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 water

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

phototransformation in water

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP Guideline study

Study type:

direct photolysis

Qualifier:

according to guideline

Guideline:

EPA Guideline Subdivision N 161-2 (Photodegradation Studies in Water)

Qualifier:

according to guideline

Guideline:

other: EC-guidelines 94/37/EC and 95/36/EC

Qualifier:

according to guideline

Guideline:

other: Environmental Chemistry and Fate, Guidelines for Registration of Pesticides in Canada, PMRA, DACO No. 8.2.3.3.2, 1987

Principles of method if other than guideline:

This study was performed in compliance with the GLP standards followed by US EPA FIFRA 40 CFR Part 160, German Chemical Law Principles of Good Laboratory Practice, and Japan MAFF 11 Nousan Number 6283.

GLP compliance:

yes (incl. QA statement)

Radiolabelling:

yes

Analytical method:

high-performance liquid chromatography

other: TLC

Light source:

Xenon lamp

Light spectrum: wavelength in nm:

300 - 800

Relative light intensity:

569

Details on light source:

- Emission wavelength spectrum: 300-800 nm
- Filters used and their purpose: <290 nm cut-off UV-filter
- Relative light intensity based on intensity of sunlight: Relationship to natural sunlight 8.8 h/4.3 h suntest light is equivalent to 1 day unter extreme
conditions in June at Phoenix, AZ, USA and Athens, Greece, respectively
- Duration of light/darkness: Continuous exposure, 3 days

Details on test conditions:

TEST SYSTEM
- Type, material and volume of test apparatus/vessels: Static system; 50 mm x 26 mm x 16 mm quartz glass vessels fitted with traps.
- Sterilisation method: Autoclave
- Details of traps for volatile, if any: Static volatile trap attachment for CO2 (soda lime) and organic volatiles (polyurethane foam), permeable for oxygen.


TEST MEDIUM
- Volume used/treatment: 10 mL/treatment
- Preparation of test medium: Sterile aqueous 0.01 M phosphate buffer adjusted to pH 7
- Identity and concentration of co-solvent: Acetonitrile
- Concentration of solubilising agent: ≤ 0.2%

REPLICATION
- No. of replicates (dark): 2
- No. of replicates (irradiated): 2

Duration:

72 h

Temp.:

25 °C

Initial conc. measured:

1 mg/L

Reference substance:

yes

Dark controls:

yes

DT50:

1.3 - 1.4 d

Predicted environmental photolytic half-life:

The experimental DT50 of AE 1170437 for label A and label B were 1.3 and 1.4 days, respectively. The predicted environmental DT50 of AE 1170437 were 3.6 and 3.8 solar summer days for Phoenix, AZ, USA and 5.6 and 5.9 solar summer days for Athens, Greece, respectively. The experimental DT50 of the transformation compounds AE 1170437-olefine and AE 1170437-1-hydroxyethyl in the irradiated samples were > 42 days and 11 days, respectively.

Transformation products:

yes

No.:

#1

No.:

#2

Major Outcomes of the Study:

Based on the experimental DT50 of 1.3 and 1.4 days for AE 1170437 the predicted environmental DT50 is calculated to be 3.6 and 3.8 solar summer days at Phoenix, AZ, USA or 5.6 and 5.9 summer days at Athens, Greece for label A and label B, respectively. AE 1170437 was degraded in sterile aqueous 0.01 M phosphate buffer under photolytic conditions to the two main transformation products AE 1170437-olefine and AE 1170437-1-hydroxyethyl and to innumerable minor transformation products each < 5% of the AR. CO2 formation and organic volatile formation was negligible throughout the study (<1%).

From this study, it is evident that photodegradation of AE 1170437 in aqueous systems is a significant route for the elimination of this compound from the environment.

Reference 2

Endpoint:

phototransformation in water

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP Guideline study

Study type:

direct photolysis

Qualifier:

according to guideline

Guideline:

other: Phototransformation of Chemicals in Water, Part A: Direct Phototransformation, UBA, Berlin, Germany (1992); Test Method: ECETOC (Polychromatic Light Source)

GLP compliance:

yes (incl. QA statement)

Radiolabelling:

no

Analytical method:

high-performance liquid chromatography

Buffers:

- pH: acetate pH 4, phosphate pH 7, and borate pH 9
- Composition of buffer:

1) Acetate buffer solution pH 4
0.04 mol/L acetate buffer stock solution pH 4:
1.36 g CH3COONa ∗ 3 H2O was dissolved in a volume of 250 mL with water. The pH of
that solution was measured with a pH electrode and then adjusted at RT to pH 4.0 using
acetic acid.
0.01 M acetate buffer solution pH 4:
The buffer stock solution was diluted to the desired 0.01 mol/L with purified water (1/3,
v/v).

2) Phosphate buffer solution pH 7
0.04 mol/L phosphate buffer stock solution pH 7:
1.36 g KH2PO4 was dissolved in a volume of 100 mL with water, 74 ml of NaOH (0.04
mol/L) were added and the volume was adjusted to 250 mL with water. The pH of that
solution was measured with a pH electrode and then adjusted at 20°C to pH 7.0 using
NaOH (0.04 mol/L).
0.01 M phosphate buffer solution pH 7:
The buffer stock solution was diluted to the desired 0.01 mol/L with purified water (1/3,
v/v).

3) Borate buffer solution pH 9:
0.02 mol/L borate buffer stock solution pH 9:
0.62 g boric acid (H3BO3) and 0.75 g KCl were dissolved in 250 mL of water. A portion
of 53 mL of a 0.04 mol/L sodium hydroxide solution was added to 125 mL of the before
mentioned solution, mixed and then diluted with water to a final volume of 250 mL. The
pH of that solution was measured with a pH electrode and then adjusted at 20°C to pH
9.0 using NaOH (0.04 mol/L).
0.01 M borate buffer solution pH 9:
The buffer stock solution was diluted to the desired 0.01 mol/L with purified water (1/1,
v/v).

Light source:

other: artificial light

Light spectrum: wavelength in nm:

300 - 490

Duration:

300 min

Temp.:

25 °C

Reference substance:

no

Dark controls:

yes

Quantum yield (for direct photolysis):

0.479

DT50:

15 - 43 d

A degradation of AE1170437 in water of approximately 86 to 90% was measured by HPLC-UV during the maximum irradiation period of 300 minutes. In the corresponding dark sample no degradation was observed. This indicated that AE1170437 was not stable against direct phototransformation in aqueous solution. Using the UV absorption data and the degradation kinetics of both experiments a mean quantum yield of Φ = 0.4793 was calculated. The estimates based on Zepp & Cline and Frank & Kloepffer modelling were well comparable and considered the quantum yield and the absorption in a range of wavelengths relevant for the environment. Environmental half lives of about 15 to 43 days were assessed for the direct phototransformation of AE1170437 during the period of main use in spring to early summer. Thus, direct phototransformation in buffered water does contribute to the decomposition of AE1170437 in the environment. This assessment does not consider any indirect mechanisms, which may enhance the photodegradation in natural water.

With the arithmetic model developed by Zepp and Cline (1977) it is possible to transfer laboratory data concerning direct phototransformation in water to field conditions. Clouds are not considered, however. Therefore, the data obtained are to be viewed

more or less as minimal half-lives depending upon the frequency and degree of cloudiness. Using the quantum yield of Φ = 0.4793 and the molar extinction coefficients from 297.5 to 490 nm for calculation, "environmental half-lives" were obtained, e.g. for the mentioned marginal conditions.

Table 1: Computer Modelling according to Zepp and Cline (GC Solar)

Season	Environmental DT50of the Direct Phototransformation of AE1170437 [days]
	30thdegree lat.	40thdegree lat.	50thdegree lat.	60thdegree lat.
Spring	10.9	19.4	42.7	107
Summer	7.5	10	14.9	24.6
Fall	17.7	39.8	137	755
Winter	43.6	188	1520	15600

Table2 : Computer Modelling according to Frank and Kloepffer

Month	Photolysis Constant [1/sec]	Environmental DT50of the Direct Phototransformation of AE1170437 [days] Minimum Mean Maximum
January	0.168 x 10-8	2300	4800	22000
February	0.966 x 10-8	400	830	3600
March	0.500 x 10-7	84	160	670
April	0.169 x 10-6	26	47	190
May	0.316 x 10-6	16	25	100
June	0.455 x 10-6	12	18	71
July	0.457 x 10-6	12	18	58
August	0.401 x 10-6	13	20	67
September	0.163 x 10-6	29	49	180
October	0.471 x 10-7	90	170	770
November	0.522 x 10-8	670	1500	7700
December	0.805 x 10-9	4500	10000	50000

In contrast to the modelling according to Zepp and Cline, the arithmetic model developed by Frank and Kloepffer (1985) takes the conditions of cloudiness in Central Europe into consideration and is more geared to the conditions in Germany. Using the quantum yield of Φ = 0.4793 and the molar extinction coefficients from 292.5 nm to 490 nm for calculation environmental half-lives were obtained, e.g. for the mentioned marginal conditions.

Zepp R.G. and Cline D.M.: Environ. Sci. Technol. 11, 359 (1977)

Frank R. and Kloepffer W.: UBA Research Report No. 10602046 (1985)

Reference 3

Endpoint:

phototransformation in water

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP Guideline study

Study type:

direct photolysis

Qualifier:

according to guideline

Guideline:

EPA Guideline Subdivision N 161-2 (Photodegradation Studies in Water)

Qualifier:

according to guideline

Guideline:

other: Commission Directive 94/37/EC

Qualifier:

according to guideline

Guideline:

other: Commission Directive 95/36/EC

Qualifier:

according to guideline

Guideline:

other: Environmental Chemistry and Fate, Guidelines for Registration of Pesticides in Canada, PMRA, DACO No. 8.2.3.3.2, 1987

Principles of method if other than guideline:

This study was performed in compliance
with the GLP standards followed by US EPA FIFRA 40 CFR Part 160, German
Chemical Law Principles of Good Laboratory Practice, and Japan MAFF 11 Nousan
Number 6283.

GLP compliance:

yes (incl. QA statement)

Radiolabelling:

yes

Analytical method:

high-performance liquid chromatography

Details on sampling:

see table under materials and methods

Light source:

Xenon lamp

Light spectrum: wavelength in nm:

< 290

Relative light intensity:

300 - 800

Details on light source:

- Emission wavelength spectrum: 300-800 nm
- Filters used and their purpose: <290 nm cut-off UV-filter
- Light intensity at sample and area irradiated: 1044 W m-2
- Relative light intensity based on intensity of sunlight: 4.8 h suntest light is equivalent to 1 day under extreme conditions in June at Phoenix, AZ, USA and Athens, Greece, respectively.

Details on test conditions:

TEST SYSTEM
- Type, material and volume of test apparatus/vessels: Static system; 50 mm x 26 mm x 16 mm quartz glass vessels fitted with traps.
- Sterilisation method: Filter sterilization
- 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: yes, Range: 0.5 – 7.8%, mean: 2.2%

TEST MEDIUM
- Volume used/treatment: 10 mL/treatment
- Source of natural water: Rhine River Water
- Preparation of test medium: according to guideline
- Identity and concentration of co-solvent: Acetonitrile
- Concentration of solubilising agent: ≤ 0.1% of total volume

REPLICATION
- No. of replicates (dark): 2
- No. of replicates (irradiated): 2

Duration:

19.6 h

Temp.:

25 °C

Initial conc. measured:

1 mg/L

Reference substance:

yes

Dark controls:

yes

DT50:

5.7 h

Transformation products:

yes

No.:

#1

No.:

#2

Description of key information

Photodegradation of the test substance in aqueous systems is a significant route for the elimination of this compound from the environment.

Additional information

Three GLP guideline studies about photodegradation in artificial and natural water are available.

The aqueous phototransformation of the substance was studied at 25°C in sterile 0.01 M aqueous phosphate buffer solutions at pH 7 at an initial concentration of 1 mg/L by continuous exposure to a xenon lamp with <290 nm cut-off filter for three days. Based on the experimental DT50 of 1.3 and 1.4 days for the substance the predicted environmental DT50 is calculated to be 3.6 and 3.8 solar summer days at Phoenix, AZ, USA or 5.6 and 5.9 summer days at Athens, Greece for label A and label B, respectively. A second study investigated the phototransfomation at 25°C in sterile Rhine river water at a nominal concentration of 1 mg/L by continuous exposure to a xenon lamp with <290 nm cut-off filter for 19.6 hours, resulting in an experimental DT50 of 5.7 hours and the predicted environmental DT50 is calculated to be 2.5 environmental days at Tokyo, Japan or 1.2 environmental days at Phoenix, AZ, USA.

Thequantum yield of the direct phototransformation of the test substance was determined in water using polychromatic light according to the ECETOC method. A degradation of the substance in water of approximately 86 to 90% was measured by HPLC-UV during the maximum irradiation period of 300 minutes.

In the corresponding dark sample no degradation was observed. This indicated that the substance was not stable against direct phototransformation in aqueous solution. Using the UV absorption data and the degradation kinetics of both experiments a mean quantum yield ofΦ= 0.4793 was calculated.

It is evident that photodegradation of the substance in aqueous systems is a significant route for the elimination of this compound from the environment.