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Biodegradation in water: screening tests

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Reference
Endpoint:
biodegradation in water: screening tests
Type of information:
calculation (if not (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:
equivalent or similar to
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:
- IUPAC name 2-methyl-4-nitroaniline
- Name of test material: 4-nitro-o-toluidine
- Molecular formula: C7H8N2O2
- Molecular weight: 152.152 g/mol
- Physical state: Solid
- SMILES: c1(cc(c(N)cc1)C)[N+](=O)[O-]
- InChI: 1S/C7H8N2O2/c1-5-4-6(9(10)11)2-3-7(5)8/h2-4H,8H2,1H3
Oxygen conditions:
aerobic
Inoculum or test system:
other: Microorganisms
Duration of test (contact time):
28 d
Parameter followed for biodegradation estimation:
other: BOD
Key result
Parameter:
other: BOD
Value:
0.243
Sampling time:
28 d
Remarks on result:
other: Other details not known
Details on results:
Test substance undergoes 0.24% 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 7 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 "m" )  and ("n" and ( not "o") )  )  and ("p" and "q" )  )

Domain logical expression index: "a"

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

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as Alkyl arenes AND Aniline AND Aryl AND Nitrobenzene by Organic Functional groups

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as Alkyl arenes AND Aniline AND Nitrobenzene AND Overlapping groups by Organic Functional groups (nested)

Domain logical expression index: "d"

Referential boundary: The target chemical should be classified as Aliphatic Carbon [CH] AND Aliphatic Carbon [-CH2-] AND Aliphatic Carbon [-CH3] AND Aliphatic Nitrogen, one aromatic attach [-N] AND Aromatic Carbon [C] AND Miscellaneous sulfide (=S) or oxide (=O) AND Nitro, aromatic attach [-NO2] AND Olefinic carbon [=CH- or =C<] by Organic functional groups (US EPA)

Domain logical expression index: "e"

Referential boundary: The target chemical should be classified as Amine AND Aromatic compound AND Nitro compound AND Primary amine AND Primary aromatic amine by Organic functional groups, Norbert Haider (checkmol)

Domain logical expression index: "f"

Referential boundary: The target chemical should be classified as SN1 AND SN1 >> Nitrenium Ion formation AND SN1 >> Nitrenium Ion formation >> Aromatic nitro AND SN1 >> Nitrenium Ion formation >> Primary aromatic amine by DNA binding by OECD

Domain logical expression index: "g"

Referential boundary: The target chemical should be classified as No alert found OR SN1 >> Iminium Ion Formation OR SN1 >> Iminium Ion Formation >> Aliphatic tertiary amines OR SN1 >> Nitrenium Ion formation >> Aromatic azo OR SN1 >> Nitrenium Ion formation >> Tertiary aromatic amine by DNA binding by OECD

Domain logical expression index: "h"

Referential boundary: The target chemical should be classified as Weak binder, NH2 group by Estrogen Receptor Binding

Domain logical expression index: "i"

Referential boundary: The target chemical should be classified as Moderate binder, NH2 group OR Non binder, impaired OH or NH2 group OR Non binder, MW>500 OR Non binder, without OH or NH2 group OR Strong binder, NH2 group OR Strong binder, OH group OR Weak binder, OH group by Estrogen Receptor Binding

Domain logical expression index: "j"

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

Domain logical expression index: "k"

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

Domain logical expression index: "l"

Referential boundary: The target chemical should be classified as Does NOT Biodegrade Fast by Biodeg probability (Biowin 5) ONLY

Domain logical expression index: "m"

Similarity boundary:Target: Cc1cc(N(=O)=O)ccc1N
Threshold=40%,
Dice(Atom centered fragments)
Atom type; Count H attached; Hybridization

Domain logical expression index: "n"

Referential boundary: The target chemical should be classified as Basic [0,10) AND No pKa value by Ionization at pH = 7.4

Domain logical expression index: "o"

Referential boundary: The target chemical should be classified as Acidic [0,10) OR Basic [10,20) by Ionization at pH = 7.4

Domain logical expression index: "p"

Parametric boundary:The target chemical should have a value of Molecular weight which is >= 135 Da

Domain logical expression index: "q"

Parametric boundary:The target chemical should have a value of Molecular weight which is <= 169 Da

Validity criteria fulfilled:
not specified
Interpretation of results:
under test conditions no biodegradation observed
Conclusions:
The test chemical 2-methyl-4-nitroaniline was estimated to be not readily biodegradable in water.
Executive summary:

Biodegradability of 2-methyl-4-nitroaniline (CAS no. 99 -52 -5) is predicted using QSAR toolbox version 3.3 with logKow as the primary descriptor (2017). Test substance undergoes 0.24% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical 2-methyl-4-nitroaniline was estimated to be not readily biodegradable in water.

Description of key information

Biodegradability of 2-methyl-4-nitroaniline (CAS no. 99-52-5) is predicted using QSAR toolbox version 3.3 with logKow as the primary descriptor (2017). Test substance undergoes 0.24% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical 2-methyl-4-nitroaniline 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-methyl-4-nitroaniline(CAS No. 99-52-5) and weight of evidence studies for its read across substance 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-methyl-4-nitroaniline(CAS No. 99-52-5) was estimated (2017).Test substance undergoes 0.24% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical 2-methyl-4-nitroaniline was estimated to be not readily biodegradable in water.

 

In another prediction using the Estimation Programs Interface Suite (EPI suite, 2017), the biodegradation potential of the test compound 2-methyl-4-nitroaniline (CAS No. 99-52-5) in the presence of mixed populations of environmental microorganisms 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 2-methyl-4-nitroaniline is expected to be not readily biodegradable.

 

In a supporting weight of evidence study from authoritative database (J-CHECK. 2016), biodegradation experiment was conducted for 28 days for evaluating the percentage biodegradability of read across substance1,5 -naphthalinediamine (CAS no. 2243 -62 -1). 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 read across substance was determined to be 0 and 3% degradation by BOD and HPLC parameter in 28 days. Thus, based on percentage degradation, 1,5 -naphthalinediamine is considered to be not readily biodegradable in nature.

 

For another read across chemical naphthalene-1,8 -diamine (CAS no. 479 -27 -6), biodegradation experiment was conducted for 28 days for evaluating the percentage biodegradability of test substance naphthalene-1,8 -diamine (J-CHECK, 2016). 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 read across substance was determined to be 0, 9 and 1% by BOD, TOC removal and HPLC parameter in 28 days. Thus, based on percentage degradation, naphthalene-1,8 -diamine is considered to be not readily biodegradable in nature.

 

On the basis of above results for target chemical 2-methyl-4-nitroaniline (from OECD QSAR toolbox version 3.3 and EPI Suite, 2017) and for its read across substance (from authoritative database J-CHECK, 2016), it can be concluded that the test substance 2-methyl-4-nitroaniline can be expected to be not readily biodegradable in nature.