2-hydroxypyridine 1-oxide

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: screening tests

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:

The supporting QMRF report has been attached

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))

Principles of method if other than guideline:

The data is predicted using the OECD QSAR toolbox version 3.3 with logKow as the primary descriptor.

GLP compliance:

not specified

Specific details on test material used for the study:

- Name of test material (IUPAC name): 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

Oxygen conditions:

aerobic

Inoculum or test system:

other: Microorganisms

Duration of test (contact time):

28 d

Based on:

not specified

Parameter followed for biodegradation estimation:

other: BOD

Key result

Parameter:

other: BOD

Value:

17.4

Sampling time:

28 d

Remarks on result:

other: Other details not known

Details on results:

Test substance undergoes 17.4% degradation by BOD in 28 days.

The prediction was based on dataset comprised from the following descriptors: BOD
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 "g" )  and ("h" and ( not "i") )  )  and ("j" and ( not "k") )  )  and "l" )  and ("m" and ( not "n") )  )  and "o" )  and "p" )  and "q" )  and "r" )  and ("s" and "t" )  )

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 Does NOT Biodegrade Fast by Biodeg probability (Biowin 5) ONLY

Domain logical expression index: "g"

Referential boundary: The target chemical should be classified as Not calculated by Biodeg BioHC half-life (Biowin) ONLY

Domain logical expression index: "h"

Referential boundary: The target chemical should be classified as Aromatic alcohol  [-OH] AND Aromatic-H by Biodegradation fragments (BioWIN MITI)

Domain logical expression index: "i"

Referential boundary: The target chemical should be classified as Aromatic-CH2 by Biodegradation fragments (BioWIN MITI)

Domain logical expression index: "j"

Referential boundary: The target chemical should be classified as Aromatic alcohol  [-OH] AND Aromatic-H by Biodegradation fragments (BioWIN MITI)

Domain logical expression index: "k"

Referential boundary: The target chemical should be classified as Pyridine ring by Biodegradation fragments (BioWIN MITI)

Domain logical expression index: "l"

Referential boundary: The target chemical should be classified as Very fast by Bioaccumulation - metabolism half-lives ONLY

Domain logical expression index: "m"

Referential boundary: The target chemical should be classified as Stable form by Tautomers unstable

Domain logical expression index: "n"

Referential boundary: The target chemical should be classified as Hydroxyazo form - 1,5-H shift OR Hydroxyazo form (fused rings) - 1,5-H shift OR Lactim form by Tautomers unstable

Domain logical expression index: "o"

Referential boundary: The target chemical should be classified as Aromatic compound AND N-oxide AND Phenol by Organic functional groups, Norbert Haider (checkmol) ONLY

Domain logical expression index: "p"

Referential boundary: The target chemical should be classified as Aromatic compound AND N-oxide AND Phenol by Organic functional groups, Norbert Haider (checkmol) ONLY

Domain logical expression index: "q"

Referential boundary: The target chemical should be classified as Aromatic compound AND N-oxide AND Phenol by Organic functional groups, Norbert Haider (checkmol) ONLY

Domain logical expression index: "r"

Referential boundary: The target chemical should be classified as Aromatic compound AND N-oxide AND Phenol by Organic functional groups, Norbert Haider (checkmol) ONLY

Domain logical expression index: "s"

Parametric boundary:The target chemical should have a value of Molecular weight which is >= 109 Da

Domain logical expression index: "t"

Parametric boundary:The target chemical should have a value of Molecular weight which is <= 152 Da

Validity criteria fulfilled:

not specified

Interpretation of results:

not readily biodegradable

Conclusions:

The test chemical 2-Hydroxypyridine 1-oxide was estimated to be not readily biodegradable in water.

Executive summary:

Biodegradability of 2-Hydroxypyridine 1-oxide (CAS no. 13161 -30 -3) is predicted using OECD QSAR toolbox version 3.3 with logKow as the primary descriptor. Test substance undergoes 17.4% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical 2-Hydroxypyridine 1-oxide was estimated to be not readily biodegradable in water.

Description of key information

Biodegradability of 2-Hydroxypyridine 1-oxide (CAS no. 13161 -30 -3) is predicted using OECD QSAR toolbox version 3.3 (2017) with logKow as the primary descriptor. Test substance undergoes 17.4% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical 2-Hydroxypyridine 1-oxide was estimated to be not readily biodegradable in water.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Additional information

Various predicted data for the target compound 2-Hydroxypyridine 1-oxide(CAS No. 13161-30-3) and supporting weight of evidence studies for its closest read across substance with logKow as the primary descriptor were reviewed for the biodegradation end point which are summarized as below:

 

In a prediction done by SSS (2017) using OECD QSAR toolbox version 3.3 with logKow as the primary descriptor, percentage biodegradability of test chemical 2-Hydroxypyridine 1-oxide(CAS No. 13161-30-3) was estimated.Test substance undergoes 17.4% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical 2-Hydroxypyridine 1-oxide was estimated to be not readily biodegradable in water.

 

In a prediction done by SSS (2017) using OECD QSAR toolbox version 3.3 with logKow as the primary descriptor, percentage biodegradability of test chemical 2-Hydroxypyridine 1-oxide(CAS No. 13161-30-3) was estimated.The biodegradability of the substance was calculated using seven different models such as Linear Model, Non-Linear Model, Ultimate Biodegradation Timeframe, Primary Biodegradation Timeframe, MITI Linear Model, MITI Non-Linear Model and Anaerobic Model (called as Biowin 1-7, respectively) of the BIOWIN v4.10 software. The results indicate that chemical 2-Hydroxypyridine 1-oxide is expected to be not readily biodegradable.

 

In a supporting weight of evidence study from peer reviewed journal (H. Heukelekian and M. C. Rand, 1955) for the read across chemical 1,3,5-Triazine-2,4,6-triamine (CAS no. 108-78-1), biodegradation experiment was conducted for 5 days for evaluating the percentage biodegradability of read across substance 1,3,5-Triazine-2,4,6-triamine using standard dilution method under aerobic conditions at a temperature of 20°C. Sewage was used as a test inoculum. The 5 day BOD value of chemical 1,3,5-Triazine-2,4,6-triamine was determined to be 0.006 g/g. Thus, based on this value, 1,3,5-Triazine-2,4,6-triamine is considered to be not readily biodegradable in nature.

 

Another biodegradation study from authoritative database (J-CHECK, 2017 and EnviChem, 2014) was conducted for 14 days for evaluating the percentage biodegradability of read across substance 1,3,5-Triazine-2,4,6-triamine (CAS no. 108-78-1). The study was performed according to OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I)). Concentration of inoculum i.e, sludge used was 30 mg/l and initial test substance conc. used in the study was 100 mg/l, respectively. The percentage degradation of substance 1,3,5-Triazine-2,4,6-triamine was determined to be 0 and < 0% by BOD, O2 consumption, TOC removal, test mat. analysis, UV-Vis and HPLC parameter in 14 days. Thus, based on percentage degradation, 1,3,5-Triazine-2,4,6-triamine is considered to be not readily biodegradable in nature.

 

For the same read across chemical 1,3,5-Triazine-2,4,6-triamine (CAS no. 108-78-1),a standard BOD test for 5 days was conducted under aerobic conditions for evaluating the percentage biodegradability of read across substance 1,3,5-Triazine-2,4,6-triamine (HSDB, 2017). The percentage degradation of substance 1,3,5-Triazine-2,4,6-triamine was determined to be 0% by BOD parameter in 5 days. Thus, based on percentage degradation, 1,3,5-Triazine-2,4,6-triamine is considered to be not readily biodegradable in nature.

 

In a supporting weight of evidence study from authoritative database (J-CHECK, 2017 and EnviChem, 2014) for the read across chemical 2-Isopropyl-6-methyl-4-pyrimidinol (CAS no. 2814-20-2), biodegradation experiment was conducted for 28 days for evaluating the percentage biodegradability of read across substance 2-Isopropyl-6-methyl-4-pyrimidinol. The study was performed according to OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I)). Concentration of inoculum i.e, sludge used was 30 mg/l and initial test substance conc. used in the study was 100 mg/l, respectively. The percentage degradation of substance 2-Isopropyl-6-methyl-4-pyrimidinol was determined to be 0 and 2% by BOD, TOC removal and HPLC parameter in 28 days. Thus, based on percentage degradation, 2-Isopropyl-6-methyl-4-pyrimidinol is considered to be not readily biodegradable in nature.

 

On the basis of above results for target chemical 2-Hydroxypyridine 1-oxide (from OECD QSAR toolbox version 3.3 and EPI suite, 2017) and for its read across substance (from authoritative database J-CHECK, HSDB, EnviChem and peer reviewed journal), it can be concluded that the test substance 2-Hydroxypyridine 1-oxide can be expected to be not readily biodegradable in nature.