Dental Amalgam Fillings are the Number One Source of Mercury Found in People.
Such Exposure Exceeds Government Health Standards for Inorganic Mercury (Vapor).
By B. Windham
Government agency and private medical studies find that the number one source of mercury found in people is from dental amalgam fillings (refs 2-18). Exposure from fillings amounts to from 50 to 90 percent of the exposure, with the average being about 80% of total exposure (refs 5-9 and 12-15). These studies find that mercury amalgams are unstable due to mercury's low vapor pressure and galvanic action, and leak mercury vapor continuously into the lungs and saliva at levels exceeding health standards. Mercury exposure to most people with amalgam fillings was found to exceed various government health standards and levels found to cause adverse health effects.
The U.S. Environmental Protection Agency (EPA) mercury health standard (ref 1) for elemental mercury exposure (vapor) is 0.3 micrograms per cubic meter of air (0.3 ug/M3). For the average adult breathing 16 M3 of air per day (ref 2), this amounts to an exposure of 5 micrograms (ug) per day. The corresponding tolerable daily exposure developed in a report for the Canadian Health Agency, Health Canada, is .014 ug/kg body weight or 1 ug/day for average adult (ref 2).
The U.S. Agency for Toxic Substances and Disease Registry (ASTDR) standard (MRL) for acute inhalation exposure to mercury vapor is 0.02 micrograms Hg/m3, which translates to approx. 1.2 ug/day for the average adult. The ASTDR MRL for chronic inhalation exposure is 0.014 ug/m3. This translates to approx. .004 ug/kg of body weight or 0.3 ug/day for an average adult (ref 4).
The range of mercury exposure levels found in people with amalgam fillings by the World Health Organization Scientific Panel on Mercury was 3 to 70 micrograms per day (ref 3), with other medical studies finding up to 190 ug/day in gum chewers or people who grind their teeth (refs 6,11,and16). The average exposure was above 10 ug/day (refs 3-18). The average mercury exposure for a Canadian adult with amalgam fillings was found in the Health Canada study to be 9 ug/day (ref 2).
Common levels found in persons with amalgam fillings are as much as 100 times the ASTDR MRLs, over 10 times the Health Canada TDE, and more than the EPA health standard for mercury vapor. Thus persons with amalgam fillings who have levels of intra-oral mercury vapor and body exposure levels higher than the level are considered to have significant health risk.
The studies found that total mercury intake is proportional to the number and extent of amalgam surfaces, but other factors such as chewing gum and drinking hot liquids influence the intake significantly increasing exposure as much as 500%. Vapor emissions range up to 100 ug/M3, and are much higher after chewing (ref 18). Approximately 40% of those having amalgam fillings tested in a large German study had ingested mercury levels exceeding the WHO mercury standard of 43 ug/day (ref 17). A World Health Organization Scientific Panel concluded that a safe level of mercury exposure below which no adverse effects occur has never been established (ref 3).
References:
(1) U.S. Environmental Protection Agency (EPA), 1996, Integrated Risk Information System, National Center for Environmental Assessment, Cincinnati, Ohio.
(2) Mark Richardson, Environmental Health Directorate, Health Canada, Assessment of Mercury Exposure and Risks from Dental Amalgam, 1995, Final Report, and G. M. Richardson et al, "A Monte Carlo Assessment of Mercury Exposure and Risks from Dental Amalgam", Human and Ecological Risk Assessment, 2(4): 709-761.
(3) World Health Organization (WHO), 1991, Environmental Health Criteria 118, Inorganic Mercury, WHO, Geneva; and W. Craelium, J. Epidemiology and Community Health, 32:155-65,1978.
(4) Agency for Toxic Substances and Disease Registry, U.S. Public Health Service, "Toxicological Profile for Mercury" (ATSDR TP93/10), 1994.
(5) I. Skare, "Mass Balance and Systemic Uptake of Mercury Released from Dental Fillings", Water, Air, and Soil Pollution, 80(1-4): 59-67, 1995.
(6) I. Skare et al, "Human Exposure to Hg and Ag Released from Dental Amalgam Restorations", Archives of Environmental Health 49(5): 384-394, 1994.
(7) J. A. Weiner et al, "The Relationship between Mercury Concentration in Human Organs and Predictor Variables", 138(1-3): 101-115,1993; and "An Estimation of the Uptake of Mercury from Amalgam Fillings", Sci. Total Environment, v168, n3, 1995.
(8) A. Lussi, "Mercury Release from Amalgam into Saliva", Schweiz Monatsschrahnmed, 103(6): 722-6,1993.
(9) M. J. Vimy and F. L. Lorscheider, Faculty of Medicine, Univ. Of Calgary, July 1991. (Study findings) and J.Trace, Elem. Exper. Med., 1990, 3, 111-123.
(10) D. D.Gay et al, 1979, Lancet, May 5, 1985 and C. W. Svare et al, J. Dent. Res., "The Effects of Amalgams on Mercury Levels in Expired Air", 60, 1981, p1668- .
(11) L. Barregard et al, "People with High Mercury Uptake from their own Dental Amalgam Fillings", Occup. Envir. Med., 1995, 52: 124-128.
(12) L. Bjorkman et al, "Mercury in Saliva and Feces after Removal of Amalgam Fillings", Toxicol. Appl. Pharmacol. 1997, 144(1): 156-162.
(13) M. Molin et al, "Kinetics of Mercury in Blood and Urine after Mercury Removal", J. Dent. Research, 1995, 74:420-
(14) D. Zander et al, "Mercury Concentration in Urine in Relation to Number of Amalgam Fillings", 1990, Zbl. Hyg. 190:325-334.
(15) J. Begerow et al, "Long Term Mercury Excretion in Urine after Removal of Amalgam Fillings", Int. Arch. Occup. Health 66: 209-212.
(16) G. Sallsten et al, "Long Term Use of Chewing Gum and Mercury Exposure from Dental Amalgam", J. Dental Research, 1996, 75(1): 594-598.
(17) Dr. I. Gerhard, Dr. E. Roller, et al, Tubingen Univ. Gynecological Clinic, Heidelberg, 1996, BUND Press Release, Jan. 28,1997; and Bundesinstitut fur Arzneimittel un Medizinprodukte, 1997.
(18) B. Windham, Annotated Bibliography of Exposure and Health Effects from Amalgam Fillings, 1997 (over 400 references).
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