Abstract:

Watermelon (Citrulus lanatus) samples were randomly collected from seven major markets in Birnin-Kebbi and environs. The samples were divided into three groups: unwashed, detergent-washed and washed with tap water. Samples were extracted with cyclohexane and ethylacetate (1:1) and the chlorpyrifos residues in the sample extracts were determined with GC-MS Perkin-Elmer model fitted with Electron Capture Detector (ECD 63Ni) and Nitrogen Phosphorus Detector (NPD). Results showed that 100% of the samples analysed contained chlorpyrifos pesticide residue. The unwashed watermelon fruits, detergent-washed and tap water washed have mean concentrations of 0.114±0.006µg/g, 0.006±0.002µg/g and 0.009±0.003µg/g respectively. The chlorpyrifos residue levels obtained in this work exceeded the Maximum Residue Limit (MRL) established by FAO/WHO indicating a possible contamination of the fruits. Statistical analysis with one-way ANOVA (SPSS 20.0) showed that there is a decrease in the levels of chlorpyrifos pesticide residues significantly between the unwashed watermelon fruits and the detergent-washed, while there seem to be no difference statistically in residues levels between the detergent-washed fruits and the water-washed watermelon fruits (P ≤0.05).