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Ecotoxicological information

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:
19 April 2018 - 19 April 2018
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:
Himalayan Cedarwood oil is an UVCB substance. Regarding the different solubility of its constituents that make the testing difficult and a known fraction of 91.57%, calculation from the ecotoxicity of the known constituent appears as an acceptable approach.
Principles of method if other than guideline:
A calculation method prediction was performed to assess the acute toxicity to Daphnia magna of the test item Himalayan Cedarwood oil, a Natural Complex Substance, using the WAF method. This calculation method predicts the endpoint value which would be expected when testing the substance under experimental conditions in a laboratory following the Guideline for Testing of Chemicals No. 202, "Daphnia sp., Acute Immobilisation Test" (1), referenced as Method C.2 of Commission Regulation No. 440/2008 (2) adapted for testing of a mixture using the WAF method. The criterion predicted was the median effective loading rate of the mixture EL50 (Median Effect Loading), a statistically derived loading rate which is expected to cause immobility in 50% of test animals within a period of 48 hours.The acute toxicity to the daphnids was determined using a calculation method for the Mechanism of Action (MechoA) in question (MechoA 1, i.e. narcosis) (3). This method has previously been validated in an internal publication for acute exposure of non-polar narcosis compounds (Bicherel and Thomas, 2014) (4). The algorithm is based on a QSAR model which has been validated to be compliant with the OECD recommendations for QSAR modeling (OECD, 2004; OECD, 2007) (5,6. The QSAR model is based on validated data for a training set of 58 chemicals derived from 48-hour test on daphnids, for which the concentrations of the test item had been determined by chemical analyses over the test period. Further to this the effective loading rate of the WAF is determined by using a series of calculation steps using phase equilibrium thermodynamics and excluding the non-bioavailable fraction, this approach is based on validated data derived from 48-hour EL50 tests on daphnid, for which the concentrations of the test item had been determined by chemical analyses over the test period.

(1) OECD Guideline for testing of chemicals No. 202, "Daphnia sp., Acute Immobilisation Test", adopted April 13, 2004.
(2) Commission Regulation (EC) No. 440/2008, Part C, C.2.: "Daphnia sp. Acute Immobilisation Test", p. 456-463, Official Journal of the European Union (EN), dated May 30, 2008, L 142:1-739.
(3) Bauer, F.J., Thomas, P.C., Fouchard, S.Y., and Neunlist, S.J.M. (2018). A new classification algorithm based on mechanisms of action. Comput. Toxicol. 5, 8–15.
(4) Bicherel P and Thomas PC (2014) iSafeRat® WAF calculation method to predict acute aquatic toxicity. Position paper prepared by KREATiS.
(5) OECD (2004) Principles for the validation for regulatory purposes of (Quantitative) Structure Activity-Relationship Models.
(6) OECD (2007) Guidance document on the validation of (Quantitative)Structure-Activity Relationships [(Q)SAR] models. ENV/JM/MONO(2007)2. Environment Directorate OECD. Paris. Mars 2007.
GLP compliance:
no
Analytical monitoring:
no
Remarks:
Not required for a calculation based on multiple QSARs method.
Details on sampling:
Not relevant
Test organisms (species):
Daphnia sp.
Water media type:
freshwater
Total exposure duration:
48 h
Key result
Duration:
48 h
Dose descriptor:
EL50
Effect conc.:
7.8 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: Calculation based on QSARs
Remarks:
the effective loading rate of the WAF is determined by using a series of calculation steps using phase equilibrium thermodynamics and excluding the non-bioavailable fraction
Validity criteria fulfilled:
not applicable
Remarks:
QSAR model validated to be compliant with the OECD recommendation for QSAR modelling (OECD, 2004) described within the QMRF.
Conclusions:
The 48-hour EL50 of Himalayan Cedarwood oil was concluded 7.8 mg/L.
Executive summary:

A calculation method prediction was performed to assess the acute toxicity to daphnids of the test item Himalayan Cedarwood oil, a Natural Complex Substance, using the WAF method. This calculation method predicts the endpoint value which would be expected when testing the substance under experimental conditions in a laboratory following the Guideline for Testing of Chemicals No. 202, "Daphnia sp., Acute Immobilisation Test", referenced as Method C.2 of Commission Regulation No. 440/2008 adapted for testing of a mixture using the WAF method. The test item falls within the applicability domain of the model and was therefore reliably predicted for its acute toxicity (48h-EL50) to daphnids. By using a "known constituents approach" based on non-polar-narcosis MOA-1 QSARs and WAF "adapted water solubilities”, 48-hour EL50 of Himalayan Cedarwood oil was concluded to be 7.8 mg/L.

Description of key information

A calculation method prediction was performed to assess the acute toxicity to daphnids of the test item Himalayan Cedarwood oil, a Natural Complex Substance, using the WAF method. This calculation method predicts the endpoint value which would be expected when testing the substance under experimental conditions in a laboratory following the Guideline for Testing of Chemicals No. 202, "Daphnia sp., Acute Immobilisation Test", referenced as Method C.2 of Commission Regulation No. 440/2008 adapted for testing of a mixture using the WAF method. The test item falls within the applicability domain of the model and was therefore reliably predicted for its acute toxicity (48h-EL50) to daphnids. By using a "known constituents approach" based on non-polar-narcosis MOA-1 QSARs and WAF "adapted water solubilities”, 48-hour EL50 of Himalayan Cedarwood oil was concluded to be 7.8 mg/L.

Key value for chemical safety assessment

EC50/LC50 for freshwater invertebrates:
7.8 mg/L

Additional information