Content area
Full Text
ABSTRACT
Virtually, an unlimited number of different mixtures of pollutants occur in the environment, and the number and concentration of chemicals in these mixtures are highly variable. In trace amounts, some heavy metals are essential for optimum health, while exposure to others, which are non-essential, present the potential hazard of acute or chronic organ toxicity. Metal pollutants can be classified as either essential elements (important for life) or nonessential elements (with no known physiological functions to humans).Metals generally regarded as essential for human health in trace amounts include iron, zinc, copper, manganese, chromium, molybdenum and selenium. They are essential because they form an integral part of one or more enzymes involved in a metabolic or biochemical process. The primary role of such elements is as a catalyst, and only trace amounts are necessary for cellular function. These metals are widely found in nature, particularly in various mineral deposits and soils, meaning that they are available to be taken up by plants and animals that serve as food sources for humans. Another metals like, calcium and sodium are essential for human health but which are not viewed by nutritionists as metals. A characteristic associated with essential metals is that the body provides homeostatic mechanisms that increase or decrease uptake and excretion as needed to maintain the necessary levels in the body. Adequate amounts are particularly important during pregnancy, and for infants and children during periods of rapid growth. Non-essential metals (NEMs) are priority pollutants that pose potential risks to human health and the environment. Exposure to NEMs such as arsenic, cadmium, lead and mercury has been associated with a significant number of adverse health effects in humans.
(ProQuest: ... denotes formulae omitted.)
INTRODUCTION
Recently, researches have proved that, the constituents of human corps are the same as earth especially minerals and metals [1].
Metals play important roles in a wide variety of biological processes of living systems. Homeostasis of metal ions, maintained through tightly regulated mechanisms of uptake, storage and secretion is therefore critical for life and is maintained within strict limits [2, 3]. Metal ion transporters participate in maintaining the required levels of the various metal ions in the cellular compartments [4].
It is also known that several essential transitional metals, such as zinc,...