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Short-term toxicity to aquatic invertebrates

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Reference
Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
(Q)SAR
Adequacy of study:
key study
Study period:
2017-06-20
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:
1. SOFTWARE
OECD Toolbox 3.4.0.17
Guideline:
other: REACH Guidance on QSARs R.6
Principles of method if other than guideline:
- Software tool(s) used including version: QSAR-prediction with QSAR Toolbox 3.4.0.17 Database version: 3.8.8/3.1.2
GLP compliance:
no
Specific details on test material used for the study:
SMILES: CCCCCCCCOC(=O)C(C)=C
Test organisms (species):
Daphnia magna
Test type:
other: QSAR predicted value
Key result
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
4.79 mg/L
Nominal / measured:
not specified
Conc. based on:
other: QSAR predicted value
Basis for effect:
mortality
Remarks on result:
other: QSAR predicted value

QSAR TOOLBOX 3.4.0.17 (database version: 3.8.8/3.1.2) predicted that n-octyl methacrylate has an EC50 of 4.79 mg/L( Daphnia magna).

Toxicity of the target chemical is predicted from category members using trend analysis based

on 10 values within the range of 2.57 - 380 mg/L from 10 category members. Category members are single

chemicals or mixtures and are selected based on the profile of the target chemical. Only chemicals having

experimental data are listed in the category.

The target chemical FALLS within applicability domain of the prediction.

The data used for calculating the current prediction is taken from 11 experimental values selected from

the following database(s):

1. ECHA CHEM

Validity criteria fulfilled:
yes
Conclusions:
EC50 (48h) daphnia magna of n-octyl methacrylate predicted by QSAR TOOLBOX 3.4.0.17 database version: 3.8.8/3.1.2 from category trend analysis of 10 category members is 4.79 mg/l.
Executive summary:

QSAR Toolbox prediction based on trend analysis

 

Prediction of EC50 (48h) Daphnia magna for n-octyl methacrylate

 

Summary

Toxicity of the target chemical (4.79 mg/L) is predicted from category members using trend analysis based

on 10 values within the range 2.57 - 380 mg/L from 10 category members. Category members are single

chemicals or mixtures and are selected based on the profile of the target chemical. Only chemicals having

experimental data are listed in the category.

The target chemical FALLS within applicability domain of the prediction. The data used for calculating the current prediction is taken from 11 experimental values selected from

the following database(s):

1. ECHA CHEM

NOTE: Any of data in this dataset are disseminated by the European Union on a right-to-know basis and this is not a publication in the same sense as a book or an article in a journal. The right of ownership in any part of this information is reserved by the data owner(s). The use of this information for any other, e.g. commercial purpose is strictly reserved to the data owners and those persons or legal entities having paid the respective access fee for the intended purpose.

Description of key information

EC50 (48h) Daphnia magna of n-octyl methacrylate predicted by QSAR TOOLBOX 3.4.0.17 database version: 3.8.8/3.1.2 from category trend analysis of 10 category members is 4.79 mg/l (Evonik Oil Additives GmbH, 2017).

Key value for chemical safety assessment

EC50/LC50 for freshwater invertebrates:
4.79 mg/L

Additional information

There is no reliable key study available for n-octyl methacrylate but a valid prediction by QSAR TOOLBOX 3.4.0.17 database version: 3.8.8/3.1.2.

EC50(48h) Daphnia magna of n-octyl methacrylate predicted by QSAR TOOLBOX 3.4.0.17 database version: 3.8.8/3.1.2 from category trend analysis of 10 category members is 4.79 mg/l

(Evonik Oil Additives GmbH, 2017). The experimental data with the structural analogue 2-Ethylhexyl methacrylate are of the same order of magnitude (please see read across to 2 -EHMA) and support the prediction by QSAR TOOLBOX with n-octyl methacrylate.

Read across to 2 -Ethylhexyl methacrylate (2 -EHMA):

Acute toxicity data of the substance 2 -EHMA to daphnia are available from four different test reports, 2 acute guideline studies with Daphnia magna and 48 h toxicity data from two chronic invertebrate studies. The two acute studies have deficiencies because of the use of /solvent/dispersant in order to overcome the limited solubility of the test material. In addition, the two results are not very consistent.

In the first one (MoE 1998) several of the concentrations tested were above the solubility limit in pure water, and the obtained EC50-48h is about 5.6 mg/L. In the second one (Safepharm 1995), a solvent (DMF) was used to help to dissolve the substance in the medium. Although use of solvent is not encouraged, DMF is among those listed in the OECD "Guidance document on aquatic toxicity testing of difficult substances and mixtures" (OECD, 2000). The EC50 -48h in this study was 0.85 mg/L.

As the two results are not very consistent, further information can be drawn from the two chronic studies in order to gain more confidence in the evaluation. In both studies the toxicity of 2-EHMA to the parental Daphnia was monitored. In one reproduction toxicity test (Fraunhofer 2004, see section 6.1.4) there was no toxicity to parental daphnia after 48 h of exposure up to the highest test concentration of 2.75 mg/L. At the same concentration 80 % of the parental daphnids were immobilised after 72h. This is consistent with the results of the other Daphnia reproduction study where no immobilisation was observed after 48 h at 2.2 mg/L (nominal/1.51 mg/L(measured) while 40 % immobilisation of the parental daphnids were observed at 5 mg/L (nominal) /3.82 mg/L(measured). The results of these two tests are consistent and indicate that the 48h-EC50 is more likely in a range between 2 and 3 mg/L. Therefore, the geometric mean of the two acute studies is used as the relevant parameter for the assessment: 2.18 mg/L for 2 -EHMA.

There are no data on the toxicity of 2-EHMA to marine invertebrates, but studies with the common metabolite of the category, methacrylic acid, indicate that marine species are not expected to be more sensitive to methacrylates than freshwater species (Sverdrup, 2001).