Prothioconazole/Trifloxystrobin

Ms. Karen Cain 6.
ENVIRONMENTAL FATE ASSESSMENT:
The following assessment was prepared by Engineering Geology staff within the Bureau
of Pest Management.
Technical Review of Trifloxystrobin
No environmental fate information was submitted for this active ingredient, so this review was
taken from the November 12, 1999 technical review of trifloxystrobin done for Flint and
Compass.
Solubility: Trifloxystrobin has a solubility of 0.61 ppm.
.
Hydrolysis: Trifloxystrobin was stable in pH 5, has a half-life of 55.2 days at pH 7, and
19.8 hours at pH 9.
Aqueous Photolysis: Trifloxystrobin had a half-life of 14.8 days; however EPA had
problems with this study.
Soil Photolysis: Degradation was too rapid to determine a half-life.
Aerobic Soil Metabolism: The half-life was biphasic with an apparent half-life of 0.72 days.
The registrant calculated half-life was 2.0-2.4 days. Degradate CGA 321113 was found at 85.2%
at 7 days in one study, at 93.2% at day 14 in a second study, and at 84.7% at 28 days and 39.5%
at one year in a third study. CGA-357276 was found at 4.9% at 270 days, CGA-373466 and
CGA-357262 were each found at < 4.1% from days 90 to 365 in the second study. CGA-
373466, CGA-357261, CGA-331409 and CGA-320299 were each found at 1% throughout the
third study.
Aerobic Aquatic Metabolism: EPA was not satisfied with this study, but did state that the
study indicated that trifloxystrobin degraded rapidly in aquatic aerobic environments.
Anaerobic Aquatic Metabolism: The half-life was 0.72 days
Aged Leaching: EPA did not accept this study, but did indicate that degradate CGA-321113 was
very mobile in loamy sand, sandy loam and silt loam as well as mobile in loam and clay loam.
CGA-356276 was present in quantities too low to assess mobility.
Adsorption-Desorption Parent:
Soil Type Adsorption Koc Desorption Koc
Loamy sand 2354 3294
Sandy loam 951 1387
Low OM sand 3064 3528
High OM sand 3927 2202
Clay loam 9871 2504
Silt loam 951 1203