Browsing by Author "Muhwezi, Godfrey"

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    Anthropogenic footprint and ecological risk assessment of organochlorine pesticides and polychlorinated biphenyls in sediments from Lake Victoria, East Africa
    (Elsevier, 2025-12-15) Kagoya, Afuwa; Arinaitwe, Kenneth; Odongo, Silver; Sifuna, Douglas; Matovu, Henry; Matsiko, Julius; Muhwezi, Godfrey; ˇSp´anik, Ivan; Kato, Charles Drago; Sillanpa, Mika; Ssebugere, Patrick
    Lake Victoria, the world’s second-largest freshwater lake, continues to face pressure from anthropogenic activities in its catchment area, releasing pollutants, which are ultimately trapped in the sediment core, thereby posing threats to aquatic organisms. This study quantified thirteen organochlorine pesticides (OCPs) and ten polychlorinated biphenyls (PCBs) in sediments from the Uganda, Kenya, and Tanzania sides of Lake Victoria using soxhlet method, fractionation column and GC–MS/MS analysis. Total (∑13) OCPs levels were up to 412, 148, and 522 µg kg-1 dry weight (d.w), and 12.1, 8.69 and 9.87 µg kg-1 dw for total (∑10) PCBs for sediments from Uganda, Kenya, and Tanzania, respectively. Diagnostic ratios suggested past and ongoing use of OCPs while principal component analysis confirmed that OCP profiles were mainly due to their application in controlling pests in agriculture and public health programs, and PCB congeners were largely due to volatilization, degradation of higher PCBs into lighter PCBs, improper waste disposal of old transformers, hydraulic fluids, plasticizers, and capacitors. Ecological risk assessment highlighted that the PCB levels in sediments were below threshold effect and probable effect levels, but p,p′-DDD, and lindane were likely to pose adverse effects to sediment-dwelling organisms in Lake Victoria. These results imply persistent pollutant loads in Lake Victoria, and consequently, a need for its enhanced management.
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    Assessment of Cadmium and Lead in dried sewage sludge from Lubigi feacal sludge and wastewater treatment plant in Uganda
    (Journal of Water Resource and Protection, 2019) Kyayesimira, Juliet; Ssemaganda, Abbey; Muhwezi, Godfrey; Andama, Morgan
    Sludge contains organic and inorganic compounds including traces of heavy metals such as lead (Pb), cadmium (Cd), copper (Cu), nickel (Ni), chromium (Cr) and others. These metals restrict the use of sludge in agriculture because their accumulation is harmful to the environment and particularly the food chain. Cadmium and lead are among the most common heavy metals found in municipal wastewater treatment plant sludge. They are capable of bioaccumulation in plant tissues like roots and leaves and are non-biodegradable and therefore they remain in the sludge which is disposed on land or used as fertilizers on farms. The presence of heavy metal pollutants serves as a great threat to soils and also makes plants grown on such soils unfit for animal and human consumption as they may have detrimental effects to animal and human life. For instance, Pb and Cd are known to be human carcinogens. This study therefore aimed to investigate the levels of Cd and Pb in the treated dry sludge from Lubigi Feacal Sludge and Wastewater treatment plant located in Kawempe division, Kampala city, Uganda so as to ascertain its safety for use on agricultural lands. Two batches of samples were collected and analyzed at Government Analytical laboratory in Wandegeya, Uganda. The acid digested sludge samples were analyzed using Atomic Absorption Spectroscopy (AAS) method. The average concentrations of Pb found in collected sludge samples, batch 1 (11.912 mg/kg dm) and batch 2 (5.304 mg/kg dm) were far below the Environment Protection Agency (EPA) maximum permissible concentration (840 mg/kg) for any land application. Cadmium was not detected in all the sludge samples collected; there is an implication that it is either completely absent in the sludge generated by the plant or present but far below detectable levels. The sludge generated from Lubigi fecal sludge and wastewater treatment plant is therefore safe for application on agricultural lands as far as Pb and Cd concentrations are concerned.
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    Legacy and emerging organic pollutants in indoor and outdoor environments in africa: contamination levels, health risks, and analytical techniques
    (Elsevier, 2025-01-02) Muhwezi, Godfrey; Kyarimpa, Christine; Gumula, Ivan; Nagawa, Christine Betty; Omwoma, Solomon; Matovu, Henry; Matsiko, Julius; Odongo, Silver; Sifuna, Douglas; Špánik, Ivan; Kato, Charles Drago; Ssebugere, Patrick
    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 2000-2023 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.
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    Quantification of fine particulate matter and carbon monoxide from households cooking with fixed mud charcoal stoves in Awindiri ward, Arua municipality, Uganda
    (Springer Nature, 2024-11-14) Muhwezi, Godfrey; Ruhangariyo, D.; Kyayesimira, J.; Andama, Morgan
    Globally, there is an increasing awareness of indoor air pollution and its resultant impacts. Indoor air pollution is a risk factor for multiple conditions that increases human mortality rates. There are limited studies on indoor air pollution in Arua, Uganda. This study quantified carbon monoxide and particulate matter (PM2.5) from households cooking with fixed mud charcoal stoves in Awindiri suburb, Arua Municipality. Fine particulate matter and carbon monoxide concentrations were measured for 24 h in kitchens. The results indicate that the average 24-h carbon monoxide (157.2 ± 86.2) ppm and fine particulate matter (473.3 ± 406.4) µgm−3 values obtained from households were both significantly (P < 0.001) higher than the recommended World Health Organisation levels. High fine particulate matter and carbon monoxide levels may be attributed to the inefficient fixed mud charcoal stove, poor ventilation, kitchen congestion, and long hours of cooking. High levels of fine particulate matter and carbon monoxide in the households could lead to serious long-term health effects on the occupants.