Human beings have been exposed to heavy metal toxins for an immeasurable amount of time. The industrialization of the world has dramatically increased the overall environmental 'load' of heavy metal toxins to the point that our societies are dependent upon them for proper functioning. Industry and commercial processes have actively mined refined manufactured burned and manipulated heavy metal compounds for a number of reasons. Today heavy metals are abundant in our drinking water air and soil due to our increased use of these compounds.

They are present in virtually every area of modern consumerism from construction materials to cosmetics medicines to processed foods fuel sources to agents of destruction appliances to personal care products. It is very difficult for anyone to avoid exposure to any of the many harmful heavy metals that are so prevalent in our environment. While it does not appear that we are going to neutralize the threat of heavy metal toxicity in our communities nor decrease our utilization of the many commercial goods that they help produce we can take steps to understand this threat and put into action policies of prevention and treatment that may help to lessen the negative impact that these agents have on human health.

Heavy metal toxins contribute to a variety of adverse health effects. There exist over 20 different heavy metal toxins that can impact human health and each toxin will produce different  behavioral physiological and cognitive changes in an exposed individual. The degree to which a system organ tissue or cell is affected by a heavy metal toxin depends on the toxin itself and the individual's degree of exposure to the toxin.

Here are presented just 5 of the many hazardous metal toxins that are commonly encountered by humans. Each of these metals affects an individual in such a way that its respective accumulation within the body leads to a decline in the mental cognitive and physical health of the individual. The specific sources of exposure where the metals tend to be deposited and the adverse health effects of each metal are identified below. 

1. Aluminum (CAS# 7429-90-5)
Sources of exposure: Aluminum is a naturally occurring metal that has been utilized by humans for a number of years. It is the third most abundant element in the earth's crust (approximately 8% of the crust is composed of aluminum compounds) and is apparent is small quantities (from 3-2400 ppb) in seawater . Incidences of acid rain on the planet have increased the availability of aluminum to various biological systems. Acid rain is able to dissolve aluminum compounds that are naturally found in soil and rock thus increasing their prevalence in soils and fresh and salt-water sources. Because of this aluminum concentrations can be seen in various fresh and salt-water marine lives and in plants that have been grown in aluminum laden soil. Humans have processed aluminum compounds for years and its use is apparent in many different forms of industry. Because of its many industrial and commercial uses aluminum is consumed and/or handled by many individuals on a daily basis.

 Today aluminum can be found in cookware aluminum foil dental cements dentures leather tanning preparations antacids antiperspirants appliances baking powder buffered aspirin building materials canned acidic foods food additives lipsticks construction materials (the automotive aviation and electrical industries all use aluminum compounds for various uses) prescription and over-the-counter drugs (anti-diarrhea agents hemorrhoid medications vaginal douches) dialysates vaccines processed cheese paints toothpaste fireworks and "softened" and normal tap water 

Target tissues:
Aluminum accumulates in the brain muscles liver lungs bones kidneys skin reproductive organs and stomach . Depending on the source of exposure aluminum can be absorbed through the gastrointestinal (GI) tract or the lungs. Absorption through the GI tract is slow due primarily to pH factors but once absorbed it is distributed to the bones liver testes brain and soft tissues. Following aluminum inhalation deposition occurs primarily within the lungs 

Signs and Symptoms:
Aluminum toxicity can produce a number of clinical signs and symptoms. Common are excessive headaches abnormal heart rhythm depression numbness of the hands and feet and blurred vision . Aluminum toxicity has been shown to produce impairment in choice reaction time long-term memory psychomotor speed and recall in affected individuals as compared to controls.

 Animal studies have shown similar impairment in locomotors activity/response and spatial learning in rats receiving dietary aluminum for a period of 12 weeks. In a study conducted with patients receiving dialysis for renal failure aluminum was believed to be a causal agent in the development of dialysis encephalopathy (or "dialysis dementia") a special form of bone disease known as osteomalacic dialysis osteodystrophy and anemia. In this study individuals had been receiving concentrations of aluminum directly from their dialysate. Similarly long-term hemo-dialysis patients have exhibited a progressive neurological syndrome that includes speech disorders dementia myoclonus and encephalopathy . Evidence suggests that inhaled aluminum may contribute to the development of pulmonary fibrosis and to a lesser degree pulmonary granulomatosis 

Aluminum may be involved in a myriad of neurodegenerative diseases. Dr. McLaughlin MD F.R.C.P. a professor of physiology and medicine and the director of the Centre 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 Disease Parkinson's disease Guam ALS-PD complex "Dialysis dementia" Amyotrophic Lateral Sclerosis (ALS) senile and presenile dementia neurofibrillary tangles clumsiness of movements staggering when walking and an inability to pronounce words. To date however we do not completely understand the role that aluminum plays in the progression of such human degenerative syndromes. 

Chronic aluminum exposure has contributed directly to hepatic failure renal failure and dementia. Other symptoms that have been observed in individuals with high internal concentrations of aluminum are colic convulsions esophagitis gastroenteritis kidney damage liver dysfunction loss of appetite loss of balance muscle pain psychosis shortness of breath weakness and fatigue . Behavioral difficulties among schoolchildren have also been correlated with elevated levels of aluminum and other neuro-toxic heavy metals . And aluminum toxicity may also cause birth defects in new-borns.

Medical tests for aluminum screening: Blood urine feces hair and fingernails.

2. Arsenic (CAS# 7440-38-2) 
Sources of exposure: The use of this toxic element in numerous industrial processes has resulted in its presence in many biological and ecological systems. Ground surface and drinking water are susceptible to arsenic poisoning from the use of arsenic in smelting refining galvanizing and power plants; environmental contaminants like pesticides herbicides insecticides fungicides desiccants wood preservatives and animal feed additives; and human made hazardous waste sites chemical wastes and antibiotics. Arsenic concentrations are apparent in the air as a result of the burning of arsenic containing materials such as wood coal metal alloys and arsenic waste  concentrations can also be found in specialty glass defoliants marine life (primarily fish and shellfish) and riot-control gas . Arsenic is present in at least 781 of the 1300 (60%) NPL sites as identified by the EPA .

Target tissues: Many arsenic compounds are readily absorbed through the GI tract when delivered orally in humans. Absorption within the lungs is dependent upon the size of the arsenic compound and it is believed that much of the inhaled arsenic is later absorbed through the stomach after (respiratory) mucocillary clearance. After the absorption of arsenic compounds the primary areas of distribution are the liver kidneys lung spleen aorta and skin. Arsenic compounds are also readily deposited in the hair and nails .

Signs and Symptoms: Arsenic is a highly toxic element that has been used historically for purposes of suicide and homicide. Its health effects are well known and multiform. Acute exposure to arsenic compounds can cause nausea anorexia vomiting abdominal pain muscle cramps diarrhea and burning of the mouth and throat. Garlic-like breath malaise and fatigue have also been seen in individuals exposed to an acute dose of arsenic while contact dermatitis skin lesions and skin irritation are seen in individuals whom come into direct tactile contact with arsenic compounds . A large acute oral dose has caused tachycardia acute encephalopathy congestive heart failure stupor convulsions paralysis coma and even death . Animal studies have shown similar acute effects when arsenic compounds were delivered orally to Rhesus.

Repeat exposure to arsenic compounds have been shown to lead to the development of peripheral neuropathy encephalopathy cardiovascular distress peripheral vascular disease EEG abnormalities Raynaud's phenomenon gangrene of the lower legs ("Black foot disease") acrocyanosis increased vasopastic reactivity in the fingers kidney and liver damage hypertension myocardial infarction anemia and leukopenia.

Other chronic effects of arsenic intoxication are skin abnormalities (darkening of the skin and the appearance of small "corns" or "warts" on the palms soles and torso) neurotoxic effects chronic respiratory diseases (pharyngitits laryngitis pulmonary insufficiency) neurological disorders dementia cognitive impairment hearing loss and cardiovascular disease.

 A significantly higher percentage of spontaneous abortions have been shown in a population living near a copper smelting plant; lower birth weights of babies born to this same population are seen and an abnormal percentage of male to female births is also apparent suggesting that arsenic affects babies in uterus . Studies have shown close associations between both inhaled and ingested arsenic and cancer rates. Cancers of the skin liver respiratory tract and gastrointestinal tract are well documented in regards to arsenic exposure 

Medical test for arsenic screening: Urine (best) hair and fingernails.

3. Copper (CAS# 7440-50-8)
Sources of exposure: Copper occurs naturally in elemental form and as a component of many different compounds. The most toxic form of copper is thought to be that in the divalent state cupric (Cu2+). Because of its high electrical conductivity copper is used extensively in the manufacturing of electrical equipment and different metallic alloys. Copper is released into the environment primarily through mining sewage treatment plants solid waste disposal welding and electroplating processes electrical wiring materials plumbing supplies (pipes faucets braces and various forms of tubing) and agricultural processes. It is present in the air and water due to natural discharges like volcanic eruptions and windblown dust.

Drinking water sources become contaminated with copper primarily because of its use in many different types of plumbing supplies. It is a common component of fungicides and algaecides and agricultural use of copper for these purposes can result in its presence in soil ground water farm animals (grazing animals like cows horses etc.) and many forms of produce Copper is also present in ceramics jewelry monies (coins) and pyrotechnics. Though copper is an essential trace element required by the body for normal physiological processes increased exposure to copper containing substances can result in copper toxicity and a wide variety of complications. 

Target tissues: Absorption of copper occurs through the lungs gastrointestinal tract and skin . The degree to which copper is absorbed in the gastrointestinal tract largely depends upon its chemical state and the presence of other compounds like zinc. Once absorbed copper is distributed primarily to the liver kidneys spleen heart lungs stomach intestines nails and hair. Individuals with copper toxicity show an abnormally high level of copper in the liver kidneys brain eyes and bones 

Signs and symptoms: Acute toxicity of ingested copper is characterized by abdominal pain diarrhea vomiting tachycardia and a metallic taste in the mouth. Continued ingestion of copper compounds can cause cirrhosis and other debilitating liver conditions. Inhaled copper dust or fumes can produce eye and respiratory tract irritation headaches vertigo drowsiness chills fever aching muscles and discoloration of the skin and hair in humans. Vineyard workers exposed to copper fumes for a long period of time developed pulmonary fibrosis and granulomas of the lungs liver impairment and liver disease (cirrhosis fibrosis and various morphological changes). Similar results were obtained in animals chronically exposed to copper containing dust and fumes. Further animal studies on copper toxicity have shown varying degrees of liver and kidney damage (necrosis of the kidney; sclerosis necrosis and cirrhosis of the liver) decreased total weight brain weight and red blood cell count increased platelet counts and the presence of gastric ulcers. Copper also appears to affect reproduction and development in humans and animals. Offspring of hamsters that received copper sulfate injections while pregnant exhibited increased incidences of hernias encephalopathy abnormal spinal curvature and spine bifida . Sperm motility also appears to be compromised by the presence of copper in human spermatozoa .

Chronic exposure to copper can produce numerous physiological and behavioral disturbances. Copper toxicity has been characterized in patients with Wilson's Disease a genetic disorder that causes an abnormal accumulation of copper in body tissue. Wilson's disease is fatal unless treated in time. Manifestations of Wilson's Disease include brain damage and progressive demylination psychiatric disturbances; depression suicidal tendencies and aggressive behavior; hemolytic anemia cirrhosis of the liver motor dysfunction and corneal opacities. Some patients may also experience poor coordination tremors disturbed gait muscle rigidity and myocardial infarction 

Medical tests for copper screening: Blood urine and hair.

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