7-acetamido-4-hydroxynaphthalene-2-sulphonic 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 the 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

GLP compliance:

not specified

Specific details on test material used for the study:

- Name of test material: 7-acetamido-4-hydroxynaphthalene-2-sulfonic acid
- Molecular formula: C12H11NO5S
- Molecular weight: 281.2869 g/mol
- Smiles notation: CC(=O)Nc1ccc2c(c1)cc(cc2O)S(=O)(=O)O
- InChl: 1S/C12H11NO5S/c1-7(14)13-9-2-3-11-8(4-9)5-10(6-12(11)15)19(16,17)18/h2-6,15H,1H3,(H,13,14)(H,16,17,18)
- Substance type: Organic

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

Hardness:

No data available

Test temperature:

22 °C

pH:

7.6 to 9.0

Nominal and measured concentrations:

Estimated

Reference substance (positive control):

not specified

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

193.45 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: Non 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" )  and "e" )  and "f" )  and "g" )  and ("h" and ( not "i") )  )  and ("j" and ( not "k") )  )  and ("l" and ( not "m") )  )  and ("n" and ( not "o") )  )  and ("p" and ( not "q") )  )  and ("r" and ( not "s") )  )  and ("t" and ( not "u") )  )  and ("v" and ( not "w") )  )  and "x" )  and "y" )  and ("z" and "aa" )  )

Domain logical expression index: "a"

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

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as Acylation AND Acylation >> Ester aminolysis AND Acylation >> Ester aminolysis >> Amides by Protein binding by OASIS v1.3

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as Acylation AND Acylation >> Direct Acylation Involving a Leaving group AND Acylation >> Direct Acylation Involving a Leaving group >> Acetates by Protein binding by OECD

Domain logical expression index: "d"

Referential boundary: The target chemical should be classified as Acid moiety AND Amides AND Phenol Amines AND Phenols by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "e"

Referential boundary: The target chemical should be classified as Discrete chemical by Substance Type ONLY

Domain logical expression index: "f"

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: "g"

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

Domain logical expression index: "h"

Referential boundary: The target chemical should be classified as Acid moiety AND Amides AND Phenol Amines AND Phenols by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "i"

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

Domain logical expression index: "j"

Referential boundary: The target chemical should be classified as Acid moiety AND Amides AND Phenol Amines AND Phenols by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "k"

Referential boundary: The target chemical should be classified as Halo Ketones (2 free H) by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "l"

Referential boundary: The target chemical should be classified as Acid moiety AND Amides AND Phenol Amines AND Phenols by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "m"

Referential boundary: The target chemical should be classified as Phenols, Poly OR Pyrazoles/Pyrroles OR Substituted Ureas by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "n"

Referential boundary: The target chemical should be classified as Acid moiety AND Amides AND Phenol Amines AND Phenols by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "o"

Referential boundary: The target chemical should be classified as Vinyl/Allyl Alcohols OR Vinyl/Allyl Esters OR Vinyl/Allyl Ethers OR Vinyl/Allyl Ketones by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "p"

Referential boundary: The target chemical should be classified as Acid moiety AND Amides AND Phenol Amines AND Phenols by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "q"

Referential boundary: The target chemical should be classified as Surfactants-Anionic by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "r"

Referential boundary: The target chemical should be classified as Acid moiety AND Amides AND Phenol Amines AND Phenols by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "s"

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

Domain logical expression index: "t"

Referential boundary: The target chemical should be classified as Acid moiety AND Amides AND Phenol Amines AND Phenols by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "u"

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

Domain logical expression index: "v"

Referential boundary: The target chemical should be classified as Acid moiety AND Amides AND Phenol Amines AND Phenols by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "w"

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

Domain logical expression index: "x"

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

Domain logical expression index: "y"

Similarity boundary:Target: CC(=O)Nc1ccc2c(c1)cc(S(O)(=O)=O)cc2O
Threshold=10%,
Dice(Atom centered fragments)
Atom type; Count H attached; Hybridization

Domain logical expression index: "z"

Parametric boundary:The target chemical should have a value of log Kow which is >= -2.37

Domain logical expression index: "aa"

Parametric boundary:The target chemical should have a value of log Kow which is <= 2.76

Validity criteria fulfilled:

not specified

Conclusions:

The effective concentration (EC50) for the test compound 7-acetamido-4-hydroxy-naphthalene-2-sulfonic to be 193.449 mg/l on the basis of effects on growth rate.

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 five closest read across substances,72 hrs. aquatic toxicity estimation was performed to assess toxic effects of the test compound 7-acetamido-4-hydroxy-naphthalene-2-sulfonic (CAS no.6334-97-0) and the result were predicted. The study was based on the effects of the test compound on Desmodesmus subspicatus in a static fresh water system. The predicted data suggests the effective concentration (EC50) for the test compound 7-acetamido-4-hydroxy-naphthalene-2-sulfonic to be 193.449 mg/l on the basis of effects on growth rate. Based on this value it can be concluded that the substance 7-acetamido-4-hydroxy-naphthalene-2-sulfonic is considered to be not toxic to aquatic environment 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 five closest read across substances,72 hrs. aquatic toxicity estimation was performed to assess toxic effects of the test compound 7-acetamido-4-hydroxy-naphthalene-2-sulfonic acid (CAS no.6334-97-0) and the result were predicted. The study was based on the effects of the test compound on Desmodesmus subspicatus in a static fresh water system. The predicted data suggests the effective concentration (EC50) for the test compound 7-acetamido-4-hydroxy-naphthalene-2-sulfonic acid to be 193.449 mg/l on the basis of effects on growth rate. Based on this value it can be concluded that the substance 7-acetamido-4 -hydroxy- naphthalene-2-sulfonic acid is considered to be not toxic to aquatic environment as per the criteria mentioned in CLP regulation. 

Key value for chemical safety assessment

EC50 for freshwater algae:

193.449 mg/L

Additional information

Short term toxicity to aquatic algae:

Various predicted data for the target compound 7-acetamido-4-hydroxynaphthalene-2-sulfonic acid (6334-97-0) 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), Based on the prediction done using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the five closest read across substances,72 hrs. aquatic toxicity estimation was performed to assess toxic effects of the test compound 7-acetamido-4-hydroxy- naphthalene-2-sulfonic acid(CAS no.6334-97-0) and the result were predicted. The study was based on the effects of the test compound on Desmodesmus subspicatus in a static fresh water system. The predicted data suggests the effective concentration (EC50) for the test compound 7-acetamido-4-hydroxy-naphthalene-2-sulfonic acid to be 193.449 mg/l on the basis of effects on growth rate. Based on this value it can be concluded that the substance 7-acetamido-4-hydroxy-naphthalene-2-sulfonic acid is considered to be not toxic to aquatic environment as per the criteria mentioned in CLP regulation. 

 

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-hydroxy - naphthalene-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 in a supporting weight of evidence study from (Water Research Pergamon Press 1968) for RA chemical (98-37-3) toxicity experiment was conducted, short term toxicity to Chlorella pyrenoidosa (green algae) study was carried out for 72 hrs. Emerson strain of bacteria free, experimentally reproducible cultures of Chlorella pyrenoidosa was used as a test organism. The procedure involve the use of test tubes in both the screening and final tests. These test tubes contained 15 ml of inorganic culture medium, a predetermined amount of test chemical and 5 ml of algal culture. The tubes were incubated for 72 hrs and chlorophyll content of the algal suspensions was measured every 24 hrs. For chlorophyll measurement, the chlorophyll pigment was extracted with hot methanol in two separate extractions. An algal suspension, 2.5 ml, was removed from the test tube, centrifuged, washed with distilled water, and recentrifuged in preparation of chlorophyll analysis. After discarding the supernatant, the deposited cell material was coagulated by placing the cells in a boiling water bath for about 40 sec. About 2.5 ml of methanol were used in each extraction. Finally, the chlorophyll solution was diluted to a total volume of 10 ml with an acetone-water mixture (80 per cent by volume). A Beckman Spectrophotometer, Model DB, was used to measure the chlorophyll content according to MACKIN~v (1941) and ARNON (1949). For this a wavelength of 652 m/z was used because different proportions of chlorophyll a and b least affect the results at this wavelength. Control tubes containing no test chemical was also used in the experiment. Knop's solution, including the Hutner-EDTA microelement addition, was used as the culture medium. pH of culture medium was adjusted to 7.0 using KOH before use. The test organism was maintained under steady-state conditions, provided a chlorophyll content of 38 mg/l. Environmental control was rigidly maintained. The temp. of water bath was 25 ± 1°C. The test apparatus consisted of a constant-temperature water bath, a light source containing four 200W fluorescent lamps with attached aluminum reflectors, a gas manifold to supply an air-CO2 mixture to each test tube, and a rack to hold the test tubes. A stream of 5 % CO2 in air gas mixture was supplied to culture medium in order to provide the inorganic carbon source and also to keep the algal ceils in suspension. Based on destruction of chlorophyll of test organism by test chemical Amino-1-phenol-4-sulfonic acid, the LOEC value was determine to be 1500 mg/l and as no toxic effect at 1000 mg/l was observed, the NOEC value was determine to be 1000 mg/l. Thus, based on this value, it can be concluded that the substance can be considered as non-toxic to aquatic organisms and thus cannot be classified as hazardous as per the CLP criteria.

 

Similarly in a supporting weight of evidence study from j-check for read across chemical 2'-Methylacetoacetanilide (93-68-5), Short term toxicity of 2'-Methylaceto- acetanilide was studied on the growth of freshwater green algae. Test was performed by static system for 72hrs. After the exposure of chemical with the green algae, effect concentration was observed at which 50% growth inhibited due to the chemical. On the basis of growth rate the EC50 was 750 mg/l and NOEC was 170 mg/l, but on the basis of area under the growth curve the EC50 and NOEC was 380 mg/l and 95 mg/l. Based on the EC50 value (750 and 380 mg/l) 2'-Methylacetoacetanilide was concluded to be nontoxic and can be consider to be not classified as toxic as per the CLP classification criteria.

 

Similarly in fifth weight of evidence study for the same read across chemical 98-37-3 (from reviewed article, 1967) Short term toxicity to Chlorella pyrenoidosa (green algae) study was carried out for 72 hrs. Emerson strain of bacteria free, experimentally reproducible cultures ofChlorella pyrenoidosa was used as a test organism. An Emerson strain of bacteria-free, experimentally reproducible cultures ofChlorella pyrenoidosa was obtained from Dr.Jack E. Myers, Professor of Zoology and Botany and Director, Laboratory of Algal Physiology,The University of Texas. Five conc. levels of test chemical were used for the tests (100, 500, 1000, 1500 and 2000 mg/l, respectively). A test tubes was used in the screening and final tests. These test tubes contained 15 ml of inorganic culture medium, a predetermined amount of test chemical and 5 ml of algal culture. The tubes were incubated for 72 hrs andchlorophyll content of the algal suspensions was measured every 24 hrs.Control tubes containing no test chemical in the culture medium was also used in the experiment.Environmental control was rigidly maintained. The temp of water bath was 25 ± 1°C.The special toxicity test device consisted of an aquarium complete with a light source,a gas manifold and an apparatus for holding the test tubes. In this test device, algal cultures were kept under a rigid environmental control.A stream of 5 % CO2 in air gas mixture was supplied to culture medium in order to provide the inorganic carbon source and also to keep the algal cells in suspension. Screening tests were performed to establish the threshold toxic concentration as well as completely algicidic one. Knop's solution, including the Hutner-EDTA microelement addition, was used as the culture medium. pH of culture medium was adjusted to 7.0 using KOH before use. Kimble Product of plain culture tubes, Series 45060, was used as the test tube. These test tubes have the size of 19 x 150 mm with a volume of 25 mI. The initial algal cell density was1.0 gm/l dry weight or equivalent to 3.8 cm/ml packed cell volume andchlorophyll content was 38 mg/l.The chlorophyll pigment was extracted with hot methanol from a 2.5mlalgal suspension which was pipetted out of the test tube. The algal cells were centrifuged out of the culture medium, washed with distilled water and then centrifuged again. The supernatant was discarded and the remaining packed cell material was coagulatedina boiling water bath for a period of about 30 to 45 seconds depending on the amount of cells.Thereafter,the chlorophyll was extracted twice by using hot methanol. The extracted chlorophyll solution was then dissolved in 80 percent by volume acetone-water mixture to make a final total volume of 10 ml. The chlorophyll content was then analyzed under the spectrophotometer.Content of all extracted chlorophylls which were dissolved in 10ml of 80 percent acetone-water mixture could be determined by measuring the optical density (O.D.) at a wavelength of 652 nm.This wavelength was optimum because various proportions of chlorophylls a and b would least affect the result. A BeckmanSpectrophotometer,Model DB, was used for all chlorophyll analysis. This spectrophotometer is a double beam instrument for making transmittance and absorbance measurements in the 205 to 770 nm wavelength range.Based on the decrease in chlorophyll content of test organism by test chemical Amino-1-phenol-4-sulfonic acid, the LOEC value was determine to be 2000 mg/l and as no toxic effect at 1000 mg/l was observed, the NOEC value was determine to be 1000 mg/l.

 

On the basis of above results for target chemical 7-acetamido-4-hydroxynaphthalene-2-sulfonic acid (6334-97-0) (from OECD QSAR toolbox version 3.4, 2017) and for its read across substance from ABITEC report, Water Research Pergamon Press 1968, peer reviewed journal and authoritative database, it can be concluded that the test substance 7-acetamido -4-hydroxynaphthalene-2-sulfonic acid is not toxic and can be consider to be not classified as toxic as per the CLP classification criteria.