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Ecotoxicological information

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

Reference
Name:
Unnamed
Type:
Constituent
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 concentrationsopen allclose all
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.
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.