Diethoxy(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

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 500 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

>= 500 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

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-h 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:

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

Adequacy of study:

key study

Justification for type of information:

Please refer to the attached justification below and the overall justification for grouping of substances attached in IUCLID Section 13.

Reason / purpose for cross-reference:

read-across source

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 500 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Description of key information

EC50 (48 h) > 500 mg/L (nominal, EU Method C.2); based on read across form CAS 2031-67-6

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

500 mg/L

Additional information

There are no reliable data available on the toxicity of diethoxy(methyl)silane (CAS 2031-62-1) to aquatic invertebrates. In accordance with Regulation (EC) No 1907/2006 Annex XI, 1.5 “Grouping of substances and read-across” and in accordance with the read across assessment framework (RAAF, ECHA 2017) a read-across from the analogous substance triethoxy(methyl)silane (CAS 2031-67-6) has been applied to support the environmental hazard assessment of diethoxy(methyl)silane. Details on the read across justification can be found in the attached justification in the respective target entry and in the overall justification for grouping of substances attached in IUCLID Section 13.

A 48 h EC50 value of > 500 mg/L and a NOEC of ≥ 500 mg/L have been determined for the effects of triethoxy(methyl)silane (CAS 2031-67-6) on the mobility of Daphnia magna based on nominal concentration of the substance. The study was conducted according to a standard guideline (EU Method C.2) and GLP (1994). Since the substance hydrolyses rapidly (< 2 min at pH 7 and 25 °C), it is very likely that the test organisms were primarily exposed to the hydrolysis product retained in the test media.

On the basis of the read across data, no short term hazard to aquatic invertebrates is expected from the substance diethoxy(methyl)silane (CAS 2031-62-1).