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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.
Qualifier:
according to guideline
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
Specific details on test material used for the study:
- Name of test material (IUPAC name): 1-(4-methoxyphenyl)propan-2-one
- Common name: 4-Methoxyphenylacetone
- Molecular formula: C10H12O2
- Molecular weight: 164.203 g/mol
- Smiles notation: c1(ccc(OC)cc1)CC(C)=O
- InChl: 1S/C10H12O2/c1-8(11)7-9-3-5-10(12-2)6-4-9/h3-6H,7H2,1-2H3
- Substance type: Organic
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.:
203.376 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" )  and ("c" and ( not "d") )  )  and ("e" and ( not "f") )  )  and ("g" and ( not "h") )  )  and "i" )  and "j" )  and "k" )  and ("l" and ( not "m") )  )  and "n" )  and ("o" and ( not "p") )  )  and "q" )  and "r" )  and "s" )  and "t" )  and "u" )  and "v" )  and "w" )  and "x" )  and "y" )  and ("z" and "aa" )  )

Domain logical expression index: "a"

Referential boundary: The target chemical should be classified as Nucleophilic addition AND Nucleophilic addition >> Addition to carbon-hetero double bonds AND Nucleophilic addition >> Addition to carbon-hetero double bonds >> Ketones by Protein binding by OASIS v1.3

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as Class 1 (narcosis or baseline toxicity) by Acute aquatic toxicity classification by Verhaar (Modified)

Domain logical expression index: "c"

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

Domain logical expression index: "d"

Referential boundary: The target chemical should be classified as AN2 OR AN2 >> Schiff base formation by aldehyde formed after metabolic activation OR AN2 >> Schiff base formation by aldehyde formed after metabolic activation >> Geminal Polyhaloalkane Derivatives OR AN2 >> Shiff base formation for aldehydes OR AN2 >> Shiff base formation for aldehydes >> Geminal Polyhaloalkane Derivatives OR Radical OR Radical >> Radical mechanism by ROS formation (indirect) or direct radical attack on DNA OR Radical >> Radical mechanism by ROS formation (indirect) or direct radical attack on DNA >> Organic Peroxy Compounds OR Radical >> Radical mechanism via ROS formation (indirect) OR Radical >> Radical mechanism via ROS formation (indirect) >> Geminal Polyhaloalkane Derivatives OR SN1 OR SN1 >> Alkylation after metabolically formed carbenium ion species OR SN1 >> Alkylation after metabolically formed carbenium ion species >> Polycyclic Aromatic Hydrocarbon Derivatives OR SN2 OR SN2 >> Acylation involving a leaving group  OR SN2 >> Acylation involving a leaving group  >> Geminal Polyhaloalkane Derivatives OR SN2 >> Acylation involving a leaving group after metabolic activation OR SN2 >> Acylation involving a leaving group after metabolic activation >> Geminal Polyhaloalkane Derivatives OR SN2 >> Alkylation by epoxide metabolically formed after E2 reaction OR SN2 >> Alkylation by epoxide metabolically formed after E2 reaction >> Monohaloalkanes OR SN2 >> Alkylation, direct acting epoxides and related after P450-mediated metabolic activation OR SN2 >> Alkylation, direct acting epoxides and related after P450-mediated metabolic activation >> Polycyclic Aromatic Hydrocarbon Derivatives OR SN2 >> Alkylation, nucleophilic substitution at sp3-carbon atom OR SN2 >> Alkylation, nucleophilic substitution at sp3-carbon atom >> Monohaloalkanes OR SN2 >> Direct acylation involving a leaving group OR SN2 >> Direct acylation involving a leaving group >> Acyl Halides OR SN2 >> DNA alkylation OR SN2 >> DNA alkylation >> Vicinal Dihaloalkanes OR SN2 >> Internal SN2 reaction with aziridinium and/or cyclic sulfonium ion formation (enzymatic) OR SN2 >> Internal SN2 reaction with aziridinium and/or cyclic sulfonium ion formation (enzymatic) >> Vicinal Dihaloalkanes OR SN2 >> Nucleophilic substitution after carbenium ion formation OR SN2 >> Nucleophilic substitution after carbenium ion formation >> Monohaloalkanes OR SN2 >> Nucleophilic substitution at sp3 carbon atom after thiol (glutathione) conjugation OR SN2 >> Nucleophilic substitution at sp3 carbon atom after thiol (glutathione) conjugation >> Geminal Polyhaloalkane Derivatives by DNA binding by OASIS v.1.3

Domain logical expression index: "e"

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

Domain logical expression index: "f"

Referential boundary: The target chemical should be classified as Michael addition OR Michael addition >> P450 Mediated Activation to Quinones and Quinone-type Chemicals OR Michael addition >> P450 Mediated Activation to Quinones and Quinone-type Chemicals >> Arenes OR Michael addition >> P450 Mediated Activation to Quinones and Quinone-type Chemicals >> Hydroquinones OR Michael addition >> Polarised Alkenes-Michael addition OR Michael addition >> Polarised Alkenes-Michael addition >> Alpha, beta- unsaturated esters OR SN1 OR SN1 >> Iminium Ion Formation OR SN1 >> Iminium Ion Formation >> Aliphatic tertiary amines OR SN1 >> Nitrenium Ion formation OR SN1 >> Nitrenium Ion formation >> Secondary aromatic amine OR SN2 OR SN2 >> SN2 at an sp3 Carbon atom OR SN2 >> SN2 at an sp3 Carbon atom >> Aliphatic halides by DNA binding by OECD

Domain logical expression index: "g"

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

Domain logical expression index: "h"

Referential boundary: The target chemical should be classified as Acylation OR Acylation >> Direct Acylation Involving a Leaving group OR Acylation >> Direct Acylation Involving a Leaving group >> Acetates OR Acylation >> Direct Acylation Involving a Leaving group >> Azlactone OR Michael addition OR Michael addition >> Polarised Alkenes OR Michael addition >> Polarised Alkenes >> Polarised alkene - pyridines by Protein binding by OECD

Domain logical expression index: "i"

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

Domain logical expression index: "j"

Referential boundary: The target chemical should be classified as Class 1 (narcosis or baseline toxicity) by Acute aquatic toxicity classification by Verhaar (Modified) ONLY

Domain logical expression index: "k"

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

Domain logical expression index: "l"

Referential boundary: The target chemical should be classified as Neutral Organics by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "m"

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

Domain logical expression index: "n"

Referential boundary: The target chemical should be classified as Bioavailable by Lipinski Rule Oasis ONLY

Domain logical expression index: "o"

Referential boundary: The target chemical should be classified as Non-Metals by Groups of elements

Domain logical expression index: "p"

Referential boundary: The target chemical should be classified as Halogens by Groups of elements

Domain logical expression index: "q"

Similarity boundary:Target: CC(=O)Cc1ccc(OC)cc1
Threshold=20%,
Dice(Atom centered fragments)
Atom type; Count H attached; Hybridization

Domain logical expression index: "r"

Similarity boundary:Target: CC(=O)Cc1ccc(OC)cc1
Threshold=40%,
Dice(Atom centered fragments)
Atom type; Count H attached; Hybridization

Domain logical expression index: "s"

Referential boundary: The target chemical should be classified as Alkylarylether AND Aromatic compound AND Carbonyl compound AND Ether AND Ketone by Organic functional groups, Norbert Haider (checkmol) ONLY

Domain logical expression index: "t"

Referential boundary: The target chemical should be classified as Alkylarylether AND Aromatic compound AND Carbonyl compound AND Ether AND Ketone by Organic functional groups, Norbert Haider (checkmol) ONLY

Domain logical expression index: "u"

Referential boundary: The target chemical should be classified as Aryl AND Ether AND Ketone by Organic Functional groups ONLY

Domain logical expression index: "v"

Referential boundary: The target chemical should be classified as Aryl AND Ether AND Ketone by Organic Functional groups ONLY

Domain logical expression index: "w"

Referential boundary: The target chemical should be classified as Aryl AND Ether AND Ketone by Organic Functional groups ONLY

Domain logical expression index: "x"

Referential boundary: The target chemical should be classified as Aryl AND Ether AND Ketone by Organic Functional groups ONLY

Domain logical expression index: "y"

Referential boundary: The target chemical should be classified as Aryl AND Ether AND Ketone AND Overlapping groups by Organic Functional groups (nested) ONLY

Domain logical expression index: "z"

Parametric boundary:The target chemical should have a value of log Kow which is >= 0.768

Domain logical expression index: "aa"

Parametric boundary:The target chemical should have a value of log Kow which is <= 2.56

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 algae was predicted 1-(4-methoxyphenyl)propan-2-one (CAS: 122-84-9). EC50 growth rate value was estimated to be 203.376 mg/l for Pseudokirchneriella subcapitata for 72 hrs duration. It was concluded that 1-(4-methoxyphenyl)propan-2-one (CAS: 122-84-9) 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 algae was predicted 1-(4-methoxyphenyl)propan-2-one (CAS: 122-84-9). EC50 growth rate value was estimated to be 203.376 mg/l for Pseudokirchneriella subcapitata for 72 hrs duration. It was concluded that 1-(4-methoxyphenyl)propan-2-one (CAS: 122-84-9) 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 algae was predicted 1-(4-methoxyphenyl)propan-2-one (CAS: 122-84-9). EC50 growth rate value was estimated to be 203.376 mg/l for Pseudokirchneriella subcapitata for 72 hrs duration. It was concluded that 1-(4-methoxyphenyl)propan-2-one (CAS: 122-84-9) was likely to be not toxic to aquatic algae.

Key value for chemical safety assessment

EC50 for freshwater algae:
203.376 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 1-(4-methoxyphenyl)propan-2-one (CAS: 122-84-9) 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 algae was predicted 1-(4-methoxyphenyl)propan-2-one (CAS: 122-84-9). EC50 growth rate value was estimated to be 203.376 mg/l for Pseudokirchneriella subcapitata for 72 hrs duration. It was concluded that 1-(4-methoxyphenyl)propan-2-one (CAS: 122-84-9) 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 4-methoxyphenylacetic acid (CAS No. 104-01-8) from the ABITEC Lab report 2017, suggests that the freshwater algal growth inhibition test was carried out on Desmodesmus subspicatus with the substance4-methoxyphenylacetic acid(CAS No.- 104 -01 -8) according to OECD Guideline 201.

The stock solution 150.0 mg/L was prepared by dissolving white powder in OECD growth medium. Test solutions of required concentrations were prepared by mixing the stock solution of the test sample with OECD growth medium and inoculum culture and tested at the concentrations 0, 0, 30.0, 45.0, 67.5, 100.0 and 150.0 mg/L.Effects on the growth rate of the organism were studied. The test was performed under static conditions in a static fresh water system at a temperature of 23± 2°C. Initial cell density of test organism used was 5x10(3) cells/ml. Determination of cell counting involve the use of microscope with counting chamber Cyrus I or electronic particle counter. ErC50 was calculated using non-linear regression by the software Prism 4.0.

The median effective concentration (ErC50) for the test substance,4-methoxyphenylacetic acid, in a freshwater algae Desmodesmus subspicatus was determined to be 106.9 mg/L on the basis of effects on growth rate in a 72 hour study with 95% Cl of 83.2 - 137.3 mg/L. Thus, based on this ErC50 value and according to CLP Criteria for aquatic classification of the substance, it is concluded that4-methoxyphenylacetic acid(CAS No.- 104 -01 -8) does not exhibits toxicity to aquatic algae (Desmodesmus subspicatus).

Another supporting experimental study for the structurally similar read across 3-methoxyacetophenone (CAS: 586-37-8) from the ABITEC Lab report 2016, also suggests that the Freshwater algal growth inhibition test was carried out on Desmodesmus subspicatus with the substance 3-methoxyacetophenone according to OECD Guideline 201.

The test substance was dissolved in OECD growth medium and tested at the concentrations 0, 2.2, 11, 25, 55 and 120 mg/L. Effects on the growth rate of the organism were studied.

The median effective concentration (ErC50) for the test substance, 3-methoxyacetophenone, in Desmodesmus subspicatus was determined to be 129.3 mg/L. Based on this ErC50 value and after comparing with CLP criteria for aquatic classification of the substance it is concluded that the substance3-methoxyaceto phenonedoes not exhibittoxicity to aquatic algae (Desmodesmus subspicatus).

Thus based on the effect concentrations which is in the range 106.9 mg/L to203.376 mg/lgive the conclusion that test substance 1-(4-methoxyphenyl)propan-2-one (CAS: 122-84-9) 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.