Triethoxypropylsilane

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:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

Please refer to the justification for grouping of substances provided in IUCLID section 13.

Reason / purpose for cross-reference:

read-across source

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

21.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

2.15 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Conclusions:

A 48-h EC50 of 21.2 mg/L and a NOEC of 2.15 mg/L have been determined for the effects of the test substance on mobility of Daphnia magna.

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2002-04-03 to 2002-07-10

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

yes

Remarks:

Test media were not prepared in accordance with OECD guidance for testing difficult substances

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Nominal treatments: 2.15, 4.64, 10.0, 21.5, 46.4 and 100 mg/L

- Sampling method: A sample of test media were taken from all treatments at the start (before introducing the test organisms) and at the end of the test. The sample taken at 48 hours was a combined aliquot from all 4 replicate vessels.

- Sample storage conditions before analysis: Not reported

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION

- Method: The highest test concentration was prepared by vigorously mixing 100 mg/l of the test substance with dilution water for 30 minutes. The other treatments were prepared by dilution of this solution.

- Controls: Dilution water

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM

- Strain: IRCHA

- Source: Laboratory Culture

- Age at study initiation (mean and range, SD): 6-24 hours

ACCLIMATION

- Acclimation period: at least one week

- Acclimation conditions: same as test

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

250 mg/l as CaCO3

Test temperature:

19-21ºC

pH:

7.66-8.54

Dissolved oxygen:

≥80% ASV

Salinity:

Not applicable

Nominal and measured concentrations:

Nominal loading rates: 0(Control), 2.15, 4.64, 10.0, 21.5, 46.4 and 100 mg/L.

Measured dissolved organic carbon concentrations were within 20% of the theoretical values at the end of the test.

The test results are interpreted with reference to nominal test concentrations

Details on test conditions:

TEST SYSTEM

- Test vessel:

- Type (delete if not applicable): open

- Material, size: glass, 38 mm diameter, 60 mm tall, 50 ml volume

- 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: aerated reconstituted fresh water

- Alkalinity: 0.8 mmol/l

- Ca/mg ratio: 4:1

- Culture medium different from test medium: no

- Intervals of water quality measurement: Start and end ot test

OTHER TEST CONDITIONS

- Adjustment of pH: no

- Photoperiod: 16 h light/8 h dark

- Light intensity: 500 Lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): Mobility after 24 and 48 hours

TEST CONCENTRATIONS

- Spacing factor for test concentrations: 2.2

Reference substance (positive control):

no

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

21.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

2.15 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- Immobilization of control: 2.5%

Reported statistics and error estimates:

EC50 values were determined by linear regression employing probit analysis. The NOEC value was determined directly from the raw data.

Table 1. Test results

Nominal test substance loading rate (mg/L)	Mean percentage immobilisation after 24 hours	Mean percentage immobilisation after 48 hours
0 (Control)	0	2.5
2.15	0	0
4.64	0	10
10.0	10	20
21.5	0	15
46.4	15	30
100	90	100

   

Table 2. Results of analysis of test media

Nominal test substance loading rate (mg/L)	Theoretical DOC concentration (mg/l)	Actual DOC concentration at end of test (mg/l)
0 (Control)	-	-
2.15	1.0	0.9
4.63	2.1	0.6
10.0	4.5	5.2
21.5	9.7	8.7
46.3	20.8	16
100	44.9	43

Conclusions:

A 48-h EC50 of 21.2 mg/L and a NOEC of 2.15 mg/L have been determined for the effects of the test substance on mobility of Daphnia magna.

Reference 3

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1993-05-25 to 1993-05-27

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 (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

The concentration of Dissolved Organic Carbon was determined in the stock solution used to prepare the test media. The stock solution concentration (203.5 mg/L DOC, equivalent to a test substance concentration of 454 mg/L) was used as the basis for determining the concentrations in the test media.

Vehicle:

no

Details on test solutions:

- Method: Test media prepared by dilution of a nominal 1000 mg/l stock solution prepared by mixing for 18 h followed by filtration. DOC concentration of stock solution determined and used as the basis for detting the other test concentrations.

- Treatments: Control and nominal test concentrations of 50,73, 100, 145, 204, 291 and 409 mg/L.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM

- Common name: Daphnia magna

- Strain: Clone 5

- Source: Stock culture

- Age at study initiation (mean and range, SD): <24 h

- Method of breeding: Parthenogenetic reproduction

- Feeding during test: None


ACCLIMATION

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

- Type and amount of food: algae and a small quantity of sewage sludge. Sufficient to be consumed each day leaving no residue

- Feeding frequency: daily

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

none

Hardness:

The sum of the Ca2+ and Mg2+ ions was 2.5 mmol

Test temperature:

20 +/-1ºC

pH:

7.3 - 7.5

Dissolved oxygen:

3.8 - 8.1 mg/L (the value of 3.8 mg/L was measured in the highest treatment level at the end of the test. All the daphnia were dead in this treatment)

Salinity:

Not applicable

Nominal and measured concentrations:

Control and nominal test concentrations of 50, 73, 100, 145, 204, 291 and 409 mg/L

Details on test conditions:

TEST SYSTEM

- Test vessel:

- Type: open

- Material, size, headspace, fill volume: glass cylinder containing 10 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: Elendt M4 medium

- Intervals of water quality measurement: end of test


OTHER TEST CONDITIONS

- Photoperiod: Dark


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

TEST CONCENTRATIONS

- Spacing factor for test concentrations: 1.4-1.5


STATISTICS

EC50 and confidence interval determined by Probit analysis

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

177.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 148.9 - 199.1

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

140 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- Mortality of control: 0

Results with reference substance (positive control):

- EC50: >0.9, <1.9 mg/L

Reported statistics and error estimates:

The EC50 values and 95% confidence intervals were calculated by Probit analysis. The NOEC was estimated directly from the raw data.

Table 1. Test results

Nominal test substance concentration (mg/L)	Percentage immobile Daphnia after 24 hours	Percentage immobile Daphnia after 48 hours
0 (Control)	0	0
50	0	0
73	0	0
100	0	0
145	30	55
204	80	90
291	90	100
409	100	100

Validity criteria fulfilled:

yes

Conclusions:

A 48-h EC50 value of 140 mg/L and NOEC of 100 mg/L have been determined for the effects of the test substance on mobility of Daphnia magna.

Description of key information

A 48-h EC50 of 21.2 -140 mg/l, Daphnia magna (OECD 202, read across from CAS 5089-70-3)

Additional information

Note: An acute fish study, a daphnia test and a biodegradation screening study are currently ongoing for the registered substance (i.e. triethoxy(propyl)silane (CAS 2550-02-9)) in order to support the read across from (3-chloropropyl) triethoxysilane (CAS 5089-70-3) . This dossier will be updated once the final study reports are available.

Measured data were not available for triethoxypropylsilane. It was considered appropriate to read across from the structurally analagous substance, (3-chloropropyl) triethoxysilane (5089-70-3).

A 48-hour LC₅₀value of 21.5 mg/l has been determined for the effects of the test substance on mobility of Daphnia magna, based on a guideline study (OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test). The study is considered reliable and was selected as key.

In a second reliable study with (3 -chloropropyl) triethoxysilane (5089-70-3) higher values were obtained: A 48-h EC₅₀value of 140 mg/l and NOEC of 100 mg/l for the effects of the test substance on Daphnia magna. This study was conducted according to EU Method C.2 (Acute Toxicity for Daphnia).

Additional good quality data for the analogue substance, trimethoxypropylsilane, have been read across for triethoxypropylsilane. Both substances share the same silanol hydrolysis product, propylsilanetriol; the other hydrolysis products being ethanol and methanol. A 48-h EC50 value of >816 mg/l and NOEC of ≥816 mg/l (EU Method C.2 (Acute Toxicity for Daphnia) have been determined for the effects of the test substance on mobility of Daphnia magna based on nominal concentrations of the substance.