OAR Box 1112 

Prepped by Ryan Dugan 

Document Number: 

92) ll-D-42 

Docket Number: 

A-83-22 

Printed 4/16/2008 9:12:10 AM Sheet 92 of 97 

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A-2Z-2.2- 5-D-H^ 

SAB-CASAC-86-024 

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON. D.C. 20460 

August 29, 1986 

Honorable Craig Potter 

Assistant Administrator for 

Air and Radiation 

U.S. Environmental Protection 

Agency 

Washington, D.C. 20460 

Dear Mr. Potter: 

Ifl 

II i l [, 

OFFIC E O F 

;-"i TH E ADMINISTRATO R 

I 1989 

EPA AIR DOCKET [J 

At the March 11-12, 1986 Clean Air Scientifi c Advisory Committee 

(CASAC) meeting, the Committee reviewed the second external review draft 

of the Staff Paper for Lead. In general, the CASAC found the document 

to be clea r and appropriate. The major comments provided by the Committee 

a t tha t meeting along with the major written comments submitted afterwards 

are formally summarized in this recommendation letter. 

The Committee recommends that the Agency undertake the following 

modifications to the Staff Paper for Lead: 

1. Revise the introduction to: 

- Provide a systematic catalogue and ranking of air and 

non-air sources of exposures. 

- More clearly explain tha t because of the phase-down of 

lead in gasoline, EPA's part of the lead problem, which 

was originall y a distributed source problem like other 

ambient pollutants, is becoming a problem of specific , 

well-localized sources. 

Sate other parts of the lead problem, like the paint problem 

over which EPA does not have authority, are stil l distributed 

source problems. The Staff Paper should also clarify tha t the 

primary mechanism of exposure for EPA's part of the problem 

(airborne emissions) is via ingestion of lead in settle d dust 

and surface dirt , not via direc t air exposure. This will require 

bette r data on soil/dust fat e and mass balance and children's 

intake. 

2. Revise the e>q?osure assessment to make i t cleare r tha t the 

primary sources for current and future exposures ar e point 

sources. In particula r the Staff Paper should: 

- Criticall y discuss the problems of using knowledge 

derived frcm area sources for studies of point 

sources. 
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- Focus and improve the material covered in Appendix B 

(especially Table B-2) since i t drives the analysis of 

the uncertainty. 

- Reevaluate the point source exposure estimates. 

- Discuss deposition and size distribution explicitly , both 

in terms of the deposition on and resuspension from 

ground surfaces, and in terms of the deposition in the 

respiratory tract . 

- Be more explicit about whom is being protected. The 

99.9% approach, as now employed, is ambiguous. 

3 . Since, in the future, ambient air lead will be attributabl e to 

a limited number of definable point sources, CASAC recommends 

tha t EPA consider regulating lead through point source controls 

rather than through the NAAQS. 

4. The discussion of measurement would be cleare r if i t were moved 

to the end so tha t the preceeding discussions could motivate it . 

Measurement poses two needs, with different data reguirements 

for each: -> • 

- Documenting the decline of the motor vehicle sources 

problem. 

- Controlling the problems of point sources. 

5. Explicitly evaluate the degree of protection against cardiovascular 

effects in,adult males provided by the blood lead and air lead 

levels developed t o protec t children against neurobehavioral 

effects. If these levels do not provide adequate protection 

against adverse cardiovascular effects in adult males, develop new 

recommendations to provide such protection. This should include 

an evaluation of the blood lead-blood pressure relationships in 

adult males, and its implication to the incidence of cardiovascular 

disease. 

6. The perinate should be included as a population a t increased 

ris k due t o prenatal exposure of the fetus and postnata l exposure 

of the lactating infant. This concern focuses^ on the fetus and 

infant, not on the pregnant mother. 

7. Emphasis should be increased on postdepositional exposures to 

lead as the major route of exposure to airborne lead. 
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8. The material on health effects should be moved forward so tha t 

the discussion on sources and exposures proceeds without 

interruption. 

The comments tha t form the basis for these recommendations were 

provided informally to the staff of the Office of Air Quality Planning 

and Standards afte r the close of the March 1986 meeting. This lette r 

constitutes the Committee's formal report to the Agency on this stage of 

the review of the NAAQS for Lead. 

The Committee appreciates the opportunity to provide comments on 

this important issue. 

Sincerely, 

.-\ ^p/^ 

Morton Lippmann, Ph.D. 

Chairman 

Clean Air Scientific Advisory 

Committee 

cc: Lee Thomas 

A« James Barnes 

Donald Ehreth 

Gerald Emison 

Lester Grant 

John O'Connor 

Terry Yosie 
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SAB-CASAC-86-023 

f t JB^ ^ UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

\^\C£j WASHINGTON. D.C. 20460 

%**o ^ 

August 29, 1986 

% 

OFFIC E O F 

T H E ADMINISTRATO R 

The Honorable Lee Thomas 

Administrator 

U.S. Environmental Protection 

Agency 

Washington, DC 20460 

Dear Mr. Thomas: 

The Clean Air Scientifi c Advisory Committee (CASAC) has completed 

i ts review of two documents related to the development of National Ambient 

Air Quality Standards (NAAQS) for Lead. These documents are the Air 

Quality Criteri a for Lead and Lead Effects on Cardiovascular Function and 

Stature : An Addendum to the U.S. EPA 1986 Document, Air Quality Criteri a 

for Lead, both prepared by the Agency's Environmental Criteri a and 

Assessment Office (ECAO). 

The CASAC's current review cycle for this ambient air pollutant has 

included public meetings on April 26-27, 1984, May 13-15, 1985 and 

March 11-12, 1986. At the May 1985 meeting, the Committee recommended 

tha t the ECAO revise the second external review draft of the Air Quality 

Criteri a for Lead by including an Addendum with a further evaluation of 

recent research concerning the relationship between hypertension and 

blood lead and the effects of lead exposure on childhood growth and 

stature . The Committee fel t tha t these two issues were significant 

enough to warrant specia l attention. 

The Committee reviewed the draft Addendum a t the March 1986 meeting 

and the fina l Criteri a Document and Addendum by mail in June and August 

1986, respectively. The CASAC unanimously concluded tha t both documents 

represent a scientificall y balanced and defensible summary of the current 

basis of our knowledge of the health effects literatur e for this pollutant. 

Several important issues are discussed in these documents which the 

Committee believes should be enphasized. In ligh t of the emerging evidence 

on the relationship between blood lead and hypertension ranging from 

levels > 30-40 ug/dl (micrograms per decilite r of blood) down to levels 

below 10-15 jug/dl, white males aged 40-59 have been identified as yet 

another subpopulation potentially a t risk. This is in addition to the 

other traditionall y accepted groups a t risk: preschool-aged children 

(age 6 and below) and pregnant wanen (due to the risk to the fetus). 
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In general, i t appears that the blood lead level a t which adverse 

health effects are recognized as beginning to appear has fallen rather 

sharply since 1977 when the previous Air Quality Criteria Document for 

Lead was published. This clearly has implications for the level of the 

standard and the appropriate margin of safety to consider when the NAAQS 

for Lead is to be revised. For example, i t is now believed that the 

onset of detectable heme synthesis impairment in children may occur a t 

blood lead levels starting around 10-15 jug/dl. This, along with the 

indications of increasing degrees of interference in pyrimidine and 

vitamin D metabolism, as well as alterations in central nervous system 

activity a t these same levels, may be argued as becoming bicmedically 

adverse. 

In addition, the emerging data on the effects of perinatial exposure 

to low levels of lead on physical and neurobehavioral development appears 

to indicate that fetal exposure to lead at levels as low as 15 jug/dl can 

have undesirable effects on infant mental development, length of gestation, 

and possibly other aspects of growth and development. 

A separate report will be prepared reflecting the Committee's final 

conclusions and recommendations on the NAAQS for Lead a t the time that 

the Agency's Office of Air Quality Planning and Standards completes the 

companion document, the Staff Paper for Lead (Review of the NAAQS for 

Lead: Assessment of Scientific and Technical Information). .t. . 

Thank you for the opportunity to present the Committee's views on 

this important public health issue. 

Sincerely, 

Morton Lippmann, Ph.D. 

Chairman 

Clean Air Scientific Advisory 

Committee 

cc: Mr. A. James Barnes 

Mr. Don Ehreth 

Dr. Les Grant 

Mr. Craig Potter 

Dr. Terry Yosie