Hex-3-en-1-yl acetate

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:

25 Oct 2016 - 22 Nov 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

Version / remarks:

1992

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Staatliches Gewerbeaufsichtsamt, Hildesheim, Germany

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: Municipal sewage treatment plant, 31137 Hildesheim, Germany
- Storage conditions: under aerobic conditions aerated with CO2-free air
- Storage length: 6 days
- Preparation of inoculum for exposure: was washed twice with chlorine free tap water. After the second washing the settled sludge was resuspended in mineral salts medium and was maintained in an aerobic condition by aeration for 2,5 hours. Thereafter the sludge was homogenized with a blender. After sedimentation the supernatant was decanted and maintained in an aerobic condition.
- Initial cell/biomass concentration: 10 mL/L were used to initiate inoculation (approx. 10^7 - 10^8 CFU/L per test test vessel).

Duration of test (contact time):

28 d

Initial conc.:

21.5 mg/L

Based on:

test mat.

Remarks:

corresponding to a ThOD of 50.1 mg O2/L per vessel

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: Mineral salts medium according to OECD 301 F
- Test temperature: 20.5 - 21.1 °C (measured continuosly throughout the test)
- pH: Inoculum control: 7.66 to 7.74; Functional Control: 7.78 to 7.88; Test Item: 7.64 to 7.67; Toxicity Control: 7.67 to 7.97
- Dispersion treatment: Continuous stirring
- Continuous darkness: yes
- Test volume: 250 mL

TEST SYSTEM
- Culturing apparatus: Brown glass bottles (volume 500 mL),
- Number of culture flasks/concentration: Test Item and Inoculum Control: 2 Replicates; Functional Control and Toxicity Control: 1 Replicate
- Measuring equipment: The oxygen consumption was determined in the incubation vessels by the OxiTop® measuring system at 360 measuring points
- Test performed in closed vessels: The bottles were closed with OxiTop® measuring heads
- Details of trap for CO2 and volatile organics if used: Soda lime

SAMPLING
- Sampling frequency: Continuous measurement (360 measuring points during the 28 days; every 112 minutes one measurement)
- Sampling method: OxiTop® measuring system

CONTROL AND BLANK SYSTEM
- Inoculum control: yes (with 2 replicates)
- Toxicity control: yes
- Functional control: yes

Reference substance:

benzoic acid, sodium salt

Key result

Parameter:

% degradation (O2 consumption)

Value:

90

Sampling time:

28 d

Details on results:

The mean value of biodegradation of the test item reached the 60 % pass level on day 5.
In the toxicity control containing both test and reference item 91% degradation occurred within 14 days.

Results with reference substance:

In order to check the activity of the test system sodium benzoate was used as functional control. The pass level > 60% was reached on day 3. The biodegradation reached a maximum of 92% degradation on day 23.

Validity criteria:

The percentage degradation of the functional control reached the pass level of 60% on day 3. The mean oxygen depletion in the inoculum control was 12.7 mg oxygen/L on day 28. The pH-value of all test replicates was in the range of 6.0 - 8.5 at the end of the test. The difference of extremes of replicate values of removal of the test item at the end of the test was less than 20%. The percentage degradation of the toxicity control reached the pass level of 25% within 2 days.

Table 1: Biodegradation [%] of the Test Item in comparison to the functional control and toxicity control

		Biodegradation [%] Study Day [d]
	Replicate	7	14	21	28
Test Item 21.5 mg/L	1	77	87	86	98
	2	64	69	69	81
	Mean value	71	78	78	90
Functional Control 45 mg/L	83	89	89	91
Toxicity Control 21.5 mg/L Test Item + 45 mg/L Reference Item	80	91	93	98

 

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The substance was found to be readily biodegradable within a 10-day-window. After 28-day exposure 90% degradation was observed. The pass level for ready biodegradability (60% of ThOD) was reached on exposure day 5.

Description of key information

Readily biodegradable (90% within 28 d, OECD 301 F)

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

One experimental study is available investigating the biodegradability of the substance. The study was performed according to OECD 301 F (GLP). Non-adapted, domestic activated sludge from a sewage treatment plant was used as inoculum. The test item was found to be readily biodegradable under the test conditions, with a mean percentage of 90 % degradation at the end of the 28 day exposure period. The pass level for ready biodegradability was reached after 7 days of exposure. Thus, the test substance is considered to be “readily biodegradable” according to the OECD criteria. A toxicity control containing both, reference substance and test substance, did not indicate inhibitory effects to the inoculum (91% degradation after 14 d). All validity criteria of the study were met.