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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Endpoint:
bioaccumulation: aquatic / sediment
Type of information:
(Q)SAR
Adequacy of study:
weight of evidence
Study period:
Not applicable
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
Justification for type of information:
1. SOFTWARE
OASIS Catalogic v5.11.19

2. MODEL (incl. version number)
BCF base-line model v.02.09

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
CC1CCC(C)=CCCC2C(C)(CCC=1)O2
log Kow = 5.05 (experimental study)

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
See attached QMRF

5. APPLICABILITY DOMAIN
See attached QPRF

6. ADEQUACY OF THE RESULT
See attached QPRF
Qualifier:
according to
Guideline:
other: REACH guidance on QSARs R.6, May 2008
Deviations:
no
Principles of method if other than guideline:
BCF calculated using BCF base-line model.
See attached QMRF and QPRF.
GLP compliance:
no
Specific details on test material used for the study:
The substance is an UVCB substance (1,5,10-trimethylcyclododeca-1,5,9-triene, epoxidised), which is a mixture of various stereoisomers present at variable concentrations (4Z,8E)-1,5,8-trimethyl-13-oxabicyclo[10.1.0]trideca-4,8-diene at 0-70%, (4Z,8E)-1,4,8-trimethyl-13-oxabicyclo[10.1.0]trideca-4,8-diene at 10-20 %, Regio- and geometrical isomers of racemic monoepoxides at 5-15% and Regio- and geometrical isomers of diastereomeric diepoxides at 5-15%.
Radiolabelling:
no
Details on sampling:
Not applicable
Details on preparation of test solutions, spiked fish food or sediment:
Not applicable
Details on test organisms:
Not applicable
Test type:
other: QSAR
Water / sediment media type:
not specified
Hardness:
Not applicable
Test temperature:
Not applicable
pH:
Not applicable
Dissolved oxygen:
Not applicable
TOC:
Not applicable
Salinity:
Not applicable
Details on test conditions:
Not applicable
Nominal and measured concentrations:
Not applicable
Reference substance (positive control):
no
Details on estimation of bioconcentration:
Not applicable
Key result
Type:
BCF
Value:
407 L/kg
Basis:
whole body w.w.
Remarks on result:
other: BCF corrected with mitigating factors
Type:
BCF
Value:
5 649 L/kg
Basis:
whole body w.w.
Remarks on result:
other:
Remarks:
BCF max, not accounting for mitigating factors
Details on kinetic parameters:
Not applicable
Metabolites:
Not applicable
Results with reference substance (positive control):
Not applicable
Details on results:
See details in "Any other information on results incl. tables".
The predicted value from the BCFMAX model determines practically the maximum possible bioconcentration factor (BCFMAX) if the only factor determining the water/organism equilibrium is lipophilicity. This outcome overestimates the bioconcentration potential for most of the chemicals because different chemical and organism properties (called mitigating factors) could reduce significantly the accumulation of substances, such as metabolism, ionization, molecular size, etc. 
Therefore the predictions to be retained are the ones issued from the log BCF corrected 2.57 ± 0.0847 L/kg wet, corresponding to a BCF corrected at 407 ± 1.2 L/kg wet.
Reported statistics:
Not applicable

BCF Baseline-model:

logBCF corrected 2.57 ± 0.0847 L/kg wet, corresponding to a BCF corrected at 407 +/- 1.2 L/kg wet

 

Concomitant related predictions with BCF model:

logBCFmax = 3.752 L/kg wet, corresponding to a BCF max at 5649 L/kg wet (not accounting for mitigating factors).

 

relative mitigating effect of Acids= 0.000

relative mitigating effect of Metabolism= 0.870

relative mitigating effect of Phenols= 0.000

relative mitigating effect of Size= 0.1277

relative mitigating effect of Water solubility= 0.000309

DiamMax Min value = 10.510 Å

DiamMax Max value = 12.137 Å

DiamMax Average = 11.011 Å

 

Validity criteria fulfilled:
yes
Conclusions:
The BCF for the substance, using the BCF base-line model v.02.09 available in OASIS Catalogic v5.11.19, is determined at 407 L/kg using the experimental log Kow value at 5.05, and using mitigating factors that account for the reduction of the bioaccumulation potential of the chemical substance.
Executive summary:

The bioconcentration factor (BCF) of the substance was evaluated with BCF base-line model v.02.09 available in OASIS Catalogic v5.11.19, which fulfilled all OECD principles. The substance fulfils the general property requirements and can be considered within the parametric domain of the model, the substance is in the mechanistic domain of the model but is not fully (100%) in the interpolation structural space. The high percentage of correctly predicted atom centred fragments (at 81.25%, so > 80 %) allows the conclusion that the predictions are relevant. However there is uncertainty in the outcome as a portion the unknown fragments is subject to metabolism. On the other hand, this aliphatic C-oxidation described has a high probability to occur (P 0.9) and the parent substance is transforming into a less lipophilic metabolite. The BCF for the substance is determined at 407 L/kg using the experimental log Kow value at 5.05, and using mitigating factors that account for the reduction of the bioaccumulation potential of the chemical substance. Also, the Maximum bioconcentration factor (BCFmax) is determined at 5649 L/kg. This value determines practically the maximum possible bioconcentration factor if the only factor determining the water/organism equilibrium is lipophilicity. This outcome overestimates the bioconcentration potential for most of the chemicals because different chemical and organism properties (called mitigating factors) could reduce significantly the accumulation of substances, such as metabolism, ionization, molecular size, etc. Therefore the predictions to be retained is the one issued from the log BCF corrected 2.57 ± 0.0847 L/kg wet, corresponding to a BCF corrected at 407 ± 1.2 L/kg wet.

Endpoint:
bioaccumulation: aquatic / sediment
Type of information:
(Q)SAR
Adequacy of study:
weight of evidence
Study period:
Not applicable
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
Remarks:
The value is not an experimental result, however the QSAR model is recommended by the ECHA guidance document on information requirements, is well documented with regard to validation parameters according to OECD principles. Moreover, the substance is fully characterised towards the applicability domain.
Justification for type of information:
1. SOFTWARE
EPISUITE v4.1

2. MODEL (incl. version number)
BCFBAF v3.01

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
CC1CCC(C)=CCCC2C(C)(CCC=1)O2
log Kow = 5.05 (experimental study)

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
See attached QMRF
- Defined endpoint: Bioconcentration Factor (BCF) and Bioaccumulation Factor (BAF).
- Unambiguous algorithm: BCFBAF v3.01 contains two methods for estimating BCFs. In this endpoint study record, one method is presented.
This method has been expanded to calculate both BCF as well as BAF for three general trophic levels of fish. This method is based on the multiple-linear regression-derived equation which is used by the BCFBAF program to estimate the kM Biotransformation Half-Life.
- Defined domain of applicability: The estimation domain for BCF is based on the number of instances given for each correction factor in any of the training set compounds, and the minimum and maximum values for molecular weight and log Kow.
- Appropriate measures of goodness-of-fit and robustness and predictivity: Arnot-Gobas BCF and BAF statistics for the kM biotransformation half-life of the training dataset are; Number = 421 / r² = 0.821 / std deviation = 0.494 / avg deviation = 0.383. For the kM validation dataset; Number = 211 / r² = 0.734 / std deviation = 0.602 / avg deviation = 0.446.
- Mechanistic interpretation: no data

5. APPLICABILITY DOMAIN
See attached QPRF

6. ADEQUACY OF THE RESULT
See attached QPRF
Qualifier:
according to
Guideline:
other: REACH guidance on QSARs R.6, May 2008
Deviations:
no
Principles of method if other than guideline:
BCF calculated using Arnot-Gobas method.
See attached QMRF and QPRF (the QMRF is only available for the former version of the QSAR model).
GLP compliance:
no
Specific details on test material used for the study:
No additional information
Radiolabelling:
no
Details on sampling:
Not applicable
Details on preparation of test solutions, spiked fish food or sediment:
Not applicable
Details on test organisms:
Not applicable
Test type:
other: QSAR
Water / sediment media type:
not specified
Hardness:
Not applicable
Test temperature:
Not applicable
pH:
Not applicable
Dissolved oxygen:
Not applicable
TOC:
Not applicable
Salinity:
Not applicable
Details on test conditions:
Not applicable
Nominal and measured concentrations:
Not applicable
Reference substance (positive control):
no
Details on estimation of bioconcentration:
Not applicable
Key result
Type:
BCF
Value:
>= 4 030 - <= 4 219 L/kg
Basis:
whole body w.w.
Remarks on result:
other: Arnot-Gobas Method, including a biotransformation rate estimates. Depending on the trophic level (upper to lower trophic).
Details on kinetic parameters:
Not applicable
Metabolites:
Not applicable
Results with reference substance (positive control):
Not applicable
Details on results:
Arnot-Gobas Method: It's more relevant to consider the result including biotransformation rate estimates instead of the result assuming a biotransformation rate of zero.
Reported statistics:
Not applicable

TYPE

NUM

LOG BIOTRANSFORMATION FRAGMENT DESCRIPTION

COEFF

VALUE

Frag

Frag

Frag

Frag

Frag

Frag

Frag

L Kow

MolWt

Const

1

1

3

6

1

2

1

*

*

*

Carbon with 4 single bonds & no hydrogens

Aliphatic ether [C-O-C]

Methyl [-CH3]

-CH2- [cyclic]

-CH- [cyclic]

-C=CH [Alkenyl hydrogen]

Number of fused acyclic rings

Log Kow = 5.05 (user-entered)

Molecular Weight Parameter

Equation Constant

-0.2984

-0.0232

0.2451

0.0963

0.0126

0.0988

0.6477

0.3073

-0.2984

-0.0232

0.7353

0.5775

0.0126

0.1977

0.6477

1.5521

-0.5651

-1.5371

RESULT

RESULT

NOTE

Log Bio Half-life (days)

Bio Half-life (days)

Bio Half-life Normalized to 10 g fish at 15°C

1.2991

19.91

Biotransformation rate constant: kM (rate constant) = 0.03482 / day (10 gram fish).

Arnot-Gobas BCFBAF Methods (including biotransformation rate estimates):

Estimated Log BCF (upper trophic) = 3.625 (BCF = 4219 L/Kg wet-wt).

Estimated Log BCF (mid trophic) = 3.620 (BCF = 4173 L/Kg wet-wt).

Estimated Log BCF (lower trophic) = 3.605 (BCF = 4030 L/Kg wet-wt).

Arnot-Gobas BCFBAF Methods (assuming a biotransformation rate of zero):

Estimated Log BCF (upper trophic) = 3.933 (BCF = 8563 L/Kg wet-wt).

Validity criteria fulfilled:
yes
Conclusions:
The BCF for the substance using the Arnot-Gobas method is comprised between 4030 and 4219 L/Kg wet-wt, using the experimental log Kow value at 5.05, and including biotransformation rate estimate.
Executive summary:

The bioconcentration factor (BCF) of the substance was evaluated with BCFBAF model v3.01 from EPI Suite v4.1, which fulfilled all OECD principles. The substance is fully characterised towards the applicability domain. The BCF for the substance using the Arnot-Gobas method is comprised between 4030 and 4219 L/Kg wet-wt, using the experimental log Kow value at 5.05, and including biotransformation rate estimate.

Endpoint:
bioaccumulation: aquatic / sediment
Type of information:
(Q)SAR
Adequacy of study:
weight of evidence
Study period:
Not applicable
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
Remarks:
The value is not an experimental result, however the QSAR model is recommended by the ECHA guidance document on information requirements, is well documented with regard to validation parameters according to OECD principles. Moreover, the substance is fully characterised towards the applicability domain.
Justification for type of information:
1. SOFTWARE
EPISUITE v4.1

2. MODEL (incl. version number)
BCFBAF v3.01

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
CC1CCC(C)=CCCC2C(C)(CCC=1)O2
log Kow = 5.05 (experimental study)

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
See attached QMRF
- Defined endpoint: Bioconcentration Factor (BCF) and Bioaccumulation Factor (BAF).
- Unambiguous algorithm: BCFBAF v3.01 contains two methods for estimating BCFs. In this endpoint study record, one method is presented. This method is based on the original BCFWIN model and classifies a compound as either ionic or non-ionic. Ionic compounds include carboxylic acids, sulfonic acids and salts of sulfonic acids, and charged nitrogen compounds (nitrogen with a +5 valence such as quaternary ammonium compounds). All other compounds are classified as non-ionic.
- Defined domain of applicability: The estimation domain for BCF is based on the minimum and maximum values for molecular weight and log Kow, and the correction factors if needed.
- Appropriate measures of goodness-of-fit and robustness and predictivity: The following gives statistical information for the BCF training and validation datasets (includes ionic and non-ionic compounds). Number = 527 / r² = 0.833 / std deviation = 0.502 / avg deviation = 0.382. For the BCF validation dataset; Number = 158 / r² = 0.82 / std deviation = 0.59 / avg deviation = 0.46.
- Mechanistic interpretation: no data

5. APPLICABILITY DOMAIN
See attached QPRF

6. ADEQUACY OF THE RESULT
See attached QPRF
Qualifier:
according to
Guideline:
other: REACH guidance on QSARs R.6, May 2008
Deviations:
no
Principles of method if other than guideline:
BCF calculated using regression-based estimate method.
See attached QMRF and QPRF (the QMRF is only available for the former version of the QSAR model).
GLP compliance:
no
Specific details on test material used for the study:
No additional information
Radiolabelling:
no
Details on sampling:
Not applicable
Details on preparation of test solutions, spiked fish food or sediment:
Not applicable
Details on test organisms:
Not applicable
Test type:
other: QSAR
Water / sediment media type:
not specified
Hardness:
Not applicable
Test temperature:
Not applicable
pH:
Not applicable
Dissolved oxygen:
Not applicable
TOC:
Not applicable
Salinity:
Not applicable
Details on test conditions:
Not applicable
Nominal and measured concentrations:
Not applicable
Reference substance (positive control):
no
Details on estimation of bioconcentration:
Not applicable
Key result
Type:
BCF
Value:
997.7 L/kg
Basis:
whole body w.w.
Remarks on result:
other: BCF result using the experimental log Kow value
Details on kinetic parameters:
Not applicable
Metabolites:
Not applicable
Results with reference substance (positive control):
Not applicable
Details on results:
See "Any other information on results incl. tables".
Reported statistics:
Not applicable

Log Kow (estimated) : 5.72

Log Kow (experimental): not available from database

Log Kow used by BCF estimates: 5.05 (user entered)

Equation Used to Make BCF estimate:

Log BCF = 0.6598 log Kow - 0.333 + Correction

Correction(s) value: no applicable correction factors

Estimated Log BCF = 2.999 (BCF = 997.7 L/kg wet-wt)

Validity criteria fulfilled:
yes
Conclusions:
The BCF for the substance using the regression-based estimate method is determined at 997.7 L/Kg wet-wt based on the experimental log Kow value, at 5.05.
Executive summary:

The bioconcentration factor (BCF) of the substance was evaluated with BCFBAF model v3.01 from EPI Suite v4.1, which fulfilled all OECD principles. The substance is fully characterised towards the applicability domain. The BCF for the substance using the regression-based estimate method is determined at 997.7 L/Kg wet-wt based on the experimental log Kow value, at 5.05.

Endpoint:
bioaccumulation: aquatic / sediment
Type of information:
(Q)SAR
Adequacy of study:
weight of evidence
Study period:
Not applicable
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
documentation insufficient for assessment
Remarks:
BCF value is determined using calculation method from the Technical Guidance Document in a weight of evidence approach.
Justification for type of information:
1. SOFTWARE
None. Technical Guidance Document (2003)

2. MODEL (incl. version number)
None.

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
log Kow = 5.05 (experimental study)

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
- Defined endpoint: Bioconcentration Factor (BCF).
- Unambiguous algorithm: For a substance with a log Kow of 2 -6, the following linear relationship can be used as developed by Veith et al. (1979): log BCF (fish) = 0.85*log Kow - 0.70. For a substance with a log Kow higher than 6, a parabolic equation can be used: log BCF (fish) = -0.20*log Kow² + 2.74*log Kow - 4.72.
- Defined domain of applicability: The model applicability domain consists of 2 parts: organic chemicals with log Kow of 2 -6 and organic chemicals with log Kow > 6.
- Appropriate measures of goodness-of-fit and robustness and predictivity: n (number of data) = 55; R² (correlation coefficient) = 0.90
- Mechanistic interpretation: No data

5. APPLICABILITY DOMAIN
See details in the Endpoint Study Record

6. ADEQUACY OF THE RESULT
See details in the Endpoint Study Record
Qualifier:
no guideline required
Principles of method if other than guideline:
Calculations based on structure activity.
GLP compliance:
no
Remarks:
(not applicable)
Specific details on test material used for the study:
No additional information
Radiolabelling:
no
Details on sampling:
not applicable
Details on preparation of test solutions, spiked fish food or sediment:
not applicable
Test organisms (species):
no data
Details on test organisms:
No data
Route of exposure:
other: QSAR
Test type:
other: QSAR
Water / sediment media type:
not specified
Hardness:
not applicable
Test temperature:
not applicable
pH:
not applicable
Dissolved oxygen:
not applicable
TOC:
not applicable
Salinity:
not applicable
Details on test conditions:
not applicable
Nominal and measured concentrations:
not applicable
Reference substance (positive control):
not required
Remarks:
QSAR
Details on estimation of bioconcentration:
not applicable
Type:
other: log BCF
Value:
3.592 dimensionless
Remarks on result:
other: TGD, part. II, eq. (74) (logKow = 5.05)
Key result
Type:
BCF
Value:
3 913 L/kg
Basis:
whole body w.w.
Remarks on result:
other: TGD, part. II, eq. (74) (logKow = 5.05)
Details on kinetic parameters:
no data
Metabolites:
no data
Results with reference substance (positive control):
no data
Details on results:
no data
Reported statistics:
no data

Equation used:

log BCF (fish) = 0.85*log Kow - 0.70

Validity criteria fulfilled:
yes
Conclusions:
The BCF value of the substance using the TGD part. II eq. (74) is 3913 L/kg.
Executive summary:

The BCF value of the substance has been assessed by using the TGD part. II eq. (74). The result is shown below:

- TGD part. II eq. (74) approach, log BCF = 3.5925, BCF (L/kg) = 3913

Endpoint:
bioaccumulation: aquatic / sediment
Type of information:
(Q)SAR
Adequacy of study:
weight of evidence
Study period:
Not applicable
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
OASIS Catalogic v5.11.19

2. MODEL (incl. version number)
BCF base-line model v.02.09

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
CC1CCC(C)=CCCC(O)C(C)(O)CCC=1

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
See attached QMRF

5. APPLICABILITY DOMAIN
See attached QPRF

6. ADEQUACY OF THE RESULT
See attached QPRF
Qualifier:
according to
Guideline:
other: REACH guidance on QSARs R.6, May 2008
Deviations:
no
Principles of method if other than guideline:
BCF calculated using BCF base-line model.
See attached QMRF and QPRF.
GLP compliance:
no
Specific details on test material used for the study:
The substance is the hydrolysis product / metabolite of the registered substance (1,5,10-trimethylcyclododeca-1,5,9-triene, epoxidised).
Radiolabelling:
no
Details on sampling:
Not applicable
Details on preparation of test solutions, spiked fish food or sediment:
Not applicable
Details on test organisms:
Not applicable
Test type:
other: QSAR
Water / sediment media type:
not specified
Hardness:
Not applicable
Test temperature:
Not applicable
pH:
Not applicable
Dissolved oxygen:
Not applicable
TOC:
Not applicable
Salinity:
Not applicable
Details on test conditions:
Not applicable
Nominal and measured concentrations:
Not applicable
Reference substance (positive control):
no
Details on estimation of bioconcentration:
Not applicable
Key result
Type:
BCF
Value:
12.9 L/kg
Basis:
whole body w.w.
Remarks on result:
other: BCF corrected with mitigating factors
Type:
BCF
Value:
2 541 L/kg
Basis:
whole body w.w.
Remarks on result:
other:
Remarks:
BCF max, not accounting for mitigating factors
Details on kinetic parameters:
Not applicable
Metabolites:
Not applicable
Results with reference substance (positive control):
Not applicable
Details on results:
See details in "Any other information on results incl. tables".
The predicted value from the BCFMAX model determines practically the maximum possible bioconcentration factor (BCFMAX) if the only factor determining the water/organism equilibrium is lipophilicity. This outcome overestimates the bioconcentration potential for most of the chemicals because different chemical and organism properties (called mitigating factors) could reduce significantly the accumulation of substances, such as metabolism, ionization, molecular size, etc. 
Therefore the predictions to be retained are the ones issued from the log BCF corrected 1.11 ± 0.536 L/kg wet, corresponding to a BCF corrected at 12.9 ± 3.4 L/kg wet.
Reported statistics:
Not applicable

BCF Baseline-model:

logBCF corrected 1.11 ± 0.536 L/kg wet, corresponding to a BCF corrected at 12.9 +/- 3.4 L/kg wet

 

Concomitant related predictions with BCF model:

logBCFmax = 3.405 L/kg wet, corresponding to a BCF max at 2541 L/kg wet (not accounting for mitigating factors).

 

relative mitigating effect of Acids= 0.000

relative mitigating effect of Metabolism= 0.894

relative mitigating effect of Phenols= 0.000

relative mitigating effect of Size= 0.0688

relative mitigating effect of Water solubility= 0.000415

DiamMax Min value = 10.305 Å

DiamMax Max value = 12.076 Å

DiamMax Average = 11.253 Å

 

Validity criteria fulfilled:
yes
Conclusions:
The BCF for the substance, using the BCF base-line model v.02.09 available in OASIS Catalogic v5.11.19, is determined at 12.9 L/kg using mitigating factors that account for the reduction of the bioaccumulation potential of the chemical substance.
Executive summary:

The bioconcentration factor (BCF) of the hydrolysis product / metabolite of 1,5,10-trimethylcyclododeca-1,5,9-triene epoxidised was evaluated with BCF base-line model v.02.09 available in OASIS Catalogic v5.11.19, which fulfilled all OECD principles.

The substance fulfils into the applicability domain of the model (general properties requirements, structural domain and mechanistic domain).

The BCF for this substance is determined at 12.9 L/kg using mitigating factors that account for the reduction of the bioaccumulation potential of the chemical substance. Also, the Maximum bioconcentration factor (BCFmax) is determined at 2541 L/kg. This value determines practically the maximum possible bioconcentration factor if the only factor determining the water/organism equilibrium is lipophilicity. This outcome overestimates the bioconcentration potential for most of the chemicals because different chemical and organism properties (called mitigating factors) could reduce significantly the accumulation of substances, such as metabolism, ionization, molecular size, etc. Therefore the predictions to be retained is the one issued from the log BCF corrected 1.11 ± 0.536 L/kg wet, corresponding to a BCF corrected at 12.9 ± 3.4 L/kg wet.

Description of key information

Weight of Evidence approach with QSAR predictions:

According to data available, the registered substance seems to be B but not vB (log Kow = 5,05 (so > 4,5) but BCF < 5000 L/kg). However, at pH in the stomach of fish (generally comprised between 2 and 4), hydrolysis occured before biotransformation in liver, and the BCF of the hydrolysis product at acid pH is considerably low (BCF = 12.9 according to OASIS QSAR). Therefore, we can conclude that the registered substance is not Bioaccumulable.

Key value for chemical safety assessment

Additional information

A weight of evidence approach was used to assess the bioaccumulation potential of the registered substance, using QSAR predictions. Two QSAR models (BCF base-line model v02.09 available in OASIS Catalogic v5.11.19, and BCFBAF model v3.01 available in EPI Suite v4.1) and one calculation method (TGD part II) were used.

The relevant estimated BCF values for the registered substance were all comprised between 407 and 4219 L/kg, calculated using the experimental log Kow value at 5.05.

Based on these available data, the registered substance seems to be bioaccumulable (log Kow > 4.5 and BCF > 2000 L/kg) but not very bioaccumulable (BCF < 5000 L/kg) according to PBT criteria.

However, the stomatch of fish is a muscular bag, or tube with a highly acidic internal environment. Unlike the Oesophagus and the Intestines, the stomach is surrounded by a triple layer of non-striated muscle. The outer layer being longitudinal and the inner layer being circular with the middle layer running at an oblique angle to the two of these. Inside these muscular layer is a layer of columnar epithelium. The acidity of the stomach changes depending on whether it is full or not. Secretion of Hydrochloric acid is stimulated by the stretching or expansion of the stomach walls caused by the presence of food, so the stomach is more acid when it is full that when it is empty. In most fish the pH of the stomach varies between 2 and 4*. At these pH values, hydrolysis of the registered substance occured before biotransformation in liver. Indeed, the registered substance is unstable at pH lower than 5.0 (see hydrolysis section of IUCLID). Globally, there is three potentially acid sensitive functionalities in the registered substance and in acidic media, this substance will hydrolyze to give poly-hydroxylated product. The BCF value of this hydrolysis / metabolite product (the diol form) was estimated using the BCF base-line model at 12.9 L/kg. As this value is considerably low, we can conclude that the registered substance is not bioaccumulable.

* Source: http://earthlife.net/fish/digestion.html