Reaction mass of 1-O-α-D-glucopyranosyl-D-mannitol and 6-O-α-D-glucopyranosyl-D-glucitol

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Justification for type of information:

Please refer to the analogue justification attached to IUCLID section 13.

Parameter:

% degradation (CO2 evolution)

Value:

90

Sampling time:

28 d

Remarks on result:

other: mean

Interpretation of results:

readily biodegradable

Conclusions:

Readily biodegradable according to the OECD criteria (90% degradation after 28 d, OECD 301B; read-across).

Executive summary:

One experimental study is available investigating the biodegradation in water. The study was conducted with the read-across source substance isomaltulose (CAS 13718-94-0) according to OECD 301 B (GLP) using activated sludge as inoculum. 90% degradation were reached after 28 days fulfilling the 10-day window requirement. Under the strict conditions of OECD 301 guideline the test item is considered readily biodegradable.

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

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, but not (completely) falling into its applicability domain, with adequate and reliable documentation / justification

Remarks:

The result shows some critical aspects regarding the applicability domain of the model. However, this calculation is used in a weight of evidence approach, in accordance to the REACh Regulation (EC) No 1907/2006, Annex XI General rules for adaptation of the standard testing regime set out in Annexes VII to X, 1.2. It is adequately documented and justified. For more detail see field `overall remarks, attachments´.

Justification for type of information:

1. SOFTWARE
Vega version 1.1.4

2. MODEL (incl. version number)
Ready Biodegradability Model (IRFMN) v. 1.0.9

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: Ready biodegradability model (version 1.0.9)
Full reference and details of the used formulas can be found in:
Meylan W.M., Howard P.H., Boethling R.S. et al. Improved Method for Estimating Bioconcentration / Bioaccumulation Factor from Octanol/Water Partition Coefficient. 1999, Environ. Toxicol. Chem. 18(4): 664-672

- 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

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Remarks on result:

readily biodegradable based on QSAR/QSPR prediction

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

Validity criteria fulfilled:

not applicable

Interpretation of results:

readily biodegradable

Reference 3

Endpoint:

biodegradation in water: ready biodegradability

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, but not (completely) falling into its applicability domain, with adequate and reliable documentation / justification

Remarks:

The result shows some critical aspects regarding the applicability domain of the model. However, this calculation is used in a weight of evidence approach, in accordance to the REACh Regulation (EC) No 1907/2006, Annex XI General rules for adaptation of the standard testing regime set out in Annexes VII to X, 1.2. It is adequately documented and justified. For more detail see field `overall remarks, attachments´.

Justification for type of information:

1. SOFTWARE
Vega version 1.1.4

2. MODEL (incl. version number)
Ready Biodegradability Model (IRFMN) v. 1.0.9

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: Ready biodegradability model (version 1.0.9)
Full reference and details of the used formulas can be found in:
Meylan W.M., Howard P.H., Boethling R.S. et al. Improved Method for Estimating Bioconcentration / Bioaccumulation Factor from Octanol/Water Partition Coefficient. 1999, Environ. Toxicol. Chem. 18(4): 664-672

- 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

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Remarks on result:

readily biodegradable based on QSAR/QSPR prediction

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

Validity criteria fulfilled:

not applicable

Interpretation of results:

readily biodegradable

Description of key information

Isomalt is considered being readily biodegradable. QSAR calculations for both of the main components of Isomalt predict the substance to be readily biodegradable. This is corroborated by experimental data from the read-across substance Isomaltulose, showing 90% degradation after 28 days.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater

Additional information

No studies are available on the biodegradation in water of Reaction mass of 1-O-α-D-glucopyranosyl-D-mannitol and 6-O-α-D-glucopyranosyl-D-glucitol, i.e. Isomalt. Therefore, QSAR calculations were performed for both of the main components, i.e. 1-O-α-D-glucopyranosyl-D-mannitol (1,1-GPM) and 6-O-α-D-glucopyranosyl-D-glucitol (=6-O-α-D-glucopyranosyl-D-sorbitol) (1,6-GPS). The sugar alcohols in both of the disaccharides are isomers of each other and the prediction is the same for both components of Isomalt, i.e. readily biodegradable. The model results are considered acceptable to be used in a weight of evidence approach, in accordance to the REACh Regulation (EC) No 1907/2006, Annex XI General rules for adaptation of the standard testing regime set out in Annexes VII to X, 1.2.

The QSAR prediction is corroborated by the findings of a ready biodegradability study available for Isomaltulose (=6-O-alpha-D-glucopyranosyl-D-fructose), used as source substance in a read-across approach as detailed in the analogue justification attached to IUCLID section 13. In this study according to OECD guideline 301 B and GLP the test substance was degraded to 90% after 28 days, fulfilling the 10 days window, and thus considered as readily biodegradable.

Based on the results detailed above and in general on the molecular structure of the constituents of Isomalt, their intrinsic properties and their natural occurrence and role in common metabolic pathways, Isomalt is considered readily biodegradable and causing no adverse effects towards microorganisms in the environment. For these reasons further testing on biodegradation is not considered justified.