Triethoxy(methyl)silane

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1994-04-26 to 1994-04-30

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:

not specified

Details on sampling:

- Concentrations: 500 mg/L

- Sampling method: Samples of test media were taken from all treatments at the start and end of the first (0-24h) and third (48-72h) test periods.

- Sample storage conditions before analysis: refrigerated

Vehicle:

not specified

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION

- Method: A stock solution was prepared by mixing the substance overnight with dilution water used in the test

- Controls: Dilution water

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

TEST ORGANISM

- Common name: Zebrafish

- Source: Tropical Waters (Feltham, UK)

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

- Length at study initiation (length definition, mean, range and SD): 3.4 cm (3.1 - 3.7 cm)

- Weight at study initiation (mean and range, SD): 0.38 g (0.3 - 0.45 g)

- Feeding during test: None

ACCLIMATION

- Acclimation period: 12 days

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

- Type and amount of food: TetraMin® Tropical Flake

- Feeding frequency: dependent upon size and temperature

- Health during acclimation (any mortality observed): Cumulative mortality must no exceed 5% in the 7-day period prior to the test.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

40.8 - 41.3 mg/L

Test temperature:

20 - 21ºC

pH:

7.0 - 7.5

Dissolved oxygen:

62 - 100% ASV

Nominal and measured concentrations:

Nominal: Control, 31.25, 62.5, 125, 250 and 500 mg/L.

Measured concentrations in fresh media (excluding Control) at start of test: 27.2, 58.5, 119, 249 and 499 mg/L.

Measured concentrations in old media (excluding Control) after 24 h exposure: 30.7, 63.4, 124, 248 and 497 mg/L.

Measured concentrations in fresh media (excluding Control) at 48 h: 32, 64.6, 124, 241 and 490 mg/L.

Measured concentrations in old media (excluding Control) after 24 h exposure: 28.1, 59.9, 117, 232 and 492 mg/L.

Mean measured concentrations: 29.4, 61.5, 121, 242 and 494 mg/L.

Mean measured concentrations as a % of nominal: 94.1, 98.4, 96.6, 96.9 and 98.9.

Details on test conditions:

TEST SYSTEM

- Test vessel: Culture vessels

- Type: sealed

- Material: Glass

- Aeration: none

- Renewal rate of test solution (frequency): daily

- No. of organisms per vessel: 10

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

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

- Biomass loading rate: 0.38 g/L

TEST MEDIUM / WATER PARAMETERS

- Source/preparation of dilution water: Laboratory mains supply

- Chlorine: <0.1 mg/L (Total)

- Alkalinity: 14 mg/L CaCO3

- Conductivity: 128 μS/cm

- Culture medium different from test medium: no

- Intervals of water quality measurement:

OTHER TEST CONDITIONS

- Adjustment of pH: no

- Photoperiod: 16 h (light)/8 h (dark)

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :

TEST CONCENTRATIONS

- Spacing factor for test concentrations: 2.0

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 500 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

but exposure is to hydrolysis product

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

>= 500 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

but exposure is to hydrolysis product

Basis for effect:

mortality (fish)

Details on results:

- Behavioural abnormalities: At the end of the testfish exposed to the 250 mg/L nominal test concentration were showing mild behavioural effects and those exposed to 500 mg/L severe behavioural effects.

Reported statistics and error estimates:

There were no lethal effects at the highest test concentration and therefore statistical analysis of the results was not carried out.

Validity criteria fulfilled:

yes

Conclusions:

A 96-hour LC50 value of >500 mg/L and NOEC of ≥500 mg/L have been determined for the effects of the test substance on mortality of Brachydanio rerio based on nominal concentration of the substance. However it is likely that the test organisms were primarily exposed to the hydrolysis products of the substance.

Reference 2

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

Not reported

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

secondary literature

Principles of method if other than guideline:

No guideline specified.

GLP compliance:

not specified

Analytical monitoring:

not specified

Vehicle:

not specified

Details on test solutions:

no data

Test organisms (species):

Lepomis macrochirus

Details on test organisms:

no data

Test type:

not specified

Water media type:

freshwater

Remarks on exposure duration:

no data

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

not specified

Conc. based on:

test mat.

Remarks:

but exposure is to hydrolysis products

Basis for effect:

mortality (fish)

Conclusions:

An LC50 value of >1000 mg/L has been reported for the test substance to Lepomis macrochirus. The result is reported in a peer reviewed secondary source.. It is likely that the test organisms were exposed to hydrolysis products of the substance.

Reference 3

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

Not reported

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

secondary literature

Principles of method if other than guideline:

No guideline specified.

GLP compliance:

not specified

Analytical monitoring:

not specified

Vehicle:

not specified

Test organisms (species):

Fundulus heteroclitus

Test type:

not specified

Water media type:

not specified

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

not specified

Conc. based on:

other: hydrolysis products

Basis for effect:

mortality (fish)

Conclusions:

An LC50 value of >1000 mg/L has been reported for the test substance to Fundulus heteroclitus. The result is reported in a peer reviewed secondary source, however there is insufficient information to fully assess its reliability.

Reference 4

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

No reported

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

secondary literature

Principles of method if other than guideline:

No guideline specified.

GLP compliance:

not specified

Analytical monitoring:

not specified

Vehicle:

not specified

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

No data

Test type:

not specified

Water media type:

freshwater

Limit test:

no

Hardness:

no data

Test temperature:

no data

pH:

no data

Dissolved oxygen:

no data

Salinity:

no data

Nominal and measured concentrations:

no data

Details on test conditions:

no data

Reference substance (positive control):

not specified

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

400 mg/L

Nominal / measured:

not specified

Conc. based on:

test mat.

Remarks:

but exposure is to hydrolysis products

Basis for effect:

mortality (fish)

Reported statistics and error estimates:

Not reported

Conclusions:

An LC50 value of 400 mg/L has been reported for the test substance to Oncorhynchus mykiss. The result is reported in a peer reviewed secondary source. It is likely that the test organisms were exposed to hydrolysis products of the substance.

Reference 5

Endpoint:

short-term toxicity to fish

Type of information:

calculation (if not (Q)SAR)

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The result was obtained by an appropriate predictive method

Principles of method if other than guideline:

The ECOSAR ‘neutral organics’ QSARs for acute data have been applied and the effect concentrations calculated using log Kow and molar mass as input variables. An additional factor of *0.2 has been applied to the results.

The USEPA model ECOSAR was used as the basis for the estimation. This method is well-validated for ‘neutral organics’, i.e. those which act by a general narcotic mechanism, the potency of which is usually related to log Kow. Its scope is acute and long-term effects for the three standard trophic levels.
The method was validated for use with organosilicon compounds with a high weight percent of Si and limited or no additional functionality. Many of the reliable data for the category are limit values, therefore, the data were considered in terms of the range of the E(L)C50, in accordance with normal classification bands:    

E(L)C50 < 1 mg/l;
E(L)C50 in the range > 1 mg/l to 10 mg/l;
E(L)C50 in the range > 10 mg/l to 100 mg/l;
E(L)C50 > 100 mg/l.

In general ECOSAR predicted correctly for most substances for each trophic level. However, performance was improved significantly by application of a factor of 0.2 to each predicted value (expressed in mg/l). The organosilicon substances are slightly more toxic than the general ECOSAR ‘neutral organics’ regression lines, although still well within the range of each model. The factor of 0.2 is applicable to fish, Daphnia and algae, across the whole range of log Kowvalues. It is concluded that the acute effects of the substances in the sub-category can therefore be predicted from ECOSAR, with a minor modification.

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

10 000 mg/L

Conclusions:

A 96 h LC50 value of 10000 mg/L was obtained for the hydrolysis product of the submission substance using an appropriate calculation method. The results are considered to be reliable.

Description of key information

(96-hour) LC50: >500 mg/l mortality Danio rerio, reliability 1.
(96-hour) LC50: 10000 mg/l mortality, hydrolysis product (using an appropriate calculation method), reliability 2.

Additional information

A 96-hour LC50 value of >500 mg/l and NOEC of ≥500 mg/l have been determined for the effects of the test substance on mortality of Danio rerio (tested as Brachydanio rerio) based on nominal concentration of the substance. The study was conducted according to a standard guideline (EU Method C.1, Acute Toxicity for Fish) and to GLP and so was selected as key study (1994).

LC50 values in the range of 400 to >1000 mg/l are available from secondary literature (three studies) of lower reliability. However, as the substance rapidly hydrolyses (half-life of approximately 5.5 hours) to methylsilanetriol, it is very likely that the test organisms were primarily exposed to the hydrolysis product retained in the test media. A 96 hour LC50 of 10000 mg/l for fresh water fish was derived for the hydrolysis product using an appropriate calculation method (QSAR adapted from ECOSAR v1.00) for silicon substances (2011).