N-tert-butylacrylamide

Endpoint summary

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 135, 14.6 and 1.5 years at pH 7, 8 and 9, respectively at 20 deg C. Thus, based on this half-life value, it can be concluded that the test chemical is not hydrolysable.

Biodegradation:

Biodegradation in water:

42-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 a test inoculum.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 78.31  %. Degradation of Sodium Benzoate exceeds 42.16  % on 7 days &  63.25 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 0.8 mgO2/mg. ThOD was calculated as 2.26 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  35.39 %. Based on the results, the test item, under the test conditions, was considered to be primary inherently biodegradable in nature.

Biodegradation in water and sediment:

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,29 % 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 1% (i.e, reported as 0.0916 %), indicates that test chemical is not persistent in sediment.

Biodegradation in soil:

The half-life period of test chemicalin soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database (EPI suite, 2018). If released into the environment, 70.7 % 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 2.19 L/kg wet-wt at 25 deg. c which does not exceed the bioconcentration threshold of 2000. Therefore it is concluded that test chemica is nonbioaccumulative in food chain.

Transport and distribution:

Adsorption coefficient:

The Adsorption Coefficient of test substancevwas determined as per the HPLC method (OECD Guideline-121). The Log Koc value was determined to be 1.869  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:

Various studies have been reviewed to determine the half-life of the test chemical. The studies are as mentioned below:

The first study was reviewed from authoritative database (HSDB) in this study the half-life and acid & base catalyzed hydrolysis rate constant of the test chemical was determined at a temperature of 20°C. The acid and based catalyzed hydrolysis rate constant of test chemical was determined to be 12600 & 0.0015 L/mol-sec, respectively with a corresponding half-lives of 135, 14.6 and 1.5 years at pH 7, 8 and 9, respectively.

In another study the Electronegative groups on carbon or nitrogen greatly accelerate base catalyzed hydrolysis, but alkyl groups on nitrogen retard both acid and base catalyzed processes and No neutral hydrolysis is evident.

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 135, 14.6 and 1.5 years at pH 7, 8 and 9, respectively at 20 deg C. Thus, based on this half-life value, it can be concluded that the test chemical is not hydrolysable.

Biodegradation:

Biodegradation in water:

42-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 a test inoculum.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 78.31  %. Degradation of Sodium Benzoate exceeds 42.16  % on 7 days &  63.25 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 0.8 mgO2/mg. ThOD was calculated as 2.26 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  35.39 %. Based on the results, the test item, under the test conditions, was considered to be primary inherently biodegradable in nature.

Biodegradation in water and sediment:

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,29 % 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 1% (i.e, reported as 0.0916 %), indicates that test chemical is not persistent in sediment.

Biodegradation in soil:

The half-life period of test chemicalin soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database (EPI suite, 2018). If released into the environment, 70.7 % 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:

Different studies have been conducted for test chemical and its read across chemical for bioaccumulation in aquatic organisms endpoint and their results are summarized below.

The first study was done by using BCFBAF Program (v3.00) model of EPI suite (2018) and bio concentration factor (BCF) for test chemical  was estimated to be 2.19 L/kg wet-wt at 25 deg. c
 

Next study was reviewed from authoritative database (HSDB) in this study the BCF value of test chemical estimated was 3.0 dimensionless by using an estimated log Kow of 0.57 and a regression-derived equation and it is far less than 2000 criteria of CLP regulation.

By considering both studies mentioned above it is concluded that test chemical is non bioaccumulative.

Bioaccumulation endpoint can also be considered for waiver in accordance with column 2 of Annex IX of the REACH regulation, testing for this endpoint is scientifically not necessary and does not need to be conducted since the test chemical has a low potential for bioaccumulation based on logKow ≤ 3.

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 weighing 4 mg of test item and diluted with Acetonitrile up to 10 ml. Thus, the test solution concentration was 400 mg/l. The pH of test substance was 5.3 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 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-naphthol, 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 having Koc value ranging from 1.25 to 5.63. The Log Koc value of test chemical was determined to be 1.869 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.