Assessment of groundwater quality using geoelectrical potential and hydrogeochemical analysis in Eha-Amufu and environs, Enugu state, Nigeria

Abstract

Presently, campaign for potable water supply is on the increase while the need to harness groundwater to alleviate the shortage of potable water is very crucial. This study investigated the groundwater potential of the local geologic formations and to determine the extent and distribution of the saline zones at Eha-Amufu. Integrated approach using geological, geoelectrical and hydrogeochemical investigations was adopted. Twenty-seven (27) vertical electrical sounding (VES) were performed at different locations within the area, using the Schlumberger electrode configuration with a maximum electrode separation of 600 m. Results from the VES revealed that the study area is made up of 3–6 geoelectrical layers, and are predominantly of QH and H curve types. The formations were observed to be characterized by low permeability zones/intervals, suggesting that Eha-Amufu could only possess perched aquifers table which supports the use of hand-dug wells. Hydro-chemical analysis of the ten (10) groundwater samples collected from different hand-dug wells indicated that the groundwater is characterized by Calcium (Ca)—Magnesium (Mg)—Chloride (Cl) water type, and could be classified as moderately hard to very hard. Water samples showed evidence of contamination with heavy metal such as Pb2+ beyond WHO standard, thereby making it unfit for domestic uses and consumption. Further result probe revealed that the local geology is the major process controlling the fate of groundwater chemistry in the area through weathering and rock–water interaction. Therefore, the present study proposes that other forms of portable water provisions should be explored such as harvesting and treatment of the various river resources in the area using purification plants and development of regional water conduits.