World Bank assisted National Agricultural Research Project (NARP) - University of Port Harcourt
Abstract
The surface and groundwater resources of the Ethiope river watershed
have been investigated for its hydrological and quality
characteristics. The results indicate that Ethiope River is perennial
and fed by groundwater seepages, precipitation and surface run-off from
adjacent areas. The lowest discharge rate of the river is recorded in
June and increases steadily reaching its peak in October. The
physico-chemical parameters of both water sources include, pH
(5.28-7.06), turbidity (1.16 \u2013 8.12 NTU), conductivity (65.00-
127.0 \u3bcs/cm), dissolved oxygen (4.40-7.60 mg/l) and total hardness
(25.50 \u2013 45.0 mg/l). Others include, Na+ (3.91 \u2013 27.05
mg/l), K+ (3.91 \u2013 8.73 mg/l), Ca2+ (3.21 \u2013 9.60 mg/l), Mg2+
(1.46- 5.84 mg/l), HCO3- (31.50-80.00 mg/l), Cl- (17.55 \u201335.10
mg/l), SO42- (0.25-0.58 mg/l), NO32- (0.19-0.55 mg/l) and PO42-
(0.20-19.00 mg/l). This physico-chemical quality is generally
compatible with WHO guideline for domestic use. Nevertheless, the water
samples consist of high microbial population including total coliform
bacteria counts (39.00 \u2013 1100 MPN/100ml) and Escherichia coli
(21.00 \u2013 305.00 MPN/100ml), which render both surface and
groundwater unfit for domestic use without disinfection. An assessment
of surface water-groundwater homogeneity using the parametric
student\u2019s t and F tests on selected constituents (chloride,
nitrate, sulphate, phosphate, sodium, potassium, calcium and
magnesium), indicate non-significance in the variation within the
tested parameters except for nitrate. This suggests some
groundwater-surface water intermixing or communication, and the
activity of denitrifying bacteria in surface water. A groundwater
pollution vulnerability assessment using DRASTIC model indicates
moderately high pollution risk level for the aquifer system