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Biodegradation in water:

Biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of test substance (4-(4-aminophenyl)(4-imino -cyclohexa-2,5-dienylidene) methyl)-2-methylaniline hydrochloride. (CAS no. 632-99-5). 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 test substance was determined to 0, 13 and 2% by BOD, TOC, and HPLC parameter in 28 days. Thus, based on percentage degradation, (4-(4-aminophenyl)(4-imino -cyclohexa-2,5-dienylidene) methyl)-2-methylaniline hydrochloride is considered 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 (4-(4-aminophenyl) (4-iminocyclohexa-2, 5- dienylidene)methyl)-2-methylaniline hydrochloride (CAS No. 632 -99 -5). If released in to the environment, 3.02 % of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of (4-(4-aminophenyl)(4-iminocyclohexa-2,5-dienylidene)methyl) -2-methylaniline hydrochloride 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 moderate to high whereas the half-life period of (4-(4-aminophenyl) (4-iminocyclohexa-2,5-dienylidene)methyl)-2- methylaniline hydrochloride in sediment is estimated to be 541.66 days (13000 hrs). Based on this half-life value, it indicates that (4-(4-aminophenyl)(4-iminocyclohexa-2,5- dienylidene)methyl)-2-methylaniline hydrochloride is persistent in sediment.

Biodegradation in soil:

The half-life period of (4-(4-aminophenyl)(4-iminocyclohexa-2,5-dienylidene)methyl)-2-methylaniline hydrochloride (632 -99 -5) 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, 54.4 % of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of (4-(4-aminophenyl)(4-iminocyclohexa-2,5-dienylidene)methyl)-2-methylaniline hydrochloride in soil is estimated to be 120 days ( 2880 hrs). Based on this half-life value of (4-(4-aminophenyl)(4-iminocyclohexa-2,5-dienylidene)methyl)-2-methylaniline hydrochloride, it is concluded that the chemical is not persistent in the soil environment and the exposure risk to soil dwelling animals is moderate to low.

Additional information

Biodegradation in water:

Various predicted data for the target compound (4-(4-aminophenyl)(4-imino -cyclohexa-2,5-dienylidene) methyl)-2-methylaniline hydrochloride (CAS No. 632-99-5) 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 first experimental study from J-check databases 2017 for the target chemical (4-(4-aminophenyl)(4-imino -cyclohexa-2,5-dienylidene) methyl)-2-methylaniline hydrochloride, biodegradation experiment was conducted for evaluating the percentage biodegradability. Biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of test substance (4-(4-aminophenyl)(4-imino -cyclohexa-2,5-dienylidene) methyl)-2-methylaniline hydrochloride. (CAS no. 632-99-5). 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 test substance was determined to 0, 13 and 2% by BOD, TOC, and HPLC parameter in 28 days. Thus, based on percentage degradation, (4-(4-aminophenyl)(4-imino -cyclohexa-2,5-dienylidene) methyl)-2-methylaniline hydrochloride is considered to be not readily biodegradable in water.

 

In second prediction using the Estimation Programs Interface Suite (EPI suite, 2017) the biodegradation potential of the test compound (4-(4-aminophenyl) (4-iminocyclohexa-2, 5-dienylidene)methyl) -2-methylaniline hydrochloride (632 -99 -5) in the presence of mixed populations of environmental microorganisms. 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 chemical (4-(4-aminophenyl)(4-iminocyclohexa-2,5-dienylidene)methyl)-2-methylaniline hydrochloride is expected to be not readily biodegradable.

 

In a supporting weight of evidence study from peer reviewed journal (Toshihide Saito et. al, 1984) for the read across chemical 4,4'-carbonimidoylb is (N,N-dimethylaniline) hydrochloride (CAS no. 2465-27-2),biodegradation experiment was conducted for evaluating the percentage biodegradability of read across substance 4,4'-carbonimidoylbis (N,N-dimethylaniline) hydrochloride. 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 read across chemical was determined to be 0.038, 1.42, 2.50 and 0.32 g/g, respectively. The BOD5/TOC ratio of read across 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 chemical 4,4'-carbonimidoylbis(N,N-dimethylaniline) hydrochloride is not readily biodegradable in nature.

 

For the same read across chemical 4,4'-carbonimidoylbis(N,N-dimethylaniline) hydrochloride (CAS no. 2465-27-2), biodegradation study was conducted for 14 days for evaluating the percentage biodegradability of read across substance 4,4'-carbonimidoylbis(N,N-dimethylaniline) hydrochloride. (CAS no. 2465-27-2) (J-CHECK, 2017 and EnviChem, 2014). 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 4,4'-carbonimidoylbis(N,N-dimethylaniline) hydrochloride was determined to 0 and 12% by BOD and UV-Vis parameter in 14 days. Thus, based on percentage degradation, 4,4'-carbonimidoylbis(N,N-dimethylaniline) hydrochloride is considered to be not readily biodegradable in nature.

 

Similarly another biodegradation study (from authoritative database J-CHECK, 2017) was conducted for 28 days for evaluating the percentage biodegradability of read across substance 4-[4-(dimethylamino) benzene carboximidoyl]-N,N-dimethylaniline hydrochloride (1100-88-5). The test chemical was subjected to biodegradation test by taking sludge as inoculums at 30 mg/L concentration. Biodegradation was analyzed by using O2 consumption (BOD), TOC removal and test material analysis by HPLC. The initial concentration of test chemical was 100 mg/L and by taking standard test equipment. After 4 weeks (28 days) test chemical benzyl(triphenyl) phosphanium chloride showed 0% biodegradation by all three parameters namely O2 consumption (BOD) parameter, TOC removal and test material analysis by HPLC parameter in 28 days. So it is concluded that this test Chemical is not readily biodegradable.

 

On the basis of above results for target chemical (4-(4-aminophenyl)(4-imino -cyclohexa-2,5-dienylidene) methyl)-2-methylaniline hydrochloride (CAS No. 632-99-5) from J- check, EPI suite, 2017 and for its read across substance (from peer reviewed journal, authoritative database J-CHECK, EnviChem, it can be concluded that the test substance (4-(4-aminophenyl)(4-imino -cyclohexa-2,5-dienylidene) methyl)-2-methylaniline hydrochloride 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 (4-(4-aminophenyl) (4-iminocyclohexa-2, 5- dienylidene)methyl)-2-methylaniline hydrochloride (CAS No. 632 -99 -5). If released in to the environment, 3.02 % of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of (4-(4-aminophenyl)(4-iminocyclohexa-2,5-dienylidene)methyl) -2-methylaniline hydrochloride 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 moderate to high whereas the half-life period of (4-(4-aminophenyl) (4-iminocyclohexa-2,5-dienylidene)methyl)-2- methylaniline hydrochloride in sediment is estimated to be 541.66 days (13000 hrs). Based on this half-life value, it indicates that (4-(4-aminophenyl)(4-iminocyclohexa-2,5- dienylidene)methyl)-2-methylaniline hydrochloride is persistent in sediment.

Biodegradation in soil:

The half-life period of (4-(4-aminophenyl)(4-iminocyclohexa-2,5-dienylidene)methyl)-2-methylaniline hydrochloride (632 -99 -5) 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, 54.4 % of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of (4-(4-aminophenyl)(4-iminocyclohexa-2,5-dienylidene)methyl)-2-methylaniline hydrochloride in soil is estimated to be 120 days ( 2880 hrs). Based on this half-life value of (4-(4-aminophenyl)(4-iminocyclohexa-2,5-dienylidene)methyl)-2-methylaniline hydrochloride, it is concluded that the chemical is not persistent in the soil environment and the exposure risk to soil dwelling animals is moderate to low.