Trisiloxane, 3-ethyl-1,1,1,3,5,5,5-heptamethyl-

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2005-11-30 - 2006-01-09

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Version / remarks:

1992

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Version / remarks:

1992

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 100 mg/L and control
- Sample storage conditions before analysis: stored in refrigerator (4 +/- 4°C)

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: 1500 mg of the test item were dissolved in 15000 mL test water by intense stirring for 5 days in a closed system (to prevent evaporation of the test item from the test media) to obtain a saturated solution of the poorly water soluble test item in the test media.

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM
- Common name: Rainbow trout
- Length at study initiation (length definition, mean, range and SD): 5.22 +/- 0.19 cm
- Weight at study initiation (mean and range, SD): 1.29 +/- 0.20 g

ACCLIMATION
- Acclimation period: for at least 12 days before the start of the test the fish were acclimated to the test temperature.
- Type and amount of food during acclimation: commercial fish diet
- Health during acclimation (any mortality observed): During the last 12 days prior to the start of the test no fish died in the fish batch and all fish were healthy.

FEEDING DURING TEST
- Frequency: no feeding

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Hardness:

250 mg/L as CaCO3

Test temperature:

15 - 16°C

pH:

7.7 - 8.0

Dissolved oxygen:

>= 8.3 mg/L

Nominal and measured concentrations:

- 100 mg/L (nominal)
- freshly prepared test media (0 h) collected at test start were analysed
- test item concentrations were below the limit of quantification (0.2 mg test item/L), no further samples were analysed

Details on test conditions:

TEST SYSTEM
- Test vessel: 18 L glass aquaria with 15 L test medium
- Aeration: slightly aerated
- Renewal rate of test solution (frequency/flow rate): renewal every 24h
- No. of organisms per vessel: 7
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1

OTHER TEST CONDITIONS
- Photoperiod: 16h light: 8h dark
- Light intensity: 460 - 620 lux

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

No mortality and no symptoms of intoxication could be observed in the control and the test concentration (nominal 100 mg/L).

Sublethal observations / clinical signs:

Table 1: Mortality and Symptomes of Intoxication

Nominal concentration [mg/L]	Exposure time [h] (dead fish/ fish with symptoms)
	2	24	48	72	96
control	0/0	0/0	0/0	0/0	0/0
100	0/0	0/0	0/0	0/0	0/0

 

Table 2: pH- values in the Test media

pH
Nominal concentration [mg/L]	Exposure time [h]
	2	24		48		72		96
	new	old	new	old	new	old	new	old
control	8.0	7.8	7.9	7.8	7.9	7.8	7.8	7.9
100	7.9	7.8	7.9	7.8	7.9	7.7	7.9	7.9

 

Table 3: Dissolved Oxygene Concentrations in the Test Media

Dissolved Oxygen [mg/L]
Nominal concentration [mg/L]	Exposure time [h]
	2	24		48		72		96
	new	old	new	old	new	old	new	old
control	8.5	9.9	10.2	10.4	10.5	10.0	10.8	9.6
100	8.3	9.8	10.2	10.8	9.7	10.4	10.3	9.6

 

Table 4: Temperatures in the Test Media

Temperature [°C]
Nominal concentration [mg/L]	Exposure time [h]
	2	24		48		72		96
	new	old	new	old	new	old	new	old
control	15	16	16	16	16	15	15	15
100	16	16	16	16	16	15	15	15

Validity criteria fulfilled:

yes

Conclusions:

The 96 h LC50 to Oncorhynchus mykiss was found to be above 100 mg/L (loading rate).

Description of key information

The toxicity of 3-ethylheptamethyltrisiloxane on fish (Oncorhynchus mykiss) was determined in a GLP study according to OECD 203. No adverse effects were observed and the 96 h LC₅₀ to Oncorhynchus mykiss was found to be above 100 mg/L (loading rate).