Temporal Variability of Heavy Metals Concentration in Rural Groundwater of Benue State, Middle Belt, Nigeria

The influence of changes in season on heavy metal concentrations in rural groundwater of Benue State is investigated in this study. Water samples were collected from 26 rural community boreholes and analyzed for heavy metal concentrations as they affect the quality of drinking water based on the WHO standard and their variability for both wet and dry seasons. The analyses were carried out as prescribed in the standard methods for examination of water. The results of analyses show the mean values and CV% as follows: pH 7.55; 6.21% for wet season and 8.89; 4.24% for dry season. 414 µS/cm; 137.58% for wet season and 272.13 µS/cm; 94.92% for dry season; Fe 0.82 mg/L; 81.71% for wet season and 0.03 mg/L; 324% for dry season; Mn 0.73 mg/L; 52.05% for wet season and 0.14 mg/L; 92% for dry season; Zn 0.10 mg/L; 140% for wet season and 0.13 mg/L; 130.76% for dry season; Pb 0.74 mg/L; 75.68% for wet season and 0.04 mg/L; 170% for dry season; Cu 0.88 mg/L; 64.77% for wet season and 0.00 mg/L; 60% for dry season. Apart from pH and Zn whose values were higher in the dry season, other metals investigated had higher concentrations in the wet season. This implies that as climate becomes either wetter or drier due to phenomenal changes concentrations of heavy metals are likely to respond appropriately.