What Are Heavy Metals?

Heavy metals are trace metals with a density at least five times that of water. They are stable elements that cannot be metabolized by the body and get passed up in the food chain to human beings (bio-accumulate). The most common, and harmful, heavy metals are Aluminum, Arsenic, Cadmium, Copper, Lead, Mercury, and Nickel. There are many more existing heavy metals that are not as prevalent or as harmful as the previously noted elements. Heavy metals, in general, have no basic function in the body and can be highly toxic.

Heavy metals are present in the air, drinking water, food and countless human-made chemicals and products. They are taken into the body by inhalation, ingestion, and skin absorption. If heavy metals enter and accumulate in body tissues faster than the body’s detoxification pathways can dispose of them, a gradual buildup of these toxins will occur. High-concentration exposure is not necessary in order to produce a state of toxicity in the body. Most cases of heavy metal poisoning result from chronic low level exposure to these hazardous environmental toxins.

In the last 50 years, human exposure to heavy metals has risen dramatically.  This is the result of an exponential increase in the use of heavy metals in industrial processes and products. Today, chronic exposure comes from toxic waste dump and burn sites, agriculture chemical products, mercury amalgam fillings, lead-based paint, tap water, and chemical residues in processed foods. Personal care products, such as cosmetics, mouthwash, toothpaste, soap, shampoo, and other hair care goods are also sources of contamination. In today’s industry, there is no escaping exposure to toxic metals and chemicals.

In addition to the hazards at home and outdoors, many occupations are subjected to daily heavy metal exposure. Over 50 professions are exposed to mercury on a daily basis. These include physicians, pharmaceutical workers, dentists, dental workers, laboratory workers, hairdressers, painters, photographers, visual artists, and potters.

Studies confirm that toxic heavy metals can directly influence behavior by impairing mental and neurological function. They can also influence the production and utilization of neurotransmitters, and can alter numerous metabolic body processes. Toxic metals can induce impairment and dysfunction in the blood, cardiovascular system, detoxification pathways (colon, liver, kidneys, skin), endocrine (hormonal) system, energy production pathways, enzymatic pathways, gastrointestinal tract, immune system, nervous system (both central and peripheral), reproductive systems, and urinary system pathways.

Breathing heavy metal particles, even at levels well below those considered nontoxic, can have serious health effects. Virtually all aspects of animal and human immune system function are compromised by the inhalation of heavy metal particles. In addition, toxic metals can increase allergic reactions, cause genetic mutation, compete with “good” trace metals for biochemical bonding sites, and act as antibiotics, killing both harmful and beneficial bacteria.

Much of the damage produced by toxic metals stems from the production of oxidative free radicals. A free radical is an energetically unbalanced molecule that “steals” an electron from another molecule in order to restore its balance. Free radicals result naturally when cell molecules react with oxygen (oxidation). With a heavy toxic load, or antioxidant deficiencies, uncontrolled free-radical production occurs. Unchecked free radicals can cause tissue damage throughout the body. In fact, free-radicals can cause tissue damage and underlies all degenerative diseases. Vitamins A, C, and E are some well known antioxidants that curtain free radical activity.

Toxic heavy metals can also increase the acidity of the blood. The blood draws calcium from the bones in order to restore proper blood PH. Toxic metals can set up conditions that lead to inflammation in arteries and tissues, causing more calcium to be drawn to the areas as a buffer. The calcium coats inflamed areas in the blood vessels like a bandage, patching up one problem, but creating another-the hardening and progressive blockage of arteries. Without replenishment of calcium, the constant removal of this important mineral from the bones will result in osteoporosis (the loss of bone density), which leads to an increased risk for fractures of the spine and hips.

*There is considerable scientific debate over this issue in the United States and abroad.


Common Heavy Metals

Sources and Specific Effects

Aluminum, arsenic, cadmium, copper, lead, mercury, and nickel are the most prevalent heavy metals. The specific source of exposure to body tissues, where the metals tend to be deposited, and the adverse health effects of each metal are identified below.

Aluminum

Sources of exposure: Air (high levels of aluminum dust in the workplace), acid rain (dissolves aluminum from soil and rock), plants grown in aluminum laden soil, aluminum cookware, aluminum foil, antacids, antiperspirants, appliances, baking powder (aluminum containing), buffered aspirin, building materials, canned acidic foods, food additives, lipstick, prescription over-the-counter drugs (anti-diarrhea agents, hemorrhoid medications, vaginal douches), processed cheese, “softened” and normal tap water.

Target Tissues: Bones, brain, kidneys, skin, lungs, and stomach.

Signs and Symptoms: Colic, dementia, esophagitis, gastroenteritis, kidney damage, liver dysfunction, loss of appetite, loss of balance, muscle pain, psychosis, shortness of breath, weakness, and fatigue.

Dr. McLaughlin, M.D., F.R.C.P. (C), a professor of physiology and medicine and the director of the Center for Research in Neurodegenerative Diseases at the University of Toronto, states, “Concentrations of aluminum that are toxic to many biochemical processes are found in at least ten human neurological conditions.” Recent studies suggest that aluminum may be involved in the progression of Alzheimer’s and Parkinson’s diseases, Amyotrophic Lateral Sclerosis (ALS), senile and pre-senile dementia, clumsiness of movements, staggering when walking, and an inability to pronounce words properly. Behavioral difficulties among school children have also been correlated with elevated levels of aluminum and other neuro-toxic heavy metals.

Medical Tests for Aluminum Screening: Blood, urine, feces, hair, and fingernails.

Everyone is exposed to low levels of aluminum from food, air, and water. High levels can effect the respiratory and nervous systems and the bones. Aluminum toxicity may also cause birth defects in newborns. Aluminum has been found in at least 489 of the 1,216 (34%) National Priorities List sites identified by the Environmental Protection Agency (EPA).

Arsenic

Sources of Exposure: Air pollution, antibiotics given to commercial livestock, certain marine plants, ores (copper and lead), smelting/refining/processing plants, galvanizing, etching and plating processes, chemical processing, coal-fired power plants, defoliants, drinking water, drying agents for cotton, pesticides, herbicides, insecticides, seafood (fish, mussels, oysters), specialty glass, hazardous waste sites, and wood preservatives.

Target Issues: Most organs of the body, especially the gastrointestinal tract, liver, kidney, spleen, lungs, and skin.

Signs and Symptoms: Abdominal pain, burning of the mouth and throat, garlic-like breath, malaise, fatigue, cancer (especially lung and skin), coma, diarrhea, nausea, neuritis, peripheral vascular problems, dermatitis, skin lesions, and vascular collapse. Low levels of inorganic arsenic decrease the production of red and white blood cells, damage blood vessels, and can cause “pins and needles” sensation in the hands and feet. Long-term exposure can cause darkening of the skin and the appearance of small “corns” or “warts” on the palms, soles, and torso.

Medical Tests for Arsenic Screening: Urine (best), hair, and fingernails.

Exposure to higher than average levels occur primarily in the workplace, near hazardous waste sites, or in areas with naturally high levels. This chemical is present in at least 781 of the 1,300 (60%) NPL sites identified by the EPA.

Cadmium

Sources of Exposure: Air pollution from the burning of fossil fuels (oil and coal) and the incineration of municipal waste materials, art supplies, bone meal, cigarette smoke, food (coffee, fruits, grains, and vegetables) grown in cadmium-laden soil, meats, refined foods, seafood, fungicides, highway dust, incinerators, mining, nickel-cadmium batteries, oxide dust, paints, phosphate fertilizers, power plants, sewage sludge, “softened” water, smelting plants, tobacco, and welding fumes. A prevalent source of cadmium exposure is from tobacco products. Most people who smoke have twice as much cadmium in their bodies than non-smokers. Thirty to fifty percent of what is inhaled is taken up in into the blood stream and retained in the body. Once cadmium enters the body, it is very strongly retained; therefore, even low doses may build up significant cadmium levels in the body if exposure persists for a long period of time.

Target Tissues: Stomach, kidneys, lungs, immune system, liver, testes, nervous system, and the blood.

Signs and Symptoms: Nausea, vomiting, diarrhea, gastrointestinal irritation, pulmonary edema, lung cancer (increased risk), kidney damage, and kidney stones.

Medical Tests for Cadmium Screening: Blood (recent exposure), urine (reflects total presence in body), and hair (less reliable).

Lead

Sources of Exposure: Air pollution, soil, dust, lakes, rivers, ground water (acidic or softened), and drinking water. Mining and manufacturing processes, burning fossil fuels, ammunitions, batteries, metal products like solder and pipes, roofing, old paint, ceramics, and calking are additional sources of exposure. Lead is in the air and attaches to dust. Lead-containing dust is removed from the air by rain. It is prevalent in and around municipal waste incinerators and landfills. Cigarette smoke is also a source of lead; people who either smoke tobacco or are exposed to second-hand smoke, may be exposed to higher levels of lead than people who are not exposed to cigarette smoke.

Target Issues: Lead affects almost every organ system in the body. It is absorbed into the body and distributed to the blood, soft tissue, and bone. The central nervous system is the most vulnerable to lead toxicity, particularly in developing children. Lead also damages the kidneys, liver, gastrointestinal tract, reproductive system, and the immune system.

Signs and Symptoms: Prenatal exposure may cause premature birth and underdeveloped babies. Young children exposed to lead exhibit mental retardation, learning difficulties, and reduced physical growth. In adults, lead may decrease reaction time, cause weakness in the fingers, wrists, and/or ankles, cause hypertension, and possibly effect memory. It can also cause anemia and abortion and it can damage the male reproductive system.

Medical Tests for Lead Screening: Blood, urine, hair.

Mercury

Sources of exposure: Mercury occurs primarily in two forms: organic mercury and inorganic mercury. The inorganic form occurs when mercury is combined with chlorine, sulfur, or oxygen. The organic form occurs when mercury is combined with carbon. The most common form of organic mercury is methyl mercury, which is produced primarily by small organisms in water and soil. Metallic (inorganic) mercury is used in thermometers, dental fillings, batteries, skin-tightening creams, antiseptic creams, and ointments. Other sources include fish, shellfish, and vapors from spills, incinerators, and the burning of mercury containing fuels.

Target Tissues: Nervous system, brain, kidneys, fetus, lungs, and skin.

Signs and Symptoms: Irritability, tremors, changes in vision and/or hearing, and memory problems. Other symptoms include nausea, vomiting, diarrhea, increased blood pressure and/or heart rate, skin rashes, gastrointestinal irritation, eye irritation, renal disorder, and neurobehavioral changes. The EPA has determined that mercuric chloride and methyl mercury are possible human carcinogens. Mercury can pass from mother to fetus and can produce brain damage, mental retardation, incoordination, blindness, seizures, and an inability to speak. Children poisoned by mercury may develop problems with their nervous and digestive systems and kidney damage.

Nickel

Sources of Exposure: Nickel is very abundant and is found in soils, volcanic ash, metal coins, and jewelry. Tobacco smoke, certain foods, and drinking water can also contain various nickel concentrations.

Target Tissues: Skin, respiratory tract, lungs, nasal sinuses, blood, stomach, and kidneys.

Signs and Symptoms: Itchy skin and rashes are the most common symptoms of exposure. It may contribute to asthma, chronic bronchitis, and reduced lung function. Nickel has also been implicated in contributing to spontaneous and threatening abortions. Drinking water with unusually high amounts of nickel may cause stomachaches and damage kidneys. The U.S. Department of Health and Human Services (DHHS) has determined that nickel and nickel containing compounds may be carcinogens. Cancers of the lungs and nasal sinuses have been reported from exposure to dust containing high levels of nickel compounds in nickel refineries and processing plants.

Medical Tests for Nickel Screening: Blood, urine, hair, and feces.


So what can you do about heavy metal toxicity? Check out our Chelation Therapy page!