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Environmental fate & pathways

Biodegradation in water: screening tests

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Endpoint:
biodegradation in water: ready biodegradability
Remarks:
301C
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:
QSAR prediction from a well-known and acknowledged tool. See below under ''attached background material section' for methodology and QPRF.
Qualifier:
according to guideline
Guideline:
other: REACH guidance on QSARs: Chapter R.6. QSARs and grouping of chemicals
Principles of method if other than guideline:
Since the test substance is a UVCB with similar constituents (varying mainly in the number of acrylates Pentaerythritol backbone as well as adduct formation), the ultimate half-life values were predicted for the individual constituents of boundary composition.
Specific details on test material used for the study:
Input data for the model: SMILES of the individual constituents:

1) CAS Nr.: 3524-68-3; SMILES: C=CC(=O)OCC(CO)(COC(=O)C=C)COC(=O)C=C
2) CAS Nr.: 4986-89-4; SMILES: C=CC(=O)OCC(COC(=O)C=C)(COC(=O)C=C)COC(=O)C=C
3) CAS Nr.: 1174682-57-5; SMILES: C=CC(=O)OCC(COCCC(=O)OCC(COC(=O)C=C)(COC(=O)C=C)COC(=O)C=C)(COC(=O)C=C)COC(=O)C=C
4) CAS Nr.: 1240563-05-9; SMILES: O=C(OCC(COC(C=C)=O)(COCCC(=O)OCC(COC(=O)C=C)(COC(C=C)=O)CO)COC(=O)C=C)C=C
5) CAS Nr.: 1240564-04-8; SMILES: C=CC(=O)OCC(CO)(COCCC(=O)OCC(CO)(COC(=O)C=C)COC(=O)C=C)COC(=O)C=C
6) CAS Nr.: 1240564-03-7; SMILES: C=CC(=O)OCCC(=O)OCC(COC(=O)C=C)(COC(=O)C=C)COC(=O)C=C


*All constituents present at >9.5% have been taken into account for QSAR modelling.
Key result
Parameter:
half-life in days (QSAR/QSPR)
Remarks:
Ultimate half-life (weighted average)
Value:
> 26.8 - < 62
Remarks on result:
other: according to CATALOGIC 301C v.11.15
Details on results:
For detailed results and domain evaluation, kindly refer the attached QPRF in attached background material section of IUCLID.

Results:

Constituent CAS Nr.

 

Boundary composition (% w/w)

 

CATALOGIC Kinetic 301C v.11.15 - ultimate half-life

 

Domain evaluation

 

3524-68-3

3 – 50 %

1m 4d

In domain

4986-89-4

10 - 60

29.06 days

In domain

1174682-57-5

5 -35

1m 20d

In domain

1240563-05-9

2 - 15

2m 0d

In domain

1240564-04-8

0 - 15

2m 2d

In domain

1240564-03-7

2 - 10

26.77 days

In domain

For detailed results and domain evaluation, kindly refer the attached QPRF in attached background material section of IUCLID.

Validity criteria fulfilled:
not applicable
Interpretation of results:
not readily biodegradable
Conclusions:
The predicted ultimate half-life values of the individual constituents of the test substance ranged from 27 to 62 days.
Executive summary:

The ready biodegradation and half-life of the test substance was predicted using the CATALOGIC 301C v.11.15. Since the test substance is a UVCB, the ultimate half-life values were predicted for the individual constituents, as described in the boundary composition. SMILES codes were used as the input parameter. The predicted ultimate half-life values of the individual constituents ranged from 27 to 62 days. All the QSAR predictions were within the domain of the QSAR model (LMC, 2018).

Endpoint:
biodegradation in water: ready biodegradability
Remarks:
301B
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:
QSAR prediction from a well-known and acknowledged tool. See below under ''attached background material section' for methodology and QPRF.
Qualifier:
according to guideline
Guideline:
other: REACH guidance on QSARs: Chapter R.6. QSARs and grouping of chemicals
Principles of method if other than guideline:
Since the test substance is a UVCB with similar constituents (varying mainly in the number of acrylates Pentaerythritol backbone as well as adduct formation), the ultimate half-life values were predicted for the individual constituents of boundary composition.
Specific details on test material used for the study:
Input data for the model: SMILES of the individual constituents:

1) CAS Nr.: 3524-68-3; SMILES: C=CC(=O)OCC(CO)(COC(=O)C=C)COC(=O)C=C
2) CAS Nr.: 4986-89-4; SMILES: C=CC(=O)OCC(COC(=O)C=C)(COC(=O)C=C)COC(=O)C=C
3) CAS Nr.: 1174682-57-5; SMILES: C=CC(=O)OCC(COCCC(=O)OCC(COC(=O)C=C)(COC(=O)C=C)COC(=O)C=C)(COC(=O)C=C)COC(=O)C=C
4) CAS Nr.: 1240563-05-9; SMILES: O=C(OCC(COC(C=C)=O)(COCCC(=O)OCC(COC(=O)C=C)(COC(C=C)=O)CO)COC(=O)C=C)C=C
5) CAS Nr.: 1240564-04-8; SMILES: C=CC(=O)OCC(CO)(COCCC(=O)OCC(CO)(COC(=O)C=C)COC(=O)C=C)COC(=O)C=C
6) CAS Nr.: 1240564-03-7; SMILES: C=CC(=O)OCCC(=O)OCC(COC(=O)C=C)(COC(=O)C=C)COC(=O)C=C


*All constituents present at >9.5% have been taken into account for QSAR modelling.
Key result
Parameter:
half-life in days (QSAR/QSPR)
Remarks:
Ultimate half-life (weighted average)
Value:
> 9.5 - < 27.3
Remarks on result:
other: according to CATALOGIC Kinetic 301F v.02.09
Details on results:
For detailed results and domain evaluation, kindly refer the attached QPRF in attached background material section of IUCLID.

Results:

Constituent CAS Nr.

 

Boundary composition (% w/w)

 

CATALOGIC Kinetic 301B v.02.09- ultimate half-life (in days)

 

Domain evaluation

 

3524-68-3

3 – 50 %

10.00

In domain

4986-89-4

10 - 60

8.63

In domain

1174682-57-5

5 -35

27.13

In domain

1240563-05-9

2 - 15

10.38

In domain

1240564-04-8

0 - 15

11.63

In domain

1240564-03-7

2 - 10

9.50

In domain

For detailed results and domain evaluation, kindly refer the attached QPRF in attached background material section of IUCLID.

Validity criteria fulfilled:
yes
Conclusions:
The predicted ultimate half-life values of the individual constituents of the test substance ranged from 9.5 to 27.3 days.
Executive summary:

The ready biodegradation and half-life of the test substance was predicted using the CATALOGIC Kinetic 301B v.02.09. Since the test substance is a UVCB, the ultimate half-life values were predicted for the individual constituents, as described in the boundary composition. SMILES codes were used as the input parameter. The predicted ultimate half-life values of the individual constituents ranged from 9.5 to 27.3 days. All QSAR predictions were within the domain of the model (LMC, 2018).

Endpoint:
biodegradation in water: ready biodegradability
Remarks:
301F
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:
QSAR prediction from a well-known and acknowledged tool. See below under ''attached background material section' for methodology and QPRF.
Qualifier:
according to guideline
Guideline:
other: REACH guidance on QSARs: Chapter R.6. QSARs and grouping of chemicals
Principles of method if other than guideline:
Since the test substance is a UVCB with similar constituents (varying mainly in the number of acrylates Pentaerythritol backbone as well as adduct formation), the ultimate half-life values were predicted for the individual constituents of boundary composition.
Specific details on test material used for the study:
Input data for the model: SMILES of the individual constituents:

1) CAS Nr.: 3524-68-3; SMILES: C=CC(=O)OCC(CO)(COC(=O)C=C)COC(=O)C=C
2) CAS Nr.: 4986-89-4; SMILES: C=CC(=O)OCC(COC(=O)C=C)(COC(=O)C=C)COC(=O)C=C
3) CAS Nr.: 1174682-57-5; SMILES: C=CC(=O)OCC(COCCC(=O)OCC(COC(=O)C=C)(COC(=O)C=C)COC(=O)C=C)(COC(=O)C=C)COC(=O)C=C
4) CAS Nr.: 1240563-05-9; SMILES: O=C(OCC(COC(C=C)=O)(COCCC(=O)OCC(COC(=O)C=C)(COC(C=C)=O)CO)COC(=O)C=C)C=C
5) CAS Nr.: 1240564-04-8; SMILES: C=CC(=O)OCC(CO)(COCCC(=O)OCC(CO)(COC(=O)C=C)COC(=O)C=C)COC(=O)C=C
6) CAS Nr.: 1240564-03-7; SMILES: C=CC(=O)OCCC(=O)OCC(COC(=O)C=C)(COC(=O)C=C)COC(=O)C=C


*All constituents present at >9.5% have been taken into account for QSAR modelling.
Key result
Parameter:
half-life in days (QSAR/QSPR)
Remarks:
Ultimate half-life (weighted average)
Value:
> 11.1 - < 15.1
Remarks on result:
other: according to CATALOGIC Kinetic 301F v.13.16
Details on results:
For detailed results and domain evaluation, kindly refer the attached QPRF in attached background material section of IUCLID.

Results:

Constituent CAS Nr.

 

Boundary composition (% w/w)

 

CATALOGIC Kinetic 301F v.13.16 - ultimate half-life (in days)

 

Domain evaluation

 

3524-68-3

3 – 50 %

13.63

In domain

4986-89-4

10 - 60

12.13

In domain

1174682-57-5

5 -35

13.50

In domain

1240563-05-9

2 - 15

14.63

In domain

1240564-04-8

0 - 15

15.13

In domain

1240564-03-7

2 - 10

11.13

In domain

For detailed results and domain evaluation, kindly refer the attached QPRF in attached background material section of IUCLID.

Conclusions:
Under the study conditions, as five constituents of the test substance are persistant on the basis of the QSAR prediction the test substance is considered to be persistent (P).
Executive summary:

The ready biodegradation and half-life of the test substance was predicted using the CATALOGIC Kinetic 301F v.13.16. Since the test substance is a UVCB with similar constituents (varying mainly in the number of acrylates Pentaerythritol backbone as well as adduct formation), the ultimate half-life values were predicted for the individual constituents of boundary composition. SMILES codes were used as the input parameter. The predicted ultimate half-life values of the individual constituents ranged from 11 to 15 days. All the QSAR predicitons were within the domain of the QSAR model (LMC, 2018). Under the study conditions, as five constituents of the test substance are persistant on the basis of the QSAR prediction the test substance is considered to be persistent (P).

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From March 12, 2010 to July 12, 2010
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Reason / purpose for cross-reference:
reference to same study
Reason / purpose for cross-reference:
reference to other study
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test)
Deviations:
no
Qualifier:
according to guideline
Guideline:
ISO DIS 9439 (Ultimate Aerobic Biodegradability - Method by Analysis of Released Carbon Dioxide)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
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): municipal sewage treatment plant 'Waterschap Aa en Maas", s'Hertogenbosch, The Netherlands
- Storage conditions: fresh sludge was kept under continuous aeration until further treatment. The concentration of suspemded solids in the concentrated sludge was 4.8 g/L
- Preparation of inoculum for exposure: before use, the sludge was allowed to settle (70 min) and the iquid was decanted for use as inoculum at the amount of 10 ml/L of mineral medium. Milli-RO water (ca. 80% total volume) and inoculum (1% final volume) were added to the test bottles. The mixture was aereated with synthetic air overnight to purge the system.
Duration of test (contact time):
28 d
Initial conc.:
21 mg/L
Based on:
test mat.
Initial conc.:
12 mg/L
Based on:
other: TOC
Parameter followed for biodegradation estimation:
CO2 evolution
Details on study design:
TEST CONDITIONS
- Composition of medium: 1 litre mineral medium contains: 10 ml of solution (A), 1 ml of solutions (B) to (D) and Milli-RO water.
Stocksolutions of mineral components:
A) 8.50 g KH2PO4 , 21.75 g K2HPO4, 67.20 g Na2HPO4.12H2O, 0.50 g NH4Cl dissolved in Milli-Q water and made up to 1 litre, pH 7.4 ± 0.2
B) 22.50 g MgSO4.7H2O dissolved in Milli-Q water and made up to 1 litre.
C) 36.40 g CaCl2.2H2O dissolved in Milli-Q water and made up to 1 litre.
D) 0.25 g FeCl3.6H2O dissolved in Milli-Q water and made up to 1 litre.

- Test temperature: between 21.7 and 22.5°C.
- pH:
t=0 d 7.6
t=28 d 7.3-7.6
- pH adjusted: no
- Aeration of dilution water: Not before the test, the test is aerated continuously
- Suspended solids concentration:The concentration of suspended solids was 4.8 g/l in the concentrated sludge (information obtained from the municipal sewage treatment plant).
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: 2 litre all-glass brown coloured bottles
- Number of culture flasks/concentration: Test suspension: containing test substance and inoculum (2 bottles).
Inoculum blank: containing only inoculum (2 bottles)
Positive control: containing reference substance and inoculum (1 bottle).
Toxicity control: containing test substance, reference substance and inoculum (1 bottle).
- Method used to create aerobic conditions: Synthetic air (CO2 < 1 ppm)
A mixture of oxygen (ca. 20%) and nitrogen (ca. 80%)
The synthetic air was sparged through the scrubbing solutions at a rate of approximately 1-2 bubbles per second (ca. 30-100 ml/min).
- Test performed in open system: YES
- Details of trap for CO2 and volatile organics if used: The CO2 produced in each test bottle reacted with the barium hydroxide in the gas scrubbing bottle and precipitated out as barium carbonate. The amount of CO2 produced was determined by titrating the remaining Ba(OH)2 with 0.05 M standardized HCl (1:20 dilution from 1 M HCl (Titrisol® ampul), Merck, Darmstadt, Germany). Phenolphthalein (1% solution in ethanol, Merck) was used as pH-indicator.
Titrations were made every second or third day during the first 10 days, and thereafter at least every fifth day until the 28th day, for the inoculum blank and test suspension. Titrations for the positive and toxicity control were made at least 14 days.

SAMPLING
- Sampling frequency: Titrations were made on day: 2, 5, 7, 9, 14, 19, 23, 27 and 29.
Sampling method: Titration of the whole volume of CO2-absorber. Each time the CO2-absorber nearest to the test bottle was removed for titration; each of the remaining two absorbers was moved one position in the direction of the test bottle. A new CO2-absorber was placed at the far end of the series.

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Abiotic sterile control: no
- Toxicity control: yes
Reference substance:
other: sodium acetate
Key result
Parameter:
% degradation (CO2 evolution)
Value:
14
Sampling time:
28 d
Remarks on result:
other: Duplicate 1; HCl added on the 28th day (last CO2-measurement on the 29th day).
Key result
Parameter:
% degradation (CO2 evolution)
Value:
6
Sampling time:
28 d
Remarks on result:
other: Duplicate 2; HCl added on the 28th day (last CO2-measurement on the 29th day).
Details on results:
In the toxicity control more than 25% biodegradation occurred within 14 days (42%, based on ThCO2). Therefore, the test substance was assumed not to inhibit microbial activity
Results with reference substance:
The positive control substance was biodegraded by at least 60% (83%) within 14 days.

None

Interpretation of results:
other: The relative biodegradation values during the test period revealed 14 and 6% biodegradation of PETIA, for the duplicate bottles tested. Thus, the criterion for ready biodegradability (at least 60% biodegradation within a 10-day window) was not met.
Conclusions:
The substance was not readily biodegradable under the conditions of the study.
Executive summary:

A study was conducted to determine the ready biodegradability of PETIA according to OECD Guideline 301B.

The relative biodegradation values during the test period revealed 14 and 6% biodegradation of the substance for the duplicate bottles tested. There was no toxicity to inoculum and the positive control degraded as expected.

Thus, the criterion for ready biodegradability (at least 60% biodegradation) was not met.

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From28 May, 2015 to 22 July, 2015
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study has been performed according to OECD Guideline, EU Method and ISO Standards in compliance with GLP.
Qualifier:
according to guideline
Guideline:
EU Method C.4-E (Determination of the "Ready" Biodegradability - Closed Bottle Test)
Deviations:
yes
Remarks:
minor: Ammonium chloride was omitted from the medium to prevent oxygen consumption due to nitrification (omission does not result in nitrogen limitation as shown by the biodegradation of the reference compound).
Qualifier:
according to guideline
Guideline:
ISO DIS 9408 (Ultimate Aerobic Biodegradability - Method by Determining the Oxygen Demand in a Closed Respirometer)
Deviations:
yes
Remarks:
minor: Ammonium chloride was omitted from the medium to prevent oxygen consumption due to nitrification (omission does not result in nitrogen limitation as shown by the biodegradation of the reference compound).
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)
Deviations:
yes
Remarks:
minor: Ammonium chloride was omitted from the medium to prevent oxygen consumption due to nitrification (omission does not result in nitrogen limitation as shown by the biodegradation of the reference compound).
GLP compliance:
yes (incl. QA statement)
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
River water was sampled from the Rhine near Heveadorp, The Netherlands (07-05-2015). The nearest plant (Arnhem-Zuid) treating domestic waste water biologically was 3 km upstream. The river water was aerated for 7 d before use to reduce the endogenous respiration. River water without particles was used as inoculum. The particles were removed by sedimentation after 1 d while moderately aerating. The inoculum was not pre-adapted to the test substance.
Duration of test (contact time):
60 d
Initial conc.:
2 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
Test bottles
The test was performed in 0.30 L BOD (biological oxygen demand) bottles with glass stoppers.

Nutrients, stocks and administration
The river water used in the Closed Bottle test was spiked per liter of water with 8.5 mg KH2PO4, 21.75 mg K2HPO4, 33.3 mg Na2HPO4.2H2O, 22.5 mgMgSO4.7H2O, 27.5 mg CaCl2, 0.25 mg FeCl3.6H2O. Ammonium chloride was not added to the river water to prevent nitrification. Test substance was administered using a stock emulsion prepared in deionized water with polyalkoxylate alkylphenol both at a concentration of 1.0 g/L. Additional control bottles contained polyalkoxylate alkylphenol. Sodium acetate was added to the bottles using a stock solution of 1.0 g/L.

Test procedures
Use was made of 10 bottles containing only river water, 6 bottles containing river water and sodium acetate, 10 bottles containing river water with test substance and surfactant, and 10 bottles containing river water with surfactant. The concentrations of the test substance, surfactant and sodium acetate in the bottles were 4.0, 4.0 and 6.7 mg/L, respectively. The zero time bottles were immediately analyzed for dissolved oxygen using an oxygen electrode. The remaining bottles were closed and incubated in the dark. Two duplicate bottles of all series were withdrawn for analyses of the dissolved oxygen concentration at Day 7, 14, 21, and 28. The Closed bottle test was prolonged by measuring the course of the oxygen decrease in the bottles of Day 28 using a special funnel and oxygen electrode.
Reference substance:
acetic acid, sodium salt
Parameter:
% degradation (O2 consumption)
Value:
50
Sampling time:
28 d
Parameter:
% degradation (O2 consumption)
Value:
72
Sampling time:
60 d
Details on results:
Theoretical oxygen demand (ThOD)
The calculated theoretical oxygen demand (ThOD) of the main components pentaerythritol triacrylate and pentaerythritol tetraacrylate are 1.64 and 1.61 mg/mg, respectively. A ThOD of 1.6 mg/mg was therefore used to calculate the biodegradability of the test substance. The ThOD of sodium acetate was 0.8 mg/mg.

Toxicity
Inhibition of the degradation of a well-degradable compound, sodium acetate by the test substance in the closed bottle test was not determined because possible toxicity of test substance to microorganisms degrading acetate is not relevant. Inhibition of the endogenous respiration of the inoculum by the test substance was not detected. Therefore, no inhibition of the biodegradation due to the "high" initial concentration of the test substance is expected.

Test conditions
The pH of the media was 8.0 at the start of the test. The pH of the medium at Day 28 was 7.9 (controls) and 7.8 (test). Temperatures were within the prescribed temperature range of 22 to 24°C.

Validity of the test
The validity of the test is demonstrated by an endogenous respiration of 1.5 mg/L at Day 28. Furthermore, the differences of the replicate values at Day 28 were less than 20%. The biodegradation percentage of the reference substance, sodium acetate, at Day 14 was 83. Finally, the validity of the test was shown by oxygen concentrations >0.5 mg/L in all bottles during the test period.

Biodegradability
The test substance was biodegraded by 25% at Day 28 in the Closed Bottle test. In the prolonged Closed Bottle test this substance was biodegraded by46% at Day 60. These results demonstrate that the test substance is inherently biodegradable.
Results with reference substance:
The biodegradation of the reference substance, sodium acetate, at Day 14 was 81%.

Table: Oxygen consumption (mg/L) and the percentages biodegradation of the test Substance (BOD/ThOD) and reference substance (BOD/ThOD) in the Closed Bottle test

Time (d)

Oxygen consumption (mg/L)

Biodegradation (%)

Test substance

Reference substance

Test substance

Reference substance

0

0.0

0.0

0

0

7

0.3

4.0

9

74

14

0.3

4.4

9

81

21

0.9

 

28

 

28

1.6

 

50

 

42

2.0

 

63

 

60

2.3

 

72

 

Validity criteria fulfilled:
yes
Interpretation of results:
inherently biodegradable
Conclusions:
Under the conditions of the study, the test substance can be considered inherently biodegradable.
Executive summary:

A study was conducted to determine the inherent biodegradability of the test substance according to an extended version of OECD Guideline 301D (prolonged closed bottle test) , in compliance with GLP. The test was performed in 0.30 L BOD (biological oxygen demand) bottles with glass stoppers. There were 10 bottles containing only river water, 6 bottles containing river water and sodium acetate, 10 bottles containing river water with test substance and surfactant, and 10 bottles containing river water with surfactant. The concentrations of test substance, EO-PO-EO block polymer and sodium acetate in the bottles were 2.0 and 6.7 mg/L, respectively. No reduction in the endogenous respiration was observed at Day 7. The test substance was therefore considered to be non-inhibitory to the inoculum. The test was valid, as shown by an endogenous respiration of 1.4 mg/L and by the total mineralization of the reference compound, sodium acetate. Sodium acetate was degraded by 81% of its theoretical oxygen demand after 14 d. Oxygen concentrations remained >0.5 mg/L in all bottles during the test period. The test substance was biodegraded by 50% at Day 28 and by 72% at Day 60. Under the conditions of the study, the test substance can therefore be considered inherently biodegradable.

Description of key information

Key value for chemical safety assessment

Biodegradation in water:
inherently biodegradable, fulfilling specific criteria

Additional information

A study was conducted to determine the ready biodegradability of PETIA according to OECD Guideline 301B. The relative biodegradation values during the test period revealed 14 and 6% biodegradation of the substance for the duplicate bottles tested. There was no toxicity to inoculum and the positive control degraded as expected. Thus, the criterion for ready biodegradability (at least 60% biodegradation) was not met (Desmares-Koopmans, 2010).

A further study was conducted to determine the inherent biodegradability of the test substance according to an extended version of OECD Guideline 301D (prolonged closed bottle test), in compliance with GLP. The test was performed in 0.30 L BOD (biological oxygen demand) bottles with glass stoppers. There were 10 bottles containing only river water, 6 bottles containing river water and sodium acetate, 10 bottles containing river water with test substance and surfactant, and 10 bottles containing river water with surfactant. The concentrations of test substance, EO-PO-EO block polymer and sodium acetate in the bottles were 2.0 and 6.7 mg/L, respectively. No reduction in the endogenous respiration was observed at Day 7. The test substance was therefore considered to be non-inhibitory to the inoculum. The test was valid, as shown by an endogenous respiration of 1.4 mg/L and by the total mineralization of the reference compound, sodium acetate. Sodium acetate was degraded by 81% of its theoretical oxygen demand after 14 d. Oxygen concentrations remained >0.5 mg/L in all bottles during the test period. The test substance was biodegraded by 50% at Day 28 and by 72% at Day 60. Under the conditions of the study, the test substance can therefore be considered inherently biodegradable (Ginkel, 2015).

The ready biodegradation and half-life of the test substance was predicted using the CATALOGIC Kinetic 301B v.02.09. Since the test substance is a UVCB, the ultimate half-life values were predicted for the individual constituents, as described in the boundary composition. SMILES codes were used as the input parameter. The predicted ultimate half-life values of the individual constituents ranged from 9.5 to 27.3 days. All QSAR predictions were within the domain of the model (LMC, 2018).

The ready biodegradation and half-life of the test substance was predicted using the CATALOGIC 301C v.11.15. Since the test substance is a UVCB, the ultimate half-life values were predicted for the individual constituents, as described in the boundary composition. SMILES codes were used as the input parameter. The predicted ultimate half-life values of the individual constituents ranged from 27 to 62 days. All the QSAR predictions were within the domain of the QSAR model (LMC, 2018).

The ready biodegradation and half-life of the test substance was predicted using the CATALOGIC Kinetic 301F v.13.16. Since the test substance is a UVCB, the ultimate half-life values were predicted for the individual constituents, as described in the boundary composition. SMILES codes were used as the input parameter. The predicted ultimate half-life values of the individual constituents ranged from 11 to 15 days. All the QSAR predictions were within the domain of the QSAR model (LMC, 2018).