EXTRACTION AND PHOTODEGRADATION OF FENITROTHION ON PLANT SURFACES

Authors: *Ukpebor J.E, Ukpebor E.E

DOI Info: N/A

ABSTRACT

In order to carry out risk assessments for the use of pesticides, it is necessary to understand the fate of the pesticide within the environment. The degradation on leaves is highly important because it is the first surface which the pesticide comes into contact with and from which the pesticide spreads to the wider environment. The aim of this study was to investigate the degradation of fenitrothion, an organophosphorus insecticide used widely in agriculture. Firstly a suitable extraction method was developed, followed by experiments in a solar simulator to determine the half-life of fenitrothion on lettuce (Lactuca sativa), cabbage “greyhound” (Brassica oleracea sabauda) and cabbage “goldenacre” (Brassica oleracea sabauda). The reproducibility of the method was checked. It was found the best method of extraction was sonicating the leaf in 10 mL of methanol for 10 seconds. The half-lives of fenitrothion on lettuce, cabbage “greyhound” and cabbage “goldenacre” were found to be 7.7±0.7 hrs, 2.1± 0.2 hrs and 3.9±1 hrs respectively. Repetition of the extraction method confirmed the reproducibility of the experiments with a coefficient of variation ranging from 2.5 % to 10.6 %. This research is relevant in determining the extent of pesticide residues on fruit surfaces after post- harvest application.

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