ABSTRACT
There are hundreds of sources of heavy metal pollution, including both natural and human ones. In particular, anthropic activities such as mining, metal working industries, combustion of fossil fuels, disposal of ash residues from coal combustion, vehicular traf—c and the use of pesticides and fertilizers in agriculture (Clemens 2006) signi—cantly contribute to heavy metal pollution, which in turn, impacts negatively on both human and environmental health. While some heavy metals are important as micronutrients, the majority of them are toxic for plants and microorganisms (Schützendübel and Polle 2002).
