2-Propenoic acid, 2-methyl-, tris(1-methylethyl)silyl ester

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:

25 May to 27 May 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Recent study conducted by a GLP certified laboratory in accordance with a suitable study guideline.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

yes

Remarks:

Not possible to verify the concentration was at least 80% of the nominal during the test as the saturated solution was below the level of analytical detection. This does not affect the validity of the study as there was no toxicity at a saturated solution

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Tripropan-2-ylsilyl 2-methylprop-2-enoate

EC Number:

700-182-8

Cas Number:

134652-60-1

Molecular formula:

C13 H26 O2 Si

IUPAC Name:

Tripropan-2-ylsilyl 2-methylprop-2-enoate

Details on test material:

- Name of test material: TIS-M
- Lot/batch No.: 9925
- Expiration date of the lot/batch: 2 December 2010
- Storage condition of test material: Under nitrogen at room temperature (15-25°C), continuously protected from all light.

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

-Three samples were taken from both test solutions. One sample was taken from both control solutions.

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)

Dilution and Preparation of Testing Solutions: Because the test item is very poorly soluble in water and in addition hydrolytically unstable, the test item solution used in the test was prepared by a method which ensured to carry out the test at the limit of solubility of the test item during the whole test period. The method is based on the elution of the test substance with the test medium from a column, which is charged with an inert support material coated with an excess of the test substance. For this method glass beads serve as support material and ISO medium is used as eluent. The glass beads with a high surface area to volume ratio allows a relatively large amount of test substance to be coated on the surface and provides a large area over which dissolving of the test substance can take place.

An amount of 200 mg test substance was dissolved in 100 ml of acetone [supplier: REANAL; Lot no.: KBM60548; Exp. Date: January 2012 (the test substance information supplied by the Sponsor showed that acetone is a suitable solvent)]. This solution was added to about 50 g support material. The solvent was completely evaporated using a rotary evaporator. The dry support material was poured into the column, filled with ISO medium. The column was connected to a re-circulating pump. The flow through the column was started approximately 1 hour before the introduction of the daphnids (to achieve the constant saturated solution) and run over the test period. The flow rate of the water pumped through the column filled with test item allowed a theoretical recirculation of the whole tank volume approximately every 6 minutes, so 1 hour represents a recirculation of approximately 10 times.

Untreated Control: The dilution water (ISO-medium) was used without of addition of the test item

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia
- Strain: Daphnia magna
- Source: National Institute of Public Health,
1097 Budapest Gyáli u. 2-6. Hungary
- Age at study initiation: Less than 24 h old.
- Weight at study initiation (mean and range, SD):
- Length at study initiation (length definition, mean, range and SD):
- Valve height at study initiation, for shell deposition study (mean and range, SD):
- Peripheral shell growth removed prior to test initiation:
- Method of breeding:
- Feeding during test: The animals were not fed during the test. Before the test the Daphnia culture was fed with concentrated algal suspension of Pseudokirchneriella subcapitata.

ACCLIMATION
- Acclimation period: There was no acclimatization because the water used was similar to the culture water

Study design

Test type:

flow-through

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Post exposure observation period:

0 hrs - all observations done during the exposure period.

Test conditions

Hardness:

The hardness of the test medium (CaCO3): 169 mg/L

Test temperature:

Temperature (in the climate chamber): 20.6 – 21.3 °C
Temperature (in the test vessels): 20.9 – 21.1 °C
The water temperature was measured daily in the each test vessel.

pH:

The pH of the test solution was not adjusted and it was within the range 6 - 9, and not vary by more than 1.5 units in any one test.

Dissolved oxygen:

The dissolved oxygen concentration was greater than 3 mg/L during the test. The dissolved oxygen concentration was measured in each test vessel at the start and at the end of the test.

Salinity:

No data.

Nominal and measured concentrations:

100% v/v saturated solution

Details on test conditions:

TEST SYSTEM
- Test vessel: glass beaker.
- Type: open
- Material, size, headspace, fill volume:
- Aeration: yes but not specified.
- Type of flow-through: no data.
- Renewal rate of test solution : theoretical recirculation of the whole tank volume approximately every 6 minutes
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2

OTHER TEST CONDITIONS
- Adjustment of pH: no data.
- Photoperiod: 16 hours light and 8 hours darkness (Artificial illumination).
- Light intensity: no data.

EFFECT PARAMETERS MEASURED:
- The immobility or mortality of the Daphnia was determined by visual observation 24 and 48 hours after the start of the test. Those animals not able to swim within 15 seconds after gentle agitation of the test beaker are considered to be immobile.
- The water temperature, oxygen concentrations and pH of the controls and the test solution were measured at the beginning and at the end of the test.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: Only one concentration used: 100% v/v saturated solution.
- Range finding study: yes - preliminary test.
- Test concentrations: 0.01,0.1, 1, 10, 100 % v/v saturated solution for preliminary range finding study. 100% v/v saturated solution only for main study.
- Results used to determine the conditions for the definitive study: yes

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 100 other: % v/v solution

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 2

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 other: % v/v solution

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 3

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

> 100 other: % v/v solution

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 4

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

100 other: % v/v solution

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- Behavioural abnormalities: None detected.
- Observations on body length and weight:
- Mortality of control: None observed.
- Abnormal responses: None detected.

.

Results with reference substance (positive control):

- Results with reference substance valid - yes Potassium dichromate is tested at least twice a year to demonstrate satisfactory test conditions.
- Mortality: no data.
- EC50: after 24h: 1.84 mg/L, (95 % confidence limits: 1.70 – 1.99 mg/L)

Reported statistics and error estimates:

No statistical analysis was performed because of the lack of toxic effects. The EC50, NOEC and LOEC were determined directly from the raw data.

Any other information on results incl. tables

VALIDITY

There were no immobilized animal in the control group and the dissolved oxygen concentration at the end of the test in control and test vessels was more than 3 mg/L. All validity criteria were within acceptable limits and therefore the study can be considered as valid.

Comments:

There was no immobilisation in 20 daphnids exposed to each groups. In addition to immobility, no abnormal behaviour or appearance of test animals was detected

Table 1: Table 1.: Results of the Preliminary Range-Finding Test

Nominal concentrations (% v/v saturated solution)	Untreated control	0.01	0.1	1	10	100
Number of treated/immobilised animals	10 / 0	10 / 0	10 / 0	10 / 0	10 / 0	10 / 10

Table 2: Number and percentage of immobilised animals

Test group	Number of treated animals	Number of immobilised animals
		24 hours		48 hours
		Number	Percent	Number	Percent
Control	20	0	0	0	0
100% v/v saturated solution	20	0	0	0	0

Table 3: Temperature measured in the test vessels (°C)

Parameter	Test Group	Measurement (hours)
		0	24	48
°C	Control	20.9	21.0	21.0
		20.9	21.0	21.0
	100% v/v Saturated solution	21.0	21.0	21.0
		21.0	21.0	21.1

Table 4: Oxygen concentration measured in the test vessels (mg/L):

Parameter	Test Group	Measurement (hours)
		0	48
mg/L	Control	6.9	6.8
		6.9	6.9
	100% v/v Saturated solution	6.9	6.9
		6.9	6.8

Table 5: pH measured in the test vessels:

Parameter	Test Group	Measurement (hours)
		0	48
pH	Control	7.80	7.70
		7.82	7.72
	100% v/v Saturated solution	7.78	7.80
		7.79	7.78

Table 6: Immobilisation of the test animals:

Test Group	Number of animals	Number of immobilised animals
		24h	48h
Control	10	0	0
	10	0	0
100% v/v Saturated solution	10	0	0
	10	0	0

Table 7: Data of the regression lines at the start and at the end of the study (Calibration - analysis):

Date of measurement	Analytical occasion	Constant	X Coefficient	R. Squared
25 May 2010	Start of the study	-1332	35806	0.998
27 May 2010	End of the study	-5363	37337	0.999

Table 8: Measured concentrations from HPLC analysis:

Sample code	Measured concentrations
	At the start	At the end
	mg/L	mg/L
Control	Not detected.	Not detected.
Control with acetone	Not detected.	Not detected.
Test Solution 1	<0.2	<0.2
	<0.2	<0.2
	<0.2	<0.2
Test solution 2	<0.2	<0.2
	<0.2	<0.2
	<0.2	<0.2

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The 24h and 48h EC50 value for the registered substance was determined to be > 100% v/v saturated solution. The No-Observed Effect Concentration was determined to be 100% v/v saturated solution and the Lowest Observed Effect Concentration was determined to be > 100% v/v saturated solution.Based on the results of this study, the registered substance TIS-M was determined to have toxic effect at saturation; the EC50 results and the LOEC are higher than the solubility level of the test item in the test medium.

Executive summary:

The short-term toxicity of the registered substance to Daphnia (Daphnia magna) was assessed according to the EU Method C.2 (Acute Toxicity for Daphnia). An untreated Control of dilution water was also used. The 24 and 48hr EC₅₀values were all > 100% v/v saturated solution and LOEC value was > 100% v/v saturated solution, so it was determined that the test item TIS-M had no toxic effect at saturation.