Journal Articles

Permanent URI for this collectionhttp://localhost:4000/handle/20.500.12504/98

Browse

Now showing 1 - 20 of 43

Legacy and emerging organic pollutants in indoor and outdoor environments in Africa: Contamination levels, health risks, and analytical techniques
(ScienceDirect, 2025-01-02) Godfrey, Muhwezi; Christine Kyarimpa; Christine Betty Nagawa; Solomon Omwoma; Henry Matovu; Julius Matsiko; Silver Odongo; Douglas Sifuna; Ivan Spanik; Charles Drago Kato; Patrick Ssebugere
The 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 m3 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. ©2025 The Authors. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license
Antibacterial properties of phytochemicals isolated from leaves of alstonia boonei and aerial parts of ipomoea cairica
(Natural Product Communications, 2024-09-26) Gumula, Ivan; Kyarimpa, Christine; Nanyonga, Sarah Kiwanuka; Kwesiga, George; Busulwa, George; Opio, Boniface; Heydenreich, Mathias; Omara, Timothy
Objective: The leaves of Alstonia boonei and aerial parts of Ipomoea cairica are used for treatment of microbial infections among other ailments in African traditional medicine. The aim of this study was to investigate the antimicrobial phytochemicals in A. boonei leaves and Ipomoea cairica aerial parts to validate their traditional use in Ugandan herbal medicine. Methods: The plant materials were separately extracted using a dichloromethane/methanol (1:1) solvent system and subjected to repeated chromatographic separation to isolate pure compounds. The chemical structures of the isolated compounds were determined through 1H NMR, 13C NMR and 2D NMR(COSY, HSQC and HMBC). The antibacterial activity of the extracts and pure compounds were assessed using the agar well diffusion method. Results: Chromatographic fractionation of the extracts yielded trans-fagaramide and a pentacyclic lupane-type triterpenoid, lupeol, from A. boonei, and friedelin from I. cairica. Trans-fagaramide was identified for the first time in the Alstonia genus while friedelin was identified for the first time in I. cairica. The isolated compounds demonstrated antibacterial activity, with trans-fagaramide showing a minimum inhibitory concentration (MIC) of 125 μg/mL against Pseudomonas aeruginosa and 250 μg/mL against Staphylococcus aureus, Salmonella typhi and Escherichia coli. Friedelin exhibited a MIC of 125 μg/mL against Escherichia coli and 250 μg/mL against Pseudomonas aeruginosa, Staphylococcus aureus and Salmonella typhi. Conclusion: The antibacterial activities observed in this study support the traditional use of A. boonei and I. cairica by indigenous communities in Uganda for treating microbial infections.
Safety, toxicological and allergenic aspects of using algae for food
(Springer Link, 2024-07-14) Kyarimpa, Christine; Omute, Tom; Nakiguli, Caroline K.; Khanakwa, Alice V.; Angiro, Christopher; Kahwa, Ivan; Ahumuza, Fortunate; Omara, Timothy
Consumption of algae has been historically practiced, especially in East Asia and the Pacific region cultures. However, sporadic events and empirical studies have suggested that some compounds could be triggering intoxications, allergic reactions and mortalities in humans who consumed algae. This chapter is an effort to explore with in-depth attention the safety, toxicological and allergic reactions following human consumption of algae. Based on retrieved literature, it is clear that toxicities and allergies from ingestion of algae are not a rarity, and to date, at least seventy (70) illnesses, six (6) allergic reactions and fourteen (14) mortalities have been reported globally. Toxicities and mortalities from intake of edible algae has been reported in species of Gracilaria, Caulerpa and Acanthophora genus, and are associated with their bioaccumulation of contaminants such as excess iodine, heavy metals, cyanotoxins or toxic inherent compounds such as caulerpenyne, manauealides A and C, prostaglandin E2, polycavernosides, aplysiatoxins and their derivatives. Allergenicity has been reported in Arthrospira, Chlorella, Chondrus, Eucheuma, Gigartina and Palmaria species, with the sulfated polysaccharide (carrageenan) and the photosynthetic pigment (C-phycocyanin) being the implicated allergens. These allergic reactions are mediated through activation of innate immune pathways of inflammation that trigger NF-kB activation, modification of gut microbiota and thickness of mucus barrier. We contend that appropriate labelling of algae-derived food products, public education, proper cleaning of fresh algae before consumption and profiling of toxic and allergenic algal species and compounds could aid in reducing intoxications and allergic reactions from algae used in food and food products. Future studies should consider examining edible algae for contaminants of emerging concern such as microplastics, cyanotoxins, emerging per- and polyfluoroalkyl substances, pharmaceutical residues and personal care products.
Role of starch in one pot fabrication of mesoporous gamma-alumina with excellent fluoride sorption capacity
(Sustainable Chemistry for the Environment, 2023-09-23) Ojok, Walter; Moodley, Brenda; Wasswa, John; Ntambi, Emmanuel; Wanasolo, William; Bolender, James
Green synthesis of mesoporous γ-AƖ2O3, a cutting-edge material for sustainable application in medicine, engineering, energy, and water treatment, is still challenging. Our study used a one-pot strategy for facile synthesis of γ-AƖ2O3 by sol-gel method using starch from cassava waste. AƖ(OH)3 were bound to the O-H groups of the starch molecule to form the AƖ(OH)3-starch complex in a nano-network confined in starch polymer cages. Its calcination at 500 ℃ produced a mesoporous, highly crystalline water stable γ-AƖ2O3 with a pore size of 2.07 nm and an extensive BET surface area (215 cm2/g). Using the response surface methodology (RSM), the as-synthesized γ-AƖ2O3 was optimized for efficient fluoride removal from water. A central composite design (CCD) was used to study the effect of initial fluoride concentration, pH, contact time, and sorbent dose on fluoride removal efficiency and optimization of the process. The relative importance of the sorption process variables to the fluoride removal process was assessed using ANOVA. The quadratic model showed that the predicted response was significantly correlated with the experimental response (R2 = 0.9667), with sorbent dose and pH being the process's most influential factors. Optimum conditions for 93.6% fluoride removal efficiency were sorbent dose of 0.5 g, initial fluoride concentration of 10 mg/L, pH 7, and contact time of 137.5 min. A weakly acidic medium favored fluoride removal from water, while the presence of PO43- and HCO3- retarded the process. The sorption data fitted well in the Langmuir isotherm (0.9783) and pseudo-second-order kinetic model (0.9999), indicative of a chemisorption process. The maximum sorption capacity towards fluoride was 207.5 mg/g. A thermodynamic study indicated that the sorption process was spontaneous and endothermic, with increased randomness at the solid-solution interface. Sorption, desorption, sustainability, and leaching tests showed that the sorbent could be used for sustainable fluoride removal at 8.3 USD/1000 liters of safe drinking water.
Sorption mechanisms and enhancement of selected organochlorine pollutants in water on zeolites
(Journal of Chemistry, 2024-01) Timothy, Manda; Solomon, Omwoma; Godfrey, Okumu Barasa; Anthony, M. Pembere; Douglas, Sifuna; Livingstone, Ochilo; Silas, Lagat; Emily, Ngeno; Patrick, Ssebugere; Christine, Betty Nagawa; Christine, Kyarimpa
Tis study investigates the adsorption capacities of selected organochlorines on zeolites, focusing on hexachlorobenzene (HCB), hexachlorotetradecane (HCTD), hexachlorodecane (HCD), hexachlorocyclohexane (HCH), heptachlorodecane (HPCD), octachlorodecane (OCD), dichlorodiphenyltrichloroethane (DDT), and octachlorotetradecane (OCTD). Te structures of the organochlorines were optimized and their Frontier molecular orbitals were calculated. Te analysis of HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) energies provided insights into the molecules’ electron-donating and -accepting capabilities. Te present research identifed the universal force feld as suitable for the investigation and used it to evaluate the adsorption capacities of the pollutants on various zeolites. It was found that CLO (a cubic microporous gallophosphate) demonstrated the highest adsorption capacity for HCB among 245 zeolites, with a loading capacity of 65.84 wt%. In terms of molecules adsorbed per cell, CLO remained the highest with 120 molecules per cell for HCB, 113 molecules per cell for HCH, 43 molecules per cell for DDT, 21 molecules per cell for HCTD, 19 molecules per cell for OCTD, 47 molecules per cell for HCD, 30 molecules per cell for HPCD, and 22 molecules per cell for OCD. Te analysis revealed correlations between the structural parameters of zeolites (mass, density, HVF, APV, VSA, GSA, DPS, and Di) and their adsorption capacities. Te investigation delved into cluster models to understand the interaction of organochlorines with the zeolite framework. Te study explored the impact of doping CLO zeolite with diferent atoms (Al, Si, and Na) on adsorption capacity. Te results showed that doping with aluminum improved both loading capacity and adsorption energy and dissociate the chlorinated compounds during adsorption. Quantum chemical calculations show that hydrogen-based bonding of the organochlorides on the CLO is thermodynamically favorable compared to dissociative adsorption. In addition, oxygen atoms in the zeolites provide active adsorption sites. In the present work, laboratory adsorption experiments were performed, treating zeolites with heat at 400 °C. Surprisingly, untreated zeolites outperformed treated ones, adsorbing up to 91% of HCB, while treated zeolites reached saturation after the third run. Te study attributed the better performance of untreated zeolites to the presence of interstitial water and hydrogen atoms, which are critical for electrostatic interactions with organic compounds. In general, this research provides a comprehensive analysis of the adsorption capacities of organochlorines on zeolites, combining computational simulations and laboratory experiments. Tis work’s distinctive quality is its methodology that combines molecular simulations, experimental verifcation, doping, and interstitial water efects. Te fndings emphasize the importance of zeolite (a high-porosity nanostructured material) structure, composition, and treatment methods in determining their efectiveness as adsorbents for environmental pollutants.
Aflatoxins in Uganda: an encyclopedic review of the etiology, epidemiology, detection, quantification, exposure assessment, reduction, and control
(International Journal of Microbiology, 2020-01-08) Timothy, Omara; Winfred, Nassazi; Tom, Omute; Aburu, Awath; Fortunate, Laker; Raymond, Kalukusu; Bashir, Musau; Brenda, Victoria Nakabuye; Sarah, Kagoya; George, Otim; Eddie, Adupa
Uganda is an agrarian country where farming employs more than 60% of the population. Aflatoxins remain a scourge in the country, unprecedentedly reducing the nutritional and economic value of agricultural foods. This review was sought to synthetize the country’s major findings in relation to the mycotoxins’ etiology, epidemiology, detection, quantification, exposure assessment, control, and reduction in different matrices. Electronic results indicate that aflatoxins in Uganda are produced by Aspergillus flavus and A. parasiticus and have been reported in maize, sorghum, sesame, beans, sunflower, millet, peanuts, and cassava. The causes and proliferation of aflatoxigenic contamination of Ugandan foods have been largely due to poor pre-, peri-, and postharvest activities, poor government legislation, lack of awareness, and low levels of education among farmers, entrepreneurs, and consumers on this plague. Little diet diversity has exacerbated the risk of exposure to aflatoxins in Uganda because most of the staple foods are aflatoxin-prone. On the detection and control, these are still marginal, though some devoted scholars have devised and validated a sensitive portable device for on-site aflatoxin detection in maize and shown that starter cultures used for making some cereal-based beverages have the potential to bind aflatoxins. More efforts should be geared towards awareness creation and vaccination against hepatitis B and hepatitis A to reduce the risk of development of liver cancer among the populace.
Lacustrine cyanobacteria, algal blooms and cyanotoxins in east Africa: implications for human and ecological health protection
(Phycology, 2023-02) Timothy, Omara; Christine, Betty Nagawa; Christine, Kyarimpa; Stefan, Böhmdorfer; Thomas, Rosenau; Solomon, Omwoma Lugasi; Henry, Matovu; Silver, Odongo; Patrick, Ssebugere
Advected cyanobacteria, algal blooms and cyanotoxins have been increasingly detected in freshwater ecosystems. This review gives an insight into the present state of knowledge on the taxonomy, dynamics, toxic effects, human and ecological health implications of cyanobacteria, algal blooms and cyanotoxins in the East African Community lakes. The major toxigenic microalgae in East African lakes include Microcystis, Arthrospira, Dolichospermum, Planktolyngbya and Anabaenopsis species. Anatoxin-a, homoanatoxin-a, microcystins (MCs), cylindrospermopsin and nodularin have been quantified in water from below method detection limits to 81 μg L−1, with peak concentrations characteristically reported for the wet season. In whole fish, gut, liver and muscles, MCs have been found at concentrations of 2.4 to 1479.24 μg kg−1, which can pose human health risks to a daily consumer. While there have been no reported cases of cyanotoxin-related poisoning in humans, MCs and anatoxin-a (up to 0.0514 μg kg−1) have been identified as the proximal cause of indiscriminate fish kills and epornitic mortality of algivorous Phoeniconaias minor (lesser flamingos). With the unequivocal increase in climate change and variability, algal blooms and cyanotoxins will increase in frequency and severity, and this will necessitate swift action towards the mitigation of nutrient-rich pollutants loading into lakes in the region.
Physicochemical quality of water and health risks associated with consumption of African lung fish (Protopterus annectens) from Nyabarongo and Nyabugogo rivers, Rwanda
(BMC research notes, 2020) Timothy, Omara; Papias, Nteziyaremye; Solomon, Akaganyira; Dickens, Waswa Opio; Lucy, Nyambura Karanja; Decrah, Moraa Nyangena; Betty, Jematia Kiptui; Remish, Ogwang; Stephen, Mark Epiaka; Abigael, Jepchirchir; Alfayo, Maiyo
Objective: To determine the quality of water, heavy metal content of edible muscles of a piscivorous fish (Protopterus annectens) and assess the health risks associated with using water and consumption of P. annectens from Nyabarongo and Nyabugogo rivers of Rwanda. Results: All the water quality parameters were within World Health Organization’s acceptable limits except total nitrogen, iron, manganese and lead levels. Edible muscles of Protopterus annectens contained 272.8 ± 0.36, 292.2 ± 0.25, 8.8 ± 0.36, 135.2 ± 0.15, 148.0 ± 0.21 and 432. 0 ± 0.50 mg/kg of iron, manganese, copper, zinc, chromium and lead at Ruliba station and 336.0 ± 0.70, 302.6 ± 1.22, 6.4 ± 0.26, 44.7 ± 0.20, 138.2 ± 0.17 and 302.4 ± 1.50 mg/kg of iron, manganese, copper, zinc, chromium and lead at Kirinda bridge of Nyabarongo river. Health risk assessments indi‑ cated that though ingestion and dermal contact with heavy metals in water from the rivers may not cause obvious health effects, consumption of Protopterus annectens from Nyabarongo river may lead to deleterious health effects.
Effects of industrial effluents on the quality of water in Namanve stream, Kampala Industrial and Business Park, Uganda
(BMC Research Notes, 2020) Christopher, Angiro; Patrick, P’Odyek Abila; Timothy, Omara
Objective: Kampala Industrial and Business Park (KIBP) is one of the premier and the most successful Ugandan indus‑ trial complexes that impact the inner Murchison bay of Lake Victoria. The current study aimed at evaluating the effect of industrial effluents on the physicochemical and microbiological quality of water taken from four different sites along Namanve stream in KIBP, Wakiso district, Uganda. Results: All the water quality parameters were below WHO maximum permissible limits except turbidity, electrical conductivity and Escherichia coli count. Mean values of the monitored water quality parameters increased from the point of effluent discharge downstream of Namanve stream.
Heavy metal contamination of sediments from an exoreic African great lakes’ shores (Port bell, Lake Victoria), Uganda
(Pollutants, 2022-09-27) Gabson, Baguma; Andrew, Musasizi; Hannington, Twinomuhwezi; Allan, Gonzaga; Caroline, K. Nakiguli; Patrick, Onen; Christopher, Angiro; Augastine, Okwir; Boniface, Opio; Thomas, Otema; Daniel, Ocira; Ivan, Byaruhanga; Eric, Nirigiyimana; Timothy, Omara
Lake Victoria (L. Victoria) is the largest African tropical and freshwater lake, with one of the highest pollution levels, globally. It is shared among Uganda, Kenya and Tanzania, but it is drained only by the river Nile, the longest river in Africa. Though environmental studies have been conducted in the lake, investigations of the heavy metals (HMs) contamination of sediments from fish landing sites and ports on the Ugandan portion of L. Victoria are limited. In this study, sediments of an urban, industrial and fish landing site (Port Bell) on L. Victoria, Uganda was investigated to establish its HMs pollution levels and potential health risks to humans and ecosystems. Sediment samples were collected in triplicate (n = 9) from three different points of Port Bell, digested and analyzed using atomic absorption spectrometry for the presence of these HMs: copper (Cu), lead (Pb), cadmium (Cd) and chromium (Cr). The average daily dose through dermal contact and hazard quotient (HQ) were calculated to assess the health risk that is associated with dredging works (lake sand mining). Four geochemical enrichment indices: contamination factor (CF), geo-accumulation index (Igeo), pollution load index (PLI) and potential ecological risk (PERI) were used to quantify the contamination of the HMs in the sediments. The results showed that the mean HM content of the samples ranged from: 6.111 ± 0.01 to 7.111 ± 0.002 mg/kg for Cu; from 40.222 ± 0.003 to 44.212 ± 0.002 mg/kg for Pb; from 0.352 ± 0.007 to 0.522 ± 0.010 mg/kg for Cr; from 3.002 ± 0.002 to 3.453 ± 0.003 mg/kg for Cd. Health risk assessments indicated that there are no discernible non-carcinogenic health risks that could arise from the dredging works that are conducted in the study area as the indices were all below one. The contamination factors that were obtained suggest that Cd has reached a state of severe enrichment in the sediments (CF > 6). An assessment using Igeo established that the sediments were not contaminated with regards to Cu and Cr, but they exhibited low-to-median and median contamination with respect to Pb and Cd, respectively. Though the pollution load indices show that the contamination levels raise no serious concerns, the potential ecological risk indices show that there is considerable pollution of the Port Bell sediments, particularly with regard to Cd. Upon examination using multivariate statistical analyses, Cd and Cr showed a strong correlation which alluded to their introduction from anthropogenic sources. Based on the sedimentary HMs concentrations and the environmental indices that are employed in this study, it is recommended that the spatial variations in the concentrations of the HMs in water, sediments and biota should be monitored.
Compliance and implementation of municipal solid waste management laws and regulations in Mukono district, Uganda
(Archives of Current Research International, 2023-09) Dan, Kibuuka Kiguli; Ameria, Nabukonde; Alex, Barakagira
Consumption and production of resources leads to generation of wastes that may be undesirable in the environment. Solid waste management laws are put in place aimed at ensuring proper and effective control and management of wastes in an area. This study was set out to assess the compliance and implementation of municipal solid waste management laws and regulations in Mukono district, Uganda. Specifically, the study sought to: characterize the solid wastes generated in Mukono municipality; determine the mechanisms of implementation of solid waste management laws and regulations in Mukono municipality; and to assess the effectiveness of the solid waste management laws and regulations in Mukono municipality. A case study design complimented with both quantitative and qualitative approaches were employed to obtain the required data to answer the stated objectives. A questionnaire and documentary review were used to collect the required data for the study. A number of solid wastes including food and food wastes; glass, plastics and metals; and textiles among others were generated in Mukono municipality. There are solid waste management laws and regulations used in the management of wastes in Mukono municipality. Some mechanisms including awareness creation and monitoring implementation processes have been put in place for an effective implementation of municipal solid waste management laws. The study found out that there has been an ineffective implementation of municipal solid waste management laws in Mukono municipality which were most likely brought about by poor leadership, inappropriate allocation of funds and low levels of awareness among members of the local community. It is recommended that Institutions like the Environment Police and the National Environment Authority should work hand in hand to strengthen the implementation of solid waste management laws and regulations in the country. The government should enhance sensitization campaigns about what the solid waste management laws and regulations entail. In addition, funds required for implementation of the laws and regulations should be appropriated and be used for the intended purposes.
Medicinal plants used in the management of sexual dysfunction, infertility and improving virility in the east African community: a systematic review
(Evidence-Based Complementary and Alternative Medicine, 2023-08) Christine, Kyarimpa; Christine, Betty Nagawa; Timothy, Omara; Silver, Odongo; Patrick, Ssebugere; Solomon, Omwoma Lugasi; Ivan, Gumula
Sexual disorders such as erectile dysfunction (ED), sterility, and sexual inappetence represent some of the complex reproductive challenges that require addressing the underlying causes. Te aim of this paper was to systematically synthesize literature on the ethnobotany, phytochemistry, bioactivities, and safety of plants used as remedies for managing sexual dysfunction and infertility, and improving fertility and virility in the EAC. Trough an extensive review conducted in multidisciplinary electronic databases, 171 plant species were identifed to have been reported for the management of sexual inappetence (i.e., used as aphrodisiacs, 39.4%), ED (35.9%), infertility (18.7%), and increasing fertility (6.0%). Te most used plants are Mondia whitei, Acalypha villicaulis, Combretum illairii, Erythrina abyssinica, Pappea capensis, Rhus vulgaris, and Warburgia ugandensis while roots (44.9%), leaves (21.8%), stem and root barks (16.7%) of shrubs (35%), trees (31%), herbs (26%), and climbers (8%) are the preferred organs for making decoctions (69%). Te research strides to date indicate that Citropsis articulata, Cola acuminata, Ekebergia capensis, Plumbago zeylanica, Tarenna graveolens, Urtica massaica, and Zingiber ofcinale have been assessed for their bioactivity. Te majority (71.4%) of the plants either increased testosterone levels and mounting frequency or elicited prosexual stimulatory efects in male rats. More studies investigating the relevant pharmacological activities (aphrodisiac, fertility, and phosphodiesterase-5 inhibitory activities), safety aspects, responsible compounds, and clinical studies are warranted to establish the pharmacological potential of the unstudied species and elucidate the mechanism of action of the bioactive compounds.
Antibacterial and anticancer activities of green-synthesized silver nanoparticles using Photinia glabra fruit extract
(Nanomedicine, 2023-08) Tabbisa, Namulinda; Lei-Lei, Bao; Justus, Kwetegyeka; Ivan, Gumula; Yi-Jia, Yan; Zhi-Long, Chen
Aims: We prepared Photinia glabra (PG) aqueous fruit extract, utilized it to synthesize silver nanoparticles (PG-Ag NPs) and evaluated the antibacterial and anticancer activities of the nanoparticles (NPs). Materials & methods: Silver nitrate aqueous solution was reduced to PG-Ag NPs using aqueous PG fruit extract. NP shape, size, composition and functionalization were determined using transmission electron microscopy, x-ray photoelectron spectroscopy, Fourier transform infrared and x-ray diffraction. Results & conclusions: PG-Ag NPs were spherical, approximately 39–77 nm-sized, functionalized surfaces with notable antibacterial activity against both Escherichia coli and Staphylococcus aureus, with an MIC <30 ug/ml and cytotoxicity toward esophageal cancer cells, with IC50 values less than 20 ug/ml. PG-Ag@rt NPs have been shown to be a potent antibacterial and anticancer agent, and their enriched particle surfaces can be conjugated with other compounds for multibiomedical applications.
Phytochemical-based evidence of the health benefits of bidens pilosa extracts and cytotoxicity
(Chemistry Africa, 2023-03) Oladayo, Amed Idris; Nasifu, Kerebba; Suranie, Horn; Mark Steve, Maboeta; Rialet, Pieters
Purpose Bidens pilosa L. is traditionally used as a flavouring agent in foods, in the treatment of diseases, in agriculture as a biopesticide and herbicide, and in the phytoremediation of soils contaminated with heavy metals. The vast range of uses of B. pilosa for a variety of purposes is questionable, hence motivating the objectives of this study, which are to assess the cytotoxicity, health benefits, and/or risks of B. pilosa using chemical-based evidence. Methods A real-time cell analysis (xCELLigence system), ultra-high-performance liquid chromatography coupled to a quadrupole-time-of-flight mass spectrometer, high-performance liquid chromatography with a diode array detector, and chemical-based spectrophotometric methods were adopted in the study. Results High concentrations of the ethanol extracts exhibited cytotoxic activity on HepG2 (cancerous), and Vero (non-can- cerous) cell lines, whereas the water extracts promoted cell proliferation at selected concentrations. The chemical profiling enabled the separation as well as characterisation of 137 phytochemicals. These were mainly phenolic acids, flavonoids, fatty acids, coumarins, and furanocoumarins. There was no toxic compound identified. Conclusion The ethanol extracts are generally more potent and exhibit stronger antioxidant activity and cytotoxicity, prob- ably due to the presence of more flavonoids and phenolic acids, validating the uses of B. pilosa and its relevance as a source of functional phytochemicals.
Green practices implementation for environmental sustainability by five‑star hotels in Kampala, Uganda
(SpringerLink, 2023-03) Alex, Barakagira; Christopher, Paapa
Hotels operate continuously and are known to be one of the contributors of global pollution. Strategies like adoption of green practices would be a remedy to mitigate pollution and their effects for environmental sustainability. This study focused on green practice’s implementation by the five-star hotels in Kampala district, Uganda. Specifically, it explored the benefits achieved and effects encountered by the management of the hotels as a result of implementing green practices. A questionnaire survey and interviews were employed to collect the required data from the employees of the five-star hotels. Energy conservation, waste management, and environmental purchasing with their respective coefficient of variances of 12.6, 14.5 and 17.2 were some of the green practices implemented by the hotels. Green practice’s adoption by the five-star hotels culminated into increased profits, competitive advantage, saved on the costs of the materials used and retained some customers. The study recommends that there should be continuous awareness and strengthening of training of the employees about green practices’ implementation, together with government involvement in all matters concerning enforcement of green practices. In addition, the article suggests managerial implications and opportunities for future research.
Watershed management and climate change adaptation mechanisms used by people living in dryland areas of Lokere catchment in Karamoja, Uganda
(Environmental & Socio-economic Studies, 2023-04) Alex, Barakagira; Isaiah, Ndungo
The effects of climate change in Uganda are manifested by severe and sometimes extreme weather events such as droughts and landslides. An Integrated Watershed Management (IWM) plan was initiated in the Karamoja region, aimed at generating information that could be used to reduce climate vulnerabilities among the rural poor. The study aimed at determining the local community’s perception of the effects of climate change on their livelihoods; and, to examine the effectiveness of the Integrated Watershed Management practices (IWMPs) on agricultural production within the area. Three hundred and ninety-seven households were randomly chosen and included in the survey. Interviews with local government officials who held high posts were conducted. Direct observations were also used for data collection. Findings showed that droughts and increases in pests and diseases; were some of the impacts caused by climate change events. Despite the initiation of IWMPs, climate change events moderately increased food insecurity (γ = 0.556; P=0.000) and also moderately affected community assets like roads and valley dams (γ = 0.426; P=0.000). In addition, household income insecurity was moderately and positively related to climate change effects (γ = 0.556; P=0.000). A weak positive relationship was found between the application of IWMPs and agricultural production (γ = 0.273; P=0.000). The Uganda Government should emphasize and intensify the implementation of IWMPs among the farmers living in agricultural watersheds as a means of continuously improving agricultural production and building the farmers’ resilience to climate change events.
Speciation of heavy metals in water from the Uganda side of Lake Victoria
(International Journal of Environmental Studies, 2010-02) Jolocam, Mbabazi; H., Twinomuhwezi; J., Wasswa; M., Ntale; G., Mulongo; J., Kwetegyeka; K.H., SchrǾder
Different forms of copper Cu, zinc Zn, lead Pb and cadmium Cd in water from the Uganda side ofLake Victoria (25°C, pH 6.75–7.18), the second largest inland freshwater lake in the world, havebeen studied using ion-exchange, dialysis and atomic absorption spectrophotometry. The resultsindicate that heavy metals Cu, Zn, Pb and Cd are present mainly in the cationic form (80–83%).Small quantities of anionic (13–22%), non-ionic, dialyzable (4–8%), and non-ionic, non-dialyzable(< 1.3–4.4%) forms were also detected for all metals except Cd. The corresponding concentrationslay in the ranges: cationic, 0.06–0.99; anionic, < 0.001–0.25; non-ionic, dialyzable, < 0.001–0.08;non-ionic, non-dialyzable, < 0.001–0.06 μg ml−1. The existence of the metals in non-ionic and non-dialyzable forms is attributable to metal associations with high relative molecular mass (RMM)organic matters.
Concentrations and sources apportionment of polycyclic aromatic hydrocarbons in sediments from the Uganda side of Lake Victoria
(Environmental Science: Processes & Impacts, 2017) Nasifu, Kerebba; Patrick, Ssebugere; Justus, Kwetegyeka; Kenneth, Arinaitwea; John, Wasswa
This study presents the levels and possible sources of selected polycyclic aromatic hydrocarbons (PAHs) in surface sediments from the Napoleon Gulf and Murchison Bay of Lake Victoria. Sediment samples were extracted and cleaned up for PAHs using UNEP, 1992, and EPA method 3630C protocols. The analysis of sample extracts was carried out using a gas chromatograph coupled to a mass spectrometer. Fifteen congeners, mostly the high molecular weight PAHs (HPAHs) (4–6 rings) were detected. Total (∑) concentrations varied from 44.2 to 80.2 ng g−1 dry weight (d.w.) at the Napoleon Gulf, while those at the Murchison Bay ranged from 17.0 to 55.0 ng g−1 d.w. Statistical analysis showed no significant difference in the concentrations of PAHs among sites (p < 0.05, ANOVA). It was noted that the concentrations for most sampling sites were far below the lowest effect levels based on the Sediment Quality Guidelines, except for one station at the Napoleon Gulf. Principal component analysis and diagnostic ratios indicated that PAHs of combustion and petroleum origin were dominant and brought about mainly by atmospheric deposition.
Organochlorine pesticide residues in Uganda’s honey as a bioindicator of environmental contamination and reproductive health implications to consumers
(Elsevier, 2021) Stuart Ben, Mukiibi; Steven Allan, Nyanzi; Justus, Kwetegyeka; Chijioke, Olisah; Adewale Matthew, Taiwo; Edward, Mubiru; Emmanuel, Tebandeke; Henry, Matovu; Silver, Odongo; Juma John Moses, Abayi; Emily Chelangat, Ngeno; Mika, Sillanp; Patrick, Ssebugere
Honey has multifaceted nutritional and medicinal values; however, its quality is hinged on the floral origin of the nectar. Taking advantage of the large areas that they cover; honeybees are often used as bioindicators of environmental contamination. The focus of the present paper was to examine the quality of honey from within the vicinity of an abandoned pesticide store in Masindi District in western Uganda. Surficial soils (< 20 cm depths) and honey samples were collected from within the vicinity of the abandoned pesticide store and analysed for organochlorine pesticide (OCP) residues using gas chromatograph coupled to an electron capture detector (GC-ECD). The mean level of ∑DDTs in all the soil samples was 503.6 µg/kg dry weight (d.w). ∑DDTs contributed 92.2% to the ∑OCPs contamination loads in the soil samples, and others (lindane, aldrin, dieldrin, and endosulfans) contributed only 7.8%. Ratio (p, p′-DDE + p, p′-DDD)/p, p′-DDT of 1.54 suggested historical DDT input in the area. In all the honey samples, the mean level of ∑DDTs was 20.9 µg/kg. ∑DDTs contributed 43.3% to ∑OCPs contamination loads in the honey samples, followed by lindane (29.8%), endosulfans (23.6%) and dieldrin (3.2%), with corresponding mean levels of 14.4, 11.4 and 1.55 µg/kg, respectively. Reproductive risk assessment was done based on the hazard quotient (HQ) and hazard index (HI) procedure. In our study, the calculated HIs for adults (102.38), and children (90.33) suggested high potential health risks to the honey consumers. Lindane, endosulfan and p, p′-DDD detected in the honey samples at levels exceeding the acute reference dose (ARfD) are known risk factors for spontaneous abortion, reduced implantation, menstrual cycle shortening, impaired semen quality, and prostate cancer in exposed individuals and experimental animal models.
Heavy metal contamination in vegetables cultivated on a major urban wetland inlet drainage system of Lake Victoria, Uganda
(International Journal of Environmental Studies, 2010-06) Jolocam, Mbabazi; J., Wasswa; J., Kwetegyeka; G.K., Bakyaita
The population of the Ugandan capital, Kampala, located close to Lake Victoria, appears to be exposed to risk of ingesting the heavy metals Cadmium (Cd) and Lead (Pb) through vegetables in their diet. Lake Victoria is responsible for frequent torrential polluted runoffs in the city. The Nakivubo channel, the city’s major wetland drainage system, empties directly into the lake. Vegetables are grown on the urban wetland soils. Heavy metal content in vegetables from the wetland cultivation sites was determined by wet acid digestion, with 87–92% recovery. The results showed that although the heavy metal levels of manganese (Mn), zinc (Zn), cadmium (Cd) and lead (Pb) were significantly higher than those in similar food crops from rural control sites, only Cd and Pb exceeded the World Health Organisation (WHO) maximum permissible levels. Cd and Pb pose serious human health risks. Early pollution control measures are advisable.

Browse

Recent Submissions