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Hydrolysis

On the basis of the experimental studies of the structurally and functionally similar read across chemical and applying the weight of evidence approach, the hydrolysis half-life value of the test chemical 1,4-phenylene bis[(4-phenoxyphenyl)-methanone] can be expected to be 47 and 5.1 days at pH 7.0 and 9.0 & at a temperature of 25⁰C, respectively and it was reported to be hydrolytically stable at pH 4 or 55 days, 5.3 days and 13 hrs at pH 8, 9 & 10, respectively iwth a second order hydrolysis rate constant of 0.15L/mol-sec, respectively. Thus, based on this half-life value, it can be concluded that the test chemical 1,4-phenylene bis[(4-phenoxyphenyl)-methanone] is not hydrolysable.

Biodegradation in water

Estimation Programs Interface Suite (2018) was run to predict the biodegradation potential of the test compound  1,4-phenylene bis[(4-phenoxyphenyl)-methanone]  (CAS no. 54299 -17 -1) 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 1,4-phenylene bis[(4-phenoxyphenyl)-methanone] is expected to be not readily biodegradable.

Bioaccumulation: aquatic / sediment

Using Bio-concentration Factor module Bio-concentration Factor of the test substance 1,4-phenylene bis[(4-phenoxyphenyl)-methanone] (CAS no. 54299 -17 -1) was estimated to be 4494347 at pH range 1-14, respectively (ACD (Advanced Chemistry Development)/I-Lab predictive module, 2017)). This value indicates that the test substance 1,4-phenylene bis[(4-phenoxyphenyl)- methanone] was considered to be very bioaccumulative in aquatic organisms.

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 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 3.9. 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, Nitrobenzene, 1-naphthylamine, 1-naphtol, Direct Red 81, Carbendazim, Benzoic acid phenylester, Xylene, Ethylbenzene, Toluene, Naphthalene, 1,2,3-trichlorobenzene, Pentachlorophenol, Phenol, N,Ndimethylbenzamide, 3,5-dinitrobenzamide, N-methylbenzamide, Benzamide, phenanthrene, DDT were chosen having Koc value ranging from 1.25 to 5.63. The Log Koc value was determined to be 4.969± 0.004at 25°C. Thus based on the result it is concluded that the test substance [4-(4-phenoxybenzoyl)phenyl](4-phenoxyphenyl) methanone has a very strong sorption to soil and sediment and therefore has negligible migration potential to ground water.

Additional information

Hydrolysis

Data available for the structurally and functionally similar read across chemicals has been reviewed to determine the half-life of the test chemical 1,4-phenylene bis[(4-phenoxyphenyl)-methan one] (CAS no. 54299 -17 -1). 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 25°C and pH of 4, 7 and 9, respectively. The half-life period of test chemical was determined to be 47 and 5.1 days at pH 7.0 and 9.0, respectively and it was reported to be hydrolytically stable at pH 4 & at a temperature of 25⁰C. On the basis of this, test chemical is considered to be not hydrolysable.

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 0.15L/mol-sec with a corresponding half-lives of 55 days, 5.3 days and 13 hrs at pH 8, 9 and 10, respectively. Based on the half-life value (55 days at pH 8.0), it is concluded that the test chemical is not hydrolysable.

On the basis of the experimental studies of the structurally and functionally similar read across chemical and applying the weight of evidence approach, the hydrolysis half-life value of the test chemical 1,4-phenylene bis[(4-phenoxyphenyl)-methanone] can be expected to be 47 and 5.1 days at pH 7.0 and 9.0 & at a temperature of 25⁰C, respectively and it was reported to be hydrolytically stable at pH 4 or 55 days, 5.3 days and 13 hrs at pH 8, 9 & 10, respectively iwth a second order hydrolysis rate constant of 0.15L/mol-sec, respectively. Thus, based on this half-life value, it can be concluded that the test chemical 1,4-phenylene bis[(4-phenoxyphenyl)-methanone] is not hydrolysable.

Biodegradation in water

Predicted data for the target compound 1,4-phenylene bis[(4-phenoxyphenyl)-methanone](CAS No. 54299-17-1) and various supporting weight of evidence studies for its structurally similar read across substance 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 compound1,4-phenylene bis[(4-phenoxyphenyl)-methanone](CAS No. 54299-17-1) 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 chemical 1,4-phenylene bis[(4-phenoxyphenyl)-methanone]is expected to be not readily biodegradable.

 

In a supporting weight of evidence study from experimental study report (2018),42-days Closed Bottle test following the OECD guideline 301 D 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 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 107 to 108 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 item (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 item and reference item. The % degradation of procedure control (reference item) was also calculated using BOD & ThOD and was determined to be 75.3%. Degradation of Sodium Benzoate exceeds 46.38% on 7 days & 61.44% on 14th day. The activity of the inoculum was thus verified and the test can be considered as valid. The BOD42 value of test chemical was observed to be 0.62 mgO2/mg. ThOD was calculated as 2.31 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 26.83%. Based on the results, the test item, under the test conditions, was 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 substance (authoritative database 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 substance was determined to be 0% by BOD and HPLC parameter 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 target chemical 1,4-phenylene bis[(4-phenoxyphenyl)-methanone] (from modelling database, 2018), it can be concluded that the test substance 1,4-phenylene bis[(4-phenoxyphenyl)-methanone] can be expected to be not readily biodegradable in nature.

Bioaccumulation: aquatic / sediment

Various predicted data for the target compound 1,4-phenylene bis[(4-phenoxyphenyl)-methanone] (CAS No. 54299-17-1) and supporting weight of evidence study for its structurally similar read across substance were reviewed for the bioaccumulation end point which are summarized as below:

 

In a prediction done by using Bio-concentration Factor module (ACD (Advanced Chemistry Development)/I-Lab predictive module, 2017)), Bio-concentration Factor of the test substance 1,4-phenylene bis[(4-phenoxyphenyl)-methanone] (CAS no. 54299 -17 -1) was estimated to be 4494347 at pH range 1-14, respectively. This value indicates that the test substance 1,4-phenylene bis[(4-phenoxyphenyl)-methanone] was considered to be very bioaccumulative in aquatic organisms.

 

Another predicted data was estimated using SciFinder database (American Chemical Society (ACS), 2017) for predicting the bioconcentration factor (BCF) of test chemical 1,4-phenylene bis[(4-phenoxyphenyl)-methanone] (CAS No. 54299 -17 -1). The bioconcentration factor (BCF) of 1,4-phenylene bis[(4-phenoxyphenyl)-methanone] was estimated to be 1000000 at pH range 1-10 respectively (at 25 deg C) which exceeds the bio concentration threshold of 5000, indicating that the chemical 1,4-phenylene bis[(4-phenoxyphenyl)-methanone] is expected to very bioaccumulate in the food chain.

 

In a supporting weight of evidence study from authoritative database (2018) for the test item,the bioaccumulation experiment was conducted for estimating the BCF (bioaccumulation factor) value of test chemical. The bioaccumulation factor (BCF) value was calculated using a measured water solubility of 0.0179 mg/l and a regression-derived equation. The estimated BCF (bioaccumulation factor) value of test chemical was determined to be 5900 dimensionless, which exceeds the bioconcentration threshold of 5000, indicating that the test chemical is considered to be very bioaccumulative in aquatic organisms.

 

On the basis of above results for target chemical 1,4-phenylene bis[(4-phenoxyphenyl)-methanone] (from modelling databases,2017), it can be concluded that the BCF value of test substance 1,4-phenylene bis[(4-phenoxyphenyl)-methanone] ranges from 1000000 –4494347 which exceeds the bioconcentration threshold of 5000, indicating that the chemical 1,4-phenylene bis[(4-phenoxyphenyl)-methanone]  is expected to very 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 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 3.9. 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, Nitrobenzene, 1-naphthylamine, 1-naphtol, Direct Red 81, Carbendazim, Benzoic acid phenylester, Xylene, Ethylbenzene, Toluene, Naphthalene, 1,2,3-trichlorobenzene, Pentachlorophenol, Phenol, N,Ndimethylbenzamide, 3,5-dinitrobenzamide, N-methylbenzamide, Benzamide, phenanthrene, DDT were chosen having Koc value ranging from 1.25 to 5.63. The Log Koc value was determined to be 4.969± 0.004at 25°C. Thus based on the result it is concluded that the test substance [4-(4-phenoxybenzoyl)phenyl](4-phenoxyphenyl) methanone has a very strong sorption to soil and sediment and therefore has negligible migration potential to ground water.