Browsing by Author "Sifuna, Douglas"

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    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 William
    Recent 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, Exposure
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    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, 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 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.
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    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, Patrick
    Over 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 victoria