3-[3-(1,1,1,3,5,5,5-heptamethyltrisiloxan-3-yl)propoxy]propane-1,2-diol

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:

17 June - 08 July 2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was performed according to OECD Guidelines and in compliance with GLP principles.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2015

Report date:

2015

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

other: Guidance document on aquatic toxicity testing of difficult substances and mixtures, OECD series on testing and assessment number 23, December 14, 2000.

Deviations:

no

Test guideline 4

Qualifier:

according to guideline

Guideline:

other: Food and Agricultural Materials Inspection Centre (FAMIC), 12 Nousan, Notification No 9147, April 2011.

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

3-[3-(1,1,1,3,5,5,5-heptamethyltrisiloxan-3-yl)propoxy]propane-1,2-diol

EC Number:

807-413-2

Cas Number:

70280-68-1

Molecular formula:

C13H34O5Si3

IUPAC Name:

3-[3-(1,1,1,3,5,5,5-heptamethyltrisiloxan-3-yl)propoxy]propane-1,2-diol

Test material form:

other: liquid

Details on test material:

- Name (as cited in study report): X-22-1927
- Appearance: clear light yellow liquid
- Storage conditions: at room temperature

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

15 mL samples were taken from all test concentrations and the control at t=0 h and t=48 h and were analyzed on the day of sampling.

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method:
Individual loading rate ranging from 1.0 to 100 mg/L in the range-finding test and 1.0 to 10 mg/L in the final test were prepared. A two-day period of magnetic stirring was applied and followed by an one-hour settlement period. The aqueous Water Accommodated Fractions (WAFs) were siphoned off and were used as test concentrations. The final test solutions were all clear and colourless.
At 100 mg/L a floating layer was observed and the test solutions were siphoned off a second time, however during the exposure the floating layer returned. This concentration was only applied in the range-finding test and not in the final test.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Strain: Straus, 1820
- Source: In-house laboratory culture with a known history.
- Age at study initiation (mean and range, SD): < 24 hours from parental daphnids of more than two weeks old.
- Method of breeding: at least third generation, obtained by acyclical parthenogenesis under specified breeding conditions
- Feeding during test: none

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test conditions

Hardness:

180 mg/l expressed as CaCO3 and the pH: 7.7 ± 0.3

Test temperature:

21-22 ºC

pH:

8.0-8.1

Dissolved oxygen:

8.5-8.9 mg O2/L

Salinity:

Not applicable

Nominal and measured concentrations:

The actual test concentrations at the start of the test were 0.20, 0.50, 2.3, 4.7 and 8.4 mg/L for the WAFs prepared at 1.0, 1.8, 3.2, 5.6 and 10 mg/L, respectively. The concentrations remained stable but were not in agreement with nominal (20-67%). Based on these results, the geometric average exposure concentrations were calculated to correspond to 0.21, 0.50, 2.1, 4.2 and 6.7 mg/L, respectively (see Table 1 of the results below).

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Material, size, headspace, fill volume: 100 mL, all-glass vessel containing 80 mL of test solution
- Aeration: no
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: adjusted ISO medium
- Culture medium different from test medium: yes, breeding medium is M7 medium

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 hours
- Light intensity: not indicated

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : mobility

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 1.8
- Range finding study
- Test concentrations: Ten daphnids per concentration (in duplicate, 5 per vessel) were exposed to a WAF prepared at a loading rate of 1.0 and 10 mg/L in the combined range-finding test.
- Results used to determine the conditions for the definitive study: No daphnids became immobilized in the control and the WAF prepared at 1.0 mg/L. In the WAF prepared at a loading rate of 100 mg/L all daphnids became immobilized within 24 hours.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

3.4 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% CI 2.9-3.9 mg/L

Details on results:

No daphnids became immobilized at an average exposure concentration of 0.50 mg/L. At an average exposure concentration of 2.1 mg/L and higher, immobility increased with increase of the concentration resulting in 100% immobility at 6.7 mg/L (see table 2 below).

Results with reference substance (positive control):

The 48h-EC50 was estimated to correspond with 0.36 mg/L with 10% effect at 0.32 mg/L and 100% effect at 0.56 mg/l and thus were within the ranges of the expected responses at the different concentrations.

Any other information on results incl. tables

Table 1            Average exposure concentration versus nominal concentration

X-22-1927 WAF prepared at (mg/l)	Measured concentrations (mg/l)		Average exposure (mg/l)
	t=0h	t=48h
1.0	0.220	0.202	0.21
1.8	0.503	0.497	0.50
3.2	2.27	1.99	2.1
5.6	4.73	3.74	4.2
10	8.43	5.36	6.7

 

Table 2            Number of introduced daphnids and incidence of immobilityin the final test

Time (h)	Replicate	X-22-1927 WAF prepared at (mg/l)
		Control	1.0 [0.21]	1.8 [0.50]	3.2 [2.1]	5.6 [4.2]	10 [6.7]
0	A	5	5	5	5	5	5
	B	5	5	5	5	5	5
	C	5	5	5	5	5	5
	D	5	5	5	5	5	5
	Total introduced	20	20	20	20	20	20
24	A	0	0 (2)	0 (1)	0	0	2
	B	0	0 (2)	0	0	1	1
	C	0	0 (1)	0 (1)	0	0	2
	D	0	0	0	0	0	2
	Total immobilised	0	0	0	0	0	7
	Effect %	0	0	0	0	0	35
48	A	0	0	0	0	4	5
	B	0	0 (1)	0	0	3	5
	C	0	0	0	1	4	5
	D	0	0	0	0	3	5
	Total immobilised	0	0	0	1	14	20
	Effect %	0	0	0	5	70	100

( ) number of daphnia observed trapped at the surface of the test solutions. These organisms were reimmersed into the respective solutions before recording of mobility.

[ ] Average exposure concentration (mg/l)

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The 48h EC50 was determined as 3.4 mg/L based on measured geometric mean exposure concentrations.

Executive summary:

Acute toxicity of the test substance to Daphnia magna was determined according to OECD 202 Guidelines and in compliance with GLP principles. The 48h -EC50 was determined as 3.4 mg/L based on measured geometric mean exposure concentrations.