Evaluation of surface water quality using water quality index: A case study of Douglas Creek

Abstract

This study evaluates surface water quality of Douglas Creek. Physicochemical parameters of surface water samples for downstream and upstream sections were collected from Health Safety and Environmental Department of Network/Oando Exploration and Production Nigeria Limited’s (NEPNL) Production Facilities for the month of January 2020, to determine the level of pollution. Values were compared with the World Health Organization (WHO) and Nigerian Standard for Drinking Water Quality (NSDWQ). Physico-chemical parameters were used to calculate the water quality index (WQI) to ascertain suitability for human consumption and dissemination of wildlife and fish culture. According to (WHO) and (NSDWQ) standards, temperature (31.6 and 30.4 °C), EC (12498 and 11652 μs/cm), turbidity (226 and 196 NUT), DO (5.09 and 5.46 mg/l), TDS (7499 and 6991 mg/l), TSS (301 and 256 mg/l), chloride (4954 and 4321 mg/l), Pb (0.073 and 0.068 mg/l) and nickel (0.195 and 0.137 mg/l) were all above the permissible limits for drinking water. But pH (7.36 and 7.66), BOD (3.01 and 3.42), COD (6.44 and 8.53), Cu (0.07 and 0.05), Cr (0.001 and 0.001) and nitrate (8.76 and 9.52) were within the permissible limit for drinking water. Water quality index values of 735.913 at the downstream and 617.169 at the upstream sections of the creek were above the status of water for human consumption and dissemination of wildlife and fish culture. From literature, an index value of 100 and above indicates that water is unsuitable for human consumption and dissemination of wildlife and fish culture. Public awareness of this status needs to be raised for both human and aquatic life as well as wildlife safety