Hydrogeochemical Evaluation of Groundwater in Ibillo, Akoko-Edo Local Government Area, Edo State Nigeria

Abstract

Ibillo town, located in Edo State, Southsouth Nigeria, is an important agricultural and commercial center. In recent years, rapid development has created an increase in demand for groundwater and frequently facing water scarcity as well as quality problems. Hydrogeochemical evaluations of ionic abundance in groundwater systems in Ibillo was conducted by collecting a total of 50 groundwater samples for Dry and Rainy seasons, and were subjected to analysis for chemical and microbial characteristics. The study reveal that pH in the area is slightly acidic to alkaline ranging from 5.9 to 8.1. The electrical conductivity and total dissolved solids (TDS) values was noted higher during the rainy season. The abundance of major ions in the groundwater is in the order of K>Na>Ca>Mg =Cl>HCO3>SO4>NO3. Total hardness, Na, Fe, Mn, Cu, Cl, HCO3, SO4, NO3, Fl, NO2 and PO4 do not exceed the WHO permissible limit during both seasons. Ca and Mg in majority of the groundwater samples are within the permissible limit with few exceptions irrespective of seasons. K, Pb and Ni exceed the permissible limit during both seasons while Cr, Zn and Ba concentrations partially conform to the WHO limits irrespective of seasons. Most of the groundwater samples examined have high E. coli and total bacterial counts. A comparison of the results with relevant standards show that the water require various form of treatment to bring the microbial contents to standards required for domestic and industrial uses respectively. The type of water that predominates in the study area is Na-K-Cl type and mixed type. Besides, suitability of water for irrigation is evaluated based on sodium adsorption ratio, sodium percent and salinity hazard. It is observed that majority of samples irrespective of seasons fall in “excellent-good” zone indicating water is fit for irrigation purposes. The groundwater in this study area can be said to be partially good for industrial sectors but it require a little treatment for it to be completely suitable for industry.