Sodium 6-amino-5-[[4-chloro-2-(trifluoromethyl)phenyl]azo]-4-hydroxynaphthalene-2-sulphonate

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:

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 was done using the OECD QSAR toolbox version 3.3.

GLP compliance:

not specified

Specific details on test material used for the study:

- Name: Sodium 6-amino-5-[[4-chloro-2-(trifluoromethyl)phenyl]azo]-4-hydroxynaphthalene-2-sulphonate
- Mol. formula: C17H10ClF3N3NaO4S
- Molecular Weight: 467.786 g/mole
- SMILES:Nc1ccc2cc(S(=O)(=O)O{-}.[Na]{+})cc(O)c2c1N=Nc1ccc(Cl)cc1C(F)(F)F
- InChI:1S/C17H11ClF3N3O4S.Na/c18-9-2-4-13(11(6-9)17(19,20)21)23-24-16-12(22)3-1-8-5-10(29(26,27)28)7-14(25)15(8)16;/h1-7,25H,22H2,(H,26,27,28);/q;+1/p-1/b24-23-;

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

Test temperature:

23 °C

pH:

7.94 to 8.01

Nominal and measured concentrations:

Estimated data

Reference substance (positive control):

not specified

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

144.5 mg/L

Nominal / measured:

estimated

Conc. based on:

not specified

Basis for effect:

growth rate

Remarks on result:

other: Other details not known

The prediction was based on dataset comprised from the following descriptors: EC50
Estimation method: Takes average value from the 7 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 ( not "i") )  )  and "j" )  and ("k" and ( not "l") )  )  and ("m" and ( not "n") )  )  and "o" )  and ("p" and "q" )  )

Domain logical expression index: "a"

Referential boundary: The target chemical should be classified as Anilines (Acute toxicity) by US-EPA New Chemical Categories

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as Non-covalent interaction AND Non-covalent interaction >> DNA intercalation AND Non-covalent interaction >> DNA intercalation >> Fused-Ring Primary Aromatic Amines AND Radical AND Radical >> Radical mechanism via ROS formation (indirect) AND Radical >> Radical mechanism via ROS formation (indirect) >> Fused-Ring Primary Aromatic Amines AND SN1 AND SN1 >> Nucleophilic attack after metabolic nitrenium ion formation AND SN1 >> Nucleophilic attack after metabolic nitrenium ion formation >> Fused-Ring Primary Aromatic Amines by DNA binding by OASIS v.1.3

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as SN1 AND SN1 >> Nitrenium Ion formation AND SN1 >> Nitrenium Ion formation >> Aromatic azo AND SN1 >> Nitrenium Ion formation >> Primary aromatic amine by DNA binding by OECD

Domain logical expression index: "d"

Referential boundary: The target chemical should be classified as Strong binder, NH2 group AND Strong binder, OH group by Estrogen Receptor Binding

Domain logical expression index: "e"

Referential boundary: The target chemical should be classified as Acid moiety AND Anilines (Unhindered) AND Phenol Amines AND Phenols AND Salt by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "f"

Referential boundary: The target chemical should be classified as Strong binder, NH2 group AND Strong binder, OH group by Estrogen Receptor Binding

Domain logical expression index: "g"

Referential boundary: The target chemical should be classified as Non binder, impaired OH or NH2 group by Estrogen Receptor Binding

Domain logical expression index: "h"

Referential boundary: The target chemical should be classified as Strong binder, NH2 group AND Strong binder, OH group by Estrogen Receptor Binding

Domain logical expression index: "i"

Referential boundary: The target chemical should be classified as Moderate binder, NH2 group by Estrogen Receptor Binding

Domain logical expression index: "j"

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: "k"

Referential boundary: The target chemical should be classified as Acid moiety AND Anilines (Unhindered) AND Phenol Amines AND Phenols AND Salt by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "l"

Referential boundary: The target chemical should be classified as Anilines (amino-para) by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "m"

Referential boundary: The target chemical should be classified as Acid moiety AND Anilines (Unhindered) AND Phenol Amines AND Phenols AND Salt by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "n"

Referential boundary: The target chemical should be classified as Esters by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "o"

Similarity boundary:Target: Nc1ccc2cc(S(=O)(=O)O{-}.[Na]{+})cc(O)c2c1N=Nc1ccc(Cl)cc1C(F)(F)F
Threshold=20%,
Dice(Atom centered fragments)
Atom type; Count H attached; Hybridization

Domain logical expression index: "p"

Parametric boundary:The target chemical should have a value of log Kow which is >= 0.288

Domain logical expression index: "q"

Parametric boundary:The target chemical should have a value of log Kow which is <= 1.8

Validity criteria fulfilled:

not specified

Conclusions:

Based on the growth rate inhibition the EC50 value was estimated to be 144.5 mg/l when Sodium 6-amino-5-[[4-chloro-2-(trifluoromethyl)phenyl]azo]-4-hydroxynaphthalene-2-sulphonate exposed to Desmodesmus subspicatus for 72 hrs.

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 seven closest read across substances, toxicity on Desmodesmus subspicatus (previous name: Scenedesmus subspicatus) predicted for Sodium 6-amino-5-[[4-chloro-2-(trifluoromethyl)phenyl]azo]-4-hydroxynaphthalene-2-sulphonate (57741-47-6). The EC50 value was estimated to be 144.5 mg/l when Sodium 6-amino-5-[[4-chloro-2-(trifluoromethyl)phenyl]azo]-4-hydroxynaphthalene-2-sulphonate exposed to Desmodesmus subspicatus for 72 hrs. Based on this value it can be concluded that the substance Sodium 6-amino-5-[[4-chloro-2-(trifluoromethyl) phenyl]azo]-4-hydroxynaphthalene-2-sulphonate (57741-47-6) is considered to be not toxic to aquatic environment and not classified as per the criteria mentioned in CLP regulation.   

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 seven closest read across substances, toxicity on Desmodesmus subspicatus (previous name: Scenedesmus subspicatus) predicted for Sodium 6-amino-5-[[4-chloro-2-(trifluoromethyl)phenyl]azo]-4-hydroxynaphthalene-2-sulphonate (57741-47-6). The EC50 value was estimated to be 144.5 mg/l when Sodium 6-amino-5-[[4-chloro-2-(trifluoromethyl)phenyl]azo]-4-hydroxynaphthalene-2-sulphonate exposed to Desmodesmus subspicatus for 72 hrs. Based on this value it can be concluded that the substance Sodium 6-amino-5-[[4-chloro-2-(trifluoromethyl) phenyl]azo]-4-hydroxynaphthalene-2-sulphonate (57741-47-6) is considered to be not toxic to aquatic environment and not classified as per the criteria mentioned in CLP regulation.   

Key value for chemical safety assessment

EC50 for freshwater algae:

144.5 mg/L

Additional information

Based on the various prediction data for the target chemical and experimental data for the read across chemical study have been reviewed to determine the toxic nature of Sodium 6-amino-5-[[4-chloro-2-(trifluoromethyl)phenyl]azo]-4-hydroxynaphthalene-2-sulphonate (57741-47-6) on the growth of aquatic algae. The studies are as mentioned below: 

In the first predicted study for the target chemical Sodium 6-amino-5-[[4-chloro-2-(trifluoromethyl) phenyl]azo]-4-hydroxynaphthalene-2-sulphonate (57741-47-6) from QSAR toolbox 2017, study was carried out. Based on the prediction done using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the seven closest read across substances, toxicity on Desmodesmus subspicatus (previous name: Scenedesmus subspicatus) predicted for Sodium 6-amino-5-[[4-chloro-2-(trifluoromethyl)phenyl]azo] -4-hydroxy -naphthalene-2-sulphonate (57741-47-6). The EC50 value was estimated to be 144.5 mg/l when Sodium 6-amino-5-[[4-chloro-2-(trifluoromethyl)phenyl]azo]-4-hydroxynaphthalene -2-sulphonate exposed to Desmodesmus subspicatus for 72 hrs. Based on this value it can be concluded that the substance Sodium 6-amino-5-[[4-chloro-2-(trifluoromethyl) phenyl]azo]-4-hydroxynaphthalene-2-sulphonate (57741-47-6) is considered to be not toxic to aquatic environment and not classified as per the criteria mentioned in CLP regulation.   

 

First predicted study was supported by the other experimental study for the read across chemical (3734-67-6) from ABITEC lab report. Freshwater algal growth inhibition test was carried out on Desmodesmus subspicatus with the substance Disodium 5-acetylamino-4-hydroxy-3-(phenylazo)naphthalene-2,7- disulphonate according to OECD Guideline 201. The stock solution 100 mg/l was prepared by dissolving red powder in OECD growth medium. The solution was kept 30 min in ultrasonic bath. Test solutions of required concentration were prepared by mixing the stock solution of the test sample with OECD growth medium and inoculum culture. 5x10(3) cells /ml algal culture were use in the study for total exposure period of 72hrs. Test conducted in 50 ml glass vessel filled with 50 ml of sample volume and tested at the concentrations 0, 0, 20, 30, 45, 67, 100 mg/l. Effects on the growth rate of the organism were studied. The median effective concentration (ErC50) for the test substance Disodium 5-acetylamino-4-hydroxy-3-(phenylazo)naphthalene-2,7-disulphonate, in Desmodesmus subspicatus was determined to be 285.8 mg/L. This value indicates that the substance is likely to be non-hazardous to aquatic algae and cannot be classified as toxic as per the CLP criteria.

 

Similarly in the third weight of evidence study for the same read across chemical from UERL lab report 2016 study has been carried. Aim of this study was to determine the effect of test substance disodium 5-acetylamino-4-hydroxy-3-(phenylazo)naphthalene-2,7-disulphonate (3734 -67 -6) 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,12.5 mg/L,25 mg/L,50 mg/L,100 mg/L,200 mg/L. The test substance 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 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 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 test substance. The microscopic observations were also noted in each of the experimental flasks. All the cells appeared healthy, round and green throughout the test duration in the control and in the experimental flask also, no significant changes were observed. The EC50 calculated from equation through probit analysis on the basis of growth rate inhibition was observed to be 160.76 mg/L. Thus 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.

 

The fourth study from ABITEC lab consider for the read across chemical (915-67-3) as it is similar to the target chemical and also supports the nature of chemical. 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 stock solution (200 g/L) was prepared by dissolving brown powder in  OECD growth medium. Test solutions of required concentration were prepared by mixing the stock solution of the test sample with OECD growth medium and inoculum culture. 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 cannot be classified as toxic as per the CLP criteria.

 

 

Based on the predicted data for the target chemical and experimental studies for the read across chemical obtain from various sources (ABITEC and UERL lab report) toxicity on algae was studied and it was concluded that the chemical Sodium 6-amino-5-[[4-chloro-2-(trifluoromethyl)phenyl]azo]-4-hydroxynaphthalene-2-sulphonate (57741-47-6) was consider as nontoxic and can be consider to be not classified as toxic to aquatic invertebrates as per CLP classification criteria.