Methiozolin is new herbicide. It controls annual blueglass (poa annua) in various cool-and warm-season turfgrasses. The objective of this study was to investigate the fate of the, Methiozolin, under anaerobic conditions. According to the OECD and EPA registration guidelines for anaerobic fate, flow-through system was prepared and Methiozolin treated soil samples were incubated for 21 days in the dark under aerobic condition. At 21 days after treatment (DAT) the aerobic soil samples were flooded and the flow-through system flushed with nitrogen instead of air in order to establish and maintain anaerobic condition. Extracts from water and soil, ethylene glycol for volatile, 2N sodium hydroxide for 14CO2 and bound (unextractable) 14C-residues were quantified using liquid scintillation counter (LSC) and sample oxidizer, and furthermore characterized. During the aerobic condition (0 ~ 21 DAT), Methiozolin rapidly decreased from 96.9% of applied radioactivity (AR) at 0 DAT to 46.5% AR at 21 DAT. After changing from aerobic to anaerobic condition, the degradation of Methiozolin was reduced substantially. No major metabolite (=10% of applied 14C) was observed in both of soil condition, whereas at least ten minor metabolites were observed at the water and soil phase. Mineralization occurred with 14CO2 amount reaching 11.6% AR after 21 days of aerobic incubation. During the anaerobic incubation, no significant mineralization occurred. No other volatile compounds were detected throughout the incubation. And the time observed for half-life calculated by pseudo-first-order kinetics was more than 120 days in anaerobic condition. More than 30% of the applied 14C was incorporated into sediment-bound residue.

Anaerobic soil metabolism of Methiozolin

248th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.