N,N'-hexane-1,6-diylbis[3-(3,5-di-tert-butyl-4-hydroxyphenylpropionamide]

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1988-09-22 to 1988-11-01

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Non-GLP guideline study

Qualifier:

according to guideline

Guideline:

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

Deviations:

yes

Remarks:

see principles of method other than guideline field.

Principles of method if other than guideline:

The volume of the test solution was reduced from 3.0 L to 1.5 L. The CO2 formed by biodegradation was absorbed with NaOH and determined on a carbon analyzer. Due to the poor solubility of the test substance in water, an emulsifier was used to achieve a better distribution in the medium. The test, substance was added to the medium, homogenized with Nonylphenol 10E05P0. The CO2 production of the blank was 29.3 mg/L medium.

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: Bacteria collected from activated sludge of the sewage treatment plant of CH - 4153 Reinach
- Preparation of inoculum for exposure: The preparation was carried out according to the method described in the guideline.

Duration of test (contact time):

28 d

Initial conc.:

10 mg/L

Based on:

test mat.

Initial conc.:

20 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
1200 mL of the mineral solution with the inoculum were aerated for 24 hours in the test vessel. In 300 mL mineral solution 0.5 ml Nonylphenol 10E05P0 (solution of 31.2 mg in 100 mL bidist. water) and 15 rsp. 30 mg of test substance were added and homogenized. This solution was given to the test vessel which was immediately connected to the CO2 traps.
- Solubilising agent (type and concentration if used): Nonylphenol 10E05P0
- Test temperature: 22 ± 2°C

TEST SYSTEM
- Culturing apparatus: 2 Liter flasks equipped with gas inlet and magnetic stirrer.
- Number of culture flasks/concentration: 1
- Method used to create aerobic conditions: Approx. 25 mL/min free of carbon dioxide.
- Measuring equipment: carbon analyzer
- Details of trap for CO2 and volatile organics if used: Determination of the initial CO2 of the 0.05 N sodium hydroxide and the CO2 absorbed in the absorbers filled with 200 ml 0.05 N sodium hydroxide on the days 5, 11, 18, 22, 27 and 28

SAMPLING
- Sampling frequency: 5, 11, 18, 22, 27 and 28 days

CALCULATIONS:
- The biodegradation was calculated on the basis of the theoretical carbon content of the test substance and the cumulative quantities of carbon dioxide determined on the days of measurements. For the calculation the formula given in the guideline was used. For the blank values, the blank with the
vehicle was used.

ThOC:
- 10 mg test substance are equivalent to 7.543 mg organic carbon. This calculation is based on the chemical formula: C40H64N2O4

Reference substance:

aniline

Remarks:

20 mg/L

Parameter:

% degradation (CO2 evolution)

Value:

5

Sampling time:

28 d

Remarks on result:

other: Dose: 10 mg/L

Parameter:

% degradation (CO2 evolution)

Value:

3

Sampling time:

28 d

Remarks on result:

other: Dose: 20 mg/L

Details on results:

The biodegradation calculated as percentage of measured amount of carbondioxide over the theory was:
10 mg test substance/L = 5% in 28 days.
20 mg test substance/L = 3% in 28 days.

Results with reference substance:

20 mg/L = 94.4% in 28 days.

Executive summary:

The ready biodegradability of the test item was assessed over a 28 day period by the modified Sturm test. The nominal test concentrations were 10 and 20 mg a.s./L. The test material attained up to 5 and 3 % biodegradation after 28 days whereas the positive control substance (Aniline) was 94.4 % degraded 28 days. These results indicate that the test item cannot be classified readily biodegradable under conditions of the test.

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

(Q)SAR

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

1. SOFTWARE
OASIS Catalogic v5.11.19

2. MODEL (incl. version number)
CATALOGIC 301C v.09.13

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
See section 'Test Material'.

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
See attached QMRF.

5. APPLICABILITY DOMAIN
See attached QPRF.

6. ADEQUACY OF THE RESULT
- The model is scientifically valid (see attached QMRF).
- The model estimates the biodegradability of a substance and identifies its degradation betabolites. Screening information on the ready biodegradability is required for substances manufactured or imported in quantities of 1 t/y or more. Depending on the results, further information may be required for substances manufactured or imported in quantities of 100 t/y or more (simulation testing on ultimate degradation in surface water/soil/sediment). Column 2 of REACH Annex VII provides exemptions for conducting the study. It does not need to be conducted if the substance is inorganic. According to column 2 of REACH Annex IX, testing is not required if the substance is highly insoluble in water, or the substance is readily biodegradable.
- See attached QPRF for reliability assessment.

Principles of method if other than guideline:

Estimation of ready biodegradation in water using CATALOGIC v5.11.19 BOD 28 days MITI (OECD 301C) v09.13

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

other: Model calculation

Duration of test (contact time):

28 d

Parameter:

% degradation (O2 consumption)

Value:

6

Sampling time:

28 d

Remarks on result:

not readily biodegradable based on QSAR/QSPR prediction

- Concomitant predictions :

Not readily biodegradable

Primary Half Life = 10.10 days

Ultimate Half Life = 9 months 24 days

- Predicted value (model result): O2 -consumption (BOD) = 0.06 ± 9.13E-3

Main metabolite: 3-(3,5-ditert-butyl-4-hydroxy-phenyl)propanoic acid

Interpretation of results:

not readily biodegradable

Remarks:

parent substance

Conclusions:

The substance is not readily biodegradable.

Description of key information

Not readily biodegradable (according to OECD criteria).

Additional information

The ready biodegradability of the test item was assessed over a 28 day period by the modified Sturm test (OECD 301B). The nominal test concentrations were 10 and 20 mg a.s./L. The test material attained up to 5 and 3 % biodegradation after 28 days whereas the positive control substance (Aniline) was 94.4 % degraded 28 days. These results indicate that the test item cannot be classified readily biodegradable under conditions of the test.

Additional QSAR calculations with Catalogic v5.11.19, Catalogic 301C v09.13 revealed a degradation of 6% after 28d. The main metabolite was 3-(3,5-ditert-butyl-4-hydroxy-phenyl)propanoic acid.

The test substance was found to be poorly biodegradable in an OECD 301B study. It is assumed that the results of further simulation studies would not reveal any different findings. Therefore, further simulation studies in water/sediment and soil are not provided.