Potentially toxic element (PTE) contamination of food systems has emerged as an important environmental and public health concern in many developing countries, including Uganda, owing to rapid urbanization, industrialization, mining activities, wastewater reuse, informal waste disposal, and expanding urban agriculture. This review synthesizes evidence from peer-reviewed and selected grey literature on the occurrence of cadmium (Cd), chromium (Cr), nickel (Ni), lead (Pb), and arsenic (As) in cereals, vegetables, tubers, livestock products, fish, fruits, and processed foods consumed in Uganda. A structured literature synthesis and screening-level dietary risk assessment using estimated daily intake (EDI), target hazard quotient (THQ), hazard index (HI), carcinogenic risk (CR), and total carcinogenic risk (TCR) were conducted to identify contamination hotspots, priority exposure pathways, and potential public health implications. The available evidence revealed substantial spatial variability, with contamination consistently concentrated in mining-influenced agricultural areas, wastewater-irrigated farms, municipal dumpsites, industrial corridors, and urban food markets. Vegetables, cereals, livestock products, fish, and street-vended foods exhibited the greatest contamination burdens, while Pb and Cd were the PTEs most frequently reported exceeding WHO/FAO, Codex Alimentarius, and Ugandan food safety limits. Screening-level risk estimates indicated that Pb, Cd, and Cr contributed most to cumulative dietary exposure, with children consistently exhibiting higher EDI, THQ, HI, and TCR values than adults because of greater food intake relative to body weight. Although cumulative HI and TCR values exceeded recommended screening thresholds in several hotspot regions, these estimates should be interpreted as conservative screening-level indicators derived from heterogeneous published datasets rather than nationally representative measures of dietary exposure. Overall, the evidence indicates that PTE contamination in Ugandan food systems is predominantly hotspot-driven and highlights the need for targeted surveillance, standardized monitoring and reporting, improved pollution control, and strengthened food safety management to reduce chronic dietary exposure and protect public health.

Background: Zanthoxylum gilletii, an important African medicinal plant, is widely used in traditional medicine for treating various ailments due to its rich phytochemical composition. However, despite its extensive ethnomedicinal applications, the specific bioactive compounds responsible for its antimicrobial properties remain insufficiently characterized. Aims: The study aims to isolate and characterise bioactive compounds from Zanthoxylum gilletii stem bark and evaluate their antimicrobial activity against selected bacterial and fungal pathogens. Methodology: Zanthoxylum gilletii stem bark was collected from Mabira Forest Reserve (0°23′54″N 33°0′59″E), Buikwe District, Uganda on 17th June 2022. The experiments were performed at the Department of Chemistry, Kyambogo University, between June 2022 and July 2023. Stem barks were shade dried, powdered, and extracted using Maceration technique with a mixture of methanol and dichloromethane (ratio 1:1) solvent. The extract was subjected to open column chromatography and identified using NMR spectroscopy and compared with literature information. Antimicrobial activity of crude extract and also the isolated compounds were assessed via disk diffusion against five bacterial and two fungal strains. Results: In this study, four known compounds: lupeol (1), stigmasterol (2), α-amyrin cinnamate (3) and α-amyrin acetate (4) were isolated from stem bark extracts of Zanthoxylum gilletii. This is the first-time compound 4 is reported in Zanthoxylum genus. The compounds had antimicrobial activities against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Enterobacter cloacae, Candida albicans and Aspergillus fumigatus. The extract and the compounds displayed inhibition against the microorganisms with diameters measuring 3.0±0.0 mm to 19.0±0.0 mm. The minimal inhibitory concentrations (MICs and MFCs) for active strains ranged from 6.25 to 150 mg/mL. Conclusion: The observed activities support the traditional use of this plant in treating various ailments by Ugandan communities.

Traditional pyrotechnic composites (PCs), often synthesized with epoxy or other synthetic binders, can combust at temperatures up to 2100 °C, creating secondary fire and explosion risks. This study examines how renewable, cost-effective binders: starch, guar gum, tannic acid, and sodium carboxymethyl cellulose affect the combustion behavior, exothermicity, temperature profiles, and fire-suppression performance of PCs in a 4.57 kW n-heptane pool fire. Characterization of the aerosol particulates was performed using XRD, FTIR, and SEM. SEM-EDX and DSC for the PCs. PC-1, with a linear burning rate (LBR) of 10.05 ± 2.158 mm/s, extinguished the fire within 5 s and generated the highest ignition temperature (210 °C), whereas PC-4 and PC-5 with LBRs of 9.3 ± 0.742 mm/s and 9.7 ± 0.693 mm/s, respectively showed a noticeable decrease in ignition temperatures (184 °C and 182 °C, respectively) and suppressed the fire within 7 s and 5 s, respectively. It can be concluded that starch-based PC exhibited optimal fire performance parameters, making it a promising bio-based binder for the KNO₃-KClO₄-3, 5 DNB pyrotechnic composition.