2-amino-5-hydroxynaphthalene-1,7-disulphonic acid

Endpoint summary

Description of key information

Short term toxicity to aquatic invertebrates:

Based on using the OECD QSAR toolbox version 3.4 with log kow as the primary descriptor and considering the five closest read across substances, toxicity on Daphnia magna predicted for 2-amino-5-hydroxynaphthalene-1,7-disulfonic acid (6535 -70 -2). The EC50 value was estimated to be 116.755 mg/l when 2-amino-5 -hydroxynaphthalene- 1,7-disulfonic acid exposed to Daphnia magna for 48 hrs. Thus the chemical can be consider to be not toxic to the growth of aquatic invertebrates.

Short term toxicity to aquatic algae:

Using the OECD QSAR toolbox version 3.4 with log kow as the primary descriptor and considering the five closest read across substances, the short term toxicity on aquatic algae and cyanobacteria was predicted for target substance 2-amino-5-hydroxynaphthalene-1,7-disulfonic acid (CAS no. 6535 -70 -2). EC50 value was estimated to be 134.567 mg/l for Desmodesmus subspicatus (previous name: Scenedesmus subspicatus) for 72 h duration. Based on this value it can be concluded that the substance 2-amino-5-hydroxynaphthalene -1,7-disulfonic acid is considered to be non-toxic to aquatic environment and can be considered to be not classified as per the CLP classification criteria.

Additional information

Summarized result of toxicity of 2-amino-5-hydroxynaphthalene-1,7-disulfonic acid (6535 -70 -2) on the growth and other activity of aquatic invertebrates, algae and cyanobacteria by considering the data for target as well as RA chemical which was selected on the basis of log Kow as the primary descriptor are as follows:  

Short term toxicity to aquatic invertebrates:

Various predicted data for the target compound 2-amino-5-hydroxynaphthalene-1,7-disulfonic acid (6535 -70 -2) and supporting weight of evidence studies for its closest read across substance with log Kow as the primary descriptor were reviewed for the toxicity on the invertebrates end point which are summarized as below:

 

In a prediction done by SSS (2017), Based on using the OECD QSAR toolbox version 3.4 with log kow as the primary descriptor and considering the five closest read across substances, toxicity on Daphnia magna predicted for 2-amino-5-hydroxynaphthalene-1,7-disulfonic acid (6535 -70 -2). The EC50 value was estimated to be 116.755 mg/l when 2-amino-5 -hydroxynaphthalene- 1,7-disulfonic acid exposed to Daphnia magna for 48 hrs. Thus the chemical can be consider to be not toxic to the growth of aquatic invertebrates.

 

Similarly in a supporting weight of evidence study from ABITEC report 2016 for read across chemical 4-amino-5-hydroxynaphthalene-1,7-disulphonic acid (130-23-4) toxicity experiment was conducted for evaluating the effect of read across substance. Determination of the inhibition of the mobility of daphnids was carried out with the substance 4-amino-5-hydroxynaphthalene-1,7-disulphonic acid according to OECD Guideline 202. The test substance was tested at the concentrations of 0 for 3 controls and 5, 10, 25, 100, 200 mg/L for test chemical. Effects on immobilisation were observed for 48 hours. The median effective concentration (EC50) for the test substance, 4-amino-5-hydroxynaphthalene-1,7-disulphonic acid, in Daphnia magna was determined to be 500 mg/L for immobilisation effects. This value indicates that the substance 4-amino-5-hydroxynaphthalene-1,7-disulphonic acid is likely to be non-hazardous to aquatic invertebrates and cannot be classified as toxic as per the CLP criteria.

 

Similarly in a second supporting weight of evidence study from ABITEC report 2016 for read across chemical 5-amino-4-hydroxy-3-(phenylazo)naphthalene-2,7- disulphonate (3567-66-6), Determination of the inhibition of the mobility of daphnids was carried out with the substance 5-amino-4-hydroxy-3-(phenylazo)naphthalene -2,7-disulphonate according to OECD Guideline 202. The test substance was tested at the limit concentrations of 100 mg/l for test chemical. Effects on immobilisation were observed for 48 hours. The NOEC for the test substance, disodium 5-amino-4-hydroxy-3-(phenylazo)naphthalene-2,7-disulphonate, in Daphnia magna was determined to be 100 mg/L on the basis of mobility inhibition effects in a 48 hour study. This value indicates that the substance 5-amino-4-hydroxy-3-(phenylazo) naphthalene-2,7-disulphonate is likely to be non-hazardous to aquatic invertebrates and cannot be classified as toxic as per the CLP criteria.

 

On the basis of above results for target chemical 2-amino-5-hydroxynaphthalene-1,7-disulfonic acid (6535 -70 -2) (from OECD QSAR toolbox version 3.4, 2017) and for its read across substance from ABITEC report, it can be concluded that the test substance 2-amino-5-hydroxynaphthalene-1,7-disulfonic acid is not toxic and can be consider to be not classified as toxic as per the CLP classification criteria.

Short term toxicity to aquatic algae:

Various predicted data for the target compound 2-amino-5-hydroxynaphthalene-1,7-disulfonic acid (6535 -70 -2) and supporting weight of evidence studies for its closest read across substance with log Kow as the primary descriptor were reviewed for the toxicity on the algae end point which are summarized as below:

In a prediction done by SSS (2017), Using the OECD QSAR toolbox version 3.4 with log kow as the primary descriptor and considering the five closest read across substances, the short term toxicity on aquatic algae and cyanobacteria was predicted for target substance 2-amino-5-hydroxynaphthalene-1,7-disulfonic acid (CAS no. 6535 -70 -2). EC50 value was estimated to be 134.567 mg/l for Desmodesmus subspicatus (previous name: Scenedesmus subspicatus) for 72 h duration. Based on this value it can be concluded that the substance 2-amino-5-hydroxynaphthalene -1,7-disulfonic acid is considered to be non-toxic to aquatic environment and can be considered to be not classified as per the CLP classification criteria.

 

In second prediction using the Danish QSAR, 2017, Based on the prediction done 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 substance 2-amino-5-hydroxynaphthalene-1,7-disulfonic acid (CAS: 6535 -70 -2). 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 2-amino-5-hydroxynaphthalene -1,7- disulfonic acid is estimated to be 23005 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 2-amino-5-hydroxynaphthalene-1,7-disulfonic acid 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 a supporting weight of evidence study from ABITEC report 2016 for read across chemical 4-amino-5-hydroxynaphthalene-1,7-disulphonic acid (130-23-4) toxicity experiment was conducted for evaluating the effect of read across substance. Freshwater algal growth inhibition test was carried out on Desmodesmus subspicatus with the substance 4-amino-5-hydroxynaphthalene-1,7-disulphonic acid 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, 4-amino-5-hydroxynaphthalene-1,7-disulphonic acid, in Desmodesmus subspicatus was determined to be 129.4 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 4-amino-5-hydroxynaphthalene-1,7-disulphonic acid does not exhibit toxicity to aquatic algae (Desmodesmus subspicatus) and not classified as toxic as per the CLP classification criteria.

 

Similarly for the same read across chemical, toxicity study was conducted and reported from UERL lab, 2016, The effect of test item 4-amino-5-hydroxynaphthalene -1,7-disulphonic acid, CAS No. 130-23-4 was studied on the growth of fresh water green alga Chlorella vulgaris. The study was conducted following OECD guideline 201- Alga, growth inhibition test. The test concentration chosen for the study were 6.25mg/l, 12.5mg/l, 25mg/l, 50mg/l, 100mg/l and 200mg/l. The test concentrations were prepared using stock solution of the test item using mineral media. The green alga was exposed to the test concentration for a period of 72 hours to observe average specific growth rate and % growth inhibition under the effect of the test item. EC50 calculated graphically through probit analysis was observed to be >200mg/l. Thus, based on the EC50 value, test substance 4-amino-5-hydroxynaphthalene-1,7-disulphonic acid can be classified as not hazardous and nontoxic as per the criteria of CLP regulation.

 

Similarly in a third supporting weight of evidence study from ABITEC report 2016 for read across chemical 5-amino-4-hydroxy-3-(phenylazo)naphthalene -2,7- disulphonate (3567-66-6), Freshwater algal growth inhibition test was carried out on Desmodesmus subspicatus with the substance disodium 5-amino-4-hydroxy- 3-(phenylazo)naphthalene -2,7-disulphonate according to OECD Guideline 201. The test substance was dissolved in OECD growth medium and tested at the concentrations 0, 0, 12.5, 25, 100, 200 mg/L. Effects on the growth rate of the organism were studied. The median effective concentration (ErC50) for the test substance, disodium 5-amino-4-hydroxy- 3-(phenylazo)naphthalene-2,7-disulphonate, in Desmodesmus subspicatus was determined to be 330.2 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 disodium 5-amino-4-hydroxy-3- (phenylazo) naphthalene-2,7-disulphonate does not exhibit toxicity to aquatic algae (Desmodesmus subspicatus) and not classified as toxic as per the CLP classification criteria.

 

On the basis of above results for target chemical 2-amino-5-hydroxynaphthalene-1,7-disulfonic acid (6535 -70 -2) (from OECD QSAR toolbox version 3.4, and Danish QSAR, 2017) and for its read across substance from ABITEC report and UERL, it can be concluded that the test substance 2-amino-5-hydroxynaphthalene-1,7- disulfonic acid is not toxic and can be consider to be not classified as toxic as per the CLP classification criteria.

Thus based on the data for short term toxicity to invertebrates and algae, database it can be concluded that the test substance 2-amino-5-hydroxynaphthalene -1,7-disulfonic acid is not toxic and can be consider to be not classified as per the CLP classification criteria.