4,4,7,7-tetraethoxy-3,8-dioxa-4,7-disiladecane

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:

1998-08-10 to 1998-08-14

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

Guideline study. The study was conducted according to the appropriate OECD test guideline, and in compliance with GLP. However under there were issues with the analytical work and the methodology used in the study means that factors other than intrinsic toxicity of the test substance could have contributed to the effects observed

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 6.25, 12.5, 25, 50 and 100 mg/L

- Sampling method: Samples of freshly-prepared test media were taken from all treatments at the start of the test and in all treatments except 25, 50 and 100 mg/L (where all fish were dead) at the 72-h test medium renewal. Samples of old test media that contained surviving fish were taken after 24 hours and again at the end of the test.

- Sample storage conditions before analysis: Samples were stored refrigerated prior to analysis.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION

- Method: The test substance was added directly to the test vessels and the contents of the vessels stirred for 10 minutes prior to introducing the test organisms.

- Controls: Dilution water

- Evidence of undissolved material (e.g. precipitate, surface film, etc): The test substance was not fully soluble.

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

TEST ORGANISM

- Common name: Zebrafish

- Source: City Zoo, Darmstadt, Germany.

- Length at study initiation (length definition, mean, range and SD): 3.4 +/-0.1 cm

- Weight at study initiation (mean and range, SD): 0.31 +/-0.06 g

- Feeding during test: none

ACCLIMATION

- Acclimation period: 2 weeks

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

- Type and amount of food: Tetra Min, TETRA-Werke, Melle, Germany

- Health during acclimation (any mortality observed): <2% in 5 weeks prior to test

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

250 mg/L as CaCO3

Test temperature:

21-22ºC

pH:

7.4-8.1

Dissolved oxygen:

≥6.6 mg/L

Salinity:

not applicable

Nominal and measured concentrations:

Nominal loading rates: 0(Control), 6.25, 12.5, 25, 50 and 100 mg/L.

Measured concentrations in the test media prepared at nominal loading rates of 6.25 mg/l and higher ranged between 62 and 110% of nominal. The concentrations in the Control and 6.25 mg/L treatment were below the limit of quantification.

The results have been reported and interpreted with reference to nominal concentrations.

Details on test conditions:

TEST SYSTEM

- Test vessel: aquaria

- Type (delete if not applicable): open

- Material, size, headspace, fill volume: glass, 5 L containing 3 L of test medium.

- Aeration: yes

- Renewal rate of test solution (frequency/flow rate): daily

- No. of organisms per vessel: 7

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

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

- Biomass loading rate: 0.72 g/L

TEST MEDIUM / WATER PARAMETERS

- Source/preparation of dilution water: Reconstituted freshwater prepared by adding analytical grade salts to deionised water.

- Alkalinity: 0.8 mmol/L

- Ca/mg ratio: 4:1

- Culture medium different from test medium: no

- Intervals of water quality measurement: daily

OTHER TEST CONDITIONS

- Adjustment of pH: no

- Photoperiod: 16 h light, 8 h dark

- Light intensity: 216-384 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): mortality after 2, 24, 48 72 and 96 h.

TEST CONCENTRATIONS

- Spacing factor for test concentrations: 2

- Range finding study: yes

- Test concentrations: no data

- Results used to determine the conditions for the definitive study: no data

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

LL50

Effect conc.:

16 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 12.2-21.1

Duration:

96 h

Dose descriptor:

LL0

Effect conc.:

< 6.25 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LL100

Effect conc.:

25 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

NOELR

Effect conc.:

< 6.25 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LOELR

Effect conc.:

6.25 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

- Mortality of control: 0

- Effect concentrations exceeding solubility of substance in test medium: The test substance was not fully soluble at all the tested loading rates.

Reported statistics and error estimates:

LL50 values and their 95% confidence intervals were calculated, where possible, by moving-average interpolation. The NOELR,LOELR, LL10 and LL100 values were determined directly from the raw data.

Sublethal observations / clinical signs:

Table 1. Test results

Nominal test substance 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	0	0
6.25	0	0	0	14
12.5	0	0	0	57
25.0	0	57	100	100
50.0	0	100	100	100
100	100	100	100	100

Table 2. Results of analysis of test media

Nominal test substance concentration (mg/L)	Mean percentage of nominal on Day 0 (fresh)	Mean percentage of nominal on Day 1 (fresh/old)	Mean percentage of nominal on Day 2 (fresh/old)	Mean percentage of nominal on Day 3 (fresh/old)	Mean percentage of nominal on Day 4 (old)
0 (Control)	<LOQ	-/<LOQ	-/-	<LOD/-	<LOD
6.25	<LOQ	-/<LOQ	-/-	<LOD/-	<LOQ
12.5	<LOQ	-/71	-/-	<LOQ/-	72
25.0	105	-/98	-/-	-/64	-/-
50.0	88	-/82	-/-	-/73	-/-
100.0	110	-/96	-/-	-/-	-/-

Validity criteria fulfilled:

yes

Conclusions:

A 96 hour LL50 value of 16 mg/L and NOEL of <6.25 mg/L have been determined for the effects of the test substance on mortality of Brachydanio rerio. The results are expressed in terms of nominal loading rates of the substance.

Description of key information

Short-term toxicity to fish: 96 hr LC50 16 mg/L and NOEC <6.25 mg/L (nominal) (OECD 203) in terms of test concentration of the parent substance. The observations in this study are attributed to the exposure of test organisms to the parent substance in the test system.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

16 mg/L

Additional information

A 96-h LC50 value of 16 mg/L and NOEC of <6.25 mg/L (nominal) have been determined for the effects of the registered substance on mortality of Brachydanio rerio (new name: Danio rerio). In view of the test media preparation method and semi-static exposure regime, it is likely that the test organisms were exposed predominantly to the parent substance.

The study was supported by ICP analysis of the parent substance and concentrations ranged between 62 and 110% of nominal, consistent with the expectation of some degradation due to hydrolysis in the test media.

Above a concentration of approximately 1000 mg/L, oligomeric, cyclic or cross-linked condensation products could potentially form over time in the aqueous test media. Evidence of undissolved material (parent substance or precipitated products) is indicated in the study report for this test and therefore physical effects may have contributed to some extent to the mortality effects in the test. The use of the E(L)C50 value as a measurement of intrinsic toxicity represents a conservative interpretation of the test findings.