A number of toxic metals are present in the environment. Metals of major toxicological concern are Lead, Mercury and Cadmium. Lead: Lead (Pb) cannot be completely eliminated from our environment. Small concentrations of lead are present everywhere. In soil, lead levels range from 5-25 mg per kg; in ground water from 1-60 μg per litre (little lower in natural surface [...]
Bio-activation may be defined as a process whereby certain chemically stable compounds can be converted to chemically reactive metabolites. For example, Parathion, an organ phosphorus pesticide, is bio-activated in the liver to Paraoxon, which is a more potent inhibitor of cholinesterase (ChE). The reactive metabolites such as Epoxides can form covalent binding to cellular proteins and cause necrosis and cancer [...]
The term bioaccumulation is used to refer to storage of a pollutant at levels higher than found in the environment. Many chemicals including dioxins, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organ metallic forms of metals bio-accumulate in animal fat (Hill, 1997) and are difficult to degrade. Lead and fluoride bio-accumulate in bones. Chemicals bound to proteins and cadmium [...]