Assessing the influence of technosol and biochar amendments combined with Brassica juncea L. on the fractionation of Cu, Ni, Pb and Zn in a polluted mine soil

Abstract

Purpose Soil metal pollution is a widespread problem around the world and remediation of these soils is difficult. The objective of this study was to investigate the effect of two different strategies on the chemical fractions of metals in a soil of a depleted copper mine: (1) amending with a mixture of a technosol made of wastes and biochar and (2) amending combined with planting vegetation (Brassica juncea). Materials and methods A 3-month greenhouse experiment was carried out to evaluate the effects of organic amendments and vegetation on the metal fractionation of Cu, Ni, Pb and Zn in a mine soil of the depleted copper mine at Touro (Spain). We compared the influence of organic amendments alone (technosol + biochar) and combined with mustard plants (Brassica juncea L.). Results and discussionThe results showed that amending with a technosol made of wastes promoted plant growth (from 0.7 to 2.9 g of biomass produced) and reduced the CaCl 2 -extractable metal concentration in soil, reduced the mobility factor of Cu from 18.3 to 1.6, Ni from 47.5 to 2.3 and Pb from 17.9 to 2.1, and also reduced the concentration of metals in the mobile soil fractions. It was not possible to grow up Brassica juncea plants in the untreated settling pond soil due to the extremely degraded conditions of that soil. However, the application of the used technosol increased the Pb and Zn pseudototal concentrations in the amended soils. Conclusions We conclude that the combination of amending with wastes and planting B. juncea provides little additional benefit for remediating a metal-polluted soil compared with incorporation of wastes alone.

Phytostabilization of arsenic and manganese in mine tailings using Pennisetum purpureum cv. Mott supplemented with cow manure and acacia wood-derived biochar

“…The structures of the manure and biochar are suitable for improving soil fertility, as their pores offer increased surface area, nutrition, and moisture retention and can act as beneficial sites for soil microorganisms, while their anionic surfaces can increase the CEC for the retention of positively charged elements ( Mohamed et al., 2017 ; Edenborn et al., 2015 ; Ahmad et al., 2014 ). Furthermore, acacia wood-derived biochar has a high surface area and porosity, which would aid the adsorption of heavy metals ( Rodríguez-Vila et al., 2016 ; Fellet et al., 2014 ). From the SEM-EDS analysis, the biochar surface had a higher composition of carbon and oxygen than that of the manure ( Figure 1 c, d).…”

Pinus halepensis in Contaminated Mining Sites: Study of the Transfer of Metals in the Plant–Soil System Using the BCR Procedure

“…The neutral pH (6.8-7.2) and higher organic carbon content in the CP uppermost soil can decrease the availability of metals (Zn, Pb and Cd) and enhance plant growth to facilitate the phytostabilization process [57][58][59]. Moreover, other studies have also suggested that soil organic amendments can decrease metal availability by the formation of organic metallic complexes [60,61]. According to García-Carmona et al (2019a) and García et al ( 2009), pH appears to be the main property controlling Zn and Cd availability, increasing its solubility in acidic soil conditions [62,63].…”

Towards a Soil Remediation Strategy Using Biochar: Effects on Soil Chemical Properties and Bioavailability of Potentially Toxic Elements

“…Although the authors applied much higher biochar doses than others (20, 40 and 80% wt. ), they found that Zn concentrations in the soil mobile fractions and in the plant Brassica juncea L., were generally higher in the biochar-amended soils compared to the untreated soils, suggesting than Zn was added by biochar itself [193,194]. Chao et al (2018) further elaborated on the phyto-availability of Zn by applying peanut shell biochar (1-5% wt.…”