Triethoxy(methyl)silane

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1994-04-27 to 1994-04-29

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)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 500 mg/l nominal treatment

- Sampling method: Samples of test media were taken at the start and end of the test

- Sample storage conditions before analysis: Refrigerated

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION

- Method: A 500 mg/l nominal concentration of the test substance was prepared by stirring overnight.

- Controls: Dilution water

Test organisms (species):

Daphnia magna

Details on test organisms:

- Type and amount of food: Chlorella vulgaris at 500000 cells/ml

- Feeding frequency: Daily

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

204 mg/l as CaCO3

Test temperature:

20.3 - 21.7ºC

pH:

7.4 - 8.1

Dissolved oxygen:

99 - 100% ASV

Nominal and measured concentrations:

Nominal: 0(Control), 500 mg/l

Measured concentration at start of test: 405 mg/l

Measured concentration at end of test: 436 mg/l

Mean measured concentration: 420 mg/l

Mean measured concentration as a percentage of nominal: 84.1%

The test results are presented and interpreted with reference to nominal concentrations.

Details on test conditions:

TEST SYSTEM

- Test vessel: Conical flasks

- Type: closed

- Material, fill volume: Glass, 150 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: Reconstituted freshwater prepared by mixing (1:1) treated mains water and proprietary mineral water (Ashbourne, Still Natural Water (Nestle, UK. Limited).

- Culture medium different from test medium: no

- Chlorine: <0.1 mg/l (Total)

- Alkalinity: 134 mg/l as CaCO3

- Conductivity: 404 μS/cm

OTHER TEST CONDITIONS

- Adjustment of pH: no

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Immobilization after 24 and 48 h

Reference substance (positive control):

no

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 500 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

but exposure is to hydrolysis product

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

>= 500 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

but exposure is to hydrolysis products

Basis for effect:

mobility

Details on results:

- Mortality of control: 0

Reported statistics and error estimates:

No toxic effects were observed in the test media, the test results were therefore not subject to statistical analysis.

Validity criteria fulfilled:

yes

Conclusions:

A 48-hour EC50 value of >500 mg/l and NOEC of ≥500 mg/l have been determined for the effects of the test substance on mobility of Daphnia magna 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 aquatic invertebrates

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

Remarks:

The result is sourced from secondary literature (company data). The original reference was not available for review and no further information is available.

GLP compliance:

not specified

Analytical monitoring:

not specified

Vehicle:

not specified

Test organisms (species):

Palaemonetes pugio

Test type:

static

Water media type:

saltwater

Limit test:

no

Total exposure duration:

48 h

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

58 mg/L

Nominal / measured:

not specified

Conc. based on:

not specified

Basis for effect:

mortality

Validity criteria fulfilled:

not specified

Conclusions:

A 48 h LC50 value of 58 mg/L has been determined for the effects of the test substance on mortality of Palemonetes pugio. It is likely that the test organisms were exposed to the hydrolysis products of the substance. The study was from a secondary source. As no further details of the test are available, the reliablility of the study could not be determined.

Reference 3

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

secondary literature

Remarks:

The result is reported in a peer reviewed secondary source, however there is insufficient information to fully assess its reliability.

Principles of method if other than guideline:

No guideline specified.

Analytical monitoring:

no

Vehicle:

not specified

Test organisms (species):

Daphnia magna

Test type:

not specified

Water media type:

not specified

Duration:

48 h

Dose descriptor:

EC50

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:

mobility

Conclusions:

An EC50 value of >1000 mg/L has been reported for the test substance to Daphnia magna. The result is reported in a peer reviewed secondary source. It is likely that the test organisms were exposed to the hydrolysis products of the substance.

Reference 4

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

calculation (if not (Q)SAR)

Remarks:

Migrated phrase: estimated by calculation

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)C 50, 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,Daphniaand 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:

48 h

Dose descriptor:

LC50

Effect conc.:

29 600 mg/L

Conclusions:

A 48 h LC50 value of 29600 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

(48-hour) EC50: >500 mg/l mobility Daphnia magna, reliability 1
(48-hour) LC50: 29600 mg/l mortality, hydrolysis product (using an appropriate calculation method), reliability 2

Additional information

A 48-hour EC50 value of >500 mg/l and NOEC of ≥500 mg/l have been determined for the effects of the test substance on mobility of Daphnia magna based on nominal concentration of the substance. The study was conducted according to a standard guideline (EU Method C.2, Acute Toxicity for Daphnia) and GLP and was selected as key study (1994). Two other results are available from secondary literature and therefore of lower reliability; an EC50 value of >1000 mg/l for Daphnia magna and an LC50 value of 58 mg/l for Palaemonetes pugio (marine species) were reported.

As the substance hydrolyses rapidly (half-life approximately 5.5 hours), it is very likely that the test organisms were primarily exposed to the hydrolysis product, methylsilanetriol, retained in the test media. An LC50 of 29600 mg/l was derived for the hydrolysis product using an appropriate calculation method (2011).