Phytoremediation tests on heavy metals bioaccumulation were performed during 2012-2014 with aquatic species Lemna minor, Pistia stratiotes, Eichhornia crassipes, Vallisneria spiralis, Hydrilla verticillata, Cladophora glomerata on samples of contaminated waters collected from the toxic pond of waste landfill Şomârd-Mediaş, Sibiu County. With the purpose to check the species capacity for heavy metal removal and bioaccumulation, comparative analysis of water samples was performed. Three types of experimental waters for each species have been used: drinking plain water as blank; water collected from the toxic pond of Şomârd waste landfills; water with 1/2 dilution from the toxic pond of Şomârd waste landfills. The study was conducted in micro containers with contaminated water using constructed wetlands. The bioaccumulation of heavy metals (Cd, Cu, Ni, Zn, Pb, Fe, Cr) in the green tissue samples (mg/kg dry matter) have been measured after the phytoremediation process. The statistical analysis was performed, based on the determination of microelements with flame atomic absorption spectrometry (ZEEnit 700 Analytik Jena) method. The results have shown that: L. minor plants P. stratiotes and E. crassipes plants were able to extract and to accumulate Cu, Pb, Ni, Fe, Zn, Cr, Cd in their tissues. V. spiralis and H. verticillata plants were able to extract Cr, Cd. The green algae C. glomerata was able to extract Pb, Zn, Cr, Cd. This study has shown that the presence of aquatic species in the toxic pond water have important effects on wastewater phytoremediation in period of two weeks. In order to implement this biotechnology, the tests results have shown a great positive influence of the phytoremediation of contaminated waters using aquatic species in constructed wetlands.
