Sodium 3-(p-anilinophenylazo)benzenesulphonate

Endpoint summary

Description of key information

Short-term toxicity to fish

Based on nominal concentrations, experimental median lethal Concentrations [LC-50 (96 h)] for sodium 3-[(4-anilinophenyl)diazenyl]benzenesulfonate CAS No.587-98-4 on Zebra fish (Danio rerio) was determined to be 25 mg/L.

This value indicates that the Sodium 3-(p-anilinophenylazo)benzenesulphonate is toxic to fish and can be considered as "aquatic chronic 3" under CLP regulation.

 

Short-term toxicity to aquatic invertebrates

Using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and consideringthe 5 closest read across substances, the short term toxicity on aquatic invertebrates was predictedfor Sodium 3-(p-anilinophenylazo)benzenesulphonate (CAS 587 -98 -4). Effect concentration i.e EC50 value was estimated to be 6.55 mg/l for Daphnia magna for 48 hrs duration. Based on the effect value,Sodium 3-(p-anilinophenylazo)benzenesulphonate (CAS 587 -98 -4) was likely to be toxic to aquatic invertebrates, hence it can be considered to be“aquatic chronic 2”as per the CLP classification criteria for aquatic environment.

Toxicity to aquatic algae and cyanobacteria

After 72 hours of exposure to test item Sodium 3-(p-anilinophenylazo)benzenesulphonate (CAS No.587-98-4) to various nominal test concentrations, EC50 was found to be 7.9267 mg/l graphically and through probit analysis.

Thus, it was concluded that the Sodium 3-(p-anilinophenylazo)benzenesulphonate (Cas no. 587-98-4) is toxic to aquatic algae, hence it can be considered to be classified as Aquatic chronic 2 as per the CLP classification criteria for aquatic environment.

Toxicity to microorganisms:

The IC50 value (concentration for 50% inhibition of respiration rate) for the test chemical sodium 3-[(4-anilinophenyl)diazenyl]benzenesulfonate on activated sludge (aerobic bacteria) is determined to be >100 mg/L after 3 hrs of exposure.

Additional information

Short-term toxicity to fish

Two experimental studies were reviewed for short term fish endpoint of test substanceSodium 3-(p-anilinophenylazo)benzenesulphonate (CAS 587 -98 -4) which are summarised as follows.

In a key study, Fish Acute Toxicity test was conducted according to OECD Guideline 203 for sodium 3-[(4-anilinophenyl)diazenyl]benzenesulfonate. The nominal concentration selected for the experiment were1.56mg/L,3.125mg/L,6.25mg/L,12.5mg/L,25mg/Land Zebra fish(Danio rerio)were exposed to these concentration for 96 hours.The fishes were moving slowly as compared to control. No mortalities were found in the control aquaria. The lethal concentrations LC50 was found to be 25 mg/L.

Supporting study obtained from abstract of Journal for Nature Conservation. 1 (2): 155-157, 1989 indicates that the Channa punctate were exposed to the Sodium 3-(p-anilinophenylazo)benzenesulphonate preferably for a period of 96 hours. 50 % Mortalities of the fish (LC50) were determined. On the basis of 50% mortality the LC50 value is determined to be 1.5 mg/l.

Thus, based on the available effect concentrations from key study which is 25 mg/l for target it can be concludedn that test substance Sodium 3-(p-anilinophenylazo)benzenesulphonate (CAS 587 -98 -4) was likely to be toxic to fish, hence it can be considered to be“aquatic chronic 3”as per the CLP regulation.

Short-term toxicity to aquatic invertebrates

Four studies including predicted data from validated tools and experimental data from peer reviewedjournal and authorative database for short term aquatic invertebrate’s endpoint of test chemical Sodium 3-(p-anilinophenylazo)benzenesulphonate (CAS 587 -98 -4) with relevant read across which is close to target using log Kow as primary descriptor were summarised as follows:

 

Using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the 5 closest read across substances, the short term toxicity on aquatic invertebrates was predicted for Sodium 3-(p-anilinophenylazo)benzenesulphonate (CAS 587 -98 -4). Effect concentration i.e EC50 value was estimated to be 6.55 mg/l for Daphnia magna for 48 hrs duration. Based on the effect value, Sodium 3-(p-anilinophenylazo)benzenesulphonate (CAS 587 -98 -4) was likely to be toxic to aquatic invertebrates.

 

Similar prediction by Using battery model of Danish QSAR, on the basis of similarity of structure to chemicals for which the aquatic toxicity has been previously measured by structure-activity relationships (SARs) program suggest the LC50 value for short term toxicity to aquatic invertebrates was predictedthe toxicity of Sodium 3-(p-anilinophenylazo)benzenesulphonate EC50 estimated to be 2.52 mg/l to Daphnia magna when exposed for 48h.

 

Above both predicted results of target assist by experimental result of read across chemical Fluometuron (Cas no.2164-17-2) fromsecondary source EPA Office of Pesticides Program Databasewhich suggest the Short-term toxicity to aquatic invertebrates test was carried out to study the effects of Fluometuron on Americamysis bahia under flow through and saltwater conditions. Mortality effect were measured. The Lethal concentration (LC50) for Americamysis bahia when exposed to Fluometuron for 96 h is 6.8 mg/l.

Thus based on the all available effect concentrations which is in the range of 2.52 mg/l to 6.8 mg/l for target and read across chemicals and by applying weight of evidence approach it can be concluded that test substance Sodium 3-(p-anilinophenylazo)benzenesulphonate (Cas No. 587 -98 -4) is toxic to aquatic invertebrates, hence it can be considered classified under Aquatic chronic category 2 as per the CLP regulation.

Toxicity to aquatic algae and cyanobacteria

Four studies,considered as key and supporting studies,including predicted data from validated tools and experimental datafor toxicity to aquatic algae endpoint of test chemical Sodium 3-(p-anilinophenylazo)benzenesulphonate (CAS 587 -98 -4) with relevant read across which is close to target using log Kow as primary descriptor were summarised as follows:

 

In a key study, the effect of test item Sodium 3-(p-anilinophenylazo)benzenesulphonate, CAS No. 587-98-4 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 0.5 mg/L,1 mg/L,2 mg/L,4 mg/L,8 mg/L,16 mg/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 7.9267 mg/L.

 

Supporting data included prediction for target by Danish QSAR database, Using Battery algorithm model of Danish QSAR, the toxicity of Sodium 3-(p-anilinophenylazo)benzenesulphonate. EC50 was estimated to be 2.64 mg/l to Pseudokirchneriella s. at 72h.

 

Above experimental and predicted results for target assisted by experimental data of read across chemical 2-[({[(4,6-dimethoxypyrimidin-2-yl)carbamoyl]amino}sulfonyl)amino]-N,N-dimethylbenzamide) (Cas no.213464-77-8) fromEPA Office of Pesticides Program Databaseindidcates that the Effective concentration to 50% of Anabaena flosaquae is 3.8 mg/L.Population (Abundance) as effect of measurement.

 

One another read acrossN'(3,4Dichlorophenyl) N,Ndimethylurea (Diuron)(Cas No. 330 -54 -1) from Science of the Total Environment.463/464:469-477,suggest the50% Effective concentration to Sellaphora minima for Diuron is 2.606 mg/L when exposed for 96 hrs. It can be concluded that the Diuron is toxic to aquatic algae.

 

Thus based on the effect concentration from key study which is 7.9267mg/l gives the conclusion that test substance Sodium 3-(p-anilinophenylazo)benzenesulphonate (CAS 587 -98 -4) is toxic to aquatic algae at environmentally relevant concentrations and can be considered to be“aquatic chronic 2”as per the CLP classification criteria.

Toxicity to microorganisms:

A screening method based on the measurement of the respiration rate of activated sludge for assessing the possible inhibitory effect of dyestuffs on aerobic waste-water bacteria. The test principle involves measuring the respiration rate of an activated sludge and comparing it with the respiration rate of the same activated sludge under identical conditions, but in the presence of the chemical under test. The test was carried out in activated sludge respiration rate apparatus with constant 20 ± 2°C and pH about 7-8. The test concentration used was 100 mg/l. OECD recommended synthetic sewage was used as feed, while activated sludge was obtained from a sewage works treating predominantly domestic sewage or from a sewage works treating predominantly industrial waste water. The respiration rate of an activated sludge and the respiration rate of activated sludge with test chemical were noted down. In order to calculate the inhibitory effect of a particular chemical at 100 mg/l test concentration its respiration rate is expressed as a percentage of the mean of the two control respiration rates. For those chemicals whose respiration rate is at least 80% of the control, the IC50 (concentration for 50% inhibition of respiration rate) is recorded as >100 mg/l.

Thus, IC50 value (concentration for 50% inhibition of respiration rate) for the test chemical sodium 3-[(4-anilinophenyl)diazenyl]benzenesulfonate on activated sludge (aerobic bacteria) is determined to be >100 mg/L after 3 hrs of exposure. This value indicates that the test substance is not that toxic to microorganisms.