Browsing by Author "Wanjau, Ruth N."

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    Analysis of Deltamethrin Residue Amounts Using HPLC in Some Vegetables Consumed in a Rural Area - Makuyu, Kenya
    (Globeedu Group, 2014) Kithure, Joyce G.N.; Murungi, Jane I.; Wanjau, Ruth N.; Thoruwa, Caroline L.
    Vegetables are brimming with fibre, plus a whole range of vitamins and minerals, and because they are low in calories, they make an important and healthy addition to any diet. Scientific studies have shown that people who eat a lot of vegetables may have a lower risk of getting illnesses, such as heart disease and some cancers. For this reason, health authorities recommend that you eat at least five portions of fruit and vegetables every day. Pests, diseases, and weeds destroy vegetables reducing their yield and causing blemish thus making them unfit for sale and consumption. Pesticides maintain the high levels of vegetable production in Kenya. There are many pesticides in use today including; insecticides, acaricides, nematocides, herbicides, and avicides. Pyrethroids are the most commonly used insecticides. The pyrethroids in use include; deltamethrin, lambda-cyhalothrin and chismethrin. However, although vegetables are widely consumed by almost everybody in Kenya, there is little work reported on the analysis of pesticides residues in vegetables. Most of the vegetables are grown in the rural areas, with most farmers growing them on small-scale and hence these vegetables never the reach cities. In this study deltamethrin was analysed in selected vegetables which include; kales, cabbages and tomatoes grown I rural area during the dry and wet seasons. The vegetables were bought from different sellers in Makuyu market. They were then homogenized to give analytical samples. Deltamethrin residues were extracted from the samples using organic solvents. The residues were then determined using high performance liquid chromatography (HPLC). Analyses of data was done using ANOVA, t-test and regression analysis. The deltamethrin mean residue levels ranged between 0.0800±0.1300 and 0.1400±0.0800 mg/kg during the dry season and between 0.00120.0016 and 0.1100±0.0080 mg/kg during the wet season. The study showed that deltamethrin mean residue levels were higher during the dry than during the wet season in the vegetables analysed. The differences were not statistically different for most of them. During the dry season the deltamethrin mean residue levels in the vegetable samples were all higher than the Acceptable Daily Intake (ADI) of 0.02 mg/kg, but they were all lower than the Maximum Residue Levels (MRLs) of 0.2 mg/kg. During the wet season the deltamethrin mean residue levels were lower than the ADI except in kale samples. During the same wet season the deltamethrin mean residue levels were all lower than the MRLs.
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    Analysis of Physico-Chemical Parameters and Selected Heavy Metals in Aquatic Ecosystems.
    (IOSR-JAC, 2023-09) MunenePaul M.; Mbugua, Gerald W.; Wanjau, Ruth N.; Ndiritu, N. James
    The quality of aquatic ecosystems is of great concern. Elevation of pollutants in water could cause health disorders in human and destabilize the aquatic ecosystem. The case study investigated quality of water from five sites of Lake Turkana selected based on proximity to potential anthropogenic pollution sources. Temperature, pH, electrical conductivity (EC), dissolved oxygen (DO), salinity, total dissolved solids (TDS) and OxidationReduction Potential (ORP) were measured at the site using YSI Pro 1030 Multiparameter electrode while nitrates and phosphates were determined at Kenyatta University’s food science laboratory using Vis 130 Spectrophotometer. Selected heavy metals (lead, cadmium and chromium) were determined using flame atomic absorption spectroscopy. Sampling was performed in triplicates during the dry season. The results were: temperature (28.24±0.96 to 28.86±0.38°C), pH (9.04±0.21 to 9.46±0.06), electrical conductivity (281.57±0.41 to 289.46±3.95 Ωcm-1 ), dissolved oxygen (6.3±0.79 to 7.04±0.05 mg/L), salinity (1.67±0.00 to 1.70±0.01 ppt), TDS (2093.4±0.39 to 2135.8±4.86 mg/L), ORP (-54.22±0.12 to 588.14±0.51 mV), nitrates (5.52±0.31 to 10.04±1.82 mg/L) and phosphates (0.47±0.06 to 0.72±0.15 mg/L). Water lead (0.11±0.01 to 0.12±0.00 mg/L), cadmium (0.00±0.00 to 0.03±0.00 mg/L) and chromium (0.01±0.00 to 0.03±0.01 mg/L). The results showed that pH and TDS were beyond WHO standard of 6.5-8.5 and 600.0 mg/L respectively while phosphates exceeded USEPA limit of 0.024 mg/L in all sites. The electrical conductivity and nitrates complied with WHO standards of 400.0 Ωcm-1 and 50.0 mg/L respectively while the other parameters were not guided by WHO. The lead levels in water exceeded WHO standard of 0.01 mg/L in all sites. The cadmium levels in Impressa and Long’ech beaches in the upstream section exceeded WHO standard of 0.003 mg/L. However, chromium complied with WHO standard of 0.05 mg/L in all sites. These calls for measures keep all the parameters under surveillance to ensure water quality is maintained.
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    Clarification of colloidal and suspended material in water using triethanolamine modified maize tassels
    (Springerlink, 2015) Kinyua, Esther Mbuci; Mwangi, Isaac W.; Wanjau, Ruth N.; Ngila, J.C.
    Suspended particles in water are a major concern in global pollution management. They affect the appreciation of water due to clarity, photosynthesis, and poor oxygen environment rendering water unsuitable for aquatic animals. Some suspended materials contain functional groups capable of forming complex compounds with metals making them available for poisoning. Such material promotes the growth of bacteria and fouling that give rise to unpleasant taste and odor of the water and thus requires removal. Removal of suspended solids is normally achieved through sedimentation or filtration. However, some suspended colloidal particles are very stable in water and cannot settle while others are able to pass through the filter due to small size, hence difficult to remove. This study investigated the use of triethanolamine-modified maize tassels to form a flocculent for their removal. The modified maize tassels were characterized using Fourier transform infrared (FTIR), and it was found that the triethanolamine was anchored within the cellulose structure of the maize tassels. Clarification parameters such as settling time, reagent dosage, and pH were investigated. The best clarification was at a pH of 6.0 with clearance being less than in 30 min. The optimal flocculent dosage was found to be 3.5 ml of the material, showing that the material has a potential of enhancing clarity in polluted water
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    A Comparative Study of Modified and Unmodified Algae (Pediastrum boryanum) for Removal of Lead, Cadmium and Copper in Contaminated Water
    (INTECH, 2017) Joseph, John Okapes; Mwangi, Isaac W.; Swaleh, Sauda; Wanjau, Ruth N.; Ram, Manohar; Ngila, Jane Catherine
    The presence of heavy metals in water is of concern due to the risk toxicity. Thus there is need for their removal for the safety of consumers. Methods applied for removal of heavy metals include adsorption, membrane filtration and co-precipitation. However, studies have revealed adsorption is highly effective technique. Most adsorbents are expensive or require extensive processing before use and hence need to explore for possible sources of inexpensive adsorbents. This research work investigated the use an algal biomass (pediastrum boryanum) as an adsorbent for removal of Lead, Cadmium and Copper in waste water in its raw and modified forms. The samples were characterized with FTIR and was confirmed a successful modification with tetramethylethlynediamine (TMEDA). Sorption parameters were optimized and the material was finally applied on real water samples. It was found that the sorption was best at lower pH values (4.2-6.8). Sorption kinetics was very high as more that 90% of the metals were removed from the solution within 30 minutes. The adsorption of copper fitted into the Langmuir adsorption isotherm indicating a monolayer binding mechanism. Cadmium and lead fiĴed best the Freundlich adsorption mechanism. Sorption of lead and cadmium was of pseudo-second order kinetics, confirming a multisite interaction whereas copper was pseudoȬfirst order indicating a single site adsorption. The adsorption capacity did not improve upon modification but the stability of the material was improved and secondary pollution of leaching colour was alleviated. This implies that the modified material is suitable for application on the removal of metals from water.
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    Levels of Iodide, fluoride and Chloride in Amaranth grain in Kenya
    (International Organization of Scientific Research, 2016) Kipngetich, Tonui M.; Wanjau, Ruth N.; Gikonyo, Nicholas K.; Murungi, Jane
    The levels of chloride (Cl-), fluoride (F-) and iodide (I-), in amaranth (Amaranthus hypochondriacus and Amaranthus cruentus) leaves at different stages of maturity (25 days, 50 days and 75 days) and seeds from four counties (Kiambu, Kericho, Bungoma and Kisii) of Kenya were quantitatively determined. The levels were determined using potentiometric and titrimetric methods. The mean levels of Cl-, F- and I- in leaves of A. hypochondriacus and A. cruentus were not significantly different. The mean levels in leaves of the two species indicated that amaranthus grown in Kiambu had Cl- and F- at 673.81 and 7.61 mg/100 g respectively while I- was at 4.29 mg/ kg. Leaves from amaranthus grown in Kericho county had mean levels of Cl- and F- of 635.24 and 7.22 mg/100 g dry weight, respectively while I- was 3.41 mg/kg. The mean I- level in amaranth leaves grown in Bungoma was 2.54 mg/kg while Cl- and F- were 503.74 and 9.67 mg/100 g respectively. The mean Cl- and F- level in leaves from Kisii were 595.54 and 8.96 mg/100 g of dry weight respectively, while the mean I- level was 5.26 mg/kg dry weight. Samples of leaves collected in the dry season and in dry season were also accessedThe levels of all inorganic anions determined were found to be within the allowed daily intake (ADI) values. Based on the results of this study, it is recommended that leaves and grains from both species of amaranthus grown in most regions in Kenya may be consumed for nutritional requirements. The consumption of between 250 g and 300 g of fresh amaranthus leaves is sufficient to provide the required daily intake of all the anions considered in this study for all healthy individuals.
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    Remediation of Fluoride Laden Water by Complexation with Triethylamine Modified Maize Tassels
    (Canadian Center of Science and Education, 2016) Mwangi, Charles K.; Mwangi, Isaac W.; Wanjau, Ruth N.; Swaleh, Sauda; Ram, Manohar; Ngila, J.C.
    Several methods for the removal of fluorides in water have been proposed, most of which rely on the use of biomaterials and bone char. In such processes, the adsorbent become loaded with the pre-concentrated pollutant leading to a disposal problem. This study reports on the modification of the maize tassels with triethylamine followed by its subsequent application on the removal of fluoride ions from water. The theory underlying the removal method is based on the interaction of the permanently charged quaternized material with the highly electronegative fluoride ion. This is a regeneratable, affordable, eco-friendly, solution to the problem of secondary pollution and sustainable water remediation method of this toxic water pollutant. The resulting biomaterial derived from agricultural waste was used in the removal experiments on both model solutions and real water samples. The effect of pH, contact time, initial fluoride concentration and biomaterial resin dosage were investigated. It was observed that the amount complexed fluoride ions per unit mass of biomaterial increased with increase in concentration up to a point of saturation. The optimum removal pH was found to be 4.0. The biomaterial was very effective in fluoride removal as 86% of the fluoride was removed within the first 20 min. However, the uptake of fluoride ions in real water samples was found to be slightly lower compared to the model solutions. The experimental data was analysed using Langmuir and Freundlich isotherms. It fitted best in the Langmuir isotherm implying a chemisorption process. The adsorption capacity was found to be 0.19 mg/g and it was also observed that the sorbent when packed in a SPE column could be regenerated by stripping the attached fluoride ions with a dilute hydrochloric acid solution. These findings show that the modified material is suitable for application in the removal of fluorides in water at a point of use. This is intended to offer a solution to the drinking water for the children born by the population living in areas that are naturally fluoridated. Such parents are mean with their smile due to the problem of their permanently brown stained teeth.
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    Remediation of lead, cadmium and copper polluted waters by onion skins (Allium Cepa)
    (International Journal of Agriculture Innovations and Research, 2016) Waweru, Beatrice W.; Mwangi, Isaac W.; Murungi, Jane; Wanjau, Ruth N.; Msagati, T.A.M.; Manohah, Ram
    The chemical structure of water makes it have special properties due to lopsided electrical charge that enable water to be a solvent for ionic compounds. That dissolving power is very important for life and has contributed to 97 % of the world’s water being salty. As water interacts with the environmental matrix, it dissolves ionic material at different concentrations which may render this vital commodity polluted with dissolved matter of both organic and inorganic origin. Presence of heavy metals in water is a worldwide environmental concern due to pollution. Therefore, there is need to find a sustainable and affordable method to remove such pollutants from water to render it safe. This study investigated the sorption efficiency and mechanism of onionskin in both their raw and modified forms on the removal of lead, copper and cadmium in aqueous media. The modification of the study material was done by anchoring ethylene-1, 2-diamine (EDA) within the structure of the onionskins. This was anticipated to improve the quality of the adsorbent material for application on the removal process. Sorption parameters were optimized and the respective optimal values applied. Experimental results confirmed that best sorption pH range for the metals was ranging between 4.0 -6.0 which is within the physiological pH of water. It was also realized that the sorbent material could remove 90 % of the metals within the first 20 minutes of contact. The experimental data was analysed using Freundlich and Langmuir adsorption isotherms and found out that the three metal ions fitted best in Langmuir model. However, the unmodified onionskin leached soluble organic substances in the form of colour and smell thus causing a secondary pollution. This was overcome by modification of the material. The sorption capacities for lead, cadmium and copper were found to be 71.85, 68.03 and 79.36 mg g-1 in the modified sorbent material respectively and 87.49, 96.99 and 90.8 mg g-1 in the same order for the unmodified form. Despite the sorption capacity not improving, the effect of secondary pollution was minimized from 15.1 mg L-1 to 7.9 mg L-1 thus improving the quality of the sorbent material. The resulting material was then applied on environmental water samples whose concentration was determined and thereafter spiked with lead, cadmium and copper ions of varying concentration. The maximum percent recoveries were determined as 87.8±0.01%, 80.6±0.01% and 77.1±% for lead, cadmium and copper ions respectively. This indicated that the material which initially had no useful purpose with disposal problems has potential application for remediation of metal laden waters
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    Remediation of some selected heavy metals from water using modified and unmodified mushrooms
    (2016) Bii, Arap Thomas; Mwangi, Isaac W.; Wanjau, Ruth N.; Swaleh, Sauda; Manohar, Ram; Ngila, JC
    The dispersal of toxic heavy metals by water from natural and anthropogenic is a worldwide environmental concern due to pollution. Despite some metals playing an important role in body, they are toxic when the level exceeds the tolerance limits while others such as lead have no known physiological value to human beings. Since heavy metals cannot be degraded, then their removal from drinking water is necessary. Mushrooms are readily available in Bomet County and their metal removal ability was investigated. The study aimed at removing heavy metals from water by adsorption using mushroom, as a cost-effective and sustainable method. The raw mushroom was modified with sodium hydroxide and characterization of both the parent material and its modified form was done using Fourier Transform Infrared spectrometry (FTIR). Sorption experiments were carried out using the batch adsorption method and sorption parameters including pH, contact time, adsorbent dose and initial metal ion concentration investigated. The results found out that the sorption capacity for cadmium ions ranged from 1.826- 25.285 mg/g by the unmodified edible mushroom (UEM), the modified edible mushroom (EM), unmodified toxic mushroom (UTM) and modified toxic mushroom (TM). For copper ions, sorption capacity ranged from 0.002-4.097 mg/g, while that of the lead ions ranged from 1.345-2.593 mg/g by the UEM, EM, UTM and TM respectively. The sorption capacity showed improvement on modification as sorption of cadmium increased from 1.826-25.285 mg/g by the UEM, EM, UTM and TM. At a pH range of 4-6, the sorbent material was found to remove up to 90% of the metals. The sorbent material had a removal efficiency of 95% of the metals in less than 20 minutes. The UEM and UTM fitted well in Langmuir adsorption isotherm model for cadmium and lead ions. For copper ions, UEM, EM, UTM and TM fitted in the Freundlich model. TM for lead ions best fitted in the Freundlich model. The bio-sorption kinetics was determined by fitting first-order-Lagergreg and Pseudo-second-order kinetics models to the experimental data. It was found that the data for lead was better described by the pseudo-second-order model. For copper ion, the data was best described by Ho’s pseudo second order for UEM and UTM, cadmium ions for all sorbents was best described by Lagergreg’s first-order kinetics. The FTIR analysis suggested the possibility of the participation of carboxyl groups in metal uptake. The levels of dissolved organic carbon (DOC) were found to be 19.0 mg/L in the raw material and 2.19 mg/L after modification. It was confirmed that modification minimized secondary pollution. This indicated that mushrooms have a potential application for the remediation of metal polluted waters. Keywords: Mushrooms; Alkali modification; Sorption; Dissolved organic carbon