Tris(2-methoxyethoxy)vinylsilane

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1993-10-11 to 1993-10-15

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Version / remarks:

Cited as Directive 92/69/EEC, C.1

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

Samples of the test media were taken for analysis at the start of the test and after 24 (fresh and old media), 48 (fresh medium), and 72 (fresh medium) hours .

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION

- Method: As the test substance has low water solubility, it was added to VE-water at 10.14 g/l and stirred for 18 hours. The resulting solution was filtered and used as the stock solution.

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

TEST ORGANISM

- Common name: Zebrafish

- Source: West aquarium, Bad Lauterberg, Germany

- Length at study initiation (length definition, mean, range and SD): 3.0 cm +/-0.5 cm

- Feeding during test: none

ACCLIMATION

- Acclimation period: at least 14 days

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

- Type and amount of food: TetraMin® at 1% of body weight

- Feeding frequency: Daily

- Health during acclimation (any mortality observed): The fish exhibit normal behaviour and are free from visible signs of disease at the start of the t
est.

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Hardness:

10.7ºdH

Test temperature:

20ºC

pH:

7.8 - 8.4

Dissolved oxygen:

7.4 - 8.9 mg/L

Salinity:

Not applicable

Nominal and measured concentrations:

Nominal concentrations: 0 (Control) and 100 mg/L.

The measured concentration of the test substance (as DOC) after 0, 24, 48, and 72 hours was determined to be 103, 114/106, 126, and 106 mg/l, respectively.  

Details on test conditions:

TEST SYSTEM

- Test vessel: 20 litre aquarium

- Type (delete if not applicable): open

- Aeration: Yes, continuous

- Renewal rate of test solution: daily

- No. of organisms per vessel: 10

- No. of vessels per concentration (replicates): 1

- No. of vessels per control (replicates): 1


TEST MEDIUM / WATER PARAMETERS

- Source/preparation of dilution water: Potable water from Gelsenwasser AG


OTHER TEST CONDITIONS

- Adjustment of pH: No

- Photoperiod: 16 hours light, 8 hours dark


EFFECT PARAMETERS MEASURED: Daily mortalities


TEST CONCENTRATIONS

- Spacing factor for test concentrations: Limit test

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

- Mortality of control: 0

Reported statistics and error estimates:

There were no effects on mortality and therefore statistical analysis of the test results was not required.

Sublethal observations / clinical signs:

There were no mortalities in the Control or the treated media

Validity criteria fulfilled:

yes

Conclusions:

A 96-hour LC50 value of >100 mg/L and NOEC of =100 mg/L have been determined for the effects of the test substance on mortality of Brachydanio rerio (new name: Danio rerio), 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 LC50 >38 mg/L and NOEC =38 mg/L when expressed in terms of the silanol hydrolysis product.

Description of key information

Short-term toxicity to fish: 96 hour LC₅₀ >100 mg/L (nominal – measured within 20% of nominal) (highest concentration tested) (EU method C.1). The LC₅₀ is equivalent to >38 mg/L when expressed in terms of the silanol hydrolysis product.

The reported 96 hour LC₅₀ for 2-methoxyethanol for freshwater and marine fish is 10,000 mg/L for Leopomis macrochirus.

Additional information

A 96-h LC₅₀ value of >100 mg/L (nominal – measured within 20% of nominal) (highest concentration tested) has been determined for the effects of tris(2-methoxyethoxy)(vinyl)silane on mortality of Brachydanio rerio (new name: Danio rerio). 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) * >100 mg/L = >38 mg/L.

The nominal concentration for the test media stock solution preparation was very high (>10 g/L) considering the water solubility of the parent substance (2.2 mg/L). However, the rapid hydrolysis of the parent substance produces vinylsilanetriol, which is very soluble in water, as well as 2 -methoxyethanol. The non-silanol hydrolysis product is likely to act as a solvent, therefore oligomerisation of vinylsilanetriol at the high stock solution concentration is unlikely. This study was assigned reliability 1 because it was a guideline study (EU Method C.1) conducted in accordance with GLP.

The results of a second less reliable test are also available. No effects on mobility of Leuciscus idus were observed at a concentration of 500 mg/L.

The reliability of the results from a third test could not be determined because there was insufficient information in the source.

A 96-hour LC₅₀of >10,000 mg/l (nominal) has been determined for the effects of 2-methoxyethanol on mortality ofLepomis macrochirus,in a reliable study(Dawson et al., 1975).

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