N,N'-propane-1,3-diylbis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide]

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Justification for type of information:

Additional documentation, provided within the IUCLID Assessment Reports (Section 13), supports the read-across approach.

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

according to guideline

Guideline:

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

Deviations:

yes

Remarks:

Refer to Any other information on materials and methods incl. tables for additional information.

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

other: Activated sludge of the sewage treatment plant

Details on inoculum:

- Source of inoculum/activated sludge: CH - 4153 Reinach

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
- Test temperature: 22 ± 2°C
- Air: Approximately 25 mL/min free of carbon dioxide

TEST SYSTEM
- Culturing apparatus: 2 litre flasks equipped with gas inlet and magnetic stirrer
- Number of culture flasks/concentration: 2
- Details of trap for CO2: The CO2 formed was absorbed with NaOH and determined on a carbon analyser

CONTROL AND BLANK SYSTEM
- Blank + vehicle: Water as specified in the guideline containing 0.5 mL of the Nonylphenol solution
- Blank: Water as specified in the guideline
- Toxicity control: Aniline (20 mg/L)

Reference substance:

aniline

Key result

Parameter:

% degradation (CO2 evolution)

Value:

5

Sampling time:

28 d

Remarks on result:

other: 10 mg/L test substance

Key result

Parameter:

% degradation (CO2 evolution)

Value:

3

Sampling time:

28 d

Remarks on result:

other: 20 mg/L test substance

Results with reference substance:

Biodegradation was 94.4% in 28 days at 20 mg/L.

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

10 mg/L: 5% in 28 days
20 mg/L: 3% in 28 days

Executive summary:

The test substance was determined for the biodegradability by measurement of the carbon dioxide formation following OECD guidelines 301 B. The test system was the bacteria collected from a sewage treatment plant. 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 days 5, 11, 18, 22, 27, and 28 was measured. 20 mg/L of aniline was used as the reference standard.

The biodegradation calculated as percentage of measured amount of carbon dioxide over the theory was 5 and 3% at 28 days at 10 and 20 mg/L, respectively. The test substance was not biodegradable in this test.

Description of key information

No biodegradation study with the test substance is available. A study in accordance with OECD Guideline 301B with N,N'-hexane-1,6-diylbis[3-(3,5-di-tert-butyl-4-hydroxyphenylpropionamide] was used as read across to fulfill the data gap for the test substance. The underlying hypothesis supporting read-across from the source (N,N'-hexane-1,6-diylbis[3-(3,5-di-tert-butyl-4-hydroxyphenylpropionamide]; CAS 23128-74-7) to the target (N,N'-propane-1,3-diylbis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide]; CAS 69851-61-2) includes the following: (1) Structural similarity, (2) Source and target are expected to hydrolyse in a similar fashion, (3) Source and target have similar predicted metabolism, (4) Source and target have similar physicochemical properties, (5) Source and target have similar calculated chemical descriptors, and (6) Source and target have similar predictions for the endpoints of concern. Additional documentation, provided within the IUCLID Assessment Reports section, supports the read-across approach.

The biodegradation calculated as percentage of measured amount of carbon dioxide over the theory was 5 and 3% in 28 days at 10 and 20 mg test substance/L, respectively.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed