Project Work Plan for

Revised Air Quality Criteria

for Lead

Notice

This document is a preliminary draft.

It has not been formally released by EPA

and should not at this stage be construed

to represent Agency policy. It is being

circulated for comment on its technical

accuracy and policy implications.

EPA United States

Environmental 

Protection Agency
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NCEA-R-1465

January 2005

CASAC Review Draft

Project Work Plan for 

Revised Air Quality Criteria

For Lead

National Center for Environment Assessment

Office of Research and Development

U. S. Environmental Protection Agency

Research Triangle Park, NC 27711
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DISCLAIMER

This document is an external draft for review purposes only and does not constitute U.S. Environmental

Protection Agency policy. Mention of trade names or commercial products does not constitute endorsement

or recommendation for use. 

PREFACE

This project work plan has been prepared as a managerial and management information tool for the

U.S. Environmental Protection Agency's National Center for Environmental Assessment Division in Research

Triangle Park, NC. It may be modified and amended from time to time, as necessary, to reflect actual project

requirements and progress. As a result, any proposed schedules and outlines, or any lists of technical

coordinator assignments, authors, or reviewers are subject to change.
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TABLE OF CONTENTS

DISCLAIMER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i

PREFACE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i

TABLE OF CONTENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii

I. INTRODUCTION ........................................................1

A. LEGISLATIVE BACKGROUND ........................................1

B. REGULATORY BACKGROUND ........................................2

C. PROJECTED SCHEDULE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

II. SCIENTIFIC BACKGROUND AND KEY ISSUES ............................6

A. LEAD AS A MULTIMEDIA ENVIRONMENTAL CONTAMINANT ...........6

B. HEALTH EFFECTS OF EXPOSURE TO LEAD . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

C. ECOLOGICAL EFFECTS OF EXPOSURE TO LEAD . . . . . . . . . . . . . . . . . . . . . . 10

III. ORGANIZATIONAL STRUCTURE AND PREPARATION/REVIEW 

PROCESS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

A. ORGANIZATION AND CONTENT OF REVISED LEAD DOCUMENT . . . . . . . 14

B. METHODS AND PROCEDURES FOR DOCUMENT PREPARATION . . . . . . . . 15

C. PERSONNEL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

D. APPROACH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

E. PUBLIC AND SCIENTIFIC REVIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

APPENDIX A: Proposed Contents of Revised Air Quality Criteria for Lead . . . . . . A-1

APPENDIX B: EPA Work Group for Air Quality Criteria for Lead . . . . . . . . . . . . . . B-1

APPENDIX C: NCEA-RTP Project Team and Other Technical Consultants . . . . . . . C-1

APPENDIX D: Science Advisory Board Clean Air Scientific Advisory 

Committee Members . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D-1
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I. INTRODUCTION

A. LEGISLATIVE BACKGROUND

Two sections of the Clean Air Act (CAA) govern the establishment, review, and revision of

National Ambient Air Quality Standards (NAAQS). Section 108 (42 U.S.C. 7408) directs the

Administrator of the U.S. Environmental Protection Agency (EPA) to list certain air pollutants that may

be reasonably anticipated to endanger public health or welfare and to issue air quality criteria for them. 

These air quality criteria (scientific bases for NAAQS) are to reflect the latest scientific information

useful in indicating the kind and extent of all identifiable effects on public health or welfare that may be

expected from the presence of a given “criteria” pollutant in ambient air.

Section 109(a) of the CAA (42 U.S.C. 7409) directs the Administrator of EPA to propose and

promulgate primary and secondary NAAQS for pollutants identified under Section 108. Section

109(b)(1) defines a primary standard as one that, in the judgment of the Administrator, is requisite to

protect the public health (see inset) based on the criteria and allowing for an adequate margin of safety. 

The secondary standard, as defined in Section 109(b)(2), must specify a level of air quality that, in the

judgment of the Administrator, is requisite to protect the public welfare (see inset) from any known

or anticipated adverse effects associated with the presence of the pollutant in ambient air, based on

the criteria.

Section 109(d) of the CAA (42 U.S.C. 7409) requires periodic review and, if appropriate, revision

of existing criteria and standards. If, in the Administrator's judgment, the Agency's review and revision

of criteria make appropriate the proposal of new or revised standards, such standards are to be revised and

promulgated in accordance with Section 109(b). Alternatively, the Administrator may find that revision

PUBLIC HEALTH EFFECTS

C Effects on the health of the general population,

or identifiable groups within the population,

who are exposed to pollutants in ambient air

C Effects on mortality

C Effects on morbidity

C Effects on other health conditions including

indicators of:

C pre-morbid processes,

C risk factors, and

C disease

PUBLIC WELFARE EFFECTS

C Effects on personal comfort and well-being

C Effects on economic values

C Deterioration of property

C Hazards to transportation

C Effects on the environment, including:

C animals

C climate

C crops

C materials

C soils

C vegetation

C visibility

C water

C weather

C wildlife
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of the standards is inappropriate and conclude the review by leaving the existing standards unchanged. 

Section 109 of the Clean Air Act (42 U.S.C. 7409) also requires that the criteria and NAAQS be reviewed

by an independent scientific review group, those review responsibilities being met by the Clean Air

Scientific Advisory Committee (CASAC) of EPA’s Science Advisory Board (SAB). 

B. REGULATORY BACKGROUND

On October 5, 1978 the EPA promulgated primary and secondary NAAQS for lead, under

Section 109 of the CAA (43 FR 46258). The primary standard and the secondary standard are the same: 

1.5 μg/m3

 as a quarterly average (maximum arithmetic mean averaged over a calendar quarter). The

standards were based on the EPA’s 1977 Air Quality Criteria for lead. Subsequent regulations reducing

the use of lead additives in gasoline were promulgated in 1985 (50 FR 9386), leading to substantial

reductions in ambient air lead concentrations. 

In 1986, the EPA published a revised Air Quality Criteria Document for Lead (Lead AQCD). The

1986 AQCD assessed newly available scientific information on the health and welfare effects associated

with exposure to various concentrations of lead in ambient air. The 1986 AQCD reviewed literature

through 1985 for information relevant to derivation of air quality criteria for lead. The document was

principally concerned with the health and welfare effects of lead, but other scientific data were also

discussed in order to provide a better understanding of the pollutant in the environment. Thus, the 1986

document included chapters that discussed the atmospheric chemistry and physics of the pollutant;

analytical approaches; environmental concentrations; human exposure and dosimetry; physiological,

toxicological, clinical and epidemiological aspects of lead health effects; and lead effects on ecosystems. 

An Addendum to the 1986 Lead AQCD was also published along with it in 1986 (U.S. Environmental

Protection Agency, 1986). Subsequently, a supplement to the 1986 Lead AQCD/Addendum was

published by EPA in 1990 (U.S. Environmental Protection Agency, 1990). That 1990 supplement

evaluated still newer information emerging in the published literature concerning (1) lead effects on blood

pressure and other cardiovascular endpoints and (2) the effects of lead exposure during pregnancy or early

postnatally on birth outcomes and/or on the neonatal physical and neuropsychological development of

affected children. 

The evaluations contained in the 1986 Lead AQCD/Addendum and the 1990 Supplement provided

scientific inputs to support decision-making with regard to review and, as appropriate, revision of the

Lead NAAQS and they were drawn upon by EPA’s Office of Air Quality Planning and Standards

(OAQPS) in preparation of an associated Lead Staff Paper. After consideration of evaluations contained

in these documents, EPA chose not to propose revision of the Lead NAAQS. 
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Changes in relative contributions of various lead sources and exposure pathways to human

exposures in the United States, and EPA actions to reduce such exposures also provide important

background for this review. Since 1978, the amount of lead emitted into the air nationally has markedly

declined. From 1982 to 2002, for example, lead emissions into the air decreased by 93 percent, and the

average air quality concentration of lead decreased by 94 percent from 1983 to 2002

(http://www.epa.gov/airtrends/lead2.html). Total lead emissions into the air decreased from about

220,000 tons in 1970 to less than 4,000 in 1999. This decline is mainly attributable to EPA’s regulatory

efforts to reduce the content of lead in gasoline (http://www.epa.gov/airtrends/lead2.html), which has

substantially altered basic patterns of air lead emissions in the United States. Emissions from stationary

sources have also been greatly reduced (http://www.epa.gov/airtrends/lead2.html, Fig. 2-11); however,

given the even greater reductions in emissions from transportation sources, industrial processes (including

smelters and battery manufacturers) now constitute a larger percentage of remaining lead emissions to the

atmosphere (id., Fig. 2-12). (See generally (http://www.epa.gov/airtrends/lead2.html). In short, lead

emissions into the atmosphere decreased greatly in the 1980's and 1990's, a trend that has continued to the

present. As a consequence, airborne lead now represents only a relatively small component of total

exposure to lead, such that the principal sources of U.S. lead exposure in the most sensitive population

(young children) are through non-inhalation pathways (such as lead in deteriorating paint, food, drinking

water, dust, and historically contaminated soil). 

Since the 1980's, EPA has played a major role in working to reduce the main sources of lead

exposure for most children, including deteriorating lead-based paint, lead contaminated dust, and lead

contaminated residential soil (http://www.epa.gov/lead/). For example, EPA has established standards

for lead-based paint hazards and lead dust cleanup levels in most pre-1978 housing and childoccupied facilities, and is now developing standards for those conducting renovation activities that

create lead-based paint hazards and for the management and disposal of lead-based debris

(http://www.epa.gov/lead/regulation.htm). Also, EPA has developed standards for management of

lead in solid and hazardous waste, oversees the cleanup of lead contamination at Superfund facilities,

and has issued regulations to reduce lead in drinking water (http://www.epa.gov/lead/sources.htm). 

Beyond specific regulatory actions, the Agency’s Lead Awareness Program continues to work to

protect human health and the environment against the dangers of lead by conducting research and

designing educational outreach efforts and materials (http://www.epa.gov/lead/). 

Since the 1980's, EPA has also promulgated regulations under section 112 of the Act,

42 U.S.C. § 7412, to address emissions of lead components and other toxic pollutants from both primary

lead smelters and secondary lead smelters (40 CFR Subparts X and TTT). Under section 112(d), these

emission standards are to require “the maximum degree of reduction in emissions” that are “achievable.” 
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EPA promulgated section 112(d) standards for secondary lead smelters on June 23, 1995 (60 Fed. Reg.

3587) and revised them on June 13, 1997 (62 Fed. Reg. 32209) followed by promulgation of section

112(d) standards for primary lead smelters on June 4, 1999 (64 Fed. Reg. 30194). 

C. PROJECTED SCHEDULE

On November 9, 2004, EPA’s National Center for Environmental Assessment Division in Research

Triangle Park, NC (NCEA-RTP) announced official initiation of the current periodic review of air quality

criteria for lead. More specifically, under processes established in Sections 108 and 109 of the CAA, the

EPA began by announcing in the Federal Register (69 FR 64,926) the formal commencement of the

review with a call for information. In addition, EPA has prepared this Lead AQCD Work Plan, a draft of

which is now being made available for review by CASAC and the public, to communicate the process and

timeline for development of a revised Lead AQCD. After carefully assessing and evaluating pertinent

new studies, the EPA will first prepare preliminary draft chapters for a revised criteria document and

subject them to expert review at public workshops. After consideration of comments received at the

workshops, appropriate revisions will be made in the draft materials and a First External Review Draft of

the entire revised document will be made available for review and comment by CASAC and the public. 

EPA expects that, after consideration of CASAC and public comments, it will be necessary to prepare a

Second External Review Draft of the revised Lead AQCD for further review by CASAC and the public

before EPA completes the final version of the Lead AQCD. Publication of the final document and its

availability to the public will be announced in the Federal Register. Table 1 shows the projected schedule

for the criteria document revision process. 

Drawing upon evaluations in the Lead AQCD and other lead exposure/risk analyses, the EPA’s

Office of Air Quality Planning and Standards (OAQPS) staff will prepare a draft Lead Staff Paper

assessing policy implications of key information in the Lead AQCD and posing possible options for the

EPA Administrator to consider regarding whether to retain or, if appropriate, revise the Lead NAAQS. 

The draft Staff Paper and analyses will also be made available for review by CASAC and the public. 

Taking into account CASAC and public comments, final revisions will be made in the Lead Staff Paper,

and it will provide information for decisions to be made by the EPA Administrator regarding possible

retention or revision of the Lead NAAQS. 
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Table 1. Proposed Schedule for Development of Revised Lead Air Quality Criteria

Document (Pb AQCD) 1

Major Milestones Target Dates

 1. Literature Search Ongoing

 2. Federal Register Call for Information November 2004

 3. Prepare Draft Pb AQCD Project Work Plan Nov-Dec 2004

 4. Release Draft Project Plan for Public Comment/CASAC Review January 2005

 5. Public Comment Period Jan/Feb 2005

 6. CASAC/SAB Public Meeting to Review Project Work Plan March 2005

 7. Workshop Drafts of Pb AQCD Chapters May/June 2005

 8. Peer Consultative-Review Workshop(s) July/August 2005

 9. Release First External Review Draft January 2006

10. Public Comment Period (90 days) Feb-April 2006

11. CASAC/SAB Public Review Meeting (First Ext. Rev. Draft) April 2006

12. Release Second External Review Draft September 2006

13. Public Comment Period (60 days) Oct-Nov 2006

14. CASAC/SAB Public Review Meeting (Second Ext. Rev. Draft) December 2006

15. Final Lead AQCD February 2007

1 Proposed schedule may be modified from time to time, as necessary, to reflect actual project requirements and progress.
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II. SCIENTIFIC BACKGROUND AND KEY ISSUES

Numerous issues were identified by authors and reviewers of the 1986 Lead AQCD/Addendum

and the 1990 Supplement (U.S. Environmental Protection Agency, 1986, 1990) as being relevant to the

development of lead criteria. Additional issues were identified in the course of public discussion and

CASAC review of draft versions of those earlier AQCD materials and/or the associated Lead Staff Paper,

and some further issues have begun to emerge since then as being of potential public health concern. 

By way of introduction to the types of issues anticipated to be considered in the current lead criteria

review, the next several sections each open with concise presentation of some pertinent background

information on a given general category or topic, followed by listing of a number of the more important

issues as illustrative of the types of questions to be considered in the current review of lead criteria. 

Many of these issues were addressed by previous reviews. This review will consider any newly available

evidence as it may pertain to potential affirmation or revision of previously-stated key findings or

conclusions. 

A. LEAD AS A MULTIMEDIA ENVIRONMENTAL CONTAMINANT

Lead is a toxic metal that can produce a variety of physiological and, ultimately, pathological

effects in humans and can also have adverse effects on the environment. As illustrated in Figure 1,

human exposure occurs through multiple pathways, including primarily ingestion of lead in media such as

food, water, soil, and dust, as well as inhalation of airborne lead. Because health effects in humans are

associated with varying levels of lead in the blood and because all exposure pathways contribute to blood

lead levels, health risks are a function of total exposure. Thus, the evaluation of potential health risks

associated with exposures to concentrations of lead in the air must also take into account estimated

exposures and blood lead impacts of lead derived from other media (e.g., food, water, etc.). As a result,

considerable attention will be accorded in the revised Lead AQCD to delineation of information useful in

facilitating understanding of lead as a multimedia environmental contaminant, including characterization

of relative contributions of various exposure pathways to lead burdens in humans and ecosystems and

relationships of such lead burdens to consequent human health and environmental effects. 

Examples of important key issues related to delineation of lead as a multimedia environmental

contaminant are provided below. 

1. Physical and Chemical Properties of Lead and Measurement Methods

• What are important chemical and physical features of inorganic lead and organic lead compounds

encountered in the environment?
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• What are key features of sampling and analytic methods employed for measurement of lead in

environmental and biological media?

• What are appropriate quality assurance/quality control approaches to help ensure reliability of

such measurements? 

2. Sources, Emissions, Transport, and Environmental Fate of Atmospheric Lead

• Long-Term Historic Trends in Atmospheric Lead Emissions and Environmental Contamination.

• What are more recent trends in atmospheric emissions in the United States since the 1970's?

• How important is the downward deposition of lead onto surfaces accessible by humans?

• What are the spatial concentration patterns of anthropogenic lead emissions and how do these

differ from natural emissions?

• What fraction of observed U.S. ambient air lead concentrations can be attributed to anthropogenic

emission sources? 

• To what extent does long-range transport of lead emitted in other countries contribute to U.S.

ambient air lead levels? 

Figure 1. Principal pathways of lead from the environment to human consumption. Heavy arrows

are those pathways discussed in greatest detail in the 1986 Lead AQCD. 

Source: U.S. Environmental Protection Agency, Air Quality Criteria for Lead, Volume II of IV,

EPA/600/8-83/028bF (June 1986).
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3. Multimedia Human Exposure and Dosimetry

• What are the main multimedia/exposure pathways accounting for human environmental lead

exposures in the United States since the 1970's?

• What are current typical lead concentrations currently encountered by sensitive U.S. populations

via different major exposure pathways, e.g., air, food, water, etc.?

• What is the current status of population-based information on total human lead exposure and

spatial and temporal patterns of exposures of sensitive population groups?

• What tissue or fluid lead concentrations can serve as useful biomarkers of short- or long-term

lead exposure?

• What other types of biomarkers are useful as indices of short- or long-term lead exposures?

• How do social factors (e.g., human activity patterns and variable avoidance behaviors) affect lead

exposures of sensitive population groups?

• What genetic/physiologic factors influence lead exposure and the magnitude of lead

uptake/biological retention?

• What are features of currently available biokinetic models that are useful for projecting likely

impacts of multimedia human lead exposures (via air, food, water, etc.) on internal body burdens

as indexed by blood lead levels, etc?

B. HEALTH EFFECTS OF EXPOSURE TO LEAD

Decision-making underlying establishment of the 1978 primary Lead NAAQS took into account

consideration of the following key issues: 

(1) Determination of blood lead (PbB) concentrations associated with unacceptable risk of adverse

health effects, especially in infants and young children as key sensitive population; 

(2) Characterization of PbB distributions typical of U.S. pediatric populations;

(3) Determination of target level for average PbB concentration to keep PbB levels of given

percentage of sensitive population group below concentrations associated with unacceptable health risks;

(4) Characterization of typical relative contributions of different multimedia lead exposure

pathways (food, water, air, soil, etc.) to U.S. pediatric PbB levels; and 

(5) Determination of allowable air lead concentrations (i.e., the NAAQS) , taking into account

average contributions from other multimedia lead exposure pathways (e.g., via food, water, etc.).

One of the most controversial and intensely debated issues was the first listed above, i.e., the

determination of blood lead levels associated with unacceptable risk of adverse health effects. This
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determination was based on the 1977 Pb AQCD characterization of health effects associated with acute

and more chronic exposure to lead resulting in internal lead body burdens indexed across a wide range of

blood lead levels in adults and, of most concern, in young children, infants, and the unborn (in-utero)

fetus. This included qualitative delineation of types of lead effects documented by clinical and

epidemiological observations (as also supported by experimental animal studies) and characterization of

quantitative dose-response relationships. The latter included estimation of lowest-observed effect levels

for induction of: (a) clearly adverse, clinically evident classical signs and symptoms of acute lead

poisoning, such as (1) indications of life-threatening lead encephalopathy (serious central nervous system

damage most often seen in infants and young children and often leading to permanent severe mental

retardation and learning disabilities among survivors) documented to be associated with acute high-level

lead exposures resulting in very high blood-lead levels or (2) other signs of peripheral nerve damage

(as indexed, for example, by slowed nerve conduction velocities), anemia, indications of renal damage

and/or gastrointestinal symptoms (e.g., colic) observed in young children at somewhat lower blood lead

levels (the occurrence of a sufficiently severe constellation of the above types of acute lead poisoning

signs and symptoms typically warranting chelation and other types of immediate medical treatment). 

It also included (b) much more subtle and difficult to detect indications in asymptomatic infants and

children of less severe but still serious nervous system impacts (as indexed by IQ decrements or various

other types of sensitive tests of neurobehavioral or psychomotor functions) and/or more moderate red

blood cell impacts reported to occur at still lower blood lead levels but seen as likely collectively

constituting adverse health effects; and (c) much smaller magnitude biological or pathophysiological

effects of lead unlikely to be of medical concern (e.g., initial biochemical impacts on heme synthesis that 

occur starting at very low blood lead levels and increase in magnitude as blood lead levels become more

elevated). Subsequent studies assessed in the 1986 Lead AQCD/Addendum and the 1990 Supplement

provided further evidence substantiating the above types of findings and reported observed effect levels

for neurobehavioral impacts that extended to still lower PbB values than previously reported. 

Among the more important health-related issues that are anticipated to be considered in the current

Lead NAAQS review as part of the basis for decisions on the primary Lead NAAQS are those listed

below. 

1. Biological Mechanisms of Action

C What are mechanisms and time-courses associated with lead-induced subcellular, cellular, and

tissue injury, repair, and/or remodeling?

C What are the effects of age, gender, and pre-existing disease on cellular and tissue responses to

lead-induced injury?
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C In particular, to what extent does lead affect heme synthesis at varying lead exposure levels and

what are consequent impacts on various tissue or organ system functions?

2. Effects of Repeated Short-term, Prolonged, or Long-term Lead Exposure on Potential

Histopathologic, Pathophysiologic and Clinical Sequelae of Disease

C What levels and/or patterns of lead exposure are associated with retardation of growth rate in

fetuses, infants, and children?

C What levels of exposure (indexed by blood, bone, teeth lead levels) early in development are

associated with induction of neurological/neurobehavioral deficits?

C To what extent do lead-induced neurobehavioral/growth effects early in development persist and

have long-term sequelae?

C To what extent does long-term lead exposure contribute to postmenopausal osteoporosis,

formation of cataracts, or other health problems encountered most typically in older population

groups? 

C What evidence exists for genotoxic, carcinogenic, and/or co-carcinogenic effects of lead?

3. Sensitive Populations and Factors that Enhance Susceptibility

C What environmental and host factors (e.g., demographic, socioeconomic, genetic) are associated

with increased vulnerability or susceptibility to short- and long-term exposure to lead?

C Does lead exposure exacerbate pre-existing health conditions? If so, what is the nature of

enhanced health effects in persons with pre-existing health conditions who are exposed to lead?

C What are the quantitative relationships between ambient lead exposures and the frequencies of

occurrence of these effects?

C. ECOLOGICAL EFFECTS OF EXPOSURE TO LEAD

Lead occurs in various forms in the environment. Ionic lead (Pb2+), lead oxides and hydroxides,

and lead-metal oxyanion complexes are the general forms of lead released into soil, groundwater, and

surface waters. Pb2+ is the most common and reactive form of lead, forming mononuclear and

polynuclear oxides and hydroxides. The form of lead in the environment greatly influences the

bioavailability and toxicity to various biota.

Lead can accumulate in the terrestrial environment in soils, microorganisms, and plants. The forest

canopy is the functional interface between 90 percent of the Earth’s biomass and the atmosphere. 

Scavenging of atmospheric lead by foliage is a significant entry route of Pb into terrestrial ecosystems. 

Soil-borne lead can be directly toxic to soil microorganisms and disrupt decomposition and mycorrhizal
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processes. Once captured, lead persists within terrestrial ecosystems for decades, if not centuries. Lead

can enter adjacent aquatic systems by interactions between the terrestrial and aquatic environment.

Lead can also accumulate in sediments of aquatic ecosystems and serve as a source of

contamination to benthic organisms over long periods of time. Aquatic macrophytes can accumulate lead

from sediments and introduce lead into the aquatic food chain through the activities of plant grazers. 

Uptake of lead directly from the water column can also contribute to total lead body burdens in pelagic

aquatic species. Lead can move up the food chain and ultimately impact human health through

consumption of lead-tainted fish and shellfish.

The previous review (U.S. Environmental Protection Agency, 1986) indicated that remaining

uncertainties in available data for a number of environmental effects categories increased the difficulties

associated with characterizing qualitative or quantifiable risks to various components of agronomic,

forested, and natural ecosystems. The following issues tend to center around addressing such

uncertainties and provide an overall framework for assessing new scientific information that should likely

be considered to support selection of an appropriate secondary lead NAAQS protective of crops, natural

vegetation, and ecosystem components and processes. 

1. Exposure Dynamics: monitoring to determine ambient lead concentrations encountered in urban

and rural farm/forest areas, exposure patterns (episodes), concentrations vs flux, relationship between

chamber and field exposure data, plant uptake;

a. Modeling

C What is the state of the science in modeling lead concentration gradients and deposition velocities

across plant canopies, plant communities, or multiple ecological resource landscapes?

C How precise and accurate are these models?

C How well can these models be extrapolated temporally and spatially within or across different

forest types, crops, watersheds, basins, ecophysiographic regions, the urban-rural interface, etc.?

C Can passive samplers be useful to “fill in the gaps” in model-derived lead concentrations at remote

areas where continuous lead monitoring is not routinely performed?

b. Exposure Regimes

C How do episodic exposures (predisposition) alter plant or animal responses to chronic, cumulative

lead exposures? 

C How do we translate results from controlled exposure studies which are typically conducted with

single species/organisms (e.g., tree seedlings or crops) to whole trees, forest stands, farm land,

lakes, estuaries, ecosystems, watersheds, airsheds, or ecophysiographic regions?

C Can data from remote sensing platforms be useful in understanding local, regional, national,

and global lead transport and deposition? 
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2. Plant/Animal Response and Mode of Action: biological, chemical and physical responses,

especially cellular biochemical/physiological mechanisms; individual plant sensitivity/ genetic

composition; site/habitat influences; pest, disease, and abiotic stress interactions;

a. Plants

C Is there new information regarding the mode of action of lead once it enters a plant?

C Are there genetic markers that can be identified using state-of-the-art molecular biological

methodologies that differentiate lead tolerant and intolerant cultivars and species?

C What is known about lead’s effects on ecosystem components singly and in combination with other

air pollutants?

C How does lead, both singly and in combination with other air pollutants, influence plant-pathogen

and plant-pest interactions?

b. Wildlife

C Are lead exposure effects on wildlife similar to human exposure effects? 

C Has lead altered the nutritional content of forage for domestic animals or wildlife populations?

C What is known about lead’s effects on faunal ecosystem components singly and in combination

with other air pollutants?

c. Aquatic organisms

C How important is lead uptake from sediments in lead accumulation in aquatic plants and animals?

C How important is methylation in lead mobility and bioavailability in aquatic systems?

C To what extend is lead biomagnified up the food chain?

3. Ecosystems: exposure/response relationships of sensitive individual plant species and forest trees to

lead under ambient conditions; impact of lead exposure on interspecific competition on both aboveand below-ground interactions and on ecosystem products and services.

a. Biodiversity

C Does lead influence the biodiversity of ecological systems?

b. Terrestrial-Aquatic Interface

C Have terrestrial ecosystem effects of lead exposure affected aquatic ecosystems?

C Has lead altered the nutrient cycling in forested catchments that may manifest themselves as

changes in water chemistry at the stream and watershed levels?

4. Assessment: assessment of economic impacts on products (crops, forests, fish, shellfish, etc.) and

ecosystem services, benefits derived from control of lead exposures. 

a. Economics

C Have new and innovative methods evolved since the last criteria document for monetizing

ecosystem services and non-consumptive use products (e.g., aesthetics, recreation, plant nutritional

quality for wildlife)?
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C To what extent can credible estimates be derived for economic impacts of lead on consumptive-use

ecosystem products (e.g., crop yields, fish yields, shell fisheries, and timber)?

b. Scaling Up

C What recent advances, if any, now allow for localized or spatiotemporally disparate data sets to be

aggregated for regional ecological effects assessments?

C Can critical loads be determined for sensitive ecosystem components?
January 2005 DRAFT – DO NOT QUOTE OR CITE 14

III. ORGANIZATIONAL STRUCTURE AND

PREPARATION/REVIEW PROCESS

A. ORGANIZATION AND CONTENT OF REVISED LEAD DOCUMENT

The updated Lead AQCD will critically evaluate and assess scientific information on the health and

welfare effects associated with exposure to the concentrations of this pollutant in ambient air. The

revised document is not intended to be an exhaustive review of the literature. Rather, the cited references

will reflect the current state of knowledge on the most relevant issues pertinent to decisions on possible

Lead NAAQS revision. Although emphasis will be placed on the presentation of health and welfare

effects data, other scientific data will also be presented and evaluated in order to provide a better

understanding of the nature, sources, distribution, measurement, and concentrations of lead in ambient air,

as well as the measurement of population exposure to lead. 

The focus of the selected scientific information in the text will be on literature published since the

previous review of the air quality criteria for lead. Emphasis will be placed on studies conducted at or

near lead concentrations found in ambient air. Other studies may be included if they contain unique data,

such as the documentation of a previously unreported effect or of a mechanism for an observed effect; or

if they were multiple-concentration studies designed to provide exposure-response relationships. 

Key findings and conclusions from the 1986 Lead AQCD/Addendum and 1990 Supplement will

briefly be summarized at the outset of discussion of a given topic, with appropriate reference back to the

previous materials. Important prior studies will be more specifically discussed if they are open to

reinterpretation in light of newer data and are judged to be potentially useful in decisions on revision of

the standards for lead. Generally, only information that has undergone scientific peer review and has

been published (or accepted for publication) in the open literature will be considered in the criteria

document. Exceptions may be made depending on the importance of the subject information and its

pertinence to criteria development for Lead NAAQS, as determined in consultation with CASAC. 

The proposed structure of the document will begin with an Executive Summary and Conclusions.

Chapter 1 (Introduction) will present information on the legislative background and purpose of the

document, provide a brief introduction to key issues to be addressed, and present an overview of the

organization of the document. Chapter 2 will provide information on the physics and chemistry of lead,

as well as sampling and analytic methods for measurement of lead concentrations in various

environmental and biological media. Chapter 3 will cover sources, emissions, transport, and

deposition/fate; and Chapter 4 will cover environmental concentrations, patterns, and multimedia

exposure pathways. Chapter 5 will discuss dosimetric issues, focused mainly on modeling of multimedia

exposure impacts on human internal lead burdens, as indexed by blood or bone lead concentrations. 

Chapters 6 and 7 will discuss toxicologic studies of lead health effects in humans and laboratory animals,
January 2005 DRAFT – DO NOT QUOTE OR CITE 15

as well as clinical and epidemiologic studies. Chapter 8 will then provide an integrative synthesis of key

information regarding human lead exposures and health effects. Chapter 9 will deal with ecological and

other environmental effects of lead. The proposed chapter topics are provided in the inset below. See

Appendix A for a more detailed outline of proposed contents to be included in the revised Lead AQCD.

Chapter Topics for Revised Air Quality Criteria for Lead

Executive Summary

Chapter 1 Introduction

Chapter 2 Chemical and Physical Properties and Measurement

Chapter 3 Sources, Emissions, Transport, and Deposition 

Chapter 4 Environmental Concentrations and Pathways to Human Exposure

Chapter 5 Models of Human Exposure, Uptake, and Biokinetic Distribution of Lead

Chapter 6 Toxicologic Effects of Lead in Laboratory Animals

Chapter 7 Epidemiological and Clinical Studies of Lead Effects in Humans

Chapter 8 Integrative Synthesis of Human Exposure and Health Risks

Chapter 9 Environmental Effects of Lead

B. METHODS AND PROCEDURES FOR DOCUMENT PREPARATION

Responsibilities for developing the revised Lead AQCD will be essentially the same as those used

for recent criteria documents, with additional emphasis being placed on more extensive coordination and

collaborative inputs from various participating EPA units. Briefly, the respective responsibilities are as

follows. The Research Triangle Park Division of EPA’s National Center for Environmental Assessment

(NCEA-RTP) will have lead responsibility for preparation of the updated Lead AQCD. The Director of

NCEA-RTP has appointed a project manager and team with responsibility for developing the present

project work plan for preparation of the document. Development of the plan has been facilitated by input

from other EPA program and policy office staff among those listed on the EPA Lead Criteria Work

Group (see Appendix B). This resulting draft project plan is being made available for CASAC and public

review and will then be revised, as appropriate. It will also be further updated, as appropriate, to reflect

any major future changes and/or progress in its implementation. 

A literature search has been ongoing to collect references on the health and ecological effects of

lead. Additional literature searches are also underway for other respective areas to be covered in the

criteria document; and NCEA-RTP has developed an information base to access the references and

provide quality assurance and quality control functions. Specific chapter or section authors are being

selected on the basis of their expertise in the subject areas and their familiarity with the relevant literature. 
January 2005 DRAFT – DO NOT QUOTE OR CITE 16

Both EPA and non-EPA scientific experts will be involved in this effort. The main focus of the revised

criteria document will be on evaluation and interpretation of data that deal with the effects of airborne

lead on human health and welfare. One or more peer consultation workshops will be convened to discuss

draft criteria document chapters and will focus on the selection of studies included in the chapters, the

potential need for additional information to be added to the chapters, and the quality of the summarization

and interpretation of the literature. The respective authors of the draft chapters will revise them on the

basis of the workshop discussions. After resolution of outstanding issues and comments derived from the

workshops, NCEA-RTP will release the First External Review Draft of the revised Lead AQCD for

public comment and CASAC review. Then, revisions will be made on the basis of the public comments

and CASAC review. EPA expects that it will be necessary to make a Second External Review Draft

available for further CASAC and public review before EPA completes and releases the final version of

the revised Lead AQCD. Preparation of an updated Lead Staff Paper, drawing upon key findings and

conclusions from the Lead AQCD and other related exposure/risk analyses, will be carried out by EPA’s

Office of Air Quality Planning and Standards (OAQPS). 

C. PERSONNEL

Dr. Robert W. Elias will serve as the NCEA-RTP project manager responsible for overall

coordination of the Lead AQCD preparation effort. Drs. Lester D. Grant and J. Michael Davis will

provide overall technical guidance for the health effects aspects and Dr. Timothy Lewis for the ecological

effects aspects of the document. Other NCEA-RTP project team members who are to provide overall

coordination and technical inputs for individual chapters are as follows: Dr. Joseph Pinto for the chapter

on lead chemistry and measurement methodologies; Dr. Robert Elias, Dr. Joseph Pinto, Ms. Beverly

Comfort, and Mr. William Ewald for the chapter on environmental concentrations, patterns, and potential

exposures; Dr. Robert Elias for the chapter on lead biokinetic modeling; Drs. Lori White, James Brown,

Srikanth Nadadur, and J. Michael Davis for the chapter materials dealing with toxicological effects in

laboratory animals and humans; Drs. Dennis Kotchmar and Ji Young Kim for review and evaluation of

epidemiological studies; and Dr. Timothy Lewis for the chapter on environmental effects. Additional

technical assistance on air quality, health effects, and ecological effects will be obtained from EPA

scientists in EPA’s National Exposure Research Laboratory (NERL), National Health and Environmental

Effects Research Laboratory (NHEERL), and the Office of Air Quality Planning and Standards

(OAQPS), as appropriate and needed. As needed, scientific expertise will also be obtained from outside

EPA, utilizing contractual arrangements with non-EPA experts. Members of NCEA-RTP’s project team

and other EPA and non-EPA personnel expected to contribute to the document are listed in Appendix C;

examples of the pool of experts that EPA expects to tap to assist in development of the Lead AQCD as
January 2005 DRAFT – DO NOT QUOTE OR CITE 17

potential authors or contributors of written materials or serving in peer consultative or reviewer roles for

review of workshop draft or external reviews draft materials are also listed in Appendix C. 

D. APPROACH

Discussions will be held between NCEA/RTP staff and EPA workgroup members to help identify

key issues and approaches to addressing them. Non-EPA experts will also be consulted to help identify

and refine key issues to be addressed and pertinent new literature to be considered. Discussions will also

be held with the authors at the initial stages of document development to acquaint them with detailed

guidelines and specifications. Subsequent meetings with authors may be conducted to facilitate

continuity within and between chapters. Periodic coordination meetings will be held to facilitate flow of

information on document preparation progress, to obtain feedback on evolving draft materials, and to

determine any needed modifications in planned actions. 

The authors will be provided copies of the previous 1986 Lead AQCD/Addendum and the 1990

Supplement (U.S. Environmental Protection Agency, 1986). New sections for the updated document will

each first summarize key findings and conclusions from those prior document materials, including

reference to “key” studies. Once this background information is presented, the remainder of the given

section will be updated with discussion and interpretative evaluation of the newer literature. In cases

where no new information is available, the summarization of key findings from the previous criteria

document will suffice. The primary focus in the main Lead AQCD chapters will be on interpretive

evaluation of the most pertinent evidence with reference being made to more descriptive summarization

of details of particular studies provided in separate annexes to be appended to the main Lead AQCD.

A list of references published since the last review of lead criteria (mainly after completion of the

1986 Lead AQCD/Addendum and 1990 Supplement) will be made available to the authors. The

references will be selected from information data base searches conducted by EPA and from any materials

submitted in response to the November 2004 call for information. Hard copies of these references will be

supplied upon request. Additional references may need to be added to the list (e.g., missed or recently

published papers or “in press” publications). As an aid in selecting pertinent new literature, the authors

will also be provided with a summary of issues that need to be addressed in the preparation of the revised

Lead AQCD. These will include issues identified by authors and reviewers of the previous lead

document materials, raised in public discussions, workshops, or CASAC comments received by EPA

and/or raised via interactions involving EPA Lead Workgroup members. The list of issues may be further

augmented in the course of preparation or review of draft materials for the revised Lead AQCD. 
January 2005 DRAFT – DO NOT QUOTE OR CITE 18

E. PUBLIC AND SCIENTIFIC REVIEW

1. Review and Revision of Consultative Review Workshop Draft

When working drafts of the main chapters (other than the Executive Summary) of the document

have been completed by the authors, one or more workshops will be convened by the NCEA-RTP Project

Team. The workshops will include the document authors, EPA Work Group participants, and external

reviewers chosen on the basis of scientific expertise within specific areas covered. The workshops will be

open to the public, as announced in a Federal Register Notice.

2. Public Review of External Review Drafts

After the workshop consultative review process is completed, the authors, contributing reviewers,

and NCEA-RTP Project Team will resolve how to address comments received and will revise the draft

chapters in preparation for their inclusion in the First External Review Draft (ERD) of the Lead AQCD. 

After clearance by the U.S. EPA, the draft document will be released for public comment as announced in

a Federal Register Notice. Electronic and printed copies of the ERD will be made available for review

during a specified time period, usually of 60 to 90 days; written comments are solicited during this time. 

A similar procedure will be followed for public and CASAC review of a Second External Review Draft

that EPA expects to be necessary before completion of the Final Lead AQCD. 

3. Review by Clean Air Scientific Advisory Committee

At the time the First External Review Draft is released to the public, that draft document will also

be sent to the Clean Air Scientific Advisory Committee (CASAC) of EPA’s Science Advisory Board

(SAB). CASAC members and consultants (see Appendix D) will review the draft document and discuss

their comments in a public meeting announced in the Federal Register. At the meeting, the NCEA-RTP

Project Team plans to present an overview of the main features of the document, a summary of key issues

raised by public comments received on the document, and the charge to the committee, as well as being

prepared to discuss proposed revisions, if indicated. Based on CASAC’s past practice, EPA expects that

key CASAC advice and recommendations for revision of the document will be summarized by the

CASAC Chair in a letter to the EPA Administrator. EPA will take into account any such

recommendations, as well as CASAC and public comments at the meeting and any written comments

received, in revising the draft Lead AQCD. As noted earlier, EPA expects that it will be necessary to

prepare a Second External Review Draft for further CASAC review and public comment. After

appropriate revision, the final document will be made available on an EPA website and subsequently

printed, with its public availability being announced in the Federal Register. 
January 2005 DRAFT – DO NOT QUOTE OR CITE 19

References

Federal Register. (2004) Air quality Criteria Document for Lead: Call for Information. F. R.

(November 9) 69: 64926-64928.

Federal Register. (1979) National primary and secondary ambient air quality standards: revisions to

the National Ambient Air Quality Standards for lead. F. R. (February 8) 44: 8202-8237.

U.S. Environmental Protection Agency. (1986) Air quality criteria for lead. Research Triangle Park, NC:

Office of Health and Environmental Assessment, Environmental Criteria and Assessment Office;

EPA report nos. EPA/600/8-83/028A-F. Available from NTIS, Springfield, VA; PB87-142949.

U.S. Environmental Protection Agency. (1990) Summary of selected new information on effects of lead

on health and supplement to 1986 air quality criteria for lead. Research Triangle Park, NC: Office

of Health and Environmental Assessment, Environmental Criteria and Assessment Office; EPA

report no. EPA/600/8-89. Available from NTIS, Springfield, VA; PB92-235670.

U.S. Environmental Protection Agency. (2000) Science policy council peer review handbook. 2nd ed.

Washington, DC: Science Policy Council; report; EPA no. EPA-100-B-00-001.
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APPENDIX A

PROPOSED CONTENTS OF REVISED AIR QUALITY CRITERIA FOR LEAD

Page

LIST OF TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

LIST OF FIGURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

AUTHORS, CONTRIBUTORS, AND REVIEWERS .........................................

EXECUTIVE SUMMARY AND CONCLUSIONS ...........................................

1. INTRODUCTION .................................................................

1.1 LEGISLATIVE BACKGROUND ...............................................

1.2 REGULATORY BACKGROUND ..............................................

1.3 DOCUMENT PREPARATION AND REVIEW PROCESS ...........................

1.4 ORGANIZATION AND CONTENT OF THE DOCUMENT .........................

2. CHEMISTRY/PHYSICAL PROPERTIES OF LEAD AND MEASUREMENT METHODS ......

2.1 GENERAL CHEMISTRY OF LEAD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.2 ORGANOMETALLIC CHEMISTRY OF LEAD ...................................

2.3 STABLE ISOTOPE METHODOLOGIES ........................................

2.4 CONTAMINATION CONTROL METHODS .....................................

2.5 AIR SAMPLING MEASUREMENT/METHODOLOGIES ...........................

2.6 PARTICLE DEPOSITION MEASUREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.7 DUST SAMPLING METHODS FOR HUMAN EXPOSURE .........................

2.8 BIOLOGICAL TISSUE MEASUREMENT METHODS .............................

3. SOURCES, EMISSIONS, TRANSPORT, AND DEPOSITION .............................

3.1 SOURCES AND EMISSIONS OF ATMOSPHERIC LEAD ..........................

3.2 ATMOSPHERIC TRANSPORT AND DEPOSITION OF LEAD ......................

3.3 OTHER SOURCES OF LEAD IN DUST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4. ENVIRONMENTAL CONCENTRATIONS AND PATHWAYS TO HUMAN EXPOSURE .....

4.1 LEAD IN INHALED AIR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4.2 LEAD IN INGESTED DUST ..................................................

4.3 LEAD IN FOOD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4.4 LEAD IN DRINKING WATER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4.5 OTHER MISCELLANEOUS EXPOSURE PATHWAYS . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5. MODELS OF HUMAN EXPOSURE THAT PREDICT TISSUE DISTRIBUTION OF LEAD .....

5.1 HISTORIC LEAD MODELS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5.2 INTEGRATIVE EXPOSURE UPTAKE BIOKINETIC (IEUBK) MODEL 

FOR LEAD IN CHILDREN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5.3 ALL AGES LEAD MODEL (AALM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5.4 OTHER MODELING APPROACHES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6. TOXICOLOGICAL EFFECTS OF LEAD IN LABORATORY ANIMALS ....................

6.1 INTRODUCTION ...........................................................

6.2 EFFECTS ON HEME SYNTHESIS .............................................

6.3 NEUROLOGICAL/NEUROBEHAVIORAL EFFECTS ..............................

6.4 REPRODUCTIVE AND DEVELOPMENTAL EFFECTS ............................
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PROPOSED CONTENTS

(cont’d)

Page

6.5 CARDIOVASCULAR EFFECTS ...............................................

6.6 GENOTOXIC/CARCINOGENIC EFFECTS ......................................

6.7 SUMMARY AND CONCLUSIONS .............................................

REFERENCES ...................................................................

7. EPIDEMIOLOGIC STUDIES OF AMBIENT LEAD EXPOSURE EFFECTS ..................

7.1 INTRODUCTION ...........................................................

7.2 EFFECTS OF SHORT-TERM AMBIENT LEAD EXPOSURE

7.3 EFFECTS OF LONG-TERM AMBIENT LEAD EXPOSURE .........................

7.4 SUMMARY AND CONCLUSIONS .............................................

REFERENCES ...................................................................

8. INTEGRATIVE SYNTHESIS OF HUMAN LEAD EXPOSURE PATHWAYS AND 

HEALTH RISKS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

8.1 INTRODUCTION ...........................................................

8.2 SOURCES, CONCENTRATIONS, AND EXPOSURE PATHWAYS ...................

8.3 EVALUATION OF HEALTH RISKS FROM SHORT-TERM OR EPISODIC

LEAD EXPOSURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

8.3.1 Health Effects in the General Human Population .............................

8.3.2 Health Effects in Susceptible Population Groups .............................

8.4 HEALTH RISKS FROM LONG-TERM LEAD EXPOSURE .........................

8.4.1 Effects Associated With Chronic Exposures in Human Populations ..............

8.4.2 Extrapolation of Effects Observed in Laboratory Animals to 

Human Populations ....................................................

8.5 SUMMARY OF KEY FINDINGS AND CONCLUSIONS ...........................

REFERENCES ...................................................................

9. ENVIRONMENTAL EFFECTS OF LEAD .............................................

9.1 TERRESTRIAL ECOSYSTEMS ................................................

9.1.1 Introduction ..........................................................

9.1.2 Methodologies Used in Terrestrial Ecosystems Research .......................

9.1.3 Species Response/Mode of Action . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9.1.4 Factors that Modify Organisms Response to Lead . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9.1.5 Exposure/Response of Terrestrial Species ..................................

9.1.6 Effects of Lead on Natural Terrestrial Ecosystems . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9.1.7 Economic Effects of Lead on Agriculture, Forestry, and other 

Terrestrial Ecosystems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9.2 AQUATIC ECOSYSTEMS ....................................................

9.2.1 Introduction ..........................................................

9.2.2 Methodologies Used in Aquatic Ecosystems Research .........................

9.2.3 Species Response/Mode of Action . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9.2.4 Factors that Modify Organisms Response to Lead . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9.2.5 Exposure/Response of Aquatic Species ....................................

9.2.6 Effects of Lead on Natural Aquatic Ecosystems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9.2.7 Economic Effects of Lead on Aquaculture, Shellfishery, and Fishery Systems ......
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PROPOSED CONTENTS

(cont’d)

Page

9.3 EFFECTS OF LEAD ON NONBIOLOGICAL MATERIALS .........................

9.4 EFFECTS OF LEAD ON GLOBAL CLIMATE CHANGE PROCESSES ................

9.5 SUMMARY AND CONCLUSIONS .............................................

REFERENCES ..............................................................

APPENDIX: GLOSSARY OF TERMS AND SYMBOLS ................................
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APPENDIX B

EPA WORK GROUP FOR AIR QUALITY CRITERIA FOR LEAD

Dr. William K. Boyes Toxicology

National Health and Environmental Effects Research Laboratory (B-105-05)

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711

Ms. Beverly M. Comfort Indoor air quality

National Center for Environmental Assessment (B-243-01)

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711

Dr. J. Michael Davis Toxicology

National Center for Environmental Assessment (B-243-01)

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711

Dr. Robin L. Dennis Atmospheric modeling

National Exposure Research Laboratory (E-243-01)

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711

Mr. Ronald Evans Economic assessment

Office of Air Quality Planning and Standards (C-339-01) consultation

U.S. Environmental Protection Agency

Research Triangle Park, N.C. 27711

Mr. William G. Ewald Environmental

National Center for Environmental Assessment (B-243-01) concentrations

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711

Mr. Tyler Fox Atmospheric modeling

Office of Air Quality Planning and Standards (D-243-01) consultation

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711

Dr. Mary E. Gilbert Toxicology

National Health and Environmental Effects Research Laboratory (B-105-05)

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711

Dr. Ian Gilmour Immunotoxicology

National Health and Environmental

 Effects Research Laboratory (MD-92)

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711
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EPA WORK GROUP

(cont’d)

Gerald Gleason Consultation

Office of General Counsel (2344A)

U.S. Environmental Protection Agency 

Washington, DC 20460

Dr. Lester D. Grant, Director Executive and

National Center for Environmental Assessment (B-243-01) technical oversight

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711

Dr. Sharon Harper Analytical methods 

National Exposure Research Laboratory (D-205-5) Exposure aspects

U.S. Environmental Protection Agency 

Research Triangle Park, NC 27711

Mr. James B. Hemby Air quality 

Office of Air Quality Planning and Standards (C-304-01) consultation

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711

Dr. Brooke Hemming Atmospheric science 

National Center for Environmental Assessment (B-243-01)

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711

Dr. Lee Hofmann Soil/Dust Pb

Office of Solid Waste and Emergency Response consultation

Office of Solid Waste (5103-T)

U.S. Environmental Protection Agency

EPA West Building

1200 Pennsylvania Avenue, N.W.

Washington, DC 20460

Dr. Ji Young Kim Epidemiology

National Center for Environmental Assessment (B-243-01)

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711

Dr. Dennis Kotchmar Epidemiology

National Center for Environmental Assessment (B-243-01)

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711

Dr. Charles W. Lewis Source apportionment

National Exposure Research Laboratory (E-205-03)

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711
January 2005 DRAFT – DO NOT QUOTE OR CITE B-3

EPA WORK GROUP

(cont’d)

Dr. Timothy E. Lewis Terrestrial and aquatic

National Center for Environmental Assessment (B-243-01) ecosystem effects

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711

Dr. Deborah J. Luecken Atmospheric chemistry

National Exposure Research Laboratory (E-205-02)

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711

Dr. Deborah Mangis Ecosystems; Exposure

National Exposure Research Laboratory (D-305-01)

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711

Dr. Karen M. Martin Consultation

Office of Air Quality Planning and Standards (C-539-01)

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711

Mr. Thomas R. McCurdy Exposure;

National Exposure Research Laboratory (E-205-02) Activity patterns

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711

Mr. David C. Misenheimer Air emissions

Office of Air Quality Planning and Standards (D-205-01) consultation

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711

Dr. Srikanth Nadadur Toxicology

National Center for Environmental Assessment (B-243-01)

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711

Dr. Lucas Neas Epidemiology;

National Health and Environmental Children’s health

 Effects Research Laboratory (MD-58)

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711

Ms. Sharon V. Nizich Air quality/trends

Office of Air Quality Planning and Standards (C-339-02) consultation

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711
January 2005 DRAFT – DO NOT QUOTE OR CITE B-4

EPA WORK GROUP

(cont’d)

Dr. Edward Ohanian Water Pb consultation

Office of Water (4304-T)

U.S. Environmental Protection Agency

EPA West Building

1200 Pennsylvania Avenue, N.W.

Washington, DC 20460

Dr. David Olszyk Crops

National Health and Environmental

 Effects Research Laboratory

U.S. Environmental Protection Agency

200 S.W. 35th Street

Corvallis, OR 97333

David Orlin Consultation

Air and Radiation Office of General Counsel (2344A)

U.S. Environmental Protection Agency 

Washington, DC 20460

Dr. Zackary Pekar Exposure/dosimetry

Office of Air Quality and Standards (6-339-01) consultation

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711

Dr. Joseph P. Pinto Air chemistry;

National Center for Environmental Assessment (B-243-01) Global effects

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711

Mr. Harvey M. Richmond Exposure modeling

Office of Air Quality Planning and Standards (C-539-01) consultation

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711

Dr. Mary Ross Human health

Office of Air Quality Planning and Standards (C-539-01) consultation

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711

Mr. William E. Russo Consultation

National Health and Environmental

 Effects Research Laboratory (B-305-02)

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711
January 2005 DRAFT – DO NOT QUOTE OR CITE B-5

EPA WORK GROUP

(cont’d)

Ms. Victoria A. Sandiford Ecosystems

Office of Air Quality Planning and Standards (C-539-01) consultation

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711

Mr. Kenneth L. Schere Atmospheric modeling

National Exposure Research Laboratory (E-243-03)

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711

Dr. Dave Topping Pb-based paint

Office of Prevention, Pesticides, and Toxic Substances (7404-T) consultation

U.S. Environmental Protection Agency

EPA West Building

1200 Pennsylvania Avenue, N.W.

Washington, DC 20460
January 2005 DRAFT – DO NOT QUOTE OR CITE C-1

APPENDIX C

NCEA-RTP PROJECT TEAM AND OTHER TECHNICAL CONSULTANTS

NCEA-RTP Project Team

Scientific Staff

Dr. James Brown — Health Scientist, National Center for Environmental Assessment (B-243-01),

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Ms. Beverly M. Comfort — Health Scientist, National Center for Environmental Assessment 

(B-243-01), U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Dr. J. Michael Davis — Senior Health Science Advisor, National Center for Environmental Assessment 

(B-243-01), U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Dr. Robert W. Elias — Senior Health Scientist, National Center for Environmental Assessment

(B-243-01), U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Mr. William G. Ewald — Health Scientist, National Center for Environmental Assessment (B-243-01),

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Dr. Brooke Hemming — Atmospheric Scientist, National Center for Environmental Assessment

(B-243-01), U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Dr. Ji Young Kim — Epidemiologist, National Center for Environmental Assessment (B-243-01),

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Dr. Timothy E. Lewis — Ecologist, National Center for Environmental Assessment (B-243-01), 

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Dr. Shrikanth Nadadur — Health Scientist, National Center for Environmental Assessment (B-243 01), 

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Dr. Joseph P. Pinto — Physical Scientist, National Center for Environmental Assessment (B-243-01), 

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Dr. Lori White — Health Scientist, National Center for Environmental Assessment 

(B-243-01), U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Technical Support Staff

Mr. Douglas B. Fennell — Technical Information Specialist, National Center for Environmental

Assessment (B-243-01), U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Ms. Emily R. Lee — Management Analyst, National Center for Environmental Assessment (B-243-01),

U.S. Environmental Protection Agency, Research Triangle Park,
January 2005 DRAFT – DO NOT QUOTE OR CITE C-2

NCEA-RTP PROJECT TEAM AND OTHER TECHNICAL CONSULTANTS

(cont’d)

Technical Support Staff (cont’d)

Ms. Diane H. Ray — Program Specialist, National Center for Environmental Assessment (B-243-01),

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Ms. Donna Wicker — Management Analyst, National Center for Environmental Assessment (B-243-

01), U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Other EPA Contributors

Dr. William K. Boyes — National Health and Environmental Effects Research Laboratory (B-105-05),

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Dr. Ian Gilmour — National Health and Environmental Effects Research Laboratory (B-143-04),

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Dr. Mary E. Gilbert — National Health and Environmental Effects Research Laboratory (B-105-05),

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Dr. Charles W. Lewis — National Exposure Research Laboratory (E-205-03), U.S. Environmental

Protection Agency, Research Triangle Park, NC 27711

Dr. Sharon Harper — National Exposure Research Laboratory (D-205-05), U.S. Environmental

Protection Agency, Research Triangle Park, NC 27711

Dr. Lucas Neas — National Health and Environmental Effects Research Laboratory (MD-82),

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Dr. David Olszyk — National Health and Environmental Effects Research Laboratory,

U.S. Environmental Protection Agency, 200 SW 35th Street, Corvallis, OR 97333

Dr. MaryJane K. Selgrade — National Health and Environmental Effects Research Laboratory

(B-143-04), U.S. Environmental Protection Agency, Research Triangle Park, NC 27711
1

This list of non-EPA scientists is proposed on the basis of published, peer-reviewed scientific publications on topic areas that are

likely to be included in the revised criteria document or on the basis of previous involvement as an author, contributor, or

reviewer of the 1986 Lead AQCD/Addendum. Contractual agreements for professional services would be the likely mechanism

for obtaining their contributions to the revised Air Quality Criteria Document for Lead and/or their participation in workshops.

January 2005 DRAFT – DO NOT QUOTE OR CITE C-3

NCEA-RTP PROJECT TEAM AND OTHER TECHNICAL CONSULTANTS

(cont’d)

Non-EPA Consultants (Potential Sources1)

Dr. Carol Angle — Toxicology/Epidemiology, University of Nebraska Medical Center

Dr. Ann Aschengrau — Toxicology/Epidemiology, Boston University

Dr. Gerald Audesirk — Toxicology/Epidemiology, University of Colorado

Dr. Donald Barltrop — Toxicology/Epidemiology, Westminister Children’s Hospital

Dr. Barbara Beck — Health Scientist, Gradient Corp

Dr. Mike Bolger — Health Scientist, FDA

Mr. Craig Borieko — Environmental Scientist, ILZRO

Dr. Robert Bornschein — Toxicology/Epidemiology, University of Cincinnati

Dr. Mary Jean Brown — Health Scientist, CDC

Dr. Ian Calder — Health Scientist, South Australian Health Commission

Dr. Rufus Chaney — Environmental Scientist, USDA

Dr. Deborah Cory-Slechta — Toxicology/Epidemiology, Rutgers

Dr. Anita Curren — Toxicology/Epidemiology, Westchester County Health Department

Dr. Cliff Davidson — Environmental Scientist, Carnegie-Mellon University

Dr. Gary Diamond — Statistician, Syracuse Research Corp

Dr. Kim Dietrich — Health Scientist, University of Cincinnati

Dr. Mark Farfel — Toxicology/Epidemiology, Kennedy-Krieger Institute

Dr. Russ Flegal — Environmental Scientist, University of California, Santa Cruz

Dr. Bruce Fowler — Toxicology/Epidemiology, University of Maryland

Dr. Don Fox — Toxicology/Epidemiology, University of Houston

Dr. Tom Goehl — Toxicology/Epidemiology, NIEHS
January 2005 DRAFT – DO NOT QUOTE OR CITE C-4

NCEA-RTP PROJECT TEAM AND OTHER TECHNICAL CONSULTANTS

(cont’d)

Non-EPA Consultants (Potential Sources1) (cont’d)

Dr. Phil Goodrum — Statistician, Syracuse Research Corporation

Dr. Robert Goyer — Toxicology/Epidemiology, Retired, Chapel Hill, NC 

Dr. Brian Gulson — Health Scientist, Macquarie University, Sidney Australia

Dr. Vic Hasselblad — Statistician, Duke University

Dr. Derek Hodgson — Toxicology/Epidemiology, University of North Carolina

Mr. Dave Jacobs — Environmental Engineer, HUD

Dr. Richard Kaufman — Health Scientist, ATSDR

Dr. David Koeppe — Texas Tech University

Dr. Phil Landrigan — Toxicology/Epidemiology

Dr. Bruce Lanphear — Toxicology/Epidemiology, Children’s Hospital Medical Center, Cincinnati, OH

Dr. Stephen Lasley — Toxicology/Epidemiology, University of Illinois

Dr. Samuel Lestz — Pennsylvania State University

Dr. Morton Lippmann — Toxicology/Epidemiology, New York University Medical Center

Dr. Ben Liu — Atmospheric Scientist, University of Minnesota

Dr. Paul Mushak — Toxicology/Epidemiology, PB Associates, Durham, NC

Dr. Herbert Needleman — Toxicology/Epidemiology, Children’s Hospital of Pittsburgh

Dr. Jerome Nriagu — Environmental Scientist, University of Michigan

Dr. Ellen O’Flaherty — Toxicology/Epidemiology, Retired

Dr. Anna Orlova — Toxicology/Epidemiology, John Hopkins School of Hygiene & Public Health

Dr. Dan Paschal — Environmental Chemist, CDC

Dr. Joel Pounds — Toxicology/Epidemiology, Battelle Pacific Northwest

Dr. Michael Rabinowitz — Environmental Scientist, Children’s Hospital Medical Center

Dr. Deborah Rice — Toxicology/Epidemiology, State of Maine
January 2005 DRAFT – DO NOT QUOTE OR CITE C-5

NCEA-RTP PROJECT TEAM AND OTHER TECHNICAL CONSULTANTS

(cont’d)

Non-EPA Consultants (Potential Sources1) (cont’d) 

Dr. John Rosen — Toxicology/Epidemiology, Albert Einstein College of Medicine

Dr. Glen Sanderson — Environmental Scientist, Illinois Natural History Survey

Dr. Ellen Silbergeld — Toxicology/Epidemiology, University of Maryland

Dr. Don Smith — Environmental Scientist, University of California, Santa Cruz

Dr. William Smith — Ecologist, Yale University, School of Forestry

Dr. Paul Succop — Statistician, University of Cincinnati Medical Center

Mr. Ian von Lindern — Environmental Scientist, TerraGraphics

Mr. Brian Wilson — Environmental Scientist, ILZRO

Dr. Nasser Zawia — Toxicology/Epidemiology, University of Rhode Island
January 2005 DRAFT – DO NOT QUOTE OR CITE D-1

APPENDIX D

U.S. EPA SCIENCE ADVISORY BOARD 

CLEAN AIR SCIENTIFIC ADVISORY COMMITTEE MEMBERS

Fiscal Year 2005

The Clean Air Scientific Advisory Committee (CASAC) has a statutorily mandated responsibility

to review and offer scientific and technical advice to the Administrator on the air quality criteria and

regulatory documents that form the basis for the national ambient air quality standards (NAAQS), which

currently include standards for lead (Pb), particulate matter (PM), ozone (O3), and other photochemical

oxidants, carbon monoxide (CO), nitrogen oxides (NOx) and sulfur oxides (SOx). To perform such

reviews, in each case the Committee forms a review panel consisting of CASAC members and augmented

by selected consultants with expertise in scientific or technical areas pertinent to the given pollutant or

pollutant class under review. 

CHAIR

Dr. Rogene Henderson

Lovelace Respiratory Symposium

Lovelace Respiratory Research Institute

Albequerque, NM 87185 

PAST CHAIR

Dr. Philip Hopke

Robert A. Plane Professor

Department of Chemical Engineering

Clarkson University 

Potsdam, NY 13699

MEMBERS

Dr. Frederick Miller

Director of Respiratory Toxicology Research

Chemical Industry Institute of Toxicology

Research Triangle Park, NC 27709 

Mr. Richard Poirot

Environmental Analyst

Department of Environmental Conservation

Vermont Agency of Natural Resources

Waterbury, VT 05671

Dr. Frank Speizer

Edward Kass Professor of Medicine

Channing Laboratory

Harvard Medical School

Boston, MA 02115
January 2005 DRAFT – DO NOT QUOTE OR CITE D-2

SCIENCE ADVISORY BOARD

(cont’d)

MEMBERS

(cont’d)

Dr. Ellis B. Cowling

University Distinguished Professor

North Carolina State University

Raleigh NC

Dr. James Crapo

Chairman, Dept. of Medicine

National Jewish Medical and Research Center

Denver, CO

Dr. Barbara Zielinska

Research Professor

Atmospheric Sciences Division

Desert Research Institute

Reno, NV 89512

SCIENCE ADVISORY BOARD STAFF

Mr. Fred A. Butterfield, III

Designated Federal Officer

Clean Air Scientific Advisory Committee

Science Advisory Board (1400A) 

US Environmental Protection Agency

Washington, DC 20460

Ms. Zisa Lubarov-Walton

Management Assistant

Science Advisory Board (1400A) 

US Environmental Protection Agency

Washington, DC 20460
Office of Research and Development

National Center for Environmental Assessment

Research Triangle Park, NC 27711

Official Business

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January 2005

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