Disodium 3,3'-dithiobis[propanesulphonate]

Bioaccumulation: aquatic / sediment

Administrative data

Endpoint:

bioaccumulation: aquatic / sediment

Type of information:

(Q)SAR

Adequacy of study:

supporting study

Study period:

2012

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:

Scientifically acceptable calculation method

Justification for type of information:

1. SOFTWARE
EPIWIN software by US-EPA

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

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
S(=O)(=O)([O-])CCCSSCCCS(=O)(=O)[O-].[Na+].[Na+]

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
- The model and the training and validation sets are published by US Environmental Protection Agency (USA).
The Arnot-Gobas model estimates steady-state bioconcentration factor (BCF; L/kg) and bioaccumulation factor (BAF; L/kg) values for non-ionic organic chemicals in three general trophic levels of fish (i.e., lower, middle and upper) in temperate environments. The model calculations represent general trophic levels (i.e., not for a particular fish species) and are derived for “representative” environmental conditions (e.g., dissolved and particulate organic carbon content in the water column, water temperature). Thus, it provides general estimates for these conditions in absence of site-specific measurements or estimates. The default temperature for the BCF and BAF calculations is 10°C (temperate regions); therefore, the model predictions are not recommended for arctic, sub-tropical or tropical regions or for comparisons with other vastly different conditions (e.g., laboratory tests at ~25°C).
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 BCFBAF Program updates the BCF estimation methodology of the BCFWIN program by using an updated and better evaluated BCF database for selecting training and validation datasets. The exact same regression methodology used to derive the original BCFWIN method was used to derive the BCFBAF method for estimating BCF.

5. APPLICABILITY DOMAIN
The minimum and maximum values for molecular weight and logKow are listed below. Currently there is no universally accepted definition of model domain. However, users may wish to consider the possibility that bioconcentration factor estimates are less accurate for compounds outside the MW and logKow ranges of the training set compounds, and/or that have more instances of a given correction factor than the maximum for all training set compounds. It is also possible that a compound may have a functional group(s) or other structural features not represented in the training set, and for which no fragment coefficient was developed; and that a compound has none of the fragments in the model’s fragment library. In the latter case, predictions are based on molecular weight alone. These points should be taken into consideration when interpreting model results.
Training Set (527 Compounds):
Molecular Weight:
Minimum MW: 68.08 (Furan)
Maximum MW: 991.80 Ionic: (2,7-Naphthalenedisulfonic acid, 4-amino-5-hydroxy-3,6- bis[[4-[[2-(sulfooxy)ethyl]sulfonyl]phenyl]azo]-, tetrasodium salt)
Maximum MW: 959.17 Non-Ionic: (Benzene, 1,1 -oxybis[2,3,4,5,6-pentabromo-)
Average MW: 244.00
Log Kow:
Minimum LogKow: -6.50 Ionic: (2,7-Naphthalenedisulfonic acid, 4-amino-5-hydroxy-3,6-bis[[4-[[2-(sulfooxy)ethyl]sulfonyl]phenyl]azo]-, tetrasodium salt)
Minimum LogKow: -1.37 Non-Ionic: (1,3,5-Triazine-2,4,6-triamine)
Maximum LogKow: 11.26 (Benzenamine, ar-octyl-N-(octylphenyl)-)
Model predictions may be highly uncertain for chemicals that have estimated log KOW values > 9. The model is not recommended at this time for chemicals that appreciably ionize, for pigments and dyes, or for perfluorinated substances.

6. ADEQUACY OF THE RESULT
The organic substance 1-Propanesulfonic acid, 3,3 -dithiobis-, disodium salt lies within the applicability domain with a molecular weight of 354.38 g/mol and a logPow of -3.86. The result seems reasonable taking into account the structure of the substance and its water solubility. Due to the magnitude of the result and the suitable training set the result is considered as adequate.

Data source

Reference

Reference Type:

other:

Title:

EPI Suite Version 4.10

Year:

2012

Bibliographic source:

BCFBAF - Meylan et al. (1997/1999)

Materials and methods

Test guideline

Guideline:

other: REACH guidance on QSARs Chapter R.6 , May 2008

Principles of method if other than guideline:

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). Two different models are used: Regression-based estimate (Traditional method) and Arnot-Gobas method, which is based on the mechanistic first principles.
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

Reference substance name:

Disodium 3,3'-dithiobis[propanesulphonate]

EC Number:

248-324-3

EC Name:

Disodium 3,3'-dithiobis[propanesulphonate]

Cas Number:

27206-35-5

Molecular formula:

C6H14O6S4.2Na

IUPAC Name:

disodium 3,3'-disulfanediyldipropane-1-sulfonate

Details on test material:

SMILES O=S(CCCSSCCCS(=O)(=O)[O-])(=O)[O-].[Na+].[Na+]

Sampling and analysis

Details on sampling:

not applicable

Test solutions

Details on preparation of test solutions, spiked fish food or sediment:

not applicable

Test organisms

Test organisms (species):

other: Fish, not further specified

Details on test organisms:

No further details on test organisms are available.

Study design

Route of exposure:

other: estimated value

Test type:

other: QSAR

Water / sediment media type:

natural water: freshwater

Test conditions

Hardness:

No details available.

Test temperature:

No details available.

pH:

No details available.

Dissolved oxygen:

No details available.

TOC:

No details available.

Salinity:

No details available.

Details on test conditions:

No details available.

Nominal and measured concentrations:

No details available.

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:

3.16 L/kg

Basis:

whole body w.w.

Remarks on result:

other: Regression-based estimate

Bioaccumulation factor 2

Type:

BCF

Value:

0.893 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.

Details on results:

--------------------------------- BCFBAF v3.01 --------------------------------
Summary Results:
Log BCF (regression-based estimate): 0.50 (BCF = 3.16 L/kg wet-wt)
Biotransformation Half-Life (days) : 0.00048 (normalized to 10 g fish)
Log BAF (Arnot-Gobas upper trophic): -0.05 (BAF = 0.893 L/kg wet-wt)

Biotransformation Rate Constant:
kM (Rate Constant): 125 /day (10 gram fish) **
kM (Rate Constant): 70.29 /day (100 gram fish) **
kM (Rate Constant): 39.53 /day (1 kg fish) **
kM (Rate Constant): 22.23 /day (10 kg fish) **
** Predicted value exceeds theoretical whole body maximum value.
kM (Rate Constant) of 125 /day is recommended/applied for 10 g fish

Arnot-Gobas BCF & BAF Methods (including biotransformation rate estimates):
Estimated Log BCF (upper trophic) = -0.049 (BCF = 0.893 L/kg wet-wt)
Estimated Log BAF (upper trophic) = -0.049 (BAF = 0.893 L/kg wet-wt)
Estimated Log BCF (mid trophic) = -0.031 (BCF = 0.9315 L/kg wet-wt)
Estimated Log BAF (mid trophic) = -0.031 (BAF = 0.9315 L/kg wet-wt)
Estimated Log BCF (lower trophic) = -0.027 (BCF = 0.9402 L/kg wet-wt)
Estimated Log BAF (lower trophic) = -0.027 (BAF = 0.9402 L/kg wet-wt)

Arnot-Gobas BCF & BAF Methods (assuming a biotransformation rate of zero):
Estimated Log BCF (upper trophic) = -0.049 (BCF = 0.893 L/kg wet-wt)
Estimated Log BAF (upper trophic) = -0.049 (BAF = 0.893 L/kg wet-wt)

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.

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 3.16 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 0.893 L/kg wet-wt. The whole body primary biotransformation rate estimate for fish gives a half-life of 0.0048 days, whereby the rate constant (kM) for 10 g fish is designated as 125/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 0.9402 L/kg wet-wt is calculated, whereas for the mid trophic level the BCF will result in 0.9315 L/kg wet-wt and the higher trophic level gives a value of 0.893 L/kg wet-wt.