N-[3-(trimethoxysilyl)propyl]aniline

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:

2004-10-01 to 2004-12-08

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)

Deviations:

no

GLP compliance:

yes

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 municipal water treatment plant Breisgauer Bucht

- Preparation of inoculum for exposure: washed twice by settling the sludge, decanting supernant and re-suspending the sludge in aerated tap water

- Concentration of sludge: 30 mg per litre

- Water filtered: no

Duration of test (contact time):

28 d

Initial conc.:

45 other: mg / 1500 ml

Based on:

test mat.

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS

- Composition of medium: See below

- Test temperature: 20 - 22 °C

- Suspended solids concentration: 30 mg/L activated sludge

- Continuous darkness: no


TEST SYSTEM

- Number of culture flasks/concentration: 3

- Method used to create aerobic conditions: aerated until use

- Measuring equipment: Total carbon analyser TOC-5000A

- Details of trap for CO2 and volatile organics if used: Absorbtion in 0.2 M Sodium Hydroxide

SAMPLING

- Sampling frequency: Day 1, 4, 7, 11, 14, 21 and 28.

- Sampling method: TOC of 0.2 M NaOH trap analysed at intervals stated above.

- Sample storage before analysis: none

CONTROL AND BLANK SYSTEM

- Inoculum blank: no

- Abiotic sterile control: no

- Toxicity control: yes

STATISTICAL METHODS: not needed

Reference substance:

benzoic acid, sodium salt

Test performance:

The biodegradation of the test item was 24.7% within 28 days (after acidification). The test item didn't reach the criterion of a ready biodegradability (60% degradation, 10-d-window).

The reference compound reached the pass levels for ready biodegradability within 4 days.

The degradation in the toxicity control was 59.7 % within 14 days and 72 % within 28 days, so there was no inhibition of the inoculum caused by the test item.

The highest mean CO2-evolution of the blank flasks was 33.8 mg/L within 28 days.

The temperature range was 20 - 22 °C throughout the whole study. The aeration rate was in the tolerated range of 2.7 - 5.5 bubbles/second.

Parameter:

% degradation (CO2 evolution)

Value:

24.7

Sampling time:

28 d

Details on results:

See table 1

The reference compound reached the pass levels for ready biodegradability within 4 days.

Results with reference substance:

See table 1

Table 1.  Percentage biodegradation (% of ThCO₂) of test item, of benzoic acid, sodium salt and of the toxicity control

	Day	0	4	7	11	14	21	28	28*
% Deg	T1	0	14.8	20.2	23.1	21.8	30.4	22.9	21.7
	T2	0	15.3	18.5	21.7	24.1	24	24.7	18.8
	T3	0	13.2	17.5	23.1	28.5	24.2	29.6	33.7
% Deg	R1	0	71.6	82.6	84.5	91.8	101.2	91.1	101.1
	R2	0	66.2	78.1	86.6	96.2	102.4	91.5	105.5
	R3	0	65.1	75.5	78.3	92.7	92.5	93.1	102.4
% Deg	Toxicity control	0	39	46.4	54.3	59.7	67.7	64.5	72.4

T1 – T3 = Dynasylan 1189

R1 – R3 = benzoic acid, sodium salt

* After acidification

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

In a highly reliable test, the validity criteria of the test guideline were met. After correction of the mean BOD of the Innoculum controls after 28 days, a mean degradation rate of 24.7 % was found. The test item can therefore not be considered ready 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 (CO2 evolution)

Value:

24.7

Sampling time:

28 d

Description of key information

N-[3-(trimethoxysilyl)propyl]aniline CAS 3068-76-6 is not readily biodegradable based on read across from CAS  31024-56-3

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Additional information

Experimental data on the biodegradability of N-[3-(trimethoxysilyl)propyl]aniline (CAS 3068-76-6) are not available. Therefore, good quality data from the analogous substance N-[3-(trimethoxysilyl)propyl]butylamine (CAS 31024-56-3), have been read across. 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 (2004) investigating the biodegradation of the analogue substance N-[3-(trimethoxysilyl)propyl]butylamine CAS 31024-56-3 was conducted according to OECD guideline 301 B criteria and GLP standards. 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 CO2 evolution. At the end of the experiment, the substance reached a biodegradation of 24.7% and therefore, the read across substance is not readily biodegradable.

Based on the results of the analogue substance, N-[3-(trimethoxysilyl)propyl]aniline (CAS 3068-76-6) is not assumed to be readily biodegradable.

References:

OECD (2004): SIDS Initial Assessment Report for SIAM 19, Berlin, Germany, 18-20 October 2004, Methanol, CAS 67-56-1.