Compendious evaluation of groundwater in parts of Asaba, Nigeria for agricultural sustainability

摘要

Abstract The hydrogeochemical evolution and irrigation suitability assessment of groundwater in selected parts of Asaba, Nigeria, has been conducted. The purpose of this study was to ascertain the hydrogeochemical relations and interactions of groundwater with rocks, and also assess the usefulness of the groundwater for irrigation purpose. Twenty (20) groundwater samples were analyzed for physical and chemical compositions. All tested water parameters were within the WHO (2017) recommended standard for drinking water except for Fe2+, which showed worrisome amount. Furthermore, hydrogeochemical plot with Piper trilinear diagram showed that groundwater samples in the study area is sodium bicarbonate and mixed water types and Schoeller semi-logarithmic plot showed an ionic trend of HCO3− + CO32− > Na+ + K+ > Mg2+ > Ca2+ > SO42− > Cl−. Langelier and Ludwig diagrams reveal that the hydrogeochemical evolution trend is towards the Cl−-SO42−-Na+ + K+ compositions. The indices of Chloro-Alkaline (CA) and Index Base Exchange (IBE) shows that the CA1 and CA2 are negative, implying that there is an exchange between (Na+ + K+) in the groundwater and (Ca2+ + Mg2+) of rocks. For the irrigation suitability, the SAR, %Na+, RSC, and MR ranged between 0.5 to1.49, 44.6 to 81.5, 0.48 to 2.02, and 9.61% to 98.8%, respectively. These imply that most of the tested groundwater could be used for irrigation purposes, while some are considered unfit for such. Therefore, regular routine assessment of the groundwater is recommended to ascertain its suitability for agriculture (irrigation) and domestic uses.