in order to study the residues of phosphorous insecticides in mazandaran district of iran, ethion, azinphosmethyl, diazinon and malathion four most used pesticides were chosen and river water samples were collected in april to sept. 2000, throughout the mazandaran state. thin layer chromatography was used, since it was the best applicable method in area with reasonably high level of sensitivity...

viAcknowledgments, vAppendices, 51AppendixTable of Minimum Weights, 52Bibliography, 56Dedication, iv