Investigating the hydrogeochemical processes and quality of water resources in Ojoto and environs using integrated classical methods

In an attempt to determine their suitability for consumption and irrigation uses, the prevailing hydrogeochemical processes and quality of both surface and groundwaters in Ojoto province, southeastern Nigeria were studied. Classical scientific methods and indicators such as hydrogeochemistry, stoichiometry, water quality index (WQI), and multivariate statistical analyses were integrated to achieve the research objectives. pH results classified most of the waters as slightly acidic. The order of dominance of the major cations and anions is Na+ > Ca2+ > K+ > Mg2+ and SO42- > Cl- > NO3- > HCO3-, respectively. The dominant water type is Na-Ca-SO4, and the dominant water facies in the area is sodium sulphate (Na-SO4), constituting about 54% of the total samples. Several hydrogeochemical, stoichiometric, and multivariate statistical analyses revealed that both anthropogenic inputs and geogenic processes (such as precipitation, silicate weathering, oxidation, and ionic exchange) influence the chemistry and quality of the waters. WQI of the waters showed that only 17.86% of the analyzed samples are of good quality for drinking purposes, whereas the quality of 53.57, 17.86, and 10.71% of the samples is poor, very poor, and unfit for use, respectively. Various irrigation suitability assessments (including salinity hazard, sodium absorption ratio, sodium percentage, residual sodium carbonate, chloro-alkaline indices, magnesium hazard, Kelly's ratio, permeability index, and potential salinity) conducted revealed that majority of the analyzed waters have poor irrigation quality.