The changes of risk element mobility and plant-availability in contaminated soil treated with dry olive residue

Bc. Tereza Stejskalová

Master's thesis

Abstract:

Abstract The importance of the olive oil agroindustrial activity in Mediterranean area is well known. The two phase extraction system is the most widely used technology to obtain oil and generates a semi-solid organic waste called alpeorujo, olive mill dry residue (DOR). This residue due to its organic matter and mineral nutrient content might be used as a promising material for in situ remediation of the soil as a risk element stabilization agent and furthermore as fertilizer (Nogales et al. 1999). Unfortunately, like the majority of plant byproducts, DOR can be phytotoxic. Approximately 4 or 5 million tons of alpeorujo per year are produced in Spain and uncontrolled disposal of the DOR might lead to serious environmental issue in the main olive growing regions. DOR cannot be directly applied to the soil but close relationship was found in saprophytic fungal transformation of DOR which can effectively stabilize the organic matter content, enhance C/N ratio and substantially reduce the phenolic fraction content in the waste (Sampedro et al., 2009).In this experiment, the combined treatment of biotransformed DOR and arbuscular mycorrhizal fungi (AMF) was observed as suitable management option for the stabilization of the risk elements in extremely contaminated soil. Also, the impact on changing the nutrient status and bioavailability of risk elements in soil treated with biotransformed DOR by four species of fungi: Penicillium chrysogenum, Funalia floccosa, Bjerkhandera adusta, Chondrostereum purpureum and AM fungus Funneliformis mosseae was investigated as well as the effect of this treatment on the risk element uptake by wheat plant (Triticum aestivum L.) cultivated in a pot experiment with the Cd, Pb, and Zn contaminated soil. The results showed substantial role of both biotransformation of DOR and AM inoculation in the plant growth and element uptake by wheat plants. Moreover, the mobile proportions of elements on the treated soils were related to increasing soil pH, where significantly decreasing Cd, Cu, Fe, Mn, P, Pb, and Zn mobility (r values between -0.36 and -0.46), and increasing Ca and Mg mobile proportions (r = 0.63, and r = 0.51, respectively) were determined. The biotransformed DOR application lowered the mobility of risk elements (Cd, Zn), and nutrients (Ca, Cu, Fe, Mg, Mn) in the aboveground biomass, where the elements retained in higher extent in roots. Thus, the biotransformed DOR application to the risk element contaminated soil can reduce the risk element accumulation in aboveground biomass of plants, although the reduction was insufficient for safe crop production in the extremely contaminated soil.

Keywords

biotransformed dry olive residue, risk elements, wheat, pot experiment, stabilization, immobilization

Language used: English

Date on which the thesis was submitted / produced: 12. 4. 2017

Thesis defence

• Supervisor: prof. Ing. Jiřina Száková, CSc.

Czech University of Life Sciences Prague

Faculty of Agrobiology, Food and Natural Resources

Master programme / field:
Natural Resources and Environment / Natural Resources and Environment