Registration Dossier

Administrative data

Endpoint:
bioaccumulation in aquatic species, other
Type of information:
(Q)SAR
Adequacy of study:
weight of evidence
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 limited documentation / justification
Justification for type of information:
1. SOFTWARE
BCFBAF v3.01 (US EPA)

2. MODEL (incl. version number)
Estimation using log Kow (octanol-water partition coefficient)
For Log Kow 1.0 to 7.0 the derived QSAR estimation equation is:

Log BCF = 0.6598 Log Kow - 0.333 + Σ correction factors
(n = 396, r2 = 0.792, Q2 = 0.78, std dev = 0.511, avg dev = 0.395)


3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
C=CCN=C=S

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
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.
The measured BCF values used in the revised regressions were selected from a quality reviewed BCF database (Arnot and Gobas, 2006); details of the data quality review methods are described in Arnot and Gobas (2006). Single BCF values were selected for each compound (median values were generally selected for compounds with multiple values).
Estimation Methodology
The BCFBAF method 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.
Training Dataset Included:
466 Non-Ionic Compounds
61 Ionic Compounds (carboxylic acids, sulfonic acids, quats)

Methodology for Non-Ionic was to separate compounds into three divisions by Log Kow value as follows:
Log Kow < 1.0
Log Kow 1.0 to 7.0
Log Kow > 7.0

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)-)

6. ADEQUACY OF THE RESULT
The estimate value has been generated by a valid model. The model is applicable to Allyl Isothiocyanate
with the necessary level of reliability and is sufficiently relevant for the regulatory purpose.

Data source

Reference
Reference Type:
other: QSAR
Title:
BCF for Allyl Isothiocyanate
Year:
2017
Bibliographic source:
BCFBAF v3.01 (US EPA)

Materials and methods

Principles of method if other than guideline:
- Software tool(s) used including version: BCFBAF v3.01 (US EPA)
- Model(s) used: Estimation using log Kow (octanol-water partition coefficient)
- Model description: see field 'Justification for type of information'
- Justification of QSAR prediction: see field 'Justification for type of information'

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
liquid

Results and discussion

Bioaccumulation factoropen allclose all
Type:
BCF
Value:
7.5 L/kg
Type:
other: Log BCF
Value:
0.874 dimensionless

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
An estimated BCF of 7.5 L/kg was calculated in fish for allyl isothiocyanate, using an experimental log Kow of 1.83 and a regression-derived equation. This BCF suggests the potential for bioconcentration in aquatic organisms is low.