Triethoxy(vinyl)silane

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:

2001

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Qualifier:

according to guideline

Guideline:

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

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge : activated sludge from a wastewater treatment plant (ARA Ergolz II, Fullinsdorf, Switzerland) treating predominantly domestic wastewater.

- Preparation of inoculum for exposure: washed

- Concentration ofsludge: 30 mg/L

Duration of test (contact time):

28 d

Initial conc.:

104 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS

- Test temperature: 22°C

- pH: 7.4

- pH adjusted: yes

- Continuous darkness: yes

TEST SYSTEM

- Culturing apparatus: 500ml Erlenmeyer flasks

- Number of culture flasks/concentration: Eight: test suspension: two flasks, inoculum blank: two flasks, reference substance: two flasks, abiotic control: one flask, toxicity control: one flask

SAMPLING

- Sampling frequency: 0,1,2,4,5,6,7,8,9,11,12,13,14,15,16,17,18,19,20,21,22,23,25,26,27,28 days

CONTROL AND BLANK SYSTEM

- Inoculum blank: yes

- Abiotic sterile control: yes

- Toxicity control: yes

Reference substance:

benzoic acid, sodium salt

Parameter:

% degradation (O2 consumption)

Value:

51

Sampling time:

28 d

Details on results:

The test suspension did not achieve a biodegradation result of >60% of the ThOD in a 10-day window within the 28-day period of testing.

Biodegradation of the reference substance was >60% within 14 days (89%) (93% degradation in 28 days)

No degradation of the test suspension occurred in the abiotic control.

The biodegradation result in the toxicity control was >25% within 14 days (64%)

The biodegradation rate in the toxicity control showes a similar course of biodegradation as the two controls and within 14 days of exposure, a biodegradation of 64 % was observed. Thus, according to guideline the test item shows no inhibitory effect on activated sludge microorganisms up to a concentration of 100 mg/L.

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

Measured data was not available for triethoxy(vinyl)silane (CAS 78-08-0), therefore read across of data obtained for the comparable substance, trimethoxyvinylsilane (CAS 2768-02-7) was considered suitable. A biodegradation result of 51% in 28 days was determined in a reliable study conducted according to an appropriate test protocol, and in compliance with GLP.

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1993-06-18 to 1993-07-16

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The study was conducted according to an appropriate OECD test guideline, with acceptable restrictions. The restrictions were that the report does not provide an explanation for the discrepancy in the results.

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

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 communal sewer (Marl-Ost)

Duration of test (contact time):

28 d

Initial conc.:

19.93 mg/L

Based on:

test mat.

Initial conc.:

10.1 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: 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

Parameter:

% degradation (CO2 evolution)

Value:

123

Sampling time:

28 d

Remarks on result:

other: 10.1mg/L

Parameter:

% degradation (CO2 evolution)

Value:

64

Sampling time:

28 d

Remarks on result:

other: 19.93mg/L

Details on results:

Biodegradation of the reference substance was 93% after 28 days.

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

Measured data was not available for triethoxy(vinyl)silane (CAS 78-08-0). Data was read across from trimethoxyvinylsilane (CAS 2768-02-7). A biodegradation result of 123% (10.1mg/L) and 64% (19.93mg/L) in 28 days was determined in a reliable study conducted according to an appropriate test protocol, with acceptable restrictions. The restrictions were that the report does not provide an explanation for the discrepancy in the results.

Reference 3

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 overall summary (IUCLID Section 5.1) and attached justification for grouping in IUCLID Section 13

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Key result

Parameter:

% degradation (O2 consumption)

Value:

51

Sampling time:

28 d

Remarks on result:

other: RCC Ltd, 2001

Parameter:

% degradation (CO2 evolution)

Value:

64

Sampling time:

28 d

Remarks on result:

other: 19.93mg/L

Remarks:

Hüls AG, 1993

Description of key information

Not readily biodegradable (51% biodegradation in 28 days (-9% biodegradation after correction for methanol biodegradation), OECD Guideline 301 F; RA CAS No. 2768-02-7)

Key value for chemical safety assessment

Biodegradation in water:

not biodegradable

Type of water:

freshwater

Additional information

There is no data on ready biodegradability for the target substance triethoxy(vinyl)silane (CAS 78-08-0) available. Therefore, a read across to the analogue substance trimethoxy(vinyl)silane (CAS 2768-02-7) has been applied to support the environmental hazard assessment of triethoxy(vinyl)silane (CAS 78 -08 -0). The target substance triethoxy(vinyl)silane (CAS 78-08-0) hydrolyses within the timescale of a ready biodegradation test to form the hydrolysis products vinylsilanetriol and ethanol (DT50 = 0.9 h at pH 7 and 20 - 25 °C, QSAR). The read across source substance trimethoxy(vinyl)silane (CAS 2768-02-7) also rapidly hydrolyses in the aquatic environment (DT50 = 0.1 h at 20 -25 °C and pH 7, QSAR) to form the same silanol hydrolysis product as the target substance, vinylsilanetriol; the other hydrolysis products being methanol and ethanol, respectively, which are readily biodegradable (OECD SIDS, 2004; OECD SIDS 2004).

Details on the read across justification can be found in IUCLID Section 13. 

The available study investigating the biodegradation of the analogue substance trimethoxy(vinyl)silane (CAS No. 2768-02-7) was conducted according OECD guideline 301 F and EU Method C.4-D under GLP criteria. 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 O2 consumption. The biodegradation rate determined for trimethoxy(vinyl)silane in the study was 51% after 28 days. This biodegradation is due to the biodegradation of the methanol hydrolysis product. After taking into account the biodegradation of aloxy and acetoxy compounds, the corrected biodegradation of the source substance trimethoxy(vinyl)silane is -9% biodegradation after 28 days. Thus, the substance is not biodegradable according to the OECD criteria. Based on the results of the analogue substance, the hydrolysis product vinylsilanetriol of the target substance triethoxy(vinyl)silane (CAS 78-08-0) is not expexted to be readily biodegradable.

References:

OECD SIDS, 2004. Ethanol - SIDS Initial Assessment Report For SIAM 19, Berlin, Germany: UNEP Publications.

OECD SIDS, 2004. Methanol - SIDS Initial Assessment Report For SIAM 19, Berlin, Germany: UNEP Publications.