2-hydroxypyridine 1-oxide

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 QMRAF report has been attached.

Qualifier:

according to guideline

Guideline:

other: Estimated data

Version / remarks:

No data available

Deviations:

not specified

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 of test material : 2-Hydroxypyridine 1-oxide
- Molecular formula : C5H5NO2
- Molecular weight : 111.1 g/mol
- Smiles notation : n1(c(O)cccc1)=O
- InChl : 1S/C5H5NO2/c7-5-3-1-2-4-6(5)8/h1-4,7H
- Substance type: Organic
- Physical state: Solid

Analytical monitoring:

not specified

Details on sampling:

No data available

Vehicle:

not specified

Details on test solutions:

No data available

Test organisms (species):

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

Details on test organisms:

No data available

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Remarks on exposure duration:

No data available

Post exposure observation period:

No data available

Hardness:

No data available

Test temperature:

23 +/- 1 degrees Celsius

pH:

8.0 - 8.1

Dissolved oxygen:

No data available

Salinity:

No data available

Conductivity:

No data available

Nominal and measured concentrations:

No data available

Details on test conditions:

No data available

Reference substance (positive control):

not specified

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

158.015 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: Non toxic to algae

Details on results:

No data available

Results with reference substance (positive control):

No data available

Reported statistics and error estimates:

No data available

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 ( not "i") )  )  and ("j" and ( not "k") )  )  and ("l" and ( not "m") )  )  and "n" )  and ("o" and ( not "p") )  )  and "q" )  and ("r" and ( not "s") )  )  and ("t" and ( not "u") )  )  and "v" )  and "w" )  and "x" )  and ("y" and ( not "z") )  )  and ("aa" and ( not "ab") )  )  and ("ac" and ( not "ad") )  )  and ("ae" and "af" )  )

Domain logical expression index: "a"

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

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as Aryl OR Heterocyclic Phenol OR N-Oxide OR Pyridine by Organic Functional groups ONLY

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as Heterocyclic Phenol OR N-Oxide OR Overlapping groups by Organic Functional groups (nested) ONLY

Domain logical expression index: "d"

Referential boundary: The target chemical should be classified as Alcohol, olefinic attach [-OH] OR Aromatic Carbon [C] OR Aromatic Nitrogen OR Hydroxy, aromatic attach [-OH] OR Miscellaneous sulfide (=S) or oxide (=O) OR Nitrogen oxide, aromatic nitrogen [n=O] OR Nitrogen oxide, aromatic nitrogen [n=O] non fused  OR Olefinic carbon [=CH- or =C<] OR Oxygen, one aromatic attach [-O-] OR Pyridine, non fused rings  by Organic functional groups (US EPA) ONLY

Domain logical expression index: "e"

Referential boundary: The target chemical should be classified as Aromatic compound OR N-oxide OR Phenol by Organic functional groups, Norbert Haider (checkmol) 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, quinoid structures OR AN2 >>  Michael-type addition, quinoid structures >> Quinoneimines OR AN2 >> Nucleophilic addition to alpha, beta-unsaturated carbonyl compounds OR AN2 >> Nucleophilic addition to alpha, beta-unsaturated carbonyl compounds >> alpha, beta-Unsaturated Aldehydes OR AN2 >> Schiff base formation OR AN2 >> Schiff base formation >> alpha, beta-Unsaturated Aldehydes OR Michael addition OR Michael addition >> Quinone type compounds OR Michael addition >> Quinone type compounds >> Quinone methides OR Non-covalent interaction OR Non-covalent interaction >> DNA intercalation OR Non-covalent interaction >> DNA intercalation >> DNA Intercalators with Carboxamide Side Chain OR Non-covalent interaction >> DNA intercalation >> Fused-Ring Primary Aromatic Amines OR Radical OR Radical >> Radical mechanism by ROS formation OR Radical >> Radical mechanism by ROS formation >> Polynitroarenes OR Radical >> Radical mechanism via ROS formation (indirect) OR Radical >> Radical mechanism via ROS formation (indirect) >> Fused-Ring Primary Aromatic Amines 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 >> ROS formation after GSH depletion OR Radical >> ROS formation after GSH depletion (indirect) OR Radical >> ROS formation after GSH depletion (indirect) >> Quinoneimines OR Radical >> ROS formation after GSH depletion >> Quinone methides OR SN1 OR SN1 >> Alkylation after metabolically formed carbenium ion species OR SN1 >> Alkylation after metabolically formed carbenium ion species >> Polycyclic Aromatic Hydrocarbon Derivatives OR SN1 >> Nucleophilic attack after metabolic nitrenium ion formation OR SN1 >> Nucleophilic attack after metabolic nitrenium ion formation >> Fused-Ring Primary Aromatic Amines 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 SN1 >> Nucleophilic attack after reduction and nitrenium ion formation >> Polynitroarenes OR SN2 OR SN2 >> Alkylation, direct acting epoxides and related after P450-mediated metabolic activation OR SN2 >> Alkylation, direct acting epoxides and related after P450-mediated metabolic activation >> Polycyclic Aromatic Hydrocarbon Derivatives OR SN2 >> Direct acting epoxides formed after metabolic activation OR SN2 >> Direct acting epoxides formed after metabolic activation >> Quinoline Derivatives OR SN2 >> SN2 at an activated carbon atom OR SN2 >> SN2 at an activated carbon atom >> Quinoline Derivatives by DNA binding by OASIS v.1.3

Domain logical expression index: "h"

Referential boundary: The target chemical should be classified as No alert found by DNA binding by OECD

Domain logical expression index: "i"

Referential boundary: The target chemical should be classified as Acylation OR Acylation >> P450 Mediated Activation to Isocyanates or Isothiocyanates OR Acylation >> P450 Mediated Activation to Isocyanates or Isothiocyanates >> Benzylamines-Acylation OR Michael addition OR Michael addition >> P450 Mediated Activation to Quinones and Quinone-type Chemicals OR Michael addition >> P450 Mediated Activation to Quinones and Quinone-type Chemicals >> Alkyl phenols OR Michael addition >> P450 Mediated Activation to Quinones and Quinone-type Chemicals >> Arenes OR Michael addition >> P450 Mediated Activation to Quinones and Quinone-type Chemicals >> Hydroquinones OR Michael addition >> Polarised Alkenes-Michael addition OR Michael addition >> Polarised Alkenes-Michael addition >> Alpha, beta- unsaturated esters OR SN1 OR SN1 >> Carbenium Ion Formation OR SN1 >> Carbenium Ion Formation >> Allyl benzenes OR SN1 >> Iminium Ion Formation OR SN1 >> Iminium Ion Formation >> Aliphatic tertiary amines OR SN1 >> Nitrenium Ion formation OR SN1 >> Nitrenium Ion formation >> Aromatic nitro OR SN1 >> Nitrenium Ion formation >> Primary aromatic amine OR SN1 >> Nitrenium Ion formation >> Tertiary aromatic amine by DNA binding by OECD

Domain logical expression index: "j"

Referential boundary: The target chemical should be classified as No alert found by Protein binding by OASIS v1.3

Domain logical expression index: "k"

Referential boundary: The target chemical should be classified as Acylation OR Acylation >> Ester aminolysis OR Acylation >> Ester aminolysis >> Amides OR Michael Addition OR Michael Addition >> Polarised Alkenes OR Michael Addition >> Polarised Alkenes >> Polarised Alkene - alkenyl pyridines, pyrazines, pyrimidines or triazines  OR Nucleophilic addition OR Nucleophilic addition >> Addition to carbon-hetero double bonds OR Nucleophilic addition >> Addition to carbon-hetero double bonds >> Ketones OR Schiff base formation OR Schiff base formation >> Schiff base formation with carbonyl compounds OR Schiff base formation >> Schiff base formation with carbonyl compounds >> Aldehydes OR SNAr OR SNAr >> Nucleophilic aromatic substitution on activated aryl and heteroaryl compounds OR SNAr >> Nucleophilic aromatic substitution on activated aryl and heteroaryl compounds >> Activated aryl and heteroaryl compounds by Protein binding by OASIS v1.3

Domain logical expression index: "l"

Referential boundary: The target chemical should be classified as No alert found by Protein binding by OECD

Domain logical expression index: "m"

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 by Protein binding by OECD

Domain logical expression index: "n"

Referential boundary: The target chemical should be classified as High (Class III) by Toxic hazard classification by Cramer (original) ONLY

Domain logical expression index: "o"

Referential boundary: The target chemical should be classified as No Data by Ultimate biodeg

Domain logical expression index: "p"

Referential boundary: The target chemical should be classified as > 100 days by Ultimate biodeg

Domain logical expression index: "q"

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

Domain logical expression index: "r"

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

Domain logical expression index: "s"

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

Domain logical expression index: "t"

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

Domain logical expression index: "u"

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

Domain logical expression index: "v"

Referential boundary: The target chemical should be classified as Aryl AND Heterocyclic Phenol AND N-Oxide AND Pyridine by Organic Functional groups ONLY

Domain logical expression index: "w"

Referential boundary: The target chemical should be classified as Aryl AND Heterocyclic Phenol AND N-Oxide AND Pyridine by Organic Functional groups ONLY

Domain logical expression index: "x"

Referential boundary: The target chemical should be classified as Heterocyclic Phenol AND N-Oxide AND Overlapping groups by Organic Functional groups (nested) ONLY

Domain logical expression index: "y"

Referential boundary: The target chemical should be classified as (!Undefined)Group All Lipid Solubility < 0.01 g/kg AND (!Undefined)Group CN Lipid Solubility < 0.4 g/kg by Skin irritation/corrosion Exclusion rules by BfR

Domain logical expression index: "z"

Referential boundary: The target chemical should be classified as Group C Melting Point > 55 C OR Group CN Vapour Pressure < 0.001 Pa by Skin irritation/corrosion Exclusion rules by BfR

Domain logical expression index: "aa"

Referential boundary: The target chemical should be classified as Not known precedent reproductive and developmental toxic potential by DART scheme v.1.0

Domain logical expression index: "ab"

Referential boundary: The target chemical should be classified as Metals (1a) by DART scheme v.1.0

Domain logical expression index: "ac"

Referential boundary: The target chemical should be classified as Not known precedent reproductive and developmental toxic potential by DART scheme v.1.0

Domain logical expression index: "ad"

Referential boundary: The target chemical should be classified as Metal atoms were identified by DART scheme v.1.0

Domain logical expression index: "ae"

Parametric boundary:The target chemical should have a value of log Kow which is >= -4.34

Domain logical expression index: "af"

Parametric boundary:The target chemical should have a value of log Kow which is <= 1.94

Validity criteria fulfilled:

not specified

Conclusions:

EC50 value was estimated to be 158.0.54 mg/l for Species Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum) for 72 hrs duration when exposed to 2-Hydroxypyridine 1-oxide.

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 six closest read across substances, the toxicity on Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum) was predicted for Target substance 2-Hydroxypyridine 1-oxide (13161-30-3). EC50 value was estimated to be 158.0.54 mg/l for Species Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum) for 72 hrs duration when exposed to 2-Hydroxypyridine 1-oxide.

Based on this value it can be concluded that the substance 2-Hydroxypyridine 1-oxide is considered as 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 six closest read across substances, the toxicity on Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum) was predicted for Target substance 2-Hydroxypyridine 1-oxide (13161-30-3) EC50 value was estimated to be 158.0.54 mg/l for Species Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum) for 72 hrs duration when exposed to 2-Hydroxypyridine 1-oxide.

Based on this value it can be concluded that the substance 2-Hydroxypyridine 1-oxide is considered as not toxic to aquatic environment as per the criteria mentioned in CLP regulation. 

Key value for chemical safety assessment

EC50 for freshwater algae:

158.054 mg/L

Additional information

The toxicity of the chemical 2-Hydroxypyridine 1-oxide (13161-30-3) on the growth of aquatic algae was studied by considering and collecting the data from various databases for target chemical. Some RA (read across) chemicals was also studied. The results are summarised as below:

 

In the first weight of evidence study for 2-Hydroxypyridine 1-oxide (13161-30-3) based on the prediction done using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the six closest read across substances, the toxicity on Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum) was predicted for Target substance 2-Hydroxypyridine 1-oxide (13161-30-3). EC50 value was estimated to be 158.0.54 mg/l for Species Pseudokirchneriella subcapitata for 72 hrs duration when exposed to 2-Hydroxypyridine 1-oxide. Based on this value it can be concluded that the substance 2-Hydroxypyridine 1-oxide is considered as not toxic to aquatic environment as per the criteria mentioned in CLP regulation. 

 

In the second weight of evidence study for target chemical 2-Hydroxypyridine 1-oxide (13161-30-3) ECOSAR, 2017, Based on the prediction done using the EPI Suite ECOSAR version 1.11, the short term toxicity on green algae was predicted for test substance pyridin-2-ol 1-oxide (13161 -30 -3). On the basis of effects observed in a static freshwater system, the effect concentration EC50 value for the substance is estimated to be 5117 mg/l for green algae for 98 hrs duration. Based on this value, it can be concluded that the test chemical pyridin-2-ol 1-oxide can be considered as non-toxic to green algae at environmentally relevant concentrations and can be considered not-classified as toxic as per the CLP classification criteria.

 

Similarly in the third weight of evidence study for RA chemical (108-80-5) J-check and HSDB, 2017, Short term toxicity study of Isocyanuric acid (IUPAC name 1,3,5-Triazin-2,4,6-triol )on the growth of freshwater green algae was carried out for 72 hrs. The effective concentration (EC50) value of aquatic green algae in a 72 hr study on the basis of growth rate effect and AUG was 950 mg/l and 620 mg/l. But the NOEC on the basis of growth rate AUG and was 250 mg/l and 22 mg/l. Based on the growth rate and AUG of green algae by considering EC50, Isocyanuric acid (IUPAC name 1,3,5-Triazin-2,4,6-triol ) was nontoxic and cannot be classified as toxic to aquatic algae as per the CLP classification criteria.

 

Similarly in the fourth weight of evidence study for RA chemical (108-80-5) from IUCLID dataset Short term toxicity study of Isocyanuric acid (IUPAC name 1,3,5-Triazin-2,4,6-triol )on the growth of freshwater green algae Selenastrum capricornutums was carried out for 96 hrs. The effective concentration (EC50) value of aquatic green algae in a 96 hr. study on the basis of biomass was 712 mg/l, but the NOEC and LOEC on the basis of biomass was ≤ 100 mg/l and 320 mg/l. Based on the inhibition of biomass of green algae by considering EC50, cyanuric acid (IUPAC name 1,3,5-Triazin-2,4,6-triol ) was nontoxic and cannot be classified as toxic to aquatic algae as per the CLP classification criteria.

Based on this value it can be concluded that the substance 2-Hydroxypyridine 1-oxide is likely to be non toxic at environmentally relevant concentrations and can be considered as 'not classified' as per the criteria mentioned in CLP regulation.