HYDROGEOCHEMICAL CHARACTERIZATION ASSESSMENT OF GROUNDWATER WITHIN IMICHAEL OKPARA UNIVERSITY OF AGRICULTURE AND ENVIRONS, UMUDIKE SOUTHEASTERN NIGERIA

Abstract

Groundwater serves as the primary source of potable water for Michael Okpara University of Agriculture, Umudike, and its surrounding agrarian communities in southeastern Nigeria. As population growth and more intensive farming increases, the demands for regular monitoring of groundwater quality are required to maintain long-term viability and protect health. Here, the hydrogeochemical properties, spatial patterns, and suitability of groundwater for both consumption and irrigation across the area are assessed. In total, eleven boreholes were methodically sampled and tested for key physicochemical indicators (pH, conductivity, and dissolved-solids content), major dissolved ions…, and trace elements (Cu, Mn, Cr, Cd, Pb, Zn, Fe, As, Mo, and V). Standard methods were applied for hydrochemical interpretation, such as Piper plotting, Gibbs plotting, and computation of the Sodium Adsorption Ratio (SAR); and contour maps were used to examine spatial differences. The findings show Ca–Mg–HCO₃ water types prevail, implying that interaction between water and the Benin Formation strongly shapes the chemistry. For major cations, the ranking is Ca > Mg > Na > K. Bicarbonate is the principal anion. Evaluation of the Gibbs plots points to rock breakdown by weathering as the key process controlling groundwater composition. In general, measured heavy metals are small in amount and lie within limits accepted by the WHO. Potentially harmful constituents, including Cd and Pb, were mostly not-detected, and only a few outliers hint at site-specific human-related contributions. Correlation testing indicates pronounced positive links for Fe with Cr (r = 0.958) and for Fe with Mn (r = 0.690), reinforcing mineral alteration as the dominant origin. Spatial plotting highlights clear spatial trends, with concentrated zones of Cr and As in the west-central area and a northwest-to-southeast decline for Zn. Even with these irregularities, the groundwater resource is, overall, largely free from contamination. Small SAR values demonstrate very good irrigation suitability and indicate no sodium-related risk. It is inferred that groundwater in the area shows chemical steadiness and is appropriate for household needs as well as farming. The results is an essential reference point for sustainable groundwater oversight and environmental surveillance within the region.