3-(C6-16, (even numbered) and C16 unsaturated alkyl)-4-(C7-17 (odd numbered) and C17 unsaturated alkylidene)-oxetan-2-one

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:

20 February - 20 March 2008

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study has been performed according to OECD and EC guidelines and according to GLP principles.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2008

Report date:

2008

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

ISO DIS 9439 (Ultimate Aerobic Biodegradability - Method by Analysis of Released Carbon Dioxide)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

3-(C6-16, (even numbered) and C16 unsaturated alkyl)-4-(C7-17 (odd numbered) and C17 unsaturated alkylidene)-oxetan-2-one

EC Number:

700-132-5

Cas Number:

863782-35-8

Molecular formula:

See remarks.

IUPAC Name:

3-(C6-16, (even numbered) and C16 unsaturated alkyl)-4-(C7-17 (odd numbered) and C17 unsaturated alkylidene)-oxetan-2-one

Details on test material:

- Name of test material (as cited in study report): Aquapel® 203
- Substance type: yellow fatty liquid
- Physical state: liquid
- Analytical purity: 89.9%
- Lot/batch No.: G12FY067
- Expiration date of the lot/batch: 12 June 2008
- Stability under storage conditions: stable
- Storage condition of test material: at room temperature in the dark

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): The source of test organisms was activated sludge freshly obtained from a municipal sewage treatment plant: 'Waterschap de Maaskant', 's-Hertogenbosch, The Netherlands, receiving predominantly domestic sewage.
- Storage conditions: The freshly obtained sludge was kept under continuous aeration until further treatment.
- Storage length:
- Preparation of inoculum for exposure:
- Pretreatment: Before use, the sludge was allowed to settle (83 minutes) and the liquid was decanted for use as inoculum at the amount of 10 ml/l of mineral medium
- Initial cell/biomass concentration: The concentration of suspended solids was 4.4 g/l in the concentrated sludge (information obtained from the municipal sewage treatment plant).

Duration of test (contact time):

28 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

12 mg/L

Based on:

other: TOC

Initial test substance concentration 2

Initial conc.:

31 other: mg/2L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: 1 litre mineral medium contains: 10 ml of solution (A), 1 ml of solutions (B) to (D) and Milli-RO water.
A) 8.50 g KH2PO4, 21.75 g K2HPO4, 67.20 g Na2HPO4.12H2O, 0.50 g NH4Cl dissolved in Milli-Q water and made up to 1 litre, pH 7.4 ± 0.2
B) 22.50 g MgSO4.7H2O dissolved in Milli-Q water and made up to 1 litre.
C) 36.40 g CaCl2.2H2O dissolved in Milli-Q water and made up to 1 litre.
D) 0.25 g FeCl3.6H2O dissolved in Milli-Q water and made up to 1 litre.
- Test temperature: 21.3 - 22.9°C.
- pH: 7.5 - 7.8
- pH adjusted: yes
- Suspended solids concentration: 4.4 g/l in the concentrated sludge
- Continuous darkness: yes
- Other:


TEST SYSTEM
- Culturing apparatus: 2 litre all-glass brown coloured bottles.
- Number of culture flasks/concentration:
Test suspension: containing test substance and inoculum (2 bottles).
Inoculum blank: containing only inoculum (2 bottles)
Positive control: containing reference substance and inoculum (1 bottle).
Toxicity control: containing test substance, reference substance and inoculum (1 bottle).
The test substance and positive control were added to the bottles containing the microbial organisms and mineral components (ca. 80% of total volume). The volumes of suspensions were made up to 2 litres with Milli-RO water, resulting in the mineral medium described before.
- Method used to create aerobic conditions: During the test period the test media were aerated and stirred continuously.
- Measuring equipment: The amount of CO2 produced was determined by titrating the remaining Ba(OH)2 with 0.05 M standardized HCl (1:20 dilution from 1 M HCl (Titrisol® ampul), Merck, Darmstadt, Germany).
- Details of trap for CO2 and volatile organics if used:
Three CO2-absorbers (bottles filled with 100 ml 0.0125 M Ba(OH)2 were connected in series to the exit air line of each test bottle. Synthetic air (CO2 < 1 ppm): A mixture of oxygen (21%) and nitrogen (79%) was passed through a bottle, containing 0.5 - 1 litre 0.0125 M Ba(OH)2 solution to trap CO2 which might be present in small amounts. The synthetic air was sparged through the scrubbing solutions at a rate of approximately 1-2 bubbles per second (ca. 30-100 ml/min).
The CO2 produced in each test bottle reacted with the barium hydroxide in the gas scrubbing bottle and precipitated out as barium carbonate.



SAMPLING
- Sampling frequency: Titrations were made every second or third day during the first 10 days, and thereafter at least every fifth day until the 28th day. Each time the CO2-absorber nearest to the test bottle was removed for titration; each of the remaining two absorbers was moved one position in the direction of the test bottle. A new CO2-absorber was placed at the far end of the series. Phenolphthalein (1% solution in ethanol, Merck, Darmstadt, Germany) was used as pH-indicator.
On the 28th day, the pH of the test suspensions was measured and 1 ml of concentrated HCl (37%, Merck, Darmstadt, Germany) was added to each bottle. The bottles were aerated overnight to drive off CO2 present in the test suspension. The final titration was made on day 29.


CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Abiotic sterile control: no
- Toxicity control: reference substance was Sodium acetate



STATISTICAL METHODS: none

Reference substance

Reference substance:

acetic acid, sodium salt

Results and discussion

Preliminary study:

Because the theoretical calculation of the CO2 production was not possible a sample of Aquapel® 203 was taken for TOC analysis.
The TOC content of Aquapel® 203 was determined to be 78%. Based on the TOC content the ThCO2 of Aquapel® 203 was calculated to be 2.87 mg CO2/mg.
The ThCO2 of Sodium Acetate was calculated to be 1.07 mg CO2/mg.

% Degradation

Parameter:

% degradation (CO2 evolution)

Value:

54

Sampling time:

28 d

Details on results:

The relative degradation values calculated from the measurements performed during the test period revealed 54 and 52% degradation of Aquapel® 203, for the duplicate bottles tested. Thus, the criterion for ready biodegradability (at least 60% biodegradation within a 10-day window) was not met.

BOD5 / COD results

Results with reference substance:

In the toxicity control more than 25% degradation occurred within 14 days (48%, based on ThCO2). Therefore, the test substance was assumed not to inhibit microbial activity.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

other: not readily biodegradable

Conclusions:

Aquapel® 203 was not readily biodegradable under the conditions of the modified Sturm test presently performed.