1. Introduction

Iron is consider as an essential element; its chemical and biological functions evolved from its oxidation and reduction processes and interactions with oxygen [1]. These are very important biogeochemical in natural aquatic systems [2, 3]. It is one of the most abundant metals in the Earth's crust [4]. However, very low concentrations (<10–<sup>9</sup> mol�dm–<sup>3</sup> ) of dissolved, mostly iron (III) organic complexes are present in natural waters due to the low solubility of its thermodynamically stable 3þ ionic form [5, 6]. Iron is used to treat chlorosis (green disease), which often resulting from deficiency of the iron concentration [7]. However, 80 years ago, we did not have any information about the importance of inorganic iron in synthesis of hemoglobin [8]. Many years ago, the nutritional experts became interested in the role of iron in oxygen transport and hemoglobin formation [9]. Most anemia diseases in industrialized countries result from low

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iron intake and bioavailability. On the other side, they are responsible for only about half of the anemia in developing countries [10]. There are other important causes [11] like infectious and inflammatory diseases (especially malaria), blood loss from parasitic infections, and other nutrient deficiencies (vitamin A, riboflavin, folic acid, and vitamin B12).
