Diethoxy(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:

no

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)
- 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)

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2.0

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 500 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

>= 500 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

- Behavioural abnormalities: At the end of the test fish 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-h 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:

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:

96 h

Dose descriptor:

LC50

Effect conc.:

> 500 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Description of key information

LC50 (96 h) > 500 mg/L (nominal, EU Method C.1); based on read across from CAS 2031-67-6

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

500 mg/L

Additional information

No studies on the short-term toxicity to fish are available for diethoxy(methyl)silane (CAS 2031-62-1). 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 96 h LC50 value of > 500 mg/L has been determined for the effects of triethoxy(methyl)silane (CAS 2031-67-6) on the mortality of Danio rerio based on nominal concentration of the substance. The study was conducted according to a standard guideline (EU Method C.1) and to GLP (1994). Since the substance hydrolyses rapidly (< 2 min at pH 7 and 25 °C), it is very likely that the test organisms were predominantly exposed to the hydrolysis product retained in the test media.

On the basis of the read across data, no short-term effects on fish are expected from the target substance diethoxy(methyl)silane (CAS 2031-62-1).