3-chloropropyltrimethoxysilane

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:

1993-06-18 to 1993-07-16

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test)

Version / remarks:

Cited as Directive 84/449/EEC, C.5

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): activated sludge from a communal sewer (Marl-Ost)

Duration of test (contact time):

28 d

Initial conc.:

20 mg/L

Based on:

test mat.

Initial conc.:

10 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS

- Test temperature: 21.2-24.2°C

TEST SYSTEM

- Number of culture flasks/concentration: Four flasks: Test suspension: two flasks, Inoculum blank: one flask, reference substance: one flask

SAMPLING

- Sampling frequency: 0, 3, 6, 11, 17, 20, 26, and 28 days


CONTROL AND BLANK SYSTEM

- Inoculum blank: yes

Reference substance:

benzoic acid, sodium salt

Remarks:

20 mg/l

Key result

Parameter:

% degradation (CO2 evolution)

Value:

84

Sampling time:

28 d

Remarks on result:

other: 20 mg/L

Key result

Parameter:

% degradation (CO2 evolution)

Value:

43

Sampling time:

28 d

Remarks on result:

other: 10 mg/L

Details on results:

Biodegradation of the test substance was not >60% within a 10-day window.

Results with reference substance:

Biodegradation of the reference substance was >60% within a 10-day window (61%) (74% after 28 days)

 Table 1: Total Inorganic Carbon (TIC) and % Biodegradation values

Type of suspension	Sample point (days)
	30 minutes		3		6		11		17			20		26		28
	TIC (mg/L)	% biodeg.	TIC (mg/L)	% biodeg	TIC (mg/L)	% biodeg	TIC (mg/L)	% biodeg		TIC (mg/L)	% biodeg	TIC (mg/L)	% biodeg	TIC (mg/L)	% biodeg	TIC (mg/L)	% biodeg
Blank – mean result	1.38	-	3.13	-	5.74	-	8.52	-		14.96	-	16.13	-	22.89	-	25.05	-
10 mg/L Test substance – mean result	1.15	-2	4.25	10	8.81	28	12.24	34		19.50	42	20.84	43	28.02	47	29.68	43
20 mg/L Test substance – mean result	1.29	0	8.86	26	14.45	40	19.14	49		30.15	70	31.28	70	42.40	90	43.40	84
Reference substance – mean result	1.19	-1	16.29	38	26.40	59	29.83	61		40.88	74	49.65	67	49.80	77	51.00	74

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

Biodegradation results of 43% (10mg/l) and 84% (20 mg/l) in 28 days were determined in a reliable study conducted according to an appropriate test protocol, and in compliance with GLP.

Description of key information

Biodegradation in water, screening tests: 43% (10 mg/L) in 28 days  (OECD 301B)

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Type of water:

freshwater

Additional information

In a study conducted according to OECD 301B (CO₂ evolution), biodegradation values of 43% (10 mg/L) and 84% (20 mg/L) in 28 days were obtained for the substance. The biodegradation rate at the lower test concentration is in accordance with the expected rate based on the assumption that the substance will hydrolyse within the timescale of the ready biodegradation study to form methanol and (3-chloropropyl)silanetriol. The biodegradation observed in the study is attributable to the biodegradation of the methanol hydrolysis product.

Methanol is readily biodegradable (OECD 2004).

No significant biodegradation is expected for the silanol hydrolysis product, (3-chloropropyl)silanetriol.

Reference:

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