Quality Assessment of River Water in Ogoloma-Okrika

Abstract

This study was carried out to determine the physicochemical and bacteriological quality at                        various points of the Ogoloma-Okrika River. Using composite sampling method, a total of 5                   samples were collected at 5 different points (human excrement point (OT), refuse dump point (OW), crude oil effluent discharge point (OO), upstream (OU) and downstream (OD) of the river).                      The total heterotrophic bacterial count obtained in this study  ranged from 7.0x104 cfuml-1 to 9.95x105 cfuml-1; total coliform 20-210 MPN/100 ml; faecalcoliform 6-53 MPN/100 ml;                          Vibrio 4x103 cfuml-1-1.78x105 cfuml-1. A total number of 36 isolates were obtained from the samples. The isolates belong to the genera: Acetobacter (7.7%), Erwinia (15.3%), Planococus (19.2%) Citrobacter (23.1%), Escherichia coli (19.2%), Vibrio (19.2%), Salmonella (4%) Shigella (15.3%), Enterobacter (7.7%), Kliebsella (7.7%). Temperature ranged from 27-28°C; pH, 4.97-6.82; electrical conductivity, 6020-6540 µs; alkalinity, 80-120 ppm; total dissolved solids (TDS) 2973-3725 mgL-1; dissolved oxygen (DO) 4.3-7.8 mgL-1; biochemical oxygen demand (BOD)2.5-3.5 mgL-1; chemical oxygen demand (COD) 3.2-4.9 mgL-1. Results indicate high faecal contamination of this important river used by a resident for domestic purposes. Concerns for public health safety are raised as most of the parameters monitored were found to be significantly higher than the WHO standards for safe water.