**8. Conclusions**

For the studied area, in the vicinity of metallurgical plant of Targoviste city, the heavy metal concentration in soil for Cu, Sn, Pb and Mn exceeded the alert threshold for agricultural soil. For Zn, Ni and Cr, some of the results showed values that exceeded also the alert threshold for industrial soils.

The metal concentration in soil was according with the position against the pollution source.

The heavy metal concentration was widely different in the seven studied species of perennial grasses, and the bioaccumulation capacity was different according with the species and metal concentration in soil. Even a species accumulate high concentrations of metals, this could be because of the high content of metal in soil, not because the species showed accumulative capacity – BF higher than 1 (Table 8).


**Table 8.** The maximal values of heavy metal concentration and bioaccumulation factor for studied plant species

The thermal treatment of plant biomass was an effective method for metal concentration in the material which will be used in metal recovery.

The leaching method should be improved for the extraction of a higher percentage of metals from ash. A quantity of 0.7 mg of metals deposition was obtained after the run of an electro‐ chemical procedure for metal recovery.

By thermal treatment, leaching and electrolysis, small quantities of heavy metals can be recovered from plants used in phytoremediation of polluted soils. The extraction of these elements has advantage for environmental protection, by decreasing the risk of toxicity of heavy metals in soil.
