Notes
Soil contamination, caused by the large amounts of man-made pollutants being anchored into agricultural and urban soils every day, is becoming a major problem and efficient soil remediation techniques are urgently needed. The aim of the doctoral dissertation was to examine the effect of EDTA remediation on metal (Pb, Zn, and Cd) contaminated soil from Meža Valley, Slovenia, and toassess the potential use of remediated soil for plant cultivation. Soil washing with 10, 30, 60, and 120 mmol EDTA kg-1 of soil, dependent on the degree of contamination, removed 80%, 28% and 72% of Pb, Zn, and Cd, respectively, but also 75% of the essential micronutrient Mn. In a field experiment, we set up two experimental garden beds (4 Ž1 Ž 0.3 m), one filled with the contaminated and the other with the remediated soil, and planted various vegetables. Analysis of metal association with different soil components (sequential analysis) revealed that after remediation, mainly the non-available share of PTMs remained in the soil. In remediated soil, human (UBM method) and plant (DTPA method) bioaccessibility of Pb, Zn, and Cd were reduced compared to contaminated soil, and the leaching hazard (TCLP method) was also reduced. Obtained physicochemical properties of the remediated soils did not change during the time of the experiment. The vegetables cultivated on remediated soil absorbed lower, but still too high, concentrations of Pb and Cd compared to contaminated soil and had inferior growth and, consequently,yield, presumably due to a lack of micronutrients, especially Mn and depressed soil biological parameters (enzyme activity tests). To mend the impaired properties of the remediated soil several amendments were applied: manure, hydrogel, vermiculite, apatite and Slovakite, of which hydrogel proved to be the most prospective. Results indicate that remediated soil, even when highly contaminated with PTMs, retains reduced toxicological parameters. However, due to the disturbed micronutrient balance and plant absorption of PTMs when contamination is high, the soil is not suitable for vegetable production, whereas ornamental plants and grasses proved to be a successful alternative.