Bispyribac sodium underwent a moderate degradation when exposed to sunlight. The half-life for [14C]
bispyribac sodium ranged from 32.04 days for the irradiated samples to 41.82 days for the dark control
samples treated at 2 ppm. In addition to the parent compound, up to 12 other degradates were detected at
various time points in both the irradiated and dark control samples. The degradates observed were very
similar between both the irradiated and dark control samples suggesting that aerobic soil metabolism
processes predominated over soil photolysis processes. The identified degradates were Me2BA, Na-BX-180,
DesMe 2023, MeBA, DesMe 180 and 14CO2, as identified in the laboratory fate studies.