摘要: There is considerable information published concerning the environmental effects of some toxic metals, for example, cadmium, mercury and lead, where their potency has been demonstrated to cause problems. However, there a growing need extend our knowledge encompass other elements in Periodic Table which may exhibit an unrecognized toxicity living organisms. Any element that biochemically active be potentially hazardous crops, livestock, wildlife man himself. Many factors determine risk potential particular element, whether it bioaccumulative, mobile, persistent or continually released into environment. For these reasons necessary provide basic about nature so adverse can anticipated before they occur.