Partners and International Organizations
(English)
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A, B, BG, CY, CZ, DK, FIN, F, D, GR, H, IRL, IL, I, NL, N, PL, P, RO, SK, SI, E, S, CH, GB
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Abstract
(English)
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For agricultural land in which low to medium level contamination threatens soil fertility and long term human health, gentle remediation techniques are required that not only reduce toxicological risks, but also restore soil fertility. In contrast to conventional harsh clean-up technologies, phytoremediation is a gentle in situ technique aiming to preserve soil structure and fertility. Unfortunately, efficient metal uptake by remediation plants often appears to be limited by low availability of the metals for uptake by the accumulator plants, in particular in neutral or alkaline soils. In this project we focused mainly on studying the effect of chelating agents on metal uptake by plants. In nutrient solutions containing phosphate, NTA increased shoot Cu uptake in Helianthus annuus and Cu plus Pb (factor of 14.5) uptake in Nicotiana tabacum. In both experiments however Zn shoot uptake was decreased by the presence of NTA. In nutrient solutions also containing montmorillonite (soil substitute) with Cu, NTA increased Cu uptake and translocation into shoots of up to a factor of 26 from montmorillonite suspensions compared to only a factor of 3 without. NTA could be detected in the leaves of Nicotiana tabacum, supporting the hypotheses that metal-NTA- complexes may be taken up by plants. In nutrient solution without phosphate, it was found that SS-EDDS increases shoot Pb concentrations by a factor of 21 but as for the NTA experiments it did not increase shoot Zn. Contrary to the NTA experiments it did not increase shoot Cu uptake either. EDDS did however reduce the accumulation of the target metals in the roots as for the NTA experiments. EDDS has been detected in the shoots, roots and xylem sap of plants from treatments containing EDDS proving that it is taken up in to the above ground biomass of the plant like NTA. In soil experiments EDDS increase both available and soil solution Cu and Zn. This translated into an increase in Cu (factor 6-8) and Zn (factor 2) shoot uptake in the presence of EDDS. In both the nutrient solution Helianthus annuus experiment with phosphate and the soil experiment, in metal only treatments the presence of dual metals affected shoot uptake. Zn reduced the uptake of Cu compared to the Cu only treatment and in the soil experiment Cu also decreased the Zn shoot uptake.
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