O. OSARENOTOR

Groundwater remains a vital source of potable water in Benin city, yet its quality is decreasing in most parts of Nigeria. This study assessed the effect of on-site sanitation facility proximity on the physiochemical, total and fecal coliform load of groundwater from selected boreholes in Ikpoba Hill and Sapele Road, Benin City. Water samples are collected from four boreholes located within varying distances (11.8m in Ikpoba Hill to 32m in Sapele Road) from onsite sanitation facilities. In-situ measurements of pH, Electrical conductivity (EC), and total dissolved solids (TDS) were performed using a multifunction water quality meter, while nitrate and ammonia-nitrogen concentrations were determined using spectrophotometric methods. The pH values ranged from 4.3±0.01 in Ikpoba Hill to 5.2±0.5 in Sapele Road, indicating slightly acidic water across all samples. EC and TDS values ranged from (19±0 in Ikpoba Hill - 133±0µS/cm in sapele road) and (9±0 in Ikpoba hill - 66±0 mg/L in Sapele Road), respectively, reflecting low mineralization. Nitrate (0.46±0.11 in Sapele Road – 0.713±0.04 mg/L in Ikpoba Hill) and ammonia-nitrogen (0.85±0.17 in Ikpoba Hill – 1.50±0.77mg/L in Sapele Road). Aside from ammonia-nitrogen, other parameters were below NESREA permissible limits and there were no total or fecal coliforms detected in the samples. The observed differences between the mean physiochemical values were not significant (p>0.05). Aside from borehole C and D, the other boreholes (A and B) were sited well above the minimum distance (15m) from the nearest sanitary facilities (septic tank). It is recommended that sensitization be conducted to enlighten intending property owners with respect to the health implications of improperly siting water sources from onsite sanitation facilities.