1,3,5-Triazine-2,4-diamine, N2-[(1R,2S)-2,3-dihydro-2,6-dimethyl-1H-inden-1-yl]-6-(1-fluoroethyl)-

Phototransformation in soil

Link to relevant study record(s)

Reference

Endpoint:

phototransformation in soil

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EPA Guideline Subdivision N 161-3 (Photodegradation Studies on Soil)

Qualifier:

according to guideline

Guideline:

other: Commission Directive 95/36/EC amending Council Directive 91/414/EEC concerning the placing of plant protection products on the market, Official Journal of the European Communities No. L172, July 14, 1995

Qualifier:

according to guideline

Guideline:

OECD Guideline draft (Phototransformation of Chemicals on Soil Surfaces)

Version / remarks:

(Drafts 2002 and 2004)

GLP compliance:

yes (incl. QA statement)

Radiolabelling:

yes

Analytical monitoring:

yes

Analytical method:

high-performance liquid chromatography

Details on soil:

COLLECTION AND STORAGE
- Geographic location: The soil used in this study (ID: Pikeville) was collected from the Pikeville, North
Carolina, USA.


PROPERTIES
- Soil classification system and year: It was characterized as loamy sand according to the USDA criteria
- Soil texture
- % sand: 80
- % silt: 14
- % clay: 6
- Organic carbon (%): 0.7 %
- CEC (meq/100 g): 4.8 meq/100 g soil dry wt
- Field moisture capacity at 15 bar: 2.2 g water/100g soil dry wt
- Bulk density (g/cm3): 1.51 g/cm3
- Initial microbial biomass/microbial population (unit):
- Final microbial biomass/microbial population (unit):

Light source:

Xenon lamp

Light spectrum: wavelength in nm:

< 290

Relative light intensity:

300 - 800

Details on light source:

- Emission wavelength spectrum: 300-3000 nm
- Filters used and their purpose: <290 nm cut-off UV-filter
- Light intensity at sample and area irradiated: 697 W x m-2 (300 – 800 nm) for label 1 and 728 W x m-2 (300 – 800 nm) for label 2
- Relative light intensity based on intensity of sunlight:
Label 1:
7.98 hours exposure in Suntest is equivalent to 1 day under
extreme conditions in June at Phoenix, Arizona
10.125 days exposure in Suntest is equivalent to 30.5 days under
extreme conditions in June at Phoenix, Arizona
Label 2:
6.85 hours exposure in Suntest is equivalent to 1 day under
extreme conditions in June at Phoenix, Arizona
8.875 days exposure in Suntest is equivalent to 31.1 days under
extreme conditions in June at Phoenix, Arizona

Details on test conditions:

TEST SYSTEM
- Type, material and volume of test apparatus or thin layers: Static system; 4-cm diameter quartz glass vessels fitted with traps
- Volume of test solution used/treatment: 50 μL acetonitrile with test item
- Method of application: Small droplets were applied onto the soil surface homogeneously distribute by a gastight glass syringe (Unimetrix)
- Co-solvent evaporated: Yes, 15 min without trap attachment
- Details of traps for volatile, if any: Static volatile trap attachment for CO2 (soda lime) and organic volatiles (polyurethane foam), permeable for oxygen.
- Indication of test material adsorbing to the walls of test apparatus: no


REPLICATION
- No. of replicates (dark): Duplicate each label
- No. of replicates (irradiated): Duplicate each label

MAINTENANCE OF TEST CONDITIONS SPECIFIED UNDER "DURATION"
- Temperature maintenance method: Cryostat-controlled. The temperature was measured in a separate test vessel filled with the same portion of soil and continuously registered.
- Moisture maintenance method: N/A, moisture was maintained throughout the study

Duration:

10 d

Temp.:

20 °C

Initial conc. measured:

17.27 other: μg / 10.2 cm² soil surface

Duration:

9 d

Temp.:

20 °C

Initial conc. measured:

16.83 other: μg / 10.2 cm² soil surface

Reference substance:

yes

Dark controls:

yes

DT50:

28.3 - 42.8 d

Test condition:

calculated for natural conditions, extreme light intensity in midsummer in Phoenix, (AZ, US).

DT50:

43.8 - 66.3 d

Test condition:

calculated for natural conditions, in moderate conditions like Athens (Greece, EU)

DT50:

9.4 - 12.2 d

Test condition:

experimental in the irradiated samples

DT50:

98 - 183 d

Test condition:

experimental in the dark controls

Transformation products:

yes

The DT50 in the main test was calculated for natural conditions, e.g. extreme light intensity in midsummer in Phoenix, (AZ, US). The DT50 is 28.3 and 42.8 days (mean 35.6 days) under exposure to sunlight. Under moderate conditions like e.g. Athens (Greece, EU) the DT50 is 43.8 and 66.3 days (mean 55.1 days) Therefore it is evident, that photodegradation of AE 1170437 on soil surfaces is not a significant route for the elimination of this compound from the environment, especially under naturally occurring and more relevant irradiation conditions.No metabolite is formed in significant amounts due to photolysis, only.

Comparing both systems, the transformation pathway is in general the same in dark and in irradiated test systems. The first and major transformation step under both conditions is the oxidation of the indanyl moiety forming AE 1170437 – triazine indanone and cleavage of the indanyl moiety forming AE 1170437 - diaminotriazine. In addition, bound residues were generated due to irradiation. The degradation pattern is comparable to the metabolic pathway in the aerobic soil metabolism studies. No additional metabolite was formed due to photolysis in significant amounts. A supplementary test with dried soil and a second soil type showed, that these variations did not influence the behavior. The result was in line with the main test. No additional metabolite was formed significantly with exposure to light under varied conditions. The overall behavior of AE 1170437 under exposure to light is in line with the low UVabsorption of the test item beyond 290 nm.

Result Synopsis:

	[triazine-2,4-14C] AE 1170437Label 1 Irradiated                Dark		[indane-3-13/14C] AE 1170437Label 2 Irradiated                 Dark
Suntest ID / intensity (300 – 800 nm)	5 / 625 W*m-2	-	2 / 728 W*m-2	-
DT50[days]*experimental	9.4	98.0	12.2	183
DT50Phototransformation products [days]	Not determined	Not determined	Not determined	Not determined
Transformation products (>2% AR)	AE1170437-triazine indanone (Z1)		AE1170437-triazine indanone (Z1)
	AE1170437-diaminotriazine (Z2)
Minor transformation products (<2% AR)	AE1170437-carboxylic acid (Z8)	AE1170437-triazine indanone (Z1)	AE1170437-carboxylic acid (Z8)	AE1170437-triazine indanone (Z1)
		AE1170437-diaminotriazine (Z2)
	6 unknown metabolites		4 unknown metabolites

Description of key information

Photodegradation in soil is not seen as an important process in the fate of the test substance.

Additional information

The phototransformation of radiolabeled test substance was studied on a loamy sand soil (pH 5.6, organic carbon 0.7%) from USA, North-Carolina, Pikeville equivalent to a projected application rate of 150 g/ha for ten and nine days.

The experimental DT50 values are ranged from 9.4 to 12.2 days and based on 7.98 and 6.85 experimental hours representing 1 solar day at; the mean experimental half life is equivalent to 35.6 solar days under extraordinary light intensity at, e. g. Phoenix, US. The equivalent mean DT50 data for moderate intensity at e. g. Athens (EU) is 55.1 days. From this study, it is evident that photo-degradation of the test substance on soil surfaces is not a significant route for the elimination of this compound from the environment. No metabolite is formed in significant amounts due to photolysis, only.