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Ecotoxicological information

Short-term toxicity to fish

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Reference
Endpoint:
short-term toxicity to fish
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1994-09-26 to 1994-09-30
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
EU Method C.1 (Acute Toxicity for Fish)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Analytical monitoring:
yes
Details on sampling:
Samples of test medium were taken at the start of the test and then after 24 hours in the old medium prior to renewal. Samples of freshly prepared medium were taken again when the tst medium was renewed after 24, 48 and 72 hours.
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION

- Method: Five nominal test concentrations in the range 101-913 mg/l were prepared by diluting a 1000 mg/l stock solution. The stock solution was prepared by stirring for 18 h followed by filtration.
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:
11.3 ºdH
Test temperature:
20 - 21ºC
pH:
7.7 - 8.5
Dissolved oxygen:
60 - 102% ASV
Nominal and measured concentrations:
Nominal concentration: 1000 mg/L

Initial measured concentration in fresh medium at the start of the test: 823.3 mg/L

Measured concentration in old medium prior to renewal and after 24 h exposure: 687.5 mg/L

Measured concentration in fresh media prepared for renewal at 24, 48 and 72 h: 654.6, 731.6 and 774.1 mg/L

Mean measured cocentration over test: 746 mg/L
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:
LC50
Effect conc.:
> 746 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Remarks:
but exposure is to hydrolysis products
Basis for effect:
mortality
Duration:
96 h
Dose descriptor:
NOEC
Effect conc.:
>= 746 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Remarks:
but exposure is to hydrolysis products
Basis for effect:
mortality
Details on results:
- Mortality of control: 0
Reported statistics and error estimates:
There were no toxic effects observed in the test and there statistical analysis of the results was not undertaken.
Validity criteria fulfilled:
yes
Conclusions:
A 96-h LC50 value of >746 mg/L and NOEC of ≥746 mg/L have been determined for the effects of the test substance on mortality of Brachydanio rerio based on mean measured concentrations. It is likely that the test organisms were exposed to the hydrolysis products of the substance.

Description of key information

Short-term toxicity to fish: 96 hour LC50 >746 mg/l (mean measured DOC) (highest concentration tested) (EU Method C.1 (Acute Toxicity for Fish)), read-across from an analogous/structurally related substance, trimethoxy(propyl)silane (CAS 1067-25-0). The observations in this study are attributed to the exposure of test organisms to the hydrolysis products in the test system.

Key value for chemical safety assessment

Additional information

There are no reliable short-term fish toxicity data available for trichloro(propyl)silane (CAS 141-57-1), therefore good quality data for an appropriate structural analogue, trimethoxy(propyl)silane (CAS 1067-25-0), have been read across. Both substances share the same silanol hydrolysis product, propylsilanetriol. The other hydrolysis products are hydrochloric acid and methanol, respectively. In the test with trimethoxy(propyl)silane (CAS 1067-25-0), the observations are attributed to the exposure of test organisms to propylsilanetriol in the test system. There is no basis to expect that methanol significantly influenced the results of the test. The toxicity of methanol is discussed further in the ecotoxicological information overview endpoint summary (additional information).

 

A 96-hour LC50 value of >746 mg/l (mean measured DOC) (highest concentration tested) have been determined for the effects of trimethoxy(propyl)silane (CAS 1067-25-0) on mortality of Brachydanio rerio. In view of the test media preparation method and exposure regime it is likely that the test organisms were exposed predominantly to the hydrolysis products of the tested substance. The test concentrations are reported in terms of DOC and are therefore not further adjusted in terms of concentration of parent corrected to concentration of silanol.

 

Above a concentration of approximately 1000 mg/l, dimeric / oligomeric, cyclic or cross-linked condensation products could potentially form over time in the aqueous test media. No evidence of undissolved material (parent substance or precipitated products) is indicated in the study report for this test. 

 

Refer to the discussion in the Section 6 endpoint summary (Section 7.0 of CSR) for further discussion of the approach to chemical safety assessment for this registration substance, and justification for read-across used.