title: Determination of dioxins in human hair: Estimation of external and internal exposure to dioxins.
abstract: OBJECTIVE
  To clarify the origin of dioxin and related compounds (dioxins) in human hair, we determined the amounts of adsorbed dioxins in human hair, and the distribution of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in rats.
  
  
  METHODS
  Human hair specimens, packed in a glass column, were exposed to ambient air that was introduced into the column with an air pump for 24 h. Rats were administered TCDD by gavage at doses of 0.2, 0.8, and 1.6 μg/kg body weight. Four weeks after TCDD administration, hair from the back, serum, and adipose tissue were removed under diethyl ether anesthesia. The amounts of dioxins in these samples were analyzed by high resolution gas chromatography with mass spectroscopy.
  
  
  RESULTS
  Exposure of the hair specimens to ambient air for one day increased the total toxic equivalent (TEQ) value by 51%. In TCDD-treated rats, the amount of TCDD in hair increased in a dose-dependent manner, and showed a significant positive correlation with that in adipose tissue.
  
  
  CONCLUSIONS
  Human hair was found to retain dioxins by both internal and external exposure, and the contribution of external exposure was estimated to be about 40% of the TEQ.
authors: Environmental Health Sciences Division, National Institute for Environmental Studies (NIES), Tsukuba, Japan, miyabar@gipac.shinshu-u.ac.jp.
authors: Yuichi
authors: Y
authors: Miyabara
authors: Noriko
authors: N
authors: Nishimura
authors: Chiharu
authors: C
authors: Tohyama