10 research outputs found
Speciation of arsenic water and sediments from Mokolo and Greate Letaba Rivers, Limpopo Province
No full textThesis (M. Sc.(Chemistry)) -- University of Limpopo, 2017.Great Letaba and Mokolo Rivers are major sources of water for domestic use, agriculture and recreational activities in Limpopo Province, South Africa. These Rivers are predisposed to pollution sources from atmospheric deposition of mine dust, emissions from power stations and burning fuel, return flows from agriculture and municipal wastewater discharges and sewage effluents, which may potentially affect the quality of water and the inhabiting biota. Arsenic (As) is an element of prime concern in aquatic systems exposed to such pollution sources due to its toxicity to humans and aquatic life. The quantification and speciation of As in Mokolo and Great Letaba Rivers is important to assess the current levels and predict future trends in the quality of the two rivers. Speciation of As in water and sediments is crucial since the toxicity depends on its chemical forms. In this study, various analytical approaches were explored to precisely identify and quantify different As species in water and sediment samples collected from Great Letaba and Mokolo Rivers.
Sample preparation was carried out with an intensive care to efficiently identify and quantify As species. Identification of each species in the samples was based on matching standard peaks with retention times by simple injection of standards of As species into Hamilton PRP X100 column. The chromatographic separation and determination of As3+, dimethylarsinic acid (DMA), monomethylarsonic acid (MMA) and As5+ in water and sediment samples were achieved by on-line coupling of high performance liquid chromatography (HPLC) to inductively coupled plasma-mass spectrometry (ICP-MS). A novel extraction method for As species in sediments based on 0.3 M (NH4)2HPO4 and 50 mM EDTA showed no species interconversion during extraction. Baseline separation of four As species was achieved in 12 minutes using gradient elution with 10 mM and 60 mM of NH4NO3 at pH 8.7 as mobile phases. The analytical figures of merits and validation of analytical procedures were assessed and adequate performance and percentage recoveries ranging from 81.1 – 102% for water sample and 73.0 – 92.0% for sediments were achieved. The As species concentration in water and sediment samples were found in the range 0.224 – 7.70 μg/L and 74.0 – 92.0 ng/g, respectively. The DMA was not detected in both water and sediment samples.
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The As content in sediments depends on the solid phase partitioning between inorganic As species and trace elements such as iron (Fe), manganese (Mn) and aluminium (Al). Knowledge of the extent of this partitioning is important to evaluate the distribution and pathways of As in water, aquatic organisms and possible exposure of animals and human beings. Therefore, total concentrations of As, Fe, Mn and Al in water and sediment samples were determined using ICP-MS and inductively coupled plasma–optical emission spectrometry (ICP-OES). The analytical procedures were validated using standard reference materials (SRMs) with percentage recoveries of trace elements ranging 84.0 – 95.6% for water samples and 75.0 – 120% for sediments. The As, Fe, Mn and Al concentrations obtained were further assessed for safe drinking water, irrigation water and for sediments quality about standard guidelines. Moreover, As species concentrations correlated with Fe, Mn and Al and the observed interactions depend on the adsorption capacities between As species and these trace elements.
The inorganic species in water samples were also determined by employing off-line mode of solid phase extraction (SPE) procedure using multi-walled carbon nanotubes (MWCNTs) impregnated branched polyethyleneimine (BPEI) as an adsorbent material. The MWCNTs-BPEI characterised with X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and Thermogravimetric analysis (TGA) techniques indicated successful modification of the nanomaterial. The MWCNTs-BPEI exhibited selective retention of As5+ in the presence of As3+ in water samples with the achieved pre-concentration factor of 23.3. The retained As5+ was then eluted and detected using ICP-MS. A limit of detection (LOD) of 0.0537 μg/L and limit of quantification (LOQ) of 0.179 μg/L were achieved. The obtained percentage recovery of 81.0% validated the SPE procedure for selective retention of As5+. The As5+ concentrations determined after the SPE procedure were found in the range of 0.204 – 7.52 μg/L, which are in good agreement with As5+ results obtained using HPLC-ICP-MS
The role of Umkhonto we Sizwe (MK) in the national liberation struggle in South Africa with reference to the rural far northern Transvaal, 1976-1990
No full textIncludes bibliographical references (leaves 250-275)
Manyobonyobo : padi ya boitsholo
No full textDissertation (MA (Setswana))--University of Pretoria, 2007.The full text of this thesis/dissertation is not available online. Pending permission from the author/supervisor access may be provided on request. Read the abstract in the section 00front of this document.African Languagesunrestricte
Bioaccumulation and Human Health Risk Assessment of Arsenic and Chromium Species in Water–Soil–Vegetables System in Lephalale, Limpopo Province, South Africa
No full textThe accumulation of potentially toxic elements (PTEs) in water, soil and vegetables can pose a severe threat to the respective organisms and lead to human health risks upon exposure. Water, soil and vegetable samples were collected from the Mokolo River and its vicinity. Total concentration quantification and speciation analysis of chromium (Cr) and arsenic (As) were performed using inductively coupled plasma-mass spectrometry (ICP-MS) and high-performance liquid chromatography hyphenated to inductively coupled plasma-mass spectrometry (HPLC-ICP-MS), respectively. The total concentrations of Cr and As were below the maximum permissible levels (MPLs) set by the World Health Organization (WHO) and South Africa’s Department of Water Affairs and Forestry (DWAF) for drinking water. The soil quality guideline value of 64.0 µg/g for Cr was surpassed in most sites and posed a great risk to the vegetables growing in it, whereas the guideline value of 12.0 µg/g for As was surpassed in one sampling site. The observed high concentrations in soil could be linked to the use of fertilizers and atmospheric deposits introduced through coal burning by power stations. In vegetables, the total Cr concentration surpassed the recommended MPL of 0.5 µg/g, rendering the vegetables unsafe for human consumption. Concentrations ranging from 197 to 1180 ng/g and 374 to 17400 ng/g were detected for Cr(VI) and Cr(III), respectively. The consumption of vegetables containing high levels of Cr and As would result in health risks in adults and children as the total hazard quotient (THQ) exceeded 1. The consumption of some vegetables particularly by children could cause serious health risks as the THQ > 10 was observed for some Cr-contaminated vegetables. The incremental lifetime cancer risk (ILCR) threshold of 1 × 10−4 was exceeded, indicating that the overall consumption of vegetables had high cancer risks for adults and children. This study suggests that the consumption of vegetable samples would lead to health risks in the population
Effects of the eradication of the rule of male primogeniture on the customary law of succession
No full textThis article discusses the consequences of the abolition of the rule of male
primogeniture by closely and critically discussing the outcome of the Bhe v
Magistrate Khayelitsha case. Therefore, exposing the effect of
implementing and extending common law solutions as a means of
bringing customary law in line with the Constitution to achieve the right of
equality. Thus, the author advises that courts and the legislature should
have employed a different method rather than one of extending the
application of the Intestate Succession Act 81 of 1987, which subsequently
led to the promulgation of the Reform of Customary Law of Succession and
Regulation of Related Matters Act11 of 2009, to customary law of
succession. Summarily, this article cautions against imposing common law
solutions, directly or indirectly, on customary law challenges and advises
on utilising customary law institutions, mechanisms and/or remedies to
bring customary law in line with the Constitution.https://journals.co.za/journal/dejuream2024Private LawSDG-16:Peace,justice and strong institution
The Impact of Induced Industrial and Urban Toxic Elements on Sediment Quality
No full textAbstract: The increasing population has subjected rivers and streams to high levels of both industrial and domestic pollution. Significant environmental challenges have been brought about by their effects, particularly with regard to biota, ecosystem processes, soil quality, and groundwater pollution. This study examined the effects of human activity by applying pollution index models to evaluate the input of toxic elements in river sediments. Prior to sediment quality analysis, the total amount of arsenic (As), lead (Pb), cadmium (Cd), mercury (Hg), thorium (Th), and uranium (U) was determined in the concentration range of 1.09–10.0 mg/kg, 8.53–475 mg/kg, 0.12–0.16 mg/kg, 4.85–77.5 mg/kg, 3.14–5.9 mg/kg and 0.93–2.86 mg/kg, respectively. The enrichment factor, contamination factor, pollution load index, and geo-accumulation index revealed alarmingly high levels of Pb and Hg contamination at some sampling points, which are related to possible human input, ranging from severe enrichment to considerable contamination. The low ranges of pollution indices of some toxic elements suggest enrichment through the natural weathering process and atmospheric deposition. The Pearson correlation coefficient revealed a significant correlation between Pb-Fe and As-Fe, suggesting the possibility of acid mine contamination. Continual monitoring of river sediment is essential to minimize the impact of toxic elements to sustain sediment health and quality
Mapping Trends in Air Quality Research in South Africa: A Bibliometric Analysis, 1998-2024
No full textThe foundation of South Africa is the Constitution, which guarantees every citizen access to a safe and healthy environment. Despite a wealth of research on lower-income households, the effects of burning wood for cooking, heating, and comfort in South African homes are also affecting the air quality; even if the government is working very hard to put measures in place to improve air quality, it will be very difficult to accommodate every household in South Africa. South Africa's low-income urban settlements focus on air quality monitoring for policy formulation and strategy building and Lack of garbage removal services and systems is another characteristic of low-income communities that exacerbates ambient air pollution levels. Based on the quantity of South African publications and citations in air quality that are listed in the Scopus and Web of Science databases, the study used bibliometric analysis to look at the country's air quality and the factors that affect it. Data was collected from 1998 to 2024; the results show that air pollution, nitrogen dioxide and emissions are causing a risk to children, and also having a high impact in causing diseases like asthma, respiratory health and climate change is playing a critical role in increasing the risk. Moreover, the word cloud reflects a growing emphasis on certain air pollutants, including NO₂, PM2.5, black carbon, and SO₂. NO₂ has been linked to substantial health implications, including respiratory disorders, asthma aggravation, and cardiovascular issues
Credit local authors fairly on international research papers
No full textAs co-signatories on a consensus statement released this week (see B. Morton et al. Anaesthesia doi: 10.1111/anae.15597; 2021), we call upon all scientific journals to adopt a similar system to promote fairness in author contribution assessments for research conducted in low-to-middle income countries (LMICs) by teams that include author(s) from institutions in high-income countries (HICs). The system consists of a structured reflexivity statement that asks authors to answer a series of open-ended questions that broadly follow established authorship criteria (see www.icmje.org). These help to ensure that LMIC researchers and other disadvantaged groups such as women and early-career researchers are properly represented.Progress in addressing such imbalances has been slow (A. I. Obasi Lancet 396, 651-653; 2020 doi:10.1016/S0140-6736(20)31536-1). For example, a fifth of papers on COVID-19 in Africa contain no African authors and, among those that do, HIC authors almost always occupy the coveted first and last positions (A. V. Naidoo et al. Br. Med. J. Glob Health 6, doi:10.1136/bmjgh-2020-004612; 2021).Such reflexivity statements will encourage inclusive and open discussion of issues affecting equity, including capacity strengthening and research legacy in host countries.</p
The Pan African Thoracic Society Methods in Epidemiologic, Clinical and Operations Research Program: A story of success told through a history of publications
No full textObjectives: Despite bearing a substantial burden of respiratory diseases, low- and middle-income countries in Africa contribute little to the research literature. Since 2007, the Pan African Thoracic Society’s Methods in Epidemiologic, Clinical, and Operations Research (PATS-MECOR) program has been working to strengthen capacity in lung health research in Africa. The aim of this study was to assess the research productivity of previous PATS-MECOR participants.Materials and Methods: A systematic review of publications attributed to past PATS-MECOR participants up until 2018 was carried out using a systematic search strategy based on their names on PubMed database.Results: A total of 210 participants drawn from 21 African countries attended PATS-MECOR between 2007 and 2016, of which more than three-quarters (76.7%) had ever published. Of the total 1673 included publications, 303 (12.7%) had multiple course attendees as coauthors. The median publication per published participant was 5 (IQR 2–13) articles. The percentages of the first author, second authors, or last authors publications were 371 (22.2%), 239 (14.3%), and 99 (5.9%), respectively. The top three journals published in were PLOS One 108 (6.6%), Lancet 80 (4.9%), and the International Journal of Tuberculosis and Lung Disease 52 (3.2%). The median citation of their publications was 11 (4–26). There was approximately a double-fold rise in the publication output of participants in their 1st year following attendance to PATS-MECOR compared to the year before the course (123, 68.0% vs. 58, 32.0%).Conclusion: The PATS-MECOR training program has been successful in research capacity building for African investigators as evidenced by a growing publication track record. There is a need to ensure sustainability and for increased collaboration and networking among the trained critical mass of researchers in the continent
