Browsing by Author "Chelangat Ngeno, Emily"

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    Environmental levels and human body burdens of per- and polyfluoroalkyl substances in Africa: A critical review
    (Science of the Total Environment, 2020) Ssebugere, Patrick; Sillanpää, Mika; Matovu, Henry; Wang, Zhanyun; Schramm, Karl-Werner; Omwoma, Solomon; Wanasolo, William; Chelangat Ngeno, Emily; Odongo, Silver
    Per- and polyfluoroalkyl substances (PFASs) are known organic pollutants with adverse health effects on humans and the ecosystem. This paper synthesises literature about the status of the pollutants and their precursors, identifies knowledge gaps and discusses future perspectives on the study of PFASs in Africa. Limited data on PFASs prevalence in Africa is available because there is limited capacity to monitor PFASs in African laboratories. The levels of PFASs in Africa are higher in samples from urban and industrialized areas compared to rural areas. Perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) are the dominant PFASs in human samples from Africa. Levels of PFOS and PFOA in these samples are lower than or comparable to those from industrialised countries. PFOA and PFOS levels in drinking water in Africa are, in some cases, higher than the EPA drinking water guidelines suggesting potential risk to humans. The levels of PFASs in birds’ eggs from South Africa are higher, while those in other environmental media from Africa are lower or comparable to those from industrialised countries. Diet influences the pollutant levels in fish, while size and sex affect their accumulation in crocodiles. No bioaccumulation of PFASs in aquatic systems in Africa could be confirmed due to small sample sizes. Reported sources of PFASs in Africa include municipal landfills, inefficient wastewater treatment plants, consumer products containing PFASs, industrial wastewater and urban runoff. Relevant stakeholders need to take serious action to identify and deal with the salient sources of PFASs on the African continent.
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    Polycyclic aromatic hydrocarbons in sediments and fish species from the White Nile, East Africa: Bioaccumulation potential, source apportionment, ecological and health risk assessment
    (Environmental Pollution, 2021) Abayi, Juma John Moses; Tombe Gore, Christopher; Nagawa, Christine; Bandowe, Benjamin A.Musa; Matovu, Henry; Mubiru, Edward; Chelangat Ngeno, Emily; Odongo, Silver; Sillanpaa, Mika; Ssebugere, Patrick
    The impact of oil exploration and production activities on the environment of sub-saharan African countries is not well studied. This study aimed at determining concentrations, sources, and bioaccumulation of 13 polycyclic aromatic hydrocarbons (PAHs) in sediments and fish from the White Nile near Melut oil fields, South Sudan. The study also assessed the ecological and human health risk associated with PAHs in this aquatic system. Total ( P 13) PAH concentrations ranged from 566 to 674 ng g 1dry weight (dw) in sediments, while those in fish were 191e1143 ng g 1 wet weight (ww). P 13PAH concentrations were significantly higher in C. gariepinus than in other fish species. Low molecular weight PAHs (LPAHs) dominated the profile of PAHs in sediments (constituted 95% of P P 13PAHs) and fish (97% of 13PAHs). Compared to Sediment Quality Guidelines of the United States Oceanic and Atmospheric Administration, the levels of LPAHs in this study were all above the threshold effect limits, but below the probable effect level, while those of high molecular weight PAHs (HPAHs) were all below the lowest effect levels. The carcinogenic potency equivalent concentrations of PAHs in L. niloticus and C. gariepinus were above the US EPA screening level; suggesting consumption of these species could adversely affect human health. Biota-sediment accumulation factor values (range: 0.006e3.816 g OC g 1 lipid) for PAHs showed high bioaccumulation of LPAHs in fish muscle, and that bioaccumulation decreased with increase in hydrophobicity of the compounds. This is possibly because LPAHs have higher aqueous solubilities which increases their bioavailability through water-gill transfers compared to HPAHs. Profiles of PAHs in the White Nile environment indicate predominant contribution from petrogenic sources, which could be attributed to presence of crude oil reservoirs and oil production operations. More research into the levels of other environmental pollutants in the oil-rich area is recommended.
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    Sustainable re-utilization of waste materials as adsorbents for water and wastewater treatment in Africa: Recent studies, research gaps, and way forward for emerging economies
    (Environmental Advances, 2022) Chelangat Ngeno, Emily; Mbuci, Kinyua E.; Chaker Necibi, Mohamed; Odhiambo Shikuku, Victor; Olisah, Chijioke; Ongulu, Roselyn; Matovu, Henry; Ssebugere, Patrick; Abushaban, Almotasembellah; Sillanpaa, Mika
    Access to clean water is a fundamental human right. However, due to the rapid urbanization and industrialization in many African countries, the emergence of a plethora of new classes of water contaminants coupled with aging wastewater treatment infrastructure and technologies, access to clean water has remained elusive especially to rural communities. Additionally, most countries in Africa cannot afford the capital investment associated with advanced and specialized treatment technologies. The solution seems to be the valorization of locallysourced waste materials and their use as adsorbents, flocculants/coagulants, or photocatalysts, to be included in current and future wastewater treatment facilities. The present review presents a concise and comprehensive compilation, and critique of recent research water purification studies in Africa using waste-based adsorbents. While the abundance of industrial and agricultural wastes presents opportunity for sustainable exploitation for water treatment, several gaps warrant further research. Specifically, future research should include life cycle assessment (LCA) of the wastewater treatment plants (WWTPs) and proposed technologies, in-depth cost analysis, use of environmentally relevant concentrations in simulated studies or real wastewaters and examination of removal efficiencies for biological contaminants such as viruses, bacteria among others. Waste materials are shown to be suitable candidates for delivery of effective and techno-economic adsorbents for water purification in African countries.