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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:
(Q)SAR
Adequacy of study:
weight of evidence
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 limited documentation / justification
Justification for type of information:
Data is from OECD QSAR toolbox version 3.4 and the QMRF report has been attached.
Qualifier:
according to guideline
Guideline:
other: Estimated data
Principles of method if other than guideline:
Prediction was done using the OECD QSAR toolbox version 3.4.
GLP compliance:
not specified
Specific details on test material used for the study:
- Name of test material (IUPAC name): (2E)-3,7-dimethylocta-2,6-dien-1-yl propanoate
- Common name: Geranyl propionate
- Molecular formula: C13H22O2
- Molecular weight: 210. 3148 g/mol
- Smiles notation: CCC(=O)OC\C=C(/C)\CCC=C(C)C
- InChl: 1S/C13H22O2/c1-5-13(14)15-10-9-12(4)8-6-7-11(2)3/h7,9H,5-6,8,10H2,1-4H3/b12-9+
- Substance type: Organic
- Physical state: Liquid
Analytical monitoring:
not specified
Vehicle:
not specified
Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Test type:
static
Water media type:
freshwater
Total exposure duration:
72 h
Reference substance (positive control):
not specified
Key result
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
1.927 mg/L
Nominal / measured:
estimated
Conc. based on:
not specified
Basis for effect:
growth rate
Remarks on result:
other: Other details not known
Details on results:
The EC50 was 1.92 mg/l

The prediction was based on dataset comprised from the following descriptors: EC50
Estimation method: Takes average value from the 5 nearest neighbours
Domain  logical expression:Result: In Domain

(((((("a" and "b" and "c" and "d" )  and ("e" and ( not "f") )  )  and "g" )  and ("h" and ( not "i") )  )  and "j" )  and ("k" and "l" )  )

Domain logical expression index: "a"

Referential boundary: The target chemical should be classified as Esters (Acute toxicity) by US-EPA New Chemical Categories

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as SN2 AND SN2 >> SN2 Reaction at a sp3 carbon atom AND SN2 >> SN2 Reaction at a sp3 carbon atom >> Activated alkyl esters and thioesters  by Protein binding by OASIS v1.4

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as SN2 AND SN2 >> SN2 reaction at sp3 carbon atom AND SN2 >> SN2 reaction at sp3 carbon atom >> Allyl acetates and related chemicals by Protein binding by OECD

Domain logical expression index: "d"

Referential boundary: The target chemical should be classified as Esters AND Vinyl/Allyl Esters by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "e"

Referential boundary: The target chemical should be classified as Non binder, non cyclic structure by Estrogen Receptor Binding

Domain logical expression index: "f"

Referential boundary: The target chemical should be classified as Strong binder, NH2 group by Estrogen Receptor Binding

Domain logical expression index: "g"

Referential boundary: The target chemical should be classified as Reactive unspecified by Acute aquatic toxicity MOA by OASIS ONLY

Domain logical expression index: "h"

Referential boundary: The target chemical should be classified as -C=CH  [alkenyl hydrogen] AND -CH2-  [linear] AND Ester   [-C(=O)-O-C] AND Methyl  [-CH3] by Bioaccumulation - metabolism alerts

Domain logical expression index: "i"

Referential boundary: The target chemical should be classified as -CH -  [cyclic] by Bioaccumulation - metabolism alerts

Domain logical expression index: "j"

Similarity boundary:Target: CCC(=O)OCC=C(C)CCC=C(C)C
Threshold=80%,
Dice(Atom centered fragments)
Atom type; Count H attached; Hybridization

Domain logical expression index: "k"

Parametric boundary:The target chemical should have a value of Molecular weight which is >= 125 Da

Domain logical expression index: "l"

Parametric boundary:The target chemical should have a value of Molecular weight which is <= 246 Da

Validity criteria fulfilled:
not specified
Conclusions:
Based ion the growth rate inhibition, EC50 value was estimated to be 1.92 mg/l for Species Pseudokirchneriella subcapitata for 72 hrs duration when exposed to (2E)-3,7-dimethylocta-2,6-dien-1-yl propanoate (Geranyl propionate).
Executive summary:

Based on the prediction done using the OECD QSAR toolbox version 3.4 with log kow as the primary descriptor and considering the five closest read across substances, the toxicity on Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum) was predicted for Target substance (2E)-3,7-dimethylocta-2,6-dien-1-yl propanoate (105-90-8). EC50 value was estimated to be 1.92 mg/l for Species Pseudokirchneriella subcapitata for 72 hrs duration when exposed to (2E)-3,7-dimethylocta-2,6-dien-1-yl propanoate (Geranyl propionate). Based on the EC50 value, it can be concluded that the chemical was toxic and can be consider to be classified in aquatic chronic 2 category, but the chemical was readily biodegradable in water.

Based on this ready biodegradability of chemical it can be concluded that the substance (2E)-3,7-dimethylocta-2,6-dien-1-yl propanoateis considered as nontoxic to aquatic environment as per the criteria mentioned in CLP regulation. 

Description of key information

Based on the prediction done using the OECD QSAR toolbox version 3.4 with log kow as the primary descriptor and considering the five closest read across substances, the toxicity on Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum) was predicted for Target substance (2E)-3,7-dimethylocta-2,6-dien-1-yl propanoate (105-90-8). EC50 value was estimated to be 1.92 mg/l for Species Pseudokirchneriella subcapitata for 72 hrs duration when exposed to (2E)-3,7-dimethylocta-2,6-dien-1-yl propanoate (Geranyl propionate). Based on the EC50 value, it can be concluded that the chemical was toxic and can be consider to be classified in aquatic chronic 2 category, but the chemical was readily biodegradable in water. Based on this ready biodegradability of chemical it can be concluded that the substance (2E)-3,7-dimethylocta-2,6-dien-1-yl propanoateis considered as nontoxic to aquatic environment as per the criteria mentioned in CLP regulation. 

Key value for chemical safety assessment

EC50 for freshwater algae:
1.92 mg/L

Additional information

Various predicted data for the target compound (2E)-3,7-dimethylocta-2,6-dien-1-yl propanoate; Geranyl propionate (105-90-8) and supporting weight of evidence studies for its closest read across substance with log Kow as the primary descriptor were reviewed for the toxicity on the algae end point which are summarized as below: 

 

In a prediction done by SSS (2017), using the OECD QSAR toolbox version 3.4 with log kow as the primary descriptor and considering the five closest read across substances, the toxicity on Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum) was predicted for Target substance (2E)-3,7-dimethylocta-2,6-dien-1-yl propanoate (105-90-8). EC50 value was estimated to be 1.92 mg/l for Species Pseudokirchneriella subcapitata for 72 hrs duration when exposed to (2E)-3,7-dimethylocta-2,6-dien-1-yl propanoate (Geranyl propionate). Based on the EC50 value, it can be concluded that the chemical was toxic and can be consider to be classified in aquatic chronic 2 category, but the chemical was readily biodegradable in water. Based on this ready biodegradability of chemical it can be concluded that the substance (2E)-3,7-dimethylocta-2,6-dien-1-yl propanoateis considered as nontoxic to aquatic environment as per the criteria mentioned in CLP regulation. 

Similarly in a supporting weight of evidence study from ABITEC report 2016 for read across chemical 3,7-dimethylocta-2,6-dien-1-yl butyrate, Geranyl butyrate (106-29-6) toxicity experiment was conducted for evaluating the effect of read across substance. Freshwater algal growth inhibition test was carried out on Desmodesmus subspicatus with the substance 3,7-dimethylocta-2,6-dien-1-yl butyrate, Geranyl butyrate according to OECD Guideline 201. The test substance was dissolved in acetone and tested at the concentrations 0, 0, 33, 50, 75, 113, 170 mg/L. Effects on the growth rate of the organism were studied. The median effective concentration (ErC50) for the test substance, 3,7-dimethylocta-2,6-dien-1-yl butyrate in Desmodesmus subspicatus was determined to be 100.3 mg/L. This value indicates that the substance is likely to be non-hazardous to aquatic algae and cannot be classified as toxic as per the CLP criteria.

 

In the third weight of evidence study for the RA chemical (97-64-3) ECOTOX toxicity was studied. Determination of short term toxicity of chemical ethyl (2R)-2-hydroxypropanoate on the growth of aquatic green algae. Test was performed in the static system for 72-96 hrs. 10000 cells /ml total biomass concentration of algal cells was taken in the study. After the exposure of chemical, effect concentration was measured on the basis of inhibition of biomass rate. Based on the inhibition of biomass rate of green algae (Pseudokirchneriella Subcapitata) due to the exposure of chemical ethyl (2R)-2-hydroxypropanoate, the EC50 was 2300 mg/l. Based on the EC50, it was concluded that the chemical was nontoxic and can be consider to be no classified as toxic as per the CLP classification criteria.

 

On the basis of above results for target chemical (2E)-3,7-dimethylocta-2,6-dien-1-yl propanoate; Geranyl propionate (105-90-8) (from OECD QSAR toolbox version 3.4, 2017) and for its read across substance from ABITEC report, secondary sources and authoritative database, it can be concluded that the test substance (2E)-3,7-dimethylocta-2,6-dien-1-yl propanoate (Geranyl propionate) is not toxic and can be consider to be not classified as toxic as per the CLP classification criteria.