ABSTRACT
The growing population and increasing needs to agricultural products increased use of pesticides resulting in contamination of the environment, including water. The purpose of this study was to determinationof pesticide residuesin agricultural water resources in Barzok city of Kashan in 2011. This study as a descriptive and cross-sectional study that was conducted at spring season. That totals of 135 samples of the agricultural water resources of Barzok were collectedrandomly and mixtures from different stations. After extraction and preparation of samples, the pesticide residueswere determined by using the HPTLC [High Performance Thin Layer Chromatography] devices and CATS4 software. Finally, obtained data were analyzed by using ANOVA statistical methods. The results of this study showed that maximum amount of diazinon and chlorpyrifos has been 22.43 and 11.79 ppm respectively, and thepesticide residueshave declined gradually overtime of [p<0.001].Furthermore, after a month 95.9% of Chlorpyrifos and 88.8% of diazinon is degraded. Accordingly, the remaining of diazinon and chlorpyrifos after a month of spraying was higher than determined limited standards. Because Chlorpyrifos is broken down rapidly more than diazinon, it is recommended that besides educating farmers on the proper use of pesticides, unnecessary contact with the water resources of this region must stop at least one month after spraying.