How reliable are human hair reference intervals for trace elements?

Area of Science:

• Environmental Science
• Analytical Chemistry
• Toxicology

Background:

• Scalp hair analysis is crucial for monitoring environmental exposure and nutritional status.
• Existing reference intervals for hair elements are often based on less sensitive analytical techniques.
• Discrepancies exist between established reference intervals and new data, necessitating re-evaluation.

Purpose of the Study:

• To determine major and trace element concentrations in scalp hair using ICP-MS.
• To establish preliminary reference intervals for elements in a Rio de Janeiro population.
• To compare ICP-MS results with data from ICP-AES and highlight limitations of the latter.

Main Methods:

• Inductively coupled plasma mass spectrometry (ICP-MS) was employed for elemental analysis.
• Scalp hair samples from 1091 individuals in Rio de Janeiro were analyzed.
• Detection limits and interlaboratory comparison data were used to assess analytical methods.

Main Results:

• ICP-MS determined concentrations for major and trace elements, including Boron, Vanadium, Cobalt, Germanium, Molybdenum, Gold, Arsenic, Selenium, Antimony, Thorium, Calcium, and Magnesium.
• Calculated reference intervals showed significant discrepancies with previously published data from laboratories using ICP-AES.
• ICP-AES demonstrated limitations in routine hair analysis compared to ICP-MS, particularly regarding detection limits.

Conclusions:

• Published reference intervals for hair elements should be used with caution due to potential inaccuracies.
• There is an urgent need to revise existing reference intervals using reliable ICP-MS data.
• ICP-MS offers superior sensitivity and accuracy for routine hair elemental analysis.