Reaction products of methyloxirane with formaldehyde, oligomeric reaction products with aniline and reaction products of methyloxirane with 2,2'-oxydiethanol

Biodegradation in water and sediment: simulation tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: simulation testing on ultimate degradation in surface water

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

November 2021

Reliability:

1 (reliable without restriction)

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
EAWAG-BBD Pathway Prediction System (http://eawag-bbd.ethz.ch/predict/)

2. MODEL (incl. version number)
EAWAG-BBD Pathway Prediction System: Last updated January 18, 2016.

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
See attached QPRF

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
The EAWAG-BBD Pathway Prediction System predicts (EAWAG-BBD PPS) microbial catabolic reactions using substructure searching, a rule-base, and atom-to-atom mapping. The system is able to recognize organic functional groups found in a compound and predict transformations based on biotransformation rules. The biotransformation rules are based on reactions found in the EAWAG-BBD database or in the scientific literature. The EAWAG-BBD database contains information on microbial biocatalytic reactions and biodegradation pathways for primarily xenobiotic, chemical compounds. Individual reactions and metabolic pathways are presented with information on the starting and intermediate chemical compounds, the organisms that transform the compounds, the enzymes, and the genes.
The EAWAG-BBD (Biocatalysis/Biodegradation Database) is a manually curated database containing information on over 1350 microbial catabolic reactions and about 200 biodegradation pathways. The EAWAG-PPS (Pathway Prediction System) predicts biodegradation pathways using 250 biotransformation rules based on data in the BBD (Biocatalysis/Biodegradation Database) and the scientific literature.
Further details can be found in the attached QMRF

5. APPLICABILITY DOMAIN
Although there is no specifically identified applicability domain for EAWAG-BBD PPS, there are certain chemicals whose biodegradation profile should not be predicted with the system. There are a number of chemical classes that should not be investigated using the current version of the Pathway Prediction System (PPS). Compounds modelled with the EAWAG-BBD PPS can be structurally compared to the compounds present in the EAWAG-BBD database, which presently contains 1400 compounds. The experimental biotransformation data on which the biotransformation rules within the model are based, originate from data on these 1400 substances. More information on the model's applicability domain can be found in the attached QMRF and QPRF.

6. ADEQUACY OF THE RESULT
The results are considered appropriate to fulfil the REACH requirements for identification of degradation products (Annex IX, Section 9.2.3.). The compounds meet the criteria for applicability of the EAWAG-BBD model. None of the constituents fall within the categories of chemicals that should not be investigated with the model. In addition, the (sub)structures of the compounds are well represented within the 1400 compounds in the EAWAG-BBD database.
More information on this can be found in the attached QPRF.

Guideline:

other: REACH guidance on QSARs R.6

Principles of method if other than guideline:

- Software tool(s) used including version: EAWAG-BBD (last update: January 2016)
- Model(s) used: EAWAG-BBD Pathway Prediction System
- Model description: see field 'Justification for non-standard information', see attached QMRF
- Justification of QSAR prediction: see field 'Justification for type of information', see attached QPRF

GLP compliance:

no

Specific details on test material used for the study:

SMILES codes for calculation: see attached QPRF.

Oxygen conditions:

aerobic

Inoculum or test system:

other: model calculation

Details on source and properties of surface water:

The model makes predictions for chemicals exposed to air, moist soil or water at moderate temperature and pH

Parameter followed for biodegradation estimation:

other: The model predicts formation of metabolites via known microbial biodegradation pathways, and provides a likelihood that this would occur under aerobic conditions.

Details on study design:

For the purpose of this QSAR analysis, only products formed through "Very likely" and "Likely" reactions were included.

Key result

Remarks on result:

other: none of the xx potential metabolites of the substance predicted by the EAWAG-BBD Pathway Prediction System model were predicted to be readily biodegradable by the EPI Suite model.

Transformation products:

no

Validity criteria fulfilled:

yes

Conclusions:

The relevant degradation products of DADPM/DEG/PO were identified by means of the EAWAG-BBD Pathway Prediction System model. The biodegradability of each of these degradation products was predicted using the EPI Suite model. All of the identified degradation products were predicted to be not readily biodegradable.

Executive summary:

A QSAR exercise was completed to for the endpoint coverage. Given the complex, partly unknown and variable composition of the parent compound DADPM/DEG/PO, accurate assessment and experimental testing of all individual UVCB constituents is challenging. A QSAR exercise was performed aiming to identify the potential biodegradation pathway each “representative” component of UVCB DADPM/DEG/PO could follow. Once these potential pathways were constructed, the intermediates and end products were assessed for their P (B and T) properties in view of the PBT/vPvB assessment. For this supporting QSAR exercise, freely available tools and software were used (i.e. the EAWAG-BBD Pathway Prediction System model and a number of models available in EPISuite).

Description of key information

A QSAR exercise was completed to for the endpoint coverage. Given the complex, partly unknown and variable composition of the parent compound DADPM/DEG/PO, accurate assessment and experimental testing of all individual UVCB constituents is challenging. A QSAR exercise was performed aiming to identify the potential biodegradation pathway each “representative” component of the parent compound could follow. Once these potential pathways were constructed, the intermediates and end products were assessed for their P (B and T) properties in view of the PBT/vPvB assessment.

 

The relevant degradation products of the substance were identified by means of the EAWAG-BBD Pathway Prediction System model. The biodegradability of each of these degradation products was predicted using the EPI Suite model. All of the identified degradation products were predicted to be readily biodegradable.