Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Biodegradation in water

Biodegradability of 3-methylbutyl benzoate (CAS no. 94 -46 -2) is predicted using QSAR toolbox version 3.3 with logKow as the primary descriptor (2017). Test substance undergoes 81.08% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical 3 -methylbutyl benzoate was estimated to be readily biodegradable in water.

Biodegradation in water and sediment

Estimation Programs Interface (EPI Suite, 2017) prediction model was run to predict the half-life in water and sediment for the test compound  3-methylbutyl benzoate (CAS No. 94 -46 -2). If released in to the environment, 21.7% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of 3-methylbutyl benzoate in water is estimated to be 15 days (360 hrs). The half-life (15 days estimated by EPI suite) indicates that the 3-methylbutyl benzoate is not persistent in water and the exposure risk to aquatic animals is moderate to low whereas the half-life period of 3-methylbutyl benzoate in sediment is estimated to be 135 days (3240 hrs). However, as the percentage release of test chemical into the sediment is less than 1% (i.e, reported as 0.511%), indicates that 3-methylbutyl benzoate is not persistent in sediment.

Biodegradation in soil

The half-life period of test chemical 3-methylbutyl benzoate (CAS No. 94 -46 -2) in soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database (EPI suite, 2017). If released into the environment, 74.6% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of 3-methylbutyl benzoate in soil is estimated to be 30 days (720 hrs). Based on this half-life value of 3-methylbutyl benzoate, 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

Various predicted data for the target compound 3-methylbutyl benzoate (CAS No. 94-46-2) and various supporting weight of evidence studies for its read across substance were reviewed for the biodegradation end point which are summarized as below:

 

In a prediction done by SSS (2017) using OECD QSAR toolbox version 3.3 with logKow as the primary descriptor, percentage biodegradability of test chemical 3-methylbutyl benzoate(CAS No. 94-46-2) was estimated. Test substance undergoes 81.08% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical 3 -methylbutyl benzoate was estimated to be readily biodegradable in water.

 

In another prediction using the Estimation Programs Interface Suite (EPI suite, 2017), the biodegradation potential of the test compound3-methylbutyl benzoate(CAS No. 94-46-2) 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 3-methylbutyl benzoate is expected to be readily biodegradable.

 

In a supporting weight of evidence study from peer reviewed journal (John J. Porter and Eric H. Snider, 1976), biodegradation study was conducted for 30 days for evaluating the percentage biodegradability of read across substance Butyl benzoate (CAS no. 136 -60 -7). Glucose-glutamic acid mixture was used as a reference substance for the biodegradation study. The results are compared with the chemical oxygen demand (COD) of the test chemical, which measures its maximum oxygen combining power; the results are also compared with the BOD test performed on a standard glucose-glutamic acid reference solution used for BOD caliberation. Reference substance i.e; glucose-glutamic acid mixture consumes 75 percent of its maximum oxygen requirement (COD) within 5 days and almost 100 percent in 30 days. Thus, based on this result, the reference substance is considered to be readily biodegradable. The percentage degradation of read across substance was determined to be 50 and 73% degradation by using BOD parameter after 5 and 30 days, respectively. The COD value of read across chemical was determined to be 2200000 mg/l, respectively. Thus, based on percentage degradation, Butyl benzoate is considered to be readily biodegradable in nature.

 

For the same read across chemical Butyl benzoate (CAS no. 136 -60 -7),biodegradation study was conducted for evaluating the percentage biodegradability of read across substance Butyl benzoate using an aerobic dilution method (HSDB, 2016). Test inoculum i.e an adapted culture was obtained from a treatment plant. Initial test substance conc. used in the study was 50 mg/l. The percentage degradation of read across substance was determined to be 100% in 24 hrs. Thus, based on percentage degradation, Butyl benzoate is considered to be readily biodegradable in nature.

 

Another weight of evidence study of biodegradation was conducted for 29 days for evaluating the percentage biodegradability of read across substance Methyl benzoate (CAS no. 93 -58 -3) (HSDB, 2016). The study was performed according to OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test). Activated sludge was used as a test inoculum. Initial test substance conc. used in the study was 28 mg/l. The percentage degradation of read across substance was determined to be 62% degradation by CO2 evolution in 29 days. Thus, based on percentage degradation, Methyl benzoate is considered to be readily biodegradable in nature.

 

On the basis of above results for target chemical 3 -methylbutyl benzoate (from OECD QSAR toolbox version 3.3 and EPI Suite, 2017) and for its read across substance (from peer reviewed journal and authoritative database HSDB, 2016), it can be concluded that the test substance 3 -methylbutyl benzoate can be expected to be readily biodegradable in nature.

Biodegradation in water and sediment

Estimation Programs Interface (EPI Suite, 2017) prediction model was run to predict the half-life in water and sediment for the test compound  3-methylbutyl benzoate (CAS No. 94 -46 -2). If released in to the environment, 21.7% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of 3-methylbutyl benzoate in water is estimated to be 15 days (360 hrs). The half-life (15 days estimated by EPI suite) indicates that the 3-methylbutyl benzoate is not persistent in water and the exposure risk to aquatic animals is moderate to low whereas the half-life period of 3-methylbutyl benzoate in sediment is estimated to be 135 days (3240 hrs). However, as the percentage release of test chemical into the sediment is less than 1% (i.e, reported as 0.511%), indicates that 3-methylbutyl benzoate is not persistent in sediment.

Biodegradation in soil

The half-life period of test chemical 3-methylbutyl benzoate (CAS No. 94 -46 -2) in soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database (EPI suite, 2017). If released into the environment, 74.6% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of 3-methylbutyl benzoate in soil is estimated to be 30 days (720 hrs). Based on this half-life value of 3-methylbutyl benzoate, 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.

On the basis of available information, the test substance 3 -methylbutyl benzoate can be considered to be readily biodegradable in nature.