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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Reference
Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
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:
Please refer to QMRF and QPRF in the section "Attached justification"
Qualifier:
according to guideline
Guideline:
other: REACH guidance on QSAR R.6
Principles of method if other than guideline:
ECOSAR v1.11: Estimation of acute and chronic toxicity to green algae for chemical class "Esters" and "Neutral Organic SAR (Baseline Toxicity)"
GLP compliance:
not specified
Remarks:
Not applicable for QSAR estimation
Specific details on test material used for the study:
SMILES: O=C(OCC(CCCC)CC)C=CC(=O)O
Test organisms (species):
other: green algae
Water media type:
freshwater
Total exposure duration:
96 h
Key result
Duration:
96 h
Dose descriptor:
EC50
Effect conc.:
6.748 mg/L
Nominal / measured:
estimated
Conc. based on:
test mat.
Basis for effect:
not specified
Remarks on result:
other: ECOSAR class: "Esters-acids"; Substance within applicability domain of the model.
Key result
Dose descriptor:
other: Chronic value
Effect conc.:
3.639 mg/L
Nominal / measured:
estimated
Conc. based on:
test mat.
Basis for effect:
not specified
Remarks on result:
other: ECOSAR class: "Esters-acids"; Substance within applicability domain of the model.

ECOSAR Program (v1.11) Results:

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ECOSAR Version 1.11 Results Page

 

SMILES : O=C(OCC(CCCC)CC)C=CC(=O)O

CHEM  : 2-Butenedioic acid (Z)-, mono(2-ethylhexyl) ester

MOL FOR: C12 H20 O4

MOL WT : 228.29

 

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ECOSAR v1.11 Class-specific Estimations

 

Esters-acid

Predicted

ECOSAR Class                

Organism

Duration

End Pt

mg/L (ppm)

Esters-acid

Green Algae        

96-hr

EC50

6.748

Esters-acid

Green Algae        

 

ChV

3.639

 

Note: * = asterisk designates: Chemical may not be soluble enough to measure this predicted effect. If the effect level exceeds the water solubility by 10X, typically no effects at saturation (NES) are reported.

Conclusions:
Using ECOSAR v1.11 the acute EC50 value for alage was calculated to be 6.748 mg/L. The chronic toxicity for algae was calculated to be 3.639 mg/L.
The substance is within the applicability domain of the model.
Executive summary:

The acute and chronic toxicity in alage were calculated using ECOSAR v 1.11 as part of EPISuite v4.11 from US Environmental Protection Agency.

The adequacy of a prediction depends on the following conditions:

a) the (Q)SAR model is scientifically valid: the scientific validity is established according to the OECD principles for (Q)SAR validation;

b) the (Q)SAR model is applicable to the query chemical: a (Q)SAR is applicable if the query chemical falls within the defined applicability domain of the model;

c) the (Q)SAR result is reliable: a valid (Q)SAR that is applied to a chemical falling within its applicability domain provides a reliable result;

d) the (Q)SAR model is relevant for the regulatory purpose.

 

For assessment and justification of these 4 requirements the QMRF and QPRF files were developed and attached to this study record.

 

Description of the prediction Model

The prediction model was descriped using the harmonised template for summarising and reporting key information on (Q)SAR models. For more details please refer to the attached QSAR Model Reporting Format (QMRF) file. 

 

Assessment of estimation domain

The assessment of the estimation domain was documented in the QSAR Prediction Reporting Format file (QPRF). Please refer to the attached document for the details of the prediction and the assessment of the estimation domain.

Description of key information

Using ECOSAR v1.11 the acute EC50 value for algae was calculated to be 6.748 mg/L. The chronic toxicity for algae was calculated to be 3.639 mg/L. The substance is within the applicability domain of the model.

Key value for chemical safety assessment

EC50 for freshwater algae:
6.748 mg/L
EC10 or NOEC for freshwater algae:
3.639 mg/L

Additional information

The toxicity to aquatic algae of the test substance was calculated using ECOSAR v.1.11 as part of EPISuite v4.11 from US Environmental Protection Agency. Using ECOSAR v1.11 the acute EC50 value for algae was calculated to be 6.748 mg/L. The chronic toxicity for algae was calculated to be 3.639 mg/L. The substance is within the applicability domain of the model.

A dissiminated dossier for the characteristically similar substance, butyl hydrogen maleate (CAS 925-21-3) is available on the ECHA homepage. Based on the QSAR Toolbox (version 4.2) similarity options, both substances share a high degree of similarity with a similarity value of 78.57%.
For butyl hydrogen maleate a 72-h Growth Inhibition test with Pseudokirchneriella subcapitata according to OECD guideline 201 is available. In this algae test an EC50 and a NOEC based on growth rate of 31 mg/L and 25 mg/L were determined, respectively.
The determined acute EC50 value and the chronic value estimated with ECOSAR v.1.11 for the test substance, 2-ethylhexyl hydrogen maleate, are much lower than the study results for butyl hydrogen maleate. Since both substances share a similar structure, similar ecotoxicological properties are suspected. Thus, the QSAR result is considered as a worst case approach.