Heavy Metal Essay

1.1 BACKGROUND OF STUDY
Heavy metal refers to any metallic chemical element that has a high density and is toxic or poisonous at low concentrations (Ojovan & Lee, 2005). According to Ojovan and Lee, heavy metals include mercury (Hg), cadmium (Cd), arsenic (Ar), chromium (Crow), and lead (Pb). Heavy metals are natural components of the Earth’s crusts; they cannot be degraded or destroyed. They can enter human body in various ways including via the appliances of cosmetics on our body. Some heavy metals are essentials for the metabolism of our body. But too high concentration of the metals can lead to poisoning on the body system too. When talked about the danger of heavy metals, we are talking about the bioaccumulation that heavy metals can do to human tissues. Ojovan and Lee (2005) said that lack of care when dealing with heavy metals could demonstrate the seriousness of high level exposure
Bioaccumulation happens when there is an increase in the chemical concentration in an organism. Toxic metals compounds will accumulate in the body any time they are taken up and were stored faster than they are metabolized or excreted. Most known effect of bioaccumulation it to the pregnant women (Al-Saleh et al.,2009). Other

Heavy metals like Pb, Cd, Hg, As, Se and Zn are categorized as first class of hazard. The sources of heavy metals are industrial sources including present and former mining activities, foundries and smelters and diffuse sources such as combustion by products and traffic fumes. Most of the heavy metals are essential to plant and animal growth as trace elements in order to maintain biological functions (Pam & Brian, 2007). This has mad them to be environmentally significant. Heavy metals can be abundance in some soils and environments where they sometimes occur in rocks or are concentrated by natural