Notices
Professor Prof.jumba Isaac Publications | ||||
1 | 2015 | Occurrence, Abundance And Distribution Of Benthic Macro Invertebrates In The Nyando River Catchment, Kenya Click to View Abstract
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2 | 2015 | Organochlorine Pesticide Residue Levels In Soil From The Nyando River Catchment, Kenya Click to View Abstract Soil samples were collected from six locations representative of the Nyando River catchment area of the Lake Victoria over a period of two years. Sampling was done four times in the year in February, May, September and December 2005 and 2006 in farms where maize, tea, sugar cane, coffee, rice and vegetables have been grown over the years. This coincided with the effects of different seasons and farming activities on residue levels of the pesticides in use. The objective was to investigate levels and distribution of organochlorine pesticides that have either been banned or are restricted for use in Kenya. Organochlorine pesticides investigated were DDT, lindane, aldrin, dieldrin, heptachlor, endrin, endosulfan (both α- and β- isomers and endosulfan sulphate), the sum is called “total” or Σendosulfan and methoxychlor. Prior to the ban or restriction in use, these pesticides had found wide applications in public health for control of disease vectors and in agriculture for control of crop pests. The analysis revealed presence of all the targeted pesticides with the highest mean concentrations for methoxychlor 138.97±1.517 μg/kg, Σendosulfan (30.267±2.098μg/kg), aldrin (18.317±0.276 μg/kg), respectively. The results show the presence of these pesticides in soils in the basin and this could be impacting negatively on the ecosystem health of the area. | ||
3 | 2014 | Dynamics Of Chlorpyrifos In Water From Upper Tana River In Kenya Click to View Abstract
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4 | 2014 | Impacts Of Pesticides On Human Health And The Environment In The River Nyando Catchment, Kenya Click to View Abstract
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5 | 2013 | Influence Of Acacia Senegal Varieties On Quality Of Gum Arabic In Baringo District Kenya. Click to View Abstract A study was done to determine the influence of Acacia senegal variety and var.kerensis on quality of gum arabic in solit, kapkun, kimorok and maoi, Marigat division, baringo District. Soil and gum arabic samples were collected, dried and analysed to establish their chemical characteristics. Gum nitrogen from A. senegal variety senegal in kapnun and solit was negatively correlated to soil nitrogen (r=-0.28), while gum nitrogen from variety kerensis at kimorok and Maoi was positively correlated to soil nitrogen (r=0.16), respectively. High nitrogen content in soils was significantly correlated to high content of nitrogen (0.30%) in gum arabic obtained from A.senegal varieties. Gum copper was highly correlated to soil copper (r=0.09;p<0.01), soil iron was highly correlated to gum iron (r=0.09; p<0.05) and soil manganese and gum manganese was negatively correlated (r= -0.08; p<0.05). Gum zinc from A. senegal variety senegal at kapkun and Solit was negatively correlated to soil nitrogen and (r=-0.15), respectively. Nitrogen, iron, manganese and zinc contents in gums from A.senegal varieties fell within the ranges of the international standard specifications (0.26 to 0.39% N, iron (730 to 2490 ppm), manganese (69 to 117 ppm) and zinc (45 to 111ppm), respectively. A.senegal variety senegal in Solit and kapkun produced better quality of gum arabic than A. senegal variety kerensis in kimorok and Maoi. | ||
6 | 2012 | Minerals Deficiency Diagnosis In Grazing Cattle Of Uasin Gishu District, Kenya Click to View Abstract Grazing cattle in the tropics and especially in Uasin Gishu district depend on a variety of plant species for their mineral supply. One area of concern is that the grazing cattle may be experiencing mineral imbalances due to lack of proper mineral mapping of the region to ascertain the levels of imbalance. A study conducted in the Uasin Gishu region revealed severe deficiencies of mainly Cu (3.30 ± 0.90) and Zn (6.70 ± 0.40) in soils, the elements Na (1.00 ± 0.39), K (11.80 ± 5.00), Ca (0.57 ± 0.19), Mg (1.35 ± 0.72), P (6.34 ± 3.22), Fe (56.00 ± 0.53), Cu (5.32 ± 2.84), Zn (19.50 ± 8.20) in pasture species and the elements Fe (2.43 ± 1.53), Mn (0.26 ± 0.14 ), Cu (0.60 ± 0.17), Mg (0.02 ± 0.01) in animal blood. The study recommends immediate mineral supplementation schemes to grazing cattle in the region and encouragement of certain pasture species in the region. | ||
7 | 2011 | Soil-plant Composition In Relation To Mineral Requirements For Grazing Cattle In Uasin Gishu District Click to View Abstract Livestock industry is one of the major contributors to the country's GDP and provides one third of the total available food in the country. Mineral deficiencies and imbalances in soils and forages can be a challenge in relation to production in grazing cattle in developing countries. A number of factors influence the availability of such minerals in terms of proper growth and development of cattle. The study was done in selected parts of Uasin Gishu and revealed severe nutritional deficiencies in soils and forages. The study also revealed a number of factors that influenced mineral concentration in the region. The study has suggested recommendations to help identify and alleviate any constraints on animal health and production. | ||
8 | 2010 | Assessment Of Physical Properties Of Gum Arabic From Acacia Senegal Varieties In Baringo District, Kenya Click to View Abstract A study was conducted to assess the physical properties of gum arabic obtained from two Acacia Senegal varieties (var.Senegal and Mar.kerensis). in Marigat division, Baringo district. Gum arabic samples from the experimental sites at Solit, Kapkun, Kimorok and Maoi were collected, dried and analysed to establish their physical characteristics. Moisture content in gum arabic obtained from variety kerensls in Kimorok and Maoi (17.5 ± 1.00 and 15.4 ± 0.50%) were significantly higher (P < 0.05) than those of variety Senegal in Solit and Kapkun (15.0 ± 0.50 and 14.9 ± 1.80%), while internal energy (33.4 and 33.76%) were not significantly different (P > 0.05) from those of variety Senegal found in Kapkun and Solit (33.0 and 32.96%), respectively. Ash content in gum arabic from variety Senegal in Solit and Kapkun (2.94 and 3.16%) was higher (P < 0.05) than those of variety kerensis found in Kimorok and Maoi (2.88 and 2.72%). In Kapkun, volatile matter in gum arabic from variety Senegal (64.2%) was higher (P < 0.05) than the quantities of variety kerensis found in Kimorok, Solit and Maoi (63.8, 63.7 and 63.6%), respectively. Moisture content in gum arabic from variety Senegal in Solit and Kapkun (15.0 ± 0.40 and 14.9 ± 1.80%) fell within international specifications (13 to 15%), while variety kerensis in Kimorok and Maoi (17.5 and 15.4%) fell outside the specifications. Moisture, ash and volatile matter contents in gum arabic from A. Senegal variety Senegal were 14.9, 3.16 and 64.24%, while A. Senegal variety kerensis had 15.2, 2.88 and 63.8%, respectively. Moisture content in gum arabic from A. Senegal variety Senegal fell within international specifications while A. Senegal variety kerensis fell outside the specifications. Ash, volatile matter and internal energy contents in gum arabic from A. Senegal variety kerensis and variety Senegal fell within the specifications. The gum arabic from A. Senegal variety Senegal in Solit and Kapkun was of better quality than that of A. Senegal variety kerensis in Kimorok and Maoi. | ||
9 | 2010 | Diagnosis Of Trace Element Nutritional Disorders In Herbivores: A Case Study In Lake Nakuru National Park, Kenya Click to View Abstract
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10 | 2008 | Alternative Energy Sources From Mui Basin In Kitui District, Kenya - A Case Of Coal Click to View Abstract
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11 | 2007 | Animal Health Problems Attributed To Environmental Contamination In Lake Nakuru National Park, Kenya: A Case Study Strongly Suggest Heavy Metal Poisoning In The Waterbuek Kohiis Cllipsiprymnus Dcfassa (Ruppel 1K35) Click to View Abstract Abstract. A study was conducted in which samples ol soil. forage, as well as serum, bone, kidney, and liver of waterbuck were collected from Lake Nakuru National Park. The objective was to determine the ecosystem health status in older to establish the causes of animal health problems previously re¬corded in some sections of the Paik. Trace element analysis in serum indicated occurrence ol copper (Cu) deficiency in the north and eastern sections of the Park where mean values were marginal (range: 0.36-0.81. mean: 0.62 mg/1) compared to concentrations recorded in the western part of the Park (range: 0.69 1.48. mean: 1.22 mg/l). Bone analysis on dry matter basis (DM) indicated higher (p < 0.01) levels of cadmium (Cd. 0.437 nig/kg), fhioride (F, 3178 mg/kg). and lead (Pb. 20.62 mg/kg) in animals from the east compared to those from the west (0.002. 1492, 4.87 mg/kg. respectively), suggesting heavy exposure. In addition, samples from the east had much lower than normal calcium (Ca)-to-phosphorus (P) ratios (mean: 1.9:1) compared to those recorded in the west (2.2:1). suggesting poor bone minerali/ation There was a higher concentration of Cd in the kidney (16.24 mg/kg. p < 0.05) and Pb in the liver (58.3 mg/kg. /; < 0.01) in animals from the east compared to those in the west (12.92 and 36.2 mg/kg, respectively), but the converse was true of Cu The liver Cu status was better in animals from the west with, concentrations (mean: 21.7 mg/kg) being about twice those recorded in the east (11.9 mg/kg DM). Forage analysis revealed prospects of Ca, P, and Cu deficiencies in the entire Park. However, in the northeastern section of the Park (measuring 50 ha) where waterbuck residence times are high, forage concentrations of Cd (0.31 mg/kg DM), molybdenum (Mo. 7.20 mg/kg DM). Pb (2.88 mg/kg DM), and /inc (7.n. 126 mg/kg DM) were an order of magnitude greater (p < 0.01) than the levels recorded in the rest of the Park (ranges: 0.133 0.165, 3.69 5.61. 0.485 0.621. 11.6 17.4 mg/kg DM, respectively). These disparities were attributed to a higher soil concentration of CM (2.77 mu/ku DM). Pb (85.1 msi/k DM) and 7,n (1414mg/kg DM i n this section compared lo the rest of the Park (ranges; 0 Id o 15. 5.02 6.26. 1,49 5.44 mg/kg DM. respec¬tively), and su»ngly suggest heavy metal contamination as the source ol annual health problems in the Park. | ||
12 | 2006 | THE STATUS OF EFFLUENT TREATMENT AND SAFE WASTE DISPOSAL OF TOXIC AND OBSOLETE PESTICIDES UNDER THE STOCKHOLM CONVENTION Click to View Abstract INTRODUCTION KENYA COUNTRY PAPER: UNIDO-RENPAP WORKSHOP, BOGOR INDONESIA 18"1 - 20'" SEPTEMBER, 2006 | ||
13 | 2006 | KENYA NATIONAL INVENTORY OF PERSISTENT ORGANIC POLLUTANTS (POPs) UNDER THE STOCKHOLM CONVENTION. GEF/UNEP/GoK - PART IV: Identification And Quantification Of Dioxins And Furans Releases In Kenya. Click to View Abstract SUMMARY | ||
14 | 2005 | The Status Of Persistent Organic Pollutants In Lake Victoria Catchment. Proc. Click to View Abstract The use of most organochlorine pesticides has been banned or restricted in the republic of Kenya under the Rotterdam and Stockholm convention due to high levels of persistence in the environment and toxicity to nontarget organisms. Studies conducted in some parts of the country have revealed that residue levels of these compounds are still in the environment. However, the residues of these compounds have not been exhaustively studied in the Lake Victoria catchment area. This study was set to investigate the residues levels of p,p-DDT, o,p'-DDE, p.p-DDD, g-HCH, D-HCH, a-HCH, Aldrin, and Dieldrin, in water samples from Lake Victoria catchment. Samples were collected during the short rain, dry and wet seasons and analysed using gas chromatography equipped with electron capture detector. Residue levels ranging from below detection limit (BDL)-0.44 ug/l in river Nzoia water, between BDL-0.34 ug/l in river Sio water, BDL- 0.26 ug/l in water from Sio Port, and between BDL-0.31 ug/l in water from lake Victoria at Marenga Beach were detected. | ||
15 | 2005 | Variation Of Physico-chemical Properties Of Palm Oil With Temperature Click to View Abstract
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16 | 2004 | Micronutrient Zinc Deficiency As A Possible Co-factor In The Transmission And Progression Of HIV/AIDS In Kenya. Afri. J. Food, Agric., Nutr. And Development Vol. 4 (2). Also Available At Www.talcuk.org: Click to View Abstract ABSTRACT Key words: Micro nutrient zinc, underutilized arsenal, combating, hiv/aids, SUB-SAHARAN Africa | ||
17 | 2004 | The Macro Mineral Composition Of Forages In The Mount Elgon Region Of Kenya Click to View Abstract
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18 | 2003 | The Distribution, Metabolism And Toxicity Of 14C-DDT In Model Aquarium Tanks With Fish And Sediment Simulating A Tropical Marine Environment. Click to View Abstract Studies were conducted on the distribution, fate and metabolism of DDT in a model ecosystem simulating a tropical marine environment of fish, Gabions nudiceps, Leihrinuf haruk, Cohious keineiis, Gnhiota nebutosis and white shrimp iPanaeus seliferus), show that DDT concentration in the water decreases rapidly within the first 24 h. Rapid accurr. • ution of the pesticide in the biota also reaches a maximum level in 24 h before graJuiiiy declining The bioaccumulution factors calculated for the fish specie.! (G. keinesis) and white shrimp '(P. Stiiferu!) were 270 and 351, respectively, after 24 h There was a steady build up of DDT residues in the sediment during the first 24 h which continued to a maximum concentration of 6 66 ng g in the sea-water fish sediment ecosystem after 3 weeks and 5.27ngg in the seawater/shrimps/sediment ecosystem after 2.7 days The depuration of the accumulated pesticide was slow with only 54% lost in G. nudiceps within 3 days of exposure in fresh sea water. By contrast, depuration was fast in the while shrimp, which lost 97% of the accumulated pesticide under the same conditions. DDT was found to be toxic to two of the fish species, (G. nebulmis and /_. huruk) and to white shnmp, and the degree of toxicity was dependent on the particular species. The 24 h LCyj al room temperature lor the fish species G. nebulous and white shrimp was found to be 0.011 and O.I 16mg kg. respectively. These levels are comparable to the ones recorded for the temperate organisms. Degradation of DDT to its primary metabolites. DDE and DDD. uas found in all the compartments of the ecosystem with DDE being the major metabolite in the fish, shrimps and sediment, while in se.iwater. DDD dominated as the major metabolite. | ||
19 | 2003 | Organochlorine Pesticide Residues In Tana And Sabaki Rivers In Kenya. Bull. Click to View Abstract
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20 | 2003 | Dissipation, Distribution And Uptake Of 14C-Chloropyrifos In A Model Tropical Seawater/Sediment/Fish Ecosystem. Bull. Click to View Abstract Chlorpyrifos, O,O-diethyl-O-(3,5,6-trichloro-2-pyridyl) phosphorothioate, is one of the most widely used organophosphorous pesticides worldwide due its high efficacy (Carvalho et al. 1992; Liu et al. 2001, Meikle and Youngson 1978). In Kenya, Dursban formulations are mainly used for protection of horticultural fruits and vegetables (Lalah 1994), Because of its low water solubility (0.4 mg/L) and high hydrophobicity (log Kow of 5.27), it is believed that chlorpyrifos would be able to partition easily onto aquatic sediments and macrophytes where it can pose dangers to benthic organisms (Ronday et al. 1998). It is also quite a volatile toxicant due to its low vapour pressure (2.5 mPa at 25 °C) and low air-to-water partition coefficient (8.9 10"4 at 25 °C) and its residues have been detected in air and rainwater samples (Liu et al. 2001).Increasing use of chlorpyrifos also causes a lot of anxiety to environmentalists and toxicologists because it is toxic to both humans and wildlife. As an irreversible inhibitor of acetylcholinesterase, it can cause impairment in mammalian brain cell development (Lund et al. 2000; Jeanty et al 2001; Jett et al 1999; Slotkin et al. 2001). Widespread use of this compound is therefore considered to be of great danger particularly to pregnant women and children Some of its reported toxicities to aquatic organisms include 96 hr LCNo of 0.13 |.ig/L and 96 hr LC?o of 0.035 Ug/L in adult Neomysis integer and Americamysis bahia, respectively (Roast et al. 1999). Although its toxicity in mammalian and aquatic organisms has been well documented, its fate and effects on aquatic ecosystems in tropical conditions where it is expected to degrade and dissipate faster (Carvalho et al 1992) are little known. In a laboratory model aquarium simulating a tropical marine environment, we studied the persistence and accumulation of HC-chlorpyrifos in sediment, fish and oysters. The results obtained from these studies are reported in this paper. | ||
21 | 2003 | The Identification, Distribution And Impact Of Mineral Imbalances And Disorders In Grazing Livestock. A Case Study In Western Kenya. Click to View Abstract
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22 | 2002 | Quantitative Aspects Of Inorganic Nutrient Fluxes In The Gazi Bay (Kenya): Implications For Coastal Ecosystems. Click to View Abstract Fluxes of dissolved inorganic nutrients: NH+4, NO-2, N-3, PO34 and Si(OH)4 from near shore sediments of Gazi Bay were measured in situ within mangrove, sea grass and coral reef biotopes using benthic flux bell-jar chambers of cross-sectional area 0.066 m2 and volume 0.0132 m3. The objectives were: (1) to determine the influence of benthic fluxes, fluvial discharge and seasonal variations on the nutrient budget in the Bay waters; (2) to determine the effect of tidal and spatial variations on nutrient loads in the water column and (3) to establish the relative importance of the nutrient sources with regard to total community production of the Bay. | ||
23 | 2002 | Accumulation, Distribution And Metabolism Of 14C-1, 1-Trichloro-2, 2- Bis-(p-Chlorophyenly) Ethane (ppDDT) Residues In Model Tropical Marine Ecosystem. Click to View Abstract Accumulation, distribution and metabolism of ring labelled, "C-1,1,1, - trichloro-2,2-bis(p-chlorophenyl)ethane (p,p'-DDT) in a model marine aquatic ecosystem consisting of sea water, sediment, oysters (Isognomonon alatus) and Humbug fish (Dascillus aruanus) were studied in the laboratory. "C-p,p'-DDT distributes rapidly in the ecosystem immediately after application on the water surface with reduction of its concentration in the water phase from 1.18 ng g"1 to 0.71 ng g'after 2 hours and an increase in its content in the sediment and oysters. The bioconcentration factor reached a maximum of 19x 10* in oysters, and 1657 in Humbug fish after 24 hours. The sediment concentration reached 117 ng g"1 after 168 hours from start of application. A peak bioconcentration factor of 111 x 103 was calculated after 120 hours when 0.24 mg kg"1 of '^>p,p'-DDT was maintained through dosing every 24 hours with 0.002 mg kg' of a mixture of labelled and non-labelled pesticide. The rate of depuration of accumulated "C-p,p'-DDT sediment residues was up to 78.3% after 24 hours while oysters lost only 14.0% during the same period. The loss in Humbug fish was only 22.2% in three days. Volatilisation and sorption losses from seawater alone (without sediment/biota) were found to be very high in the range of 73.8 - 91.5% over 24 h for p,p'-DDT in aerated and non-aerated ecosystem. Gas chromatograph and TLC analysis of water, sediment and oyster samples revealed presence of p,p'-DDT and substantial amounts of p,p'-DDE and p,p'-DDD three days after pesticide dosage. | ||
24 | 2002 | The Distribution Of Organochlorine Pesticides In Marine Samples Along The Indian Ocean Coast Of Kenya. Click to View Abstract The concentrations of organochlorine residues of lindane, aldrin, <*- endosulfan, dieldrin, endrin, p,p'-DDE, p,p'-DDD and p,p'-DDT in samples of seawater, sediment, fish and seaweed from different locations along the coast of Kenya are discussed in relation to the geographical location of the sampling sites and potential sources of residue over a period of two years. All sediment samples were found to contain very low levels of organic carbon except those sampled from Sabaki River that had high (4.7%) organic carbon due to greater primary activity. Most of the pesticides residues (112 samples analysed in 1997 and 258 analysed in 1998/99) were detected in fish, water, sediments and seaweed. The concentration of some residues was higher during the wet season than the dry season in 1997, but no marked seasonal variation was observed in 1998/99. Lindane, aldrin, p,p'-DOT and p,p'-DDE were the most frequently observed residues in all samples while «-endosulfan, dieldrin, p,p'-DDD and endrin were either present in low concentrations or absent in most samples. Water samples had the lowest concentrations of residues (range 0.503 - 9.025 ng g'1). Sediments had the second highest levels of pesticides residues with a range of 0.584 - 59.00 ng g'1 while fish lipid content had the highest levels of residues in 1989/99 with p,p'-DDT concentration of 1011 ng g'1 and 418 ng g"1 p,p'-DDD 'mSiganus rivulatus. | ||
25 | 2002 | The Waterbuck Kobus Ellipsipyrmniss Defassa (Ruppel 1835) As An Indicator Of Ecosystem Health In The Central Rift Valley Lake Systems Of Kenya. Click to View Abstract Introduction | ||
26 | 2001 | Chemistry And Its Applications. ISBN 9966 846 247. Click to View Abstract PREFACE | ||
27 | 2001 | Biofuel Availability And Domestic Use Patterns In Kenya Click to View Abstract The annual domestic consumption levels and patterns of various common biofuels in Kenya were surveyed. The main fuelwood sources were farmland trees, indigenous forests, woodlands and timber off-cuts from plantations. In 1997, about 15.4 million tonnes of firewood (air-dried) were consumed and an equivalent of 17.1 million tonnes round wood wet weight (w/w) was converted to charcoal. In the same year, 1.4 million tonnes of a variety of crop residues were also consumed as domestic fuel. Biofuel availability was the major factor influencing the reported annual spatial species use and consumption patterns. Competing demand for the commonly-used tree species (mainly eucalyptus trees) for commercial and other purposes accounts, to a large extent, for the reported dwindling amounts. Communities in various regions have responded by gradually shifting to other available types including those in gazetted forests. Such a response strategy has implications on the long-term spatial and temporal biofuel use patterns. © 2001 Elsevier Science Ltd. All rights reserved. | ||
28 | 2001 | Biofuel Consumption Rates And Patterns In Kenya Click to View Abstract Abstract Keywords: Biofuels; Per capita consumption; Kenya | ||
29 | 2001 | Carbon Monoxide And Nitric Oxide From Biofuel Fires In Kenya. Click to View Abstract Emission ratios (ER) of CO and NO relative to CO2 are reported from real time emission measurements on biofuel fires in Kenya. The experiments were based on available fuels burning in local popular traditional and improved stoves. The mean dCO/dCO2 ratios were 71, 79 and 74 mmol molt-1for firewood, charcoal and agricultural residues, respectively, while the corresponding mean d/NO/d/CO2 ratios for these fuels, in the same order, were 1.8, 2 and 2.2 mmol molt-1, respectively. Whereas stove design characteristics largely influenced the dCO/dCO2 ratios, the fuel nitrogen content was the major factor determining the dCO/dCO2 ratios. The dCO/dCO2 ratio for fuel derived NO is not affected by fire temperature but linearly depend on the fuel nitrogen content. Other important fuel parameters that influenced the observed emission ratio patterns include fuel moisture content, size and volatile matter content in the case of charcoal. In comparison to savanna and forest fires, biofuel fires tend to favour formation of reduced or partially oxidised compounds. It is clear that a change in energy preference up the "energy ladder" leads to a reduction in the CO ER, an important result for emission mitigation policy design. | ||
30 | 2001 | Worker Exposure And Health Risks From Volatile Organic Compounds Utilized In The Paint Manufacturing Industry In Kenya. Click to View Abstract This study provides a means for the evaluation of cleaner manufacturing and the provision of cost-effective worker health improvements in developing nations. Individual worker exposure to volatile organic compounds was measured in the paint manufacturing plants of Nairobi, Kenya. A variety of different paint production jobs were monitored, including laboratory researchers, mixers, tinters, fillers, cleaners, raw materials deliverers, and resins producers. | ||
31 | 2001 | Chemistry And Its Applications Click to View Abstract PREFACE To reap the full benefit of any product available in the market, consumers should know the types of raw materials in the products, the way in which the products perform their job, and the precautions that need to be taken when using the products. With some basic knowledge of chemistry, the small print on the label becomes important to the consumer and may lead to a better selection and use of the product purchased. The first chapter of this book deals primarily with the chemical nature of both living and non-living things. Chapter Two places emphasis on the innate curiosity of man and his use of experimentation in the evolution of important chemical transformation processes that bring about changes in matter. These reaction processes are employed in the chemical industries discussed in the subsequent chapters; their inclusion therefore seeks to bring the study of chemistry into focus in the student's life. The rest of the text material, which can be built on a very thoughtful analysis of chemical theory or a simple notion of atoms, molecules and a few molecular geometries and interactions, enlightens the student on the many ways in which chemical knowledge has been applied to solve practical problems. An innovative approach to the problem of teaching students something about the chemical processes which touch upon their daily lives is discussed under various chemical aspects including: isolation of metals from their ores and salts and their uses, nuclear processes and their applications, the manufacture of soaps and detergents, synthetic fibres and surface-coating products, beauty aids, perfumes and flavouring agents, foods, agrochemical and animal health products, fermentation reaction products and medicines, environmental chemical pollution, chemical poisons and their basis of toxicity, the role of chemistry in industrial and economic development (with a discussion on some critical industries) and, finally, safety precautions against chemical hazards. Although some of the exercises provided at the end of each chapter are meant to test the reader's understanding of concepts, a few open-ended questions have been added to stimulate the bright student and to involve him or her in some of the inevitable controversies of chemical science. A few references have been provided to encourage the enthusiastic student to develop a taste for studying in depth a particular point of interest. | ||
32 | 2000 | Evaluation Of The Trace Mineral Status Of Lactating During Cattle In Trans Nzoia District, Western Kenya. In: A.M. Roussel, R. A. Anderson And E., E. Favier Eds. Click to View Abstract A number of diseases and production problems have been observed in grazing ruminants in many countries around the I world Some of these problems and health effects have been attributed to dietary imbalances in mineral supply and appear \ to be geographically distributed. Grazing cattle require different levels of minerals in their diet depending on the stage of class of development; young and growing, lactating or pregnancy. Common findings indicate that the lactating and young} and growing animals are the most vulnerable to mineral problems, thus providing a sufficient ground for their choice in\ experimental studies. In this preliminary review of the project, the nutritional status of cattle grazing on a range of farms in \ Irons Nzoia District are assessedfrom the mineral content of blood from young and growing as well as lactating animals] sampled during the dry and wet seasons of the study period. Data -will be evaluated in terms of established criteria normality. | ||
33 | 1999 | Environmental Impact Assessment Of The Proposed National Oil Corporation Of Kenya Truck Loading Facility, Industrial Area, Nairobi, Kenya. Click to View Abstract EXECUTIVE SUMMARY | ||
34 | 1999 | Essential Trace Element Analysis Of Traditional Medicines Used In Anticonvulsant Therapy In: M.Adullah, M.Bost, S.Gamon, P. Armand And G. Chazot Eds: Click to View Abstract
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35 | 1999 | Quantitative Aspects Of Inorganic Nutrient Fluxes In Gazi Bay (Kenya): Implications For Nearshore Coastal Ecosystems. Click to View Abstract
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36 | 1998 | Skull Abnormalities In The Waterbuck Kobus Ellipsiprymnus Defassa (Ruppel 1935) In The Rift Valley Lake Systems Of Kenya. Click to View Abstract |7 Skulls of the waterbuck (kobus ellipsiprynnus defassa) ithree lake systems of the central Kenyan Rift Valley (viz. tfakuru, Elementaita and Naivasha) were examined for bnormalities, as a result of chronic signs of ill health, in ome of the animals in the region. The waterbuck were ulled randomly and weighed. Several parameters were leasured. A post mortem examination was carried out on ach of the animals culled. Bone samples were stripped F all tissue by boiling. The skulls were weighed and amined for any abnormalities. The teeth were used for eing the animals. | ||
37 | 1998 | The Energy Sector: A Case Study On Hydropower. In: Climate Change Impacts, Vulnerability And Adaptation. Click to View Abstract Statement of the Problem | ||
38 | 1997 | Non-destructive Analysis Of Mercury By The Energy Dispersive X-ray Fluorescence Technique In Beauty Creams Sold In Kenya. Proc. Int. Click to View Abstract NON-DESTRUCTIVE ANALYSIS OF MERCURY BY THE ENERGY DISPERSIVE X RAY FLUORESCENCE TECHNIQUE IN BEAUTY CREAMS SOLD IN KENYA. | ||
39 | 1997 | Occurrence Of Chlorfenvinvos In Cow's Milk Sampled At A Range Of Sites In Western Kenya. Click to View Abstract Kenya's fast growing human population is expected to reach 35 million by the year 2000. In order to cope with such a rapid rate of growth, efforts must be directed towards adequate agricultural and livestock production to counter the disproportionate increase in demand for food. To provide sufficient animal protein (milk and beef products) attempts must be made to eliminate the current constraints hindering livestock production and expansion in Kenya (KARI,1989). One such constraint (in terms of both health effects and economic losses) is the presence of several important infectious diseases affecting cattle, characterized by the occurrence of parasites in the animal's blood (haemoparasites) (Mutugi et al, 1989). Currently, the most conventional method of controlling ECF and anaplasmosis in cattle involves the use of acaricides. In Western Kenya, many types of acaricides are available but presently, the most commonly used chemical is chlorfenvinphos (ILRAD, 1991). It is frequently applied on cattle either through plunge dips or sprays. Little, however, is known about the fate of this compound and its residual effect in milk and beef. A recent survey in Kenya (KEMRI,1988) suggests that chronic or acute exposure to chlorfenvinphos can result in serious health effects in humans. Residue levels exceeding 8jug/kg of butterfat in cow's milk are currently regarded as dangerous for human consumption (Codex Alimentarius,1993), although concentrations as high as 20/ig/kg have been reported in Australia (Shell, 1969). Correspondence to: I. O. Jumba | ||
40 | 1996 | Effects On Botanical Composition On Mineral Concentrations In Dry Pastures In "Western Kenya. In: Appleton, J.D., Fuge, R. And MaCall, G.J.H. (eds). Click to View Abstract Abstract: The influence of botanical (pasture species), geographical (altitude) and pedological (bedrock type, soil pH and extractable mineral concentration) factors on mineral concentrations in dry season pasture was studied in samples of topsoil and herbage from 135 sites on 84 farms in the Mt Elgon region of western Kenya. Of the four major elements measured in herbage, only S was affected by geology, low values being found above Tertiary volcanic (TV) and metamorphic gneiss (MG) bedrocks. By contrast, only P was not affected by species, Setaria being low and Kikuyu grass usually high in macro minerals. Of the seven trace elements analysed in herbage, geology influenced only one: Cu; low values were again found above TV and MG but Cu availability to grazing ruminants would be relatively high because of the associated low S values. By contrast, only Se was unaffected by species, Kikuyu grass being high in all but Mn. Soil bedrock had a greater influence on soil composition but correlations between extractable soil and herbage mineral concentrations were poor for all elements, even within botanical species after correction for soil pH and soil contamination. Concentrations of Ca, P, Mg, S, Cu and Zn were often less than tabulated requirements for grazing livestock. However, risks of deficiency could not be predicted from the pedological factors measured. | ||
41 | 1996 | Mineral Composition Of Tropical Forages In The Mount Elgon Region Of Kenya. I. Macro-minerals. Click to View Abstract A survey of the macro-mineral concentrations in herbage in the Mt Elgon region of western Kenya is described. A total of 135 samples of dry-season herbage from 84 farms covering 30 000 km2 was analysed for calcium (Ca), phosphorus (P), magnesium (Mg), and sulphur (S). Mean (±standard deviation) concentrations were Ca, 1.5 (0.52); P, 1.4 (0.76); Mg, 1.6 (0.53); S, 1.5 (0.59) g kg'1 dry matter. Calcium, P, and Mg concentrations were low compared with surveys in other tropical countries but this may partly reflect the mature stage at which herb¬age was sampled. Comparisons with recent estimates of the mineral requirements of ruminants indicated that most of the samples were deficient in Ca and P while a minority was deficient in Mg and S. However, such deficits are not synonymous with constraints upon livestock pro¬duction, and supplementation trials with grazing livestock should be conducted. | ||
42 | 1996 | Mineral Composition Of Tropical Forages In The Mount Elgon Region Of Kenya. II. Trace Elements. Click to View Abstract A survey of trace mineral concentrations in herbage in the Mt Elgon region of western Kenya is described. A total of 135 samples of mature herbage from 84 farms covering 30 000 km2 was analysed for cobalt (Co), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), sele¬nium (Se), and zinc (Zn). Mean (±standard deviation) concentrations [mg kg'1 dry matter (DM)] were Co, 0.2 (0.16); Cu, 4.0 (1.6); Fe, 300 (169); Mn, 220 (128); Mo, 1.1 (0.23); Se, 0.1 (0.03); Zn, 23.6 (9.4). Copper and Zn concentrations were low compared with surveys in other tropical countries but this may partly reflect the mature stage at which herbage was sampled. Comparisons with recent estimates of the mineral requirements of ruminants indicated that most of the samples were deficient in Cu. A minority of the pastures contained less Se and Zn than ruminants are thought to require, but deficiencies of Co, Fe, and Mn were rare. Iron may be more significant as an antagonist of Cu but Mo rarely reached concentrations high enough to be antagonistic to Cu. The possibility of constraints upon livestock production should be inves¬tigated by supplementation trials with grazing livestock beginning with Cu. | ||
43 | 1996 | Evaluation Of The Mineral Status Of Grazing Cattle In Trans Nzoia: Preliminary Assessment Of Data. Proc. Click to View Abstract Abstract | ||
44 | 1996 | SENSITIVITY OF KENYAN ECOSYSTEMS TO ACIDIC DEPOSITION: VALIDATION OF THE 1996 SEI MAP Click to View Abstract SUMMARY | ||
45 | 1995 | Effects Of Soil Origin And Mineral Composition Of Herbage Species On The Mineral Composition Of Forages In The Mount Elgon Region Of Kenya I. Calcium, Phosphorus, Magnesium And Sulphur. Click to View Abstract Samples of topsoil (0-30 cm) and dry season herbage from 135 sites in the Mt Elgon region of Kenya were classified according to farm (n = 84), site altitude, underlying soil bedrock (6 types) and botanical composition (6 classes). Effects on pasture concentrations of Ca, P, Mg and S were determined using a mixed model for unbalanced data sets and the Wald (W) statistic to assess the significance of fixed effects. Associated effects on pH, plus extractable Ca and P concentrations in the topsoils were also evaluated. | ||
46 | 1995 | Effects Of Soil Origin And Mineral Composition And Herbage Species On The Mineral Composition Of Forages In The Mount Elgon Region Of Kenya. 2. Trace Elements Click to View Abstract Samples of topsoil and herbage from 135 sites in the Mt Elgon region of Kenya were classified according to farm, site altitude, underlying soil bedrock (6 types) and botanical composition (6 classes). Effects of altitude, bedrock and species on pasture concentrations of Co, Cu, Fe, Mn, Mo, Se and Zn were determined using a mixed model for unbalanced data sets and the Wald statistic (W) to assess statistical significance. Extractable concentrations of each element in the soil were measured at each site except for Se where total Se was used. | ||
47 | 1995 | IGBP KENYA TASK TEAM. Coastal Pollution In Implication Of The Expected Climate Change On Some Selected Low-Lying Coastal Parts Of Kenya. A Case Study In Tourism And Hotel Industry. Click to View Abstract
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48 | 1994 | IGBP Kenya Task Team. Implications Of Sea Level Rise In Some Areas Of Kenyan Coast.The National Committee For International Geosphere Biosphere Programme Standing Committee Of The Kenya National Academy Of Sciences Click to View Abstract
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49 | 1994 | Status Of Some Trace Elements In Waterbuck (Kobus Ellypsiprymnus Defassa) In Relation To Soil And Forage Composition And Implications For Animal Health In Lake Nakuru Park. Click to View Abstract
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50 | 1993 | Macro And Trace Element Composition Of Forages In Western Kenya: Implications For Sheep And Cattle Health And Production. Click to View Abstract ABSTRACT | ||
51 | 1993 | Botanical Composition Has A Greater Influence On Mineral Concentrations In Dry Season Pastures In W. Kenya Than Either Soil Origin Or Composition. Click to View Abstract The prediction of mineral deficiencies in grazing livestock requires good correlations between convenient markers of mineral status and animal health or productivity. Correlations are likely to become weaker in moving from animal to pasture to soil in pursuit of a predictor because of the many factors which influence mineral uptake at each interface. However, soils are the easiest to characterize and correlations might be improved by removing the effects of known sources of variation. The influence of botanical (pasture species), geographical (altitude) and pedological (bedrock type, soil pH and extractable mineral concentration) factors on mineral concentrations in dry season pasture was therefore assessed. Samples of topsoil and herbage were gathered from 135 sites on 84 farms in the Mt Elgon region of W. Kenya between January and March, 1987. The underlying parent bedrock was determined from 1:125,000 Geological survey maps and altitude from topographical maps. Botanical composition of the pasture sample was recorded. Soil pH and total (Se) or extractable (not Se) mineral concentrations were determined by standard methods as were total mineral concentrations in unwashed herbage. Distribution of principle botanical species and all bedrock types amongst the sample sites are indicated in Tables 1 and 2 respectively, together with the analytical results. Statistical analysis used a residual maximum likelihood (REML) model for unbalanced data sets. | ||
52 | 1992 | Assessing The Incidence And Prevalence Of Mineral Imbalances In Grazing Livestock In The Tropics: A Case Study In Western Kenya Click to View Abstract
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53 | 1990 | Levels Of Aluminium In Green Leaf Of Clonala Teas, Black Tea And Black Tea Liquors And Effects Of Rates Of Nitrogen Fertilizers On The Aluminium Black Tea Contents. Click to View Abstract Clonal teas have different aluminium content increasing with age of leaf. Although aluminium andfertilizernitrogen enhance teagrowth andteayields, respectively, field trials have shown no relationship between total aluminium content in the leaf and clonal tea yields. Higher aluminium concentrations were found in the dust grades of black tea than in the large size grades. However, aluminium levels decreased in the tea liquor from dust grades compared to the large size grades. Only up to 40% of the total aluminium in tea was infused into tea liquors; the amounts infused varied with clones and grading (sorting). Aluminium content of black tea was lowered by increasing rates of nitrogenous fertilizers, more frequent fertilizer application, and application of NPK 20:10:10 as opposed to NPKS 25:5:5:5. | ||
54 | 1982 | The Determination Of Mercury In Body Beauty Soaps And Creams Sold In Kenya And Norway. Click to View Abstract flame-less atomic absorption spcctropholometry technique lias been used to determine mercury concentrations in 14 skin-lightening creams and soaps commonly sold in the Kenyan market and 10 in the Norwegian market. The use of borohydride or stannous chloride as the reducing agents for mercuric salts gave different results. When slannous chloride was used as the reducing agent the range of mercury content was 222 to 4920 jjg/kg. When borohydride was used as the reducing agent the range of mercury content was 0.95 to 1121.86 |jg/kg. The difference in results has been attributed to the difference in digestion modes and the ability of the boric acid to encapsulate the mercuric salts. In general the Kenya products had slightly higher mercury content. | ||
55 | 1982 | Factors Affecting The Simultaneous Determination Of Cooper, Lead, Cadmium And Zinc Concentrations In Human Head Hair Using Different Pulse Anodic Stripping Voltametry Method. Click to View Abstract Conditions of analyses of copper, lead, cadmium and zinc content in human hair using differential pulse anodic stripping voltammetry (DPASV) and hanging mercury drop electrode (HMDE) have been established. Sample digestion using the mixture HC1; H2O2:HNO3 in the ratio 2:1:40 by volume gave the best wet-ashing procedure. The peak currents and peak potentials of zinc, cadmium and lead, copper were maximum at pH 6-7 and 1-3 respectively, when excess H2O2 was eliminated with subsequent addition of hydroxyamine hydrochloride. Matrix concentration effects were minimized by digesting weights not exceeding 50 mg per sample. The effect of selenium (IV) was negligible and was ignored. The detection limit of 0.0036 ng/cm3 for Cd+2 was obtained while the values for zinc, lead and copper were 0.0230, 0.0287 and 0.0269 ng/cm3 respectively, at the 95% confidence limit. The observed DPASV conditions of analysis of these metals are useful for routine determination of the metals in human hair and should complement the conventional flame atomic absorption spectrophoto-metry methods | ||
56 | 1982 | The Concentrations Of Heavy Metals, Zinc, Cadmium, Lead, Copper, Mercury, Iron And Calcium Concentrations In Human Head Hair Of A Randomly Selected Sample Of Kenyan People. Click to View Abstract SUMMARY | ||
57 | 1980 | Factors Affecting The Determination Of Lead, Cadmium, Copper And Zinc Content In Hair Using Differential Pulse Anodic Stripping Voltammetry And Flame Atomic Absorption Spectroscopy Click to View Abstract
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