heptan-2-yl [(5-chloroquinolin-8-yl)oxy]acetate

Phototransformation in water

Link to relevant study record(s)

Reference

Endpoint:

phototransformation in water

Type of information:

experimental study

Adequacy of study:

key study

Study period:

11 June - 20 November 1990

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Study type:

direct photolysis

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
Not applicable.

Radiolabelling:

yes

Analytical method:

high-performance liquid chromatography

other: TLC

Details on sampling:

- Sampling intervals for the parent/transformation products:
--Photolysis experiment: 1, 2, 3, 6, 8.5, 10.75, 23.5, 30.8 and 48 hours after irradiation start.
--Dark experiment: 27 and 48 hours after irradiation start.
--Sensitized photolysis experiment: 0.5, 1, 2, 3, 4, 5, 7, 9 and 24.5 hours after irradiation start.
--Sensitized dark control: 8.45 and 24 hours after irradiation start.
- Sampling methods for the volatile compounds, if any: Traps for volatiles exchanged and analysed at each sample occasion.
- Sampling intervals/times for sterility check: For last samples taken.
- Sample storage conditions before analysis: At 4°C in the dark, with CH3CN content adjusted to 25% v/v.

Buffers:

- pH: 5.36
- Type and final molarity of buffer: 9.6 mM citrate buffer at a concentration of 0.8 mg/L

Light source:

Xenon lamp

Light spectrum: wavelength in nm:

< 290

Relative light intensity:

0.63

Details on light source:

- Emission wavelength spectrum: Wavelengths less than 290 nm cut off
- Filters used and their purpose: Filters cut off wavelength at 290 nm
- Light intensity at sample and area irradiated: 72400 energy units
- Relative light intensity based on intensity of sunlight: 0.63 (based on midday midsummer at 50° N)
- Duration of light/darkness: Constant

Type of sensitiser:

other: triplet sensitiser

Details on sensitiser:

acetone

Concentration of sensitiser:

1 other: % v/v

Details on test conditions:

TEST SYSTEM
- Type, material and volume of test apparatus/vessels: Cylindrical borosilicate glass vessels, of volume 15 mL, with lids.
- Details of traps for volatile, if any: NaOH
- Sterilization: Heat or filtration
- Air flow: 5 mL/min

TEST MEDIUM
- Volume used/treatment: 15 mL
- Identity and concentration of co-solvent: CH3CN at 1% v/v

REPLICATION
- No. of replicates (dark): 1
- No. of replicates (irradiated): 1

OTHER
A senstized control was also run in parallel with 1% acetone

Duration:

48 h

Temp.:

25 °C

Initial conc. measured:

0.8 mg/L

Reference substance:

no

Dark controls:

yes

Computational methods:

- Experimental photolysis reaction rate (direct and/or indirect photolysis): Calculated
- Quantum yield calculations (quantum yield should be expressed as a fraction and not as a percent): Not calculated
- GCSOLAR or ABIWAS calculation of reaction rates at different latitudes, seasons, time of the day, water bodies: Yes (calculation method not specified)
- Half-lives or DT50, DT75, and DT90 values and appropriate associated confidence intervals: Calculated

Parameter:

max lambda

Value:

244 nm

% Degr.:

99.37

Sampling time:

48 h

Test condition:

Non-sensitized

% Degr.:

4.46

Sampling time:

48 h

Test condition:

Non-sensitized, Dark control

% Degr.:

100

Sampling time:

24.5 h

Test condition:

Sensitized

% Degr.:

0

Sampling time:

24.5 h

Test condition:

Sensitized, dark control

DT50:

9.3 h

Test condition:

Non-sensitized

DT50:

4.3 h

Test condition:

Sensitized

Predicted environmental photolytic half-life:

0.62 days at 30°N

Transformation products:

yes

Details on results:

Transformation products detected but could not be identified.

HALF-LIFE
Non-sensitized: 9.3 hours
Sensitized: 4.3 hours

TEST CONDITIONS
- pH, sterility, temperature, and other experimental conditions maintained throughout the study: Yes

Table 1. Measurements of CGA185072 as % of initial level

Irradiation time [hours]	CGA185072 [%]
	Non-sensitized		Sensitized
	Photolysis	Dark Control	Photolysis	Dark Control
0	100		100
0.5			95.86
1	97.08		92.97
2	94.9		83.16
3	92.43		70.56
4			57.32
5			32.06
6	82.5
7			13.72	100
8.5	59.06
9			0
10.75	34.43
23.5	11.92	98.4
24.5			0	100
30.8	5.98
48	0.63	95.54

Validity criteria fulfilled:

not applicable

Conclusions:

Based on the experimental result with artifical light, the half life of the test substance in summer sunlight at 30° N is 0.62 days.

Executive summary:

The photodegradation of the test substance in water was evaluated in a GLP-compliant, guideline test. Based on the experimental result with artifical light, the half life of the test substance in summer sunlight at 30° N is 0.62 days.

Description of key information

The photodegradation of the substance in water was investigated in two studies. The key study determined a half-life of the substance in summer sunlight (assuming 12 hours a day) at 30° N of 0.62 days.

A further study was performed with Acetic acid, 2-[(5-chloro-8-quinolinyl)oxy]- (i.e. the main transformation product in soil and water/sediment systems).

Key value for chemical safety assessment

Half-life in water:

0.62 d

Additional information

The key study (Schäffer, 1991) is a GLP-compliant test conducted according to EPA guideline subdivision N 161-2 (photodegradation studies in water). The photodegradation of the test substance in water was evaluated under artificial light (wavelength <290 nm, relative light intensity based on intensity of sunlight: 0.63 based on midday midsummer at 50° N)) and the half-life of the substance in summer sunlight at 30° N was determined to be 0.62 days (assuming 12 hours of sunlight). A GLP compliant, guideline (UBA Test Guideline "Phototransformation of Chemicals in Water, Part A, Direct Phototransformation", Berlin, FRG, January 1990) supporting study (Phaff, 1996) also found that the photochemical half-life of the substance in surface waters is likely to be short.

A GLP compliant, guideline (UBA Test Guideline "Phototransformation of Chemicals in Water, Part A, Direct Phototransformation", Berlin, FRG, January 1990) supporting study (Abildt, 1995) found that the photochemical half-life of Acetic acid, 2-[(5-chloro-8-quinolinyl)oxy]- in surface waters is likely to be short.