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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 the QMRF report has been attached.
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Principles of method if other than guideline:
Prediction was done using the OECD QSAR toolbox version 3.3.
GLP compliance:
not specified
Specific details on test material used for the study:
- Name of test material : 4'-Cyanoacetophenone
- Molecular formula : C9H7NO
- Molecular weight : 145.16 g/mol
- Smiles notation : CC(=O)c1ccc(C#N)cc1
- InChl : 1S/C9H7NO/c1-7(11)9-4-2-8(6-10)3-5-9/h2-5H,1H3
- Substance type: Organic
- Physical state: Solid
Analytical monitoring:
not specified
Vehicle:
not specified
Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
No data available
Test type:
static
Water media type:
freshwater
Total exposure duration:
72 h
Post exposure observation period:
No data available
Hardness:
24 mg/L as CaCO3
Test temperature:
22-23°C
pH:
8.4-9.6
Reference substance (positive control):
not specified
Key result
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
121.398 mg/L
Nominal / measured:
estimated
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: Nontoxic

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 ("h" and ( not "i") )  )  and "j" )  and "k" )  and ("l" and "m" )  )

Domain logical expression index: "a"

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

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as Acetylenic Carbon [#C] OR Aliphatic Carbon [CH] OR Aliphatic Carbon [-CH2-] OR Aliphatic Carbon [-CH3] OR Aromatic Carbon [C] OR Carbonyl, aliphatic attach [-C(=O)-] OR Carbonyl, olefinic attach [-C(=O)-] OR Carbonyl, one aromatic attach [-C(=O)-] OR Cyano, aromatic attach [-C#N] OR Miscellaneous sulfide (=S) or oxide (=O) OR Olefinic carbon [=CH- or =C<] by Organic functional groups (US EPA) ONLY

Domain logical expression index: "c"

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

Domain logical expression index: "d"

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

Domain logical expression index: "e"

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

Domain logical expression index: "f"

Referential boundary: The target chemical should be classified as Michael addition OR Michael addition >> Polarised Alkenes OR Michael addition >> Polarised Alkenes >> Polarised alkene - cyano OR Michael addition >> Polarised Alkenes >> Polarised alkene - pyridines OR Schiff Base Formers OR Schiff Base Formers >> Direct Acting Schiff Base Formers OR Schiff Base Formers >> Direct Acting Schiff Base Formers >> 1-3-Dicarbonyls by Protein binding by OECD

Domain logical expression index: "g"

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

Domain logical expression index: "h"

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

Domain logical expression index: "i"

Referential boundary: The target chemical should be classified as Alkali Earth OR Halogens OR Metalloids OR Rare Earth OR Transition Metals by Groups of elements

Domain logical expression index: "j"

Similarity boundary:Target: CC(=O)c1ccc(C#N)cc1
Threshold=10%,
Dice(Atom centered fragments)
Atom type; Count H attached; Hybridization

Domain logical expression index: "k"

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

Domain logical expression index: "l"

Parametric boundary:The target chemical should have a value of log Kow which is >= 0.278

Domain logical expression index: "m"

Parametric boundary:The target chemical should have a value of log Kow which is <= 2.64

Validity criteria fulfilled:
not specified
Conclusions:
The EC50 value was estimated to be 121.398 mg/l when 4'-Cyanoacetophenone exposed to Pseudokirchneriella subcapitata for 72 hrs.
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, toxicity on Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum) was predicted for 4'-Cyanoacetophenone (1443-80-7). The EC50 value was estimated to be 121.398 mg/l when 4'-Cyanoacetophenone exposed to Pseudokirchneriella subcapitata for 72 hrs.

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, toxicity on Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum) was predicted for 4'-Cyanoacetophenone (1443-80-7). The EC50 value was estimated to be 121.398 mg/l when 4'-Cyanoacetophenone exposed to Pseudokirchneriella subcapitata for 72 hrs.

Key value for chemical safety assessment

EC50 for freshwater algae:
121.398 mg/L

Additional information

Based on the various predicted data for target chemical 4'-Cyanoacetophenone (1443-80-7) and experimental data for read across chemical studyhave been reviewed to determine the toxic nature of target chemical 4'-Cyanoacetophenone the studies are as mentioned below:

 

In the first predicted weight of evidence report for the 4'-Cyanoacetophenone (1443-80-7) from SSS (QSAR, 2017) toxicity study was carried out. 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, toxicity on Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum) was predicted for 4'-Cyanoacetophenone (1443-80-7). The EC50 value was estimated to be 121.398 mg/l when 4'-Cyanoacetophenone exposed to Pseudokirchneriella subcapitata for 72 hrs.

 

In the second predicted weight of evidence report for the 4'-Cyanoacetophenone (1443-80-7) from EPIsuite, Based on the prediction done using theEPI Suite ECOSAR version 1.10, the short term toxicity on green algae was predicted for test substance  4'-Cyanoacetophenone (CAS no:1443 -80 -7). On the basis of effects observed in a static freshwater system, the effect concentration EC50 value for the substance is estimated to be 174.684 mg/l for green algae for 72 hrs duration. Based on this value, it can be concluded that the test chemical   4'-Cyanoacetophenone  can be considered as non-toxic to green algae at environmentally relevant concentrations and can be considered not-classified as per the CLP classification criteria.

 

Similarly in the third weight of evidence study for the RA chemical (586-37-8) from ABITEC lab, 2016, 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 substance 3-methoxyacetophenone does not exhibittoxicity to aquatic algae (Desmodesmus subspicatus).

 

Thus based on the above data sources for target chemical 4'-Cyanoacetophenone (1443-80-7) from various experimental studies and predicted studies from QSAR, ABITEC lab, HSDB, ECOTOX, GSBL, it was summarized that the chemical was nontoxic and can be consider to be not classified as toxic as per the CLP classification criteria.