Hydrochemical characteristics and quality assessment of regolith aquifers in Enugu metropolis, southeastern Nigeria

摘要

Twenty groundwater samples were collected from Enugu metropolis over two seasonal periods in order to characterize the groundwater and to determine its quality for domestic and irrigation purposes. The results show that groundwater of the area is strongly acidic to slightly alkaline in nature and varied from "soft water" to "moderately hard" water type. The major ionic trend is in the order Cl~- ＞ Na~+ ＞ HCO_3~- ＞ K~+ ＞ Mg~(2+) ＞ Ca~(2+) ＞ SO_4~(2-)and Mg~(2+) ＞ Cl~- ＞ Na~+ ＞ K~+ ＞ Ca~(2+) ＞ HCO_3~- ＞ SO_4~(2-) in abundance for dry and rainy seasons, respectively. The results also reveal that there is an increase in trend of the ionic concentrations during the dry season, which arises from weathering of the host rocks and anthropogenic activities. Two hydrochemical facies were identified, namely, Na~+ _-K~+ _-Cl~- _-SO_4~(2-)and Ca~(2+) _-Mg~(2+) _-Cl~-_-SO_4~(2-). with Na~+ _-K~+ _-Cl~- _-SO_4~(2-) as the dominant facies for the two seasons. Groundwater quality ranges from "very poor water" to "good water" and "water unsuitable for drinking purposes" to "good water" for the dry season and rainy season investigations, respectively. The groundwater is suitable for irrigation purposes for the two seasons.