Geranyl isobutyrate

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

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:

The supporting QMRF report has been attached

Qualifier:

according to guideline

Guideline:

other: as mentioned below

Principles of method if other than guideline:

The data is predicted using the OECD QSAR toolbox version 3.3 with logKow as the primary descriptor.

GLP compliance:

not specified

Specific details on test material used for the study:

- Name of test material :3,7-dimethylocta-2,6-dien-1-yl 2-methylpropanoate
- Molecular formula: C14H24O2
- Molecular weight: 224.342 g/mol
- Smiles notation : C(OC\C=C(\CC\C=C(/C)C)C)(C(C)C)=O
- InChl : 1S/C14H24O2/c1-11(2)7-6-8-13(5)9-10-16-14(15)12(3)4/h7,9,12H,6,8,10H2,1-5H3/b13-9+
- Substance type:Organic
- Physical state: Liquid

Analytical monitoring:

not specified

Vehicle:

not specified

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Test type:

static

Water media type:

freshwater

Total exposure duration:

72 h

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

48.552 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

other: Population

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

Domain logical expression index: "a"

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

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as Alkene AND Allyl AND Carboxylic acid ester AND Isopropyl by Organic Functional groups

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as Allyl AND Carboxylic acid ester AND Isopropyl AND Overlapping groups by Organic Functional groups (nested)

Domain logical expression index: "d"

Referential boundary: The target chemical should be classified as Aliphatic Carbon [CH] AND Aliphatic Carbon [-CH2-] AND Aliphatic Carbon [-CH3] AND Carbonyl, aliphatic attach [-C(=O)-] AND Ester, aliphatic attach [-C(=O)O] AND Miscellaneous sulfide (=S) or oxide (=O) AND Olefinic carbon [=CH- or =C<] AND Tertiary Carbon by Organic functional groups (US EPA)

Domain logical expression index: "e"

Referential boundary: The target chemical should be classified as Carbonic acid derivative AND Carboxylic acid derivative AND Carboxylic acid ester by Organic functional groups, Norbert Haider (checkmol)

Domain logical expression index: "f"

Referential boundary: The target chemical should be classified as No superfragment by Superfragments ONLY

Domain logical expression index: "g"

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

Domain logical expression index: "h"

Referential boundary: The target chemical should be classified as Aliphatic Amines OR Benzyl Nitriles OR Halopyrdines OR Pyrazoles/Pyrroles OR Pyrethroids OR Quinones OR Sulfonyl Ureas OR Triazines, Aromatic OR Vinyl/Allyl Halides by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "i"

Referential boundary: The target chemical should be classified as No alert found by Protein binding alerts for Chromosomal aberration by OASIS v1.1

Domain logical expression index: "j"

Referential boundary: The target chemical should be classified as Ac-SN2 OR Ac-SN2 >> Acylation involving an activated (glucuronidated) ester group OR Ac-SN2 >> Acylation involving an activated (glucuronidated) ester group >> Arenecarboxylic Acid Esters OR AN2 OR AN2 >> Nucleophilic addition to pyridonimine tautomer of aminopyridoindoles or aminopyridoimidazoles OR AN2 >> Nucleophilic addition to pyridonimine tautomer of aminopyridoindoles or aminopyridoimidazoles >> Heterocyclic Aromatic Amines OR Radical mechanism OR Radical mechanism >> ROS generation and direct attack of hydroxyl radical to the C8 position of nucleoside base OR Radical mechanism >> ROS generation and direct attack of hydroxyl radical to the C8 position of nucleoside base >> Heterocyclic Aromatic Amines OR SE reaction (CYP450-activated heterocyclic amines) OR SE reaction (CYP450-activated heterocyclic amines) >> Direct attack of arylnitrenium cation to the C8 position of nucleoside base OR SE reaction (CYP450-activated heterocyclic amines) >> Direct attack of arylnitrenium cation to the C8 position of nucleoside base >> Heterocyclic Aromatic Amines OR SR reaction (peroxidase-activated heterocyclic amines) OR SR reaction (peroxidase-activated heterocyclic amines) >> Direct attack of arylnitrenium radical to the C8 position of nucleoside base OR SR reaction (peroxidase-activated heterocyclic amines) >> Direct attack of arylnitrenium radical to the C8 position of nucleoside base >> Heterocyclic Aromatic Amines by Protein binding alerts for Chromosomal aberration by OASIS v1.1

Domain logical expression index: "k"

Parametric boundary:The target chemical should have a value of log Kow which is >= 0.853

Domain logical expression index: "l"

Parametric boundary:The target chemical should have a value of log Kow which is <= 7.53

Validity criteria fulfilled:

not specified

Conclusions:

The median Effective concentration (EC50) value for 3,7-dimethylocta-2,6-dien-1-yl 2-methylpropanoate on Desmodesmus subspicatus in a 72 hour study was estimated to be 48.55 mg/L on the basis of effects on growth rate.

Executive summary:

Based on the prediction done using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the five closest read across substances, the short term toxicity on aquatic algae and cyanobacteria was predicted for target substance 3,7-dimethylocta-2,6-dien-1-yl 2-methyl propanoate (CAS no. 2345 -26 -8). EC50 value was estimated to be 48.55 mg/l for Desmodesmus subspicatus for 72 h duration. Based on this value it can be concluded that the substance 3,7-dimethylocta-2,6-dien-1-yl 2-methylpropanoate is considered to be toxic to aquatic environment. Since the chemical is readily biodegradable in nature, chemical 3,7-dimethylocta-2,6-dien-1-yl 2-methylpropanoate can be considered as non-toxic to aquatic organisms and can be considered to be not classified as per the CLP classification criteria.

 

Description of key information

Based on the prediction done using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the five closest read across substances, the short term toxicity on aquatic algae and cyanobacteria was predicted for target substance 3,7-dimethylocta-2,6-dien-1-yl 2-methyl propanoate (CAS no. 2345 -26 -8) (2017). EC50 value was estimated to be 48.55 mg/l for Desmodesmus subspicatus for 72 h duration. Based on this value it can be concluded that the substance 3,7-dimethylocta-2,6-dien-1-yl 2-methylpropanoate is considered to be toxic to aquatic environment. Since the chemical is readily biodegradable in nature, chemical 3,7-dimethylocta-2,6-dien-1-yl 2-methylpropanoate can be considered as non-toxic to aquatic organisms and can be considered to be not classified as per the CLP classification criteria.

Key value for chemical safety assessment

EC50 for freshwater algae:

48.55 mg/L

Additional information

Predicted data for the target chemical 3,7 -dimethylocta-2,6 -dien-1 -yl 2 -methylpropanoate (CAS No. 2345-26-8) and various weight of evidence study for its read across substance were reviewed to summarize the following information:

 

Short term toxicity on aquatic algae and cyanobacteria of target chemical3,7-dimethylocta-2,6-dien-1-yl 2-methylpropanoate(CAS No. 2345-26-8) is predicted using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the five closest read across substances (2017). EC50 value was estimated to be 48.55 mg/l for Desmodesmus subspicatus for 72 h duration. Based on this value it can be concluded that the substance 3,7-dimethylocta-2,6-dien-1-yl 2-methylpropanoate is considered to be toxic to aquatic environment. Since the chemical is readily biodegradable in nature, chemical 3,7-dimethylocta-2,6-dien-1-yl 2-methylpropanoate can be considered as non-toxic to aquatic organisms and can be considered to be not classified as per the CLP classification criteria.

 

In a weight of evidence study from peer reviewed journal (Marina Isidori et. al, 2007) of the read across chemical Isopropyl 2 -[4 -(4 -chlorobenzoyl)phenoxy]-2 -methylpropanoate (CAS no. 49562 -28 -9), short term toxicity to Pseudokirchneriella subcapitata (green algae) study was carried out for 72 hrs. The study was performed according to ISO 8692 (Water Quality - Fresh Water Algal Growth Inhibition Test with Scenedesmus subspicatus and Selenastrum capricornutum).The study was based on the effects of the read across compound Isopropyl 2 -[4 -(4 -chlorobenzoyl)phenoxy]-2 -methylpropanoate (CAS no. 49562 -28 -9) on green algae in a static fresh water system at a temperature of 25°C. The algal inoculum was taken from an exponentially growing pre-culture and added to 25 ml of test solution to obtain an initial cell density of the order of 104 cells/ml. Test compound was tested in five concentrations and three replicates. Flasks were placed in a growth chamber at 25 °C under 8000lux. The cell density was measured at 0 time and every 24 h for 3 days by an electronic particle dual threshold counter (Coulter Counter Z2, 100μm capillary, Instrumentation Laboratory, Miami, FL, USA). From these data the algal growth inhibition in percentage was calculated by integrating the mean values from t0 to t72 h (area under the curve). Inhibition (%) values were tabulated against log-transformed data of concentrations to evaluate the test concentration corresponding to 50% algal growth inhibition. Based on effect on growth rate of the test organism Pseudokirchneriella subcapitata, the 72 hr EC50, NOEC and LOEC value was determined to be 19.84, 3.12 and 6.25 mg/l respectively. Thus, based on the EC50 value, it can be concluded that the substance Isopropyl 2 -[4 -(4 -chlorobenzoyl)phenoxy]-2 -methylpropanoate can be considered as toxic to aquatic organisms. Since the chemical is readily biodegradable in nature, chemical Isopropyl 2 -[4 -(4 -chlorobenzoyl)phenoxy]-2 -methylpropanoate can be considered as non-toxic to aquatic organisms and thus can be considered to be not classified as per the CLP classification criteria.

 

For another read across chemical hexadec-11-en-1-yl acetate (CAS no. 34010-21-4), short term toxicity to Desmodesmus subspicatus (green algae) study was carried out for 72 hrs (Esmeralda Rosa et. al; 2006). The study was performed according to EU Method C.3 (Algal Inhibition test).The study was based on the effects of the read across compound hexadec-11-en-1-yl acetate (CAS no. 34010-21-4) on green algae in a static fresh water system at a temperature of 23±2°C under continuous white light (120µE/s/m2). Desmodesmus subspicatus (formely known as Scenesdesmus subspicatus, CCAP 276/20)was used as a test organism obtained from the Culture Collection Algae and Protozoa (Cumbria, UK).Initial cell densities were adjusted at 104 cells/ml using a calibration curve of chlorophyll absorbance (λ= 650 nm) versus cell number and appropriate dilution of pre-culture. Test chemical conc. used for the study was 1, 5, 10, 25 and 50 mg/l (nominal concentration) and 0.77, 4.13, 7.95, 24.35 and 36.66 mg/l (measured concentration), respectively. Aqueous solutions of the chemicals were prepared by adding the appropriate amounts of stocks in acetone (HPLC grade; <0.5 ml l−1) to 100 ml borosilicate flasks and allowing the acetone to evaporate. The flask was then filled with the appropriate volume of algal medium, mixed thoroughly and sonicated for 1 h. Borosilicate flasks of 100 ml was used as a test vessel for the study. Test vessel was kept in suspension by continuous shaking at 60 rpm. Algal medium was prepared according to the protocol of EEC Directive 92/69/EEC using deionized water and analytically pure chemicals. The average growth rates were calculated from cell numbers based on measurements of chlorophyll absorbance at λ= 650 nm in a dual-beam spectrophotometer (Uvikon 941) and converted to proportional responses relative to controls. Median effect concentration levels (EC50) for the chemicals were estimated from concentration–response curves, obtained considering proportional algae growth, survival and feeding responses relative to control treatments, by fitting observed responses to the non-linear allosteric decay regression model. Based on effect on growth rate of the test organism Desmodesmus subspicatus, the 72 hr EC50 value was determined to be 103.74 mg/l, respectively. Thus, based on the EC50 value, it can be concluded that the substance hexadec-11-en-1-yl acetate can be considered as non-toxic to aquatic organisms and thus can be considered to be not classified as per the CLP classification criteria.

 

Thus, based on the overall reported results for target chemical 3,7 -dimethylocta-2,6 -dien-1 -yl 2 -methylpropanoate (OECD QSAR toolbox version 3.3, 2017) and for its read across substance (from peer reviewed journal), it can be concluded that the test substance 3,7 -dimethylocta-2,6 -dien-1 -yl 2 -methylpropanoate can be considered as non-toxic to aquatic environment and can be considered to be not classified as per the CLP classification criteria.