Abstract:
The population within Bongo and Kassena Nankana West Districts, in the Upper East
Region of Ghana is estimated to be about 84,545 and 70,667, respectively. An estimate of
about 80% of the population depends on groundwater for domestic and agricultural
purposes. However, groundwater resources in the Districts is at risk due to anthropogenic
activities such as rapid increase in irrigation activities and animals rearing, open defecation
and uncontrolled disposal of animal droppings, improper land use, waste disposal, and
illegal mining activities. “This study was carried out to use hydrochemical and isotopic
tracers to assess the impact of anthropogenic activities on groundwater quality in the study
areas. The study employed hydrochemistry and isotopic techniques to assess the chemical
quality of groundwater in the study areas. A total of sixty-four (64) boreholes were sampled
from the study areas for the study. The samples were analysed in-situ for pH, conductivity
and salinity using a HACH potable meter; and bicarbonate using a titrimetry. Analytical
methods employed for the determination of major and minor ions were (Na+ and K+)
complexometric titration (Ca2+) and (F-, Cl-, NO3
-, PO4
3-, and SO4
2-). Atomic absorption
spectrometry was used for the determination of Mg2+ and heavy metals (Fe, Mn and As).
Stable isotope of 2H and 18O composition of the water samples were determined using
Liquid-Water stable isotope analyser [Off-Axis Integrated Cavity Output Spectroscopy
(off axis ICOS) via Laser Absorption]. In general, majority of the ions are within the
permissible limit for drinking purpose except few locations in the study areas. The Gibbs
Diagram, the Piper Trilinear Diagram and the Hierarchical Cluster Analysis reveal
different degrees of water-rock interaction or mineralization and are consequence of
silicate weathering and silicate mineral dissolution, cation exchange and to a lesser extent
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fertilizer application. Based on the Water Quality Index (WQI) classification, the majority
of the samples fall under excellent to good water category and suitable for drinking water
purposes, except for groundwater in few areas which showed deteriorating water quality.
The stable isotopes composition implies, there has been fractionated before recharge”.
Since, the values deviate towards the positive valves.
