Journal of Applied Biosciences (J. Appl. Biosci.) [ISSN 1997 - 5902]
Volume 10(1): 491 - 499. Published October 2008.
Phytotoxicity and remediation of heavy metals by fibrous
root grass (sorghum)
Chhotu D. Jadia and M. H. Fulekar*
*Environmental Biotechnology Laboratory, Department of Life Sciences, University of Mumbai, Santacruz (E), Mumbai -400 098, Mumbai, India.
^Corresponding author e–mail:mhfulekar@yahoo.com
ABSTRACT
Objectives: To determine the uptake and effects of heavy metals (Cd, Cu, Ni, Pb and Zn) on seed
germination, growth of fibrous roots, root/shoot growth and biomass of grass (sorghum) grown in soil -
vermicompost media (3:1).
Methodology and results: Vermicompost developed using vermiculture biotechnology from vegetable
market waste was characterized and found to have high concentrations of the nutrient elements Ca, Zn,
Cu, Mg, Fe and Mn. The vermicompost was used as a natural fertilizer for phytoremediation studies of
heavy metals. The selected heavy metals were dosed at concentrations from 0, 5, 10, 20, 40 and 50
ppm separately in the soil - vermicompost media (3:1) in pot experiments. The phytotoxic effect of
heavy metals on the growth of sorghum and physicochemical parameters of soil-vermicompost media
were measured. The uptake of heavy metals in plant samples were analyzed by atomic absorption
spectrophotometer. Plant growth was adversely affected by heavy metals at the higher concentration of
40 and 50 ppm, while lower concentrations (5 to 20 ppm) stimulated shoot growth and increased plant
biomass. Heavy metals were efficiently taken up mainly by roots of sorghum plant at all the evaluated
concentrations of 5, 10, 20, 40 and 50 ppm.
Conclusions and application of findings: Vermicompost from vegetable waste has high nutrient contents
and therefore it can be used as a natural fertilizer to increase growth of plants that play a role in
phytoremediation. Although heavy metals at 40 and 50 ppm reduced seed germination, plants
germinated and grew efficiently when Zn was available. Vermicompost application as a natural fertilizer
or soil amendment would enhance sorghum plant growth and enhance phytoremediation of heavy
metals from contaminated environments.
Key words
heavy metals, sorghum, phytoremediation, vermicompost.
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