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Ecotoxicological information

Short-term toxicity to fish

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Administrative data

Endpoint:
short-term toxicity to fish
Type of information:
(Q)SAR
Adequacy of study:
weight of evidence
Study period:
November 2015
Reliability:
2 (reliable with restrictions)
Justification for type of information:
QSAR prediction: migrated from IUCLID 5.6

Data source

Referenceopen allclose all

Reference Type:
other: QMRF
Title:
Unnamed
Year:
2015
Report date:
2015
Reference Type:
other: QPRF
Title:
Unnamed
Year:
2015
Report date:
2015

Materials and methods

Test guideline
Guideline:
other: REACH guidance on QSARs R.6 May/July 2008
Principles of method if other than guideline:
Model or submodel name: ECOSAR (Anilines (unhindered)) model for acute aquatic toxicity in fish.
Model version: ECOSAR (Ecological Structure Activity Relationships system) (version 1.11).

Test material

Constituent 1
Chemical structure
Reference substance name:
4-chloro-2,6-diaminopyrimidine
EC Number:
205-863-9
EC Name:
4-chloro-2,6-diaminopyrimidine
Cas Number:
156-83-2
Molecular formula:
C4H5ClN4
IUPAC Name:
6-chloropyrimidine-2,4-diamine
Details on test material:
SMILES: Clc1cc(N)nc(N)n1
InChI: InChI=1S/C4H5ClN4/c5-2-1-3(6)9-4(7)8-2/h1H,(H4,6,7,8,9)

Results and discussion

Effect concentrations
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
956.5 mg/L

Any other information on results incl. tables

Sublethal observations / clinical signs:

Endpoint: Short-term toxicity to fish

Dependent variable: Acute toxicity as LC50, i.e. the chemical concentration

(measured in milligrams per liter) that is expected to kill 50% of a group of

organisms (i.e., fish) after an exposure of 96h.

Descriptor values: LogKow = -0.39 (LogKow value estimated by EPI Suite/KOWWIN estimation model)

Domains: ECOSAR predictions are not supported by a specific parameter for the assessment of their reliability and models applicability domain. However, it is assumed that the prediction is less accurate for compounds outside the descriptor (i.e., LogKow) range and molecular weight (MW) range of the training set compounds (training set LogKow range=-0.9/6.0; training set MW range =93/498). Additionally, a LogKow cut-off of 6.0 and a maximum MW of 1000 are defined for the applicability of the ECOSAR predicting acute effects in fish.

Above the LogKow cut-off, data generally indicate that the hydrophobicity of the molecules leads to “no effects at saturation”.

i. descriptor domain: The target compound 6-chloropyrimidine-2,4 -diamine is included in the MW and LogKow ranges, being characterised by a MW equal to 144.5 and a predicted LogKow equal to -0.39.

ii. structural fragment domain: not applicable.

iii. mechanism domain: not applicable.

iv. metabolic domain, if relevant: not applicable.

Structural analogues: No structural analogues are provided by the estimation tool.

The uncertainty of the prediction ECOSAR predictions are not supported by a specific parameter for the assessment of

their uncertainty. However, it is assumed that the prediction is less accurate for compounds outside the descriptor (i.e., LogKow) range and molecular weight (MW) range of the training set compounds (training set LogKow range=-0.9/6.0; training set MW range = 93/498). Additionally, a LogKow cut-off of 6.0 and a maximum MW of 1000 are defined for the applicability of the ECOSAR predicting acute effects in fish. Above the LogKow cut-off, data generally indicate that the hydrophobicity of the molecules leads to “no effects at saturation”. The target compound 6-chloropyrimidine-2,4-diamine is included in the MW and LogKow range, thus falling within the applicability domain of the QSAR model. Overall, the prediction was assessed as moderate reliable.

Applicant's summary and conclusion

Conclusions:
ECOSAR predicted for 6-chloropyrimidine-2,4-diamine an acute LC50 to fish equal to 956.5 mg/L. The prediction is considered moderate reliable.
Executive summary:

Regulatory purpose: This study was designed to generate estimated in silico (nontesting) data for acute aquatic toxicity in fish for 6-chloropyrimidine-2,4-diamine to be used in the regulatory framework of REACH.

Approach for regulatory interpretation of the model result: ECOSAR predicted for 6-chloropyrimidine-2,4-diamine an acute LC50 to fish equal to 956.5 mg/L. The prediction is considered moderate reliable.