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Biodegradation in water: screening tests

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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 3.4 with logKow as the primary descriptor.
GLP compliance:
not specified
Specific details on test material used for the study:
- Name of test material : 1,4-bis[(2-methylphenyl)amino]anthraquinone
- Molecular formula : C28H22N2O2
- Molecular weight : 418.494 g/mol
- Smiles notation : c1cc2C(=O)c3c(C(=O)c2cc1)c(Nc1ccccc1C)ccc3Nc1c(cccc1)C
- InChl : 1S/C28H22N2O2/c1-17-9-3-7-13-21(17)29-23-15-16-24(30-22-14-8-4-10-18(22)2)26-25(23)27(31)19-11-5-6-12-20(19)28(26)32/h3-16,29-30H,1-2H3
- 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:
0.2
Sampling time:
28 d
Remarks on result:
other: Other details not known
Details on results:
Test substance undergoes 0.2% 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" )  and "c" )  and "d" )  and ("e" and "f" )  )

Domain logical expression index: "a"

Referential boundary: The target chemical should be classified as AN2 AND AN2 >>  Michael-type addition, quinoid structures AND AN2 >>  Michael-type addition, quinoid structures >> Quinones and Trihydroxybenzenes AND Non-covalent interaction AND Non-covalent interaction >> DNA intercalation AND Non-covalent interaction >> DNA intercalation >> Quinones and Trihydroxybenzenes AND Radical AND Radical >> Radical mechanism via ROS formation (indirect) AND Radical >> Radical mechanism via ROS formation (indirect) >> Quinones and Trihydroxybenzenes by DNA binding by OASIS v.1.4

Domain logical expression index: "b"

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  >> N-Substituted Aromatic Amines by Protein binding by OASIS v1.4

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as Does NOT Biodegrade Fast by Biodeg probability (Biowin 1) ONLY

Domain logical expression index: "d"

Referential boundary: The target chemical should be classified as months and longer by Biodeg ultimate (Biowin 3) ONLY

Domain logical expression index: "e"

Parametric boundary:The target chemical should have a value of Molecular weight which is >= 405 Da

Domain logical expression index: "f"

Parametric boundary:The target chemical should have a value of Molecular weight which is <= 627 Da

Validity criteria fulfilled:
not specified
Interpretation of results:
under test conditions no biodegradation observed
Conclusions:
The test chemical 1,4-bis[(2-methylphenyl)amino]anthraquinone was estimated to be not readily biodegradable in water.
Executive summary:

Biodegradability of 1,4-bis[(2-methylphenyl)amino]anthraquinone (CAS no. 6737 -68 -4) is predicted using QSAR toolbox version 3.4 with logKow as the primary descriptor. Test substance undergoes 0.2% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical 1,4-bis[(2-methylphenyl)amino]anthraquinone was estimated to be not readily biodegradable in water.

Description of key information

Biodegradability of1,4-bis[(2-methylphenyl)amino]anthraquinone(CAS no. 6737 -68 -4) is predicted using QSAR toolbox version 3.4 (2017) with logKow as the primary descriptor. Test substance undergoes 0.2% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical1,4-bis[(2-methylphenyl)amino]anthraquinonewas 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 1,4-bis[(2-methylphenyl)amino]anthraquinone (CAS No. 6737-68-4) and supporting weight of evidence studies for its structurally similar 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 3.4 with logKow as the primary descriptor, percentage biodegradability of test chemical 1,4 -bis[(2 -methylphenyl) amino]anthraquinone(CAS No. 6737 -68 -4) was estimated.Test substance undergoes 0.2% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical1,4-bis[(2-methylphenyl)amino]anthraquinonewas 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 compound1,4-bis[(2-methylphenyl)amino]anthraquinone(CAS No. 6737-68-4) 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 chemical1,4-bis[(2-methylphenyl)amino]anthraquinoneis expected to be not readily biodegradable.

 

In a supporting weight of evidence study from authoritative database (HSDB, 2017) for the read across chemical Alizarin Cyanin Green F (CAS no. 4403-90-1), biodegradation experiment was conducted for 5 days for evaluating the percentage biodegradability of read across substance Alizarin Cyanin Green F (CAS no. 4403-90-1) using 5 day BOD test under aerobic conditions. Sewage sludge was used as a test inoculum. Initial test substance conc. used in the study was 2.5 mg/l. The percentage degradation of substance Alizarin Cyanin Green F was determined to be 0% by BOD parameter in 5 days. Thus, based on percentage degradation, Alizarin Cyanin Green F is considered to be not readily biodegradable in nature.

 

Another biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of read across substance 7,12-dihydrotetraphene-7,12-dione (CAS no. 2498-66-0) (J-CHECK, 2017 and EnviChem, 2014). The study was performed according to OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I). Activated sludge was used as a test inoculums for the study. 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 7,12 -dihydrotetraphene-7,12 -dione was determined to be 1 and 3% by BOD and HPLC parameter in 28 days. Thus, based on percentage degradation, 7,12 -dihydrotetraphene-7,12 -dione is considered to be not readily biodegradable in nature.

 

For the read across chemical 1-N,4-N-diphenylbenzene-1,4-diamine (CAS no. 74-31-7) from authoritative database (J-CHECK and HSDB, 2017 & EnviChem, 2014), biodegradation study was conducted for 14 days for evaluating the percentage biodegradability of read across substance 1-N,4-N-diphenylbenzene-1,4-diamine. The study was performed according to OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I)) under aerobic conditions. 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-N,4-N-diphenylbenzene-1,4-diamine was determined to be 0.2 and 0.3% by BOD and GC parameter in 14 days. Thus, based on percentage degradation,1-N,4-N-diphenylbenzene-1,4-diamine is considered to be not readily biodegradable in nature.

 

On the basis of above results for target chemical 1,4-bis[(2-methylphenyl)amino]anthraquinone (from OECD QSAR toolbox version 3.4 and EPI suite, 2017) and for its read across substance (from authoritative database J-CHECK, HSDB and EnviChem), it can be concluded that the test substance 1,4-bis[(2-methylphenyl)amino]anthraquinone can be expected to be not readily biodegradable in nature.