SOME HEAVY METALS IN PLANTS IRRIGATED WITH SEWAGE EFFLUENTS
SOME HEAVY METALS IN PLANTS IRRIGATED WITH SEWAGE EFFLUENTS
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Date
1989-07
Authors
MOHAMMED, Dahiru
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Abstract
This study investigates the concentrations of
certain metals absorbed by crops when irrigated with
sewage effluents. Amaranthus, tomatoes and maize
crops were flood-irrigated with A.B.U., Zaria waste
stabilization pond effluents for about 4 months at
application rate of 80 litres per day per plot of
4m x 2m. Tapwater was used as control irrigation
water.
The concentrations of heavy metals including Zn,
Mn, Pb, Cd and B in the sewage effluents and the
tapwater were determined, in addition to the initial
concentrations of these metals in the soil. Also, the
cumulative absorption of these metals in the various
parts of the experimental crops were determined during
the periods of irrigation.
It was found that A.B.U. sewage effluent contained
slightly more Zn, Mn, Pb, Cd and B than the tapwater.
Although the Pb, Cd and B concentrations absorbed by
various tissues of the test crops were more when the
crops were irrigated with sewage effluents than with
tapwater, the difference was not statistically
significant. However, the Mn concentrations absorbed
by various parts of the test crops were significantly
higher in the tapwater than in sewage effluents
irrigated crops.
The results show that different crops absorbed
these metals at different rates and that the absorption
of the metals differ from part to part for each
crop. Generally the roots of the test crops absorbed
the highest concentrations of Zn, Pb, and Cd followed
by stem. However, the Mn and B absorption were highest
in the leaves than the remaining parts in all the
test crops. The maize grains and the tomato fruits
contained the lowest concentrations of all the elements
investigated.
Although the heavy metal concentrations absorbed
by the different parts of the crops increased
(except Mn) with increasing sewage application, the
concentrations of these metals absorbed during the
period of study were within the permissible limits.
However, the effect of longer period of. investigation
on the absorption of these metals should be investigated.
Description
A Thesis submitted to the Postgraduate School,
Ahmadu Bello University, Zaria, in partial fulfillment
of the Requirements for the Award of the Degree of
Master of Science M.Sc.) in Water Resources and
Environmental Engineering.
Department of Water Resources
Ahmadu Bello University
Zaria - Nigeria
JULY, 1989
Keywords
HEAVY,, METALS,, PLANTS,, IRRIGATED,, SEWAGE EFFLUENTS