"Dental Amalgam Fillings" is
the Number One Source of Mercury in People and
Exposure Exceeds Government Health
Standards for Inorganic mercury(vapor)
Bernard Windham
(Ed.)
Government agencies and medical studies have
found that the largest source of mercury in most people who have several dental
amalgam fillings is from amalgam fillings (ref 2‑20,26,27).
Exposure from fillings amounts to from 50 to 90 percent of exposure, with the
average being about 80 % of total exposure (5‑9,12‑15,19,20,26,27).
The studies found that mercury amalgams are unstable due to mercury's low vapor
pressure and galvanic action(24), leaking mercury
vapor continuously into the lungs and saliva at levels exceeding health
standards. The amount
of mercury released by a gold alloy bridge over amalgam over a 10 year period
was measured to be approx. 101 milligrams(mg) (60% of total) or 30 micrograms(ug) per day(21b), and other studies have found similar
results for amalgam fillings(21a,12,18,etc.).
Mercury exposure of most people with
fillings was found to exceed government health standards and levels found to
cause adverse health effects (see below).
The tolerable daily exposure level for mercury
developed in a report for Health Canada
is .014 micrograms/kilogram body weight(ug/kg) or
approximately 1 ug/day for average adult(2) (.04 ug/day for a
6.5 pound infant or .14 ug/day for a 22 pound infant).
The U.S.
EPA Health Standard for elemental mercury exposure(vapor)
is 0.3 micrograms per cubic meter of air(1). The U.S. ATSDR health standard(MRL)
for mercury vapor is 0.2 ug/ M3 of air, and the MRL
for methyl mercury is 0.3 ug/kg body
weight/day(4). For the average
adult breathing 20 M3 of air per day, this amounts to an exposure of 4 or 6 ug/day for the 2 elemental mercury
standards. For an infant breathing 4 M3 of air per day,
this would be 0.8 to
1.2 ug/day and
for a child breathing 8 M3 per day of air this
would be 1.6 to 2.4 ug/day.
The EPA health guideline for methyl mercury is
0.1 ug/kg body weight per day or 6 ug to 8 ug per day for the
average adult(1). This corresponds to a
level of 1 ug/gram in hair which is the EPA reference
level for mercury hair test. (this amounts to 0.3 ug/day for
a 6.6 pound infant and 1 microgram per day for a 22 pound child)
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(3), with other
medical studies finding up to 500 ug/day in gum
chewers or people who grind their teeth(6,11,16,17,18) or some with large
numbers of fillings. The average amount absorbed was above 10 ug/day (ref. 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(2). In a large German study with 20,000 tested subjects
at a University Medical Clinic, the average exposure from fillings was over 10 ug/day and over 50 % of all those with 6 or more amalgam
fillings had daily exposure exceeding the EPA health guideline(6).
Note that
the amount of mercury excreted in feces, as opposed to absorbed, is much higher than
most of these estimates of mercury absorbed by the body. Daily excretion
through feces amounted to from 30 to 190 ug of
mercury, being more variable than other paths(7). Other studies had similar findings(9,12,17-19)
. Most with several amalgams had daily fecal excretion levels over 50 ug/day. The
reference average level of mercury in feces(dry
weight) for those tested at Doctors Data Lab with amalgam fillings is .26
mg/kg, compared to the reference average level for those without amalgam
fillings of .02 mg/kg(27). (13 times that of the population w/o amalgam). Other labs
found similar results(27). This level of mercury gives a daily excretion
of over 30 micrograms per day. There is also evidence that amalgam is also
the largest source of methyl mercury in most people with amalgam, based on
studies and medical lab tests of those who have amalgam
replaced(26,27,12). Mercury vapor and
inorganic mercury have been documented to be methylated
to methyl mercury by mouth and intestinal bacteria, along with candida albicans and other methyl
donars(28),
so that even people who don’t eat
fish but do have several amalgam fillings
have high levels of methyl mercury in saliva and blood.
Studies have consistently found modern high copper non gamma‑two
amalgams have greater release of mercury vapor than conventional silver
amalgams (21-23,25). Recent studies have concluded
that because of the high mercury release levels of modern amalgams, mercury
poisoning from amalgam fillings is widespread throughout the
population"(17,22,18,6). Due to such widespread high exposures the
average person with several amalgam fillings has approx. 10 times higher
mercury exposure than those without amalgam(1b), and
excretes approx. 30 micrograms into the sewer each day, making dental amalgam
the largest source of mercury in sewers.
The high levels in sewers and sewer sludge result in amalgam being a
significant source of mercury in water bodies and fish, and also a significant
source of air emissions from out gassing sewer sludge and crematoria (1c).
Common levels found in persons with amalgam fillings are over 10 times
the Health Canada TDE, and
more than the EPA health standard for mercury vapor. Thus persons with amalgam fillings have
levels of intraoral mercury vapor and body exposure
levels higher than the level 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%. ).
A World Health Organzation Scientific Panel
concluded that a safe level of mercury exposure below which no adverse effects
occur has never been established (3)
References
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Accompanying
data tables by State and Metropolitan Statistical Area http://www.greenpeace.org/usa/assets/binaries/addendum-to-mercury-report
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