Wambu E.W.,Jaramogi Oginga Odinga University of Science and Technology |
Agong S.G.,Jaramogi Oginga Odinga University of Science and Technology |
Anyango B.,Jaramogi Oginga Odinga University of Science and Technology |
Akuno W.,Jaramogi Oginga Odinga University of Science and Technology |
Akenga T.,University of Eldoret
BMC Public Health | Year: 2014
Background: Only a few studies to evaluate groundwater fluoride in Eastern Africa have been undertaken outside the volcanic belt of the Great Eastern Africa Rift Valley. The extent and impact of water fluoride outside these regions therefore remain unclear. The current study evaluated fluoride levels in household water sources in Bondo-Rarieda Area in the Kenyan part of the Lake Victoria Basin (LVB) and highlighted the risk posed by water fluoride to the resident communities. The results, it was anticipated, will contribute to in-depth understanding of the fluoride problem in the region. Methods. A total of 128 water samples were collected from different water sources from the entire study area and analyzed for fluoride content using ion-selective electrodes. Results: Lake Victoria was the main water source in the area but dams and open pans (39.5%), boreholes and shallow wells (23.5%), and streams (18.5%) were the principal water sources outside walking distances from the lake. The overall mean fluoride content of the water exceeded recommended limits for drinking water. The mean water fluoride was highest in Uyoma (1.39±0.84 ppm), Nyang'oma (1.00±0.59 ppm) and Asembo (0.92±0.46 ppm) and lowest in Maranda Division (0.69±0.42 ppm). Ponds (1.41±0.82 ppm), springs (1.25±0.43 ppm), dams and open pans (0.96±0.79 ppm), and streams (0.95±0.41 ppm) had highest fluoride levels but lake and river water did not have elevated fluoride levels. Groundwater fluoride decreased with increasing distance from the lake indicating that water fluoride may have hydro-geologically been translocated into the region from geochemical sources outside the area. Conclusions: Lake Victoria was the main water source for the residents of Bondo-Rarieda Area. Majority of in-land residents however used water from dams, open pans, boreholes, shallow wells, ponds and streams, which was generally saline and fluoridated. It was estimated that 36% of children living in this area, who consume water from ground sources from the area could be at the risk of dental fluorosis. © 2014 Wambu et al.; licensee BioMed Central Ltd.
Xue L.-J.,University of Georgia |
Guo W.,University of Georgia |
Guo W.,Guangdong Academy of Forestry |
Yuan Y.,Michigan Technological University |
And 10 more authors.
Plant Cell | Year: 2013
Salicylic acid (SA) has long been implicated in plant responses to oxidative stress. SA overproduction in Arabidopsis thaliana leads to dwarfism, making in planta assessment of SA effects difficult in this model system. We report that transgenic Populus tremula × alba expressing a bacterial SA synthase hyperaccumulated SA and SA conjugates without negative growth consequences. In the absence of stress, endogenously elevated SA elicited widespread metabolic and transcriptional changes that resembled those of wild-type plants exposed to oxidative stress-promoting heat treatments. Potential signaling and oxidative stress markers azelaic and gluconic acids as well as antioxidant chlorogenic acids were strongly coregulated with SA, while soluble sugars and other phenylpropanoids were inversely correlated. Photosynthetic responses to heat were attenuated in SA-overproducing plants. Network analysis identified potential drivers of SA-mediated transcriptome rewiring, including receptor-like kinases and WRKY transcription factors. Orthologs of Arabidopsis SA signaling components NONEXPRESSOR OF PATHOGENESIS-RELATED GENES1 and thioredoxins were not represented. However, all members of the expanded Populus nucleoredoxin-1 family exhibited increased expression and increased network connectivity in SA-overproducing Populus, suggesting a previously undescribed role in SA-mediated redox regulation. The SA response in Populus involved a reprogramming of carbon uptake and partitioning during stress that is compatible with constitutive chemical defense and sustained growth, contrasting with the SA response in Arabidopsis, which is transient and compromises growth if sustained. © 2013 American Society of Plant Biologists. All rights reserved.
Agency: Cordis | Branch: H2020 | Program: RIA | Phase: WATER-5c-2015 | Award Amount: 2.99M | Year: 2016
FLOWERED objective is to contribute to the development of a sustainable water management system in areas affected by fluoride (F) contamination in water, soils and food in the African Rift Valley countries (Ethiopia, Kenya, Tanzania), thus to improve living standards (environmental, health and food security) of its population. FLOWERED aims to study, test and implement innovative defluoridation technologies for drinking and irrigation water that will mainly operate at small village scale and to develop an integrated, sustainable and participative water and agriculture management at a cross-boundary catchment scale. On the basis of the complexity of the issue of water de-fluoridation, the proposed scientific approach in FLOWERED is based on a detailed knowledge of the geological and hydrogeological setting that controls contamination of water that constitute the prerequisite for the implementation of a sustainable water management and for the proposal of sustainable and suitable strategies for water sanitation and agricultural system. Innovative agricultural practices will be assessed, aiming to mitigate the impacts of F contamination of water and soil on productivity of selected food and forage crops and dairy cattle health and production. The development of an innovative and shared Geo-data system will support the integrated, sustainable and participative management system. FLOWERED, focusing on innovative technologies and practices and taking into account local experiences, will implement an integrated water and agriculture management system and will enable local communities to manage water resources, starting from using efficient defluoridation techniques and applying sustainable agricultural practices. The integrated approaches improve knowledge for EU partners, local researchers, farmers and decision makers. The Project through the involvement of SMEs will strengthen the development co-innovative demonstration processes as well as new market opportunities.
Njoroge R.W.,University of Eldoret |
Macharia B.N.,Moi University |
Sawe D.J.,Moi University |
Maiyoh G.K.,Moi University
Toxicology Reports | Year: 2015
The use of crude kerosene as a dietary supplement in boarding schools has been a common practice in east Africa and other countries for many years, with the belief of it reducing the sex drive (libido) at the pubertal stage. There is however no scientific basis for this belief. The present study aimed at using a rat animal model to investigate the effects of crude kerosene on serum testosterone levels, aggression and its possible toxic effects. Fifteen male albino rats of approximately similar age and average weights were put into three groups of five animals each; the control group (placebo), low kerosene dose (10. μl/day) group and high kerosene dose (300. μl/day) group. ELISA was used to determine the serum testosterone levels. During treatment, changes in aggression were observed and noted. Liver toxicity was determined using enzyme assays, total protein and albumin while renal toxicity was monitored using serum creatinine levels. A full hemogram was conducted to determine hematological effects. Various tissue biopsies were obtained and examined using histopathological techniques for evidence of toxicity. Contrary to the common belief, our findings showed an overall increase of serum testosterone levels of up to 66% in the low dose and 75% in the high dose groups, with an increasing trend by the end of the study. The high dose group showed significantly increased levels of white blood cells (WBC) (. p=. 0.036), red blood cells (RBC) (. p=. 0.025), hematocrit (HCT) (. p=. 0.03), red cell distribution width (. p=. 0.028) and platelets (. p=. 0.017). The histological results of the stomach indicated chronic gastritis. © 2014 The Authors.
Chibole O.K.,University of Eldoret
Ecohydrology and Hydrobiology | Year: 2013
To investigate the water quality status at catchment scale, the MIKE 11 modeling system (DHI) was used on the Sosiani, western Kenya. The river's catchment was delineated according to land-use practice into forested (Fz), agricultural (Az) and urban (Uz). Rainfallrunoff processes were modeled using NAM (DHI) and the hydrodynamic model was built using the MIKE 11 HD module. Water quality (WQ) modeling was limited to the oxygen cycle. Model calibration was done on the basis of available measured WQ data at Fz-Az; Az-Uz boundaries. Simulated data versus observed data show model efficiency of 0.70. The Uz contributes 75% of BOD flux in the catchment. © 2013 European Regional Centre for Ecohydrology of Polish Academy of Sciences.
Modelling hydrological processes, crop yields and NPS pollution in a small sub-tropical catchment in South Africa using ACRU-NPS [Modélisation des processus hydrologiques, du rendement des cultures et de la pollution azote-phosphore-sédiment dans un petit bassin versant subtropical d’Afrique du Sud utilisant ACRU-NPS]
Kollongei K.J.,University of KwaZulu - Natal |
Kollongei K.J.,University of Eldoret |
Lorentz S.A.,University of KwaZulu - Natal
Hydrological Sciences Journal | Year: 2015
The Agricultural Catchment Research Unit—Nitrates, Phosphorous and Sediments (ACRU-NPS) model, which simulates runoff, sediment and nutrient (NO3 and P) production in agricultural catchments, is used to evaluate the impact of farming practices and land-use changes on crop yields, water discharge, sediment and nutrient loads in the 41-km2 Mkabela catchment in the KwaZulu-Natal midlands, South Africa. The ACRU-NPS model was modified with the following objectives: (a) to develop and incorporate algorithms to simulate crop growth and NPS pollution dynamics in process zones and control features; (b) simulate sediment and nutrient production from land segments for various land uses; (c) model crop yield where crop growth is influenced by water and nitrogen stress; and (d) simulate sediment and nutrient fate at controls and buffers in the stream network. Five management practice scenarios were simulated and run with a series of fertilizer management applications. The resulting crop yields, water discharge, sediment and nutrient loadings were analysed. On average, doubling fertilizer application from base rates resulted in the highest sugarcane yield increase of 5 t/ha, zero fertilizer application resulted in the highest sugarcane yield reduction of 11 t/ha, while applying deficit irrigation, with base fertilizer application rates retained, resulted in 16 t/ha sugarcane yield increase. Flood attenuation and retention capacities for the total non-point source (NPS) pollutants for the period 2006–2012 were also investigated in the study area. © 2015 IAHS.
Masese F.O.,University of Eldoret |
Omukoto J.O.,Kenya Marine and Fisheries Research Institute |
Nyakeya K.,Kenya Marine and Fisheries Research Institute
Ecohydrology and Hydrobiology | Year: 2013
Degradation of aquatic ecosystems in the Lake Victoria basin (LVB) and the rest of East Africa has elicited concern because of its bearing on social and economic development. Rapid population growth, industrialization and its associated urbanization, agricultural intensification and habitat loss have increased pressure on the integrity of water resources. Costs associated with traditional approaches to monitoring water quality have become prohibitive while not giving reliable early warning signals on resource condition to aquatic resource managers. The purpose of this paper is to explore approaches to developing macroinvertebrate- and fish-based biomonitoring tools in the LVB and East Africa and the challenges they face through a review of studies that have been carried out in the region. The hypothesis is that aquatic biota in the LVB provides cost-effective and integrative measures of the physical and chemical habitat conditions thus necessitating their use in assessment and monitoring of water resources. In the LVB macroinvertebrate and fish based indices of biotic integrity (IBIs) have demonstrated their utility in identifying sources of impairment, determining the extent of impacts and stand to give natural resource managers a scientifically defensible rationale for developing guidelines for conservation and management. Despite this significant step, however, adoption and use of indices as part of regular monitoring programs are yet to be realized. We recommend for the advancement and adoption of biological criteria as an integrated approach to monitoring human-induced stress in riverine ecosystems of the East Africa region. © 2013 European Regional Centre for Ecohydrology of Polish Academy of Sciences.
Motochi I.,University of Eldoret |
Makau N.W.,University of Eldoret |
Amolo G.O.,University of Eldoret
Diamond and Related Materials | Year: 2012
Metal contacts on clean, hydrogenated and oxygenated diamond surfaces have been studied using ab initio Density Functional Theory (DFT). Five metals, i.e., gold, titanium, tantalum, vanadium and palladium on the three surfaces were considered. Gold and palladium were found to form weak bonds on clean, hydrogenated or oxygenated diamond (111) surfaces compared to the other three metals. Bulk properties were also studied following the formation of the respective ohmic contacts on the three surfaces. The clean diamond surface was found to have surface states which were modified by oxygen but removed by hydrogen. Density of states studies revealed that all the investigated metals had an effect on the electrical properties of the diamond surface. A peak that was characteristic of diamond was observed at ≈-11.8 eV. For the clean diamond surface terminated with gold and palladium, states due to Au-2p orbitals were observed at - 2.5 eV and ≈-1.5 eV, while Pd-5s orbitals were located at ≈-1.7 eV and - 0.5 eV on the same surface. Titanium, tantalum and vanadium showed unique states at high binding energies of ≈-38 eV for vanadium, ≈-34 eV for tantalum and ≈-32.5 eV for titanium, which were thought to be responsible for their strong bonding. © 2011 Elsevier B.V. All rights reserved.
Kimanzi J.K.,University of Eldoret |
Sanderson R.A.,Northumbria University |
Rushton S.P.,Northumbria University |
Mugo M.J.,Karatina University
ORYX | Year: 2015
Poaching with snares has been identified as the main cause of decline of the endemic roan antelope Hippotragus equinus langheldi in Ruma National Park, Kenya, from > 200 in 1979 to 37 in 2009. However, the spatial snaring patterns in the Park are not clearly understood. The focus of our study was to map the spatial distribution of snares in the Park and to identify the factors influencing this distribution, to develop effective methods of wildlife protection. Using data collected from 56 sample plots during 2006-2008, coupled with geographical information system techniques, we investigated the association between the occurrence of snares and the distribution of geographical features (slope, elevation), infrastructure (roads, fences), essential resources for wildlife (water, salt licks, forage), roan locations and wildlife density. Ripley's L function for assessing complete spatial randomness indicated that snares occurred in clumps (hotspots) up to 4 km apart. Negative binomial regression indicated that these hotspots occurred (1) near water resources, salt licks and the Park boundary, (2) far from roan locations and Park roads, (3) in areas with low gradients and low wildlife density, and (4) in areas with burned vegetation. We recommend concentrating routine security patrol efforts and resources on snare hotspots to reduce snaring and to protect the roan antelope and other threatened wildlife. Copyright © Fauna & Flora International 2014.
Mugalavai E.M.,Masinde Muliro University of Science and Technology |
Kipkorir E.C.,University of Eldoret
Journal of Water and Climate Change | Year: 2015
Uncertainties caused by climate change and population explosion require suitable methods for estimating grain yield during the growing seasons. This paper evaluates the applicability of the AquaCrop model in the region of western Kenya. The objectives of the study were to: simulate the long-term maize crop yields for the region using AquaCrop model for variable climate scenarios, and estimate the expected yield for the ongoing season. Climate was classified into below normal (