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The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

Endpoint:
adult fish: sub(lethal) effects
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:
For the prediction of chronic endpoint values (NOEC) for fish, standard software tools (ECOSAR) are available. However, the predictions are restricted to a few compound classes only, excluding some of the metabolites of diflufenican. Therefore in-house QSARs were developed (six models).

Data source

Reference
Reference Type:
other: QSAR
Title:
Unnamed
Year:
2016
Report date:
2016

Materials and methods

Principles of method if other than guideline:
For the prediction of chronic endpoint values (NOEC) for fish, standard software tools (ECOSAR) are available. However, the predictions are restricted to a few compound classes only, excluding some of the metabolites of diflufenican. Therefore in-house QSARs were developed as described below.
The algorithm chosen for model building is Partial Least Squares (PLS). The QSAR starts from experimentally determined rate constants published in the literature, which are then modeled by a set of calculated descriptors, obtained from standard tools for the generation of such descriptors.
The new QSARs are based on a set of 124 compounds, selected from the PPDB by similarity/diversity considerations.
GLP compliance:
no

Test material

Constituent 1
Chemical structure
Reference substance name:
2,4-difluoroaniline
EC Number:
206-687-5
EC Name:
2,4-difluoroaniline
Cas Number:
367-25-9
Molecular formula:
C6H5F2N
IUPAC Name:
2,4-difluoroaniline

Sampling and analysis

Analytical monitoring:
not required

Test solutions

Vehicle:
no

Test organisms

Test organisms (species):
other: fish

Study design

Test type:
other: not specified
Water media type:
freshwater
Total exposure duration:
21 d

Test conditions

Reference substance (positive control):
not required

Results and discussion

Effect concentrationsopen allclose all
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
0.56 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Remarks on result:
ChV (chronic value, QSAR)
Remarks:
AE 0542291; Model: M121
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
1.45 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Remarks on result:
ChV (chronic value, QSAR)
Remarks:
AE B107137; Model: M121
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
0.23 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Remarks on result:
ChV (chronic value, QSAR)
Remarks:
AE C522392; Model: M121
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
0.02 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Remarks on result:
ChV (chronic value, QSAR)
Remarks:
diflufenican; Model: M121
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
0.89 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Remarks on result:
ChV (chronic value, QSAR)
Remarks:
AE 0542291; Model: M51
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
2.3 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Remarks on result:
ChV (chronic value, QSAR)
Remarks:
AE B107137; Model: M51
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
0.35 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Remarks on result:
ChV (chronic value, QSAR)
Remarks:
AE C522392; Model: M51
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
0.05 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Remarks on result:
ChV (chronic value, QSAR)
Remarks:
diflufenican; Model: M51
Details on results:
Amongst the set of six models described the PLS model M121 (n=124) is the best compromise between statistical performance and simplicity. It uses 9 raw descriptors and shows the second best performance of the models
Looking at the statistical parameters only, model M51 is superior to all the other models. However, not all of its 18 raw descriptors have a clear physical meaning.

Applicant's summary and conclusion

Validity criteria fulfilled:
not applicable
Conclusions:
Amongst the set of six models described in this document the PLS model M121 (n=124) is the best compromise between statistical performance and simplicity. Based on model M121 the predicted chronic fish endpoints (NOEC) for the diflufenican metabolites AE B107137, AE 0542291 and AE C522392 are 0.56, 1.45 and 0.23 mg/L, respectively.