Assessment of the microbial quality of river water sources in rural Venda communities in South Africa

Abstract

The microbial quality of several, untreated surface water sources, used by rural communities in the Venda region of South Africa, was assessed to determine its safety for human consumption and to highlight the possible occurrence of water-borne diseases. The water sources studied were six sampling points on the Levubu River, Vuwani, Mutale, Ngwedi, Tshinane, Makonde, Mutshindudi and Mudaswali Rivers. Heterotrophic plate counts, faecal and total coliforms, enterococci and somatic coliphage counts were performed according to standard methods to determine the microbiological quality of the water sources. The presence of enteric pathogens such as Salmonella, Shigella, Campylobacter, Plesiomonas, Aeromonas and Vibrio was also determined. Results obtained showed that the minimum and maximum counts with regard to all the sampling points investigated were 1.5 x 103 cfu·ml-1 and 6.3 x 104 cfu·ml-1 for faecal coliforms, 6.0 x 102 cfu·ml-1 and 3.7 x 104 cfu·ml-1 for total coliforms, 1.8 x 102cfu·ml-1 and 1.3 x 106 cfu·ml-1 for heterotrophic plate counts, 1.0 x 101 cfu·ml-1 and 2.5. x 104 cfu·ml-1 for enterococci and 0 and 13 pfu·100 ml-1 for somatic coliphages. The results for the indicators were higher than the acceptable maximum limits prescribed by the Department of Water and Forestry of South Africa. According to these guidelines, the maximum values are as follows: 0 cfu·100 ml-1 for faecal coliforms, 5 cfu·100 ml-1 for total coliforms, 1.0 x 102 cfu·ml-1 for heterotrophic plate count, 0 cfu·ml-1 for enterococci and 1 pfu·100 ml-1 for somatic coliphages. Salmonella, Shigella, Vibro, Campylobacter, Aeromonas and Plesiomonasspecies were isolated from several of the water sources investigated. These untreated water sources are used for drinking and domestic purposes and pose a serious threat to the health of the consumers and therefore calls for urgent intervention by government. WaterSA Vol.28(3) 2002: 287-292