Registration Dossier

Diss Factsheets

Ecotoxicological information

Short-term toxicity to aquatic invertebrates

Currently viewing:

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1993-06-01 to 1993-06-03
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
EU Method C.2 (Acute Toxicity for Daphnia)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Analytical monitoring:
yes
Details on sampling:
The concentration of hydrolysis products in stock solution determined by Total Organic Carbon analysis. The stock solution concentration (464 mg/l equivalent to a test substance concentration of 1145 mg/L) was used as the basis for determining the concentrations in the test media.
Vehicle:
no
Details on test solutions:
- Method: Test media prepared by dilution of a 1000 mg/L stock solution prepared by mixing for 18 h followed by filtration. TOC concentration of stock solution determined.

- Treatments: Control and nominal test concentrations of 57, 80, 115, 160, 229, 321 and 458 mg/L.
Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM

- Common name: Daphnia magna

- Strain: Clone 5

- Source: Stock culture

- Age at study initiation (mean and range, SD): <24 h

- Method of breeding: Parthenogenetic reproduction

- Feeding during test: None


ACCLIMATION

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

- Type and amount of food: sufficient to be consumed each day leaving no residue

- Feeding frequency: daily
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h
Post exposure observation period:
none
Hardness:
The sum of the Ca2+ and Mg2+ ions was 2.5 mmol
Test temperature:
20 ±1ºC
pH:
7.0 - 7.2
Dissolved oxygen:
6.5 - 8.1 mg/L
Salinity:
Not applicable
Nominal and measured concentrations:
Control and nominal test concentrations of 57, 80, 115, 160, 229, 321 and 458 mg/L.
Details on test conditions:
TEST SYSTEM

- Test vessel:

- Type: open

- Material, size, headspace, fill volume: glass cylinder containing 10 ml of test medium

- Aeration: none

- 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: Elendt M4 medium

- Intervals of water quality measurement: end of test


OTHER TEST CONDITIONS

- Photoperiod: Dark


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Immobilization after 24 and 48 h exposure

TEST CONCENTRATIONS

- Spacing factor for test concentrations: 1.4


STATISTICS

EC50 and confidence interval determined by Probit analysis
Reference substance (positive control):
yes
Remarks:
Potassium dichromate
Duration:
24 h
Dose descriptor:
EC50
Effect conc.:
297.2 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: 223.9 - 224.2
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
168.7 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: 126.9 - 224.2
Details on results:
- Mortality of control: 0
Results with reference substance (positive control):
- EC50: >0.9, <1.9 mg/L
Reported statistics and error estimates:
The EC50 value and its 95% confidence interval was calculated by Probit analysis.

Table 1. Test results

 Nominal test substance concentration (mg/L)  Percentage immobile Daphnia after 24 hours   Percentage immobile Daphnia after 48 hours
 0 (Control)  0  0
 57  5  25
 80  5  25
 115  5  35
 160  0  35
 229  25  45
 321  55  75
 458  90  100
Validity criteria fulfilled:
yes
Conclusions:
A 48-h EC50 value of 168.7 mg/L has been determined for the effects of the test substance on mobility of Daphnia magna. A NOEC was not determined in the test. It is likely that the test organisms were primarily exposed to the hydrolysis products of the substance.

Description of key information

48 hour EC50: 168.7 mg/L for effects of the test substance on mobility of Daphnia magna. It is likely that the test organisms were primarily exposed to the hydrolysis products of the substance. The EC50 is equivalent to 121 mg/L when expressed in terms of the silanol hydrolysis product vinylsilanetriol.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates
Effect concentration:
121 mg/L

Additional information

A 48 hour EC50 value of 168.7 mg/L (nominal concentration) has been determined for the effects of the test substance on mobility of Daphnia magna. It is likely that the test organisms were primarily exposed to the hydrolysis products of the substance. The results may be expressed in terms of the silanol hydrolysis product, by adjusting for the respective molecular weights: MW hydrolysis product/MW parent * E(L)C50 or NOEC value, thus 106.15/148.24 * EC50 of 168.7 mg/L = 121 mg/L as vinylsilanetriol.

The results of this test were selected in preference to those of four other tests because a definitive EC50 value was determined and it was judged to be more reliable.

The following result is from a reliable study included as supporting data:

48-hour EC50 >100 mg/L for effects of the test substance on mobility of Daphnia magna (Dow Corning Corporation, 1979).

Three further studies, for which their reliability could not be ascertained, are also included in the dataset:

48-hour EC50 >100 mg/L for effects of the test substance on mobility of Daphnia magna (Bement, 2001).

EC50 360 mg/L for effects of the test substance on mobility of Daphnia magna (Chandra, 1997).

48-hour EC50 >100 mg/L for effects of the test substance on mobility of Daphnia magna (MOE Japan, 2005).