Effect of seasonal drawdown variations on groundwater quality in Nigeria

Water samples from twenty (20) shallow wells in Akure were analyzed during the wet and dry seasons in 2009 to ascertain the effect of drawdown on their qualities. Twenty (20) parameters consisting of five physical, twelve chemical and three heavy metals were tested for in the samples. The parameters included dissolved and suspended solids, turbidity, the pH, alkalinity, calcium, sulphate, nitrate, magnesium, electrical conductivity, lead, iron and manganese, were determined using standard procedures. Preliminary findings showed that 40% of the wells had poor drainage system and water levels expectedly varied significantly with seasonal change. However, most of the analysis showed significantly negative and weak correlations for the observed parameters during the two seasons of study. The revealed water quality was independent on drawdown but dependent on other parameters such as hygiene, pollution due to usage, underlying rock formation materials and proximity to polluting sources peculiar to emerging African cities.