Browsing by Author "Matovu, Henry"
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Item Electronic wastes in sub-Saharan Africa : a critical review of environmental and health impacts, regulatory responses, and future perspectives.(Elsevier Inc., 2025) Ssebugere, Patrick; Miiro, Ashirafu; Matovu, Henry; Odongo, Silver; Kato, Charles Drago; Babirye, Prudence Mary; Nabuuma, Josephine; Sillanpaa¨, Mika; Sifuna, Douglas; Nyakairu, George WilliamRecent technological advancements coupled with lax policy regulations have caused increased electronic waste (e-waste) burden in the Sub-Saharan Africa (SSA), thereby exacerbating the environmental signatures of hazardous substances including contaminants of emerging concern (CECs), endocrine-disrupting chemicals (EDCs), persistent organic pollutants (POPs), and toxic metals such as lead (Pb), mercury (Hg), and cadmium (Cd), among others. This review synthesized 62 studies published between 2008 and 2025 to assess the environmental and health risks associated with e-waste disposal in SSA. Pb, Hg, Cd, and brominated flame retardants were the most detected hazardous substances. Near e-waste sites, Pb levels in soil ranged from 120 to 14,000 mg/kg, while Cd reached 6.8 mg/kg in topsoil. Water contamination by Hg near informal processing sites ranged from 0.3 to 2.8 µg/L, exceeding the U.S Centers for Disease Control and Prevention (CDC) safety thresholds. Air pollution from open burning releases polycyclic aromatic hydrocarbons (400–1800 ng/m3), dioxins (3.5–19.2 ng/m3), and volatile metals, worsening the environmental health crisis. Informal recycling practices were the primary source of these pollutants, exposing workers and nearby communities to these toxic substances. This review highlighted significantly elevated health risks, with widespread exceedance of safety thresholds (e.g., blood Pb levels up to 309 µg/dL, compared to CDC reference: 5 µg/dL; Cd up to 8.5 µg/L), leading to cognitive deficits, neurological damage, cancer, and respiratory and reproductive disorders, particularly for the vulnerable populations. Observed trends, gaps in recycling infrastructure and policy underscore the urgent need for improved legislation, formal recycling systems, and public awareness to mitigate health risks in the SSA. Keywords: E-waste, Sub-Saharan Africa, EDCs, Heavy metals, Recycling, ExposureItem Enhancing student learning through video feedback and structured reflection.(The University of Sydney, 2025) Murphy, Thomas J.; Scarratt, Liam R. J.; Black, Jeffrey; Naeyaert, Pierre; Matovu, HenryFormative assessment plays a critical role in promoting learning by providing students with timely, actionable insights into their performance (Hattie & Timperley, 2007). Developing feedback literacy, i.e. the ability to understand, interpret, and use feedback, is essential to fostering self-regulated learning (Carless & Boud, 2018; Nicol & Mackfarlane-Dick, 2006). Yet, many students struggle to act on feedback meaningfully, often engaging with it superficially, particularly in the context of automatically marked online MCQ quizzes (Henderson et al., 2019). To address this challenge, this study evaluates a formative feedback and reflection cycle for asynchronous online MCQ quizzes in a first-year chemistry course, designed to enhance students’ feedback literacy and learning outcomes. Following an incorrect response, students watch a concise, instructor recorded lightboard video explaining the underlying misconception, complete a structured reflection, and then attempt a similar question. The study assesses the impact of this cycle on student performance and, through a thematic analysis of their reflections, investigates how students engage with the feedback. We will also examine student perceptions of the intervention’s usefulness to provide practical guidance for educators. Keywords: Video feedback, Formative Feedback, student engagement, Artefact analysisItem ‘‘It is not just the shape, there is more’’: students’ learning of enzyme–substrate interactions with immersive virtual reality.(The Royal Society of Chemistry, 2024) Matovu, Henry; Won, Mihye; Tasker, Roy; Mocerino, Mauro; Treagust, David Franklin; Ungu, Dewi Ayu Kencana; Tsai, Chin-ChungImmersive Virtual Reality (iVR) can help students visualise and explore complex chemical concepts, such as protein enzyme structures and interactions. We designed a set of collaborative iVR-based learning tasks on the interaction between a protein enzyme and its substrate. We investigated how 18 pairs (36 students) in undergraduate chemistry courses changed their understanding of enzyme–substrate interactions through iVR learning tasks. Videos of pre- and post-interviews and student-generated diagrams were analysed. Before iVR, students had abstract models of the structure of a protein enzyme or its interaction with a substrate molecule. Over 90 per cent of the students (33/36) explained enzyme– substrate interactions using simplistic lock-and-key diagrams, exclusively focusing on the shape. Although many students employed key scientific terms like activation energy in their explanations, they were unsure how enzymes lowered activation energy or how catalytic reactions occurred. After iVR, all students discussed the inadequacy of 2D diagrams for representing complex enzyme–substrate interactions. About 90 per cent of students (32/36) used concrete ideas such as electron density and orientation of reactants in the active site to explain the probability of successful interactions between the enzyme and its substrate. Our findings provide evidence of how interactive iVR learning tasks can help students explore complex molecular structures, integrate ideas, and build a concrete understanding of challenging science concepts.Item Legacy and emerging organic pollutants in indoor and outdoor environments in Africa : contamination levels, health risks, and analytical techniques.(Elsevier B.V., 2025) Muhwezi, Godfrey; Kyarimpa, Christine; Gumula, Ivan; Nagawa, Christine Betty; Omwoma, Solomon; Matovu, Henry; Matsiko, Julius; Odongo, Silver; Sifuna, Douglas; Spanik, Ivan; Kato, Charles Drago; Ssebugere, PatrickThe World Health Organisation reported that over 20 % of the global disease burden and deaths are caused by environmental factors such as air and dust pollution. Legacy organic pollutants (LOPs) and emerging organic pollutants (EOPs) are among the biggest contributors to this burden. Herein we reviewed literature published for the period 2000e2023 on selected LOPs and EOPs in indoor dust and outdoor air in Africa to understand the occurrence, associated human health risks and common analytical techniques used to identify and quantify these contaminants. The findings revealed generally lower contamination levels for most pollutants than that in most regions outside Africa except for PCBs in outdoor air and OCPs in indoor settled dust. Apart from a few studies for polychlorinated biphenyls (PCBs), most studies reported hazard index (HI) values less than 1 for outdoor air and indoor dust exposure, which suggested negligible non-carcinogenic risks in children and adults. Gas Chromatography and mass spectrometry were the most frequently used analytical techniques for both air and dust probably due to their sensitivity and selectivity in detecting chemical traces at the pg m 3 and ng g 1 levels. Although the current contamination levels are generally low, their synergistic and cumulative effects may in the long run affect the environment and human health. There is also a paucity of data on most contaminants, especially for PCNs, and PFASs in both outdoor air and dust. Coordinated efforts are needed to limit the trade, importation, and disposal of products containing LOPs and EOPs in Africa.Item Novel and legacy per- and poly-fluoroalkyl substances in major wastewater treatment plants within the Lake Victoria basin, East Africa.(Elsevier B.V., 2025) Miiro, Ashirafu; Mubiru, Edward; Odume, Oghenekaro Nelson; Odongo, Silver; Nyakairu, George William; Matovu, Henry; Kato, Charles Drago; Spanik, Ivan; Sillanpää, Mika; Sifuna, Douglas; Khvalbota, Liudmyla; Ssebugere, PatrickOver the past two decades, rapid urbanization and industrialization in Uganda have generated wastewater containing emerging contaminants including per- and poly-fluoroalkyl substances (PFASs). This study assessed PFASs contamination of wastewater from Bugolobi (Kampala) and Kirinya (Jinja) wastewater treatment plants (WWTPs) by analyzing 80 influent and effluent samples for 15 PFASs using LC-MS/MS. We quantified 10 PFASs, with levels ranging from non-detectable (n.d) up to 372.4 ng/L (mean: 20.94 ± 0.42 ng/L). At Bugolobi WWTP, influent levels ranged from n.d to 190.01 ng/L (60.85 ± 1.03 ng/L) while effluents varied from n.d to 372.4 ng/L (237.91 ± 7.06 ng/L). At Kirinya WWTP, influent levels ranged from n.d to 29.37 ng/L (17.58 ± 3.54 ng/L) and effluents up to 30.21 ng/L (7.79 ± 0.85 ng/L). Short-chain PFASs (PFBS, PFBA) were more predominant, suggesting their possible use or degradation of the long-chain PFASs. Total mass loadings were higher at Bugolobi WWTP (5353.56 mg/day), serving the more densely populated Kampala, than at Kirinya WWTP (93.62 mg/day). PFSAs exhibited higher removal (72.45 % Bugolobi; 36.45 % Kirinya) than PFCAs (− 127.38 % Bugolobi; − 20.50 % Kirinya), which could be attributed to their stronger hydrophobic adsorption and partial biodegradation. Bugolobi, with ⁓82.59 % total removal, outperformed Kirinya (~25.19 %) due to its advanced conventional treatment. Ecological risk assessment revealed higher risks at lower trophic levels at Bugolobi compared to Kirinya, likely due to lower influx and partial mitigation by its pond-based system. These findings highlight the role of WWTPs as critical point sources of PFASs, posing ecological risks to aquatic ecosystems. Keywords: Per- and poly-fluoroalkyl substances, Wastewater treatment plants, Mass loadings, Ecological risks, Lake victoriaItem Organochlorine pesticides in placenta, blood and breast milk of mothers in Uganda : concentrations and health risks to breast fed infants.(Elsevier Ltd., 2026) Omoding, Daniel; Nantume, Teddy; Wasswa, John; Odongo, Silver; Kyarimpa, Christine; Karume, Ibrahim; Matovu, Henry; Sillanpa¨a¨, Mika; Kato, Charles Drago; Nabuuma, Josephine; Miiro, Ashirafu; Ssebugere, PatrickExposure to organochlorine pesticides (OCPs) remains a major public health concern in low-income countries, where historical usage and poor regulation continue to result in maternal and early-life exposures. This study assessed concentration profiles of selected OCPs, namely; p,p′-DDT, p,p′-DDE, o,p′-DDE, p,p′-DDD, o,p′-DDD, aldrin, dieldrin, lindane, α-endosulfan, β-endosulfan, and endosulfan-sulfate in maternal blood, breast milk, and placenta samples collected from 52 healthy mothers residing in the rural Kanungu District and urban Kampala District in Uganda. Analytical quantification was performed using gas chromatography-electron capture detection (GC-ECD), and compound identity was confirmed by gas chromatography–mass spectrometry (GC-MS). Concentrations of total DDTs (∑DDTs) were 63.0, 27.1, and 35.0 ng g-1 lipid weight (l.w) in blood, breast milk, and placenta, respectively. o,p′-DDE was the predominant metabolite in blood (67% of ∑DDTs), while p,p′-DDE dominated in placenta and milk (34% and 70%, respectively), possibly due to degradation of technical DDT applied in past decades. Other OCPs were generally low (Item Students’ perceptions of physical magnetic models and immersive virtual reality for chemistry learning.(Taylor & Francis, 2025) Ungu, Dewi Ayu Kencana; Won, Mihye; Matovu, Henry; Hernandez-Alvarado, Ricardo Bruno; Treagust, David F.; Mocerino, Mauro; Tasker, Roy; Tsai, Chin-ChungPhysical magnetic models and immersive virtual reality (iVR) both support students’ grasp of abstract chemistry concepts, yet the distinct affordances of each remain underexplored. In this qualitative study, forty undergraduate chemistry students (twenty pairs) completed learning activities on hydrogen bonds using both magnetic models and iVR. Pre/post semi-structured interviews were transcribed and analysed using a cross-case thematic analysis, beginning with inductive coding and followed by deductive mapping to existing literature. Four themes emerged – visualisation, interactivity, narrative (task design), and social features – highlighting the features of magnetic models and iVR that shape students’ learning experiences. Students reported that the magnetic model activity supported tactile exploration that helped them understand basic molecular concepts like attraction and repulsion. While it offers opportunities to test hypotheses, the magnetic model activity felt individualistic. In contrast, students saw iVR as a collaborative environment where complex tasks, advanced 3D visualisation, and interactivity deepened their understanding of hydrogen bonds. These findings highlight students’ distinct perceptions of each tool – magnetic models are effective for tactile, individual explorations, and iVR is valuable for collaboration, problem-solving, and visualising complex structures. Educators should leverage these differing affordances when designing learning experiences to support students’ understanding of scientific concepts. KEYWORDS: Immersive virtual reality (iVR), students’ perceptions, molecular visualization, physical molecular models