N,N,N,2,2,6,6-heptamethylpiperidin-4-aminium chloride

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

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

Adequacy of study:

other information

Study period:

2018-04-20 to 2019-01-31

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Cross-reference

Reason / purpose for cross-reference:

read-across source

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2019

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

(1992)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

[2,2,6,6-tetramethyl-4-(trimethylazaniumyl)piperidin-1-yl]oxidanyl chloride

EC Number:

814-375-0

Cas Number:

67036-09-3

Molecular formula:

C12H26N2OCl

IUPAC Name:

[2,2,6,6-tetramethyl-4-(trimethylazaniumyl)piperidin-1-yl]oxidanyl chloride

Test material form:

solid

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Activated sludge from a municipal waste water treatment plant in Germany, which predominantely treats domestic sewage. The activated sludge is collected from aeration tank.
- Storage conditions: kept under aerobic conditions between sampling and inoculation.
- Preparation of inoculum for exposure: not pre-adapted or altered prior to testing.
- Concentration of sludge: Concentration of 30 mg/L in the mineral media

Duration of test (contact time):

28 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

14 other: mg carbon/L

Based on:

ThCO2

Remarks:

nominal concentration

Initial test substance concentration 2

Initial conc.:

24 mg/L

Based on:

test mat.

Initial test substance concentration 3

Initial conc.:

35.9 other: mg/test vessel

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: mineral salts medium
- Additional substrate: no
- Solubilising agent: no
- Test temperature: 21.95 - 25.78 °C
- pH: 7.4 +/- 0.2
- pH adjusted: yes
- Aeration of dilution water: Vessels will be sealed and aerated with CO2-free air overnight before beginning of the study.
- Suspended solids concentration: 30 mg/L in the test vessels
- Continuous darkness: diffuse light conditions of low intensity.
- Other: Test vessels were permanently stirred by magnetic stirres during study period.

TEST SYSTEM
- Culturing apparatus: Test vessel 2 L glass bottles. Test volume 1500 mL.
- Number of culture flasks/concentration: two replicates per group (Test item group, Reference control group, Inoculum control group), toxicity control group one replicate
- Method used to create aerobic conditions: sparged with CO2-free air.
- Measuring equipment: trap vessel with barium hydroxide
- Test performed in closed vessels: sealed vessels
- Details of trap for CO2 and volatile organics if used: Trap vessels with barium hydroxide. At intervals the first trap was disconnected for titration. The other trap vessels moved up one position.


SAMPLING
- Sampling frequency: CO2 measurment intervals not longer than 5 days. 11 sampling time points during the study period.
- Sampling method: CO2 trap vessels

CONTROL AND BLANK SYSTEM
- Inoculum blank: only inoculum
- Reference control: reference item and inoculum
- Toxicity control: test item, reference item and inoculum

Reference substance

Reference substance:

benzoic acid, sodium salt

Remarks:

25 mg/L of the test item/test vessel (50 mg/L, corresponds to 10 mg carbon/L).

Results and discussion

% Degradation

Key result

Parameter:

% degradation (CO2 evolution)

Value:

0

Sampling time:

28 d

Details on results:

The CO2 concentrations in the test vessels were measured at time intervals throughout the 28 day testing period. All treatments were corrected by the mean value of the inoculum controls and the biochemical carbon dioxide yield was calculated. The percent degradation was derived from the ThCO2, divided by the theoretical production.
The test item showed a degradation of 0% while the reference item amounted to a degradation of 115 % after 28 days. In the toxicity control, biodegradation amounted to ≥ 34 % within 14 days. Thus, according to the test guidelines, the test item had no significant inhibitory effect on activated sludge microorganisms at the tested concentration due to a biodegradation > 25 %. Measured pH values were in the range between 7.39 and 8.03.

BOD5 / COD results

Results with reference substance:

Sodium benzote: Biodegradation after 28 days: 115%

Any other information on results incl. tables

Percentage of degradation

Degradation^1[%]
Time [days]	Test Item		Reference Control		ToxicityControl
	Replicate 1	Replicate 2	Replicate 1	Replicate 2	-
1	0	0	12	13	6
4	0	0	33	45	18
6	0	0	52	63	25
8	0	0	64	73	27
11	0	0	83	90	34
15	0	0	91	96	37
18	0	0	98	102	39
22	0	0	103	104	40
25	0	0	110	112	43
28	0	0	114	116	44
29	0	0	114	117	45
29	0	0	113	115	44
29	0	0	113	116	44
Mean (28 days)	0		115		-

¹Corrected for the mean oxygen uptake of the inoculum controls

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

Validity criteria (replicate variability >20%, reference compound reach 60% after 14 d, inoculum blank <70 mg/L after 28 d, pH at 7.4) were met.

Interpretation of results:

not readily biodegradable

Conclusions:

The ready biodegradability of TMA-TEMPO was assessed with the CO2 Evolution Test according to OECD Guideline 301 B. TMA-TEMPO was tested at a nominal concentration of 14 mg Carbon/L. The following biodegradation was determined at the end of the 28-d period: TMA-TEMPO: 0 % and Sodium benzoate: 115 %. Since the pass value of > 60 % was not reached within 28 days TMA-TEMPO cannot be considered to be readily biodegradable under the tested conditions according to OECD guideline 301 B. TMA-TEMPO had no significant inhibitory effect on activated sludge microorganisms at the tested concentrations.