CHAPTER ONE INTRODUCTION 1.1 Background of the Study
Industrial wastewater represents the main source of environmental pollution with heavy metals, e.g. Cu, Pb, Fe, Cd, Mn, etc. Such metal may be discharged into the wastewater from various industries, including metal plating, storage batteries, alloy industries, dying, textile, fertilizers and other chemical industries. The progressive increase of industrial technology result in continuous increase of pollution, so that a great effort has been devoted for minimizing these hazardous pollutants and therefore avoiding their dangerous effects on animals, plants and humans (Al-Omair and El- Sharkawy, 2001)
Heavy metal ions are reported as priority pollutants, due to their mobility in natural water ecosystems and due to their toxicity (Volesky and Holan, 1995). These heavy metals are not biodegradable and their presence in streams and lakes leads to bioaccumulation in living organisms causing health problems in animals, plants, and human beings (Ong et al, 2007)
Lead is a pollutant that is present in drinking water and in air. In air, it is derived from lead emissions from automobiles because it is used as an anti knocking agent in the form of lead tetraethyl in gasoline. In water, lead is released in effluent from lead treatment and recovery industries, especially from lead battery manufacturing units. Lead is toxic to living organisms and if released into the environment can both accumulate and enter the food chain. Lead is known to cause mental retardations, reduces haemoglobin production necessary for oxygen transport and it interferes with normal cellular metabolism (Qaiser et al, 2007). Lead has damaging effects on body nervous system. It reduces 1.Q Level in children. Lead is used as industrial raw materials in the manufacture of storage batteries, pigments, leaded glass, fuel, photographic materials, matches and explosives (Raji and Anirudhan, 1997). For drinking water, the maximum permissible limit of lead is 0.1mg/l (WHO, 1971). The maximum concentration allowed for discharge into inland water is less than 1mg/l (FEPA, 1991).