Abstract

The aim of this study was to examine and compare the levels of bacterial contamination in water obtained from the five river catchments in the North West Province with water quality guidelines. A total of 54 water samples collected during winter and summer seasons were cultured on m-FC and m-Endo agar plates using membrane filtration, and on Plate Count and Eosin Methylene Blue agar plates using spread-plate techniques. Biochemical characterisation of suspected Escherichia coli and Klebsiella isolates by Triple Sugar Iron (TSI) and serotyping using E. coli poly D1–D8 and Klebsiella capsular Types 1–6 antisera were performed for confirmatory identification. Results showed significantly high levels of contamination when using heterotrophic, total and faecal coliform counts as an indicator in all catchments in summer and winter seasons. In winter season, E. coli and Klebsiella were maximal in the Marico and Molopo catchment with 75 and 95% prevalence, respectively. The Crocodile and Elands and Marico and Hex catchments during summer also showed high levels of E. coli (63%) and Klebsiella (76%) contamination, respectively. Contamination levels were widespread and above the South African Department of Water Affairs’ guidelines for domestic, recreational and irrigation water were used. The consumption of such untreated water sources directly or indirectly, poses a health risk to consumers. Strict measures to ensure the discharge of properly treated effluent into the rivers should be put in place, to minimise the spread of potential pathogenic bacteria and the occurrence of water borne disease outbreaks.

Key words: River catchments, heterotrophic bacteria, total coliforms, faecal coliforms,Escherichia coli, Klebsiella, serotyping.