N-[3-(trimethoxysilyl)propylcyclohexylamine]

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:

04 Jun - 02 Jul 2004

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

Version / remarks:

1992

Qualifier:

according to guideline

Guideline:

EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)

Version / remarks:

1992

GLP compliance:

yes (incl. QA statement)

Remarks:

Hessisches Ministerium für Umwelt, Landwirtschaft und Forsten, Wiesbaden, Germany

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: sewage plant Groß-Zimmern, Germany
- Laboratory culture: no
- Preparation of inoculum for exposure: Activated sludge was washed by centrifugation and supernatant was decanted. The solid material was resuspended in tap water and again centrifuged. The procedure was repeated twice. An aliquot of the final sludge suspension was weighed, dried and the ratio of wet sludge to dry weight was determined. Aliquots of washed sludge suspension corresponding to 1.5 g dw/L were mixed with the test water and aerated until use.
- Concentration of sludge: 1.5 g dw/L
- Water filtered: no

Duration of test (contact time):

28 d

Initial conc.:

25 other: mg test item in 244 mL final volume

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: according to the guideline
- Solubilising agent (type and concentration if used): not used
- Test temperature: 21.5 - 21.8 °C
- pH: 7.5 - 7.8 (pH was measured in all flasks at the start and end of the test)
- pH adjusted: no
- Suspended solids concentration: 30 mg suspended solids/L
- Continuous darkness: yes
- Other: continuous stirring

TEST SYSTEM
- Culturing apparatus: test flasks containing a volume of 500 mL
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: Sludge suspension mixed with the test water was aerated until use.
- Measuring equipment: manometric test system with test flasks
- Test performed in open system: no

SAMPLING
- Sampling frequency: continously
- Sampling method: Consumption of oxygen was determined by measuring the change of pressure in the flasks.
- Details of trap for CO2 and volatile organics if used: Evolved carbon dioxide was absorbed in an aqueous solution (45%) of potassium hydroxide.
- Other: Temperature was measured each working day in the climatic chamber.

CONTROL AND BLANK SYSTEM
- Inoculum control: 2 replicates (30 mg suspended solids/L + test water)
- Abiotic control: 1 replicate (25.4 mg sterile filtered test item + test water)
- Toxicity control: 1 replicate (25.1 mg test item + 25.2 mg aniline + 30 mg activated sludge/L)
- Procedure control: 1 replicate (25.8 mg aniline + 30 mg suspended solids/L + test water)

Reference substance:

aniline

Parameter:

% degradation (O2 consumption)

Value:

29

Sampling time:

28 d

Remarks on result:

other: based on ThODNH4

Details on results:

In the toxicity control containing both, the test item and the reference item aniline, 48% biodegradation was noted within 14 d and 48% biodegradation after 28 d based on ThODNO3. Based on ThODNH4 the degradation was 57% after 14 d and 58% after 28 d. Therefore the test item is not considered inhibitory on the activated sludge microorganisms (degradation > 25% within 14 d).

Results with reference substance:

The reference item aniline was degraded to 72% after 14 d and 79% after 28 d based on ThODNO3 or 93% and 101% after 14 and 28 d respectively based on ThODNH4. This confirms the suitability of the used activated sludge inoculum.

BIOLOGICAL RESULTS:

Table 1: % biodegradation (BOD/ThODNH4) of test item, Aniline and toxicity control

Time (d)	% Biodegradation
	Test item 1	Test item 2	Aniline	Tox. Control
1	10	6	0	4
2	14	10	0	11
3	15	11	-1	42
4	19	19	-1	49
5	20	18	10	51
6	19	19	64	53
7	20	20	67	53
8	21	19	72	54
9	23	21	78	55
10	23	21	86	56
11	23	21	90	56
12	24	22	91	56
13	24	22	93	56
14	24	22	93	57
15	24	24	95	57
16	22	22	93	56
17	24	22	95	57
18	24	22	95	57
19	25	21	94	57
20	25	21	96	57
21	27	23	97	57
22	25	21	96	56
23	25	23	97	56
24	27	23	99	56
25	27	25	99	58
26	30	25	99	58
27	30	25	101	58
28	30	27	101	58

VALIDITY CRITERIA:

Table 1: Validity criteria for OECD 301.

Criterion from the guideline	Outcome	Validity criterion fulfilled
Difference of extremes of replicate values of the removal of the test chemical at the plateau, at the end of the test or at the end of the 10-d window, as appropriate, is less than 20%.	Difference of duplicate values was < 20%	yes
Percentage degradation of the reference compound has reached the pass levels by day 14.	Reached the pass level within 6 d	yes
The oxygen uptake of the inoculum blank is normally 20-30 mg O2/L and should not be greater than 60 mg/L in 28 days.	oxygen uptake of the inoculum blank was 28 mg O2/L	yes
The toxicity control should degrade to at least 35% (based on DOC) or at least 25% (based on ThOD or ThCO2) within 14 d.	Biodegradation on day 14 was 57% (based on ThODNH4)	yes

Validity criteria fulfilled:

yes

Remarks:

For further details please refer to “Any other information on results incl. tables”.

Interpretation of results:

not readily biodegradable

Conclusions:

The test item was found to be biodegradable by an average of 29% of ThODNH4 under the test conditions (OECD 301F) within 28 d. Therefore the substance is not readily biodegradable.

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

Parameter:

% degradation (O2 consumption)

Value:

29

Sampling time:

28 d

Remarks on result:

other: based on ThoDNH4

Interpretation of results:

not readily biodegradable

Description of key information

Not readily biodegradable (29% within 28 d taking nitrification into account, OECD 301F) based on read across from CAS 27445-54-1.

Additional information

Data on the biodegradability of N-[3-(trimethoxysilyl)propylcyclohexylamine] (CAS 3068-78-8) are not available. 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 substanceN-{[Diethoxy(methyl)silyl]methyl}cyclohexanamine (CAS 27445-54-1)has been performed in order to gain information on the biodegradation potential of the target substance. Details on the read-across justification 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.

In the test investigating the biodegradation of the source substance according to OECD 301F and GLP standards (2004), non-adapted activated sludge was exposed for 28 d to the test item. 29% biodegradation was recorded after 28 days based on ThOD-NH4. Since the biodegradation did not reach the pass level of 60% the substance is not considered readily biodegradable under the test conditions.

Based on the results from the analogue substance, the target substance N-[3-(trimethoxysilyl)propylcyclohexylamine] (CAS 3068-78-8) is not considered readily biodegradable.