9-[2-(ethoxycarbonyl)phenyl]-3,6-bis(ethylamino)-2,7-dimethylxanthylium, salt with 4,5-dihydro-5-oxo-1-(4-sulphophenyl)-4-[(4-sulphophenyl)azo]-1H-pyrazole-3-carboxylic acid (3:1)

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): 9-[2-(ethoxycarbonyl)phenyl]-3,6-bis(ethylamino)-2,7-dimethylxanthylium
- Molecular formula: C28H31N2O3.1/3C16H9N4O9S2
- Molecular weight: 1796.09 g/mol
- Smiles notation: c1(C)c(cc2[o+]c3c(c(c4c(cccc4)C(OCC)=O)c2c1)cc(C)c(NCC)c3)NCC.C1([C@@H](\N=N/c2ccc(cc2)S([O-])(=O)=O)C(=NN1c1ccc(S([O-])(=O)=O)cc1)C([O-])=O)=O.c1(cc2c([o+]c3c(c2c2ccccc2C(OCC)=O)cc(c(NCC)c3)C)cc1NCC)C.c1(cc2c([o+]c3c(c2c2ccccc2C(OCC)=O)cc(c(NCC)c3)C)cc1NCC)C
- InChl: 1S/3C28H31N2O3.C16H12N4O9S2/c3*1-6-29-23-15-25-21(13-17(23)4)27(19-11-9-10-12-20(19)28(31)32-8-3)22-14-18(5)24(30-7-2)16-26(22)33-25;21-15-13(18-17-9-1-5-11(6-2-9)30(24,25)26)14(16(22)23)19-20(15)10-3-7-12(8-4-10)31(27,28)29/h3*9-16,29-30H,6-8H2,1-5H3;1-8,13H,(H,22,23)(H,24,25,26)(H,27,28,29)/q3*+1;/p-3/b;;;18-17-
- 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:

8.2

Sampling time:

28 d

Remarks on result:

other: Other details not known

Details on results:

Test substance undergoes 8.20% 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" )  and "e" )  and ("f" and "g" )  )

Domain logical expression index: "a"

Referential boundary: The target chemical should be classified as Esters (Chronic toxicity) AND Not categorized by US-EPA New Chemical Categories

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as No alert found AND Non-specific AND Non-specific >> Incorporation into DNA/RNA, due to structural analogy with  nucleoside bases    AND Non-specific >> Incorporation into DNA/RNA, due to structural analogy with  nucleoside bases    >> Specific Imine and Thione Derivatives AND Radical AND Radical >> Radical mechanism via ROS formation (indirect) AND Radical >> Radical mechanism via ROS formation (indirect) >> Specific Imine and Thione Derivatives AND SN1 AND SN1 >> Nucleophilic substitution on diazonium ions AND SN1 >> Nucleophilic substitution on diazonium ions >> Specific Imine and Thione Derivatives by DNA binding by OASIS v.1.3

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as No alert found AND SN1 AND SN1 >> Nitrenium Ion formation AND SN1 >> Nitrenium Ion formation >> Secondary aromatic amine by DNA binding by OECD

Domain logical expression index: "d"

Referential boundary: The target chemical should be classified as Esters OR Inorganic Compound OR Schiff Bases-Azomethine OR Vinyl/Allyl Ethers by Aquatic toxicity classification by ECOSAR ONLY

Domain logical expression index: "e"

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

Domain logical expression index: "f"

Parametric boundary:The target chemical should have a value of Molecular weight which is >= 415 Da

Domain logical expression index: "g"

Parametric boundary:The target chemical should have a value of Molecular weight which is <= 517 Da

Validity criteria fulfilled:

not specified

Interpretation of results:

not readily biodegradable

Conclusions:

The test chemical 9-[2-(ethoxycarbonyl)phenyl]-3,6-bis(ethylamino)-2,7-dimethylxanthylium was estimated to be not readily biodegradable in water.

Executive summary:

Biodegradability of 9-[2-(ethoxycarbonyl)phenyl]-3,6-bis(ethylamino)-2,7-dimethylxanthylium (CAS no. 65138 -66 -1) is predicted using OECD QSAR toolbox version 3.3 with logKow as the primary descriptor. Test substance undergoes 8.20% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical 9 -[2 -(ethoxycarbonyl) phenyl]-3,6 -bis(ethylamino)-2,7 -dimethylxanthylium was estimated to be not readily biodegradable in water.

Description of key information

Biodegradability of 9-[2-(ethoxycarbonyl)phenyl]-3,6-bis(ethylamino)-2,7-dimethylxanthylium (CAS no. 65138 -66 -1) is predicted using OECD QSAR toolbox version 3.3 (2017) with logKow as the primary descriptor. Test substance undergoes 8.20% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical 9 -[2 -(ethoxycarbonyl) phenyl]-3,6 -bis(ethylamino)-2,7 -dimethylxanthylium 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

Predicted data for the target compound 9-[2-(ethoxycarbonyl)phenyl]-3,6-bis(ethylamino)-2,7-dimethylxanthylium (CAS No. 65138-66-1) 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 9 -[2 -(ethoxy carbonyl)phenyl]-3,6 -bis(ethylamino)-2,7 -dimethylxanthylium(CAS No. 65138-66-1) was estimated.Test substance undergoes 8.20% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical 9 -[2 -(ethoxycarbonyl) phenyl]-3,6 -bis(ethylamino)-2,7 -dimethylxanthylium was estimated to be not readily biodegradable in water.

 

In a supporting weight of evidence study from authoritative database (J-CHECK, 2016) for the read across chemical 3',6'-Bbis(diethylamino)spiro[isobenzofuran-1(3h),9'-[9h] xanthene]-3-one (CAS no. 509-34-2), biodegradation experiment was conducted for 28 days for evaluating the percentage biodegradability of read across substance 3',6'-Bbis(diethylamino)spiro[isobenzofuran-1(3h),9'-[9h] xanthene]-3-one. Concentration of inoculum i.e, sludge used was 30 mg/l and initial test substance conc. used in the study was 100 mg/l. The percentage degradation of read across substance 3',6'-Bbis(diethylamino)spiro[isobenzofuran-1(3h),9'-[9h]xanthene]-3-one was determined to be 0 and 1% degradation by BOD, TOC removal and HPLC in 28 days.  Thus, based on percentage degradation, 3',6'-Bbis(diethylamino)spiro[isobenzofuran-1(3h),9'-[9h]xanthene]- 3 -one was 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 9-(2-carboxyphenyl)-3,6-bis(diethylamino) xanthenium chloride (CAS no. 81-88-9) (J-CHECK, 2017) . Concentration of inoculum i.e, sludge was 30 mg/l and initial test substance conc. used in the study was 100 mg/l, respectively. The percentage degradation of substance 9-(2-carboxyphenyl)-3,6-bis(diethylamino)xanthenium chloride was determined to be 0, 2 and 7% degradation by BOD, TOC removal and Uv-Vis parameter in 28 days. Thus, based on percentage degradation, substance 9 -(2 -carboxyphenyl)-3,6 -bis(diethylamino)xanthenium chloride is considered to be not readily biodegradable in nature.

 

For the read across chemical 2 -[(2-cyanoethyl){4-[(4-nitrophenyl)diazenyl]phenyl}amino]ethyl benzoate (CAS no. 40690-89-9) from authoritative database (J-CHECK, 2017 and EnviChem, 2014), biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of read across substance 2 -[(2 -cyanoethyl){4 -[(4 -nitrophenyl)diazenyl]phenyl}amino] ethyl benzoate. 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 -[(2 -cyanoethyl){4 -[(4 -nitrophenyl)diazenyl]phenyl}amino]ethyl benzoate was determined to be 6% by both BOD and HPLC parameter in 28 days. Thus, based on percentage degradation, 2 -[(2 -cyanoethyl){4 -[(4 -nitrophenyl)diazenyl]phenyl}amino]ethyl benzoate is considered to be not readily biodegradable in nature.

 

On the basis of above results for target chemical9-[2-(ethoxycarbonyl)phenyl]-3,6-bis(ethylamino)-2,7-dimethylxanthylium(from OECD QSAR toolbox version 3.3, 2017) and for its read across substance (from authoritative database J-CHECK and EnviChem), it can be concluded that the test substance 9 -[2 -(ethoxycarbonyl)phenyl]-3,6 -bis(ethylamino)- 2,7 -dimethylxanthyliumcan be expected to be not readily biodegradable in nature.