Although iron is essential it is also toxic and the toxic metals include:

• Arsenic
• Lead
• Mercury
• Cadmium
• Iron
• Aluminium

Arsenic - It is the most common cause of acute heavy metal poisoning. It is released from different industries to the environment. Shellfish, cod and haddock contain arsenic. Paints, rat poison, fungicides are the other sources. The target organs are kidneys, central nervous system, digestive tract and skin.

Lead - It accounts for most of the cases of paediatric heavy metal poisoning. It reduces the intelligence of the children. The old houses still have the lead pipes. Industry produces every year 2.5 million tons of lead and most of this is used in batteries. Bones, brain, kidneys and thyroid gland are the target organs. The paints also contain lead salts to dry them quickly. Therefore children should not be allowed to lick painted doors or windows. It is a problem throughout the world. Back hair dye and black printing ink have also lead.

Mercury - Its emissions are there from nature as well as from the industry. Chloralkali plants and paper industries are significant polluters. Dental amalgam is also a source of pollution. Fishes have more mercury. Target organs are the brain and kidneys. The present problem of mercury in our environment is the incandescent light bulbs, which we use in our houses. Some politicians want to ban these bulbs because they consume much more electricity. Politics and industry, therefore, recommend energy saving compact fluorescent light (CFL) bulbs. But, the problem is they keep silent about the mercury present in these energy saving CFL bulbs which then could become one of the serious environmental contamination to our soil and ground water. When these bulbs are used up, they form solid wastes. In Western countries we can give back fused bulbs where we bought them and it is the law which regulates this. What will happen in other countries where there are no such possibilities? People simply throw used up bulbs with their household waste or near their houses, the mercury goes to the soil and ground water. The plants take these metals and the animals along with their feed or grass and we are the last in this chain to get it from our food. We must be very careful to keep ourselves and our families free from such poisons.

Cadmium - it is used in nickel-cadmium batteries, PVC plastics and paint pigments. Cigarette (tobacco) also contains cadmium. The absorption is through respiratory system. Liver, placenta, kidneys, lungs, brain and bones are the target organs.

Iron - it is a heavy metal of concern because iron supplements may acutely poison young children, 5 to 9 years. If the children consume 30mg iron tablets per day, it may spoil their health. The health problems associated with free radicals are dangerous to children. Too much of iron supplement is not healthy for adults. It accumulates in liver, heart muscles, kidney and other organs, rusting a reddish brown oxide coating forms on iron by the action of oxygen and moisture there and producing countless number of free radicals.

Aluminium - it is not a heavy metal but it is ingested through the use of food additives, antacids, nasal sprays and antiperspirants. Other sources are drinking water automobile exhaust, tobacco smoke, aluminium foil, aluminium cookware, ceramics and fancy fire works. Target organs for aluminium are the central nervous system, kidney and digestive system. The question of Aluminium and Alzheimer’s disease is not yet answered. It is proved that aluminium could cross the blood-brain barrier without any problem.