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Description of key information

Hydrolysis:

The study does not need to be conducted because the substance is readily biodegradable.

Biodegradation in water:

Biodegradation study was conducted for evaluating the percentage biodegradability of test chemical. Although % degradation of test chemical was not known, but chemical was reported to be degraded by Nocardia sp. in wastewaters. Thus, on the basis of the results reported, test chemical was considered to be biodegradable in nature.

Biodegradation in water and sediment:

In accordance with column 2 of Annex IX of the REACH regulation, testing for this end point is scientifically not necessary and does not need to be conducted since the test chemical is readily biodegradable in water.

Biodegradation in soil:

In accordance with column 2 of Annex IX of the REACH regulation, testing for this end point is scientifically not necessary and does not need to be conducted since the test chemical is readily biodegradable in water.

Bioaccumulation: aquatic / sediment:

In a prediction done using the 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 70.794 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. The solutions of the test substance and reference substances were prepared in appropriate solvents. A test item solution was prepared by accurately measuring 4μL of test item and diluted with acetonitrile up to 10 ml. Thus, the test solution concentration was 392 mg/l. The pH of test substance was 8.00. 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. The linear regression parameter of the relationship log Koc vs log k were also calculated from the data obtained with calibration samples and there with, 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 were chosen according to estimated Koc range of the test substance and generalized calibration graph was prepared. The reference substances were having Koc value ranging from 1.25 to 4.09. The Log Koc value of test chemical was determined to be 3.104 ± 0.002 at 25°C. This log Koc value indicates that the test chemical has a moderate sorption to soil and sediment and therefore have slow migration potential to ground water.

Additional information

Hydrolysis:

The study does not need to be conducted because the substance is readily biodegradable.

Biodegradation in water:

Summarized result for the determination of biodegradation rate of test chemical and structurally and functionally similar read across chemicals were reviewed and mention as below:

Biodegradation study was conducted for evaluating the percentage biodegradability of test chemical. Although % degradation of test chemical was not known, but chemical was reported to be degraded by Nocardia sp. in wastewaters. Thus, on the basis of the results reported, test chemical was considered to be biodegradable in nature.

Above study further supported by the second weight of evidence study from experimental report. 28-days Manometric respirometry test was conducted following the OECD guideline 301F to determine the ready biodegradability of the test chemical. The study was performed at a temperature of 20± 1°C. Mixture of domestic waste water, surface soil and soil samples was used as a test inoculum for the study. This inoculum was collected and were mixed to get diluted suspension. The inoculum was kept aerobic until being used for experiment by supplying organic and inorganic sources required by micro flora to sustain at controlled laboratory conditions.  This gave the bacterial count as 107to 108 CFU/ml. At the regular interval microbial plating was also performed on agar to confirm the vitality and CFU count of microorganism. OECD mineral medium was used for the study. The test system included control, test item and reference item. The concentration of test and reference item ( Sodium Benzoate) chosen for both the study was 30 mg/L, while that of inoculum was 25 ml/l. 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 (Sodium Benzoate) was also calculated using BOD & ThOD and was determined to be 70.27%. The mean BOD values (mg O2/l) in control on 28th day was 16.31 mg O2/l, thereby fulfilling the control validity criteria (i.e., the oxygen consumption of the inoculum blank is normally 20-30 mg O2/l and should not be greater than 60 mg/l in 28 days). Degradation of Sodium Benzoate exceeds 56.056 %after 7 days and 61.461 % after 14 days. The activity of the inoculums is thus verified and the test can be considered as valid. The BOD28 value of test chemical was observed to be 2.013 mgO2sup>/mg. ThOD was calculated as 2.262 mgO2/mg. Accordingly, the % degradation of the test item after 28 days of incubation at 20 ± 1°C according to manometric respirometry test was determined to be 89.007 %. Based on the results, the test chemical, under the test conditions, was considered to be readily biodegradable at 20 ± 1°C over a period of 28 days.

Similar 14-days Closed Bottle test was conducted 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 chemical and reference item. Polyseed were used for this study. 1 polyseed capsule were added in 500 ml D.I water and then stirred for 1 hour for proper mixing and functioning of inoculum. This gave the bacterial count as 10E7 to 10E8 CFU/ml. At the regular interval microbial plating was also performed on agar to confirm the vitality and CFU count of microorganism. The concentration of test and reference chemical (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 chemical and reference chemical. The % degradation of procedure control (reference item) was also calculated using BOD & ThOD and was determined to be 75.3 % at 20 ± 1°C. Degradation of Sodium Benzoate exceeds 64.46% on 7 days & 75.30% on 14th day. The activity of the inoculum was thus verified and the test can be considered as valid.The BOD14 value of test chemical was observed to be 1.47 mgO2/mg. ThOD was calculated as 2.31 mgO2/mg. Accordingly, the % degradation of the test chemical after 14 days of incubation at 20 ± 1°C according to Closed Bottle test was determined to be 63.63 %. Based on the results, the test chemical was considered to be readily biodegradable in water.

Thus, based on the above all studies and rate of degradation observations, chemical was considered to be readily biodegradable in nature.

Biodegradation in water and sediment:

In accordance with column 2 of Annex IX of the REACH regulation, testing for this end point is scientifically not necessary and does not need to be conducted since the test chemical is readily biodegradable in water.

Biodegradation in soil:

In accordance with column 2 of Annex IX of the REACH regulation, testing for this end point is scientifically not necessary and does not need to be conducted since the test chemical is readily biodegradable in water.

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 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 70.794 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.

 

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 chemical was estimated to be 1410 dimensionless . The predicted BCF result based on the 5 OECD principles.

 

On the basis of above results for test chemical, it can be concluded that the BCF value of test chemical was ranges from 70.794 L/kg to1410 dimensionless,which does not exceed the bioconcentration 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. The solutions of the test substance and reference substances were prepared in appropriate solvents. A test item solution was prepared by accurately measuring 4μL of test item and diluted with acetonitrile up to 10 ml. Thus, the test solution concentration was 392 mg/l. The pH of test substance was 8.00. 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. The linear regression parameter of the relationship log Koc vs log k were also calculated from the data obtained with calibration samples and there with, 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 were chosen according to estimated Koc range of the test substance and generalized calibration graph was prepared. The reference substances were having Koc value ranging from 1.25 to 4.09. The Log Koc value of test chemical was determined to be 3.104 ± 0.002 at 25°C. This log Koc value indicates that the test chemical has a moderate sorption to soil and sediment and therefore have slow migration potential to ground water.