Mercury Toxicity and Its Many Faces

The Rise of Mercury Awareness

When describing mercury toxicity, one well-known phrase creates a vision of one of its many faces.

“Mad as a hatter. “

You might think the phrase was coined by Lewis Carroll in his 1865 release of Alice in Wonderland, but actually “mad as a hatter” originated because of mercury toxicity and felt hats, like the top hat.

Beaver fur with its serrated edges, easily mats into felt fabric, but hatters treated less expensive furs, like rabbit, with mercury nitrate to roughen them and make the fur fibers more easily mat into felt. Later in the process, hats were steamed, vaporizing the mercury, a process that released it into the air and consequently into the hatter’s lungs.

Accumulations of the heavy metal caused kidney and brain damage. Hatters displayed both physical and mental symptoms of mercury toxicity including tremors (hatter’s shakes), loss of coordination, slurred speech, irritability, loss of memory, and depression. This condition was called “the mad hatter syndrome”.

Although hatters no longer use mercury, mad hatter syndrome is still a common description of the symptoms of mercury toxicity and mercury is still widely used today in the manufacture of many common products.

  • Thermometers
  • Barometers
  • Fluorescent Lamps
  • Batteries
  • Electrical Apparatus (Mercury Switches)
  • Pesticides
  • Paint
  • Pharmaceuticals
  • Cosmetics
  • Dental Amalgams (fillings)

Mercury Toxicity in Your Mouth

The 2003 annual report of the American Association of Poison Control Centers’ Toxic Exposure Surveillance System documented 3362 different types of exposures to mercury.

The two most widely publicized types of Mercury toxicity resulted from fish consumption and dental amalgams.

Fish Consumption

In May 2001, one of Canada’s largest newspapers, the National Post, featured an exposé on the pros and cons of eating fish titled, ”One fish, two fish, good fish, bad fish” in its “Health and Medicine” section.
Eating contaminated fish is the most common route of human exposure to methylmercury, one of the most dangerous forms of mercury. National health advisories in both the US and Canada warn against eating too much tuna, swordfish, mackerel and tilefish.

Washington State has been a leader in combating mercury exposures and the resulting toxicities, issuing fish advisories for specific species in five distinct water bodies. In addition, as of January 1, 2006, it is illegal to sell or distribute many mercury-containing products in Washington, some of which include thermometers, blood-pressure gauges, toys, games, and jewelry.

Dental Amalgams

On December 23, 1990, CBS-TV’s “60 Minutes” delivered a report on dental amalgam called “Poison in Your Mouth”. The report, narrated by Morley Safer, alerted the public to the dangers of mercury in dental amalgams.

Dental amalgams continue to remain a controversial source of mercury toxicity. Currently, Sweden, Denmark and Germany severely restrict the use of mercury amalgams.

On May 8, 2003, Dr. Boyd E. Haley, Professor and Chairman of the Department of Chemistry at the University of Kentucky delivered a lengthy report to the US Congress. His report begins with the statement, “Mercury is the most toxic, non-radioactive element known to man. Virtually every industry has either reduced or banned the use of mercury with the exception of dentistry.”

The report goes on to say, “In fact, in the healthcare industry, mercury has been all but banned” and continues, “The position of organized dentistry, primarily the American Dental Association (ADA), that ‘no valid scientific evidence exists that dental amalgam poses any health risk-other than rare, localized allergic reactions’ is, in my opinion, indefensible in the light of huge amounts of published science.”

Haley also cited a link between autism and mercury toxicity that is supported by the work of English scientist, Dr. Baron Cohen.

Despite this well-documented report and profuse scientific evidence to the contrary, the ADA remains steadfast in its absurd denial about the toxicity of mercury-containing amalgams.

Unfortunately, mercury toxicity doesn’t confine its toxic effect to adults.

One of the determining factors of the severity of mercury toxicity is age. Fetuses, infants, and children are especially sensitive to mercury toxicity, believed to be one of the primary causes of motor and learning disabilities. Other factors include:

  • amount or dose of exposure
  • duration of exposure
  • route (i.e., inhalation, ingestion, skin contact)
  • general health of the exposed person
  • form of mercury involved in exposure

Different Forms of Mercury Vary in Toxicity

Although the public doesn’t encounter all forms of mercury, three forms of the heavy metal threaten us with potential health risks.

Elemental (metallic) Mercury – Natural processes, such as volcanic activity, vaporize and release the pure form of mercury into the air. Although it’s uncommon to stand at the mouth of a volcano, elemental mercury vapors also may be released during breakage of devices that contain mercury, industrial spills, incineration, and dental amalgams.

Organic Mercury Compounds – Both some freshwater and some saltwater fish, marine mammals, some fungicides and pharmaceutical preservatives are sources of organic mercury. Organic mercury poisoning is usually caused by ingesting foods and products that contain organic mercury and is the most prevalent cause of mercury toxicity in the fetus, passed to the child from foods and products ingested by the mother.
Inorganic Mercury Compounds (mercuric salts) – An example of mercuric salts is the mercury contained in automotive batteries. Mercury toxicity from inorganic mercury compounds follows the same routes as organic mercury compounds and elemental mercury. However, the largest danger posed by exposure to inorganic mercury is that environmental microorganisms and fish convert inorganic mercury compounds to the more dangerous organic form of mercury, methylmercury.

The bottom line here is that Mercury in any form is extremely toxic.

Chronic and Acute Toxicity

Acute mercury toxicity usually is related to the inhalation of elemental mercury or ingestion of inorganic mercury and is generally the result of exposure to a large, single dose of mercury. Signs of acute toxicity are numbness, weakness in the extremities, spastic paralysis, and impaired vision. Severe cases of acute toxicity may result in blindness, coma, and even death.

Although exposure to organic mercury may lead to acute toxicity, it most often leads chronic toxicity.

Chronic mercury toxicity is the result of mercury poisoning that has built up in organs and tissues over time. Chronic mercury toxicity may be very general and is often difficult to diagnose in that its symptoms frequently mimic those of other more common illnesses (Cerebral Palsy, Parkinson’s disease, Alzheimer’s disease, dementia, depression, et al). According to Dr. Dietrich Klinghardt, a noted scientist in the research of the toxicity of heavy metals, “mercury alone can mimic or cause any illness currently known or at least contribute to it.”

The skin is an effective defense against most forms of mercury. When it is ingested or inhaled, our bodies convert mercury to a form that is eliminated through normal bowel movements. However, because mercury binds to proteins and body tissues, regardless of the form of mercury, only about one-half of mercury absorbed from any single dose is eliminated from the body.

Unlike other types of poisoning, mercury toxicity affects the neurological system more than the digestive system. Long-term neurological effects from chronic mercury exposure are, today, a major concern that affects all people.