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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.3.3 and QMRF report has been attached.
Reference:
Composition 0
Qualifier:
according to
Guideline:
other: Predicted data
Principles of method if other than guideline:
Prediction is done using QSAR Toolbox version 3.3 with log kow as the primary discriptors.
GLP compliance:
not specified
Test material information:
Composition 1
Specific details on test material used for the study:
- Name of test material (IUPAC name): (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one- Common name: d-Carvone- Molecular formula: C10H14O- Molecular weight: 150.22 g/mol- Smiles notation: C1[C@H](CC=C(C1=O)C)C(C)=C- InChl: 1S/C10H14O/c1-7(2)9-5-4-8(3)10(11)6-9/h4,9H,1,5-6H2,2-3H3/t9-/m0/s1- Substance type: Organic- Physical state: Colorless to pale-yellow 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
Key result
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
154.67 mg/L
Nominal / measured:
estimated
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: not toxic

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" )  and ("e" and ( not "f") )  )  and ("g" and ( not "h") )  )  and ("i" and ( not "j") )  )  and ("k" and ( not "l") )  )  and "m" )  and ("n" and ( not "o") )  )  and ("p" and "q" )  )

Domain logical expression index: "a"

Referential boundary: The target chemical should be classified as Michael addition AND Michael addition >> Polarised Alkenes-Michael addition AND Michael addition >> Polarised Alkenes-Michael addition >> Alpha, beta- unsaturated ketones by DNA binding by OECD

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as Michael Addition AND Michael Addition >> Michael addition on conjugated systems with electron withdrawing group AND Michael Addition >> Michael addition on conjugated systems with electron withdrawing group >> alpha,beta-Carbonyl compounds with polarized double bonds  by Protein binding by OASIS v1.3

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as Michael addition AND Michael addition >> Polarised Alkenes AND Michael addition >> Polarised Alkenes >> Polarised alkene - ketones by Protein binding by OECD

Domain logical expression index: "d"

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

Domain logical expression index: "e"

Referential boundary: The target chemical should be classified as No alert found by DNA binding by OASIS v.1.3

Domain logical expression index: "f"

Referential boundary: The target chemical should be classified as Michael addition OR Michael addition >> Quinone type compounds OR Michael addition >> Quinone type compounds >> Quinone methides OR Radical OR Radical >> ROS formation after GSH depletion OR Radical >> ROS formation after GSH depletion >> Quinone methides by DNA binding by OASIS v.1.3

Domain logical expression index: "g"

Referential boundary: The target chemical should be classified as Michael addition AND Michael addition >> Polarised Alkenes-Michael addition AND Michael addition >> Polarised Alkenes-Michael addition >> Alpha, beta- unsaturated ketones by DNA binding by OECD

Domain logical expression index: "h"

Referential boundary: The target chemical should be classified as No alert found by DNA binding by OECD

Domain logical expression index: "i"

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

Domain logical expression index: "j"

Referential boundary: The target chemical should be classified as Carbon with 4 single bonds & no hydrogens by Bioaccumulation - metabolism alerts

Domain logical expression index: "k"

Referential boundary: The target chemical should be classified as Alkene AND Allyl AND Cycloalkene AND Cycloketone by Organic Functional groups

Domain logical expression index: "l"

Referential boundary: The target chemical should be classified as Isopropyl by Organic Functional groups

Domain logical expression index: "m"

Similarity boundary:Target: CC(=C)C1CC=C(C)C(=O)C1
Threshold=20%,
Dice(Atom centered fragments)
Atom type; Count H attached; Hybridization

Domain logical expression index: "n"

Referential boundary: The target chemical should be classified as Allyl AND Cycloalkene AND Cycloketone AND Overlapping groups by Organic Functional groups (nested)

Domain logical expression index: "o"

Referential boundary: The target chemical should be classified as Acid anhydride by Organic Functional groups (nested)

Domain logical expression index: "p"

Parametric boundary:The target chemical should have a value of log Kow which is >= -0.264

Domain logical expression index: "q"

Parametric boundary:The target chemical should have a value of log Kow which is <= 4.09

Conclusions:
Based on the prediction done using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the closest read across substances, the toxicity to aquatic invertebrate was predicted (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one. EC50 growth rate value was estimated to be 154.67 mg/l for Pseudokirchneriella subcapitata for 72 hrs duration. It was concluded that (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one (CAS: 2244-16-8) was likely to be not toxic to aquatic algae.
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 closest read across substances, the toxicity to aquatic invertebrate was predicted (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one. EC50 growth rate value was estimated to be 154.67 mg/l for Pseudokirchneriella subcapitata for 72 hrs duration. It was concluded that (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one (CAS: 2244-16-8) was likely to be not toxic to aquatic algae.

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 closest read across substances, the toxicity to aquatic invertebrate was predicted (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one. EC50 growth rate value was estimated to be 154.67 mg/l for Pseudokirchneriella subcapitata for 72 hrs duration. It was concluded that (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one (CAS: 2244-16-8) was likely to be not toxic to aquatic algae.

Key value for chemical safety assessment

EC50/LC50 for freshwater algae:
154.67 mg/L

Additional information

Following studies of target chemical and structurally similar read across includes predicted data and experimental data to conclude the toxicity extent of (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one (CAS: 2244-16-8) towards aquatic algae is summarized as follows:

Based on the prediction done using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the closest read across substances, the toxicity to aquatic invertebrate was predicted (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one. EC50 growth rate value was estimated to be 154.67 mg/l for Pseudokirchneriella subcapitata for 72 hrs duration. It was concluded that (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one (CAS: 2244-16-8) was likely to be not toxic to aquatic algae.

The above predicted data of target chemical is supported by the experimental study of structurally similar read across 2-Hydroxyethyl methacrylate (CAS: 868 -77-9) from the (J check) 2018,, suggests that the Toxicity to aquatic algae and cyanobacteria test was carried out to study the effects of 2-Hydroxyethyl methacrylate on algae for 72 hr.

The effective concentration EC50 to 50% of algae when exposed to 2-Hydroxyethyl methacrylate for 72 hr is 710 mg/L.It can be concluded from the value that the 2-Hydroxyethyl methacrylate is not toxic/toxic to the aquatic algae and can be considered as “not classified” as per the classification criteria for aquatic environment.

Another supporting experimental study for the structurally similar read across 1,1,3-Trimethyl-3-cyclohexene-5-one (CAS: 78-59-1) from the Environmental Protection Agency 1978, also suggests that the Toxicity to aquatic algae test was carried for 96 hr to study the effects of 1,1,3-Trimethyl-3-cyclohexene-5-one on aquatic algae.Decreasing trend of Population (Chlorophyll A concentration) was measured during the test.

Effective concentration EC50 to 50% of Skeletonema costatum when exposed to 1,1,3-Trimethyl-3-cyclohexene-5-one for 96 hr is 110 mg/L. It can be concluded from the value that the 1,1,3-Trimethyl-3-cyclohexene-5-one is not toxic to the aquatic algae and can be considered as “not classified” as per the classification criteria for aquatic environment.

Thus based on the effect concentrations which is in the range 110 mg/L to710 mg/lgive the conclusion that test substance (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one (CAS: 2244-16-8) is likely to be not toxic to aquatic algae at environmentally relevant concentrations and applying weight of evidence approach it can be considered to be “not classified” as per the CLP classification criteria.