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Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Stability:

Hydrolysis:

On the basis of the experimental studies of the test chemical and applying the weight of evidence approach, the hydrolysis half-life value of the test chemical can be expected to be ranges 7.3  yr, at pH range 7 and 270 days at pH 8 by base catalysed second order hydrolysis rate constant. Thus, based on this half-life value, it can be concluded that the test chemical not hydrolysable in water.

Biodegradation:

Biodegradation in water:

28-days Closed Bottle test following the OECD guideline 301 D was performed to determine the ready biodegradability of the test item. The study was performed at a temperature of 20°C. The test system included control, test item and reference item. Polyseed were used as inoculum with bacterial count as 10E7 to 10E8 CFU/ml.The concentration of test and reference item (Sodium Benzoate) chosen for both the study was 4 mg/L, while that of inoculum was 32ml/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 39.15 % on 7 days & 61.44 on 14th day. The activity of the inoculum is thus verified and the test can be considered as valid. The BOD28 value of test chemical was observed to be 0.42 mgO2/mg. ThOD was calculated as 3.04 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 13.81 %. Based on the results, the test item, under the test conditions, was considered to be not readily biodegradable in nature.

Biodegradation in water and sediments:

Estimation Programs Interface (EPI Suite, 2018) prediction model was run to predict the half-life in water and sediment for the test chemical. If released in to the environment, 17.1 % of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of test chemical in water is estimated to be 37.5  days (900 hrs). The half-life (37.5  days estimated by EPI suite) indicates that the chemical is not persistent in water and the exposure risk to aquatic animals is low , whereas the half-life period of test chemical in sediment is estimated to be  337.5 days (8100 hrs). However, as the percentage release of test chemical into the sediment is less than 3 % (i.e, reported as  2.71 %), indicates that test chemical is not persistent in sediment.

Biodegradation in soil:

The half-life period of test chemical in soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database (EPI suite, 2018). If released into the environment, 79.9 % of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of test chemical in soil is estimated to be 75 days (1800 hrs). Based on this half-life value of test chemical, it is concluded that the chemical is not persistent in the soil environment and the exposure risk to soil dwelling animals is low .

Bioaccumulation:

Bioaccumulation: aquatic/sediments:

Using BCFBAF Program (v3.00) model of EPI suite (2018) the estimated bio concentration factor (BCF) for test chemical is 1985 L/kg wet-wt at 25 deg. c which does not exceed the bioconcentration threshold of 2000, but very close to the value. Therefore it is concluded that test chemical is bioaccumulative in food chain.

Transport and distribution:

Adsorption Coefficient:

The Adsorption Coefficient of test substance  was determined as per the HPLC method (OECD Guideline-121). The Log Koc value was determined to be  2.321 dimensionless at 25°C. Thus based on the result it is concluded that the test substance has a low sorption to soil and sediment and therefore has moderate migration potential to ground water.

Additional information

Stability:

Hydrolysis:

Data available for the test chemical has been reviewed from authoritative database (HSDB, 2017) to determine the half-life of hydrolysis as a function of pH. The studies are as mentioned below:

In first weight of evidence study the half-life and base catalyzed second order hydrolysis rate constant was determined using a structure estimation method of the test chemical The second order hydrolysis rate constant was determined to be 0.03L/mol-sec with a corresponding half-lives of 7.3 yrs and 270 days at pH 7 and 8, respectively. Based on the half-life values, it is concluded that the chemical is not hydrolysable.

In another study the test chemical is not expected to undergo hydrolysis in the environment due to the lack of functional groups that hydrolyze under environmental conditions

On the basis of the experimental studies of the test chemical and applying the weight of evidence approach, the hydrolysis half-life value of the test chemical can be expected to be ranges 7.3  yr, at pH range 7 and 270 days at pH 8 by second order hydrolysis rate constant. Thus, based on this half-life value, it can be concluded that the test chemical not hydrolysable in water.

Biodegradation:

Biodegradation in water:

Experimental studies for test chemical have been performed for biodegradation endpoint and their results are summarized below.

In first study the 28-days Closed Bottle test following the OECD guideline 301 D was performed to determine the ready biodegradability of the test item. The study was performed at a temperature of 20°C. The test system included control, test item and reference item. Polyseed were used as inoculum with bacterial count as 10E7 to 10E8 CFU/ml. .The concentration of test and reference item (Sodium Benzoate) chosen for both the study was 4 mg/L, while that of inoculum was 32ml/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 39.15 % on 7 days & 61.44 on 14th day. The activity of the inoculum is thus verified and the test can be considered as valid. The BOD28 value of test chemical was observed to be 0.42 mgO2/mg. ThOD was calculated as 3.04 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 13.81 %. Based on the results, the test item, under the test conditions, was considered to be not readily biodegradable in nature.

Another study wa sre viewed from authoritative database in this study the Biodegradation experiment was carried out for determining biodegradability of test chemical in this experiment non adapted activated sludge was used as inoculums at 30 mg/L concentration for 28 days. Biodegradation was analyzed by using two parameters namely O2 cosumption and test material analysis by GC. The initial concentration of test chemical was 100 mg/L. After 28 days of incubation Percent biodegradation of test chemical was observed to be 0.0% by by O2 consumption parameter and 3% test material analysis by GC parameter in 28 days. Therefore it is concluded that test chemical is not readily biodegradable.

On the basis of results of both the studies mentioned above it is concluded that test chemical is not readily biodegradable.

Biodegradation in water and sediments:

Estimation Programs Interface (EPI Suite, 2018) prediction model was run to predict the half-life in water and sediment for the test chemical. If released in to the environment, 17.1 % of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of test chemical in water is estimated to be 37.5  days (900 hrs). The half-life (37.5  days estimated by EPI suite) indicates that the chemical is not persistent in water and the exposure risk to aquatic animals is low , whereas the half-life period of test chemical in sediment is estimated to be  337.5 days (8100 hrs). However, as the percentage release of test chemical into the sediment is less than 3 % (i.e, reported as  2.71 %), indicates that test chemical is not persistent in sediment.

Biodegradation in soil:

The half-life period of test chemical in soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database (EPI suite, 2018). If released into the environment, 79.9 % of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of test chemical in soil is estimated to be 75 days (1800 hrs). Based on this half-life value of test chemical, it is concluded that the chemical is not persistent in the soil environment and the exposure risk to soil dwelling animals is low .

Bioaccumulation:

Predicted data study for target chemical and experimental studies for its read across chemical have been reviewed and their results are summarized below.

The first was done by using BCFBAF Program (v3.00) model of EPI suite (2018) in this study the bio concentration factor (BCF) for test chemical was estimated to be 1985 L/kg wet-wt at 25 deg. c

Further following both the studies were reviewed from authoritative database (HSDB)

The bioaccumulation factor (BCF) value was calculated using a log Kow of 4.35 and a regression-derived equation. The estimated BCF (bioaccumulation factor) value of test chemical was determined to be 450 dimensionless.

In another study the bioaccumulation factor (BCF) value was calculated using an estimated log Kow of 4.39 and a regression derived equation. The BCF (bioaccumulation factor) value of test chemical was determined to be 1300 dimensionless.

By considering result of all the studies mentioned above it is concluded that BCF value of test chemical may be in range of 450 -1985 dimensionless which does not exceed the bioconcentration threshold of 2000 but very close to threshold value, indicating that the chemical can be considered to be bioaccumulative in aquatic organisms.

Transport and distribution:

Adsorption Coefficient:

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 pipetting 4 microliter of test item and diluted with acetonitrile up to 10 ml. Thus, the test solution concentration was 391.2 mg/l. The pH of test substance was 6.2. 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 Acetanilide, 4-chloroaniline, 4-methylaniline(p-Tolouidine), N-methylaniline, p-toluamide, Aniline, 2,5-Dichloroaniline, 4-nitrophenol, 2 - nitrophenol, 2-nitrobenzamide, 3-nitrobenzamide, Nitrobenzene, 4-Nitrobenzamide, 1-naphthylamine, 1-naphtol, Direct Red 81, Benzoic acid methylester, Carbendazim, Benzoic acid phenylester, Xylene, Ethylbenzene, Toluene, Naphthalene, 1,2,3-trichlorobenzene, Pentachlorophenol, Phenol, N,N-dimethylbenzamide, 3,5-dinitrobenzamide, N-methylbenzamide, Benzamide, phenanthrene, DDT were chosen having Koc value range from 1.25 to 5.63. The Log Koc value of test chemical was determined to be 2.321± 0.000 dimensionless at 25°C.This log Koc value indicates that the substance has a low sorption to soil and sediment and therefore has moderate migration potential to ground water.