The metals which have high atomic weight are called heavy metals. Examples: mercury, zinc, cadmium etc.
The long-lasting effect of heavy metals creates a great injury in the body of human beings and other animals. Every day we come in contact with many metals and chemical reagents. Antimony, Arsenic, Bismuth, Cadmium, Cerium, Chromium, Cobalt, Copper, Gold, Platinum, Mercury, Nickel, Silver, thalium, Tin, uranium vanadium etc are the heavy metals.
Heavy metals have a great dangerous pressure on the environment which create disturbance the fundamental activities of plants. Again these heavy metals arc more poisonous for the living organism.