(1R)-1-[(4R,4aR,8aS)-2,6-bis(3,4-dimethylphenyl)tetrahydro[1,3]dioxino[5,4-d][1,3]dioxin-4-yl]ethane-1,2-diol

Bioaccumulation: aquatic / sediment

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Administrative data

Endpoint:

bioaccumulation: aquatic / sediment

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

Data source

Reference

Title:

Unnamed

Year:

2012

Materials and methods

Test guideline

Guideline:

other: REACH guidance on QSARs Chapter R.6

Version / remarks:

May 2008

Principles of method if other than guideline:

The BCFBAF Program is an update and expansion of the previous BCFWIN Program that was part of the EPI Suite version 3.20. The update pertains to estimation of Bioconcentration Factor (BCF). The BCFBAF program estimates BCF of an organic compound using the compound's log octanol-water partition coefficient (Kow). For the update, a more recent and better evaluated database of BCF values was used for both training and validation.  The BCF data were re-regressed using the same methodology as in the original BCFWIN program.
The original estimation methodology used by the original BCFWIN program is described in a document prepared for the U.S. Environmental Protection Agency (Meylan et al., 1997). The estimation methodology was then published in journal article (Meylan et al, 1999).  The methodology is described in the Bioconcentration Factor Estimation section.
BCFBAF has been expanded to include estimation of the Biotransformation Rate (kM) in fish and estimation of Bioaccumulation Factor (BAF) by the Arnot-Gobas method (Arnot and Gobas, 2003).

GLP compliance:

no

Remarks:

(not applicable)

Test material

Test material information

Constituent 1

Specific details on test material used for the study:

SMILES: OCC(O)C2OC(OC1COC(OC12)c3ccc(c(c3)C)C)c4ccc(c(c4)C)C

Test organisms

Test organisms (species):

other: Fish, not further specified

Study design

Route of exposure:

other: estimated value

Test type:

other: QSAR

Water / sediment media type:

natural water: freshwater

Test conditions

Reference substance (positive control):

not required

Remarks:

(not applicable)

Details on estimation of bioconcentration:

The estimation for the Bioconcentration factor of the test material was performed with US-EPA software EPWIN/BCFBAF v3.01. The BCFBAF program estimates BCF of an organic compound using the compound's log octanol-water partition coefficient (Kow). BCFBAF has been expanded to include estimation of the Biotransformation Rate (kM) in fish and estimation of Bioaccumulation Factor (BAF) by the Arnot-Gobas method (Arnot and Gobas, 2003).

Results and discussion

Bioaccumulation factor

Bioaccumulation factor 1

Type:

BCF

Value:

43.14 L/kg

Basis:

whole body w.w.

Remarks on result:

other: Regression-based estimate

Bioaccumulation factor 2

Type:

BCF

Value:

40.61 L/kg

Basis:

whole body w.w.

Remarks on result:

other: Arnot-Gobas method, based on mechanistic first principles

Details on kinetic parameters:

Not applicable

Metabolites:

Not applicable

Results with reference substance (positive control):

Not applicable

Reported statistics:

Not applicable

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

(Scientifically accepted calculation method)

Conclusions:

The study report describes a scientifically accepted calculation method for the Bioconcentration factor estimation using the US-EPA software BCFBAF v3.01. No GLP criteria are applicable for the usage of this tool and the QSAR estimation is easily repeatable. The result (regression based estimated BCF = 43.14 L/kg wet-wt; Arnot-Gobas method based estimate BCF (higher trophic level) = 40.61 L/kg wet-wt) is adequate for the regulatory purpose.

Executive summary:

The prediction for the bioconcentration factor (BCF) of the test substance was determined by the computer program BCFBAF v3.01 (EPIWIN software) by US-EPA. Furthermore the whole body primary biotransformation rate estimation for fish was calculated with the notation that the bio half-life normalized to 10 g fish at 15 °C. It is possible to predict the apparent metabolism half-life in fish for three different trophic levels (lower, mid and upper). In general, the bioconcentration factor of a substance describes the accumulation potential of a substance dissolved in water by an aquatic organism. BCFBAF v3.01 calculates also the BAF (Bioaccumulation factor) of the chemical, which is defined as the steady-state (equilibrium) ratio of the substance concentration in an organism to the concentration in the surrounding medium. However, this value is not taken into account for the risk assessment and is not relevant for a registration under REACH Regulation (EC) 1907/2006.

Using the regression-based estimate (traditional method) a BCF of 43.14 L/kg wet-wt was calculated. Using the Arnot-Gobas method, which is based on the mechanistic first principles, the BCF results in a value of 40.61 L/kg wet-wt (upper trophic). The whole body primary biotransformation rate estimate for fish gives a half-life of 0.115 days, whereby the rate constant (kM) for 10 g fish is designated as 6.018 /day. This is taken into account to predict the apparent metabolism half-life in fish for the substance. For the lower trophic level a BCF of 48.28 L/kg wet-wt is calculated, whereas for the mid trophic level the BCF will result in 47.12 L/kg wet-wt and the upper trophic level gives a value of 40.61 L/kg wet-wt.

All values are well below the lowest BCF value regarded as critial during the PBT Assessment (B criteria BCF ≥ 2,000; vB criteria: BCF ≥5,000).