Biochar-Assisted Phytostabilization for Potentially Toxic Element Immobilization

Abstract

In response to the growing threat to the quality of the soil environment, new technologies are being developed to protect and remediate contaminated sites. A new approach, namely, assisted phytostabilization, has been used in areas contaminated with high levels of potentially toxic elements (PTEs), using various soil additives. This paper determined the effectiveness of biochar-assisted phytostabilization using Dactylis glomerata L. of soil contaminated with high concentrations of the selected PTEs (in mg/kg soil): Cu (780 ± 144), Cd (25.9 ± 2.5), Pb (13,540 ± 669) and Zn (8433 ± 1376). The content of the selected PTEs in the roots and above-ground parts of the tested grass, and in the soil, was determined by atomic absorption spectrometry (AAS). The addition of biochar to the contaminated soil led to an increase in plant biomass and caused an increase in soil pH values. Concentrations of Cu, Cd, Pb and Zn were higher in the roots than in the above-ground parts of Dactylis glomerata L. The application of biochar significantly reduced the total content of PTEs in the soil after finishing the phytostabilization experiment, as well as reducing the content of bioavailable forms extracted from the soil using CaCl2 solution, which was clearly visible with respect to Cd and Pb. It is concluded that the use of biochar in supporting the processes of assisted phytostabilization of soils contaminated with PTEs is justified.

Examining the Effect of Combined Biochar and Lime Rates on Selected Soil Physicochemical Properties of Acid Soils in Gimbi District, Western Ethiopia

“…In support of the current study, several investigations have demonstrated that the addition of lime and biochar keeps mineral nitrogen in the soil longer by preventing it from leaching [29,31,32]. By contradicting this present study's fndings, Radziemska et al [41] observed higher rates of nitrifcation on severely acidic soil when liming is administered. Te highest soil TMN concentration of Farm-1's control treatment may be because of the soil's relatively inherent N content and higher rate of nitrogen mineralization in soils with low C/N rates.…”

“…However, the Farm-2 soil had recorded the opposite process. It is probable that in this situation, denitrifcation is taking place more slowly than nitrifcation [41,96].…”

“…Various scholars have long argued on the reduction of soil acidity in uses of lime and biochar in the agricultural systems of developed nations [12,30,40,41]. Te benefts of this biochar are not widely recognized in tropical countries, especially in Western Ethiopia.…”

Biochar and Eisenia fetida (Savigny) promote sorghum growth and the immobilization of potentially toxic elements in contaminated soils

“…compost, biochar, zeolites, water treatment residuals, red muds, and lime) (Barbosa and Fernando, 2018;Castaldi et al 2018;Fiorentino et al, 2018;Garau et al, 2022). This kind of approach, which is defined as assisted phytoremediation, was successfully applied in many instances for the remediation of PTE-contaminated soils (e.g., Liu et al 2022;Radziemska et al 2022;Zeremski et al 2021), but very limited and inconsistent information is available for sorghum.…”