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Biodegradation in water

Biodegradability of 3-Nitroacetophenone (CAS no. 121 -89 -1) is predicted using QSAR toolbox version 3.4 (2017). Test substance undergoes 22.75% degradation by CO2 evolution parameter in 28 days. Thus, based on percentage degradation, the test chemical 3-Nitroacetophenone was estimated to be not 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-Nitroacetophenone (CAS No. 121 -89 -1). If released in to the environment, 19.8% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of 3-Nitroacetophenone 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 moderate to low whereas the half-life period of 3-Nitroacetophenone 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 0.114%), indicates that 3-Nitroacetophenone is not persistent in sediment.

Biodegradation in soil

The half-life period of 3-Nitroacetophenone (CAS No. 121 -89-1) 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, 79.4% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of 3-Nitroacetophenone in soil is estimated to be 75 days (1800 hrs). Based on this half-life value of 3-Nitroacetophenone, 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

In different studies, 3 -Nitroacetophenone (CAS No. 121 -89 -1) has been investigated for potential for biodegradation to a greater or lesser extent. These include 2 predicted data for the target compound 3 -Nitroacetophenone and the 6 studies (from peer reviewed journal, authoritative database and secondary source) for its closest read across substance with logKow as the primary descriptor.

 

Prediction of the biodegradability of test substance 3-Nitroacetophenone (CAS no. 121 -89 -1) was done by SSS (2017) using OECD QSAR toolbox version 3.4with logKow as the primary descriptor(2017). Test substance undergoes 22.75% degradation by CO2 evolution parameter in 28 days. Thus, based on percentage degradation, the test chemical 3-Nitroacetophenone was estimated to be not readily biodegradable in water.

 

Another prediction was done using the Estimation Programs Interface Suite (EPI suite, 2017) for estimating the biodegradation potential of the test compound 3-Nitroacetophenone (CAS no. 121 -89 -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 as Biowin 1-7, respectively) of the BIOWIN v4.10 software. The results indicate that 3-Nitroacetophenone is expected to be not readily biodegradable.

 

In a weight of evidence study of read across substance 3-Nitrobenzoic acid (CAS no. 121-92-6) which is having a percentage similarity of 80-90% with the target chemical 3-Nitroacetophenone (J-CHECK, 2016), biodegradation experiment was conducted for 14 days for evaluating the percentage biodegradability of read across substance 3-Nitrobenzoic acid (CAS no. 121-92-6). 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 read across substance was determined to 6, 0 and 3% by BOD, TOC removal and UV-Vis parameter in 14 days. Thus, based on percentage degradation, 3-Nitrobenzoic acid is considered to be not readily biodegradable in nature.

 

For the same read across substance 3-Nitrobenzoic acid (CAS no. 121-92-6) which is having a percentage similarity of 80-90% with the target chemical 3-Nitroacetophenone, biodegradation experiment was conducted by Takashi Kameya, et. al; 1995; for 28 days for evaluating the percentage biodegradability of read across substance 3 -Nitrobenzoic acid (CAS no. 121-92-6). Seeding bacteria was used as a test inoculum. The seeding bacteria had been cultured in a continuous anaerobic bioreactor at 37 + 1°C.Synthetic sewage, composed of glucose, peptone and corn steap liquor (carbon ratio = 1:1:2), is supplied into the reactor (3.0 g-C/l, 8.0 g-CS./.d). In this culture, > 95% acidic decomposition and > 90% methanogenic decomposition are achieved.

A standard test and low conc. tests using 50 ml vials (total capacity: 68 ml) was employed. Ten test vials were prepared under the same conditions, and they were set in a water bath at 37°C ± 0.5”C. The original solution was added to the test inoculum and organic medium in oxygen-free water. At the starting time and after every week, two vials were opened simultaneously, and the concentration of organic compound was analyzed. The concentration of organic compound was determined by dissolved organic carbon (DOC) in the standard test and by chromatography in low conc. test. Biodegradation ratio is determined by analysing the decrease of DOC in the standard test. The percentage degradation of the read across compound was determined to be < 30% degradation by DOC removal, chromatography in 28 days by using standard test Thus, based on the percentage degradation, the read across chemical 3-Nitrobenzoic acid was considered to be not readily biodegradable in nature.

 

In a weight of evidence study (J-CHECK, 2016) of another read across substance Tripropylene glycol (CAS no. 24800-44-0), biodegradation was conducted for 28 days for evaluating the percentage biodegradability of read across substance Tripropylene glycol (CAS no. 24800-44-0). 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 read across substance was determined to be 2, 0 and 2% by BOD, TOC removal and GC parameter in 28 days. Thus, based on percentage degradation, Tripropylene glycol is considered to be not readily biodegradable in nature.

 

Another weight of evidence study (HSDB, 2016) of biodegradation was conducted for 20 days for evaluating the percentage biodegradability of read across substance Dipropylene glycol monomethyl ether (CAS no. 34590-94-8). The percentage degradation of read across substance was determined to 0, 0 and 31% degradation by ThOD parameter in 5, 10 and 20 days, respectively. Thus, based on percentage degradation, Dipropylene glycol monomethyl ether was considered to be not readily biodegradable in nature.

 

Weight of evidence study (OECD SIDS, 2001) of biodegradation for read across substance Dipropylene glycol monomethyl ether (CAS no. 34590-94-8) was conducted for 28 days for evaluating the percentage biodegradability of chemical Dipropylene glycol monomethyl ether. Initial test substance conc. used in the study was10 mg/l, respectively. The percentage degradation of read across substance was determined to be 34% degradation in 28 days. At a concentration of 20 mg/l degradation was <10% after 28 days. Thus, based on percentage degradation, Dipropylene glycol monomethyl ether was considered to be not readily biodegradable in nature.

 

In an additional weight of evidence study (OECD SIDS, 2003), biodegradation was conducted for 28 days for evaluating the percentage biodegradability of read across substance Dipropylene glycol monobutyl ether (CAS no. 29911-28-2). The study was performed according to OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test). Initial test substance conc. used in the study was 0, 1.86, or 9.29 mg/l, respectively. Domestic sewage was used as a test inoculum collected from a local municipal sewage treatment facility. To test for its ready biodegradability potential, read across chemical was incubated for 28 days in continuously agitated closed bottles in the dark at two concentrations with inoculum (secondary effluent) collected from a local municipal sewage treatment facility. The incubation temperature of the water was 19.7-20.0°C, pH ranged from 7.2 to 7.4, hardness was not reported, and the concentration of inoculum was one droplet per liter of test solution. Oxygen concentration was the measured variable. Degradation of read across chemical was monitored by assessing the dissipation of oxygen in the test solution over time (i.e., measuring dissolved oxygen content with an oxygen electrode at various time points). Oxygen content was measured (in duplicate bottles) on days 0, 5, 15, and 28. Degradation was calculated by dividing the biochemical oxygen demand (BOD) expressed as mg O2 per mg DPnB, by the theoretical oxygen demand (ThOD).The percentage degradation of read across substance was determined to be 0% by %ThOD parameter in 28 days. Thus, based on percentage degradation, Dipropylene glycol monobutyl ether was considered to be not readily biodegradable in water.

 

On the basis of above results for target and read across substance, it can be concluded that the test substance 3 -Nitroacetophenone can be expected to be not 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-Nitroacetophenone (CAS No. 121 -89 -1). If released in to the environment, 19.8% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of 3-Nitroacetophenone 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 moderate to low whereas the half-life period of 3-Nitroacetophenone 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 0.114%), indicates that 3-Nitroacetophenone is not persistent in sediment.

Biodegradation in soil

The half-life period of 3-Nitroacetophenone (CAS No. 121 -89-1) 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, 79.4% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of 3-Nitroacetophenone in soil is estimated to be 75 days (1800 hrs). Based on this half-life value of 3-Nitroacetophenone, 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-Nitroacetophenone can be considered to be not readily biodegradable in nature.