Disodium 4-hydroxynaphthalene-2,7-disulphonate

Endpoint summary

Description of key information

Short-term toxicity to aquatic invertebrates

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). Intoxication value was estimated to be 163.785 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 invertebrate.

Toxicity to aquatic algae and cyanobacteria

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.

Additional information

Short-term toxicity to aquatic invertebrates

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 invertebrate 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). Intoxication value was estimated to be 163.785 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 invertebrate.

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

Determination of the inhibition of the mobility of daphnids was carried out with the substancedisodium 6-hydroxy-5-[(4-sulfonatophenyl)diazenyl]naphthalene-2-sulfonateaccording to OECD Guideline 202 for 48 hr under static condition.

The test substance was tested at the concentration 100 mg/L. 0% Daphnia were immobilised at the end of the test.

The median effective concentration (EC50) for the test substance,disodium 6-hydroxy-5-[(4-sulfonatophenyl)diazenyl]naphthalene-2-sulfonate, in Daphnia magna was determined to be > 100 mg/L for immobilisation effects.This value indicates that the substance is not likely to be hazardous to aquatic invertebrates as per the CLP criteria and is "not classified" .

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 thatAn acute immobilisation test was used to test how a range of concentrations of CAS 3734-67-6 exerts different degrees of toxic effects on the swimming capability of Daphnia magna under otherwise identical test conditions. The test was performed in close resemblance to OECD guideline 202 by ABITEC in Prague. The standardized protocol used to obtain the herein described results was by the testing laboratory referred to as“CSN EN ISO 6341”. The testing aim was to determine a EC50 after 48 hours of exposure to D. magna. Daphnids were exposed to CAS 3734-67-6 in 50 ml beakers in a volume of 25 ml of liquid solution containing both the chemical and media as specified in OECD 202. The beakers were placed in a temperature controlled room at 20±1 degrees Celsius. TheD. magna(age≤24) used for the test had been breed at ABITEC. The breeding stock ofD. magnaoriginated from University of Technology in Prague. The animals were exposed to medium (i.e.a beaker containing only medium) and/or the tested chemical during 48 hours (±1 hour). None of the exposed animal’s immobilization were affected by exposure to only medium. The nominal concentrations used were: 100 mg/L (limit test). There were 5 Daphnia per test vessels and 4 replicates per concentration. The pH in test vessels were 7.7-7.8 mg/L. The positive control/reference substance used in the tested showed an expected result and gave an EC50 that corresponded to previous exposures with this chemical in D. magna. The EC50 was defined as a concentration that immobilizes 50% of the exposed D. magna. Eight percent of immobilization in D. magna after 48 hours of exposure to 100 mg/L of CAS 3734-67-6 was observed. The EC8 was therefore estimated to be 100 mg/L.

Thus based on the effect concentrations which is in the range 100 mg/L to 163.785 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 invertebrate at environmentally relevant concentrations and applying weight of evidence approach it can be considered to be“not classified”as per the CLP classification criteria.

Toxicity to aquatic algae and cyanobacteria

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.