Biosorption of Lead by Azadirachta indicaAuthor(s): Tyagi S and Tyagi A
Lead is a microelement naturally occurs in trace amounts in all biological materials, i.e. in soil, water, plants and animals. It has no physiological function in the organism According to Cibulka, the main source of lead contamination are smelting works, application of wastewater treatment sludge to soil, transportation, rain, snow, hail and other. Approximately 98% of lead in the atmosphere is from human activities. Neumann et al. have extended the sources of lead pollution by paints, lead wastes, cell batteries, lead solders and forms. Lead is absorbed through plants through roots where most of the lead is also accumulated. In the case of other than root uptake (along roads in urban regions) the content of lead decreases as follows: above ground part > roots > products Intoxication of animals by lead occurs particularly after grazing on pasture contaminated with lead .Lead enters the organism with food and air. In children it affects most the central nervous system. The toxic effects of lead in the prenatal stage cause a shortening of gravidity.