Mercury Toxicity: Disease & Exposure

By Cat, August, 2007; moved and updated from iWeb 4/24/22

It was not generally known until the late-1950s/early-1960s that mercury was a very toxic substance. And its been only in the last 20 years that we’ve known how to detox from it. As a child in the ’50s, I was exposed to mercury from the following:

    1. silver amalgam tooth fillings;
    2. using mercurochrome to heal cuts (until it was banned);
    3. playing with mercury “marbles,” and
    4. certain lab experiments in graduate school that involved inhaling mercury.

Mercury Toxicity 

For an excellent video on the damage mercury can do to your brain and nerve tissue, watch a University of Calgary video (13) (also available on Dr. Mercola’s site (1d)).

For more detail on how mercury affects your health, refer to Affects of Mercury Toxicity. < need link to Cat’sKitchen version

Mercury may well be the most problematic of the toxic heavy metals, because it is a ubiquitous environmental pollutant.  Mercury poses a unique problem because it is routinely used in medical and dental practices.  Silver fillings are made with mercury; vaccines are preserved with thimerosol, a compound of mercury.   In 2008, the FDA reversed it’s stance and now admits the mercury in dental amalgams is harmful; see FDA (14), (1e), or (15).  The ADA and USDA have yet to fall in step. 

Mercury is highly problematic because of its affinity for sulphur, effectively disabling the sulfur-containing molecule from doing its proper function.  Sulfur is present in many enzymes, antibodies, glutathione (antioxidant), neurotransmitters and other brain chemicals, and hemoglobin (the protein that carries oxygen through the blood).  Sulfur is also present in lipoic acid, a critical cofactor in cellular energy production. (2) 

Mercury has the ability to hide in the body, and can be quite hard to remove from its hiding place.  It has quite a long tissue half-life, ranging from days to decades, depending on the affected organ. 

Disorders & Health Problems Associated with Mercury

Mercury toxicity has been implicated in the following disorders/health problems (2); see also Advanced Health Plan chart (16):

  • anorexia;
  • asthma;
  • autism;
  • behavioral problems (ADHD, agitation, sleep difficulties, self injurious behavior);
  • cognitive impairment (retardation, poor concentration, memory problems, visual problems); 
  • fibromyalgia;
  • gut problems (abdominal pain, diarrhea, colitis, increased gut permeability);
  • motor disorders; 
  • psychiatric disturbances including depression and anxiety; 
  • sensory abnormalities (mild to sever hearing loss, touch aversion, light sensitivity);
  • skin problems (rashes, eczema, dermatitis, itching);
  • speech and language difficulties.


Mercury exposure can happen through: 

  • inhaling into our lungs, such as from dental amalgam fillings;
  • ingesting it in food (such as contaminated fish); and
  • by absorption from vaccines that include thimerasol (includes mercury) as a preservative. 2022: I note that the CDC (17) and FDA (18) tout thimerasol is safe in vaccines, but I don’t trust them.

But by far, the most prevalent mercury exposure is through the lungs.   Mercury, and mercury compounds, are commonly used in (5): 

  • chemical labs;
  • hospitals;
  • dental clinics;
  • factories that make fluorescent light bulbs, batteries, explosives;
  • Coal plants for energy generation;
  • treatment of leather and furs; 
  • exterior and marine paints.

Food exposure: There is quite a controversy about fish consumption.  Organic mercury is present in certain fish, as it concentrates up the food chain.  Thus fish that eat smaller fish are more likely to contain measurable mercury than fish who eat algae and plankton.  Also, fish from ‘clean’ waters are less likely to be contaminated than those from waters near sources of industrial pollution.  See “Organic Mercury” below, for a list of common fish to be avoided: (9)

Forms of Mercury 

Elemental: Elemental (quicksilver) mercury is not readily absorbed from the digestive tract; therefore, exposure from a mercury thermometer is not appreciably toxic. (9)  Elemental mercury readily vaporizes at room temperature, forming a colorless gas that can be inhaled or, to a lesser extent, absorbed through the skin.   Because elemental mercury is readily absorbed through the lungs, inhaled mercury (such as from dental amalgams) is a real problem. (5) 

Inorganic Mercury: Exposure to inorganic mercury (salts of mercury, such as mercurous chloride) usually results from ingestion, for example of mercury containing batteries, or contaminated food.    Mercury salts have also been used in topical medical preparations as anti-microbial agents and for skin whitening. (10)   

Organic Mercury: While inhaled mercury involves elemental mercury,  the most toxic form is organic mercury–mercury bound to hydrocarbons, for example: methyl mercury.  Like inorganic mercury, exposure to organic mercury usually results from ingestion of contaminated food.  

The most often cited culprit is fish, especially those high on the food chain, as mercury accumulates upward in the food chain.  But this is not without controversy, as some experts believe the benefit of Omega-3 fats from certain fish outweighs the harm from mercury, especially for women who are pregnant or nursing.  For more on this controversy, see Mercola (1b). Also check out the (19) for a neat calculator on mercury exposure from fish.

The Canadian government suggests limiting consumption of suspect fish to once per week or less (once per month for children and women of childbearing age).  They cite the following fish as “suspect”: (9) 

  • fresh and frozen tuna *
  • marlin
  • shark
  • swordfish
  • tilefish
  • king mackerel
  • oysters (Gulf of Mexico source)

and freshwater species: (9) 

  • bass
  • pike
  • muskellunge
  • walleye

 *NOTE:  Canned tuna is not considered problematic because it involves smaller, short-lived fish that have not had much chance to concentrate mercury.  Thus, the recommended maximum for canned tuna is one 7 oz can per week, for adults.(9) 

Other sources of organic mercury are: (9) 

  • antiseptics
  • fungicides
  • industrial run-off
  • vaccines containing thimerosol as a preservative

Forms of Toxic Mercury Exposure

Inhaled Mercury: Check out a YouTube video (20) to learn more about Inhaled Mercury and how it negatively affects your health.

After eating a nice meal, you brush your teeth, smile at yourself in the mirror, and go on about your day, never suspecting that you have just added to your woes.  That is, if you have silver filings in your mouth.

Those silver fillings contain a high percentage of elemental mercury, a highly toxic substance.  Your dentist and the ADA have assured you that those fillings are safe, harmless. That there is no way the mercury, a solid silvery metal, could get into your system from your teeth.  But your dentist is wrong. (The ADA is protecting its members from massive law suits…)

Dentists and dental assistants are themselves impacted, perhaps to an even greater extent than the general population, because of their constant exposure to mercury.  Studies on people in the dental profession have shown higher incidence of subclinical motor and neuro-psychological deficits than control subjects. (4)

Research in 1985 demonstrated that elemental mercury (Hg) is continually released from dental amalgams immediately after chewing or brushing of teeth.  Mercury is highly volatile, meaning that it converts from its common solid form to vapor form quite readily, and you breathe it into your lungs from your mouth. In the lungs the mercury is picked up by the blood and carried to distant cells, where it is quickly taken into the interior of the cells.   Further studies using monkeys in 1989 demonstrate with whole-body imaging that mercury from dental fillings concentrate in the kidney, intestinal tract, brain, liver, and other organs including bones. (4) 

Once in the cells, it is converted by a cellular enzyme to a ionic form (Hg2+) that does not readily exit the cell.  Instead, it stays in the cell and does its toxic damage.  It can stay in the cell for decades.

So what? you ask.

Its a BIG DEAL.  Mercury is very toxic to the metabolic processes of our cells.  And is especially toxic to the liver and to the central nervous system function.  Do you remember the Mad Hatter in Alice and Wonderland?  He was ‘mad’ (crazy) because of exposure to mercury in the tanned hides he used to make his hats.

The mainstream medical and dental professions do not believe mercury from amalgam fillings is a problem.  To ‘prove’ their point, they cite blood and urine sample analysis of people with amalgam fillings, which do not show toxic levels of mercury. (9)  However, this is no proof at all, because once inhaled, mercury is very quickly taken up from the blood by cells, and converted to a form that does not readily exit the cell.  Thus not much is free to be excreted in the urine.

2022 note: many medical/dental professionals are beginning to take notice of the harm amalgam fillings are doing; including problems in the brain…

Research has shown that the mercury vapor from dental fillings accumulates in the pituitary gland, hypothalamuus, thyroid gland, adrenal gland, and occipital cortex, in direct proportion to the number and extent of amalgam surfaces (fillings). (8)  

Organic Mercury

While inhaled mercury involves elemental mercury,  the most toxic form is organic mercury–mercury bound to hydrocarbons, for example: methyl mercury.  Exposure to organic mercury usually results from ingestion of contaminated food, such as fish.  

Once ingested, organic mercury is very rapidly absorbed, because it is fat soluble.  Once absorbed, organic mercury associated with longer hydrocarbon chains is usually broken down into inorganic form.  However, shorter-chain organic mercury, such as methyl or ethyl mercury, is stable in its original form, and is highly toxic; more so than inorganic mercury. (9) 

These stable forms of organic mercury then distribute uniformly throughout the body, and accumulate in the brain, kidney, liver, hair, and skin.  They readily cross the blood-brain barrier, and also the placenta, to infect the fetus, where they can cause teratogenic effects. (9) 

Cat’s note: Stable forms of organic mercury likely play a role in dementia. 

Methyl mercury penetrates red blood cells, and concentrate there. It has a half life in the blood of about 44 days. For acute toxicity, a blood test will reveal the presence of methyl mercury in the blood cells.(9) 

Like inorganic mercury, methyl mercury has a high affinity for sulfhydryl groups (SH), and has similar dysfunctional effect on enzyme function. (See Affects of Mercury Toxicity article for more). The enzyme chiefly targeted by methyl mercury is pyruvate dehydrogenase, which is involved in energy production within the cells. This enzyme complex contains a molecule of lipoic acid, which contains a SH group.  Once lipoic acid is bound by mercury, the entire complex is irreversibly inhibited from its action. (5a)  

The most common symptom of methyl mercury toxicity is extreme fatigue.  Fish from contaminated waters is the most common source.  Recent testing of sushi bars show that sushi does often appear to be contaminated with mercury, and in some cases worse so than other fish. (1c)

Diethyl mercury is the most toxic organic mercury compound. And it readily penetrates not only the skin, but also latex, PVC, butyl and neoprene gloves.  A small amount (less than a drop) of dimethyl mercury can cause death.  One researcher died from dimethyl mercury poisoning within 5 months of exposure.  It is believed that dimethyl mercury, which can readily cross the blood-brain barrier, binds to a SH group in the amino acid cysteine.  Cysteine is very important to brain health. (5a) 

Ethyl mercury is a related compound that is one of the breakdown products of thimerosol, a preservative used in many vaccines.  Its action is similar, but not identical to that of methyl mercury. (5a)

Inorganic Mercury

Inorganic mercury (salts of mercury, such as mercurous chloride) does most of its damage to the gastrointestinal tract, and to the kidneys, where it can cause severe kidney damage.  There are two ionic (salt) forms of mercury: 

  • Mercuric (Hg+1) and
  • Mercurous (Hg+2). 

Mercurous salts are usually more toxic than mercuric salts because they are more soluble in water and are more readily absorbed from the digestive tract.

I remember my Father, who suffered from what he thought was psoriasis on his legs, treated it with a product called Mazon Medicated Cream, which contained mercury salts (the product is still available, but reformulated to remove the mercury).  The Mazon eventually caused burns on his skin.  It is also interesting to note that Dad’s official cause of death (other than old age–he was 81), was kidney failure.  Inorganic mercury does most of its damage to the kidneys.

Sadly (for me), as a child, I loved the smell of the Mason cream and often removed the lid to sniff it; and now I too am having kidney issues.


  1. Mercola: (note his articles may have been removed from his site)
    2. (was 11); link is no longer valid
    3. (was 12)
    5.—-FDA-Forced-to-Admit-That-Mercury-Fillings-are-Hazardous-63715.aspx – no longer valid (4/24/22)
  2. (original link no longer valid); do a search for “alpha lipoic acid mercury” for other sources
  4. 2022 WARNING: this site might by risky:
  5. Wikipedia:
  9. MedScape: 
  11. link moved to 1b 
  12. link moved to 1c
  14. FDA: (link is no longer valid 4/24/22)
  15. no longer valid as of 7/2010
  16. -chart
  20. video:

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