Persistence and Influence of Selected Pesticides on Cottonseed and its Products

Abstract

Two successive field experiments were carried out during the seasons 2000/01 and 2001/02, to investigate the persistence and influence of the insecticides chlorpyrifos, demeton-s-methyl, omethoate and malathion on cottonseeds of Barakat-90 and Barac-67 cultivars. The analysis of the results showed that, no pesticides residues were detected in cottonseeds harvested from plant treated with the insecticides chlorpyrifos, demeton-s-methyl, and malathion at their different levels, for both Barakat and Barac cultivars. However, for omethoate, detectable residues were observed in Barakat cultivar, at the second level in both seasons. The detected levels were 2.5 mg/Kg and 0.4 mg/Kg for the first and the second season respectively. Significant (P ≤ 0.05) increase in cottonseed oil was observed in seeds of Barakat as influenced by different insecticides treatments, while no significant difference was noted in Barac. Protein content increased significantly in cottonseeds in both cultivars with all treatments. In contrast, significant (P ≤ 0.05) reduction in tannins content was observed in both as influenced by different application of these pesticides, while no significant change was observed in phytic acid content. The change in ash minerals of cottonseeds of both cultivars showed no consistent patterns as influence by different pesticides treatments. 6 The results also showed that application of these pesticides increased seed index of cultivar Barakat, while for Barac cultivar, slight but non-significant difference was observed. However, for seed germination results indicated that application of pesticides did not suppress the germination of cottonseeds of both cultivars. Crude oil of cottonseed was spiked with insecticides endosulfan and demeton-s-methyl, and was subjected to different processes of refining, under laboratory conditions. The insecticides levels were determined immediately after processing. The results indicated the absence of detectable levels of these insecticides by the refining process. Breakdown products were not identified and should be addressed in future work.