Selenium [Se, 34]

Selenium contents of soils and its behavior have received much attention, especially in countries where its deficiency in humans and animals has been recognized. Soils developed on seleniferous parent material (e.g., Cretaceous limestone) and soil contaminated from irrigation water or from coal power plants has also been a real environmental problem. Soils of regions with seleniferous parent materials and Selenium-contaminated soils require alleviation. Soil properties have a great impact on the Selenium phytoavailability. It is easily taken up by plants from akaline sandy soils, in arid climate, than from acidic clay soils, with elevated content of soluble organic matter, in humid climate. Several selenoamino acids, often in association with glutathione peroxidases, were found in both bacteria and higher plants. The pathological changes in animals include growth retardation, skin lesions and hair loss, visual defects, reproductive disorders, pancreas atrophy, liver necrosis, and dystrophy of the skeletal muscle and of the heart muscle.