1-[[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]methyl]-1H-1,2,4-triazole

Phototransformation in soil

Link to relevant study record(s)

Reference

Endpoint:

phototransformation in soil

Type of information:

experimental study

Adequacy of study:

key study

Study period:

12 Jun 2012 to 06 Sep 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline draft (Phototransformation of Chemicals on Soil Surfaces)

Version / remarks:

January 2002

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: EPA Guideline OPPTS 835.2410 (Photodegradation in Soil)

Version / remarks:

October 2008

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: ECC Directive 95/36/EC (Supplementary Studies/Soil Photolysis)

Version / remarks:

14 July 1995

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Radiolabelling:

yes

Analytical monitoring:

yes

Analytical method:

high-performance liquid chromatography

other:

Details on sampling:

See Table 1 in 'Any other information on materials and methods incl. tables'.

Details on soil:

- Name: Gartenacker
- Sampling location: Les Barges, Switzerland
- GPS Coordinates of collection site: 46.3313 N, 6.9241 E
- Date of collection: 15-September-2011
- Pesticide History: No pesticide use in the last 5 years
- Sampling depth: 5-20 cm
- Storage conditions: ~4ºC
- Soil preparation: Moist soil screened through 2mm sieve
- Particle size: 5 % w/w clay (<2 µm); 54 % w/w silt (50-2 µm); 41 % w/w sand (2000-50 µm)
- Texture (USDA): Silt Loam
- pH (water) 1:1 (soil to water weight ratio): 7.2
- pH (0.01M CaCl2) 1:1: 7.0
- Organic matter: 4.7 %
- Organic carbon: 2.7 %
- CEC: 11.6 meq/100 g soil
- Moisture at pF2.0 (0.1bar): 35.7 w/w %
- Bulk density: 0.93 gm/cc
- Microbial Biomass at start of study: 420.8 µg carbon/g soil dry basis

Light source:

Xenon lamp

Remarks:

equipped with filters to eliminate wavelengths < 290 nm

Light spectrum: wavelength in nm:

>= 290 - <= 800

Details on light source:

Similar spectral distribution to natural sunlight

Details on test conditions:

- Duration of the test: 15 days (equivalent of 30 days natural summer sunlight)
- Soil condition: Fresh soil, passed through 2 mm sieve prior to use
- Soil sample weight: 2 g (dry weight) per replicate
- Test concentration (mg/kg soil (dry weight)): Approximately 36.732 μg/g for [14C-phenyl] and approximately 37.776 μg/g for [14C-triazolyl] (Note: ~35 μg/g = 250 g/ha)
- Control conditions: Darkness
- Number of replicates irradiated: 2
- Number of replicates darkness: 2
- Test apparatus irradiated: Quartz vessels
- Test apparatus darkness: 125 mL size glass bottles, moist air flow through system under vacuum
- Traps for CO2 & organic volatiles: One trap of ethylene glycol (for organic volatiles) followed by two 1N NaOH traps (for CO2)
- Identity of solvent: Dosed in acetonitrile
- Volume of test solution used/treatment: 29.5 μL for [14C-Phenyl] and 39.0 μL for [14C-Triazolyl]
- Application method: 50 μL gas tight syringe
- Evaporation of application solvent: Yes
- Indication of test material adsorbing to walls of test apparatus: No
- Temperature: 20 ± 2 °C
- Continuous irradiation: Yes
- Moisture content: At Day 0, moist soil adjusted to pF2 and monitored throughout the experiment every 2-3 days. No adjustment made to dry soil at Day 0

Duration:

15

% Moisture:

35.7

Temp.:

20 °C

Initial conc. measured:

35 mg/kg soil d.w.

Duration:

15 d

% Moisture:

0

Temp.:

20 °C

Initial conc. measured:

35 mg/kg soil d.w.

Reference substance:

no

Dark controls:

yes

Computational methods:

CAKE Version 1.3 (released) running on R Version 2.12.2 (2011-02-25)

Test performance:

The radiochemical purity value experimentally determined for [14C-phenyl]-test substance and [14C-triazolyl]-test substance was 96.6% and 98.2%, respectively.

% Degr.:

15.52

Sampling time:

15 d

Test condition:

Irradiated moist soil

Remarks on result:

other: 14C-phenyl labelled

% Degr.:

13.42

Sampling time:

15 d

Test condition:

Irradiated moist soil

Remarks on result:

other: 14C-triazolyl labelled

% Degr.:

7.54

Sampling time:

15 d

Test condition:

Dark control moist soil

Remarks on result:

other: 14C-phenyl labelled

% Degr.:

8.28

Sampling time:

15 d

Test condition:

Dark control moist soil

Remarks on result:

other: 14C-triazolyl labelled

% Degr.:

16.41

Sampling time:

15 d

Test condition:

Irradiated dry soil

Remarks on result:

other: 14C-phenyl labelled

% Degr.:

14.5

Sampling time:

15 d

Test condition:

Irradiated dry soil

Remarks on result:

other: 14C-triazolyl labelled

% Degr.:

8.64

Sampling time:

15 d

Test condition:

Dark control dry soil

Remarks on result:

other: 14C-phenyl labelled

% Degr.:

2.41

Sampling time:

15 d

Test condition:

Dark control dry soil

Remarks on result:

other: 14C-triazolyl labelled

DT50:

80 d

Test condition:

Irradiated moist soil

Remarks on result:

other: Artificial light

DT50:

66 d

Test condition:

Irradiated dry soil

Remarks on result:

other: Artificial light

Key result

DT50:

162 d

Test condition:

Irradiated moist soil

Remarks on result:

other: Corrected to natural summer sunlight 30-50 °N

Key result

DT50:

133 d

Test condition:

Irradiated dry soil

Remarks on result:

other: Corrected to natural summer sunlight 30-50 °N

Transformation products:

yes

No.:

#1

No.:

#2

No.:

#3

No.:

#4

Details on results:

MOIST SOIL
- Mass Balance: The mass balance for irradiated moist soil samples treated with 14C-phenyl labelled test substance ranged from 99.3 - 108.1% (mean 103.5%). The mass balance for irradiated moist soil samples treated with 14C-triazolyl labelled test substance ranged from 99.5 – 108.5% (mean 104.2%).
The mass balance for dark control moist soil samples treated with 14C-phenyl labelled test substance ranged from 90.9 – 108.2% (mean 101.9%). The mass balance for dark control samples treated with 14C-triazolyl labelled test substance ranged from 97.7 – 106.5% (mean 102.4%).

- Volatile Degradation Products: Percentages of 14CO2 evolved at the end of the study were 1.4% and 0.3% in irradiated moist soil treated with 14C-phenyl labelled test substance and 14C-triazolyl labelled test substance, respectively.
Percentages of 14CO2 evolved at the end of the study were 0.4% and 0.1% in dark control moist soil treated with 14C-phenyl labelled test substance and 14C-triazolyl labelled test substance, respectively.
No other volatiles were observed.

- Photodegradation of the Test Substance: The amount of test substance declined slowly from an average of 99.8% on Day 0 to an average of 84.5% AR at Day 15 for the irradiated moist soil samples treated with [14C-phenyl]-test substance (as compared to the dark control samples that contained an average of 92.5% AR at Day 15). Trans-M5 reached a maximum of 5.7% by Day 15. M1, M2, and cis-M5 were present but none of these transformation products exceeded 5% AR except trans-M5. Similarly, trans-M5 was a transformation product in the dark control test system, present at an average maximum of 5.5% AR by Day 15. M1, M2, and cis-M5 were also present in the dark control test system but none exceeded 5% AR.

The amount of test substance declined slowly from an average of 96.9% on Day 0 to an average of 86.6% AR at Day 15 for the irradiated moist soil samples treated with [14C-triazolyl]-test substance (as compared to the dark control samples that contained 91.7% AR at Day 15). M4, trans-M5 and cis-M5 were present but none exceeded 5% except M4. M4 reached an average maximum on Day 1 with 5.0% AR. The identified degradates, M4 and M2, were the transformation products present in the dark control test system. M2 did not exceed 5% AR. M4 reached an average maximum of 6.0% AR on Day 15.

The minor presence of degradates at Day 0 (in the presence and absence of light) may be attributed to the obvious impurity for the [14C-phenyl] and [14C-triazolyl]-test substance treated samples.

DRY SOIL
- Mass Balance: The mass balance for irradiated dry soil samples treated with 14C-phenyl labelled test substance ranged from 94.1 – 106.9% (mean 102.5%). The mass balance for irradiated dry soil samples treated with 14C-triazolyl labelled test substance ranged from 100.8 – 108.1% (mean 105.2%).
The mass balance for dark control dry soil samples treated with 14C-phenyl labelled test substance ranged from 96.7 – 107.1% (mean 103.5%). The mass balance for dark control samples treated with 14C-triazolyl labelled test substance ranged from 98.7 – 109.6% (mean 103.9%).

- Volatile Degradation Products: Percentages of 14CO2 evolved at the end of the study were 1.4% and 0.3% in irradiated dry soil treated with 14C-phenyl labelled test substance and 14C-triazolyl labelled test substance, respectively.
The percentage of 14CO2 evolved at the end of the study was 0.1% in dark control dry soil treated with both 14C-phenyl labelled test substance and 14C-triazolyl labelled test substance.
No other volatiles were observed.

- Photodegradation of the Test Substance: The amount of test substance declined slowly from an average of 99.8% on Day 0 to an average of 84.5% AR at Day 15 for the irradiated dry soil samples treated with [14C-phenyl]-test substance (as compared to the dark control samples that contained an average of 92.5% AR at Day 15). Trans-M5 reached a maximum of 5.7% by Day 15. M1, M2, and cis-M5 were present but none of these transformation products exceeded 5% AR, except trans-M5. Similarly, trans-M5 was a transformation product in the dark control test system, present at an average maximum of 5.5% AR by Day 15. M1, M2, and cis-M5 were also present in the dark control test system but none exceeded 5% AR.

The amount of test substance declined slowly from an average of 96.9% on Day 0 to an average of 86.6% AR at Day 15 for the irradiated dry soil samples treated with [14C-triazolyl]-test substance (as compared to the dark control samples that contained 91.7% AR at Day 15). M4, trans-M5 and cis-M5 were present but none exceeded 5% except M4. M4 reached an average maximum on Day 1 with 5.0% AR. The identified degradates, M4 and M2, were the transformation products present in the dark control test system. M2 did not exceed 5% AR. M4 reached an average maximum of 6.0% AR on Day 15.

The minor presence of degradates at Day 0 (in the presence and absence of light) may be attributed to the obvious impurity for the [14C-phenyl] and [14C-triazolyl]-test substance treated samples.

Table 2, Distribution and Recovery of test substance in the Irradiated Moist Soil Photolysis Samples Treated with [14C-phenyl]-test substance as Percent of Applied Radioactivity

14C-phenyl-test substance	Rep	Sampling time (days)
		Day 0	Day 0.17	Day 1	Day 3	Day 6	Day 10	Day 15
Total extractables	A	104.40	104.27	96.94	104.97	96.08	96.77	92.42
	B	100.47	101.16	98.58	105.01	101.29	98.93	96.66
	Mean	102.43	102.72	97.76	104.99	98.68	97.85	94.54
Non-extractables	A	0.39	1.86	2.34	3.09	4.05	3.55	7.21
	B	0.62	1.80	2.40	2.85	3.46	4.37	6.23
	Mean	0.50	1.83	2.37	2.97	3.76	3.96	6.72
14CO2	A	na	na	0.06	0.24	0.54	1.07	1.40
	B	na	na	0.06	0.24	0.54	1.07	1.40
	Mean	na	na	0.06	0.24	0.54	1.07	1.40
Other volatiles	A	na	na	nd	nd	nd	nd	nd
	B	na	na	nd	nd	nd	nd	nd
	Mean	na	na	nd	nd	nd	nd	nd
Total % recovery	A	104.79	106.13	99.33	108.30	100.68	101.39	101.04
	B	101.09	102.96	101.04	108.10	105.29	104.37	104.29
	Mean	102.94	104.55	100.19	108.20	102.98	102.88	102.67
Overall mean ± SD		103.49% ± 2.85%

 

Table 3, Distribution and Recovery of test substance in the Irradiated Moist Soil Photolysis Samples Treated with [14C-triazolyl]-test substance as Percent of Applied Radioactivity

14C-triazolyl-test substance	Rep	Sampling time (days)
		Day 0	Day 0.17	Day 1	Day 3	Day 6	Day 10	Day 15
Total extractables	A	98.95	104.25	98.41	104.20	103.84	98.17	99.25
	B	102.80	100.94	100.92	103.85	102.59	95.59	98.28
	Mean	100.88	102.60	99.66	104.02	103.22	96.88	98.76
Non-extractables	A	0.53	1.38	2.29	3.85	4.51	3.44	5.57
	B	0.53	1.35	2.36	3.07	4.68	4.43	6.67
	Mean	0.53	1.36	2.32	3.46	4.60	3.93	6.12
14CO2	A	na	na	0.04	0.07	0.11	0.18	0.27
	B	na	na	0.04	0.07	0.11	0.18	0.27
	Mean	na	na	0.04	0.07	0.11	0.18	0.27
Other volatiles	A	na	na	nd	nd	nd	nd	nd
	B	na	na	nd	nd	nd	nd	nd
	Mean	na	na	nd	nd	nd	nd	nd
Total % recovery	A	99.48	105.63	100.74	108.12	108.47	101.79	105.08
	B	103.34	102.29	103.33	106.99	107.39	100.20	105.23
	Mean	101.41	103.96	102.03	107.55	107.93	100.99	105.16
Overall mean ± SD		104.15% ± 3.00%

 

Table 4, Distribution and Recovery of test substance in the Dark Control Moist Soil Photolysis Samples Treated with [14C-phenyl]-test substance as Percent of Applied Radioactivity

14C-phenyl-test substance	Rep	Sampling time (days)
		Day 0	Day 0.17	Day 1	Day 3	Day 6	Day 10	Day 15
Total extractables	A	96.86	103.38	102.20	103.44	102.33	96.29	97.44
	B	101.09	89.98	101.81	100.14	106.08	101.05	98.45
	Mean	98.97	96.68	102.00	101.79	104.21	98.67	97.95
Non-extractables	A	0.37	1.05	1.60	1.74	1.94	2.29	3.19
	B	0.41	0.95	1.56	1.86	1.96	2.54	3.20
	Mean	0.39	1.00	1.58	1.80	1.95	2.41	3.19
14CO2	A	na	na	0.03	0.09	0.17	0.29	0.38
	B	na	na	0.03	0.09	0.17	0.29	0.38
	Mean	na	na	0.03	0.09	0.17	0.29	0.38
Other volatiles	A	na	na	na	na	na	na	na
	B	na	na	na	na	na	na	na
	Mean	na	na	na	na	na	na	na
Total % recovery	A	97.23	104.44	103.82	105.27	104.46	98.88	101.01
	B	101.50	90.94	103.39	102.09	108.23	103.88	102.04
	Mean	99.36	97.69	103.61	103.68	106.34	101.38	101.52
Overall mean ± SD		101.94% ± 4.17%

 

Table 5, Distribution and Recovery of test substance in the Dark Control Moist Soil Photolysis Samples Treated with [14C-triazolyl]-test substance as Percent of Applied Radioactivity

14C-triazolyl-test substance	Rep	Sampling time (days)
		Day 0	Day 0.17	Day 1	Day 3	Day 6	Day 10	Day 15
Total extractables	A	98.88	102.36	100.60	100.13	101.72	99.30	94.60
	B	101.45	105.66	101.96	102.72	100.95	95.31	100.91
	Mean	100.17	104.01	101.28	101.42	101.34	97.31	97.76
Non-extractables	A	0.38	0.87	1.74	2.40	2.39	2.70	2.96
	B	0.37	0.80	1.56	2.10	2.56	2.77	2.96
	Mean	0.37	0.83	1.65	2.25	2.48	2.73	2.96
14CO2	A	na	na	0.02	0.04	0.05	0.07	0.12
	B	na	na	0.02	0.04	0.05	0.07	0.12
	Mean	na	na	0.02	0.04	0.05	0.07	0.12
Other volatiles	A	na	na	na	na	na	na	na
	B	na	na	na	na	na	na	na
	Mean	na	na	na	na	na	na	na
Total % recovery	A	99.26	103.23	102.35	102.56	104.17	102.07	97.68
	B	101.82	106.46	103.54	104.86	103.55	98.15	104.00
	Mean	100.54	104.84	102.95	103.71	103.86	100.11	100.84
Overall mean ± SD		102.41% ± 2.51%

 

Table 6, Distribution and Recovery of test substance in the Irradiated Dry Soil Photolysis Samples Treated with [14C-phenyl]-test substance as Percent of Applied Radioactivity

14C-phenyl-test substance	Rep	Sampling time (days)
		Day 0	Day 0.17	Day 1	Day 3	Day 6	Day 10	Day 15
Total extractables	A	101.94	96.99	100.95	103.40	94.79	99.41	97.84
	B	105.68	92.78	104.00	102.18	97.77	91.90	91.35
	Mean	103.81	94.88	102.48	102.79	96.28	95.65	94.60
Non-extractables	A	0.24	1.67	2.53	3.32	4.43	4.35	5.38
	B	0.40	1.35	1.53	2.96	3.69	7.45	8.22
	Mean	0.32	1.51	2.03	3.14	4.02	5.90	6.80
14CO2	A	na	na	0.05	0.17	0.52	0.93	1.38
	B	na	na	0.05	0.17	0.52	0.93	1.38
	Mean	na	na	0.05	0.17	0.52	0.93	1.38
Other volatiles	A	na	na	nd	nd	nd	nd	nd
	B	na	na	nd	nd	nd	nd	nd
	Mean	na	na	nd	nd	nd	nd	nd
Total % recovery	A	102.18	98.66	103.53	106.89	99.65	104.69	104.60
	B	106.08	94.13	105.57	105.31	101.97	100.28	100.95
	Mean	104.13	96.40	104.55	106.10	100.81	102.48	102.77
Overall mean ± SD		102.46% ± 3.51%

 

Table 7, Distribution and Recovery of test substance in the Irradiated Dry Soil Photolysis Samples Treated with [14C-triazolyl]-test substance as Percent of Applied Radioactivity

14C-triazolyl-test substance	Rep	Sampling time (days)
		Day 0	Day 0.17	Day 1	Day 3	Day 6	Day 10	Day 15
Total extractables	A	101.18	101.40	105.66	103.72	98.81	93.75	95.71
	B	104.29	104.98	105.12	101.23	102.02	92.93	95.98
	Mean	102.73	103.19	105.39	102.47	100.41	93.07	95.84
Non-extractables	A	0.42	1.17	2.10	4.31	6.67	8.81	9.62
	B	0.38	1.33	2.36	3.70	4.57	8.20	11.31
	Mean	0.40	1.25	2.23	4.00	5.62	8.50	10.47
14CO2	A	na	na	0.02	0.06	0.12	0.24	0.31
	B	na	na	0.02	0.06	0.12	0.24	0.31
	Mean	na	na	0.02	0.06	0.12	0.24	0.31
Other volatiles	A	na	na	nd	nd	nd	nd	nd
	B	na	na	nd	nd	nd	nd	nd
	Mean	na	na	nd	nd	nd	nd	nd
Total % recovery	A	101.60	102.58	107.79	108.08	105.60	102.79	105.63
	B	104.67	106.31	107.50	104.98	106.71	100.82	107.59
	Mean	103.14	104.44	107.64	106.53	106.15	101.81	106.61
Overall mean ± SD		105.19% ± 2.40%

 

Table 8, Distribution and Recovery of test substance in the Dark Control Dry Soil Photolysis Samples Treated with [14C-phenyl]-test substance as Percent of Applied Radioactivity

14C-phenyl-test substance	Rep	Sampling time (days)
		Day 0	Day 0.17	Day 1	Day 3	Day 6	Day 10	Day 15
Total extractables	A	101.49	96.29	100.49	105.70	103.01	102.26	99.01
	B	104.80	106.72	102.23	105.96	104.08	102.09	101.01
	Mean	103.14	101.50	101.36	105.83	103.55	102.17	100.01
Non-extractables	A	0.24	0.45	0.59	0.94	1.23	1.41	2.08
	B	0.22	0.41	0.64	0.93	1.18	1.52	2.16
	Mean	0.23	0.43	0.62	0.94	1.21	1.47	2.12
14CO2	A	na	na	0.01	0.02	0.03	0.05	0.11
	B	na	na	0.01	0.02	0.03	0.05	0.11
	Mean	na	na	0.01	0.02	0.03	0.05	0.11
Other volatiles	A	na	na	na	na	na	na	na
	B	na	na	na	na	na	na	na
	Mean	na	na	na	na	na	na	na
Total % recovery	A	101.73	96.74	101.10	106.67	104.28	103.72	101.20
	B	105.02	107.13	102.89	106.92	105.29	103.66	103.27
	Mean	103.37	101.94	101.99	106.80	104.79	103.69	102.24
Overall mean ± SD		103.54% ± 2.79%

 

Table 9, Distribution and Recovery of test substance in the Dark Control Dry Soil Photolysis Samples Treated with [14C-triazolyl]-test substance as Percent of Applied Radioactivity

14C-triazolyl-test substance	Rep	Sampling time (days)
		Day 0	Day 0.17	Day 1	Day 3	Day 6	Day 10	Day 15
Total extractables	A	101.96	107.78	100.58	102.89	100.27	96.23	101.84
	B	102.23	108.81	102.93	100.62	106.19	98.61	100.27
	Mean	102.09	108.29	101.75	101.76	103.23	97.42	101.05
Non-extractables	A	0.45	0.77	1.32	1.70	2.26	2.41	2.50
	B	0.51	0.74	1.22	1.83	2.33	1.89	2.55
	Mean	0.48	0.75	1.27	1.77	2.29	2.15	2.53
14CO2	A	na	na	0.02	0.03	0.04	0.05	0.08
	B	na	na	0.02	0.03	0.04	0.05	0.08
	Mean	na	na	0.02	0.03	0.04	0.05	0.08
Other volatiles	A	na	na	na	na	na	na	na
	B	na	na	na	na	na	na	na
	Mean	na	na	na	na	na	na	na
Total % recovery	A	102.41	108.55	101.92	104.63	102.57	98.68	104.42
	B	102.74	109.55	104.17	102.49	108.56	100.55	102.90
	Mean	102.57	109.05	103.05	103.56	105.57	99.61	103.66
Overall mean ± SD		103.87% ± 3.12%

Table 10, Quantification of the test substance and its Photodegradates: Irradiated Moist Soil Photolysis Samples Treated with [14C-phenyl]-test substance

14C-phenyl-test substance	Rep	Sampling time (days)
		Day 0	Day 0.17	Day 1	Day 3	Day 6	Day 10	Day 15
Test substance	A	102.43	100.92	93.71	101.32	93.29	93.02	80.90
	B	97.25	98.95	96.52	103.34	99.59	94.23	88.05
	Mean	99.84	99.94	95.12	102.33	96.44	93.63	84.48
M1	A	ND	ND	ND	ND	ND	ND	1.20
	B	ND	ND	ND	ND	ND	ND	1.41
	Mean	ND	ND	ND	ND	ND	ND	1.31
Trans-M5	A	1.96	1.35	1.74	2.37	1.99	3.75	6.40
	B	1.71	ND	0.64	0.95	1.70	4.70	4.92
	Mean	1.84	0.67	1.19	1.66	1.85	4.23	5.66
M2	A	ND	2.00	1.48	1.28	0.81	ND	ND
	B	1.52	2.21	1.42	0.71	ND	ND	ND
	Mean	0.76	2.10	1.45	1.00	0.40	ND	ND
Cis-M5	A	ND	ND	ND	ND	ND	ND	3.14
	B	ND	ND	ND	ND	ND	ND	0.87
	Mean	ND	ND	ND	ND	ND	ND	2.01
Others	A	ND	ND	ND	ND	ND	ND	0.79
	B	ND	ND	ND	ND	ND	ND	1.40
	Mean	ND	ND	ND	ND	ND	ND	1.09

 

Table 11, Quantification of the test substance and its Photodegradates: Irradiated Moist Soil Photolysis Samples Treated with [14C-triazolyl]-test substance as Percent of Applied Radioactivity

14C-triazolyl-test substance	Rep	Sampling time (days)
		Day 0	Day 0.17	Day 1	Day 3	Day 6	Day 10	Day 15
Test substance	A	94.89	99.57	92.61	98.11	97.25	90.40	88.34
	B	98.81	97.30	96.68	100.21	94.95	88.53	84.83
	Mean	96.85	98.43	94.65	99.16	96.10	89.47	86.58
M4	A	2.45	4.68	5.80	6.09	4.04	3.41	4.47
	B	2.56	3.64	4.24	3.63	4.35	3.37	4.81
	Mean	2.51	4.16	5.02	4.86	4.19	3.39	4.64
Trans-M5	A	ND	ND	ND	ND	0.92	1.84	2.58
	B	ND	ND	ND	ND	1.28	1.48	4.41
	Mean	ND	ND	ND	ND	1.10	1.66	3.50
M2	A	1.60	ND	ND	ND	ND	ND	ND
	B	1.44	ND	ND	ND	ND	ND	ND
	Mean	1.52	ND	ND	ND	ND	ND	ND
Cis-M5	A	ND	ND	ND	ND	1.63	1.77	3.30
	B	ND	ND	ND	ND	2.02	2.20	4.24
	Mean	ND	ND	ND	ND	1.83	1.98	3.77
Others	A	ND	ND	ND	ND	ND	0.77	0.56
	B	ND	ND	ND	ND	ND	0.00	0.00
	Mean	ND	ND	ND	ND	ND	0.38	0.28

 

Table 12, Quantification of the test substance and its Photodegradates: Dark Control Moist Soil Photolysis Samples Treated with [14C-phenyl]-test substance as Percent of Applied Radioactivity

14C-phenyl-test substance	Rep	Sampling time (days)
		Day 0	Day 0.17	Day 1	Day 3	Day 6	Day 10	Day 15
Test substance	A	94.07	99.07	98.35	98.48	100.60	88.05	92.10
	B	97.55	86.89	96.85	95.06	102.44	92.97	92.87
	Mean	95.81	92.98	97.60	96.77	101.52	90.51	92.46
M1	A	ND	ND	1.37	0.63	ND	1.07	ND
	B	ND	ND	0.76	ND	0.84	1.32	ND
	Mean	ND	ND	1.07	0.32	0.42	1.20	ND
Trans-M5	A	ND	2.46	2.47	4.32	1.73	5.65	5.34
	B	1.09	1.44	4.19	5.08	2.81	2.88	5.58
	Mean	0.55	1.95	3.33	4.70	2.27	4.27	5.46
M2	A	2.79	1.85	ND	ND	ND	0.89	ND
	B	2.45	1.66	ND	ND	ND	ND	ND
	Mean	2.62	1.75	ND	ND	ND	0.44	ND
Cis-M5	A	ND	ND	ND	ND	ND	ND	ND
	B	ND	ND	ND	ND	ND	1.96	ND
	Mean	ND	ND	ND	ND	ND	0.98	ND
Others	A	ND	ND	ND	ND	ND	0.64	ND
	B	ND	ND	ND	ND	ND	1.91	ND
	Mean	ND	ND	ND	ND	ND	1.27	ND

 

Table 13, Quantification of the test substance and its Photodegradates: Dark Control Moist Soil Photolysis Samples Treated with [14C-triazolyl]-test substance as Percent of Applied Radioactivity

14C-triazolyl-test substance	Rep	Sampling time (days)
		Day 0	Day 0.17	Day 1	Day 3	Day 6	Day 10	Day 15
Test substance	A	94.00	98.50	94.48	95.60	97.25	94.76	89.71
	B	94.72	101.66	97.60	99.73	97.44	89.84	93.74
	Mean	94.36	100.08	96.04	97.66	97.34	92.30	91.72
M4	A	2.35	3.86	6.12	4.53	3.73	4.55	4.89
	B	3.59	3.99	4.36	2.99	3.51	5.47	7.17
	Mean	2.97	3.93	5.24	3.76	3.62	5.01	6.03
M2	A	2.53	ND	ND	ND	ND	ND	ND
	B	3.13	ND	ND	ND	ND	ND	ND
	Mean	2.83	ND	ND	ND	ND	ND	ND
Others	A	ND	ND	ND	ND	0.74	ND	ND
	B	ND	ND	ND	ND	ND	ND	ND
	Mean	ND	ND	ND	ND	0.37	ND	ND

 

Table 14, Quantification of the test substance and its Photodegradates: Irradiated Dry Soil Photolysis Samples Treated with [14C-phenyl]-test substance as Percent of Applied Radioactivity

14C-phenyl-test substance	Rep	Sampling time (days)
		Day 0	Day 0.17	Day 1	Day 3	Day 6	Day 10	Day 15
Test substance	A	98.70	93.30	96.18	99.29	91.11	94.42	85.63
	B	102.97	87.09	98.88	99.31	94.62	77.12	81.55
	Mean	100.84	90.19	97.53	99.30	92.87	85.77	83.59
Trans-M5	A	ND	1.95	3.91	2.94	3.68	4.99	12.21
	B	ND	1.96	4.06	2.30	3.15	13.12	9.80
	Mean	ND	1.95	3.98	2.62	3.41	9.06	11.01
M2	A	3.23	1.74	0.87	1.17	ND	ND	ND
	B	2.71	2.51	1.06	0.57	ND	1.65	ND
	Mean	2.97	2.13	0.96	0.87	ND	0.83	ND
Others	A	ND	ND	ND	ND	ND	ND	ND
	B	ND	ND	ND	ND	ND	ND	ND
	Mean	ND	ND	ND	ND	ND	ND	ND

 

Table 15, Quantification of the test substance and its Photodegradates: Irradiated Dry Soil Photolysis Samples Treated with [14C-triazolyl]-test substance as Percent of Applied Radioactivity

14C-triazolyl-test substance	Rep	Sampling time (days)
		Day 0	Day 0.17	Day 1	Day 3	Day 6	Day 10	Day 15
Test substance	A	96.44	95.58	101.38	98.33	90.33	90.83	87.62
	B	99.05	100.08	102.25	96.70	99.07	84.98	83.39
	Mean	97.75	97.83	101.82	97.51	94.70	87.91	85.50
M4	A	2.32	3.40	4.28	5.38	8.48	2.92	8.09
	B	1.85	2.89	2.87	4.54	2.95	7.41	12.59
	Mean	2.08	3.14	3.57	4.96	5.71	5.16	10.34
M2	A	2.43	2.42	ND	ND	ND	ND	ND
	B	3.39	2.02	ND	ND	ND	ND	ND
	Mean	2.91	2.22	ND	ND	ND	ND	ND
Others	A	ND	ND	ND	ND	ND	ND	ND
	B	ND	ND	ND	ND	ND	ND	ND
	Mean	ND	ND	ND	ND	ND	ND	ND

 

Table 16, Quantification of the test substance and its Photodegradates: Dark Control Dry Soil Photolysis Samples Treated with [14C-phenyl]-test substance as Percent of Applied Radioactivity

14C-phenyl-test substance	Rep	Sampling time (days)
		Day 0	Day 0.17	Day 1	Day 3	Day 6	Day 10	Day 15
Test substance	A	99.46	93.18	97.21	102.31	101.58	98.01	87.99
	B	101.81	103.22	99.64	103.43	102.11	96.87	94.72
	Mean	100.64	98.20	98.42	102.87	101.85	97.44	91.36
M1	A	0.00	ND	ND	ND	ND	ND	2.31
	B	ND	ND	ND	ND	ND	ND	1.21
	Mean	ND	ND	ND	ND	ND	ND	1.76
Trans-M5	A	2.03	1.15	1.32	3.39	1.43	4.24	3.98
	B	1.57	1.01	0.83	1.64	1.97	5.22	5.07
	Mean	1.80	1.08	1.07	2.52	1.70	4.73	4.53
M2	A	0.00	1.95	1.97	ND	ND	ND	ND
	B	1.40	2.49	1.75	0.89	ND	ND	ND
	Mean	0.70	2.22	1.86	0.45	ND	ND	ND
Cis-M5	A	0.00	ND	ND	ND	ND	ND	2.37
	B	ND	ND	ND	ND	ND	ND	ND
	Mean	ND	ND	ND	ND	ND	ND	1.18
Others	A	ND	ND	ND	ND	ND	ND	2.37
	B	ND	ND	ND	ND	ND	ND	ND
	Mean	ND	ND	ND	ND	ND	ND	1.18

 

Table 17, Quantification of the test substance and its Photodegradates: Dark Control Dry Soil Photolysis Samples Treated with [14C-triazolyl]-test substance as Percent of Applied Radioactivity

14C-triazolyl-test substance	Rep	Sampling time (days)
		Day 0	Day 0.17	Day 1	Day 3	Day 6	Day 10	Day 15
Test substance	A	96.06	101.61	97.01	99.55	97.36	93.62	98.49
	B	98.16	104.29	99.18	98.42	102.80	95.19	96.70
	Mean	97.11	102.95	98.09	98.98	100.08	94.40	97.59
M4	A	2.85	4.25	3.57	3.34	2.91	2.61	3.35
	B	2.03	3.30	3.76	2.20	3.39	3.42	3.57
	Mean	2.44	3.77	3.66	2.77	3.15	3.01	3.46
M2	A	3.04	1.92	ND	ND	ND	ND	ND
	B	2.05	1.22	ND	ND	ND	ND	ND
	Mean	2.55	1.57	ND	ND	ND	ND	ND
Others	A	ND	ND	ND	ND	ND	ND	ND
	B	ND	ND	ND	ND	ND	ND	ND
	Mean	ND	ND	ND	ND	ND	ND	ND

Table 18, Summary of DegT50 and DegT90 Values

	14C-test substance*
	Dry soil			Moist soil
	DegT50 (days)	Deg T90 (days)	Chi2	DegT50 (days)	Deg T90 (days)	Chi2
Irradiated	66	219	1.969	80	267	1.907
Corrected DT50 and DegT90**
Natural summer sunlight 30-50 °N	133	441	1.970	162	538	1.906

* Data reported calculated from individual replicate values for irradiated soil labelled with both [14C-phenyl]-test substance and [14C-triazolyl]-test substance.

** Corrected values are calculated using a mean value of 67 W/m2 to represent the irradiance (300-400 nm) of natural summer sunlight for latitudes of 30-50 °N as derived from the 2002 OECD Draft Guidance on the Phototransformation of Chemicals on Soil Surfaces

Validity criteria fulfilled:

not specified

Conclusions:

In a phototransformation study in soil that was performed in accordance with OECD TG draft, OPPTS 835.2410 and ECC Directive 95/36/EC guidelines, the DegT50 of the test substance was determined to be 66 days (dry soil, artificial continuous light) which, was equivalent to 133 days when corrected to natural summer sunlight (30-50 °N). For moist soil the DegT50 was determined to be 80 days (artificial continuous light) which, was equivalent to 162 days when corrected to natural summer sunlight (30-50 °N).

Executive summary:

The soil photodegradation of the test substance was determined in a study that was performed according to the OECD TG draft, OPPTS 835.2410, and ECC Directive 95/36/EC guidelines and in compliance with GLP criteria. The photolysis of the radiolabeled test substance was determined using simulated sunlight from a xenon arc lamp. In this study, [14C-phenyl] and [14C-triazolyl]-labelled test substances were applied separately at approximately 70.7 µg per vessel (equivalent to single maximum label rate of 250 g/ha) to moist and dry soil to investigate the influence of exposure to sunlight on the rate and route of degradation. Samples were subjected to continuous irradiation for 15 days using artificial sunlight and maintained at 20 ± 2 °C. Duplicate irradiated and dark control soil samples were assayed at 7 intervals following the application of the test substance. Control samples maintained at 20 ± 2 °C were incubated in the dark and sampled for analysis at intervals equivalent to those in the irradiated test.

The overall mass balance of radioactivity for the irradiated samples throughout the study ranged from 94.1 to 108.5% of the applied radioactivity AR. Similarly, the mass balance for the dark control samples ranged from 90.9 to 109.6% AR. Under moist irradiated conditions, average levels of [14C-phenyl]-test substance declined from 99.8% AR on Day 0 to 84.5% AR by Day 15. In comparison, the dark control samples declined little from 95.8% AR on Day 0 to 92.5% by Day 15. The primary transformation products in the moist, irradiated test system were M1, M2, cis-M5 and trans-M5. None of the transformation products exceeded 5% except the trans-M5 which reached a mean maximum of 5.6% on Day 15.
Under dry, irradiated conditions, average levels of [14C-phenyl]-test substance declined from 100.8% AR on Day 0 to 83.6% AR by Day 15. In comparison, the dark control samples declined from 100.6% AR on Day 0 to 91.4% by Day 15. The primary transformation products in the dry, irradiated test system were M2 and trans-M5. M2 did not exceed 5% during the incubation period. Trans-M5 reached a maximum of 11.0% by Day 15.
Under moist irradiated conditions, average levels of [14C-triazolyl]-test substance declined from 96.8% AR on Day 0 to 86.6% AR by Day 15. In comparison, the dark control samples declined from 94.4% AR on Day 0 to 91.7% by Day 15. The primary transformation products in the moist, irradiated test system were M4 and cis-M5 as well as trans-M5. M4 reached a maximum of 5.0% on Day 1. Cis-M5 and trans-M5 levels did not exceed 5% during the incubation period.
Under dry, irradiated conditions, average levels of [14C-triazolyl]-test substance declined from 97.8% AR on Day 0 to 85.5% AR by Day 15. In comparison, levels of [14C-triazolyl]-test substance in the dark control samples remained constant throughout the incubation period at about 97% AR. The primary transformation products in the dry, irradiated test system were M4 and M2. M4 reached a maximum of 10.3% by Day 15. M2 did not exceed 5% during the incubation period.
Carbon dioxide was a minor product of metabolism, reaching an average maximum of 1.4% AR by the end of all incubations in irradiated (phenyl treated moist and dry). The amount of test substance mass extracted from the soil decreased over time. The rate of degradation in moist and dry irradiated soil was estimated using single first-order (SFO) kinetics. The regression analyses were also evaluated using the exposure time adjusted to the intensity of natural sunlight at 30-50 ºN latitude. The test substance degraded moderately when irradiated by simulated sunlight (DegT50 is 66 days in dry soil and 80 days in moist soil). When adjusted to natural summer sunlight at latitudes of 30-50 °N the DegT50 is 133 days in dry soil and 162 days in moist soil. Based on the results of this study, soil photolysis is unlikely to be a major route of eliminating the test substance from the environment.

Description of key information

All available data was assessed and the study representing the worst-case effects was included as the key study. Other studies are included as supporting information. The effect value which is considered to be the worst-case is selected for the CSA.

DT50 = 162 days, adjusted to natural summer sunlight at 30-50°N, 20 °C, OECD TG draft, OPPTS 835.2410 and ECC Directive 95/36/EC guidelines, 14C-phenyl and 14C-triazolyl labelled test substance, Miner 2013

Key value for chemical safety assessment

Half-life in soil:

162 d

Additional information

Three studies on photodegradation in soil using a xenon arc lamp are available for this endpoint. All three are reliability 1 studies and performed according to standard guidelines and under GLP. The study representing the worst-case effect (i.e. showed the highest DT50 value) was included as the key study. In the key study (Miner 2013), 14C-phenyl and 14C-triazolyl-labelled test substance was applied separately at approximately 70.7 µg per vessel (equivalent to single maximum label rate of 250 g/ha) to moist and dry soil under continuous irradiation for 15 days and maintained at 20 ± 2 °C. When adjusted to natural summer sunlight at latitudes of 30-50 °N the DegT50 is 133 days in dry soil and 162 days in moist soil.

In the supporting studies (Spare 1991 and Saxena 1989, both reliability 1), the calculated half-life in moist soil was approximately 150 days (14C-phenyl ring-labelled test substance, 25 ± 1°C for 30 days) and 52.6 artificial sunlight days or 23.9 natural sunlight days (triazole-(ring-UL-14C)-labelled test substance, 25.6°C for 30 days), assuming 12 hours of light per day.