To determine groundwater quality at a basin level in climate-stressed, data-scarce basins, approaches need to be developed that go beyond traditional descriptive hydrochemistry and interpret the data to provide spatial indicators of water insecurity.
Groundwater samples were collected from 54 boreholes and hand-dug wells from the Sokoto Basin across the contrasting basement and sedimentary aquifer systems with the aim of providing an integrated assessment of the quality dynamics of the groundwater.
The combined investigation suggests that the composition of groundwater is mainly regulated by mineral weathering, rock-water interaction, evaporation-induced concentrations and locally derived human inputs.
The analysis integrates groundwater water insecurity, hydrochemical processes, spatial prediction and geological setting in a single analytical framework, providing a transferable approach to groundwater assessment in poorly monitored semi-arid groundwater settings.
The results offer scientific insights for early warning systems for specific monitoring and for enabling adaptive groundwater management, public health protection and progress towards SDG 6.
To determine groundwater quality at a basin level in climate-stressed, data-scarce basins, approaches need to be developed that go beyond traditional descriptive hydrochemistry and interpret the data to provide spatial indicators of water insecurity. Groundwater samples were collected from 54 boreholes and hand-dug wells from the Sokoto Basin across the contrasting basement and sedimentary aquifer systems with the aim of providing an integrated assessment of the quality dynamics of the groundwater. The methodological novelty is the simultaneous testing of controlling processes in a hydrochemical and heavy metal characterisation, quantification of spatial dependence through multivariate statistical analysis, variogram modelling, and ordinary kriging, resulting in the identification of contamination hotspots. The findings show significant variation between the different lithologies and different areas, with values being higher in the basement complex aquifers than the sedimentary aquifers, with respect to the concentrations of minerals such as Mn, Cr, Al, Zn and As. The combined investigation suggests that the composition of groundwater is mainly regulated by mineral weathering, rock-water interaction, evaporation-induced concentrations and locally derived human inputs. The geostatistical modelling also identified specific regions of hydrochemical hotspots, which were mainly located in low-lying locations and areas with high evaporative stress, suggesting that climate stress can enhance the accumulation of solutes. The analysis integrates groundwater water insecurity, hydrochemical processes, spatial prediction and geological setting in a single analytical framework, providing a transferable approach to groundwater assessment in poorly monitored semi-arid groundwater settings. The results offer scientific insights for early warning systems for specific monitoring and for enabling adaptive groundwater management, public health protection and progress towards SDG 6.
