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Bioaccumulation: aquatic / sediment

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Endpoint:
bioaccumulation in aquatic species: fish
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 adequate and reliable documentation / justification
Justification for type of information:
The substance is a hydrocarbon UVCB. Standard tests for this endpoint are intended for single substances and are not appropriate for this complex substance. However, this endpoint is fulfilled using quantitative structure property relationships for representative hydrocarbon structures. The BCFBAF 3.01 model is a well characterised and generally accepted bioaccumulation prediction model, used by the USEPA, the OECD and recommended by ECHA. The SMILES input data for the BCFBAF 3.01 model is obtained from the PETRORISK Product Library (see OECD QSAR Toolbox report in 'Attached full study report' and PETRORISK report attached in IUCLID section 13).
Qualifier:
no guideline required
Principles of method if other than guideline:
Software tool(s) used including version: OECD QSAR Toolbox Version 4.4.1
Model(s) used: BCFBAF v3.01 – Arnot-Gobas model which was corrected to 5% lipid content in fish.
The SMILES input data for the BFBAF3.01 model is obtained from the PETRORISK Product Library (see OECD QSAR Toolbox report in ‘Attached full study report’ and PETRORISK report attached in IUCLID section 13).
GLP compliance:
no
Remarks:
(Q)sAR
Key result
Type:
BCF
Value:
>= 4.33 - <= 5 614.57 L/kg
Remarks on result:
other: normalized to a 5% lipid content in fish
Validity criteria fulfilled:
not applicable
Conclusions:
The calculated BCF of this substance ranges from 4.33 - 5614.57 L/kg.
Executive summary:

The substance is a hydrocarbon UVCB. Standard tests for this endpoint are intended for single substances and are not appropriate for this complex substance. However, this endpoint is fulfilled using quantitative structure property relationships for representative hydrocarbon structures. The BCFBAF 3.01 model is a well characterised and generally accepted bioaccumulation prediction model, used by the USEPA, the OECD and recommended by ECHA. The SMILES input data for the BCFBAF 3.01 model is obtained from the PETRORISK Product Library (see OECD QSAR Toolbox report in 'Attached full study report' and PETRORISK report attached in IUCLID section 13).

The calculated BCF of this substance ranges from 4.33 - 5614.57 L/kg.

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:
other: see 'Remark'
Remarks:
Calculation of bioconcentration factors to determine the potential for bioaccumulation of chemicals is acceptable provided that a recognised and scientifically robust method is used. The TGD includes two methods for calculation of a BCF QSAR depending on the molecular weight and log Kow. This approach is considered to be acceptable with restrictions.
Justification for type of information:
A discussion and report on the read across strategy is given as an attachment in IUCLID Section 13.
Reason / purpose for cross-reference:
read-across: supporting information
Principles of method if other than guideline:
BCFBAF v3.00 in EPI Suite™ (Estimation Program Interface for Windows, version 4.0. Syracuse Research Corporation, Syracuse, NY, USA) U.S. Environmental Protection Agency, OPPT)
GLP compliance:
no
Remarks:
Calculation
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
No surrogate or analogue material
Radiolabelling:
no
Details on sampling:
Not applicable (calculated data)
Vehicle:
no
Details on preparation of test solutions, spiked fish food or sediment:
Not applicable (calculated data)
Test organisms (species):
other: calculated
Details on test organisms:
Not applicable (calculated data)
Route of exposure:
other: calculated
Test type:
other: calculated
Hardness:
Not applicable (calculated data)
Test temperature:
Not applicable (calculated data)
pH:
Not applicable (calculated data)
Dissolved oxygen:
Not applicable (calculated data)
TOC:
Not applicable (calculated data)
Salinity:
Not applicable (calculated data)
Details on test conditions:
Not applicable (calculated data)
Nominal and measured concentrations:
Not applicable (calculated data)
Reference substance (positive control):
not required
Details on estimation of bioconcentration:
BASIS FOR CALCULATION OF BCF
_ Estimation software: BCFBAF v.3.00
_ log Kow used : 11.46 (Petrorisk)
Type:
BCF
Value:
22 L/kg
Basis:
other: calculated
Details on kinetic parameters:
Not applicable (calculated data)
Metabolites:
Not applicable (calculated data)
Results with reference substance (positive control):
Not applicable (calculated data)
Details on results:
Log Kow (estimated) : 10.16
Log Kow (experimental): not available from database
Log Kow used by BCF estimates: 11.46 (user entered)

Equation Used to Make BCF estimate:
Log BCF = -0.49 log Kow + 7.554 + Correction

Correction(s): Value
Alkyl chains (8+ -CH2- groups) -0.596

Estimated Log BCF = 1.342 (BCF = 21.98 L/kg wet-wt)

Whole Body Primary Biotransformation Rate Estimate for Fish:

===========================================================

------+-----+--------------------------------------------+---------+---------

 TYPE | NUM | LOG BIOTRANSFORMATION FRAGMENT DESCRIPTION | COEFF | VALUE 

------+-----+--------------------------------------------+---------+---------

 Frag | 2 | Linear C4 terminal chain [CCC-CH3]      | 0.0341 | 0.0682

 Frag | 2 | Methyl [-CH3]                           | 0.2451 | 0.4902

 Frag | 18 | -CH2- [linear]                          | 0.0242 | 0.4354

 Frag | 1 | N-Alkane (linear) ... < C22              | 0.0000 | 0.0000

 L Kow| * | Log Kow = 11.46 (user-entered  )       | 0.3073 | 3.5221

 MolWt| * | Molecular Weight Parameter               |        | -0.7246

 Const| * | Equation Constant                        |        | -1.5058

============+============================================+=========+=========

  RESULT  |       LOG Bio Half-Life (days)           |        | 2.2543

  RESULT  |           Bio Half-Life (days)           |        |  179.6

  NOTE    | Bio Half-Life Normalized to 10 g fish at 15 deg C  |

============+============================================+=========+=========

 

Biotransformation Rate Constant:

 kM (Rate Constant): 0.003859 /day (10 gram fish)

 kM (Rate Constant): 0.00217 /day (100 gram fish)

 kM (Rate Constant): 0.00122 /day (1 kg fish)

 kM (Rate Constant): 0.0006863 /day (10 kg fish)

 

Arnot-Gobas BCF & BAF Methods (including biotransformation rate estimates):

  Estimated Log BCF (upper trophic) = 0.247 (BCF = 1.766 L/kg wet-wt)

  Estimated Log BAF (upper trophic) = 3.443 (BAF = 2771 L/kg wet-wt)

  Estimated Log BCF (mid trophic)  = 0.336 (BCF = 2.168 L/kg wet-wt)

  Estimated Log BAF (mid trophic)  = 3.138 (BAF = 1375 L/kg wet-wt)

  Estimated Log BCF (lower trophic) = 0.365 (BCF = 2.315 L/kg wet-wt)

  Estimated Log BAF (lower trophic) = 2.920 (BAF = 831.8 L/kg wet-wt)

 

Arnot-Gobas BCF & BAF Methods (assuming a biotransformation rate of zero):

  Estimated Log BCF (upper trophic) = 0.585 (BCF = 3.842 L/kg wet-wt)

  Estimated Log BAF (upper trophic) = 4.176 (BAF = 1.499e+004 L/kg wet-wt)

Validity criteria fulfilled:
not applicable
Remarks:
This is a calculated value
Conclusions:
The calculated BCF of icosane is 22 L/kg. This value indicates that icosane is not to be considered as a bioaccumulable substance.
Executive summary:

The QSAR used to calculated the BCF of icosane followed the Reach guidance indications (R7.10.3.2) and so is deemed suitable for the assessment of icosane bioconcentration. The calculated BCF of 22 L/kg indicates that icosane does not belong to bioaccumulable substances.

Description of key information

Hydrocarbons, C14-C20 (even numbered), n-alkanes, isoalkanes, <2% aromatics is a hydrocarbon UVCB. Standard tests for this endpoint are intended for single substances and are not appropriate for this complex substance. However, this endpoint is fulfilled using quantitative structure property relationships for representative hydrocarbon structures. The BCFBAF 3.01 model is a well characterised and generally accepted bioaccumulation prediction model, used by the USEPA, the OECD and recommended by ECHA. The SMILES input data for the BCFBAF 3.01 model is obtained from the PETRORISK Product Library (see OECD QSAR Toolbox report in 'Attached full study report' and PETRORISK report attached in IUCLID section 13).

The calculated BCF of Hydrocarbons, C14-C20 (even numbered), n-alkanes, isoalkanes, <2% aromatics ranges from 4.33 - 5614.57 L/kg.

The BCFWIN v2.16 model within EPISuite 3.12 has been used to estimate the bioaccumulation potential of a number of representative substances. This data is used as a weight of evidence alongside the data reported above.

 

The QSAR used to calculated the BCF of icosane followed the Reach guidance indications (R7.10.3.2) and so is deemed suitable for the assessment of icosane bioconcentration.

 

The calculated BCF of icosane is 22 L/kg. This value indicates that icosane is not to be considered as a bioaccumulable substance.

Key value for chemical safety assessment

BCF (aquatic species):
22 L/kg ww

Additional information

C14-20 Aliphatics (≤2% aromatic) are hydrocarbon UVCBs. Standard tests for this endpoint are intended for single substances and are not appropriate for these complex substances. However, this endpoint has been calculated for representative hydrocarbon structures using the BCFWIN v2.16 model within EPISuite 3.12 as input to the hydrocarbon block method incorporated into the PETRORISK model. The predicted BCFs for hydrocarbons are generally overly conservative since biotransformation is not quantitatively taken into account. Therefore, indirect exposure and resulting risk estimates predicted by PETRORISK are likely to be overestimated. For the purposes of PBT assessment, measured bioaccumulation data for representative hydrocarbon constituents have been used as detailed in section 8 of the CSR.