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Anthropogenic activities in catchments used for drinking water production largely contaminates source waters, and this may impact the quality of the final drinking water product. These contaminants may also affect taxonomic and functional profiles of the bacterial communities in the drinking water. Here, we report an integrated insight into the microbiome and water quality of four water treatment plants (NWC, NWE, WCA and NWG) that supply portable water to communities in South Africa. A new scoring system based on combined significant changes of physicochemical parameters and microbial abundance from raw to treated water was used to evaluate the effectiveness of the treatment plants at water purification. Physicochemical parameters which include total soluble solids, turbidity, pH, nitrites and phosphorus among others, were measured in source, treated, and distributed water. There were general statistically significant (P ≤ 0.05) differences between raw and treated water, demonstrating the effectiveness of the purification process. Illumina sequencing of the 16S rRNA gene was used for taxonomic profiling of the microbial communities and this data was used to infer functional attributes of the communities. Structure and composition of the bacterial communities differed significantly (P < 0.05) among the treatment plants, only NWE and NWG showed no significant differences (P > 0.05), this correlated with the predicted functional profile of the microbial communities obtained from Phylogenetic Investigation of Communities by Reconstruction of Observed States (PICRUSt), as well as the likely pollutants of source water. Bacteroidetes, Chlorobi and Fibrobacteres significantly differed (P < 0.05) between raw and distributed water. PICRUSt inferred a number of pathways involved in the degradation of xenobiotics such as Dichlorodiphenyltrichloroethane, atrazine and polycyclic aromatic hydrocarbons. More worryingly, was the presence of pathways involved in beta-lactam resistance, potential pathogenic Escherichia coli infection, Vibrio cholerae infection, and Shigellosis. Also present in drinking and treated water were OTUs associated with a number of opportunistic pathogens., Competing Interests: The authors have declared that no competing interests exist.

The operationalization of water resource protection initiatives for surface water resource quality and equitable water quality allocation is critical for sustainable socio-economic development. This paper assessed Blesbokspruit River Catchment's water quality status, using the South African Water Quality standards and Water Quality Index (WQI). Protection levels for quality, and waste discharge for point sources were set and evaluated using the total maximum daily loads (TMDLs) and chemical mass balance (CMB) techniques, respectively. The study found that the water quality results for the analysed physico-chemical parameters (Na+, Ca2+, Mg2+, Cl−, F−, pH, EC, SO42−) of the data collected from 2015 to 2022 were within the limits of the water quality standards, except for NO3− and PO42−. The water quality from the study area was categorized as acceptable for drinking purposes with the WQI of 54.80. The application of the TMDL approach resulted in the 77.96 mS/m for electrical conductivity (EC), 9.92 mg/L for phosphate (PO42−), and 15.16 mg/L for nitrate NO3− being set as the protection levels for the catchment. The CMB was found to be a useful tool for the evaluation of point source discharges into water resources. The study recommends the application of TMDL and CMB techniques in water resource protection practice. [ABSTRACT FROM AUTHOR]

National and regional water quality monitoring networks have been operated in South Africa since the early 1970s. These originally had text-based inventories that were convenient for specialists who were familiar with the national networks and knew the locations of their sites of interest. However, within two decades the networks had expanded in geographical extent and variables monitored to such an extent that users needed spatial context in order to locate sites that fitted their information requirements. Mapping applications running on the Internet, such as Google Earth and Leaflet, form the foundation of a system for providing online inventories and summaries of the data available on the water quality database. The interfaces were constructed using available software, mainly ArcInfo and R. A recent concern is a decrease in the collection of water quality data, which is reducing the value of data summaries for water resource management. [ABSTRACT FROM AUTHOR]

The South African national water quality database (Water Management System) houses data records from several environmental monitoring programmes, including the National Chemical Monitoring Programme (NCMP). The NCMP comprises an extensive surface water quality monitoring programme, managed by the Department of Water and Sanitation (DWS). The purpose of this technical note is to alert users to a systematic anomaly recently observed in the pH dataset of the NCMP, reflected in an abrupt increase between pre- and post-1990 data records. Although the cause of the anomaly in pH could not be confirmed with high confidence, an inappropriate acid rinse procedure in pre-1990 analytical methods was identified as the most likely cause, based on available evidence. This was supported by the variation in relative sensitivity when comparing the effect on waters with different buffering capacities, i.e., water with low buffering capacity (represented by total alkalinity < 10 mg/L, as CaCO3) showing the largest anomaly, compared with waters of higher buffering capacity (represented by total alkalinity > 30 mg/L, as CaCO3) showing the smallest anomaly. Historical pH data records in the NCMP (i.e. pre- 1990), therefore should be used with caution, especially in more weakly buffered systems. The possibility of reconstructing data using a correction factor derived from detailed statistical analyses of the post-1990 pH characteristics at selected sites is a possible solution that could be investigated in future. A key lesson learnt is the need to be diligent in capturing detailed meta-data on sampling procedures and analytical methods in datasets spanning several generations. Availability of such information is critical in order to provide users with a means of evaluating the suitability and comparability of data records in long-term datasets. The DWS includes such meta-data in the current version of the database, dating from about 1995 onwards. [ABSTRACT FROM AUTHOR]

Consumption of microbial-contaminated water can result in diarrheal illnesses and enteropathy with the heaviest impact upon children below the age of five. We aimed to provide a comprehensive analysis of water quality in a low-resource setting in Limpopo province, South Africa. Surveys were conducted in 405 households in rural communities of Limpopo province to determine their water-use practices, perceptions of water quality, and household water-treatment methods. Drinking water samples were tested from households for microbiological contamination. Water from potential natural sources were tested for physicochemical and microbiological quality in the dry and wet seasons. Most households had their primary water source piped into their yard or used an intermittent public tap. Approximately one third of caregivers perceived that they could get sick from drinking water. All natural water sources tested positive for fecal contamination at some point during each season. The treated municipal supply never tested positive for fecal contamination; however, the treated system does not reach all residents in the valley; furthermore, frequent shutdowns of the treatment systems and intermittent distribution make the treated water unreliable. The increased water quantity in the wet season correlates with increased treated water from municipal taps and a decrease in the average contaminant levels in household water. This research suggests that wet season increases in water quantity result in more treated water in the region and that is reflected in residents' water-use practices. [ABSTRACT FROM AUTHOR]

The article investigates the connection between transport, environment and food security in the rural area of Letaba district, South Africa. An overview on the transport of links between water quality, agriculture and regional development, is provided. It also highlights the impact of climate change to the crop yield in the area.

We review the current state of knowledge of quantified impacts of invasive alien plants on water quality, with a focus on South Africa. In South Africa, over 200 introduced plant species are regarded as invasive. Many of these species are particularly prominent in riparian ecosystems and their spread results in native species loss, increased biomass and fire intensity and consequent erosion, as well as decreased river flows. Research on the impact of invasive alien plants on water resources has historically focused on water quantity. However, although invasive alien plants also affect the quality of water, this aspect has not been well documented. Alien invasive plants increase evaporation rates, and reduce stream flow and dilution capacity. The biomass inputs of alien invasive plants, especially nitrogen fixers such as Acacia spp., alter nutrient cycles and can elevate nutrient concentrations in groundwater. Alien plant invasions alter the fire regimes in invaded areas by changing the size, distribution and plant chemistry of the biomass. More intense fires increase soil erosion and thereby decrease water quality. In contrast to riparian invasions, aquatic invasive plants have been more extensively studied in South Africa and their impacts on water quality have been relatively well monitored. Water quality in South Africa is rapidly deteriorating, and all factors that influence this deterioration need to be taken into account when formulating actions to address the problem. The changes in water quality brought about by alien plant invasions can exacerbate the already serious water quality problems. [ABSTRACT FROM AUTHOR]

Background: In low and middle income countries, public perceptions of drinking water safety are relevant to promotion of household water treatment and to household choices over drinking water sources. However, most studies of this topic have been cross-sectional and not considered temporal variation in drinking water safety perceptions. The objective of this study is to explore trends in perceived drinking water safety in South Africa and its association with disease outbreaks, water supply and household characteristics. Methods: This repeated cross-sectional study draws on General Household Surveys from 2002-2009, a series of annual nationally representative surveys of South African households, which include a question about perceived drinking water safety. Trends in responses to this question were examined from 2002-2009 in relation to reported cholera cases. The relationship between perceived drinking water safety and organoleptic qualities of drinking water, supply characteristics, and socio-economic and demographic household characteristics was explored in 2002 and 2008 using hierarchical stepwise logistic regression. Results: The results suggest that perceived drinking water safety has remained relatively stable over time in South Africa, once the expansion of improved supplies is controlled for. A large cholera outbreak in 2000-02 had no apparent effect on public perception of drinking water safety in 2002. Perceived drinking water safety is primarily related to water taste, odour, and clarity rather than socio-economic or demographic characteristics. Conclusion: This suggests that household perceptions of drinking water safety in South Africa follow similar patterns to those observed in studies in developed countries. The stability over time in public perception of drinking water safety is particularly surprising, given the large cholera outbreak that took place at the start of this period. [ABSTRACT FROM AUTHOR]

This paper reviews the progress made in the assessment of water resources in South Africa over the past 60 years by examining 5 major studies that were undertaken in this period. These studies illustrate how the exponential growth in computer power and the concomitant development of highly sophisticated tools have changed the manner in which our water resources have been appraised, allowing us to deal with more and more complex issues, including: water quality, surface water/groundwater interaction and the reduction in runoff due to afforestation and alien vegetation. However, the main concern today is the serious decline in hydrological monitoring in recent times. It is imperative that this decline be addressed, especially if we are to deal effectively with problems related to climate cycles and climate change, together with the deterioration in water quality. [ABSTRACT FROM AUTHOR]

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Water quality monitoring in the Olifants River catchment, Mpumalanga, is evaluated using river water dissolved sulphate levels, one of the best indicators of pollution related to acid mine drainage. Assessment of long-term water quality records shows that monitoring has not been carried out systematically. In that it fails one of the most fundamental criteria of good environmental monitoring practices. At some monitoring stations sampling frequency has been scaled down from approximately weekly to monthly intervals over time, despite evidence for increasing and problematic levels of pollution. At the Loskop Dam dissolved sulphate levels have increased more than 7-fold since the 1970s evidently due to increasing levels of pollution within the Little Olifants River catchment. At 4 of the 7 long-term monitoring stations river water sulphate levels exceed the 100 mg/e threshold value for aquatic ecosystem health most of the time for the duration of the record, and all of the time since about 2001. At these stations river water sulphate levels also exceed the 200 mg/ℓ threshold for human consumption 27 to 45% of the time, for the duration of the long-term record. These observations necessitate more frequent and improved monitoring, not evidently reduced efforts. A major concern is the location of a recently re-opened copper mine outside Phalaborwa, just upstream from the confluence of the Ga-Selati River and the Olifants River. Levels of copper sulphate, highly toxic to aquatic species, should be urgently investigated as a probable cause of recent fish and crocodile deaths in the Kruger National Park. In river systems subject to intensive mining activity, such as the Olifants River, toxic constituents such as copper, arsenic, chrome-VI, etc., currently not routinely measured by the Department of Water Affairs (DWA) need to be included in monitoring efforts as a matter of urgency. This will require drastic improvements in current water quality monitoring efforts, including the acquisition of modern analytical instrumentation. [ABSTRACT FROM AUTHOR]

Total microbial quality assessment and geographical information system were used for evaluating the quality of water and the spatial distribution of diarrhoea cases in Tshikuwi, a rural community in South Africa, during an outbreak of diarrhoea. The water-abstraction points included two groundwater storage tanks, namely Tank 1 and Tank 2 and the Khandanama river. Indicator microbial counts for total coliforms, faecal coliforms, enterococci, and heterotrophic bacteria exceeded the limit for no risk as stipulated by the South African water-quality guidelines for domestic use for Tank 1 and the Khandanama river. Vibrio, Salmonella, and Shigella species were prevalent in the Khandanama river. The spatial distribution of diarrhoea cases showed a hot-spot of diarrhoea cases close to Tank 1 and the Khandanama river. Results of chi-square analysis showed that the proportion of infection from each water source was different or that infection depends on the type of water source (α=0.05). The demonstrated spatial clustering of diarrhoea cases might have been influenced by the poor microbial quality of water used from Tank 1 and the Khandanama river. The results further highlight the urgent need of water-treatment facilities and monitoring of water quality in rural communities of South Africa. [ABSTRACT FROM AUTHOR]

Fracture apertures play a significant role in groundwater systems. For proper groundwater quantity and contamination management, fractures have to be properly characterised. However, due to their complexity, fracture characterisation is one of the main challenges for hydrogeologists all over the world. This is particularly important in South Africa, where aquifers are predominantly fractured. Two new methods have been developed to determine inclined and horizontal fracture apertures in fractured-rock aquifers. The first is a water-balance method, the slug-tracer (ST) test: • The slug-tracer (SI) test [b = (r²/R²) Δ h] and the second is a tracer-detection method, comprising the NAPL entry pressure (NEP) test and the NAPL injection pressure (NIP) test: • The NAPL entry pressure (NEP) test [b=1/2Pe-(rpgh)] • The NAPL injection pressure (NIP) test [b=1/2Pe-(pgV/2πr)] and [b=1/4Pe (Mg)/m] These mathematical formulations were developed from laboratory experimentation using transparent Perspex parallel plate physical models and 27 apertures of 0.008 mm to 6 mm, created by using aluminium foil and thickness gauges between 20 mm thick clamped Perspex plates. The ST test uses a slug to which is added NaCl as tracer (50 mg to 300 mg/ℓ). An EC meter is used to detect breakthrough in the observation boreholes. The NEP test uses an NAPL (sunflower oil) hydraulic head and transducers to determine the entry pressure. Using these mathematical formulae, fracture apertures are then determined for horizontal and inclined apertures. The NIP test uses the entry pressure (by injection), recorded by transducers of an NAPL (sunflower oil) and its volume or mass to determine the fracture aperture for horizontal and inclined fractures. Results from smooth and rough (buffed to 10 × 20 μ) fracture surfaces gave accuracies of 96 to 98% for aperture determinations of 26 apertures from 0.04 to 6mm. [ABSTRACT FROM AUTHOR]

The concept of water neutrality, based on its carbon equivalent, was first coined during the World Summit on Sustainable Development in 2002. Since then the term has been loosely used, with little quantitative validation. Here we present a first quantitative framework for a water-neutral scheme that allows a private water user to balance its water account through both demand- and supply-side interventions. Such innovative voluntary mechanisms can provide benefits in a chronically water stressed and developing country, such as South Africa. This scheme seeks to harness private sector investment in water security, by allowing investors to balance quantitatively their water account based on sound scientific rationale. Investors are required to engage in a three-step process of: reviewing their water usage, implementing a reduction strategy, and replenishment of water to hydrological systems through the investment in watershed services, equivalent to their water usage. Initially, the scheme allows participants to replenish quantitatively their water usage through investment in the clearing of water-intensive invasive alien plants. The project, however, encourages the innovation and development of further quantitative mechanisms for investing in watershed services, and proposes an operational model for the promotion of a water-neutral market in South Africa. [ABSTRACT FROM AUTHOR]

Water is considered an essential nutrient because the body cannot produce enough water itself, by metabolism of food, to fulfil its need. When the quantity or quality of water is inadequate, health problems result, most notably dehydration and diarrhoea. As a result of contaminated water and poor hygiene, related infections are still a serious problem. Indeed, in the South African setting water availability and sanitation are critical issues because of the prevalence of childhood diarrhoea and also the HIV/AIDS crisis. Though considerable efforts have been made to improve the water and sanitation problems in South Africa – especially with regard to water supply infrastructure – there is still room for much improvement. Water is a healthy alternative to calorie-dense, non-nutritive beverages, such as artificial fruit drinks and soda. The latter should be avoided as they contribute little other than energy and may contribute to overweight and obesity. Also, they displace more nutritious foods from the child's diet. Consumption of fruit juice should also be limited. These issues highlight the need for a specific guideline relating to water intake in the paediatric food-based dietary guidelines. [ABSTRACT FROM AUTHOR]

The assessment of water quality has turned to be an ultimate goal for most water resource and environmental stakeholders, with ever-increasing global consideration. Against this backdrop, various tools and water quality guidelines have been adopted worldwide to govern water quality deterioration and institute the sustainable use of water resources. Water quality impairment is mainly associated with a sudden increase in population and related proceedings, which include urbanization, industrialization and agricultural production, among others. Such socio-economic activities accelerate water contamination and cause pollution stress to the aquatic environment. Scientifically based water quality index (WQI) models are then essentially important to measure the degree of contamination and advise whether specific water resources require restoration and to what extent. Such comprehensive evaluations reflect the integrated impact of adverse parameter concentrations and assist in the prioritization of remedial actions. WQI is a simple, yet intelligible and systematically structured, indexing scale beneficial for communicating water quality data to non-technical individuals, policymakers and, more importantly, water scientists. The index number is normally presented as a relative scale ranging from zero (worst quality) to one hundred (best quality). WQIs simplify and streamline what would otherwise be impractical assignments, thus justifying the efforts of developing water quality indices (WQIs). Generally, WQIs are not designed for broad applications; they are customarily developed for specific watersheds and/or regions, unless different basins share similar attributes and test a comparable range of water quality parameters. Their design and formation are governed by their intended use together with the degree of accuracy required, and such technicalities ultimately define the application boundaries of WQIs. This is perhaps the most demanding scientific need—that is, to establish a universal water quality index (UWQI) that can function in most, if not all, the catchments in South Africa. In cognizance of such a need, this study attempts to provide an index that is not limited to certain application boundaries, with a contribution that is significant not only to the authors, but also to the nation at large. The proposed WQI is based on the weighted arithmetic sum method, with parameters, weight coefficients and sub-index rating curves established through expert opinion in the form of the participation-based Rand Corporation's Delphi Technique and extracts from the literature. UWQI functions with thirteen explanatory variables, which are NH3, Ca, Cl, Chl-a, EC, F, CaCO3, Mg, Mn, NO3, pH, SO4 and turbidity (NTU). Based on the model validation analysis, UWQI is considered robust and technically stable, with negligible variation from the ideal values. Moreover, the prediction pattern corresponds to the ideal graph with comparable index scores and identical classification grades, which signifies the readiness of the model to appraise water quality status across South African watersheds. The research article intends to substantiate the methods used and document the results achieved. [ABSTRACT FROM AUTHOR]

South Africa has always been subject to an arid climate, receiving only slightly more than half of the world's average precipitation. This precarious situation is further exacerbated by very high potential evapotranspiration and an extremely rapid population growth. This paper aims to evaluate the threats to the soil and water resources of South Africa. These resources are vital in ensuring sustainable food production. Physically, wind and water erosion, structural decay, subsoil compaction and soil surface crusting are of great concern. Chemically, acidification, salinization, and pollution are the main concerns; with acidification mainly limited to the humid eastern parts and salinization to the arid western parts of South Africa. Biological degradation is mainly driven by organic matter decline, reducing the already low soil organic carbon content of South African soils. The extent of organism decline and the concomitant pathogen increase is not that well-known. Water resources in South Africa are very limited and of variable certainty. Water use efficiency, especially in agriculture and forestry, should receive urgent attention, since these are the main consumers of this valuable resource. Sedimentation, salinization, and pollution constitute the main impacts on water quality. Water pollution arises mainly from point sources such as municipal effluent, with smaller impacts from industry and feedlots. Given the varied nature of institutions and role-players involved in soil and water degradation, it is vital that one or more national institutions take responsibility to monitor and at least attempt to rectify and/or manage the degradation of South Africa's soil and water resources. In this regard substantial financial support from the private sector would also be imperative. [ABSTRACT FROM AUTHOR]

Despite being a finite resource, both the quality and quantity of groundwater are under tremendous pressure due to rapid global changes, viz. population growth, land-use/land-cover changes (LULC), and climate change. The 6th Sustainable Development Goal (SDG) aims to "Ensure availability and sustainable management of water and sanitation for all". One of the most significant dimensions of the SDG agenda is the emphasis on data and governance. However, the lack of good governance coupled with good observed data cannot ensure the achievement of SDG6. Therefore, this study strives to evaluate water quality status and hydrochemical processes governing it in the data-scarce Mokopane area of South Africa. Groundwater is the main source of fresh water supply for domestic usage, intensive agriculture, and mining activities in Mokopane. In this study, hydrogeochemical analysis of groundwater samples was employed to calculate the water quality index (WQI) and evaluate factors governing water quality evolution in the study area. Statistical and spatial analysis techniques were carried out to divide sampling sites into clusters and delineate principal factors responsible for determining water quality of the sampled groundwater. Results suggest that most of the physico-chemical parameters are within permissible limits for drinking water set by the World Health Organization (WHO), except for high fluoride in some samples. Na-HCO3 is the most abundant water type followed by Mg-HCO3, which indicates dominance of Na+, Mg2+, and HCO3±. Rock-water interaction is the prime factor responsible for fluoride enrichment in water. The alkaline nature of groundwater favors the release of exchangeable F− from minerals like muscovite. The WQI suggests that 80% of water samples fall into the good and excellent categories. Poor management of untreated domestic sewage and agricultural runoff is a main factor for the bad/very bad categories of water samples. As the area lacks any credible scientific/government work to report water quality and its management aspects, the findings of this study will definitely help both scientific communities and policy makers to do what is needed for sustainable water resource management in a timely manner. [ABSTRACT FROM AUTHOR]

South Africa is facing population and climate-related challenges such as pressure on arable land, provision of clean and safe drinking water, and water-borne health problems. The devastating drought during 2014-2018 further amplified those problems and put additional pressure on already stressed water resources in the uMngeni River basin in the KwaZulu-Natal province. Even today, additional water is being transferred from the neighbouring basins to satisfy the needs of the rapidly increasing urban population. Understanding the impact of changing climate can lead to an increase in the region's resilience by providing direction for adaptation strategies. The uMngeni River basin supports two large urban centres, subsistence and intensive commercial agriculture, forestry, and dairy farming. Apart from the limited amount of water available in the catchment itself to support these activities, the usability of its waters is threatened by decreasing water quality, in particular nutrient enrichment and eutrophication due to the farming, old infrastructure, and improper solid waste management. A set of scientific tools (e.g. http://hypeweb.smhi.se/) helps the decision makers to understand how the water availability and nutrient loads might change in the future and to plan appropriate adaptation strategies. We present here climate impact indicators (CIIs) produced from the outputs of the HYPE model (Lindström et al., 2010) that quantify the changes in the simulated discharge and nutrients in the greater uMngeni River area projected due to climate change. We used climate data from 18 Global Climate Models (GCM's) developed at various institutions with different initial conditions (https://climate.copernicus.eu/) and emission scenarios (RCP4.5 and RCP8.5) to force the HYPE model. From these 18 GCM's, the six that adequately described the current local climate in the study area were used to quantify the CIIs. The period 2011-2100, broken into three 30-year segments was used to evaluate the impacts in the near future, mid-century, and far future as compared to the current period (1971-2000). Four out of the six models predicted deterioration in water quality, which might amplify the eutrophication problem. Eutrophication would impact human health, increase treatment costs, algal blooms; and possibly reduce agricultural land productivity. The change in total nitrogen concentrations was projected between -5 and 20% across all future periods but the percentage changes for phosphorus were generally higher than for nitrogen. The total phosphorus concentration is projected to change by -2 to 35%. The models also predicted a decrease in the water discharge of up to 40%, which would reduce drinking water availability and increase infrastructural costs. The decision makers need to identify the spatial patterns in order to implement mitigative measures like improvement of land management to reduce fertiliser demand, undertake solid waste management but also invest in water efficient technologies e.g., drip irrigation. Lindström G. et al. (2010). Development and test of the HYPE (Hydrological Predictions for the Environment) model – A water quality model for different spatial scales. Hydrology Research 41.3-4:295-319. [ABSTRACT FROM AUTHOR]

The aim of this study was to look at the changes in the water quality of Boskop dam over a period from 2000 to 2010 in order to use it as a baseline for any change in water quality that may occur if proposed mining activities take place. [ABSTRACT FROM AUTHOR]