4-[(5-amino-3-methyl-1-phenyl-1H-pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acid

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: 4-[(5-amino-3-methyl-1-phenyl-1H-pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acid / Acid Yellow 49
- IUPAC name: 4-[(5-amino-3-methyl-1-phenyl-1H-pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acid
- Molecular formula: C16H13Cl2N5O3S
- Molecular weight: 426.283 g/mole
- Smiles :n1(c2ccccc2)c(c(\N=N\c2c(cc(S(O)(=O)=O)c(c2)Cl)Cl)c(n1)C)N
- Inchl: 1S/C16H13Cl2N5O3S/c1-9-15(16(19)23(22-9)10-5-3-2-4-6-10)21-20-13-7-12(18)14(8-11(13)17)27(24,25)26/h2-8H,19H2,1H3,(H,24,25,26)/b21-20+
- Substance type: Organic
- Physical state: Solid powder (yellow)

Analytical monitoring:

not specified

Vehicle:

not specified

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Test type:

static

Water media type:

freshwater

Total exposure duration:

72 h

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

121.927 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" or "c" )  and "d" )  and "e" )  and ("f" and ( not "g") )  )  and "h" )  and ("i" and ( not "j") )  )  and ("k" and "l" )  )

Domain logical expression index: "a"

Referential boundary: The target chemical should be classified as Acid moiety OR Anilines (Unhindered) OR Pyrazoles/Pyrroles by Aquatic toxicity classification by ECOSAR ONLY

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as SNAr OR SNAr >> Nucleophilic aromatic substitution OR SNAr >> Nucleophilic aromatic substitution >> Activated halo-benzenes by Protein binding by OECD ONLY

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as SN1 OR SN1 >> Nitrenium Ion formation OR SN1 >> Nitrenium Ion formation >> Primary (unsaturated) heterocyclic amine OR SN1 >> Nitrenium Ion formation >> Unsaturated heterocyclic azo by DNA binding by OECD ONLY

Domain logical expression index: "d"

Referential boundary: The target chemical should be classified as Class 3 (unspecific reactivity) by Acute aquatic toxicity classification by Verhaar (Modified) ONLY

Domain logical expression index: "e"

Referential boundary: The target chemical should be classified as Acid moiety AND Anilines (Unhindered) AND Pyrazoles/Pyrroles by Aquatic toxicity classification by ECOSAR ONLY

Domain logical expression index: "f"

Referential boundary: The target chemical should be classified as Halogens AND Non-Metals by Groups of elements

Domain logical expression index: "g"

Referential boundary: The target chemical should be classified as Transition Metals by Groups of elements

Domain logical expression index: "h"

Referential boundary: The target chemical should be classified as Bioavailable by Lipinski Rule Oasis ONLY

Domain logical expression index: "i"

Referential boundary: The target chemical should be classified as Aliphatic Amine, primary AND Aryl AND Aryl halide AND Azo AND Overlapping groups AND Pyrazole AND Sulfonic acid by Organic Functional groups (nested)

Domain logical expression index: "j"

Referential boundary: The target chemical should be classified as Nitrobenzene by Organic Functional groups (nested)

Domain logical expression index: "k"

Parametric boundary:The target chemical should have a value of log Kow which is >= -2.08

Domain logical expression index: "l"

Parametric boundary:The target chemical should have a value of log Kow which is <= 2.04

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 aquatic algae was predicted 4-[(5-amino-3-methyl-1-phenyl-1H-pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acid (CAS: 12239-15-5). EC50 growth rate was estimated to be 121.927 mg/l for Desmodesmus subspicatus for 72 hrs duration. It was concluded that 4-[(5-amino-3-methyl-1-phenyl-1H-pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acid (CAS: 12239-15-5) was likely to be not toxic to aquatic algae.

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 aquatic algae was predicted 4-[(5-amino-3-methyl-1-phenyl-1H-pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acid (CAS: 12239-15-5). EC50 growth rate was estimated to be 121.927 mg/l for Desmodesmus subspicatus for 72 hrs duration. It was concluded that 4-[(5-amino-3-methyl-1-phenyl-1H-pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acid (CAS: 12239-15-5) was likely to be not toxic to aquatic algae.

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 aquatic algae was predicted 4-[(5-amino-3-methyl-1-phenyl-1H-pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acid (CAS: 12239-15-5). EC50 growth rate was estimated to be 121.927 mg/l for Desmodesmus subspicatus for 72 hrs duration. It was concluded that 4-[(5-amino-3-methyl-1-phenyl-1H-pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acid (CAS: 12239-15-5) was likely to be not toxic to aquatic algae.

Key value for chemical safety assessment

EC50 for freshwater algae:

121.927 mg/L

Additional information

Following studies of target chemical and structurally similar read across includes predicted data and experimental data to conclude the toxicity extent of 4-[(5-amino-3-methyl-1-phenyl-1H-pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acid (CAS: 12239-15-5) 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 aquatic algae was predicted 4-[(5-amino-3-methyl-1-phenyl-1H-pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acid (CAS: 12239-15-5). EC50 growth rate was estimated to be 121.927 mg/l for Desmodesmus subspicatus for 72 hrs duration. It was concluded that 4-[(5-amino-3-methyl-1-phenyl-1H-pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acid (CAS: 12239-15-5) was likely to be not toxic to aquatic algae.

The above predicted data of target chemical is supported by the experimental study of structurally similar read across Ammonium 3-amino-2,5-dichlorobenzoate (CAS: 1076-46-6) from the publication Hyacinth control journal 1972, suggests that the Toxicity to aquatic algae and cyanobacteria test was carried out to study the effects of Ammonium 3-amino-2,5-dichlorobenzoate on aquatic algae. Decreasing trend ofPopulation growth rate was measured during the test.

Effective concentration to 50% of Dunaliella tertiolecta when exposed to Ammonium 3-amino-2,5-dichlorobenzoate for 10 days is 4000 mg/L. It can be concluded from the value that the Ammonium 3-amino-2,5-dichlorobenzoate (CAS: 1076-46-6) is not toxic to the aquatic algaecan be considered as “not classified” as per the classification criteria for aquatic environment.

Another supporting experimental study for the structurally similar read across 4 -aminobenzenesulfonic acid (CAS no. 121 -57 -3) from the High Production Volume (HPV) Challenge Program 2016, also suggests that the Short term toxicity to Scenedesmus subspicatus(green algae) study was carried out for 72 hrs. The study was performed according to other guideline DIN 38412 Part 9, 1992. The study was based on the effects of the test compound 4 -aminobenzenesulfonic acid (CAS no. 121 -57 -3) onScenedesmus subspicatus(green algae) in a static fresh water system. Scenedesmus subspicatuswas used as a test organism. Based on effect on growth rate of the test organismScenedesmus subspicatus(green algae), the 72 hr EC10 and EC50 value was determined to be 2.7 and 375 mg/l, respectively. Thus, based on the EC50 value, it can be concluded that the substance 4 -aminobenzenesulfonic acid can be considered as non-toxic to aquatic organisms and thus cannot be classified as hazardous as per the CLP classification criteria.

Thus based on the effect concentrations which is in the range 121.927 mg/l to 4000 mg/l give the conclusion that test substance 4-[(5-amino-3-methyl-1-phenyl-1H-pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acid (CAS: 12239-15-5) was likely to be not toxic to aquatic algae at environmentally relevant concentrations and can be considered to be “not classified” as per the CLP classification criteria.