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Biodegradation in water

Biodegradability of Tetrabutylammonium hydrogen sulphate (CAS no. 32503 -27 -8) is predicted using QSAR toolbox version 3.4with logKow as the primary descriptor (2017). Test substance undergoes 41.2% degradation by CO2 evolution parameter in 28 days Thus, based on percentage degradation, the test chemical Tetrabutylammonium hydrogen sulphate was estimated 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 Tetrabutyl ammonium hydrogen sulphate (CAS No.32503 -27 -8). If released in to the environment, 17.8% 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 8.666 days (208 hrs). The half-life (8.666 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 Tetrabutylammonium hydrogen sulphate in sediment is estimated to be 77.916 days (1870 hrs). Based on this half-life value (77.916 days), it indicates that the chemical Tetrabutylammonium hydrogen sulphate is not persistent in sediment.

Biodegradation in soil

The half-life period of Tetrabutylammonium hydrogen sulphate (CAS No. 32503 -27 -8) 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, 80% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of Tetrabutylammonium hydrogen sulphate in soil is estimated to be 17.333 days (416 hrs). Based on this half-life value of Tetrabutylammonium hydrogen sulphate, 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:

The estimated bio concentration factor (BCF) for tetrabutylammonium hydrogen sulphate is 70.79 L/kg whole body w.w which does not exceed the bio concentration threshold of 2000. Thus it is concluded that tetrabutylammonium hydrogen sulphate is not expected to bioaccumulate in the food chain.

Adsorption / desorption:

The adsorption coefficient Koc in soil and in sewage sludge Tetrabutylammonium hydrogen sulphate(CAS No.32503-27-8) 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 1.45 to 4.09. The Log Koc value was found to be 3.0468 ± 0.00057at 25°C.

Henry's Law constant:

Henry's Law constant of test substance tetrabutylammonium hydrogen sulphate was estimated to be 0.00000000000399 (3.99E-012)Pa-m3/mole at 25 deg.C

Additional information

Biodegradation in water

Various predicted data for the test compound Tetrabutylammonium hydrogen sulphate(CAS No. 32503-27-8) and the experimental reports for its read across substance were reviewed for the biodegradation end point, which are summarized as below:

 

In a predicted data done SSS (2017) by usingQSAR toolbox version 3.4 with logKow as the primary descriptor, percentage biodegradability oftest chemical Tetrabutylammonium hydrogen sulphate (CAS no. 32503 -27 -8) was estimated. Test substance undergoes 41.2% degradation by CO2 evolution parameter in 28 days Thus, based on percentage degradation, the test chemical Tetrabutylammonium hydrogen sulphate was estimated to be not readily biodegradable in nature.

In another prediction using the Estimation Programs Interface Suite (EPI suite, 2017), the biodegradation potential of the test compound Tetrabutylammonium hydrogen sulphate (CAS no. 32503 -27 -8) 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 Tetrabutyl ammonium hydrogen sulphate is expected to be not readily biodegradable.

 

Another weight of evidence study of biodegradation was conducted for 28 days for evaluating the percentage biodegradability of read across substance Tetrapropylammonium bromide (CAS no. 1941 -30 -6) (J-CHECK, 2016). Concentration of inoculum i.e, sludge used was 30 mg/l and initial substance conc. used in the study was 100 mg/l. The percentage degradation of read across substance was determined to be 0% by O2 consumption, BOD, TOC removal, test mat. analysis and IC parameter in 28 days. Thus, based on percentage degradation, Tetrapropyl ammonium bromide was considered to be not readily biodegradable in nature.

 

In an additional study of read across substance Didecyl dimethyl ammonium chloride (CAS no. 7173-51-5) from authoritative database (J-CHECK, 2016), biodegradation experiment was carried out for 28 days for evaluating the percentage biodegradability of read across substance Didecyl dimethyl ammonium chloride. The study was performed according to OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I)) and other guideline "Biodegradation test of a chemical substance using a microorganism etc." provided in "the Notice on the Test Method Concerning New Chemical Substances", respectively. Concentration of inoculum i.e, sludge used was 30 mg/l and initial substance conc. used in the study was 100 mg/l. The percentage degradation of read across substance was determined to be 0% by BOD, O2 consumption, test mat. analysis and LC-MS parameter in 28 days. Thus, based on percentage degradation, Didecyl dimethyl ammonium chloride was considered to be not readily biodegradable in nature.

 

On the basis of above results for target and read across substance, it can be concluded that the test substanceTetrabutylammonium hydrogen sulphate 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 Tetrabutyl ammonium hydrogen sulphate (CAS No.32503 -27 -8). If released in to the environment, 17.8% 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 8.666 days (208 hrs). The half-life (8.666 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 Tetrabutylammonium hydrogen sulphate in sediment is estimated to be 77.916 days (1870 hrs). Based on this half-life value (77.916 days), it indicates that the chemical Tetrabutylammonium hydrogen sulphate is not persistent in sediment.

Biodegradation in soil

The half-life period of Tetrabutylammonium hydrogen sulphate (CAS No. 32503 -27 -8) 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, 80% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of Tetrabutylammonium hydrogen sulphate in soil is estimated to be 17.333 days (416 hrs). Based on this half-life value of Tetrabutylammonium hydrogen sulphate, 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 substanceTetrabutylammonium hydrogen sulphate can be considered to be not readily biodegradable in nature.

Bioaccumulation: aquatic / sediment:

For bioaccumulation in aquatic environment, 3 studies for the test chemical Tetrabutylammonium hydrogen sulphate (Cas no. 32503-27-8) were reviewed as follows:

From the EPI suite Program (2017); using BCFBAF (v3.01) model the Bioaccumulation factor (BCF) was predicted to be 70.79 L/kg wet-wt at 25 deg.C for target tetrabutylammonium hydrogen sulphate which does not exceed the bio concentration threshold of 2000. Thus it is concluded that tetrabutylammonium hydrogen sulphate is not expected to bioaccumulate in the food chain.

Another prediction database PBT profiler; 2017 indicated the Bioaccumulation factor (BCF) was predicted to be 71 L/kg wet-wt at 25 deg.C for target chemical tetrabutylammonium hydrogen sulphate.

 

In addition, a study from Japan chemicals collborative knowledge database (J-check); 2017 for the read across chemical Tetra-n-propylammonium bromide (Cas no. 1941-30-6) indicate that according to guideline OECD Guideline 305 C (Bioaccumulation: Test for the Degree of Bioconcentration in Fish), the BCF value for Tetra-n-propylammonium bromide (Cas no. 1941-30-6) was determined to be <= 0.3 L/kg at dose concentration 2 mg/L and <= 2.8 L/kg at dose concentration 0.2 mg/L on test organism Cyprinus carpio during 6 weeks period. Thus based on the BCF value it is concluded that the test substance Tetra-n-propylammonium bromide is non bioaccumulative in nature.

 

Experimental study data of read across chemical supports the predicted result of the target chemical which indicate the Bioaccumulation value (BCF) is in the range <= 0.3 -71 for target chemical Tetrabutylammonium hydrogen sulphate.Thus based on available BCF range, we can conclude that the test substance Tetrabutylammonium hydrogen sulphate (Cas no. 32503-27-8) is non bioaccumulative in aquatic environment.

Adsorption / desorption:

For adsorption in soil endpoint 2 studies for the test chemical Tetrabutylammonium hydrogen sulphate (Cas no. 32503-27-8) were reviewed as follows:

First study from experimental report by UERL study result;2017 indicate that the adsorption coefficient Koc in soil and in sewage sludge Tetrabutylammonium hydrogen sulphate(CAS No.32503-27-8) 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 1.45 to 4.09. The Log Koc value was found to be 3.0468 ± 0.00057at 25°C.

Additional data from prediction model also support the experimental result i.e the Soil Adsorption Coefficient (Koc value) of  Tetrabutylammonium hydrogen sulphate was estimated using EPI suite KOCWIN model (v2.00) as Koc 6325 L/kg (log Koc=3.801) by means of MCI method at 25 deg.C. This Koc value indicates that the substance Tetrabutylammonium hydrogen sulphate has a strong sorption to soil and sediment and therefore has negligible to slow migration potential to groundwater.

Thus both studies give the conclusion that chemical Tetrabutylammonium hydrogen sulphate (Cas no. 32503-27-8) is slow to immobile in soil/sediment.

Henry's Law constant:

Henry's Law constant of test substance tetrabutylammonium hydrogen sulphate was estimated to be 0.00000000000399 (3.99E-012)Pa-m3/mole at 25 deg.C