Registration Dossier

Environmental fate & pathways

Biodegradation in water: screening tests

Currently viewing:

Administrative data

Link to relevant study record(s)

Referenceopen allclose all

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
22 Sept - 20 Oct 1992
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: GLP Guideline study with acceptable restrictions: Analytical purity not stated.
Qualifier:
according to
Guideline:
OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Remarks:
The Department of Health of the Government of the United Kingdom
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
- Source of inoculum/activated sludge: Activated sludge was collected from the aeration stage of the Severn Trent Plc sewage treatment plant at Belper, Derbyshire, which treats predominantly domestic sewage. (date of collection: 22 Sept 1992)
- Pretreatment: The activated sludge was homogenized for 10 min. The solids were then removed by centrifuging and the supernatant was taken for testing.
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: Solution 1: FeCl3x6H2O = 0.25 g/L; Solution 2: MgSO4x7H2O = 22.5 g/L; Solution 3: CaCl2 = 27.5 g/L; Solution 4: (NH4)2SO4 = 40 g/L; Solution 5: KH2PO4 = 8.5 g/L, K2HPO4 = 27.75 g/L, Na2HPO4x7H2O = 33.4 g/L, NH4Cl = 1.7 g/L
4 mL Solution 1, 1 mL of each Solution 2, 3 and 4 and 2 mL Solution 5 were added to 1 L of purified water
- Test temperature: 21 ± 1 °C
- pH: day 27: 10 mg/L = 5.4; 20 mg/L = 5.6; control = 5.3; standard = 5.4
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: 5 L glass culture vessel containing 3 L
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: The culture vessels were sealed and CO2-free air bubbled through the solution at a rate of ~ 2 bubbles per second and stirred continuously by magnetic stirrers.
- Measuring equipment: Ionics 555 TOC analyser
- Details of trap for CO2 and volatile organics if used: CO2 was absorbed using 2 500 mL Dreschel bottles filled with 350 mL 0.05 M NaOH

SAMPLING
- Sampling frequency: Samples (2 mL, in triplicate) were taken from the first absorber vessel on days 0, 1, 2, 3, 6, 8, 10, 14, 16, 21, 23, 27 and 28. The second absorber vessel was sampled on days 0 and 28.
- Sampling method: On day 27 the pH of each test vessel was measured and 1 mL of concentrated HCl added to drive of inorganic carbonate. The vessels were aerated overnight and the final samples were taken from both absorber vessels on day 28.

CONTROL AND BLANK SYSTEM
- Inoculum blank: 2 (with and without standard)
Reference substance:
benzoic acid, sodium salt
Remarks:
20 mg/L
Parameter:
% degradation (CO2 evolution)
Value:
74
Sampling time:
28 d
Remarks on result:
other: 10 mg/L test substance concentration
Parameter:
% degradation (CO2 evolution)
Value:
82
Sampling time:
28 d
Remarks on result:
other: 20 mg/L test substance concentration
Details on results:
The test substance reached biodegradation values of 74 (10 mg/L) and 82% (20 mg/L) after 28 days test duration. Furthermore,
degradation over 60% took place within the 10d-window period. Therefore, the test substance can be considered as readily biodegradable.
Results with reference substance:
Sodium acetate reached a biodegradation value of 86% at the end of the test. Besides, degradation over 60% occurred within 14 days (79%).
Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Endpoint:
biodegradation in water: ready biodegradability
Type of information:
(Q)SAR
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
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
Vega version 1.1.4

2. MODEL (incl. version number)
Ready Biodegradability Model (IRFMN) v. 1.0.9

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
See “Test material information”

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
See attached information on the model provided by the developer. Further information on the OECD criteria as outlined by the applicant is provided below under "Any other information of materials and methods incl. tables"

5. APPLICABILITY DOMAIN
See attached information and information as provided in "Any other information on results incl. tables".

6. ADEQUACY OF THE RESULT
See assessment of adequacy as outlined in the "Overall remarks, attachments" section.
Principles of method if other than guideline:
- Software tool(s) used including version: Vega v1.1.4

- Model(s) used: Ready biodegradability model (version 1.0.9)
Full reference and details of the used formulas can be found in:
Meylan W.M., Howard P.H., Boethling R.S. et al. Improved Method for Estimating Bioconcentration / Bioaccumulation Factor from Octanol/Water Partition Coefficient. 1999, Environ. Toxicol. Chem. 18(4): 664-672

- Model description: see field 'Justification for non-standard information', 'Attached justification' and 'any other information on Material and methods'

- Justification of QSAR prediction: see field 'Justification for type of information', 'Attached justification' and/or 'overall remarks'
GLP compliance:
no
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge (adaptation not specified)
Remarks on result:
other: The prediction for the substance component is Readily Biodegradable.

For detailed information on the results please refer to the attached report.

Interpretation of results:
readily biodegradable
Endpoint:
biodegradation in water: ready biodegradability
Type of information:
(Q)SAR
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
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
Vega version 1.1.4

2. MODEL (incl. version number)
Ready Biodegradability Model (IRFMN) v. 1.0.9

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
See “Test material information”

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
See attached information on the model provided by the developer. Further information on the OECD criteria as outlined by the applicant is provided below under "Any other information of materials and methods incl. tables"

5. APPLICABILITY DOMAIN
See attached information and information as provided in "Any other information on results incl. tables".

6. ADEQUACY OF THE RESULT
See assessment of adequacy as outlined in the "Overall remarks, attachments" section.
Principles of method if other than guideline:
- Software tool(s) used including version: Vega v1.1.4

- Model(s) used: Ready biodegradability model (version 1.0.9)
Full reference and details of the used formulas can be found in:
Meylan W.M., Howard P.H., Boethling R.S. et al. Improved Method for Estimating Bioconcentration / Bioaccumulation Factor from Octanol/Water Partition Coefficient. 1999, Environ. Toxicol. Chem. 18(4): 664-672

- Model description: see field 'Justification for non-standard information', 'Attached justification' and 'any other information on Material and methods'

- Justification of QSAR prediction: see field 'Justification for type of information', 'Attached justification' and/or 'overall remarks'
GLP compliance:
no
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge (adaptation not specified)
Remarks on result:
other: The prediction for the substance component is Readily Biodegradable.

For detailed information on the results please refer to the attached report.

Interpretation of results:
readily biodegradable
Endpoint:
biodegradation in water: ready biodegradability
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Remarks:
Summary of available data used for the endpoint assessment of the target substance.
Adequacy of study:
key study
Justification for type of information:
Please refer to the analogue justification attached to chapter 13.
Reason / purpose:
read-across source
Parameter:
% degradation (CO2 evolution)
Value:
74
Sampling time:
28 d
Remarks on result:
other: 10 mg/L test substance concentration
Remarks:
Source, RA-A, CAS 141-17-3
Parameter:
% degradation (CO2 evolution)
Value:
82
Sampling time:
28 d
Remarks on result:
other: 20 mg/L test substance concentration
Remarks:
Source, RA-A, CAS 141-17-3

Description of key information

Readily biodegradable: 74 - 82% in 28 days (OECD 301B); read across;

QSAR prediction: readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

Experimental data on the biodegradability of the target substance Reaction mass of bis[2-[2-(2-butoxyethoxy)ethoxy]ethyl] adipate and [2-[2-(2-butoxyethoxy)ethoxy]ethyl](3,6,9,12-tetraoxahexadecyl)adipate (EC 943-330-9) are not available. The assessment was therefore based on studies conducted with the analogue substance Bis(2-(2-butoxyethoxy)ethyl) adipate (CAS 141-17-3) and on QSAR calculations performed with the main substance components. The read across approach is in accordance with Regulation (EC) No. 1907/2006, Annex XI, 1.5. Please see the analogue justification attached to IUCLID section 13 for a detailed justification.

The biodegradability of the source substance Bis(2-(2-butoxyethoxy)ethyl) adipate (CAS 141-17-3) was tested according to OECD 301B under GLP conditions using non-adapted activated sludge as inoculum. The degradation rate was tested with two different test substance concentrations i.e. 10 mg and 20 mg test material/L. After 28 days a mean degradation rate of 74 % was observed at a test substance concentration of 10 mg/L). The observed degradation rate at 20 mg/L was 82% after 28 days. The 10-day-window was met and the substance was considered as readily biodegradable according to OECD criteria.

The read across approach is supported by QSAR calculations performed with two main substance components of the target substance. Ready biodegradability was predicted for both substance components (VEGA 1.1.4, Ready biodegradability model v1.0.9).

Based on the results for the source substance (in accordance to Regulation (EC) No 1907/2006 Annex XI, 1.5), as well as on the results of the QSAR calculation, Reaction mass of bis[2-[2-(2-butoxyethoxy)ethoxy]ethyl] adipate and [2-[2-(2-butoxyethoxy)ethoxy]ethyl](3,6,9,12-tetraoxahexadecyl)adipate (EC 943-330-9) is considered as readily biodegradable.