| L’Oreal-UNESCO grant will support research to combat antimalarial resistance | http://www.sun.ac.za/english/Lists/news/DispForm.aspx?ID=9788 | | L’Oreal-UNESCO grant will support research to combat antimalarial resistance | Wiida Fourie-Basson (media: Fakulteit Natuurwetenskappe) | <p>A PhD-student in chemistry at Stellenbosch University, Jessica Thibaud, is one of six South African female scientists to have received a generous grant from L'Oréal's <em>Fondation L'Oreal</em> and UNESCO (the United Nations Educational, Scientific and Cultural Organisation).<br></p><p>The <a href="https://www.unesco.org/en/prizes/women-science">L'Oréal-UNESCO For Women in Science international programme</a> provides support to female scientists at all stages in their scientific careers. According to an official media release, women still represent just 33.3% of researchers globally, and their work rarely gains the recognition it deserves.</p><p>Jessica's research focuses on identifying new chemical compounds to disrupt the life cycle of the malaria parasite <em>Plasmodium falciparum </em>after it enters the human host. It is no easy task to identify these compounds, however, as there are literally thousands/millions stored in databanks all over the world. </p><p>In 2020, malaria, a mosquito-borne parasitic disease was responsible for some 627 000 deaths worldwide, of which 96% were in Africa. The parasite is also showing increased resistance to antimalarial medication currently in use.</p><p> Jessica's research is just one aspect of a larger research focus on the design and development of antimalarial drugs, led by <a href="http://www0.sun.ac.za/chemistry/antimalarial-drug-design-and-development/">Dr Katherine de Villiers</a> in SU's Department of Chemistry and Polymer Science. Dr de Villiers' research group recently developed a two-dimensional map of antiplasmodium chemical space. Generated using a simple principal component analysis algorithm, the map visually clusters together those compounds with known antimalarial activity. For her MSc-studies under Dr de Villiers, Jessica combined this map with recently acquired skills in machine learning to identify a subset of 6 000 compounds that showed potential of targeting a specific enzyme in the parasite's life cycle. </p><p>Since beginning her PhD, Jessica has benefitted from further training provided through the <a href="https://h3dfoundation.org/about/">H3D Foundation</a> at the University of Cape Town and <a href="https://www.ersilia.io/">Ersilia</a> in the use of machine learning and Artificial Intelligence to speed up the process of discovering new drugs. Using these computational methods, she was able to narrow down the search even further to a potential 30 compounds. She is now in the process of testing these compounds in the laboratory to find the one or two with the most potential for further development. </p><p>“Apart from their anti-malarial activity, these compounds also have to show important drug-like characteristics such as solubility, selectivity, and potency before they can be considered for further development," she explains.</p><p>She plans to use the L'Oreal grant for a more powerful computer to use in the laboratory, and to attend an international congress on bioinorganic chemistry later this year. As part of the grant she also attended a week-long training programme for the 25 African L'Oreal-UNESCO laureates in the Côte d'Ivoire.<br></p><p><br></p> |
| Artificial Intelligence boost for SU research on long-Covid | http://www.sun.ac.za/english/Lists/news/DispForm.aspx?ID=9777 | | Artificial Intelligence boost for SU research on long-Covid | Faculty of Science (Wiida Fourie-Basson) | <p>Research at Stellenbosch University (SU) into long Covid has received an “Artificial Intelligence" boost worth over R11.75 million (€600 000) over the next three years via the <a href="https://www.erasmus.ai/">Erasmus.AI search engine</a>.</p><p>The Erasmus.AI engine, lead by SU alumnus <a href="https://danielerasmus.com/">Daniel Erasmus</a>, is an immensely powerful search engine that can analyse web-scale large bodies of unstructured text – in practice over 250 000 000 URL's are processed per day and translating from fifteen different languages. This includes all open access research articles and abstracts published on <a href="https://pubmed.ncbi.nlm.nih.gov/about/">PubMed</a>.</p><p>“If you consider that nearly 5 000 medical articles are published each day, one realises there is no way that a medical specialist or researcher can remain current. We are here to give overview, enhance collaboration, in short − to change the architecture of discovery," Erasmus explains during a recent visit to SU.</p><p>The purpose of the visit was to sign a research agreement with physiologist Prof Resia Pretorius, head of the Department of Physiological Sciences and currently at the forefront of research efforts worldwide to understand <a href="https://cardiab.biomedcentral.com/articles/10.1186/s12933-021-01359-7">the role of persistent microclots</a> in the blood samples of individuals suffering from long COVID. Current thinking is that these insoluble microclots inhibit or even temporarily block blood flow in capillaries and subsequent oxygen transfer to tissue. The lack of oxygen in various parts of the body can account for many of the symptoms of long Covid. </p><p>Even more intriguing, however, is the presence of a significant number of large molecules known to significantly reduce the body's ability to regulate clot formation, trapped in these microclots, as well as a range of antibodies. In an article published in October 2022 in the journal <a href="https://pubmed.ncbi.nlm.nih.gov/36131342/">Cardiovascular Diabetology</a>, Pretorius and co-authors write that these antibodies may have significance in the immune response following acute Covid-19 illness, or driving auto-immunity in some individuals with long Covid. There is however little to no data available on these antibodies.</p><p>Pretorius and her research team have since been combing research data bases for clues to better understand the role and function of some of these antibodies.</p><p>Now, with access to the Erasmus.AI search engine and platform, they can harness the super-computing power of AI to do the searching for them, as well as visualise in one go what is out there by means of a user-friendly interface.</p><p>Pretorius is also curious to better understand the ability of enzymes such as serrapeptase and nattokinase to break down blood clots: “Currently we only have anecdotal evidence from individuals who reported improved symptoms after taking these enzymes," she explains. But maybe there is something in the literature out there that we have overlooked.</p><p>According to Erasmus, AI can provide researchers with clinical, laboratory and anecdotal reports from billions of sources out there: “AI can provide an overview where none existed. It is like a 'super Google' for professionals. Generative AI brings together the insight associated with a large-scale view, and when combined with serendipitous discovery, it most often leads to new insight and understanding," he explains.</p><p>This combination of human and artificial intelligence is what is needed to tackle the global health crisis brought on by long Covid, he adds: “The impact of long Covid is going to dwarf the pandemic phase. We need to deal with long Covid as a matter of urgency," he warns.</p><p>Erasmus, who obtained his degree in engineering at SU, is currently based in Amsterdam in The Netherlands.<br></p><p><em>On the photo above, from left to right, Prof. Louise Warnich, Daniel Erasmus, and Prof. Resia Pretorius. Photo: Ignus Dreyer</em><br></p><p><br></p> |
| Wood Science students are supporting the STEM@Maties programme | http://www.sun.ac.za/english/Lists/news/DispForm.aspx?ID=9754 | | Wood Science students are supporting the STEM@Maties programme | Prof Martina Meincken | <p>The STEM@Maties programme is aimed at previously disadvantaged high schools to familiarise learners with experimental techniques and possible project ideas. About ten schools from the Stellenbosch / Winelands region participated.</p><p>Karl Kutzer and Keenan Nefdt from the Department of Forest and Wood Science presented various analytical techniques used to characterise the acoustical properties of wood and explained how properties, such as density, or moisture content affect sound propagation.<br></p><br> |
| Results from recent MSc study provides design values for SA Pine CLT | http://www.sun.ac.za/english/Lists/news/DispForm.aspx?ID=9746 | | Results from recent MSc study provides design values for SA Pine CLT | Prof Brand Wessels | <p>Mr MJ Jacobs (centre) successfully defended his MSc thesis with the title 'Out-of-plane strength and stiffness prediction of SA Pine cross-laminated timber'. The most important conclusion was that the shear analogy method gave the best predictions for strength and stiffness of SA Pine cross laminated timber (CLT). A table of unfactored resistance for three-, and five-layer layups using South African strength classes was produced and structural engineers in South Africa can use that table for designing CLT buildings from SA Pine. Since submitting his thesis, MJ has worked at XLAM South Africa and has now been appointed as Director at Holzbau CPT where he was responsible for setting up a new local glulam factory. MJ is pictured here with Mr Michael Kloos (left), a structural engineer who often designs CLT buildings, and his supervisor Prof. Brand Wessels (right). The future for CLT looks bright and we wish MJ well as he embarks on his career! <br></p> |
| When climate change leaves you with the only (most expensive) option to adapt | http://www.sun.ac.za/english/Lists/news/DispForm.aspx?ID=9739 | | When climate change leaves you with the only (most expensive) option to adapt | Wiida Fourie-Basson (Faculty of Science) | <p>There may come a time in our efforts to gradually adapt to climate change that we are pushed over a tipping point – when the only choice we face is either a completely transformed way of doing things, or nothing.<br></p><p>These so-called tipping points in adaptation are, however, going to be very capital and technology intensive, warns Prof Guy Midgley, interim director of the School for Climate Studies (SCS) at Stellenbosch University. He is the main author on a recent article, “<a href="https://stellenbosch-my.sharepoint.com/personal/science_sun_ac_za/Documents/Departemente/Botany%20and%20Zoology/Guy%20Midgley/2023_Tipping%20points/Potential%20tipping%20points%20for%20climate%20change%20adaptation%20costs">Potential tipping points for climate change adaptation costs</a>", published in the journal <em>Climate and Development</em>. The other authors are Prof Arthur Chapman, also from SCS, and Julio Araujo from SouthSouthNorth, a non-profit organisation working in the field of climate change resilience in Africa.</p><p>According to Prof Midgley there tends to be a focus on low-risk adaptation responses in the literature, mostly due to high levels of uncertainty about the impacts of climate change. </p><p>In the case of Africa, however, our adaptation capacity is already regarded as limited. In the latest Intergovernmental Panel on Climate Change (IPCC) report on Africa, breaching adaptation limits is one of the critical risks facing African countries.</p><p>In the article, they identify three phases of human adaptation to a changing climate. Firstly, in the “coping adaptation phase", the responses are inexpensive, largely reactive, and involve low-cost beneficiation of existing technologies. </p><p>Once these coping mechanisms are no longer effective, there is a transition to more deliberate efforts to find alternative technologies or practices, accompanied by an increase in costs. However, the essential characteristics of the sector are still retained.</p><p>The third phase is "strongly technology dependent and/or capital-intensive" and characterised by novel management techniques and practices that alter the essential character of the sector in question and transform it, often associated with a further steep rise in costs. </p><p><strong>What does this mean for food production and nature-based livelihoods in Africa?</strong></p><p>According to the authors, one of Africa's key vulnerabilities is the sensitivity of agricultural production to drought and heat stress, and the link between crop failures and nature-based livelihoods. </p><p>This means many communities rely on indigenous knowledge systems and local knowledge to adapt to the impacts of climate change. This is typical of the low-cost adaptation response phase. In the case of Rwanda, for example, tea production is currently limited to elevations between 1600 and 2100 metres above sea level, due to its sensitivity to heat stress.</p><p>Warming of 1 degree Celsius will shift this suitable elevation band about 160 metres higher. Tea production is also impacted by rainfall variability – less rain resulting in a smaller crop. Relying on their intimate knowledge of the area and its vegetation, local farmers can still adapt by relying on these signals.</p><p>However, as future warming and greater rainfall variability are predicted for that region, the adaptation responses become more costly, such as planting shade-providing trees and physically relocating tea plantations upslope, or using shade cloths and misting. When these do not work anymore, we enter the third and much more expensive phase, such as the physical relocation of the cropping area. </p><p>In this phase, local farmer's knowledge loses its effectiveness. </p><p>According to the authors, as indigenous knowledge systems start to fail, it will require even more costly technological solutions: “If this is the case," they write, “then African countries face a significant loss of value that is not currently considered in economic terms – the loss of generations of hard-won indigenous local knowledge".</p><p><strong>Strengthening policy making and planning in Africa</strong></p><p>Prof Midgley says they hope their identification of these tipping points in adaptation investment will help policy-makers and planners to better understand what lies ahead, as well as strengthen their stance during negotiations on the global mitigation goal.</p><p>“A focus on identifying adaptation cost tipping points would enhance the immediate value of climate impacts and adaptation research for policy makers and planners, especially in developing country regions such as Africa," they conclude. <br></p><p><em>Contact science@sun.ac.za for media interviews.</em><br></p><p>Photo: Rwandan tea plantations around Nyungwe national park. Photo credit: Ben Ayobi wikicommons - <span></span>https://commons.wikimedia.org/wiki/File:Foggy-sunrise-rwanda.ngsversion.1474048474112.adapt.1900.1.jpg<br></p> |
| Welcome to our new 1st year Forest and Wood Product Science students -2023! | http://www.sun.ac.za/english/Lists/news/DispForm.aspx?ID=9726 | | Welcome to our new 1st year Forest and Wood Product Science students -2023! | Prof Bruce Talbot | <p>Welcome to our new 1st year Forest and Wood Product Science students -2023!<br></p> |
| New study reveals unexpected diversity of South Africa’s ecologically important long-tongued flies | http://www.sun.ac.za/english/Lists/news/DispForm.aspx?ID=9710 | | New study reveals unexpected diversity of South Africa’s ecologically important long-tongued flies | Wiida Fourie-Basson (Faculty of Science) | <p></p><p>A detailed study of over 50 long-tongued fly species endemic to Southern Africa has shown that species known to science only account for about half of the diversity of this ecologically important pollinator group.</p><p>Southern Africa's long-tongued flies (Nemestrinidae) are unique for their exceptionally long proboscises. The most well-known is <a href="/english/Lists/news/DispForm.aspx?ID=6593"><em>Moegistorhynchus longirostris</em> </a>with a proboscis that reaches a remarkable 90 to 100mm in length – with a body length of 15 mm, the proboscis is more than five times the length of its body. These long-tongued flies are the only pollinators of many long-tubed flowers such as the critically endangered <em>Hesperantha oligantha</em>,<em> </em>endangered species such as <em>Disa scullyi</em> and the dwarf nerine (<em>Nerine humillis</em>), as well as various <em>Pelargonium</em>, <em>Plectranthus</em>, <em>Gladiolus</em>, <em>Watsonia</em> and <em>Lapeirousia</em> species. </p><p>Yet, despite being so charismatic, the family has received little taxonomic attention. The last revision of known southern African nemistrinid species was published more than 90 years ago, and included 44 named species.</p><p>In a recent paper, published in the journal <em>Invertebrate Systematics</em>, <a href="https://pollinationresearch.wordpress.com/genevieve-theron/">Dr Genevieve Theron</a> and colleagues estimates that more than half of the South African species in the Nemestrinidae family are currently undescribed. The work formed part of her doctoral research at the Centre for Functional Biodiversity at the University of KwaZulu-Natal, and included contributions from scientists at UKZN, Stellenbosch University and Rhodes University.<br></p><p><img src="/english/PublishingImages/Lists/dualnews/My%20Items%20View/edits_Genevieve%20Theron_Photocredit_Wiida%20Fourie-Basson%20(10).jpg" alt="edits_Genevieve Theron_Photocredit_Wiida Fourie-Basson (10).jpg" class="ms-rtePosition-2" style="margin:5px;width:216px;" /></p><p>Population ecologists use mark-recapture techniques to estimate the population sizes of animals like rhinos. Here, they have a known number of marked animals in a population and by using the ratio of marked to unmarked animals observed during surveys, it is possible to estimate the total population size. Dr Theron used a similar technique to estimate long-tongued fly diversity. </p><p>The research team collected 136 specimens from their known range in South Africa, Eswatini and Lesotho. Dr Theron then used DNA sequencing and morphological analysis to show that there were actually at least 58 distinct species, of which only 29 were currently recognised species. The remaining 29 could not be identified and therefore probably represent species that have not yet been described, suggesting that actual fly diversity is double the described diversity.</p><p>“We estimate that the total nemestrinid diversity in southern Africa may eventually add up to more than 80 species," she explains.</p><p>According to <a href="https://pollinationresearch.wordpress.com/dr-timo-van-der-niet/">Prof Timo van der Niet</a>, associate professor at the Centre for Functional Biodiversity at UKZN and senior author on the paper, the paper challenges the common perception among the public that most species are known to science.</p><p>“This study shows that even in a country like South Africa, with a strong tradition of natural history, much of the invertebrate diversity is likely undescribed. If this is the case for a charismatic group like long-tongued flies, it is likely even more the case for smaller insects," he warns.<br></p><p><a href="https://www.bruce-anderson-stellenbosch-university.com/">Prof Bruce Anderson</a>, an evolutionary biologist in the Department of Botany and Zoology at Stellenbosch University (SU) and co-author, says studies such as this one contribute significantly towards improved estimates of global insect diversity and are important for a better understanding of local ecology and conservation.</p><p>“We used to think that there were about 150 plant species that were completely reliant on about nine long-tongue fly species for pollination. If these flies were to disappear, many rare and endangered South African plants would probably go extinct," he explains.</p><p>But this study suggests that the ecologically important long-tongue fly species may represent more than nine distinct taxa. Furthermore, many of the undescribed fly species are likely to be involved in intricate plant interactions of their own, expanding their importance well beyond what is currently thought, he adds.</p><p>Dr Theron's task for the next three years, as a postdoctoral fellow at the KwaZulu-Natal Museum, will be to identify and describe those 29 unknown species (and many others held in collections all over the world). </p><p>The researchers hope that the findings from the study will provide a valuable basis for future conservation strategies for this important pollinator group.</p><ul><li>The paper titled “We don't know half of it: morphological and molecular evidence reveal dramatic underestimation of diversity in a key pollinator group (Nemestrinidae)" was published 5 January 2023 in the journal <a href="https://www.publish.csiro.au/IS/IS22023"><em>Invertebrate Systematics</em></a>.<br></li></ul><p>On the images above, Long-tongue flies must fully insert its proboscis into the flower to obtain a tiny droplet of nectar at the bottom of the tube. In the process pollen is placed on or removed from its head by the long-tubed iris, <em>Lapeirousia anceps</em> (on the left) and the endangered <em>Nerine humillis</em> (on the right). <em>Images: Bruce Anderson and Ethan Newman</em><br></p><p><strong>Media interviews</strong></p><p>Dr Genevieve Theron</p><p>E-mail: genevieveltheron@gmail.com</p><p>Mobile: +27 82 591 0515</p><p> </p><p>Prof Timo van der Niet</p><p>E-mail: vdniet@gmail.com</p><p>Mobile: +27 728191439</p><p> </p><p>Prof Bruce Anderson</p><p>E-mail: banderso.bruce@gmail.com</p><p>Mobile: +27 72 113 6948<br></p><p><em><br></em></p> |
| The Department of Forest and Wood Science graduated three PhD students in December 2022. | http://www.sun.ac.za/english/Lists/news/DispForm.aspx?ID=9708 | | The Department of Forest and Wood Science graduated three PhD students in December 2022. | Prof Martina Meincken | <p>Sadiq Mohammed, Charles Mulenga and Russel Morkel (not in the photo) successfully completed their PhD studies despite the interruption caused by Covid-19 and the difficulties that followed, and graduated in December 2022. Sadiq Mohammed investigated the feasibility of manufacturing wood plastic composites from invasive trees and recycled plastic to be used as building materials in the Reconstruction and Development Programme (RDP) houses. Charles Mulenga analysed the effect that mining pollution has on the growth characteristics of indigenous trees in the Copperbelt area. Russel Morkel determined the moisture loss of wood logs during rail transport from the plantation to the mill. Well done guys – we are proud of you! <br></p> |
| Portraits from the Pandemic – “We are all doing our best" | http://www.sun.ac.za/english/Lists/news/DispForm.aspx?ID=9629 | | Portraits from the Pandemic – “We are all doing our best" | Wiida Fourie-Basson, Faculty of Science | <p>From old souls who collect teas from across the world, to a burnt-out lawyer and a writer who has lost her sparkle. For those of us dealing with intense anxiety and burnout after the pandemic, the quaint watercolour-painted animal characters in <em>Portraits from the Pandemic </em>remind us “that we are all united in our brokenness".</p><p><em>Portraits from the Pandemic</em> is written and illustrated by Karin-Therese Howell, a mathematician and associate professor in the Department of Mathematical Sciences at Stellenbosch University. </p><p>The mother of two created and painted 40 unique sketches of a range of forest folk writing about their experiences during the pandemic to the local forest newspaper, <em>The Daily Oak</em>. This was her way of dealing with the stress and anxiety of living through the unknowns of the pandemic and the hard lockdown.<br></p><p><img src="/english/PublishingImages/Lists/dualnews/My%20Items%20View/Meet%20Juniper.jpg" alt="Meet Juniper.jpg" style="margin:5px;" /><br></p><p>These forest folk include, inter alia, a dedicated Grade 2 teacher, an emphatic architect, a mathematician suffering from imposter syndrome, the owner of a bakery, a recent divorcee, a married couple seeking counseling, a depressed journalist and a stressed-out student in mathematics living on coffee and Red Bull. </p><p>But while all of this may sound quite depressing, the beauty of the characters is found in how they are portrayed as sensitive souls, dealing with intense burnout and anxiety in their own special ways. Jeff the journalist, for example, has learnt to cope with his depression “by viewing the world upside down while breathing deeply and engaging all his senses". Christopher the burnt-out lawyer has quit his high-flying career and now works in a pet shop, living with his four pet mice on a small holding. </p><p>A few of the characters are also dealing with neuro-diversity challenges. The little owl character Lisa, for example, has auditory processing disorder. But because she was only diagnosed as a teen, many lyrics of the A-Ha songs she memorised are wrong. But that does not disturb Lisa: “She thinks many of them are more beautiful as she has them stored. Sound is a colour for Lisa, and silence a rainbow", reads the sketch.</p><p>Fundamental to each sketch is a deep empathy and the believe that “no hare should be left behind, excluded or just accommodated". That is why the last three characters in the book are Daisy, Lilly and Rosy. They are three moms who have started a campaign for the inclusion of neuro-diverse children at schools.</p><p>With this quaint little book, Karin-Therese also wants to raise awareness of a poorly understood neurodevelopmental condition that remains largely undiagnosed, even though it affects up to 7% of school-going children in the United States. This condition is known as development coordination disorder (DCD).</p><p>According to Dr Eileen Africa from the Division of Movement Science and Exercise Therapy at SU, children with development coordination disorder (DCD) typically present with poor postural control, lower muscle tone, slower movements, delayed action and -response times and coordination. But while the gross motor delays typically associated with DCD are easily observable with the naked eye, these difficulties are often misunderstood as laziness or behavioral problems.</p><p>“They tend to be viewed and labelled as clumsy and uncoordinated and are often teased or bullied by their peers. They struggle with daily activities such as riding a bicycle, getting dressed, eating, self-care, and many other skills that otherwise come naturally to a neurotypical child of the same age," Dr Africa explains. </p><p>This condition can persist into adulthood and therefore early recognition, diagnosis and intervention are paramount.</p><p><em>Portraits from the Pandemic</em> is available in two formats and is available in major book and gift stores or can be ordered directly from the author: Insta: @jupiterjune612, Facebook: karinthereseart</p><p>“I hope readers will sense some parts of themselves in these sketches," she writes: “We are all a little broken and doing our best."</p><p>For more information about development coordination disorder, <a href="https://eur03.safelinks.protection.outlook.com/?url=https://canchild.ca/en/diagnoses/developmental-coordination-disorder&data=05%7c01%7c%7cecf742a4e35d4a40a37708dac71be048%7ca6fa3b030a3c42588433a120dffcd348%7c0%7c0%7c638041219793651160%7cUnknown%7cTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7c3000%7c%7c%7c&sdata=BnDvcoitpw3RwPBumF2SaExvnPjHn0mLC3cREUFqqEs%3D&reserved=0">https://canchild.ca/en/diagnoses/developmental-coordination-disorder</a></p><p> </p><p><br></p> |
| Building capacity to monitor for pesticide pollution in Western Cape rivers | http://www.sun.ac.za/english/Lists/news/DispForm.aspx?ID=9631 | | Building capacity to monitor for pesticide pollution in Western Cape rivers | Wiida Fourie-Basson, Faculty of Science (media) | <p></p><p>Geoenvironmental scientists at Stellenbosch University (SU) are working with the <a href="https://www.eawag.ch/en/">Swiss Federal Institute of Aquatic Research</a> (Eawag) in Switzerland to develop in-house capacity to monitor for aquatic pesticide pollution.</p><p>Dr. Reynold Chow, a hydrogeologist in the <a href="/english/faculty/science/earthsciences">Department of Earth Sciences</a> at SU, says South Africa is the leading pesticide user in Sub-Saharan Africa, but due to the cost and expertise associated with this kind of monitoring, there is limited data from most developing countries on pesticide pollution.</p><p>To address this gap, Eawag has donated a set of chemical standards to the <a href="/english/research-innovation/caf/units-laboratories/mass-spectrometry">Mass Spectrometry Laboratory</a> in SU's Central Analytical Facilities (CAF). These chemical standards are very expensive, but necessary to develop the chemical analytical methods to detect and quantify these compounds in environmental samples.</p><p>Dr. Chow says we should be as concerned about pesticide pollution as the residue on exports: “While there are strong regulations regarding the levels of pesticide residue on exports, there are no regulations in South Africa for restricting levels of pesticide pollution in the environment, particularly in water. This is a problem for the environment, as well as rural communities in South Africa that rely on groundwater for drinking water.<br></p><p>“In other words, we have to live with the consequences of environmental pesticide pollution in our local ecosystems, while countries that import South African produce do not. This means they are literally externalizing the environmental impacts of pesticide pollution to South Africans," he warns.<br></p><p>In a recent study, Dr. Chow worked with scientists from Eawag, the Swiss Tropical and Public Health Institute, the University of Basel and the Centre for Environmental and Occupational Health Research at the University of Cape Town to monitor pesticide pollution of waters in three agriculturally intensive river catchments in the Western Cape: Grabouw, Hex River Valley, and Piketberg. These areas are well-known for its wheat, deciduous fruit, wine, and citrus industries.<br></p><p>Over a sampling period of more than a year and testing for 101 pesticides, they found that surface waters across all three catchments contained at least three pesticides, while the majority (83%) of the samples contained five or more pesticides. These analyses were done at Eawag.<br></p><p>Two of the three catchments, Hex River Valley and Piketberg, raised concern because of high concentrations of certain pesticides over longer time periods. Analysis of samples from the Hex River Valley showed the persistence of terbuthylazine and imidacloprid for 22 weeks, while terbuthylazine and metsulfuron-methyl persisted for up to four weeks in the Piketberg catchment.<br></p><p>Terbuthylazine is a herbicide for the control of the emergence of a broad spectrum of annual weeds in apples, vines and citrus. Metsulfuron-methyl is a herbicide which kills broadleaf weeds and some annual grasses. Imidacloprid is an insecticide that mimics nicotine, which is naturally found in many plants and which is toxic to insects. Since 2013 it has been banned as a pesticide of concern in the European Union, as it has been found in honey worldwide and <a href="https://modernfarmer.com/2021/03/why-are-banned-bee-killer-neonicotinoids-still-being-used-in-europe/">as an insecticide may be responsible for declining honey-bee populations</a>.</p><p>Dr. Chow says current thinking is that the pesticides found in the rivers are unrelated to agricultural spraying (in the case of terbuthylazine and imidacloprid): “There are either other non-agricultural sources, such as forestry or urban areas, that we are unaware of, or these pesticides are leaching into the groundwater where they are gradually transported to rivers all year round."<br></p><p>To better understand the potential environmental and human health risks, they propose continuous and consistent monitoring programs for pesticide pollution in agriculturally intensive catchments, coupled with a recording system of pesticide use by farmers. “Only then will we be able to develop context-specific risk thresholds and sustainable agricultural practices that will benefit both the environment and our economy," he concludes.<br></p><p>The study, titled “Seasonal drivers and risks of aquatic pesticide pollution in drought and post-drought conditions in three Mediterranean watersheds", was published in the journal <em>Science of the Total Environment</em> recently. It is open-access and available online at: <a href="https://www.sciencedirect.com/science/article/pii/S004896972206884X">https://www.sciencedirect.com/science/article/pii/S004896972206884X</a></p><p><strong>On the photo above: </strong>MSc-student Emma Davies is currently completing an internship at Eawag where she is receiving training in the methodology of pesticide analysis on an Agilent 6495C triple quadrupole Liquid Chromatography/Mass Spectrometry (LC/MS) system. Here she is with her co-supervisor Dr Christian Stamm. <em>Image provided</em></p><p><br></p> |
