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Environmental fate & pathways

Biodegradation in soil

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Endpoint:
biodegradation in soil: simulation testing
Type of information:
(Q)SAR
Adequacy of study:
weight of evidence
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)
Persistence in soil Model version 1.0.0

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.
Qualifier:
according to guideline
Guideline:
other: REACH Guidance on QSARs R.6
Principles of method if other than guideline:
- Software tool(s) used including version: Vega v1.1.4
- Model(s) used: Persistence in soil Model version 1.0.0

Full reference and details of the used formulas can be found in:
A. Manganaro, F. Pizzo, A. Lombardo, A. Pogliaghi, E. Benfenati, “Predicting persistence in the sediment compartment with a new automatic software based on the k-Nearest Neighbor (k-NN) algorithm”, Chemosphere (2015), accepted paper.
Gouin, T., Cousins, I., Mackay, D., “Comparison of two methods for obtaining degradation halflives”, Chemosphere 56, 2004, 531-535
Gramatica, P., Papa, E., “Screening and ranking of POPs for Global Half-Life: QSAR approaches for prioritization based on molecular structure”, Environ. Sci. Technol. 41, 2007, 2833-9.

- 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
Radiolabelling:
no
Oxygen conditions:
aerobic
Remarks on result:
other: DIPN was predicted to be nP/P: Not persistent (nP) in soil but values falling near to the persistent (P) treshold of 120 days
Transformation products:
not specified

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

Endpoint:
biodegradation in soil: simulation testing
Data waiving:
other justification
Justification for data waiving:
other:
Transformation products:
no

Description of key information

For bis(isopropyl)naphthalene (DIPN; CAS 38640-62-9) no simulation studies on degradation in soil are available. The persistence of DIPN in soil was estimated using the QSAR model VEGA 1.1.4 “Persistence (soil) model” (IRFMN) 1.0.0. For DIPN the model predicts a not entirely certain situation (class nP/P) with a DT50 value falling below but near the P threshold of 120 days. DIPN falls into the applicability domain of the model and the performance of the model on similar molecules is good. The prediction is used as supporting information within a weight of evidence approach for the persistence assessment of bis(isopropyl)naphthalene (CAS 38640-62-9). Based on all available information the isomeric mixture bis(isopropyl)naphthalene (CAS 38640-62-9) needs to be assessed as potentially persistent (P) and/or very persistent (vP). No substantial new findings can be expected from further simulation tests with DIPN isomers. Therefore, further testing is not intended.

Key value for chemical safety assessment

Additional information

QSAR predictions for DIPN degradation in soil

The persistence of DIPN in soil was estimated using the QSAR model VEGA 1.1.4 “Persistence (soil) model” (IRFMN) 1.0.0. For DIPN the model predicts a not entirely certain situation (class nP/P) with a DT50 value falling below but near the P threshold of 120 days. DIPN falls into the applicability domain of the model and the performance of the model on similar molecules is good. The use of the prediction as supporting information within a weight of evidence approach for the persistence assessment of the isomeric mixture bis(isopropy)naphthalene (CAS 38640-62-9) is considered acceptable.