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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Reference
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:
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:
BCF was calculated using Log Kow of 3.6 and the equation defined in the TGD (Log BCF fish = 0.85 . Log Kow -0.7). This is the TGD guideline QSAR
GLP compliance:
not specified
Remarks:
Calculated value therefore this is not applicable.
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material:
not applicable
Details on sampling:
not applicable
Vehicle:
not specified
Details on preparation of test solutions, spiked fish food or sediment:
not applicable
Test organisms (species):
Pimephales promelas
Details on test organisms:
not applicable because this is a calculated value.
Route of exposure:
other: 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
Details on estimation of bioconcentration:
BASIS FOR CALCULATION OF BCF
- Result based on measured log Kow of:4
Key result
Type:
BCF
Value:
501.187 dimensionless
Remarks on result:
other: Temperature and pH not specified
Details on kinetic parameters:
not applicable
Metabolites:
not applicable
Results with reference substance (positive control):
not applicable
Details on results:
not applicable
Reported statistics:
not applicable
Validity criteria fulfilled:
not applicable
Remarks:
This is a calculated value
Conclusions:
The BCF of isohexane was calculated to be 501.187. This calculation indicates that isohexane does not greatly bioaccumulate in the lipids of ecological receptors.
Executive summary:

The QSAR used to calculated the BCF of n-hexane followed the TGD guideline and so is deemed suitable for the assessment of bioconcentration. The calculated BCF of 501.187 indicates that iso-hexane does not greatly bioaccumulate in the lipids of ecological receptors.

Description of key information

A QSAR prediction for 2,2 -dimethylbutane indicates a bioconcentration factor of 154 L/kg w/w.

This is supported by data available for isohexane, which can be used to read-across to 2,2 -dimethylbutane.

The BCF of Isohexane was calculated using a QSAR (Veith and Broderius, 1987), based on a log Kow of 3.6. The QSAR used to calculated the BCF of Isohexane followed the TGD guideline and so is deemed suitable for the assessment of bioconcentration. The calculated BCF of 501.187 indicates that Isohexane does not greatly bioaccumulate in the lipids of ecological receptors.

Key value for chemical safety assessment

BCF (aquatic species):
154 L/kg ww

Additional information