ABSTRACT

The chemical and plastic industries are among the major development activities which act as sources of heavy metals in the environment. This chapter discusses cadmium, lead, and selenium in some detail, and explains few important issues of relevance to human and environment health. The range of variation in Ethiopian soils is very wide, although heavy-textured soils predominate. Most of the soils show strong to moderate acidity. To facilitate the comparison of the relative abundance of the microelements in different countries, the frequency distributions of the analytical data in the three plant/soil content zones are summarized. Cadmium is present in natural resources such as soils, water, and rocks as well as in petroleum and coal products. It is rarely found in a pure state. In the earth’s crust, Cadmium is distributed at an average concentration of 0.1 mg/kg. The effect of Cadmium on plants grown in soil and plants grown hydroponically is similar, though less pronounced in soil-grown plants.