Department of Environmental, Water and Earth Science, Tshwane University of Technology, Arcadia Campus, 175 Nelson Mandela Drive, Pretoria, South Africa; Natural Resources and the Environment, CSIR, PO Box 395, Pretoria, South Africa
Abia, A.L.K., Department of Environmental, Water and Earth Science, Tshwane University of Technology, Arcadia Campus, 175 Nelson Mandela Drive, Pretoria, South Africa; Ubomba-Jaswa, E., Natural Resources and the Environment, CSIR, PO Box 395, Pretoria, South Africa; Momba, M.N.B., Department of Environmental, Water and Earth Science, Tshwane University of Technology, Arcadia Campus, 175 Nelson Mandela Drive, Pretoria, South Africa
Many South Africans living in resource-poor settings with little or no access to pipe-borne water still rely on rivers as alternative water sources for drinking and other purposes. The poor microbial quality of such water bodies calls for appropriate monitoring. However, routine monitoring only takes into consideration the microbial quality of the water column, and does not include monitoring of the riverbed sediments for microbial pollution. This study sought to investigate the microbial quality of riverbed sediments in the Apies River, Gauteng Province, South Africa, using Escherichia coli as a faecal indicator organism and to investigate the impact of seasonal variation on its abundance. Weekly samples were collected at 10 sampling sites on the Apies River between May and August 2013 (dry season) and between January and February 2014 (wet season). E. coli was enumerated using the Colilert®-18 Quanti-Tray® 2000 system. All sites tested positive for E. coli. Wastewater treatment work effluents had the highest negative impact on the river water quality. Seasonal variations had an impact on the concentration of E. coli both in water and sediments with concentrations increasing during the wet season. A strong positive correlation was observed between temperature and the E. coli concentrations. We therefore conclude that the sediments of the Apies River are heavily polluted with faecal indicator bacteria and could also harbour other microorganisms including pathogens. The release of such pathogens into the water column as a result of the resuspension of sediments due to extreme events like floods or human activities could increase the health risk of the populations using the untreated river water for recreation and other household purposes. There is therefore an urgent need to reconsider and review the current South African guidelines for water quality monitoring to include sediments, so as to protect human health and other aquatic lives. © 2015 Elsevier B.V.
Effluents; Escherichia coli; Health risks; Pollution; Potable water; Rivers; Sediments; Surface waters; Wastewater treatment; Water pollution; Water quality; Water resources; Alternative water sources; Faecal indicator bacteria; Faecal indicator organisms; Faecal pollutions; Microbiological quality; Riverbed sediments; Seasonal variation; Wastewater treatment works; River pollution; river water; bioaccumulation; biomonitoring; coliform bacterium; concentration (composition); fluvial deposit; health risk; human activity; river bed; seasonal variation; sediment pollution; analytical equipment; Article; concentration (parameters); controlled study; dry season; environmental impact; Escherichia coli; feces microflora; flooding; health hazard; human activities; microbial quality; microbiological parameters; nonhuman; particle resuspension; population abundance; priority journal; quality control; river ecosystem; rural area; sampling; season; seasonal variation; sediment; South Africa; waste water management; water quality; water temperature; wet season; environmental monitoring; Escherichia coli; growth, development and aging; microbiology; river; sediment; water quality; Gauteng; South Africa; Bacteria (microorganisms); Escherichia coli; Environmental Monitoring; Escherichia coli; Geologic Sediments; Rivers; Seasons; South Africa; Water Microbiology; Water Quality