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dc.contributor.authorNjagi, G. J.
dc.date.accessioned2011-12-14T12:33:03Z
dc.date.available2011-12-14T12:33:03Z
dc.date.issued2011-12-14
dc.identifier.urihttp://ir-library.ku.ac.ke/handle/123456789/1988
dc.descriptionDepartment of Chemistry, 120p. 2006. The TX 571.P4N52en_US
dc.description.abstractVegetables are considered a cheaper source of natural nutrients. They are therefore widely consumed and they play a vital role by providing vitamins and minerals in the diet, besides supplying protein and energy. These nutrients from vegetables help to overcome common disorder like anemia, deficiency disorders and other ailments in human beings. Vegetables are also very important in neutralizing the acids produced during digestion and also useful as roughage. However, pests, diseases, and weeds destroy vegetables. There are many chemicals with which they can be controlled, including pesticides. Among the insecticides used are the pyrethroids which include; deltamethrin, lambda-cyhalothrin and chismethrin. Most of these chemicals are poisonous to creatures besides those they are intended to kill. There is need, therefore for monitoring the pesticides residues because they can be injurious to the life of human beings, animals, fish, and birds. Although, vegetables are widely consumed by almost everybody in Kenya, there is little work done on the analysis of pesticides residues in the vegetables. In this study deltamethrin and lambda-cyhalothrin were analysed because they are the most commonly used pesticides on vegetables. Vegetable samples were bought from both urban and rural areas. Pesticide residues were extracted from the samples using organic solvents. The residues were then determined by high performance liquid chromatography. The study showed that, during the dry season there were higher levels of deltamethrin and lambda-cyhalothrin in vegetables than during the wet season in all the samples analysed from both urban and rural areas. This probably is due to wash off effect of the pesticides by the rainwater. Another reason could be probably some farmers rarely apply pesticides on vegetables during the wet seasons because there normally few pests than during the dry seasons. In this case the mean residue levels ranged between 0.0130 and 0.3400 mg/kg during the dry seasons and between non detectable level and 0.1100 mg/kg during the wet season. The differences in levels of the pyrethroids during the dry and wet seasons were significantly different at 95 confidence limits. It was also found that the vegetables consumed in the urban areas contained higher mean residue levels of deltamethrin and lambda-cyhalothrin than those consumed in the rural areas during the dry and wet seasons. Most of the vegetables consumed in the urban areas are obtained from large-scale farms in the rural areas. The farmers of these large-scale farms therefore, may not have waited for the elapse time before harvesting their vegetables. May be they did not follow the application instructions recommended for the pesticides. The mean residue levels in this case ranged between non-detectable level and 0.3400 mg/kg in the samples analysed from the urban areas and between 0.0012 and 0.1100 mg/kg in the samples analysed from the rural areas. The mean residue levels of kale samples from an experimental garden that were analysed in this study, decreased between day one and day five after the application of the pesticides as a result of degradation and wash off effect. However, most of the vegetable samples analysed in this study had the two pesticides' residue levels exceeding the ADI (acceptable daily intake) although most of them were less than the MRLs (maximum residue limits). This means that those who feed on large amount of vegetables daily may be exposed to high levels of pesticide residues even though the elapse time was waited upon harvesting. Therefore, alternative methods to pesticides use on vegetables may be used like; the biological control of pests or the use of botanical pesticides.en_US
dc.description.sponsorshipKenyatta Universityen_US
dc.language.isoenen_US
dc.subjectPesticide residues in fooden_US
dc.titleAnalysis of Deltamethrin and Lambda-cyhalothrin Pestcide Residues in Selected Vegetables from Urban and Rural Areas in Kenyaen_US
dc.typeThesisen_US


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