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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 QMRF report has been attached.
Reference:
Composition 1
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:
no
Test material information:
Composition 1
Specific details on test material used for the study:
- Name of test material (as cited in study report): 4-acetamido-5-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]anthranilic acid, sodium salt
- Molecular formula (if other than submission substance): C16-H18-N4-O10-S3.x-Na
- Molecular weight (if other than submission substance): 566.4984
- SMILES: [Na]_CC(=O)Nc1cc(N)c(C(O)=O)cc1N=Nc1ccc(S(=O)(=O)CCOS(O)(=O)=O)cc1
- InChI: 1S/C16H18N4O10S3.2Na/c1-10(21)18-14-8-13(17)16(32(24,25)26)9-15(14)20-19-11-2-4-12(5-3-11)31(22,23)7-6-30-33(27,28)29;;/h2-5,8-9H,6-7,17H2,1H3,(H,18,21)(H,24,25,26)(H,27,28,29);;/q;2*+1/p-2/b20-19+;;
Analytical monitoring:
not specified
Vehicle:
not specified
Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Key result
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
400.69 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" or "e" or "f" )  and ("g" and ( not "h") )  )  and ("i" and ( not "j") )  )  and ("k" and ( not "l") )  )  and ("m" and ( not "n") )  )  and ("o" and "p" )  )

Domain logical expression index: "a"

Referential boundary: The target chemical should be classified as Anilines (Acute toxicity) AND Not categorized AND Vinyl Sulfones by US-EPA New Chemical Categories

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as No alert found AND SN1 AND SN1 >> Nitrenium Ion formation AND SN1 >> Nitrenium Ion formation >> Aromatic azo by DNA binding by OECD

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as Non binder, non cyclic structure AND Strong binder, NH2 group by Estrogen Receptor Binding

Domain logical expression index: "d"

Referential boundary: The target chemical should be classified as Acylation AND Acylation >> Ester aminolysis AND Acylation >> Ester aminolysis >> Amides AND No alert found by Protein binding by OASIS v1.3

Domain logical expression index: "e"

Referential boundary: The target chemical should be classified as Acylation AND Acylation >> Direct Acylation Involving a Leaving group AND Acylation >> Direct Acylation Involving a Leaving group >> Acetates AND No alert found by Protein binding by OECD

Domain logical expression index: "f"

Referential boundary: The target chemical should be classified as Acid moiety OR Amides OR Anilines (Hindered) OR Inorganic Compound OR Salt by Aquatic toxicity classification by ECOSAR ONLY

Domain logical expression index: "g"

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

Domain logical expression index: "h"

Referential boundary: The target chemical should be classified as Non-covalent interaction OR Non-covalent interaction >> DNA intercalation OR Non-covalent interaction >> DNA intercalation >> DNA Intercalators with Carboxamide Side Chain OR Radical OR Radical >> Radical mechanism via ROS formation (indirect) OR Radical >> Radical mechanism via ROS formation (indirect) >> Single-Ring Substituted Primary Aromatic Amines OR SN1 OR SN1 >> Nucleophilic attack after metabolic nitrenium ion formation OR SN1 >> Nucleophilic attack after metabolic nitrenium ion formation >> Single-Ring Substituted Primary Aromatic Amines by DNA binding by OASIS v.1.3

Domain logical expression index: "i"

Referential boundary: The target chemical should be classified as Non binder, non cyclic structure AND Strong binder, NH2 group by Estrogen Receptor Binding

Domain logical expression index: "j"

Referential boundary: The target chemical should be classified as Non binder, MW>500 OR Non binder, without OH or NH2 group by Estrogen Receptor Binding

Domain logical expression index: "k"

Referential boundary: The target chemical should be classified as Amide   [-C(=O)-N  or -C(=S)-N] AND Aromatic acid   [-C(=O)-OH] AND Aromatic amine   [-NH2  or  -NH-] AND Aromatic-H AND Azo group   [-N=N-] AND Benzene AND -CH2-  [linear] AND Methyl  [-CH3] AND No alert found by Bioaccumulation - metabolism alerts

Domain logical expression index: "l"

Referential boundary: The target chemical should be classified as Aliphatic acid   [-C(=O)-OH] OR Aliphatic alcohol  [-OH] OR -CH-   [linear] by Bioaccumulation - metabolism alerts

Domain logical expression index: "m"

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

Domain logical expression index: "n"

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

Domain logical expression index: "o"

Parametric boundary:The target chemical should have a value of log Kow which is >= -4.34

Domain logical expression index: "p"

Parametric boundary:The target chemical should have a value of log Kow which is <= 0.235

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 on aquatic algae predicted for 2-amino-4-acetamido-5-[(E)-2-(4-{[2-(sulfooxy)ethane]sulfonyl}phenyl)diazen-1-yl]benzoic acid sodium (CAS: 94158-82-4). Effect concentration i.e EC50 value estimated to be 400.69 mg/l for Desmodesmus subspicatus for 72 hrs duration. It can be concluded that the 2-amino-4-acetamido-5-[(E)-2-(4-{[2-(sulfooxy)ethane]sulfonyl}phenyl)diazen-1-yl]benzoic acid sodium (CAS: 94158-82-4) is likely to be not toxic to aquatic algae, hence it can be considered to be “not classified” as per the CLP classification criteria for aquatic environment.
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 on aquatic algae predicted for 2-amino-4-acetamido-5-[(E)-2-(4-{[2-(sulfooxy)ethane]sulfonyl}phenyl)diazen-1-yl]benzoic acid sodium (CAS: 94158 -82-4). Effect concentration i.e EC50 value estimated to be 400.69 mg/l for Desmodesmus subspicatus for 72 hrs duration. It can be concluded that the 2-amino-4-acetamido-5-[(E)-2-(4-{[2-(sulfooxy)ethane]sulfonyl}phenyl)diazen-1-yl]benzoic acid sodium (CAS: 94158-82-4) is likely to be not toxic to aquatic algae, hence it can be considered to be “not classified” as per the CLP classification criteria for aquatic environment.

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 on aquatic algae predicted for 2-amino-4-acetamido-5-[(E)-2-(4-{[2-(sulfooxy)ethane]sulfonyl}phenyl)diazen-1-yl]benzoic acid sodium (CAS: 94158 -82-4). Effect concentration i.e EC50 value estimated to be 400.69 mg/l for Desmodesmus subspicatus for 72 hrs duration. It can be concluded that the 2-amino-4-acetamido-5-[(E)-2-(4-{[2-(sulfooxy)ethane]sulfonyl}phenyl)diazen-1-yl]benzoic acid sodium (CAS: 94158-82-4) is likely to be not toxic to aquatic algae, hence it can be considered to be “not classified” as per the CLP classification criteria for aquatic environment.

Key value for chemical safety assessment

EC50/LC50 for freshwater algae:
400.69 mg/L

Additional information

Following studies include the predicted data and experimental study for the target chemical and structurally similar read across to conclude the toxicity extent of 2-amino-4-acetamido-5-[(E)-2-(4-{[2-(sulfooxy)ethane]sulfonyl}phenyl)diazen-1-yl]benzoic acid sodium (CAS: 94158-82-4) 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 on aquatic algae predicted for 2-amino-4-acetamido-5-[(E)-2-(4-{[2-(sulfooxy)ethane]sulfonyl}phenyl)diazen-1-yl]benzoic acid sodium (CAS: 94158 -82-4). Effect concentration i.e EC50 value estimated to be 400.69 mg/l for Desmodesmus subspicatus for 72 hrs duration. It can be concluded that the 2-amino-4-acetamido-5-[(E)-2-(4-{[2-(sulfooxy)ethane]sulfonyl}phenyl)diazen-1-yl]benzoic acid sodium (CAS: 94158-82-4) is likely to be not toxic to aquatic algae, hence it can be considered to benot classifiedas per the CLP classification criteria for aquatic environment. 

The above predicted data of target chemical is supported by the experimental study of structurally similar read across disodium 5-acetamido-4-hydroxy-3-(phenyldiazenyl)naphthalene-2,7-disulfonate (CAS: 3734-67-6) from the ABITEC study report, suggests that A freshwater algal growth inhibition exposure assessment was used to test how a range of concentrations of CAS 3734-67-6 exerts different degrees of toxic effects on the growth of Desmodesmus subspicatusunder otherwise identical test conditions. The test was performed in close resemblance to OECD guideline 201 by ABITEC in Prague, Crez Republic. The standardized protocol used to obtain the herein described results was by the testing laboratory referred to asCSN EN ISO 8692. The 72 hours EC50 was by the testing laboratory defined as the concentration estimated to inhibit 50 per cent of the algae cell growth compared to unexposed cells after 27 hours of exposure. The nominal concentrations used for the exposure assessment were as follows:0, 20, 30, 45, 67 and 100 mg/L. The positive control/reference substance used in the tested showed an expected result and gave a EC50 that corresponded to previous exposures with this chemical in Desmodesmus subspicatus. In conclusion, the EC50 for CAS 3734-67-6 was 285.8 mg/L (95% C.I.: 173.5-470.8 mg/L) after 72 hours of exposure. It can be concluded from the value that the disodium 5-acetamido-4-hydroxy-3-(phenyldiazenyl)naphthalene-2,7-disulfonate is not toxic to the aquatic algae and can be considered as "not classified" as per the classification criteria for the aquatic environment.

Similar experimental study of another structurally similar read across N,N-dimethylformamide (CAS: 68-12-2) from publication Bulletin of Environmental Contamination and Toxicology 1983, indicates that the To study the aquatic toxicity of N,N-dimethylformamide the Static bottle test according to Miller, et al.(1978) or EPA-600/9-78-018 was carried out. In the highest concentration (1 ml/l) a statistically significant increase of algal growth was observed with respect to dry weight. The NOEC value for Selenastrum capricornutum in 14 days is 470 mg/l. It can be concluded that the N,N-dimethylformamide is not toxic and applying the weight of evidence approach it can be considered asnot classifiedas per CLP regulation.

 

Thus based on the effect concentrations which is in the range 285.8 mg/l to 470 mg/l give the conclusion that test substance 2-amino-4-acetamido-5-[(E)-2-(4-{[2 (sulfooxy)ethane]sulfonyl}phenyl)diazen-1-yl]benzoic acid sodium (CAS: 94158-82-4) was likely to be not toxic to aquatic invertebrate at environmentally relevant concentrations and applying weight of evidence approach it can be considered to benot classifiedas per the CLP classification criteria.