Paul Johan Oberholster

University of the Free State | ufs · Center for Environmental Management

The incessant dumping of solid waste has been an issue of global attention, causing significant risks to the environment and human health. The biodegradable organic components of the waste materials pose a greater opportunity in the production of beneficial products. Therefore, adequate management of organic solid waste is key to mitigate environme...

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 po...

Poorly treated domestic wastewater and diffuse nutrient loading from agriculture and informal human settlements greatly threaten water resources due to the alteration of ecosystem function and the reduction of the water’s fitness for use. Thus, the aim of the study was to assess nutrient loading in the eutrophic Roodeplaat Dam (RD) to inform water...

The rapid and improper disposal of electronic waste (e-waste) has become an issue of great concern, resulting in serious threats to the environment and public health. In addition, e-waste is heterogenous in nature, consisting of a variety of valuable metals in large quantities, hence the need for the development of a promising technology to amelior...

The direction, growth, integration, management, and understanding of coupled human and natural systems of urban areas will significantly impact humanity and determine whether the earth can have a more sustainable future. Additionally, the social, environmental, and economic systems in urban areas are further impacted by climate change, leading to d...

A proposed urban biosphere reserve model concept for the City of Tshwane as a bio-intelligent approach to mitigate climate change

Floating treatment wetlands are a variation of constructed wetland treatment systems that can be applied effectively in habitat conservation and biodiversity and rewilding programmes, community sustainability, water treatment and purification, and mitigating pollution. Specific critical criteria can influence the success of floating treatment we...

The presence of potentially toxic elements (PTEs) in soil and plants is a risk factor to human well-being and the environment. Soil and leaves from a traditional medicinal plant, Vachellia karroo, known as the sweet thorn plant, were assessed to determine the extent of pollution by PTEs from gold mine tailings in a case study area of Matjhabeng Loc...

Unlabelled: Wastewater stabilization ponds (WSPs) rely on the metabolic activities of the inhabiting microbiota to treat wastewater. A selected consortium of Chlorella vulgaris and Chlorella protothecoides were used to manipulate the natural resident microalgae assemblage to improve the treatment performance of a domestic wastewater pond treatment...

This study employed different indices, namely the weighted arithmetic water quality index (WQI), Carlson Trophic State Index (TSI), van Ginkel TSI, and Trophic Level Index (TLI) to determine the water quality status of a man-made dam for the needs of sustainable water resource management in Southern Africa. The selection of indices for the study wa...

Design considerations of floating treatment wetland systems

Accessing the status of clean drinking water, sanitation, and hygiene remains a challenge in sub-Saharan Africa (SSA). The current article contributes to the progress made by the WASH initiatives in ten SSA countries in eliminating open defecation by 2030, using theoretical data from 2017 to 2019. The authors used regression trend estimation to obs...

Groundwater contribution towards human health and livelihood depends on the contaminants level in groundwater. Many people in rural communities are being exposed to waterborne diseases resulting from drinking untreated contaminated groundwater. This study argues that the lack of implementation of available groundwater remediation methods and associ...

The present study aimed to employ different modified indices (Canadian Council of Ministers of the Environment (CCME) water quality index (WQI) and comprehensive pollution index (CPI)) to determine the water quality status of the Swakoppoort and Von Bach dams based on physicochemical and biological parameters. The data generated shows that the CCME...

Acid mine drainage (AMD) is a global problem with severe consequences for the environment. South Africa’s abandoned mines are a legacy from the country’s economic dependence on the mining sector, with consequent negative impacts on ecosystems. AMD remediation includes active and passive techniques. Constructed wetlands (a passive technique) have lo...

The search for effective and sustainable techniques for the decontamination of polluted water bodies has led to significant progress over the last two decades with the emergence of the concept of bioremediation, i.e., the use of naturebased solutions (NBSs) to eliminate pollution. The sustainability of these processes is based on the availability o...

The Grootspruit valley bottom wetland in South Africa, due to the impact of acid mine drainage (AMD) from an abandoned coal mine, was severely degraded before ecologically engineered interventions, as a passive treatment process, in 2014. The surface water flow of the wetland was redirected using concrete structures to enlarge the surface area of t...

Toxic phytoplankton in the aquatic ecosystems are dynamic, affecting water quality. It remains unclear as to how possible toxic phytoplankton assemblages vary vertically and temporally in Swakoppoort and Von Bach dams, located in a dry subtropical desert region in central Namibia. The following variables were analyzed: pH, Secchi depths, turbidity,...

Rapid commercialisation of nano-enabled products (NEPs) elevates the potential environmental release of engineered nanomaterials (ENMs) along the product life cycle. The current review examined the state of the art literature on aquatic environment exposure and ecotoxicity of product released (PR) engineered nanomaterials (PR–ENMs). Additionally, t...

The reuse of wastewater has been observed as a viable option to cope with increasing water stress in Africa. The present case studies evaluated the optimization of the process of phycoremediation as an alternative low-cost green treatment technology in two municipality wastewater treatment pond systems that make up the largest number of domestic se...

Globally, increased stress on water resources and associated ecosystems is reported. Reducing overdependence on a single water resource grows, with growing global interest on hydrological cycle interactions, impacts of land uses and impacts of these interactions on dependant ecosystems. Through a case study, groundwater exchanges between wetlands a...

The Olifants River catchment has been adversely affected by anthropogenic land-use activities over the last decade. This study aims to determine the variation in surface and groundwater concerning heavy metal pollution. The collection of surface and groundwater was performed at three different land-use locations; namely, wastewater treatment works...

Ecological restorations of reservoirs are implemented worldwide; however, minimal successes are reported and understood for warmer African lakes like Swakoppoort Dam, Namibia. The objectives of the study were (a) to establish the effectiveness of the two control measures in reducing cyanobacteria growths in comparison with untreated control areas a...

The iron and steel industry is a major global industry that consumes vast quantities of energy and causes environmental degradation through greenhouse gas emissions and industrial waste generation, treatment, and disposal. There is a need to manage complex iron and steel industrial waste in Africa, which requires a system engineering approach to ze...

The study aimed to investigate the waste characteristics and management activities in the iron and steel industry in Southern Africa based on a case study in South Africa. A four-phased decision-support framework (DSF) has been suggested to approach industrial waste management in Southern Africa’s iron and steel industry, consisting of a desktop-ba...

Currently water resources in nature conservation areas are under severe pressure due to external drivers of anthropogenic pollution. There is a lack of monitoring tools to determine water quality status of dams situated in nature reserves receiving a mixture of pollutants over space and time. The present study was conducted over a 12-month period w...

With the potentially fatal effect of COVID-19 and its devastating impact on economies worldwide, some environmental scientist has suggested the use of waste from household sewage to trace the movement of SARS-CoV-2, within a given country. However, this approach is not without challenges where developing countries lack proper and adequate hygiene a...

The Value Stream Mapping (VSM) method was applied to a case study in the iron and steel industry in Southern Africa as a supporting management tool to identify, demonstrate, and evaluate industrial waste and comprised of three steps. The first step included collecting and verifying waste generation and flow data as the VSM data input step. The seco...

The Olifants River in South Africa, is well known to be one of the most polluted rivers in Southern Africa. Water quality issues in the River Catchment are known catchment are known to be primary related to salinity, eutrophication and acid mine drainage. This study aimed to assess the efficiency removal of metal ions in effluent wastewater from a...

Metal(loid) pollution in aquatic ecosystems has become a cause for concern, particularly in areas where communities depend on services from these systems for their livelihood. This dataset presents the metal(loi) concentrations recorded in the water column, bottom sediment, and tissues of Oreochromis mossambicus and Labeo rosae from Flag Boshielo D...

International scientific partnerships are key to the success of strategic investments in plant science research and the farm-level adoption of new varieties and technologies, as well as the coherence of agricultural policies across borders to address global challenges. Such partnerships result not only in a greater impact of published research enha...

Wastewater stabilization ponds (WSP) are a common method to treat wastewater before release. The purpose of the current study was to find the most inexpensive coagulation and flocculation reagents to use during harvesting of WSP algae from effluent so that water without algae can be generated for irrigation purposes. In the study, the toxicity of e...

Effluent from abattoir industries containing metals ions is known to adversely affect the quality fresh water. Water pollution is a global concern and its effects are difficult to reverse. This study evaluates the efficiency of the use of the shrimp chitosan cross-linked with glutaraldehyde as an adsorbent for the removal of cations in poultry and...

The response of biological indicators with ecosystem food web and agricultural relevance were examined in biologically treated cyanobacteria culture water. To assess bioindicator responses to variations in the toxicity measurements, a case study on the filtrate of treated cyanobacteria was conducted. Cyanobacterial cultures of dominant Oscillatoria...

In the meat production industry, large volumes of wastewater are generated containing great quantities of organic matter that requires y safe disposal or utilization. As a result, management of poultry wastewater is of great concern worldwide. However, problems associated with wastewater disposal are a well-known phenomenon. Nevertheless finding so...

The Loskop Dam in South Africa is the most contaminated waterbody in the Olifants River which is a transboundary river that flows into Mozambique. The present study measured selected metal concentrations in the muscle of Labeo rosae and Oreochromis mossambicus from Loskop Dam, and assessed the human health risks associated with consumption of these...

The presence of heavy metals such as chromium within water sources are considered as one of the most vital problem to the environment. Accumulating of chromium within the human body, can cause various diseases and disorders. Chitosan cross-linked glutaraldehyde adsorbent (formed from the acetyl group of chitin from alkaline solution) is widely a we...

The success and long term effectiveness of extensive and expensive engineering solutions to restore streams impacted by Acid Mine Drainage (AMD) is rarely tested. Concentrations of pollutants were measured in water along a longitudinal gradient from a stretch of the Tweelopie stream, South Africa, that receives pH-treated acid mine drainage (AMD) f...

Biological control of cyanobacteria is a viable means of controlling nuisance bloom occurrences; however the majority of studies done are against Microcystis sp., with a commonly lytic effect caused. Filamentous cyanobacteria such as Oscillatoria are not as extensively studied in this area of biological control and are often part of Microcystis dom...

The eutrophication of waterways has become an endemic global problem. Nutrient enrichment from agriculture activities and waste water treatment plants are major drivers, but it remains unclear how lowland sandy rivers respond to eutrophication. The objective of this study was the development and verification of eutrophication index for sandy rivers...

Employing specific algae treatment to treat municipal domestic wastewater effluent presents an alternative practice to improving water quality effluent of existing rural pond systems in Southern Africa. In the present study, domestic wastewater was treated by using existing infrastructure and inoculated specific selected algae strains in a pond sys...

Freshwater resources in semi-arid countries are under constant threat from pollution. One of the major pollutants is acid mine drainage (AMD), which not only lowers the pH of the water, but contains high sulphuric acid and high metal concentrations. Bacteria and algae are the first organisms to respond to stressors such as reduced pH and high metal...

Biological control of cyanobacteria is a well-researched area with a central focus on laboratory-scale studies. Numerous reports have been made on algicidal isolates, with bacteria as a major component of the antagonists. The research in this review draws a brief summary of what is currently known in the area of freshwater cyanobacteria being inhib...

Coal mining has the potential to affect and disturb water ecosystems throughout the life cycle of a mining operation, by point and nonpoint source pollution. Impacts of direct water pollution can result from any activities that involve direct discharges into waterbodies e.g., riverine tailings or tailing impoundment releases or acid mine drainage (...

The regulation of anthropogenic pollution inputs into large rivers is an important aspect of ecological resilience of aquatic systems and river pollution management. The current study examined the relationship between contamination loads, hydrological and morphological patterns and the distribution of macroinvertebrates and epipelic diatoms in the...

The presence of harmful algal blooms (HABs) and cyanotoxins in drinking water sources poses a great threat to human health. The current study employed molecular techniques to determine the occurrence of non-toxic and toxic cyanobacteria species in the Limpopo River basin based on the phylogenetic analysis of the 16S rRNA gene. Bottom sediment sampl...

Globally, the dependence of river systems to delayed discharge of subsurface water to augment flows during dry seasons is well documented. Discharge of fresh subsurface water can dilute concentrated river flow quality during reduced flow. Observed and reported results on the Berg River’s declining water quantity and quality are a concern to the reg...

The presence of harmful algal blooms (HABs) and cyanotoxins in drinking water sources poses a great threat to human health. The current study employed molecular techniques to determine the occurrence of non-toxic and toxic cyanobacteria species in the Limpopo River basin based on the phylogenetic analyses of 16S rRNA gene. The bottom sediments samp...

The assessment of ecological integrity of river systems is multidisciplinary and necessary for effective river management. The objectives of this study were (i) to characterize the spatial and temporal distribution of macroinvertebrate and algae community assemblages; (ii) to determine the environmental variables that affect assemblage distribution...

Filamentous algae biomass is very limited in aerobic constructed wetlands and totally absent in anaerobic constructed wetlands. Its contribution to the removal of sulphur from acid mine drainage will therefore rarely reach a significant level if not used in association with secondary algae treatment ponds as part of a biological hybrid treatment sy...

Before the introduction of reclamation legislation in South Africa, final cut lakes in mining areas were left without any restoration while the final excavation was not back filled. Characteristics of these lacustrine water bodies vary considerably, but they are often linear in shape, large (1-30 ha), deep (2-30 m) and have poorly developed littora...

Rising environmental pressures on water resources and resource quality associated with urbanisation, industrialisation, mining and agriculture are a global concern. In the current study the upper Olifants River catchment as case study was used, to show that acid mine drainage (AMD) and acid precipitation were the two most important drivers of possi...

Acid mine drainage (AMD) from coal mining in the Mpumalanga Highveld region of South Africa has caused severe chemical and biological degradation of aquatic habitats, specifically depressional wetlands, as mines use these wetlands for storage of AMD. Diatom-based multimetric indices (MMIs) to assess wetland condition have mostly been developed to a...

Information on the response of temporary depressional wetland diatoms to human-induced disturbances is a limited and important component for the development of temporary wetland biological assessments in human-modified landscapes. Establishing a reference condition of variation due to natural disturbances in depressional wetlands using diatoms is n...

Thyroid function and nutritional indicators were measured in obese, steatitis-affected Mozambique tilapia Oreochromis mossambicus from Loskop Reservoir (LR), South Africa. Plasma thyroid hormones (especially T3) and thyroid follicle histomorphology revealed high levels of activity in every aspect of the thyroid cascade measured in fish from LR comp...

Functional-based assessments to identify the effects of human-induced disturbances on diatom communities are increasingly used. However, information on the response of functional groups to natural disturbances in temporary depressional wetlands is limited although important for the development of temporary wetland biological assessments. We assesse...

The alien invasive silver carp Hypophthalmichthys molitrix established a self-sustaining feral population in an oligotrophic impoundment, Flag Boshielo Dam, in South Africa. The ability of this population to persist in a dam with low algal biomass (median annual suspended chlorophyll a = 0.08 µg l⁻¹), and limited access to rivers considered large e...

Interdisciplinary research in the fields of ecohydrology and ecogeomorphology is becoming increasingly important as a way to understand how biological and physical processes interact with each other in river systems. The objectives of the current study were 1) to determine changes in invertebrate community due to hydrological stages, 2) to link loc...

Over the past decade, several clustered, multispecies, wildlife mortality events occurred in the vicinity of two man-made earthen dams in the southern and south central regions of the Kruger National Park, South Africa. On field investigation, heavy cyanobacterial blooms were visible in these impoundments and analysis of water samples showed the do...