Dandelion plants (Taraxacum officinale) were sampled together with soil from three sites of the city of Brno differentially impacted by soil pollution. The sampling site at Opuštěná Street situated in the city centre represents a heavily polluted industrial location, the sampling site at Vídeňská Street constitutes a medium polluted location and a relatively clean location is represented by Šrámkova Street. Of the soil pollutants, cadmium, mercury and lead were studied. Cadmium and lead concentrations were determined in the eluates of resin gels, in leachates, plant digestates and in soil solutions using an electrothermal atomic absorption spectrometer ContrAA 700, while the total mercury content in soil, dried plant samples and resin gels was measured using one purpose atomic absorption spectrometer Advanced Mercury Analyser, AMA 254. CE represents the concentration of a metal that is effectively available from both the soil solution and solid-phase labile pool. The metal effective concentrations CE, measured by diffusive gradients in the thin films technique (DGT), were correlated with the metal uptake by plants. The DGT measurement can be also interpreted in terms of the ratio R, which was obtained experimentally. Fluxes of cadmium, lead and mercury to the DGT unit during a 15-day exposure were determined. High correlation coefficients demonstrated that DGT results could be used as physical surrogates for plant uptake, thus offering the possibility of a simple test procedure for soils. The DGT measurement of effective concentrations (CE) may provide a major step forward in assessing the hazards posed by metals in contaminated soils.

22.1.2017