3,7-bis(diethylamino)phenoxazin-5-ium acetate

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:

Data is from OECD QSAR toolbox version 3.3 and the 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:

Prediction was done 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): 3,7-bis(diethylamino)phenoxazin-5-ium acetate
- Molecular formula: C22H29N3O3
- Molecular weight: 383.489 g/mol
- Smiles notation: c1c2nc3ccc(cc3[o+]c2cc(N(CC)CC)c1)N(CC)CC.C(C)(=O)[O-]
- InChl: 1S/C20H26N3O.C2H4O2/c1-5-22(6-2)15-9-11-17-19(13-15)24-20-14-16(23(7-3)8-4)10-12-18(20)21-17;1-2(3)4/h9-14H,5-8H2,1-4H3;1H3,(H,3,4)/q+1;/p-1
- Substance type: Organic
- Physical state:

Oxygen conditions:

aerobic

Inoculum or test system:

other: Microorganisms

Details on inoculum:

No data available

Duration of test (contact time):

28 d

Based on:

not specified

Parameter followed for biodegradation estimation:

other: BOD

Key result

Parameter:

other: BOD

Value:

0.767

Sampling time:

28 d

Remarks on result:

other: Other details not known

Details on results:

Test substance undergoes 0.7666 % 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 6 nearest neighbours
Domain  logical expression:Result: In Domain

(((((("a" or "b" )  and "c" )  and "d" )  and "e" )  and "f" )  and ("g" and "h" )  )

Domain logical expression index: "a"

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

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as Peroxy Acids by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as weeks - months by Biodeg primary (Biowin 4) ONLY

Domain logical expression index: "d"

Referential boundary: The target chemical should be classified as No alert found by DNA binding by OASIS v.1.3 ONLY

Domain logical expression index: "e"

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

Domain logical expression index: "f"

Referential boundary: The target chemical should be classified as Class 5 (Not possible to classify according to these rules) by Acute aquatic toxicity classification by Verhaar (Modified) ONLY

Domain logical expression index: "g"

Parametric boundary:The target chemical should have a value of Molecular weight which is >= 254 Da

Domain logical expression index: "h"

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 3,7-bis(diethylamino)phenoxazin-5-ium acetate was estimated to be not readily biodegradable in water.

Executive summary:

Biodegradability of 3,7-bis(diethylamino)phenoxazin-5-ium acetate (CAS no.79916 -07 -7) is predicted using OECD QSAR toolbox version 3.3 with logKow as the primary descriptor. Test substance undergoes 0.7666 % degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical 3,7-bis(diethylamino) phenoxazin-5-ium acetate was estimated to be not readily biodegradable in water.

Description of key information

Biodegradability of 3,7-bis(diethylamino)phenoxazin-5-ium acetate (CAS no.79916 -07 -7) is predicted using OECD QSAR toolbox version 3.3 with logKow as the primary descriptor. Test substance undergoes 0.7666 % degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical 3,7-bis(diethylamino) phenoxazin-5-ium acetate 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 and experimental data for the target compound 3,7-bis(diethylamino)phenoxazin-5-ium acetate (79916-07-7) 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 3,7-bis(diethylamino) phenoxazin-5-ium acetate was estimated. Biodegradability of 3,7-bis(diethylamino)phenoxazin-5-ium acetate (CAS no.79916 -07 -7) is predicted using OECD QSAR toolbox version 3.3 with logKow as the primary descriptor. Test substance undergoes 0.7666 % degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical 3,7-bis(diethylamino) phenoxazin-5-ium acetate was estimated to be not readily biodegradable in water. 

In a supporting weight of evidence study from peer reviewed journal (Fresenius Z. Anal. Chem, 1984) for the read across chemical (2465-27-2). Biodegradation study was conducted for evaluating the percentage biodegradability of test substance 4,4'-carbonimidoylbis(N,N-dimethylaniline) hydrochloride. (CAS no. 2465-27-2). Activated sludge was used as a test inoculum obtained from municipal sewage. Test substance of conc. 500 mg/l was prepared and diluted as needed.The COD measurement was performed by the potassium dichromate reflux method based on Japanese Industrial Standards. In the BOD measurement, a sample solution was taken into a container. Then JIS-BOD testing solutions, i.e. 3 ml of A solution and 1 ml of B, C, D solutions were added to the sample solution, respectively. Then 5 ml of the supernatant of the municipal sewage activated sludge was added to the sample solution and diluted to 300 ml with water. Immediately, the BOD-time curve was recorded at 20~ using an Ohkura OM-200I type coulometer. The TOC measurement was carried out by a Yanagimoto TOC-ILW.BOD5, COD, ThOD and TOC value of the test chemical was determined to be 0.038, 1.42, 2.50 and 0.32 g/g, respectively. The BOD5/TOC ratio of test chemical was determined to be 0.12 (i.e. ranges in between 0.08-0.89), indicating that the chemical is highly resistant to aerobic biodegradation. Thus, based on this value BOD5/TOC value, it can be concluded that the test chemical 4,4'-carbonimidoylbis(N,N-dimethylaniline) hydrochloride is not readily biodegradable in nature.

 

Similarly another biodegradation study for read across chemical which was structurally similar to the target chemical (from authoritative database J-CHECK, 2017), was conducted. Biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of test substance C.I. Solvent Red 49 (CAS no. 509 -34 -2). 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 test substance was determined to be 0 and 1% degradation by BOD, TOC removal and HPLC in 28 days.  Thus, based on percentage degradation, C.I. Solvent Red 49 was considered to be not readily biodegradable in nature.

 

In a fifth supporting weight of evidence study from authoritative databases for RA cas (81-88-9) from j-check 2017 was consider as the structurally similarities with target chemical Biodegradation screening study is conducted for 4 weeks. 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 test substance is 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 Rhodamine B is considered to be not readily biodegradable in nature.

 

On the basis of above results for target chemical 3,7-bis(diethylamino)phenoxazin-5-ium acetate (79916-07-7) (from OECD QSAR toolbox version 3.3 and EPI suite, 2017) and for its read across substance peer reviewed journal and authoritative from database J-CHECK, it can be concluded that the test substance 3,7-bis(diethylamino)phenoxazin- 5-ium acetate can be expected to be not readily biodegradable in nature.