Disodium 2-(2,4,5,7-tetraiodo-6-oxido-3-oxoxanthen-9-yl)benzoate

Endpoint summary

Description of key information

Hydrolysis:

Test chemical is not expected to undergo hydrolysis in the environment due to the lack of functional groups that hydrolyze under environmental conditions.

 

Biodegradation in water:

28-days Manometric respirometry test was conducted following the OECD guideline 301F to determine the ready biodegradability of the test chemical. The study was performed at a temperature of 20 ± 1°C. Mixture of domestic waste water, surface soil and soil samples was used as a test inoculum for the study. This inoculum was collected and were mixed to get diluted suspension. The inoculum was kept aerobic until being used for experiment by supplying organic and inorganic sources required by micro flora to sustain at controlled laboratory conditions. This gave the bacterial count as 107to 108 CFU/ml. At the regular interval microbial plating was also performed on agar to confirm the vitality and CFU count of microorganism. OECD mineral medium was used for the study. The test system included control, test item and reference item. The concentration of test and reference item (Sodium Benzoate) chosen for both the study was 100mg/L, while that of inoculum was 10ml/l. ThOD (Theoretical oxygen demand) of test and reference item was determined by calculation. % Degradation was calculated using the values of BOD and ThOD for test chemical and reference chemical. The % degradation of procedure control (reference item) was also calculated using BOD & ThOD and was found to be 77.36%. The mean BOD values (mg O2/l) in control on 28th day was 28.2 mg O2/l, thereby fulfilling the control validity criteria (i.e., the oxygen consumption of the inoculum blank is normally 20-30 mg O2/l and should not be greater than 60 mg/l in 28 days). Degradation of Sodium Benzoate exceeds 60% after 14 days. The activity of the inoculums is thus verified and the test can be considered as valid. The BOD28 value of test chemical was observed to be 0.058 mgO2/mg. ThOD was calculated as 0.709 mgO2/mg. Accordingly, the % degradation of the test chemical after 28 days of incubation at 20 ± 1°C according to manometric respirometry test was determined to be 8.18%. Thus, the test chemical can be considered as not readily biodegradable.

Biodegradation in water: Simulation test:

Estimation Programs Interface prediction model was run to predict the half-life in water for the test chemical. If released in to the environment, 4.74 % 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 180 days (4320 hrs). The half-life 180 days estimated by EPI suite indicates that the chemical is persistent in water and the exposure risk to aquatic animals is moderate to high.

 

Biodegradation in sediment: Simulation test:

Estimation Programs Interface prediction model was run to predict the half-life in sediment for the test chemical. If released in to the environment, 9.39 % of the chemical will partition into sediment according to the Mackay fugacity model level III and the half-life period of test chemical in sediment is estimated to be 1620.8 days (38900 hrs). The half-life 1620.8 days estimated by EPI suite indicates that the chemical is persistent in sediment and the exposure risk to aquatic animals is moderate to high.

 

Biodegradation in soil:

The half-life period of test chemical in soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database (EPI suite). If released into the environment, 85.8 % of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of test chemical in soil is estimated to be 360 days (8640 hrs). Based on this half-life value of test chemical, it is concluded that the chemical is persistent in the soil environment and the exposure risk to soil dwelling animals is moderate to high.

 

Bioaccumulation: aquatic / sediment:

Using BCFBAF Program (v3.00) model of EPI suite, the estimated bio concentration factor (BCF) for test chemical was 56.23 L/kg wet-wt at 25 °C, which does not exceed the bioconcentration threshold of 2000. Therefore it is concluded that test chemical is non-bioaccumulative in food chain.

 

Adsorption:

The adsorption coefficient Koc in soil and in sewage sludge of test chemical was determined by the Reverse Phase High Performance Liquid Chromatographic method according to OECD Guideline No. 121 for testing of Chemicals. The solutions of the test substance and reference substances were prepared in appropriate solvents. A test chemical solution was prepared by accurately weighing 50mg of test chemical and diluted with mobile phase up to 100ml. Thus, the test solution concentration was 500mg/l. The pH of test substance was 7.681. Each of the reference substance and test substance were analysed by HPLC at 210 nm. After equilibration of the HPLC system, Urea was injected first, the reference substances were injected in duplicate, followed by the test chemical solution in duplicate. Reference substances were injected again after test sample, no change in retention time of reference substances was observed. Retention time tR were measured, averaged and the decimal logarithms of the capacity factors k were calculated. The graph was plotted between log Koc versus log k. The linear regression parameter of the relationship log Koc vs log k were also calculated from the data obtained with calibration samples and therewith, log Koc of the test substance was determined from its measured capacity factor. The reference substances Urea, Benzamide, N-methylbenzamide, 4-Nitrobenzamide, N,N-dimethylbenzamide, 4-methylaniline(p-Tolouidine), 4-chloroaniline, N-methylaniline, Nitrobenzene, 2 - nitrophenol, phenanthrene, were chosen having Koc value range from 1.239 to 4.09. The Log Koc value of test chemical was determined to be 1.291± 0.051 dimensionless at 25°C. This log Koc value indicates that the substance has a negligible sorption to soil and sediment and therefore have rapid migration potential to ground water.

Additional information

Hydrolysis:

Test chemical is not expected to undergo hydrolysis in the environment due to the lack of functional groups that hydrolyze under environmental conditions.

 

Biodegradation in water:

28-days Manometric respirometry test was conducted following the OECD guideline 301F to determine the ready biodegradability of the test chemical. The study was performed at a temperature of 20 ± 1°C. Mixture of domestic waste water, surface soil and soil samples was used as a test inoculum for the study. This inoculum was collected and were mixed to get diluted suspension. The inoculum was kept aerobic until being used for experiment by supplying organic and inorganic sources required by micro flora to sustain at controlled laboratory conditions. This gave the bacterial count as 107to 108 CFU/ml. At the regular interval microbial plating was also performed on agar to confirm the vitality and CFU count of microorganism. OECD mineral medium was used for the study. The test system included control, test item and reference item. The concentration of test and reference item (Sodium Benzoate) chosen for both the study was 100mg/L, while that of inoculum was 10ml/l. ThOD (Theoretical oxygen demand) of test and reference item was determined by calculation. % Degradation was calculated using the values of BOD and ThOD for test chemical and reference chemical. The % degradation of procedure control (reference item) was also calculated using BOD & ThOD and was found to be 77.36%. The mean BOD values (mg O2/l) in control on 28th day was 28.2 mg O2/l, thereby fulfilling the control validity criteria (i.e., the oxygen consumption of the inoculum blank is normally 20-30 mg O2/l and should not be greater than 60 mg/l in 28 days). Degradation of Sodium Benzoate exceeds 60% after 14 days. The activity of the inoculums is thus verified and the test can be considered as valid. The BOD28 value of test chemical was observed to be 0.058 mgO2/mg. ThOD was calculated as 0.709 mgO2/mg. Accordingly, the % degradation of the test chemical after 28 days of incubation at 20 ± 1°C according to manometric respirometry test was determined to be 8.18%. Thus, the test chemical can be considered as not readily biodegradable.

Biodegradation in water: Simulation test:

Estimation Programs Interface prediction model was run to predict the half-life in water for the test chemical. If released in to the environment, 4.74 % 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 180 days (4320 hrs). The half-life 180 days estimated by EPI suite indicates that the chemical is persistent in water and the exposure risk to aquatic animals is moderate to high.

 

Biodegradation in sediment: Simulation test:

Estimation Programs Interface prediction model was run to predict the half-life in sediment for the test chemical. If released in to the environment, 9.39 % of the chemical will partition into sediment according to the Mackay fugacity model level III and the half-life period of test chemical in sediment is estimated to be 1620.8 days (38900 hrs). The half-life 1620.8 days estimated by EPI suite indicates that the chemical is persistent in sediment and the exposure risk to aquatic animals is moderate to high.

 

Biodegradation in soil:

The half-life period of test chemical in soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database (EPI suite). If released into the environment, 85.8 % of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of test chemical in soil is estimated to be 360 days (8640 hrs). Based on this half-life value of test chemical, it is concluded that the chemical is persistent in the soil environment and the exposure risk to soil dwelling animals is moderate to high.

 

Bioaccumulation: aquatic / sediment:

Using BCFBAF Program (v3.00) model of EPI suite, the estimated bio concentration factor (BCF) for test chemical was 56.23 L/kg wet-wt at 25 °C, which does not exceed the bioconcentration threshold of 2000. Therefore it is concluded that test chemical is non-bioaccumulative in food chain.

 

Adsorption:

The adsorption coefficient Koc in soil and in sewage sludge of test chemical was determined by the Reverse Phase High Performance Liquid Chromatographic method according to OECD Guideline No. 121 for testing of Chemicals. The solutions of the test substance and reference substances were prepared in appropriate solvents. A test chemical solution was prepared by accurately weighing 50mg of test chemical and diluted with mobile phase up to 100ml. Thus, the test solution concentration was 500mg/l. The pH of test substance was 7.681. Each of the reference substance and test substance were analysed by HPLC at 210 nm. After equilibration of the HPLC system, Urea was injected first, the reference substances were injected in duplicate, followed by the test chemical solution in duplicate. Reference substances were injected again after test sample, no change in retention time of reference substances was observed. Retention time tR were measured, averaged and the decimal logarithms of the capacity factors k were calculated. The graph was plotted between log Koc versus log k. The linear regression parameter of the relationship log Koc vs log k were also calculated from the data obtained with calibration samples and therewith, log Koc of the test substance was determined from its measured capacity factor. The reference substances Urea, Benzamide, N-methylbenzamide, 4-Nitrobenzamide, N,N-dimethylbenzamide, 4-methylaniline(p-Tolouidine), 4-chloroaniline, N-methylaniline, Nitrobenzene, 2 - nitrophenol, phenanthrene, were chosen having Koc value range from 1.239 to 4.09. The Log Koc value of test chemical was determined to be 1.291± 0.051 dimensionless at 25°C. This log Koc value indicates that the substance has a negligible sorption to soil and sediment and therefore have rapid migration potential to ground water.