Effects of co-cropping on bioaccumulation of trace elements in Thlaspi caerulescens and Salix dasyclados

Most phytoremediation technologies are based on the use of selected plant species cropped as in monoculture. Separated (monoculture) and combined (simultaneous) cropping of hyperaccumulator Thlaspi caerulescens and accumulator tree Salix dasyclados were tested in our experiment. We used moderately and highly contaminated soil. Extremely contaminated soil caused progressive mortality of willows planted separately. Combined cropping with T. caerulescens enabled willows to survive. Generally, we determined decreased bioaccumulation of As, Cd, and Pb in both tested species and Zn in willow plants. Combined cropping enhanced bioaccumulation of Zn in T. caerulescens shoots. The remediation efficiency of the individual species in the co-cropping system did not differ from those obtained in separate cropping mode. For As and Pb the negligible effectiveness of phytoextraction was confirmed for both separate and combined cropping of the tested plant species.