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Description of key information

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.

Bioaccumulation: aquatic / sediment:

BCFBAF model (v3.01) of Estimation Programs Interface (EPI Suite, 2017) was used to predict the bioconcentration factor (BCF) of test chemical (4-(4-aminophenyl) (4-iminocyclohexa-2,5- dienylidene)methyl)-2-methylaniline hydrochloride (632 -99 -5). The bioconcentration factor (BCF) of (4-(4-aminophenyl)(4-iminocyclohexa -2,5-dienylidene)methyl) -2-methylaniline hydrochloride was estimated to be 3.162 L/kg whole body w.w (at 25 deg C) which not exceed the bio concentration threshold of 2000, indicating that the chemical (4-(4-aminophenyl)(4-iminocyclohexa-2,5- dienylidene)methyl)-2-methylaniline hydrochloride is expected to non bioaccumulate in the food chain.

Adsorption / desorption

The adsorption coefficient Koc in soil and in sewage sludge of test chemical (4-(4-aminophenyl)(4-iminocyclohexa-2,5-dienylidene)methyl)-2-methylaniline hydrochloride (CAS No. 632 -99 -5) was determined by the Reverse Phase High Performance Liquid Chromatographic method according to OECD Guideline No. 121 for testing of Chemicals (Experimental study report, 2018). The solutions of the test substance and reference substances were prepared in appropriate solvents. A test item solution was prepared by accurately weighing 4 mg of test item and diluted with Methanol up to 10 ml. Thus, the test solution concentration was 400 mg/l. The pH of test substance was 6.3. Each of the reference substance and test substance were analysed by HPLC at 210 nm. After equilibration of the HPLC system, Urea was injected first, the reference substances were injected in duplicate, followed by the test chemical solution in duplicate. Reference substances were injected again after test sample, no change in retention time of reference substances was observed. Retention time tR were measured, averaged and the decimal logarithms of the capacity factors k were calculated. The graph was plotted between log Koc versus log k(Annex - 2).The linear regression parameter of the relationship log Koc vs log k were also calculated from the data obtained with calibration samples and therewith, log Koc of the test substance was determined from its measured capacity factor. The reference substances were chosen according to functional similarity with the test substance and calibration graph prepared. The reference substances were Benzamide, N-methylbenzamide, 4-Nitrobenzamide, N,N-dimethylbenzamide, 4 -methylaniline (p-Tolouidine), 4 -chloroaniline, Nitrobenzene, 2 - nitrophenol having Koc value ranging from 1.239 to 2.47. The Log Koc value of test chemical (4 -(4 -aminophenyl)(4 -iminocyclohexa-2,5 -dienylidene)methyl)-2 -methylaniline hydrochloride was determined to be 1.908 ± 0.009 at 25°C. This log Koc value indicates that the substance (4 -(4 -aminophenyl)(4 -iminocyclohexa-2,5 -dienylidene)methyl)-2 -methylaniline hydrochloride has a low sorption to soil and sediment and therefore have moderate migration potential to ground water.

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 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.

Bioaccumulation: aquatic / sediment:

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 study for its read across substance were reviewed for the bioaccumulation end point which are summarized as below:

 

In a prediction done using BCFBAF model (v3.01) of Estimation Programs Interface (EPI Suite, 2017) was used to predict the bioconcentration factor (BCF) of test chemical (4-(4-aminophenyl) (4-iminocyclohexa-2,5- dienylidene)methyl)-2-methylaniline hydrochloride (632 -99 -5). The bioconcentration factor (BCF) of (4-(4-aminophenyl)(4-iminocyclohexa -2,5-dienylidene)methyl) -2-methylaniline hydrochloride was estimated to be 3.162 L/kg whole body w.w (at 25 deg C) which not exceed the bio concentration threshold of 2000, indicating that the chemical (4-(4-aminophenyl)(4-iminocyclohexa-2,5- dienylidene)methyl)-2-methylaniline hydrochloride is expected to non bioaccumulate in the food chain.

 

In a second predicted report, Using Bio-concentration Factor (v12.1.0.50374) module Bio-concentration Factor over the pH scale 6, 7, 8 of the test substance (4-(4-aminophenyl)(4-iminocyclohexa- 2,5-dienylidene) methyl) -2-methylaniline hydrochloride (632 -99 -5) estimated to be 1, 1.52, 2.52 respectively. This value indicates that the test substance (4-(4-aminophenyl)(4-iminocyclohexa-2,5-dienylidene) methyl) -2-methylaniline hydrochloride was non-accumulative in aquatic organisms.

 

From CompTox Chemistry Dashboard using OPERA (OPEn (quantitative) structure-activity Relationship Application)  V1.02 model in which calculation based on PaDEL descriptors (calculate molecular descriptors and fingerprints of chemical)  the bioaccumulation i.e BCF for test substance (4-(4-aminophenyl) (4-iminocyclohexa-2,5- dienylidene) methyl)-2-methylaniline hydrochloride was estimated to be 21.8 dimensionless . The predicted BCF result based on the 5 OECD principles. Thus based on the result it is concluded that the test substance (4-(4-aminophenyl)(4-iminocyclohexa-2,5- dienylidene) methyl)-2-methylaniline hydrochloride is non- bioaccumulative in nature.

 

Similarly in a supporting weight of evidence study from authoritative database J-CHECK, 2017 for the read across chemical 4-[4-(dimethylamino) benzene- carboximidoyl]-N,N- dimethylaniline hydrochloride, Bioaccumulation test was conducted for 6 weeks for determination the bioconcentration factor (BCF) of substance 4-[4-(dimethylamino)benzenecarboximidoyl]-N,N- dimethylaniline hydrochloride (CAS no 2465-27-2) on test organism Cyprinus carpio. Recovery ratio : Test water : 1st concentration area : 90.2 % , 2nd concentration area : 90.0% Fish : 54.0%, ­ Limit of detection :  Fish : 0.012 microg/g And Nominal concentrations used in the study as - 1st Concentration area: 0.1 mg/L, 2nd Concentration area : 0.01 mg/L and Range finding study was carried out on Rice fish (Oryzias latipes) TLm(48h) 5 .3 ppm(w/v). Thus according to static Fish Test the BCF value for test substance4-[4-(dimethylamino) benzene-carboximidoyl] -N,N-dimethylaniline hydrochloride was observed to be 3.8-11 L/kg at dose concentration 0.1 ppm(w/v) and 6.1-16 L/kg at dose concentration 0.01 ppm(w/v) on test organism Cyprinus carpio during 6 weeks period. These BCF values indicate that the substance 4-[4 -(dimethylamino) benzenecarboximidoyl]-N,N-dimethylaniline hydrochloride is not bioaccumulative in fish and food chain.

 

For the read across chemical (569-64-2) HSDB, 2017, The BCF value of chemical 4-[(4-dimethyl-aminophenyl)-phenylmethylidene]cyclohexa-2,5-dien-1-ylidene]- dimethylazanium chloride (CAS no. 569-64-2) was estimated is 3 dimensionless by using log Kow of 0.62 and regression derived equation and it is far less than 2000 so it is concluded that this chemical is non bioaccumulative.

 

On the basis of above results for target chemical (4-(4-aminophenyl)(4-imino -cyclohexa-2,5-dienylidene) methyl)-2-methylaniline hydrochloride (from EPI suite, ACD labs and CompTox Chemistry Dashboard,  2017) and for its read across substance (from authoritative database J-CHECK and HSDB, 2017), it can be concluded that the BCF value of test substance (4-(4-aminophenyl)(4-imino -cyclohexa-2,5-dienylidene) methyl)-2-methylaniline hydrochloride ranges from 0.62-21.8 which does not exceed the bioconcentration threshold of 2000, indicating that the chemical (4-(4-aminophenyl)(4-imino -cyclohexa-2,5-dienylidene) methyl)-2-methylaniline hydrochloride is not expected to bioaccumulate in the food chain. 

Adsorption / desorption

The adsorption coefficient Koc in soil and in sewage sludge of test chemical (4-(4-aminophenyl)(4-iminocyclohexa-2,5-dienylidene)methyl)-2-methylaniline hydrochloride (CAS No. 632 -99 -5) was determined by the Reverse Phase High Performance Liquid Chromatographic method according to OECD Guideline No. 121 for testing of Chemicals (Experimental study report, 2018). The solutions of the test substance and reference substances were prepared in appropriate solvents. A test item solution was prepared by accurately weighing 4 mg of test item and diluted with Methanol up to 10 ml. Thus, the test solution concentration was 400 mg/l. The pH of test substance was 6.3. Each of the reference substance and test substance were analysed by HPLC at 210 nm. After equilibration of the HPLC system, Urea was injected first, the reference substances were injected in duplicate, followed by the test chemical solution in duplicate. Reference substances were injected again after test sample, no change in retention time of reference substances was observed. Retention time tR were measured, averaged and the decimal logarithms of the capacity factors k were calculated. The graph was plotted between log Koc versus log k(Annex - 2).The linear regression parameter of the relationship log Koc vs log k were also calculated from the data obtained with calibration samples and therewith, log Koc of the test substance was determined from its measured capacity factor. The reference substances were chosen according to functional similarity with the test substance and calibration graph prepared. The reference substances were Benzamide, N-methylbenzamide, 4-Nitrobenzamide, N,N-dimethylbenzamide, 4 -methylaniline (p-Tolouidine), 4 -chloroaniline, Nitrobenzene, 2 - nitrophenol having Koc value ranging from 1.239 to 2.47. The Log Koc value of test chemical (4 -(4 -aminophenyl)(4 -iminocyclohexa-2,5 -dienylidene)methyl)-2 -methylaniline hydrochloride was determined to be 1.908 ± 0.009 at 25°C. This log Koc value indicates that the substance (4 -(4 -aminophenyl)(4 -iminocyclohexa-2,5 -dienylidene)methyl)-2 -methylaniline hydrochloride has a low sorption to soil and sediment and therefore have moderate migration potential to ground water.