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Biodegradation in water:

Biodegradability of test chemical 4-methoxy-2-methyl-N-phenylaniline (CAS no. 41317 -15 -1) was estimated by using OECD QSAR tool box v3.3 by considering eight closest read across chemicals with log Kow as primary descriptor. Percent degradability of test chemical 4-methoxy-2-methyl-N-phenylaniline was estimated to be 0.550 % by considering BOD as parameter  and microorganisms as inoculum in 28 days. On the basis of percent degradability value it is concluded that this test chemical is not readily biodegradable.

Biodegradation in water and sediments:

Estimation Programs Interface (EPI Suite, 2017) prediction model was run to predict the half-life in water and sediment for the test compound 4-methoxy-2-methyl-N-phenylaniline (CAS No. 41317 -15 -1). If released in to the environment, 35 % 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 37.5 days (900 hrs). The half-life (37.5 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 4-methoxy-2-methyl-N-phenylaniline in sediment is estimated to be 337.5 days (8100 hrs). However, as the percentage release of test chemical into the sediment is less than 1 % (i.e, reported as 0.0835 %), indicates that test chemical 4-methoxy-2-methyl-N-phenylaniline is not persistent in sediment.

Biodegradation in soil:

The half-life period of test chemical 4-methoxy-2-methyl-N-phenylaniline (CAS No. 41317 -15 -1) 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, 81.2 % of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of test chemical 4-methoxy-2-methyl-N-phenylaniline in soil is estimated to be 75.0 days (1800 hrs). Based on this half-life value of test chemical 4-methoxy-2-methyl-N-phenylaniline, it is concluded that the chemical is not persistent in the soil environment and the exposure risk to soil dwelling animals is low .

Additional information

Biodegradation in water:

Predicted data for the target compound 4-methoxy-2-methyl-N-phenylaniline (CAS no. 41317 -15 -1)and supporting weight of evidence studies for its structurally similar read across substance were reviewed for the biodegradation end point which are summarized as below:

 

In first predicted data study the biodegradability of test chemical 4-methoxy-2-methyl-N-phenylaniline (CAS no. 41317 -15 -1) was estimated by using OECD QSAR tool box v3.3 by considering eight closest read across chemicals with log Kow as primary descriptor. Percent degradability of test chemical 4-methoxy-2-methyl-N-phenylaniline was estimated to be 0.550 % by considering BOD as parameter and microorganisms as inoculum in 28 days. On the basis of percent degradability value it is concluded that this test chemical is not readily biodegradable.

 

Next predicted data study was done by using estimation Programs Interface Suite (EPI suite, 2017) to estimate the biodegradation potential of the test compound 4-methoxy-2-methyl-N-phenylaniline (CAS no. 41317 -15 -1) 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 Biowin 1-7, respectively) of the BIOWIN v4.10 software. The results indicate that chemical 4-methoxy-2-methyl-N-phenylanilineis expected to be not readily biodegradable.

 

Further to support the above studies of target chemical experimental study have been conducted for read across chemical from authoritative database J- CHECK (2017)in this study Biodegradation experiment was conducted for 28 days for evaluating the percentage biodegradability of read across substance 2-(2-Methylpropoxy) naphthalene. Concentration of inoculum i.e, sludge used was 30 mg/l and initial test substance conc. used in the study was 100 mg/l, respectively. The percentage degradation of test substance was determined to be 1 and 19% by BOD and HPLC parameters respectively in 28 days. Thus, based on percentage degradation, 2-(2-Methylpropoxy)naphthalene is considered to be not readily biodegradable in nature.

 

One more experimental study have been conducted to support predicted data of target chemical same source as mentioned above (J-CHECK, 2017) in this study read across chemical Benzenamine, N-phenyl- (CAS no.122 -39 -4) was subjected to biodegradation test by taking activated sludge as inoculums at 30 mg/L concentration. Biodegradation was analysed by using three parameter namely BOD, GC and UV Vis . The initial concentration of read across chemical was 100 mg/L. The read across chemical Benzenamine, N-phenyl- showed 0 % biodegradability by BOD parameter 6.5 % by GC parameter and 5.0 % by UV vis parameter by using activated sludge as inoculumin 14 days. On the basis of percent biodegradability it is concluded that read acros chemical Benzenamine, N-phenyl- is not readily biodegradable.

 

On the basis of results of above mentioned studies for target chemical 4-methoxy-2-methyl-N-phenylaniline (CAS no. 41317 -15 -1) (from OECD QSAR tool box v3.3 and EPI suite) and supporting weight of evidence study (from J Check, 2017). It is concluded that the test chemical 4-methoxy-2-methyl-N-phenylaniline can be expected to be not readily biodegradable.

Biodegradation in water and sediments:

Estimation Programs Interface (EPI Suite, 2017) prediction model was run to predict the half-life in water and sediment for the test compound 4-methoxy-2-methyl-N-phenylaniline (CAS No. 41317 -15 -1). If released in to the environment, 35 % 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 37.5 days (900 hrs). The half-life (37.5 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 4-methoxy-2-methyl-N-phenylaniline in sediment is estimated to be 337.5 days (8100 hrs). However, as the percentage release of test chemical into the sediment is less than 1 % (i.e, reported as 0.0835 %), indicates that test chemical 4-methoxy-2-methyl-N-phenylaniline is not persistent in sediment.

Biodegradation in soil:

The half-life period of test chemical 4-methoxy-2-methyl-N-phenylaniline (CAS No. 41317 -15 -1) 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, 81.2 % of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of test chemical 4-methoxy-2-methyl-N-phenylaniline in soil is estimated to be 75.0 days (1800 hrs). Based on this half-life value of test chemical 4-methoxy-2-methyl-N-phenylaniline, it is concluded that the chemical is not persistent in the soil environment and the exposure risk to soil dwelling animals is low .