2-Propenoic acid, 2-methyl-, hydroxybutyl ester

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:

03 Jan to 21 Mar, 2007

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: done under OECD method and GLP

Data source

Reference

Reference Type:

other: Unnamed report

Title:

Unnamed

Year:

2007

Report date:

2007

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test)

Version / remarks:

of Commission Directive 92/69/EEC

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

GLP compliance:

yes

Remarks:

Directives 2004/9/EC and 2004/10/EC

Test material

Test material information

Constituent 1

Test material form:

liquid

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

A mixed population of activated sewage sludge micro-organisms obtained on 8th Jan 2007 from the aeration stage of a sewage treatment plant at Loughborough, Leicestershire, UK. Suspended solids determined to be 2.8g/L.

Duration of test (contact time):

29 d

Initial test substance concentration

Initial conc.:

10 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Test temperature: 21°C
- pH: 7.3 - 7.5
- pH adjusted: yes, with HCl


TEST SYSTEM
- Culturing apparatus: 5 litre glass culture vessels each containing 3 litres of solution.
- Number of culture flasks/concentration: 2 test flasks with test substance and inoculum. 2 test flasks with standard(sodium benzoate and inoculum
- Method used to create aerobic conditions: carbon dioxide free air at 40ml/min

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes, inoculated culture medium in duplicate.
- Toxicity control: yes, test material and sodium benzoate. one vessel only.

Reference substance

Reference substance:

other: Sodium benzoate

Results and discussion

Preliminary study:

The test material did not absorb to filter matrices or to activated sewage sludge. The samples taken for DOC analysis therefore be filtered to remove the suspended solids present without the loss of any test material.

% Degradation

% Degradation 1

Parameter:

% degradation (CO2 evolution)

Value:

6

Sampling time:

1 d

% Degradation 2

Parameter:

% degradation (CO2 evolution)

Value:

16

Sampling time:

2 d

% Degradation 3

Parameter:

% degradation (CO2 evolution)

Value:

65

Sampling time:

6 d

% Degradation 4

Parameter:

% degradation (CO2 evolution)

Value:

87

Sampling time:

28 d

% Degradation 5

Parameter:

% degradation (CO2 evolution)

Value:

92

Sampling time:

29 d

Details on results:

Points of degradation plot (test substance): 6 % degradation after 1 d 16 % degradation after 2 d 24 % degradation after 3 d 65% degradation after 6 d 71 % degradation after 8 d 79 % degradation after 10 d 72 % degradation after 14 d 78 % degradation after 16 d 84 % degradation after 20 d 88 % degradation after 22 d 88 % degradation after 24 d 87 % degradation after 27 d 87 % degradation after 28 d and 92% degredation after 29 days.

BOD5 / COD results

Results with reference substance:

Points of degradation plot (sodium benzoate): 20 % degradation after 1 d 43 % degradation after 2 d 41 % degradation after 3 d 42 % degradation after 6 d 54 % degradation after 8 d 61 % degradation after 10 d 63 % degradation after 14 d 66 % degradation after 16 d 81 % degradation after 20 d 84 % degradation after 22 d 84 % degradation after 24 d 82 % degradation after 27 d 88 % degradation after 28 d and 85% degredadation at 29 days.

Any other information on results incl. tables

The toxicity control obtained 89% degredation after 14 days and 97% after 28 days thereby confirming that the test material was not toxic to the sewage treatment organisms used in the test.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The test material attained 87% degradation after 28 days and therefore can be considered to be readily biodegradable under the strict terms and conditions of OECD Guideline No 301B.

Executive summary:

The test material attained 87% degradation after 28 days and satisfies the 10 day window validation criterion, whereby 60% degredation must be obtained within 10 days of the degredation exceeding 10%. The test material can therefore be considered to be readily biodegradable under the strict terms and conditions of OECD Guideline No 301B.