Phytostabilization of a metal contaminated sandy soil. I: Influence of compost and/or inorganic metal immobilizing soil amendments on phytotoxicity and plant availability of metals
ABSTRACT In a lysimeter set-up, compost addition to an industrial contaminated soil slightly reduced phytotoxicity to bean seedlings. The "Phytotoxicity Index" (on a scale from 1 to 4) decreased from 3.5 to 2.8. The same treatment also reduced metal accumulation in grasses: mean Zn, Cd and Pb concentrations decreased respectively from 623 to 135, from 6.2 to 1.3 and from 10.7 to <6 mg kg-1 dry weight. When combined with inorganic metal immobilizing amendments, compost had a beneficial effect on plant responses additional to the inorganic amendments alone. Best results were obtained when using compost (C)+cyclonic ashes (CA)+steel shots (SS). The "Phytotoxicity Index" decreased to 1.7, highest diversity of spontaneously colonizing plants occurred, and metal accumulation in grasses reduced to values for uncontaminated soils. Based on the first year evaluation, C+CA+SS showed to be an efficient treatment for amendment assisted phytostabilization of the contaminated Overpelt soil.
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- "dismutase. Vangronsveld and Clijsters (1992), Mench et al. (1994), Vangronsveld et al. (1995a, b, 1996), and Ruttens et al. (2006) reported that, after incorporating soil amendments like compost, cyclonic ashes, and steel shots, the plant-availability of metals decreased and that this resulted in reductions of activities of stress enzymes in roots and leaves of bean seedlings. With increasing biochar application rates an increasing trend of soluble protein content was observed, but differences between the treatments were not significant. "
ABSTRACT: The potential use of biochar from olive mill waste for in situ remediation of metal contaminated soils was evaluated. Biochar was mixed with metal contaminated soil originating from the vicinity of an old zinc smelter. Soil–biochar mixtures were equilibrated for 30 and 90 days. At these time points, Ca(NO3)2 exchangeable metals were determined, and effects of the biochar amendment on soil toxicity were investigated using plants, bacteria, and earthworms. Bean (Phaseolus vulgaris) growth, metal content, antioxidative enzymes activities, and soluble protein contents were determined. Furthermore, effects on soil microbial communities (activity, diversity, richness) were examined using Biolog ECOplates. After 120 days of soil–biochar equilibration, effects on weight and reproduction of Eisenia foetida were evaluated. With increasing biochar application rate and equilibration period, Ca(NO3)2 exchangeable metals decreased, and growth of bean plants improved; leaf metal contents reduced, the activities of antioxidative stress enzymes decreased, and soluble protein contents increased. Soil microbial activity, richness, and diversity were augmented. Earthworm mortality lowered, and their growth and reproduction showed increasing trends.Environmental Science and Pollution Research 08/2014; 22(2):1444-1456. DOI:10.1007/s11356-014-3467-6 · 2.76 Impact Factor
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- "At a 25 cm depth in all untreated soils, Zn concentrations (Figure 4) were highest during the first and third months. Similar results were reported by Ruttens et al. (2006). In the sludged columns, Zn release to the soil solution was very low compared to untreated columns. "
ABSTRACT: The role of sewage sludge as an immobilising agent in the phytostabilization of metal-contaminated soil was evaluated using five grass species viz., Dactylis glomerata L., Festuca arundinacea Schreb., F. rubra L., Lolium perenne L., L. westerwoldicum L. The function of metal immobilization was investigated by monitoring pH, Eh and Cd, Pb, and Zn levels in column experiment over a period of 5-months. Grasses grown on sewage sludge-amendments produced high biomass in comparison to controls. A significant reduction in metal uptake by plants was also observed as a result of sewage sludge application, which was attributed to decreased bioavailability through soil stabilisation. We have observed that the sludge amendment decreased metal bioavailability and concentrations in soil at a depth of 25 cm, in contrast to untreated columns, where metal concentrations in the soil solution were very high.International Journal of Phytoremediation 06/2014; 16(6):593-608. DOI:10.1080/15226514.2013.798625 · 1.47 Impact Factor
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- "As well as restoring natural cycling of organic matter and nutrients, re-vegetation of contaminated soils is key to onward remediation. The presence of a vegetative cover over bare soil reduces the potential for migration of contaminants to proximal watercourses or inhalation following soil erosion and windblow (Tordoff et al., 2000; Arienzo et al., 2004; Ruttens et al., 2006) but a major limitation to re-vegetation is phyto-toxic concentrations of heavy metals in soils (Pulford and Watson, 2003). Organic soil amendments, such as composts, manures and sludges are now established amongst in-situ alternatives to expensive and/or disruptive hard-engineered removal or capping of contaminated substrates to reduce contaminantassociated risk (Brown et al., 2003; Hartley et al., 2009). "
ABSTRACT: Amending contaminated soils with organic wastes can influence trace element mobility and toxicity. Soluble concentrations of metals and arsenic were measured in pore water and aqueous soil extracts following the amendment of a heavily contaminated mine soil with compost and biochar (10% v:v) in a pot experiment. Speciation modelling and toxicity assays (Vibrio fischeri luminescence inhibition and Lolium perenne germination) were performed to discriminate mechanisms controlling metal mobility and assess toxicity risk thereafter. Biochar reduced free metal concentrations furthest but dissolved organic carbon primarily controlled metal mobility after compost amendment. Individually, both amendments induced considerable solubilisation of arsenic to pore water (>2500 μg l−1) related to pH and soluble phosphate but combining amendments most effectively reduced toxicity due to simultaneous reductions in extractable metals and increases in soluble nutrients (P). Thus the measure–monitor-model approach taken determined that combining the amendments was most effective at mitigating attendant toxicity risk.Environmental Pollution 03/2014; 186:195–202. DOI:10.1016/j.envpol.2013.11.026 · 3.90 Impact Factor