Browsing by Author "Shivoga, William"

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  • Publication
    Publication
    Assessment of Available Phosphates and Nitrates Levels in Water and Sediments of River Isiukhu, Kenya
    (Science and Education Publishing, 2020-06-22) Oremo, Jane; Orata, Francis; Owino, Joseph; Shivoga, William
    Surface water contamination has become one of the main environmental issues of concern and achallenge to the world population, especially in the developing world, that face potable or usable water security. Inthis study concentrations of available nutrients (PO43- and NO3-) in sediments and water along River Isiukhu, withinLake Victoria catchment area in Kenya are presented. Sediments and water samples were collected from 11sampling sites along River Isiukhu. Available phosphorus was determined by a Spectrophotometric method in whichthe ammonium phosphomolybdate complex, was reduced by ascorbic acid in the presence of antimony to give adistinct blue color complex. Available nitrate was measured spectrophotometrically at 420nm using UVI609PCUV/VIS Spectrophotometer. Physicochemical parameters such as temperature, pH, dissolved oxygen, turbidity,salinity, conductivity, were measured on-site using mobile Hydrolab Quanta. Phosphates concentrations rangedfrom 1.18 ± 0.09 to 3.28 ± 0.5 in water (mg/l) and 2.30 ± 0.03 to 4.51 ± 0.31 in sediment (mg/kg) andnitrates concentrations ranged from 0.15 ± 0.04 to 0.75 ± 0.03 in water (mg/l) and 0.75 ± 0.02 to 1.93 ± 0.05 insediment (mg/kg). The coefficient of variation (CV) depicted that all the physical-chemical parameters measuredvaried widely except pH and temperature. Pearson's correlation matrix was used to show the relationship betweennutrients concentrations in sediments and water and also for the physical-chemical parameters at significantdifferences accepted at P ≤ 0.05 . There was variation in Pearson correlation coefficient analysis for all theparameters tested.
  • Publication
    Publication
    Assessment of heavy metals in benthic macroinvertebrates, water and sediments in River Isiukhu, Kenya
    (Springer, 2019-10-16) Oremo, Jane; Orata, Francis; Owino, Joseph; Shivoga, William
    A major ecological challenge facing freshwater resources such as rivers is the influx of chemical contaminants from anthropogenic sources. A report on the levels of heavy metals, namely Zn, Cu, Cr, Cd and Pb in benthic macroinvertebrates, sediments and water along River Isiukhu, within Lake Victoria catchment area in Kenya is presented. Families of benthic macroinvertebrates that were investigated included Gerridae, Baetidae and Unionidae. Samples were digested using the appropriate acid combination and analysed using Spectra AAS Varian 200. Physicochemical parameters were measured on-site using mobile Hydrolab Quanta. Pearson’s correlation matrix and post hoc Tukey’s test were used to show the relationship between metal concentrations in the various matrices at significant differences accepted at p ≤ 0.05. Positive correlations were obtained for heavy metal concentrations in sediments and benthic macroinvertebrates with significant correlations observed for Zn (r = 0.655, p = 0.029) and Cu (r = 0.641, p = 0.034). Sediments presented the highest range of heavy metal concentrations compared to water and benthic macroinvertebrates and presented the only matrix with quantifiable Pb levels. The range in heavy metal concentration in benthic macroinvertebrates samples were as follows: Zn, 30.73–46.64, 21.93–38.17, and 26.85–41.69 mg/kg, Cu, 1.17–6.54, 1.11–3.87 and 1.15–5.79 mg/kg, Cr, 0.47–1.61, 0.22–0.74 and 0.25–0.92 mg/kg, for families Unionidae, Baetidae and Gerridae respectively. Heavy metal concentration profile along the river indicated an influx of pollutants from anthropogenic sources due to rapid urbanization along the river.
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    Publication
    Compatibility of Rhizobium inoculant and water hyacinth compost formulations in Rosecoco bean and consequences on Aphis fabae and Colletotrichum lindemuthianum infestations
    (Elsevier, 2014-04-01) Naluyange, Victoria; Ochieno, Dennis; Maingi, John; Ombori, Omwoyo; Mukaminega, Dative; Amoding, Alice; Odendo, M.; Okoth, S.; Shivoga, William; Muoma, John
    The common bean, Phaseolus vulgaris is an important crop for food security and nitrogen fixation through Rhizobium symbiosis. Commercial Rhizobium inoculants are being promoted to fix nitrogen and enhance bean production in the Lake Victoria basin. Rhizobium symbiosis depends on nutrients, especially phosphorus, which is widely applied as diammonium phosphate (DAP) in the Lake Victoria basin. Water hyacinth, Eichornia crassipes (Mart.) Solms-Laubach (Pontederiaceae) is being developed into compost, with perceived benefits of improving crop production and limiting its disastrous spread in Lake Victoria. High nutrient content in water hyacinth compost can stimulate Rhizobium nodulation and nitrogen fixation, consequently improving plant growth and pest resistance. However, it is not yet established whether Rhizobium inoculants and water hyacinth composts are compatible options for plant growth promotion and pest suppression in beans. A field experiment with two trials was conducted to assess the compatibility of commercial Rhizobium inoculant, DAP, cattle farmyard manure (FYM), and four formulations of water hyacinth compost i.e., water hyacinth only (H), with molasses (H+Mol), cattle manure culture (H+CMC) or effective microbes (H+EM). Rhizobium inoculated plants had high number of root nodules when grown with H+CMC and H+EM. Plants were large in size with short development period when grown with the composts, especially H+CMC and H+EM. Those grown with H+EM produced high number of flowers. Rhizobium inoculated plants had high anthracnose incidence than non-inoculated ones when grown with H+CMC. Those grown with H+EM had low anthracnose incidence, but was high in FYM. During flowering, Rhizobium inoculated plants had higher Aphis fabae population than non-inoculated ones when grown in FYM or without fertilizer. Those grown with H+EM had the lowest A. fabae population. Yields in water hyacinth compost were improved, especially for H+CMC in the second trial. DAP treated plants had more flowers and pods having heavy seeds, with low anthracnose and A. fabae infestations; but had low germination rates that reduced the yields. In conclusion, the commercial Rhizobium inoculant is predominantly compatible with water hyacinth compost formulations containing effective microbes and cattle manure culture, which could enhance tolerance of bean plants to aphids and possibly to anthracnose disease. These two water hyacinth compost formulations need further investigation for their potential in enhancing food production and alleviating the water hyacinth problem in the Lake Victoria basin.
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    Publication
    Composition and design of vegetative filter strips instrumental in improving water quality by mass reduction of suspended sediment, nutrients and Escherichia coli in overland flows in eastern escarpment of Mau Forest, Njoro River Watershed, Kenya
    (Springer Link, 2016-06-13) Olilo, Casianes; Onyando, Jack; Moturi, Wilkister; Muia, Wairimu; Roegner, Amber; Ogari, Zachary; Ombui, P.; Shivoga, William
    This study assessed the effect of vegetative filter strip (VFS) in removal of suspended sediment (SS), total nitrogen, total phosphorus and Escherichia coli (E. coli) in overland flow to improve receiving water quality standards. Four and half kilograms of cowpat manure was applied to the model pasture 14 m beyond the edge of vegetated filter strip (VFS) comprising 10-m Napier grass draining into 20-m Kikuyu grass (VFS II), 10-m Kikuyu grass draining into 20-m Napier grass (VFS III) and native grass mixture of Couch–Buffel (VFS I-control). Overland flow water samples were collected from the sites at positions 0, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25 and 30 m along the length of VFSs. E. coli removal by Napier grass VFS was on the order of log unit, which provided an important level of protection and reduced surface-flow concentrations of E. coli to below the 200 (CFU 100 mL−1) recommended water quality standards, but not for nutrients and SS. The Napier grass showed highest efficiency (99.6 %), thus outperforming both Kikuyu grass (85.8 %) and Couch–Buffel grasses VFS (67.9 ± 4.2 %) in removing E. coli from overland flow. The low-level efficiency of native Couch–Buffel grasses in reducing E. coli in overland flow was because of preferential flow. Composition and design of VFS was instrumental and could be applied with a high potential of contracting the uncertainty in improving water quality standards through mass reduction of SS, nutrients and E. coli load in watersheds.
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    Publication
    Faecal pollution and solar purification of community water sources within Lake Naivasha basin, Kenya
    (Journal of Water, Sanitation and Hygiene for Development, 2015-06) Donde, Oscar; Muia, Wairimu; Wanga, Lucy; Shivoga, William; Trick, Charles; Creed, Irena
    As in other parts of Africa, and in other developing nations, the rise in the human population and anthropogenic activities within the Lake Naivasha basin is causing an increase in human health risks due to faecal contamination of domestic water sources. This study investigated faecal pollution of community water sources within the Lake Naivasha basin by measuring the densities of total coliforms, Escherichia coli, intestinal enterococci, Clostridium perfringens and heterotrophic bacteria in Lake Naivasha, the Malewa and Gilgil Rivers, and boreholes using membrane filtration techniques and heterotrophic plate count procedures. Selected physico-chemical parameters were also measured in situ from all the water sources sampled. Lakes and rivers had significantly higher microbial abundances than boreholes. Unlike boreholes, surface sources (rivers and lake) showed significant variation with respect to sampling sites for all the microbiological parameters (P< 0.05). The use of solar radiation in water disinfection with temperatures of 75 WC after 30 minutes from pasteurization point (time zero) fully eradicated E. coli and total coliforms from all the water sources. In conclusion, there is faecal pollution in water sources used by communities within the Lake Naivasha basin. The use of solar radiation is therefore recommended for water purification to reduce likely incidences of waterborne diseases.