Products and Kinetics of Cloransulam-methyl Aerobic Soil Metabolism

Cloransulam-methyl aerobic soil metabolism was investigated to ascertain rates and products of environmental dissipation. Cecil loamy sand and Hanford loam fortified with 66 ng of [14C]cloransulam-methyl g-1 of soil were incubated in the dark at 25 °C and 100 kPa of moisture potential under positive...

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Bibliographic Details
Published in:	Journal of agricultural and food chemistry Vol. 44; no. 1; pp. 324 - 332
Main Authors:	Wolt, Jeffrey D, Smith, Joelene K, Sims, Jerry K, Duebelbeis, Dennis O
Format:	Journal Article
Language:	English
Published:	Washington, DC American Chemical Society 01-01-1996
Subjects:	Animal, plant and microbial ecology Applied ecology Biological and medical sciences Chemical control DEGRADACION DEGRADATION Ecotoxicology, biological effects of pollution EXTRACCION EXTRACTION Fundamental and applied biological sciences. Psychology HALF LIFE METABOLISM METABOLISME METABOLISMO Parasitic plants. Weeds PERSISTENCE Phytopathology. Animal pests. Plant and forest protection SOIL SOL SUELO SULFAMIDE SULFONAMIDAS SULPHONAMIDES Terrestrial environment, soil, air Weeds United States North America America Terrestrial environment Biodegradation Agricultural chemical product Sulfonamide Aerobiosis Pesticides Pesticide fate Radioactive tracers Sorptivity Metabolism Herbicide Entisols Soils Residue Triazole derivatives Loam soil Environment Pyrimidine derivatives Ultisols Kinetics Degradation product Loamy sand soil Labelled compound
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Summary:	Cloransulam-methyl aerobic soil metabolism was investigated to ascertain rates and products of environmental dissipation. Cecil loamy sand and Hanford loam fortified with 66 ng of [14C]cloransulam-methyl g-1 of soil were incubated in the dark at 25 °C and 100 kPa of moisture potential under positive O2 pressure for up to 357 days. Cloransulam-methyl exhibited a biphasic pattern of degradation. Aerobic soil half-lives were 9 and 13 days, respectively, on Cecil and Hanford soils for data fit to a two-compartment model and 16 and 21 days, respectively, for data fit to a first-order initial rate model. Degradation rates decreased ≈10-fold when soils were incubated at 5 °C or when sterilized by γ-irradiation. Evolved 14CO2 accounted for up to 10% of applied 14C. Metabolites (cloransulam, 5-hydroxycloransulam-methyl, and 5-hydroxycloransulam) occurred in acetone/acetic acid extracts at maximum concentrations of 25, 9, and 8 ng g-1, respectively, and were significantly less phytotoxic than the parent molecule. Bound residues accumulated up to 76% of applied 14C. Degradation rate and sorptivity were further investigated on 16 soils fortified with 189 ng g-1 of [14C]cloransulam-methyl and incubated for up to 55 days. Apparent first-order half-lives ranged from 13 to 28 days (mean ± SE = 18 ± 4 days). Apparent K d values, produced using a two-step extraction, ranged from 0.19 to 4.89 L kg-1 for cloransulam-methyl. Cloransulam-methyl metabolites, when present, tended to exhibit lower K d values than the parent molecule. Apparent K d increased with time. Keywords: DE-565; triazolopyrimidine sulfonanalide; soil degradation
Bibliography:	T01 P33 1997053905 ark:/67375/TPS-DKLS5SBP-2 Abstract published in Advance ACS Abstracts, December 1, 1995. istex:BE0A9091703C3FEAEB35A7F5F002B0BFBB210136
ISSN:	0021-8561 1520-5118
DOI:	10.1021/jf9503570