(1S)-3,7,7-trimethylbicyclo[4.1.0]hept-3-ene

Long-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

From 2019-02-25 to 2019-02-25

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:

Not applicable.

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

reference to same study

Cross-reference 2

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2019

Report date:

2019

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 211 (Daphnia magna Reproduction Test)

Deviations:

yes

Remarks:

QSAR method

Principles of method if other than guideline:

The chronic toxicity of the daphnids was determined using a validated QSAR model for the Mechanism of Action (MechoA) in question (MechoA 1.1, i.e. non-polar narcosis) (Bauer et al., 2018). The QSAR is based on validated data for a training set of 30 chemicals derived from 21-day test on daphnids, for which the concentrations of the test item had been determined by chemical analyses over the test period.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

3,7,7-trimethylbicyclo[4.1.0]hept-3-ene

EC Number:

236-719-3

EC Name:

3,7,7-trimethylbicyclo[4.1.0]hept-3-ene

Cas Number:

13466-78-9

Molecular formula:

C10H16

IUPAC Name:

3,7,7-trimethylbicyclo[4.1.0]hept-3-ene

Test material form:

liquid

Sampling and analysis

Analytical monitoring:

not required

Details on sampling:

Not applicable.

Test solutions

Vehicle:

not specified

Details on test solutions:

Not applicable.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

Not applicable.

Study design

Test type:

other: Preferentially results from a flow-through test were used for regression derivation. However semi-static with daily renewal of test solutions and the control was accepted (preferably accompanied by analytical measurements over the study period)

Water media type:

freshwater

Limit test:

no

Total exposure duration:

21 d

Remarks on exposure duration:

None.

Post exposure observation period:

Not applicable.

Test conditions

Hardness:

Not applicable.

Test temperature:

The temperatures varied from approximately 20 to 23 °C. This small difference is not expected to contribute to the variability of the values found in experimental data.

pH:

Test results were taken from studies with measured pHs between 6 - 9.

Dissolved oxygen:

Not applicable.

Salinity:

Not applicable.

Conductivity:

Not applicable.

Nominal and measured concentrations:

Not applicable.

Details on test conditions:

For suspected volatile substances only results from tests performed in closed vessels were accepted unless accompanying analytical monitoring proved such a design was not necessary.

Reference substance (positive control):

not required

Results and discussion

Effect concentrations

Key result

Duration:

21 d

Dose descriptor:

EC10

Effect conc.:

0.05 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks on result:

other: 95% CL

Remarks:

0.033-0.075

Details on results:

None.

Results with reference substance (positive control):

Not applicable.

Reported statistics and error estimates:

95 % CL [0.033-0.075] QSAR statistical parameters are given in the QMRF and QPRF.

Any other information on results incl. tables

   Evaluation and statistics

The evaluation of the effect was based on regression line derived from a training set of 30chemicals with MechoA 1.1 using a validated dataset on subcooled solubility versus the maximum acceptable toxicant concentration (MATC) based on reproducibility of Daphnia magna following the methodology outlined in ECETOC (2013) and Thomas et al.(2015). In brief, the algorithm used was an updated (improved) version of that used by ECETOC for non-polar narcotic compounds and then validated using an external test set. The modelling algorithm was derived using a simple linear regression with the following general equation:

logEC10 = a X logWater Solubility +b

The correlation coefficient R²and Root Mean Standard Error (RMSE) values for this model were 0.9628 and 0.3203, respectively. As discussed in the QSAR Model Reporting Format, closer the R² is to 1 and lower the RMSE values are, better is the goodness-of-fit for the model. Therefore, the model was considered as reliable for providing accurate predictions falling within its applicability domain. Further statistical evidence of high prediction accuracy are provided in the QSAR Prediction Reporting Format (QPRF) for the substance provided in Annex Iand the QSAR Model Reporting Format (QMRF)(KREATiS, 2019).Other MechoAs are being added to the KREATiS database as sufficient evidence for high accuracy predictions becomes available.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The test item falls within the applicability domain of the model and can therefore be considered a reliably prediction for chronic toxicity (21d-EC10) to daphnids. Therefore, this endpoint value can be considered valid for use in risk assessment and classification and labelling.
The 21d-EC10 of the test item to daphnids was predicted as 0.050 mg/L.
95% confidence interval (α = 0.05): 0.033 – 0.075 mg/L.

Based on the results of this study, delta-3-carene is classified hazardous to the aquatic environment according to Regulation (EC) No 1272/2008 (CLP) - Chronic Category 2.

Executive summary:

A QSAR model was used to calculate the chronic toxicity of test item delta-3 -carene to daphnid. This QSAR model has been validated to be compliant with the OECD recommendations for QSAR modeling (OECD, 2004) and predicts the endpoint value which would be expected when testing the substance under experimental conditions in a laboratory following Guideline for Testing of Chemicals No. 211, "Daphnia magna Reproduction Test" (OECD, 2012). The criterion predicted was the EC10 (10% Effective Concentration), a concentration which isexpected to cause an effect of 10% onreproducibility within a period of 21 days.

The result below is the chronic toxicity value anticipated during to a 21-day EC10 study on daphnids reproducibility.The 21-day EC10 is predicted as follows:

 

Time (d)	EC10 (mg test item.L^-1)	95% confidence limits (mg test item.L^-1)
21	0.050	0.033 – 0.075