1-dodecylpyridinium chloride

Endpoint summary

Description of key information

Hydrolysis

On the basis of the experimental studies of the test chemical and applying the weight of evidence approach, the hydrolysis half-life value of the test chemical can be expected to be ranges from 150 days to ≥ 1 yr, at pH range 4-9 and at a temperature of 20°C, respectively. Thus, based on this half-life value, it can be concluded that the test chemical can be considered to be not hydrolysable in water.

Biodegradation in water

35-days Closed Bottle test following the OECD guideline 301 D to determine the ready biodegradability of the test chemical (Experimental study report, 2018). The study was performed at a temperature of 20°C. The test system included control, test item and reference item. Polyseed were used as a test inoculum for the study.The concentration of test and reference item (Sodium Benzoate) chosen for both the study was 4 mg/L, while that of inoculum was 32 ml/l. OECD mineral medium was used for the study. 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 (reference item) was also calculated using BOD & ThOD and was determined to be 75.3%. Degradation of Sodium Benzoate exceeds 45.18% on 7 days & 70.48% on 14th day. The activity of the inoculum was thus verified and the test can be considered as valid.The BOD35 value of test chemical was observed to be 1.1 mgO2/mg. ThOD was calculated as 2.64 mgO2/mg. Accordingly, the % degradation of the test item after 35 days of incubation at 20 ± 1°C according to Closed Bottle test was determined to be 41.66%. Based on the results, the test item, under the test conditions, was considered to be ultimate inherently biodegradable in nature.

Biodegradation in water and sediment

Estimation Programs Interface (2017) prediction model was run to predict the half-life in water and sediment for the test chemical. If released in to the environment, 9.39% 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 15 days (360 hrs). The half-life (15 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 135 days (3240 hrs). Based on this half-life value, it indicates that test chemical is 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 (2017). If released into the environment, 59.8% 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 30 days (720 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

In accordance with column 2 of Annex IX of the REACH regulation, testing for this endpoint is scientifically not necessary and does not need to be conducted since the test chemical has a low potential for bioaccumulation based on logKow ≤ 3.

Adsorption / desorption

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 (Experimental study report, 2018). A test item solution was prepared by accurately weighing 4 mg of test item and diluted with ACN up to10 ml. Thus, the test solution concentration was 400 mg/l. The pH of test substance was 5.3. 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(Annex - 2).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 were chosen according to functional similarity with the test substance and calibration graph prepared. The reference substances were Xylene, Ethylbenzene, Toluene, Naphthalene, phenanthrene having Koc value ranging from 2.369 to 4.09. The Log Koc value of test chemical was determined to be 3.150 ± 0.002 at 25°C.This logKoc value indicates that the test chemical has a moderate sorption to soil and sediment and therefore have slow migration potential to ground water.

Additional information

Hydrolysis

Data available for the test chemical has been reviewed to determine the half-life of hydrolysis as a function of pH. The studies are as mentioned below:

The half-life value of test chemical was determined at a pH range 5-9, respectively. The estimated half-life value of test chemical was determined to be ranges from 150 to 183 days and 379 days at a pH range of 5-9, respectively. Thus, test chemical was reported to be hydrolytically stable under abiotic and buffered conditions. Based on the half-life values, it is concluded that the chemical is not hydrolysable.

In an another study, the half-life of the test chemical was determined at different pH range. The study was performed at pH of 4, 7 and 9, & at a temperature of 20°C, respectively. The half-life period of test chemical was determined to be ≥ 1 yr at pH 4, 7 and 9, respectively & at a temperature of 20°C and thus test chemical was reported to be hydrolytically stable. On the basis of this, test chemical is considered to be not hydrolysable.

On the basis of the experimental studies of the test chemical and applying the weight of evidence approach, the hydrolysis half-life value of the test chemical can be expected to be ranges from 150 days to  ≥  1 yr, at pH range 4-9 and at a temperature of 20°C, respectively. Thus, based on this half-life value, it can be concluded that the test chemical can be considered to be not hydrolysable in water.

Biodegradation in water

Various experimental studies of the test chemical were reviewed for the biodegradation end point which are summarized as below:

 

In an experimental key study from study report (2018),35-days Closed Bottle test following the OECD guideline 301 D to determine the ready biodegradability of the test chemical. The study was performed at a temperature of 20°C. The test system included control, test item and reference item. Polyseed were used as a test inoculum for the study. The concentration of test and reference item (Sodium Benzoate) chosen for both the study was 4 mg/L, while that of inoculum was 32 ml/l. OECD mineral medium was used for the study. 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 (reference item) was also calculated using BOD & ThOD and was determined to be 75.3%. Degradation of Sodium Benzoate exceeds 45.18% on 7 days & 70.48% on 14th day. The activity of the inoculum was thus verified and the test can be considered as valid. The BOD35 value of test chemical was observed to be 1.1 mgO2/mg. ThOD was calculated as 2.64 mgO2/mg. Accordingly, the % degradation of the test item after 35 days of incubation at 20 ± 1°C according to Closed Bottle test was determined to be 41.66%. Based on the results, the test item, under the test conditions, was considered to be ultimate inherently biodegradable in nature.

 

Another Biodegradation study from peer reviewed journal (ROBERT S. BOETHLING, et. al., 1984) was conducted for 30 days for evaluating the percentage biodegradability of test chemical. The study was performed according to die-way test. Sewage and river water were used as a test inoculums for the study. Initial test substance conc. used in the study was 30 mg/l. The percentage degradation of test chemical was determined to be 0% after a period of 30 days. Thus, based on percentage degradation, test chemical is considered to be not readily biodegradable in nature.

 

For the test chemical, additional biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of test chemical (B. BALEUX et. al., 1977). The study was performed using residual bottle method under aerobic conditions. Waste water was used as a test inoculums for the study. Initial test substance conc. used in the study was 20 mg/l. The percentage degradation of test chemical was determined to be 0% by using spectrophotometer parameter after a period of 28 days. Thus, based on percentage degradation, test chemical is considered to be not readily biodegradable in nature.

 

Although other studies from peer reviewed journal indicates that the test chemical is not readily biodegradable, but on the basis of detailed experimental study result from study report (K1) and as per the OECD guideline, it has been concluded that the test chemical is considered to be ultimate inherently biodegradable in nature.

Biodegradation in water and sediment

Estimation Programs Interface (2017) prediction model was run to predict the half-life in water and sediment for the test chemical. If released in to the environment, 9.39% 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 15 days (360 hrs). The half-life (15 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 135 days (3240 hrs). Based on this half-life value, it indicates that test chemical is 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 (2017). If released into the environment, 59.8% 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 30 days (720 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 ultimate inherently biodegradablein nature.

Bioaccumulation: aquatic / sediment

In accordance with column 2 of Annex IX of the REACH regulation, testing for this endpoint is scientifically not necessary and does not need to be conducted since the test chemical has a low potential for bioaccumulation based on logKow ≤ 3.

Adsorption / desorption

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

 

In an experimental key study from study report (2018),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 (Experimental study report, 2018). A test item solution was prepared by accurately weighing 4 mg of test item and diluted with ACN up to10 ml. Thus, the test solution concentration was 400 mg/l. The pH of test substance was 5.3. 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(Annex - 2).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 were chosen according to functional similarity with the test substance and calibration graph prepared. The reference substances were Xylene, Ethylbenzene, Toluene, Naphthalene, phenanthrene having Koc value ranging from 2.369 to 4.09. The Log Koc value of test chemical was determined to be 3.150 ± 0.002 at 25°C.This logKoc value indicates that the test chemical has a moderate sorption to soil and sediment and therefore have slow migration potential to ground water.

 

For the test chemical, Soil adsorption coefficient (Koc) study was conducted for evaluating the adsorption capacity of test chemical onto different adsorbents (handbook, 1999). The adsorption of test chemical onto different adsorbents was examined at equilibrium conc. from 10 to 300 µM/l. Although Koc value of test chemical was not known, but it was reported that the adsorption maximum of test chemical for soils and compost was less than 10 µmol/g. There is no significant correlation between adsorption behaviour and organic matter contents in soils and composts. Thus, based on this, it indicates that the test chemical has a low sorption to soil and sediment and therefore have moderate migration potential to ground water.

 

On the basis of above overall results for test chemical, it can be concluded that the test chemical has a low to moderate sorption to soil and sediment and therefore have moderate to slow migration potential to ground water.