Hair Analysis Panel Discussion:
Section: Appendix G, Buck Grissom's Comments
Error processing SSI fileAppendix G
Post-Meeting Observer Comments
Buck Grissom, Ph.D.
Health Science Administrator (Biomedical Sciences)
National Institute of Environmental Health Sciences
Comments Concerning the Interpretation of Hair Analysis
I have used only data from hair analysis to help determine when an exposure occurred (see Item 1). There are too many variables to use hair data for any other purpose (see Item 2). I have commented on several instances in which hair data had been misused/misinterpreted by citizens and health care providers. Example: I received a call from a concerned parent. His son's symptoms were as follows: dizziness, poor skin color, poor mental acuity, and blackouts (petit mal seizure like symptoms). A physician had analyzed his son's hair for metals and recommended chelation therapy at a cost of $6,000. His son's hair levels were within levels typically reported for control groups in hair analysis studies. Neither a source nor a pathway had been identified. No one else was in the area was having similar health problems. Their water was not contaminated. I told the parent to get a second opinion. Additional testing was needed to determine his son's health problems; hair analysis was inadequate. Moreover, chelation therapy is not risk free. I suggested the closest Association of Occupational Environmental Clinics clinic or a pediatrician trained to diagnose neurological symptoms before proceeding with chelation therapy.
General Questions (page 2)
| 1. | When is it appropriate to consider hair analysis in assessing human exposures to environmental contaminants? |
COMMENT: If a source and pathway have been identified, hair analysis may provide information concerning episodic exposures (i.e., frequency and duration of exposure).
| 2. | When is it inappropriate to consider hair analysis in assessing human exposures to environmental contaminants? |
COMMENT: Information concerning sources, pathways, etc. (i.e., is exposure plausible), of interest to ATSDR is required before attempting to interpret hair data. Interpretation of data from hair analysis in the absence of environmental data is conjectural.
| 3. | 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 data gaps? |
COMMENT: Internal sources of metals detected in hair need to be distinguished from external sources.
COMMENT: External sources of arsenic need to be distinguished
(e.g., air, food, water, medicinals, and hair dyes). Is there a
hazardous waste site involved?
COMMENT: Analytical methods that result in elimination of intra-
and inter-laboratory data variability are needed.
Specific Questions
| 4. | Topic #2 (page 3) |
| • | Factors Influencing the Interpretation of Analytical Results. |
COMMENT: This section lists many of the factors that confound interpretation of hair data. I agree with Dr. Baratz's comment: I do not want information that I cannot interpret. Even under the best circumstances, hair data are exceedingly difficult to interpret. In cases where hair levels exceed levels expected in a population, additional information is needed.
| 5. | Topic #3, Toxicologic Considerations
(page 4) |
| • | Is information available defining "normal" ranges of chemical concentrations in hair that have physiological and health significance? |
COMMENT: Terms such as standard or normal hair levels of metals or reference ranges for metal levels in hair need to be carefully defined—i.e., what constitutes normal? All reference values for hair need to be representative of the population being evaluated. For example, groundwater levels of arsenic (e.g., 100 ppb) have been reported to be elevated in some areas of Utah, Michigan, and Maine. Hair levels of arsenic in these areas are likely to be greater than hair levels in areas with low levels of arsenic in groundwater (e.g., 2 ppb).
COMMENT: What do hair levels above a reference value mean? How will hair data be interpreted? Reference values are frequently used for purposes for which they were not intended. A law firm sent a letter to the U.S. EPA citing the CDC lead guidance as a basis for not conducting an environmental investigation requested by EPA. The letter stated that the blood lead levels in the community were not above 20 microgams per deciliter (µg/dL) and did not consistently exceed 15 µg/dL; therefore, an environmental investigation was not needed.
