Surface water quality of the North West Province based on physico–chemical properties and faecal streptococci levels
Molale, Lesego Gertrude.
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Water resources in the North West Province are characterised by an overall scarcity due to non–perennial rivers being the dominating water sources. However, increases in water demand from all social, environmental and economic entities have resulted in the inevitable deterioration of surface waters resulting in increasing threats of faecal and chemical pollution. The quality of 5 surface water systems in the North West Province was assessed by monitoring the physico–chemical properties of the water as well as the levels and diversity of faecal streptococci. The Mooi, Harts, Schoonspruit and Vaal Rivers were sampled during one warm–rainy season in 2010 and one cold–dry season in 2011. Dissimilarly, the opposite was employed for Barberspan as it was sampled during one cold–dry season in 2010 and one warm–rainy season in 2011. The average physico–chemical and microbial levels measured at some sites during both seasons were elevated and exceeded the acceptable South African Target Water Quality Range (TWQR) for full and intermediate recreational contact, livestock watering and irrigation. Seasonal variation patterns were observed in both physico–chemical and microbial levels. All surface water systems had relatively lower pH and electrical conductivity levels during the warm–rainy season as compared to the cold–dry season. In addition, water samples collected during the warm–rainy season from the Harts River, Barberspan and Vaal River had higher bacterial levels (total coliforms, faecal coliforms, E. coli and faecal streptococci) compared to samples collected during the cold–dry season. The Schoonspruit River had higher bacterial levels during the cold–dry season compared to the warm–rainy season. A total of 80 and 59 presumptive faecal streptococci isolates were obtained in 2010 and 2011, respectively. Biochemical tests and 16S rRNA gene sequencing were used to identify all faecal streptococci isolates. A total of 6 faecal streptococci species were identified and these included: Enterococcus faecium, E. faecalis, E. mundtii, E. casseliflavus, E. gallinarum and E hirae. Haemolysis and antibiotic resistant iii patterns were used for the characterisation of all faecal streptococci isolates. Of the 80 and 59 faecal streptococci isolates obtained, 32.5% and 6.8% displayed ?–haemolysis. Furthermore, dominant multiple antibiotic resistance patterns were observed for faecal streptococci isolates at most sites in both years. Faecal streptococci isolates obtained in 2010 were resistant to Penicillin G (10 ?g), Neomycin (30 ?g) and Vancomycin (30 ?g) and susceptible to Amoxicillin (10 ?g) and Streptomycin (300 ?g). Isolates obtained in 2011 were also resistant to Penicillin G (10 ?g) and Neomycin (30 ?g) but also to Amoxicillin (10 ?g) and Ciprofloxacin (5 ?g). Furthermore, the 2011 isolates were susceptible to Chloramphenicol (30 ?g) and Trimethoprim (2.5 ?g). The physico–chemical and microbial levels measured at several sites exceeded acceptable limits and proved unsuitable for applications such as full and intermediate recreational activities, livestock watering as well as irrigation. In addition, it appears that the physico–chemical and microbial levels were influenced by the season of collection. The multiple antibiotic resistance (MAR) phenotype data of faecal streptococci isolates obtained for the different sites suggests that their exposure history to several antibiotics was similar. This is most probably due to a uniform pollution pattern along the system. The presence and isolation of faecal streptococci, particularly those capable of causing ?–haemolysis, in surface water systems used for livestock watering and cultural activities is an important health care concern. The significance is outlined when the serious nature of the diseases and infections that could be caused by some of the pathogens (E. faecalis and E. faecium) isolated in this study as well as their emerging antimicrobial resistances is considered.