p-[4,5-dihydro-4-[[2-methoxy-5-methyl-4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-3-methyl-5-oxo-1H-pyrazol-1-yl]benzenesulphonic 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:

OECD Guideline 201 (Alga, Growth Inhibition Test)

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: p-[4,5-dihydro-4-[[2-methoxy-5-methyl-4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-3-methyl-5-oxo-1H-pyrazol-1-yl] benzenesulphonic acid or Reactive Yellow 15 free acid
- IUPAC name: 4-{4-[(E)-2-{2-methoxy-5-methyl-4-[2-(sulfooxy)ethanesulfonyl]phenyl}diazen-1-yl]-3-methyl-5-oxo-4,5-dihydro-1H-pyrazol-1-yl} benzene-1-sulfonic acid
- Molecular formula: C20H22N4O11S3
- Molecular weight: 590.609 g/mol
- Smiles : O=S(=O)(OCCS(=O)(=O)c1c(cc(\N=N\[C@@H]2C(=O)N(c3ccc(S(=O)(=O)O)cc3)N=C2C)c(OC)c1)C)O
- Inchl: 1S/C20H22N4O11S3/c1-12-10-16(17(34-3)11-18(12)36(26,27)9-8-35-38(31,32)33)21-22-19-13(2)23-24(20(19)25)14-4-6-15(7-5-14)37 (28,29)30/h4-7,10-11,19H,8-9H2,1-3H3,(H,28,29,30)(H,31,32,33)/b22-21+
- Substance type: Organic
- Physical state: Solid

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.:

398.494 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" or "d" or "e" )  and ("f" and ( not "g") )  )  and "h" )  and "i" )  and ("j" and ( not "k") )  )  and ("l" and ( not "m") )  )  and ("n" and "o" )  )

Domain logical expression index: "a"

Referential boundary: The target chemical should be classified as Vinyl Sulfones by US-EPA New Chemical Categories

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as Schiff base formation AND Schiff base formation >> Pyrazolones and Pyrazolidinones derivatives AND Schiff base formation >> Pyrazolones and Pyrazolidinones derivatives >> Pyrazolones and Pyrazolidinones  by Protein binding by OASIS v1.3

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as Acid moiety OR Amides OR Hydrazines by Aquatic toxicity classification by ECOSAR ONLY

Domain logical expression index: "d"

Referential boundary: The target chemical should be classified as Acylation OR Acylation >> Direct Acylation Involving a Leaving group OR Acylation >> Direct Acylation Involving a Leaving group >> Acetates OR SN2 OR SN2 >> SN2 reaction at sp3 carbon atom OR SN2 >> SN2 reaction at sp3 carbon atom >> Alkyl diazo by Protein binding by OECD ONLY

Domain logical expression index: "e"

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

Domain logical expression index: "f"

Referential boundary: The target chemical should be classified as No alert found by DNA binding by OASIS v.1.3

Domain logical expression index: "g"

Referential boundary: The target chemical should be classified as AN2 OR AN2 >> Michael-type addition on alpha, beta-unsaturated carbonyl compounds OR AN2 >> Michael-type addition on alpha, beta-unsaturated carbonyl compounds >> Four- and Five-Membered Lactones OR AN2 >> Shiff base formation after aldehyde release OR AN2 >> Shiff base formation after aldehyde release >> Specific Acetate Esters OR Non-covalent interaction OR Non-covalent interaction >> DNA intercalation OR Non-covalent interaction >> DNA intercalation >> DNA Intercalators with Carboxamide Side Chain OR SN1 OR SN1 >> Nucleophilic attack after carbenium ion formation OR SN1 >> Nucleophilic attack after carbenium ion formation >> Specific Acetate Esters OR SN2 OR SN2 >> Acylation OR SN2 >> Acylation >> Specific Acetate Esters OR SN2 >> Alkylation, ring opening SN2 reaction OR SN2 >> Alkylation, ring opening SN2 reaction >> Four- and Five-Membered Lactones OR SN2 >> Nucleophilic substitution at sp3 Carbon atom OR SN2 >> Nucleophilic substitution at sp3 Carbon atom >> Specific Acetate Esters by DNA binding by OASIS v.1.3

Domain logical expression index: "h"

Referential boundary: The target chemical should be classified as Class 5 (Not possible to classify according to these rules) by Acute aquatic toxicity classification by Verhaar (Modified) ONLY

Domain logical expression index: "i"

Referential boundary: The target chemical should be classified as Reactive unspecified by Acute aquatic toxicity MOA by OASIS ONLY

Domain logical expression index: "j"

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

Domain logical expression index: "k"

Referential boundary: The target chemical should be classified as Alkaline Earth OR Halogens by Groups of elements

Domain logical expression index: "l"

Referential boundary: The target chemical should be classified as Not categorized by Repeated dose (HESS)

Domain logical expression index: "m"

Referential boundary: The target chemical should be classified as Amineptine (Hepatotoxicity) Alert OR Thiocarbamates/Sulfides (Hepatotoxicity) No rank by Repeated dose (HESS)

Domain logical expression index: "n"

Parametric boundary:The target chemical should have a value of log Kow which is >= -3.31

Domain logical expression index: "o"

Parametric boundary:The target chemical should have a value of log Kow which is <= 0.384

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 algae was predicted 4-{4-[(2-methoxy-5-methyl-4-{[2-(sulfooxy)ethyl]sulfonyl}phenyl)diazenyl]-3-methyl-5-oxo-4,5-dihydro... (CAS: 60958-41-0). EC50 growth rate value was estimated to be 398.494 mg/l for Desmodesmus subspicatus for 72 hrs duration. It was concluded that 4-{4-[(2-methoxy-5-methyl-4-{[2-(sulfooxy)ethyl]sulfonyl}phenyl)diazenyl]-3-methyl-5-oxo-4,5-dihydro... (CAS: 60958-41-0) was likely to be not toxic to 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 algae was predicted 4-{4-[(2-methoxy-5-methyl-4-{[2-(sulfooxy)ethyl]sulfonyl}phenyl)diazenyl]-3-methyl-5-oxo-4,5-dihydro... (CAS: 60958-41-0). EC50 growth rate value was estimated to be 398.494 mg/l for Desmodesmus subspicatus for 72 hrs duration. It was concluded that 4-{4-[(2-methoxy-5-methyl-4-{[2-(sulfooxy)ethyl]sulfonyl}phenyl)diazenyl]-3-methyl-5-oxo-4,5-dihydro... (CAS: 60958-41-0) was likely to be not toxic to 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 algae was predicted 4-{4-[(2-methoxy-5-methyl-4-{[2-(sulfooxy)ethyl]sulfonyl}phenyl)diazenyl]-3-methyl-5-oxo-4,5-dihydro... (CAS: 60958-41-0). EC50 growth rate value was estimated to be 398.494 mg/l for Desmodesmus subspicatus for 72 hrs duration. It was concluded that 4-{4-[(2-methoxy-5-methyl-4-{[2-(sulfooxy)ethyl]sulfonyl}phenyl)diazenyl]-3-methyl-5-oxo-4,5-dihydro... (CAS: 60958-41-0) was likely to be not toxic to algae.

Key value for chemical safety assessment

EC50 for freshwater algae:

398.494 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-{4-[(2-methoxy-5-methyl-4-{[2-(sulfooxy)ethyl]sulfonyl}phenyl)diazenyl]-3-methyl-5-oxo-4,5-dihydro... (CAS: 60958-41-0) towards 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 algae was predicted 4-{4-[(2-methoxy-5-methyl-4-{[2-(sulfooxy)ethyl]sulfonyl}phenyl)diazenyl]-3-methyl-5-oxo-4,5-dihydro... (CAS: 60958-41-0). EC50 growth rate value was estimated to be 398.494 mg/l for Desmodesmus subspicatus for 72 hrs duration. It was concluded that 4-{4-[(2-methoxy-5-methyl-4-{[2-(sulfooxy)ethyl]sulfonyl}phenyl)diazenyl]-3-methyl-5-oxo-4,5-dihydro... (CAS: 60958-41-0) was likely to be not toxic to algae.

The above predicted data of target chemical is supported by the experimental study of structurally similar read across Aluminium,6-hydroxy-5- [(2-methoxy-5-methyl-4-sul fophenyl)azo ]-2-naphthalenesulfonic acid complex (CAS: 68583-95-9) from the UERL lab 2016, suggests that the effect of test item aluminium, 6-hydroxy-5-[(2-methoxy-5-methyl-4-sulfophenyl)azo]-2-naphthalenesulfonic acid complex, CAS No. 68583-95-9 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, 200mg/L. The test solution was prepared in aseptic condition. The test item aluminium, 6-hydroxy-5-[(2-methoxy-5-methyl-4-sulfophenyl)azo]- 2-naphthalenesulfonic acid complex was prepared by adding 50 mg of test item in 250 ml of BBM to get the final concentration of 200 mg/L. This stock solution was kept for stirring for 24 hours and filter it to obtain a homogenous solution for the experiment. The test concentrations were chosen according to the available data of the test item. The concentrations chosen were set up to the water solubility limit. The remaining test solutions were prepared by dilution from the above stock solution. To have a better growth and visibility of cells, the initial of the culture was kept 1 X 104cells/ml.

The microscopic observations were noted down in each of the control vessel. All the cells appeared healthy, round and green throughout the study duration in the control. Also, the drift in pH in the control vessels did not increase by >1.5 units when observed on 72 hours as compared to 0 hours. The average pH drift observed in the control vessels was 0.1 units.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 136.57 mg/L.

Based on the EC50, it can be concluded that the chemical was nontoxic and can be consider to be not classified as toxic as per the CLP classification criteria.

Another supporting experimental study for the structurally similar read across 2,7-Naphthalenedisulfonic acid, 3-hydroxy-4-[(4-sulfo-1-naphthalenyl), sodium salt; Amaranth dye; trisodium 3-hydroxy-4-[(4-sulfonato-1-naphthyl)diazenyl]naphthalene-2,7-disulfonate (CAS: 915-67-3) from the ABITEC lab 2016, also suggests that the Freshwater algal growth inhibition test was carried out on Desmodesmus subspicatus with the substance 2,7-Naphthalenedi- sulfonic acid, 3-hydroxy-4-[(4-sulfo- 1-naphthal - enyl), sodium salt (Amaranth dye) according to OECD Guideline 201.

The test substance was dissolved in OECD growth medium and tested at the concentrations 0, 12.5, 25, 50, 100, 200 mg/L. Effects on the growth rate of the organism were studied.

The median effective concentration (ErC50) for the test substance, 2,7-Naphthalenedisulfonic acid, 3-hydroxy-4-[(4-sulfo-1- -naphthalenyl), sodium salt, in Desmodesmus subspicatus was determined to be 356.2 mg/L.

This value indicates that the substance is likely to be non-hazardous to aquatic algae and can not be classified as toxic as per the CLP criteria.

Thus based on the effect concentrations which is in the range 136.57 mg/l to 398.494 mg/l give the conclusion that test substance 4-{4-[(2-methoxy-5-methyl-4-{[2-(sulfooxy)ethyl]sulfonyl}phenyl)diazenyl]-3-methyl-5-oxo-4,5-dihydro... (CAS: 60958-41-0) 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.