Disodium 8-hydroxynaphthalene-1,6-disulphonate

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 3.4.

GLP compliance:

not specified

Specific details on test material used for the study:

- Chemical name: disodium 8-hydroxynaphthalene-1,6-disulfonate
- Molecular formula: C10-H8-O7-S2.2Na
- Molecular weight: 348.2624 g/mole
- Smiles: c1cc2cc(cc(c2c(c1)S(=O)(=O)[O-])O)S(=O)(=O)[O-].[Na+].[Na+]
- Inchl: 1S/C10H8O7S2.2Na/c11-8-5-7(18(12,13)14)4-6-2-1-3-9(10(6)8)19(15,16)17;;/h1-5,11H,(H,12,13,14)(H,15,16,17);;/q;2*+1/p-2
- Substance type: Organic
- Physical state:

Analytical monitoring:

not specified

Vehicle:

not specified

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Details on test organisms:

- Common name: Water flea

Test type:

static

Water media type:

freshwater

Total exposure duration:

72 h

Hardness:

24 mg/L as CaCO3

Test temperature:

24 °C

pH:

7.3 - 8.3

Nominal and measured concentrations:

Estimated data

Reference substance (positive control):

not specified

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

234.471 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: Other details not known

Details on results:

The EC50 was 234.47 mg/l on the basis of growth rate inhibition.

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" )  and ("e" and ( not "f") )  )  and ("g" and ( not "h") )  )  and ("i" and ( not "j") )  )  and ("k" and ( not "l") )  )  and ("m" and ( not "n") )  )  and ("o" and ( not "p") )  )  and "q" )  and ("r" and ( not "s") )  )  and ("t" and ( not "u") )  )  and ("v" and "w" )  )

Domain logical expression index: "a"

Referential boundary: The target chemical should be classified as Naphthalene sulfonic acids, condensates by OECD HPV Chemical Categories

Domain logical expression index: "b"

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

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as AN2 AND AN2 >> Michael-type addition to quinoid structures  AND AN2 >> Michael-type addition to quinoid structures  >> Substituted Phenols by Protein binding by OASIS v1.4

Domain logical expression index: "d"

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

Domain logical expression index: "e"

Referential boundary: The target chemical should be classified as No alert found by DNA binding by OASIS v.1.4

Domain logical expression index: "f"

Referential boundary: The target chemical should be classified as AN2 OR AN2 >>  Michael-type addition, quinoid structures OR AN2 >>  Michael-type addition, quinoid structures >> Quinones and Trihydroxybenzenes 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 and Aminoalkylamine Side Chain OR Non-covalent interaction >> DNA intercalation >> Quinones and Trihydroxybenzenes OR Radical OR Radical >> Generation of ROS by glutathione depletion (indirect) OR Radical >> Generation of ROS by glutathione depletion (indirect) >> Haloalkanes Containing Heteroatom OR Radical >> Radical mechanism via ROS formation (indirect) OR Radical >> Radical mechanism via ROS formation (indirect) >> Nitroaniline Derivatives OR Radical >> Radical mechanism via ROS formation (indirect) >> Nitrophenols, Nitrophenyl Ethers and Nitrobenzoic Acids OR Radical >> Radical mechanism via ROS formation (indirect) >> Quinones and Trihydroxybenzenes OR SN1 OR SN1 >> Nucleophilic attack after carbenium ion formation OR SN1 >> Nucleophilic attack after carbenium ion formation >> Specific Acetate Esters OR SN1 >> Nucleophilic attack after reduction and nitrenium ion formation OR SN1 >> Nucleophilic attack after reduction and nitrenium ion formation >> Nitroaniline Derivatives OR SN1 >> Nucleophilic attack after reduction and nitrenium ion formation >> Nitrophenols, Nitrophenyl Ethers and Nitrobenzoic Acids OR SN2 OR SN2 >> Acylation OR SN2 >> Acylation >> Specific Acetate Esters OR SN2 >> Alkylation, direct acting epoxides and related OR SN2 >> Alkylation, direct acting epoxides and related >> Epoxides and Aziridines OR SN2 >> Alkylation, nucleophilic substitution at sp3-carbon atom OR SN2 >> Alkylation, nucleophilic substitution at sp3-carbon atom >> Haloalkanes Containing Heteroatom OR SN2 >> Nucleophilic substitution at sp3 Carbon atom OR SN2 >> Nucleophilic substitution at sp3 Carbon atom >> Haloalkanes Containing Heteroatom OR SN2 >> Nucleophilic substitution at sp3 Carbon atom >> Specific Acetate Esters by DNA binding by OASIS v.1.4

Domain logical expression index: "g"

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

Domain logical expression index: "h"

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

Domain logical expression index: "i"

Referential boundary: The target chemical should be classified as AN2 AND AN2 >> Michael-type addition to quinoid structures  AND AN2 >> Michael-type addition to quinoid structures  >> Substituted Phenols by Protein binding by OASIS v1.4

Domain logical expression index: "j"

Referential boundary: The target chemical should be classified as Acylation OR Acylation >> Acylation involving an activated (glucuronidated) ester group OR Acylation >> Acylation involving an activated (glucuronidated) ester group >> Arenecarboxylic Acid Esters by Protein binding by OASIS v1.4

Domain logical expression index: "k"

Referential boundary: The target chemical should be classified as AN2 AND AN2 >> Michael-type addition to quinoid structures  AND AN2 >> Michael-type addition to quinoid structures  >> Substituted Phenols by Protein binding by OASIS v1.4

Domain logical expression index: "l"

Referential boundary: The target chemical should be classified as No alert found by Protein binding by OASIS v1.4

Domain logical expression index: "m"

Referential boundary: The target chemical should be classified as AN2 AND AN2 >> Michael-type addition to quinoid structures  AND AN2 >> Michael-type addition to quinoid structures  >> Substituted Phenols by Protein binding by OASIS v1.4

Domain logical expression index: "n"

Referential boundary: The target chemical should be classified as Schiff base formation >> Schiff base formation with carbonyl compounds >> Aromatic carbonyl compounds by Protein binding by OASIS v1.4

Domain logical expression index: "o"

Referential boundary: The target chemical should be classified as Group 1 - Alkali Earth Li,Na,K,Rb,Cs,Fr AND Group 14 - Carbon C AND Group 16 - Oxygen O AND Group 16 - Sulfur S by Chemical elements

Domain logical expression index: "p"

Referential boundary: The target chemical should be classified as Group 15 - Nitrogen N OR Group 17 - Halogens Cl OR Group 17 - Halogens F,Cl,Br,I,At by Chemical elements

Domain logical expression index: "q"

Similarity boundary:Target: Oc1cc(S(=O)(=O)O{-}.[Na]{+})cc2cccc(S(=O)(=O)O{-}.[Na]{+})c12
Threshold=30%,
Dice(Atom centered fragments)
Atom type; Count H attached; Hybridization

Domain logical expression index: "r"

Referential boundary: The target chemical should be classified as Benzene/ Naphthalene sulfonic acids (Less susceptible) Rank C by Repeated dose (HESS)

Domain logical expression index: "s"

Referential boundary: The target chemical should be classified as Phenols (Mucous membrane irritation) Rank C by Repeated dose (HESS)

Domain logical expression index: "t"

Referential boundary: The target chemical should be classified as Anion AND Aromatic compound AND Cation AND Hydroxy compound AND Phenol AND Sulfonic acid derivative by Organic functional groups, Norbert Haider (checkmol)

Domain logical expression index: "u"

Referential boundary: The target chemical should be classified as Enolether by Organic functional groups, Norbert Haider (checkmol)

Domain logical expression index: "v"

Parametric boundary:The target chemical should have a value of Molecular weight which is >= 124 Da

Domain logical expression index: "w"

Parametric boundary:The target chemical should have a value of Molecular weight which is <= 549 Da

Validity criteria fulfilled:

not specified

Conclusions:

Based on the growth rate inhibition of algae, the EC50 value was estimated to be 234.47 mg/l when disodium 8-hydroxynaphthalene-1,6-disulfonate exposed to Pseudokirchneriella subcapitata for 72hrs

Executive summary:

Based on the prediction done using the OECD QSAR toolbox version 3.4 with log kow as the primary descriptor and considering the seven closest read across substances, toxicity on Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum) was predicted for disodium 8-hydroxynaphthalene-1,6-disulfonate (83732-80-3). Based on the growth rate inhibition of algae,the EC50 value was estimated to be 234.47 mg/l when disodium 8-hydroxynaphthalene-1,6-disulfonate exposed to Pseudokirchneriella subcapitata for 72hrs. Based on this value it can be concluded that the substance disodium 8-hydroxynaphthalene-1,6-disulfonate 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 3.4 with log kow as the primary descriptor and considering the seven closest read across substances, toxicity on Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum) was predicted for disodium 8-hydroxy - naphthalene-1,6-disulfonate (83732-80-3). Based on the growth rate inhibition of algae,the EC50 value was estimated to be 234.47 mg/l when disodium 8-hydroxynaphthalene -1,6-disulfonate exposed to Pseudokirchneriella subcapitata for 72hrs. Based on this value it can be concluded that the substance disodium 8-hydroxynaphthalene-1,6-disulfonate 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:

234.47 mg/L

Additional information

Various predicted data for the target compound disodium 8-hydroxynaphthalene-1,6-disulfonate (83732-80-3) and experimental data for supporting weight of evidence studies for its closest read across substance with log Kow as the primary descriptor and structural, functional similarities were reviewed for the toxicity on the aquatic algae and cyanobacteria 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 3.4 with log kow as the primary descriptor and considering the seven closest read across substances, toxicity on Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum) was predicted for disodium 8-hydroxy - naphthalene-1,6-disulfonate (83732-80-3). Based on the growth rate inhibition of algae,the EC50 value was estimated to be 234.47 mg/l when disodium 8-hydroxynaphthalene -1,6-disulfonate exposed to Pseudokirchneriella subcapitata for 72hrs. Based on this value it can be concluded that the substance disodium 8-hydroxynaphthalene-1,6-disulfonate is considered to be not toxic to aquatic environment as per the criteria mentioned in CLP regulation.   

 

Similarly in a second supporting weight of evidence study from ABITEC report 2016 for read across chemical 5-amino-4-hydroxy-3-(phenylazo)naphthalene-2,7-disulphonate (3567-66-6), Freshwater algal growth inhibition test was carried out on Desmodesmus subspicatus with the substance disodium 5-amino-4-hydroxy-3-(phenylazo)naphthalene -2,7-disulphonate according to OECD Guideline 201. The test substance was dissolved in OECD growth medium and tested at the concentrations 0, 0, 12.5, 25, 100, 200 mg/L. Effects on the growth rate of the organism were studied. The median effective concentration (ErC50) for the test substance, disodium 5-amino-4-hydroxy- 3-(phenylazo)naphthalene-2,7-disulphonate, in Desmodesmus subspicatus was determined to be 330.2 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 disodium 5-amino-4-hydroxy-3-(phenylazo) naphthalene- 2,7-disulphonate does not exhibit toxicity to aquatic algae (Desmodesmus subspicatus) and not classified as toxic as per the CLP classification criteria. 

 

Further first predicted study was supported by the another weight of evidence studies for the structurally similar read across chemical Disodium 3-[(2,4-dimethyl- 5-sulpho- natophenyl) azo]-4-hydroxy naphthalene-1-sulphonate (4548-53-2) from ABITEC report. Freshwater algal growth inhibition test was carried out on Desmodesmus subspicatus with the substance Disodium 3-[(2,4-dimethyl -5-sulphonatophenyl) azo]-4-hydroxynaphthalene -1-sulphonate according to OECD Guideline 201. The test substance was dissolved in OECD growth medium and tested at the concentrations 0, 0, 12.5, 25, 50, 100 and 200 mg/L. Effects on the growth rate of the organism were studied. The median effective concentration (ErC50) for the test substance, Disodium 3-[(2,4-dimethyl-5-sulphonatophenyl)azo]- 4-hydro xynaphthalene-1-sulphonate, in Desmodesmus subspicatus was determined to be 276.1 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 Disodium 3-[(2,4-dimethyl-5-sulphonatophenyl) azo]-4-hydroxynaphthalene-1-sulphonate does not exhibit toxicity to aquatic algae (Desmodesmus subspicatus).

 

Similarly by considering data for 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-hydroxynaphthalene-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 for the same read across chemical, toxicity study was conducted on algae and reported from UERL lab, 2016, The effect of test item 4-amino-5-hydroxynaphthalene- 1,7-disulphonic acid, CAS No. 130-23-4 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 6.25mg/l, 12.5mg/l, 25mg/l, 50mg/l, 100mg/l and 200mg/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 >200mg/l. Thus, based on the EC50 value, test substance 4-amino-5-hydroxynaphthalene-1,7-disulphonic acid can be classified as not hazardous and nontoxic as per the criteria of CLP regulation.

 

Thus based on the predicted data from QSAR toolbox version 3.4 for target chemical disodium 8-hydroxynaphthalene-1,6-disulfonate (83732-80-3) and also considering experimental K1 data for structurally and functionally similar read across chemical from ABITEC lab and UERL lab, it can be concluded that the chemical disodium 8-hydroxynaphthalene-1,6-disulfonate (83732-80-3) was nontoxic to the aquatic algae and cyanobacteria and can be consider to be not classified as toxic as per the CLP classification criteria.