Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

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.

Additional information

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.