title: Determination of Levels of Organochlorine, Organophosphorus, and Pyrethroid Pesticide Residues in Vegetables from Markets in Dar es Salaam by GC-MS.
abstract: This study investigated the levels of pesticides and metabolites in vegetables from major markets in Dar es Salaam city, Tanzania. Samples of fresh cabbage, spinach, and onions from the markets were analysed 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. The detected pesticide residues and their highest mean concentrations werep,p'-DDT 4.00 × 10-3mg/kg,p,p'-DDD 6.40 × 10-1mg/kg,o,p'-DDD 1.00 × 10-2mg/kg,α-endosulfan 6.00 × 10-1mg/kg,β-endosulfan 2.10 × 10-1mg/kg, chlorpyrifos 3.00 mg/kg, and cypermethrin 4.00 × 10-2mg/kg. The most frequently detected compounds werep,p'-DDD and chlorpyrifos. The order of contamination was spinach > cabbage > onions. 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 above the maximum residue limits (MRLs) in 33.3-50% of the samples. The findings indicated risks and concerns for public health.
authors.affiliation: Chemistry Department, University of Dar es Salaam, P.O. Box 35061, Dar es Salaam, Tanzania.
authors.forename: John A M
authors.identifier: 0000-0002-0937-6253
authors.initials: JA
authors.lastname: Mahugija
authors.affiliation: Chief Government Chemist Laboratory Agency, Zanzibar, Tanzania.
authors.forename: Farhat A
authors.initials: FA
authors.lastname: Khamis
authors.affiliation: Chemistry Department, University of Dar es Salaam, P.O. Box 35061, Dar es Salaam, Tanzania.
authors.forename: Esther H J
authors.initials: EH
authors.lastname: Lugwisha