Influence of metal salts on the photodegradation of imazapyr, an imidazolinone pesticide.
The behaviour of imazapyr (2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)nicotinic acid), a broad spectrum herbicide of the imidazolinone family, has been studied under UV radiation in the presence of metal salts. Complexation interactions between imazapyr and metal ions decreased imazapyr photolysis. A chemometric study compared the photodegradation of imazapyr in aqueous solutions in the presence of Na+, Ca2+ or Cu2+ and their concomitant anionic species (Cl-, NO3-) at various pesticide/metal ion molar ratios. The study showed the major role of metal ions in the degradation of imazapyr and its main photoproducts. The molecules were strongly stabilised on complexation with metal ions, leading to an increase in persistence of the pesticide.
Laboratoire des Sciences Analytiques, UMR 5180, Université Claude Bernard Lyon 1, Bâtiment Raulin, 43 Boulevard du 11 Novembre 1918, F-69622 Villeurbanne Cedex, France.
Etienne
E
Quivet
René
R
Faure
Joseph
J
Georges
Jean-Olivier
JO
Paissé
Pierre
P
Lantéri
D003300:Copper; D006540:Herbicides / Q000528:radiation effects*; D007093:Imidazoles / Q000378:metabolism / Q000528:radiation effects*; D009525:Niacin / Q000031:analogs & derivatives* / Q000378:metabolism / Q000528:radiation effects; D010573:Pesticide Residues / Q000528:radiation effects*; D012492:Salts; D014466:Ultraviolet Rays; D014874:Water Pollutants, Chemical / Q000528:radiation effects
D006540:Herbicides; D007093:Imidazoles; D010573:Pesticide Residues; D012492:Salts; D014874:Water Pollutants, Chemical; D009525:Niacin; C076656:imazapyr; D003300:Copper