Exposure of hairdressers to ortho- and meta-toluidine in hair dyes

Occup Environ Med. 2015 Jan;72(1):57-63. doi: 10.1136/oemed-2013-101960. Epub 2014 Jun 9.

Abstract

Background: Carcinogenic aromatic amines derived from hair dyes have recently received new attention. One of these is ortho (o)-toluidine, which is classified as carcinogenic to humans.

Objectives: To clarify exposure of hairdressers to potentially carcinogenic aromatic amines, including o-toluidine.

Methods: We measured eight potentially carcinogenic aromatic amines in the blood of 295 hairdressers, 32 users of hair dyes and 60 controls. The study was restricted to female non-smokers. Lifestyle data were collected for all participants using self-administered questionnaires. Blood samples were taken for analysis of ortho-, meta (m)- and para (p)-toluidine; 2-, 3- and 4-ethylaniline, 2,3- and 3,4-dimethylaniline as haemoglobin adducts. The samples were analysed with gas chromatography-tandem mass spectrometry.

Results: Generally, adduct concentrations were in the range of 0-200 pg/g haemoglobin. A comparison of the adduct concentrations found in hairdressers, consumers and controls showed no statistically significant differences. However, for hairdressers, o- and m-toluidine concentrations increased significantly with the weekly number of hair waving (p=0.020) and permanent hair dyeing treatments (p=0.026), respectively. o-Toluidine and m-Toluidine concentrations also tended (p=0.076 and 0.080, respectively) to increase with the frequency of light-colour permanent hair dye treatments.

Conclusions: Hairdressers who use light-colour permanent hair dyes, other permanent hair dyes and hair waving treatments seem to be exposed to o- and m-toluidine as indicated by associations with the number of treatments performed. Analyses of hair waving and hair dye products should be performed to identify the possible sources of exposure to o- and m-toluidine.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aniline Compounds / blood
  • Barbering*
  • Carcinogens / analysis
  • Female
  • Gas Chromatography-Mass Spectrometry
  • Hair Dyes / chemistry*
  • Hair Dyes / metabolism
  • Hemoglobins / metabolism*
  • Humans
  • Middle Aged
  • Occupational Exposure / analysis*
  • Toluidines / blood*

Substances

  • Aniline Compounds
  • Carcinogens
  • Hair Dyes
  • Hemoglobins
  • Toluidines
  • 3-toluidine
  • 2-toluidine
  • 2-ethylaniline
  • 4-toluidine
  • 4-ethylaniline
  • 3,4-xylidine
  • 3-ethylaniline
  • 2,3-dimethylaniline