Toxic Metals

The Heavy Metals

There are 35 metals that concern us because of occupational or residential exposure; 23 of these are the heavy elements or “heavy metals”: antimony, arsenic, bismuth, cadmium, cerium, chromium, cobalt, copper, gallium, gold, iron, lead, manganese, mercury, nickel, platinum, silver, tellurium, thallium, tin, uranium, vanadium, and zinc.

Small amounts of these elements are common in our environment and diet. Some of these metals, like vanadium and zinc are actually necessary for good health.

Heavy metal toxicity can result in damaged or reduced mental and central nervous function, lower energy levels, and damage to blood composition, lungs, kidneys, liver, and other vital organs.

Long-term exposure may result in slowly progressing physical, muscular, and neurological degenerative processes that mimic Alzheimer’s disease, Parkinson’s disease, muscular dystrophy, and multiple sclerosis. Allergies, including auto-allergic diseases are not uncommon, and repeated long-term contact with some metals (or their compounds) may cause cancer.

For some heavy metals, toxic levels can be just above the background concentrations naturally found in nature. Therefore, it is important to learn about heavy metals and take protective measures against excessive exposure.

In most parts of the United States, heavy metal toxicity is a rarely diagnosed medical condition – maybe due to the lack of doctor’s training. If unrecognized or inappropriately treated, toxicity can result in significant illness and reduced quality of life. For persons who suspect that they or someone in their household might have heavy metal toxicity, testing is suggested.

The association of symptoms indicative of acute toxicity is not difficult to recognise if they are severe, rapid in onset, and associated with a known exposure or ingestion.

Symptoms of acute toxicity include:

Symptoms of chronic exposure

are often difficult to recognize.

They are difficult to associate with their cause.

Symptoms resulting from chronic exposure are very similar to symptoms of other health conditions and often develop slowly over months or even years.

Sometimes symptoms of chronic exposure subside; thinking the symptoms are related to something else, people postpone seeking treatment.

Definition of a Heavy Metal

“Heavy metals” are chemical elements with a specific gravity at least 5 times that of water. The specific gravity of water is 1 at 4°C (39°F). Specific gravity is a measure of density of a given amount of a solid substance when it is compared to an equal amount of water. Some well-known toxic metals with a specific gravity 5 or more times that of water are arsenic (5.7), cadmium (8.65), iron (7.9), lead (11.34), and mercury (13.546) (Lide 1992).

Beneficial Heavy Metals

In small quantities, certain heavy metals are nutritionally essential for a healthy life. Some of these are trace elements (eg, iron, copper, manganese, and zinc). These elements, or some form of them, are commonly found naturally in foodstuffs, fruits and vegetables, and in commercially available multivitamin products (CIS 1999). Diagnostic medical applications include direct injection of gallium during radiological procedures, dosing with chromium in parenteral nutrition mixtures, and the use of lead as a radiation shield around x-ray equipment (Roberts 1999). Heavy metals are also common in industrial applications such as the manufacture of pesticides, batteries, alloys, electroplated metal parts, textile dyes, steel, and so forth (CIS 1999). Many of these products are in our homes and add to quality of life when properly used.

Toxic Heavy Metals

Heavy metals become toxic when they are not metabolized by the body and accumulate in the soft tissues. Heavy metals may enter the human body via food, water, air, or absorption through the skin in agriculture, manufacturing, pharmaceutical, industrial, or residential settings. Industrial exposure is common in adults. Ingestion is the most common route in children (Roberts 1999). Children may develop toxic levels from normal hand-to-mouth activity (ie, coming in contact with contaminated soil or eating objects that are not food such as dirt or paint chips) (Dupler 2001). Less common routes of exposure include a radiological procedure, inappropriate dosing or monitoring during intravenous (parenteral) nutrition, a broken thermometer (Smith 1997), or a suicide or homicide attempt (Lupton 1985).

As a rule, acute poisoning is more likely to result from inhalation or contact with dust, fumes or vapors, or materials in the workplace. However, lesser levels of contamination may occur in residential settings, particularly in older homes with lead paint or old plumbing (CIS 1999). The Agency for Toxic Substances and Disease Registry (ATSDR) in Atlanta, Georgia (a part of the U.S. Department of Health and Human Services) was established by congressional mandate to perform specific functions concerning adverse human health effects and diminished quality of life associated with exposure to hazardous substances. The ATSDR is responsible for assessment of waste sites and providing health information concerning hazardous substances, response to emergency release situations, and education and training concerning hazardous substances (ATSDR Mission Statement 2001). In cooperation with the U.S. Environmental Protection Agency, the ATSDR has compiled a Priority List for 2001 called the “Top 20 Hazardous Substances.” The heavy metals arsenic (1), lead (2), mercury (3), and cadmium (7) appear on this list.