Essential oil of Petitgrain obtained from the leaves and twigs of Citrus aurantium (Rutaceae) by distillation

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

Not relevant

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:

Petitgrain oil - citrus aurantum is an UVCB substance. Regarding the different solubility of its constituents that make the testing difficult and a known fraction >90%, calculation from the ecotoxicity of the known constituent appears as an acceptable approach.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Principles of method if other than guideline:

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.

GLP compliance:

no

Remarks:

Not required for a calculation based on multiple QSARs method.

Test material

Test material information

Constituent 1

Reference substance name:

Essential oil of Petitgrain obtained from the leaves and twigs of Citrus aurantium (Rutaceae) by distillation

EC Number:

946-433-7

Cas Number:

Not available

Molecular formula:

Not applicable for a natural complex substance (UVCB)

IUPAC Name:

Essential oil of Petitgrain obtained from the leaves and twigs of Citrus aurantium (Rutaceae) by distillation

Test material form:

other: not applicable for in silico study

Details on test material:

- Name of test material (as cited in study report): Petitgrain oil
- Commercially available test material - not applicable for in silico study

Specific details on test material used for the study:

All the constituents with a concentration above 1% were taken into account to describe "typical" and "worst-case" compositions. The worst-case” composition was calculated by using the maximum concentration – instead of the typical concentration – for the more predicted ecotoxic constituents (ErC50≤1mg/l), and the concentrations of the other constituents corrected in order to achieve a 100% mixture. For the prediction, only the constituents which concentration is above 1% are taken into account.

constituents mass fraction (%) within typical composition mass fraction (%) within “worst-case” composition
linalyl acetate 48.00 38.40
linalool 25.00 20.00
geraniol 3.00 2.40
α-terpineol 5.50 4.40
geranyl acetate 4.40 3.20
limonene 1.00 4.00
myrcene 2.50 4.00
β-ocimene 3.50 2.80
nerol 1.00 0.80
neryl acetate 2.00 1.60
β-pinene 1.00 3.00
α-terpinyl acetate 1.00 3.00
β-caryophyllene 1.00 3.00
α-pinene - 3.00
sabinene - 3.00
terpinolene - 3.00
TOTAL 98.50 96.60

Sampling and analysis

Analytical monitoring:

no

Remarks:

Not relevant for a calculation based on multiple QSARs method.

Details on sampling:

Not relevant for a calculation based on multiple QSARs method.

Test organisms

Test organisms (species):

Daphnia sp.

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

48 h

Dose descriptor:

EL50

Remarks:

EL50 WAF

Effect conc.:

10 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr. (dissolved fraction)

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.

Effect concentrations 2

Key result

Duration:

48 h

Dose descriptor:

EL50

Remarks:

EL50 WAF

Effect conc.:

7.5 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr. (dissolved fraction)

Remarks:

Worst-case composition.

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.

Any other information on results incl. tables

"Adapted water solubility" (solubility of the constituent * molar fraction * UNIFAC-approach activity coefficient), lead to concentrations in WAF as follows:

constituents              for the typical composition              for the “worstcase” composition

linalyl acetate                     4.92                                                        2.88

linalool                              2.56                                                       1.50

geraniol                            0.31                                                        0.18

α-terpineol                        0.56                                                        0.33

geranyl acetate                  0.41                                                        0.24

limonene                           0.10                                                        0.30

myrcene                           0.15                                                        0.21

β-ocimene                        0.20                                                        0.14

nerol                                0.10                                                         0.06

neryl acetate                    0.20                                                          0.12

β-pinene                         0.10                                                           0.22

α-terpinyl acetate            0.10                                                           0.22

β-caryophyllene              0.00                                                           0.00

α-pinene                            -                                                              0.17

sabinene                            -                                                              0.22

terpinolene                        -                                                               0.22

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

QSAR model validated to be compliant with the OECD recommendations for QSAR modeling (OECD, 2004).

Conclusions:

For a typical composition, EL50 (mg test item.L-1) = 10 mg/l
For a "worst-case" composition, EL50 (mg test item.L-1) = 7.5 mg/l

Executive summary:

By using a "known constituents approach" based on non-polar-narcosis MOA-1 QSARs and WAF "adapted water solubilities”, the Daphnia 48h-EL50 for a “worst-case composition” is estimated 7.5 mg/l.