Microbial drinking water quality of selected rural, peri-urban and urban communities and schools in the North West Province, South Africa

Abstract

Safe drinking water is a basic human right. This study mainly focused on the physico-chemical and microbiological drinking water quality of selected rural, peri-urban and urban communities and schools in the North West Province, South Africa. Parameters measured to determine the physico-chemical quality of drinking water were temperature, pH, total dissolved solids (TDS), electric conductivity, carbonate hardness, total hardness, NO2-, NO3- and chlorine. These parameters indicated hard water in the informal settlement (Sonderwater) as well as in the rural area (Ganyesa). Nitrate content were troubling for both areas, and total dissolved solids were higher than the standard in the water from Ganyesa. For microbiological quality of the water, heterotrophic plate count (HPC) bacteria, total coliforms, faecal coliforms, faecal streptococci, and staphylococci were enumerated on appropriate selective media using standard procedures. In the water from Sonderwater, faecal indicator bacteria were isolated, but none were found in the water from Ganyesa. Heterotrophic plate count bacteria and total coliforms were detected at levels above the standard in water samples from both areas. Staphylococci and faecal streptococci were present in low numbers in the water from both sites. Faecal coliforms isolated from Sonderwater showed multiple antibiotic resistances to beta-lactams. Identification of faecal coliforms from Sonderwater by API 20E strips and sequencing showed that they were Aeromonas spp. and Enterobacter spp.. Bacteria in the water from Sonderwater were tested for the potential to form biofilms. Scanning electron microscopy revealed multi-species biofilms developing in the water container after 5 days of storage. Water was sampled from four areas outside of Potchefstroom to determine a settlement gradient in water quality. Areas ranged from a formal area, through an established informal area and a newly established informal area to the newest established informal area. The water from these areas was classified as hard according to physico-chemical parameters measured, and TDS for the water from all areas were above the standard for domestic use. The established informal area had high numbers of total coliforms present in the water. Staphylococci and HPC bacteria were detected in levels higher than the standard for domestic use in all water samples. No faecal coliforms were found in the water from any of the areas. There was no visible gradient in the water quality between the areas. The water samples collected from rural, peri-urban and urban schools were also analysed in terms of physico-chemical and microbiological parameters. Water from all 2schools was classified as hard water. Only one school (peri-urban) had a pH above the standard. One rural school and one peri-urban school had TDS and electrical conductivity levels above the standard for domestic use. All rural and peri-urban schools had alarmingly high levels of nitrates present in the water. These schools receive groundwater as drinking water. Total coliform bacteria were present at high levels in all water samples from the schools. Rural and peri-urban schools presented levels of staphylococci and HPC bacteria higher than the standard for domestic use. Streptococci were present in water from some of the rural and peri-urban schools and one urban school. Faecal coliform/faecal streptococci ratios for rural schools indicated faecal pollution potentially of human origin, and in other schools faecal pollution from both human and animal origin. Before the vacation, faecal coliform bacteria were detected in water from all rural schools, two peri-urban schools and one urban school. After the vacation, faecal coliforms were only detected in water from two rural schools and one peri-urban school. Faecal coliforms identified and characterized showed multiple antibiotic resistances to beta-lactams, oxy-tetracycline and trimethoprim. Identification by API 20E strips and sequencing confirmed that faecal coliforms from schools were Escherichia coli and Klebsiella spp. It was concluded that water from Sonderwater were of poor quality and water from Ganyesa were acceptable with only the nitrates a troubling factor. There was no settlement gradient observed in terms of water quality between areas. Water from rural schools were generally of unacceptable quality in terms of both physico-chemical and microbiological parameters. The water quality of these schools was also very poor when compared to urban schools. Peri-urban schools had water quality better than rural schools, but poorer than urban schools. Surveys of water quality are recommended for all areas sampled, and education on the sanitary quality of water and related health implications is advisable for residents of informal and rural areas.