Hair-to-blood ratio and biological half-life of mercury: experimental study of methylmercury exposure through fish consumption in humans

J Toxicol Sci. 2012 Feb;37(1):123-30. doi: 10.2131/jts.37.123.


The hair-to-blood ratio and biological half-life of methylmercury in a one-compartment model seem to differ between past and recent studies. To reevaluate them, 27 healthy volunteers were exposed to methylmercury at the provisional tolerable weekly intake (3.4 µg/kg body weight/week) for adults through fish consumption for 14 weeks, followed by a 15-week washout period after the cessation of exposure. Blood was collected every 1 or 2 weeks, and hair was cut every 4 weeks. Total mercury (T-Hg) concentrations were analyzed in blood and hair. The T-Hg levels of blood and hair changed with time (p < 0.001). The mean concentrations increased from 6.7 ng/g at week 0 to 26.9 ng/g at week 14 in blood, and from 2.3 to 8.8 µg/g in hair. The mean hair-to-blood ratio after the adjustment for the time lag from blood to hair was 344 ± 54 (S.D.) for the entire period. The half-lives of T-Hg were calculated from raw data to be 94 ± 23 days for blood and 102 ± 31 days for hair, but the half-lives recalculated after subtracting the background levels from the raw data were 57 ± 18 and 64 ± 22 days, respectively. In conclusion, the hair-to-blood ratio of methylmercury, based on past studies, appears to be underestimated in light of recent studies. The crude half-life may be preferred rather than the recalculated one because of the practicability and uncertainties of the background level, though the latter half-life may approximate the conventional one.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Animals
  • Female
  • Fishes*
  • Food Contamination / analysis
  • Hair / chemistry*
  • Half-Life
  • Humans
  • Male
  • Mercury / analysis*
  • Mercury / blood
  • Methylmercury Compounds / pharmacokinetics*
  • Water Pollutants, Chemical / pharmacokinetics*
  • Young Adult


  • Methylmercury Compounds
  • Water Pollutants, Chemical
  • Mercury