Triethoxypropylsilane

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic algae and cyanobacteria

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:

72 h

Dose descriptor:

EC50

Effect conc.:

> 819 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 819 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

237 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

237 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

607 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Conclusions:

A 72-hour EC50 value of >819 mg/L and NOEC of 237 mg/L have been determined for the effects of the test substance on growth rate and biomass of Scenedesmus subspicatus. The study is considered reliable.

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1993-07-06 to 1993-07-09

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

The Dissolved Organic Carbon (DOC) concentration of the stock solution that was used to prepare the test media was determined and used as the basis for calculating the nominal treatment concentrations.

Vehicle:

no

Details on test solutions:

Six nominal test concentrations of 55, 91, 155, 273, 455 and 819 mg/L. Test media prepared by dilution of a 1000 mg/l stock solution prepared by mixing for 18 h followed by filtration. TOC concentration of stock solution determined to be 408 mg/L, equivalent to a test substance concentration of 910 mg/L..

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM

- Strain: 86.81.SAG

- Source (laboratory, culture collection): Institute for Water, Ground and Air Hygiene, Berlin (Germany)

- Age of inoculum (at test initiation): 3 days

- Method of cultivation: A pre-culture is produced from an original culture by super-inoculation three days before the test begins. From this culture the test cultures are inoculated at a density of about 20000 cells/mL.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Hardness:

Not reported

Test temperature:

24 +/-2ºC

pH:

Start of test: 6.9 - 7.4

End of test: 4.5 - 8.6

Dissolved oxygen:

Not applicable

Salinity:

Not applicable

Nominal and measured concentrations:

Nominal concentrations: 0 (Control), 55, 91, 155, 273, 455 and 819 mg/L

Details on test conditions:

TEST SYSTEM

- Test vessel:

- Type: open Erlenmeyer flasks

- Material: glass

- Aeration: none

- Initial cells density: 20000 cells/ml

- Control end cells density: 900000 cells/ml

- No. of vessels per concentration (replicates): 4 or 5

- No. of vessels per control (replicates): 8


GROWTH MEDIUM

- Standard medium used: yes


TEST MEDIUM / WATER PARAMETERS

- Culture medium different from test medium: no

- Intervals of water quality measurement: start and end of test


OTHER TEST CONDITIONS

- Sterile test conditions: yes

- Adjustment of pH: no

- Photoperiod: continuous

- Light intensity and quality: 8000 Lux


EFFECT PARAMETERS MEASURED (with observation intervals if applicable): Growth rate and biomass

- Determination of cell concentrations: spectrophotometer (absorption at 685 nm)

- Other:


TEST CONCENTRATIONS

- Spacing factor for test concentrations: 1.7

Reference substance (positive control):

no

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 819 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 819 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

237 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

237 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

607 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Reported statistics and error estimates:

The effects on growth were insufficient to determine an EC50 value. The EC10 value was determined by Probit analysis. The NOEC was determined by visual examination of the raw data.

Table 1. Test results

Nominal test concentration (mg/L)	Mean cell density at start of test (cells/mL)	Mean cell density after 24 hours (cells/mL)	Mean cell density after 48 hours (cells/mL)	Mean cell density after 72 hours (cells/mL)
0 (Control)	20000	80000	250000	900000
55	20000	80000	280000	990000
91	20000	80000	280000	940000
155	20000	80000	310000	1010000
273	20000	80000	290000	880000
455	20000	70000	250000	990000
819	20000	70000	230000	500000

Validity criteria fulfilled:

yes

Conclusions:

A 72-hour EC50 value of >819 mg/L and NOEC of 237 mg/L have been determined for the effects of the test substance on growth rate and biomass of Scenedesmus subspicatus. The study is considered reliable.

Description of key information

A 72-hour EC50 value of >819 mg/L (EU Method C.3, 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 triethoxy(propyl)silane. It was considered appropriate to read across from the structurally analogous substance, (3-chloropropyl)triethoxysilane (5089-70-3). A 72-hour EC₅₀value of >819 mg/l and NOEC of 237 mg/l have been determined for the effects of the test substance on the growth rate and biomass of Scenedesmus subspicatus. The study was conducted according to EU Method C.3 (Algal Inhibition test) and is considered reliable for assessment.

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 72 hr EC₅₀of 913 mg/l and NOEC of ≥913 mg/l have been deteremined for the effect on growth rate on the algae Scenedesmus subspicatus (new name: Desmodesmus subspicatus) (EU Method C.3 (Algal Inhibition test) based on nominal concentrations of the substance.