Tributylmethylammonium chloride

Endpoint summary

Description of key information

Short term toxicity to fish:

In three 96-h acute toxicity studies, Fathead minnow were exposed to 75% methyltributylammonium chloride at the following nominal test material concentrations:

- Test 1-A (conducted with reconstituted fresh water): control (reconstituted fresh water), 2.4, 8.1, 27, 90 and 300 mg/L;

- Test 1-B (conducted with effluent and river water): control (effluent and river water), 2.4, 8.1, 27, 90 and 300 mg/L;

- Test 2 (conducted with effluent and river water): control (effluent and river water), 100, 200, 400, 800 and 1600 mg/L.

 For tests 1-A and B mortality was not above 50% even at the highest concentration tested. Therefore, the LC50 value can assumed to be higher than the highest nominal test material concentration (300 mg/L, corresponding with 225 mg MTBAC/L). In test 2, conducted with 6.8% effluent solution in Ohio River water, the 96h-LC50 was 987.9 mg/L.

The present toxicity study is classified as reliable with restrictions since the water quality of Ohio river water was not properly determined (e.g. dissolved organic carbon), analytical confirmation of test concentrations was not performed and the fish biomass loading was not reported for any of the tests conducted.

For the evaluation of the intrinsic toxicity of the substance, only the test results with reconstituted water should be used, because in the other tests (applying 6.8% effluent solution in Ohio River water), the test medium is not well defined.

 

Long term toxicity to fish:

Based on the prediction done using ECOSAR version 1.1, the long term toxicity on fish was predicted for test chemical. On the basis of effects observed in a static freshwater system, the NOEC value for the test chemical is estimated to be 397.33 mg/l for fish for 28 days of exposure duration. It can be concluded that the test chemical can be considered as non-toxic to fish at environmentally relevant concentrations and can be considered not-classified as per the CLP classification criteria. 

 

Short term toxicity to aquatic invertebrate:

In two 48-h acute toxicity study, water fleas ceriodaphnia dubia were exposed to methyltributylammonium chloride at nominal test material concentrations of 0 (control), 8.1, 27, 90, 300 and 1000 mg/L.In the test conducted with reconstituted fresh water the 48h-EC50 was 12.3 mg test material/L.This corresponds with a nominal 48h-EC50 of 9.2 mg MTBAC/L. Test 2, conducted with 6.8% industrial effluent solution in Ohio River water, showed that water fleas were less sensitive to methyltributylammonium chloride toxicity compared to the test conducted with reconstituted fresh water. The resulting 48h-EC50 was 52.4 mg test material/L. This corresponds with a nominal 48h-EC50 of 39 mg MTBAC/L.

Analytical confirmation of test concentrations were not performed and the water quality of Ohio river water was not properly determined (e.g.dissolved organic carbon). Nevertheless, since test solutions were renewed after 24h and the read-across substance TMAH was stable in an algae study (Scheerbaum, 2011), it can be assumed that the actual exposure to MTBAC was in agreement with the nominal MTBAC concentration.

For the evaluation of the intrinsic toxicity of the substance, only the test results with reconstituted water should be used, because in the other tests (applying 6.8% industrial effluent solution in Ohio River water), the test medium was not well defined.

 

 Long term toxicity to aquatic invertebrate:

Long term toxicity test to aquatic invertebrate was performed using OECD 211 study guidelines (Daphnia Magna Reproduction test). Test organisms used in the study was daphnia magna neonates of strain STRAUS. The study was conducted for the period of 21 days and number of living offsprings produced per living parent daphnia is calculated every day. The test chemical was dissolved in the M7 medium, stability study was conducted in M7 medium by dissolving 10 mg of test solution in 100 ml of medium which was kept under test conditions for 96 hours and sample at regular intervals of 24 hours was taken and checked for analytical stability. At 0.01 mg/l and 10 mg/L test chemical was with in the range of 100 ± 20% of initial test concentrations which was measured by using LCMS. Based on the stability results chemical semi static conditions was used in the study with a minimum renewal of three times a week. Gravid Parent Daphnids of age greater than 3 weeks was acclimitised for 2 days under test conditions. Offsprings obtained in the from second brood whose age < 24 hours was separated and exposed at different test concentrations for the main study. Based on the available data on short term toxicity test main study was conducted by taking concentrations of 0.0625, 0.125, 0.25, 0.5, and 1 mg/L, 0.5, and 1 mg/L along with one control group with M7 medium. 100 ml glass beakers were used with fill volume of 50 ml test solutions of different concentrations. Each test vessel was loaded with one offspring, for each test concentrations 10 replicates was used and each replicate has one daphnia, same was followed in control as well. Al beakers were checked for the pH and DO at every renewal day and recorded. The temperature, DO and pH in the control, 19 ± 0.5°C, day 0- 7.9 and day 21- 8.1, and Day 0 -7.5 and at Day 21 - 7.9 respectively. All parent daphnids were feed with freshwater algae (P. Subcapitata) during the time of renewal with quantity of 0.1-0.2 mg/carbon/daphnia. The photoperiod of 16 hours light and 8 hours dark conditions was maintained with light intensity 1221.75 lux. The number of living off springs produced per parent at each concentration was recorded, which is presented in the tables sections. The first offsprings observed on the control was on day 10. The average number of offspings produced per living parent was 81.8, 77.5, 75.75, 75.75, 52.6 and 37 in control, 0.0625, 0.125, 0.25, 0.5, and 1 mg/L respectively. Following the neonate production mortality of parent was also recorded, At concentration of 0.0625, 0.125, and control there was no mortality was observed in exposed populations, whereas, at concentrations of 0.25, 0.5, and 1 mg/L a percent of 20, 50 and 90 was observed. All exposure concentrations of pre and post renewal were analytical measured, using LCMS. Test chemical concentrations in old samples with concentrations 0.0625, 0.125, 0.25, 0.5, and 1 mg/L were in the range of 100.8 – 112, 80.8 -89.6, 81.2 – 94, 80.8 - 90.6, and 96.7 - 98.0%respectively. Test chemical concentrations in new samples with concentrations 0.0625, 0.125, 0.25, 0.5, and 1 mg/L were in the range of  105.6 – 112%, 89.6 - 99.2%, 86 - 98.8, 87.2 - 97.8 and 90.3 - 99.3 respectively. Which was found to be in the range of 100± 20% of initial test concentrations. All the validity crieria including the CV of offsprring production were with in the acceptibility range as per study guideline. Based on the outcomes, the NOEC was reported to be 0.25 mg/L considering the reproductive effects and LC50 is 0.46 mg/L considering the parent mortality. Thus chemical can be classified as category aquatic chronic category 2 as per CLP classification criteria.

 

Toxicity to aquatic algae and cyanobacteria:

A toxicity test with Pseudokirchnerella subcapitata was carried out with TMAH according to OECD 201 and GLP under static conditions. Analytical monitoring was conducted. The TMAH concentrations in test solutions were maintained within ± 20% of nominal concentrations throughout the test. Thus the value was estimated with nominal concentrations. The nominal 72h-ErC50 value and NOECr value were 96.3 and 6.25 mg/L, respectively.

 

Toxicity to microorganism:

MTBAC was concluded to be not toxic to the inoculum in a ready biodegradability test carried out according to OECD301B and GLP (Soeter, 2015) at a concentration of 18 mg/L, as in the toxicity control more than 25% biodegradation occurred within 14 days (40%, based on ThCO2).

In accordance with IR/CSA guidance R.10 (May 2008), paragraph 10.4.2, this concentration can be used as a NOEC value for the calculation of a PNEC for STP microorganisms. The conclusion on the toxicity of MTBAC to STP micro-organisms is supported by a study with the structurally similar substance TMAH pentahydrate (see read-across justification in IUCLID section 13).

Additional information

Short term toxicity to fish:

In three 96-h acute toxicity studies, Fathead minnow were exposed to 75% methyltributylammonium chloride at the following nominal test material concentrations:

- Test 1-A (conducted with reconstituted fresh water): control (reconstituted fresh water), 2.4, 8.1, 27, 90 and 300 mg/L;

- Test 1-B (conducted with industrial effluent in river water): control (effluent in river water), 2.4, 8.1, 27, 90 and 300 mg/L;

- Test 2 (conducted with industrial effluent in river water): control (effluent in river water), 100, 200, 400, 800 and 1600 mg/L.

 For tests 1-A and B mortality was not above 50% even at the highest concentration tested. Therefore, the LC50 value can assumed to be higher than the highest test concentration (>300 mg test material/L). In test 2, conducted with 6.8% industrial effluent solution in Ohio River water, the 96h-LC50 was 987.9 mg test material/L.

The present toxicity study is classified as reliable with restrictions since the water quality of Ohio river water was not properly determined (e.g.dissolved organic carbon), the fish biomass loading was not reported and analytical confirmation of test concentrations was not performed for any of the tests conducted. Since test solutions were partly (50% of the volume) renewed after 48h and the read-across substance TMAH was stable in an algae study (TMAH Consortium 2005 and Scheerbaum 2001), it can be assumed that the actual exposure to MTBAC was in agreement with the nominal MTBAC concentration.

For the evaluation of the intrinsic toxicity of the substance, only the test results with reconstituted water should be used, because in the other tests (applying 6.8% industrial effluent solution in Ohio River water), the test medium was not well defined.

 

Long term toxicity to fish:

Based on the prediction done using ECOSAR version 1.1, the long term toxicity on fish was predicted for test chemical. On the basis of effects observed in a static freshwater system, the NOEC value for the test chemical is estimated to be 397.33 mg/l for fish for 28 days of exposure duration. It can be concluded that the test chemical can be considered as non-toxic to fish at environmentally relevant concentrations and can be considered not-classified as per the CLP classification criteria. 

 

Short term toxicity to aquatic invertebrate:

In two 48-h acute toxicity study, water fleas ceriodaphnia dubia were exposed to methyltributylammonium chloride at nominal test material concentrations of 0 (control), 8.1, 27, 90, 300 and 1000 mg/L.In the test conducted with reconstituted fresh water the 48h-EC50 was 12.3 mg test material/L.This corresponds with a nominal 48h-EC50 of 9.2 mg MTBAC/L. Test 2, conducted with 6.8% industrial effluent solution in Ohio River water, showed that water fleas were less sensitive to methyltributylammonium chloride toxicity compared to the test conducted with reconstituded fresh water. The resulting 48h-EC50 was 52.4 mg test material/L. This corresponds with a nominal 48h-EC50 of 39 mg MTBAC/L.

Analytical confirmation of test concentrations were not performed and the water quality of Ohio river water was not properly determined (e.g.dissolved organic carbon). Nevertheless, since test solutions were renewed after 24h and the read-across substance TMAH was stable in an algae study (Scheerbaum, 2011), it can be assumed that the actual exposure to MTBAC was in agreement with the nominal MTBAC concentration.

For the evaluation of the intrinsic toxicity of the substance, only the test results with reconstituted water should be used, because in the other tests (applying 6.8% industrial effluent solution in Ohio River water), the test medium was not well defined.

 

 

Long term toxicity to aquatic invertebrate:

Data available for the chemicals has been reviewed to determine the long term toxicity of test chemical to aquatic invertebrates. The results of studies are as summarized below:

Long term toxicity test to aquatic invertebrate was performed using OECD 211 study guidelines (Daphnia Magna Reproduction test). Test organisms used in the study was daphnia magna neonates of strain STRAUS. The study was conducted for the period of 21 days and number of living offsprings produced per living parent daphnia is calculated every day. The test chemical was dissolved in the M7 medium, stability study was conducted in M7 medium by dissolving 10 mg of test solution in 100 ml of medium which was kept under test conditions for 96 hours and sample at regular intervals of 24 hours was taken and checked for analytical stability. At 0.01 mg/l and 10 mg/L test chemical was with in the range of 100 ± 20% of initial test concentrations which was measured by using LCMS. Based on the stability results chemical semi static conditions was used in the study with a minimum renewal of three times a week. Gravid Parent Daphnids of age greater than 3 weeks was acclimitised for 2 days under test conditions. Offsprings obtained in the from second brood whose age < 24 hours was separated and exposed at different test concentrations for the main study. Based on the available data on short term toxicity test main study was conducted by taking concentrations of 0.0625, 0.125, 0.25, 0.5, and 1 mg/L, 0.5, and 1 mg/L along with one control group with M7 medium. 100 ml glass beakers were used with fill volume of 50 ml test solutions of different concentrations. Each test vessel was loaded with one offspring, for each test concentrations 10 replicates was used and each replicate has one daphnia, same was followed in control as well. Al beakers were checked for the pH and DO at every renewal day and recorded. The temperature, DO and pH in the control, 19 ± 0.5°C, day 0- 7.9 and day 21- 8.1, and Day 0 -7.5 and at Day 21 - 7.9 respectively. All parent daphnids were feed with freshwater algae (P. Subcapitata) during the time of renewal with quantity of 0.1-0.2 mg/carbon/daphnia. The photoperiod of 16 hours light and 8 hours dark conditions was maintained with light intensity 1221.75 lux. The number of living off springs produced per parent at each concentration was recorded, which is presented in the tables sections. The first offsprings observed on the control was on day 10. The average number of offspings produced per living parent was 81.8, 77.5, 75.75, 75.75, 52.6 and 37 in control, 0.0625, 0.125, 0.25, 0.5, and 1 mg/L respectively. Following the neonate production mortality of parent was also recorded, At concentration of 0.0625, 0.125, and control there was no mortality was observed in exposed populations, whereas, at concentrations of 0.25, 0.5, and 1 mg/L a percent of 20, 50 and 90 was observed. All exposure concentrations of pre and post renewal were analytical measured, using LCMS. Test chemical concentrations in old samples with concentrations 0.0625, 0.125, 0.25, 0.5, and 1 mg/L were in the range of 100.8 – 112, 80.8 -89.6, 81.2 – 94, 80.8 - 90.6, and 96.7 - 98.0%respectively. Test chemical concentrations in new samples with concentrations 0.0625, 0.125, 0.25, 0.5, and 1 mg/L were in the range of  105.6 – 112%, 89.6 - 99.2%, 86 - 98.8, 87.2 - 97.8 and 90.3 - 99.3 respectively. Which was found to be in the range of 100± 20% of initial test concentrations. All the validity crieria including the CV of offsprring production were with in the acceptibility range as per study guideline. Based on the outcomes, the NOEC was reported to be 0.25 mg/L considering the reproductive effects and LC50 is 0.46 mg/L considering the parent mortality. Thus chemical can be classified as category aquatic chronic category 2 as per CLP classification criteria.

In first study an experiment was performed to determine the Long term toxicity effect on reproduction of Daphnia magna for 20 days as per OECD Guideline 211 (Daphnia magna Reproduction Test). In this experiment Daphnia magna less then 24h old were used at the initiation of the test. They were exposed to various concentrations of test chemicals .The test medium used was water which is obtained from 33% evian water and 67% volvic water which are commonly marked as mineral water in Japan and it was changed every 1 or 2 days, neonatal were counted every day. The total number of fleas born over 21 days in the test fluid of each concentration and the total number born in the control group were statistically processed to determine NOEC and LOEC values.

After 21 days, of exposure of test chemical to Daphnia magna the NOEC was observed to be 0.125 mg/l and LOEC value was determined to be 0.25 mg/L .On the basis of above effect concentration it can be considered that test material has chronic effects on aquatic invertebrate and can be classified as aquatic chronic 2 as per CLP criteria.

 

Another study was conducted to access the effect of test chemical on reproduction of aquatic invertebrates Daphnia magna after the exposure of test chemical for 21 days. This study was conducted in accordance with the OECD Guideline 211 (Daphnia magna Reproduction Test). After 21 days of exposure of test chemical to daphnia magna the NOEC value was determined to be 0.98 mg/L and EC50 value was determined to be in range of 0.98- 2.7 mg/L, On the basis of these values test chemical is considered to be toxic and classified as aquatic chronic 2 as per the CLP classification criteria.

 

By considering results of both the studies mentioned above and applying weight of evidence approach the NOEC value of test chemical was determined to be in range from 0.125 mg/L to 0.98 mg/l after exposure of test chemical for 21 days. The range NOEC value indicates that the substance is likely to be toxic to aquatic algae and can be classified as aquatic chronic 2 per the CLP classification criteria.

 

Toxicity to aquatic algae and cyanobacteria:

There are two studies available on the structural related substance Tetramethylammonium hydroxide (TMAH) and there is one study available with the structural related substance Tetrabutylammonium bromide (TBAB), which can be used in a weight-of-evidence approach (see read-across document attached in IUCLID section 13).

The toxicity of the structural analogue Tetramethylammonium hydroxide to P.subcapita  was examined according to OECD 201 and GLP under static conditions (TMAH Consortium, 2005). Analytical monitoring was conducted. The TMAH concentrations in test solutions were maintained within ± 20% of nominal concentrations throughout the test and the effect concentrations were based on nominal concentrations. The 72h-ErC50 value and NOEC value were 96.3 and 6.25 mg/L, respectively.

The toxicity of TMAH to D.Subcapita was examined in accordance with OECD 201, EU Method C.3 (Algal Inhibition test) and GLP under static conditions (Scheerbaum, 2001). The nominal 72h-ErC50 value and NOEC value to D.Subcapita were >251 and 31.4 mg/L, respectively. The recovery rates of samples taken at the start and the end of the test based on DOC measurements were > 80% and therefore it is deemed acceptable to express the results as nominal values. As the pH was significantly increased at the high test concentration, a neuralised (pH control) 251 mg TMAH/L was also tested showing no significant effects; it can thus be concluded that the effects were pH dependent.

 

The toxicity of Tetrabutylammonium bromide (TBAB) to P.subcapita was determined in accordance with OECD 201 and EPA OPPTS 850.4500 (Tier I and II) guidelines (non-GLP) (Cho et al., 2008). Nominal concentrations were not confirmed by analytical measurements. However, since the read-across substance TMAH was stable in the above mentioned algae studies, it can be assumed that the actual concentrations were in agreement with the nominal concentrations. The nominal 72h-ErC50 v

alue of Tetrabutylammonium bromide was 722 mg/L.

Based on the results of tests with the structural analogues TMAH and TBAB, it is reasonably predicted that the ErC50 of MTBAC to algae is higher than 100 mg/L. Based on the results with the structural analogue TMAH, it is reasonably predicted that the NOEC of MTBAC to algae is higher than 1 mg/L.

 

Toxicity to microorganism:

The conclusion on the toxicity of MTBAC to STP micro-organisms is supported by a study with the structurally similar substance TMAH pentahydrate (see read-across justification in IUCLID section 13). The toxicity of TMAH pentahydrate to microorganisms was determined in a 3 h activated sludge respiration inhibition study carried out according to OECD guideline No. 209 and GLP principles (Desmares-Koopmans, 2013). The study was considered valid and reliable.

In a combined limit/range-finding test, microorganisms in activated sludge were exposed to TMAH pentahydrate at concentrations of 10, 100 and 1000 mg/L under static conditions. The substance significantly inhibited the respiration rate of waste water (activated sludge) at 1000 mg/L. However, the EC50 exceeded the highest test concentration of 1000 mg/L and no NOEC could be determined. Based on the molecular weight of TMAH pentahydrate (181.2 g/mol) and TMAH (91.15 g/mol) it was calculated that the EC50 value of > 1000 mg/L test material (TMAOH pentahydrate) corresponds with > 503 mg/L TMAH.