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The quality of surface water has a significant impact on human health and the entire ecological system. Sewer spillages from the surrounding informal settlements discharging into the river, carrying high concentrations of fecal coliforms, are one of the major causes of extreme pollution in the rivers of South Africa. These informal settlements are common in many developing countries, and they are usually located near waterways to compensate for basic demands for water, sanitation, and recreational space, where municipal infrastructure lags behind urban growth. One major problem has been poor sanitation and poor waste disposal practices in the informal settlements, which has led to the contamination of water resources. This study aims to assess the extent to which poor sanitation in informal settlements impacts the water quality of South African rivers, given the rapid rise in population and unemployment rate. The study also highlights health and environmental issues in the local regions caused by poor sanitation. Contamination of water bodies is associated with serious health problems and fatalities. Therefore, there is a need for frequent monitoring and management of waste products discharged into the neighboring aquatic environments. [ABSTRACT FROM AUTHOR]

This study focused on assessing the extent of pollution in both flowing and non-flowing surface water within the Matjhabeng mining area of South Africa, with particular emphasis on the substantial impact of gold mine tailings. A comprehensive analysis of physical water-quality attributes, including potentially toxic elements (PTEs), and relevant pollution risk indices was undertaken. To comprehensively elucidate the potential risks to aquatic organisms and human health, a risk assessment framework predicated upon the source–pathway–receptor model was developed. Principal Component Analysis (PCA) was employed as a multivariate statistical tool to discern the potential origins of PTE contamination within the environment. The results substantiate pronounced pollution manifestations within the surface water milieu of the Matjhabeng mining area. Specifically, concentrations of critical PTEs, such as arsenic, cobalt, copper, iron, selenium, and zinc, exhibited transgressions of the regulatory thresholds stipulated by both the South African Department of Water Affairs and Forestry (DWAF) and the Canadian Council of the Ministers of the Environment (CCME). Additionally, concentrations of the aforementioned elements exceeded the stipulated DWAF guidelines for irrigation water usage. Pollution indices, encompassing the Single-Factor Pollution Index and the Nemerow Integrated Pollution Index, discerned moderate contamination stemming from As, while remarkably elevated pollution levels were identified for selenium. PCA elucidated 94.5% of the aggregate variance, revealing cobalt, copper, nickel, and zinc as coalescing within PC1, indicative of a common anthropogenic provenance that is conceivably linked to historical gold mine tailings. PC2 exhibited an aggregation of chromium, iron, and lead, reaffirming this shared anthropogenic etiology. The third PCA component was characterized by selenium, followed by arsenic and magnesium in the fourth. The resultant PTE contamination underscores a profound ecological and public health risk, impacting both the aquatic ecosystems and the local community within the precincts of the Matjhabeng Local Municipality (MLM) area, with consequential amplification of susceptibilities to deleterious health consequences. Urgent and concerted interventions are imperative to ameliorate the emergent decline in surface-water quality within the MLM locale. The adoption of nature-based remediation paradigms holds promise for efficaciously elevating water quality, ameliorating community health, and underpinning the long-term economic viability of the region. [ABSTRACT FROM AUTHOR]

Excessive discharge of poorly treated effluent has impacted global water resource systems intensely. The declining state of wastewater treatment plants (WWTPs) is a significant source of pollution in water resources. There is evidence of water resource quality deterioration in natural environments caused by effluent discharges. We assessed the impact of wastewater treatment effluent on the quality of the Crocodile River. For spatial distribution, we collected data from three WWTPs discharging effluent into the Crocodile River and from three points situated downstream of each WWTP. Physicochemical and microbiological parameters such as pH, electrical conductivity, chemical oxygen demand, phosphates, nitrates, ammonia, and Escherichia coli were analysed using standard methods of the American Public Health Association. The water quality index was also calculated to give an overall indication of pollution within the catchment. The results show that WWTPs were not complying with the effluent standards set out in their water use licence. The WWTP effluent had a negative impact on downstream water quality, with the water quality index indicating low quality of discharged effluent. It is recommended that a regular and consistent water resource quality monitoring programme be implemented, particularly in areas where effluent discharges are prevalent. In many African nations, water pollution is a serious problem that may be traced to a variety of sources. Surface water pollution has adverse effects on aquatic ecosystems and reduces the availability of clean water. In most semi-arid to dry southern African regions (e.g. South Africa), water scarcity is a significant concern. In these regions, water is a vital resource that must be protected at all times, given that the inadequate infrastructure of wastewater treatment facilities adds to the decline in South Africa's water quality standards. [ABSTRACT FROM AUTHOR]

Rivers in the North West Province (NWP) of South Africa are polluted by various anthropogenic activities that are associated with agricultural, domestic, industrial, and mining activities. Pollutants and effluent resulting from these activities impact the physico-chemical and biological characteristics of river water. More particularly, domestic and agricultural pollution has been associated with the occurrence of pathogenic yeast species in water. The aim of this study was to determine physico-chemical parameters, yeast levels, and the antifungal susceptibility of pathogenic yeasts in river water. Physico-chemical parameters and yeast levels were determined using standard procedures. Yeasts were identified by biochemical tests and 26S rRNA gene sequencing. Disc diffusion antifungal susceptibility tests were conducted on identified potential pathogenic yeasts. Physico-chemical parameters were within target water quality ranges (TWQR) for livestock farming but were mostly out of range for irrigation. Yeast levels (incubation at 37°C) ranged from 363 to 1 778 CFU/L. There were significant differences (p < 0.05) in the physico-chemical parameters and yeast levels between some seasons and among the river systems under study. A positive association was observed between temperature, COD and yeast levels in all the river systems. Ascomycetes, which were the most prevalent isolates, were identified as Candida spp. (35%), Pichia spp. (13%), Cyberlinera spp. (12%), Meyerozyma spp. (11%), Clavispora spp. (10%), Saccharomyces spp. (6%), Kluyveromyces spp. (5%), Yamadazyma spp. (4%), Trichosporon spp. (3%), and Wickerhamomyces spp. (1%). Antifungal resistance of the potential pathogenic yeasts was as follows: flucytosine and miconazole (100%) > fluconazole (78.5%) > econazole, and miconazole and ketoconazole (49.6%) > nystatin (15.2%). The river water systems explored in the study are used for agricultural, domestic and recreational purposes. Direct contact with the water, especially by immune-compromised people, may pose a health threat and should be further investigated. [ABSTRACT FROM AUTHOR]

Bacterial communities in human-impacted rivers and streams are exposed to multiple anthropogenic contaminants, which can eventually lead to biodiversity loss and function. The Wonderfonteinspruit catchment area is impacted by operational and abandoned gold mines, farms, and formal and informal settlements. In this study, we used 16S rRNA gene high-throughput sequencing to characterize bacterial communities in the lower Wonderfonteinspruit and their response to various contaminant sources. The results showed that composition and structure of bacterial communities differed significantly (P<0.05) between less (downstream) and more (upstream) polluted sites. The taxonomic and functional gene dissimilarities significantly correlated with each other, while downstream sites had more distinct functional genes. The relative abundance of Proteobacteria, Bacteroidetes and Actinobacteria was higher at upstream sites, while Acidobacteria, Cyanobacteria, Firmicutes and Verrucomicrobia were prominent at downstream sites. In addition, upstream sites were rich in genera pathogenic and/or potentially pathogenic to humans. Multivariate and correlation analyses suggest that bacterial diversity was significantly (P<0.05) impacted by pH and heavy metals (cobalt, arsenic, chromium, nickel and uranium). A significant fraction (~14%) of the compositional variation was explained by a combination of anthropogenic inputs, of which mining (~6%) was the main contributor to bacterial community variation. Network analysis indicated that bacterial communities had non-random inter- and intra-phyla associations and that the main taxa showed both positive and negative linkages to environmental parameters. Our results suggest that species sorting, due to environmental parameters, was the main process that structured bacterial communities. Furthermore, upstream sites had higher relative abundances of genes involved in xenobiotic degradation, suggesting stronger removal of polycyclic aromatic hydrocarbons and other organic compounds. This study provides insights into the influences of anthropogenic land use on bacterial community structure and functions in the lower Wonderfonteinspruit. [ABSTRACT FROM AUTHOR]

We performed a scientometric analysis of water research publications extracted from four decades of South African related papers to identify paradigms and paradigm shifts within water research in South Africa. Between 1977 and 1991, research publications are dominated by research into technical and engineering solutions, as well as designs and plans to secure water supply. From 1992 to 2001, publications on water pollution, water quality, water resource management and planning are prominent. The second major paradigm is observed from 2001 to 2011 in which the emphasis is on planning, modelling, catchment-scale studies and a multidisciplinary approach to research. Another transition period, towards the end of 2011, is characterised by uncertainty, although it also shows the prominence of key concepts such as participation, governance and politics in water management. The second aim of this study was to identify and prioritise current and future water research questions through the participation of a wide range of researchers from across the country, and to relate these questions to research paradigms, issues and concerns in water in South Africa. Over 1600 questions were collected, reduced in number and then prioritised by specialists in the water sector. The majority (78%) of questions offered by respondents in the South African case study dealt with relatively short- to medium-term research requirements with 47% of questions focused on medium-term issues such as supplying water, service delivery and technical solutions. [ABSTRACT FROM AUTHOR]

Biological monitoring tools are largely lacking for many countries, resulting in adoption of tools developed from other countries/regions, but in many instances, their applicability to the new system has not been explicitly evaluated. The objective of the study was to test the applicability of the South African Scoring Systems Version 5 (SASS5) to urban streams in Zimbabwe. The study evaluated the relationship between water quality variables and SASS5 indices/metrics [(SASS and average score per taxon (ASPT)] and found high degree of concordance between water chemistry parameters and SASS5 metrics, indicating that both SASS and ASPT scores are sensitive to detect environmental changes. This result can be attributed to occurrence of ubiquitous macroinvertebrate taxa sharing similar environmental tolerances with those recorded for South African systems. The applicability of SASS5 metrics need to be tested across different geographical and climatic regions in the country (taking into consideration seasonal variations that are important drivers of benthic faunal assemblages in lotic systems) and disparities among the regions compared for the adoption of the index in the entire country. The SASS5 metrics can also be further strengthened by (a) taking into account the relative abundance of taxa and (b) also improving on its ability to reflect other forms of perturbations besides eutrophication and organic pollution such heavy metal pollution. [ABSTRACT FROM AUTHOR]

This paper discusses concentrations of 5 essential trace metals (chromium, copper, iron, manganese and zinc) in water, sediment and various fish (C. gariepinus) tissues. With the exception of high Zn concentrations in skin, the highest essential element metal concentrations were generally recorded in liver and gill arch tissues, followed by gill filaments and lastly skin and muscle. This general trend is in agreement with trends reported by other workers. Fe concentrations were found to be significantly higher at the Vaal Dam more often than at the Vaal Barrage. In comparison, Mn concentrations were higher at the Vaal River Barrage more often than at the Vaal Dam. No clear trends emerged with regard to differences between localities for the other metals, or between surveys/seasons for all essential trace metals examined. The likely reason for the lack of distinct trends is the amount of variability observed in tissue metal concentrations within localities and seasons in this study. Such variability is also reflected in current literature and accentuates the importance of both abiotic (e.g. physical water quality variables) and biotic (e.g. host physiological status, general biology and life history traits) factors influencing the concentrations and bioavailability of trace metals. [ABSTRACT FROM AUTHOR]

Scenarios of present, intermediate and future climates for Southern Africa were analysed to evaluate potential changes in hydrologically relevant statistics of rainfall that could be observed this century as a result of climate change. These climate scenarios were developed in previous studies by applying empirical downscaling techniques to relatively coarse-scale climate scenarios simulated by general circulation models (GCMs) as part of the Intergovernmental Panel on Climate Change 3rd and 4th Assessment Reports (TAR and AR4, respectively). The regional climate scenarios were available at a daily time-step and for a spatial grid resolution of 0.25° over Southern Africa, comprising South Africa, Lesotho and Swaziland. In the study, the regional climate scenarios were related to the 1946 quaternary catchments in the region since the possible hydrological impacts of climate change will ultimately be assessed explicitly by applying the regional climate scenarios in a daily time-step hydrological model. The analysis of potential changes in hydrologically relevant rainfall statistics was qualitative in nature and focused on determining where convergence exists amongst the different climate models with respect to changes in rainfall, and what the likely hydrological implications would be for the region. According to all of the GCMs evaluated in the study, more rainfall is projected for the east of the region. The greater rainfall projected for the east would be in the form of more rain days and more days with bigger rainfalls. If these scenarios are correct, the combination of wetter antecedent conditions and larger rainfall events would result in more runoff being generated and this would have implications for, inter alia, filling of dams and water quality. According to all of the GCMs evaluated, less rainfall is projected along the west coast and the adjacent interior, with the possibility of a slight increase in inter-annual variability, If correct, this would result in a decrease in flows and an increase in flow variability, since changes in precipitation are amplified in the hydrological cycle. As convergence in climate-change scenarios becomes apparent, there is now an arguable basis for developing appropriate response strategies for incorporation into adaptation policy. Perhaps one of the greatest challenges in this regard is now to explore the issues of uncertainty and probability in order to develop a more rigorous basis to enable proactive responses. [ABSTRACT FROM AUTHOR]

Discharges from informal settlements cause numerous adverse water quality impacts on urban areas and on receiving waters. These problems reflect local conditions with respect to economic development, level of environmental protection (including the associated infrastructure), institutional arrangements and public awareness. Development of comprehensive tools for selection of drainage management interventions, even at planning levels, is still at its early stages in South Africa. Municipalities in South Africa face many challenges in identifying, assessing and selecting the right interventions and/or strategies to address the impacts of land use on receiving waters. A spreadsheet-based model was developed in this study specifically to assist in identifying, selecting and evaluating interventions to manage storm- and grey-water quality. The model also consists of modules: to quantify water quality management objectives (load reduction targets) of pollutants of concern, to formulate implementation strategies by combining different mixes of interventions at different levels of implementation, and to cost and select the optimum management strategy. In the Alexandra settlement investigated, the identified interventions to achieve management objectives optimally consist of educational programmes, erosion and sediment control, street sweeping, removal of sanitation system overflows, impervious cover reduction, downspout disconnections, removal of illicit connections to storm drains, establishment of riparian buffers, use of rainwater tanks and exfiltration systems. [ABSTRACT FROM AUTHOR]

Epilithic diatom Communities offer a holistic and integrated approach for assessing water quality as they remain in one place for a number of months and reflect an ecological memory of water quality over a period of time. The objective of this study is to use diatom assemblages to distinguish between particular land types and associated water quality impacts that are linked to these land-use patterns. Water quality and diatom community data were collected from sites in the Crocodile and Magalies Rivers (Gauteng and North West Province, South Africa) associated with agricultural, urban and natural (reference) adjacent land use respectively. The data collected were subjected to multivariate statistical techniques to analyse spatial and temporal patterns in water quality (principal component analysis) and diatom community structures (non-metric multidimensional scaling) to elucidate hypothesised differences in community structure per land-use type. Five diatom response indices (Generic Diatom Index, Specific Pollution Sensitivity Index, Biological Diatom Index, Eutrophication/Pollution Index and Percentage Pollution Tolerant Valves) incorporated in the OMNIDIA software were implemented to assess the integrity of diatom communities per land-use type. Principle component ordination of water quality describes 56.6% of the variation in data observed, and indicates the separation of reference sites from test sites for low and high flow conditions combined. It was, however, not possible to distinguish between the agricultural and urban land-use sites using PCA based on water quality data. One-way ANOSIM showed a significant difference (p < 0.05) between reference groups, agricultural groups and urban groups, with no significant differences noted (p> 0.05) between groups made up of sites exhibiting the same land-use patterns. Diatom indices showed that agricultural sites were in a slightly more modified ecological state than urban sites overall. Based on the species similarity (SIMPER analyses), reference sites showed strong associations with Achnanthes minutissima, Gomphonema venusta and Cocconeis placentula var. euglypta, whilst urban sites were associated with Diatoma vulgaris, Navicula tripunctata and Amphora pediculus. Agriculture could be separated into high- and low-intensity practices based on species composition. Sites where high-intensity agriculture took place were dominated by motile species of the genus Nitzschia, and low-intensity agriculture was indicated by motile species of the genus Navicula. Urban sites contained a combination of species that were tolerant of spikes in water quality. [ABSTRACT FROM AUTHOR]

Emergent vegetation along the banks of a river channel influences its conveyance considerably. The total channel discharge can be estimated as the sum of the discharges of the vegetated and clear channel zones calculated separately. The vegetated zone discharge is often negligible, but can be estimated using established methods if necessary. The clear channel discharge can be estimated either through application of a resistance equation using a composite resistance coefficient, or by integration of the transverse distribution of the depth-averaged velocity. Recommendations are made for estimating the composite resistance coefficient, and the coefficient for the vegetation interface. An equation for the integrated velocity distribution is also presented, together with a procedure for its application. The methods reliably reproduce resistance coefficients and conveyances measured in laboratory channels. [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]

There is continuous deterioration of freshwater systems globally due to excessive anthropogenic inputs, which severely affect important socio-economic and ecological services. We investigated the water and sediment quality at 10 sites along the severely modified Swartkops River system in the Eastern Cape Province of South Africa and then quantified the phytoremediation potential by native and non-native macrophyte species over a period of 6 months. We hypothesized that the presence of semi and permanent native and non-native macrophytes mats would reduce water and sediment contamination through assimilation downriver. Our results were variable and, thus, inconsistent with our hypotheses; there were no clear trends in water and sediment quality improvement along the Swartkops River. Although variable, the free-floating non-native macrophyte, Pontederia (=Eichhornia) crassipes recorded the highest assimilation potential of heavy metals in water (e.g., Fe and Cu) and sediments (e.g., Fe and Zn), followed by a submerged native macrophyte, Stuckenia pectinatus, and three native emergent species, Typha capensis, Cyperus sexangularis, and Phragmites australis. Pollution indices clearly showed the promising assimilation by native and non-native macrophytes species; however, the Swartkops River was heavily influenced by multiple non-point sources along the system, compromising the assimilation effect. Furthermore, we emphasise that excessive anthropogenic inputs compromise the system's ability to assimilate heavy metals inputs leading to water quality deterioration. [ABSTRACT FROM AUTHOR]

Understanding the relationships among perceptions, behaviors and awareness of environmental initiatives is important for both policy makers and social scientists. There is, however, limited consensus among scholars as to the reasons for differences and similarities among ethnic and socio-economic groups in their environmentally related attitudes and behaviors. South Africa, which has established a constitutional right to a safe environment, together with the presence of parallel first and third world populations, offers an unusual setting in which to examine these issues. Using the 2004 South African General Household Survey, the similarities and differences between African and non-African households with respect to the perceptions, behaviors and awareness of programs related to water and water pollution are examined. Africans and those with lower socio-economic status are more likely to perceive water pollution as a community problem; educational attainment is unrelated to this perception. In combination with perception of water pollution as a problem, education is positively related to taking action to treat water for drinking and food preparation. Awareness of a highly touted program to clear waterways of alien vegetation is strongly positively related to socio-economic status, and is much more common among non-Africans than Africans. [ABSTRACT FROM AUTHOR]

The legacy of the inequitable water policy under apartheid continues to impact water services in economically less developed and rural areas in South Africa. Previous studies typically examine this relationship either by using aggregated data at the national level for large-scale research or by using data collected at the provincial or municipal level only for a specific locality. This study attempts to perform nationwide analysis using fine-scale data to give a spatial representation of the efficacy of water policies in South Africa. We used satellite night-time light data as a proxy of economic development and surface water quality at a quaternary water area level to investigate any income or racial inequality regarding water pollution, controlling for the spatial dependency of the observations. We found a spatial discrepancy in the relationship between water quality and economic development: economic development improves water quality in western provinces and in former white-dominated areas, whereas it generally degrades water quality in other regions of the country. These results suggest the inability of the government to equitably provide the same standards of water policies nationwide and the presence of inequitable policies as legacies of apartheid at the lowest level of water policy implementation. [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]