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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Reference
Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
calculation (if not (Q)SAR)
Remarks:
Estimated by calculation
Adequacy of study:
key study
Study period:
2017-03-16 to 2017-03-17
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
accepted calculation method
Remarks:
Calculation method is used; calculation method applicable for that endpoint.
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Deviations:
yes
Remarks:
calculation method
Principles of method if other than guideline:
The acute toxicity to aquatic algae was determined using a validated QSAR for the Mode of Action in question. The first step of the iSafeRat mixture toxicity calculation employs phase equilibrium thermodynamics in order to determine the concentrations of each constituent within the WAF. This fraction equates to the analysable fraction of a WAF study.
Within the WAF, the constituents also partition between themselves further reducing the bioavailable fraction and thus the toxicity of the mixture compared to the individual constituents. In the calculation the second step is to remove this non-bioavailable fraction.
The final step is to determine the truly bioavailable fraction of the WAF per constituent. The ErC50s of each constituent are already known from literature or calculated using the iSafeRat QSAR model. Each value and calculation has been included as a supporting study in the IUCLID. An additivity approach (based on Chemical Activity of each constituent) is used in order to calculate the Effective Loading rate of the WAF.
The method has been validated using data derived from 72-hour ErC50 tests on aquatic algae, 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.
GLP compliance:
not specified
Specific details on test material used for the study:
Not applicable
Analytical monitoring:
not required
Details on sampling:
not applicable
Vehicle:
no
Details on test solutions:
not applicable
Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
not applicable
Test type:
other: calculation method
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Remarks on exposure duration:
72h-ErL50 (effective loading rate of WAF)
Post exposure observation period:
not applicable
Hardness:
Hardness is not a necessary component of the WAF calculation
Test temperature:
The Temperature is not a necessary component of the WAF calculation
pH:
The pH is not a necessary component of the WAF calculation
Dissolved oxygen:
The oxygen concentration is not a necessary component of the WAF calculation
Salinity:
Salinity is not a necessary component of the WAF calculation.
Nominal and measured concentrations:
The calculation determines measured concentrations
Details on test conditions:
calculation method
Reference substance (positive control):
not required
Duration:
72 h
Dose descriptor:
other: ErL50
Remarks:
effective loading rate of WAF
Effect conc.:
24 mg/L
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other:
Remarks:
Based on the typical composition of lavandin oil grosso
Duration:
72 h
Dose descriptor:
other: ErL50 / effevtive loading rate of WAF
Effect conc.:
21 mg/L
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: Based on the typical composition of lavandin oil abrial
Duration:
72 h
Dose descriptor:
other: ErL50 / effevtive loading rate of WAF
Effect conc.:
22 mg/L
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: based on the typical composition of lavandin oil super
Duration:
72 h
Dose descriptor:
other: ErL50 / effevtive loading rate of WAF
Effect conc.:
25 mg/L
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: based on the typical composition of lavandin oil sumian
Details on results:
not applicable
Results with reference substance (positive control):
not applicable
Reported statistics and error estimates:
not applicable

At this loading rate, the expected concentrations of each constituent in the mixture (based on thermodynamic calculation) are as follows:

 

concentration in the WAF (mg.L-1)

constituents

GROSSO

ABRIAL

SUPER

SUMIAN

linalool

7.5

7.0

5.7

10

linalyl acetate

7.1

5.1

8.8

4.7

camphor

1.9

1.9

1.0

1.5

cineol 1,8

1.7

2.0

0.88

1.9

terpinene-1-ol 4

0.87

0.19

0.088

0.10

borneol laevo

0.72

0.51

0.51

1.4

lavandulyl acetate

0.62

0.30

0.29

0.049

β-caryophyllene

0.0021

0.0010

0.0020

0.0016

α-terpineol

0.29

0.16

-

0.21

β-farnesene

0.00058

-

0.00040

0.00042

β-ocimene

0.072

0.39

0.22

0.37

limonene

0.11

0.10

-

0.066

myrcene

0.0398

0.032

-

-

octan-3-one

-

-

0.18

-

Validity criteria fulfilled:
yes
Conclusions:
72h-ErL50 for the typical composition of lavandin oil grosso = 24 mg/L
72h-ErL50 for the typical composition of lavandin oil abrial = 21 mg/L
72h-ErL50 for the typical composition of lavandin oil super = 22 mg/L
72h-ErL50 for the typical composition of lavandin oil sumian = 25 mg/L
Executive summary:

Lavandin Oil is a Natural Complex Substance (UVCB) with four different qualities (grosso, abrial, super and sumian) that have well-defined compositions. The acute toxicity of lavandin oil to aquatic algae has been investigated using an in-house calculation method that replaces an OECD 201 study and guideline for Testing of Chemicals No. 23 (i.e. WAF conditions). The typical compositions of the four qualities of the substance have been investigated.

The first step of the iSafeRat mixture toxicity calculation employs phase equilibrium thermodynamics in order to determine the concentrations of each constituent within the WAF. This fraction equates to the analyzable fraction of a WAF study. Within the WAF, the constituents also partition between themselves further reducing the bioavailable fraction and thus the toxicity of the mixture compared to the individual constituents. In the calculation the second step is to remove this non-bioavailable fraction.

The final step is to determine the truly bioavailable fraction of the WAF per constituent. The ErC50s of each constituent are already known from literature or predicted using the iSafeRat QSAR model. Each value has been included as a supporting study in the IUCLID. An additivity approach (based on Chemical Activity of each constituent) is used in order to calculate the Effective Loading rate of the WAF.

The 72h ErL50 of the four qualities of Lavandin oil were 24, 21, 22 and 25 mg test material/L for the typical compositions of lavandin oil grosso, abrial, super and sumian respectively. For that endpoint, the most conservative value is selected for the registered substance lavandin oil and corresponds to a 72h-ErL50 of 21 mg/L.

Based on the results of this study, Lavandin oil would not be classified as acute 1 to aquatic organisms in accordance with the classification of the CLP.

This toxicity study is acceptable and can be used for that endpoint.

 

Results Synopsis

Test Type: Calculation method

48h-EL50: 21 mg test material/L based on typical composition of lavandin oil abrial (most conservative value amongst the four qualities of lavandin oil)

Description of key information

The 72-h ErL50 of the four qualities of Lavandin oil were 24, 21, 22 and 25 mg test material/L for the typical compositions of lavandin oil grosso, abrial, super and sumian respectively. For that endpoint, the most conservative value for the substance lavandin oil is selected and corresponds to a 72h-ErL50 of 21 mg/L.

Based on the results of this study, Lavandin oil would not be classified as acute 1 to aquatic organisms in accordance with the classification of the CLP.

Key value for chemical safety assessment

EC50 for freshwater algae:
21 mg/L

Additional information

For that endpoint, one reliable study was available: an in-house calculation method that replaces an OECD 201 study and guideline for Testing of Chemicals No. 23 (i.e. WAF conditions).The typical compositions of each quality of lavandin oil have been investigated.

The first step of the iSafeRat mixture toxicity calculation employs phase equilibrium thermodynamics in order to determine the concentrations of each constituent within the WAF. This fraction equates to the analyzable fraction of a WAF study. Within the WAF, the constituents also partition between themselves further reducing the bioavailable fraction and thus the toxicity of the mixture compared to the individual constituents. In the calculation the second step is to remove this non-bioavailable fraction.

The final step is to determine the truly bioavailable fraction of the WAF per constituent. The ErC50s of each constituent are already known from literature or predicted using the iSafeRat QSAR model. Each value has been included as a supporting study in the IUCLID. An additivity approach (based on Chemical Activity of each constituent) is used in order to calculate the Effective Loading rate of the WAF.

Based on the results of this study, Lavandin oil would not be classified as acute 1 to aquatic organisms in accordance with the classification of the CLP.

This toxicity study is acceptable and can be used for that endpoint.