Hexanedioic acid, mixed esters with decanoic acid, heptanoic acid, octanoic acid and pentaerythritol

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:

2017-06-02 - 2017-09-25

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

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)

Test material

Test material information

Constituent 1

Reference substance name:

Hexanedioic acid, mixed esters with decanoic acid, heptanoic acid, octanoic acid and pentaerythritol

EC Number:

268-597-2

EC Name:

Hexanedioic acid, mixed esters with decanoic acid, heptanoic acid, octanoic acid and pentaerythritol

Cas Number:

68130-55-2

Molecular formula:

C36H64O10

IUPAC Name:

6-[3-(decanoyloxy)-2-[(heptanoyloxy)methyl]-2-[(octanoyloxy)methyl]propoxy]-6-oxohexanoic acid

Test material form:

liquid

Specific details on test material used for the study:

Batch number: 026X6
Purity: > 99%/UVCB
Water solubility: insoluble
Realative Density: 0.97 (at 25 °C)
ThOD*: 2.48 mg O2/mg
Appearance: Light yellow liquid

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, non-adapted

Details on inoculum:

Municipal sewage treatment plant, 31137 Hildesheim, Germany.
Activated sludge from the sewage plant at Hildesheim is well suited as it receives predominantly municipal sewage and hardly
any industrial chemical waste.
Receipt: 2017-06-15
Pretreatment:
The activated sludge 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 hours. Thereafter the sludge was homogenized with a blender. After sedimentation the supernatant was decanted
and maintained in an aerobic condition by aeration with CO2-free air for 7 days. 10 ml/L were used to initiate inoculation.
Colony forming units in the test vessels: Approx. 10E7 - 10E8 CFU/l

Duration of test (contact time):

28 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

21 mg/L

Based on:

test mat.

Initial test substance concentration 2

Initial conc.:

52.1 other: mg O2/l

Based on:

ThOD

Parameter followed for biodegradation estimation

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:
Nominal: 20 - 24, ± 1 °C; Actual: 20.0 - 20.6 °c
Occasionally below 20 °C (19.9 °C) for short periods.
- pH: 7.74 - 7.97
- pH adjusted: no
- CEC (meq/100 g):
- Dispersion treatment: Continuous stirring
- Suspended solids concentration:
- Continuous darkness: yes

TEST SYSTEM
- Number of culture flasks/concentration:
• two for the inoculum control (C1, C2)
• one for the functional control (R1)
• two for the test item (P1, P2)
• one for the toxicity control (T1)
Separate replicates of test item and toxicity control were prepared
for measurement of the pH-value at test start:
• one for the test item (PpH)
• one for the toxicity control (TpH)

- Method used to create aerobic conditions: Continuous stirring
- Measuring equipment:
OxiTop® OC110 controller with software Achat OC, WTW
OxiTop® measuring heads, WTW

SAMPLING
- Sampling frequency and Sampling method:
The oxygen consumption was determined in the incubation
vessels by the OxiTop® measuring system at 360 measuring
points (every 112 minutes) during the 28 d incubation period.


CONTROL AND BLANK SYSTEM
- Inoculum control: Test medium without test and / or reference item
- Toxicity control: Test and reference item (in test concentration) in test medium

Reference substance

Reference substance:

benzoic acid, sodium salt

Results and discussion

% Degradation

Key result

Parameter:

% degradation (O2 consumption)

Value:

53

Sampling time:

28 d

BOD5 / COD results

Results with reference substance:

The pass level for ready biodegradation (~ 60% degradation) was reached within 3 days. The
validity criterion that the degradation should be~ 60% after 14 d was fulfilled.
Stages of Biodegradation: The adaptation phase changed to degradation phase within 2 days
(degradation> 10%) and the biodegradation came to a maximum of 97% on day 28.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

After a test period of 28 days, the test item is classified as not readily biodegradable within the 28 day period of the study.

Executive summary:

The test item reached the 10% level (beginning of biodegradation) on day 3.

The 60% pass level was not reached within the 28 day period of the study. The mean biodegradation on day 28 was 53%.

After a test period of 28 days, the test item is classified as not readily biodegradable within the 28 day period of the study.