Assessment of groundwater quality: Physicochemical and bacteriological evidence from boreholes in Sangayan Diriya village, northeast Nigeria

The poor geology of Sangayan Diriya village has barred residents from getting access to water from the groundwater in their homes from time immemorial. This study was aimed at assessing the quality of boreholes sunk in close proximity to River Diriya wherein eight water samples were aseptically collected from the two available boreholes; borehole A (BA1, BA2, BA3 and BA4) and borehole B (BB1, BB2, BB3 and BB4). Standard procedures were employed for determining physicochemical properties, while pour plate method and most probable number (MPN) were used to estimate total viable bacterial counts and coliform count in the water collected, respectively. Results were compared with World Health Organization (WHO) guidelines and Nigerian Standard for Drinking Water Quality (NSDWQ) permissible standards. Results indicated pH, temperature, total hardness, turbidity, electrical conductivity (EC), sulphate, nitrate, alkalinity, calcium, magnesium and nitrate conformed to regulated standards, but mean phosphate concentration (1.79 mg/L) was above WHO allowable limit. However, out of the six heavy metals estimated in the water samples, i.e., Cadmium, Iron, Copper, Arsenic, Lead and Chromium, mean Iron concentration (1.16 mg/L) and mean Arsenic concentration (0.37 mg/L) were above allowable limits. The highest total viable bacterial count (6.3 × 104 CFU/mL) was recorded in BA2. Using the MPN method, BA4 recorded the highest coliform count (14 MPN/100 mL) while BB2 recorded the lowest coliform count (7 MPN/100 mL) each above WHO allowable limit. The findings in this study indicated that the water samples did not meet regulated standards and should be subjected to suitable treatment before drinking.