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Environmental fate & pathways

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Description of key information

Biodegradation in water:

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.

Biodegradation in water and sediment:

Estimation Programs Interface (EPI Suite, 2017) prediction model was run to predict the half-life in water and sediment for the test compound 3,7-bis(diethylamino) phenoxazin-5-ium acetate (CAS no.79916 -07 -7). If released in to the environment,3.66% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of   3,7-bis(diethylamino)phenoxazin-5-ium acetate (CAS no.79916 -07 -7) in water is estimated to be 60 days (1440 hrs). The half-life (60 days estimated by EPI suite) indicates that the chemical is persistent in water and the exposure risk to aquatic animals is high whereas the half-life period of   3,7-bis(diethylamino)phenoxazin-5-ium acetate in sediment is estimated to be 541.66  days (13000 hrs). Based on this half-life value, it indicates that 3,7-bis(diethylamino)phenoxazin-5-ium acetate is persistent in sediment.

 

Biodegradation in soil:

The half-life period of 3,7-bis(diethylamino)phenoxazin-5-ium acetate (CAS no.79916 -07 -7) in soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database (EPI suite, 2017). If released into the environment, 58.7 % of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of 3,7-bis(diethylamino)phenoxazin-5-ium acetate in soil is estimated to be 120 days ( 2880 hrs). Based on this half-life value of 3,7-bis(diethylamino)phenoxazin-5-ium acetate, it is concluded that the chemical is not persistent in the soil environment and the exposure risk to soil dwelling animals is low.

Additional information

Biodegradation in water:

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.

 

 

 

Biodegradation in water and sediment:

 

Estimation Programs Interface (EPI Suite, 2017) prediction model was run to predict the half-life in water and sediment for the test compound 3,7-bis(diethylamino) phenoxazin-5-ium acetate (CAS no.79916 -07 -7). If released in to the environment,3.66% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of   3,7-bis(diethylamino)phenoxazin-5-ium acetate (CAS no.79916 -07 -7) in water is estimated to be 60 days (1440 hrs). The half-life (60 days estimated by EPI suite) indicates that the chemical is persistent in water and the exposure risk to aquatic animals is high whereas the half-life period of   3,7-bis(diethylamino)phenoxazin-5-ium acetate in sediment is estimated to be 541.66  days (13000 hrs). Based on this half-life value, it indicates that 3,7-bis(diethylamino)phenoxazin-5-ium acetate is persistent in sediment.

 

Biodegradation in soil:

The half-life period of 3,7-bis(diethylamino)phenoxazin-5-ium acetate (CAS no.79916 -07 -7) in soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database (EPI suite, 2017). If released into the environment, 58.7 % of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of 3,7-bis(diethylamino)phenoxazin-5-ium acetate in soil is estimated to be 120 days ( 2880 hrs). Based on this half-life value of 3,7-bis(diethylamino)phenoxazin-5-ium acetate, it is concluded that the chemical is not persistent in the soil environment and the exposure risk to soil dwelling animals is low.