Tris(2-methoxyethoxy)vinylsilane

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1993-05-19 to 1993-05-21

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

Cited as Directive 84/449/EEC, C.2 (Acute toxicity for Daphnia)

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

The Dissolved Organic Carbon (DOC) concentration of the stock solution used to prepare the test media was determined.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION

- Method: The test substance was added to water at 1 g/L and stirred for 18 hours. After that the solution was filtered and the DOC determined. 

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM

- Common name: Daphnia magna

- Strain: Clone 5

- Source: Stock culture

- Age at study initiation (mean and range, SD): <24 h

- Method of breeding: Parthenogenetic reproduction

- Feeding during test: None

ACCLIMATION

- Acclimation conditions (same as test or not): yes

- Type and amount of food: sufficient to be consumed each day leaving no residue

- Feeding frequency: daily

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

The sum of the Ca2+ and Mg2+ ions was 2.5 mmol

Test temperature:

20 +/-1ºC

pH:

7.0 - 7.3

Dissolved oxygen:

6.6 - 7.9

Salinity:

Not applicability

Nominal and measured concentrations:

Nominal concentrations (calculated from measured DOC concentration in the stock solution (522 mg/L; equivalent to 1107 mg/L of test substance): 0 (Control), 33.2, 66.4, 110.7, 188.2, 332.1, 575.6, and 996.3 mg/L

Details on test conditions:

TEST SYSTEM

- Test vessel:

- Type: open

- Material, size, headspace, fill volume: glass cylinder containing 10 ml of test medium

- Aeration: none

- No. of organisms per vessel: 5

- No. of vessels per concentration (replicates): 4

- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS

- Source/preparation of dilution water: Synthetic water was used for this test, which consisted of the following:
CaCl2 x 2 H2O at 294 mg/l
MgSO4 x 7 H2O at 113 mg/l
NaHCO3 at 63 mg/l
KCl at 5.5 mg/l  

- Intervals of water quality measurement: end of test

OTHER TEST CONDITIONS

- Photoperiod: Dark

EFFECT PARAMETERS MEASURED: Immobilization after 24 and 48 h exposure

TEST CONCENTRATIONS

- Spacing factor for test concentrations: 1.7 - 2.0

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

111 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

314 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 246 - 400

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

996 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

612 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 463-809

Details on results:

- Immobilisation of control: 0

Results with reference substance (positive control):

- 24-hour EC50: >0.90, <1.9 mg/L

Reported statistics and error estimates:

EC50 values and their 95% confidence intervals were determined by Probit Analysis

Table 1. Test results

Nominal test substance concentration (mg/L)	Mean percentage immobilisation after 24 hours	Mean percentage immobilisation after 48 hours
0 (Control)	0	0
33.2	0	5
66.4	0	5
110.7	0	0
188.2	5	20
332.1	10	60
575.6	40	80
996.3	85	100

Validity criteria fulfilled:

yes

Conclusions:

A 48-hour EC50 value of 314 mg/L and NOEC of =111 mg/L have been determined for the effects of the test substance on mobility of Daphnia magna, based on nominal concentrations. Due to the rapid hydrolysis half life of the substance. is likely that the test organisms were primarily exposed to the hydrolysis products of the substance. These results are equivalent to EC50 119 mg/L and NOEC =42 mg/L when expressed in terms of the silanol hydrolysis product.

Description of key information

Short-term toxicity to aquatic invertebrates: 48 hour EC₅₀ 314 mg/L (nominal) (EU method C.2). The EC₅₀ is equivalent to 119 mg/L when expressed in terms of the silanol hydrolysis product.

The reported 48 hour EC₅₀ for 2-methoxyethanol for freshwater invertebrates is 9400 mg/L for the reproduction of Brachionus sp. (rotifer).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

119 mg/L

Additional information

A 48-h EC₅₀ value of 314 mg/L (nominal) has been determined for the effects of tris(2-methoxyethoxy)(vinyl)silane on mobility of Daphnia magna. In view of the test media preparation method/exposure regime it is likely that the test organisms were exposed predominantly to the hydrolysis products of the tested substance.

The results may be expressed in terms of concentration of the hydrolysis product, vinylsilanetriol, by applying a molecular weight correction: (MW of silanol = 106.15 / MW of parent = 280.40) * 314 mg/L = 119 mg/L.

This study was assigned a reliability score of 1 as it is a guideline study (EU Method C.2) and was conducted in accordance with GLP.

A 48-hour EC₅₀ of 9400 mg/l (nominal) has been determined for the effects of 2-methoxyethanol on the reproduction ofBrachionus sp.,in a reliable study (Devillers et al., 2002).

Refer to IUCLID Section 6 endpoint summary for further discussion of the approach to chemical safety assessment for this registration substance.