2-[2-[4-(diethylamino)phenyl]vinyl]-1,3,3-trimethyl-3H-indolium acetate

Endpoint summary

Description of key information

Hydrolysis:

HYDROWIN programe was use to estimate the half life of test chemical. The half life of test chemical was estimated to be 16.3 days at pH 7 and 1.63 days at pH 8.

Biodegradation in water: screening test:

Estimation Programs Interface Suite (EPI suite, 2018) was run to predict the biodegradation potential of the test compound 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 is expected to be not readily biodegradable.

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, 3.66 % 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 60 days (541.6 hrs). The half-life (60 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 541.6 days (1.3e+004 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 (EPI suite). If released into the environment, 58.3 % 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 120 days (2.88e+003 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:

Using BCFBAF Program (v3.00) model of EPI suite (2018) the estimated bio concentration factor (BCF) for test chemical is 3.162 L/kg wet-wt at 25 °C which does not exceed the bioconcentration threshold of 2000. Therefore it is concluded that test chemical is non-bioaccumulative in food chain.

Adsorption:

2: The Adsorption Coefficient of test substance was determined as per the HPLC method (OECD Guideline-121). The Log Koc value was determined to be 2.294± 0.002 at 25°C.

3: The Adsorption Coefficient of test substance was determined as per the HPLC method (OECD Guideline-121). The Log Koc value was determined to be 2.169 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.

Thus based on the above study results, it is concluded that the test chemical has a low sorption to soil and sediment and therefore has moderate migration potential to ground water.

Additional information

Hydrolysis:

HYDROWIN programe was use to estimate the half life of test chemical. The half life of test chemical was estimated to be 16.3 days at pH 7 and 1.63 days at pH 8.

Biodegradation in water: screening test:

Various studies have been summarized for the determination of biodegradation rate of test chemical and structurally and functionally similar read across chemicals which are reviewed and mention as below:

 

Estimation Programs Interface Suite (EPI suite, 2018) was run to predict the biodegradation potential of the test compound 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 is expected to be not readily biodegradable.

 

Above data further supported by the second experimental data from peer reviewed journal. Biodegradation study was carried out for 42 days for evaluating the percentage biodegradation of the test chemical using modified OECD Guideline 302B. Activated sludge was used as a test inoculum. The sources of the activated sludge were treatment plants conveniently located to the laboratories carrying out the test. These treatment plants received communal and/or industrial wastewater. Concentration of inoculum i.e, activated sludge used was 0.5 g/l and initial test substance conc. used in the study was 100 mg/l. Analytical methods involve the measurement of extinction at absorption maximum 412 nm and DOC (dissolved organic carbon).The percentage degradation of the test substance was determined to be 16% by using DOC removal parameter in 42 days. Thus, based on percentage degradation, test chemical was considered to be not readily biodegradable in nature.

 

Similarly in the third study from experimental source, 35-days Closed Bottle test was performed following the OECD guideline 301D to determine the ready biodegradability of the test chemical. The test system included control, test chemical and reference item. 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. 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 BOD35 value of test chemical was observed to be 0.52 mgO2/mg. ThOD was calculated as 2.31 mgO2/mg. Accordingly, the % degradation of the test item after 35 days of incubation at 20 ± 1°C according to Closed Bottle test was observed to be 22.51%. Based on the results, the test chemical under the test conditions was considered to be not readily biodegradable.

 

Thus based on the above all studies and result observations, it is concluded that the test chemical is not readily biodegradable.

 

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, 3.66 % 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 60 days (541.6 hrs). The half-life (60 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 541.6 days (1.3e+004 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 (EPI suite). If released into the environment, 58.3 % 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 120 days (2.88e+003 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:

Based on the predicted and experimental data of test chemical and read across chemicals has been reviewed to study the bioaccumulation rate of test chemical. All the studies are as mentioned below:

 

Using BCFBAF Program (v3.00) model of EPI suite (2018) the estimated bio concentration factor (BCF) for test chemical is 3.162 L/kg wet-wt at 25 °C which does not exceed the bioconcentration threshold of 2000. Therefore it is concluded that test chemical is non-bioaccumulative in food chain.

 

Similar data 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 substance was estimated to be 462 dimensionless. The predicted BCF result based on the 5 OECD principles. Thus based on the result it is concluded that the test substance is non-bioaccumulative in nature.

 

Above data further supported by the experimental data from authoritative database. Bioaccumulation test was conducted for 28 days for determination the bioconcentration factor (BCF) and lipid content of test substance on test organism. Test conducted according to the OECD Guideline 305 (Bioconcentration: Flow-through Fish Test). Cyprinus carpio was used as a test organism. Range finding study was conducted on Rice fish (Oryzias latipes). 1 µg/L and 10 µg/L concentrations was used in the study. Study conducted under the flow-through system for 96 hours.Bioconcentration factor was calculated in the interval of 9 days, 13 days, 15 days, 20 days and 28 days. By analytical methods, the limit of quantification was found to be 0.18 µg/l in 1st concentration area and 0.018µg/l 2nd concentration area. Whereas the lipid content at the start and end of exposure was observed to be 2.87% and 1.94%, respectively. Under the test condition, the BCF value for test substance was observed to be ≤ 0.91 L/kg at dose concentration 10 micro g/L and ≤ 9.1 L/kg at dose concentration 1 micro g/L on test organism Cyprinus carpio during 28 day period. These values indicate that the substance is not bioaccumulative.

 

Based on the above studies and various data, it is observed that the substance is not bioaccumulative. As it does not exceed the bioconcentration threshold of 2000. Therefore it is concluded that test chemical is non-bioaccumulative in food chain.

 

Adsorption:

Summarized result for the determination of adsorption of test chemical and structurally and functionally similar read across chemicals has been studied and mention as below:

 

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 pipetting 4 microliter of test item and diluted with Acetonitrile up to 10 ml. Thus, the test solution concentration was 44.92 mg/l (calculated according to its density). The pH of test substance was 8.1. 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 there with, 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, 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 2.294± 0.002 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.

 

 

Above study was further supported by another weight of evidence from experimental source. 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 pipetting 4 microlitre of test item and diluted with Acetonitrile up to 10 ml. Thus, the test solution concentration was 545.6 mg/l(calculated according to density). The pH of test substance was 8.8. 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 4-methylaniline(p-Tolouidine), N-methylaniline, Aniline, Xylene, Ethylbenzene, Toluene, Naphthalene were chosen having Koc value range from 1.9 to 2.75. The Log Koc value of test chemical was determined to be 2.169±0.001 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.

 

Thus based on the above study results, it is concluded that the test chemical has a low sorption to soil and sediment and therefore has moderate migration potential to ground water.