Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Hydrolysis

In accordance with column 2 of Annex VIII of the REACH regulation, testing for this endpoint is technically not feasible and does not need to be conducted since the test chemical is insoluble in water.

Biodegradation in water

28-days Manometric respirometry test following the OECD guideline 301F to determine the ready biodegradability of the test chemical (Experimental study report, 2015). 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 100 mg/L, while that of inoculum was 10 ml/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 item and reference item. The % degradation of procedure control (Sodium Benzoate) was also calculated using BOD & ThOD and was determined to be 79.36%. The DO depletion(mg O2/l) in inoculum blank on 28th day was 24.2 mg O2/l which fulfilled the validity criteria (i.e., The DO depletion of the inoculums blank is normally 20-30 mg O2/l and should not be greater than 60 mg/l in 28 days) for inoculum blank (control). Degradation of Sodium acetate exceeds 64% after 4 days. Thus the activity of the inoculums is verified and the test is considered as valid.The BOD28 value of test chemical was observed to be 0.026 mgO2/mg. ThOD was calculated as 3.045 mgO2/mg. Accordingly, the % degradation of the test item after 28 days of incubation at 20 ± 1°C according to manometric respirometry test was determined to be 0.85%.Based on the results, the test item, under the test conditions, was considered to be not biodegradable at 20 ± 1°C over a period of 28 days.

Biodegradation in water and sediment

Estimation Programs Interface (2018) prediction model was run to predict the half-life in water and sediment for the test chemical. 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 test chemical 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 test chemical 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 3% (i.e, reported as 2.71%), indicates that test chemical is not persistent in sediment.

 

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 (2018). If released into the environment, 79.9% 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 75 days (1800 hrs). Based on this half-life value of test chemical, 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

Using Bio-concentration Factor module Bio-concentration Factor of the test chemical was estimated to be 5973, 5972, 5970, 5942 and 5680 at pH range 1-10, 11, 12, 13 and 14, respectively. These value exceed the bio concentration threshold of 5000, indicating that the test chemical is expected to be very bioaccumulate in the aquatic organisms.

Adsorption / desorption

KOCWIN model of Estimation Programs Interface was used to predict the soil adsorption coefficient i.e Koc value of test chemical. The soil adsorption coefficient i.e Koc value of test chemical was estimated to be 2827 L/kg (log Koc=3.4513) by means of MCI method (at 25 deg C). This Koc value indicates that the test chemical has a strong sorption to soil and sediment and therefore have negligible to slow migration potential to ground water.

Additional information

Hydrolysis

In accordance with column 2 of Annex VIII of the REACH regulation, testing for this endpoint is technically not feasible and does not need to be conducted since the test chemical is insoluble in water.

Biodegradation in water

28-days Manometric respirometry test following the OECD guideline 301F to determine the ready biodegradability of the test chemical (Experimental study report, 2015). 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 100 mg/L, while that of inoculum was 10 ml/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 item and reference item. The % degradation of procedure control (Sodium Benzoate) was also calculated using BOD & ThOD and was determined to be 79.36%. The DO depletion(mg O2/l) in inoculum blank on 28th day was 24.2 mg O2/l which fulfilled the validity criteria (i.e., The DO depletion of the inoculums blank is normally 20-30 mg O2/l and should not be greater than 60 mg/l in 28 days) for inoculum blank (control). Degradation of Sodium acetate exceeds 64% after 4 days. Thus the activity of the inoculums is verified and the test is considered as valid.The BOD28 value of test chemical was observed to be 0.026 mgO2/mg. ThOD was calculated as 3.045 mgO2/mg. Accordingly, the % degradation of the test item after 28 days of incubation at 20 ± 1°C according to manometric respirometry test was determined to be 0.85%.Based on the results, the test item, under the test conditions, was considered to be not biodegradable at 20 ± 1°C over a period of 28 days.

Biodegradation in water and sediment

Estimation Programs Interface (2018) prediction model was run to predict the half-life in water and sediment for the test chemical. 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 test chemical 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 test chemical 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 3% (i.e, reported as 2.71%), indicates that test chemical is not persistent in sediment.

 

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 (2018). If released into the environment, 79.9% 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 75 days (1800 hrs). Based on this half-life value of test chemical, 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 chemical can be considered to be not biodegradable in water.

Bioaccumulation: aquatic / sediment

Various predicted data of the test chemical were reviewed for the bioaccumulation end point which are summarized as below:

 

In a prediction done by using Bio-concentration Factor module (ACD (Advanced Chemistry Development)/I-Lab predictive module, 2017)), Bio-concentration Factor of the test chemical was estimated to be 5973, 5972, 5970, 5942 and 5680 at pH range 1-10, 11, 12, 13 and 14, respectively. These value exceed the bio concentration threshold of 5000, indicating that the test chemical is expected to be very bioaccumulate in the aquatic organisms.

 

Another predicted data was estimated using SciFinder database (American Chemical Society (ACS), 2017) for predicting the bioconcentration factor (BCF) of test chemical. The bioconcentration factor (BCF) of test chemical was estimated to be 6420 at pH range 1-10 respectively (at 25 deg C) which exceeds the bio concentration threshold of 5000, indicating that the test chemical is expected to be very bioaccumulative in the food chain.

 

On the basis of above results for test chemical, it can be concluded that the BCF value of test substance was evaluated to be ranges from 5680 to 6420, which exceeds the bioconcentration threshold of 5000, indicating that the test chemical is expected to be very bioaccumulative in the food chain.

Adsorption / desorption

Various predicted data of the test chemical were reviewed for the adsorption end point which are summarized as below:

 

In aprediction done using theKOCWIN Programof Estimation Programs Interface was used to predict the soil adsorption coefficient i.e Koc value of test chemical. The soil adsorption coefficient i.e Koc value of test chemical was estimated to be 2827 L/kg (log Koc=3.4513) by means of MCI method (at 25 deg C). This Koc value indicates that the test chemical has a strong sorption to soil and sediment and therefore have negligible to slow migration potential to ground water.

 

The Soil Adsorption Coefficient i.e Koc value of test chemical was estimated using Adsorption Coefficient module program as Koc 17562, 17561, 17553, 17472 and 16701 at pH range 1-10, 11, 12, 13 and 14, respectively (logKoc - 4.2 ± 1.0)(ACD (Advanced Chemistry Development)/I-Lab predictive module, 2017)). The logKoc value indicates that the test chemical has a strong sorption to soil and sediment and therefore have negligible to slow migration potential to ground water.

 

Another soil adsorption coefficient i.e Koc value of test chemicalwas estimated using the SciFinder database (2017). The soil adsorption coefficient i.e Koc value of test chemical was estimated to be 18500 (logKoc = 4.267) at pH range 1-10, respectively (at 25 deg C). This Koc value indicates that the test chemical has a strong sorption to soil and sediment and therefore have negligible to slow migration potential to ground water.

 

From CompTox Chemistry Dashboard using OPERA (OPEn (quantitative) structure-activity Relationship Application)  V1.02 model in which calculation based on PaDEL descriptors (calculate molecular descriptors and fingerprints of chemical), the adsorption coefficient i.e KOC for test chemical was estimated to be 1840 L/kg (log Koc = 3.268).The predicted KOC result based on the 5 OECD principles. This Koc value indicates that the test chemical has a moderate sorption to soil and sediment and therefore have slow migration potential to ground water.

 

On the basis of above overall results for test chemical, it can be concluded that the log Koc value of test chemical was estimated to be ranges from3.268to4.267, respectively, indicating that the test chemicalhas a moderate to strong sorption to soil and sediment and therefore have negligible to slow migration potential to ground water.