Levels and Potential Health Hazards of Chlorinated Pesticides in Surface Water Samples of Charsadda Area of Pakistan Using SPME-GC-ECD Technique

In the present study, we determined the levels of chlorinated pesticide residues in surface water samples collected from the Charsadda district (KPK, Pakistan). SPME-GC-ECD with COMBI PAL CTC autosampler was used for extraction and analysis of 20 organochlorine pesticides in the collected water samples. For maximum efficiency of the SPME procedure, several parameters were studied, including the extraction and desorption time of the fiber, solution pH, agitation of samples, and stirring speed, etc. This method showed good liner response, with R-2 values in the range of 0.9887 to 0.9999 for all pesticides. This method also provided good percent recoveries at 1 mu g L-1 (87.5 to 106.0%) and at 2 mu g L-1 (88.5 to 109.2%). Lower limits of detection for all 20 chlorinated pesticides were found to be lower than their maximum permissible contamination levels. Approximately 50% of the surface water samples collected from the Charsadda district were found to be contaminated with the pesticides gamma-BHC, heptachlor, aldrin and dieldrin, with maximum concentrations of 0.023, 0.108, 0.014 and 0.013 mu g L-1, respectively. For adults and children, the cancer risk from water due to contamination by various pesticides ranged from 0 to 33.29 x 10(-6). The non-carcinogenic risk from each pollutant in the water samples of the Charsadda district was found to be in the order of heptachlor > aldrin > dieldrin > gamma-BHC. However, the pesticides alpha-BHC, beta-BHC, heptachlor epoxide, chlordane, endrin, 4,4 '-DDD, endrin ketone, 4,4 '-DDT, endosulfan sulfate and methoxychlor were not detected in any of the surface water samples of investigated in the present study.