The mobility of diazinon (O,O-diethyl-O-2-isopropyl-6-methylpyrimidin-
4-yl phosphorothioate) in soil columns modified with three organic ame
ndments and with hexadecyltrimethylammonium bromide was studied. Based
on the percolation curves and residual pesticide partitioning in the
columns, all four amendments reduced leaching of the pesticide from so
il. The effect was found to be related to the nature and carbon conten
t of the amendments, the presence of soluble fractions in them and the
soil texture.