Carbamic acid, N-[(dimethoxymethylsilyl)methyl]-, methyl ester

Short-term toxicity to aquatic invertebrates

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:

27 Aug - 17 Oct 2002

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)

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

GLP compliance:

yes (incl. QA statement)

Remarks:

Hessisches Ministerium für Umwelt, Landwirtschaft und Forsten

Analytical monitoring:

yes

Details on sampling:

- Concentrations: control, 4.6, 10, 21, 46, 100 mg/L (freshly preparred medium)
- Sampling method: Duplicate samples were taken at test start and test end.
- Sample storage conditions before analysis: samples were analysed directly

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: A stock solution of 100 mg/L was prepared by suspending 602 mg test item in 6 L test water by intense stirring for 95 h. Thus, at the start of the test, the main part of the test item were hydrolysis products. Adequate volumes of the stock solution were mixed into test water to obtain the desired test concentrations. In an additional experiment a shorter stirring period of 24 h was chosen to demonstrate that the stirring period has no influence on the outcome of the study.
- Eluate: no
- Differential loading: no
- Controls: yes, test medium control

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Source: supplied 1997 by the Umweltbundesamt, Institut für Wasser-, Boden- und Lufthygiene, Berlin, Germany
- Age at study initiation: 21 h
- Method of breeding: The daphnia were bred under the same conditions as testing conditions. The test organisms were not first brood progeny. The daphnids of the stock culture were fed at least each working day with green algae (Desmodesmus subspicatus) freshly grown in the laboratories.
- Feeding during test: none

ACCLIMATION
- Acclimation period: 21 h
- Acclimation conditions (same as test or not): same as test

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test temperature:

21 °C

pH:

7.8 - 7.9

Dissolved oxygen:

8.1 - 8.4 mg O2/L

Nominal and measured concentrations:

nominal: control, 4.6, 10, 21, 46 and 100 mg/L
measured: At the start of the test before introduction of daphnids in the concentration of 100 mg/L 100% of nominal were found. After 48 h test duration between 89 and 92% of the nominal value were determined.

Details on test conditions:

TEST SYSTEM
- Test vessel: beakers
- Material, size, headspace, fill volume: glass, 250 mL, heaspace: 100 mL, fill volume: 150 mL
- Aeration: no
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: deionised water
- Alkalinity: 0.8 mmol/L
- Ca/mg ratio: 4:1 (based on molarity)
- Conductivity: < 5 µS/cm-1
- Culture medium different from test medium: no

OTHER TEST CONDITIONS
- Photoperiod: 16 h light / 8 h dark
- Light intensity: 500 lux

EFFECT PARAMETERS MEASURED
- Immobility: determined by visual controls after 24 and 48 h

TEST CONCENTRATIONS
- Spacing factor for test concentrations: approx. 2.2
- Range finding study: A range-finding study was performed but not reported in detail.

Reference substance (positive control):

no

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

but the exposure was to hydrolysis products

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

but the exposure was to hydrolysis products

Basis for effect:

mobility

Details on results:

- Mortality of control: 0%

In an additional experiment under identical test conditions, a limit test with a test concentration of 100 mg/L was performed by using a stirring period of 24 h, to demonstrate that the stirring period has no impact on the outcome of the study.

Validity criteria fulfilled:

yes

Conclusions:

A 48 h EC50 of > 100 mg/L has been determined for the effects of the test substance on mobility of Daphnia magna. The results are expressed relative to nominal concentrations of the test substance. However, the substance is subject to rapid hydrolysis and under the test conditions it is therefore likely that exposure will have been to its hydrolysis products.

Description of key information

EC50 (48 h) > 100 mg/L based on immortality of Daphnia magna (EU Method C.2)

Additional information

One experimental study is available investigating the short-term toxicity of methyl-N-{[dimethoxy(methyl)silyl]methyl}carbamate (CAS 23432-65-7) to aquatic invertebrates (Hertl, 2002). This study was performed according to EU Method C.2 (GLP). Daphnia magna was exposed to nominal concentrations of 4.6, 10, 21, 46 and 100 mg/l. Analysis of the dissolved organic carbon (DOC) revealed a mean recovery of 89 - 92%. Since the substance is expected to hydrolyse rapidly in contact with water (DT50: 1.9 h at 20 - 25 °C, pH 7), the result from this study mainly investigated the possible effects of the hydrolysis products (Methyl-N-{[dihydroxy(methyl)silyl]methyl}carbamate und methanol). During stock solution preparation it was ensured by intensive stirring that the parent substance hydrolyses and mainly the hydrolysis products are tested. After an exposure of 48 h no immobilisation was observed resulting in an EC50 of > 100 mg/l.