4'-trans-propyl-1,1'-bicyclohexyl-4-trans-carboxaldehyde

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

3 APR 2007 - 31 MAY 2007

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

Version / remarks:

OECD Guideline for Testing of Chemicals No. 301 F: "Ready Biodegradability: Manometric Respirometry Test", adopted July 17, 1992

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)

Version / remarks:

Commission Directive 92/69/EEC, Method C.4-D of July 31, 1992: Manometric Respirometry Test (EEC Publication No. L 383 A, December 1992)

GLP compliance:

yes (incl. QA statement)

Remarks:

Hess. Ministerium für Umwelt, ländlichen Raum und Verbraucherschutz, Mainzer Straße 80, 65189 Wiesbaden (22 Nov 2005)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Aerobic activated sludge, microorganisms from a domestic waste water treatment plant was supplied by the sewage plant Rossdorf, Germany.
- Preparation of inoculum for exposure: The activated sludge used for this study was washed by centrifugation and the supernatant liquid phase was decanted. The solid material was re-suspended in tap water and again centrifuged. This procedure was repeated twice. An aliquot of the final sludge suspension was weighed, dried and the ratio of wet sludge to its dry weight was determined. Based on this ratio, calculated aliquots of washed sludge suspension, corresponding to 1.5 g dry material per litre were mixed with test water and then aerated until use. The washed activated sludge was pre-incubated for two days under aeration.
- Concentration of sludge: Stock suspension of 1.5 g/L on dry matter base (final concentration: 30 mg/L).

Duration of test (contact time):

28 d

Initial conc.:

103 mg/L

Based on:

test mat.

Remarks:

The concentration based on test material is corresponding to about 315 mg/L based on ThOD of 3.046 mg oxygen per mg test item.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: Reconstituted test water:
In deionised water analytical grade salts were added to prepare the following stock solutions:
a) 8.5 g KH2PO4, 21.75 g K2HPO4, 33.4 g Na2HPO4 x 2 H2O, 0.5 g NH4Cl filled up with deionised water to 1000 mL volume
b) 22.5 g MgSO4 x 7H2O filled up with deionised water to 1000 mL volume
c) 36.4 g CaCl2 x 2H2O filled up with deionised water to 1000 mL volume
d) 0.25 g FeCI3 x 6H2O filled up with deionised water to 1000 mL volume
In order to avoid preparation of the stock solution d) immediately before use, one drop of concentrated HCl per litre was added.
10 mL of stock solution a) and 1 mL of the stock solutions b) - d) were combined and filled to a final volume of 1000 mL with deionised water.
- Test temperature: 22 °C
- pH:
7.6 (measured at the start of the test)
7.5 - 7.8 (measured at the end of the test)
- pH adjusted: no
- Aeration of dilution water: not specified
- Suspended solids concentration: 1.5 g dry material per litre
- Continuous darkness: yes
- Other: The closed test flasks were incubated in a climatic chamber under continuous stirring.

TEST SYSTEM
- Culturing apparatus: Manometric Test System with test flasks containing a volume of 500 mL.
- Number of culture flasks/concentration:
Test item group: 2
Incoculum control: 2
Procedure control: 1
Abiotic control: 1
Toxicity control: 1
- Measuring equipment: BSB/BOD-Sensor-System, Aqualytic, 63231 Neu Isenburg, Germany

SAMPLING
- Sampling frequency: The change of pressure in the test flasks was measured by means of a manometric method (BSB/BOD-Sensor-System, Aqualytic, 63231 Neu Isenburg, Germany) each day.

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Abiotic sterile control: yes
- Toxicity control: yes
- Other: Procedure control: yes

Reference substance:

benzoic acid, sodium salt

Parameter:

% degradation (O2 consumption)

Value:

6

Sampling time:

28 d

Details on results:

- Percentage Biodegradation Test Item:
Under the test conditions the biodegradation of the test item reached 6 % after 28 days of incubation.
Conclusion: The percentage biodegradation did not exceed 60 % within the 10-day window and after 28 days of incubation. The test item is considered not to be readily biodegradable.
- Percentage Biodegradation Reference Item:
The reference item sodium benzoate was sufficiently degraded to 70 % after 4 days and to 92 % after 28 days of incubation.
Conclusion: The percentage biodegradation of the reference item confirms the suitability of the used activated sludge inoculum.
- Percentage Biodegradation Toxicity Control:
In the toxicity control containing both, the test item and the reference item 32 % biodegradation was noted within 14 days and 44 % biodegradation was determined after 28 days of incubation.
Conclusion: According to the test guidelines the test item can be assumed to be not inhibitory on the activated sludge microorganisms because degradation was >25 % within 14 days.
- Oxygen Demand Abiotic Control:
The oxygen demand in the abiotic control was zero. No correction of the test item degradation rates had to be done.

Results with reference substance:

The reference item sodium benzoate was sufficiently degraded to 70 % after 4 days and to 92 % after 28 days of incubation. The percentage biodegradation of the reference item confirms the suitability of the used activated sludge inoculum.

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

The study was conducted under GLP according to OECD 301 F and the Commission Regulation 440/2008/EC, C.4-D on the registered substance itself. The method is to be considered scientifically reasonable and suitable for the test item with detailed documentation. Hence, the results can be considered as reliable to assess the ready biodegradability of the test substance. Based on the obtained results the degradation rate of the test substance did not reach 60% within the 10-day window or after 28 days. It was determined to be 6 % after 28 days. Hence, the test substance is considered to be not readily biodegradable.

Executive summary:

The study was conducted under GLP according to OECD Guideline 301 F and EU Method C.4 -D at a nominal concentration of 103 mg test substance/L for 28 days. The method is to be considered scientifically reasonable and suitable for the test item with detailed documentation. Hence, the results can be considered as reliable to assess the ready biodegradability of the test substance. Sodium benzoate served as reference item for the positive control.

The criterion for ready biodegradability under the conditions of a manometric respirometry test is the 10-day window, describing the period between reaching at least 10 % degradation and 60 % degradation. This period should not exceed 10 days.

The degradation rate of the test substance did not reach 60 % within the 10-day window or after 28 days. It was determined to be 6 % after 28 days. Therefore, the test substance is considered to be not readily biodegradable.

Description of key information

Key, 28 d, OECD 301F, GLP: not ready biodegradable

Key value for chemical safety assessment

Biodegradation in water:

not biodegradable

Type of water:

freshwater

Additional information

The study was conducted under GLP according to OECD Guideline 301 F and EU Method C.4 -D at a nominal concentration of 103 mg test substance/L for 28 days. The method is to be considered scientifically reasonable and suitable for the test item with detailed documentation. Hence, the results can be considered as reliable to assess the ready biodegradability of the test substance. Sodium benzoate served as reference item for the positive control.

The criterion for ready biodegradability under the conditions of a manometric respirometry test is the 10-day window, describing the period between reaching at least 10 % degradation and 60 % degradation. This period should not exceed 10 days.

The degradation rate of the test substance did not reach 60 % within the 10-day window or after 28 days. It was determined to be 6 % after 28 days.

Therefore, the test substance is considered to be not readily biodegradable.