Tributylethylammonium ethyl sulphate

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

14 March 2017 - 13 April 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

Version / remarks:

17 July 1992

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

- Soluble in water: yes
- Stability in water: stable

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of activated sludge: 'Waterschap Aa en Maas', 's-Hertogenbosch, The Netherlands, receiving predominantly domestic sewage.
- Storage conditions: under continuous aeration until further treatment
- Pretreatment: before use, the sludge was allowed to settle (31 minutes) and the supernatant liquid was used as inoculum at the amount of 10 mL/L of mineral medium.
- Concentration of sludge: 4.4 g suspended solids/L

Duration of test (contact time):

28 d

Initial conc.:

21 mg/L

Based on:

test mat.

Initial conc.:

12 mg/L

Based on:

TOC

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: according to OECD 301B
- Test temperature: 22-24°C
- pH: 7.6 (start), 7.7 (day 14), 7.6 (day 28)
- pH adjusted: no
- Aeration of dilution water: yes
- Suspended solids concentration: not indicated: 10 mL supernatant of a settled solution containing 4.4 g suspended solids/L suspension was taken to use as inoculum.
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: 2 litre brown coloured glass bottles
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: by synthetic air (CO2 < 1 ppm; at a rate of approx. 1-2 bubbles per second/ ca. 30-100 mL/min)
- Details of trap for CO2: three bottles filled with 100 mL 0.0125 M Ba(OH)2) were connected in series to the exit air line of each test bottle.
- Test performed in open system: no
- Other: phenolphthalein (1% solution in ethanol, Merck) was used as pH-indicator.

SAMPLING
- Sampling frequency: titrations were made on day 2, 5, 7, 9, 15, 19, 23, 27, and 29. Titrations for the positive and toxicity control were made over a period of at least 14 days. Each time the CO2-absorber nearest to the test bottle was removed for titration; each of the remaining two absorbers was moved one position in the direction of the test bottle. A new CO2-absorber was placed at the far end of the series.
- Sampling method: the amount of CO2 produced was determined by titrating Ba(OH)2 with 0.05 M standardized HCl

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes, 2 bottles
- Abiotic sterile control: no
- Toxicity control: yes, 1 bottle
- Other: positive control containing reference item and inoculum (1 bottle)

STATISTICAL METHODS: no statistical analysis was used

Reference substance:

acetic acid, sodium salt

Remarks:

Purity: 99.6%

Key result

Parameter:

% degradation (CO2 evolution)

Remarks:

mean of duplicate bottles

Value:

4

Sampling time:

28 d

Details on results:

- The ThCO2 of the test substance was calculated to be 2.07 mg CO2/mg. The ThCO2 of the reference item was calculated to be 1.07 CO2/mg.
- The test substance biodegraded for 0% and for 8% in duplicate bottles respectively.
- In the toxicity control, more than 25% biodegradation occurred within 14 days (40%, based on ThCO2). Therefore, the test item was assumed not to inhibit microbial activity.

Results with reference substance:

Sodium acetate was biodegraded for 86% after 14 days.

Table 1 CO2 production in the blank

Day	HCl (0.05 N) titrated (mL)		Produced CO2 (mL HCl)	Produced CO2 (mg)	Cumulative CO2 (mg)
	Ba(OH)2^1)	Blank (mean)
2	48.76	45.71	3.05	3.4	3.4
5	48.82	45.09	3.72	4.1	7.5
7	48.98	45.49	3.49	3.8	11.3
9	51.21	47.76	3.45	3.8	15.1
15	50.15	47.18	2.97	3.3	18.3
19	50.14	46.31	3.83	4.2	22.6
23	50.46	45.73	4.72	5.2	27.8
27	51.68	46.50	5.18	5.7	33.5
29^2)	51.27	46.78	4.49	4.9	38.4
29^2)	51.08	48.26	2.82	3.1	41.5
29^2)	50.72	50.05	0.67	0.7	42.2
^1): "Strength" of untreated 0.0125 M Ba(OH)2solution ^2): CO2measured on day 29 is actually part of CO2production of day 28, since microbial activity was ended on day 28 by addition of HCl.

Table 2 CO2 Production and Percentage Biodegradation of the Positive Control Item

Day	HCl (0.05 N) titrated (mL)		Produced CO2 (mL HCl)	Produced CO2 (mg)	Cumulative CO2 (mg)	Biodegradation^1) (%)
	Blank (mean)	Positive control
2	45.71	37.81	7.90	8.7	8.7	10
5	45.09	18.96	26.13	28.7	37.4	44
7	45.49	33.62	11.87	13.1	50.5	59
9	47.76	40.91	6.85	7.5	58.0	68
15^2)	47.18	33.37	13.81	15.2	73.2	86
^1): Calculated as the ratio between CO2produced (cumulative) and the ThCO2of sodium acetate: 85.6 mg CO2/2L. ^2): CO2measured on day 15 is actually part of CO2production of day 14, since microbial activity was ended on day 14 by addition of HCl.

Table 3 CO₂ Production and Percentage Biodegradation of the Test Item (Bottle A)

Day	HCl (0.05 N) titrated (mL)		Produced CO2 (mL HCl)	Produced CO2 (mg)	Cumulative CO2 (mg)	Biodegradation^1) (%)
	Blank (mean)	Bottle A
2	45.71	47.00	0.00	0.0	0.0	0
5	45.09	45.78	0.00	0.0	0.0	0
7	45.49	46.33	0.00	0.0	0.0	0
9	47.76	47.65	0.10	0.1	0.1	0
15	47.18	46.48	0.70	0.8	0.9	1
19	46.31	45.36	0.95	1.0	1.9	2
23	45.73	45.06	0.67	0.7	2.7	3
27	46.50	45.71	0.79	0.9	3.5	4
29^2)	46.78	44.75	2.03	2.2	5.8	7
29^2)	48.26	47.64	0.62	0.7	6.5	7
29^2)	50.05	49.66	0.39	0.4	6.9	8
^1): Calculated as the ratio between CO2produced (cumulative) and the ThCO2of the test item: 87.1 mg CO2/2L. ^2): CO2measured on day 29 is actually part of CO2production of day 28, since microbial activity was ended on day 28 by addition of HCl.

Table 4 CO₂ Production and Percentage Biodegradation of the Test Item (Bottle B)

Day	HCl(0.05 N) titrated (mL)		Produced CO2 (mL HCl)	Produced CO2 (mg)	Cumulative CO2 (mg)	Biodegradation^1) (%)
	Blank (mean)	Bottle A
2	45.71	47.60	0.00	0.0	0.0	0
5	45.09	46.13	0.00	0.0	0.0	0
7	45.49	47.38	0.00	0.0	0.0	0
9	47.76	48.14	0.00	0.0	0.0	0
15	47.18	47.31	0.00	0.0	0.0	0
19	46.31	46.80	0.00	0.0	0.0	0
23	45.73	47.03	0.00	0.0	0.0	0
27	46.50	47.21	0.00	0.0	0.0	0
29^2)	46.78	46.80	0.00	0.0	0.0	0
29^2)	48.26	48.96	0.00	0.0	0.0	0
29^2)	50.05	49.81	0.24	0.3	0.3	0
^1): Calculated as the ratio between CO2produced (cumulative) and the ThCO2of the test item: 87.1 mg CO2/2L. ^2): CO2measured on day 29 is actually part of CO2production of day 28, since microbial activity was ended on day 28 by addition of HCl.

Table 5 CO₂ Production and Percentage Biodegradation of the Toxicity Control

Day	HCl (0.05 N) titrated (mL)		Produced CO2 (mL HCl)	Produced CO2 (mg)	Cumulative CO2 (mg)	Biodegradation^1) (%)
	Blank (mean)	Toxicity control
2	45.71	41.63	4.08	4.5	4.5	3
5	45.09	22.43	22.66	24.9	29.4	17
7	45.49	35.04	10.45	11.5	40.9	24
9	47.76	39.44	8.32	9.1	50.0	29
15^2)	47.18	30.41	16.77	18.4	68.5	40
^1): Calculated as the ratio between CO2produced (cumulative) and the sum of the ThCO2of the test item and positive control: 172.7 mg CO2/2L (ThCO2test item: 87.1 mg CO2/2L + ThCO2sodium acetate: 85.6 mg CO2/2L). ^2): CO2measured on day 15 is actually part of CO2production of day 14, since microbial activity was ended on day 14 by addition of HCl.

Validity criteria fulfilled:

yes

Remarks:

See 'Any other information on results' section.

Interpretation of results:

not readily biodegradable

Conclusions:

TBEAES was not readily biodegradable under the conditions of the modified Sturm test, according to OECD 301B and GLP principles.

Executive summary:

In a Modified Sturm Test, according to OECD guideline 301 B and GLP principles, TBEAES DRY was assessed for its ''ready biodegradability'' potential. The test substance was tested in duplicate at a target concentration of 21 mg/L, corresponding to 12 mg TOC/L. The exposure period was 28 days. Two inoculum blanks, a positive control and a toxicity control were included. Since the test substance was well soluble in water, the test media were prepared using a stock solution of 1 g/L in Milli-RO water by dissolving 501.03 mg of the test substance in 500 mL water and stirring for 90 minutes.

CO2 measurements showed that the test substances biodegraded for 0% and 8%, in the duplicate bottles measured. Because the criterion for ready biodegredability was not met, TBEAES DRY was concluded to be not readily biodegradable under the conditions of this test.

The test substance was found not to inhibit microbial activity and all validity criteria were met, thus the study was considered to be valid.

Description of key information

Not readily biodegradable under the conditions of a Modified Sturm Test, according to OECD guideline 301 B and GLP principles.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Type of water:

freshwater

Additional information

In a Modified Sturm Test, according to OECD guideline 301 B and GLP principles, TBEAES DRY was assessed for its ''ready biodegradability'' potential. The test substance was tested in duplicate at a target concentration of 21 mg/L, corresponding to 12 mg TOC/L. The exposure period was 28 days. Two inoculum blanks, a positive control and a toxicity control were included. Since the test substance was well soluble in water, the test media were prepared using a stock solution of 1 g/L in Milli-RO water by dissolving 501.03 mg of the test substance in 500 mL water and stirring for 90 minutes.

CO2 measurements showed that the test substances biodegraded for 0% and 8%, in the duplicate bottles measured. Because the criterion for ready biodegredability was not met, TBEAES DRY was concluded to be not readily biodegradable under the conditions of this test.

The test substance was found not to inhibit microbial activity and all validity criteria were met, thus the study was considered to be valid.