Every once and awhile, when I was young, a mercury thermometer would shatter, giving us the opportunity to play with the mercury inside. It had an unusual consistency, a shiny color, and broke into tiny droplets that scattered all over so we had to search for them.

Years later, I still search for mercury. But now, I know how dangerous mercury can be, and how many medical problems it can contribute to.

We are all exposed to mercury, both in vapor form and in organic compounds called methylmercury. Coal-burning electric power plants dump 40 tons of mercury into the atmosphere. This vaporized mercury finds its way into streams and lakes, rivers and oceans. Rainwater in several parts of the U.S. has measurable amounts of mercury; a recent study of rain in Chicago demonstrated 42 times the federal safety standard for mercury.

Bacteria in water and soil convert the mercury to toxic methyl-mercury compounds. These are taken in by both fresh and salt water fish. The risk of eating seafood, which otherwise has many health benefits, is just being recognized. A recent coalition of health and environmental agencies compared mercury levels in commonly-eaten fish to the FDA safety standards. They determined that a four-year-old child cannot eat more than one tuna sandwich per week without risking high mercury levels. A pregnant woman who eats a half-can of tuna each day would also expose her unborn baby to an unsafe dose, the report said. The FDA itself has warned that pregnant women should avoid eating swordfish, shark, king mackerel, and tile fish.

A more sensational source of mercury, though possibly less significant than industrial sources, is the presence of mercury in dental fillings, which can contain as much as 50% liquid metallic mercury. Mercury can vaporize during dental procedures and as the patient chews, brushes, or drinks hot beverages, after which it is inhaled or swallowed, entering the bloodstream. Studies have shown a correlation between the number of amalgam fillings and mercury concentration in the blood and urine.

Recently, an added risk of mercury has come to prominence. Thimerosal is a mercury-containing preservative used in some vaccines since the 1930’s. The amounts of mercury are such that, for decades, many infants had received toxic doses of mercury by age 6 months. In July 1999, the Public Health Service (PHS) agencies, the American Academy of Pediatrics (AAP), and vaccine manufacturers agreed that thimerosal should be reduced or eliminated in vaccines.

Mercury has a long and colorful medical history. Mercury began to be added to fillings around the Civil War. Prior to this, dentists steered clear of mercury, also called “quicksilver”. Those doctors who used mercury to treat illnesses, mostly skin conditions, were called “quacksalvers” (Dutch for quicksilver), shortened to quacks, a term that has come to mean physicians who use unproven, possibly dangerous remedies. In the 18^th and 19^th centuries, mercury was added to many remedies. In fact, George Washington is commonly thought to have died from poisoning from calomel, a commonly prescribed mercury medication used for his chronic dental infections. And Abraham Lincoln was known to take heavy doses of mercury for his “melancholy”, possibly leading to bursts of anger, according to historians.

Once mercury is in the system, it is toxic to many organs. Organic mercury compounds easily get into the brain and the nervous system, where they break down to the inorganic heavy metal mercury. This is very difficult to remove once it’s entered the brain, where it can remain for decades. Neurological toxicity of mercury has been known for centuries. In fact, the phrase “mad as a hatter” came from the psychosis associated with 19^th century English hatters who used mercury to stiffen cloth. Modern studies have associated mercury accumulation with Alzheimer’s dementia. Depression, nervousness, irritability, memory loss, headaches, and tremors also can result from mercury toxicity. Multiple sclerosis has shown an interesting correlation with mercury. Many cases of attention deficit and hyperactivity in children seem to be associated with high levels of mercury, and there are numerous reported cases of children with ADD/ADHD improving when mercury is removed from their systems.

Autism is a particular area of suspicion. A recent Dutch study has questioned the relationship between vaccinations and the enormous increase in autism and autistic spectrum disorders (ASD) that we are experiencing. However, many parents insist that their autistic child’s symptoms began suddenly after a vaccination. Now, with the knowledge that vaccinations have been laced with measurable levels of mercury, a possible cause of this finding has come to light.

Mercury has a particular toxic effect on some enzymes commonly involved in cellular energy production. This can lead to fatigue, joint and muscle pain, and sleep problems. Mercury competes with the essential minerals like magnesium, zinc and selenium. Depletion of these minerals leads to the lack of ability to produce energy in the cells.

In addition to its particular effects on the neurological system and on energy production, mercury is toxic to the cardiovascular system. Mercury can raise blood pressure, raise heart rate, and cause several abnormalities in the electrical system of the heart. More importantly, mercury depletes antioxidants from the artery walls while it damages and hardens the walls. Thus mercury can be an important factor in atherosclerotic cardiovascular disease (ASCVD) leading to strokes and heart attacks.

So what can be done about mercury in our bodies? First, there are proper ways of measuring mercury; routine blood testing is not accurate except in acute poisoning. The proper way to test is to take a dose of a medication (DMSA) that pulls mercury out of cells, and then measure the urine for 6 hours. This is called a challenge or provocation test, and will reveal mercury that is in the cells.

Detoxifying the body from mercury can be a long process. Taking antioxidants like glutathione and lipoic acid, herbs like garlic and cilantro, and essential mineral supplements can help. DMSA (also called Captomer or Succimer) is called a chelating agent, since it binds (chelates) and removes minerals. It is relatively safe, and is usually given 3-4 doses every two weeks. Certainly, removing sources of mercury can be critical, even to the extent of replacing old mercury-containing fillings with non-metal ones.

Finally, many people have other heavy metals in their systems, such as lead, cadmium, arsenic and nickel. In these cases, we sometimes turn to intravenous chelation. In any case, removing heavy metals can be a long process, but increasingly necessary and life-enhancing.