Fate and behaviour of flupyrsulfuron-methyl in soil and aquatic systems

The environmental fate of [14C]flupyrsulfuron‐methyl, a sulfonylurea herbicide, was investigated in soil and aquatic systems. The major degradative pathways in both systems were contraction of the sulfonylurea bridge followed by intramolecular rearrangement (at pH>7) or sulfonylurea bridge hydrol...

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Bibliographic Details
Published in:	Pesticide Science Vol. 55; no. 3; pp. 288 - 300
Main Authors:	Singles, Suzanne Koch, Dean, Gary M, Kirkpatrick, David M, Mayo, Bruce C, Langford-Pollard, Anne D, Barefoot, Aldos C, Bramble Jr, Frederick Q
Format:	Journal Article Conference Proceeding
Language:	English
Published:	London John Wiley & Sons, Ltd 01-03-1999 Wiley London :John Wiley & Sons Ltd
Subjects:	adsorption Agronomy. Soil science and plant productions Biological and medical sciences degradation dissipation environmental fate flupyrsulfuron-methyl Fundamental and applied biological sciences. Psychology hydrolysis Soil and water pollution Soil science sulfonylurea sulfonylurea herbicides Anaerobiosis Biodegradation Microbial activity Aerobiosis Radiolabelling Pollutant behavior Pesticides Property of soil Soil pollution Sediments Texture Herbicide Sorption Hydrolysis Adsorption Photolysis Environment impact Sulfonylureas Molecular rearrangement pH Water pollution Degradation product Half life Chemical weed control
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Summary:	The environmental fate of [14C]flupyrsulfuron‐methyl, a sulfonylurea herbicide, was investigated in soil and aquatic systems. The major degradative pathways in both systems were contraction of the sulfonylurea bridge followed by intramolecular rearrangement (at pH>7) or sulfonylurea bridge hydrolysis (at pH<7). Hydrolysis was a first‐order reaction and was pH‐ and temperature‐dependent. Flupyrsulfuron‐methyl was degraded rapidly at 25°C in pH 5, 7 and 9 sterile buffers with half‐lives of 44, 12 and 0.42 days, respectively. At pH 7 and 9, sulfonyl bridge contraction and rearrangement was the major degradative mechanism; at pH 5 the sulfonylurea bridge was also hydrolysed. Unique photodegradation products were formed at pH 5 and pH 7 but, in general, hydrolysis was faster than photolysis at all three pH values. Aerobic aquatic metabolism involved biphasic degradation of the herbicide (DT50 3–6 days), degradation being faster in the aerobic aquatic systems than in sterile buffers. Degradation in aerobic soils was rapid, both in the laboratory (DT50 8–26 days) and in the field (DT50 6–11 days, DT90 35–123 days). In laboratory studies the rate of degradation in soil reduced with decreasing temperature (rate at 10°C half that at 20°C) but was unaffected by soil water content (50% vs 70% maximum water holding capacity). The compound was degraded in flooded anaerobic soils (DT50 33 days). Flupyrsulfuron‐methyl was weakly absorbed to soils, there being a linear relationship between adsorption and soil organic carbon content. Following application of [14C]flupyrsulfuron‐methyl to bare field soil the radioactivity moved little, with very little radioactivity found in soil below 60 cm from the surface. © 1999 Society of Chemical Industry
Bibliography:	Based on poster presentations at the 9th International Congress of Pesticide Chemistry, organised by the International Union of Pure and Applied Chemistry (IUPAC), and held in London, UK, 2-7 August 1998. istex:7C828414540FCE888124CE7243BF9FA3F8B7A87D ArticleID:PS890 ark:/67375/WNG-SZSH1Q3M-J Based on poster presentations at the 9th International Congress of Pesticide Chemistry, organised by the International Union of Pure and Applied Chemistry (IUPAC), and held in London, UK, 2–7 August 1998. ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Conference-1 ObjectType-Feature-3 content type line 23 SourceType-Conference Papers & Proceedings-2
ISSN:	0031-613X 1526-498X 1096-9063
DOI:	10.1002/(SICI)1096-9063(199903)55:3<288::AID-PS890>3.0.CO;2-6