SUMMARY REPORT
HAIR ANALYSIS PANEL DISCUSSION:
EXPLORING THE STATE OF THE SCIENCE
June 12–13, 2001
Prepared for:
The Agency for Toxic Substances and Disease Registry
Division of Health Assessment and Consultation
and
Division of Health Education and Promotion
Atlanta, Georgia
Prepared by:
Eastern Research Group
110 Hartwell Avenue
Lexington, MA 02421
December 2001
ATSDR Hair Analysis Panel Discussion
NOTE
This report was prepared by Eastern Research Group, Inc. (ERG), an ATSDR contractor, as a
general record of discussion for the “ATSDR Hair Analysis Panel Discussion: Exploring the State
of the Science.” As requested by ATSDR, this report captures the main points of scheduled
presentations and highlights discussions among the panelists. This report is not a verbatim
transcript of the meeting proceedings, nor does it embellish, interpret, or expand upon matters or
agenda topics that were incomplete, unclear, or not addressed. Statements are the individual
views of each panelist or meeting participant. Except as specifically noted, no statements in this
report represent analyses or positions of ATSDR or ERG.
Any mention of trade names or commercial products does not constitute endorsement or
recommendation for use by ATSDR or the Department of Health and Human Services.
ATSDR Hair Analysis Panel Discussion
FOREWORD
The Agency for Toxic Substances and Disease Registry (ATSDR) has found the expert panel
process to be an effective tool for discussing and weighing scientific and public health issues.
ATSDR convened one such expert panel to discuss the state of the science related to analyzing
hair for environmental substances of concern found at hazardous waste sites. The panel consisted
of individuals who represented state and federal government agencies, academia, and private
practice and whose expertise, interests, and experience covered a wide range of technical
disciplines that were critical to the issues being discussed. ATSDR convened the expert panel as
part of an effort to begin formulating guidance on the use of hair analysis in exposure
assessments. The panel met to discuss their opinions regarding hair analysis for 1½ days in June
2001 in Atlanta, Georgia. This document summarizes the panel discussions.
For ATSDR, the overarching objective of the panel discussion was to gain information on when
to consider using hair analysis for exposure assessments. Exposure assessments are a necessary
component of public health assessments and other related public health activities performed by the
Agency for communities near hazardous waste sites. The Agency sought information about the
overall utility, advantages, and limitations of hair analysis and how these factors would affect
informed decisions on a site-specific basis.
The panel was asked to address a series of general questions about the science of hair analysis.
These focused on exposure assessment and health interpretation of the results of hair analysis. The
panel was strongly encouraged to avoid discussing the merits of hair analysis for drug testing or
nutritional screening, unless such discussions involved a technical point that was directly
applicable to environmental exposure assessment at hazardous waste sites. ATSDR did not seek
consensus statements from the panel; rather, the panel was asked to discuss in detail specific
issues related to methodology, factors influencing the interpretation of results, toxicologic
considerations, data gaps, and research needs. The opinions expressed in the report are those of
the individual panelists and may or may not represent those of ATSDR.
ATSDR views the panel discussions as a first step to sorting through the scientific issues
regarding the advantages and disadvantages of hair analysis. ATSDR plans to weigh the
information and data presented at the panel meeting and, over the next few months, develop
interim guidance for its health assessors and other professionals who are asked by communities
about the virtues of hair analysis as it relates to exposure and health evaluations at hazardous
waste sites.
RADM Robert C. Williams, P.E., DEE
Assistant Surgeon General
U.S. Public Health Service
and
Director, Division of Health Assessment and Consultation (DHAC)
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Agency for Toxic Substances and Disease Registry
TABLE OF CONTENTS
LIST OF ABBREVIATIONS ................................................. iii
EXECUTIVE SUMMARY .................................................... v
SECTION 1
INTRODUCTION ................................................... 1-1
1.1 Background .................................................. 1-1
1.2 Selection of Panelists ........................................... 1-3
1.3 Charge to the Panelists .......................................... 1-4
1.4 The Meeting Format ............................................ 1-5
1.5 The Report Organization ........................................ 1-6
SECTION 2
OPENING REMARKS AND PRESENTATIONS ........................... 2-1
2.1 Welcome .................................................... 2-1
2.2 Purpose of the Meeting and Charge to the Panelists .................... 2-2
2.3 Impetus for Panel Discussions—A Case Example ...................... 2-6
2.4 General Physiology of Hair—An Overview ........................... 2-8
SECTION 3
SAMPLING AND ANALYTICAL METHODS ............................ 3-1
3.1 Sample Collection Methods ...................................... 3-2
3.2 Sample Preparation Methods ..................................... 3-3
3.3 Analytical Methods ............................................. 3-4
SECTION 4
FACTORS INFLUENCING THE INTERPRETATION OFANALYTICAL
RESULTS ......................................................... 4-1
4.1 Distinguishing Between Endogenous and Exogenous Sources of Metals ..... 4-1
4.2 Temporal Considerations and Exposure Conditions .................... 4-4
4.3 Reference/Background Ranges .................................... 4-5
SECTION 5
TOXICOLOGIC CONSIDERATIONS ................................... 5-1
5.1 Pharmacokinetic Issues .......................................... 5-2
5.2 Dose-Response and Clinical Relevance .............................. 5-3
5.3 Choosing the Best Biological Marker ............................... 5-5
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SECTION 6
CONCLUSIONS AND RECOMMENDATIONS ........................... 6-1
6.1 What is the State of the Science of Hair Analysis? ...................... 6-1
6.2 When Is It Appropriate to Consider Hair Analysis in Assessing Human
Exposures to Environmental Contaminants? .......................... 6-1
6.3 What Are the Limitations of Hair Analysis? What Data Gaps and
Research Needs Exist? .......................................... 6-3
6.4 Recommendations ............................................. 6-5
6.5 Next Steps to be Taken by ATSDR ................................ 6-6
SECTION 7
OBSERVER COMMENTS ............................................ 7-1
SECTION 8
REFERENCES ..................................................... 8-1
Appendices
Appendix A List of Panelists and Panelist Biographical Sketches
Appendix B Charge to the Panel
Appendix C Pre-Meeting Comments
Appendix D Hair Analysis Bibliography
Appendix E Meeting Agenda
Appendix F List of Observers
Appendix G Post-Meeting Observer Comments
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LIST OF ABBREVIATIONS
AA atomic absorption
ATSDR Agency for Toxic Substances and Disease Registry
CDC Centers for Disease Control and Prevention
CLIA Clinical Laboratory Improvement Act
DHAC Division of Health Assessment and Consultation
DHEP Division of Health Education and Promotion
EI exposure investigation
EPA U.S. Environmental Protection Agency
HIV human immunodeficiency virus
IARC International Agency for Research on Cancer
ICP-AES Inductively coupled argon plasma atomic emission spectrometry
ICP-MS Inductively coupled argon plasma mass spectrometry
ICP-OES Inductively coupled argon plasma optical emission spectrometry
?g/L micrograms per liter
NAA Neutron activation analysis
NHANES National Health and Nutrition Examination Survey
NRC National Research Council
NTP National Toxicology Program
PIXE Proton induced x-ray emission
ppm parts per million
PTH parathyroid hormone
QA/QC quality assurance/quality control
Abbreviations for Panelists’ Names
RB Dr. Robert Baratz
TC Dr. Thomas Clarkson
MG Dr. Michael Greenberg
MK Dr. Michael Kosnett
DP Dr. Dan Paschal
SS Dr. Sharon Seidel
LW Dr. LuAnn White
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EXECUTIVE SUMMARY
The Agency for Toxic Substances and Disease Registry (ATSDR) convened a seven-member
panel to review and discuss the current state of the science related to hair analysis, specifically its
use in assessing environmental exposures. ATSDR invited a cross section of scientific experts in
the fields of hair analysis, toxicology, and medicine to participate in 1½ days of discussions on a
variety of topics, including analytical methods, factors affecting the interpretation of analytical
results, toxicologic considerations, and data gaps/research needs. The meeting was held June 12
and 13, 2001, in Atlanta, Georgia.
Background
ATSDR convened this panel in response to (1) a growing number of inquiries from community
members looking for assistance in interpreting hair analysis results and (2) agency interest in
learning more about the utility of hair analysis in evaluating exposures and health effects at
hazardous waste sites. The agency hopes to use the input received from this effort to develop
guidance for agency health assessors on the use and interpretation of hair analysis data.
The general questions that ATSDR seeks to answer include:
• For what substances do reliable hair analysis methods exist?
• When is it appropriate/inappropriate to consider hair analysis in assessing human
exposures to environmental contamination?
• What data gaps exist that limit the interpretation and use of hair analysis in the
assessment of environmental contaminants?
This summary report presents the findings of the panel discussions. Central discussion points are
highlighted below.
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Overview of Discussions
Panelists engaged in a series of discussions to address ATSDR’s questions, pointing to several
limitations—having to do with the current state of the knowledge—on the usefulness of hair
analysis in assessments of environmental exposures. Discussions focused primarily on metals and
trace elements in scalp hair. Panelists considered the distinct differences between using hair
analysis to identify exposures (Is the substance reaching people? Does a competed pathway
exist?) and using it to predict, diagnose, or treat disease (What do hair concentrations tell us
about the likelihood of harmful health effects?). Panelists noted that the latter is where the largest
data gaps exist.
Although they were not required to reach consensus, the panelists did agree on the following
summary statement related to the overall usefulness of hair analysis in evaluating environmental
exposures:
For most substances, insufficient data currently exist that would allow the prediction of a
health effect from the concentration of the substance in hair. The presence of a substance
in hair may indicate exposure (both internal and external), but does not necessarily indicate
the source of exposure.
For what substances do reliable hair analysis methods exist?
The group agreed that laboratory methods exist to measure the levels of some environmental
contaminants in hair, but procedures need to be standardized to help ensure more accurate and
reliable results (this includes ensuring that samples are collected by a trained person and
establishing consistent sampling protocols, washing protocols, quality control/quality assurance
procedures, etc.). Further, the panel agreed that testing should be targeted to the specific element
of interest.
ATSDR Hair Analysis Panel Discussion
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When is it appropriate/inappropriate to consider hair analysis in assessing human exposures to
environmental contamination?
In general, panelists agreed that, before determining the appropriateness of hair analysis as an
assessment tool, assessors should consider the following:
(1) The exposure type and period. Take exposure histories to understand the likelihood that a
particular substance will be in the hair at the time of testing and to identify other exposure
sources (e.g., hair treatments).
Because the growth rate of hair is on average 12 centimeters per year, the panel concluded
that hair analysis is not generally useful for evaluating very recent exposures or those
longer ago than 1 year. Segmental analysis of hair (i.e., looking at concentration trends
along the length of the hair) may have a role in documenting exposures over time (e.g.,
identification of a high-dose acute exposure). This would need to be considered on a
subject-, substance-, and situation-specific basis.
(2) The type of substance and its behavior in the body. Determine the biological plausibility
that a particular substance will be present in hair and whether it is a marker of external
contamination.
The group agreed that little is known about the transfer kinetics of substances into hair.
(3) The clinical relevance of a negative or positive finding. Determine whether any dose-
response relationship exists between chemical concentrations in hair and target organ
effects/illness. Without an understanding of a dose-response relationship, useful
interpretations will not be possible.
The panelists agreed that a relationship between contaminant concentrations in hair and
any kind of measurable outcome have only been established for methyl mercury (e.g., the
relation between maternal hair levels and observed developmental neurological
abnormalities in offspring) and to a limited extent for arsenic (e.g., segmental analysis for
forensic analysis), provided external contamination can be ruled out. There may be unique
forensic settings for other substances.
The group also indicated the need to evaluate, on a substance- and exposure-specific basis, the
extent to which hair analysis may be more advantageous than other biological sampling, such as
blood or urine analysis.
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What data gaps exist that limit the interpretation and use of hair analysis in the assessment of
environmental contaminants?
The group identified several factors that limit the interpretation of even the most accurate,
reliable, and reproducible laboratory results. These include:
• The lack of reference (or background) ranges in which to frame the interpretation of
results. Assessors need a greater understanding of what is expected to be in hair in the
absence of environmental exposures in order to determine whether detected levels are
elevated as a result of environmental releases, including possible geographical or regional
differences in background levels.
• Difficulties in distinguishing endogenous (internal) from exogenous (external)
contamination in hair. Being able to make this distinction is important in evaluating
internal doses of the substance of interest. The group voiced different views on the
effectiveness of washing hair prior to analysis to eliminate external contamination. Some
felt that the current literature suggests that there is no reliable washing method capable of
separating external contamination from internal deposition of elements. It was suggested
that identifying metabolites (or other unique markers of internal exposure) for substances
of interest, where possible, is most helpful in distinguishing internal from external
contamination.
• A lack of understanding of how and to what extent environmental contaminants are
incorporated into the hair. Little scientific information is available on the uptake or
incorporation of environmental contaminants into hair. Neither kinetic models nor
metabolite data are known or fully understood for metals or environmentally relevant
organic compounds.
• The lack of correlation between levels in hair and blood and other target tissues, as well
as the lack of epidemiologic data linking substance-specific hair levels with adverse
health effects. These correlations must be understood before hair analysis results can be
used as a diagnostic tool or to predict health endpoints. The panel noted that hair analysis
is not likely to play a role in evaluations of some of the more common health concerns
associated with hazardous waste sites (e.g., cancer, birth defects).
• Little information is available pertinent to the study of environmentally relevant organic
compounds in hair. The panel recommended taking advantage of what is known about
hair analysis for testing drugs of abuse.
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In moving forward, the panelists encouraged the standardization of sampling protocols and
identified possible research areas. Before hair analysis can be considered a valid tool for any
particular substance, research is needed to establish better reference ranges, gain a better
understanding of hair biology and pharmacokinetics, further explore possible dose-response
relationships, establish whether and when hair may serve as a better measure or predictor of
disease than other biological samples (e.g., blood or urine), and learn more about organic
compounds in hair.
Future ATSDR Activities
ATSDR plans to evaluate all the input received during the panel deliberations and generate a
report on lessons learned from the panel discussions. In addition, the agency anticipates that the
following activities will help all of ATSDR’s divisions as well as professionals in the community.
• Providing education to physicians and other health professionals about hair analysis.
• Developing a generic fact sheet to help health assessors and communities communicate
and understand hair analysis issues.
• Continuing to develop substance-specific toxicological profiles. The profiles are an
excellent resource and contain information on biomarkers of exposure. In light of the
panel discussions, additional language may be added regarding hair analysis (e.g., in terms
of limitations, etc.).
• Developing guidance on hair analysis to support public health assessments and health
studies conducted by the agency. That is, developing criteria for determining when to
consider hair analysis as part of an ATSDR exposure investigation.
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SECTION 1
INTRODUCTION
ATSDR convened a panel of seven experts to discuss the state of the science related to hair
analysis, with specific focus on its utility in assessing environmental exposures. A 1½-day meeting
held at the Radisson Executive Park in Atlanta, Georgia, on June 12 and 13, 2001, served as a
forum for the panelists to discuss scientific issues related to the analysis and interpretation of hair
data. The meeting, which was open to the public, also gave other interested parties the
opportunity to observe the discussions, ask questions, and provide input.
This section details ATSDR’s purpose for convening the panel (Section 1.1), how ATSDR
selected panel members (Section 1.2), the charge to the panel (see Section 1.3), the meeting
format (see Section 1.4), and the organization of this summary report (see Section 1.5).
1.1 Background
ATSDR conducts public health assessments to evaluate possible public health implications of
contamination associated with hazardous waste sites and other environmental releases. An
important step in ATSDR’s assessment process is examining exposures to contaminants under
site-specific conditions and determining whether people are being exposed to contaminants at
harmful levels. In most of the agency’s evaluations, the environmental concentration serves as a
surrogate for “exposure.”
Exposure concentrations, or estimated doses based on exposure concentrations, however,
represent only one factor in a continuum of events that ultimately determine whether exposures
will result in illness. Other factors include exposure conditions and various
pharmacokinetic/pharmacodynamic events (e.g., absorption, distribution, metabolism, excretion),
ATSDR Hair Analysis Panel Discussion
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as well as individual variability and susceptibility in the exposed population. To a large extent,
ATSDR evaluates these factors qualitatively in its public health assessments.
To refine its assessments and/or to fill data gaps, ATSDR seeks ways to more precisely quantify
exposures, such as measuring body burdens of a particular contaminant or its metabolites (e.g.,
lead in blood or arsenic and its metabolites in urine). On a site-by-site basis, ATSDR evaluates
what additional exposure data it might be practical and useful to obtain to further support public
health evaluations and ultimately to help determine the disease potential of a particular exposure.
In convening this panel, ATSDR’s goal was to determine the overall utility of hair analysis as one
such exposure assessment tool. Hearing various points of view will help ATSDR draw
conclusions based on the best available science.
ATSDR plans to weigh the information and data presented at the panel meeting and, in the short
term (i.e., over the next several months), independently develop some interim guidance for its
health assessors and others at ATSDR who are asked by communities about the virtues of hair
analysis in understanding exposures to, or the disease potential of, particular chemicals. For the
purposes of the panel discussions, ATSDR was not seeking consensus of the panel on any
particular issue, but rather scientific input (consistent or varied) for consideration by the agency.
Also, the panel was not convened to discuss or evaluate the merits of hair analysis for other
purposes (e.g., testing for drugs of abuse or nutritional screening). Again, the focus was on
environmental exposures.
See the introductory remarks in Section 2 for additional background information.
ATSDR Hair Analysis Panel Discussion
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1.2 Selection of Panelists
ATSDR identified candidates for the expert panel by reviewing the scientific literature in the field
of hair analysis, researching professional organizations, and consulting with known experts within
research institutes and other academic centers. The agency sought individuals who were
experienced in the field of hair analysis and its interpretation for hazardous substances released to
the environment.
To help ensure that a broad range of views was brought to the table, the agency sought
individuals possessing a range of experience, interest, and expertise in the field of hair analysis.
Potential candidates were ranked based on their level of technical expertise (i.e., either high,
medium, or low) in each of the following categories:
• Hair analysis research
• Laboratory analysis
• Pediatric medicine
• Occupational medicine
• Forensic medicine
• Exposure assessment
Based on these criteria, ATSDR selected seven panelists, each of whom had expertise in one or
more of the categories listed above. The collective expertise of the panel covered all categories,
and individuals on the panel represented state and federal government, academia, and private
practice.
ATSDR Hair Analysis Panel Discussion
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The papers provided to the panelists for their consideration included: Hopps 1977; Miekeley et al.
1998; Sky-Peck 1990; Seidel et al. 2001; Steindel and Howanitz 2001 (editorial); Yoshinaga et al. 1990;
Wennig 2000.
1-4
Appendix A lists the names and affiliations of the panelists who participated in the meeting as well
as a brief biographical sketch of each of the panelists.
1.3 Charge to the Panelists
ATSDR prepared a list of specific questions for the panel (referred to as the “charge”). Questions
included a wide variety of topics designed to prompt discussions at the meeting. The main topics
in the charge include:
• Analytical methodologies
• Factors influencing the interpretation of analytical results
• Toxicologic considerations
• Data gaps and research needs
• Identifying scenarios for which hair analysis may be appropriate
A copy of the charge to the panelists is included in this report as Appendix B.
Prior to the June 12 and 13, 2001, meeting, panelists were requested to review the charge and
prepare initial responses to the charge questions (in the form of pre-meeting comments). To
support their effort, panelists received six papers from the published literature and a bibliography
of additional literature pertaining to hair analysis.
1
The purpose of this pre-meeting exercise was
to stimulate panelists’ thoughts in relation to the charge questions and to serve as a stepping-off
point for the 1½ days of panel discussions. Appendix C contains the panelists’ pre-meeting
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comments.
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Panelists provided additional relevant references with their pre-meeting comments and during
panel discussions. An expanded bibliography of hair analysis literature is provided in
Appendix D.
1.4 The Meeting Format
After some introductory remarks by ATSDR and an overview of hair physiology by one of the
panelists, the panel engaged in open discussions related to individual charge questions.
Discussions generally followed the meeting agenda, as shown in Appendix E. However, as might
be expected, some overlap occurred across topics due to the closely linked nature of the topics.
Dr. LuAnn White led the panel discussions. At the beginning of the meeting, she clearly stated the
ground rules for the discussion:
• Focus on the scientific issues related to hair analysis.
• Focus on the specific charge topics. In the context of the charge questions, describe the
advantages and disadvantages of using hair analysis.
• Limit discussions to topics directly or indirectly related to environmental exposures.
Focus on the markers of environmental exposures or internal dose.
• Actively listen to one another and exchange ideas and different perspectives.
In addition to the panelists, approximately 50 observers attended one or both days of the meeting.
The observers included representatives from ATSDR, the Centers for Disease Control and
Prevention (CDC), other federal and state agencies, commercial laboratories, and professional
organizations. A list of the observers who attended the meeting is included in Appendix F.
Though the discussion at the meeting was largely among the panelists, observers were given three
separate opportunities during the meeting to comment or ask questions (see the agenda) and also
ATSDR Hair Analysis Panel Discussion
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were encouraged to provide written comments to ATSDR in response to the charge questions and
panel discussions. Written comments received from observers after the meeting are included in
Appendix G.
1.5 The Report Organization
The organization of this report generally follows the list of topics outlined in the agenda and
charge to the panelists. Section 2 includes a summary of opening remarks. Sections 3, 4, and 5
summarize the panelists’ comments and discussions related to analytical methodologies, various
factors influencing the interpretation of results, and toxicological considerations. Section 6 reports
overall conclusions drawn by the panel, including data gaps and research needs.
Comments provided by observers throughout the meeting are presented in Section 7. Section 8
lists references cited in this summary report.
Note: In subsequent sections, the panelists’ initials are used to attribute comments. They are as
follows: Dr. Robert Baratz (RB), Dr. Thomas Clarkson (TC), Dr. Michael Greenberg
(MG), Dr. Michael Kosnett (MK), Dr. Dan Paschal (DP), Dr. Sharon Seidel (SS), Dr.
LuAnn White (LW).
ATSDR Hair Analysis Panel Discussion
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SECTION 2
OPENING REMARKS AND PRESENTATIONS
Dr. Robert Amler, ATSDR’s Chief Medical Officer, opened the meeting by welcoming panelists
and observers and describing how the hair analysis panel discussions would help support the
agency’s public health mission. Dr. Allan Susten and Dr. Deanna Harkins, technical coordinators
of the panel, reviewed the scientific issues related to hair analysis and the impetus for convening
the hair analysis panel. They briefly described how hair analysis fits into the agency’s public health
assessment process, the goals and objectives of the panel discussions, and how the agency plans
to use the scientific information obtained from panelists and observers.
To help ground subsequent discussions, panelist Dr. Robert Baratz provided an overview on the
anatomy and physiology of hair. ATSDR’s and Dr. Baratz’s presentations are summarized below.
2.1 Welcome
Robert Amler, M.D.
ATSDR Chief Medical Officer
After welcoming all in attendance, Dr. Amler stated that ATSDR’s overall mission is to protect
people’s health by identifying and preventing toxic exposures. Because recognizing problems and
knowing how to evaluate them are key to the agency’s ability to assess potential health threats,
discussions such as those anticipated during the hair analysis meeting are of key importance. Dr.
Amler noted that such discussions will help ATSDR sort through the advantages and
disadvantages of using hair analysis in its exposure and health assessments.
Dr. Amler explained that the panel process has been shown to be a very effective means for
discussing and weighing scientific issues. He further explained that these panel discussions will
serve as a first step in developing agency guidance on the appropriateness of using hair analysis.
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Because it is only a first step, additional areas of discussions may be necessary. Dr. Amler
acknowledged that it would not be possible to obtain all the answers in this forum.
Dr. Amler thanked the individuals who were instrumental in initiating and organizing the panel
discussions, including Mr. Robert Williams, Director of ATSDR’s Division of Health Assessment
and Consultation (DHAC); Dr. Gregory Christenson, Acting Director of ATSDR’s Division of
Health Education and Promotion (DHEP); Dr. Allan Susten, DHAC’s Assistant Director for
Science; and Dr. Deanna Harkins, Medical Officer, within DHEP. He also thanked Dr. LuAnn
White for moderating the meeting. Lastly, he thanked all participants for their involvement in
what promised to be fruitful discussions.
2.2 Purpose of the Meeting and Charge to the Panelists
Allan Susten, Ph.D., D.A.B.T.
Assistant Director for Science
ATSDR/DHAC
Dr. Susten described how the agency seeks to use the best available science in conducting its
public health assessments. He indicated that the overarching goal for the panel discussions is to
review the state of the science of the hair analysis field and help the agency evaluate the overall
utility of hair analysis in its public health assessments. Specifically, the agency seeks to determine
when it might be appropriate to use hair analysis in evaluating possible exposures and/or possible
adverse health effects associated with environmental toxicants. Dr. Susten acknowledged that hair
analysis is used for other purposes (e.g., drugs of abuse, forensics) but said that the focus of this
forum was on the relevance of hair analysis to hazardous waste site evaluations.
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To help illustrate the nature of the scientific input that helps the agency evaluate exposures and
health effects, Dr. Susten displayed a “continuum” showing the components of ATSDR’s public
health assessment process (see Figure 2-1). In doing so, he described the following components of
the process:
• Exposure evaluation—Involves studying how hazardous substances can reach people,
studying the means by which people can come in contact with hazardous materials, and
determining the exposure concentration or dose at the point of contact.
• Target dose evaluation—Involves studying the distribution of a hazardous substance once
it enters the human body and determining the internal and biologically effective doses.
• Health effects evaluation—Takes a closer look at the dose-response relationships of the
substance(s) under evaluation and how the substance exerts its effect.
Dr. Susten explained that it is not enough to look at the estimated exposure concentration or
exposure dose when evaluating the potential that a particular exposure will lead to clinical disease.
To better understand the extent of exposures and the potential that a particular exposure will lead
to disease, one needs to study the biology and the toxicology of the substance involved.
Therefore, where possible, the agency seeks ways to estimate or measure internal dose and to
assess whether such exposures might be associated with adverse health effects.
Through its work over the past decade or so, ATSDR has recognized that knowledge of
environmental concentrations of hazardous substances alone is not enough to evaluate possible
health effects. In response, the agency established a special “exposure investigation” (EI) section
within DHAC to look specifically at biomonitoring and how it can be used to further inform the
public health assessment process. Dr. Susten presented the criteria developed by ATSDR to
determine whether biomonitoring should be considered to evaluate a site-specific exposure
situation:
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Figure 2-1. Continuum of events considered in the public health assessment process.
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• Can an exposed population be identified?
• Does a data gap exists that affects ATSDR’s ability to interpret whether a public health
hazard exists?
• Can the data gap be filled with an EI?
• How would the EI results impact public health decision-making?
Dr. Susten stated that the panel’s charge is to discuss scientific issues related to hair analysis that
will help the agency determine the criteria for determining when hair analysis might be a useful
tool in assessing public health exposures. He recognized that the science may not be available to
support all analyses and that research may be needed.
In convening this panel, Dr. Susten emphasized, the agency’s goal was to receive panelist and
observer input on the following general questions:
• When is it appropriate to consider hair analysis in assessing human exposures to
environmental contaminants?
• When is it inappropriate to consider hair analysis in assessing human exposures to
environmental contaminants?
• What data gaps exist that limit the interpretation and use of hair analysis in the assessment
of environmental exposures? What research is needed to fill these gaps?
• For what substances do reliable hair analysis methods exist (e.g., trace elements, organic
compounds)?
ATSDR’s primary interest in hair analysis, as was reiterated throughout the meeting, is using the
best science when responding to an individual’s request to interpret hair analysis results and
determining when hair analysis at the population level may be helpful in demonstrating that an
environmental exposure has occurred.
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2.3 Impetus for Panel Discussions—A Case Example
Deanna Harkins, M.D., M.P.H.
Medical Officer
ATSDR/DHEP
Dr. Harkins described a recent site-specific scenario that served as a primary trigger for
organizing the hair analysis panel. Specifically, hair analysis issues raised at a plating facility
prompted ATSDR to look more closely at the criteria that should be considered when choosing
hair analysis as an exposure assessment tool and the best way to interpret hair analysis results.
Dr. Harkins explained that the U.S. Environmental Protection Agency (EPA), ATSDR, and
relevant state and local agencies have been working together to address community health
concerns related to this particular facility. Dr. Harkins briefly reviewed how ATSDR evaluated
potential exposures associated with releases from the facility (i.e., by examining the nature and
extent of contamination and determining whether contaminants have moved from the source to a
point where people might contact them), noting that the agency studies both past and current
exposures. She re-emphasized Dr. Susten’s point that evaluating exposures is only one step in
evaluating possible public health hazards and that understanding the continuum of events between
exposure and resultant disease is critical to determining the likelihood that a given exposure will
have adverse effects.
Dr. Harkins provided the following summary of the issues reviewed during the assessment of the
facility:
• Investigations at and around the facility revealed the presence of Chromium VI (Cr
6+
) in
groundwater. In response, affected residences were supplied with bottled water since 1977
and municipal water since 1997. Therefore no recent exposures have occurred.
• Chromium is found naturally in rock/soils and can be found in three valence states (0, 3+,
and 6+). Also, Cr
3+
is an essential nutrient: it is required for normal glucose metabolism
and in the potentiation of the action of insulin, and it aids in the metabolism of fat and
ATSDR Hair Analysis Panel Discussion
2-7
cholesterol (Anderson 1997; Schroeder 1968; Mertz 1969; Hunter 1974). The National
Academy of Sciences has established a safe and adequate daily intake for chromium in
adults of 50 to 200 micrograms per day (µg/day) (NRC 1989). It has been reported that
the daily dietary intake of chromium for a typical American is approximately half the
minimum safe and adequate daily intake of 50 µg/day (Anderson and Kozlovsky 1985)
Chromium deficiencies have been shown to result in glucose intolerance, peripheral
neuropathy, and decreased fertility (Anderson 1997). Because chromium is an essential
nutrient and part of normal diets, it is difficult to measure body burdens from
environmental sources.
• The primary health concerns expressed by site community members include birth defects,
miscarriages, and cancer. Neither birth defects nor miscarriages are known to be
associated with chromium exposures. Lung cancer and other respiratory effects have been
associated with chromium exposures, but only in occupational settings where high doses
of Cr
6+
were received via inhalation. Cr
3+
is not classified by EPA, the National
Toxicology Program (NTP), or the International Agency for Research on Cancer (IARC)
as a carcinogen.
• Site community members wanted to use chromium levels in hair as proof that they were
exposed to chromium and clinically ill. In response, ATSDR, in cooperation with EPA, the
state health department, and outside experts, held a series of meetings with the
community, including the local medical community, to communicate why hair analysis
was not appropriate for this site:
– ATSDR determined that estimated chromium doses based on detected levels of
chromium in groundwater were lower than those associated with any adverse
health effects.
– Because of the stomach’s and gastric juices’ high capacity for the reduction of
Cr
6+
, ingested Cr
6+
is reduced to Cr
3+
within minutes (Kerger et al. 1996). As a
result, a person can tolerate ingestion of 50–100 milligrams of Cr
6+
per day
without risk of systemic effects (Donaldson and Barreras 1966; DeFlora and
Wetterhan 1989).
– Measuring chromium in hair would not demonstrate past environmental exposures.
– The health effects of concern to the community are not known to be linked with
chromium exposure.
Dr. Harkins stated that this case assessment led several ATSDR health assessors to inquire about
ATSDR Hair Analysis Panel Discussion
2-8
the overall utility of hair analysis. In turn, this has prompted the agency to look more closely at
the scientific issues associated with hair analysis and to work toward developing guidance on
when hair analysis might be useful in identifying environmental exposures and in evaluating
disease potential.
2.4 General Physiology of Hair—An Overview
Robert Baratz, M.D., Ph.D., D.D.S.
To provide a foundation for subsequent discussions, Dr. Baratz described the general
characteristics of hair and the underlying skin (e.g., structure, composition, growth patterns,
growth cycles). Understanding the characteristics of hair, the temporal and spatial patterns of hair
growth, and the factors that affect hair growth, for example, is important when collecting and
interpreting hair analysis data. Dr. Baratz’s presentation is summarized below.
• Anatomy of hair. Hair is encompassed in the follicle located below the skin surface in the
dermis, the fiber-rich layer that makes up the bulk of the skin. The follicle has a connective
tissue component (muscles) and glandular component (sebaceous glands). The muscles
elevate the hair and the glands lubricate the hair.
The primary components of the hair follicle are the dermal papilla and the follicle cells.
The dermal papilla is the “generative zone” of hair (it contains blood vessels, nerves, and
pigment-forming cells). The follicle cells generate the hair shaft; the hair shaft is composed
of essentially dead cells, which are the outermost layers of the epithelium and form a solid
cylinder in the dermis. Mitotic activity at the base of the hair follicle generates different
layers that will “keratinize” (see below).
• Keratinization of hair. Hair is composed of hard keratin (a family of proteins ranging in
size from 20,000 to 70,000 Daltons) and is chemically denser than other forms of keratin
(e.g., calluses, dander flakes). Keratinized cells contain more than 85% protein. Where the
hair shaft separates from the follicle it undergoes “disjunctive” keratizination, which
involves the splitting of layers and exposing surfaces not previously exposed.
Keratinized cells have a very distinctive appearance, and have tiny pores littering their
surfaces. The cells are flattened and tightly bound to their neighbors in a very complex
array. When they begin to split apart (by an unknown process), large “nooks and crannies”
are formed. These types of anatomical features allow external environmental agents to be
ATSDR Hair Analysis Panel Discussion
2-9
easily trapped in the outer surface of the hair.
• Elements found in hair. Because so many elements are ubiquitous in the environment and
therefore found in the human body, merely finding a particular element in the hair does not
prove that it got there via a specific route/source, or that finding it has clinical significance.
• Growth rates. Hair growth varies depending on body region. For example, average
eyelash/brow growth rates have been reported at 0.16 millimeters (mm) per day, scalp hair
at 0.34 to 0.36 mm/day, and beard hair at 0.38 mm/day. Growth rates also are affected by
age, gender, hair color, and ethnicity. For example, scalp hair in a prepubescent,
adolescent, adult, and older adult have been reported at 0.41, 0.30, 0.34, and 0.32
mm/day, respectively (Myers and Hamilton 1951).
Interindividual variability also occurs. Scalp hair grows at an average rate of 1 centimeter
(cm) per month, but can range from 0.6 to 3.36 cm/month (Harkey 1993). Thus, 12 cm
can represent 3½ to 20 months of hair growth.
• Growth cycles. Hair grows in phases (see Figure 2-2). Usually, more than 90% of the hair
is in the growing (or anagen) phase. The length of anagen varies from 2 to 6 years. The
longer the hair, generally the longer the phases. For example, long hair tends to grow
more slowly. Through apoptosis, the hair will begin to enter the relatively short catagen
phase, during which the follicle will begin to regress and move toward the surface (the
papilli will essentially disappear). During the next phase, telogen, the hair will actually fall
out. If the cycle is complete, a resting phase will follow and then the follicle will resume
the anagen phase. However, hair can “exit” the cycle and cease being a terminal hair. For
example, it can become a vellus hair (non-pigmented “peach-fuzz” hair) or the hair follicle
may permanently disappear, as is the case with male-pattern baldness.
Events known to affect the hair follicle and its cycle include local signaling events (e.g,
cytokines, hormones, adhesion molecules). However, no firm theory of cycle control
exists. Hypotheses include the presence of (1) a morphogenesis clock, (2) a cycling
inducer, (3) a desynchronizer, and (4) an actual cycle clock, but none of these are
specifically known.
• Generation, cycling, and “patterning” of hair. The hair growth cycle changes throughout
life and varies based on species and body location. Patterning of hair is important to the
generation and cycling of hair, and to how it relates to its neighbors (e.g., signaling goes
on in various regions to space follicles in even arrays). Because of similarities in hair
growth patterns, studying sheep hair growth has been useful in understanding human hair
growth patterns. Rodent hair growth models, on the other hand, may not be applicable to
humans because rodents have regional variation in hair growth; the hair cycles, but in
ATSDR Hair Analysis Panel Discussion
2-10
waves across the body.
Figure 2-2. The hair growth cycle.
• Substances affecting hair growth. A great number of substances can affect hair growth.
For example, some drugs, such as alkalating agents, are cytotoxic and can make hair fall
out (e.g., cancer chemotherapeutic agents). Other agents drive hair into telogen (e.g.,
heparin, Vitamin A, ?-blockers, L-dopa, lithium, and some of the non-steroidals). Drugs
that inhibit hair growth include parathyroid hormone (PTH) and PTH-related proteins.
Variable agents also exist, such as Vitamin D. At low concentrations, Vitamin D may
simulate hair growth, but at high concentrations hair growth is inhibited.
Substances such as testosterone, danazol, adrenocorticotropin hormone, metyrapone,
anabolic steroids, glucocorticoids, retinoids, and insulin can lead to hirsutism (growth of
hair where it does not normally occur). Cyclosporin, minoxidil, diazoxide, and
chromakalin increase the growth rate and size of hair (hypertrichosis). However, some
regional variation may occur. For example, steroids will decrease the rate of growth of
eyebrows, lashes, and hair on the extremities, but estrogen and testosterone will generally
ATSDR Hair Analysis Panel Discussion
2-11
stimulate the growth of pubic and axillary hair.
Other factors can potentiate or inhibit hair growth by affecting the growth of the dermal
papillae, hair, and follicle (see Table 2-1).
ATSDR Hair Analysis Panel Discussion
2-12
Table 2-1. Factor Effects
Factor Effect on Hair Growth
Beta-fibroblast growth factor
Platelet-derived growth factor
Potentiate growth of dermal papillae.
Transforming growth factor beta Inhibits follicle proliferation, if induced by
mitogens.
Interleukin-1 alpha Inhibits growth of hair and follicle.
Epidermal growth factor Stimulates growth.
Fibroblast growth factor-5 Inhibits growth.
Keratinocyte growth factor Stimulates growth; induces keratinization.
Insulin-like growth factor-1 Accelerates growth of hair and follicle.
Skin damage (e.g., cut, scrape, burn,
irritation)
Forces telogen to anagen (well-illustrated in
rodent models).
Allergens (e.g., food) Major changes in the skin, including hair loss.
Malnutrition Protein/calorie deficiencies inhibit hair growth.
Fungal infection Inhibits growth; hair may fall out.
Hypothyroidism Diminution of eyebrows.
Viral agents (e.g, HIV virus) Hair loss in patches.
Source: Jankovic and Jankovic 2001.
ATSDR Hair Analysis Panel Discussion
3-1
SECTION 3
SAMPLING AND ANALYTICAL METHODS
Panel discussions related to the sampling, handling, and laboratory methodologies used in hair
analysis centered around the strengths and weaknesses of existing procedures and the lack of
standardized methods for collecting and analyzing hair samples and reporting the results.
The group generally agreed that the technology exists to measure substances in hair, but
variations in sample collection, preparation, and analytical methods can drive what will be
measured in the final analysis. Therefore, the panelists encouraged the development of standard
protocols for hair analysis to help ensure the generation of reliable and reproducible analytical
results. In the interim, panelists encouraged laboratories to clearly document procedures used in
their analyses, and encouraged users to be cognizant of these procedures when interpreting
results. The group acknowledged that even if standard protocols were in place, the greatest
challenge would still be interpreting the results from a practical and toxicologic perspective (see
Sections 4 and 5).
Panelist Dr. Dan Paschal, research chemist at CDC, opened discussions on this topic with a brief
overview of the advantages and limitations of existing analytical methods and approaches related
to hair analysis. He emphasized that hair has real advantages in that (1) it can contain relatively
high levels of hazardous substances of potential interest, including elements and some organic
compounds, (2) it is easy to collect by relatively non-invasive methods, and (3) it is a stable
specimen. He also commented on some of the limitations: lack of precision and accuracy of hair
analysis results, external contamination, interindividual variations, lack of correlation with health
effects, and lack of believable reference intervals.
In setting the stage for discussions on analytical methods, Dr. Paschal commented on published
work related to reference intervals, detection limits, and hair concentrations of metals as a
ATSDR Hair Analysis Panel Discussion
3-2
function of age (DiPietro et al. 1989; Paschal et al. 1989). His specific comments are integrated in
the sections that follow.
3.1 Sample Collection Methods
The panelists offered some varying opinions regarding the best way to collect samples. Topics
discussed included preferred cutting tools, sampling location, and sample handling, as summarized
below.
• Selecting the appropriate cutting device. Panelists offered differing views on what type of
cutting tools should be used when collecting hair samples. One panelist noted that metals
can be released from scissors and therefore recommended using quartz instruments (RB).
One panelist pointed out that if a stainless steel device is used, chromium and nickel
results should be interpreted carefully, although he questioned whether use of stainless
steel would really make a significant difference in the analytical results. This panelist
questioned whether any data are available that document the extent to which chromium
and nickel in stainless steel contribute to sample levels compared to quartz tools (MK).
In theory, said another panelist, labs that have used stainless steel scissors (for example)
should run a careful blank for chromium. It is, however, difficult to do so: the variable
concentration that is present in the specimen would be measured as well as the variable
amount being introduced by the scissors. A chromium-free hair sample would be needed,
which is not feasible (DP).
This same panelist stressed the importance of being sensitive to possible psychological and
cultural issues when choosing a cutting tool. For example, children may be intimidated by
certain types of shears or other cutting devices. Also, in certain cultures, hair is considered
sacred. Touching, never mind cutting, is prohibited (DP).
One panelist suggested that if interferences due to the cutting instrument used are proven
to be significant, a new instrument might need to be created that would be practical for
field use (e.g., a relatively small tool with a quartz blade) (LW).
• Collection location. Because of differences in growth rates in different regions of the
scalp, the location from which a sample is taken must be carefully considered to ensure
consistency in measurements. For example, the anterior and the parietal regions grow
ATSDR Hair Analysis Panel Discussion
3-3
differently than the vertex (top), occipital (back), and temporal (side) regions (RB). In
response to a question whether an optimal location exists, one panelist noted that defining
an optimal sampling protocol is difficult (DP). At a minimum, it is important to choose a
protocol that is practical in the field setting.
Another panelist noted the desire to identify a reproducible point on the skull. He
suggested taking a sample from the nape of the neck (using a caliper to take the midpoint
between the external auditory meatus), an area where hair is known to grow in a particular
way (RB). Another panelist recommended sampling from the occipital region (SS).
In its 1989 study, CDC looked for a standard protocol but could not find one. Therefore,
CDC defined its protocol as follows: Approximately 500 to 1,000 milligrams of occipital
hair was collected using stainless steel scissors. Hair was pre-washed (using a non-ionic
detergent). Samples were stored in pre-cleaned plastic bags that were rigorously tested.
Therefore, within the context of the reference interval being generated, data were from
specimens collected in a like fashion (DP).
• Sample storage. One panelist stated that plastic bags or other plasticware should not be
used for storing hair samples unless the containers have been washed or cleaned. Zinc, he
said, is used in plastic molding processes. Because detection limits are precise and
relatively low, it is easy to record contamination from external sources; therefore,
whatever container is used needs to be looked at with great scrutiny (RB).
• Who should collect the sample. One panelist stressed that people not be allowed to collect
their own samples, put them in plastic bags, and ship them off to the laboratory (MG).
Others agreed: only trained professionals should collect hair samples.
3.2 Sample Preparation Methods
Panel discussions on sample preparation focused on washing protocols. The group agreed that
washing hair prior to analysis was an important consideration when external sources of the
substance(s) being studied exist. Panelist-specific comments follow.
• One panelist stated that no washing method can distinguish between external
contamination and internally deposited elements. She noted that a number of washing
procedure “camps” exist, including the “no wash hypothesis” (Chittleborough 1980), use
of a mild detergent, the washing procedure recommended by the International Atomic
Energy Agency that uses a solvent in water (adopted by many research groups), and more
ATSDR Hair Analysis Panel Discussion
3-4
radical procedures that use chelating agents. Wide differences in results have been
observed depending on the washing method (SS).
• External interferences can be especially significant with small children, so CDC uses a
standard washing protocol (DP).
• The extent to which washing is necessary depends on the substance being studied and how
the sample is being used. For example, washing is not necessary when one is testing for a
substance for which no external source exists (e.g., methyl mercury). Other key questions
to consider include: Are you looking at a spectrum or a specific agent/element at a
hazardous waste site? Are you sampling for exposure information? Are you sampling to
determine changes in exposures over time? (TC)
See Section 4 for additional discussions on hair washing, specifically as it relates to distinguishing
between endogenous and exogenous sources of metals.
3.3 Analytical Methods
The group noted that reliable analytical methodologies do exist to measure and verify the
presence of various substances in hair. Several panelists specified methods currently used for hair
analysis in their pre-meeting comments; throughout the meeting, they mentioned some of the
methods’ strengths and weaknesses, as well as their applicability. This section highlights the
points made during the meeting, but should not be considered an exhaustive discussion of existing
methodologies. The methods discussed include:
• Cold Vapor Atomic Absorption (AA). It was noted that this is the preferred methodology
for measuring methyl mercury.
• Inductively Coupled Argon Plasma Mass Spectrometry (ICP-MS). ICP-MS has
widespread use in commercial laboratories. It can be used to measure methyl mercury, but
it is difficult to get reproducible calibrations (DP). With certain types of mass
spectrometry, stable isotope studies can help show the incorporation rates of certain
elements in hair, which may help to answer some of the toxicology questions. For
example, a 20-day delay has been shown between the appearance of lead in blood and its
appearance in hair (TC).
ATSDR Hair Analysis Panel Discussion
3-5
• Inductively Coupled Argon Plasma Optical Emission Spectrometry (ICP-OES) or
Inductively Coupled Argon Plasma Atomic Emission Spectrometry (ICP-AES). Of the
commonly used methods, ICP-OES/AES is used the most (DP). This method makes it
possible to generate a large amount of data on a large number of elements. It is a “quick
and dirty” way of getting a global picture of the elemental composition of a hair sample.
It was noted that, historically, CDC used Jarrell Ash Model 1160 AtomComp (e.g., to
generate the data cited in DiPietro et al. 1989). CDC presently uses a Jobin Yvon Ultima
C (DP).
• Neutron Activation Analysis (NAA). NAA has been used in forensics to measure trace
elements in small quantities of hair. It can be used for segmental analysis of hair.
Segmental analysis can reveal isolated elevations of contamination along the hair and
provide information regarding the contamination of the length of the hair over time.
Identifying patterns over time can help distinguish whether exposure is endogenous or
exogenous (see also Section 4). These techniques are not widely commercially available,
however (MK).
• X-ray Fluorescence. This technique is amenable, nondestructive, and multi-element. It
also has the advantage of measuring the mass of hair as well as the amount of the element
present in that segment of hair (TC). Another panelist noted that the distribution of
mercury in segments along the length of a single strand of hair may be determined by x-ray
fluorescence.
• Proton Induced X-ray Emission (PIXE) Spectrometry. This method was brought into play
approximately 30 years ago. This method studies a cross section of hair, enabling
identification of external versus internal contamination. This method has not been used
very much because the instrument is expensive (TC). One panelist noted that single-strand
analysis can be problematic if hair is in the non-growing phase (RB), although it was noted
that this is not a problem if the sample is taken from the root (TC).
Another panelist commented on the variable success of the PIXE method. For example,
differentiating internal and external arsenic may not always be that straightforward. In
cases of internal uptake, peaks of arsenic on the external shaft of hair may be a
consequence of appreciable cysteine residues and sulphydral groups. In cases of external
contamination, washing procedures may lead to greater incorporation of external
contamination into the shaft (MK).
ATSDR Hair Analysis Panel Discussion
3-6
Given the various methodologies that might be used, several panelists pointed out the importance
of understanding the method and analytical equipment used when interpreting hair analysis results,
noting that it is the laboratory’s responsibility to clearly report the method used, quality assurance
measures taken, any possible interferences, etc. Further, the data user should carefully consider
this information when evaluating the results.
As stated by one panelist, it is easy to standardize measurements by using good standards and
good laboratory practice (use of blanks, use of external verification) (DP). While the group
recognized that valid methods exist, several panelists stressed that the challenge lies in the
interpretation (see Section 4 of this report)
3.4 Other Methodological Considerations
The group discussed a number of other issues that influence the analytical results and should be
considered when choosing methods and evaluating analytical data.
• What amount of hair is needed for reliable analyses? CDC has used between 500 and
1,000 milligrams of hair in its studies (DP). Another panelist commented that the amount
selected depends on the analytical method used, but he is more accustomed to sample
sizes in the 50 milligram range (TC). Down the road, there may be an interplay between
the sensitivity of the method and the quantity of hair needed for analysis.
• To what extent should multi-element analytical approaches be used? The group agreed
that a targeted (single-chemical) approach is preferable when analyzing hair for a
particular environmental contaminant. The analytical method selected needs to be
considered in the specific context of the substance and exposure situation under
evaluation; both time and element need to be targeted (RB, MG, MK).
Serious interference problems can exist with instruments that test for a spectrum of metals
(e.g., ICP instruments) (DP). According to one panelist’s observations, laboratories do
not always appear to account for these interferences: inconsistencies in approaches are
seen across laboratories using ICP-MS and ICP-OES (SS). When performing OES, one
must take a lot of care in choosing the emission wavelength used in the measurement.
ATSDR Hair Analysis Panel Discussion
3-7
Interferences from other elements can occur and must be considered. This is particularly
true when one uses ICP-MS for elements with masses less than 80. Peaks can be the result
of molecules made in the process of generating the ions. These can interfere with the
peaks you are trying to measure (e.g., argon chloride and arsenic, both with nominal
masses of 75 atomic mass units). A high-resolution MS, however, can resolve two such
peaks (DP).
• Other interferences. Metals in acid solutions, as well as paint, dusts, gloves, etc. in the
laboratory setting can be detected by the instruments used for hair analysis. Looking at
low-level metals in a hair sample is therefore not a simple exercise (RB). These
interferences might potentially overwhelm the amount that you may be seeking to measure
in the hair sample (MK).
• What about organic compounds? A hair assay for benzene is being developed that is
evaluating metabolic products in hair (data are proprietary). Such an assay may have a
great impact on determining the feasibility of using hair analysis for organic chemicals
(MG).
• Quality assurance and quality control. It is the responsibility of the laboratory to
demonstrate its quality control procedures, such as standardizing procedures, running
blank measurements, calibrating equipment, and verifying measurements externally
through proficiency testing programs.
ATSDR Hair Analysis Panel Discussion
4-1
SECTION 4
FACTORS INFLUENCING THE INTERPRETATION OF ANALYTICAL RESULTS
Panelists identified several factors that influence, and more often than not can limit, the
interpretation of hair analysis results. In light of these factors, the panelists generally concluded
that hair analysis findings need to be used and interpreted very cautiously. Even if issues related to
the reliability and reproducibility of the data are resolved, panelists stressed repeatedly, several
factors limit the utility of hair analysis as an exposure and diagnostic tool. Scientists and clinicians
currently know little about what such measurements mean in terms of predicting or treating
clinical disease (see also Section 5, Toxicologic Considerations).
During the meeting, several factors influencing the interpretation of hair analysis data were
discussed:
• Inconsistent sample collection and preparation methods (e.g., sample location, cutting
method, sample storage). (Panelist discussions related to methodological issues are
detailed in Section 3.)
• Difficulties in distinguishing metals deposited externally from those incorporated internally
from the hair follicle.
• Exposure chronology and conditions (e.g., exposure period of interest, hair growth cycle,
other exposures, etc.).
• The questionable reliability and variability of “reference” ranges. That is, what defines an
“elevated” level?
4.1 Distinguishing Between Endogenous and Exogenous Sources of Metals
All of the panelists agreed that using hair analysis as an exposure or diagnostic tool for metal
contamination is severely limited by difficulties in distinguishing between internal and external
sources of metals. It is further complicated by the natural occurrence of many of the trace
ATSDR Hair Analysis Panel Discussion
4-2
elements (several of which are essential nutrients) within the body. The group recognized,
however, that this distinction is not a limitation when a metabolite or a substance with no external
source is being measured (e.g., organic compounds such as methyl mercury or many drugs of
abuse).
Dr. Kosnett led discussions on the difficulties that exist in distinguishing endogenous and
exogenous substances in hair. Other panelists expanded upon these issues. Individual points are
summarized below.
• Hair analysis data do not necessarily enable you to determine where the measured
contaminant came from and how it got there. High hair levels may provide “markers of
potential exposure,” but that does not tell us how much is internally incorporated. If hair
analysis is used in ATSDR’s evaluations of exposures to contaminants in air (e.g., in the
form of particulates), water, or soil/dust, it must be realized that this distinction cannot
necessarily be made (MK).
• An Alaskan study of arsenic levels in tap water, urine, and nails (Harrington et al. 1978),
reveals some interesting trends. Individuals drinking bottled water, but bathing in tap
water with arsenic averaging 345 micrograms per liter (µg/L), had higher average levels of
arsenic in hair (5.7 parts per million, or ppm) compared to those drinking and bathing in
tap water with arsenic containing 30 µg/L (0.46 ppm arsenic in hair). Urine levels were
similar, however. This example helps illustrate the difficulties in using hair concentrations
alone to draw inferences regarding the magnitude of the internally absorbed dose of a
metal (MK).
• Though they are not applicable to the example above (based on arsenic toxicokinetics),
another reviewer noted that the following caveats could further confound the
interpretation of such a scenario: (1) other exposures could be occurring (e.g., cooking,
brushing teeth), (2) dermal absorption could be occurring, and/or (3) a pool of the
contaminant could be sequestered in and later released from the bone (e.g., this can be
true with tetracycline) (RB).
• Effect of washing hair. Dr. Kosnett described various studies that have looked at the role
and/or effectiveness of washing hair in order to distinguish between endogenous and
exogenous sources of arsenic. These studies suggest that no truly good washing method
exists to remove arsenic: If hair is not washed aggressively, exogenous arsenic will remain.
If hair is washed too aggressively, endogenous arsenic may be removed.
ATSDR Hair Analysis Panel Discussion
4-3
ATSDR Hair Analysis Panel Discussion
4-4
– Smith (1964) showed that detected concentrations of arsenic in hair will vary
depending on washing method, with no method shown to be capable of removing
all arsenic. The results of applying different washing methods (to hair purposely
externally contaminated with 12.08 ppm arsenic) are highlighted in Table 4-1. The
arsenic concentration in hair before contamination was measured at 0.14 ppm.
Table 4-1. Effect of washing method and time on arsenic levels in hair
Washing Method Washing Time (mins) Arsenic (ppm)
Water 5 9.16
15 5.78
30 5.05
60 5.03–6.21
Detergent (5%) 60 4.20–4.93
HCl (N) 60 4.92–6.26
NaOH (N) 60 0.40–0.70
Source: Smith 1964.
– Van den Berg et al. (1968) showed similar findings. Depending on the washing
regime, this study revealed that even after 1,600 minutes of washing, externally
deposited arsenic was still detected (MK).
• Measuring total concentrations in hair. Depending on the purpose of your testing, it may
not be critical to distinguish between internal and external contamination. For example, in
an industrial hygiene exposure investigation, identifying elevated levels of an element may
be enough to suggest that the potential for exposure exists and protective measures are
needed. While urine data may reveal that existing protective measures have prevented
internal exposures, knowledge that employees have exposure potential may be important
(e.g., contamination could be carried home) (MK, TC, MG). Several panelists reiterated,
however, the limitations of using such data for clinical evaluation or interpretation.
ATSDR Hair Analysis Panel Discussion
4-5
4.2 Temporal Considerations and Exposure Conditions
Panelists agreed that, in determining whether to use hair analysis and in interpreting analytical
results, one must carefully consider exposure chronology and conditions. Because hair growth is a
factor in evaluating when a contaminant might become incorporated in the hair, one must consider
it when deciding whether sampling hair will identify exposures over the period of interest. With
regard to this, the panelists discussed these topics:
• Window of exposure that hair levels may represent. Growth rate is a key consideration.
Assuming growth at approximately 1 centimeter a month, the hair on the average person’s
head generally represents a year or less of time. Therefore, hair analysis is not the best
biological medium to serve as an indicator of very recent exposure or past exposures
(greater than 1 year) (RB).
• Using segmental analysis to study exposures over time. If hair is looked at in a micro or
segmental way, temporal patterns of exposure may be identified. Understanding when
exposure might have occurred may be useful in documenting some historic exposures. As
mentioned in Section 3, neutron activation analysis has been used to identify isolated
elevations along small segments of a hair (e.g, millimeter[s] in length) (MK).
Segmental analysis has been shown to find isolated arsenic peaks at distal points along the
hair shaft. For example, studies of past acute suicidal exposures to arsenic show distinct
peaks migrating away from the scalp (Leslie and Smith 1978). Such analysis can reveal
past exposures even when current urinary levels are normal. Curry and Pounds (1977)
demonstrated peak concentrations of arsenic in hair migrating away from the scalp
following the administration of medicinal arsenic (1 hour to 72 days after ingestion).
Segmental analysis may help ATSDR scientists identify past elevated exposures (e.g.,
acute high exposures from a spill event). Segmental analysis may also rule out exposures.
Houtman et al. (1978), for example, studied hair in a population exposed to an accidental
release of arsenic dust. Segmental hair analysis revealed that concentrations on the distal
parts of hairs were elevated. However, it was determined that the higher levels were
detected on portions of hair that would have been fully formed before the accident, thus
establishing that the arsenic in hair was the result of external contamination. In some
settings, a relatively uniform distribution of a metal such as arsenic along the length of
sampled hair can reflect relatively stable, chronic ingestion, but even in those settings the
contribution of external contamination cannot always be readily determined (MK).
ATSDR Hair Analysis Panel Discussion
4-6
The challenge of using segmental analysis to demonstrate exposure patterns is that it
requires techniques that will enable the analysis of small quantities of hair (e.g.,
subcentimeter sections). It also requires collection of hair in a careful way, to preserve the
orientation of the hair. Further, it has been shown that uptake of arsenic—even on
deliberate external contamination—was not uniform. It has been hypothesized that the use
of shampoos might account for the uneven distribution. This observation might limit the
interpretation of segmental analysis for measuring patterns of endogenous levels (MK).
It was also noted that concentration increases towards the tip of the hair because it is
exposed longer. This pattern is typical with external lead exposures. Increased
concentration toward the tip is a useful clue regarding the extent of external contamination
(MK, TC).
• Understanding exposure conditions/histories. Panelists suggested obtaining complete
exposure histories as part of any hair analysis evaluation. A clinician or health assessor
needs to understand the exposure situation and work within a framework of knowing
when data may have a valid use. Using an exposure questionnaire as part of any hair
analysis exercise will help the clinician/assessor identify sources of exposure, both site-
and non-site related. Such information will ultimately help the assessor put available data
into perspective (DP, TC, SS).
• Age. The age of the individual or population tested can affect the results and interpretation
of hair analysis. Studies suggest, for example, that alkaline earths and zinc are not excreted
as much in early years of life. The opposite is true with aluminum, of which children
excrete higher levels than adults (Paschal 1989). When skeletal growth stops, the
excretion of these substances into hair is relatively constant. As part of its National Health
and Nutrition Examination Survey 99+ (NHANES), CDC studied mercury levels in the
hair of children and women of childbearing age. Data suggest that children had lower
mercury levels than adults (CDC 2001a; CDC 2001b) (DP).
4.3 Reference/Background Ranges
Discussions regarding reference ranges focused on uncertainties associated with levels of metals,
etc., in “healthy” or “unexposed” individuals and the variability of reference ranges used by
different laboratories. The panelists discussed how the uncertainties play out when one tries to
interpret results of hair analysis.
ATSDR Hair Analysis Panel Discussion
4-7
Individual comments regarding currently available reference range data and inherent limitations
are detailed below:
• The panelists discussed the importance of first clearly defining the term “reference range.”
Two panelists expressed concern about using the term synonymously with “normal”
because it implies that knowledge exists about associated health status, when in fact such
information is largely unavailable. Reference ranges do not represent “background” or
“controls,” nor do we know baseline levels for “normal” states of health (SS). We do not
know what should be present in “healthy” hair (LW). Others suggested that it is
background data that is ultimately being sought, noting that possible geographic and
demographic differences need to be considered.
• A “normal” range does not exist for many elements. Unlike drugs, the presence of which
would be considered “abnormal,” normal ranges need to be identified for metals. Building
the database of normal levels would help assessors better understand and interpret hair
analysis results. Considering hair data in the absence of reference data against which to
compare them is therefore of limited utility (RB).
• The availability of a reference range does not mean we know the background or typical
levels of endogenous incorporation. It does not necessarily represent what occurs
naturally. It may represent external exposures to ubiquitous levels of contaminants (e.g.,
lead dust, etc.) (MK, TC). For ATSDR’s purposes, the key is distinguishing site exposures
from non-site exposures (e.g., What are background levels where no known external
exposure sources exist?). For example, will we be able to discern whether levels of a
contaminant of interest are elevated in a potentially exposed population (LW)?
• DiPietro et al. (1989) reported analytical results for 271 adults, ages 20 to 73 years, for
selected elements. In comparing the findings of this study with mean hair concentrations of
the same elements reported by others, investigators concluded that results compare
relatively well, given limitations and variability in hair analysis (DP).
• It might be useful to draw a distinction between essential trace elements and non-essential
trace elements. One would expect a reference level of the essential trace elements in hair.
The presence of non-essential elements, on the other hand, would suggest environmental
exposure, deposited internally or externally (TC).
• According to two panelists, available reference ranges are often biased and based on small
numbers. Some reference ranges are based on one or two old case reports (RB, MG).
ATSDR Hair Analysis Panel Discussion
4-8
• The validity of samples used to develop a reference range in the first place is unknown
(RB).
• Available reference values may not relate to the population under study (RB).
• Reference ranges with an approximate 100-fold difference have been used by different
commercial laboratories. What does this really mean from a biological perspective? (SS)
• One panelist emphasized that more important than understanding reference ranges is
gaining an understanding of whether chemical-specific value have toxicologic or clinical
significance. The availability of reference range information alone is inadequate to assess
the clinical significance of a particular laboratory result; the fact that a reference range has
been exceeded does not establish that the individual sustained a toxicologically significant
dose (MK). Another panelist reminded the group that establishing reliable reference levels
will inform assessors about the possible extent of exposures (LW).
• One panelist questioned whether CDC might consider additional hair analysis as part
NHANES efforts—providing an opportunity to collect data on a cross section of the
population. It was speculated that if the science supported the need for such data
collection, it could be proposed (funding aside) (LW, DP). NHANES 99+ did measure
hair mercury of a selected subpopulation (children ages 1 to 5 and females 16 to 49 years)
(CDC 2001a).
ATSDR Hair Analysis Panel Discussion
5-1
SECTION 5
TOXICOLOGIC CONSIDERATIONS
The panelists agreed that, in order to interpret hair analysis data in any meaningful way, scientists
need a greater understanding of substance-specific relationships between levels in hair and other
body compartments, including target tissues, and how those levels relate to adverse health
outcomes. Much of the toxicology discussion, accordingly, centered around data gaps and
research needs.
The panel chair stressed the importance of understanding to what extent a particular substance
might enter the body, what could conceivably get into hair, and ultimately how such information
can be used as an indicator of exposure and/or of possible clinical effects. Specific questions to
consider included:
• What are the substance-specific pharmacokinetic factors (e.g., intake, absorption,
distribution, excretion) that can influence the biologic uptake of specific substances and
the concentration delivered and incorporated into the hair? How should half-life and
possible storage pools within the body be considered?
• What substances are transported to the hair, and by what mechanism are they transported
(e.g., how are environmental substances of interest incorporated into the hair)?
• What is the dose that causes effect at the target organ? If this is known, how does it relate
to the concentration in the hair matrix?
• How do different patterns of exposure over time (e.g., as may be revealed by segmental
analysis) help us understand possible acute versus long-term exposures, and how might
these patterns correlate with potential health effects?
ATSDR Hair Analysis Panel Discussion
5-2
5.1 Pharmacokinetic Issues
The group acknowledged that little is known about the transfer kinetics of substances into hair
(i.e., their “normal” percolation or rate of appearance in hair). Factors such as transit times, pools
in the body, permeability of basal membranes, and co-factors that may be involved in transit are
not known. Without this knowledge, interpretation of hair analysis results is greatly limited.
Individual panelist input focused on possible ways to fill data gaps. Specifically:
• Hair is a nonvascular tissue (separate from liquid phase transfer kinetics). Understanding
the rate of uptake in the hair, if any, for substances of interest is of critical importance.
Experimental models are needed (RB, MK).
• Implanting human hair on hairless mice, administering a radioactive isotope, and following
its movement to hair may be an effective method for determining the incorporation of
metals into hair (TC).
• Studying the uptake of arsenite used in the treatment of leukemia might be a possible
human model to use to increase our understanding of pharmacokinetics and dose-response
relationships, realizing that administered doses are much higher than they would ever be
expected in an environmental setting (MK).
• Identifying the “transportable” form or metabolite(s) of substances of interest may provide
the best biomarker. Methyl mercury may serve as a model. The key is understanding the
transport mechanism. It may be worthwhile to pursue organo metals and their behavior
(e.g, dimethyl arsenic acid, butyl tin); they may serve as more unique markers of exposure
(TC, MK, SS, LW).
• When interpreting data, studying nutritional status should be considered because it may
play a role in the uptake and distribution of metals. For example, iron and calcium can
increase the uptake of lead into the hair. Zinc levels in hair may be high in “failure to
thrive” cases because hair has stopped growing (LW, SS).
• Obtaining data to better correlate exposure, blood/urine, and hair levels would enable a
better understanding of the relationship of elements in the various body compartments. It
would help correlate external concentration with internal doses. Few such data exist, with
the exception of NHANES data, which evaluate lead levels across hair, blood, and urine
ATSDR Hair Analysis Panel Discussion
2
EPA has established a methyl mercury benchmark dose (in maternal hair) of 11 ppm. This is
equivalent to 46 to 49 micrograms of methyl mercury per liter of maternal blood; the critical effect is
developmental neurological abnormalities in offspring (U.S. EPA 2001).
5-3
(which correlated poorly). It was speculated that such substance-specific relationships
could be studied further as part of the NHANES program (DP, LW).
5.2 Dose-Response and Clinical Relevance
The panelists concurred that relationships between hair and any kind of measurable outcome have
only been established for methyl mercury and arsenic. The relationship between maternal hair and
fetal brain levels of methyl mercury is the only well-documented hair/target tissue relationship;
one panelist pointed to the benchmark dose of methyl mercury of 11 ppm in hair established by
EPA
2
(RB, SS, TC, MK). Data for arsenic relate largely to forensic examinations; data do not
exist for arsenic that offer disease-predictive value (e.g., long-term health outcomes). The group
could not identify any other environmental substances for which any hard and fast clinical
relationship has been established. Dose-response curves simply do not exist.
Panel discussions regarding current knowledge and the implications for using hair analysis are
highlighted below:
• Can hair analysis predict cancer and other common community health concerns?
Common community health concerns relate to health outcomes such as cancer and birth
defects (according to Dr. Harkins, ATSDR). Questions relate to what harm may have
been done or what future risk may exist as a result of environmental exposures.
One panelist stated that it is not likely for hair analysis to be used to any large extent to
address public health or individual concerns related to teratology or carcinogenicity (MG).
This panelist did note, however, that current efforts to measure benzene in hair might in
the future provide some predictive value for aplastic anemia, but only because of the
known association between benzene and aplastic anemia. Another panelist re-emphasized
that hair only provides an approximate 1-year time frame in terms of possible exposures,
further supporting the conclusion that hair analysis has little predictive value in studies of
ATSDR Hair Analysis Panel Discussion
5-4
the carcinogenic potential of environmental exposures (RB). Judging from the current
understanding of underlying science (particularly for carcinogens), another panelist
commented, he would rather have exposure history instead of hair analysis data (DP).
• Importance of establishing a clinical basis prior to testing. A fair amount of discussion
occurred regarding the criticality of establishing a clinical basis before pursuing hair
analysis. Several panelists questioned the relevance of measured levels if they cannot be
used to predict health endpoints. As in other discussions, the dichotomy of using hair
analysis as an exposure tool versus a clinical tool was very evident.
The physicians on the panel strongly stated that a clinical basis must be established before
hair analysis can be considered a useful tool. One panelist stressed that one should not
collect data that one is not prepared to use (RB). In response to an acknowledgment that a
community might press for hair analysis—for example, even in the absence of supportable
scientific data—two panelists were emphatic that science must be the focus: politics,
litigation, and any other underlying agendas must be put aside (RB, MG). In general, one
must consider what doses, under what circumstances, are relevant (RB). Part of the
challenge lies in communicating to the public what the current science enables us to do.
No absolutes exist in toxicology and medicine. The exposure, the form, the presentation,
and the distribution must be placed in the right context (RB).
Another panelist strongly stated that the predictive value of the test result must be
weighed and communicated. He emphasized that should the science clearly show no
plausible correlation for a particular substance or exposure situation, then hair analysis
should not be considered (MK).
One panelist reiterated that in the absence of dose-response data, hair analysis may simply
give us a better sense of exposure; it “raises some suspicion” of possible exposure and
effects (TC). Measurements of particular substances in hair may be indicative of exposure,
but not the risk of disease (LW).
• Understanding the function of various elements in hair. In order to ultimately understand
dose-response relationships and the clinical significance of exposures, scientists need a
better understanding of the role of various elements in the hair. Two panelists briefly
commented on the basic lack of understanding of the function, if any, of metals, cations,
etc., in hair. From a practical point of view, keratinized cells “are on their way out” with
the purpose of protecting the skin and providing warmth. It is therefore difficult to
determine the biological meaning of individual components in hair. Some elements
maintain homeostasis (e.g. potassium). Other elements are co-factors in synthesis (e.g.,
chromium in collagen synthesis). Some elements, on the other hand, are ubiquitous and
have no known purpose (e.g., lead, uranium) (RB, LW).
ATSDR Hair Analysis Panel Discussion
5-5
ATSDR Hair Analysis Panel Discussion
5-6
• Substances for which hair analysis might prove useful. Panelists provided a couple of
examples of other elements for which hair analysis may hold some promise. The panelists
agreed that if strong hypotheses exist, the scientific merit of these types of relationships
may be worth pursuing (RB, DP, TC, SS).
– Thallium might be useful in hair because it is an unusual toxicant. (Thallium was
suggested based on a “classic picture” of thallium intoxication studied by CDC in
Florida.) (DP)
– The possible correlation between excessive manganese levels (as measured in hair)
and violent and other antisocial behaviors has been studied in incarcerated
populations. While study findings suggest some correlation and have some merit
on the surface, many potentially confounding factors exist that need to be
examined more closely, such as hair color, race, and social context (DP). Panelists
questioned the overall scientific merit of the correlation, based on the possible lack
of biological plausibility—that is, symptoms are not necessarily consistent with
documented health effects associated with manganese (DP). One panelist noted
that manganese exposures would more likely be expected to cause neurological
effects that lead to more withdrawn or inactive behavior (e.g., Parkinson-like
symptoms) (SS). Another panelist noted that, because manganese is an essential
trace element, it is reasonable that it will get into hair (TC). Another study, by
Bader et al. (1999), showed some correlation between axillary hair and airborne
manganese (attributed to contamination by dust and water), but overall did not
support the use of hair for manganese analysis (SS).
5.3 Choosing the Best Biological Marker
Panelists briefly discussed if and when hair may be more advantageous than other biological
samples, such as blood or urine. From both an exposure and clinical perspective, panelists
considered which approaches were most productive. Generally, based on current science, they
concluded that hair may be used to provide historical exposure perspective within a fairly small
window of time (i.e., 1 year). Panelists’ views are highlighted below:
• Two panelists emphasized that the following question needs to be answered in making
such a determination: When might a substance be detected in hair, but not in urine
(measure of excreted amount) or blood (measure of body compartment) (MG, LW)?
Another panelist encouraged consideration of the following question: For what substances
ATSDR Hair Analysis Panel Discussion
5-7
do we have knowledge of the toxicologic implication of the measurement of the substance
in hair compared to the measurement of the substance in other biological specimens (e.g.,
urine, blood, bone) (MK)?
• How do we move toward establishing the “gold standard?” Could hair samples be a better
way to non-invasively get a sample? Is it a valid measure and how does that relate back to
blood or target organ levels (LW)?
• Hair samples may be considered preferable or less invasive under certain situations (e.g.,
pediatric exposures) (SS). Others commented that collecting blood or urine samples did
not appear to be that much of an obstacle (MK, LW).
• Hair may be considered for retrospective purposes when blood and urine are no longer
expected to contain a particular contaminant. Again, the distinction between the use of
hair analysis as an exposure tool, rather than a diagnostic tool, was made (LW).
• From a clinical point of view, it is important to focus on what substances are of greatest
interest, then ask what is the best way to analyze them. Is hair analysis the best way to
measure body burden (instead of blood or urine)? For example, we may be able to
analyze/identify many elements in hair, but it still may be more useful to look at blood
levels. Blood may simply be the better body compartment to test from a scientific point of
view regardless of whether we can test for a particular substance in hair. That is, what can
potential levels in hair tell us that blood levels do not (RB)?
• An acute spike in hair might help document exposure, but generally will not help from a
diagnostic perspective (MG, LW). Acute exposures are best measured through blood or
urine (RB).
• Growth rate is a key consideration. Assuming growth at approximately 1 centimeter a
month, the hair on the average person’s head generally represents a year or less of time.
Hair analysis will therefore have limited usefulness in cases where exposures occurred
more than a year prior to an exposure assessment (RB). While hair analysis may provide a
snapshot of exposure conditions, it is not likely to predict long-term exposures (SS).
ATSDR Hair Analysis Panel Discussion
3
This statement addresses only exposure to environmental contaminants and does not address
substances of abuse.
6-1
SECTION 6
CONCLUSIONS AND RECOMMENDATIONS
On the second day of the meeting, panelists reviewed earlier discussions and drew overall
conclusions. During these final deliberations, panelists commented on the overall state of the
science in hair analysis, the major limitations of hair analysis, topics for which a complete
scientific understanding is not available, and research that might permit a better understanding of
the science. The panel’s general conclusions and recommendations are summarized below.
6.1 What Is the State of the Science of Hair Analysis?
Although consensus was not required, the panelists did agree on the following overall conclusion
statement:
For most substances, insufficient data currently exist that would allow the prediction of a
health effect from the concentration of the substance in hair.
3
The presence of a substance
in hair may indicate exposure (both internal and external), but does not necessarily indicate
the source of exposure.
6.2 When Is It Appropriate To Consider Hair Analysis in Assessing Human Exposures
to Environmental Contaminants?
The panelists recognized that hair analysis can serve two distinct purposes: (1) as a tool in
identifying exposures (Is the substance reaching people? Does a competed pathway exist?) and (2)
as a clinical tool (What is the threshold for adverse health effects?) The latter is where the largest
data gaps exist. The panelists agreed that a body of literature describes specific conditions and
uses of hair analysis for methyl mercury and arsenic. There may be a unique forensic setting for
ATSDR Hair Analysis Panel Discussion
6-2
other metals. Segmental analysis with ultra-sensitive techniques may have a role in special
cases—that is, subject-, substance-, and situation-specific cases (e.g., identification of high-dose
acute exposure).
The group agreed on the general criteria that need to be fulfilled in order to consider hair analysis
a valid assessment tool. Panelists encourage assessors to ask: What is the predictive value of a
positive or negative test? Are data available to determine whether the measured level is of
sufficient magnitude to be of pathological or public health importance? The following factors are
key to that determination:
(1) Defining the type of exposure that may have occurred and over what time period. (What
do exposure histories tell us about the likelihood that a particular substance will be in hair
at the time of testing?)
(2) Understanding the type of substance and its behavior in the body. (Are data available that
relate exposure to proportional uptake in hair? Is uptake in hair biologically plausible? Is it
a marker of external exposure?)
(3) Identifying the clinical relevance of a positive or negative finding. (Are any dose-response
data available that will make useful interpretations possible?)
The panel provided this specific input on when hair analysis can be useful:
• From an exposure perspective, hair analysis can be useful for simply identifying or
confirming exposures. Issues raised or reiterated included (1) the difficulty in
distinguishing between internal and external contamination, (2) the qualitative nature of
any such finding, (3) the inability to confirm the source of the substance under study, (4)
the dilemma of not being able to “take it to the next step” (i.e., to use the results as a
clinical tool). To overcome issues 1 through 3, it was noted, it may be more feasible for
some substances to confirm the contamination source (e.g., based on the specific signature
of the substance[s] of interest). Also, more sophisticated studies (e.g., looking at stable
isotopes of certain metals) may now be possible (TC, MK, SS, LW).
ATSDR Hair Analysis Panel Discussion
6-3
• According to the current science, the primary utility of hair analysis is as a measure of
historical exposure. The research focus needs to be on seeking data that establish dose-
response relationships (SS).
• From a clinical perspective, the following conditions must be satisfied before hair analysis
can be viewed as a reliable means to measure a particular substance: (1) hair contains a
substance concentration that correlates with body organs, tissues, or fluids; (2) correlates
exist and are predictive from a clinical and/or forensic perspective; and (3) hair can be
used reliably to sample individuals, groups, and/or populations to measure the substance
(RB).
• Theoretically, potential substances for which hair analysis may be useful include those for
which the route of exposure would limit external contamination and those for which a
metabolite might be measurable (MK).
• Because of general hair growth and cutting patterns, for exposures longer ago than a year
or quite recent, hair analysis is not useful (RB, LW).
• Depending on the test or element under study, a negative test can help to rule out an
exposure and any potential problem. Again, “negative” needs to be defined. That is, what
is elevated (RB, MK, TC, LW)?
• Before considering hair analysis, a practical consideration is questioning whether there are
any laboratories available that provide cost-effective services and reliable results (DP).
6.3 What Are the Limitations of Hair Analysis? What Data Gaps and Research Needs
Exist?
Throughout the 1½-day meeting, the group identified various factors that currently limit the use
of hair analysis in evaluations of environmental exposures. No specific research agenda was
ATSDR Hair Analysis Panel Discussion
4
One panelist cited a pre-print of a paper by Jason Ditton, professor of criminology at Sheffield
University, England, as a good overview of the potential problems associated with interpreting hair analysis
results, which he felt were on par with panel discussions. The paper highlights uncertainties and intra-
individual variability in hair growth rates and substance-specific incorporation rates. It also describes the
challenges of external contamination issues, including variability in results depending on wash procedures.
The paper concludes that hair analysis is not an “absolute dosimeter,” but rather a “chronometrically
operating relativistic dosimeter” (RB).
6-4
proposed, but gaps in the scientific data were clearly identified.
4
The limitations and data gaps
were recapped by the panelists as follows:
• The lack of standard procedures for sample collection.
• The lack of standardization of methods and quality assurance/quality control (QA/QC)
among laboratories.
• The possible over-interpretation of results far beyond the current body of scientific data
and in light of limitations of techniques and procedures.
• External contamination from a variety of sources, which lowers sensitivity (e.g.,
environmental, hair treatments, personal hygiene, and others).
• The lack of a body of evidence to demonstrate the effect of washing hair on analytical
results.
• The lack of reference ranges in which to frame the interpretation of results. Reliable
reference ranges are needed—specifically, background or expected ranges in different
geographical areas or regions. Reference ranges should be applicable to population of
interest. The DiPietro (1989) data are a good start, but more data characterizing regional
differences are needed.
• The lack of data related to uptake/incorporation of environmental contaminants into hair.
For both metals and organic compounds, neither kinetic models nor metabolite data are
known or fully understood. Identifying metabolites of substances of interest would be
helpful, because they could serve as markers of internal exposure.
• The lack of correlation between levels in hair and blood and other target tissues.
• The lack of an epidemiologic database linking substance-specific hair levels and health end
points.
ATSDR Hair Analysis Panel Discussion
6-5
It was re-emphasized that identifying measurable levels of particular substance in hair does
not mean an adverse effect will occur or has occurred. From a medical perspective, many
panelists felt strongly that there is little point in performing hair analysis for a substance if
the findings cannot be used as a diagnostic aid. Justification needs to be provided for
choosing hair analysis over blood or urine analysis, and a connection to a clinical endpoint
is needed.
• A limited knowledge of the biological variations of hair growth with age, gender, race, and
ethnicity.
• Insufficient data on environmentally relevant organic compounds in hair. However,
information on testing for pharmaceuticals and drugs of abuse may have value for those
looking at organic compounds.
Panelists repeated, throughout the discussions, the risk communication challenges that exist with
any exposure or diagnostic tool. The limits of the state of knowledge need to be communicated as
clearly as possible by laboratories, practitioners, ATSDR, etc. (RB, MG).
6.4 Recommendations
Panelists’ recommendations focused on measures to standardize sampling protocols. The group
agreed that such efforts would improve the overall usability and reliability of testing data. The
group discussed sample collection, handling, and processing procedures. One panelist
recommended considering hair analysis results only if the laboratory documents good practice in
terms of handling and validation protocols (MK). It was also recommended that the
governmental, commercial, and research laboratories pool their experience and help develop
standard protocols (SS). Panelists offered the following specific recommendations:
• Standardize sample collection procedures. Samples should be ordered by a physician,
taken for a defined reason, properly collected, and dealt with according to proper chain of
custody procedures. A determination needs to be made regarding the best location on and
distance from the scalp to test. No consensus was reached on the preferred cutting device.
To avoid metal contamination, some panelists recommend using quartz or plastic or
teflon-coated shears. Others questioned whether it really made that much of a difference.
ATSDR Hair Analysis Panel Discussion
6-6
Most important, everyone agreed, is for the laboratory to demonstrate the extent of
contamination introduced, if any, during sample collection. Lastly, sample handling (chain
of custody) procedures should be the same as those applied to other environmental
samples.
• Collect exposure histories. Several panelists recommended obtaining exposure histories
concurrent with collecting hair samples. Information should be collected for the year prior
to the collection date, although one panelist pointed out that recall bias may likely be a
limiting factor. Histories should consider environmental and treatment exposures. It was
recommended that the questionnaire that has been used by CDC be used as a starting point
or model. Lastly, any such questionnaire should be substance-specific.
• Establish quality assurance protocols. Use quality assurance methods for laboratory
analyses recommended by the World Health Organization (1994). Specifically, (1)
reference samples of the same matrix (hair) with known concentrations of the metal should
be used as standards, (2) reference samples should contain the metal at approximately the
same concentration as the sample, (3) if such reference materials are not available, analysis
of quality-control samples at different laboratories by different analytical methods must be
used, and (4) because results may vary over time and for different metals, results should be
present for the corresponding time periods and metals (SS).
• Require external validation. Require performance evaluations of hair testing laboratories
in the form of proficiency testing (e.g., running reference samples and evaluation of
materials of unknown content). The Center for Toxicology in Quebec occasionally offers a
hair analysis sample for ICP-MS (DP).
• Require documentation. Testing laboratories need to be challenged to make a deliberate
day-to-day effort to demonstrate internal and external validation. Calibration and quality
assurance methods need to be well-documented (DP, MK).
• Encourage targeted analyses. Target testing to the specific element of interest. Testing for
multiple analytes increases uncertainty. Overlapping peaks may lead to the
misinterpretation of results (MK).
• Develop washing protocols. Differing opinions were voiced regarding whether hair
samples should be washed, but the panelists generally agreed that the effects of washing,
when performed, need to be clearly documented by the laboratory. Individual panelist
input is summarized below.
– The determination of whether or not to wash the sample is a substance-specific
decision (SS).
ATSDR Hair Analysis Panel Discussion
6-7
– Insufficient data exist to measure the true effects of washing, so washing adds
another layer of uncertainty when data are interpreted (MK).
– One panelist recommended examining the wash solution when washing (RB), but
others questioned how to interpret the resulting data, fearing that it may add yet
another layer of uncertainty (DP, MK).
6.5 Next Steps To Be Taken by ATSDR
Dr. Susten described ATSDR’s anticipated next steps related to evaluating the utility of hair
analysis. First, a summary report of this panel meeting will be generated and released (the report
will be posted on ATSDR’s Web site). Second, ATSDR will generate a report related to lessons
learned from the panel discussions (and possibly publish it in the open literature). In addition,
internally, the agency plans to do the following:
• Continue to provide education to physicians and other health professionals.
• Develop a generic fact sheet to help health assessors and communities communicate and
understand hair analysis issues.
• Continue to develop substance-specific toxicological profiles. The profiles are an excellent
resource and contain information on biomarkers of exposure. In light of the panel
discussions, additional language may be added regarding hair analysis (e.g., in terms of
limitations, etc.) on a substance-specific basis.
• Develop guidance on hair analysis to support public health assessments and health studies
conducted by the agency. That is, develop criteria for determining when to consider hair
analysis as part of an ATSDR exposure investigation.
These activities will help all of ATSDR’s divisions as well as professionals in the community.
ATSDR Hair Analysis Panel Discussion
7-1
SECTION 7
OBSERVER COMMENTS
On both days of the panel discussions, observers were given the opportunity to provide input on
issues related to the charge questions and panel deliberations. Observer comments received during
the meeting are summarized below, alphabetized by observer’s name. A full list of observers and
their respective positions and affiliations is included in Appendix F. Observers were asked to
provide appropriate references and data to support their statements where possible. Statements
provided without reference are included, but have not been verified or validated by ATSDR or the
panel. In some cases panelists responded to a particular observer comment or question; such
responses are summarized in this section as well.
Observers were also encouraged to provide written comments after the June 12–13, 2001, panel
discussions. Appendix G includes written comments from two individuals.
Erik Auf der Heide
ATSDR
Dr. Auf der Heide commented that considering sensitivity, specificity, and predictive value is as
important as the reference range when interpreting laboratory data.
Sherlita Amler
ATSDR
Dr. Amler, a pediatrician, stressed her observations of over-interpretation and misinterpretation of
hair analysis results.
She noted that a lack of knowledge exists among health care providers in terms of how to use hair
analysis, citing two examples. She described a case of an autistic child with reportedly high levels
ATSDR Hair Analysis Panel Discussion
7-2
of mercury in his hair. The physician presumed that the elevations were due to his immunizations
and ordered chelation in hopes of improving the autism. In another case, the interpretation of hair
analysis results of a Down’s Syndrome child as a dietary insufficiency led to the administration of
high vitamin doses and an unusual diet. (Dr. Clarkson raised the point that misuse or
misinterpretation of laboratory tests is not unique to hair analysis.)
Gary Campbell
ATSDR
Dr. Campbell emphasized the need to clearly define “normal” and “reference” ranges and to
describe how these ranges are developed in the various laboratories. Understanding the meaning
and derivation of such ranges is very important to individuals who need to interpret site-specific
hair analysis results and understanding whether results may be elevated. Further, Dr. Campbell
questioned what is known about possible geographical or regional differences in background
concentrations of various substances in hair.
Robert Jones
CDC
Dr. Jones requested that the panel and ATSDR consider the following:
• Evaluate substances on a species-specific basis, not just on an element basis. Looking at
the form in which elements such as arsenic, mercury, and selenium are present in hair may
help to distinguish exposures due to the form released from a Superfund site from
exposures to a form originating from another source.
• If ATSDR is considering hair analysis in its public health assessments, begin the process of
generating substance- and species-specific quality control reference materials as soon as
possible. Generation of such reference materials can take years.
• Include handling procedures and short- and long-term storage requirements (e.g.,
container and climatic conditions) in any standard protocol.
ATSDR Hair Analysis Panel Discussion
7-3
• Do not standardize hair analysis procedures too highly or you risk stifling innovation by
laboratories. Strict standardization will not guarantee good quality control. Specific
procedures or technologies should not be required as long as the laboratory can
demonstrate the quality of its results. Proficiency systems (daily and longer-term), as
recommended by the Clinical Laboratory Improvement Act (CLIA), are encouraged.
Melody Kawamoto
CDC/National Institute for Occupational Safety and Health
Dr. Kawamoto presented a schematic that integrated many of the concepts and issues being
discussed by the panel (see Figure 7-1). She explained the interface between the many
compartments within the body and how different testing methods help piece exposure information
together. Specifically, Dr. Kawamoto discussed how different methods help assessors identify
potential (environmental media sampling), external (wipes, breathing zone air samples, hair), and
internal (hair, blood, urine) exposures to a particular substance and how that information may be
integrated to evaluate potential health effects. She emphasized the importance of establishing a
framework under which to conduct exposure and health effects evaluations, including clearly
identifying the problem and the hypothesis under which you will proceed, identifying study design
issues, and understanding sampling and analytical issues.
David Mellard
ATSDR
In reference to the arsenic conference held in San Diego in 2000, Dr. Mellard commented on a
study in which a single volunteer showered in arsenic-contaminated water to help better
understand internal versus external contamination. The study revealed that up to a certain level,
no change in arsenic levels in hair were observed. Dr. Mellard suggested that perhaps further
study is worthwhile to see if, for relatively low levels of arsenic in water, hair could be used as a
measure of internal contamination, without worrying about external contamination.
ATSDR Hair Analysis Panel Discussion
7-4
Dr. Kosnett responded with a few words of caution: In vitro experiments have shown that
external absorption is dependent on time. Therefore a single showering episode may not reflect a
longer-term exposure or exposure through bathing. Having reviewed the literature, Dr. Kosnett
indicated that he is not convinced yet that any cut-off point exists at which there is no element of
external uptake of arsenic in hair from bathing.
ATSDR Hair Analysis Panel Discussion
7-5
Figure 7-1. Evaluation and Solution of Environmental and Occupational Health Problems: Critical Analysis
in Practice
1
Model:
Cause-
Effect
?
Source
?
Exposure
?
Effect
Indicators
of
exposure
and effects
Substances
known to
be present
at site
Potential
dose
?
External dose
?
Internal
dose
“Abnor
mality”
?
Disease or
other
health
effect
Possible
detectable
or
measurable
parameters
(examples)
Inventories
of raw
materials,
byproducts
, and final
products
Concentra
-tions in
air, soil,
water,
and
surface
wipe
samples
Personal air
samples,
wipe samples
of skin, hair
analysis;
dosimetry
Concen-
trations in
blood,
urine, and
other body
tissues and
fluids;
dosimetry
Bio-
markers
or other
indica-
tors
Bio-
markers
or other
indicators
Type of
assessment
Document
review
Environmental Biological Biological and other
I
S
S
U
E
S
Model • Hypothesis or problem statement clearly defined
• Scientific plausibility (e.g.,toxicity, biokinetics, relationship between time of exposure and time of
assessment)
• Motives and desired results
• application of scientific methods to research theoretical questions
• application of available scientific knowledge to provide answers to questions from the public
Public
health
criteri
a and
study
design
• Selected parameters to be measured are valid with respect to the model
• Interpretation possible (e.g., dose-response relationship, population norms, intra- and interindividual
variability)
• Relevance of interpretation to the problem statement (e.g., prevention possible) or to questions from
the public (e.g., predictive value, risk communication)
• Feasibility (technical feasibility and cost feasibility)
• Timeliness
• Ethics
Collec
tion
and
handli
ng
• Contamination
• Stability during transport or storage
• Preparation methods (e.g., cleaning, digestion)
Labora
tory
metho
ds
• Validity, reliability, accuracy, precision, sensitivity, specificity
• Quality control (proficiency tests, coefficient of variation)
1
Dr. Kawamoto provided this schematic following the meeting, as a work in progress, as a visual
display of the various concepts presented as part of the panel discussions. It is an expanded
version of a hand-drawn figure presented at the meeting.
ATSDR Hair Analysis Panel Discussion
7-6
David Quig
Doctor’s Data
Day #1
Dr. Quig, from Doctor’s Data (a commercial laboratory), expressed extreme gratitude for being
invited to this meeting and offered his opinion on a variety of topics related to analytical methods
and factors affecting the interpretation of laboratory results:
• As a screening tool, no one laboratory test exists that is absolutely definitive. It is critical
that hair analysis results be looked at in careful consideration of patient symptoms and
exposures. Hair analysis is not a test to end all tests.
• A targeted approach is necessary for certain elements. There is no question, for example,
that chromium is extremely difficult to measure. One laboratory using high-resolution
mass spectrometry is getting closer to being able to measure Cr
6+
in blood. However,
interference problems do not exist for all the elements.
• Hair treatment is an important issue and clearly affects hair analysis results. Dr. Quig has
worked on a study of 150 hair products (pre-published status); the most common
contaminants identified include tin, aluminum, silicone, and phosphorous. Only two
products have been found to contain mercury and arsenic (Denorex and Aquanet), which
could confound hair analysis for these elements.
• Ethnicity/race needs to be factored in when evaluating hair analysis results. For example,
the reference ranges for Caucasians should not be used for African Americans. The basic
profile is very different between the two.
• With respect to growth rates, the difference between the very young and the very old is
significant.
• Distinguishing internal versus external levels is impossible. Some laboratories claim they
have an algorithm for making such distinctions. Any such claim should be seriously
questioned.
• In Dr. Quig’s experience, laboratories do take into account the type of container in which
samples are stored.
ATSDR Hair Analysis Panel Discussion
7-7
• Using hair analysis for an individual can be acceptable and useful—for example, when
tracking occupational exposures of a particular person over time (e.g., a worker exposed
to lead).
• Washing procedures are a critical part of the hair analysis protocol (with the possible
exception of methyl mercury testing). It would not be desirable, for example, to test
unwashed dreadlocks.
• The only time Dr. Quig has seen significantly elevated mercury in hair levels in non-fish-
eating individuals is with dentists exposed occupationally to mercury vapor. In questioning
whether this was internal or external contamination, a comparison of scalp and pubic hair
confirmed equally high levels; this suggested internal exposure. Again, it is critical to look
at hair analysis screening in context of other measurements (e.g., blood).
• As indicated by the panel, it is important to realize that the presence of organic toxins
(e.g., DDT) is not “normal.” It is equally important to recognize that we are all subjected
to exposure to a variety of organic compounds and toxic metals. It is therefore important
to consider multiple exposures.
• Standardization of laboratories is a necessity. The same methods and sensitivities should
be required. It is not surprising that Seidel et al. (2001) found different reference ranges
across the laboratories studied, because the laboratories used different analytical methods
(i.e., ICP-MS versus OES) that have a 1,000-fold difference in the detection limits. This
discrepancy should not be used as a reason for not using hair analysis, but as the impetus
for advocating standard protocols.
Day #2
Dr. Quig provided more comments toward the end of the second day of the meeting. His stated
opinions are summarized below:
• If done correctly, hair analysis can be a useful tool.
• No question exists that gross ineptness has been observed at some commercial
laboratories. The issue of interlaboratory differences is not sufficient reason, however, to
conclude that hair analysis is not of value. It is simply a question of tightening up
sampling/analytical protocols and QA/QC procedures.
ATSDR Hair Analysis Panel Discussion
7-8
• Regarding quality control issues, Doctor’s Data has been pressing for the establishment of
standardized procedures for hair analysis under CLIA and the Health Care Financing
Administration. The fact that procedures are not yet in place is not a reason not to do hair
analysis; it is a matter of the organizations catching up with the needs of the time.
• Regarding washing protocols: A laboratory should produce a reasonable report describing
its washing protocol. The user of the data should look for this information before
interpreting the data.
• A standardized procedure can and should be set for sample collection.
• Statements by panelists regarding the over-interpretation and misuse of hair analysis were
not relevant to the specific charge of this meeting and should not be of concern to
ATSDR.
• Doctor’s Data only accepts hair samples from licensed physicians or for research
purposes. Dr. Quig agreed that hair samples should only be submitted by trained
practitioners.
• Dr. Quig suggested looking at research conducted by Needleman (University of
Pittsburgh) and Masters (Dartmouth) before dismissing the utility of hair analysis for
evaluating lead exposures.
• Sound literature does exist on manganese and aberrant behavior, although the literature is
criticized by the panel. Dr. Quig referenced a follow-up study comparing manganese levels
in prisoners committing violent versus nonviolent crimes. With regards to the symptoms
and the neurotoxicity of manganese, psychological effects range from apathy progressing
to violent reactions and loss of tolerance. The physiology of manganese toxicity is well-
established in the literature. Manganese has a high propensity to bind to myelin pigmented
dopaminergic neurons in the brain.
• Reference ranges are not based exclusively on small data pools (e.g., “n=2”), as suggested
during some of the panel discussions. Available reference ranges are based on 28 years of
doing hair analysis. As methods improve, so will reference ranges. Data sets are expanding
to include documentation of variations in levels of elements between Caucasians and
African Americans, as well as transcontinental differences.
Barry Sample
Quest Diagnostics
ATSDR Hair Analysis Panel Discussion
7-9
Dr. Sample speculated on the possible value of measuring wash solutions as well as washed hair in
attempts to further distinguish between internal and external exposures. Wash solution may
provide a better sense of external levels and the hair may provide a better indication of the total
internal burden. At a minimum, Dr. Sample suggested incorporating wash evaluation into any
standard protocol.
Based on his experience looking at drugs, Dr. Sample acknowledged that data may not exist to
set the “normal range.” In order to do so, one needs to understand the different rates and methods
of incorporation into the hair. He suggested that there may be some value, in an occupational
setting, in developing an individual reference range.
In response, Dr. Kosnett commented that workers may not be the best population to study for
normal ranges because of the potential for external exposures in various work places. Dr. Seidel
noted that further research is needed into the utility of studying wash water. Studies suggesting
that easily removed fractions represent exogenous sources and the not so easily removed fraction
represents endogenous sources have been disproved.
Michael Schaffer
Pyschemedics Corporation
Day #1
Dr. Schaffer, a trained industrial toxicologist with an interest in criminal justice and forensics,
explained that Pyschemedics performs hair analysis as part of workplace drug testing. He asked
participants to keep an open mind and consider the science of hair analysis very carefully.
Knowledge gained from the last 10 years of testing hair for drugs of abuse can, he said, be used to
enhance the knowledge base for using hair analysis for environmental/public health evaluations.
He stressed that his experience in the drug testing arena has revealed that hair analysis is not
ATSDR Hair Analysis Panel Discussion
5
Dr. Baratz clarified that his purpose in presenting the Ditton paper was to summarize some of the
key aspects and possible pitfalls of hair analysis. Dr. Baratz noted that the author, a chemist, has done
studies on drugs of abuse and has shown the validity of hair analysis for testing drugs of abuse.
7-10
totally unreliable. Good science and good analyses have supported legal cases. If the proper
analytical tools and washing procedures are used, valid interpretations can be made.
Dr. Schaffer recognizes that drugs of abuse are different than trace metals. Working with mass
spectrometry, metabolite profiling has helped identify uniquely internal measures of the substance
of concern. It has taken 10 years, but such tools are now available.
Dr. Schaffer stressed that hair offers a unique matrix, recognizing that there is much that is not
known or understood. In time, he feels, hair analysis will likely provide a lot of useful information.
Day #2
Dr. Schaffer expressed concern that some of the statements made during the panel discussions
could be misinterpreted or used inappropriately. Specifically, he wanted to make certain that
caveats were provided with panel conclusion statements so that it is clear that hair analysis for
substances of abuse is appropriate and based on good science; the conclusions drawn by the panel
should apply to environmental contaminants only.
Dr. Schaffer also responded directly to Dr. Baratz’s overview of the Ditton paper.
5
He took
exception to the implication that hair analysis may not be suitable for testing drugs of abuse. He
stated that conducting hair testing with the proper safeguards is defensible and has been upheld by
the courts. He noted that no hair color or ethnicity bias exists. In vitro studies have shown
incorporation of drugs in different types of hair, but those drugs can be removed by washing as
quickly as they are bound to hair. The Department of Health and Human Services (Substance
Abuse/Mental Health Services Administration) is currently writing draft guidelines for the
ATSDR Hair Analysis Panel Discussion
7-11
incorporation of hair analysis into the federal workplace drug testing program. A pilot proficiency
survey is also available to help address quality control issues; the model is urine drug testing.
Subsequent to the June 12–13, 2001, panel discussions, Dr. Schaffer submitted additional
comments and supporting literature. He provided (1) a partial listing of those cases demonstrating
judicial acceptance of the Psychemedics hair analysis method, (2) information on hair testing and
racial or color bias, and (3) information on the effectiveness of Psychemedics’ washing procedures
for ruling out external contamination. (See Appendix G.)
Margaret Schonbeck
Colorado Department of Public Health and Environment
Ms. Schonbeck questioned whether hair analysis would be a valid consideration at an arsenic
exposure site (soil pica/soil ingestion) where urine sampling is already planned.
Dr. Kosnett commented that a hair assay could reveal the potential for exposure, but that
environmental and urine data will have already provided that information. It is not likely that hair
analysis would provide additional insight. Dr. Baratz re-emphasized that one must examine the
clinical utility before considering hair analysis. Does it have any predictive value? Without
symptom or disease history, or unless you have a quantifiable dose-response relationship, hair
analysis data will not help. Dr. Baratz expressed concern that collecting hair samples as another
means of documenting exposure will only muddy the waters. Dr. Seidel suggested collecting,
analyzing, and archiving the data, but being clear with the community up front what the data can
and cannot be used for. Dr. White emphasized the distinction between medicine and public health,
which can sometimes cause confusion and tension in the community. That is, medicine is looking
at the individual and treatment options, while public health is looking at populations and possible
risk factors.
ATSDR Hair Analysis Panel Discussion
7-12
Anthony Suruda
Association of Occupational Environmental Clinics
Rocky Mountain Center for Occupational and Environmental Health
Dr. Suruda questioned whether nails are more susceptible to external contamination by metals
than hair. In response, Dr. Kosnett noted that, in some forensic investigations, the distal portions
of nails have shown correlation with poisoning. Some studies have investigated whether the inner
surface of the nail may be less likely to contain elevated levels of arsenic as a result of external
contamination. Study findings suggest that external contamination of nails is an issue as it is in
hair. For example, a study that measured arsenic in nails over time following arsenic ingestion
revealed the following: (1) elevated levels of arsenic were measured in distal segments of
unscraped nails (believed to be deposited by sweat); (2) scraped nails during the same period did
not reveal elevated levels; and (3) samples of scraped nails taken later in time showed elevated
arsenic levels (as a result of the ingestion episode). As with hair, it is questionable whether
methods exist to clearly distinguish between externally and internally deposited contamination.
Dr. Suruda indicated that he was requested to evaluate an individual with peripheral neuropathy 9
months after possible exposures to lead and arsenic. Total arsenic urinalysis had been performed
closer to the time of exposure, but not a fractionated analysis. To evaluate past exposures, a
toenail sample was taken down to the growth plate, which was negative. These results were used
to conclude that the individual had not been exposed to arsenic within the past year.
Dr. Suruda noted that the charge to the panel was to examine aspects of hair analysis related to
public health assessments. Dr. Suruda commented that he is more often faced with questions from
individuals (practitioners, community members) looking for assistance in interpreting hair analysis
results. He expressed hope that the panel and ATSDR will consider the utility of hair analysis in
the assessment of public health as well as for individual assessment. Dr. Suruda noted that
ATSDR’s toxicological profiles and other agency documents have great credibility within the
scientific community and that he looks forward to further guidance (e.g., biological monitoring
ATSDR Hair Analysis Panel Discussion
7-13
guidelines) to assist in his evaluations. Even if all the answers are not available, Dr. Suruda said,
hair analysis should be ranked with other methods of monitoring (e.g, blood, urine).
Regarding research needs, Dr. Suruda indicated the need for a population-based study on how
hair analysis is used and what impact it has had. Questions to consider include: Can it be used to
identify poisoned individuals? How many people are unnecessarily alarmed or mistreated on the
basis of hair analysis? What type of reports do practitioners receive on hair analysis? Dr. Suruda
expressed concern regarding what he referred to as “junk science.” For example, he pointed to a
laboratory report that indicated “lead is slightly above detection limit” and that the “zinc to
mercury ratio is extremely high.” The report indicated that these ratios do not indicate disease;
however, it also indicated that research has shown that this “will eventually lead to other
disturbances in metabolic function.” Physicians and other practitioners need to recognize that they
do not often know what results mean and should be cautious in what they report.
ATSDR Hair Analysis Panel Discussion
8-1
SECTION 8
REFERENCES
The following papers were reviewed by the panelists prior to the meeting for their consideration
when reviewing the charge questions.
Hopps H. The biologic bases for using hair and nail analyses for trace elements. Sci Total
Environ. 1977; 7:71-89.
Miekeley N, Dias Carneiro MTW, Porto da Silveira CL. How reliable are human hair
reference intervals for trace elements? Sci Total Environ. 1998; 218:9-17.
Seidel S, Kreutzer R, Smith D, McNeel S, Gilliss D. Assessment of commercial
laboratories performing hair mineral analysis. JAMA. 2001 Jan 3; 285(1):67-72.
Sky-Peck H. Distribution of trace elements in human hair. Clin Physiol Biochem. 1990;
8:70-80.
Steindel S, Howanitz P. The uncertainty of hair analysis for trace metals. JAMA. 2001 Jan
3; 285(1):83-5. Editorial.
Wennig R. Potential problems with the interpretation of hair analysis results. Forensic Sci
Int. 2000 Jan 10; 107(1-3):5-12. Review.
Yoshinaga J, Imai H, Nakazawa M, Suzuki T. Lack of significantly positive correlations
between elemental concentrations in hair and in organs. Sci Total Environ. 1990; 99:125-
35.
The next set of references represents those cited in the main text of this report through direct
reference during the meeting or provided after the meeting to support statements made during the
meeting.
Anderson RA. 1997. Chromium as an essential nutrient for humans. Regulatory
Toxicology and Pharmacology. 1997; 26:S35-S41.
ATSDR Hair Analysis Panel Discussion
8-2
Anderson RA, Kozlovsky AS. 1985. Chromium intake, absorption, and excretion of
sumbects consuming self-selected diets. Am J Clin Nutr. 1985; 41:1177-83.
Bader M, Dietz MC, Ihrig A, Triebeg G. 1999. Biomonitoring of manganese in blood,
urine and axillary hair following low-dose exposure during the manufacture of dry cell
batteries. Int. Arch. Occup. Environ. Health. 1999; 72:521-27.
CDC. 2001a. Blood and hair mercury levels in young children and women of childbearing
age-United States, 1999. MMWR Weekly. 2001 Mar 2; 50(8):140-3.
CDC. 2001b. National Report on Human Exposure to Environmental Chemicals. NCEH
Publication 01-0379. http://www.cdc.gov/nceh/dls/report
Chittleborough G. 1980. A chemist’s view of the analysis of human hair for trace
elements. Sci Total Environ. 1980; 14:53-75.
Curry AS, Pounds CA. 1977. Arsenic in hair. J. For. Sci. Soc. 1977; 17:37-44.
DeFlora S, Wetterhahn RF. 1989. Mechanisms of chromium metabolism and genotoxicity.
Life Chem Reports. 1989; 7:169-244.
DiPietro ES, Phillips DL, Paschal DC, Neese JW. 1989. Determination of trace elements
in human hair. Reference intervals for 28 elements in nonoccupationally exposed adults in
the US and effects of hair treatments. Biol Trace Elem Res. 1989 Oct; 22(1):83-100.
Donaldson RM, Jr., Barreras RF. 1966. Intestinal absorption of trace quantities of
chromium. J Lab Clin Med. 1966; 68:484-93.
Harkey MR. 1993. Anatomy and physiology of hair. Forensic Sci Int. 1993 Dec;
63(1-3):9-18.
Harrington, JM et al. 1978. A survey of a population exposed to high concentrations of
arsenic in well water in Fairbanks, Alaska. Am. J. Epid. 1978; 108(5):377-85.
Hunter D. 1974. The Diseases of Occupations. 5
th
Edition. Boston: Little, Brown. 1974
Jankovic SM, Jankovic SV. The control of hair growth. Dermatology Online Journal.
4(1):2. http://dermatology.cdlib.org/DOJvol4num1/original/jankovi.html
Kerger BD, Richter RO, Chute SM, Dodge DG, Overman SK, Liang L, Finley BL,
Paustenbach DJ. 1996. Refined exposure assessment for ingestion of tapwater
ATSDR Hair Analysis Panel Discussion
contaminated with hexavalent chromium: consideration of exogenous and endogenous
reducing agents. Journal of Exposure Anal. and Environ. Epid. 1996; 6(2):163-79.
Leslie ACD, Smith H. 1978. Napolean Bonaparte’s exposure to arsenic during 1816. Arch
Toxicol. 1978; 41:163-7.
Mertz W. 1969. Chromium occurrence and function in biological systems. Physiol Rev.
1969; 49(2):165-239.
Myers RJ, Hamilton. 1951. Regeneration and rate of growth of hairs in man. Ann NY
Acad Sci. 1951; 27(53):562-8.
National Research Council (NRC). 1989. Recommended Dietary Allowances.
Washington, DC: National Academy of Sciences. 1989.
Paschal DC, DiPietro ES, Phillips DL, Gunter EW. 1989. Age dependence of metals in
hair in a selected U.S. population. Environ Res. 1989 Feb; 48(1):17-28.
Schroeder HA. 1968. The role of chromium in mammalian nutrition. Am J Clin Nutr.
1968; 21(3):230-44.
Smith H. 1964. The interpretation of the arsenic content in human hair. J. For. Sci. Soc.
1964; 4:192-99.
U.S. EPA. 2001. Integrated Risk Information System. Methyl mercury (last significant
revision: 7/21/01). http://www.epa.gov/iris/subst/0073.htm
Van den Berg AJ et al. 1968. Arsenic content of human hair after washing as determined
by activation analysis, in DeVoe JR [ed.] Modern Trends in Activation Analysis, Vol. I.
Washington, DC: NBS. 1968; pp. 272-82.
World Health Organization (WHO). 1994. Biological Monitoring of Metals. Geneva:
WHO. 1994.
See also the bibliography of hair analysis references provided in Appendix D.
