Dental amalgam and urinary mercury concentrations: a descriptive study

BMC Oral Health. 2013 Sep 9;13:44. doi: 10.1186/1472-6831-13-44.


Background: Dental amalgam is a source of elemental and inorganic mercury. The safety of dental amalgam in individuals remains a controversial issue. Urinary mercury concentrations are used to assess chronic exposure to elemental mercury. At present, there are no indications of mercury-associated adverse effects at levels below 5 μg Hg/g creatinine (Cr) or 7 μg Hg/L (urine). The purpose of the present study is to determine the overall urinary mercury level in the Canadian general population in relation to the number of dental amalgam surfaces.

Methods: Data come from the 2007/09 Canadian Health Measures Survey, which measured urinary mercury concentrations in a nationally representative sample of 5,418 Canadians aged 6-79 years. Urinary mercury concentrations were stratified by sex, age, and number of dental amalgam surfaces.

Results: The overall mean urinary mercury concentration varied between 0.12 μg Hg/L and 0.31 μg Hg/L or 0.13 μg Hg/g Cr and 0.40 μg Hg/g Cr. In general, females showed slightly higher mean urinary mercury levels than men. The overall 95th percentile was 2.95 μg Hg/L, the 99th percentile was 7.34E μg Hg/L, and the 99.9th percentile was 17.45 μg Hg/L. Expressed as μg Hg/g Cr, the overall 95th percentile was 2.57 μg Hg/g Cr, the 99th percentile was 5.65 μg Hg/g Cr, and the 99.9th percentiles was 12.14 μg Hg/g Cr. Overall, 98.2% of participants had urinary mercury levels below 7 μg Hg/L and 97.7% had urinary mercury levels below 5 μg Hg/g Cr. All data are estimates for the Canadian population. The estimates followed by the letter "E" should be interpreted with caution due to high sampling variability (coefficient of variation 16.6%-33.3%).

Conclusions: The mean urinary mercury concentrations in the general Canadian population are significantly lower than the values considered to pose any risks for health.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Body Burden
  • Canada
  • Child
  • Dental Amalgam*
  • Environmental Exposure
  • Female
  • Humans
  • Male
  • Mercury / urine*
  • Middle Aged
  • Young Adult


  • Dental Amalgam
  • Mercury