Hair Analysis Panel Discussion: Section 2.3

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Section 2
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 (Cr⁶⁺) 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, Cr³⁺ 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 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 Cr⁶⁺ were received via inhalation. Cr³⁺ 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 Cr⁶⁺, ingested Cr⁶⁺ is reduced to Cr³⁺ within minutes (Kerger et al. 1996). As a result, a person can tolerate ingestion of 50–100 milligrams of Cr6+ 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 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.

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