Abiotic degradation (photodegradation and hydrolysis) of imidazolinone herbicides

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dc.contributor.authorRamezani, M.
dc.contributor.authorOliver, D.
dc.contributor.authorKookana, R.
dc.contributor.authorGill, G.
dc.contributor.authorPreston, C.
dc.date.issued2008
dc.description.abstractThe abiotic degradation of the imidazolinone herbicides imazapyr, imazethapyr and imazaquin was investigated under controlled conditions. Hydrolysis, where it occurred, and photodegradation both followed first-order kinetics for all herbicides. There was no hydrolysis of any of the herbicides in buffer solutions at pH 3 or pH 7; however, slow hydrolysis occurred at pH 9. Estimated half-lives for the three herbicides in solution in the dark were 6.5, 9.2 and 9.6 months for imazaquin, imazethapyr and imazapyr, respectively. Degradation of the herbicides in the light was considerably more rapid than in the dark with half lives for the three herbicides of 1.8, 9.8 and 9.1 days for imazaquin, imazethapyr and imazapyr, respectively. The presence of humic acids in the solution reduced the rate of photodegradation for all three herbicides, with higher concentrations of humic acids generally having greater effect. Photodegradation of imazethapyr was the least sensitive to humic acids. The enantioselectivity of photodegradation was investigated using imazaquin, with photodegradation occurring at the same rate for both enantiomers. Abiotic degradation of imidazolinone herbicides on the soil surface only occurred in the presence of light. The rate of degradation for all herbicides was slower than in solution, with half-lives of 15.3, 24.6 and 30.9 days for imazaquin, imazethapyr and imazapyr, respectively. Abiotic degradation of these herbicides is likely to be slow in the environment and is only likely to occur in clear water or on the soil surface.
dc.description.statementofresponsibilityMohammadkazem Ramezani, Danielle P. Oliver, Rai S. Kookana, Gurjeet Gill, Christopher Preston
dc.identifier.citationJournal of Environmental Science and Health Part B: Pesticides, Food Contaminants, and Agricultural Wastes, 2008; 43(2):105-112
dc.identifier.doi10.1080/03601230701794968
dc.identifier.issn0360-1234
dc.identifier.issn1532-4109
dc.identifier.orcidKookana, R. [0000-0002-0477-3284]
dc.identifier.orcidGill, G. [0000-0002-3773-8100]
dc.identifier.orcidPreston, C. [0000-0002-7588-124X]
dc.identifier.urihttp://hdl.handle.net/2440/52257
dc.language.isoen
dc.publisherMarcel Dekker Inc
dc.source.urihttps://doi.org/10.1080/03601230701794968
dc.subjectHumic Substances
dc.subjectNicotinic Acids
dc.subjectNiacin
dc.subjectImidazoles
dc.subjectQuinolines
dc.subjectHerbicides
dc.subjectSoil Pollutants
dc.subjectChromatography, High Pressure Liquid
dc.subjectEnvironmental Pollution
dc.subjectHydrolysis
dc.subjectDose-Response Relationship, Drug
dc.subjectKinetics
dc.subjectAdsorption
dc.subjectHydrogen-Ion Concentration
dc.subjectPhotochemistry
dc.subjectHalf-Life
dc.titleAbiotic degradation (photodegradation and hydrolysis) of imidazolinone herbicides
dc.typeJournal article
pubs.publication-statusPublished

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