Ethoxytrimethylsilane

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

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 analogue justification provided in IUCLID section 13.

Reason / purpose for cross-reference:

read-across source

Analytical monitoring:

yes

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

271 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

128 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Sublethal observations / clinical signs:

Rainbow trout (Oncorhynchus mykiss) were exposed for 96 hours under static-renewal

conditions to five concentrations of trimethylsilanol ranging in concentration from 65 to 949 mg/L.

The 96-hour LC50 value was 271 mg/L, with 95% confidence intervals of 128 – 481 mg/L. The no

mortality concentration and the NOEC were 128 mg/L.

LC50 values:

Time		LC50 (mg/L)	95% Confidence Interval (mg/L)	Statistical Method
24 Hours		> 949	--1	NA2
48 Hours		523	250 – 949	Binomial Probability
72 Hours		476	402 - 565	Probit
96 Hours		271	128 - 481	Binomial Probability
1 2	Confidence limits could not be calculated with the mortality data obtained. NA = Not applicable. Estimation made by visual inspection of the mortality data.

Conclusions:

A LC50 (96 h) of 271 mg/L (meas. geometric mean) for toxicity to fish was determined in a reliable study with a suitable read-across substance conducted according to an appropriate test protocol, and in compliance with GLP.

Reference 2

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP Guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.1075 (Freshwater and Saltwater Fish Acute Toxicity Test)

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: Samples were collected from the each test chamber of each concentration
- Sampling method: Test solution samples were collected at mid-depth, placed in glass vials, and analyzed immediately.
- Sample storage conditions before analysis: No

Vehicle:

no

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM
- Common name: rainbow trout
- Source: Thomas Fish Company, Anderson, California.
- Age at study initiation: 74 days
- Length at study initiation: 5.9 cm, with a range of 5.5 to 6.3 cm
- Weight at study initiation: 1.7 grams with a range of 1.4 to 2.3 grams

ACCLIMATION
- Acclimation period: 14 days
- Acclimation conditions (same as test or not):
- Type and of food: commercially-prepared diet supplied by Zeigler Brothers, Inc., Gardners, Pennsylvania.
- Feeding frequency: daily. The fish were not fed for at least two days prior to the test or during the test.
- Health during acclimation: During the 14-day period prior to the test no mortalities occurred and the fish showed no signs of disease or stress.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

122 mg/L as CaCO3

Test temperature:

12 ± 1ºC

pH:

8.3 to 8.7

Dissolved oxygen:

≥77% of saturation

Nominal and measured concentrations:

Nominal concentrations of 63, 125, 250, 500 and 1000 mg/L.
the mean measured concentrations for the study were 65, 128, 250, 481 and 949 mg/L, representing 103, 102, 100, 96 and 95% of nominal concentrations, respectively.

Details on test conditions:

TEST SYSTEM
- Material, size, headspace, fill volume: 38 and 54-L stainless steel aquaria containing approximately 30 L of test solution
- Renewal rate of test solution: after 24 hours
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2
- Biomass loading rate: 0.58 g fish/L

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Freshwater obtained from a well approximately 40 meters deep located on the Wildlife International, Ltd. site. The well water is characterized as moderately-hard water.


OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: 16 hours of light and 8 hours of darkness
- Light intensity: 297 lux

EFFECT PARAMETERS MEASURED: All organisms were observed periodically to determine the numbers of mortalities in each treatment and control group. The numbers of individuals exhibiting signs of toxicity or abnormal behavior also were evaluated. Observations were made approximately 4.5, 24, 48, 72 and 96 hours after test initiation.

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

271 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

128 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Sublethal observations / clinical signs:

Rainbow trout (Oncorhynchus mykiss) were exposed for 96 hours under static-renewal

conditions to five concentrations of trimethylsilanol ranging in concentration from 65 to 949 mg/L.

The 96-hour LC50 value was 271 mg/L, with 95% confidence intervals of 128 – 481 mg/L. The no

mortality concentration and the NOEC were 128 mg/L.

LC50 values:

Time		LC50 (mg/L)	95% Confidence Interval (mg/L)	Statistical Method
24 Hours		> 949	--1	NA2
48 Hours		523	250 – 949	Binomial Probability
72 Hours		476	402 - 565	Probit
96 Hours		271	128 - 481	Binomial Probability
1 2	Confidence limits could not be calculated with the mortality data obtained. NA = Not applicable. Estimation made by visual inspection of the mortality data.

Conclusions:

A LC50 (96 h) of 271 mg/L (meas. geometric mean) for toxicity to fish was determined in a reliable study conducted according to an appropriate test protocol, and in compliance with GLP.

Description of key information

LC50 (96 h) = 271 mg/L (measured geometric mean, OECD 203)

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Dose descriptor:

LC50

Effect concentration:

271 mg/L

Additional information

There are no data available on short-term toxicity to fish for ethoxytrimethylsilane (CAS 1825-62-3). 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 hydrolysis product trimethylsilanol (CAS 1066-40-6) has been applied to support the environmental hazard assessment of ethoxytrimethylsilane. 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.

The study with the analogue substance trimethylsilanol (CAS 1066-40-6) was performed according to OECD 203 (GLP). Oncorhynchus mykiss was exposed to the substance up to a test item concentration of 1000 mg/L (nominal) and a control under semi-static conditions. The test concentrations remained stable for the duration of the study. The mean measured concentrations were in the range of 95-103% of nominal. Mortality was recorded above 100 mg/L resulting in a LC50 (96 h) of 271 mg/L.