2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane

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:

from 31 July 2000

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was conducted according to the equivalent OECD guideline. It was conducted according to GLP and analytical monitoring was carried out.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: PARCOM Protocol, Part B

Deviations:

not specified

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: all

- Sampling method: samples were taken from newly prepared WAFs at t = 24 h, then the same (old) exposure media were sampled again after 24 h (at t = 48h), just after replacement.

- Sample storage conditions before analysis: samples of 100 g were taken in 250 ml glass bottles and transferred the same day (cooled) to the analytical laboratories.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION

- Method: The test media were prepared as Water Accomodated Fractions (WAFs). The WAFs were prepared by adding known amounts of the test substance directly into the seawater, with the aid of mechanical stirring for 20 h, followed by 48 h phase separation. The aqueous phases were then tapped directly into the test vessels (the first 200 ml was discarded). The pH of the WAFs was not adjusted to the level of the dilution water. New exposure media were prepared at each replacement day.


- Controls: dilution seawater and stirred seawater

- Evidence of undissolved material (e.g. precipitate, surface film, etc): after stirring, before tapping of the WAF, an oily like layer was observed on the surface of the stirred media. Throughout the test all WAFs were clear and undissolved test material was not observed.

Test organisms (species):

Cyprinodon variegatus

Details on test organisms:

TEST ORGANISM

- Common name: sheepshead minnow

- Source: information withheld

- Age at study initiation (mean and range, SD): juveniles

- Length at study initiation (length definition, mean, range and SD): 1.6 +/- 0.1 cm

- Weight at study initiation (mean and range, SD): 0.057 +/- 0.01 g

- Method of breeding: not reported

- Feeding during test: no


ACCLIMATION

- Acclimation period: > or = 7 days

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

- Type and amount of food: artemia nauplii and dried fish, quantity not report

- Feeding frequency: not reported

- Health during acclimation (any mortality observed): <5%

Test type:

semi-static

Water media type:

saltwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

not reported

Test temperature:

range: 19.8 to 20.4°C

pH:

range: 8.1 to 8.5

Dissolved oxygen:

minimum: 6.5 mg/l

Salinity:

range: 30.0‰ to 30.7‰

Nominal and measured concentrations:

Nominal concentrations: control, stirred control, 100, 180, 320, 560 and 1000 mg/l loading rates of Water Accomodated Fractions (WAFs)
Measured concentrations - initial: <0.01, 4.4, 0.24, 0.56, 0.16, 7.3 mg/l
Measured concentrations - old: <0.01, 0.05, <0.01, 0.01, 0.02, 0.39 mg/l

Details on test conditions:

TEST SYSTEM

- Test vessel: beaker

- Type (delete if not applicable): covered with a watch glass

- Material, size, fill volume: glass, 2 litre, filled with 1.5 L medium

- Aeration: yes, through glass tube

- Renewal rate of test solution (frequency): every 24 h

- No. of organisms per vessel: 10

- No. of vessels per concentration (replicates): 1

- No. of vessels per control (replicates): 1

- No. of vessels per stirred control (replicates): 1


TEST MEDIUM / WATER PARAMETERS

- Source/preparation of dilution water: natural seawater from Eastern Scheldt, USA

- Total organic carbon: 1.24 mg/l

- Culture medium different from test medium: no

- Intervals of water quality measurement: salinity, DO, pH and temperature were measured every 24 h


OTHER TEST CONDITIONS

- Adjustment of pH: none reported

- Photoperiod: not reported

- Light intensity: not reported


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : behaviour and mortality were observed at 3h, 24h, 48h, 72h and 96h.


TEST CONCENTRATIONS

- Spacing factor for test concentrations: 2

- Range finding study: yes

- Test concentrations: not reported

- Results used to determine the conditions for the definitive study: 1 mortality out of 3 fish at 1000 mg/l loading rate

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

LL50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

(WAFs)

Basis for effect:

mortality (fish)

Remarks on result:

other: >LoS

Duration:

96 h

Dose descriptor:

NOELR

Effect conc.:

560 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

(WAFs)

Basis for effect:

mortality (fish)

Remarks on result:

other: >LoS

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 7.3 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: >LoS

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

0.16 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: >LoS

Details on results:

- Behavioural abnormalities: 1 fish at 180 mg/l loading rate showed slow swimming behaviour after 48 h.

- Mortality of control: none

- Other adverse effects control: none

- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: All media were completely clear on visual inspection throughout the test.

- Effect concentrations exceeding solubility of substance in test medium: yes

Reported statistics and error estimates:

None required

Sublethal observations / clinical signs:

Table 1. Measured concentrations with fresh (at 24 h, after renewal) and old media (at 48 h before renewal).

Nominal loading rate (mg/l)	Measured concentrations (mg/l)
	t = 24 h (initial)	t = 48 h (old)
0	<0.01	<0.01
100	4.4	0.05
180	0.24	<0.01
320	0.56	0.01
560	0.16	0.02
1000	7.3	0.39

There appears to be no correlation between exposure concentrations dose and measured concentrations. In the reviewers opinion, this is most likely due to the fact that measured concentrations were all higher than the water solubility (2 ug/l). The measured concentrations decreased further during the 48 h test duration.

Table 2. Summary of mortalities.

Nominal loading rates (mg/l)	Mortalities (%) after 96 h
0	0
0 (stirred)	0
100	0
180	0
320	0
560	0
1000	10

Although 10% mortality is allowed according to the guidelines, the 1 fish which died after 48 h in the 1000 mg/l loading rate was taken into account because the same result was obatined in the range finding test.

Validity criteria fulfilled:

yes

Conclusions:

A 96 h LL50 value of >1000 mg/l loading rate (WAFs), equivalent to >7.3 mg/l measured concentration (initial), has been determined in a reliability 1 study conducted according to GLP and PARCOM, Part B, with the test substance in marine water with the fish Cyprinodon variegatus. A NOELR value of 560 mg/l loading rate (WAFs), equivalent to 0.16 mg/l measured concentration (initial), has also been determined based on a mortality after 48 h at the 1000 mg/l loading rate and an equivalent result being achieved during the range finding test. The LL50 and NOELR are above the water solubility limit of the substance (LoS), therefore the LL50 and NOELR are >LoS.

Reference 2

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1999-09-08 to 1999-09-22

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 204 (Fish, Prolonged Toxicity Test: 14-day Study)

Qualifier:

according to guideline

Guideline:

other: ASTM (2000) Standard practice for conducting acute toxicity tests with fishes, macroinvertebrates and amphibians. Standard E729-96. American Society for Testing and Materials, 100 Barr Harbor Drive, West Conshohocken, PA 19428.

Qualifier:

according to guideline

Guideline:

other: U.S. EPA. (1975) Methods for Acute Toxicity Tests with Fish, Macroinvertebrates and Amphibians. Ecological Research Series (EPA-660/3-75-009).

GLP compliance:

yes

Analytical monitoring:

yes

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION

- Method: A 170 µg a.i./mL stock solution was prepared on days -7, 0 and 7 by placing 0.1678 g (0.1667 g as active ingredient) of D5 in a 1000 mL volumetric flask and diluting to volume with acetone (CAS No. 67-64-1). The solvent control stock solution was comprised of undiluted acetone.

- Controls: dilution water and solvent control

- Chemical name of vehicle (organic solvent, emulsifier or dispersant): acetone

- Concentration of vehicle in test medium (stock solution and final test solution(s) including control(s)): 99 µL/L

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM

- Common name: Rainbow trout

- Source: Test organisms were obtained from Spring Creek Trout Hatchery, Lewistown, Montana. During the 14-day period prior to testing, rainbow trout were held in a 500-L fiberglass tank under a photoperiod of 16 hours light and 8 hours dark. The temperature in the holding tank ranged from 11 to 14 °C during this 14-day period. The water which flowed into the fish holding tank and was characterized as having total hardness and alkalinity ranges as CaCO3 of 32 to 36 mg/L and 24 to 28 mg/L, respectively, a pH of 7.0 to 7.4, and a specific conductivity of 140 to 160 µmhos/cm.

- Length at study initiation (length definition, mean, range and SD): A representative sample (N = 30) of the fish from the test population had a mean total length of 61 mm (range 56 to 68 mm).

- Weight at study initiation (mean and range, SD): A representative sample (N = 30) of the fish from the test population had a mean wet weight of 2.3 g (range 1.7 to 2.9 g)

- Feeding during test; Fish were fed a maintenance ration of 2.0% of the total biomass of the test fish once daily during the exposure period.


ACCLIMATION

- Type and amount of food: The fish were fed a dry commercial pelleted food, ad libitum, daily.

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

14 d

Hardness:

32-36 mg/L as CaCO3

Test temperature:

13 to 15 °C

pH:

pH measured in the dilution water and solvent control vessels ranged from 7.0 to 7.1 at test initiation and 6.6 to 6.8 at test termination.

pH measured in the 17 µg a.i./L treatment level was 6.8 at test initiation and ranged from 6.5 to 6.6 at test termination.

Dissolved oxygen:

The dilution water and solvent control vessels had a measured DO concentration range of 8.9 to 9.3 mg/L at test initiation and 7.4 and 8.7 mg/L respectively, at test termination.

The 17 µg a.i./L treatment level had a measured DO concentration range of 7.5 to 7.7 mg/L at test initiation and 6.2 to 6.8 mg/L at test termination.

Salinity:

Not applicable

Nominal and measured concentrations:

Nominal concentrations in µg/L: 2.2, 3.7, 6.1, 10 and 17

Arithmetic nean measured concentrations in µg/L: 2.1, 3.1, 5.0, 8.6 and 16

Details on test conditions:

TEST SYSTEM

- Test vessel: The toxicity test was conducted in a modified continuous-flow serial diluter system designed to provide five test substance concentrations, a solvent control and a control to duplicate test vessels. The exposure system was designed as a closed system with virtually no opening to atmospheric air, which served to minimize volatilization of the test substance from water. Each 9.6-L glass test vessel was filled to capacity and had a depth of 32 cm. Each vessel was sealed with a Teflon®-lined plastic lid. Solution flowed into and out of the vessel through 4 mm glass tubing fitted into the lid with silicone stoppers. The flow of exposure solution to each vessel was approximately 90 mL per minute.

- No. of organisms per vessel: Ten rainbow trout were impartially selected and distributed to each replicate exposure vessel. Fish were added two at a time to each replicate test vessel until each test vessel contained ten fish. A total of 20 organisms were exposed to each treatment level and control solution.

TEST MEDIUM / WATER PARAMETERS

- Source/preparation of dilution water: Laboratory well water. The dilution water had a total hardness of 32 mg/L to 36 mg/L and alkalinity of 24 to 28 mg/L (as CaCO3), a pH range of 7.0 to 7.4 and a specific conductivity range of 140 to 160 µmhos/cm. The TOC concentration of the dilution water source was 0.67 mg/L for the month of September 1999.

OTHER TEST CONDITIONS

- Lighting (quality, intensity, and periodicity): The test area was illuminated with Sylvania Octron® fluorescent bulbs at an intensity range of 30 to 70 foot candles at the solutions' surface. The test area received a regulated photoperiod of 16 hours of light and 8 hours of darkness. Sudden transitions from light to dark and vice versa were avoided. Light intensity was measured once during the test.

EFFECT PARAMETERS MEASURED: Mortality, total length and wet weight.

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

>= 16 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 16 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

mortality (fish)

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

16 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

other: Mortality, weight, and length

Duration:

14 d

Dose descriptor:

LC50

Effect conc.:

> 16 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

other: Mortality, weight and length

Remarks on result:

other: not calculable

Details on results:

- Number of mortalities as compared to the number exposed: Number of mortalities: 8, Number exposed: 138 (includes controls)

- Mortality of control: Mortality of 10% and 5% was observed among fish in the control and solvent control, respectively. This is considered to be within the expected range of naturally occurring variability for acute tests (ASTM, 2000).

- Cumulative mortality: No mortality was observed among fish exposed to the 2.1, 3.1 and 16 µg a.i./L treatment levels. Mortality of 10% and 15% was observed in the 5.0 and 8.6 µg a.i./L treatment levels, respectively.

- Observations on body length and weight:: Total length of rainbow trout exposed to the control and solvent control averaged 60 and 62 mm, respectively. The wet weight of both the control and solvent control averaged 2.0 g. The total mean length and mean wet weight of fish exposed to the 16 µg a.i./L treatment level were 61 mm and 2.1 g, respectively.

Sublethal observations / clinical signs:

Table 1. Test results

Mean measured concentration (μg/L)	Mean Percentage mortality on Day 1	Mean Percentage mortality on Day 2	Mean Percentage mortality on Day 3	Mean Percentage mortality on Day 4	Mean Percentage mortality on Day 14
0 (Control)	0	0	5	5	10
0 (Solvent control)	0	0	0	0	5
2.1	0	0	0	0	0
3.1	0	0	0	0	0
5.0	0	0	0	0	10
8.6	0	0	0	0	15
16	0	0	0	0	0

Validity criteria fulfilled:

yes

Conclusions:

A 96-h LC50 value of >16 µg a.i./L has been determined for the effects of the test substance on mortality of Oncorhynchus mykiss under flow-through exposure conditions. A NOEC of ≥16 µg a.i./L has been determined in the same test. Continuation of exposure to a total of 14 days resulted in the same values.

Reference 3

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

2007-02-16 to 2007-02-20

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

(Flow-through conditions)

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

On day -1, a quality control (QC) sample was prepared at the same nominal concentration as the stock solution. The QC sample and a sample from the stock solution were analysed for D3 concentration.

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION

- Method: A 16 mg/mL diluter stock solution was prepared prior to the start of the test by placing 3.1932 g of D3 in a 200-mL volumetric flask and bringing to volume with acetone. The resulting stock solution was clear and colourless with no visible undissolved substance. In addition, a 0.500 mL/mL solvent stock solution was prepared by bringing 125 mL of acetone to a final volume of 250 mL with distilled water. The resulting solution was clear and colourless.

Prior to test initiation, a 50 mL Glenco® gas-tight syringe in conjunction with a Harvard syringe pump was calibrated to deliver 0.040 mL/cycle of the 16 mg/mL stock solution into the diluter system's mixing chamber which also received 0.40 L of dilution water per cycle. The concentration of D3 in the mixing chamber was equivalent to the nominal test concentration of 1.6 mg/L.

The solvent control solution was prepared in a similar way to produce a final exposure concentration of 0.10 mL/L.

- Controls: Dilution water control and Solvent control

- Chemical name of vehicle (organic solvent, emulsifier or dispersant): Acetone

- Concentration of vehicle in test medium (stock solution and final test solution(s) including control(s)): 0.1 mL/L

- Evidence of undissolved material (e.g. precipitate, surface film, etc): None

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM

- Common name: Rainbow trout

- Source: Test organisms were obtained from a commercial Hatchery. Prior to testing, the fish were held in a 500-L fiberglass tank under a photoperiod of 16 hours light and 8 hours dark. The temperature in the holding tank was 11°C. The water which flowed into the fish holding tank was characterized as having total hardness and alkalinity ranges as CaCO3 of 44 to 66 mg/L and 20 to 23 mg/L, respectively, a pH of 7.1 to 7.6, and a specific conductivity of 190 to 210 µmhos/cm.

- Length at study initiation (length definition, mean, range and SD): A representative sample (N = 30) of the fish from the test population had a mean total length of 33 mm (range 29 to 39 mm).

- Weight at study initiation (mean and range, SD): A representative sample (N = 30) of the fish from the test population had a mean wet weight of 0.32g (range 0.21 to 0.46 g)

- Feeding during test: None


ACCLIMATION

- Type and amount of food: The fish were fed a dry commercial flaked fish food (Trout Chow), ad libitum, daily. Feeding was stopped 48-hours prior to the start of the test.

Test type:

flow-through

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Hardness:

Total hardness and alkalinity ranges as CaCO3 of 44 to 46 mg/L and 20 to 23 mg/L

Test temperature:

12-15ºC

pH:

6.8 - 7.2

Dissolved oxygen:

6.7-11 mg/L

Salinity:

Not applicable

Nominal and measured concentrations:

Nominal concentrations: 0 (Control), 0 (solvent control)and 1.6 mg/L

Measured concentration in stock solution used to prepare test medium: 15.8 mg/L

The test results are reported and evaluated with reference to nominal concentration.

Details on test conditions:

TEST SYSTEM

The test was conducted using an intermittent-flow proportional diluter  and a a set of eight exposure vessels.  The exposure system was  constructed of glass and silicone sealant, and was designed to provide a  single concentration of test substance, a dilution water control and a  solvent control.  Duplicate vessels were established for each control and  four replicates were estabilished for the treatment level. A 16 mg/mL dilutor stock solution was prepared in acetone and analyzed to  confirm the test substance concentration in this solvent stock.  The solvent stock  solution was delivered into the diluter's mixing chamber via syringe.   The resulting solution was observed to be clear and colorless.  A Glenco®  50-mL gas-tight syringe in conjunction with a Harvard Syringe Pump was  calibrated to deliver 0.040 mL/cycle of 16 mg/mL test substance solution into the  diluter's chemical mixing chamber which received 0.40 L of dilution water  per cycle.  The mixing chamber was continuously mixed.  The concentration  of test substance in the solution contained withing the mixing chamber was equivalent  to the nominal concentration of 1.6 mg/L.  Dilutor flow was maintained at  a rate to deliver approximately 10 solution replacements per day.

The exposure vessels were maintained in an area illuminated with  fluorescent bulbs at an intensity of 63 to 81 footcandles (680 to 870  lux)  with a 16 hour light and eight hour dark photoperiod.  Sudden  transitions between light and dark periods were avoided.  

Dilution water  was characterized as having total hardness and alkalinity ranges (as  CaCO3) of 44 ot 46 mg/L and 22 to 23 mg/L respectively, a pH of 6.9 to  7.4 and a specific conductance of 210 to 220 µmhos/cm.  The total organic  carbon content (TOC) was 0.58 mg/L.  

The dilution water control vessels  had a dissoled oxygen concentration of 11 mg/L at test initiation and a  range of 8.8 to 9.4 mg/L during the test.  

The pH measured in the  dilution water control vessel replicates was 7.2 at test initiation and  ranged from 6.8 to 6.9 at test termination.

Reference substance (positive control):

yes

Remarks:

Acetone

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

>= 1.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC0

Effect conc.:

> 1.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 1.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC100

Effect conc.:

> 1.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

- Mortality of control: 0

Reported statistics and error estimates:

There were no toxic effects observed in the test and therefore statistical analysis of the results was not required.

Sublethal observations / clinical signs:

Table 1. Test results

Treatment	Percentage mortality after 96 hours
0 (Control)	0
0 (Solvent control)	0
1.6 mg/L test substance	0

Validity criteria fulfilled:

yes

Conclusions:

A 96-hour LC50 value of >1.6 mg/L and NOEC of ≥1.6 mg/L have been determined for the effects of the test substance on mortality of Oncorhynchus mykiss. A concentration of 1.6 mg/L corresponds to the approximate water solubility of the substance.

Reference 4

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

Not reported

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Guideline study with acceptable restrictions. No GLP or analysis of exposure media and no description of the test substance. In additon the study is used as read-across.

Principles of method if other than guideline:

Not described

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

no data

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM

- Common name: Rainbow trout

- Source: Fender's Fish Hatchery

- Feeding during test: no data

ACCLIMATION

- Acclimation period: A minimum of two weeks

- Acclimation conditions: same as test

- Type and amount of food: not reported

Test type:

not specified

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

Soft water

Test temperature:

12ºC

pH:

no data

Dissolved oxygen:

no data

Salinity:

Not applicable

Nominal and measured concentrations:

Nominal concentrations: 0(Control), 100, 320 and 1000 mg/l

Details on test conditions:

TEST SYSTEM

- Test vessel:

- Type: open

- Material: Polyethylene lined

- Aeration: no data

- Renewal rate of test solution (frequency/flow rate): no data

- No. of organisms per vessel: 10

- No. of vessels per concentration (replicates): 1

- No. of vessels per control (replicates): 1


TEST MEDIUM / WATER PARAMETERS

- Source/preparation of dilution water: Reconstituted soft water (EPA 660/3-75-009)

- Culture medium different from test medium: no

- Intervals of water quality measurement: no data


OTHER TEST CONDITIONS

- Adjustment of pH: no data

- Photoperiod: no data

- Light intensity: no data


EFFECT PARAMETERS MEASURED (with observation intervals if applicable): daily mortality


TEST CONCENTRATIONS

- Spacing factor for test concentrations: 3.2

- Range finding study: no data

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

191 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 125-281

Details on results:

- Mortality of control: 10% (1 fish)

- Other adverse effects control: none

Reported statistics and error estimates:

The LC50 value was calculated by probit analysis based on Finney's Method (Statistical Methods in Biological Assay, 1952).

Sublethal observations / clinical signs:

Table 1. Test results

Nominal test concentration (mg/l)	Percentage mortality after 24 hours	Percentage mortality after 48 hours	Percentage mortality after 72 hours	Percentage mortality after 96 hours
0 (Control)	0	0	10	10
100	0	0	0	0
320	30	100	100	100
1000	90	100	100	100

Validity criteria fulfilled:

yes

Conclusions:

A 96-hour L50 value of 191 mg/l and NOEC of 100 mg/l have been determined for the effects of the test substance on mortality of Oncorhynchus mykiss. It is likely that the test organism were primarily exposed to the hydrolysis product of the test substance.

Description of key information

Short-term toxicity to fish: 96 hour LL₅₀: >1000 mg/l loading rate (WAFs) (highest concentration tested) (OECD Guideline 203 (Fish, Acute Toxicity Test)), equivalent to >7.3 mg/l measured initial concentration, mortality Cyprinodon variegatus. The values are above limit of solubility of the substance in water.

Additional information

A 96 hour LL₅₀ value of >1000 mg/l loading rate (WAFs), equivalent to >7.3 mg/l measured concentration (initial) (highest concentration tested), has been determined in a reliability 1 study conducted with the registration substance using the salt water fish Cyprinodon variegatus. The study was conducted in accordance with OECD TG 203 and in compliance with GLP (TNO, 2002). A NOELR value of 560 mg/l loading rate (WAFs), equivalent to 0.16 mg/l measured concentration (initial), has also been determined based on one mortality after 48 hour at the 1000 mg/l loading rate and an equivalent result being achieved during the range finding test. The LL₅₀ and NOELR are above the water solubility limit of the substance (LoS: 0.0073 – 0.0088 mg/l at 23°C), therefore the LL₅₀ and NOELR are >LoS. For monoconstituent substances it would not normally be appropriate to test at concentrations above the solubility limit. However, the results as reported do provide strong evidence of the absence of toxicity at the solubility limit of the substance following short-term exposures.

The data above are supported by read-across evidence relevant to the impurities. The registration substance has an average purity of >70% Vi4-D4, with <20% 2,4,6,8,10-pentamethyl-2,4,6,8,10-pentavinylcyclopentasiloxane Vi5-D5 (CAS 17704-22-2; Impurity 1) and <10% 2,4,6-trimethyl-2,4,6-trivinylcyclotrisiloxane Vi3-D3 (CAS 3901-77-7; Impurity 2) present as impurities. After due consideration of the properties, the presence of these impurities is not expected to affect the overall hazard profile of the substance. Read-across studies are in place as supporting studies, to consider the properties of the impurities.

Data for Vi5-D5 are read-across from decamethylcyclopentasiloxane D5 (CAS 541-02-6), data for Vi3-D3 are read-across from hexamethyltrisiloxane D3 (CAS 541-05-9). These siloxanes belong to the structural class of siloxanes (alkyl, vinyl, aryl or hydrogen substituted) and are expected to have similar properties with regard to aquatic ecotoxicity.

A reliable short-term fish study is available for the siloxane D5 (CAS 541-02-6) and is read-across to Impurity 1 (Springborn Laboratories, 2000). This study (14 day flow through test with Oncorhynchus mykiss) gave a result 96 hour LC₅₀ >16 µg/l and 14 day LC₅₀ >16 µg/l. LC₅₀ was not reached within the limit of solubility in test media.

A reliable short-term fish study is available for the siloxane D3 (CAS 541-05-9) and is read-across to Impurity 2 (Springborn Smithers, 2007). This study (96 hour flow through test with Oncorhynchus mykiss) gave a result 96 hour LC₅₀ >1.6 mg/l. LC₅₀ was not reached within the limit of solubility in test media.

A 96 hour LC₅₀ value of 191 mg/l (nominal concentration) has been determined for the effects of trimethoxy(vinyl)silane (CAS 2768-02-7) on mortality of Oncorhynchus mykiss (Dow Corning, 1979). The data indicate that the vinyl side chain is unlikely to contribute significant excess ecotoxicity to the substance.

 

Further information is given in a supporting report (PFA, 2017) attached in Section 13 of the IUCLID dossier.