Submitted to: Symposium on the Fate and Chemistry of Modern Pesticides Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 8/21/2001
Publication Date: N/A
Technical Abstract: The sorption capacity and possible mechanisms of sorption of two new sulfonylaminocarbonyltriazolinone herbicides, methyl 2-[[[(4,5-dihydro-4- methyl-5-oxo-3-propoxy-1H-1,2,4-triazol-1-yl) carbonyl] amino] sulfonyl] benzoate (MKH 6561) and (4, 5 dihydro - 3 methoxy - 4 methyl - 5 - oxo- N- [ [2-(trifluoromethyoxy) phenyl] sulfonyl]- 1 H- 1, 2, 4- triazole-1-c) (MKH 6562), and their respective metabolites, 2,4-dihydro-4-methyl-5- propoxy-3H-1,2,4-triazol-3-one (6561M) and (2- trifluoromethoxybenzenesulfonamide (6562M) on octadecyl (C18) and dioctadecyldimethylammonium (DOD) saturated and Fe and Na saturated smectites has been investigated. Sorption of MKH 6561 on inorganic clays and C18 organoclays was much higher than for MKH 6562, but was similar on DOD saturated clays. For C18 saturated clays, sorption of both parent compounds increased with decreasing layer charge of the smectite. Sorption of 6561M, which was much lower than for its parent compound MKH 6561, was higher on inorganic and C18 saturated clays than on DOD saturated clays. 6562M metabolite sorption, which was also lower than the corresponding parent compound MKH 6562, was higher on DOD saturated clays than on C18 or inorganic saturated clays. Results indicate that the sorption space between the exchangeable organocation (greater in low charge smectite and primary alkylcation saturation) is as relevant as hydrophobicity and basal spacing of the organoclay (greater in high layer charge smectite and quaternary alkylcation saturation), and confirm that partition mechanism is not the only mechanism of sorption of this class of herbicides or other polar organic compounds on organoclays.