The effectiveness of various treatments in changing the nutrient status and bioavailability of risk elements in multi-element contaminated soil

Abstract

Potential changes in the mobility and bioavailability of risk and essential macro- and micro-elements achieved by adding various ameliorative materials were evaluated in a model pot experiment. Spring wheat (Triticum aestivum L.) was cultivated under controlled condition for 60 days in two soils, uncontaminated Chernozem and multi-element contaminated Fluvisol containing 4900 ± 200 mg/kg Zn, 35.4 ± 3.6 mg/kg Cd, and 3035 ± 26 mg/kg Pb. The treatments were all contained the same amount of sulfur and were as follows: (i) digestate from the anaerobic fermentation of biowaste, (ii) fly ash from wood chip combustion, and (iii) ammonium sulfate. Macro- and micro-nutrients Ca, Mg, K, Fe, Mn, Cu, P, and S, and risk elements Cd, Cr, Pb, and Zn were assayed in soil extracts with 0.11 mol/l solution of CH3COOH and in roots, shoots, and grain of wheat after 30 and 60 days of cultivation. Both digestate and fly ash increased levels of macro- and micro-nutrients as well as risk elements (especially Cd and Zn; the mobility of Pb decreased after 30 days of cultivation). The changes in element mobility in ammonium sulfate-treated soils appear to be due to both changes in soil pH level and inter-element interactions. Ammonium sulfate tended to be the most effective measure for increasing nutrient uptake by plants in Chernozem but with opposite pattern in Fluvisol. Changes in plant yield and element uptake in treated plants may have been associated with the higher proline content of wheat shoots cultivated in both soils compared to control. None of the treatments decreased uptake of risk elements by wheat plants in the extremely contaminated Fluvisol, and their accumulation in wheat grains significantly exceeded maximum permissible levels; these treatments cannot be used to enable cereal and other crop production in such soils. However, the combination of increased plant growth alongside unchanged element content in plant biomass in pots treated with digestate and fly ash suggests that these treatments have a beneficial impact on yield and may be effective treatments in crops grown for phytoremediation.

Organic and inorganic amendment application on mercury-polluted soils: effects on soil chemical and biochemical properties

“…Similar mechanism was identified to be responsible for increasing the soil pH after soil amendment applications (Janoš et al 2010;Garcia-Sánchez et al 2015a). However, Chernozem and Luvisol samples amended with digestate showed higher pH values in comparison with those samples amended with fly ash in both Chernozem and Luvisol soil after 21 days of incubation.…”

“…On the basis of a previous study conducted in our laboratory, we expected amendment application would influence changes in soil pH more than would time of incubation (Garcia-Sánchez et al 2015a). The pH is an important soil parameter which regulates the metal availability and toxicity.…”

Implications of mycoremediated dry olive residue application and arbuscular mycorrhizal fungi inoculation on the microbial community composition and functionality in a metal-polluted soil

“…The incorporation of organic amendments to metal-polluted soils has been suggested as a suitable option for enhancing the soil pH, OM content, and the microbial structure and functionality with subsequent metal bioavailability reduction (García-Sánchez et al, 2015a, b). Among the different organic amendments, such as, anaerobic digestion residues (digestate) and/or composts, used in recovering of metal degraded-soil (Alvarenga et al, 2008;Epelde et al, 2014;García-Sánchez et al, 2015a;Zornoza et al, 2015), the application of mycoremediated dry olive residue (MDOR) has resulted in a profitable strategy in decreasing the bioavailability of metals (Hovorka et al, 2016). The MDOR, which consists of the biological transformation of dry olive residue (DOR) through different species of saprophytic fungi with potential abilities to convert/transform the DOR into a suitable soil amendment (mycoremediation), has been reported as an environmentally sound management option for its use as an organic amendment, as previously observed by Sampedro et al (2004).…”

Optimization of Bioslurry-Available Plant Nutrients Using T. brownii and Acanthaceae spp. Biocatalysts

“…(15.767 ± 1.243 g/L) (α � 0.05, n � 14). Biogas slurry ammonium levels are known to increase linearly over time [50]. It is worth noting that the Acanthaceae spp.…”