Study of Toxic Effects of Heavy Metals in Soil and Water

Environmental contamination by heavy metal s is a serious problem throughout the world. Heavy metals are toxic which threaten food chain. They accumulates in soil and water due to usage of Industrial effluents ,fertilizers , Pesticides ,Municipal sewage ,vehicles .Heavy metals are elements having a density greater than 5 in their elemental form and comprise some 38 elements .However the term usually and here as well refers to 12 metals that are Cd ,Cr ,Co, Cu, Fe, Hg, Mn, Mo, Ni, Pb , Sn , and Zn. Heavy metals mostly find specific adsorption sites in the soil where they are retained very strongly either on the inorganic ,organic colloids some heavy metals are essential in trace amounts. The International Agency for Research on cancer has classified cadmium as a human carcinogen .The vegetable foods contribute more than 75 % of cadmium intake in humans. The biochemical pathway of heavy metal in the body may be carried out in two major phases. Such as kinetic phase and dynamic phase. Heavy metals are carcinogenic for human health