Dibenzo[b,f]cyclohepten-1-one

Endpoint summary

Description of key information

Biodegradation in water

Biodegradability of 1H-dibenzo[a,d][7]annulen-1-one ispredicted using QSAR toolbox version 3.4 with logKow as the primary descriptor (2017). Test substance undergoes 11.05% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical 1H-dibenzo[a,d][7]annulen-1-one 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  1H-dibenzo[a,d][7]annulen-1-one (CAS No. 2222 -33 -5). If released in to the environment, 17.1% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of 1H-dibenzo[a,d][7]annulen-1-one 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 1H-dibenzo[a,d][7]annulen-1-one in sediment is estimated to be 337.5 days (8100 hrs). Based on this this half-life value of test chemical, it indicates that 1H-dibenzo[a,d][7]annulen-1-one is persistent in sediment.

 

Biodegradation in soil

The half-life period of 1H-dibenzo[a,d][7]annulen-1-one (CAS No. 2222 -33 -5) 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, 79.3 % of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of 1H-dibenzo[a,d][7]annulen-1-one in soil is estimated to be 75 days (1800 hrs). Based on this half-life value of 1H-dibenzo[a,d][7]annulen-1 -one, 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.

Bioaccumulation: aquatic / sediment:

From BCFBAF Program (v3.00) model of EPI suite the estimated bio concentration factor (BCF) for 1H-dibenzo[a,d][7]annulen-1-one is 85.28 L/kg wet-wt which does not exceed the bioconcentration threshold of 2000.Thus it is concluded that 1H-dibenzo[a,d][7]annulen-1-one is not expected to bio accumulate in the food chain.

Adsorption / desorption:

The adsorption coefficient Koc in soil and in sewage sludge Dibenzo[b,f]cyclohepten-1-one(CAS No.2222-33 -5) was determined by the Reverse Phase High Performance Liquid Chromatographic method according to OECD Guideline No. 121 for testing of Chemicals. The reference substances were chosen according to estimated Koc range of the test substance and generalized calibration graph was prepared. The reference substances were having Koc value ranging from 1.25 to 4.09. The Log Koc value was found to be 3.0677±

0.0003at 25°C.

Additional information

Biodegradation in water

2 predicted data for the target compound 1H-dibenzo[a,d][7]annulen-1-one (CAS no. 2222-33-5) and the total 3 weight of evidence studies (from authoritative database) for its closest structurally similar read across substance with logKow as the primary descriptor were reviewed for the biodegradation end point which are summarized as below:

 

In a predicted data done by using QSAR toolbox version 3.4 with logKow as the primary descriptor (2017), percentage biodegradability of test chemical 1H-dibenzo[a,d][7]annulen-1-one (CAS no. 2222-33-5) was estimated. Test substance undergoes 11.05% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical 1H-dibenzo[a,d][7]annulen-1-one was estimated to be not readily biodegradable in water.

 

In another prediction done by using the Estimation Programs Interface Suite (EPI suite, 2017), the biodegradation potential of the test compound  1H-dibenzo[a,d][7]annulen-1 -one (CAS no. 2222 -33 -5) 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 1H-dibenzo[a,d][7]annulen-1-one is expected to be not readily biodegradable.

 

In a weight of evidence study fromauthoritative database(J-CHECK, 2016) for read across substance Benzanthrone (CAS no. 82 -05 -3),biodegradation experiment was conducted for 28 days for evaluating the percentage biodegradability of read across substance Benzanthrone. 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 0 and 1% by BOD and HPLC parameter in 28 days. Thus, based on percentage degradation, Benzanthrone is considered to be not readily biodegradable in nature.

 

Another supporting weight of evidence study of biodegradation was conducted for 28 days for evaluating the percentage biodegradability of read across substance 1-Hydroxy-9,10-anthraquinone (CAS no. 129 -43 -1) (J-CHECK). 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 and 1% by BOD and HPLC parameter in 28 days. Thus, based on percentage degradation,1 -Hydroxy-9,10 -anthraquinone is considered to be not readily biodegradable in nature.

 

In an additional weight of evidence study of read across substanceTetraphene-7, 12-dione (CAS no. 2498 -66 -0)from authoritative database (J-CHECK, 2016),biodegradation experiment was carried out for 28 days for evaluating the percentage biodegradability of read across substanceTetraphene-7, 12-dione. 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 1 and 3% by BOD and HPLC parameter in 28 days. Thus, based on percentage degradation, Tetraphene-7, 12 -dione is considered to be not readily biodegradable in nature.

 

On the basis of above results for target chemical1H-dibenzo[a,d][7]annulen-1-one (from OECD QSAR toolbox version 3.4 and EPI Suite) and for its read across substance (from authoritative database J-CHECK), it can be concluded that the test substance 1H-dibenzo[a,d][7]annulen-1-one 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  1H-dibenzo[a,d][7]annulen-1-one (CAS No. 2222 -33 -5). If released in to the environment, 17.1% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of 1H-dibenzo[a,d][7]annulen-1-one 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 1H-dibenzo[a,d][7]annulen-1-one in sediment is estimated to be 337.5 days (8100 hrs). Based on this this half-life value of test chemical, it indicates that 1H-dibenzo[a,d][7]annulen-1-one is persistent in sediment.

 

Biodegradation in soil

The half-life period of 1H-dibenzo[a,d][7]annulen-1-one (CAS No. 2222 -33 -5) 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, 79.3 % of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of 1H-dibenzo[a,d][7]annulen-1-one in soil is estimated to be 75 days (1800 hrs). Based on this half-life value of 1H-dibenzo[a,d][7]annulen-1 -one, 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 substance1H-dibenzo[a,d][7]annulen-1-one can be considered to be not readily biodegradable in nature.

Bioaccumulation: aquatic / sediment:

Four different validated predicted models estimate the bioaccumulation in aquatic endpoint for target chemical 1H-dibenzo[a,d][7]annulen-1-one (Cas no. 2222-33-5) which are summarized as followed:

First model from BCFBAF Program (v3.00) model of EPI suite the estimated bio concentration factor (BCF) for 1H-dibenzo[a,d][7]annulen-1-one is 85.28 L/kg wet-wt which does not exceed the bioconcentration threshold of 2000.Thus it is concluded that 1H-dibenzo[a,d][7]annulen-1-one is not expected to bio accumulate in the food chain.

Another prediction done by PBT profiler which indicate the Bioaccumulation factor (BCF) was predicted to be 85 L/kg wet-wt at 25 deg.C. Based on the BCF concentration it is concluded that the test chemical 1H-dibenzo[a,d][7]annulen-1-one is non bioaccumulative in nature as it does not exceed the BCF criteria of 2000.

Also Scifinder database suggest the Bioconcentration factor (BCF) for target chemical 1H-dibenzo[a,d][7]annulen-1-one was predicted to be 261 at pH 1-10 and temperature 25 deg.C.

 

And Chemspider - ACD/PhysChem Suite predicted model indicate Bioconcentration factor (BCF) for target chemical 1H-dibenzo[a,d][7]annulen-1-one was predicted to be 110.21 at pH 5.5 and 7.4 at temperature 25 deg.C.

All predicted values for bioaccumulation is in the range of 85-261(L/kg or dimensionless) conclude the target chemical 1H-dibenzo[a,d][7]annulen-1-one (Cas no. 2222-33-5) is non bioaccumulative in aquatic environment as it does not exceed the BCF criteria of 2000 as per the CLP regulation.

Adsorption / desorption:

Four studies including experimental report and different validated prediction models data to estimate the adsorption in soil/sediment for target chemical 1H-dibenzo[a,d][7]annulen-1-one (Cas no. 2222-33-5). The information is summarized as follows:

First key study from experimental report by UERL laboratory; 2017 suggest the adsorption coefficient Koc in soil and in sewage sludge Dibenzo[b,f]cyclohepten-1-one(CAS No.2222-33 -5) was determined by the Reverse Phase High Performance Liquid Chromatographic method according to OECD Guideline No. 121 for testing of Chemicals. The reference substances were chosen according to estimated Koc range of the test substance and generalized calibration graph was prepared. The reference substances were having Koc value ranging from 1.25 to 4.09. The Log Koc value was found to be 3.0677± 0.0003at 25°C.

Above result supported by estimation model KOCWIN (v2.00) from EPI suite estimated the Soil Adsorption Coefficient i.e Koc value of 1H-dibenzo[a,d][7]annulen-1-one as 3701 L/kg (log Koc = 3.56) by means of MCI method at 25 deg.C. This Koc value indicates that the substance 1H-dibenzo[a,d][7]annulen-1-one has a Strong sorption to soil and sediment and therefore have negligible migration potential to groundwater.  

 

Another prediction done by Chemspider - ACD/PhysChem Suite which indicate the soil adsorption coefficient i.e Koc value of test substance 1H-dibenzo[a,d][7]annulen-1-one was estimated to be 1007.95(log koc-3.003) at pH 5.5 and pH 7.4 and temp.25 deg.C.Koc values at different pH indicates that the substance 1H-dibenzo[a,d][7]annulen-1-one has Moderate sorption to soil and sediment and therefore have slow migration potential to groundwater.

 

And from Scifinder database the soil adsorption coefficient i.e Koc value of test substance 1H-dibenzo[a,d][7]annulen-1-one was estimated to be 1870 (Log koc-3.27) at pH 1-10 and temperature 25 deg.C. This Koc value at all range of pH condition indicates that the substance 1H-dibenzo[a,d][7]annulen-1-one has moderate sorption to soil and sediment and therefore have slow migration potential to groundwater.

 

All available values for adsorption (log KOC) is in the range of 3.003-3.56 (L/kg or dimensionless) gives common conclusion as the target chemical 1H-dibenzo[a,d][7]annulen-1-one (Cas no. 2222-33-5) has slow to negligible mobility in soil/sediment.