Assessing simultaneous immobilization of lead and improvement of phosphorus availability through application of phosphorus-rich biochar in a contaminated soil: A pot experiment. (June 2022)

• Record Type: Journal Article
• Authors: Chen, Hanbo; Feng, Ying; Yang, Xing; Yang, Bingshuang; Sarkar, Binoy; Bolan, Nanthi; Meng, Jun; Wu, Fengchang; Wong, Jonathan W.C.; Chen, Wenfu; Wang, Hailong
• Is Part Of: Chemosphere. Volume 296(2022)
• Publication Date: 2022-06
• Subjects: Heavy metal -- Bioavailability -- Soil remediation -- Alternative fertilizer -- Sequential extraction; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2022.133891
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Soil lead (Pb) contamination is often caused by anthropogenic activities. In this study, a pot experiment was conducted to assess the effect of biochars derived from pig-carcass (PCBC) and branches of oriental-plane tree (OPBC) on the bioavailability, redistribution, and phytoavailability of Pb and P, as well as the growth of Ipomoea aquatica Forsk in a Pb-contaminated soil. Application of PCBC increased the total and available P concentrations in the soil as compared to the control, and enhanced the concentrations of labile P and sparingly labile P via direct exogenous P input and improvement of soil pH. Both biochars facilitated P accumulation in plant shoots and roots. Sequential extraction of soil Pb confirmed that biochar application facilitated the transformation of mobile Pb into stable fractions, with greater effects from PCBC than OPBC. Hence, biochar application significantly decreased the soil DTPA-extractable Pb by 90.2% (PCBC) and 64.0% (OPBC) compared to the control, consequently reducing Pb uptake by plants. The Pb immobilization by biochar was driven by the biochar-induced increase of soil pH, Pb-phosphate/carbonate precipitation, ion exchange between Pb 2+ and biochar-derived cations (e.g., Ca 2+ and K + ), and surface complexation with functional groups (e.g., carboxyl, hydroxyl, CO). Application of PCBC simultaneously increased the biomass of plant roots and shoots, by 1.8- and 0.6- folds, respectively. Overall, PCBC showed a potential to function as an effective amendment in the immobilization of Pb and alternative P fertilizer to improve degraded soils. Graphical abstract: Image 1 Highlights: Pig-carcass biochar (PCBC) increased availability and uptake of P in water spinach. Contents of labile and sparingly labile P in soil were enhanced by PCBC addition. Biochar facilitated the transformation of mobile Pb fractions into stable fractions. PCBC was more effective in immobilizing Pb than oriental-planetree branch biochar. Extra P supply and effective Pb fixation by PCBC treatment promoted plant yield.