Docosyltrimethylammonium methyl sulphate

Biodegradation in water and sediment: simulation tests

Administrative data

Endpoint:

biodegradation in water: sewage treatment simulation testing

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

2009-04-17 to 2009-06-11

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: According to OECD 303A Guideline and GLP. Justification for read-across see chemical safety report chapter 1.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 303 A (Simulation Test - Aerobic Sewage Treatment. A: Activated Sludge Units)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Quaternary ammonium compounds, C20-22-alkyltrimethyl, chlorides

EC Number:

271-756-9

EC Name:

Quaternary ammonium compounds, C20-22-alkyltrimethyl, chlorides

Cas Number:

68607-24-9

IUPAC Name:

68607-24-9

Radiolabelling:

no

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Activated sludge from the sewage plant at Hildesheim is well suited as it comprises mostly municipal sewage and hardly industrial chemical waste (industrial chemical waste: 30 - 33 %, referring to BOD).

- Preparation of inoculum for exposure: The activated sludge was maintained in an aerobic condition by aeration at room temperature until it was used. Calculated starting concentration of dry matter was about 3 g/L.

Duration of test (contact time):

52 d

Initial test substance concentration

Initial conc.:

300 µg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

test mat. analysis

Details on study design:

TEST CONDITIONS
- Volume of test solution/treatment: Cstock = 3 g/L in methanol, freshly prepared at least every 7 days. Dosed at a constant rate of 0.05 L/h, corresponding to 41 µg C20-fraction of C20/22-ATQ trocken/L and 243 µg C22-fraction of C20/22-ATQ trocken/L
- Composition of medium: Organic medium: Mixture of domestic sewage and synthetic sewage with 100 mg C/L
- Additional substrate: Synthetic sewage was prepared according to OECD 303 A and used for DOC adjustment of domestic sewage if necessary.
- Test temperature: 20 - 25 °C
- pH: 7.5 +/- 0.5 (no adjustments were made)
- pH adjusted: no
- Suspended solids concentration: Initial dry weight content: 3.0 +/- 0.5 g/L
- Continuous darkness: Low light conditions


TEST SYSTEM
- Apparatus: Activated sludge units consisting of an aeration vessel (3L) and a separator (2.5 L)
- Number of culture flasks/concentration: 1
- Method used to create aerobic conditions: continuous aeration
- Measuring equipment:
Oxygen, pH-value, Multi 340 (WTW)
Temperature
Pumps Membrane piston pumps ProMinent® gamma/ 4-W
(PROMINENT DOSIERTECHNIK GMBH, Heidelberg)
Precision syringe pumps, KD SCIENTIFIC and HARVARDAPPARATUS
Aeration Membrane pump MP500 (BEHR LABOR-TECHNIK)
DOC Multi N/C 3000 ANALYTIK JENA AG

- Test performed in closed vessels due to significant volatility of test substance: No
- Test performed in open system: Yes


SAMPLING
- Sampling frequency:
Type and Frequency of Measurements
(exclusive test item analysis)

Parameter Frequency
Influent volumes 3x per week
Removed sludge volume Daily
DOC of the effluents Weekdays during acclimatisation, daily during steady state phase
DOC of the influent Every new batch
Oxygen concentration, temperature, pH value in the aeration vessel At least twice per week
Suspended solids Daily


- Sample storage before analysis: Samples were stored at -20 +/- 2 °C before preparation and at room temperature after sample preparation, if necessary.



CONTROL AND BLANK SYSTEM
- Inoculum blank: An activated sludge unit with methanol treatment (without test item) was used as control.
- Abiotic sterile control: No
- Toxicity control: No

Results and discussion

Test performance:

The system was started with the conditions described above.
- Set-up of the test units
- Inoculation with activated sludge
- Dosage of sewage (organic medium)
- Sludge adhering to the walls of the activated sludge units was resuspended
- After the system had stabilized and the removal of DOC of the sewage was efficient (> 80 %) the test item solution (control: methanol) was applied.
- Sampling and measurements as given above
- Calculation of ultimate biodegradation of the organic medium, elimination/adsorption and primary biodegradion of the test item
- Completion of the study after a sufficient degree of elimination and the plateau was reached (> 90 %).

% Degradation

% Degradation 1

% Degr.:

96

Parameter:

other: (C20 fraction) primary biodegradation

Sampling time:

52 d

Remarks on result:

other: median of all samples

% Degradation 2

% Degr.:

91

Parameter:

other: (C22 fraction) primary biodegradation

Sampling time:

52 d

Remarks on result:

other: median of all samples

Evaporation of parent compound:

no

Volatile metabolites:

no

Residues:

no

Any other information on results incl. tables

Influent and Effluent Concentration and Elimination of C20-fraction
                   of C20/22-ATQ trocken (exemplarily)

Study day	Day of test item application	Date	Influent concentration	Effluent concentration	Elimination
			[µg/L]	[µg/L]	[%]
3	0	20.04.09	42.19		¿
4	1	21.04.09	42.19	0.228	99.46
5	2	22.04.09	41.00	0.228	99.46
6	3	23.04.09	41.00	0.685	98.33
7	4	24.04.09	41.57	0.228	99.44
9	6	26.04.09	42.19	0.228	99.45
10	7	27.04.09	42.19	0.228	99.46
11	8	28.04.09	42.50	0.228	99.46
12	9	29.04.09	42.50	0.685	98.39
13	10	30.04.09	42.00	0.228	99.46
14	11	01.05.09	42.00	0.228	99.46
15	12	02.05.09	41.91	0.685	98.37
16	13	03.05.09	41.91	0.685	98.37
17	14	04.05.09	41.99	0.685	98.37
18	15	05.05.09	41.99	0.685	98.37
19	16	06.05.09	42.01	0.228	99.46
20	17	07.05.09	42.01	0.228	99.46
21	18	08.05.09	42.94	0.685	98.37
22	19	09.05.09	42.94	0.228	99.47
23	20	10.05.09	41.90	0.228	99.47
24	21	11.05.09	41.90	0.228	99.46
25	22	12.05.09	42.61	0.228	99.46
26	23	13.05.09	42.61	0.228	99.46
27	24	14.05.09	42.13	0.228	99.46
28	25	15.05.09	42.13	0.228	99.46
29	26	16.05.09	41.57	0.228	99.46
30	27	17.05.09	41.57	0.685	98.35
31	28	18.05.09	42.54	0.228	99.45
32	29	19.05.09	42.54	0.685	98.39
33	30	20.05.09	41.21	0.228	99.46
34	31	21.05.09	41.21	0.685	98.34
35	32	22.05.09	42.24	0.228	99.45
36	33	23.05.09	42.24	0.685	98.38
37	34	24.05.09	42.40	0.228	99.46

continued

Study day	Day of test item application	Date	Influent concentration	Effluent concentration	Elimination
			[µg/L]	[µg/L]	[%]
38	35	25.05.09	42.40	0.228	99.46
39	36	26.05.09	42.64	0.228	99.46
40	37	27.05.09	42.64	0.228	99.47
41	38	28.05.09	42.09	0.685	98.39
42	39	29.05.09	42.09	0.228	99.46
43	40	30.05.09	42.14	0.228	99.46
44	41	31.05.09	42.14	0.228	99.46
45	42	01.06.09	42.26	0.685	98.37
46	43	02.06.09	43.27	0.685	98.38
47	44	03.06.09	43.27	0.228	99.47
48	45	04.06.09	43.02	0.228	99.47
49	46	05.06.09	43.02	0.228	99.47
50	47	06.06.09	42.44	0.228	99.47
51	48	07.06.09	42.44	0.228	99.46
52	49	08.06.09	41.65	0.228	99.46
53	50	09.06.09	41.65	0.228	99.45
54	51	10.06.09	43.70	1.39^#	96.66
55	52	11.06.09	¿	0.228	99.48

Applicant's summary and conclusion

Validity criteria

Validity criteria fulfilled:

yes

Conclusions:

The elimination was 98.83 % for the C22 fraction and 99.11 % for the C20 fraction of the test substance C20/22 ATQ. The maximum primary biodegradation was 96 % for C20-fraction of C20/22-ATQ trocken and 91 % for C22-fraction of C20/22-ATQ trocken based on the median of all samples.

Executive summary:

The elimination and biodegradation of the test item C20/22 ATQ trocken in an activated sludge unit was determined over a test period (plateau phase) of 25 days according to OECD guideline 303 A. The study was conducted from 2009-04-17 to 2009-06-19 at the Dr.U.Noack-Laboratorien, 31157 Sarstedt, Germany . The definite exposure phase was from 2009-04-20 to 2009-06-11.

During acclimatisation the activated sludge units were inoculated with activated sludge. The DOC elimination of the organic medium reached a degradation rate > 80 % already after 2 days. The dosage of the test item was started after an acclimatisation period of 3 days.

The nominal concentration of the test item stock solution was 3 g/L. The stock solution was dosed at a constant rate of 0.05 mL/h into the activated sludge unit, resulting in a nominal influent concentration of 300 µg/L corresponding to 41 µg C20-fraction of C20/22-ATQ trocken/L and 243 µg C22-fraction of C20/22-ATQ trocken/L. The influent concentration was corrected by the C20-fraction of C20/22-ATQ trocken and C22-fraction of C20/22-ATQ trocken concentration of the organic medium.

Specific analysis of C20/22 ATQ trocken was carried out via LC-MS/MS. The concentrations of C20-fraction of C20/22-ATQ trocken and C22-fraction of C20/22-ATQ trocken in the influent (organic medium and stock solution), effluent and activated sludge were determined. The LOQ for the organic medium was 30 µg/L C20/22 ATQ trocken corresponding to 4.11 µg/L C20-fraction of C20/22-ATQ trocken and 24.3 µg/L C22-fraction of C20/22-ATQ trocken. For activated sludge the LOQ was 55.6 µg C20/22 ATQ trocken/g DW corresponding to 7.62 µg/g for the C20-fraction of C20/22-ATQ trocken and 45.0 µg/g for  the C22-fraction of C20/22-ATQ trocken.

The LOQ for the effluent was 15 µg/L C20/22 ATQ trocken corresponding to 2.06 µg/L C20-fraction of C20/22-ATQ trocken and 12.1 µg/L C22-fraction of C20/22-ATQ trocken. The effluent concentration was below the LOD or LOQ_S. The elimination was therefore calculated based on the LOD of 0.228 µg/L for C20-fraction of C20/22-ATQ trocken and 2.03 µg/L for C22-fraction of C20/22-ATQ trocken and on the LOQ_S of 0.685 µg/L for C20-fraction of C20/22-ATQ trocken and 4.05 µg/L for C22-fraction of C20/22-ATQ trocken.

One day after starting the application of C20/22 ATQ trocken the elimination was already > 99 % for C20-fraction of C20/22-ATQ trocken and C22-fraction of C20/22-ATQ trocken. C20/22 ATQ trocken adsorbed completely onto the activated sludge. Furthermore, primary biodegradation started directly after starting the application of C20/22 ATQ trocken. For C20-fraction of C20/22-ATQ trocken the biodegradation was > 80 % already after 6 days. The biodegradation increased consistently and during the plateau phase, a primary biodegradation of 96 % was reached (median of all samples). For C22-fraction of C20/22-ATQ trocken the primary biodegradation reached 82 % on day 15 and during the plateau phase a primary biodegradation of 91 % was reached (median of all samples). The maximum primary biodegradation was 98 % for C20-fraction of C20/22-ATQ trocken and 93 % for C22-fraction of C20/22-ATQ trocken (Table 2).

Table 1:    Statistical Evaluation of Influent Concentration and Elimination

	C20-fraction of C20/22-ATQ trocken		C22-fraction of C20/22-ATQ trocken
	Influent	Elimination	Influent	Elimination
	[µg/L]	[%]	[µg/L]	[%]
Range measured	41.0 - 43.7	96.66 - 99.48	243.0 - 255.2	95.14 - 99.20
Median	42.2	99.46	249.2	99.18
Mean	42.2	99.11	249.2	98.83
95 % CI	42.0 - 42.4	98.94 - 99.28	248.4 - 250.0	98.65- 99.01
Number of case n	52	52	52	52

CI = Confidence Interval

Table 2:     Statistical Evaluation on the Biodegradation for C20-fraction of C20/22-ATQ
                   trocken and C22-fraction of C20/22-ATQ trocken during the Plateau Phase

Biodegradation	C20-fraction of C20/22-ATQ trocken	C22-fraction of C20/22-ATQ trocken
	[%]	[%]
Range measured	94 - 98	87 - 93
Median	96	91
Mean	96.4	90.5
95 % CI	96.1 - 96.7	89.8 - 91.2
Number of case n	25	25

             CI = Confidence Interval

The validity criteria of the test are fulfilled according to the guideline.