Effect of Seasonal Changes on Groundwater Quality in Sub-Urban Ibadan, Southwest Nigeria

The purpose of the study is to assess the levels of some physicochemical parameters and
heavy metals in water sources and quantify their possible impact. Household water
samples that include well water (n = 80) and treated municipal water (n = 3) collected
from March 2019 to March 2020 were analysed for 11 physicochemical properties using
instrumentation and classical methods. The estimated water parameters were first
compared with standard values for drinking water and then analysed spatially using
Inverse Distance Weighting (IDW) interpolation in ArcGIS software. Water quality
indices were also computed as a function of the potability of the water sampled. Through
this study, it was found that the well water samples were slightly acidic (pH 6.7+0.61)
while the concentration of nitrate (59.38 mg/L), sulphate (294.06 mg/L), cadmium (0.03
mg/L) and lead (0.13 mg/L) were above permissible limits in drinking water – 50 mg/L,
100 mg/L, 0.003 mg/L and 0.01 mg/L, respectively. The results indicate that more than
92% of the well water samples were unfit for drinking due to elevated concentrations of
nitrate, sulphate, cadmium, and lead. Findings from this study suggest prioritisation of
clean water provision to residents in the affected communities to avert a public health
emergency.
Keywords:
groundwater, physicochemical parameters,
heavy metals, geographic positioning system,
inverse distance weighting, water quality index