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Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Stability:

Hydrolysis:

Test chemical reacts exothermically with water to form chloral hydrate and the equilibrium constant is 3.6X10-5. On the basis od equilibrium constant value very little test chemical is recovered.

Biodegradation:

Biodegradation in water: secreening tests:

Study was conducted for 28 days for evaluating the percentage biodegradability of test substance in this study the concentration of inoculum i.e, sludge used was 30 mg/l and initial test substance conc. used in the study was 100 mg/l. The percentage degradation of test substance was determined to 8, 0 and 70% by BOD, TOC removal and HPLC parameter in 28 days. Thus, based on percentage degradation (8 and 0%), test chemical is considered to be not readily biodegradable in nature.

Biodegradation in water: simulation tests:

Estimation Programs Interface (EPI Suite, 2020) prediction model was run to predict the half-life in water for the test chemical. If released in to the environment, 46.1% 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 (1440 hrs). The half-life (60 days estimated by EPI suite) indicates that the chemical is persistent in water and the exposure risk to aquatic animals is moderate to high.

Biodegradation in sediments: simulation tests:

Estimation Programs Interface (EPI Suite, 2020) prediction model was run to predict the half-life in sediment for the test chemical. If released in to the environment, the half-life period of test chemical in sediment is estimated to be 541.66 days (13000 hrs). However, as the percentage release of test chemical into the sediment is less than 1% (i.e, reported as 0.0942%), indicates that test cheemical 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 (EPI suite, 2020). If released into the environment, 53.8% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of test cheemical in soil is estimated to be 120 days (2880 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:

Bioaccumulation: aquatic/sediments:

The bioaccumulation study was conducted on fish for determining the BCF (bioaccumulation factor) value of test chemical. The BCF (bioaccumulation factor) was calculated using a log Kow of 1.2 and a regression-derived equation. The BCF (bioaccumulation factor) of test chemical was determined to be 5 dimensionless which does not exceed the bioconcentration threshold of 2000, indicating that the chemical is non-bioaccumulative in aquatic organisms.

Additional information

Stability:

Hydrolysis:

Different studies were performed to determine the hydrolysis rate constant and half-life of test chemical and its structurally similar read across chemicals and results are summarized below

 

In first study from authoritative database the test chemical reacts exothermically with water to form chloral hydrate and the equilibrium constant is 3.6X10-5. On the basis of equilibrium constant value very little test chemical is recovered.

 

Another study was conducted to determine the half-life of hydrolysis of test chemical by using different buffers namely MOPS and carbonates. The half-life of hydrolysis of test chemical was determined to be 9 days and 15 days with hydrolysis rate constant of 1.1E-3/h and 1.8E-3/h respectively. On the basis of half-life values test chemical is considered to be hydrolysable.

 

By considering results of both the studies test chemical is considered to be hydrolysable.   

Biodegradation:          

Biodegradation in water: Screening test :

Different studies were performed to determine the Biodegradation in water of test chemical and its structurally similar read across chemical and results are summarized below.

In the first study from authoritative database the experiment was conducted for 28 days for evaluating the percentage biodegradability of test substance in this study the concentration of inoculum i.e, sludge used was 30 mg/l and initial test substance conc. used in the study was 100 mg/l. The percentage degradation of test substance was determined to 8, 0 and 70% by BOD, TOC removal and HPLC parameter in 28 days. Thus, based on percentage degradation (8 and 0%), test chemical is considered to be not readily biodegradable in nature.

 

In next study the Estimation Programs Interface Suite (EPI suite, 2020) 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 chemical is expected to be not readily biodegradable.

 

To support the above results another study was conducted for 14 days for evaluating the percentage biodegradability of test substance in this study the concentration of inoculum i.e, sludge used was 30 mg/l and initial test substance conc. used in the study was 100 mg/l. The percentage degradation of test substance was determined to be 0 % by O2 consumption (BOD) and test chemical analysis by GC parameter in 14 days. Thus, based on percentage degradation value, test chemical is considered to be not readily biodegradable in nature.

 

By considering the results of all the studies mentioned above it is concluded that test chemical is not readily biodegradable in nature.

Biodegradation in water: simulation tests:

Estimation Programs Interface (EPI Suite, 2020) prediction model was run to predict the half-life in water for the test chemical. If released in to the environment, 46.1% 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 (1440 hrs). The half-life (60 days estimated by EPI suite) indicates that the chemical is persistent in water and the exposure risk to aquatic animals is moderate to high.

Biodegradation in sediments: simulation tests:

Estimation Programs Interface (EPI Suite, 2020) prediction model was run to predict the half-life in sediment for the test chemical. If released in to the environment, the half-life period of test chemical in sediment is estimated to be 541.66 days (13000 hrs). However, as the percentage release of test chemical into the sediment is less than 1% (i.e, reported as 0.0942%), indicates that test cheemical 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 (EPI suite, 2020). If released into the environment, 53.8% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of test cheemical in soil is estimated to be 120 days (2880 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:

Bioaccumulation: aquatic/sediments:

Various experimental study and predicted data for the test chemical and its structurally similar read across chemical were reviewed for the bioaccumulation end point which are summarized as below:

 

The first bioaccumulation study was conducted on fish for determining the BCF (bioaccumulation factor) value of test chemical. The BCF (bioaccumulation factor) was calculated using a log Kow of 1.2 and a regression-derived equation. The BCF (bioaccumulation factor) of test chemical was determined to be 5 dimensionless which does not exceed the bioconcentration threshold of 2000, indicating that the chemical is non-bioaccumulative in aquatic organisms.

 

In another study the BCFBAF model (v3.01) of Estimation Programs Interface (EPI Suite, 2020) program 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 °C which does not exceed the bioconcentration threshold of 2000, indicating that the test chemical is non-bioaccumulative in nature.

 

In next study using Bio-concentration Factor (v12.1.0.50374) module, the BCF over the entire pH scale (pH 0 - 14) of the test chemical was estimated to be 9.85 (log BCF = 1.0 ± 1.0). This value indicates that the test chemical was considered to be non-bioaccumulative in aquatic organisms.

 

In last bioaccumulation study in fish was conducted for estimating the BCF (bioaccumulation factor) value of test chemical. The bioaccumulation factor (BCF) value was calculated using a log Kow of 0.99 and a regression-derived equation. The estimated BCF (bioaccumulation factor) value of test chemical was determined to be 3 dimensionless, which does not exceed the bioconcentration threshold of 2000, indicating that the test chemical is considered to be non-bioaccumulative in aquatic organisms.

 

On the basis of above results for test chemical, it is concluded that the BCF value of test chemical ranges from 3.162 – 9.85 dimensionless which does not exceed the bioconcentration threshold of 2000, indicating that the chemical is not expected to bioaccumulate in the food chain.

Transport and distribution:

Adsorption/desorption:

Various predicted data for the test chemical were reviewed for the adsorption end point and their results are summarized as below:

 

In first study the Adsorption experiment was conducted for estimating the adsorption coefficient (Koc) value of test chemical. The adsorption coefficient (Koc) value was calculated using a water solubility of 8300000 mg/L and regression derived equation. The adsorption coefficient (Koc) value of test chemical was determined to be 0.68 (Log Koc = -0.167). This Koc value indicates that the test chemical has a negligible sorption to soil and sediment and therefore have a rapid migration potential to groundwater.

 

In next study the KOCWIN model (v2.00) of Estimation Programs Interface (EPI Suite, 2020) was used to predict the soil adsorption coefficient i.e Koc value of test chemical. The soil adsorption coefficient i.e Koc value of test chemical was estimated to be 2.138 L/kg (log Koc=0.33)  by means of MCI method at 25 °C. This Koc value indicates that the test chemical has a negligible sorption to soil and sediment, rapid migration to ground water.

 

In another study the Soil Adsorption Coefficient i.e Koc value of test chemical was estimated using Adsorption Coefficient module (v12.1.0.50374) program as Koc 179 (log Koc = 2.3 ± 1.0). This Koc value indicates that the test chemical has a low sorption to soil and sediment and therefore have moderate migration to ground water.

 

Last study was experimental study in this 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 chemical solution was prepared by accurately weighing 50mg of test chemical and diluted with mobile phase up to 100ml. Thus, the test solution concentration was 500mg/l. The pH of test substance was 6.24. 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 structural similarity with the test substance and calibration graph was prepared. The reference substances were 2- Nitrobenzamide, p – Toluamide, 4 – methyl aniline, Aniline, N – methyl aniline, 2,5 Dichloroaniline having Koc value ranging from 1.45 to 2.58. The Log Koc value of test chemical was determined to be 1.645 ± 0.003 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.

 

On the basis of above results for test chemical it is concluded that the Koc value of test chemical ranges from -0.167 to- 2.3 dimensionless indicating that the test chemical has negligible to low sorption to soil and sediment and therefore have rapid to moderate migration potential to ground water.

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