Kakovost in funkcioniranje onesnaženih vrtnih tal po remediaciji : doktorska disertacija

Jelušič, Maša (author), Leštan, Domen (mentor)

Onesnaženje tal, povzročeno z velikimi količinami antropogenih onesnažil, ki so usidrana v kmetijska in urbana tla, postaja vedno večji svetovni problem in učinkovite metode remediacije so nujno potrebne. V doktorskem delu je bil raziskan vpliv remediacije z ligandom EDTA na vrtna tla iz Mežiške doline, onesnažena s Pb, Zn in Cd, in potencialna uporaba remediiranih tal za gojenje rastlin. Onesnažena tla so bila glede na koncentracijo onesnaženosti oprana z 10, 30, 60 in 120 mmol EDTA kg-1 tal, s čimer se je odstranilo do 80 % Pb, 28 % Zn in 72 % Cd, ter tudi do 75 % mikrohranila Mn. V poljskem poskusu so bila na remediirana in onesnažena tla, položena v dve vrtni gredici (4 Ž 1 Ž 0,3 m), posajene vrtnine. Analiza frakcionacije potencialno strupenih kovin (PSK) na različne talne komponente je pokazala, da so v remediiranih tleh ostale predvsem nedostopne PSK. Biodostopnost PSK v remediiranih tleh za človeka (UBMtest) in rastline (DTPA test) se je z remediacijo bistveno zmanjšala, prav tako pa tudi nevarnost izpiranja (TCLP test). Pridobljene fizikalno-kemijske lastnosti remediiranih tal se v času eksperimenta niso spreminjale. Vrtnine, gojene na remediiranih tleh, so vsebovale manjše, a ponekod še vedno previsoke koncentracije Pb in Cd, ter imele zaradi pomanjkanja mikrohranil, predvsem Mn, in slabših mikrobioloških parametrov (encimski testi), manjšo biomaso v primerjavi z rastlinami, gojenimi na onesnaženih tleh. Za izboljšanje remediiranih tal so jim bili primešani naslednji dodatki: gnoj, hidrogel, vermikulit in stabilizanta Slovakit in apatit ter posejana špinača. Za najobetavnejši dodatek se je izkazal hidrogel, a tudi ta v merjenih parametrih ni dosegel originalnih tal. Alternativa rabe remediiranih tal kot podlage za okrasne rastline in trave (obdodatku mikrohranil in hidrogela) se je izkazala za uspešno. Dobljeni rezultati nakazujejo, da se tudi pri visoki onesnaženosti toksikološki parametri v remediiranih tleh signifikantno znižajo, a tla zaradi porušenega razmerja hranil (Mn) in absorpcije PSK (Cd) v rastline pri veliki onesnaženosti niso primerna za pridelavo vrtnin, medtem ko so se trave in okrasne rastline izkazale za primerno alternativo.

• Language: Slovenian
• Keywords: potencialno strupene kovine, PSK, onesnaženost tal, remediacija, čiščenje tal, pranje tal, ligandi, EDTA, biodostopnost, toksični elementi, težke kovine, Mežiška dolina, disertacije
• Work type: Doctoral dissertation
• Typology: 2.08 - Doctoral Dissertation
• Organization: BF - Biotechnical Faculty
• Publisher: [M. Jelušič]
• Year: 2014
• Number of pages: VIII, 116 f.
• PID: 20.500.12556/RUL-76714
• UDC: 631.4:502/504:543.2(497.4Mežiška dolina)(043.3)
• COBISS.SI-ID: 808567
• Publication date in RUL: 30.12.2015

Secondary language

• Language: English
• Title: Quality and functioning of contaminated garden soil after remediation

Abstract

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.

• Keywords: potentially toxic metals, PSK, soil pollution, remediation, soil washing, ligands, EDTA, bioaccessibility, toxic metals, heavy metals, Meža Valley