Böcker av Gaur Nidhi S

The environment in which we claim to "live" in has become a hugereservoir of toxic metals. Human health is under constant risk of deterioration dueto increasing chronic exposure of such metals that adversely affect the quality oflife of people. The expedition to meet man's basic need for food, clothing andshelter has continually heightened pollution of the biosphere. The deterioration ofhuman health due to exposure to heavy metals has become a major issue ofconcern worldwide. Although adverse health effects caused by heavy metals havebeen known for a long time, exposure to heavy metals continues, and is evenincreasing in some parts of the world, particularly in less developed countries,even though emissions have declined in most developed countries over the last100 years.The term "heavy metals" refers to any metallic element that has arelatively high density and is toxic or poisonous even at low concentration [1]."Heavy metals" is a general collective term, which applies to the group of metalsand metalloids with atomic density greater than 4 g/cm3, or 5 times or more,greater than water [2]. Heavy metals include lead (Pb), cadmium (Cd), zinc (Zn),mercury (Hg), arsenic (As), silver (Ag) chromium (Cr), copper (Cu) iron (Fe), andthe platinum group elements [3]. Heavy metal toxicity is the excess ofconcentration of toxic heavy metals which have become concentrated as a resultof human caused activities, enter in plant, animal and human tissues viainhalation, diet and manual handling, and can bind to, and interfere with thefunctioning of vital cellular components.