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Environmental fate & pathways

Biodegradation in water: screening tests

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Endpoint:
biodegradation in water: ready biodegradability
Type of information:
(Q)SAR
Adequacy of study:
key study
Study period:
2 December 2018 and 3 December 2018
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
EPI Suite
Danish QSAR Database

2. MODEL (incl. version number)
BIOWIN
Battery of Leadscope, SciQSAR and CASE Ultra models

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
Smiles: C1=CC2=C3C(=C(C=C2S(=O)(=O)[O-])S(=O)(=O)[O-])C=CC4=C(C=C(C1=C43)S(=O)(=O)[O-])S(=O)(=O)[O-].[Na+].[Na+].[Na+].[Na+]
Substance name: Tetrasodium 1,3,6,8-pyrenetetrasulfonate
CAS: 59572-10-0

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
KREATiS explanation for Klimisch 2: Final QSAR result is reliable and can reliably replace an experimental result with the OECD Guideline for Testing of Chemicals No. 301: Ready Biodegradability.

5. APPLICABILITY DOMAIN
This QSAR model has been designed to be used for regulatory purposes and based on the QSAR results, this report predicts the consensus endpoint value which would be expected when testing the substance under experimental conditions in a laboratory following the OECD Guideline for Testing of Chemicals No. 301: Ready Biodegradability.

6. ADEQUACY OF THE RESULT
Based on multiple QSAR models applied, Tetrasodium 1,3,6,8-pyrenetetrasulfonate was predicted as non-readily biodegradable.
The final Ready Biodegradability was derived by applying a consensus method on the reliable results derived for individual models. The final QSAR result can be associated with a Klimisch score: K2

Guideline:
other: REACH Guidance on QSARs R.6
Version / remarks:
OECD (2004) Principles for the validation, for regulatory purposes, of (Quantitative) Structure Activity-Relationship Models, http://www.oecd.org/env/ehs/risk-assessment/oecdquantitativestructureactivityrelationshipsprojectqsars.htm
Qualifier:
equivalent or similar to guideline
Guideline:
other: OECD Guideline for Testing of Chemicals No. 301: Ready Biodegradability
Version / remarks:
OECD (2004) Principles for the validation, for regulatory purposes, of (Quantitative) Structure Activity-Relationship Models, http://www.oecd.org/env/ehs/risk-assessment/oecdquantitativestructureactivityrelationshipsprojectqsars.htm
Specific details on test material used for the study:
C1=CC2=C3C(=C(C=C2S(=O)(=O)[O-])S(=O)(=O)[O-])C=CC4=C(C=C(C1=C43)S(=O)(=O)[O-])S(=O)(=O)[O-].[Na+].[Na+].[Na+].[Na+]
Key result
Parameter:
probability of ready biodegradability (QSAR/QSPR)
Remarks on result:
not readily biodegradable based on QSAR/QSPR prediction

Resutls with EPI Suite BIOWIN:

Biowin1 (Linear Model Prediction) : Does not Biodegrades Fast

Biowin2 (Non-Linear Model Prediction): Doest not Biodegrades Fast

Biowin3 (Ultimate Biodegradation Timeframe): Months

Biowin4 (Primary Biodegradation Timeframe): Weeks-Months

Biowin5 (MITI Linear Model Prediction) : Not Readily Degradable

Biowin6 (MITI Non-Linear Model Prediction): Not Readily Degradable

Biowin7 (Anaerobic Model Prediction): Does Not Biodegrade Fast

 

Ready Biodegradability Prediction: No (not readily biodegradable)

Danish QSAR Database:

All the three individual models predicted the query substance as: Not readily biodegradable.

The query substance falls within the applicability domain of all these three models.

Final battery prediction: Not-readily biodegradable

Conclusions:
The final result predicted assigned by the study investigator: Tetrasodium 1,3,6,8-pyrenetetrasulfonate is predicted as non readily biodegradable.
Klimisch score assigned by the study investigator for the final prediction: K2
Executive summary:

Introduction. A Quantitative Structure Activity Relationship (QSAR) model was used to predict the Ready Biodegradability of the test item Tetrasodium 1,3,6,8-pyrenetetrasulfonate. This QSAR model has been designed to be used for regulatory purposes and based on the QSAR results, this report predicts the consensus endpoint value which would be expected when testing the substance under experimental conditions in a laboratory following the OECD Guideline for Testing of Chemicals No. 301: Ready Biodegradability.

Methods. The purpose of the in silico study was to predict the Ready Biodegradability of the test item Tetrasodium 1,3,6,8-pyrenetetrasulfonate. This prediction was performed using the following QSAR models:

·       EPI Suite – BIOWIN

·       Battery of Leadscope, SciQSAR and CASE Ultra models integrated into the Danish QSAR Database

 

Results.

Based on multiple QSAR models applied, Tetrasodium 1,3,6,8-pyrenetetrasulfonate was predicted as non-readily biodegradable.

The final Ready Biodegradability was derived by applying a consensus method on the reliable results derived for individual models. The final QSAR result can be associated with a Klimisch score: K2

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Remarks:
Using QSAR
Adequacy of study:
supporting study
Study period:
2 December 2018 and 3 December 2018
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
EPI Suite
Danish QSAR Database

2. MODEL (incl. version number)
BIOWIN
Battery of Leadscope, SciQSAR and CASE Ultra models

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
Smiles: [Na+].[Na+].[Na+].OC1=C2C=CC3=C(C=C(C4=CC=C(C(=C1)S([O-])(=O)=O)C2=C34)S([O-])(=O)=O)S([O-])(=O)=O
Substance name: trisodium 8-hydroxypyrene-1,3,6-trisulfonate
CAS: 6358-69-6

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
KREATiS explanation for Klimisch 2: Final QSAR result is reliable and can reliably replace an experimental result with the OECD Guideline for Testing of Chemicals No. 301: Ready Biodegradability.

5. APPLICABILITY DOMAIN
This QSAR model has been designed to be used for regulatory purposes and based on the QSAR results, this report predicts the consensus endpoint value which would be expected when testing the substance under experimental conditions in a laboratory following the OECD Guideline for Testing of Chemicals No. 301: Ready Biodegradability.

6. ADEQUACY OF THE RESULT
Based on multiple QSAR models applied, trisodium 8-hydroxypyrene-1,3,6-trisulfonate was predicted as non-readily biodegradable.
The final Ready Biodegradability was derived by applying a consensus method on the reliable results derived for individual models. The final QSAR result can be associated with a Klimisch score: K2

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Read-across information

REPORTING FORMAT FOR THE ANALOGUE APPROACH

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
STRUCTURAL SIMILARITY
Both the substances share the same carbon skeleton, which is pyrene. The query substance holds four sulfonates groups while the proposed analogue has one hydroxy group replacing a sulfonate. Both sulfonate and hydroxy groups are hydrophilic in nature. However, the hydroxy group is only ionised at high pHs (pKa of phenol is around 10) while the sulfonate group would remain ionised over the whole range of aqueous pHs. Therefore, Read-Across substance is expected to be slightly less hydrophilic and more volatile than the query substance, which is confirmed by the log KOW and vapour pressure studies.
Both the substances are expected to be stable in pure form or in water, and they are expected to be not volatile (high boiling point, low vapour pressure), highly hydrophilic (low log KOW, high water solubility) due to the presence of four strongly hydrophilic groups.
 
MECHANISMS OF ACTION PREDICTION
The mechanisms of action of both substances are predicted as follows:

Substance MechoA MechoA detail
Query 1.1 non-polar narcosis for all species
Read-Across 1.2 polar narcosis for all species

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
See Test material sections of the source and target records for details.

3. ANALOGUE APPROACH JUSTIFICATION
DISCUSSION AND CONCLUSION
Therefore, both the structures are expected to have very similar (eco)toxicological profile. Moreover, Read-Across substance being less hydrophilic than the query substance and having a more toxic MechoA, the prediction of (eco)toxicological endpoints will be a worst-case scenario, because the less hydrophilic a substance is, the more toxic it is.
Consequently, trisodium 8-hydroxypyrene-1,3,6-trisulfonate is judged to be a good Read-Across for tetrasodium 1,3,6,8-pyrenetetrasulfonate.
Guideline:
other: REACH Guidance on QSARs R.6
Version / remarks:
OECD (2004) Principles for the validation, for regulatory purposes, of (Quantitative) Structure Activity-Relationship Models, http://www.oecd.org/env/ehs/risk-assessment/oecdquantitativestructureactivityrelationshipsprojectqsars.htm
Qualifier:
equivalent or similar to guideline
Guideline:
other: OECD Guideline for Testing of Chemicals No. 301: Ready Biodegradability
Version / remarks:
OECD (2004) Principles for the validation, for regulatory purposes, of (Quantitative) Structure Activity-Relationship Models, http://www.oecd.org/env/ehs/risk-assessment/oecdquantitativestructureactivityrelationshipsprojectqsars.htm
Specific details on test material used for the study:
[Na+].[Na+].[Na+].OC1=C2C=CC3=C(C=C(C4=CC=C(C(=C1)S([O-])(=O)=O)C2=C34)S([O-])(=O)=O)S([O-])(=O)=O
Key result
Parameter:
probability of ready biodegradability (QSAR/QSPR)
Remarks on result:
not readily biodegradable based on QSAR/QSPR prediction
Parameter:
other: OECD Guideline for Testing of Chemicals No. 301: Ready Biodegradability
Remarks on result:
other: Not readily biodegradable - Experimental data from the ECHA dossier:Not-readily biodegradable Reference: https://echa.europa.eu/registration-dossier/-/registered-dossier/17360/5/3/2

Resutls with EPI Suite BIOWIN:

Biowin1 (Linear Model Prediction) : Does not Biodegrades Fast

Biowin2 (Non-Linear Model Prediction): Doest not Biodegrades Fast

Biowin3 (Ultimate Biodegradation Timeframe): Months

Biowin4 (Primary Biodegradation Timeframe): Weeks-Months

Biowin5 (MITI Linear Model Prediction) : Not Readily Degradable

Biowin6 (MITI Non-Linear Model Prediction): Not Readily Degradable

Biowin7 (Anaerobic Model Prediction): Does Not Biodegrade Fast

 

Ready Biodegradability Prediction: No (not readily biodegradable)

Danish QSAR Database:

All the three individual models predicted the query substance as:Not readily biodegradable.

The query substance falls within the applicability domain of all these three models.

Final battery prediction: Not-readily biodegradable

Conclusions:
The final result predicted assigned by the study investigator: trisodium 8-hydroxypyrene-1,3,6-trisulfonate is predicted as non readily biodegradable.
Klimisch score assigned by the study investigator for the final prediction: K2

Description of key information

Multiple Quantitative Structure Activity Relationship (QSAR) models were used to predict the Ready Biodegradability of the test item Tetrasodium 1,3,6,8-pyrenetetrasulfonate. The final Ready Biodegradability was derived by applying a consensus method on the reliable results derived for individual models. The final Ready Biodegradability predicted for

Tetrasodium 1,3,6,8-pyrenetetrasulfonate assigned by the study investigator: non readily biodegradable.The final QSAR result can be associated with a Klimisch score:K2

The same method was used to predict the Ready Biodegradability of the analogue test item trisodium 8-hydroxypyrene-1,3,6-trisulfonate. The final Ready Biodegradability predicted for trisodium 8-hydroxypyrene-1,3,6-trisulfonateassigned by the study investigator: non readily biodegradable. Klimisch score assigned by the study investigtor for the final prediction: K2

Test results published on the ECHA website provided a conclusion of non readily biodegradable for Ready Biodegreadation for the analogue test item trisodium 8

-hydroxypyrene-1,3,6-trisulfonate.

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information

Both structures for the substancesTetrasodium 1,3,6,8-pyrenetetrasulfonate and 8-hydroxypyrene-1,3,6-trisulfonate are expected to have very similar (eco)toxicological profiles. Moreover, the Read-Across substance being less hydrophilic than the query substance and having a more toxic MechoA, the prediction of (eco)toxicological endpoints will be a worst-case scenario, because the less hydrophilic a substance is, the more toxic it is.

Consequently, trisodium 8-hydroxypyrene-1,3,6-trisulfonate is judged to be a good Read-Across for tetrasodium 1,3,6,8-pyrenetetrasulfonate.

Comparison with the QSAR results for the analogue substance, together with the available data on the analogue substance indicate that testing using

8-hydroxypyrene-1,3,6-trisulfonate would be expected to provide a result of non readily biodegradable.