Disodium 4-hydroxynaphthalene-2,7-disulphonate

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

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: Disodium 4-hydroxynaphthalene-2,7-disulphonate
- Common name: 2,7-Naphthalenedisulfonic acid, 4-hydroxy-, sodium salt (1:2)
- Molecular formula: C10H6Na2O7S2
- Molecular weight: 348.2624 g/mol
- Smiles notation: c1cc2c(cc1S(=O)(=O)[O-])cc(cc2O)S(=O)(=O)[O-].[Na+].[Na+]
- InChl: 1S/C10H8O7S2.2Na/c11-10-5-8(19(15,16)17)4-6-3-7(18(12,13)14)1-2-9(6)10;;/h1-5,11H,(H,12,13,14)(H,15,16,17);;/q;2*+1/p-2
- Substance type: Organic

Analytical monitoring:

not specified

Vehicle:

not specified

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

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.:

108.77 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 ( not "k") )  )  and ("l" and ( not "m") )  )  and ("n" and ( not "o") )  )  and ("p" and ( not "q") )  )  and ("r" and "s" )  )

Domain logical expression index: "a"

Referential boundary: The target chemical should be classified as Strong binder, OH group by Estrogen Receptor Binding

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as Acid moiety AND Phenols AND Salt by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as Acid moiety AND Phenols AND Salt by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "d"

Referential boundary: The target chemical should be classified as Phenols, Poly by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "e"

Referential boundary: The target chemical should be classified as Aromatic alcohol  [-OH] AND Aromatic-H AND Naphthalene AND Number of fused 6-carbon aromatic rings AND Sulfonic acid / salt -> aromatic attach by Bioaccumulation - metabolism alerts

Domain logical expression index: "f"

Referential boundary: The target chemical should be classified as Triazole Ring by Bioaccumulation - metabolism alerts

Domain logical expression index: "g"

Referential boundary: The target chemical should be classified as Aromatic alcohol  [-OH] AND Aromatic-H AND Naphthalene AND Number of fused 6-carbon aromatic rings AND Sulfonic acid / salt -> aromatic attach by Bioaccumulation - metabolism alerts

Domain logical expression index: "h"

Referential boundary: The target chemical should be classified as Urea   [N-C(=O)-N] by Bioaccumulation - metabolism alerts

Domain logical expression index: "i"

Referential boundary: The target chemical should be classified as Very fast by Bioaccumulation - metabolism half-lives ONLY

Domain logical expression index: "j"

Referential boundary: The target chemical should be classified as Aromatic alcohol  [-OH] AND Aromatic-H AND Sulfonic acid / salt -> aromatic attach by Biodegradation fragments (BioWIN MITI)

Domain logical expression index: "k"

Referential boundary: The target chemical should be classified as Aromatic chloride   [-CL] by Biodegradation fragments (BioWIN MITI)

Domain logical expression index: "l"

Referential boundary: The target chemical should be classified as No alert found by Carcinogenicity (genotox and nongenotox) alerts by ISS

Domain logical expression index: "m"

Referential boundary: The target chemical should be classified as Structural alert for genotoxic carcinogenicity by Carcinogenicity (genotox and nongenotox) alerts by ISS

Domain logical expression index: "n"

Referential boundary: The target chemical should be classified as Not known precedent reproductive and developmental toxic potential by DART scheme v.1.0

Domain logical expression index: "o"

Referential boundary: The target chemical should be classified as Known precedent reproductive and developmental toxic potential by DART scheme v.1.0

Domain logical expression index: "p"

Referential boundary: The target chemical should be classified as Aryl AND Fused carbocyclic aromatic AND Naphtalene AND Phenol AND Sulfonic acid by Organic Functional groups

Domain logical expression index: "q"

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

Domain logical expression index: "r"

Parametric boundary:The target chemical should have a value of log BCF max which is >= 0.96 log(L/kg wet)

Domain logical expression index: "s"

Parametric boundary:The target chemical should have a value of log BCF max which is <= 2.78 log(L/kg wet)

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 invertebrate was predicted 2,7-Naphthalenedisulfonic acid, 4-hydroxy-, sodium salt (1:2) (CAS: 20349-39-7). Growth rate value was estimated to be 108.77 mg/l for Daphnia magna for 48 hrs duration. It was concluded that 2,7-Naphthalenedisulfonic acid, 4-hydroxy-, sodium salt (1:2) (CAS: 20349-39-7) was likely to be not toxic to aquatic algae and can be cosidered as "not classified" as per the clasisifcation 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 to invertebrate was predicted 2,7-Naphthalenedisulfonic acid, 4-hydroxy-, sodium salt (1:2) (CAS: 20349-39-7). Growth rate value was estimated to be 108.77 mg/l for Daphnia magna for 48 hrs duration. It was concluded that 2,7-Naphthalenedisulfonic acid, 4-hydroxy-, sodium salt (1:2) (CAS: 20349-39-7) was likely to be not toxic to aquatic algae and can be cosidered as "not classified" as per the clasisifcation 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 to invertebrate was predicted 2,7-Naphthalenedisulfonic acid, 4-hydroxy-, sodium salt (1:2) (CAS: 20349-39-7). Growth rate value was estimated to be 108.77 mg/l for Daphnia magna for 48 hrs duration. It was concluded that 2,7-Naphthalenedisulfonic acid, 4-hydroxy-, sodium salt (1:2) (CAS: 20349-39-7) was likely to be not toxic to aquatic algae and can be cosidered as "not classified" as per the clasisifcation for aquatic environment.

Key value for chemical safety assessment

EC50 for freshwater algae:

108.77 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 2,7-Naphthalenedisulfonic acid, 4-hydroxy-, sodium salt (1:2) (CAS: 20349-39-7) 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 invertebrate was predicted 2,7-Naphthalenedisulfonic acid, 4-hydroxy-, sodium salt (1:2) (CAS: 20349-39-7). Growth rate value was estimated to be 108.77 mg/l for Daphnia magna for 48 hrs duration. It was concluded that 2,7-Naphthalenedisulfonic acid, 4-hydroxy-, sodium salt (1:2) (CAS: 20349-39-7) was likely to be not toxic to aquatic algae and can be cosidered as "not classified" as per the clasisifcation for aquatic environment.

The predicted for the target chemical is supported by the experimental study ofstructurally similar read acrossdisodium 6-hydroxy-5-[(4-sulfonatophenyl)diazenyl]naphthalene-2-sulfonate (CAS: 2783 -94 -0) from the standard experimental report ABITEC 2016, suggests that the

Freshwater algal growth inhibition test was carried out on Desmodesmus subspicatus with the substancedisodium 6-hydroxy-5-[(4-sulfonatophenyl)diazenyl]naphthalene-2-sulfonateaccording to OECD Guideline 201.

The test substance was dissolved in DMSO and tested at the concentrations 0, 17, 30, 55, 100 and 185 mg/L. Effects on the growth rate of the organism were studied.

The median effective concentration (EC50) for the test substance,disodium 6-hydroxy-5-[(4-sulfonatophenyl)diazenyl]naphthalene-2-sulfonate, in Desmodesmus subspicatus was determined to be 113.2 mg/L.

This value indicates that the substance is not likely to be hazardous to aquatic algae as per the CLP criteria.

Further it is supported by the another structurally similar read acrossdisodium 5-acetamido-4-hydroxy-3-(phenyldiazenyl)naphthalene-2,7-disulfonate (CAS: 3734-67-6) study from ABITEC 2016, also 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 as “CSN 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 thedisodium 5-acetamido-4-hydroxy-3-(phenyldiazenyl)naphthalene-2,7-disulfonate (CAS: 3734-67-6) is not toxic to the aquatic algae and can be considered as "not classified" as per the classification criteria.

Thus based on the effect concentrations which is in the range 108.77 mg/L to 285.8 mg/l give the conclusion that test substance 2,7-Naphthalenedisulfonic acid, 4-hydroxy-, sodium salt (1:2) (CAS: 20349-39-7) was 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.