ABSTRACT
This study assessed the quality status of Eruvbi River using the National Sanitation Foundation Water Quality Index (NSFWQI). The study was carried out for a durations of three months. The physicochemical and biological parameters analyzed were pH, temperature, turbidity, total dissolved solids (TDS), phosphate (PO43-), nitrate (NO3-), biochemical oxygen demand (BOD), dissolved oxygen (DO), and total coliforms (TC). All parameters were analyzed using standard methods for temporal and spatial analysis. For each parameters the temporal and spatial range were pH (5.3-6.2), temperature (22-28oC), turbidity (5-128 NTU), TDS (20-128 mg/L), phosphate (0.11-0.97 mg/L), nitrate (0.2-0.8 mg/L), BOD (3.4-6.2 mg/L), DO (5-11.2 mg/L), while the mean for TC ranged from (416.9-295120.5 CFU/100 mL). The results were compared against World Health Organization (WHO), United States Environmental Protection Agency (US EPA), Nigerian Environmental Standards and Regulations Enforcement Agency (NESREA), and Nigerian Standard for Drinking Water Quality (NSDWQ) standards. The temperature, TDS and nitrate values were within the recommended WHO, US EPA, and NESREA standards for surface water. The TC counts were above the standards stipulated by all the agencies. The overall NSFWQI results indicated moderate water quality, with WQI values ranging from 54.04 to 61.95 at all sampling locations. The middle stream had the lowest NSFWQI value (54.04) caused by effluent discharge from a carbonated drink industry. The moderate water quality means that additional treatment is required before the water can be considered safe for drinking and domestic purposes. The NSFWQI values makes it easier to explain the water quality to the general public and decision makers, and it can be a valuable tool for water management.
