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Biodegradation in water: screening tests

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Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1984-09-11 to 1984-10-09
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Non-GLP guideline study
Qualifier:
according to
Guideline:
OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)
Deviations:
yes
Remarks:
The volume of the test solution was reduced from 3.0 L to 1.5 L.
GLP compliance:
no
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
- Source of inoculum/activated sludge: Bacteria collected from activated sludge of the sewage treatment plant of CH - 4153 Reinach on 10 September 1984
- Preparation of inoculum for exposure: The preparation was carried out according to the method described in the guideline. 20.1 resp. 20.0 mg of the test substance were weighed and aded to the test medium. The volume was adjusted to 200 mL with bidistilled water and aerated for 3 hours.
- Concentration of sludge: 2.0 g/L
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: test medium was prepared according to the method described in the guideline
- Test temperature: 22 ± 2°C

TEST SYSTEM
- Culturing apparatus: 2 Liter flasks equipped with gas inlet and magnetic stirrer.
- Number of culture flasks/concentration: 1
- Method used to create aerobic conditions: Approx. 50 mL/min free of carbon dioxide.
- Measuring equipment: carbon analyzer
- Details of trap for CO2 and volatile organics if used: Titration of the carbon dioxide, absorbed in the absorbers filled wiht 0.025 N barium hydroxide on the days 6, 9, 13, 17, 20, 24, 27 and 28

SAMPLING
- Sampling frequency: 6, 9, 13, 17, 20, 24, 27 and 28 days

CALCULATIONS:
- 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 calculation the formula given in the guideline was used.

ThOC:
- 10 mg test substance are equivalent to 8.051 mg organic carbon.
Reference substance:
aniline
Remarks:
20 mg/L
Parameter:
% degradation (CO2 evolution)
Value:
6
Sampling time:
28 d
Remarks on result:
other: Dose: 10 mg/L
Parameter:
% degradation (CO2 evolution)
Value:
3
Sampling time:
28 d
Remarks on result:
other: Dose: 20 mg/L
Details on results:
The biodegradation calculated as percentage of measured amount of carbondioxide over the theory was:
10 mg test substance/L = 6% in 28 days.
20 mg test substance/L = 3% in 28 days.
Results with reference substance:
20 mg/L = 99% in 28 days.
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:
accepted calculation method
Justification for type of information:
1. SOFTWARE
OASIS Catalogic v5.11.19

2. MODEL (incl. version number)
CATALOGIC 301C v.09.13

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 v5.11.19 BOD 28 days MITI (OECD 301C) v09.13
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:
16
Sampling time:
28 d
Remarks on result:
not readily biodegradable based on QSAR/QSPR prediction
Remarks:
parent compound

- Concomitant predictions :

Not readily biodegradable

Primary Half Life = 11.08 days

Ultimate Half Life = 3 months 17 days

- Predicted value (model result): O2 -consumption (BOD) = 0.16 ± 0.0375

Metabolite prediction:

Biodegradation data of metabolites with estimated quantities ≥0.1% after 28 days (prediction by CATALOGIC 301C v.09.13 implemented in OASIS Catalogic v5.11.19)

SMILES code logKow Quantity after 28d [%] Biodegradation predicted Catalogic 301 C [%] Biodegradation data from OECD Toolbox
CC(c1ccccc1)c1cc(C(C)(C)c2ccccc2)cc(N2Nc3ccccc3N2)c1O 6.8 4.32 10
CC(c1ccccc1)c1cc(N2Nc3ccccc3N2)c(O)c(C(C)(C)c2ccccc2)c1 6.8 4.32 10
CC(C)(c1ccccc1)c1cc(C(C)(C)c2ccc(O)c(O)c2)cc(N2Nc3ccccc3N2)c1O 6.2 0.51 18
CC(C)(c1ccccc1)c1cc(N2Nc3ccccc3N2)c(O)c(C(C)(C)c2ccc(O)c(O)c2)c1 6.2 0.51 18
CC(C)(c1ccccc1)c1cc(C(C)(C)c2ccccc2)cc(N2Nc3ccc(O)c(O)c3N2)c1O 6.2 0.51 17
CC(C)(c1ccccc1)c1cc(C(C)(C)c2ccccc2)cc(N2Nc3cc(O)c(O)cc3N2)c1O 5.9 0.51 17
CC(C)(c1ccccc1)c1cc(N2Nc3ccccc3N2)c(O)c(C(O)=O)c1 5.3 1.39 16
CC(=O)c1cc(C(C)(C)c2ccccc2)cc(N2Nc3ccccc3N2)c1O 5.1 7.47 11
CC(C)(c1ccccc1)c1cc(C(C)(C)C(O)=O)cc(N2Nc3ccccc3N2)c1O 4.9 2.45 10
CC(C)(c1ccccc1)c1cc(N2Nc3ccccc3N2)c(O)c(C(C)(C)C(O)=O)c1 4.9 2.45 10
CC(c1ccccc1)c1cc(N2Nc3ccccc3N2)c(O)c(C(O)=O)c1 4.9 0.18 6
CC(C)(c1ccccc1)c1cc(C(O)=O)c(O)c(N2Nc3ccccc3N2)c1O 4.8 6.69 12
CC(c1ccccc1)c1cc(N2Nc3ccccc3N2)c(O)c(C(C)=O)c1 4.6 1.59 3
CC(C)(c1ccccc1)c1cc(C(O)=O)cc(N2Nc3ccccc3N2)c1O 4.5 7.47 12
CC(c1ccccc1)c1cc(C(O)=O)c(O)c(N2Nc3ccccc3N2)c1O 4.4 1.42 3
CC(=O)c1cc(N2Nc3ccccc3N2)c(O)c(C(C)(C)c2ccccc2)c1 4.3 7.47 11
CC(=O)c1cc(C(C)(C)c2ccc(O)c(O)c2)cc(N2Nc3ccccc3N2)c1O 4.1 0.15 13
CC(=O)c1cc(C(C)(C)c2ccccc2)cc(N2Nc3ccc(O)c(O)c3N2)c1O 4.1 0.15 12
CC(c1ccccc1)c1cc(C(O)=O)cc(N2Nc3ccccc3N2)c1O 4.0 1.59 3
CC(C)(c1ccccc1)c1cc(C(O)=O)c(O)c(N2Nc3ccc(O)c(O)c3N2)c1O 3.9 0.14 13
CC(C)(c1ccc(O)c(O)c1)c1cc(C(O)=O)c(O)c(N2Nc3ccccc3N2)c1O 3.9 0.14 15
CC(c1ccccc1)c1cc(C(C)=O)cc(N2Nc3ccccc3N2)c1O 3.8 1.59 3
CC(=O)c1cc(C(C)(C)c2ccccc2)cc(N2Nc3cc(O)c(O)cc3N2)c1O 3.7 0.15 11
CC(C)(c1ccccc1)c1cc(C(O)=O)c(O)c(N2Nc3cc(O)c(O)cc3N2)c1O 3.5 0.14 12
CC(C)(c1ccc(O)c(O)c1)c1cc(C(O)=O)cc(N2Nc3ccccc3N2)c1O 3.5 0.15 15
CC(C)(c1ccccc1)c1cc(C(O)=O)cc(N2Nc3ccc(O)c(O)c3N2)c1O 3.5 0.15 13
CC(=O)c1cc(N2Nc3ccccc3N2)c(O)c(C(C)(C)c2ccc(O)c(O)c2)c1 3.3 0.15 14
CC(=O)c1cc(N2Nc3ccc(O)c(O)c3N2)c(O)c(C(C)(C)c2ccccc2)c1 3.3 0.15 12
CC(C)(c1ccccc1)c1cc(C(O)=O)cc(N2Nc3cc(O)c(O)cc3N2)c1O 3.2 0.15 12
CC(C)(c1cc(N2Nc3ccccc3N2)c(O)c(C(O)=O)c1)C(O)=O 3.0 0.10 3
CC(=O)c1cc(N2Nc3cc(O)c(O)cc3N2)c(O)c(C(C)(C)c2ccccc2)c1 3.0 0.15 12
CC(=O)c1cc(C(C)(C)C(O)=O)cc(N2Nc3ccccc3N2)c1O 2.8 0.92 1
CC(=O)c1cc(C(O)=O)c(O)c(N2Nc3ccccc3N2)c1O 2.7 5.01 1
Oc1c(N2Nc3ccccc3N2)cc(C(O)=O)cc1C(O)=O 2.6 0.42 4
CC(C)(c1cc(C(O)=O)c(O)c(N2Nc3ccccc3N2)c1O)C(O)=O 2.5 0.80 0
CC(=O)c1cccc(N2Nc3ccccc3N2)c1O 2.4 0.20 1
CC(=O)c1cc(N2Nc3ccccc3N2)c(O)c(C(O)=O)c1 2.4 0.42 4
CC(=O)c1cc(C(O)=O)cc(N2Nc3ccccc3N2)c1O 2.3 5.72 1
CC(C)(c1cc(C(O)=O)cc(N2Nc3ccccc3N2)c1O)C(O)=O 2.2 0.90 1
CC(=O)c1cc(C(C)=O)cc(N2Nc3ccccc3N2)c1O 2.1 5.52 1
c1ccccc1 2.0 41.62 5 readily
CC(=O)c1cc(N2Nc3ccccc3N2)c(O)c(C(C)(C)C(O)=O)c1 2.0 0.92 1
OC(=O)c1ccccc1 1.9 5.31 93 readily
Oc1ccc(C(O)=O)cc1N1Nc2ccccc2N1 1.9 0.20 1
Oc1c(C(O)=O)cc(C(O)=O)c(O)c1N1Nc2ccccc2N1 1.8 4.89 1
CC(=O)c1ccccc1 1.7 0.74 27 readily
CC(=O)c1ccc(O)c(N2Nc3ccccc3N2)c1 1.7 0.20 1
CC(=O)c1cc(C(O)=O)cc(N2Nc3ccc(O)c(O)c3N2)c1O 1.4 0.12 3
OCC(=O)c1cc(C(O)=O)c(O)c(N2Nc3ccccc3N2)c1O 1.2 0.19 10
CC(=O)c1cc(C(C)=O)cc(N2Nc3ccc(O)c(O)c3N2)c1O 1.2 0.12 3
CC(=CC(O)=O)C(C)=O 1.2 0.12 6
Oc1ccccc1O 1.0 0.37 100 readily
CC(=O)c1cc(C(O)=O)cc(N2Nc3cc(O)c(O)cc3N2)c1O 1.0 0.12 1
Oc1ccc(C(O)=O)cc1O 0.9 0.23 91
Oc1ccc2c(c1O)NN(c1c(O)c(C(O)=O)cc(C(O)=O)c1O)N2 0.8 0.21 3
CC(=O)c1cc(C(C)=O)cc(N2Nc3cc(O)c(O)cc3N2)c1O 0.8 0.12 1
CC(=O)c1ccc(O)c(O)c1 0.7 0.23 66
Oc1cc2c(cc1O)NN(c1c(O)c(C(O)=O)cc(C(O)=O)c1O)N2 0.5 0.21 1
CC(=O)C(=C)CC(O)=O 0.2 0.12 6
OC(=O)CC(=CC(O)=O)C(O)=O -0.1 2.61 78
OC(C(O)=O)C(O)(CC(O)=O)C(O)=O -1.0 1.79 89
OC(=O)CC(O)=O -1.2 3.25 100 readily
OC(=O)C=O -1.4 0.19 100 readily
OC(=O)C(C(O)=O)C(O)=O -2.1 0.66 97
OC(=O)CC(=O)CC(O)=O -2.3 0.27 100
OC(=O)CC(O)(C(O)=O)C(O)=O -2.5 0.69 93
OC(C(O)=O)C(O)=O -2.5 0.69 90
OC(=O)CC(=O)C(O)=O -2.6 0.19 100
OC(C(=O)CC(O)=O)C(O)=O -2.6 1.10 97
OC(=O)CC(O)(C=O)C(O)=O -2.7 1.10 94


 

Interpretation of results:
not readily biodegradable
Remarks:
parent substance
Conclusions:
The parent substance is not readily biodegradable. 70 metabolites at a quantity >=0.1% could be identified. According to the predicted BOD and (if available) data from the OECD Toolbox some of these metabolites can be regarded as readily biodegradable. However, for the majority of the metabolites a final conclusion about the degradability/persistency cannot be made.
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, but not (completely) falling into its applicability domain, with adequate and reliable documentation / justification
Justification for type of information:
Please refer to QMRF and QPRF in the section "Overall remarks" and "Executive summary", respectively.
Principles of method if other than guideline:
Prediction of ready biodegradability based on EPI Suite v4.11 BIOWIN v4.10.
GLP compliance:
no
Key result
Remarks on result:
other: Ready biodegradability prediction: Substance is not readily biodegradable.
Key result
Remarks on result:
other: Biowin1: Biodegrades fast; Biowin2: Does not biodegrade Fast; Biowin3: Months; Biowin4: Weeks; Biowin5: Does not biodegrade fast; BIOWIN6: Does not biodegrade fast

BIOWIN (v4.10) Program Results:

==============================

SMILES : CC(C)(c1ccccc1)c2cc(c(O)c(c2)C(C)(C)c3ccccc3)n4nc5ccccc5n4

MOL FOR: C30 H29 N3 O1

MOL WT : 447.58

 

--------------------------- BIOWIN v4.10 Results --------------------------

Biowin1 (Linear Model Prediction)   : Biodegrades Fast

Biowin2 (Non-Linear Model Prediction): Does Not Biodegrade Fast

Biowin3 (Ultimate Biodegradation Timeframe): Months

Biowin4 (Primary Biodegradation Timeframe): Weeks

Biowin5 (MITI Linear Model Prediction)   : Does Not Biodegrade Fast

Biowin6 (MITI Non-Linear Model Prediction): Does Not Biodegrade Fast

Biowin7 (Anaerobic Model Prediction): Does Not Biodegrade Fast

Ready Biodegradability Prediction: NO

  

TYPE

NUM

Biowin1 FRAGMENT DESCRIPTION

COEFF

VALUE

Frag

1

Aromatic alcohol [-OH]

0.1158

0.1158

Frag

2

Carbon with 4 single bonds & no hydrogens

-0.1839

-0.3679

Frag

2

Unsubstituted phenyl group (C6H5-)

0.1281

0.2562

MolWt

*

Molecular Weight Parameter

 

-0.2131

Const

*

Equation Constant

 

0.7475

RESULT

Biowin1 (Linear Biodeg Probability)

 

0.5386

 

TYPE

NUM

Biowin2 FRAGMENT DESCRIPTION

COEFF

VALUE

Frag

1

Aromatic alcohol [-OH]

0.9086

0.9086

Frag

2

Carbon with 4 single bonds & no hydrogens

-1.7232

-3.4464

Frag

2

Unsubstituted phenyl group (C6H5-)

1.7991

3.5982

MolWt

*

Molecular Weight Parameter

 

-6.3557

RESULT

Biowin2 (Non-Linear Biodeg Probability)

 

0.0922

A Probability Greater Than or Equal to 0.5 indicates --> Biodegrades Fast

A Probability Less Than 0.5 indicates --> Does NOT Biodegrade Fast

 

TYPE

NUM

Biowin3 FRAGMENT DESCRIPTION

COEFF

VALUE

Frag

1

Aromatic alcohol [-OH]

0.0564

0.0564

Frag

2

Carbon with 4 single bonds & no hydrogens

-0.2121

-0.4242

Frag

2

Unsubstituted phenyl group (C6H5-)

0.0220

0.0440

MolWt

*

Molecular Weight Parameter

 

-0.9891

Const

*

Equation Constant

 

3.1992

RESULT

Biowin3 (Survey Model - Ultimate Biodeg)

1.8862

 

 

TYPE

NUM

Biowin4 FRAGMENT DESCRIPTION

COEFF

VALUE

Frag

1

Aromatic alcohol [-OH]

0.0397

0.0397

Frag

2

Carbon with 4 single bonds & no hydrogens

-0.1534

-0.3069

Frag

2

Unsubstituted phenyl group (C6H5-)

0.0049

0.0098

MolWt

*

Molecular Weight Parameter

 

-0.6458

Const

*

Equation Constant

 

3.8477

RESULT

Biowin4 (Survey Model - Primary Biodeg)

 

2.9446

Result Classification:  5.00 -> hours    4.00 -> days   3.00 -> weeks

(Primary & Ultimate)   2.00 -> months   1.00 -> longer

TYPE

NUM

Biowin5 FRAGMENT DESCRIPTION

COEFF

VALUE

Frag

1

Aromatic alcohol [-OH]

0.0642

0.0642

Frag

2

Carbon with 4 single bonds & no hydrogens

0.0676

0.1352

Frag

16

Aromatic-H

0.0082

0.1315

Frag

4

Methyl [-CH3]

0.0004

0.0016

MolWt

*

Molecular Weight Parameter

 

-1.3316

Const

*

Equation Constant

 

0.7121

RESULT

Biowin5 (MITI Linear Biodeg Probability)

 

-0.2868

TYPE

NUM

Biowin6 FRAGMENT DESCRIPTION

COEFF

VALUE

Frag

1

Aromatic alcohol [-OH]

0.4884

0.4884

Frag

2

Carbon with 4 single bonds & no hydrogens

0.3990

0.7980

Frag

16

Aromatic-H

0.1201

1.9223

Frag

4

Methyl [-CH3]

0.0194

0.0777

MolWt

*

Molecular Weight Parameter

 

-12.9212

RESULT

Biowin6 (MITI Non-Linear Biodeg Probability)

 

0.0008

A Probability Greater Than or Equal to 0.5 indicates --> Readily Degradable

A Probability Less Than 0.5 indicates --> NOT Readily Degradable

Interpretation of results:
not readily biodegradable
Conclusions:
Based on the results of BIOWIN v4.10 the test substance is predicted to be not readily biodegradable.
Executive summary:

QPRF: BIOWIN v4.11 

1.

Substance

See “Test material identity”

2.

General information

 

2.1

Date of QPRF

See “Data Source (Reference)”

2.2

QPRF author and contact details

See “Data Source (Reference)”

3.

Prediction

3.1

Endpoint
(OECD Principle 1)

Endpoint

Biodegradability

Dependent variable

Biodegradability

3.2

Algorithm
(OECD Principle 2)

Model or submodel name

BIOWIN

Model version

v. 4.10

Reference to QMRF

QMRF: Estimation of Aerobic Biodegradability using BIOWIN v4.10 (EPI Suite v4.11): BIOWIN1 to BIOWIN6 and Ready Biodegradability Prediction

Predicted value (model result)

See “Results and discussion”

Input for prediction

- Chemical structure via CAS number or SMILES

Descriptor values

- Structure fragments

- Molecular weight

3.3

Applicability domain
(OECD principle 3)

Domains (Appendix D, On-Line BIOWIN User’s Guide):

1) Molecular weight

See below (Assessment of estimation domain)

2) Fragments:

See below (Assessment of estimation domain)

3.4

The uncertainty of the prediction
(OECD principle 4)

Parameter

BIOWIN model

1

2

3

4

5

6

Total correct

264 / 295

275 / 295

167 / 200

165 / 200

485 / 589

488 / 589

% correct, total

89.5

93.2

83.5

82.5

82.3

82.9

% correct, fast

97.3 (181 / 186)

97.3 (181 / 186)

93.5 (101 / 108)

84.9 (101 / 119)

79.1 (201 / 254)

80.3 (204 / 254)

3.5

The chemical mechanisms according to the model underpinning the predicted result
(OECD principle 5)

The chemical structure influences the biodegradability of the substance. Therefore, chemical fragments were selected having a potential effect on biodegradability. In order to be able to predict the biodegradability probability of substances without these specific fragments, the molecular weight was integrated into the models.

References

- US EPA (2012). On-Line BIOWIN User’s Guide.

Assessment of estimation domain (molecular weight, fragments):

Model:

BIOWIN v4.10 

Substance:

Tin 234

CAS-#:

70321-86-7

SMILES:

CC(C)(c1ccccc1)c2cc(c(O)c(c2)C(C)(C)c3ccccc3)n4nc5ccccc5n4

Molecular weight (g/mol):

447.58

AppendixD - Fragment Coefficients for Biodegradation Models

BIOWIN1 and BIOWIN2: Linear / Non-Linear Biodegradability

Fragment description

Coefficient

 

Training set fragment count

 

 

No. of instances
of each bond
found for the
current substance

 

Linear

Non-linear

Min

Max

No. of compounds in training set containing the fragment

Aromatic alcohol [-OH]

0.11581

0.9086

-

3

46

1

Carbon with 4 single bonds & no hydrogens

-0.18393

-1.7232

-

2

9

2

Unsubstituted phenyl group (C6H5-)

0.12809

1.7991

-

2

25

2

Molecular Weight

---

---

31.06

697.7

 

in range

  

BIOWIN3 and BIOWIN4: Ultimate / Primary biodegradability

Fragment description

Coefficient

 

Training set fragment count

 

 

No. of instances
of each bond
found for the
current substance

 

Ultimate

Primary

Min

Max

No. of compounds in training set containing the fragment

Aromatic alcohol [-OH]

0.05638

0.03969

-

3

21

1

Carbon with 4 single bonds & no hydrogens

-0.21212

-0.15344

-

3

32

2

Unsubstituted phenyl group (C6H5-)

0.02201

0.00489

-

3

22

2

Molecular Weight

---

---

53.06

697.65

-

in range

 

BIOWIN5 and BIOWIN6: MITI Biodegradability Coefficients (Linear / Non-Linear)

Fragment description

Coefficient

 

Training set fragment count

 

 

No. of instances
of each bond
found for the
current substance

 

Linear

Non-Linear

Min

Max

No. of compounds in training set containing the fragment

Aromatic alcohol [-OH]

0.064226

0.48842336

 -

2

65

1

Carbon with 4 single bonds & no hydrogens

0.067617

0.39898879

 -

9

53

2

Aromatic-H

0.008218

0.12014128

 -

15

302

16*

Methyl [-CH3]

0.000411

0.01942827

 -

9

295

4

Molecular Weight

 ---

---

30.02

959.2

-

in range

 

BIOWIN7: Anaerobic Biodegradation Coefficients

Fragment description

Coefficient

 

Min

Max

No. of compounds in training set containing the fragment

No. of instances
of each bond
found for the
current substance

Aromatic alcohol [-OH]

0.080722447

---

-

3

45

1

Carbon with 4 single bonds & no hydrogens

-0.334230083

---

 -

3

5

2

Unsubstituted phenyl group (C6H5-)

0.21818207

---

-

2

23

2

Aromatic-H

-0.095430138

---

 -

13

94

16*

Methyl [-CH3]

-0.079572183

---

 -

4

86

4

Molecular Weight

---

---

46.07

885.46

 

in range

 *Fragment exceeded the maximum number of instances as listed in Appendix D

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, but not (completely) falling into its applicability domain, with adequate and reliable documentation / justification
Justification for type of information:
1. SOFTWARE
VEGA platform v1.1.3

2. MODEL (incl. version number)
Ready Biodegradability model v1.0.9

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
SMILES: Oc1c(cc(cc1C(c2ccccc2)(C)C)C(c3ccccc3)(C)C)N4Nc5ccccc5(N4)

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. 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:
The model is based on the OECD TG 301C - modified MITI -I test data and provides a qualitative evaluation (binary classification) of ready biodegradability properties.
The applicability domain of predictions is assessed using an Applicability Domain Index (ADI) that has values from 0 (worst case) to 1 (best case). The ADI is calculated by grouping several other indices, each one taking into account a particular issue of the applicability domain. Most of the indices are based on the calculation of the most similar compounds found in the training and test set of the model, calculated by a similarity index that consider molecule's fingerprint and structural aspects (count of atoms, rings and relevant fragments).
GLP compliance:
no
Key result
Remarks on result:
not readily biodegradable based on QSAR/QSPR prediction
Remarks:
The substance is outside the Applicability Domain of the model according to AD index.

Experimental value: -

Predicted RB activity: NON Readily Biodegradable

No. alerts for non RB: 2

No. alerts for possible non RB: 2

No. alerts for RB: 0

No. alerts for possible RB: 0

Structural alerts: Non RB alert no. 2 (1-ethyl-3-methylbenzene); Non RB alert no. 12 ((1-phenylethyl)benzene); Possible non RB alert no. 1 (benzylbenzene); Possible non RB alert no. 5 (3-methylaniline)

Reliability: the predicted compound is outside the Applicability Domain of the model

Remarks: none

Interpretation of results:
not readily biodegradable

Description of key information

The parent compound and relevant metabolites are not readily biodegradable (OECD criteria).

Key value for chemical safety assessment

Additional information

The ready biodegradability of the test item (parent compound) was assessed over a 28 day period by the modified Sturm test (OECD 301 B). The nominal test concentrations were 10 and 20 mg a.s./L. The test material attained up to 6 and 3% biodegradation after 28 days whereas the positive control substance (Aniline) was 94.4% degraded after 28 days. These results indicate that the test item cannot be classified readily biodegradable under the conditions of the test.

Furthermore, the degradability of the substance was assessed with different QSAR estimation tools to (1) elucidate its ready biodegradability and (2) identify possible degradation products. The ready biodegradability was assessed with the following QSAR estimation tools:

-      US EPA’s EPISuite estimation program v4.11, Biowin v4.10

-      Ready biodegradability model IRFMN v1.0.9 integrated in the Vegain silicoplatform v1.1.3.

-      Catalogic v5.11.19, Catalogic 301 C v09.13

Catalogic was further used to identify possible degradation products.

According to the US EPA’s EPISuite v4.11, Biowin v4.10 estimation program the substance is not readily biodegradable. The molecular weight of the substance is within the applicability domain of the model. However, the substance exceeded the maximum number of instances of each bond in the Biowin 5 and 6 submodel by 1 instance (aromatic H: 16 instances instead of 15) and in the Biowin 7 submodel by 3 instances (aromatic H: 16 instances instead of 13). These exceedances are not regarded as relevant for the general outcome of the model (not readily biodegradable) especially as the exceeded fragments are only aromatic hydrogens. Thus, the reliability of the prediction is regarded as high.

The Vega IRFMN v1.0.9 model predicted the substance as not readily biodegradable. However, the reliability was low. Only moderately similar compounds with known experimental value in the training set have been found, the accuracy of the prediction for similar molecules found in the training set is not optimal, a prominent number of atom centered fragments of the compound have not been found in the compounds of the training set or are rare fragments. Although the prediction is of low reliability it reflects the experimental result of the OECD 301 B study. Therefore, it was not discarded but used as supporting information.

Catalogic v5.11.19, Catalogic 301 C v09.13 predicted a BOD of 16%. The model’s applicability domain is divided into three subdomains. (1) the parameter domain, (2) the structural fragment domain and (3) the metabolic domain. The substance is within the logKow, molecular weight and water solubility ranges of the parameter domain. However, only 50% of the fragments of the compound were found in correctly predicted training set chemicals. The remaining 50% of the fragments were unknown and not present in the training set chemicals. Thus, the compound is outside of the structural fragments domain. The third subdomain – the metabolic domain – investigates if the compound can be successfully mineralized. The substance is within the metabolic domain. In summary, the substance is not within the total domain of the model, however, the prediction is regarded as reliable. Especially as available experimental data on the degradability – OECD TG 301 B, 3 to 6% degradation – confirm the predicted result of 16%.

In conclusion, the compound is clearly regarded as not readily biodegradable (by OECD criteria).

In addition to the prediction of the ready biodegradability the identification of degradation products was performed with the Catalogic 301 C model especially in regards to the PBT assessment. As mentioned above, the prediction of the model is regarded as suitable. Furthermore, the predicted metabolic pathways are regarded as reliable as the underlying metabolic transformations can be applied to the present substance/its atom-centered fragments and especially because the substance is within the metabolic domain of the model. The model predicted 70 metabolites at a relevant quantity of0.1% after 28d (Table 1). In addition to the identification of the metabolites Catalogic 301 C also predicted the BOD. Additionally, for metabolites0.1% the OECD QSAR Toolbox v3.4 was used to identify available experimental data to conclude on the degradability of the metabolites beyond their predicted degradation value. The information is also listed in Table 1.

Table 1: Metabolites at a quantity0.1% after 28d and further information about the distribution (logKow) and the degradability (data from the OECD QSAR Toolbox).

Quantity [%]

LogKow

Smiles

BOD predicted [%]*

Remarks

Data from OECD QSAR Toolbox**

17.36

7.2

CC(C)(c1ccccc1)c1cc(C(C)(C)c2ccccc2)cc(N2Nc3ccccc3N2)c1O

16

parent

not readily biodegradable

4.32

6.8

CC(c1ccccc1)c1cc(C(C)(C)c2ccccc2)cc(N2Nc3ccccc3N2)c1O

10

metabolite

No data

4.32

6.8

CC(c1ccccc1)c1cc(N2Nc3ccccc3N2)c(O)c(C(C)(C)c2ccccc2)c1

10

metabolite

No data

0.51

6.2

CC(C)(c1ccccc1)c1cc(C(C)(C)c2ccc(O)c(O)c2)cc(N2Nc3ccccc3N2)c1O

18

metabolite

No data

0.51

6.2

CC(C)(c1ccccc1)c1cc(N2Nc3ccccc3N2)c(O)c(C(C)(C)c2ccc(O)c(O)c2)c1

18

metabolite

No data

0.51

6.2

CC(C)(c1ccccc1)c1cc(C(C)(C)c2ccccc2)cc(N2Nc3ccc(O)c(O)c3N2)c1O

17

metabolite

No data

0.51

5.9

CC(C)(c1ccccc1)c1cc(C(C)(C)c2ccccc2)cc(N2Nc3cc(O)c(O)cc3N2)c1O

17

metabolite

No data

1.39

5.3

CC(C)(c1ccccc1)c1cc(N2Nc3ccccc3N2)c(O)c(C(O)=O)c1

16

metabolite

No data

7.47

5.1

CC(=O)c1cc(C(C)(C)c2ccccc2)cc(N2Nc3ccccc3N2)c1O

11

metabolite

No data

2.45

4.9

CC(C)(c1ccccc1)c1cc(C(C)(C)C(O)=O)cc(N2Nc3ccccc3N2)c1O

10

metabolite

No data

2.45

4.9

CC(C)(c1ccccc1)c1cc(N2Nc3ccccc3N2)c(O)c(C(C)(C)C(O)=O)c1

10

metabolite

No data

0.18

4.9

CC(c1ccccc1)c1cc(N2Nc3ccccc3N2)c(O)c(C(O)=O)c1

6

metabolite

No data

6.69

4.8

CC(C)(c1ccccc1)c1cc(C(O)=O)c(O)c(N2Nc3ccccc3N2)c1O

12

metabolite

No data

1.59

4.6

CC(c1ccccc1)c1cc(N2Nc3ccccc3N2)c(O)c(C(C)=O)c1

3

metabolite

No data

7.47

4.5

CC(C)(c1ccccc1)c1cc(C(O)=O)cc(N2Nc3ccccc3N2)c1O

12

metabolite

No data

1.42

4.4

CC(c1ccccc1)c1cc(C(O)=O)c(O)c(N2Nc3ccccc3N2)c1O

3

metabolite

No data

7.47

4.3

CC(=O)c1cc(N2Nc3ccccc3N2)c(O)c(C(C)(C)c2ccccc2)c1

11

metabolite

No data

0.15

4.1

CC(=O)c1cc(C(C)(C)c2ccc(O)c(O)c2)cc(N2Nc3ccccc3N2)c1O

13

metabolite

No data

0.15

4.1

CC(=O)c1cc(C(C)(C)c2ccccc2)cc(N2Nc3ccc(O)c(O)c3N2)c1O

12

metabolite

No data

1.59

4.0

CC(c1ccccc1)c1cc(C(O)=O)cc(N2Nc3ccccc3N2)c1O

3

metabolite

No data

0.14

3.9

CC(C)(c1ccccc1)c1cc(C(O)=O)c(O)c(N2Nc3ccc(O)c(O)c3N2)c1O

13

metabolite

No data

0.14

3.9

CC(C)(c1ccc(O)c(O)c1)c1cc(C(O)=O)c(O)c(N2Nc3ccccc3N2)c1O

15

metabolite

No data

1.59

3.8

CC(c1ccccc1)c1cc(C(C)=O)cc(N2Nc3ccccc3N2)c1O

3

metabolite

No data

0.15

3.7

CC(=O)c1cc(C(C)(C)c2ccccc2)cc(N2Nc3cc(O)c(O)cc3N2)c1O

11

metabolite

No data

0.14

3.5

CC(C)(c1ccccc1)c1cc(C(O)=O)c(O)c(N2Nc3cc(O)c(O)cc3N2)c1O

12

metabolite

No data

0.15

3.5

CC(C)(c1ccc(O)c(O)c1)c1cc(C(O)=O)cc(N2Nc3ccccc3N2)c1O

15

metabolite

No data

0.15

3.5

CC(C)(c1ccccc1)c1cc(C(O)=O)cc(N2Nc3ccc(O)c(O)c3N2)c1O

13

metabolite

No data

0.15

3.3

CC(=O)c1cc(N2Nc3ccccc3N2)c(O)c(C(C)(C)c2ccc(O)c(O)c2)c1

14

metabolite

No data

0.15

3.3

CC(=O)c1cc(N2Nc3ccc(O)c(O)c3N2)c(O)c(C(C)(C)c2ccccc2)c1

12

metabolite

No data

0.15

3.2

CC(C)(c1ccccc1)c1cc(C(O)=O)cc(N2Nc3cc(O)c(O)cc3N2)c1O

12

metabolite

No data

0.10

3.0

CC(C)(c1cc(N2Nc3ccccc3N2)c(O)c(C(O)=O)c1)C(O)=O

3

metabolite

No data

0.15

3.0

CC(=O)c1cc(N2Nc3cc(O)c(O)cc3N2)c(O)c(C(C)(C)c2ccccc2)c1

12

metabolite

No data

0.92

2.8

CC(=O)c1cc(C(C)(C)C(O)=O)cc(N2Nc3ccccc3N2)c1O

1

metabolite

No data

5.01

2.7

CC(=O)c1cc(C(O)=O)c(O)c(N2Nc3ccccc3N2)c1O

1

metabolite

No data

0.42

2.6

Oc1c(N2Nc3ccccc3N2)cc(C(O)=O)cc1C(O)=O

4

metabolite

No data

0.80

2.5

CC(C)(c1cc(C(O)=O)c(O)c(N2Nc3ccccc3N2)c1O)C(O)=O

0

metabolite

No data

0.20

2.4

CC(=O)c1cccc(N2Nc3ccccc3N2)c1O

1

metabolite

No data

0.42

2.4

CC(=O)c1cc(N2Nc3ccccc3N2)c(O)c(C(O)=O)c1

4

metabolite

No data

5.72

2.3

CC(=O)c1cc(C(O)=O)cc(N2Nc3ccccc3N2)c1O

1

metabolite

No data

0.90

2.2

CC(C)(c1cc(C(O)=O)cc(N2Nc3ccccc3N2)c1O)C(O)=O

1

metabolite

No data

5.52

2.1

CC(=O)c1cc(C(C)=O)cc(N2Nc3ccccc3N2)c1O

1

metabolite

No data

41.62

2.0

c1ccccc1

5

metabolite

Readily biodegradable

0.92

2.0

CC(=O)c1cc(N2Nc3ccccc3N2)c(O)c(C(C)(C)C(O)=O)c1

1

metabolite

No data

5.31

1.9

OC(=O)c1ccccc1

93

metabolite

Readily biodegradable

0.20

1.9

Oc1ccc(C(O)=O)cc1N1Nc2ccccc2N1

1

metabolite

No data

4.89

1.8

Oc1c(C(O)=O)cc(C(O)=O)c(O)c1N1Nc2ccccc2N1

1

metabolite

No data

0.74

1.7

CC(=O)c1ccccc1

27

metabolite

Readily biodegradable

0.20

1.7

CC(=O)c1ccc(O)c(N2Nc3ccccc3N2)c1

1

metabolite

No data

0.12

1.4

CC(=O)c1cc(C(O)=O)cc(N2Nc3ccc(O)c(O)c3N2)c1O

3

metabolite

No data

0.19

1.2

OCC(=O)c1cc(C(O)=O)c(O)c(N2Nc3ccccc3N2)c1O

10

metabolite

No data

0.12

1.2

CC(=O)c1cc(C(C)=O)cc(N2Nc3ccc(O)c(O)c3N2)c1O

3

metabolite

No data

0.12

1.2

CC(=CC(O)=O)C(C)=O

6

metabolite

No data

0.37

1.0

Oc1ccccc1O

100

metabolite

Readily biodegradable

0.12

1.0

CC(=O)c1cc(C(O)=O)cc(N2Nc3cc(O)c(O)cc3N2)c1O

1

metabolite

No data

0.23

0.9

Oc1ccc(C(O)=O)cc1O

91

metabolite

No data

0.21

0.8

Oc1ccc2c(c1O)NN(c1c(O)c(C(O)=O)cc(C(O)=O)c1O)N2

3

metabolite

No data

0.12

0.8

CC(=O)c1cc(C(C)=O)cc(N2Nc3cc(O)c(O)cc3N2)c1O

1

metabolite

No data

0.23

0.7

CC(=O)c1ccc(O)c(O)c1

66

metabolite

No data

0.21

0.5

Oc1cc2c(cc1O)NN(c1c(O)c(C(O)=O)cc(C(O)=O)c1O)N2

1

metabolite

No data

0.12

0.2

CC(=O)C(=C)CC(O)=O

6

metabolite

No data

2.61

-0.1

OC(=O)CC(=CC(O)=O)C(O)=O

78

metabolite

No data

1.79

-1.0

OC(C(O)=O)C(O)(CC(O)=O)C(O)=O

89

metabolite

No data

3.25

-1.2

OC(=O)CC(O)=O

100

metabolite

Readily biodegradable

0.19

-1.4

OC(=O)C=O

100

metabolite

Readily biodegradable

0.66

-2.1

OC(=O)C(C(O)=O)C(O)=O

97

metabolite

No data

0.27

-2.3

OC(=O)CC(=O)CC(O)=O

100

metabolite

No data

0.69

-2.5

OC(=O)CC(O)(C(O)=O)C(O)=O

93

metabolite

No data

0.69

-2.5

OC(C(O)=O)C(O)=O

90

metabolite

No data

0.19

-2.6

OC(=O)CC(=O)C(O)=O

100

metabolite

No data

1.10

-2.6

OC(C(=O)CC(O)=O)C(O)=O

97

metabolite

No data

1.10

-2.7

OC(=O)CC(O)(C=O)C(O)=O

94

metabolite

No data

*Catalogic v5.11.19, Catalogic 301 C v09.13

**Information on the degradability were derived from the OECD QSAR Toolbox v3.4 including the following databases: (1) Biodegradation in soil OASIS, (2) Biodegradation NITE, (3) ECHA CHEM, and (4) ECOTOX.

The OECD QSAR Toolbox identified only six metabolites (excluding the parent compound) with experimental data. These compounds can be regarded as readily biodegradable. For the other metabolites no experimental data could be found and only the predicted BOD values are available. According to the BOD values from Catalogic the vast majority of the metabolites cannot be regarded as readily biodegradable showing BOD values of <20%.

In an overall conclusion, the parent compound cannot be regarded as readily biodegradable. This is supported by three QSAR models which also classified the compound as not biodegradable. The experimental study according to OECD TG 301 B revealed a degradation rate of 3 to 6% and Catalogic 301 C v09.13 revealed a BOD of 16%. According to these results a certain degree of primary degradation of the parent compound might be assumed. However, the half life is expected to be long. Therefore, and as a worst case, the parent compound is regarded as persistent in the environment. In a subsequent step, Catalogic was used to identify possible degradation products0.1% which are relevant in regards to the PBT assessment. For six of these metabolites experimental data derived from the databases incorporated in the OECD QSAR Toolbox could be identified which clearly lead to the conclusion that these six metabolites are readily biodegradable and not persistent. For the remaining metabolites only predicted BOD values from Catalogic 301 C v09.13 are available. Especially the smaller metabolites showed high BOD values. For these compounds it can reasonably be assumed that they are not persistent, but rather well biodegradable if not even readily biodegradable. However, the larger metabolites showed BOD values less than 20%. For these metabolites a concluding assessment about the persistency cannot be made. Therefore, these metabolites are regarded as persistent in the environment. 

 

 

The QSAR predictions have been conducted in compliance with Regulation (EC) No 1907/2006:

 

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 70321-86-7 (Q)SAR results were used for aerobic biodegradability in water.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 aerobic biodegradability in water are not provided.