Biochar application to a contaminated soil reduces the availability and plant uptake of zinc, lead and cadmium

Author(s)

Puga, A. P. ^[1] ; Abreu, C. A. ^[1] ; Melo, L. C. A. ^[2] ; Beesley, L. ^[3]

Affiliation

^[1] Inst Agron Campinas, BR-13020902 Campinas, SP - Brazil

^[2] Univ Fed Lavras, BR-37200000 Lavras, MG - Brazil

^[3] James Hutton Inst, Aberdeen AB15 8QH - Scotland

• Document type: Journal article
• Source: Journal of Environmental Management; v. 159, p. 86-93, AUG 15 2015.
• Web of Science Citations: 100

Abstract

Heavy metals in soil are naturally occurring but may be enhanced by anthropogenic activities such as mining. Bio-accumulation of heavy metals in the food chain, following their uptake to plants can increase the ecotoxicological risks associated with remediation of contaminated soils using plants. In the current experiment sugar cane straw-derived biochar (BC), produced at 700 degrees C, was applied to a heavy metal contaminated mine soil at 1.5%, 3.0% and 5.0% (w/w). jack bean (Canavalia ensiformis) and Mucuna aterrima were grown in pots containing soil and biochar mixtures, and control pots without biochar. Pore water was sampled from each pot to confirm the effects of biochar on metal solubility, whilst soils were analyzed by DTPA extraction to confirm available metal concentrations. Leaves were sampled for SEM analysis to detect possible morphological and anatomical changes. The application of BC decreased the available concentrations of Cd, Pb and Zn in 56, 50 and 54% respectively, in the mine contaminated soil leading to a consistent reduction in the concentration of Zn in the pore water (1st collect: 99 to 39 mu g 2nd: 97 to 57 mu g L-1 and 3rd: 71 to 12 mu g L-1). The application of BC reduced the uptake of Cd, Pb and Zn by plants with the jack bean translocating high proportions of metals (especially Cd) to shoots. Metals were also taken up by Mucuna aterrima but translocation to shoot was more limited than for jack bean. There were no differences in the internal structures of leaves observed by scanning electron microscopy. This study indicates that biochar application during mine soil remediation reduce plant concentrations of potential toxic metals. (C) 2015 Elsevier Ltd. All rights reserved. (AU)

• FAPESP's process: 12/01799-0 - Effects of biochar in mitigating heavy metals toxicity in multicontaminated soils
• Grantee: Aline Peregrina Puga
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 14/04454-9 - Biochar in the remediation of contaminated soils
• Grantee: Cleide Aparecida de Abreu
• Support Opportunities: Regular Research Grants