Iron [Fe, 26]

Iron plays a special role in the behavior of several trace elements and is in the intermediate position between macro and micronutrients in plants, animals, and humans. Iron is considered to be the most mobile metal among others deposited in bed sediments. Iron concentration in the wetland sediments from the effluent at the Savannah River site is 18,421 mg/kg, and its highest amounts, 8,089 mg/kg, is fixed in soluble OM fraction. Iron is considered to be the key metal in the energy transformation needed for several live processes of plant cells. Iron deficiency may occur at very different levels in plants, and is dependent on various factors, such as soils, plants, and climates. Iron-containing oxygen storage protein in the muscles, myoglobin, is similar in structure to hemoglobin, but has only one heme unit and one globin chain. Iron-containing enzymes, cytochromes, also have one heme group and one globin protein chain.