ABSTRACT
Pollution of the environment with toxic substances has increased tremendously since the onset of the industrial revolution (Nriagu 1979). Some of these contaminants can interfere with agriculture and also enter the food chain (Dembitsky 2003) by accumulation and biomagni—cation. The threat of heavy metals to human health is aggravated by their long-term persistence (Shaw 1990). Conventional technical decontamination techniques are too costly to remediate extended areas of contaminated soils, and are also environmentally destructive (Bio-wise 2003). These remediation strategies are an ex situ approach and can be damaging to soil structure, ecology and productivity. As an alternative, plant-based bioremediation technologies have received attention as strategies to clean up metal-contaminated soil and water (Raskin et al. 1994; Salt et al. 1995a; Prasad and Freitas 2003; Jadia and Fulekar 2008). All plants have the ability to accumulate from soil and water metals such as Fe, Mn, Zn, Ni, Mo, Mg, and Cu, which are essential for their growth and development. Besides this they can also absorb Cd, Pb, Co, Cr, Ag, Se, Hg which have no biological importance
14.1 Introduction .......................................................................................................................... 293 14.1.1 Phytoextraction .........................................................................................................294 14.1.2 Rhizo—ltration ........................................................................................................... 295 14.1.3 Phytostabilization .....................................................................................................296 14.1.4 Phytodegradation/Phytotransformation ....................................................................296 14.1.5 Phytovolatilization ....................................................................................................297
