Taking a Look at Heavy Metals

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Heavy metals are elements that exhibit metallic properties. It mainly includes the transition metals, basic metals, some metalloids, lanthanides, and actinides. Many different definitions have been proposed—some based on density, some on atomic number or atomic weight, and some on chemical properties or toxicity (Duffus, 2002). Example for some heavy metal are iron (Fe), zinc (Zn), copper (Cu), lead (Pb), mercury (Hg), cadmium (Cd) etc.

Iron is important as a mineral in human body (part of haemoglobin) and also part of many enzymes and proteins. Deficient amount of iron in human body will cause anaemia while excess amount of iron may cause iron poisoning or hemochromatosis. Zinc is a metal which known as essential trace element as very little amount of it is necessary for human health. Zinc is important for cellular metabolism, catalytic activity of enzyme, immune system, synthesis of protein, wound healing, cell division and DNA synthesis (Sandstead, 1994; Solomons, 1998; Prasad, 1995). However, excess amount of zinc may lead to remarkable health problems such as depressed immune system, stomach cramp, vomiting, nausea and anaemia and skin irritation.

Cadmium (II) ions are known of its toxicity in trace amount may result in poor health effect. Cadmium can be found easily in contaminated food or water. Workers of metal refining or smelting factory or cadmium product manufacturing have a high possibility to be exposed to cadmium. Long term exposure of cadmium lead to
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