DETERMINATION OF LEVELS OF ORGANOPHOSPHORUS PESTICIDE RESIDUES IN KALES, TOMATOES AND FRENCH BEANS FROM MERU COUNTY, KENYA BY GC-MS
Abstract
Purpose of the Study: The aim of this study was to investigate the levels of pesticides and metabolites in kales, tomatoes and French beans from Imenti North, Imenti South and Buuri Sub County in Meru County, Kenya.
Statement of the Problem: Pesticides are known to be the most important tool for the production of adequate food supply for an increasing world population and for the control of vector-borne diseases. However, pesticides have some toxicological and environmental consequences, which include toxic residues in food substances and adverse effects on non-target organisms. The gross and improper use of synthetic pesticides is a matter of much concern. Pesticides have been associated with a wide variety of human health hazards, ranging from acute impacts such as headache, vomiting and diarrhoea to chronic impacts like cancer, reproductive harm and endocrine disruption. Many people die from pesticides poisoning and other people suffer from various health effects.
Research Methodology: Samples of fresh kales, tomatoes and French beans from the farm were analyzed for pesticide residues. Extraction was performed using acetone followed by dichloromethane: cyclohexane mixture and the extracts were cleaned up using Florisil. The compounds were determined by gas chromatography-mass spectrometry (GC-MS). Pesticides and metabolites were detected in 72.2% of the samples.
Study Results: The detected pesticide residues and their highest mean concentrations were Azoxystrobin,15.93±1.48µg/Kg, diazinon 0.15±0.0048µg/Kg, Cabendazim 48.65±3.5848µg/Kg, imidacloprid290.76±26.3448µg/Kg,acetamiprid2.49±0.0648µg/Kg,metalaxyl 105.18±6.3248µg/Kg and chlorpyrifos 3.83±0.0048µg/Kg. Generally, there were no significant variations in concentrations of pesticide residues among samples and sampling sites, which indicated similarities in contamination patterns. The concentrations of contaminants were below the maximum residue limits (MRLs) in all of the samples.
Conclusion: The co-occurrence of pesticide residues in samples was due to various reasons including mixing of pesticides by farmers during application as farmers use more than one pesticide at one time due to resistance of pests.
Key Words: Organophosphorus, Pesticide, Residues, Kales, Tomatoes, French Beans
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