[No public or meaningful name is available]

Bioaccumulation: aquatic / sediment

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

bioaccumulation in aquatic species: fish

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
EPI Suite v4.11 Estimation Programs Interface Suite™ for Microsoft® Windows v 4.11. US EPA, United States Environmental Protection Agency, Washington, DC, USA.

2. MODEL (incl. version number)
BCFBAF v3.01, Arnot-Gobas method

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: EPI Suite v4.11
- Model(s) used: BCFBAF v3.01
Full reference and details of the used formulas can be found in:
1. Arnot JA, Gobas FAPC. 2003. A generic QSAR for assessing the bioaccumulation potential of organic chemicals in aquatic food webs. QSAR and Combinatorial Science 22: 337-345.
- 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 'Justific ation for type of information', 'Attached justification' and/or 'overall remarks'

GLP compliance:

no

Vehicle:

no

Test organisms (species):

other: Fish

Route of exposure:

other: aqueous and dietary

Test type:

other: calculation

Water / sediment media type:

natural water: freshwater

Details on estimation of bioconcentration:

BASIS FOR CALCULATION OF BCF
- Estimation software: EPI Suite v4.11, BCFBAF v3.01
- Result based on calculated log Pow of: 4.71

Type:

BCF

Value:

18.58 L/kg

Basis:

whole body w.w.

Remarks on result:

other: including biotransformation, lower trophic (worst case)

Type:

other: log BCF

Value:

1.269 dimensionless

Basis:

whole body w.w.

Remarks on result:

other: including biotransformation, lower trophic (worst case)

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

Reference 2

Endpoint:

bioaccumulation in aquatic species: fish

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 substance is not fully compliant with 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: the prediction is evaluated on the basis of the model performance on similar substances. For more details see section `overall remarks, attachments´.

Justification for type of information:

1. SOFTWARE
EPI Suite v4.11 Estimation Programs Interface Suite™ for Microsoft® Windows v 4.11. US EPA, United States Environmental Protection Agency, Washington, DC, USA.

2. MODEL (incl. version number)
BCFBAF v3.01, Arnot-Gobas method

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: EPI Suite v4.11
- Model(s) used: BCFBAF v3.01

Full reference and details of the used formulas can be found in:

1. Arnot JA, Gobas FAPC. 2003. A generic QSAR for assessing the bioaccumulation potential of organic chemicals in aquatic food webs. QSAR and Combinatorial Science 22: 337-345.
- 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 'Justific ation for type of information', 'Attached justification' and/or 'overall remarks'

GLP compliance:

no

Vehicle:

no

Test organisms (species):

other: Fish

Route of exposure:

other: aqueous and dietary

Test type:

other: calculation

Water / sediment media type:

natural water: freshwater

Details on estimation of bioconcentration:

BASIS FOR CALCULATION OF BCF
- Estimation software: EPI Suite v4.11, BCFBAF v3.01
- Result based on calculated log Pow of: -8.05

Type:

BCF

Value:

0.94 L/kg

Basis:

whole body w.w.

Remarks on result:

other: including biotransformation, lower trophic (worst case)

Type:

other: log BCF

Value:

-0.027 dimensionless

Basis:

whole body w.w.

Remarks on result:

other: including biotransformation, lower trophic (worst case)

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

Reference 3

Endpoint:

bioaccumulation in aquatic species: fish

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 substance is not fully compliant with 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: the prediction is evaluated on the basis of the model performance on similar substances. For more details see section `overall remarks, attachments´.

Justification for type of information:

1. SOFTWARE
EPI Suite v4.11 Estimation Programs Interface Suite™ for Microsoft® Windows v 4.11. US EPA, United States Environmental Protection Agency, Washington, DC, USA.

2. MODEL (incl. version number)
BCFBAF v3.01, Arnot-Gobas method

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: EPI Suite v4.11
- Model(s) used: BCFBAF v3.01

Full reference and details of the used formulas can be found in:

1. Arnot JA, Gobas FAPC. 2003. A generic QSAR for assessing the bioaccumulation potential of organic chemicals in aquatic food webs. QSAR and Combinatorial Science 22: 337-345.
- 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 'Justific ation for type of information', 'Attached justification' and/or 'overall remarks'

GLP compliance:

no

Vehicle:

no

Test organisms (species):

other: Fish

Route of exposure:

other: aqueous and dietary

Test type:

other: calculation

Water / sediment media type:

natural water: freshwater

Details on estimation of bioconcentration:

BASIS FOR CALCULATION OF BCF
- Estimation software: EPI Suite v4.11, BCFBAF v3.01
- Result based on calculated log Pow of: 20.38

Type:

BCF

Value:

0.94 L/kg

Basis:

whole body w.w.

Remarks on result:

other: including biotransformation, lower trophic (worst case)

Type:

other: log BCF

Value:

-0.027 dimensionless

Basis:

whole body w.w.

Remarks on result:

other: including biotransformation, lower trophic (worst case)

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

Reference 4

Endpoint:

bioaccumulation in aquatic species, other

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 substance could not be fully compliant with 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 1.1.3

2. MODEL (incl. version number)
CAESAR v 2.1.14

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 v1.1.3
- Model(s) used: CAESAR BCF Model version 2.1.14
Full reference and details of the used formulas can be found in:
Zhao, C., Boriani, E., Chana, A., Roncaglioni,A., Benfenati, E. A new hybrid system of QSAR models for predicting bioconcentration factors (BCF). Chemosphere (2008), 73, 1701-1707.
Lombardo A, Roncaglioni A, Boriani E, Milan C, Benfenati E. Assessment and validation of the CAESAR predictive model for bioconcentration factor (BCF) in fish. Chemistry Central Journal (2010), 4 (Suppl 1).
Todeschini R. and Consonni V., Molecular Descriptors for Chemoinformatics, Wiley-VCH, (2009).
- 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

Vehicle:

no

Test organisms (species):

other: Fish

Route of exposure:

aqueous

Justification for method:

minimised test method used to support BCF estimates based on QSAR

Test type:

other: calculation

Water / sediment media type:

natural water: freshwater

Details on estimation of bioconcentration:

BASIS FOR CALCULATION OF BCF
- Estimation software: Vega version 1.1.3, CAESAR v 2.1.14
- Result based on calculated log Pow of: 3.39

Type:

BCF

Value:

2 L/kg

Basis:

whole body w.w.

Type:

other: Log BCF

Value:

0.25 dimensionless

Basis:

whole body w.w.

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

Reference 5

Endpoint:

bioaccumulation in aquatic species, other

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 substance could not be fully compliant with 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 1.1.3

2. MODEL (incl. version number)
CAESAR v 2.1.14

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 v1.1.3
- Model(s) used: CAESAR BCF Model version 2.1.14
Full reference and details of the used formulas can be found in:
Zhao, C., Boriani, E., Chana, A., Roncaglioni,A., Benfenati, E. A new hybrid system of QSAR models for predicting bioconcentration factors (BCF). Chemosphere (2008), 73, 1701-1707.
Lombardo A, Roncaglioni A, Boriani E, Milan C, Benfenati E. Assessment and validation of the CAESAR predictive model for bioconcentration factor (BCF) in fish. Chemistry Central Journal (2010), 4 (Suppl 1).
Todeschini R. and Consonni V., Molecular Descriptors for Chemoinformatics, Wiley-VCH, (2009).
- 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

Vehicle:

no

Test organisms (species):

other: Fish

Route of exposure:

aqueous

Justification for method:

minimised test method used to support BCF estimates based on QSAR

Test type:

other: calculation

Water / sediment media type:

natural water: freshwater

Details on estimation of bioconcentration:

BASIS FOR CALCULATION OF BCF
- Estimation software: Vega version 1.1.3, CAESAR v 2.1.14
- Result based on calculated log Pow of: -4.22

Type:

BCF

Value:

1 L/kg

Basis:

whole body w.w.

Type:

other: Log BCF

Value:

0.07 dimensionless

Basis:

whole body w.w.

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

Reference 6

Endpoint:

bioaccumulation in aquatic species, other

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 substance could not be fully compliant with 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 1.1.3

2. MODEL (incl. version number)
CAESAR v 2.1.14

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 v1.1.3
- Model(s) used: CAESAR BCF Model version 2.1.14
Full reference and details of the used formulas can be found in:
Zhao, C., Boriani, E., Chana, A., Roncaglioni,A., Benfenati, E. A new hybrid system of QSAR models for predicting bioconcentration factors (BCF). Chemosphere (2008), 73, 1701-1707.
Lombardo A, Roncaglioni A, Boriani E, Milan C, Benfenati E. Assessment and validation of the CAESAR predictive model for bioconcentration factor (BCF) in fish. Chemistry Central Journal (2010), 4 (Suppl 1).
Todeschini R. and Consonni V., Molecular Descriptors for Chemoinformatics, Wiley-VCH, (2009).
- 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

Vehicle:

no

Test organisms (species):

other: Fish

Route of exposure:

aqueous

Justification for method:

minimised test method used to support BCF estimates based on QSAR

Test type:

other: calculation

Water / sediment media type:

natural water: freshwater

Details on estimation of bioconcentration:

BASIS FOR CALCULATION OF BCF
- Estimation software: Vega version 1.1.3, CAESAR v 2.1.14
- Result based on calculated log Pow of: 7.8

Type:

BCF

Value:

0.74 L/kg

Basis:

whole body w.w.

Type:

other: Log BCF

Value:

-0.13 dimensionless

Basis:

whole body w.w.

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

Reference 7

Endpoint:

bioaccumulation in aquatic species: fish

Type of information:

other: handbook data

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Handbook data

Qualifier:

no guideline followed

Principles of method if other than guideline:

not applicable: handbook data

GLP compliance:

no

Test organisms (species):

other: not applicable

Route of exposure:

other: not applicable

Remarks on result:

other: Precise results cannot be given, see explanation in any other information on results incl. tables.

"Fatty acid degradation and synthesis are relatively simple processes [...]. The process of degradation converts an aliphatic compound into a set of activated acetyl units (acetyl CoA) that can be processed by the citric acid cycle." p.601

"Free fatty acids and monoglycerides are absorbed by intestinal epithelial cells. Triacylglycerols are resynthesized and packaged with other lipids and apoprotein B-48 to form chylomicrons, which are then released into the lymph system [...] and then released into the blood. These particles bind to membrane-bound lipoprotein lipases [...] where the triacylglycerols are once again degraded into free fatty acids and monoglycerol for transport into the tissue. The triacylglycerols are then resynthesized inside the cell and stored." p. 605

Reference 8

Endpoint:

bioaccumulation in aquatic species: fish

Type of information:

other: review article

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Acceptable, well documented publication which meets basic scientific principles.

Qualifier:

no guideline followed

Principles of method if other than guideline:

Review article describing the metabolism and functions of lipids and fatty acids in fish. Both play major roles as source of metabolic energy in processes as growth and reproduction.

GLP compliance:

no

Test organisms (species):

other: Fish

Route of exposure:

other: not applicable, review article

Test type:

other: not applicable, review article

Remarks on result:

other: Precise results cannot be given, see explanation in any other information on results incl. tables.

- Fatty acid catabolism is the predominant source of energy in many species of fish. The catabolism of fatty acids occurs in the cellular organelles, mitochondria (and peroxisomes). The process is termed beta-oxidation and involves the sequential cleavage of two-carbon units, released as acetyl-CoA, through a cyclic series of reactions catalyzed by several distinct enzyme activities. Activated fatty acids are transported to the mitochondrion in the form of fatty acyltransferase, converted back into fatty acyl-CoA derivatives, and then undergo a round of dehydrogenation, hydration, second hydrogenation, and cleavage steps to produce acetyl-CoA and NADH. Then, the acetyl-CoA can be metabolized via the tricarboxylic cycle to produce more NADH. The NADH will eventually lead to the release of ATP through the process of oxidative phosphorilation, available to be used as energy source.

- Fatty acid oxidation is an important source of energy in several tissues in fish (heart, red muscles, etc). Furthermore, fatty acids are the major source of metabolic energy in the development from egg to adult fish and also during reproduction and lipid depletion processes, such as migrations. They are also involved in the maintainance of the structure and function of cellular biomembranes (as part of phosphoglycerides).

Description of key information

The potential for bioaccumulation of Fatty acids, C16-18 (even numbered), esters with glycerol oligomers is assumed to be low based on all available data.

Additional information

Experimental data on the bioaccumulation potential of fatty acids, C16-18 and C18-unsatd., branched and linear, Bu esters (CAS 163961-32-8) are not available. The high log Kow (> 5) for most components, as an intrinsic chemical property of the substance, indicates a potential for bioaccumulation. However, the information gathered on environmental behaviour and metabolism, in combination with QSAR-estimated values, provide enough evidence (in accordance to the 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), to cover the data requirements of Regulation (EC) No 1907/2006, Annex IX and to state that the substance is likely to show negligible bioaccumulation potential.

Due to the high adsorption potential, an effective removal of the substance in conventional sewage treatment plants (STPs) by sorption to sludge is likely. The poor water solubility 91.9 µg/L), and high estimated log Kow (> 5) indicate that the substance is highly lipophilic. If released to the aquatic environment the substance will extensively adsorb to organic matter and suspended particles. Thus, the bioavailability in the water column will be rapidly reduced. The relevant uptake route in aquatic organisms is expected to be predominantly by ingestion of particle bound substance. If the substance is ingested by organisms a fast metabolisation is anticipated. The substance is expected to be hydrolysed by lipases. The resulting free fatty acids and alcohols are absorbed from the intestine into the blood stream. The alcohols are metabolised primarily in the liver through a series of oxidative steps, finally yielding carbon dioxide (Berg, 2001). Fatty acids are either metabolised via the beta-oxidation pathway in order to generate energy for the cell or reconstituted into glyceride esters and stored in the fat depots in the body (Berg et al., 2001). Lipids and their constituents, fatty acids, are in particularly a major organic constituent of fish and play major roles as sources of metabolic energy (Tocher, 2003). The main route of excretion is via expired air as CO2, and the second route of excretion is by biliary excretion and faeces.

This is supported by further evidence from literature data. This data showed that soil microorganism communities are well capable of degrading fatty acid esters (Hita et al., 1996 and Cecutti et al., 2002) and use them as energy source (Banchio & Gramajo, 1997). Hita et al. investigated the degradation of the model molecule tristearin which is a triglyceride containing of glycerin tri-esterified with stearic acid in three different soils for 4 weeks. The amount of stearic acid increased in considerable amounts during the experiment showing the hydrolytic activity of lipases breaking the ester bonds. The investigation of ester fractions moreover showed the generation of new alkanoic acids (methyl stearate, ethyl stearate and propyl stearate) which were not determined in the controls. Nevertheless the amounts were no longer present after 4 weeks, which leads to the assumption that degradation by soil microorganisms had occurred. The same was shown by Cecutti et al. One soil sample was chosen and incubated with methyl oleate (plant oil) for 120 d. Methyl oleate and its metabolites were completely degraded after 60 d. Streptomyces coelicolor, a common gram-positive soil bacterium uses fatty acids (C4-C18) as sole carbon end energy source indicating that fatty acids are not-toxic and can be used for catabolism (Banchio and Gramajo, 1997). In conclusion, the available literature data showed that soil microorganisms are capable to break-up ester bonds and degrade fatty acids in significant amounts. Moreover, the data indicated the non-toxic properties of fatty acids since they can be used as energy source.

Additional information on bioaccumulation could be gathered using the (Q)SAR model BCFBAF v3.01 (Arnot-Gobas) and VEGA 1.1.3 (Caesar v2.1.14). The estimated BCF values for the main components of Fatty acids, C16-18 (even numbered), esters with glycerol oligomers indicate negligible bioaccumulation in organisms. When including biotransformation, low BCF/BAF values of 0.94 - 18.58 L/kg resulted (Arnot-Gobas estimate, including biotransformation, upper trophic). With VEGA 1.1.3 BCF values of 0.74 - 2 L/kg were determined (Caesar v2.1.14) for the main components of the substance.

The applicability domain of the QSAR model (BCFBAF v3.01) consists of a descriptive domain and a structural domain. The representative components of the UVCB substance are not completely in the applicability domain of the model, e.g. molecular weight and log Kow.

The biotransformation rate in fish is estimated using structural fragments of the representative components to estimate the half-life. In this particular case all structural fragments (three in total) necessary for the prediction of the half-life were included in the training set of the model. However, some of the fragments slightly exceeded the maximum number of instances in the training set which is not expected to have a significant impact on the final result.

For the Q)SAR model VEGA 1.1.3 (Caesar v2.1.14) the one of the main constituent (Diglycerol C16 ester) is suspected to be outside the applicability domain of the model with respect to the calculated applicability domain index (AD Index = 0.85). The AD Index is an important, but not the only one, measure of compliance with the applicability domain. The AD Index value lying on the threshold value of 0.85 indicates that the compound is on the boundary of the applicability domain. AD Index of 1 indicates a full compliance with the applicability domain, and AD Index of 0 a pronounced non-compliance. For both other main constituents (hexyglycerol and tetraglyceride C18 triester), the substance is suspected to be outside the applicability domain of the model, with respect to the calculated applicability domain index (AD Index = 0). The AD Index is an important, but not the only one, measure of compliance with the applicability domain. For the main constituent hexaglycerol the accuracy of prediction for similar molecules found in the training set is good (accuracy index = 0.222) and also the similar molecules found in the training set have experimental values that agree with the predicted value (concordance index = 0.454). Furthermore, the maximum error in prediction of similar molecules found in the training set has a low value, considering the experimental variability. For the main constituent tetraglyceride C18 triester the similar molecules found in the training set have experimental values that agree with the predicted value (concordance index = 0.374). Furthermore, all atom centered fragment of the compound have been found in the compounds of the training set (ACF index = 1). The performance of the model on similar molecules is poor to good of sufficient reliability for the three main components and on this basis the model result for the investigated molecule is considered acceptable with restrictions. The result given as log BCF = -0.13 - 0.25 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.

Even though the components do not fall completely within the applicability domain of the model, the (Q)SAR calculations can be used as supporting indication that the potential of bioaccumulation is low. Moreover, the results support the tendency that substances with high log Kow values (> 9) have a lower potential for bioconcentration as summarized in the ECHA Guidance R.11 and they are not expected to meet the B/vB criterion (ECHA, 2014).

Conclusion

Fatty acids, C16-18 (even numbered), esters with glycerol oligomers is characterized by poor water solubility (91.9 µg/L) and a high log Kow (-8.05 to 20.38) for representative constituents. Based on the physico/chemical properties such as poor water solubility and high potential for adsorption a reduced availability in water is expected. In addition, the available literature data indicates that soil microorganisms are capable to break-up ester bonds and degrade fatty acids in significant amounts. Moreover, the data indicated the non-toxic properties of fatty acids since they can be used as energy source. It can be concluded that the bioaccumulation potential of Fatty acids, C16-18 (even numbered), esters with glycerol oligomers is negligible. This is supported by a low calculated BCF value ranged from 0.94 - 18.58L/kg ww (BCFBAF v3.01, Arnot-Gobas, including biotransformation, upper trophic). With VEGA 1.1.3 BCF values of 0.74 - 2 L/kg were determined (Caesar v2.1.14) for the main components of the substance.