“…An early study focus of phytoremediation, uptake of toxic metals, including: Hg (Dolar et al, 1971), As (Lancaster et al, 1971;Reay, 1972), and other metals (Stanley, 1974) helped lay a foundation for later phytoremediation research. Our understanding of metals phytoremediation reactions has progressed from basic uptake studies to quantifying the importance of chemical speciation for bioavailability and the role of genetic engineering for hyperaccumulating species (Reay, 1972;Gupta, 1980;Muramoto and Oki, 1983;Campbell et al, 1985;Jain et al, 1989;Outridge and Noller, 1991;Robinson et al, 1995;Schnoor et al, 1995;Debusk et al, 1996;Ali et al, 1999;de Souza et al, 1999;Khan et al, 2000;Compton et al, 2001;King et al, 2001;Lavid et al, 2001;Vajpayee et al, 2001;Zurayk et al, 2002).…”