Mercury And Health

There is no denying that mercury is highly toxic to humans, with the World Health Organisation stating that there is no safe levels of mercury exposure.

Please read through this page to understand what the science tells us about the dangers of mercury to human health.

The Dangers Of Dental Mercury

Mercury from dental amalgam fillings is one of the main sources of mercury exposure in humans, with evidence suggesting that mercury is constantly released into the body from dental amalgam.1 The dental industry is quick to imply that amalgam fillings are 'silver', referring to the colour rather than the chemical composition - which is usually about 50% liquid mercury.2

Dental amalgam manufacturers clearly recognise the risks of dental amalgam - with material safety data sheets stating "toxic if inhaled", "product contains mercury, a chemical known to the State of California to cause birth defects or other reproductive harm", "fatal if inhaled", "may damage the unborn child" and "causes damage to organs through prolonged or repeated exposure". 2

These risks are almost never communicated to the patient, raising ethical issues surrounding informed consent - with the dental industry preferring to deny what the science clearly states - dental amalgam is dangerous.

Dentists are regularly taught in dental school that mercury is trapped within the chemical structure of the amalgam and will not leak - harming their patients. This claim has been proven false by autopsy studies and visualisations using atomic absorption.

Research has found that there is a strong correlation between the number of amalgam fillings and mercury levels in the body, with approximately 2-5 times more mercury in the blood and urine of living individuals with dental amalgams than those without.1 Autopsy studies found up to 12 times more mercury in amalgam bearers than those without amalgam, with mercury being found in many types of bodily tissues.3 The studies have concluded that dental amalgam is responsible for at least 60-95% of mercury deposits in human tissues.1 Individuals with more than 12 amalgam fillings were found to have mercury levels in the brain well above what is considered to be neurotoxic.3

Saliva methylmercury levels were found to be three times higher on average for those with dental amalgams, even though fish consumption was identical to the control group without amalgams.4 This shows that mercury leaking from dental amalgams is readily converted into methylmercury by bacteria in the mouth and in the gastrointestinal tract. Mercury vapour can even be measured in the breath of those with dental amalgams, along with both inorganic mercury and methylmercury in saliva samples. 4

We recommend that you watch this video to see how much mercury vapour is released from an amalgam filling normally, and during dental procedures.

How Mercury Damages Us

Mercury exposure can cause cognitive damage, permanent damage to the central nervous system, kidney and heart disease, infertility, and respiratory, digestive and immune problems.5 Extreme mercury exposure leads to Minamata Disease - symptoms include numbness, muscle weakness, loss of peripheral vision, damage to hearing and speech, insanity, paralysis, coma, and death.

Mercury readily concentrates in the body, preferring fatty tissues like the brain, nervous system and kidneys. Because mercury concentrates in this way it is difficult to measure mercury toxicity with simple tests like urine and blood. These tests are indicative of mercury exposure but not indicative of the extent of the mercury exposure. For this reason, combined with wide ranging symptoms - mercury poisoning is often difficult to diagnose.

Mercury Harming Children

It is common scientific knowledge that mercury is especially harmful to young children, pregnant women and women of child bearing age. The neurotoxicity of mercury can cause severe birth defects along with developmental and learning disorders.5

In Australia, the National Health & Medical Research Council (NHMRC) recommends that dental amalgam is not used in these mercury sensitive demographics. Research has found mercury levels of up 1000 times higher than what is needed to cause damage to axons in brain tissue of infants whose mothers had dental amalgams.6 , 7 Mercury is able to cross the placental barrier, and concentrates in the foetus as it develops.8 Mercury also passes into breast milk where it can again harm the vulnerable infant.9 Methylmercury levels are moderately correlated to increased mid-term abortions and decreased fertility, indicating that mercury toxicity may be a significant factor for parents struggling with fertility issues.9

For children exposed to mercury in utero - the prognosis is quite poor. Research has found symptoms can include mental retardation, misalignment of the eyes, poor muscle coordination, speech impediments, deformed limbs, epileptic attacks, and growth disorders. 10 Animals studies have determined that there is higher mercury concentration in fetal brain tissue relative to the mother's brain tissue - suggesting that mercury concentrates in the foetus during development.11 For this reason, it is of critical importance to limit all mercury exposure for pregnant women and women of child bearing age.

A Summary Of Mercury & Health

Mercury is undeniably dangerous to human health. Exposure to mercury must be minimised - and this can only be done by stopping human activities that directly expose us to mercury.

The key points are:

  • Mercury is extremely toxic to humans - adults and children alike.
  • Children are more vulnerable to harm from mercury exposure, which can also happen in utero.
  • The dental industry is a major culprit when it comes to exposing people to toxic levels of mercury.
  • Dental amalgam is not safe for anyone.
  • The only safe level of mercury exposure is zero.


  1. Mutter, J. (2011). Is dental amalgam safe for humans? The opinion of the scientific committee of the European Commission. Journal Of Occupational Medicine and Toxicology, 6:2.
  2. Material Safety Data Sheet
  3. Guzzi G, Grandi M, Cattaneo C, Calza S, Minoia C, Ronchi A, Gatti A, Severi G. (2006). Dental amalgam and mercury levels in autopsy tissues: food for thought. Am J Forensic Med Pathol 2006, 27:42-45.
  4. Leistevuo J, Leistevuo T, Helenius H, Pyy L, Osterblad M, Huovinen P, Tenovuo J. (2001). Dental amalgam fillings and the amount of organic mercury in human saliva. Caries Res, 35:163-166.
  5. World Health Organisation 2013, ‘Mercury and Health’, Factsheet No361.
  6. Leong CCW, Syed NI, Lorscheider FL: Retrograde degeneration of neurite membrane structural integrity of nerve growth cones following in vitro exposure to mercury. Neuro Report 2001, 12:733-737.
  7. Drasch G, Schupp I, Hofl H, Reinke R, Roider G: Mercury burden of human fetal and infant tissues. Eur J Ped 1994, 153:607-610.
  8. Zahir F, Rizwi SJ, Haq SK, Khan RH: Low dose mercury toxicity and human health. Environ Toxicol Pharmacol 2005, 20:351-360.
  9. Oskarsson A, Schultz A, Skerfving S, Hallen IP, Ohlin B, Lagerkvist BJ: Total and inorganic mercury in breast milk in relation to fish consumption and amalgam in lactating women. Arch Environ Health 1996, 51:234-241.
  10. Rice, K. M., Walker, E. M., Wu, M., Gillette, C., & Blough, E. R. (2014). Environmental Mercury and Its Toxic Effects. Journal of Preventive Medicine and Public Health, 47(2), 74–83.
  11. Harada M, Nakachi S, Cheu T, Hamada H, Ono Y, Tsuda T, et al. Monitoring of mercury pollution in Tanzania: relation between head hair mercury and health. Sci Total Environ. 1999;227(2-3):249–256.
  12. Meacham CA, Freudenrich TM, Anderson WL, Sui L, Lyons-Darden T, Barone S, Jr, et al. Accumulation of methylmercury or polychlorinated biphenyls in in vitro models of rat neuronal tissue. Toxicol Appl Pharmacol. 2005;205(2):177–187.