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Toxicity to microorganisms

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Reference
Endpoint:
toxicity to microorganisms
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 QMRF report has been attached.
Reference:
Composition 0
Qualifier:
according to
Guideline:
other: predicted data
Principles of method if other than guideline:
Prediction is done using QSAR Toolbox version 3.3 with log kow as the primary discriptors.
GLP compliance:
not specified
Test material information:
Composition 1
Specific details on test material used for the study:
- Name of test material: p-Methylaminophenol sulfate- IUPAC name: Bis(4-hydroxy-N-methylanilinium) sulphate- Molecular formula: C14H20N2O6S- Molecular weight: 344.386 g/mole- Smiles:CNc1ccc(cc1)O.CNc1ccc(cc1)O.OS(=O)(=O)O- Inchl: 1S/2C7H9NO.H2O4S/c2*1-8-6-2-4-7(9)5-3-6;1-5(2,3)4/h2*2-5,8-9H,1H3;(H2,1,2,3,4)- Substance type: Organic- Physical state: Solid crystalline (off white - white)
Analytical monitoring:
not specified
Vehicle:
not specified
Test organisms (species):
Tetrahymena pyriformis
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h
Key result
Duration:
48 h
Dose descriptor:
other: IGC50
Effect conc.:
59.84 mg/L
Nominal / measured:
estimated
Conc. based on:
test mat.
Basis for effect:
other: Growth
Remarks on result:
other: toxic

The prediction was based on dataset comprised from the following descriptors: IGC50
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 "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" )  )

Domain logical expression index: "a"

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

Domain logical expression index: "b"

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

Domain logical expression index: "c"

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

Domain logical expression index: "d"

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

Domain logical expression index: "e"

Referential boundary: The target chemical should be classified as Not possible to classify according to these rules by DPRA Cysteine peptide depletion

Domain logical expression index: "f"

Referential boundary: The target chemical should be classified as High reactive OR High reactive >> Activated haloarenes OR High reactive >> Aromatic C-Nitroso compounds OR High reactive >> Benzyl halides OR Low reactive OR Low reactive >> N-substituted aromatic amides by DPRA Cysteine peptide depletion

Domain logical expression index: "g"

Referential boundary: The target chemical should be classified as Class 3 (unspecific reactivity) by Acute aquatic toxicity classification by Verhaar (Modified) ONLY

Domain logical expression index: "h"

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

Domain logical expression index: "i"

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

Domain logical expression index: "j"

Referential boundary: The target chemical should be classified as Anilines (Hindered) OR Anilines (Unhindered) OR Esters OR Hydroquinones OR Phenol Amines OR Phenols by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "k"

Referential boundary: The target chemical should be classified as Aromatic Amine Type Compounds AND Phenol Type Compounds by Oncologic Primary Classification

Domain logical expression index: "l"

Referential boundary: The target chemical should be classified as Halogenated Aromatic Hydrocarbon Type Compounds by Oncologic Primary Classification

Domain logical expression index: "m"

Referential boundary: The target chemical should be classified as H-acceptor-path3-H-acceptor by in vivo mutagenicity (Micronucleus) alerts by ISS

Domain logical expression index: "n"

Referential boundary: The target chemical should be classified as Nitro-aromatic by in vivo mutagenicity (Micronucleus) alerts by ISS

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 OR 1 to 10 days by Ultimate biodeg

Domain logical expression index: "q"

Parametric boundary:The target chemical should have a value of log Kow which is >= 0.966

Domain logical expression index: "r"

Parametric boundary:The target chemical should have a value of log Kow which is <= 4.85

Conclusions:
Based on the prediction done using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the closest read across substances, the toxicity on micro-organisms was predicted Bis(4-hydroxy-N-methylanilinium) sulphate (CAS:55-55-0). Growth inhibition concentration i.e IGC50 value was estimated to be 59.84 mg/l for Tetrahymena pyriformis for 48 hrs duration. It was concluded that the Bis(4-hydroxy-N-methylanilinium) sulphate (CAS: 55-55-0) was likely to be toxic to micro-organisms
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 closest read across substances, the toxicity on micro-organisms was predicted Bis(4-hydroxy-N-methylanilinium) sulphate (CAS:55-55-0). Growth inhibition concentration i.e IGC50 value was estimated to be 59.84 mg/l for Tetrahymena pyriformis for 48 hrs duration. It was concluded that the Bis(4-hydroxy-N-methylanilinium) sulphate (CAS: 55-55-0) was likely to be toxic to micro-organisms

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 closest read across substances, the toxicity on micro-organisms was predicted Bis(4-hydroxy-N-methylanilinium) sulphate (CAS:55-55-0). Growth inhibition concentration i.e IGC50 value was estimated to be 59.84 mg/l for Tetrahymena pyriformis for 48 hrs duration. It was concluded that the Xanthylium, 9-[2-(ethoxycarbonyl)phenyl]-3,6-bis(ethylamino)-2,7-dimethyl-, molybdatesilicate (CAS: 63022) was likely to be toxic to micro-organisms

Key value for chemical safety assessment

EC50 or LC50 for microorganisms:
59.84 mg/L

Additional information

Following studies include the predicted data and experimental study for the target chemical and structurally similar read across to conclude the toxicity extent of 4-aminophenol (CAS: 55-55-0) towards aquatic algae is summarized as follows:

Based on the prediction done using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the closest read across substances, the toxicity on micro-organisms was predicted Bis(4-hydroxy-N-methylanilinium) sulphate (CAS:55-55-0). Growth inhibition concentration i.e IGC50 value was estimated to be 59.84 mg/l for Tetrahymena pyriformis for 48 hrs duration. It was concluded that the Xanthylium, 9-[2-(ethoxycarbonyl)phenyl]-3,6-bis(ethylamino)-2,7-dimethyl-, molybdatesilicate (CAS: 63022) was likely to be toxic to micro-organisms

Further it is supported by the experimental study of structurally similar read across 4-aminophenol (CAS: 123-30-8) from the publication Fresenius Environmental Bulletin 2011,The study was carried out according to the broth macrodilution method to investigate the antibacterial potentials of p-aminophenol. PH of the growth medium had a slight effect on the MIC values and the MIC value was higher in the growth medium with a lower pH. Time-kill analyses of p-aminophenol were performed against Staphylococcus aureus and concn. dependent killing curves were obtained.

The results demonstrated that p-aminophenol could inhibit the bacterial growth.

Minimum inhibitory concentration(MIC) to Staphylococcus aureus is 3.125 mg/L. It  can be concluded from the value that the  p-aminophenol is toxic to the micro-organisms.

Thus based on the effect concentrations which is in the range 3.125 mg/l to 59.84 mg/l give the conclusion that test substance 4-aminophenol (CAS: 55-55-0) was likely to be toxic to micro-organism at environmentally relevant concentrations and applying weight of evidence approach it can be considered to be toxic as per the CLP classification criteria for aquatic environment.