Ethylenebis(oxyethylene) bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate]

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:

1984-02-15 to 1984-03-21

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Study design appears to follow OECD guideline 301B (1992) with deviations. Contains sufficient detail to suggest GLP-like characteristics. The volume of the test solution was reduced from 3.0 liter to 1.5 liter. The test substance was not dissolved in the test medium.

Qualifier:

according to guideline

Guideline:

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

Deviations:

yes

Remarks:

no blank. The volume of the test solution was reduced from 3.0 liter to 1.5 liter. The test substance was not dissolved in the test medium.

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

Bacteria collected from activated sludge of the sewage treatment plant of CH-4310 Rheinfelden on 14/02/1984. 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
- Composition of medium: The test medium was prepared according to the method described in the guideline
- Test temperature: 22 ± 2°C
- Aeration: Approx. 50 ml/min free of carbon dioxide.

TEST SYSTEM
- Number of culture flasks/concentration: 2 liters flasks equipped with gas inlet and magnetic stirrer. 1 vessel per test substance concentration (10 and 20 mg test substance/L and 1 vessel for the reference substance for a total of 3 vessels.
- Details of trap for CO2 and volatile organics if used: Titration of the carbondioxide, absorbed in the absorbers filled with 0.025 N Barium hydroxide.
- Method used to create aerobic conditions: aeration and magnetic stirrer

SAMPLING
- Sampling frequency: on the days 2/6/9/14/19/23/27 and 28

CONTROL AND BLANK SYSTEM
- Toxicity control: yes

Reference substance:

aniline

Remarks:

20 mg/L

Test performance:

The test substance was not dissolved in the test medium. This did not affect the validity of the test.

Parameter:

% degradation (CO2 evolution)

Value:

8

Sampling time:

28 d

Remarks on result:

other: 10 mg test substance /L

Parameter:

% degradation (CO2 evolution)

Value:

3

Sampling time:

28 d

Remarks on result:

other: 20 mg test substance /L

Details on results:

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 calculations the formula given in the guideline was used.

Results with reference substance:

The aniline biodegradation was 96% in 28 days (tested at a concentration of 20mg/L).

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 v5.14.1.5

2. MODEL (incl. version number)
CATALOGIC 301C v.11.16

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 v5.14.1.5 BOD 28 days MITI (OECD 301C) v11.16

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:

14

Sampling time:

28 d

Remarks on result:

not readily biodegradable based on QSAR/QSPR prediction

- Concomitant predictions :

Not readily biodegradable

Primary Half Life = 4.20 days

Ultimate Half Life = 4 months 11 days

 

- Predicted value (model result): O2 -consumption (BOD) = 0.14 ± 0.0141

Metabolites

Without the parent substance 49 metabolites were identified by the QSAR model (see table in section overall remarks). 20 of them occured in higher quatities above 0.1 % (see attached QPRF). Regarding the PBT assessment metabolites with quantities above 0.1 % and a log Kow above 4 were further assessed for their bioaccumulation potential. These criteria apply to 2 metabolites (#9 and #9), while # is predicted to be the main metabolite:

#	Cas#	Chem. Name	Smiles	Quantity [mol/mol parent]	Quantity [%]	log Kow	Molecular weight Da	Water solubility (FR) mg/L
1.31	N/A		Cc1cc(CCC(=O)OCCOCCOCCOC(=O)CCc2cc(C(C)(C)C)c(O)c(C(O)=O)c2)cc(C(C)(C)C)c1O	0.003834	0.3834	8.3916	616.7092	0.00073
1.1	36443-68-2		Cc1cc(CCC(=O)OCCOCCOCCOC(=O)CCc2cc(C)c(O)c(C(C)(C)C)c2)cc(C(C)(C)C)c1O	0.009831	0.9831	8.207	586.7271	0.003837
1.9	N/A		Cc1cc(CCC(O)=O)cc(C(C)(C)C)c1O	1.545	154.5	4.2623	236.295	493.4767

 

Interpretation of results:

not readily biodegradable

Remarks:

parent substance

Conclusions:

The substance is not readily biodegradable. The main metabolite is 3-(3-tert-butyl-4-hydroxy-5-methyl-phenyl)propanoic acid.

Description of key information

Not readily biodegradable (by OECD criteria).

Additional information

In Article 13 of Regulation (EC) No 1907/2006, it is laid down that information on intrinsic properties of substances may be generated by means other than tests, provided that the conditions set out in Annex XI (of the same Regulation) are met. Furthermore, according to Article 25 of the same Regulation testing on vertebrate animals shall be undertaken only as a last resort.

According to Annex XI of Regulation (EC) No 1907/2006 (Q)SAR results can be used if (1) the scientific validity of the (Q)SAR model has been established, (2) the substance falls within the applicability domain of the (Q)SAR model, (3) the results are adequate for the purpose of classification and labeling and/or risk assessment and (4) adequate and reliable documentation of the applied method is provided.

For the assessment of CAS 36443-68-2 (Q)SAR results were used for biodegradation. The criteria listed in Annex XI of Regulation (EC) No 1907/2006 are considered to be adequately fulfilled and therefore the endpoint(s) sufficiently covered and suitable for risk assessment.

 

Therefore, further experimental studies on biodegradation are not provided.

 

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 8 and 3 % biodegradation after 28 days whereas the positive control substance (Aniline) was 96 % 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 14% after 28d. 50 metabolites were predicted and for 20 of them a quantity greater than 0.1 % was predicted. Due to low log Kow values (<4) 18 of them were not further assessed regarding their bioaccumulation potential. 2 metabolites (#9 and #31) were further assessed for their bioaccumulation potential (see 5.3.1). The main metabolite was3-(3-tert-butyl-4-hydroxy-5-methyl-phenyl)propanoic acid (#9).

A simulation study in water and sediment is not regarded as valid as it could not be clarified if the substance degraded or merely bound to the sludge.

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.