Analysis of Water Quality Parameters and Heavy Metal Loading for Livestock Sustainability in Lake Gwakra, Girei LGA, Adamawa State, Nigeria: Multivariate and Weighted Index Approaches

Lake Gwakra, a vital livestock water source in semi-arid Adamawa State, Nigeria, faces escalating pressures from seasonal hydrological fluctuations and anthropogenic activities, yet its suitability for animal consumption remains inadequately characterized.This study conducted a comprehensive assessment using integrated Weighted Livestock Water Quality Index (LWQI) and Heavy Metal Pollution Index (HPI) to evaluate seasonal water quality dynamics.Monthly water samples (n=180) were collected over 12 months from five strategic locations, analyzed for physico-chemical parameters (pH, TDS, ions) via APHA (2017) methods and heavy metals (Fe, Mn, Cd, Cr, Ni, Zn, Pb, Cu) using ICP-MS.LWQI and HPI were computed against WHO/SON standards, with seasonal variations assessed via ANOVA and pollution sources identified through PCA and Pearson correlation.Results revealed a critical paradox: physico-chemical parameters exhibited excellent quality year-round (LWQI: dry season = 13.98;wet season = 14.31), confirming safe ionic composition and palatability.Conversely, HPI indicated severe contamination (dry season = 2716.7;wet season = 766.3),dominated by cadmium (90% contribution; dry season = 0.12 mg/L, 24× above livestock safety limits).Seasonal ANOVA confirmed significant wet-season increases in Mn (p=0.038) and Cd (p=0.014),linked to agricultural runoff and soil erosion.PCA identified three pollution drivers: natural hydrogeochemistry (PC1: EC, TDS, Ca²⁺, Mg²⁺), anthropogenic nutrient loading (PC2: BOD, PO₄³⁻, turbidity), and mixed geogenic-anthropogenic metals (PC3: Fe, Mn, Cr).Strong correlations (EC-TDS: r=0.94;Ca²⁺-Mg²⁺: r=0.88) and negative DO-BOD links (r=-0.67)validated these sources.The coexistence of excellent LWQI and critical HPI underscores the inadequacy of conventional water quality assessments in detecting heavy metal risks.Chronic Cd exposure threatens livestock health (nephrotoxicity, reduced productivity) and risks bioaccumulation in the food chain.Urgent interventions are needed: source control (fertilizer restrictions, riparian buffers), low-cost treatment (constructed wetlands), and integrated LWQI-HPI monitoring.This study provides a template for holistic water quality evaluation in livestock-dependent semi-arid regions.