what is happening in the future 

11 on this. 

12 DR. MAHAFFEY : It is my experienc e wit h caveat s 

13 that thi s is lik e doin g table?s and somebod y pick s out a 

14 couple of numbers and says, "Yes, this is what you said." 

15 It is a very important group, but in terms of the 

16 biokinetics , unles s ther e is a lot mor e in thi s Yugoslavia n 

17 data than perhaps others have been aware of, I think we out 

18 wher e we don't want t o mak e hig h th e hous e of cards . 

19 MR. HAINES: The bottom line, as I interpret it, 

20 is that we proceed to try to quant itate those exposures. 

21 The n w e will rel y on th e biokineti c model t o estimat e 

22 children' s blood-leads . 

23 We will look at adult males from the point of view 

24 of hypertension effects and have to discuss, in exposure 

25 terms , th e chang e in female/feta l ver y much in a qualitativ e 

EXECUTIVE COURT REPORTERS (301) 565-0064 
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sense in not being able to predict in the future what change;:; 

the air-quality levels: may have. 

DR. MUSHAK: Katie, if no one is advancing any 

Yugoslavian data ass important s if they are elevating it to 

the status of a useful data set, a3 1 that has happened is 

that some mention was made about there av e serial measures;. 

They probably have some idea of air-lead level;;;. 

DR. MAHAFFEY: Where I think we are, apparently 

ther e are a few result s on pregnan t 'women in th e wor k that 

Bill M a n t o n d i d -• - w I-1 i c hi i s, w h at, m a y b e o n t r i r e e s u b. j c? c t s — a n d 

ther e is som e cot her anecdota l kind of informatio n tha t is 

suggesting that blood-leads may go up in pregnancy or may go 

down in pregnancy. 

If we are not sure, because of prior exposure 

hi stor ies in mobi 1 i zat i on probab 1 y of biood-1 ead, whether cor 

not the blood-lead is going to go up or down, trying to 

relate that to a current air level strikes me as extremely 

chancy. 

DR. RABINOWITZ: It is hard for me to understand 

what the significance is of sequential blood-leads during 

pregnancy, whether they go up or down. I can'imagine a 

situation where blood-leads go down. That means lead goes 

into the fetus. 

I can imagine a situation where the blood-lead 

goes up. It still goes into the fetus. 

EXECUTIVE COURT REPORTERS (301) 565-0064 
P.54 

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it is hard for :now what to make? o 

health effects;- of whether the bl ood-1 eads g.s> up C'r down in 

pregnancy. 

DR. MUSHAK: Bl ood-1 ead going up? or down does not 

necessarily mean the fetus becomes a sink. Other things 

happen to lead. 

DR. RABINOWITZ: That's right. 

DR. MUSHAK: It gets excreted. 

DR. RABINOWITZ: It could be excreted or it could 

go to the fetus. I just don't know which it is. 

DR. MUSHAK: Oh, I think it goes to the fetus, but 

not exclusively. Let's quality it. 

DR. RABINOWITZ: I have heard the placenta called 

the third kidney. Maybe the placenta is a sink for this 

1 ead. 

So whether or not the blood-lead go up or down, I 

don't know what to make of that. I have enough faith, for 

some reason, in biokinetic modeling that if you somewhat 

diddle with the model and you do the right things, you might 

approach what is going on. 

I like all the caveats you said about maybe it is 

not worth doing if you cannot do it right. I agree with 

that. 

I would like to draw just one possibility to maybe 

fine tune it a little bit, that might be helpful. 

EXECUTIVE COURT REPORTERS (301) 565-0064 

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Can we tak e a lea f 

pregnanc y arid ssy , "Okay , i f 

thei r wisdom , tells ; us we ne?e?d thi s many mor 

f r om the calc i um s t or y i n 

yc.'U av e pregnant th e FDA, i n 

c.ium per monk 

. ng," and get an idea of how many micrograms of lead are 

grams ot 

nd t hen say, "We11, i n t he 

human body the ratio of lead to calcium is some certain 

number, depending con if you are high in lead or low in lead,," 

Then we can say, "Okay, for every gram of calcium 

you require, that is equivalent to how much skeleton you are 

I. 

en tier ing circulation from the skeleton from that. 

DR. MUSHAK: But you still ne?e?d a subject variable? 

bone-lead burden, and you can easily get it. 

DR. MAHAFFEY: The question are: Is the skeleton 

equally labeled? Is:- it equally available? 

This is where the data is so limited that we did 

not know what to write except that it seems reasonable, for 

whatever reason,—"reasonable" used in a strange way here: 

for lack of anything else to say about it—that there are 

probably physiologically many small pools of skeletal calcium 

in lead levels that are resorbed at different times. 

CHAIRMAN LARSON: The lead in the calcium? 

DR. MAHAFFEY: Yes. I don't think we know. 

CHAIRMAN LARSON: This has served a useful purpose 

in the discussion highlighting the fact that there is a 

paucity of data in that area. 

EXECUTIVE COURT REPORTERS (301) 565-0064 
P.56 

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DR. MAHAFFEY: We have something in Envi£O0H;:''G;t;:;:!. 

Researc.h that is cn.it in a month or two that is showing some 

increase in blood-1ead. There was one question in NHANES 

about menopausal status: that post-menopauisal women have a 

slight increase in blood-lead. I think it is about 15 or 20 

per cent. 

That is not dealing with peop1e who are 

spec i f i call y cost eopor ot i c . I f you had t hi i s spe?c i f i c 

o st eoporot i c g r oup, it wouId seem r ea son able that t he 

increase is substantially greater. 

DR. MUSHAK: I don't know that Tyrol had broke out 

a physiologically discernible osteoporotic. I believe it was 

an age-found analysis. 

When you analyze the same data, you better come up 

with the same answers. 

DR. MAHAFFEY: We hope so. 

[Laughter] 

DR. RABINOWITZ: Does it depend on whether or not 

they take estrogen? Do you have that information? 

DR. MAHAFFEY: I don't think that was in it. 

CHAIRMAN LARSON: I guess we will leave it at 

that. 

Another issue, the second one I would like to 

discuss, is sort of a second model, which.is the proposed 

approach to estimating the variance in blood-lead using the 

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g e ci m e? t r i c s t a n d a r d d e v i a t i o n . 

Is that appr oac li accept ab3. e t o t kie Subcommi 11 ee? 

We heard from Ian some comments; about possible examination of 

the range of values;. That might be a useful part of the 

Do you think it is necessary to look at a range of 

GSDs in this;? First of all, are we comfortable with this 

stp pr coach? 

You saw it used here in the case study where there*?' 

was a mean computed and then a variance about that mean thatwas computed for those plots based upon the GSDs. 

DR. MAHAFFEY: It h i n k there are two p r ob1 ems, at 

1 east. 

One is that the coefficient of variation just due 

to analytical as the blood-leads go down becomes bigger: that 

they have to somehow deal with that. 

I think that we are talking about blood-leads of 

under 10 and definitely under 5. This is a range that, given 

the NHANES was used for that data set, we did not have very 

many blood-leads under 5. 

So there is a lower boundary on that that is 

unclear what happens there. 

CHAIRMAN LARSON: Are you looking at levels in 

your NAAQS alternative assessment if you are thinking about 

this at those levels? 

EXECUTIVE COURT REPORTERS (301) 565-0064 
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*JMR:. COHEN: Yes „ T11er e w:i. .1. I be a who 1 e 1 ot o f 

children at 1 cower levels tt-an what ws are 'dealing with now 

no matter what we do with the air standard. 

We presented a range of GSDs in the report. We 

decide d t o p i c k co n e j u s t t o s i m p 1 i. f y t kt i n gs. Otherwise o n 

every table we can come up with we would have four move. 

We need to sort of focus the analyses down to a 

manageable level. We could look at the higher end of the GSD 

range as presenteci as thie cconservat i ve choice. 

We deci.ded to pick a mid-point because we are not 

sure what is going to happen in the future. It is a resally a 

tough call . 

MR. HAINES: The analytical variation, I think, of 

the lower blood-lead levels are a serious problem. We have 

thee problem with the underlying health studies, too, which 

had the same problem associated with them. 

I think our feeling is, A, if you can correct for 

it, B, is it appropriate to? You correct it on one side of 

the equation and it is uncorrected on the other side of the 

equation doing that. 

That, to me, is a perplexing problem how to 

address: A, what would you do in the first instance to fixit, if we could; but, B, do you fix part of it and then you 

still rely on the health effect studies for which it was not 

c or r ec t ed. 

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MR. COHEN; There is a pretty substantial 

dis c LI s s i ci n i n t h e c r i t e r i. a ci o c u m e n t o i' i c: CJ V r e c t i n g f o r 

analytica l variatio n an d th e effec t con the? GSD s fro m NHANES . 

W e c:l i. ci f i n d a s-iiialler varia n c e afte r c o rr e c t i n g f o r t h e 

a n a 1 y t i c a 1 v a. r i a n c e. 

For adults I remember it was 1.37 for urban whites 

versus; 1.33 if you do make the adjustment. We thought it 

was, like John said, inappropriate though because we would be 

c co r r e ct i n g o n o n e? s;- i. ci e a n d no t t h e o t hi e r . 

DR. MAHAFFEY: Ag a i n , t h osse wer e for b 1 ood -leads 

in, what, 15, 20, 25? 

MR. COHEN: Well, these were adults. They were 

10,15. 

DR. MAHAFFEY: I don't have the answer. 

MR. HAINES: I think the only approach is to make 

it clear in our report that we have made the correction. I 

think you have to proceed. 

I don't know how we could do it and whether or not 

it would be appropriate without making an adjustment across 

all the data bases. I am not sure we can do that. 

I think sometimes it introduces a degree of 

uncertainty in the results, but all we can do is point out 

that this exists, unless Jeff or Allan, or somebody, has a 

sol. ut i on for the pr ob 1 em. 

I think it is one of recognition and you have to 

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move? on „ 

CHAIRMAN LARSON: Mathematically speaking, it i. s 

pr esumabl y a more-? sensitive parameter than a simple 

multiplicative factor that you. might be changing by a certain 

only per s;pec: t i ' it is a sensitive paramet 

t h e f i n a 1 o u t c o m e you ciorvt have t o n ar i 1 y run 

all the detailed numbers, but give some sense of how 

sensitive that sensitive parameter is. 

DR. RABINOWITZ: On this sensitive parameter, we 

ci o n ' t h a v e a n y s e n s e f o r t hi e range it c o u 1 d acquire. 

MR. HAINES: That is the problem I see. 

We? know it prcobably exists, but we don't have any 

notion of what it is or what the magnitude of it is. 

DR. R AB I NOW IT 7.: The GSD i t se 1 f ? 

MR. COHEN: Of the ratio between that and the 

mean. 

DR. RABINOWITZ: There is a table in the document 

showing a whole bunch of different numbers. Then we heard 

about the same set, perhaps even a more limited range, that 

Ian mentioned in his study. 

I am quoting numbers 1.3, 1.4, 1.5 and 1.6. 

MR. HAINES: I think we were talking more of the 

analytical variation that impacts at this level — 

DR. RABINOWITZ: Oh, I'm sorry. I misunderstood 

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MR. HAINES: —vis-a-vi s GSDs that Jeffrey has 

ci i s c u s ss e d i rv t h e? r e? pi o r t . 

DR. MUSHAK: As an aside, I ques the-? analyti 

variance you see in the NHANES data set is not a VBry good 

analysis. You recall that was one of the arguments a the 

t i n i e? t hi a t w e r e? u s e? d t o a r g u e c o u n t e r p o i n t . 

01"ie c CJL.I 1 d show that by the good qua 1 i t y o f t he 

NHANES data-gathering analysis. I am not sure you could get 

a s m u c h with an y other data set, and c er t ai n1y n o t w i t h i t as 

it shifted the mean fcor the analytical challenge you have. 

It is just not going to do it. 

DR. von LINDERN: I remember I prefaced what I 

said with a guess. It was not quite a guess, but I think 

y o u hi a v e d o n e a g o o d j o b in ere a t ing t h i s s u b j e c t. 

I think your point is well taken: it is a very 

sensitive parameter. That is really what I felt is the gist 

to indicate that. 

DR. RABINOWITZ: This shows up again when you 

actually try to see if these standards are being met. By 

looking at blood-lead, you can see false positives or false 

negatives. 

It is the same problem showing up there also, I 

guess, basically. 

CHAIRMAN LARSON: Finally, on page 48, the 

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ques t i con : Can t hes e iiiodeli ng app r oac he s w e hav e d i s•:: u.ssed b e 

a p p 1 i e d t o o t kt e r ex p o;:; u r e s et s ? 

Thi s ma y not b e an all-inclusive-? list , but it 

gives some examples of what — 

DR. MUSHAK: We would want to go down the list, 

wou.l ci we? 

T h i s m o d e? 1 h a s a h i g h p o t e n t i a 1 f o r m i s c l-t i e f i f 

the Environmental Protection Agency and other offices get 

their hands on it. I mean that. 

MR. COHEN: Yes, please. 

DR. RABINOWITZ: Is it worth making a list of 

places where it should not be used? 

MR. COHEN: Yes. 

DR. MUSHAK: I think t hat i s almost an i n f i ni t e 

list. The thing is let's go with what they have. 

I think on the Super Fund sites, I think there is 

the caution indicated earlier. If one has some idea where con 

is, fine: that is, if you can assume that the pre- and postdifferential is at least in a linear segment of the overall 

c ur ve. 

The high-level intermittent drinking-water 

exposures. I think that is less troublesome. In other 

words, the only variable that you need concern yourself with 

is how much lead was taken in: that is, if you have a child 

consumption rate during the day—300 mills is one number 

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you , say , 

k, A V n. i i... r L.II_P • pp.inr 

ycou ge t a n am count o f lea d i n wa'i 

t h i s iit ci ci e 1 . 

I th i nk tiiat , aga i n , 

a i"i d I t h i i' t k t h a t is; the? ma i n c a •• 

1 sui* very „ i not.<ceci—an o it 

lite r wit i'l standin g water , 

v an d yo u coul d pump i t int o 

p ... ... -P.. I r-* ., ... J.. .; .... I- _[ _. .'.. .. 

::l':::- fjU OT I i, I I te' ~j>-. CJ I.- i in-rl U c:i I.- c:i 

a t Iter e un 1 ess: ycou are way 

o f f 11 o o s e levels , again y o u a r e i n 111 at n o n — 1 i n e a r pi CJi r on, 

You may want to acid comments to that. 

E-iut I think for even 100 to 200 micrograms per 

liter excursions fcor water lead, it is; probably okay. 

CHAIRMAN LARSON: I had some comments on the 

drinking water, which were that even though I don't doubt 

that it is probably a reasonable thing to do it is not clear 

to me? that this particular document lends credence to that. 

I guess it does. T he v a1i d a t ion e x ercises a s sumed 

a constant drinking water lead level across all the different 

areas. So it really did not test it. 

DR. MUSHAK: But the original validation of the 

model was dietary lead. Those were feeding studies. Those 

were not air chambers. 

CHAIRMAN LARSON: So find support for it in one of 

the sub-modules here. 

DR. MUSHAK: I think you could probably make a 

good case. 

CHAIRMAN LARSON: It is implicit you have to 

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accept tha t par t i cul ar study i n orattempted model . I n tha t sense, tl yr tco accept thi s larg e 

s does validat e that . 

t h e model i s tha t i t sta y i n some linea r range . 

Consec-jUent ly , al l of your input s and Lip t a Ices fro m differen t 

sources of pathways ; should giv e you some indicatio n tha t you 

a r e g o i n g f o r t hi a t rn e? d i u m i n t hi p?? 1 i n e? a r r a n g e?. 

You ar e barrin g empirical - dat a t o do that . 

MR. COHEN: Okay . 

DR. RABINOWITZ: Are there any caveats besides 

1i near i ty? 

DF:. MUSHAK: Of course. I mean, by definition, if 

you have a bolus of exposures from drinking water or anything 

else given and if you have your typical, say, suburban brand 

new plumbing 1ead-soldered drinking fountain and otherwise 

the child is wel1-nourished, et cetera, unless you test that 

blood-lead level and have it persist, then I am not sure what 

the toxicological point it. 

That is, you can go through an exercise and say 

the child's blood-lead would have been that high, but I don't 

know what to do with it in terms of regulating it. 

DR. MAHAFFEY: To me, there are lot of things to 

be considered here in terms of the patterns of exposure. If 

you have a short-term high exposure of lead in something like 

drinking water, at least for children, I am not sure we 

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real l y hav e t l o f understandin q wha t th e 

physiologica l res:-poi't;;e is ; goin g t o be : i f thi s absorbed . 

I s i t mor e likel y simpl y t o b e excrete d cor ar & yo u 

g co i n g t co hav e a t r a n s i e n t h i g h b 1 o o c J - • 1 e a d ? 

I don' t thin k we know . 

MR. COHEN: We don't , bu t I gue s •!- !-, ca f l ie Office of 

Drinking Water, nevertheless, wanted to know something. 

Anything that, I think, we would export to other 

pr cog rams; we w COLI Id try our besst to couch it in all the 

appropriate uncertainties; and try to make necessary 

ad just merits. 

I don't think we would use the same exact input 

p ar ame t ers f cor a 11 other applications. 

DR. MAHAFFEY: Again, as you s;aid, it is explained 

in the set of circumstances you note: 30 percent of the 

variat i on. 

If somebody wants to take this without having as 

much information as you have and say, "Okay, we can do this," 

and "Gee, this time we will explain 20 percent," I don't find 

that encouraging. 

MR. COHEN: If you try to predict individual 

blood-leads, it is right. 

DR. MUSHAK: What exactly are you objecting to? 

Are you objecting to the notion that if a child drank 100 

micrograms of lead in water in a given day, nothing would 

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happen? 

Is that thee point, or is it that the model is, mot 

u s-ef u 1 vis-a-vis similar calc: u 1 a t i or\- s; f cor a c h r con i c :J a i 1 y 

chi 1 d exposure'"' 

DR. MAHAFFEY: I gues;; my react i con — anci t hi s i r 

being Icind of blunt about it —i s that if we take peopl e who 

are going to drink water that is high in leead, it is 

reasonable? to think the blood--! ead is;- going to go up. 

How much do we really have to prove that it only 

goes, up 5 percent, 3 percent? 

DR. MUSHAK: But I think the Office of Drinking 

Water is not in the business of saying, "Well, obviously it 

goes up." I think they would like to hang a number off of 

that. 

The question is: Can the model be used to relate 

X micrograms in a single-shot expcosurc? with a child to 

micrograms per deciliter? That is the issue. 

On the face of it, I would say that given that be 

you could put around it, yes. I think you have less of a 

problem with this than in the prior case: the Super Fund 

sites and so on. 

Whether or not you have anything useful out of 

that I think is the more relevant question. If you could 

convince the Office of Drinking Water that, "Well, yes, we 

can give you a number; but what is its meat and potatoes in 

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terms ; of regulation?" , tha t is; another thi n 

CHAIRMAN LARS ! iPQrt M That sumponent a par t of our 

VlKOCiC-r-1 "t ci co u r in co del v a 1 i c j a t i co n , b u t i t i s certa i n 1 y 

i ndi vi dual 3. v J.. _. ... X. ^.. r.\ 

estec j a;; a component; i n a find of i tsel f . 

Certainly there is evidence and part of the review 

process here gives us; support for the fact that you can use 

that appi roach, but it would be misleading to -say that this 

review committee gave a calibrated model to the Office of 

D r i n k i n g W a t e? r . 

MR. HAINES: I think what I am hearing you say is 

that any time a model is exported, this one in particular, 

anybody using it has to approach it in a very cautious manner 

and make sure, in fact, the model produces plausible results 

for the application for which it is being used. 

DR. MAHAFFEY: If one wanted to study lead in 

drinking water, there are studies that have been carried out 

in Scotland that have looked at lead in drinking water. 

MR. COHEN: Yes. 

DR. MAHAFFEY: Why not do that? 

MR. COHEN: They use that where they can. 

DR. MUSHAK: You can pose that in relation to this 

model. You have the smelter studies. You have East Helena, 

et cetera. 

Why do it in aggregate/disaggregate models? Why 

do it biokinetically? 

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•T" . !--'-i ! •••-•). | T l * ... .! * » .. " , , .] , .1. i - .- -

!r\ ^ '.. •- 'fir:.fs I: i ;•; -...* y v.-v.-..-*:' ••-- i <...'-.'•-• •_• wu ;' '•' .;. '.*...''-.; CU..J '._*'_.•. C L :* i•...• -:> •:*-*• 

S v ':.:: l'"i S t ' p v•-* -H. I •! E * T I 'i ii^ : '*• •'.'.. C> '..• 'C X B f • C; 3. '{'• ~:\ V" 6/ ^:. J. J. V d O R ? t 

D R , MUSl-lAI::: Tha t i s quit e fixed , hi. gh but 

i.~ on c en t i* ate d . 

C l-l A 3! R M A N !.... A R 3 ON : Ar e a rt y CJ f t h e s e 1 i s t s o r o t h e r 

item s blinkin g out at yo u as; bein g particularl y dange r COLI s; 

a p p 11 c at i coi"is;':-' 

DR. MAHAFFEY: What about relative ranking of 

,4 4 .ex.... .... ... 

dii i t-.jr t.-ri 

L Li I..I i lutants based on daily intake estimate; 

DR. MUSHAK: I would think that that is somewhere 

b e? t ween 40, 000 an d 50, 000 feet high up t hi ere?. 

[Laughter 1 

DR. MUSHAK: And rising, yes. 

M R. H AIN E 3: A s f a r a s; m o d e ling i s ceo n c e r n e d , 

there is no way we cam produce a model that can have an 

i d i ot -pr oo f c ap on i t. 

[Laughter II 

MR. HAINES: What happens is that if the models 

are used by offices within the agency, the use of those 

models and the appropriateness of the input parameters will 

be examined by advisory committees as this use has been, and 

the Office of Drinking Water's use of the model will be 

reviewed by SAB. 

So I think the appropriateness of the model for 

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1 t.p /' 

the air~lead standards is what we probably can appropriately 

focus on right now and let other people worry about the other 

app 1 i c at i cons. 

I think we tried to provide a clear statement of 

our own reservations about the applicability and the 

appropriateness;; of the parameters, and we have been 

responsible in our use of those?. That is. as; much as we can 

do for anybody. 

CHAIRMAN LARSON: I think there is also some 

p r e s s u r e t o g e t r e? s e? r v ati o n s on the r e c co rd early. It m a y 

well turn out that some subsequent committee using this data 

c an c ome up with somet h i n g. 

MR. COHEN: It is like anything else in the 

scientific literature. 

CHAIRMAN LARSON: It is relative to the point in 

t i me. 

DR. RABINOWITZ: Is there somewhere in there that 

you say this should not be used for other pollutants? 

[Laughter 1 

DR. MAHAFFEY: I would say that the Clean Air 

Science Advisory Efoard appears to have a lot more lead 

consultants to it than some of the others. So I think the 

amount of lead review in the air part is based on 

observation, it seems, more than some others have. 

So while we cannot defend this model against other 

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i nc i.ir si cons; cor oth e i nap p r co pri ace i ..• s; e s;, wloe nee u c d tc:- bear in 

he air par?; has been very much reviewed. 

MR. HAINES: My guess cor. this topic, from my 

! I-.-.' r ::::• U t:'... I, J. VeI from hear i ng us trying 11 o sa J J J. S the 

S u tn c co mini tte e w o u 1 d q o fo r t h rar as, quote, exporting tht 

mcooei : that your view is i t s h o u Id be u n derta lc e n w i t hi c a u t i co n 

by other programs and appropriately reviewed as to its 

applicability across the board. 

I think you folks can put the? cautionary note on 

this and make it clear that it skiouid not be endorsement for 

purposes it within the air standards. That should not be 

construed as a blanket endorsement to all other applications. 

I think that is the point you are trying to get 

across. I think that is a reasonable prospectus. 

CHAIRMAN LARSON: I have made up my own list, but 

are there any other points that you would like to raise that 

you think impact the question of whether or not this becomes 

an adequate supplement, if you will, to looking at the 

alternate air-quality standards, given all the caveats of 

this written summary? 

I am not sure everybody is pleased with it, but 

are there any points I have missed? 

Go ahead. 

DR. RABINOWITZ: I just had a wish that when the 

results of the calculations of these models are presented 

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! "i es e C; 

blood-1ea d t o that , but th e percentag e 

n l y two significan t figu r 

[Laughter Ii 

MR. COHEN: 

7 sgree on, given the? 

l-i i est or y of how some of our standards have been sets the ,005 

percent of the population, fcor example?. 

CHAIRMAN LARSON: Do you have anything else? 

MR. HAINES: I just want to make sure that I am 

uri d esr st an d i n g whi at I am h e?ar i n g i n sunima t i on . 

G co ing d o w n your list of q u e s t i o n s, as far a s; our 

response to comments posed by the Subcommittee, I think I am 

reading you as saying what Jeff has laid out: The way in 

which we plan to approach these is appropriate and adequate-?. 

With respect to the models, I am reading the? 

Subcommittee as saying the application of the biokinetic 

mode l f o r c h i 1 d r e n h a s a r e? a s co n a b 1 e? a p p r o a c h f o r e? s t i. m a t i n g 

chil d blood-lead . 

When it comes to females, there is a great concern 

over the appropriateness of the approach. We should make 

this clear and try to explore any other ways we can address 

that in a better fashion. 

Where I am drawing the line is—and this is why I 

am coming down to the point—that one interpretation is: Do 

what we laid out; see if we have augmented the Yugoslavian 

data or any other sources; but make it very clear that, based 

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con adul t males;, not ieniales , et cetet 

cii sc uss exposui* e t o qua3. i t at i re set s 

,•••!,•-,,-.? •*- *•-•;•:., 

1 ••' l..-1 

a, co r a 11 e r n a. t i -rely co n 1 y 

s-ts and don' t try t o 

quant .itate because we dor a p p r co p r i at e t co co I s. 

CHAIRMAN LARSON: I could get wrong, but I got the 

latter as; the sense of the Subcommittee. 

MR:. HAINES: Okay. That is why I am posing it. 

DR. MAHAFFEY: And strike the word "female" and 

use "pregnant woman" be?cause? it is not females, per ses. 

MR. HAINES: I recognize that. 

DR. MAHAFFEY: T h e o c c u p ati o n a 1 p es o p 1 e h a v e? a 

whoie lot of trouble? with that. 

MR. HAINES: Okay. 

[Laughter 1 

MR. HAINES: In use of DSDs and that, I think we 

ha.ve laid out a range. I think the approach is agreed to by 

ther Subcommittee. 

CHAIRMAN LARSON: We had some discussion about a 

couple of those key parameters that go with the biokinetic 

model, just looking at the sensitivity analysis on the 

predicted soi1-1ead. 

I guess those are the two issues that were brought 

up and discussed. 

Anybody else? 

DR. McLAMB: I was not being facetious about 

estimating blood-leads in adult males. I would like to know 

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whether or net we are gc-i;"--, to . 

T•;•; vi--'-"---. p"ic'p-i: .•- " .--;••;• t "• it, . 

CHAIRMAN LARSON: We kpave not discusse d tha t 

fully . I gLitsss we wer e com'!' or t abl e tha t ther e was; adeuquat e 

d a t a f co r g co in g ahead wit h 11 -i at ap p r coach. 

DR. McLAMB: Okay . 

. -• | p A r .- . K.. * p.. i t ... r-, '-• --, p.p., i p • i i .. > ,r .p ... . i.. , _ .: 

L-h H .i fp.iif-ip-l L. ri r-. :r, i..p i - ; Wt-; W.L J. .I. U r a i K, "• U I I I e I- r i .11 l y , 

hopefully , t o the poin t tha t we can pass; around her e by way 

of summarising what we jus t cii scus;;sd, scome guidance. 

Thank ' you al l for patientl y meseting here thi s 

arte r no con. 

MR. HAINES: I want t o thank th e Subcommittee 

m e m ber s f co r w 0 r k i n g kv a r d 0 n th i s . 

CHAIRMAN LARSON: Wit h that , we cal l th e meeting 

adjourned . 

[ A t 4:05 p.m. , th e meeting was .concluded. 1 

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