Determination of Pesticide Residues of Organochlorine in Some Local and Imported Foods in Qatar

Abstract

The study was aimed to examine the residues of pesticide in vegetables and fruits in Qatar. The total numbers of samples that were collected were 127 samples of seven most consumed fresh vegetables and fruits from local and import production. The samples were then extracted using Acceleration Solvent Extractor (ASE) and cleaned up using two solid phase extraction (SPE): florisil and silica gel. Gas chromatography with an electron capture detector (GC/ECD) was used to analyze the ten organochlorine pesticides (OCPs). In addition, scan mode of gas chromatography with mass spectrometry (GC/MS) was used in to screen the pesticides residues in these vegetables and fruits. Ninety percent of the imported samples recorded residues above the MRL with at least one of the selected OCPs and about 30% of the local samples (mostly leafy vegetables) contained residues above the MRL. The most frequently detected OCPs in the samples were heptachlor (found in 75 samples) and was detected mostly in imported samples, g-chlordane (found in 22 samples) and a-chlordane (found in 19 samples). Two statistical analysis tests were used to determine significance (pair-difference t-test and analysis of variance (ANOVA)). In most of the comparisons between the washed and unwashed samples, no-significant differences were observed (P > 0.05). Though, it seems that the effects of washing the samples with tap water differ in organochlorine residues based on the type of vegetables and fruits. The interaction between the washing treatment and countries for heptachlor on parsley showed significant difference. Accordingly, there is a dire require for controlling program for residues of pesticides in food products, especially in imported food products.