Trimethoxy(3,3,3-trifluoropropyl)silane

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Experimental start date: 29 April, Experimental completion date: 06 July 2020

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2020

Report date:

2020

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

2004

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Trimethoxy(3,3,3-trifluoropropyl)silane

EC Number:

207-059-3

EC Name:

Trimethoxy(3,3,3-trifluoropropyl)silane

Cas Number:

429-60-7

Molecular formula:

C6H13F3O3Si

IUPAC Name:

trimethoxy(3,3,3-trifluoropropyl)silane

Test material form:

liquid

Specific details on test material used for the study:

Identification: ST2092NM
Batch: 802496
Purity: 100%
Physical state/Appearance: Clear colorless liquid
Expiry Date: 31 October 2020
Storage Conditions: Room temperature in the dark

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Samples were taken from the freshly prepared control and each test group from the bulk test preparation at 0 and 24 hours and from the old test media (pooled replicates) at 24 and 48 hours and stored frozen prior to quantitative analysis. Duplicate samples were taken at 0, 24 and 48 hours and stored frozen for further analysis if necessary. All samples were stabilized by the addition of hexane.

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION:
RANGE-FINDING TEST:
The test concentrations to be used in the definitive test were determined by a preliminary range finding test.
In the range finding test Daphnia magna were exposed to a series of nominal test concentrations of 0.10, 1.0, 10 and 100 mg/L.
A nominal amount of test item (100 mg) was dissolved in test water and the volume adjusted to 1 liter to give the 100 mg/L test concentration from which a series of dilutions was made to give further test concentrations of 0.10, 1.0 and 10 mg/L.
Each prepared concentration was inverted several times to ensure adequate mixing and homogeneity.

INITIAL EXPERIMENTS:
Based on the results of the range finding tests the following test concentrations were assigned: 1.0, 3.2, 10, 32 and 100 mg/L. The results of the first initial experiment showed unexpectedly low measured concentrations of test item, therefore, a second initial experiment was performed.
The results of the second initial experiment showed more than 10% of the control daphnids were immobilized or showed signs of disease or stress, hence the validity criteria was not met.
The results from the initial two experiments were not used for reporting purposes.

DEFINITIVE TEST:
Based on the results of the range finding and initial tests the following test concentrations were assigned to the definitive test: 1.0, 3.2, 10, 32 and 100 mg/L.
A nominal amount of test item (200 mg) was dissolved in test water and the volume adjusted to 2 liters to give the 100 mg/L test concentration from which a series of dilutions was made to give further test concentrations of 1.0, 3.2, 10 and 32 mg/L.
Each stock solution and prepared concentration was inverted several times to ensure adequate mixing and homogeneity.
The concentration and stability of the test item in the test preparations were verified by chemical analysis at 0, 24 and 48 hours

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

The test was carried out using first instar Daphnia magna derived from in house laboratory cultures.
Adult daphnids were maintained in 150 mL glass vessels containing 100 mL Elendt M4 medium in a temperature controlled room maintaining the water temperature at 18 to 22 °C. The lighting cycle was controlled to give a 16 hours light and 8 hours darkness cycle with 20 minute dawn and dusk transition periods. Each culture was fed daily with a mixture of algal suspension (Raphidocelis subcapitata) and GEMMA Micro 300 fish food suspension. Culture conditions ensured that reproduction was by parthenogenesis. Gravid adults were isolated the day before initiation of the test, such that the young daphnids produced overnight were less than 24 hours old. These young were removed from the cultures and used for testing. The diet and diluent water are considered not to contain any contaminant that would affect the integrity or outcome of the study.

Study design

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test conditions

Hardness:

Water harndess: 250 mg/L as CaCO3

Test temperature:

Temperature was maintained at 21°C throughout the test

pH:

7.8 - 8.4.
No treatment related differences for pH.

Dissolved oxygen:

8.2 - 8.8 mg O2/L
No treatment related differences for oxygen concentration.

Nominal and measured concentrations:

Nominal: 1.0, 3.2, 10, 32, 100 mg/L
Measured (geometric mean): 0.06, 0.12, 0.21, 0.36, 0.61 mg/L

Details on test conditions:

TEST SYSTEM
120 mL glass vessels containing approximately 120 mL of test preparation were used. At the start of the test five daphnids were placed in each test and control vessel at random containing the test preparations. Four replicate test and control vessels were prepared. The test vessels were then sealed to reduce evaporation and maintained in a temperature controlled room maintaining the water temperature at 18 to 22 °C with a maximum deviation of ±1 °C and a photoperiod of 16 hours light (between 200 and 1200 Lux) and 8 hours darkness with 20 minute dawn and dusk transition periods. The daphnids were not individually identified, received no food during exposure and the contents of the test vessels were not aerated.
The control group was maintained under identical conditions but not exposed to the test item.
Semi static test conditions were employed in the test in an effort to maintain dissolved test item concentrations. For the test media renewal at 24 hours, the test concentrations were freshly prepared and the daphnids transferred by wide bore pipette from the 24 Hour old test media into the fresh test media.

TEST MEDIUM / WATER PARAMETERS
The water temperature, pH and dissolved oxygen concentrations were recorded daily throughout the test. The measurements at 0 hours and after the test media renewal at 24 hours represent those of the freshly prepared test preparations while the measurements taken prior to the test media renewal, and on termination of the test after 48 hours, represent those of the used or 24 hour old test preparations. The pH and dissolved oxygen concentration were measured using a Hach Flexi handheld meter whilst the temperature was measured using a digital thermometer.
The light intensity during the light period was measured using an ATP Instrumentation Lux meter.
The appearance of the test media was recorded daily.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
Any immobilization or adverse reactions to exposure were recorded at 24 and 48 hours after the start of exposure. The criterion of effect used was that Daphnia were considered to be immobilized if they were unable to swim within 15 seconds after gentle agitation.

VEHICLE CONTROL PERFORMED: yes

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 0.61 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 2

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

0.61 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

RANGE-FINDING TEST:
No immobilization was observed in the control or at test concentrations of 0.10 and 1.0 mg/L, however; 20% immobilization was noted at 10 mg/L at 24 hours, with no immobilization observed at 48 hours and 10% immobilization was observed at 100 mg/L.
Sub lethal effects of exposure were observed in test concentrations of 1.0, 10 and 100 mg/L. These responses were pale appearance, trapping at the surface and reduced mobility.
Based on this information test concentrations of 1.0, 3.2, 10, 32 and 100 mg/L were selected for the definitive test.

Chemical analysis of the test preparations at 0 hours showed measured test concentrations to range from 0.031 mg/L to 25 mg/L. There was a significant decline in the measured concentrations at 48 hours to less than the LOD of the analytical method employed, which was determined to be 0.02 mg/L indicating that the test item not stable under test conditions.

DEFINITIVE TEST:
Verification of Test Concentrations:
Analysis of the fresh test preparations at 0 hours showed measured test concentrations to range from 0.18 to 17 mg/L and from 0.12 to 13 mg/L at 24 hours. Analysis of the corresponding aged test preparations showed measured test concentrations of less than the limit of detection (LOD), determined to be 0.05 mg/L at 24 and 48 hours.
Given this decline in measured test concentrations it was considered justifiable to base the results on the geometric mean measured test concentrations in order to give a "worst case" analysis of the data. The geometric mean measured test concentrations were determined to be 0.061, 0.12, 0.21, 0.36 and 0.61 mg/L.

Immobilization Data:
There was no immobilization in 20 daphnids exposed to a test concentration of 0.61 mg/L for a period of 48 hours. Inspection of the immobilization data gave the following results:
24 hr EC50: >0.61 mg/L
48 hr EC50: >0.61 mg/L

Sub-lethal Effects:
Sub lethal effects of exposure were observed in the test concentration of 0.61 mg/L. These responses were pale appearance and trapping at the surface.

Validation Criteria:
The test was considered to be valid given that none of the control daphnids showed immobilization or other signs of disease or stress and that the oxygen concentration at the end of the test was equal to or greater than 3 mg/L in the control and test vessels.

Water Quality Criteria:
Temperature was maintained at 21 C throughout the test, while there were no treatment related differences for oxygen concentration or pH.
Throughout the test the light intensity was observed to be in the range 889 to 1036 Lux.

Observations on Test Item Solubility:
At the start and throughout the test all control and test solutions were observed to be clear colorless solutions.

Results with reference substance (positive control):

A positive control used potassium dichromate as the reference item at concentrations of 0.32, 0.56, 1.0, 1.8 and 3.2 mg/L.

Analysis of the immobilization data was carried out using the Weibull analysis using linear maximum-likelihood regression at 24 and 48 hours. All statistical analysis was carried out using the ToxRat Professional computer software package. Accordingly the following results were obtained:

24 hr EC50: 0.90 mg/L
24 hr NOEC: 0.56 mg/L
24 hr LOEC: 1.0 mg/L
48 hr EC50: 0.79 mg/L
48 hr NOEC: 0.56 mg/L
48 hr LOEC: 1.0 mg/L

The NOEC is based upon equal to or less than 10% immobilization at this concentration.
The results from the positive control with potassium dichromate were within the normal range for this reference item.

Any other information on results incl. tables

Cumulative Immobilization Data and Observations in the Definitive Test

Geometric Mean Measured Test Concentration (mg/L)	24 Hours
	Cumulative Immobilized Daphnia (Initial Population: 5 Per Replicate)						Observations
	Rep1	Rep2	Rep3	Rep4	Total	%	Rep1	Rep2	Rep3	Rep4
Control	0	0	0	0	0	0	5N	5 N	5 N	5 N
0.061	0	0	0	0	0	0	5 N	5 N	5 N	5 N
0.12	0	0	0	0	0	0	5 N	5 N	5 N	5 N
0.21	0	0	0	0	0	0	5 N	5 N	5 N	5 N
0.36	0	0	0	0	0	0	5 N	5 N	5 N	5 N
0.61	0	0	0	0	0	0	5 N	5 N	5 N	5 N

Geometric Mean Measured Test Concentration (mg/L)	48 Hours
	Cumulative Immobilized Daphnia (Initial Population: 5 Per Replicate)						Observations
	Rep1	Rep2	Rep3	Rep4	Total	%	Rep1	Rep2	Rep3	Rep4
Control	0	0	0	0	0	0	5 N	5 N	5 N	5 N
0.061	0	0	0	0	0	0	5 N	5 N	5 N	5 N
0.12	0	0	0	0	0	0	5 N	5 N	5 N	5 N
0.21	0	0	0	0	0	0	5 N	5 N	5 N	5 N
0.36	0	0	0	0	0	0	5 N	5 N	5 N	5 N
0.61	0	0	0	0	0	0	1 T 4 N	5 N	5 N	1 P 1 T 3 N

Rep  =Replicate

P      = Pale

T      = Trapped at surface

N      = Normal

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The acute toxicity of the test item to the freshwater invertebrate Daphnia magna has been investigated and gave a 48-Hour EC50 value of greater than 0.61 mg/L. The NOEC was 0.61 mg/L.

Executive summary:

Introduction:

A study was performed to assess the acute toxicity of the test item to Daphnia magna. The method followed was designed to be compatible with the OECD Guidelines for Testing of Chemicals (April 2004) No 202, "Daphnia sp., Acute Immobilisation Test" referenced as Method C.2 of Commission Regulation (EC) No. 440/2008.

Methods:

Following a preliminary range‑finding test and initial tests, 20 daphnids (4 replicates of 5 animals) were exposed to aqueous solutions of the test item at nominal concentrations of 1.0, 3.2, 10, 32 and 100 mg/L for 48 hours at a temperature of 21°C under semi‑static test conditions. The number of immobilized Daphnia was recorded after 24 and 48 hours.

Results:

Analysis of the fresh test preparations at 0 hours showed measured test concentrations to range from 0.18 to 17 mg/L and from 0.12 to 13 mg/L at 24 hours. Analysis of the corresponding aged test preparations showed measured test concentrations of less than the limit of detection (LOD), determined to be 0.05 mg/L at 24 and 48 hours.

Given this decline in measured test concentrations it was considered justifiable to base the results on the geometric mean measured test concentrations in order to give a "worst case" analysis of the data. The average geometric mean measured test concentrations were determined to be 0.061, 0.12, 0.21, 0.36 and 0.61 mg/L.

Exposure of Daphnia magna to the test item gave EC₅₀ values of greater than 0.61 mg/L. The No Observed Effect Concentration (NOEC) was 0.61 mg/L.