12-hydroxy-N-(2-hydroxyethyl)octadecan-1-amide

Endpoint summary

Description of key information

Hydrolysis

HYDROWIN v2.00 program of Estimation Programs Interface (2018) prediction model was used to predict the hydrolysis half-life of test chemical. The estimated half-life of test chemical was determined to be 38000 yrs at pH 7.0 and at a temperature of 25ᵒC.

Biodegradation in water

Estimation Programs Interface Suite (EPI suite, 2018) was run to predict the biodegradation potential of the test compound 12-hydroxy-N-(2-hydroxyethyl) octadecan-1-amide (CAS no.  106 -15 -0) 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 chemical 12-hydroxy-N-(2-hydroxyethyl)octadecan-1-amide is expected to be readily biodegradable.

Biodegradation in water and sediment

Estimation Programs Interface (2018) prediction model was run to predict the half-life in water and sediment for the test chemical. If released in to the environment, 21.9% 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 15 days (360 hrs). The half-life (15 days estimated by EPI suite) indicates that the chemical is not persistent in water and the exposure risk to aquatic animals is moderate to low whereas the half-life period of test chemical in sediment is estimated to be 135 days (3240 hrs). However, as the percentage release of test chemical into the sediment is less than 1% (i.e, reported as 0.545%), 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 (2018). If released into the environment, 77.2% 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 30 days (720 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 moderate to low.

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, 2018). 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 Methanol up to 10 ml. Thus, the test solution concentration was 400 mg/l. The pH of test substance was 6.8. 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 functionally similarity with the test substance and calibration graph prepared. The reference substances were Benzamide, Nitrobenzene, 4-Nitrobenzamide, N,N-dimethylbenzamide, N-methylbenzamide, 2- nitrophenol having Koc value ranging from 1.239 to 2.47. The Log Koc value of test chemical was determined to be 1.801± 0.00 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

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

 

In a prediction done using the HYDROWIN v2.00 program of Estimation Programs Interface (2018), the hydrolysis half-life of test chemical was estimated. The estimated half-life of test chemical was determined to be 38000 yrs at pH 7.0 and at a temperature of 25ᵒC.

 

In a supporting study from authoritative database (2017), 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 of test chemical was determined to be 0.030L/mol-sec with a corresponding half-lives of 7.3 yrs and 270 days at pH 7 and 8, respectively.

 

For the test chemical, the base catalyzed second order hydrolysis rate constant was determined using a structure estimation method of the test chemical (HSDB and PubChem, 2017). The second order hydrolysis rate constant of test chemical was determined to be 0.03L/mol-sec with a corresponding half-lives of 7.3 yrs and 266 days at pH 7 and 8, respectively.

 

On the basis of above results for test chemical, it can be concluded that the half-life value of test chemical was evaluated to be ranges from 266 days to 38000 yrs, respectively.

Biodegradation in water

Predicted data study for target chemical 12-hydroxy-N-(2-hydroxyethyl)octadecan-1-amide (CAS no.  106 -15 -0) and experimental studies for its structurally and functionally similar read across chemicals have been conducted and their results are summarized below.

In first predicted data study the Estimation Programs Interface Suite (EPI suite, 2018) was run to predict the biodegradation potential of the test compound 12-hydroxy-N-(2-hydroxyethyl)octadecan-1-amide (CAS no.  106 -15 -0) 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 chemical 12-hydroxy-N-(2-hydroxyethyl)octadecan-1-amide is expected to be readily biodegradable.

In an another study. the test chemical was subjected to biodegradation test by taking activated sludge as inoculums at 30 mg/L concentration. Biodegradation was analysed by using two parameters namely BOD and GC. The initial concentration of test chemical was 100 mg/L.The test chemical showed 52 % biodegradability by BOD parameter and 73 % by GC parameter by using activated sludge as inoculumin 28 days. On the basis of percent biodegradability it is concluded that test chemical is readily biodegradable.

 

By considering results of all the studies mentioned above it can be concluded that test chemical 12-hydroxy-N-(2-hydroxyethyl)octadecan-1-amide (CAS no.  106 -15 -0) is expected to be readily biodegradable in nature.

Biodegradation in water and sediment

Estimation Programs Interface (2018) prediction model was run to predict the half-life in water and sediment for the test chemical. If released in to the environment, 21.9% 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 15 days (360 hrs). The half-life (15 days estimated by EPI suite) indicates that the chemical is not persistent in water and the exposure risk to aquatic animals is moderate to low whereas the half-life period of test chemical in sediment is estimated to be 135 days (3240 hrs). However, as the percentage release of test chemical into the sediment is less than 1% (i.e, reported as 0.545%), 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 (2018). If released into the environment, 77.2% 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 30 days (720 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 moderate to low.

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, 2018). 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 Methanol up to 10 ml. Thus, the test solution concentration was 400 mg/l. The pH of test substance was 6.8. 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 functionally similarity with the test substance and calibration graph prepared. The reference substances were Benzamide, Nitrobenzene, 4-Nitrobenzamide, N,N-dimethylbenzamide, N-methylbenzamide, 2- nitrophenol having Koc value ranging from 1.239 to 2.47. The Log Koc value of test chemical was determined to be 1.801± 0.00 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.