Browsing by Author "Olisah, Chijioke"

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    Organochlorine pesticide residues in Uganda’s honey as a bioindicator of environmental contamination and reproductive health implications to consumers
    (Ecotoxicology and Environmental Safety, 2021) Mukiibi, Stuart Ben; Nyanzi, Steven Allan; Kwetegyeka, Justus; Olisah, Chijioke; Matthew Taiwo, Adewale; Mubiru, Edward; Tebandeke, Emmanuel; Matovu, Henry; Odongo, Silver
    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 (GCECD). The mean level of ΣDDTs in all the soil samples was 503.6 μg/kg dry weight (d.w). ΣDDTs contributed 92.2% to the ΣOCPs 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 ΣDDTs was 20.9 μg/kg. ΣDDTs contributed 43.3% to ΣOCPs 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.
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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.