Trimethoxypropylsilane

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:

1994-09-26 to 1994-09-30

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)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 1000 mg/L
- Sampling method: 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 test medium was renewed after 24, 48 and 72 hours.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: A stock solution of 1 g test substance in 1 L drinking water was prepared by mixing for 18 h followed by filtration. No further details were provided on the filtration step.
- Other: The test medium was freshly prepared from the stock solution every day.

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: 3.0 cm +/-0.5 cm
- Feeding during test: None

METHOD OF BREEDING
- Maintenance of the brood fish: The fish were held in 200 L stoneware or 300 L glassware tanks filled with dechlorinated drinking water at 20 °C ± 2 °C in a flow-through system.
- Type and amount of food: TetraMin® at 1% of body weight
- Feeding frequency: Daily
- Mortality: Mortality was ≤ 5% 7 d before test start.

ACCLIMATION
- Acclimation period: At least 14 days quarantine
- Acclimation conditions (same as test or not): Yes
- Treatment: The fish are treated with malachite green 3 times per week during the 2-week quarantine period.
- Health during acclimation: The fish exhibit normal behaviour and are free from visible signs of disease at the start of the test.

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: Control, 1000 mg/l
Measured concentration: Control, 746 mg/L (mean measured concentration of the freshly prepared test media)
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

Details on test conditions:

TEST SYSTEM
- Test vessel: 20 L aquarium
- Type: 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
- Volume: 10 L

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. (arithm. mean)

Conc. based on:

test mat.

Remarks:

but exposure is to hydrolysis products

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

>= 746 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Remarks:

but exposure is to hydrolysis products

Basis for effect:

mortality (fish)

Details on results:

- Mortality of control: 0

Reported statistics and error estimates:

There were no toxic effects observed in the test and statistical analysis of the results was not undertaken.

Sublethal observations / clinical signs:

ANALYTICAL RESULTS

The stability check resulted in deviations in concentration of < 20%. Therefore, it is concluded that neither the parent substance nor the hydrolysis products are biodegraded or volatilized and the results were based on the arithmetic mean measured concentration.

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

LC50 (96 h) > 746 mg/L (arithmetic mean measured, EU method C1, B. rerio, RL 1), equivalent to 554 mg/L when expressed in terms of the silanol hydrolysis product

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Dose descriptor:

LC50

Remarks:

96 h

Effect concentration:

> 554 mg/L

Additional information

A 96 hr LC₅₀ of >746 mg/l (EU Method C.1 (Acute Toxicity for Fish) was determined for the effects of trimethoxypropylsilane on mortality of Brachydanio rerio based on mean measured concentrations.

However as the substance rapidly hydrolyses (half-life approximately 2.6 hours) to propysilanetriol, it is therefore likely that the test organisms were primarily exposed to hydrolysis product retained in the test media.