Thuya plicata, ext.

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Remarks:

Classification based on calculation rules for mixtures of the CLP Regulation.

Type of information:

calculation (if not (Q)SAR)

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

accepted calculation method

Justification for type of information:

Classification based on calculation rules for mixtures of the CLP Regulation, based on constituents approach of the UVCB substance.
There is no experimental study reference.
Data are compiled on 8 major components which represent about 91% of the UVCB.

Data source

Reference

Reference Type:

publication

Title:

ECOSAR v1.11

Author:

EPA United States Environnement Protection Agency

Year:

2012

Bibliographic source:

https://www.epa.gov/tsca-screening-tools/ecological-structure-activity-relationships-ecosar-predictive-model

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: ECOSAR

Version / remarks:

1.11

Principles of method if other than guideline:

ECOSAR

Test material

Test material information

Constituent 1

Reference substance name:

Thuya plicata, ext.

EC Number:

305-105-8

EC Name:

Thuya plicata, ext.

Cas Number:

94334-32-4

Molecular formula:

not relevant as a UVCB substance

IUPAC Name:

Water steam distillation of needles and twigs of Thuya plicata

Test material form:

liquid

Results and discussion

Effect concentrations

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

1.03 mg/L

Details on results:

The toxicity to daphnia were estimated using the following additivity formulas, as recommended in the Regulation (EC) No 1272/2008 (CLP) section 4.1.3.5.2:
∑ Ci / L(E)C50m = ∑ (Ci / L(E)C50i)
Where,Ci = concentration of component i (weight percentage);
L(E)C50i = LC50 or EC50 for component i, in mg/L; L(E)C50m = L(E)C50 of the part of the mixture with test data.

Applicant's summary and conclusion

Validity criteria fulfilled:

not applicable

Conclusions:

Based on a weight of evidence approach, the toxicity of assessed substance to daphnia during 48 hours can be estimated using adequate toxicity data of major constituents, greater than 1% in the mixture.
These 8 major constituents were considered, representing about 91% of the mixture.
These data are summarized in the above table.
The toxicity to daphnia were estimated using the following additivity formulas, as recommended in the Regulation (EC) No 1272/2008 (CLP) section 4.1.3.5.2:
∑ Ci / L(E)C50m = ∑ (Ci / L(E)C50i)
Where,Ci = concentration of component i (weight percentage);
L(E)C50i = LC50 or EC50 for component i, in mg/L; L(E)C50m = L(E)C50 of the part of the mixture with test data.
Based on data presented above, the EC50 value 48 hours for UVCB substance is calculated at 1.03 mg/L for daphnia.

Executive summary:

With a LC50 daphnia value of 1.03 mg/l and some constituents (terpinene, myrcene, pinene, sabinene and limonene) with logKow > 4, the substance is classified H411 (cat 2) according to table 4.1.0 of regulation 1272/2008 (CLP).