α,α-bis[4-(dimethylamino)phenyl]-4-(phenylamino)naphthalene-1-methanol

Endpoint summary

Description of key information

Hydrolysis

In accordance with column 2 of Annex VIII of the REACH regulation, testing for this endpoint is technically not feasible and does not need to be conducted since the test chemical is insoluble in water.

Biodegradation in water

Estimation Programs Interface Suite (2018) was run to predict the biodegradation potential of the test chemical 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 test chemical is expected to be not readily biodegradable.

Bioaccumulation: aquatic / sediment

BCFBAF model of Estimation Programs Interface was used to predict the bioconcentration factor (BCF) of test chemical. The bioconcentration factor (BCF) of test chemical was estimated to be 10500 L/kg whole body w.w (at 25 deg C) which does exceeds the bio concentration threshold of 5000, indicating that the test chemical is expected to be very bioaccumulate in the food chain.

Adsorption / desorption

The adsorption coefficient Koc in soil and in sewage sludge of test chemical was determined by the Reverse Phase High Performance Liquid Chromatographic method according to OECD Guideline No. 121 for testing of Chemicals. A test item solution was prepared by accurately weighing 20 mg of test item and diluted with ACN up to 10 ml. Thus, the test solution concentration was 2000 mg/l. The sample was sonicated for 2 minutes and filtered through a 0.22 µm syringe filter. The pH of the sample was found to be 7.9. Each of the reference substance and test substance were analysed by HPLC at 210 nm. For the HPLC method, HPLC model no. Agilent Technologies,1260 Infinity II was used. Column used was Waters sperisorb, 4.6*250 mm, 5µ (CL-25). Acetonitrile : water (55:45) was used as a mobile phase. During the study, flow rate was 1.0ml/min. Study was performed at a temperature of 25°C. Injector volume was 10μl. Chem Station Open lab Control Panel was used as a data Acquisition software and detector wavelength taken for the study was 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'. 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 estimated Koc range of the test substance and generalized calibration graph was prepared. The reference substances Aniline, 4-Chloroaniline, 2,5-Dichloroaniline, Naphthalene, Biphenyl, Phenanthrene, Triphenylamine and DDT were chosen having log Koc range from 1.8 to 5.4. The Log Koc value of test chemical was determined to be 6.475±0.010 at 25°C.This log Koc value indicates that the test chemical has a very strong sorption to soil and sediment and therefore have negligible migration potential to ground water.

Additional information

Hydrolysis

In accordance with column 2 of Annex VIII of the REACH regulation, testing for this endpoint is technically not feasible and does not need to be conducted since the test chemical is insoluble in water.

Biodegradation in water

Predicted data of the test chemical and various supporting studies for its structurally similar read across substance were reviewed for the biodegradation end point which are summarized as below:

 

In a prediction using the Estimation Programs Interface Suite (2018), the biodegradation potential of the test chemical in the presence of mixed populations of environmental microorganisms was estimated. 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 test chemical is expected to be not readily biodegradable.

 

In a supporting weight of evidence study from study report (2018) for the test item,28-days Closed Bottle test following the OECD guideline 301 D to determine the ready biodegradability of the test chemical. The study was performed at a temperature of 20°C. The test system included control, test item and reference item. Polyseed were used for this study. The concentration of test and reference item (Sodium Benzoate) chosen for both the study was 4 mg/L, while that of inoculum was 32 ml/l. OECD mineral medium was used for the study. ThOD (Theoretical oxygen demand) of test and reference item was determined by calculation. % degradation was calculated using the values of BOD and ThOD for test item and reference item. The % degradation of procedure control (reference item) was also calculated using BOD & ThOD and was determined to be 72.28%. Degradation of Sodium benzoate exceeds 63.25 % on 7 days & 69.27 % on 14th day. The activity of the inoculum was thus verified and the test can be considered as valid. The BOD28 value of test chemical was observed to be 0.4 mgO2/mg. ThOD was calculated as 1.31 mgO2/mg. Accordingly, the % degradation of the test item after 28 days of incubation at 20 ± 1°C according to Closed Bottle test was determined to be 30.53%. Based on the results, the test item, under the test conditions, was considered to be not readily biodegradable in nature.

 

For the test chemical,28-days Closed Bottle test following the OECD guideline 301 D to determine the ready biodegradability of the test chemical (Experimental study report, 2018). The study was performed at a temperature of 20°C. The test system included control, test item and reference item. Polyseed were used for this study.The concentration of test and reference item (Sodium Benzoate) chosen for both the study was 4 mg/L, while that of inoculum was 32 ml/l. OECD mineral medium was used for the study. ThOD (Theoretical oxygen demand) of test and reference item was determined by calculation. % degradation was calculated using the values of BOD and ThOD for test item and reference item. The % degradation of procedure control (reference item) was also calculated using BOD & ThOD and was determined to be 73.49%. Degradation of Sodium Benzoate exceeds 31.32% on 7 days & 49.39% on 14th day. The activity of the inoculum was thus verified and the test can be considered as valid. The BOD28 value of test chemical was observed to be 0.52 mgO2/mg. ThOD was calculated as 2.44 mgO2/mg. Accordingly, the % degradation of the test item after 28 days of incubation at 20 ± 1°C according to Closed Bottle test was determined to bee 21.31%. Based on the results, the test item, under the test conditions, was considered to be not readily biodegradable in nature.

 

On the basis of above results for test chemical, it can be concluded that the test chemical can be expected to be not readily biodegradable in nature.

Bioaccumulation: aquatic / sediment

Various predicted data of the test chemical were reviewed for the bioaccumulation end point which are summarized as below:

 

In a prediction done using the BCFBAF Program of Estimation Programs Interface was used to predict the bioconcentration factor (BCF) of test chemical. The bioconcentration factor (BCF) of test chemical was estimated to be 10500 L/kg whole body w.w (at 25 deg C).

 

In an another prediction done by using the SciFinder database (American Chemical Society (ACS), 2017), the bioconcentration factor (BCF) of test chemical was estimated to be 62.2, 92.2, 178, 3470, 60900, 219000, 282000, 290000 and 291000 at pH range 1, 2, 3, 4, 5, 6, 7, 8 and 9-10, respectively (at 25 deg C).

 

On the basis of above results for test chemical(from modelling databases,2017), it can be concluded that the BCF value of test chemical was evaluated to be ranges from 10500 to 291000, respectively,which exceeds the bioconcentration threshold of 5000, indicating that the test chemical is expected to be very bioaccumulate in the food chain.

Adsorption / desorption

The adsorption coefficient Koc in soil and in sewage sludge of test chemical was determined by the Reverse Phase High Performance Liquid Chromatographic method according to OECD Guideline No. 121 for testing of Chemicals. A test item solution was prepared by accurately weighing 20 mg of test item and diluted with ACN up to 10 ml. Thus, the test solution concentration was 2000 mg/l. The sample was sonicated for 2 minutes and filtered through a 0.22 µm syringe filter. The pH of the sample was found to be 7.9. Each of the reference substance and test substance were analysed by HPLC at 210 nm. For the HPLC method, HPLC model no. Agilent Technologies,1260 Infinity II was used. Column used was Waters sperisorb, 4.6*250 mm, 5µ (CL-25). Acetonitrile : water (55:45) was used as a mobile phase. During the study, flow rate was 1.0ml/min. Study was performed at a temperature of 25°C. Injector volume was 10μl. Chem Station Open lab Control Panel was used as a data Acquisition software and detector wavelength taken for the study was 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'. 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 estimated Koc range of the test substance and generalized calibration graph was prepared. The reference substances Aniline, 4-Chloroaniline, 2,5-Dichloroaniline, Naphthalene, Biphenyl, Phenanthrene, Triphenylamine and DDT were chosen having log Koc range from 1.8 to 5.4. The Log Koc value of test chemical was determined to be 6.475±0.010 at 25°C.This log Koc value indicates that the test chemical has a very strong sorption to soil and sediment and therefore have negligible migration potential to ground water.