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MSc (Environmental Management with Ecological Water Requirements), North-West University, Potchefstroom Campus Due to the increasing presence of platinum (Pt) in the environment, it becomes crucial to identify its toxic potential in species at risk of being exposed, especially those found in aquatic environments where metal pollutants tend to accumulate. Comprehensive characterisation of possible adverse effects of Pt exposure on aquatic organisms remains vague. To accurately determine the impact on the aquatic environment, the compartmentalisation of Pt in the aquatic environment needs to be understood. However, the various environmental influencing factors and the binding characteristics of PGEs identified in recent studies concluded that laboratory studies (controlled environment) alone do not provide sufficient information concerning the behaviour of PGEs in the aquatic environment. As a result of the various environmental influencing factors, field-based studies cannot provide laboratory “controlled” information on the behaviour of PGEs as it can be tough to correlate field-based results to that of laboratory studies. Therefore, it is crucial to address the void between these two scientific approaches in the PGE study area and broaden our knowledge on the effects of Pt in the aquatic ecosystem. Using 18 microcosms, mimicked natural aquatic communities were established. These communities were then exposed to a range of standard Pt concentrations (0.1, 1,10,100, and 500 μgPt/L) for eight weeks. Samples were collected on three separate occasions: 48 hours (acute), four weeks (chronic), and eight weeks (chronic). These samples were then analysed to determine the compartmentalisation of Pt in the aquatic environment. Platinum concentrations in the different aquatic compartments (water, sediment, macrophytes, and artificial mussels) were quantified using an Atomic Absorption Spectrometer (AAS) and an Inductively Coupled Plasma-Mass Spectrometer (ICP-MS) to determine the different Pt concentrations within each of the compartments. The separate compartments were divided into bioavailable environmental accumulation (water and sediment) and bioaccumulation (macrophytes and artificial mussels). Platinum concentrations in the water column decreased over time. Similarly, the sediment, macrophytes and, artificial mussels (AM) showed higher initial accumulated Pt followed by a progressive decrease over time. Two macrophyte species were identified (Fontinalis antipytetica and Charophyta sp) and both species accumulated Pt over time. Interestingly, the accumulation levels between the two species varied, where the F. antipytetica reported a higher accumulation level than the Charophyta sp. The difference in accumulation can be explained by the different habitat preferences of the species in the ecosystem, and their differences in Pt absorption and metabolism since macrophyte species rooted in the sediment are known to be more sensitive to metal pollution than suspended macrophytes (Gupta et al., 2013). Epiphytic and benthic diatom community assemblages were sampled 48-hours (acute) and eight weeks (chronic) after exposure to assess the impact of different Pt exposures on diatom community assemblages. Initial observations reported that diatom communities showed little to no response after the 48-hours; however, all the samples collected from the aquatic habitat indicated the presence of pollution tolerant taxa after a chronic eight-week Pt exposure. Diatom deformities were also observed, although these deformities occurred at Pt levels higher than those present in the environment. A total of 25 type 1 (morphological abnormalities of the frustule) teratologies were identified from four 500 μgPt/L chronic exposure samples. Resulting in 1.025% of teratologies identified for the epiphytic diatom community and 1.875% of teratologies for the benthic diatom community. This teratology indicates a possible disruptive potential of increased Pt concentrations on aquatic communities. Masters

MSc (Environmental Management with Ecological Water Requirements), North-West University, Potchefstroom Campus The water quality of the Crocodile-West River is deteriorating and has affected the ability of the water resource to be utilised adequately. Mining, urban, and agricultural run-off have negatively impacted the water quality of the Crocodile-West River catchment and has caused water quality issues in the catchment. The Crocodile-West River is monitored by the Department of Water and Sanitation where complex water quality data are collected and stored in the water quality database called the Water Management System (WMS). The Canadian Council of Ministers of the Environment Water Quality Index (CCME WQI) was applied in the study to evaluate surface water quality data to protect aquatic ecosystems. In this study, the CCME WQI integrated physico-chemical variables collected in the Crocodile-West River to determine its applicability as an assessment tool for Department of Water and Sanitation (DWS) managers in evaluating the health of the catchment for decision-making purposes. The water quality data was sourced from the Water Management System. The water quality data consisted of annual seasonal data of DWS monitoring sites 90194, 90167, 90203, 90204 and 90233 on the Crocodile-West River from 1976 to 2018. The water quality variables chosen in the study were ammonia (NH3), nitrate/nitrite (NO3-/NO2-), phosphate (PO43-), calcium (Ca2+), magnesium (Mg2+), potassium (K+), chloride (Cl-), electrical conductivity (EC), sulphate (SO42-) and pH. Each data set was organised into average seasonal data for summer, autumn, winter and spring. This was done for each water quality variable per year for each site. The average seasonal data for each water quality variable was organised into a series of data from 1976 to 2018. The seasonal data was used to calculate the CCME WQI values and plot PCA biplots for each site from 1976 to 2018. A box-and whisker graph was plotted to determine the spatial differences in the WQIs of each site. A principal component analysis (PCA) was used to evaluate the success of the CCME WQI as an appropriate tool to evaluate water quality data of the Crocodile-West River. The overall status of the Crocodile-West River was good in the 1990s and early 2000s and deteriorated to marginal quality from 2010 to 2018. The CCME WQI was able to indicate the temporal and spatial water quality changes of the Crocodile-West River from 1976 to 2018. The trend in CCME WQI of sites situated upstream of Crocodile-West River deteriorated more than CCME WQI trends for sites situated downstream. The CCME WQI is sensitive to the changes in number (F1) and magnitude (F3) of water quality variables that exceeded the target water quality guidelines of the study. The years which have lower F1 scores and F3 scores have the highest CCME WQI scores than the years which have higher F1 scores and F3 scores. The PCA results have indicated that the spatial distribution of the sites can influence the pollutants surveyed. The CCME WQI correlated with PCA biplot in flagging pH, PO43- and NH3 as problematic water variables that negatively impacted the water quality of each site for the period of 1976 to 2018. In addition, the PCA biplot showed that the contribution of pH, PO43- and NH3 to the pollution of each site was insignificant as compared to NO3-/NO2-, Cl- and SO42- other water quality variables in the study. The CCME WQI and PCA were implemented successfully in the Crocodile-West River. CCME WQI was flexible in integrating the water quality data and the water quality guidelines sourced from different water quality guidelines to interpret the overall water quality status of the Crocodile-West River. The CCME WQI can be enhanced by incorporating scientific and local knowledge of the river to ensure that the correct water quality variables appropriate with Crocodile-West River are included in the calculation of CCME WQI of the Crocodile-West River. Masters

MSc (Environmental Management with Ecological Water Requirements), North-West University, Potchefstroom Campus Anthropogenic activities are important for various purposes such as economic activities, recreation and to partially safeguard food and energy across the world. In a semi-arid country such as South Africa, where the freshwater resources are already vulnerable and threatened by drought and deteriorating water quality, the catchment conditions are a major concern contributing to ecological status decline. The potential impact on fish species and habitat associated with anthropogenic activities that change catchment conditions are extensive and devastating. Therefore, the aim of this study was to assess the fish and habitat integrity representing the ecological status of the Mooi River located in the North-West Province. The fish species were assessed during austral spring in October 2018 together with the habitat integrity. The Fish Response Assessment Index and Index of Habitat Integrity (IHI) were used to determine Present Ecological State (PES) and habitat indicators linked to fish species. A Principal Component Analysis (PCA) and unconstrained ordination were used to determine the temporal and spatial variation of landscape and soil properties for fish species. The results showed that there is an abundance of anthropogenic activities which change catchment conditions and the in-channel and bank conditions are modified. The in-stream and riparian zone integrity scores were between 40-59% and 60-79% placing it to category D or C/D. The results for overall fish PES were 52, placing it in category D, therefore, largely modified. The results of the habitat integrity and PES are within the recommended limit of Resource Quality Objectives (RQOs). The results of the PCA and unconstrained ordination indicated temporal variation at Sites 2 and 3 as well as sites 4, 5 and 6 which were grouped together. Site 1 varied spatially and grouped separately due to increased changes in landscape. The PES across all sampling sites is moderately to largely modified, therefore there is a great need to continuously monitor the catchment and alert community and stakeholders on possible activities that may trigger a critical modified environment. Masters

The Phongolo River Floodplain (PRF) is South Africa's largest floodplain, unique in being the only large floodplain able to sustain permanent waters throughout the dry season (Kyle, 2002). This highly productive region contains around 90 floodplain associated pans which are rich in biodiversity and is known to be of high ecological and socio-economic importance (Dube et al., 2017). The floodplain is surrounded by informal settlements and rural communities which are reliant on these aquatic resources, not only for domestic use or agricultural purposes such as watering livestock and subsistence farming, but also for subsistence fisheries as a source of protein (Coetzee et al., 2015). A recent study by Coetzee et al. (2015) indicated that several fish species in the study area are important sources of protein within artisanal fishery practices. Contamination due to the introduction of pesticides into aquatic ecosystems is of great concern, as many banned (World Health Organisation (WHO, 2002)) organochlorine pesticides (OCPs) are persistent in the environment and this is reflected by the fact that although many OCPs are no longer used, they still remain present in many, if not all aquatic ecosystems (Gerber et al., 2016). Implementation of effective long term management plans rely directly on fully understanding chemical compounds as well as their risks to both ecosystems and humans, where these aspects can be assessed using; (1) stable isotopes and trophic magnification factors (TMF's) and (2) human health risk assessments via exposure through consumption (Verhaert et al., 2013, Verhaert et al., 2017).

South Africa is one of six global fish invasion hotspots and as a result, non-native fishes are common components of the fish assemblages in all of the major river systems. The rate of establishment for introduced fish into South African rivers is high (79%) and the vector responsible for the highest establishment rate is interbasin transfer schemes with 80%. Introductions of non-native fish into river systems can negatively affect native fish species through hybridisation, competition for food sources and predation, and the introduction of associated parasites and diseases. The aims of the current study were to provide evidence of the introduction of Labeo capensis into the Crocodile River (West) system, using morphological and molecular techniques, and to record the fish health and gonadosomatic index to determine the invasive status of L. capensis. From the fish health assessment index and gonadosomatic index of L. capensis collected from Olifantsnek Dam, it can be concluded that L. capensis is a healthy reproducing population. Because this fish species can survive and reproduce in newly colonised river systems, it has the potential to compete with the native fish species for food and habitat, but can also hybridise with native Labeo species. Keywords: fish health, genetic barcode, gonadosomatic index, invasion hotspots, translocation

Freshwater biodiversity is under constant threat from a range of anthropogenic stressors. Using South Africa’s Phongolo River and floodplain (PRF) as a study case, the aim of this chapter is to provide an overview of the conservation and management of freshwater biodiversity in a highly diverse subtropical ecosystem. The PRF is the largest floodplain system in South Africa which is severely threatened by irregularly controlled flood releases from a large upstream dam, prolonged drought, deteriorating water quality, organic pollutants and the increasing dependence of the local communities. Based on a decade of survey of the PRF conducted from 2010 to 2020, this chapter highlights the current diversity of aquatic organisms (invertebrates, fishes, frogs and their parasitic fauna), followed by an overview of their biological and physical stressors. The current challenges in the management of the aquatic biodiversity of this region and a way forward to conservation strategies are also addressed in this chapter.