Immobilization and phytotoxicity reduction of heavy metals in serpentine soil using biochar
Date
2015Author
Herath, I.
Rajakaruna, N.
Kumarathilaka, P.
Navaratne, A.
Vithanage, M.
Metadata
Show full item recordAbstract
Purpose: Serpentine soils derived from ultramafic rocks release
elevated concentrations of toxic heavy metals into the
environment. Hence, crop plants cultivated in or adjacent to
serpentine soil may experience reduced growth due to phytotoxicity
as well as accumulate toxic heavy metals in edible
tissues.We investigated the potential of biochar (BC), a waste
byproduct of bioenergy industry in Sri Lanka, as a soil amendment
to immobilize Ni, Cr, and Mn in serpentine soil and
minimize their phytotoxicity.
Materials and methods: The BC used in this study was a waste
byproduct obtained from a Dendro bioenergy industry in Sri
Lanka. This BC was produced by pyrolyzing Gliricidia
sepium biomass at 900 °C in a closed reactor. A pot experiment
was conducted using tomato plants (Lycopersicon
esculentum L.) by adding 1, 2.5, and 5 % (w/w) BC applications
to evaluate the bioavailability and uptake of metals in
serpentine soil. Sequential extractions were utilized to evaluate
the effects of BC on bioavailable concentrations of Ni, Cr,
and Mn as well as different metal fractionations in BCamended
and BC-unamended soil. Postharvest soil in each
pot was subjected to a microbial analysis to evaluate the total
bacterial and fungal count in BC-amended and BCunamended
serpentine soil.
Results and discussion: Tomato plants grown in 5 % BCamended
soil showed approximately 40-fold higher biomass
than that of BC-unamended soil, whereas highly favorable
microbial growth was observed in the 2.5 % BC-amended
soil. Bioaccumulation of Cr, Ni, and Mn decreased by 93–
97 % in tomato plants grown in 5 % BC-amended soil compared
to the BC-unamended soil. Sequentially extracted
metals in the exchangeable fraction revealed that the
bioavailabile concentrations of Cr, Ni, and Mn decreased by
99, 61, and 42 %, respectively, in the 5 % BC-amended soil.
Conclusions: Results suggested that the addition of BC to
serpentine soil as a soil amendment immobilizes Cr, Ni, and
Mn in serpentine soil and reduces metal-induced toxicities in
tomato plants
URI
http://hdl.handle.net/10394/18789http://dx.doi.org/10.1007/s11368-014-0967-4
http://link.springer.com/article/10.1007/s11368-014-0967-4