N-[3-(trimethoxysilyl)propyl]butylamine

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

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:

other: The study was conducted according to the appropriate OECD test guideline, and in compliance with GLP.

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:

other: 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.

Description of key information

24% in 28 d (CO2 evolution, OECD 301B)

Key value for chemical safety assessment

Biodegradation in water:

not biodegradable

Type of water:

freshwater

Additional information

One experimental study is available for the biodegradation of N-[3 -(trimethoxysilyl)propyl]butylamine (2004).

In a screening test according to OECD testing guideline 301 B and GLP, non-adapted activated sludge was exposed to a test item concentration of 45 mg in 1500 mL test medium for 28 d under aerobic conditions and CO2 evolution was followed. A reference compound and a toxicity control were run in parallel.

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

The validity criteria of the test guideline were met (Hydrotox, 2004). The test item can therefore not be considered ready biodegradable.