ANALYSIS OF CONCENTRATIONS OF SOME METALS IN STREAM WATER OF THE UPPER KUBANNI DRAINAGE BASIN, SAMARU-ZARIA
ANALYSIS OF CONCENTRATIONS OF SOME METALS IN STREAM WATER OF THE UPPER KUBANNI DRAINAGE BASIN, SAMARU-ZARIA
No Thumbnail Available
Date
1996-10
Authors
JEB, DAVID NYOMO.
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
ABSTRACT
The analyses of streamwaters of the Upper Kubanni Drainage Basin Samaru, Zaria
were carried out to determine the concentrations of six selected metals - Ca, Mg, Fe,
Cu, Zn and Pb from June to October, 1994.
As a result of the huge wastes generated due to the rapid process of urbanisation,
industrialisation, and agriculture, much concern has been placed recently on the
metal pollution of streamwaters used as sources of public water supply. This is
because of the severe impacts of the metals on health and the aquatic ecosystem.
However, studies relating to the chemical quality of water in the Upper Kubanni
basin have centred mainly on the A.B.U. reservoir, which is a source of domestic
water supply to the A.B.U. community. Some of these studies have revealed the
occurrences of chemicals such as Cl, F, I, No3, So4, Na, K, Ca, Mg, Fe, Zn, Pb and
Cu, in the A.B.U. reservoir water in varying concentrations (Ogunrombi, 1979;
Udoh et al, 1987). The concentration levels of Fe and Cu in the reservoir water have
significantly increased from about 2.88mg/l and below detection in 1982 to about
4.82mg/l and 0.28mg/l in 1992 (Yusuf, 1992). Therefore, increasing metal pollution
of the A.B.U. reservoir water and the non-evaluation of the chemical quality of
streamwater from sub-basins tributaries that empty into the A.B.U reservoir present
a major problem in identifying the sources and variations of metal pollutants into
the reservoir.
The major aim of the study therefore, was to identify the presence and
concentrations of the six selected metals in streamwaters of the Upper Kubanni
basin; and the variations in their concentrations between, the months of study
(temporal) and between the sub-basins (spatial); and, comparing the concentrations
of the metals from sub-basin with the International Standards for Drinking Water
and with the levels of the metals in the A.B.U reservoir water.
vii
The methodology for data collection was the use of basin out-lets that empty into
the A.B.U reservoir were chosen and monitored as sampling sites for water samples
collection. These sub-basins were, the Samaru (urban), Institute for Agricultural
Research-I.A.R. (rural/urban), and Kampagi Hill (rural). Water samples were
collected in clean plastic bottles (500ml) with screw caps, while river stage was
recorded during sample collection. Maps and air photos (1:50,000) were used to
determine the areas and drainage densities of the basins, and the total percentage of
rural or urban landuse areas of the basins. The concentrations of the metals were
determined in the laboratory using the Atomic Absorption Spectrophotometer
(A.A.S.) after digestion of the water samples by the Nitric acid Digestion Method.
The results of the laboratory analyses showed that the selected metals occur in the
surface water resources of the basin in varying concentrations. Statistical analyses
by means of one-way analysis of variance revealed that there were no significant
temporal variations in metal concentrations between the months of study and
significant spatial variations in mean total metal concentrations between the three
sub-basins, due to differences in catchment characteristics such as land use and
geological/geomorphological conditions.
Results of linear regression analyses showed that Fe in the Samaru and IAR subbasins,
Mg in the Samaru and Kampagi Hill sub-basins exhibited negative linear
relationships with river stage. However the relationships between metal
concentrations and river stage were not significant. Decrease in metal concentrations
with river stage were observed to be due to dilutions of the metals in stream water
during rising stages while increasing metal concentration with river stage were
observed to be due to increasing wash off of the metals from the basin into the
surface water resources. It was also observed that the non-significant relationship
between metal concentrations and river stage indicated that a rise or fall in river
viii
stage would not always signify a correspondent increase or decrease in metal
concentrations in the basin.
Concentrations of Ca, Mg, Cu and Zn compared with the WHO standards were
found to be above the recommended highest desirable levels for drinking water
while Cu concentration which was below detection level in the ABU reservoir water
prior to 1982 was found to occur in high concentrations (1.18mg/l, 0.59mg/l and
0.25mg/l in S, I.A.R and K.H. sub-basins respectively) above the W.H.O. standards.
Ca and Mg showed highest concentrations throughout the period of study and in the
three sub-basins. Different sources and activities are probable sources generating
these metals in the basin.
Thus, it was concluded that there is increase in metal pollution of the streamwaters
of the Upper Kubanni basin and consequently, the ABU reservoir water due to the
concentrations of these metals in the stream water and the increases in human
activities and changes in land use. The Samaru sub-basin was observed to be the
major source of severe pollution hazard to the ABU reservoir. Thus, given the
peculiar nature of and poor sanitary conditions especially in the Samaru township
sub-basin, specific recommendations on pollution abatement and control were given
to safeguard the quality of stream water in the Upper Kubanni basin. A critique of
the study was made and recommendations for further studies were also given.
Description
DEPARTMENT OF GEOGRAPHY
ADHMADU BELLO UNIVERSITY
ZARIA.
Keywords
ANALYSIS,, CONCENTRATIONS,, METALS,, STREAM,, WATER,, UPPER,, KUBANNI,, DRAINAGE,, BASIN,, SAMARU-ZARIA.