Dihydrogen (ethyl)[4-[[4-[ethyl(3-sulphonatobenzyl)amino]phenyl](2-sulphonatophenyl)methylene]cyclohexa-2,5-dien-1-ylidene](3-sulphonatobenzyl)ammonium, aluminium salt

Endpoint summary

Description of key information

Hydrolysis

On the basis of the experimental studies of the structurally and functionally similar read across chemical and applying the weight of evidence approach, the hydrolysis half-life value of the test chemical can be expected to be > 5 days at pH 4, 7 and 9 & at a temperature of 50⁰C, respectively or > 1 years at pH 7 & at a temperature of 20⁰C, respectively.

Biodegradation in water

Biodegradation study was conducted for 42-days using Closed Bottle test following the OECD guideline 301 D to determine the ready biodegradability of the test chemical (Experimental study report, 2019). The study was performed at a temperature of 20°C. The test system included control, test chemical and reference substance. Polyseed were used for this study. The concentration of test and reference substance (Sodium Benzoate) chosen for both the study was 4 mg/L, while that of inoculum was 1 ml/l. OECD mineral medium was used for the study. ThOD (Theoretical oxygen demand) of test and reference chemical was determined by calculation. % degradation was calculated using the values of BOD and ThOD for test chemical and reference substance. The % degradation of procedure control (reference item) was also calculated using BOD & ThOD and was determined to be 85.54%. Degradation of Sodium Benzoate exceeds 70.48% on 7 days & 76.5% on 14th day. The activity of the inoculum is thus verified and the test can be considered as valid. The BOD42 value of test chemical was observed to be 0.87 mgO2/mg. ThOD was calculated as 1.83 mgO2/mg. Accordingly, the % degradation of the test item after 42 days of incubation at 20 ± 1°C according to Closed Bottle test was determined to be 47.54%. Based on the results, the test item, under the test conditions, was considered to be inherently biodegradable in nature.

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 3.162 L/kg whole body w.w (at 25°C) which does not exceed the bio concentration threshold of 2000, indicating that the test chemical is not expected to 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 (Experimental study report, 2017). The solutions of the test substance and reference substances were prepared in appropriate solvents. A test item solution was prepared by accurately weighing 3 mg of test item and diluted with acetonitrile:water (9:1) up to 10ml. Thus, the test solution concentration was 300 mg/l. The pH of test substance was 2.48. 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 group similarity with the test substance and calibration graph was prepared. The reference substances were 4-methylaniline(p-Tolouidine), Nmethylaniline, aniline, xylene, ethylbenzene, toluene and naphthalene having Koc value ranging from 1.9 to 2.75. The Log Koc value of test chemical was determined to be 2.0917 ± 0.0002 dimensionless at 25°C.This log Koc value indicates that the substance has a low sorption to soil and sediment and therefore have moderate migration potential to ground water.

Additional information

Hydrolysis

Data available for the structurally and functionally similar read across chemicals has been reviewed to determine the half-life of the test chemical.The studies are as mentioned below:

The half-life of the test chemical was determined at different pH range. The study was performed according to OECD Guideline 111 (Hydrolysis as a Function of pH) at a temperature of 50°C. The average percentage recovery of the test chemical after 5 days was determined to be 99.0, 99.5 and 98.7% at pH 4, 7 and 9, respectively. As no hydrolysis of test item was observed for a period of 5 days, the half-lives was determined to be > 5 days at pH 4, 7 and 9 & at a temperature of 50⁰C, respectively. Based on the half-life values, it is concluded that the test substance was considered to be stable in water.

In an another study, the half-life of the test chemical was determined at pH 7.0. The study was performed at a temperature of 50°C. The only functional group present is the amide group, which hydrolyzes slowly at neutral pH. The half-life value of the test chemical was determined to be > 1 years at pH 7 & at a temperature of 20⁰C, respectively. Based on the half-life value, it is concluded that test chemical was considered to be hydrolytically stable.

On the basis of the experimental studies of the structurally and functionally similar read across chemical and applying the weight of evidence approach, the hydrolysis half-life value of the test chemical can be expected to be  > 5 days at pH 4, 7 and 9 & at a temperature of 50⁰C, respectively or  > 1 years at pH 7 & at a temperature of 20⁰C, respectively.

Biodegradation in water

Biodegradation study was conducted for 42-days using Closed Bottle test following the OECD guideline 301 D to determine the ready biodegradability of the test chemical (Experimental study report, 2019). The study was performed at a temperature of 20°C. The test system included control, test chemical and reference substance. Polyseed were used for this study. The concentration of test and reference substance (Sodium Benzoate) chosen for both the study was 4 mg/L, while that of inoculum was 1 ml/l. OECD mineral medium was used for the study. ThOD (Theoretical oxygen demand) of test and reference chemical was determined by calculation. % degradation was calculated using the values of BOD and ThOD for test chemical and reference substance. The % degradation of procedure control (reference item) was also calculated using BOD & ThOD and was determined to be 85.54%. Degradation of Sodium Benzoate exceeds 70.48% on 7 days & 76.5% on 14th day. The activity of the inoculum is thus verified and the test can be considered as valid. The BOD42 value of test chemical was observed to be 0.87 mgO2/mg. ThOD was calculated as 1.83 mgO2/mg. Accordingly, the % degradation of the test item after 42 days of incubation at 20 ± 1°C according to Closed Bottle test was determined to be 47.54%. Based on the results, the test item, under the test conditions, was considered to be inherently biodegradable in nature.

Bioaccumulation: aquatic / sediment

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

 

In aprediction done using theBCFBAF Programof 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 3.162 L/kg whole body w.w (at 25°C).

 

In a supporting weight of evidence study from authoritative database (2017) for the test chemical,he bioaccumulation study was conducted for estimating the BCF (bioaccumulation factor) value of test chemical. The bioaccumulation factor (BCF) value was calculated using a logKow of -2.74 and a regression-derived equation. The estimated BCF (bioaccumulation factor) value of test chemical was determined to be 3.0 dimensionless.

 

For the test chemical, the bioaccumulation study was conducted for determining the BCF (bioaccumulation factor) value of test chemical (HSDB, 2017). Although BCF value of test chemical was not known, but ionic character of test chemical indicates that the chemical is non-bioaccumulative in aquatic organisms.

 

On the basis of above results of the test chemical, it can be concluded that the BCF value of test chemical was evaluated to be 3.0,which does not exceed the bioconcentration threshold of 2000, indicating that the test chemicalis not expected to 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 (Experimental study report, 2017). The solutions of the test substance and reference substances were prepared in appropriate solvents. A test item solution was prepared by accurately weighing 3 mg of test item and diluted with acetonitrile:water (9:1) up to 10ml. Thus, the test solution concentration was 300 mg/l. The pH of test substance was 2.48. 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 group similarity with the test substance and calibration graph was prepared. The reference substances were 4-methylaniline(p-Tolouidine), Nmethylaniline, aniline, xylene, ethylbenzene, toluene and naphthalene having Koc value ranging from 1.9 to 2.75. The Log Koc value of test chemical was determined to be 2.0917 ± 0.0002 dimensionless at 25°C.This log Koc value indicates that the substance has a low sorption to soil and sediment and therefore have moderate migration potential to ground water.