Heavy metals remediation of water using plants and lignocellulosic agrowastes

Metals in the environment arise from natural sources or directly or indirectly from human activities such as rapid industrialization, urbanization, and anthropogenic sources, threatening the environment and human health (Nriagu 1979). Mining and metallurgical activities produce wastewaters that can be considered as the major source of heavy metal contamination of natural waters (Schalcsha and Ahumada 1998; Reddad et al. 2002a). In the United States alone, more than 50,000 metal-contaminated sites await remediation, many of them Superfund sites (Ensley 2000). They are potential hazards to aquatic, animal, and human life because of their toxicity and bioaccumulative and nonbiodegradable nature (Zuane 1990). Nonessential metals such as Hg, Cd, Cr, Pb,As, and Sb are toxic in their chemically combined forms as well as the elemental form (Manahan 1993).Acute metal poisoning in humans causes severe dysfunction in the renal, reproductive, and nervous systems, and chronic exposures even at low concentrations in the environment can prove to be harmful to human health (Wyatt et al. 1998). © 2006 Springer.