Research Article
Endosulfan Pesticide Dissipation and Residue Levels in Khat and Onion in a Sub-humid Region of Ethiopia
@INPROCEEDINGS{10.1007/978-3-030-43690-2_2, author={Feleke Sishu and Elsabeth Thegaye and Petra Schmitter and Nigus Habtu and Seifu Tilahun and Tammo Steenhuis}, title={Endosulfan Pesticide Dissipation and Residue Levels in Khat and Onion in a Sub-humid Region of Ethiopia}, proceedings={Advances of Science and Technology. 7th EAI International Conference, ICAST 2019, Bahir Dar, Ethiopia, August 2--4, 2019, Proceedings}, proceedings_a={ICAST}, year={2020}, month={6}, keywords={Pesticide Endosulfan Dissipation Residue Khat Onion Ethiopia East Africa Sub-humid tropical}, doi={10.1007/978-3-030-43690-2_2} }- Feleke Sishu
Elsabeth Thegaye
Petra Schmitter
Nigus Habtu
Seifu Tilahun
Tammo Steenhuis
Year: 2020
Endosulfan Pesticide Dissipation and Residue Levels in Khat and Onion in a Sub-humid Region of Ethiopia
ICAST
Springer
DOI: 10.1007/978-3-030-43690-2_2
Abstract
Endosulfan, a mixture of α- and β-isomers, is used by farmers in the wet and dry season for khat and onion production. Khat leaf samples were collected in farmer fields at intervals of 1 h; 1, 5, 9 and 14 d after application. The dissipation rate of α- and β-isomers and residue level in khat were compared with residue levels in onion. The extraction was done by using Quick Easy Cheap Effective Rugged and Safe (QuEChERS) method and analyzed by Gas Chromatography – Electron Capture Detector (GC-ECD). Greater residue α- and β-isomer endosulfan levels were found in khat compared to onion as khat leaves are sprayed repeatedly in two week. Residue levels of khat exceeded the tolerable EU limit of 0.05 mg.kg for leafy vegetables and herbs. For both raw and processed onion sample α- and β-endosulfan residues level were below the tolerable of limit EU regulation for bulb vegetables (i.e. 0. 1 mg.kg). The mean half-life for the α-isomer of endosulfan was 3.4 d in the wet season and 3.6 d in the dry season whilst that for the β-isomer was 5.0 d and 5.4 d respectively. Both isomers dissipated fastest in the wet season under conditions of high humidity and precipitation. The β-isomer persisted longer and had a lower dissipation rate from plants surface compared to the α-isomer.