.alpha.-D-Glucopyranosyl bromide, 2,3,4,6-tetrakis(2,2-dimethylpropanoate)

Biodegradation in water and sediment: simulation tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: sediment simulation testing

Type of information:

(Q)SAR

Adequacy of study:

key 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 limited documentation / justification

Justification for type of information:

In order to identify the relevant degradation products of the substance as a standard information requirement according to Column 1, Section 9.2.3 of Annex IX to REACH and for assessment of potential PBT/vPvB properties, degradation products were predicted using the EAWAG-BBD Pathway Prediction System.

Principles of method if other than guideline:

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
CC(C)(C)C(=O)OCC1C(C(C(C(O1)Br)OC(=O)C(C)(C)C)OC(=O)C(C)(C)C)OC(=O)C(C)(C)C

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 EAWAGBBD 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.

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.

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.

Specific details on test material used for the study:

SMILES code used for prediction: CC(C)(C)C(=O)OCC1C(C(C(C(O1)Br)OC(=O)C(C)(C)C)OC(=O)C(C)(C)C)OC(=O)C(C)(C)C

Oxygen conditions:

aerobic

Inoculum or test system:

other: model calculation

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.

Remarks on result:

other: Two main transformation products were identified. Both are predicted to be readily biodegradable using the QSAR model BIOWIN.

Transformation products:

not specified

Remarks:

See results in "any other information on results incl. tables" below

The EAWAG-BBD PPS system prediction showed that the 2,2 -dimethylpropanoic acid (CAS 75-98-9) parts split off from the parent compound leading to a remaining part (OC1C(O)C(Br)OC(C1O)C([O-])=O). The aerobic likelihood of the prediction was “likely”.

 

Name	CAS number	Smiles
2,2 -dimethylpropanoic acid	75-98-9	CC(C)(C)C([O-])=O
NA	NA	OC1C(O)C(Br)OC(C1O)C([O-])=O

Conclusions:

Likely degradation products of the substance were identified using the EAWAG-BBD PPS system. The prediction showed that the 2,2 -dimethylpropanoic acid (CAS 75-98-9) parts split off from the parent compound leading to a remaining part (OC1C(O)C(Br)OC(C1O)C([O-])=O). The aerobic likelihood of the prediction was “likely”.

Description of key information

A QSAR exercise was carried out for the endpoint coverage. The relevant degradation products of the substance were identified by means of the EAWAG-BBD Pathway Prediction System model. Two main degradation products were identified : the 2,2 -dimethylpropanoic acid (CAS 75-98-9) parts split off from the parent compound leading to a remaining part (OC1C(O)C(Br)OC(C1O)C([O-])=O). Using the QSAR model BIOWIN available in the EPI Suite software, both degradation products were predicted to be readily biodegradable.