title: Metabolism of Pyrithiobac Sodium in Soils and Sediment, Addressing Bound Residues via Kinetics Modeling.
abstract: Degradation of pyrithiobac sodium (PE350) was examined in a number of soils and sediments using (14)C-PE350. It degrades primarily via microbial degradation which leads to the separation of the two rings of the molecule. Identification of several metabolites, many of which were minor products, helped to understand the formation of nonextractable residues (NER) and (14)CO2. In all studies, unextractable residues accounted for a large portion (20-60%) of the residues. Traditional kinetics modeling treats NER and CO2 as a single compartment, stated as sink, and formation mechanism of such components individually is ignored. Since studies conducted with radiolabeled test substance provides an accurate measurement of NER and CO2, we have demonstrated that kinetics modeling with these compartments separately can be used to clarify degradation pathways, including the origin of NER and CO2. This work demonstrated that overall metabolism in soils and sediments proceeded via similar pathways, and kinetics modeling was useful in clarifying the degradation route and formation of NER in all studies.
authors.affiliation: Stine Haskell Research Center, E.I. DuPont de Nemours and Co , 1090 Elkton Road,Newark, Delaware 19714, United States.
authors.forename: Ashok K
authors.initials: AK
authors.lastname: Sharma
authors.affiliation: ABC Laboratories, Inc. , 4780 Discovery Drive, Columbia, Missouri 65201, United States.
authors.forename: Lian
authors.initials: L
authors.lastname: Wen
authors.affiliation: ABC Laboratories, Inc. , 4780 Discovery Drive, Columbia, Missouri 65201, United States.
authors.forename: Larry R
authors.initials: LR
authors.lastname: Hall
authors.affiliation: ABC Laboratories, Inc. , 4780 Discovery Drive, Columbia, Missouri 65201, United States.
authors.forename: John G
authors.initials: JG
authors.lastname: Allan
authors.affiliation: ABC Laboratories, Inc. , 4780 Discovery Drive, Columbia, Missouri 65201, United States.
authors.forename: Brett J
authors.initials: BJ
authors.lastname: Clark
mesh_terms: D001565:Benzoates / Q000737:chemistry*; D019015:Geologic Sediments / Q000737:chemistry*; D006540:Herbicides / Q000737:chemistry*; D007700:Kinetics; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000737:chemistry*
chemical_list: D001565:Benzoates; D006540:Herbicides; D012987:Soil; D012989:Soil Pollutants; C401888:pyrithiobac sodium
keywords: NER; aquatic degradation; bound residues; kinetics modeling; nonextractable residues; pyrithiobac sodium; sediment degradation; soil metabolism