Articles

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Open Access
Flood Frequency Analysis of Annual Maximum Stream Flows for Luvuvhu River Catchment, Limpopo Province, South Africa
(2012) Singo, L. R.; Kundu, P. M.; Odiyo, J. O.; Mathivha, F. I.; Nkuna, T. R.
Luvuvhu River Catchment (LRC) is one of the regions in South Africa where floods have caused enormous damage and impacted negatively on fauna and flora. Over the years, the catchment has experienced floods resulting from heavy rainfall associated with the ITCZ. Annual maximum flow data from 8 stations with 50 years hydrological data were used to analyze flood frequencies in the catchment. To derive the probability of occurrence of flood events, the frequency distributions which could best describe the past characteristics and magnitudes of such floods were tested. This involved the determination of the best flood frequency models, which could be fitted to the available historical recorded data. The distribution models used included the Generalized Extreme Value, Gumbel or Extreme Value type 1, Log-Normal and the Log Pearson type III distributions. The extreme value analysis showed that the Gumbel and Log Pearson type III distributions provided the best fit.
Open Access
An evaluation of the effects of climate change on flood frequency in the Luvuvhu River Catchment, Limpopo Province, South Africa
(WIT Press, 2014) Kundu, P. M.; Singo, R. L.; Odiyo, J. O.; Nkuna, R. N.
Climate change poses a great risk to natural resources and agriculture in the Luvuvhu River Catchment. The catchment has experienced floods resulting from higher than normal rainfall associated with the Intertropical Convergence Zone and cyclones, which have caused enormous damage to property and impacted negatively on fauna and flora and human livelihoods. In order to understand the dynamics involved in the effects of climate change in the catchment, annual maximum flow data was used to evaluate flood frequencies. The distribution models used in the study included the Generalized Extreme Value distributions, the Gumbel Extreme Value type I distribution, the Log-normal distribution and the Log Pearson type III distribution. The extreme value analysis showed that the Log-normal and Log-Pearson type III distributions provided the best fit, which could be used to derive the probability of occurrence of flood events. The results showed a general increase in the frequency of extreme events, accompanied by floods of higher magnitude.
Open Access
Assessment of As and Hg in mine tailings and indigenous grass : a case study of non-functional New Union Gold Mine, South Africa
(2015) Mundalamo, Tsedzuluso; Gumbo, Jabulani R.; Muzerengi, Confidence; Dacosta, Francis
The present study was carried out to assess the uptake of toxic metals, arsenic (As) and mercury (Hg), by Cynodon dactylon grass species at New Union gold mine tailings, Limpopo Province, South Africa. The samples were collected from New Union Gold Mine tailings and from Ka-Madonsi Village (control), and concentrations of As and Hg in soil and plant material were determined by ICP-MS. The average dry weight concentrations of As and Hg in mine tailing dam A were 2.53 and 1.18 µg/g, respectively, and 2.24 and 0.91 µg/g, respectively, in mine tailings B. The average dry weight of As and Hg in the control soil samples were 0.30 and 0.05 µg/g, respectively. The C. dactylon, on average dry weight, absorbed 5.45 µg/g of As, and 1.72 µg/g of Hg from mine tailings A, and 4.29 µg/g of As; and 1.55 µg/g of Hg from mine tailings B. The control grass, on average dry weight, absorbed 0.53 µg/g and 0.01 µg/g of As and Hg, respectively. In most cases, significant differences were observed between bioaccumulation of Hg and As in plant tissue from mine sites and control sites. The study showed that the bioconcentration factor was less than 1 for the acidic mine tailings, with exception of the root and rhizome system which was greater than 1. This contrasted sharply with the control site where the pH was alkaline, and As and Hg levels were low. The pH values were significantly different (p <0.05) between the soils originating from mine tailings and the control site. The electrical conductivity (EC) of soil at mine tailings A and B were 1847.35 and 1777.5 µS/cm, respectively. The EC for the control site was significantly different (p < 0.05) at 543.3 µS/cm. C. dactylon was found to be capable of bioaccumulation of As and Hg, effective at soil stabilization, and grew well under the acidic conditions. The control grass was healthy and thrived under the alkaline conditions.
Open Access
Willingness to pay for water services in two communities of Mutale Local Municipality, South Africa : a case study
(2015) Rananga, H. T.; Gumbo, Jabulani R.
The provision of reliable and adequate drinking water services in rural communities is important. Here, the researchers reported on a study that evaluated the respondents’ willingness to pay for water services in the two communities in Mutale Local Municipality, South Africa. The study was accomplished through open-ended questionnaire interviews with selected respondents. The study showed that respondents were dissatisfied with the unreliable water services (89.9%) but were willing to pay for water services to secure reliable water services (95.5%). The respondents with tertiary level education were willing to pay R 150 per month per 6 kilolitres. The maximum 6 kilolitres is the free basic water services that the municipality can provide without collecting water revenues. The following variables: literacy levels; household size of 3 to 6 members; the age of 40; and monthly incomes, had a significant effect (p = 0.005) on the monetary amount and the willingness to pa
Open Access
An evaluation of the performance of tourism at Mapungubwe National Park, South Africa
(2015) Sinthumule, Ndidzulafhi I.
Mapungubwe National Park is one of the parks that were created to conserve both biodiversity and cultural heritage in South Africa. It has also been awarded the status of a World Heritage Site by the United Nations Educational, Scientific and Cultural Organization (UNESCO). This study evaluates the performance of tourism at the park and the cultural landscape. Data on visitations and lodging occupancy after the Park was declared as a World Heritage Site were examined. In order to understand possible causes of tourism trends, visitation data was supplemented by social survey data. The study established that there is no sharp increase on the tourist numbers to the Park. In addition, bed occupancy is below 50% since the Park was declared a World Heritage Site. Potential barriers contributing to low bed occupancy are discussed. The study concludes that the World Heritage Site status did not trigger an increase in tourism in Mapungubwe National Park. Contributing factor is newness of Mapungubwe as a national park in South Africa.
Open Access
Defluoridation of groundwater using diatomaceous earth : optimization of adsorption conditions, kinetics and leached metals risk assessment
(Taylor and Francis, 2015-08-27) Izuagie, Anthony A.; Gitari, Wilson M.; Gumbo, Jabulani R.
In Sub-Saharan Africa, many rural communities depend on boreholes as the most appropriate source of water supply. Sadly, water from some of the boreholes contains ﬂuoride above the WHO guideline of 1.5 mg/L. Hence, deﬂuoridation is necessary. The aim of this study is to investigate the ﬂuoride uptake capacity of diatomaceous earth (DE), a natural resource at optimized conditions by batch method. X-ray ﬂuorescence analysis showed that the major component is silica (83.1%), while Al2O3 is the main minor component. XRD shows it is an amorphous material. For 8 mg/L ﬂuoride spiked water, the highest per cent ﬂuoride removal at optimum adsorption conditions (contact time: 30 min, adsorbent dosage: 8 g/L, pH 2, temperature: 298 K and shaking speed: 200 rpm) was between 23.4 and 25.6%. PO3 4 in tested ﬁeld water was observed to reduce the ﬂuoride uptake capacity of ﬂuoride. The sorption data ﬁtted better into Freundlich isotherm than Langmuir isotherm. Fluoride sorption process was found to be a second-order kinetic. Inductively coupled plasma-mass spectrometer analysis of treated water revealed that metal and non-metal species were released at trace levels. Modiﬁcation of DE would be necessary to enhance the ﬂuoride adsorption capacity
Open Access
Impact of land use change on surface runoff and stream discharges in Luvuvhu River Catchment
(2016) Singo, L. R.; Kundu, P. M.; Odiyo, J. O.
Luvuvhu River catchment in Limpopo Province of South Africa experiences floods resulting from heavy rainfall of intensities exceeding 15 mm per hour associated with the Intertropical Convergence Zone. The generation of runoff is triggered by the rainfall intensity and soil moisture status. Runoff was calculated as a product of the net precipitation and a curve number coefficient. It was then routed using the Muskingum-Cunge method through the basin along flow paths determined by the topography using a diffusive wave transfer model that enabled the calculation of response functions between start and end point, depending upon slope, flow velocity and dissipation characteristics along the flow lines. Results showed that the simulated discharges closely compared with the measured discharges without the need for model optimization. It was concluded that simulation techniques had the potential to determine the influence of changes in land use to the hydrologic response of the catchment.
Open Access
Synthesis and performance evaluation of AI/Fe oxide coated diatomaceous in groundwater defluoridation : towards fluoris mitigation
(Taylor and Francis, 2016-05-24) Izuagie, Anthony A.; Gitari, Wilson M.; Gumbo, Jabulani R.
The quest to reduce ﬂuoride in groundwater to WHO acceptable limit of 1.5 mg/L to prevent diseases such as teeth mottling and skeletal ﬂuorosis was the motivation for this study. Al/Fe oxide-modiﬁed diatomaceous earth was prepared and its deﬂuoridation potential evaluated by batch method. The sorbent with pHpzc 6.0 § 0.2 is very reactive. The maximum 82.3% ﬂuoride removal attained in 50 min using a dosage of 0.3 g/100 mL in 10 mg/L ﬂuoride was almost attained within 5 min contact time; 81.3% being the percent ﬂuoride removal at 5 min contact time. The sorbent has a usage advantage of not requiring solution pH adjustment before it can exhibit its ﬂuoride removal potential. A substantial amount of ﬂuoride (93.1%) was removed from solution when a sorbent dosage of 0.6 g/100 mL was contacted with 10 mg/L ﬂuoride solution for 50 min at a mixing rate of 200 rpm. The optimum adsorption capacity of the adsorbent was 7.633 mg/g using a solution containing initially 100 mg/L ﬂuoride. The equilibrium pH of the suspensions ranged between 6.77 and 8.26 for 10 and 100 mg/L ﬂuoride solutions respectively. Contacting the sorbent at a dosage of 0.6 g/100 mL with ﬁeld water containing 5.53 mg/L at 200 rpm for 50 min reduced the ﬂuoride content to 0.928 mg/L—a value below the upper limit of WHO guideline of 1.5 mg/L ﬂuoride in drinking water. The sorption data ﬁtted to both Langmuir and Freundlich isotherms but better with the former. The sorption data obeyed only the pseudo-second-order kinetic, which implies that ﬂuoride was chemisorbed
Open Access
Impact on water quality of Nandoni Water Reservoir Downstream of municipal sewage plants in Vhembe District, South Africa
(2016-06-24) Gumbo, Jabulani R.; Dzaga, Ratshilumela Aaron; Nethengwe, Nthaduleni Samuel
Open Access
Spatial variation of reference evapotranspiration and its influence on the hydrology of Luvuvhu River Catchment
(2016-07) Singo, L. R.; Kundu, P. M.; Mathivha, F. I.
This study estimated spatial variation of reference evapotranspiration (ETo) and its influence on the hydrology of Luvuvhu River Catchment.The ETo plays a key role in irrigation systems design, water resource management under irrigated and rainfed production.Simulation of ETo was performed using the Penman-Monteith method in CROPWAT 8.0 software. Results showed the spatial and temporal distribution of ETo with peaks in summer months. Areas with higher ETo values were near rivers and streams, which generally have more abundant vegetation. Areas with low ETo values were relatively dry, where pasture and grasslands dominated the landscape. Correlation results showed that no relationship exists between streamflow and ETo (r = 0.36) in the study area, hence, a significant relationship exists between rainfall and ETo (r = 0.86). The study recommends the use ofCROPWATmodel for computing ETo under arid and semi-arid climatic conditions for water resource management and planning.
Open Access
Assessing the environmental context of hand washing among school children in Limpopo, South Africa
(Tandonline, 2017) Bulled Nicola; Poppe Kara; Ramatsitsi Khuliso; Sitsula Londolani; Winegar Geoffrey; Gumbo Jabulani; Dellingham Rebecca; Smith James
Despite its simplicity and efficacy, the promotion of hand washing for disease prevention remains a challenge, particularly in resourcelimited settings. This article reports on a quasi-experimental schoolbased study that aimed to improve habitual hand washing. Significant increases in hand washing occurred following improvements in hygiene and sanitation facilities (School A: t = 13.86, p = 0.0052). Smaller increases in hand washing occurred following education (School A: t = 2.63; p = 0.012; School B, no infrastructure improvements: t = 1.66, p = 0.239). Health policy and programming need to pay greater attention to the interplay of the structural, social and individual dimensions of unique contextual environments that influence habitual behaviours.
Open Access
Contamination of Soil due to Leakages of Polychlorinated Biphenyls (PCBs) at a Vandalized Electrical Transformer Site
(2017) Nedzamba, R. M.; Gumbo, J. R.
Worldwide and including in South Africa, the use of polychlorinated biphenyls (PCBs) has been banned as these have been implicated in the destruction of the ozone layer. The lack of the protective ozone layer has been widely blamed for increase in global warming. Here we report on impact of PCBs from a human vandalized electrical transformer on the soil environment at the Rietvlei farm in Louis Trichardt. The particle analysis showed that the soil was sandy followed by loam and then clay. The soil pH was in the range 6.79 to 10.15. The soil moisture content was on average below 6.8%. The analysis of Mg, Al, Ca and K for Cation Exchange Capacity (CEC) was carried out to determine the fertility of the soil. The average CEC of the soil sample was 7.48 meq/g and therefore the soil was fertile and but lacked organic nutrients. However at this site where the transformer oil was spilled it was observed that no grass was growing. The analysis of samples by the GC-MS and GCECD at Waterlab and SABS showed that there were ultra-traces of PCBs in the soil samples. Probably the absence of grass growing at the contaminated site was due to presence of the ultra-trace levels of PCBs. Thus there is a need to improve plant growth at the contaminated site in order to prevent easy water infiltration that might contaminate groundwater supplies. Makhado local municipality draws some of its water supplies from borehole just 1 m from the contaminated site.
Open Access
Effects of calcination temperature and solution pH on the defluoridation potential of Al/Fe oxide-modified diatomaceous earth: metal leaching and sorbent reuse
(IWa Publishing, 2017) Izuagie, Anthony A.; Gitari, M.; Gumbo, Jabulani R.
An evaluation of the effects of calcination temperature and solution pH on the fluoride removal capacity of Al/Fe oxide-modified diatomaceous earth was carried out. The sorbent was observed to be most effective and stable within the pH range 6.70–8.12, where the lowest concentrations of Al and Fe (<1 mg/L) in treated water were recorded. Thus, sorbent loss was minimal at that pH range. It was observed that the sorbent lost its efficiency and stability at calcination temperatures above 600 WC. Inductively coupled plasma-mass spectrometer analysis of metals in supernatants and thermogravimetric analysis of the sorbent showed that there was substantive loss of Al and Fe from the sorbent at temperatures above 600 WC because of evaporation. K2SO4 solution proved to be the best regenerant for spent sorbent compared to NaOH and Na2CO3, which caused sorbent loss owing to high solution pH. The CO2 3 from Na2CO3 bound to regenerated sorbent so much that it could not be displaced by fluoride during subsequent defluoridation experiments. Sorbent regenerated with 0.1 M K2SO4 solution could reduce 10 mg/L fluoride in artificial water at a dosage of 0.8 g/100 mL by 81.8% and 67.2% at the second and third cycles, respectively.
Open Access
Approaches to the Evaluation of Teaching and Learning Methods at a University: Evidence from South Africa
(2017) Gumbo, Jabulani R.
An increasing number of students drop out of university in South Africa and throughout the world. The South African Council for Higher Education has introduced strategies to deal with high dropout rates, which include the improvement of teaching and learning through the Quality Enhancement Program. I hereby document and evaluate my teaching and learning methods. The data collection for this research involved student informal evaluation, formal evaluation and peer evaluation. The formative evaluation data was grouped in 14 themes with numbers in brackets representing the number of counts of student expression of [their free form]: good lecturer (51); stop pointing (12); request for softcopy of lecture notes (7); speak with a loud voice (5); time to write notes (4); field work/practicals (2);; do not understand lecture notes (2); lecturer coming late (2); lots of lectures notes and case studies are long (2); update notes (1); no double class on Friday (1); timetables are clashing (1); require a small tests (1); revision of lecture (1). The concerns for summative evaluation were: I was a good lecturer; issues on hard copies of lecture notes and feedback on assignments. With regard to peer evaluation, a fellow academic attended one of my lectures to make observations and review the teaching and learning procedures. I was able to observe that I ended my lectures too abruptly. As a result, the suggested approach was that gradually end the lectures with a series of questions that invoke a critical response from students and ask any student to summarize the lecture in three sentences. I have since implemented the student concerns.
Open Access
To Patent or Not to Patent: Which One is the Better Alternative?
(2017-07) Gumbo, J. R.
Publishing of research findings is an important activity in the academic fraternity. However, if the research findings are novel it is better to patent protect first and then publish later in an open forum. An invention is owned by you until it is patented. Patent is the culmination process of knowledge production and thus must be protected and then exploited for socio-economic gain. The patent process is long and arduous and involves the Technology Transfer Office of the Directorate for Research & Innovation. The process involves patent search, appointment of patent attorney and then writing in legal language the scientific invention. This aspect is important as this cover the areas or loopholes where others might infringe on the patent. The patent search involves the searching of the invention in all patent databases so not infringe on other patents. The patent attorney is an expert on law and also in scientific matters and will guide you in the patent search and drafting the patent document that outlines your invention. Once the provisional or complete patent is filed and registered nationally and or international (Patent Cooperation Treaty), the inventor(s) can then proceed to harvest the benefits of the patent for the next 20 years. Now the paper can be published in peer reviewed journal (open public forum). The inventors also gain two things: the patent and the publication. The benefits accrue to the inventors and applicant, in this case the University where the research was conducted. University Rankings take into account the patents held by universities annually. Thus taking a patent has more benefits and it is better to patent protect the novel idea and then publish later.
Open Access
PhD by Publication or PhD by Traditional Model: Which Way to Go?
(2017-07) Gumbo, J. R.
South Africa is at the cross-roads with the knowledge production economy. The DST target is 6000 PhD graduates per million by 2018. The knowledge economy is important for South Africa as it is the engine for economic growth. There is a link between knowledge production and economic growth of a country by comparing the citation intensity and the economic wealth of the country. In addition to the knowledge production other factors such as political and macro-economic factors, infrastructure investments, providing clean water and sanitation, roads must be in place for sustainable economic development. This can only be sustained through the ‛production of highly trained people’ the PhD students. But the trick is which PhD model should I take? On the PhD model, the ASSAF study showed that South Africa produced most of the PhDs through the traditional model. However, for South Africa to produce more PhDs in a shorter time period there is a need to move away from the traditional model and embrace other forms of PhD production. The alternative model is the PhD by publication. This is able to produce PhD graduates in shorter pace of time with high quality impact publications.
Open Access
The treatment of dye wastewater using natural South African magnesite
(OMICS International, 2017-07-22) Ngulube, Tholiso; Gumbo, Jabulani Ray; Masindi, Vhahangwele; Maity, Arjun
Discharging industrial colored wastewaters into aqueous environments can cause adverse effects on aquatic life due to the toxic nature of synthetic dyes. The present study aimed to evaluate the efficiency of using natural South African magnesite to remove an anionic dye from aqueous systems. The natural nanosorbent was characterized by Transmission Electron Microscopy, Fourier Transform Infra-Red and X-ray Diffraction analysis. Various important parameters namely contact time, initial concentration of dyes, magnesite dosage, solution temperature and solution pH were optimized to achieve maximum adsorption capacity. The XRD results revealed that raw magnesite contains magnesite, periclase, dolomite and quartz as the crystalline phases. Optimum conditions were observed to be 60 min of agitation, 0.1 g dosage of magnesite per 50 mL of aqueous solution, 40 mg/L initial dye concentration and room temperature. Removal of DR81 from aqueous solution was observed to be independent of initial pH of the aqueous solution. The adsorption ratio toward 40 mg/L of DR81 was 96.27%. The results indicate that natural South African magnesite is an efficient material for the removal of DR81. The magnesite, due to high accessibility, low cost and non-toxicity can be considered a good replacement option of other high cost materials used to treat colored wastewater especially in developing countries like South Africa
Open Access
A Review: Spirulina a source of bioactive compounds and nutrition
(2017-09) Gumbo, J. R.; Nesamvuni, C. N.
The attainment of the nutrition related sustainable development goals (SDGs) is a challenge to South Africa. Part of the challenge is related to access to affordable nutrition by poor communities. Spirulina presents with nutritional benefits including 50 to 70% protein, and all essential amino acids in complete balance, 5 to 10% lipids and 10 to 20% carbohydrates, 10 vitamins especially vitamin B12 and pro-vitamin A (β-carotene), minerals such as iron and one of the few sources of dietary γ-linolenic acid (GLA). Health factors linked to Spirulina include anticarcinogenic, hypocholesterolemic and antioxidant properties. Spirulina is part of the cyanobacteria family of the Arthrospira species. The challenges that are there is to ensure that the isolates are pure and free from microbial, chemical and physical contamination during the cultivation phase. The cultivation is either in closed semi-continuous batch systems or open raceway that are prone to contamination from environmental elements. This paper highlights Spirulina use as a potential strategy to meet nutrition related Sustainable Development goals.
Open Access
Effect of hysteresis on water flow in the vadose zone under natural boundary conditions, Siloam Village case study, South Africa
(2017-10-17) Arrey, I. A.; Odiyo, J. O.; Makungo, R.; Kataka, M. O.
A one-dimensional vadose zone model was used to simulate flow under natural boundary conditions. The effects of hysteresis and temporal variability of meteorological conditions were evaluated. Simulations were performed in HYDRUS-1D code for the period April 2013–January 2014 (6601 hours) at three different locations in a delineated portion of the sub-quaternary catchment A80A of Nzhelele with different soil textures. Soil hydraulic characteristics were estimated in a Rosetta library dynamically linked to the HYDRUS-1D model which is based on the numerical solution of a one-dimensional Richard’s equation. Analysis of the simulation results suggests that ignoring hysteresis for soils of similar textural class does not lead to any significant deviation of the model predicted soil moisture, unlike for soils with different textural classes
Open Access
Geochemical and Mineralogical Characterization of Gold Mine Tailings for the Potential of Acid Mine Darinage in the Sabie-Pilgrim's Rest Goldfields, South Africa
(2017-11-28) Lusunzi, Rudzani; Gumbo, Jabulani Ray; Yibas, Bisrat; Novhe, Obed
The environmental hazards arising from active and abandoned mine tailings are a cause for concern. We report on the presence of mineral-related environmental hazards in both Glynn Lydenburg and Nestor mine tailings, approximately 6 km apart and located in the Mpumalanga Province of South Africa. Based on XRD, shows a wide range of minerals: pyritic sulphide, quartz and mica. The XRF results showed that quartz was the dominant oxide in both the mine tailings; followed by Fe2O3 and Al2O3. Furthermore, trace elements, such as As, Cr, Cu, Pb, V and Zn, were also found which are hazardous to the environment.