Mercury Poisoning Diagnosis & Treatment


There are scientific tests used to find out if people show signs of some form of mercury poisoning.

The scientific method for finding out about human exposure to natural (mercury) and synthetic (man-made) chemicals is based on sampling and analysis of a person’s tissues and fluids. Substances studied include blood, urine, breast milk, and expelled air, as well as hair, fat, and bone.

The kidneys generally contain the highest amounts of methylmercury in humans. High levels may lead to kidney damage and failure. Testing urine levels is important in finding out about negative effects on our nervous system; persons affected may show signs of irritation, shaking (tremor), kidney damage, and other symptoms known by scientists to be consistent with mercury poisoning. Exposure to methylmercury is often measured and monitored by testing blood samples. Scientists have found a close link between eating unsafe amounts of contaminated fish and mercury levels in the blood.

The relationship between methylmercury exposure, health effects and hair has been well established. Methylmercury poisoning occurs mostly in food. This compound is absorbed by a person’s blood. Eventually, it becomes a part of a person’s hair and is a good indicator of the consumption of this contaminated food. It is said to be particularly useful in gauging the consumption of contaminated fish by pregnant mothers.

Diagnostic Criteria

In 1976, 1977 and 1979 a panel of experts conducted medical studies at Grassy Narrows First Nation and Wabaseemoong Independent Nation. As a result, these medical experts developed a grading system used even now as grading guidelines to determine whether or not, and to what degree, claimants would qualify for compensation. According to this grading system, or protocol, a 0 score indicates no evidence of mercury intoxication, 3 indicates certain organic mercury intoxication.

Persons of all ages were examined. In 1976, for example, 47.7% were neurologically abnormal, that is there was some brain or nervous system damage. The maximum score was not assigned to any participant in the study in either community. Once various abnormalities were determined, it was found that 16 residents of the Wabaseemoong Independent Nation and 12 residents of the Grassy Narrows First Nation were “assessed as having neurological abnormalities compatible with mercury intoxication.”

As a result of these studies, an adult neuro assessment protocol was established. This ‘guideline’ pointed to 7 different categories of symptoms. For example, tremor, or shaking was one, incoordination was another. A four-level scale was used: none, mild, moderate and severe, to determine how serious the condition was. Number values were also added to help with the grading system; 0-mild to 8, severe.

A separate protocol was established for children. Initially, there were only 2 categories, cerebral palsy and mental retardation. Later they were revised into seven categories. Mild, moderate and severe were adopted as guidelines of severity. The number system for grading adult cases was also adopted. IQ, or intelligence tests, were used in the diagnosis. There was a concern, however, that some of the children would have difficulty understanding the words used in the tests.

Current adult guidelines are the ones recommended for use in 1985.

Treatment for Mercury Poisoning

One method of treatment for mercury poisoning is chelation.

Chelate is a chemical that attracts metal to it instead of being attracted to human tissue, such as the brain and nervous tissue.

Eventually, this mixture of chelate and mercury is sent out of the body as waste, for example, urine. However, some scientists are saying that there is not enough proof that this therapy is truly useful in the reversing of mercury toxins. More research is needed.

Mercury Programs

The term, Mercury Program, is at times used incorrectly.

Some use it to describe the program run by the two First Nations through the Mercury Disability Board. In fact, the Mercury Program was set up in Ottawa in 1975 by the Medical Services Branch of Health Canada. It was designed to monitor levels of methylmercury exposure in targeted First Nations and Inuit communities. The process involves the collection of hair and blood samples from residents of these communities at regularly scheduled times. A person hired by this program coordinates the collection of samples.

The samples are analyzed and stored in Ottawa. It is to be noted that the results are not shared with the Mercury Disability Board. That is, hair and blood sample data, gathered in Wabeseemoong Independent Nations and Grassy Narrows First Nation by the Mercury Program, are not considered in Mercury Disability Board decisions regarding disability claims of residents of these two First Nations.

The Mercury Disability Board is specific only to the Grassy Narrows First Nation and Wabaseemoong Independent Nations.

At the date of publication of Ms. Cosway’s report, this federal program has done 72,556 tests on 40,634 people in the 529 communities involved. The 1978 report shows that 2.54% of the population was at risk. The second group of results showed a large decrease to 0.4% at risk. The third report in 1999 shows a continuing decrease in contamination. It is not clear whether there are fewer contaminated fish, or whether people are eating fewer fish.

Mercury Disability Board

A Historical Report: 1986-2001

The full report (available here) consists of three volumes. It was written by a university student, Sylvia Cosway, who was working on her Ph.D. at the University of Manitoba. The entire study covers over 400 pages in a language more suited to readers with special training in medicine and chemistry. This booklet is written in a simpler style. It avoids many highly technical terms as well most of the details useful primarily to professionals.