N-methyl-3-(trimethoxysilyl)propylamine

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

12 Aug - 09 Sep 1993

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP guideline study with acceptable restrictions.

Qualifier:

according to guideline

Guideline:

EU Method C.4-A (Determination of the "Ready" Biodegradability - Dissolved Organic Carbon (DOC) Die-Away Test)

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: The inoculum was obtained from the sewage treatment plant Marl-East, Germany
- Preparation of the inoculum: the inoculum was centrifuged for 15 min at 3000 rpm. The remainder was discarded and the slime re-suspended in a mineral medium (wash). After another centrifugation step (15 min at 3000 rpm) followed by re-suspension of the slime, the final concentration was 5.6 g dw/L
- Concentration of sludge: 5.6 g dw/L
- Initial cell/biomass concentration: 26.8 mg/L
- Water filtered: no

Duration of test (contact time):

28 d

Initial conc.:

8.95 mg/L

Based on:

DOC

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

TEST CONDITIONS
- Composition of medium:
The test solutions were prepared as follows:
Solution A: 8.5 g KH2PO4/L
21.75 g KH2PO4/L
33.3 g Na2HPO4 x 2 H2O/L
20.0 g (NH4)Cl/L
Solution B: 22.5 g MgSO4 x 7 H2O/L
Solution C: 27.5 g CaCl2/L
Solution D: 0.25 g FeCl3 x 6 H2O
The specimen suspension, corresponding to a dry weight of 26.8 mg/L was added to three 2 L containers and filled with 1.5 L VE water. 20 mL of nutrient solution A and 2 mL initial nutrient solution B-D were added. The containers from which the test- or control solutions are to be filled received 42 mL test- or 38 mL control substance. The median material concentration was 8.95 mg DOC/L in the test solution, or 10.9 mg DOC/L in the control solutions. Containers were filled to two litres with VE water. 900 mL of this solution was placed into each 2000 mL Erlenmeyer flask.
- Test temperature: 21.8 - 22.2 °C

TEST SYSTEM
- Culturing apparatus: 2000 mL Erlenmeyer flasks with loose closure of aluminium foil
- Number of culture flasks/concentration: 2
- Measuring equipment: Shimadzu infrared DOC analyzer T 500

SAMPLING
- Sampling frequency: On days 0, 7, 14, 21, 27 and 28
- Sampling method: Shimadzu infrared DOC analyzer T 500 (double determination of oxygen-enriched and de-gassed samples, membrane filter with pore size od 0.2 µm)

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Reference substance: yes
- Abiotic sterile control: no
- Toxicity control: no

Reference substance:

benzoic acid, sodium salt

Key result

Parameter:

% degradation (DOC removal)

Value:

67

Sampling time:

28 d

Details on results:

The test substance was degraded to 67% after 28 days. The 10-day window was not met in which 70% of the test substance must be degraded. Therefore, the test substance is not readily biodegradable but is considered to be biodegradable.

Results with reference substance:

The reference substance sodium benzoate reached 98% biodegradation within 10 days and was completely degraded after 28 days.

Table 1: Degradation of the test substance.

Flask #	% DOC reduction after X days
	0	7	14	21	27	28
1	0	63	67	69	76	68
2	0	64	65	67	82	65
Median value	0	63	66	68	79	67

Table 2: Degradation of reference substance.

Flask #	% DOC reduction after X days
	0	7	14	21	27	28
1	0	100	98	96	99	100
2	0	99	98	100	100	100
Median value	-	-	-	-	-	-

Interpretation of results:

other: not readily biodegradable

Executive summary:

Materials and methods: The biodegradation potential of 3-Aminopropyl-triethoxysilan was tested in a DOC-Die Away test (EU Method C.4-A). The inoculum used during this experiment was collected from a primarily communal sewage treatment plant. The inoculum (final concentration per flask 26.8 mg/mL) was exposed for 28 days to the test substance, and blank and reference substance (sodium benzoate) controls were applied as well (in duplicate). The incubation temperature ranged from 21.8 to 22.2°C. Analytical DOC determinations were performed on days 0, 7, 14, 21, 27 and 28 and biodegradation rates calculated.

Results: The biodegradation of the test substance reached 63% within the first 7 days of experiment and a final degradation value of 67% on day 28. According to the criteria stated for this kind of test, 3-Aminopropyl-triethoxysilan can be considered not readily biodegradable (<70% biodegradation after 28 days). The reference substance attained 98% biodegradation within 10 days, being completely degraded by the end of the experiment.

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

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

Adequacy of study:

key study

Justification for type of information:

Please refer to the attached justification below and the overall justification for grouping of substances attached in IUCLID Section 13.

Reason / purpose for cross-reference:

read-across source

Key result

Parameter:

% degradation (DOC removal)

Value:

67

Sampling time:

28 d

Interpretation of results:

other: not readily biodegradable

Executive summary:

The biodegradation of the test substance reached 63% within the first 7 days of experiment and a final degradation value of 67% on day 28. According to the criteria stated for this kind of test, the substance is not considered readily biodegradable (<70% biodegradation after 28 days).

Description of key information

Not readily biodegradable (67% after 28 d, EU Method C.4 -A, DOC removal, read-across from CAS 919 -30 -2)

Key value for chemical safety assessment

Biodegradation in water:

inherently biodegradable

Additional information

There are no data on biodegradation for N-methyl-3-(trimethoxysilyl)propylamine (CAS 3069-25-8). In accordance with Regulation (EC) No. 1907/2006 Annex XI, 1.5 “Grouping of substances and read across” and in accordance with the Read across assessment framework (RAAF, ECHA 2017) a read across from the analogue substance 3-aminopropyltriethoxysilane (CAS 919-30-2) has been applied to support the environmental hazard assessment of N-methyl-3-(trimethoxysilyl)propylamine (CAS 3069-25-8). Details on read across justifications can be found in the attached justification in the respective target entry and in the overall justification for grouping of substances attached in IUCLID Section 13.

The available study (1994) investigating the biodegradation of the analogue substance 3-aminopropyltriethoxysilane (CAS 919-30-2) was conducted according to EU Method C4.A Dissolved organic carbon (DOC) Die-away test (92/69/EEC), under GLP conditions. The inoculum (non-adapted activated sludge from a sewage treatment plant) was exposed for 28 days to the test substance and biodegradation was calculated based on DOC removal measurements. At the end of the experiment, the substance reached a biodegradation value of 67% and therefore, is not considered as readily biodegradable. However, considering that within 7 days the biodegradation value for the substance was already 63% and the final value was 67%, almost reaching the pass value of 70% for readily biodegradable substances, 3-aminopropyltriethoxysilane can be regarded as moderately biodegradable.

Based on the results of the analogue substance, N-methyl-3-(trimethoxysilyl)propylamine (CAS 3069-25-8) is not assumed to be readily biodegradable.