Diphenylacetonitrile

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 ranges from 42 days to 75 days at pH 4, 5 and 7, respectively. Thus, based on this half-life value, it can be concluded that the test chemical is considered to be hydrolytically stable.

Biodegradation in water

42-days Closed Bottle test following the OECD guideline 301 D to determine the ready biodegradability of the test chemical (Experimental study report, 2019). The study was performed at a temperature of 20°C. The test system included control, test chemical and reference chemical. Polyseed were used as a test inoculum for the study.The concentration of test and reference chemical (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 chemical and reference chemical. The % degradation of procedure control (reference chemical) was also calculated using BOD & ThOD and was determined to be 66.26%. Degradation of Sodium Benzoate exceeds 70.48% on 7 days & 73.49% 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 0.75 mgO2/mg. ThOD was calculated as 2.64 mgO2/mg. Accordingly, the % degradation of the test chemical after 42 days of incubation at 20 ± 1°C according to Closed Bottle test was determined to be 28.4%. Based on the results, the test item, under the test conditions, was considered to be not readily biodegradable in nature.

Bioaccumulation: aquatic / sediment

BCFBAF model of Estimation Programs Interface was used to predict the bioconcentration factor (BCF) of test chemical (2018). The bioconcentration factor (BCF) of test chemical was estimated to be 59.72 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 chemical solution was prepared by accurately weighing 4 mg of test item and diluted with mobile phase up to 10 ml. Thus, the test solution concentration was 400 mg/l. The pH of test substance was 6.85. 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.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, 4-nitrophenol, 2 - nitrophenol, 2-nitrobenzamide, 3-nitrobenzamide, Nitrobenzene, 4 -Nitrobenzamide, 1 -naphthylamine, 1 -naphtol, Direct Red 81, Benzoic acid methylester, Carbendazim, Xylene, Ethylbenzene, Toluene, Naphthalene, 1,2,3-trichlorobenzene, Pentachlorophenol, Phenol, N,Ndimethylbenzamide, 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 3.074±0.000 dimensionless at 25°C.This log Koc value indicates that the substance has a moderate sorption to soil and sediment and therefore have slow 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. 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 EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH) (Directive 92/69/EEC, C.7). Test chemical concentration used for the study was 18.4 mg/l. At the start, each assay was treated with argon (according to guideline) to ensure anaerobic conditions at that time. All test vessels were incubated in the dark. Analytical method involve the use of HPLC. The study was performed at pH of 4, 7 and 9 and temperature of 25°C, respectively. The half-life period of test chemical was determined to be 75 and 42days at pH 4.0 & 7 and temperature of 25°C. Thus, based on this, test chemical is considered to be hydrolytically stable.

 

In an another study, the half-life of the test chemical was determined at different pH range. The study was performed at pH of 5, 7 and 9, respectively. The half-life period of test chemical was determined to be 44 days at pH 5.0 and test chemical was reported to be hydrolytically stable at pH 7 and 9, respectively.

 

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 from 42 days to 75 days at pH 4, 5 and 7, respectively. Thus, based on this half-life value, it can be concluded that the test chemical is considered to be hydrolytically stable.

Biodegradation in water

42-days Closed Bottle test following the OECD guideline 301 D to determine the ready biodegradability of the test chemical (Experimental study report, 2019). The study was performed at a temperature of 20°C. The test system included control, test chemical and reference chemical. Polyseed were used as a test inoculum for the study.The concentration of test and reference chemical (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 chemical and reference chemical. The % degradation of procedure control (reference chemical) was also calculated using BOD & ThOD and was determined to be 66.26%. Degradation of Sodium Benzoate exceeds 70.48% on 7 days & 73.49% 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 0.75 mgO2/mg. ThOD was calculated as 2.64 mgO2/mg. Accordingly, the % degradation of the test chemical after 42 days of incubation at 20 ± 1°C according to Closed Bottle test was determined to be 28.4%. Based on the results, the test item, under the test conditions, was considered to be not readily biodegradable in nature.

Estimation Programs Interface Suite was run to predict the biodegradation potential of the test compound. The screening testsready biodegradability of the test substance was calculated using the software BIOWIN v4.10. The results indicate that Diphenylacetonitrileis not expectedto be readily biodegradablein nature.

Biodegradation study was conducted according to OECD TG 301 C guideline for evaluating the percentage biodegradability of test substance Benzonitrile.Initial test substance conc. used in the study was 100 mg/l. Water, acetone or DMSO solution (0.1 ml) of the test chemicals was added to a mixture of river/sea water (4.9 ml) from an unpolluted area and an autoclaved solution (5.0ml) of 0.2% peptone in a sterile test tube with a tight plug. After sealed with film and fixed at an angle of 30°in a dark box, the test tubes were incubated at 30°C and shaked at 120rpm. Inoculum used for the study was mixed culture obtained from different sources (Sea water from Tama river and River water from Enoshima Beach). The percentage degradation of test substance was found to be 7% and 0% in 14 days, respectively. Thus, the substance Benzonitrile was determined to be not readily biodegradable in nature.

Bioaccumulation: aquatic / sediment

Various predicted data of the test chemical and experimental studies of the read across substance 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 59.72 L/kg whole body w.w (at 25 deg C).

 

In an another prediction done by using Bio-concentration Factor module (ACD (Advanced Chemistry Development)/I-Lab predictive module, 2017)), the bio-concentration Factor of the test chemical was estimated to be 189 at pH range 1-14, respectively.

 

Bioconcentration Factor (BCF) of test chemical was estimated using Chemspider database (modelling database, 2017). The bioconcentration factor of test chemical was estimated to be 202.84 at pH both 5.5 and 7.4, respectively.

 

Another predicted data was estimated using SciFinder database (American Chemical Society (ACS), 2017) for predicting the bioconcentration factor (BCF) of test chemical. The bioconcentration factor (BCF) of test chemical was estimated to be 48 at pH range 1-10 respectively (at 25 deg C).

 

From CompTox Chemistry Dashboard using OPERA (OPEn (quantitative) structure-activity Relationship Application)  V1.02 model in which calculation based on PaDEL descriptors (calculate molecular descriptors and fingerprints of chemical), the bioaccumulation i.e BCF for test chemical was estimated to be 206 dimensionless . The predicted BCF result based on the 5 OECD principles.

 

In a supporting weight of evidence study from authoritative database (2019) and secondary source (2014), bioaccumulation study was conducted on test organism Cyprinus carpio for 8 weeks for evaluating the bioconcentration factor (BCF value) of test chemical.The study was performed according to other guideline "Bioaccumulation test of a chemical substance in fish or shellfish" provided in "the Notice on the Test Method Concerning New Chemical Substances", respectively. Cyprinus carpio was used as a test organism for the study. Test chemical was prepared in HCO-40.Test chemical nominal conc. used for the study was 0.1mg/l and 0.01 mg/l, respectively. Analytical method involve the recovery ratio:Test water: 1st concentration area: 92.2 %, 2nd concentration area : 89.5 %, Fish : 88.7 %, - Limit of detection : Fish : 0.056 ppm.Range finding study involve theTLm(48h) 2.76 ppm (w/v) on Rice fish (Oryzias latipes).The bioconcentration factor (BCF value) of test chemical on Cyprinus carpio was determined to be in the range 452 to 1150 L/Kg at a conc. of 0.1 mg/l and 536 to 1190 L/Kg at a conc. of 0.01 mg/l, respectively.

 

For the test chemical, bioaccumulation study was conducted on test organism Cyprinus carpio for 8 weeks for evaluating the bioconcentration factor (BCF value) of test chemical (J-CHECK, 2019). The study was performed according to other guideline "Bioaccumulation test of a chemical substance in fish or shellfish" provided in "the Notice on the Test Method Concerning New Chemical Substances", respectively. Cyprinus carpio was used as a test organism for the study. Test chemical was prepared in HCO-40.Test chemical nominal conc. used for the study was 0.2mg/l and 0.02 mg/l, respectively. Analytical method involve the recovery ratio: Test water: 1st concentration area: 87.5 %, 2nd concentration area : 95.0 %, Fish : 78.9 %, - Limit of detection : Fish : 0.23 ppm. Range finding study involve the TLm(48h) 18 ppm (w/v) on Rice fish (Oryzias latipes). The bioconcentration factor (BCF value) of test chemical on Cyprinus carpio was determined to be in the range between 171 to 429 L/Kg at a conc. of 0.2 mg/l and 187 to 345 L/Kg at a conc. of 0.02 mg/l, respectively.

 

On the basis of above results of the test chemical, it can be concluded that the BCF value of test chemical was evaluated to beupto 1190, respectively,which does not exceed the bioconcentration threshold of 2000, indicating that the test chemicalis 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 chemical solution was prepared by accurately weighing 4 mg of test item and diluted with mobile phase up to 10 ml. Thus, the test solution concentration was 400 mg/l. The pH of test substance was 6.85. 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.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, 4-nitrophenol, 2 - nitrophenol, 2-nitrobenzamide, 3-nitrobenzamide, Nitrobenzene, 4 -Nitrobenzamide, 1 -naphthylamine, 1 -naphtol, Direct Red 81, Benzoic acid methylester, Carbendazim, Xylene, Ethylbenzene, Toluene, Naphthalene, 1,2,3-trichlorobenzene, Pentachlorophenol, Phenol, N,Ndimethylbenzamide, 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 3.074±0.000 dimensionless at 25°C.This log Koc value indicates that the substance has a moderate sorption to soil and sediment and therefore have slow migration potential to ground water.