Carbohydrates, lipids and proteins are the main source of energy that required in the human body. Elements such as Sodium, Potassium, Calcium, Magnesium, Manganese, Zinc, and Lead are also needed by the body in small amounts to help balance the physiological and structural functions. These elements are found as a salts of organic acids or complexes with proteins and lipids [1].
In general, elements can be classified into three main categories, essential trace elements which include elements that vital processes need it to happen in the body. They are required in the body in relatively large amounts (several grams), such as iron, manganese and zinc…etc. Semi-essential trace elements: the absence of these elements has a small effect on the body, such as fluorine, nickel, bromine....etc. Non-essential trace elements, include elements with no biochemical importance for the body but it is presence can disrupt important chemical reactions causing poisoning as a result of it is accumulation, such as mercury, gold, silver and aluminum [2]. The amount of elements was increasing above normal limits in the plants that consider as a main source for human food as a result of increasing the amounts of pollutants in the soil and water by the sewage waste and fertilizer residues, causing imbalance of the eco-system [3] due to accumulation of difficult bio-degradable elements in the soil [4]. As a result of its importance, Tuzen and Soylak [5] have estimated some elements in a group of vegetables (tomatoes, some green vegetables) in Turkish markets using flame and non-flame atomic absorption in gravity furnace after a process of digestion. Then it was compared to studies done in several other countries. Sharma [6] was estimated some heavy elements in some of the vegetables produced and marketed during December, February, October and November in one Indian city in 2009. Also some of the essential elements were estimated [7] in some vegetables grown and consumed in Ghana using neutronic analysis and found increasing in concentration of some metals such as Mg, Ca, Na, K, Co, Mn, and Br in the studied vegetables. Tomatoes, eggs, onions and carrots have the highest concentration levels of these elements.