ABSTRACT
Since the beginning of the industrial revolution, heavy metal contamination of the biosphere has increased considerably and became a serious environmental concern. Contamination by heavy metals can be considered as one of the most critical threats to soil and water resources as well as to human health (Yoon et al., 2006). During the past decades, the annual widespread release of heavy metals reached 22000 t (metric ton) for Cd, 939000 t for Cu, 1350000 t for Zn, and 738000 t for Pb (Singh et al., 2003).
