Ethyltriphenylfosfonium bromide

Endpoint summary

Description of key information

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 > 5 days at pH 4, 7 and 9 & at a temperature of 50⁰C or 1.4 yrs and 51 days at pH 7 and 8 with a second order hydrolysis rate constant of 0.16 L/mol-sec, respectively. Thus, based on this half-life value, it can be concluded that the test chemical is not hydrolysable.

Biodegradation in water

Estimation Programs Interface Suite (2018) was run to predict the biodegradation potential of the test chemical 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 test chemical is expected to be not 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 compound. If released in to the environment, 2.76% 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 moderate to low whereas the half-life period of test chemical in sediment is estimated to be 337.5 days (8100 hrs). Based on this half-life value, it indicates that test chemical is 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, 36.2% of th 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 moderate to low.

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 deg 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, 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 5 ml water and make with Methanol up to 10 ml. Thus, the test solution concentration was 400 mg/l. The pH of test substance was 5.6. 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 estimated Koc range of the test substance and generalized calibration graph was prepared. The reference substances were Acetanilide, 4-chloroaniline, 4-methylaniline(p-Tolouidine), N-methylaniline, p-toluamide, Aniline, 2,5-Dichloroaniline, 2 - nitrophenol, 3-nitrobenzamide, Nitrobenzene, 4-Nitrobenzamide, Carbendazim, Benzoic acid phenylester, Xylene, Ethylbenzene, Toluene, Naphthalene, N,N-dimethylbenzamide, 3,5-dinitrobenzamide, 1,2,3 -trichlorobenzene having Koc value ranging from 1.25 to 3.16. The Log Koc value of test chemical was determined to be 1.255 ± 0.023 at 25°C. This log Koc value indicates that the test substance has a negligible sorption to soil and sediment and therefore have rapid migration potential to ground water.

Additional information

Hydrolysis

Data available for the test chemical has been reviewed to determine the half-life of hydrolysis as a function of pH. 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 and pH of 4, 7 and 9, respectively. The average percentage recovery of the test chemical after 5 days was determined to be 96.5, 97.5 and 98.6% at pH 4, 7 and 9, respectively. As no hydrolysis of test chemical 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 chemical is not hydrolysable.

 

For the test chemical, the hydrolysis half-life was determined. Although half-life value of test chemical was not known, but it was noted that chemical is not susceptible to hydrolysis and thus it was reported to be hydrolytically stable. On the basis of this, test chemical isconsidered to be not hydrolysable.

 

In an another 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 of test chemical was determined to be 0.16L/mol-sec with a corresponding half-lives of 1.4 yrs and 51 days at pH 7 and 8, respectively. Based on the half-life values, it is concluded that the test chemical is not hydrolysable.

 

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 > 5 days at pH 4, 7 and 9 & at a temperature of 50⁰C or 1.4 yrs and 51 days at pH 7 and 8 with a second order hydrolysis rate constant of 0.16 L/mol-sec, respectively. Thus, based on this half-life value, it can be concluded that the test chemical is not hydrolysable.

Biodegradation in water

Predicted data and various experimental studies of the test chemical were reviewed for the biodegradation end point which are summarized as below:

 

In a prediction using the Estimation Programs Interface Suite (2018), the biodegradation potential of the test chemical in the presence of mixed populations of environmental microorganisms was estimated. 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 test chemical is expected to be not readily biodegradable.

 

In a supporting weight of evidence study from secondary source (2006) for the test item,biodegradation experiment was conducted for 28 days for evaluating the percentage biodegradability of test chemical. The study was performed according to equivalent or similar OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test) under aerobic conditions. Peptone was used as a co-substrate. Industrial sludge was used as a test inoculums for the study. Initial test chemical concentration used for the study was 200 mg/l. No inhibition of bacterial growth by test chemical was observed in a pre-test. The percentage degradation of test chemical was determined to be < 20% by O2 consumption in 28 days. Thus, based on percentage degradation, test chemical is considered to be not readily biodegradable in nature.

 

For the test chemical, biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of test chemical (J-CHECK, 2018). Activated sludge was used as a test inoculums for the study. Concentration of inoculum i.e, sludge used was 30 mg/l and initial test substance conc. used in the study was 100 mg/l, respectively. The percentage degradation of test chemical was determined to be 0% by O2 consumption, BOD, TOC removal, Test material analysis and HPLC parameter in 28 days. Thus, based on percentage degradation, test chemical is considered to be not readily biodegradable in nature.

 

In a supporting weight of evidence study, biodegradation experiment was conducted for 28 days for evaluating the percentage biodegradability of test chemical (IUCLID dataset, 2000). The study was performed according to other guideline EEC Directive 79–831 Annex V under aerobic conditions. Activated sludge, domestic was used as a test inoculums for the study. The percentage degradation of test chemical was determined to be <10% by Test material analysis parameter in 28 days. Thus, based on percentage degradation, test chemical is considered to be not readily biodegradable in nature.

 

Another biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of test chemical (secondary source, 2000). The study was performed according to OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test) under aerobic conditions. Municipal activated sludge was used as a test inoculums for the study. The percentage degradation of test chemical was determined to be < 20% by O2 consumption in 28 days. Thus, based on percentage degradation, test chemical is considered to be not readily biodegradable in nature.

 

On the basis of above results for test chemical, it can be concluded that the test chemical can be expected to be not 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 compound. If released in to the environment, 2.76% 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 moderate to low whereas the half-life period of test chemical in sediment is estimated to be 337.5 days (8100 hrs). Based on this half-life value, it indicates that test chemical is 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, 36.2% of th 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 moderate to low.

On the basis of available information, the test chemical can be considered to be not readily biodegradable in nature.

Bioaccumulation: aquatic / sediment

Predicted data and various experimental studies of the test chemical were reviewed for the bioaccumulation end point which are summarized as below:

 

In a prediction done using the BCFBAF Program 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 deg C).

 

In a supporting weight of evidence study from secondary source (2006) for the test chemical,bioaccumulation experiment was conducted for estimating the BCF (bioaccumulation factor) value of test chemical. The bioaccumulation factor (BCF) value was calculated using an experimental logKow of 2.83. The estimated BCF (bioaccumulation factor) value of test chemical was determined to be 30 dimensionless.

 

For the test chemical, the bioaccumulation study was conducted for estimating the BCF (bioaccumulation factor) value of test chemical (HSDB, 2017). The bioaccumulation factor (BCF) value was calculated using a measured water solubility of 1.51 mg/l and a regression-derived equation. The estimated BCF (bioaccumulation factor) value of test chemical was determined to be 500 dimensionless.

 

On the basis of above overall results for test chemical, it can be concluded that the log Koc value of test chemical was estimated to be upto 500 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 (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 5 ml water and make with Methanol up to 10 ml. Thus, the test solution concentration was 400 mg/l. The pH of test substance was 5.6. 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 estimated Koc range of the test substance and generalized calibration graph was prepared. The reference substances were Acetanilide, 4-chloroaniline, 4-methylaniline(p-Tolouidine), N-methylaniline, p-toluamide, Aniline, 2,5-Dichloroaniline, 2 - nitrophenol, 3-nitrobenzamide, Nitrobenzene, 4-Nitrobenzamide, Carbendazim, Benzoic acid phenylester, Xylene, Ethylbenzene, Toluene, Naphthalene, N,N-dimethylbenzamide, 3,5-dinitrobenzamide, 1,2,3 -trichlorobenzene having Koc value ranging from 1.25 to 3.16. The Log Koc value of test chemical was determined to be 1.255 ± 0.023 at 25°C. This log Koc value indicates that the test substance has a negligible sorption to soil and sediment and therefore have rapid migration potential to ground water.