The application of diffusive gradient technique (DGT) for assessment of changes in Cd, Pb, and Zn mobility in rhizosphere

Diffusive Gradient in Thin Films (DGT) technique was applied to determine Cd, Pb and Zn concentrations in rhizosphere of four different plant species: hyperaccumulator Penny-cress (Thlaspi caerulescens J. et C. Presl), trees with a good accumulation capacity willow (Salix dasyclados Vimm.) and poplar (Populus nigra L.) and crop maize (Zea mays L.). Moreover, the effect of two chelating agents (ethylendiaminetetraacetic acid - EDTA, and S,S-ethylendiaminedisuccinic acid - EDDS) on element mobility in rhizosphere like soil was investigated. DGT was able to register even small changes in heavy metal concentrations in rhizosphere according to individual crop and/or soil treatments. A particularly significant effect of EDTA application to enhance solubility of metals bound to solid phase into the soil solution was observed resulting in increased concentrations of mobile metals in rhizosphere. The suitability of DGT technique for evaluation of heavy metal behavior in the environment was demonstrated with reasonable results