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Heavy metal
concentrations in soils and accumulation in plants growing
in a deserted slag dumpsite in Nigeria
Mary B.
Ogundiran* and Oladele Osibanjo
Department of Chemistry, University of Ibadan, Ibadan,
Nigeria.
*Corresponding author: E-mail:
mbogundiran@yahoo.com.
Accepted 28 July, 2008 |
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Early detection and remediation of heavy metals in
soil and vegetation will ameliorate serious threats posed to
human existence. An auto battery manufacturing company
dumped slag containing proportion of heavy metals in an
hectare of land at Lalupon, Ibadan, Nigeria. The extent of
contamination of soil by heavy metals and their accumulation
in plants around the abandoned slag was studied. Plants and
the surrounding soils were sampled from different directions
at increasing distance from the vicinity of the waste pile
and their concentrations of heavy metals were determined.
The levels of Pb, Zn and Ni in mg/kg ranged from 34.8 –
41500, 16.3 – 849 and ND – 48.2; 9.2 – 9700, 16.0 – 271 and
2.83 – 36.9; 4.5-5670, 8.00 – 174 and ND – 322 in soil,
plant root and plant shoot, respectively. The plant samples
from the immediate environment of the waste were highly
contaminated with Pb. Six plant species, particularly
Sporobolus pyramidalis, met some of the conditions to be
classified as hyperaccumulators for Pb, Ni and Zn, and three
other plants fulfilled the criteria for heavy metal
excluders. We conclude that the potential hyperaccumulators
and excluders, under controlled conditions, can be used for
phytoremediation of the site.
Key words:
Heavy metals, contamination, hyperaccumulator, excluder,
phytoremediation. |
