by Paul J. Dunn, MD, charter member of the American Holistic Medical Association, member of the American College of Advancement in Medicine, the American Academy of Environmental Medicine, and the Academy of Orthomolecular Medicine; and member and past president of the International Academy of Nutrition and Preventive Medicine, with a private practice in complementary and integrated medicine in Oak Park, Illinois

The incidence of mercury toxicity is much more prevalent in the general population than even possibly many physicians realize. It affects many people from the developing fetus to infants, children, and adults of all ages. Reports in the recent past have pointed out the possibility of mercury poisoning from leaking gas meters and other mercury containing devices like thermometers, thermostats, blood pressure manometers, barometers, and elemental mercury collected by hobbyists. The incidence of mercury toxicity is actually greater than would be expected from these sources alone.

"On average, Chicago rainwater had mercury levels 12 times higher than that human standard."

The cycling of mercury in the environment results from both human and natural activities. Since the beginning of the industrial age the amount of mercury released into the atmosphere has markedly increased. Most of this is mercury vapor, which circulates in the atmosphere for up to a year. It can be dispersed widely and be carried for thousands of miles from its point of origin. It is in the inorganic form of mercury salts and in organic forms such as methyl mercury. It is removed from the atmosphere by precipitation and deposited in surface waters and on land. Even after this deposition it is commonly emitted back into the atmosphere either as a gas or a particle form and re-deposited elsewhere. Most of these emissions are from coal fired power plants and from municipal and medical waste incinerators. It ends up in lakes and rivers and is absorbed by fish. The aquatic food web is where mercury accumulates most efficiently. Higher mercury concentrations generally are found in predatory fish at the top of the food web. Most of the mercury in fish tissue is methyl mercury1.

An article on this mercury contamination in the Chicago Tribune of September 14, 1999 revealed data collected by the University of Michigan Air Quality Laboratory. "Sixty-five samples of rainwater falling on the campus of the Illinois Institute of Technology showed mercury levels ranging from 5.4 parts per trillion to 74.5 parts per trillion. The level considered safe by the EPA for wild life in the Great Lakes is 1.3 parts per trillion. For humans the safe level for the Great Lakes was established at 1.8 parts per trillion. On average, Chicago rainwater had mercury levels 12 times higher than that human standard. In all cases the rain itself is not harmful but serves as the primary source of the mercury to the lakes where it accumulates in the creatures living there."2

In Wisconsin, State environmental officials have issued warnings against eating mercury contaminated fish from about 340 lakes and rivers. They believe, however, that those most susceptible to harm, i.e., women of child-bearing age, pregnant women, and young children, are not getting the information. Wisconsin distributes 40,000 copies per year of its annual fish advisory but this does not cover the 1.5 million people who get fishing licenses in the state every year. A 1998 survey of Wisconsin women between ages 18 and 45 conducted by the Bureau of Environmental Health showed that only one fourth of the respondents were aware of the state advisories on mercury.

Amalgam is 50% mercury. With chewing, mercury vapor is released and readily absorbed.

Not everybody who eats fish from Lake Michigan or any other similar body of water is going to get mercury toxicity. Exposure and toxicity are related to the species of fish eaten, the concentrations of methyl mercury in the fish, the quantity of fish consumed, and particularly—how frequently fish is eaten. There are probably more people than we realize who eat a lot more fish than most because it is a free source of protein. This is particularly important for pregnant women because of the potentially devastating effect on the fetus. Methyl mercury and metallic mercury are well known neurotoxic agents. Rapid changes in central nervous system development and functions occur during the early postnatal period and the neonatal brain therefore is very sensitive to damage.3,4 Breast milk is another source of exposure.5,6,7 Transfer of mercury to the developing fetus is even worse.

Besides exposure to mercury from the external environment, there is possibly another very significant exposure from a person’s internal environment, namely, dental amalgam fillings.9,10,11,12 Amalgam is 50% mercury. With chewing, mercury vapor is released and readily absorbed. The degree of mercury toxicity that may result is related to the number of amalgam fillings present, with large fillings on the chewing surfaces being more significant.

Health problems resulting from mercury toxicity can be related to the brain, lungs, kidneys, and possibly other organs and systems. Symptoms could be fatigue, headache, neuromuscular pain and stiffness, poor concentration and memory to name just a few. Various other causal factors can also result in these symptoms but where there is a history of possible mercury exposure from eating fish, from amalgam fillings, or from a mercury spill, then toxicity from exposure to this toxic element should be investigated.

Incidentally, anyone who still has amalgam fillings in their mouth should not use the supplement lipoic acid because it mobilizes mercury into other parts of the body.

Exposure of the fetus and young children can be a significant factor in future learning, developmental and/or behavioral disabilities. It has been estimated that approximately 12 million children under age 18 are affected by one or more of these problems. A study by the National Academy of Sciences found as many as 60,000 children nationwide each year may suffer learning disorders and more serious neurological and nervous system development problems from exposure to mercury.8 Attention deficit hyperactivity disorder (ADHD) and attention deficit disorder (ADD) affect very many US school children. About 1.5 million of these children are taking Ritalin®. Here too other factors are involved in the underlying disorder such as hypoglycemia, food sensitivities, trace mineral imbalance, candida related complex, osteopathic problems, and neurological disorganization. Mercury toxicity and possibly also lead are present in some of these children and must be considered as part of an integrated evaluation.

When I see patients, who present with a variety of chronic symptoms that are not responding to the usual and customary treatment, I first of all do a very comprehensive medical, family, and social history along with a complete general, neurological, and osteopathic examination. Based on this information, I recommend what I think ideally would be good tests to do that would investigate the various causes of the underlying disorder that has been causing their chronic symptoms. This would include a hair and blood mineral analysis for trace minerals and toxic minerals like mercury, lead, arsenic, aluminum, nickel, and cadmium. If I suspect mercury toxicity at that time or later, I also do a mercury challenge test on urine using DMSA (dimercaptosuccinic acid) or DMPS (2,3-dimercapto-1-propanesulfonic acid). These are chelating agents, which combine with the mercury making a more soluble compound that the body then can excrete in the urine and stool. Tests for mercury vapor in the mouth before and after chewing can also be done by some dentists equipped to do this.

Treatment consists of using these agents and other substances such as chlorella, cilantro, selenium, and a series of intravenous vitamin C infusions to bring about detoxification. Since DMPS and DMSA can also chelate with other minerals, these should be replaced with a good trace mineral supplement on days when not taking the oral chelating agent. Removing the source of the mercury is obviously another essential part of treatment. Other metabolic problems, nutritional deficiencies, and osteopathic lesions contributing to the basic underlying disorder also must be part of the integrated multifaceted treatment plan. In the case of amalgam fillings being a culprit they should be replaced with a nontoxic material in such a way as to minimize aggravating the situation through removal. A dentist, who has had some further training in this regard, should do this procedure. Incidentally, anyone who still has amalgam fillings in their mouth should not use the supplement lipoic acid because it mobilizes mercury into other parts of the body. If someone suspects that his/her chronic problems may be related to mercury exposure it is very important to consult a health care practitioner to have this evaluated and treated. Mercury toxicity is very much related to one’s own health and to that of any future offspring.

In my own practice I have had several patients who had no amalgam fillings in their mouth but their hair mineral analyses showed high levels of mercury. Subsequent DMSA challenge tests for mercury excreted in the urine also showed high levels. In each instance, fish had been frequently consumed over a long period. The treatment plan is bringing about clinical improvements and also decreasing mercury levels.

I have heard some reports of reactions to using DMSA for the challenges test and for treatment. In my experience I have not seen these problems either for the test or for treatment using appropriate dosage every other day 3 times a week. This protocol has also been effective in lowering levels of mercury slowly.

In my own practice I have had several patients who had no amalgam fillings in their mouth but their hair mineral analyses showed high levels of mercury. . . . In each instance, fish had been frequently consumed over a long period.

The nutritional benefits of eating fish are well known. Reading this article should not lead to eliminating fish from the diet. Eating a moderate amount of fish no more than twice a week as a part of a good nutritional program and an otherwise healthy lifestyle probably would be no problem. The FDA (Food and Drug Administration) recommends that women of childbearing age eat shark or swordfish (which accumulate mercury from their prey) no more than once a month. Everyone else should limit those fish to seven ounces a week. The FDA also recommends that everyone limit grouper, marlin, and orange roughy to 14 ounces a week13. If one eats tuna it should be white albacore tuna because it is from smaller fish and has less mercury. The amount of even this tuna should be limited. The EPA (Environmental Protection Agency) says that the people at greatest risk are recreational fishers who eat large amounts of locally caught fish from mercury polluted waters.13

Following these guidelines for reducing our mercury toxicity and other contributing factors will help us attain at least close to optimal health.


1EPA Office of Air and Radiation, "Mercury Study Report to Congress: Overview," September 26, 2000.
2Kendall, Peter, "Rain Adds to Lakes’ Pollution, Report Says," Chicago Tribune, September 14, 1999.
3International Programme on Chemical Safety (IPCS), "Methylmercury (Environmental Health Criteria 101)," Geneva, Switzerland: World Health Organization, 1990.
4International Programme on Chemical Safety (IPCS). "Methylmercury (Environmental Health Criteria (118)," Geneva, Switzerland: World Health Organization, 1991.
5Skerfving S., "Mercury in women exposed to methylmercury through fish consumption and in their newborn babies and breast milk," Bulletin on Environmental Contamination and Toxicology, 41:475-82, 1988.
6Grandjean P., P. J. Jorgensen, and R. Weihe, "Human milk as a source of methylmercury exposure in infants," Environmental Health Perspectives, 102:74-7, 1994.
7 Amin-Zaki L., S. Elhassani, M. A. Majeed, et al, "Studies of infants postnatally exposed to methylmercury," Journal of Pediatrics, 41: 475-82, 1988.
8Monahan, John J., "Rain Polluted with Mercury: Level of Toxin Triggers Concern," Telegram and Gazette - Worcester, September 20, 2000.
9Langworth S., C. G. Elinder, and A. Akesson, "Mercury exposure from dental fillings. I. Mercury concentrations in blood and urine," Swedish Dentistry Journal, 12:69-70, 1988.
10Akesson J., A. Schultz, R. Attewell, et al, "Status of mercury and selenium in dental personnel: impact of amalgam work and own fillings," Archives of Environmental Health, 46:102-9, 1991.
11Barregard L, G. Sallsten, and B. Jarvholm, "People with high mercury intake from their own dental amalgam fillings," Occupational and Environmental Medicine, 52:124-8, 1995.
12Lorscheider, F. L., M. J. Vimy, and A. O. Summers, "Mercury exposure from silver tooth fillings; emerging evidence questions a traditional dental paradigm," Faseb Journal, 9:504-8, 1995.
13 Anonymous, "Mercury rising," Nutrition Action Health Letter, 25:4, June 1, 1998

Article from NOHA NEWS, Vol. XXVI, No. 2, Spring 2001, pages 3-4.