Reaction Mass of Cyclohexanepropanol, 2,2,6-trimethyla-propyl-, (alpha.R,1R,6S)- and Cyclohexanepropanol,2,2,6-trimethyl-a-propyl-, [1a(S*),6b]- (9CI)

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:

weight of evidence

Study period:

October 17th 2000 to November 16th 2000

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

Remarks:

This study was performed according to a method very similar to the ISO Guideline 14593 and the OECD Guideline 310 without GLP statement. This study is well documented but a reference material was not tested. The results from the reference test are part of the validity criteria for OECD 310 so the study cannot be considered as valid with or without restrictions in the absence of this information.

Qualifier:

according to guideline

Guideline:

other: The application of dissolved inorganic carbon measurements to the study of aerobic biodegradability, R R Birch and R J Fletcher, Chemosphere, 1991, 23(4), pp507-524.

Deviations:

not specified

Qualifier:

equivalent or similar to guideline

Guideline:

other: ISO Guideline N° 14593: "Water quality - Evaluation of ultimate aerobic biodegradability of organic compounds in aqueous medium - Method by analysis of inorganic carbon in sealed vessels (CO2 headspace test) (adopted 1999)".

Deviations:

yes

Remarks:

non-inclusion of a reference substance, replacing the air in the headspace by pure oxygen to ensure no oxygen transfer limitation and CO2 was measured in the headspace and in the liquid phase without acidification

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 310 (Ready Biodegradability - CO2 in Sealed Vessels (Headspace Test)

Deviations:

not specified

Principles of method if other than guideline:

To avoid distribution during the test (low solubility), the test occurs in 5L bottle.

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

A mixed population of activated sewage sludge micro-organisms was obtained on October 17th, 2000 from the secondary treatment stage of the sewage treatment plant at Aïre (STEP Aïre, ch. de la verseuse, 1219 Aïre (Geneva, Switzerland)), which treats predominantly domestic sewage.
Upon reception, the sample of activated sewage sludge was filtered through filter paper 1 (100 μm). The sample of activated sewage sludge was maintained on continuous aeration upon receipt. A sample of the activated sewage sludge was washed three times by settlement (centrifuge: Heittich rotenta 460 RS) and suspension in culture medium. To remove any excessive amounts of Dissolved Organic Carbon (DOC) that may have been present, the solution was stirred and aerated with pure oxygen at room temperature. Determination of sludge dry weight was performed to inoculate the final solution with 30 mg/L dry weight activated sludge.

Duration of test (contact time):

28 d

Initial conc.:

27.15 mg/L

Based on:

test mat.

Initial conc.:

18.09 mg/L

Based on:

other: C

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

The culture medium used in this study was that recommended in the OECD Guideline N° 310.

On Day 0, the following solutions were inoculated in 5 L glass culture vessels (total volume when full 5.5 L) each containing 2 L of solution:
- A control, in duplicate, consisting of inoculated culture medium, 2 glass culture vessels.
- The test material, in duplicate, in inoculated culture medium, 2 glass culture vessels to give a final concentration of 27.15 mg/L.
All vessels were sealed using Teflon lined silicon septa and incubated at 28°C ± 2°C with constant shaking at approximately 150 rpm (Kuhner ISF-1-W) in diffused light for 28 days.

Carbon dioxide production in the vessels was determined by measuring the increase of IC (Inorganic Carbon) in the headspace and the liquid phase of each vessel. Headspace samples were collected using a gas-tight syringe and needle through the Teflon septum (10 ml) and direct injection on the TOC (Total Organic Carbon) analyser. The sampling of the liquid phase was done through the bottom of the vessel and the samples were analysed using a Shimadzu 5000 TOC analyser. The IC concentration was measured using a non-dispersive infrared detector utilizing CO2-free synthetic air as carrier gas. Each analysis was carried out in triplicate. Calibration of the TOC analyser for IC analysis was done using standard solutions of sodium carbonate and sodium bicarbonate in ultra-pure water.

Reference substance:

not specified

Remarks:

not tested

Preliminary study:

Not applicable

Test performance:

In this study, a standard material was not tested. Therefore, the validity criterion cannot be assessed.

Key result

Parameter:

% degradation (CO2 evolution)

Value:

83

Sampling time:

28 d

Remarks on result:

other: satisfied the 10-day window validation criterion

Details on results:

-1% degradation after 5 and 8 days, 49% degradation after 12 days, 65% degradation after 15 days, 75% degradation after 19 days, 81% degradation after 22 days and 83% degradation after 29 days. See graph in "Illustration".

Results with reference substance:

Not applicable

None

Validity criteria fulfilled:

not specified

Interpretation of results:

readily biodegradable

Conclusions:

The test material attained 83% degradation after 28 days and satisfied the 10-day window validation criterion. Therefore, the test material can be considered to be readily biodegradable under the strict terms and conditions of OECD Guideline.

Executive summary:

This study was performed to investigate the ready biodegradability of the test material when exposed to sewage sludge micro-organisms under aerobic conditions during 28 days. The method followed the protocol as described by Birch and Fletcher (Chemosphere, vol. 23, pp. 507-524, 1991). This method is very similar to the ISO Guideline N° 14593 (CO2 headspace test, adopted 1999) and of the OECD Guideline 310 (adopted March 23rd, 2006).

The activated sewage sludge micro-organisms were exposed to the test material, at a concentration of 18.09 mg C/l, with culture medium in sealed culture vessels in diffused light at 28°C ± 2°C for 28 days. The degradation of the test material was assessed by the determination of carbon dioxide produced on Days 0, 5, 8, 12, 15, 19, 22 and 29.

The test material attained 83% degradation after 28 days and satisfied the 10-day window validation criterion. Therefore the test material can be considered to be readily biodegradable. However, this result can only be considered as a weight of evidence study as no reference substance was tested alongside the study.

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Study period:

Not applicable

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

Remarks:

The value is not an experimental result, however the QSAR model is well documented with regard to validation parameters according to OECD principles. Moreover, the substance is fully characterised and falls within the applicability domain.

Justification for type of information:

1. SOFTWARE
OASIS Catalogic v5.11.15

2. MODEL (incl. version number)
CATALOGIC Kinetic 301F v.11.14 - July, 2014

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
CCCC(O)CCC1C(C)CCCC1(C)C

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

5. APPLICABILITY DOMAIN
See attached QPRF

6. ADEQUACY OF THE RESULT
See attached QPRF

Qualifier:

according to guideline

Guideline:

other: Reach Guidance on QSAR - R.6

Deviations:

no

Principles of method if other than guideline:

QSAR, CATALOGIC Kinetic 301F v.11.14. More details are given in QMRF/QPRF attached to the dossier.

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

Aerobic microorganisms: activated sludge taken from a treatment plant or laboratoryscale unit receiving predominantly domestic sewage. Inoculum may be pre-conditioned to the experimental conditions, but not pre-adapted to the test substance. Pre-conditioning consists of aerating activated sludge in mineral medium or secondary effluent for 5-7 days at the test temperature.

Duration of test (contact time):

28 d

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

not applicable

Preliminary study:

not applicable

Test performance:

BOD is the oxygen used by aerobic microorganisms to mineralize the test substance after a given time (28 days), corrected for oxygen uptake by the blank inoculum control after the same time, and related to the theoretical oxygen demand needed for full mineralization of the substance.

Key result

Parameter:

% degradation (O2 consumption)

Value:

78

Sampling time:

28 d

Remarks on result:

other: Concomitant predictions : Ready degradable; Primary Half Life = < 1 day; Ultimate Half Life = 12.73 days; Start day of Calc. 10 days window =3; BOD calc at 10 days window =0.5253; Classification of Calc. 10 days window =Ready

Details on results:

The chemical fulfils the general properties requirements (log Kow, molecular weight and water solubility). The chemical is in the interpolation structural space and in the metabolic domain.
For additional informations, see the attached QPRF.

Results with reference substance:

not applicable

No additional information

Validity criteria fulfilled:

not applicable

Interpretation of results:

readily biodegradable

Conclusions:

It is expected that the substance is readily biodegradable (78% BOD at 28d).

Executive summary:

The substance ready biodegradation property was investigated using QSAR approach with CATALOGIC Kinetic 301F v.11.14, plug-in from OASIS CATALOGIC v.5.11.15.

According to the results of this prediction (78% BOD at 28d), the substance is expected to be readily biodegradable. This compound fulfills the general properties requirements (in terms of log Kow, molecular weight and water solubility) and is in the interpolation structural space and in the metabolic domain.

Description of key information

Weight of evidence approach, one experimental non-GLP study (2000) and one QSAR data point (CATALOGIC Kintetic 301F v.11.14):

78% degradation after 28 days (QSAR data) to 83% degradation after 28 days (experimental study) meeting the 10 day window;

Readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater

Additional information

To assess the biodegradation potential of the registered substance, a weight of evidence approach was used using an experimental non-GLP study (performed in 2000) and a QSAR data.

The non-GLP experimental study (Firmenich, 2000) was performed on the registered substance to investigate the ready biodegradability of the substance when exposed to sewage sludge micro-organisms under aerobic conditions during 28 days. The method followed the protocol as described by Birch and Fletcher (Chemosphere, vol. 23, pp. 507-524, 1991). This method is very similar to the ISO Guideline N° 14593 (CO2 headspace test, adopted 1999) and of the OECD Guideline 310 (adopted March 23rd, 2006). The activated sewage sludge micro-organisms were exposed to the test substance, at a concentration of 18.09 mg C/l, with culture medium in sealed culture vessels in diffused light at 28°C ± 2°C for 28 days. The degradation of the test substance was assessed by the determination of carbon dioxide produced on Days 0, 5, 8, 12, 15, 19, 22 and 29. The test substance attained 83% degradation after 28 days and satisfied the 10-day window validation criterion. Therefore the registered substance can be considered to be readily biodegradable. However, as no reference susbtance was tested during the study the test can only be used as part of a weight of evidence approach.

The QSAR data was performed to support the experimental result. The substance ready biodegradation property was investigated using CATALOGIC Kinetic 301F v.11.14, plug-in from OASIS CATALOGIC v.5.11.15. The registered substance fulfills the general properties requirements (in terms of log Kow, molecular weight and water solubility) and is in the interpolation structural space and in the metabolic domain. 78% biodegradability (BOD) was observed after 28 days.

Since the outcome of the biodegradability prediction of the registered substance converges with the experimental result, it can be concluded that the substance is readily biodegradable.