Along with many other toxic compounds in the environment, a lot of heavy metals, or the metals with a very high density, are present in our immediate environment. These heavy metals may contaminate our water supplies, they are components in the clothes we wear, and they are also found in the paints used on houses and in the machines we use at workplaces and in all modern office environments - in short, these metals are components in many simple things we see around in the modern world.
Metals like lead, the ubiquitous aluminum, poisonous arsenic, and metals like mercury and cadmium are present in large quantities in the domestic environment and these are in general some of the most commonly utilized toxic metals in the world today.
The build up of toxicity in the human body may however be very gradual, and the physical effects of poisoning from the heavy metals tends to be a very slow process and occurs over a long period of continued exposure to the source of the toxic metal.
The physical symptoms which are typically induced by the presence of toxic metals in the body tends to be very vague and can include physical symptoms such as persistent fatigue, the appearance of splitting and blinding headaches, the presence of an upset stomach, disorders such as colics and even anemia in some cases.
The central nervous system is the main part of the human body likely to be extremely affected by the presence of toxic metals in the body, and the first symptoms of many accumulated metals in the body is in generating a very significant effect on the functioning of the central nervous system.
Symptoms generated by a disrupted central nervous system include the appearance of muscular tremors, the development of spells of dizziness, the presence of insomnia, the poor concentration abilities in the person and a sudden lack of muscular coordination in the body.
Mercury for example has been linked to the debilitating disease of multiple sclerosis as a possible causative factor, in much the same way, the toxic effects of accumulated aluminum has also been linked to the appearance of Alzheimer's disease in many cases.
Many developmental problems and disorders in new born babies have been directly linked to early exposure to toxic metals and pregnant women must be especially careful in handling any substances which have a high concentration of known heavy metals, developmental problems in children can have both mental and physical aspects.
Gums lined with a blue tinge or hue are the strongest indicators of a manifestation of lead poisoning in the body of a person, in addition, such individuals will also suffer from acute muscle weakness and different kinds of mental disturbances or disorders.
The accumulation of lead to toxic lead levels in the body will finally induce the paralysis of the tissues marking the extremities of the body, and other symptoms such as blindness, and mental disturbances also tend to affect patients.
Lead poisoning also tends to cause memory loss in all patients, the continued presence of lead in extremely large amounts within the body can lead to eventual mental retardation for the affected individual, lead poisoning can also cause insanity, it can give rise to impotence in men, and cause different types of reproductive disorders in affected individuals.
The milder and much more subtle physical symptoms of lead poisoning are the presence of a metallic taste within the mouth, disorders such as persistent indigestion, the development of complete appetite loss, the presence of disorders such as constipation, and problems like nausea and vomiting are also very easily apparent due to lead poisoning.
The presence of large amounts of the toxic metal arsenic in the body on the other hand, brings about severe vomiting; patients are affected by constant diarrhea and cramping in the abdominal region.
On the other hand the accumulation of high levels of the metal cadmium is known to bring about recurring instances of kidney stones in the patient; this mineral is also known to be capable of replacing the stores of the mineral zinc in the human body.
Liver damages is one typical symptom of the presence of high cadmium, this mineral may be the least known heavy metal among all the others, but it can also cause high blood pressure and damage the liver.
The best scientific way of recognizing the presence of these toxic minerals in the body is through chemical analysis of hair samples - most of these toxic metals end up accumulating in the dead tissues of the hair.
At the same time, post mortem chemical analysis usually check for the presence of heavy metals in vital areas of the patients body - these include samples of the tissues in the brain, the kidneys, and liver and bone samples - all of which tend to have a fair amount of toxic metal accumulation.
The recognition of the toxic effects of heavy metals and the regulation of their use in industrial and domestic processes is a fairly new phenomenon of the modern world-all of these toxic metals have seen widely use through the history of man.
As more of the extreme toxicity of some of these metals has become clear to us, we have made more attempts to curb and restrict their uses to processes which will not directly threaten human life. The Roman civilization is said to have been destroyed because Roman nobles preferred their food cooked only in lead vessel.
As pollution and the entry of pollutants into the natural environment have increased-it is normal to find that contaminated shellfish and organ meats which have much higher heavy metals concentrations.
Shellfish absorb heavy metals from the polluted water they live in, while organs meats of cattle and pigs usually also contains high metals content due to the detoxifying function of the liver, spleen kidneys etc. the presence of high amounts of toxic chemicals has also been detected in drinking water sources.
At the present time, most scientist are still unsure about the physiological effects of drinking polluted water over the long term, with particular reference to polluted water that is soft and very corrosive.
Another very good source for heavy metals is the highly toxic pesticides and insecticides used on farms and domestic houses around the farm-agricultural farms treated using such chemicals also retain some of the heavy metals and can be said to be polluted in some war due to this factor. The high metal content of cigarette smoke is one reason that tobacco is considered so unhealthy.
Among the thousands of chemicals traced in cigarette smoke, the content of toxic metals such as arsenic, lead and cadmium is very prominent - it is the presence of such chemicals which causes damage to the body, the nicotine itself being quite harmless. Many domestically used compounds such as dental filings, gasoline, dyes and insect repellents tend to have high concentrations of many of the heavy metals.
In the United States, very high levels of the toxic metal lead is generally to be found in the chemicals making up older style house paints, the metal is also normally used for water pipes and is found in high amounts in leaded gasoline. High amounts of the metal lead are also to be found in some kinds of foods and nutritional supplements, which include bone meal and the mineral dolomite.
Heavy contamination of the soil with the metal lead is also a fact, the automobile has been massed produced and used for decades now and till recently all vehicles ran on leaded gasoline.
The packing industry also used a lot of lead before, and such cans can easily leach the toxic metal lead due to the leaching effects of many acidic fruits and vegetables, in particular tomatoes, drinks like wine and cider, and colas and many types of juices can quite readily cause the heavy metals to leach from cans meant for storing them.
Though not in use in North America anymore, the metal lead was used as a sealant in seam tin cans, this sealing lead is still to be seen in the tins or cans of certain imported goods from other countries. Ceramic is also another source for the toxic metal lead and usually has good amounts of the metal in the glaze.
The toxicity of the heavy metal mercury is far greater than that of the lead. Mercury content of polluted water is quite high in many places; in addition, this poisonous metal finds its way into the flesh of many fishes and shellfishes which live in such waters.
Another probable source for the contamination of mercury may be the silver-colored amalgam of the metal which is used in dental fillings; these have generated a great deal of attention in recent years as sources of toxic mercury contamination.
It is believed that mercury leaks into chewed food when people who have such filling eat a meal, approximately half of the filling consists of the metal mercury-this is a very direct source of possible mercury toxicity.
Mercury is also found in different agricultural weed killers, it is a constituent of printing ink, it is also used in some paints and the processed latex also has high mercury content. Poisonous metal arsenic is also found in many of the insecticides used at present, high levels of this toxic metal have been detected in some animal feeds and in many ceramic products.
The amount of aluminum in households is the greatest compared to the other metals mentioned here, this is because the real effects of aluminum on the human body over the long term is still an area that needs careful examination-this metal is used in many domestic environments.
Aluminum alloys go into the manufacturing of different types of pots and pans and the metal is ubiquitous in distribution. Aluminum may leach into food when cooking is done with pots or pans made from the metal aluminum or its alloys, this situation may particularly prevail when the food being cooked has great acidity such as the cooking of foods like the tomatoes and other high acid content vegetables and fruits.
In addition, the active ingredient in many marketed antacids and anti-perspirants have a high aluminum content in addition to the universal use of aluminum foil is in processes like baking and other household cooking tasks.
Aluminum is also found in chemical form in many different types of prescription medications, it is widely used in skin creams and in products like vaginal douches. The major industrial regions and areas have high levels of the metal cadmium - which is another extremely toxic metal.
Cadmium has been detected in large amounts in different tobacco products; it has found its way into the drinking water of municipalities and is also a component in many different pesticides. Cadmium contamination of shellfish, and animal organs such as the accumulation in the livers and kidneys of farm animals is a concern.
When such foods are consumed by humans, the metal may slowly accumulate in the kidneys, the lungs, and in the heart and bones over a period of time.
The therapeutic use of the metal arsenic was known to the Greeks and Romans twenty four hundred yeas in the past, they also identified its potential as an effective poison for the human body.
The metal can damage the mitochondria in human cells and this is its main toxic effect, these tiny organelles within each cell of the human body are responsible for the production of energy in the human body - any interference in the action of mitochondria usually results in the death of the cell and if done on a large scale then it can lead to the death of the individual.
The metal arsenic finds many uses in the world today; it is an active component in many insecticides and takes part in the treatment of some of the rarer protozoan infections that can affect the human body.
The toxic metal arsenic released in industrial processes as a by product during the smelting of copper, zinc and lead, the content of this heavy metals is also quite high in coal. Arsenic content has been found to be high in some of the mineral waters.
Compounds which contain arsenic have been used in the poultry industry and in the feeds of other livestock as a growth promoter of the reared animal. The metal has also found use as a preservative agent for wood and wood products.