Determination of Organochlorine and Synthetic Pyrethroid Pesticide Residues in Water Samples Collected from Different Locations of Bangladesh

The present study was aimed to validate an analytical method for the quantification of 19 organochlorine and 2 synthetic pyrethroid pesticide residues in water samples using modified quick, easy, cheap, effective, rugged and safe (QuEChERS) extraction and Gas Chromatography coupled with Electron Capture Detector (ECD). The selected pesticide residues were determined by in-house validated method. The analytical method was validated by evaluating the accuracy, precision, linearity, limit of detection (LOD) and limit of quantification (LOQ). The average recoveries of the selected pesticides ranged from 78% to 117% with RSDr ≤ 12% in two fortification levels of 0.02 and 0.1 mg/L. The linearity was ≥0.995 for all of the selected pesticides. The LOD ranged from 0.003 to 0.006 mg/L and the LOQ was 0.02 mg/L for all the selected analytes. This method was applied satisfactorily for the residue analysis of 108 water samples collected from nine districts of Bangladesh. Among the analyzed samples, only 4 had cypermethrin residues (0.026 mg/L, 0.034 mg/L, 0.045 mg/L and 0.05 mg/L). The level of detected cypermethrin residues were above the WHO recommended guide line values of water quality.