Assessment of Physicochemical and Microbial Parameters in Groundwater Around Solid Waste Dumpsite at Egbelu, Rivers State, Nigeria

This study assessed the physicochemical and microbial quality of groundwater around a solid waste dumpsite at Egbelu, Rivers State, Nigeria. Groundwater from twelve boreholes (three per distance) was sampled once at 100 m, 300 m and 500 m from the dumpsite, with boreholes at 800 m as the control. Parameters analysed were pH, temperature, electrical conductivity (EC), total suspended solids (TSS), total dissolved solids (TDS), turbidity, nitrate, phosphate, total heterotrophic bacteria (THB) and total heterotrophic fungi (THF). Data were analysed using analysis of variance (ANOVA), Pearson correlation and principal component analysis (PCA). pH (6.35–6.69) remained within WHO and NSDWQ limits. Temperature declined from 29.60 °C at 100 m to 28.20 °C at 800 m, EC from 98.33 µS/cm (100 m) to 70.80 µS/cm (500 m). Nitrate and phosphate peaked near the dumpsite (5.31 and 2.61 mg/L). THB peaked at 706,667 ± 271,538.80 CFU/mL at 100 m, while THF declined from 60,000 ± 43,588.99 CFU/mL at 100 m to 3,333.33 ± 5,773.50 CFU/mL at the control. Distance correlated negatively with temperature (r = −0.999), phosphate (r = −0.992) and THF (r = −0.83). PCA showed that PC1 (49.88% of variance) was driven mainly by nitrate, EC, turbidity, pH, temperature and phosphate, while PC2 (38.84%) separated TSS and TDS, which were unrelated to distance, from temperature and phosphate. The findings suggest a dumpsite influence on groundwater quality, particularly at close range, although overall ANOVA differences across distances were not significant; the trends are therefore indicative and have potential public health implications.