Ethyl (E)-4-methylpent-2-enoate

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

The study was conducted between 3 January 2017 and 18 May 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Deviations:

yes

Remarks:

see remark regarding deviation under 'principles of method...' section below:

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)

Deviations:

yes

Remarks:

see remark regarding deviation under 'principles of method...' section below:

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 835.3110 (Ready Biodegradability)

Deviations:

yes

Remarks:

see remark regarding deviation under 'principles of method...' section below:

Principles of method if other than guideline:

Deviations from guidelines.
An apparent decrease in biodegradation on one of the flasks containing reference substance (flask 4) can be attributed to a minor leakage. As the validity criteria are fulfilled on day 28, at the end of the standard test, the validity of the study is not adversely affected.

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Ethyl (E)-4-methylpent-2-enoate

EC Number:

811-774-1

Cas Number:

15790-86-0

Molecular formula:

C8H14O2

IUPAC Name:

Ethyl (E)-4-methylpent-2-enoate

Test material form:

liquid

Specific details on test material used for the study:

Lot No.: SC00019481
Aspect: colourless liquid
Purity: 98.9%

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, industrial (adaptation not specified)

Details on inoculum:

- Source of activated sludge: Domestic sewage works, Bois-de-Bay, Satigny, Switzerland.
- Sludge was collected in the morning, washed three times in the mineral medium (by centrifuging at 1000 g for 10 minutes, discarding the supernatant and resuspending in mineral medium).
- The sludge was kept under aerobic conditions and used the same day.

Duration of test (contact time):

61 d

Initial test substance concentration

Initial conc.:

30 mg/L

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

APPARATUS
- Respirometer: Oxitop Control System.

WATER
- Ultrapure water containing less than 5 ppb total organic carbon was used during the study.

STOCK SOLUTIONS
- Solution A: KH2PO4 8.5 g; K2HPO4 21.75 g, Na2HPO4.2H2O 33.4 g; NH4Cl 0.5 g (dissolved in water and made up to 1 L).
- Solution B: CaCl2 27.5 g (dissolved in water and made up to 1 L).
- Solution C: MgSO4.7H2O 22.5 g (dissolved in water and made up to 1 L).
- Solution D: FeCl3.6H2O 0.25 g; concentrated HCl one drop (dissolved in water and made up to 1 L).

MINERAL MEDIUM
- Solution A (50 mL) and deionised water (2000 mL) were mixed and Solution B (5 mL), Solution C (5 mL) and Solution D (5 mL) added before making up to 5 L with deionised water.

DETERMINATION OF DRY WEIGHT OF SUSPENDED SOLIDS
- Two 50 mL samples of the homogenised sludge were taken and water was evaporated on a steam bath, dried in an oven at 105-110 °C for two hours, and weighing the residue.

FLASK PREPARATION
- Test substance samples (13.10 mg, corresponding to 30 mg/L in 437 mL) were weighed in small aluminium boats and added to the contents of the test flasks of the Oxitop.
- For reference substance samples 43.70 mg (corresponding to 100 mg/L in 437 mL of test medium) were weighed in small aluminium boats and added to the contents of the test flasks of the Oxitop.
- Flasks were filled with 432 mL of mineral medium.
- Suspended sludge diluted to a concentration of 2.62 g/L dry matter was added.
- pH of each flask was not measured but assumed to be the same as the mineral medium.
- Two sodium hydroxide pellets were placed in the quivers on top of the bottle.
- The flasks were then closed tightly with the measuring heads and allowed to equilibrate to the test temperature.
- After temperature equilibration, the controller of the instrument starts the data acquisition (time zero of the experiment).

TEST CONDITIONS
- Temperature (20.6°C - 21.4 °C) and stirring were checked daily.
- Oxygen consumption of each flask was recorded daily.

NOMINAL CONCENTRATIONS
- Test material: 30 mg/L
- Reference substance: 100 mg/L

TOXICITY CONTROL
- An optional toxicity control was not performed. The validity of the study was not adversely affected.

Reference substance

Reference substance:

benzoic acid, sodium salt

Results and discussion

Test performance:

- The activity of the inoculum was verified.
- The repeatability validity criterion (not more than 20% difference between replicates) was fulfilled. Therefore, the test was considered valid.

% Degradation

Key result

Parameter:

% degradation (O2 consumption)

Value:

74

Sampling time:

28 d

BOD5 / COD results

Results with reference substance:

Degradation of reference substance sodium benzoate exceeded 40 % (after 7 days) and 65 % (after 14 days): the activity of the inoculum was thus verified (validity criterion). For details see Appendix 4 of attached study report 16 - E282.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

Ethyl Methyl Pentenoate undergoes 74% biodegradation after 28 days in the test conditions. The 10-day window criterion is also fulfilled. Biodegradation starts on day 3 (18% biodegradation, the 60% pass level is achieved on day 12 (61% biodegradation).

Ethyl Methyl Pentenoate did not inhibit the intrinsic respiration of the inoculum at the test concentration and was therefore considered to be non-toxic to the inoculum at the test concentration.

Thus, Ethyl Methyl Pentenoate should be regarded as readily biodegradable according to this test.

Executive summary:

The Ready Biodegradabilty of Ethyl Methyl Pentenoate was determined by the Manometric Respirometry test.

Ethyl Methyl Pentenoate undergoes 74% biodegradation after 28 days in the test conditions. The 10-day window criterion is also fulfilled. Biodegradation starts on day 3 (18% biodegradation, the 60% pass level is achieved on day 12 (61% biodegradation).

Ethyl Methyl Pentenaote did not inhibit the intrinsic respiration of the inoculum at the test concentration and was therefore considered to be non-toxic to the inoculum at the test concentration.

Thus, Ethyl Methyl Pentenoate should be regarded as readily biodegradable according to this test.