Browsing by Author "Lalah, Joseph O."

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    Effects of Zeolite X on Dissipation of Hexazinone from Agricultural Waste Waters in Western Kenya
    (2013-10) Agoro, David J.; Kowenje, Chrispin O.; Lalah, Joseph O.; Osewe, Elly T.; Ogunah, Joanne A.
    Dissipation of hexazinone in Zeolite X treated wastewater followed pseudo first-order kinetics giving a calculated half-life of 41 days compared to a half-life of 144 days in untreated wastewater. The herbicide degraded faster (0.0067 h-1) in treated than in nonzeolite- treated wastewater (0.0027 h-1) forming products A, B, C, D and E within the first 12 h. Zeolite X effectively catalyzed the formation of product A compared to the rest. Calculated rate constants for formation of products A, B, D and E were: 8.33 x 10-4 h-1, 5.65 x 10-4 h-1, 5.52 x 10-4 h-1 and 1.38 x10-3 h-1 respectively in non-zeolite-treated wastewater; and 3.988 x 10-3 h-1, 4.875 x 10-4 h-1, 4.745 x 10-4 h-1 and 2.82 x 10-3 h-1 respectively in zeolite-treated wastewater
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    Effects of Zeolites X and Y on the Degradation of Malathion in Water
    (2013) Ogunah, Joanne A.; Kowenje, Chrispin O.; Osewe, Elly T.; Lalah, Joseph O.; Jaoko, David A.; Koigi, Robert N.
    The inclusion of both zeolites X and zeolite Y significantly affected the dissipation of malathion in water. In the fresh water, malathion degradation followed a pseudo-first order kinetics with concomitant half-life dropping from 8.76 hours in fresh water to 4.44 and 6.65 hours up on the introduction of faujasite X and Y, respectively. Zeolite X had higher degradation efficiency as compared to the Y type. In pure fresh water, Malathion mainly hydrolyzed to form malathion monocarboxylic and dicarboxylic acids as the only degradation products. However, in the presence of zeolites X and Y, in addition to the degradation products obtained in the fresh water, dimethyldithiophosphate was also formed. Notably, all the degradation products obtained are environmentally benign compared to the parent malathion. Eventually, both the adsorption on the zeolite framework and zeolite catalyzed degradation processes contributed to the overall dissipation behavior of the malathion and its degradation products
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    Malaria vector control strategies. What is appropriate towards sustainable global eradication?
    (ELSEVIER, 2020-10) Ogunah, Joanne A; Lalah, Joseph O.; Schramm, Karl-Werner
    Malaria a mosquito-borne disease caused by Plasmodium remains to be a main global burden despite concerted efforts to eliminate it. While diverse control strategies have been put in place for mosquito-borne diseases, vector control continues to be a critical component in infection prevention. Vector control majorly focuses on the eradication of mosquitoes using a variety of chemical insecticides that includes organochlorides, carbamates, organophosphates, and pyrethroids. The use of conventional insecticide-based as mosquito control strategies poses several challenges such as the widespread development of insecticide resistance, environmental damage concerns, and effects on non-target organisms. These challenges create a demand for the development and use of alternative pest control strategies that are sustainable, safer, and environmentally friendly to mosquito vector management. This review provides insight into alternative sustainable interventions for mosquito vector control in the form of biorational pesticides. Biorational pesticides are pesticides that have little or no effect on humans and environments and include entomopathogenic microorganisms, insect growth regulators, and endosymbiotic bacteria. It also puts into perspective their environmental impacts, benefits, and challenges. Further, countries like Sri Lanka, that are certified as malaria free by World Health Organization (WHO) incorporated the use of entomopathogenic bacteria, insect growth regulators and larvivorous fish in their national vector control programs leading to the successful elimination of malaria in 2016. We therefore highlight success stories of the countries that have implemented these interventions bringing out the lessons for countries that are battling malaria epidemics.