The in-situ stabilization of potentially toxic metals (PTMs), using various easily available amendments, is a cost-effective remediation method for contaminated soils. In the present study, we investigated the effectiveness of apatite and a commercial mixture of dolomite, diatomite, smectite basaltic tuff, bentonite, alginite and zeolite (Slovakit) on Pb, Zn, Cu and Cd stabilization by means of decreasing their bioavailability in contaminated soil from an old lead and zinc smelter site in Arnoldstein, Austria. We also investigated the impact of 5% (w/w) apatite and Slovakite applications on soil functionality and quality, as assessed by glucose-induced soil respiration, dehydrogenase, acid and alkaline phosphatase and β-glucosidase activity. Both amendments resulted in increased soil pH and decreased PTM potential bioavailability assessed by diethylenetriamine pentaacetic acid extraction and by sequential extractions in the water-soluble and exchangeable fractions. The efficiency of stabilization was reflected in the soil respiration rate and in enzymatic activity. The β-glucosidase activity assay was the most responsive of them.
COBISS.SI-ID: 6755449
Remediation techniques for soils polluted with toxic metals can be divided into two main groups. Immobilization technologies leave metals in the soil, but minimize their availability, while technologies such as soil washing with chelating agents remove metals from the soil. Metals in soil are not entirely accessible to chelating agents and they are consequently not entirely removed. Residual metals left in the soil after remediation remain present in chemically stable species bound to non-labile soil fractions and are considered non-mobile and non-bioavailable and thus not-toxic (bioavailability stripping remediation concept). However, with the re-introduction of remediated soil into the environment, we expose the soil to various environmental factors. They could eventually promote or initiate the transition of the residual metals back to more labile forms to re-establish the disturbed equilibrium. Such a shift would increase the toxicity of the residual metals and, consequently, decrease the final efficiency of soil remediation. Different extraction techniques are used to assess metals bioavailability and the efficiency of soil remediation. Reduced bioavailability of contaminants for organisms is most often assessed by established chemical extraction tests. However, do the chemical extraction tests really provide (include) reliable information on availability of metals for soil fauna? In the present chapter we will discuss the effect of biotic and abiotic environmental factors on the mobility and availability of metals residual in soil after remediation, and the benefits of in vivo assessment of soil remediation efficiency by terrestrial organisms.
COBISS.SI-ID: 6841465
Pollution of soil with various potentially toxic metals (PTMs) is a global problem which needs to be adequately addressed. In-situ stabilization of PTMs using a range of available amendments is a cost-effective method of remediation of contaminated soils. In the present study we investigated the effectiveness of apatite and of a commercial mixture of dolomite, diatomite, smectite basaltic tuff, bentonite, alginite and zeolite (Slovakite) on Pb, Zn, Cu and Cd stabilization by means of decreasing their bioavailability in contaminated soil from an old lead and zinc smelter site in Arnoldstein, Austria. We further investigated the impact of 5% (w/w) apatite and Slovakite applications on soil functional recovery, as assessed with glucose-induced soil respiration and activities of dehydrogenase, acid and alkaline phosphatase and β-glucosidase. These amendments resulted in increased soil pH and decreased PTM bioavailability. The effectiveness of stabilization was largely reflected in the soil respiration rate, and in dehydrogenase and β-glucosidase activities. These correlated (p(0.05) with the results of diethylenetriamine pentaacetic acid (DTPA) extraction and the water-soluble and exchangeable fractions assessed with the sequential extractions. We therefore propose the DTPA and the sequential extractions as tools for monitoring of PTM stabilization efficiency and its impact on soil functional recovery.
COBISS.SI-ID: 6731641