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Biodegradation in water

Biodegradability of 2-[(E)-2-(4-chloro-2-nitrophenyl)diazen-1-yl]-N-(4-ethoxyphenyl)-3-oxobutanamide (CAS no. 52320 -66 -8) is predicted using QSAR toolbox version 3.3 (2017) with logKow as the primary descriptor. Test substance undergoes 5.3% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical 2 -[(E)-2 -(4 -chloro-2 -nitrophenyl)diazen-1 -yl]-N-(4 -ethoxyphenyl)-3 -oxobutanamide was estimated to be not readily biodegradable in water.

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Biodegradation in water

Various predicted data for the target compound 2-[(E)-2-(4-chloro-2-nitrophenyl)diazen-1-yl]-N-(4-ethoxyphenyl)-3-oxobutanamide(CAS No. 52320-66-8) 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 a prediction done by SSS (2017) using OECD QSAR toolbox version 3.3 with logKow as the primary descriptor, percentage biodegradability of test chemical 2 -[(E)-2 -(4 -chloro-2 -nitrophenyl)diazen-1 -yl]-N-(4-ethoxyphenyl)-3-oxobutanamide(CAS No. 52320-66-8) was estimated.Test substance undergoes 5.3% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical2-[(E)-2-(4-chloro-2-nitrophenyl)diazen-1-yl]-N-(4-ethoxyphenyl)-3-oxobutanamidewas estimated to be not readily biodegradable in water.

 

In another prediction using the Estimation Programs Interface Suite (EPI suite, 2017), the biodegradation potential of the test compound 2 -[(E)-2 -(4 -chloro-2 -nitrophenyl)diazen-1 -yl]-N-(4 -ethoxyphenyl)-3 -oxobutanamide(CAS No. 52320-66-8) 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 chemical 2 -[(E)-2 -(4 -chloro-2 -nitrophenyl)diazen-1 -yl]-N-(4 -ethoxyphenyl)-3-oxobutanamideis expected to be not readily biodegradable.

 

In a supporting weight of evidence study from authoritative database (J-CHECK & HSDB, 2017 and EnviChem, 2014) for the read across chemical 2,2'-[(3,3'-dichlorobiphenyl-4,4'-diyl) didiazene-2,1 -diyl]bis(3 -oxo-N-phenylbutanamide) (CAS no. 6358-85-6),biodegradation experiment was conducted for 14 days for evaluating the percentage biodegradability of read across substance 2,2'-[(3,3'-dichlorobiphenyl-4,4'-diyl)didiazene-2,1 -diyl]bis(3 -oxo-N-phenylbutanamide). The study was performed according to OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I)). 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 substance 2,2'-[(3,3'-dichlorobiphenyl- 4,4'-diyl)didiazene-2,1 -diyl]bis(3 -oxo-N-phenylbutanamide) was determined to be 0% by BOD parameter in 14 days. Thus, based on percentage degradation, 2,2'-[(3,3'-dichloro biphenyl-4,4'-diyl)didiazene-2,1 -diyl]bis(3 -oxo-N-phenylbutanamide) is considered to be not readily biodegradable in nature.

 

Another biodegradation study was conducted for 14 days for evaluating the percentage biodegradability of test substance 2,2'-[(3,3'-dichlorobiphenyl-4,4'-diyl)didiazene-2,1 -diyl]bis(3 -oxo-N-phenylbutanamide) (CAS no. 6358-85-6) (OECD SIDS, 2003). The study was performed according to OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I)) under aerobic conditions at a temperature of 25°C. 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 substance 2,2'-[(3,3'-dichlorobiphenyl-4,4'-diyl)didiazene-2,1 -diyl]bis(3 -oxo-N-phenylbutanamide) was determined to be 0% by BOD and UV-Vis parameter in 14 days. Thus, based on percentage degradation, 2,2'-[(3,3'-dichlorobiphenyl-4,4'-diyl)didiazene-2,1-diyl]bis(3-oxo-N-phenylbutanamide) is considered to be not readily biodegradable in nature.

 

On the basis of above results for target chemical2-[(E)-2-(4-chloro-2-nitrophenyl)diazen-1-yl]-N-(4-ethoxyphenyl)-3-oxobutanamide(from OECD QSAR toolbox version 3.3 and EPI suite, 2017) and for its read across substance (from authoritative database J-CHECK, HSDB & EnviChem and secondary source OECD SIDS), it can be concluded that the test substance 2-[(E)-2-(4-chloro-2-nitrophenyl)diazen-1-yl]-N-(4-ethoxyphenyl)-3-oxobutanamidecan be expected to be not readily biodegradable in nature.