SPATIAL ASSESSMENT OF GROUNDWATER QUALITY AND HYDROCHEMICAL INDICES IN ORE, SOUTHWESTERN, NIGERIA

Abstract

Millennium development goals are aimed at having sustainable safe drinking water and basic sanitation. Consequently an assessment of groundwater quality was carried out in Odigbo LGA of Ondo State,Nigeria to assess it for drinking, domestic and irrigation uses. Samples from 30 randomly selected ground watersources; shallow wells and boreholes were analyzed using APHA method. The results show that all the parameters are within the permissible limit of World Health Organization. The physico-chemical analysis of groundwater samples indicates that the dominant major cations are in decreasing order of Na⁺, Ca²⁺, Mg²⁺, K⁺ and the dominant anions are HCO^-₃, Cl^-, SO^-2₄, NO^-_3. The values of water quality index varies suggest a Good water (WQI of 50-75) accounts for 70% of the study area. The dominant groundwater facies revealed in this study are the non-carbonate alkali (primary salinity) exceeds 50% (zone 7); and transition zone with no one cation-anion pair exceeds 50% (zone 9), while evaporation; rock–water interaction, and precipitation; and silicate weathering process are the dominant processes in the hydrogeochemical evolution of the groundwater. In conclusion, the water in the study area are good/suitable for drinking, domestic and irrigation purposes with low equivalent salinity concentrate and moderate electrical conductivity.