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Biodegradation in water

Biodegradation study was conducted according to CO2 generation amount method for evaluating the percentage biodegradability of test substance 2 -hydroxy-1H-isoindole-1,3(2H)-dione (CAS no. 524 -38 -9) (Scifinder, American Chemical Society, 2017).The final aerobic percentage degradation rate of test substance was determined to be 95.80% degradation by CO2 evolution parameter in a 14 day period. Thus, based on percentage degradation, 2 -hydroxy-1H-isoindole-1,3(2H)-dione is considered 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 2 -hydroxy-1H-isoindole-1,3(2H)-dione (CAS No. 524 -38 -9). If released in to the environment, 30.7% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of 2 -hydroxy-1H-isoindole-1,3(2H)-dione in water is estimated to be 15 days (360 hrs). The half-life (15 days estimated by EPI suite) indicates that the 2 -hydroxy-1H-isoindole-1,3(2H)-dione is not persistent in water and the exposure risk to aquatic animals is moderate to low whereas the half-life period of 2 -hydroxy-1H-isoindole-1,3(2H)-dione in sediment is estimated to be 135 days (3240 hrs). However, as the percentage release of 2 -hydroxy-1H-isoindole-1,3(2H)-dione into the sediment is less than 1% (i.e, reported as 0.0691%), indicates that 2 -hydroxy-1H-isoindole-1,3(2H)-dione is not persistent in sediment.

Biodegradation in soil

The half-life period of test chemical2-hydroxy-1H-isoindole-1,3(2H)-dione(CAS No. 524-38-9) 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, 69.2% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of2-hydroxy-1H-isoindole-1,3(2H)-dionein soil is estimated to be 30 days (720 hrs). Based on this half-life value of2-hydroxy-1H-isoindole-1,3(2H)-dione, 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 study and predicted data for the target compound 2-hydroxy-1H-isoindole-1,3(2H)-dione (CAS No. 524-38-9) and various supporting studies for its read across substance were reviewed for the biodegradation end point which are summarized as below:

 

In an experimental key study, biodegradation experiment was conducted according to CO2 generation amount method for evaluating the percentage biodegradability of test substance 2 -hydroxy-1H-isoindole-1,3(2H)-dione (CAS no. 524 -38 -9) (Scifinder, American Chemical Society, 2017). The final aerobic percentage degradation rate of test substance was determined to be 95.80% degradation by CO2 evolution parameter in a 14 day period. Thus, based on percentage degradation, 2 -hydroxy-1H-isoindole-1,3(2H)-dione is considered to be readily biodegradable in nature.

 

In a supporting study from secondary source (Scifinder, American Chemical Society, 2017), biodegradation experiment was performed according to the shaking cultivation method for evaluating the percentage biodegradability of test substance 2 -hydroxy-1H-isoindole-1,3(2H)-dione (CAS no. 524 -38 -9). The primary aerobic percentage degradation rate of test substance was determined to be 93.60% degradation in a 5 day period. Thus, based on percentage degradation, 2 -hydroxy-1H-isoindole-1,3(2H)-dione is considered to be readily biodegradable in nature.

 

For target chemical 2-hydroxy-1H-isoindole-1,3(2H)-dione(CAS No. 524-38-9), biodegradability of2-hydroxy-1H-isoindole-1,3(2H)-dioneis predicted using OECD QSAR toolbox version 3.4 with logKow as the primary descriptor (2017).Test substance undergoes 73.63% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical 2-hydroxy-1H-iso indole-1,3(2H)-dione was estimated to be readily biodegradable in water.

 

In a supporting study from authoritative database (J-CHECK, 2016), biodegradation experiment was conducted for 14 days for evaluating the percentage biodegradability of read across substance1H-isoindole-1,3(2H)-dione(CAS no. 85 -41 -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 be 92, 94 and 100% by BOD(NH3), TOC removal and HPLC parameter in 14 days. Thus, based on percentage degradation, 1H-isoindole-1,3(2H)-dione is considered to be readily biodegradable in nature.

 

For another read across chemical 2 -bentzofuran-1,3 -dione (CAS no. 85 -44 -9),biodegradation study was conducted for 14 days for evaluating the percentage biodegradability of read across substance 2 -bentzofuran-1,3 –dione(J-CHECK, 2016). 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 85.2, 93 and 96.4% degradation by BOD, TOC removal and UV-Vis parameter in 14 days. Thus, based on percentage degradation, 2 -bentzofuran-1,3 -dione is considered to be readily biodegradable in nature.

 

Another biodegradation study for the same read across substance 2 -bentzofuran-1,3 -dione (CAS no. 85 -44 -9) was conducted for 30 days for evaluating the percentage biodegradability of substance 2 -bentzofuran-1,3 -dione(HSDB and OECD SIDS, 2016). The study was performed according to OECD Guideline 301 D “Ready Biodegradability: Closed Bottle Test”. Concentration of inoculum i.e, sludge used was 3 mg/l and initial test substance conc. used in the study was 1000 mg/l, respectively. The percentage degradation of read across substance was determined to be 45, 58 and 71% by BOD parameter after 5, 10 and 30 days, respectively. Thus, based on percentage degradation, 2 -bentzofuran-1,3 -dione is considered to be readily biodegradable in nature.

 

On the basis of above results for target chemical 2-hydroxy-1H-isoindole-1,3(2H)-dione (from secondary source Scifinderand OECD QSAR toolbox version 3.4, 2017) and for its read across substance (from authoritative database J-CHECK, HSDB and secondary source OECD SIDS, 2016), it can be concluded that the test substance2-hydroxy-1H-isoindole-1,3(2H)-dionecan 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 2 -hydroxy-1H-isoindole-1,3(2H)-dione (CAS No. 524 -38 -9). If released in to the environment, 30.7% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of 2 -hydroxy-1H-isoindole-1,3(2H)-dione in water is estimated to be 15 days (360 hrs). The half-life (15 days estimated by EPI suite) indicates that the 2 -hydroxy-1H-isoindole-1,3(2H)-dione is not persistent in water and the exposure risk to aquatic animals is moderate to low whereas the half-life period of 2 -hydroxy-1H-isoindole-1,3(2H)-dione in sediment is estimated to be 135 days (3240 hrs). However, as the percentage release of 2 -hydroxy-1H-isoindole-1,3(2H)-dione into the sediment is less than 1% (i.e, reported as 0.0691%), indicates that 2 -hydroxy-1H-isoindole-1,3(2H)-dione is not persistent in sediment.

Biodegradation in soil

The half-life period of test chemical2-hydroxy-1H-isoindole-1,3(2H)-dione(CAS No. 524-38-9) 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, 69.2% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of2-hydroxy-1H-isoindole-1,3(2H)-dionein soil is estimated to be 30 days (720 hrs). Based on this half-life value of2-hydroxy-1H-isoindole-1,3(2H)-dione, 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 2-hydroxy-1H-isoindole-1,3(2H)-dione can be considered to bereadily biodegradable in nature.