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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:
calculation (if not (Q)SAR)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
accepted calculation method
Justification for type of information:
Data is from Danish QSAR database.
Qualifier:
according to guideline
Guideline:
other: Modeling database
Principles of method if other than guideline:
Determination of estimated 72 hrs EC50 value of test substance on Pseudokirchneriella subcapitata by three different models i.e, Battery, Leadscope and SciQSAR used within Danish QSAR database. It is a continuous (Q)SAR model based on structural features and numeric molecular descriptors.
GLP compliance:
not specified
Specific details on test material used for the study:
- Name of test material (IUPAC name): Trisodium 4-[[1-hydroxy-6-[[[[5-hydroxy-6-(phenylazo)-7-sulphonato-2-naphthyl]amino]carbonyl]amino]-3-sulphonato-2-naphthyl]azo]benzoate
- Common name: trisodium 4-[[1-hydroxy-6-[[[[5-hydroxy-6-(phenylazo)-7-sulphonato-2-naphthyl]amino]carbonyl]amino]-3-sulphonato-2-naphthyl]azo]benzoate
- Molecular formula: C34H21N6Na3O11S2
- Molecular weight: 822.673 g/mol
- Smiles notation: c12c(cc(c(c2S(=O)(=O)[O-])\N=N\c2ccc(cc2)C(=O)[O-])O)cc(NC(=O)Nc2cc3cc(S(=O)(=O)[O-])c(\N=N\c4ccccc4)c(c3cc2)O)cc1.[Na+].[Na+].[Na+]
-InChl:1S/C34H24N6O11S2.3Na/c41-27-16-19-14-24(11-13-26(19)32(53(49,50)51)29(27)39-38-22-8-6-18(7-9-22)33(43)44)36-34(45)35-23-10-12-25-20(15-23)17-28(52(46,47)48)30(31(25)42)40-37-21-4-2-1-3-5-21;;;/h1-17,41-42H,(H,43,44)(H2,35,36,45)(H,46,47,48)(H,49,50,51);;;/q;3*+1/p-3/b39-38+,40-37+;;;
- Substance type: Organic
-Physical sttate: Solid
Analytical monitoring:
not specified
Vehicle:
not specified
Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
TEST ORGANISM
- Common name: Selenastrum Capricornutum
Test type:
static
Water media type:
freshwater
Total exposure duration:
72 h
Remarks on exposure duration:
Estimated data
Key result
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
2 809.387 mg/L
Nominal / measured:
estimated
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: Domain applicability - Battery : IN

Table: Table showing the Pseudokirchneriella subcapitata 72 hr EC50 values estimated by two different models i.e, Leadscope and SciQSAR & the average EC50 value was given by the third model i.e, Battery model.

DK

Battery

Leadscope

SciQSAR

Pseudokirchneriella subcapitata 72 hr EC50 (mg/l)

2809.387

5605.769

13.00574

Domain

IN

IN

IN

 

Where,

IN = inside applicability domain

Validity criteria fulfilled:
not specified
Conclusions:
Based on inhibition in growth rate of Pseudokirchneriella subcapitata, the estimated 72 hrs EC50 value by three different model i.e, Battery, Leadscope and SciQSAR used within Danish QSAR database was evaluated to be 2809.387 mg/l for trisodium 4-[(E)-2-{1-hydroxy-6-[({5-hydroxy-6-[(E)-2-phenyldiazen-1-yl]-7-sulfonatonaphthalen-2-yl}.
Executive summary:

Based on the prediction done using thethree different models i.e, Battery, Leadscope and SciQSAR used within Danish QSAR database, the short term toxicity on green algae was predicted for test substance trisodium 4-[(E)-2-{1-hydroxy-6-[({5-hydroxy-6-[(E)-2-phenyldiazen-1-yl]-7-sulfonatonaphthalen-2-yl}(CAS:6598 -63 -6). The average EC50 value was given by the third model i.e, Battery model. On the basis of effects observed in a static freshwater system, the effect concentration EC50 value for the substance trisodium 4-[(E)-2-{1-hydroxy-6-[({5-hydroxy-6-[(E)-2-phenyldiazen-1-yl]-7-sulfonatonaphthalen-2-yl} is estimated to be 2809.387 mg/l for Pseudokirchneriella subcapitata during 72 hr exposure duration. Thus, on the basis of EC50 value,it can be concluded that the test chemical trisodium 4-[(E)-2-{1-hydroxy-6-[({5-hydroxy-6-[(E)-2-phenyldiazen-1-yl]-7-sulfonatonaphthalen-2-yl}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.

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 algae was predicted trisodium 4-[(E)-2-{1-hydroxy-6-[({5-hydroxy-6-[(E)-2-phenyldiazen-1-yl]-7-sulfonatonaphthalen-2-yl} (CAS: 6598-63-6). Growth rate inhibition value was estimated to be 115.066 mg/l for Pseudokirchneriella subcapitata for 72  hrs duration. It was concluded that trisodium 4-[(E)-2-{1-hydroxy-6-[({5-hydroxy-6-[(E)-2-phenyldiazen-1-yl]-7-sulfonatonaphthalen-2-yl} (CAS: 6598-63-6) was likely to be not toxic to aquatic algae.

Key value for chemical safety assessment

EC50 for freshwater algae:
115.066 mg/L

Additional information

Following studies include the experimental studies for the structurally similar read across to conclude the toxicity extent of trisodium 4-[(E)-2-{1-hydroxy-6-[({5-hydroxy-6-[(E)-2-phenyldiazen-1-yl]-7-sulfonatonaphthalen-2-yl} (CAS: 6598-63-6) 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 algae was predicted trisodium 4-[(E)-2-{1-hydroxy-6-[({5-hydroxy-6-[(E)-2-phenyldiazen-1-yl]-7-sulfonatonaphthalen-2-yl} (CAS: 6598-63-6). Growth rate inhibition value was estimated to be 115.066 mg/l for Pseudokirchneriella subcapitata for 72  hrs duration. It was concluded that trisodium 4-[(E)-2-{1-hydroxy-6-[({5-hydroxy-6-[(E)-2-phenyldiazen-1-yl]-7-sulfonatonaphthalen-2-yl} (CAS: 6598-63-6) was likely to be not toxic to aquatic algae.

Similar prediction is done for the target chemical by using the three different models i.e, Battery, Leadscope and SciQSAR used within Danish QSAR database, the short term toxicity on green algae was predicted for test substancetrisodium 4-[(E)-2-{1-hydroxy-6-[({5-hydroxy-6-[(E)-2-phenyldiazen-1-yl]-7-sulfonatonaphthalen-2-yl}(CAS:6598 -63 -6). The average EC50 value was given by the third model i.e, Battery model. On the basis of effects observed in a static freshwater system, the effect concentration EC50 value for the substancetrisodium 4-[(E)-2-{1-hydroxy-6-[({5-hydroxy-6-[(E)-2-phenyldiazen-1-yl]-7-sulfonatonaphthalen-2-yl} is estimated to be 2809.387 mg/l for Pseudokirchneriella subcapitata during 72 hr exposure duration. Thus, on the basis of EC50 value,it can be concluded that the test chemicaltrisodium 4-[(E)-2-{1-hydroxy-6-[({5-hydroxy-6-[(E)-2-phenyldiazen-1-yl]-7-sulfonatonaphthalen-2-yl}can be considered asnon-toxicto green algae at environmentally relevant concentrations and can be considered "not-classified" as per the CLP classification criteria.

The Predicted data for the target chemical is assissted by the experimental study of structurally similar read across Metformin (CAS: 657 -24 -9) from the publication Toxicology Letters 2003, Toxicity to aquatic algae and cyanobacteria assessment was carried out to study the effects of Metformin on Desmodesmus subspicatus. Effective concentration to 50% of Desmodesmus subspicatus at which decrease in population growth rate was measured is 320 mg/L. It can be concluded that the Metformin is not toxic to the aquatic environment and can be considered as “not classified” as CLP regulation.

Similar experimental study of another structurally simialr read across Benzoic Acid (CAS: 65 -85 -0) from the publication Journal of Hazardous Materials 2009, suggests that the Short term toxicity of Benzoic acid toPseudokirchneriella subcapitata(green algae) study was carried out for 48 hrs.The study was based on the effects of the test compound onPseudokirchneriella subcapitatain a static fresh water system. On the basis of population of the test organismPseudokirchneriella subcapitata(green algae), the 48 hr EC50 value was determined to be 207.5 mg/l. Thus, based on this value, it can be concluded that the substance Benzoic acid can be considered as non-toxic to aquatic organisms and thus cannot be classified as hazardous as per the CLP criteria.

Thus based on the effect concentrations which is in range of 115.066 mg/l to 2809.387 mg/L gives the conclusion that test substance trisodium 4-[(E)-2-{1-hydroxy-6-[({5-hydroxy-6-[(E)-2-phenyldiazen-1-yl]-7-sulfonatonaphthalen-2-yl} (CAS: 6598-63-6) was likely to be not toxic to algae at environmentally relevant concentrations and applying weight of evidence approach it can be considered to benot classifiedas per the CLP classification criteria for aquatic environment.

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