(1E)-1-chloro-3,3,3-trifluoroprop-1-ene

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

14 Jul 2009 to 11 Aug 2009

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

Version / remarks:

1992

Deviations:

not specified

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, predominantly domestic (adaptation not specified)

Details on inoculum:

- Origin: Secondary effluent of city sewage treatment plant, Kurume central sewage treatment center (Kurume, Fukuoka, Japan).
- Sampling date: July 14, 2009.
- Preparation of inoculum: Filtered through a filter paper (No.2); the filtrate was used as inoculum. The inoculum was kept under aerobic conditions until use.

Duration of test (contact time):

ca. 28 d

Initial conc.:

ca. 6.48 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Parameter followed for biodegradation estimation:

test mat. analysis

Details on study design:

PREPARATION OF MINERAL MEDIUM:
According to guideline.

PREPARATION OF TEST SOLUTIONS:
(1) Test solution (water + test item) (n=2): Each bottle was filled with purified water and 0.400 mL of the test substance was added into it by microsyringe so that the concentration of the test item was 6.48 mg/L. The test item solution was prepared by putting approximately 10 mL of the liquid test sample and approximately 60 mL of purified water in a 100-mL conical flask and stirring with a magnetic stirrer for 30 minutes. In order not to decrease the concentration of the test item by volatilization, the test item solution was taken out and put in a 100-mL vacuum sampling bottle. The concentration of the test item of this solution was 1620 mg/L, which was determined by gas chromatography analysis.
(2) Test solution (inoculum + test item) (n=12): Each bottle was filled with the inoculated mineral medium and 0.400 mL of the test item solution was added into it by microsyringe, so that the concentration of the test item was 6.48 mg/L. The test item solution was prepared by putting approximately 10 mL of the liquid test sample and approximately 60 mL of purified water in a 100-mL conical flask and stirring with a magnetic stirrer for 30 minutes. In order not to decrease the concentration of the test item by volatilization, the test item solution was taken out and put in a 100-mL vacuum sampling bottle. The concentration of the test item was 1620 mg/L, which was determined by gas chromatography analysis.
(3) Test solution (inoculum + sodium benzoate) (n=10): Each test bottle was filled with 3.00 mg/L sodium benzoate solution prepared with the inoculated mineral medium.
(4) Test solution (control blank) (n=11): Each test bottle was filled with the inoculated mineral medium.

INSTRUMENTS AND CONDITIONS OF CULTIVATION:
- Incubator (SANYO Electronic Co. Ltd., type MIR-553)
- 100-mL test bottle.
- Cultivation temperature: 20 ± 1 °C
- Cultivation method: each solution was sealed and allowed to stand (in absence of light). The test item is soluble in the test solution.

MEASUREMENT OF DISSOLVED OXYGEN (DO):
Dissolved oxygen of each test solution except the test solutions (water + test item) was measured in accordance with "JIS K 0102-2008 section 32.1", and biochemical oxygen demand (BOD) was calculated from these measurements. Measurements (n=2) were performed at days 0, 7, 14, 21 and 28.

ANALYSIS OF TEST SOLUTION:
After the end of the cultivation, the test item in the test solutions 'water + test item' and the 'inoculum + test item' were determined by gas chromatography in duplicate. The test item in the 'control blank' was determined single sample. The concentrations of the test items in the sample for GC analysis was calculated proportionally by comparing the peak area on the chromatogram of the sample for GC analysis with that on the chromatogram of 0.831 mg/L standard gas. The lowest detectable peak area of the test item was regarded as 1200 µV·sec considering the noise level, which corresponded to the test item concentration of 0.0037 mg/L.

Reference substance:

benzoic acid, sodium salt

Key result

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

28 d

Key result

Parameter:

% degradation (test mat. analysis)

Value:

1

Sampling time:

28 d

Details on results:

- Recovery rates of the test solutions: 'water + test item': 86.1% (average); 'inoculum + test item': 84.2% (average). The average recovery rates were used as a correction factor, for the determination of the test item in the analytical samples.

Results with reference substance:

The reference substance sodium benzoate was degraded 66 - 70% after 14 days.

Percentages biodegradation based on oxygen consumption and test item analysis:

	“inoculum + test item” (mean values)
	7 d	14 d	21 d	28 d
Percentage biodegradation by BOD/ThOD	-1	-1	-4	-2
Percentage biodegradation by test item analysis	-	-	-	1

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

The substance is not readily biodegradable.

Executive summary:

The biodegradability of the substance was determined in a screening study in accordance with OECD TG 301D (closed bottle test) and in compliance with GLP criteria. In this study secondary effluent of city sewage treatment plant was exposed to test substance as follows: (1) Test solution (water + test item) (n=2); (2) Test solution (inoculum + test item (n=12); (3) Test solution (inoculum + sodium benzoate) (n=10) and (4) Test solution (control blank) (n=11). The test substance concentration was 6.48 mg/L. Test flasks were allowed to stand for 28 days at room temperature in the absence of light. After the 28 day exposure period, the cumulative percentages biodegradation were calculated both from the oxygen depletion (BOD/ThOD ratio) and from the decrease of test item concentrations. The observed biodegradation percentages did not exceed 1 in either of the two test methods. Based on these findings the substance is characterised as not readily biodegradable.

Description of key information

The biodegradability of the substance was determined in a screening study in accordance with OECD TG 301D (closed bottle test). In this study, the observed biodegradation percentages did not exceed 1%. Based on these findings the substance is characterised as not readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Type of water:

freshwater

Additional information

The biodegradability of the substance was determined in a screening study in accordance with OECD TG 301D (closed bottle test) and in compliance with GLP criteria (Kurume Laboratory, 2009). In this study secondary effluent of city sewage treatment plant was exposed to test substance as follows: (1) Test solution (water + test item) (n=2); (2) Test solution (inoculum + test item (n=12); (3) Test solution (inoculum + sodium benzoate) (n=10) and (4) Test solution (control blank) (n=11). The test substance concentration was 6.48 mg/L. Test flasks were allowed to stand for 28 days at room temperature in the absence of light. After the 28 day exposure period, the cumulative percentages biodegradation were calculated from both the oxygen depletion (BOD/ThOD ratio) and from the decrease of test item concentrations. The observed biodegradation percentages did not exceed 1% in either of the two test methods. Based on these findings the substance is characterised as not readily biodegradable.