(3-chloropropyl)dimethoxymethylsilane

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:

2002-04-09 to 2002-07-05

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Guideline study. The study was conducted according to the appropriate OECD test guideline, and in compliance with GLP.

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 10 and 100 mg/L

- Sampling method: An aliquot of freshly prepared test medium was taken from each test concentration before filling the test vessels. A further aliquot was also taken from the combined four replicates of each treatment at the end of the test. Samples of the freshly-prepared test media were only analysed if the samples taken at the end of the test showed concentrations significantly different from expected.

- Sample storage conditions before analysis: Samples were stored at -20ºC prior to analysis.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION

- Method: A 100 mg/L nominal stock solution concentration was prepared by intense stirring for 30 minutes. The stock solution was diluted to produce a further nominal concentration of 10 mg/L.

- Controls: Dilution water

- Evidence of undissolved material (e.g. precipitate, surface film, etc): none reported

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM

- Strain: IRCHA

- Source: LPT Laboratory Culture

- Age at study initiation (mean and range, SD): 6-24 hours

ACCLIMATION

- Acclimation period: at least one week

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

- Type and amount of food: algae (Scenedesmus subspicatus) plus a small quantity of sewage from the aerated phase of treatment.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

250 mg/L as CaCO3

Test temperature:

19-21ºC

pH:

7.7-8.1

Dissolved oxygen:

>/=80% ASV

Salinity:

not applicable

Nominal and measured concentrations:

Nominal concentrations: 0(Control), 10 and 100 mg/L

Measured DOC concentrations were within +/-20% of the theoretical values.

The test results are presented and interpreted with reference to the nominal concentrations.

Details on test conditions:

TEST SYSTEM

- Test vessel:

- Type (delete if not applicable): open

- Material, size: glass, 38 mm diameter, 60 mm tall, 50 mL volume

- 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: aerated reconstituted water

- Alkalinity: 0.8 mmol/L

- Ca/mg ratio: 4:1

- Culture medium different from test medium: no

- Intervals of water quality measurement: Start and end of test


OTHER TEST CONDITIONS

- Adjustment of pH: no

- Photoperiod: 16 h light/8 h dark

- Light intensity: 500 Lux


EFFECT PARAMETERS MEASURED (with observation intervals if applicable): Mobility after 24 and 48 hours


TEST CONCENTRATIONS

- Spacing factor for test concentrations: 10

Reference substance (positive control):

no

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

but exposure is to hydrolysis products

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

but exposure is to hydrolysis products

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 85 mg/L

Nominal / measured:

nominal

Conc. based on:

other: molecular weight corrected value

Remarks:

exposure is to hydrolysis products

Basis for effect:

mobility

Details on results:

- Immobilisation of control: 5%

- Other adverse effects control: none

Reported statistics and error estimates:

The level of immobilisation in the highest treatment was insufficient to determine an EC50 value. The NOEC was determined directly from the raw data.

Table 1. Test results

Nominal test concentration (mg/L)	Mean percentage immobilisation after 24 hours	Mean percentage immobilisation after 48 hours
0 (Control)	5	5
10	0	0
100	15	20

Table 2. Results of analysis of test media

Nominal test concentration (mg/L)	Theoretical DOC concentration (mg/L)	Actual DOC concentration at the end of the test (mg/L)
10	3.9	4.3
100	39.4	38

Validity criteria fulfilled:

yes

Conclusions:

A 48-hour EC50 value of >100 mg/L and NOEC of 10 mg/L have been determined for the effects of the test substance on mobility of Daphnia magna. The results are expressed relative to nominal concentrations of the substance. However it is likely that the test organisms were primarily exposed to the hydrolysis products of the substance.

Description of key information

Short-term toxicity to invertebrates: 48-hour EC₅₀ >100 mg/l (nominal) (highest concentration tested) (OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)). The observations in this study are attributed to the exposure of test organisms to the hydrolysis products in the test system. The result may be expressed in terms of concentration of the hydrolysis product: 48-hour EC₅₀ >85 mg/l as 3-chloropropyl(methyl)silanediol.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

> 85 mg/L

Additional information

 A 48-hour EC₅₀ value of >100 mg/l has been determined for the effects of the registration substance, 3-chloropropyl(dimethoxy)methylsilane (CAS 18171-19-2, EC 242-056-0) on mobility of Daphnia magna based on nominal test concentrations. Due to the rapid hydrolysis rate of the test substance it is very likely that the test organisms were exposed to the hydrolysis products of the substance rather than the parent substance. The results may be expressed in terms of concentration of the hydrolysis product, 3-chloropropyl(methyl)silanediol, by applying a molecular weight correction: (MW of silanol = 154.67 / MW of parent = 182.72) * [CONCENTRATION OF PARENT = >100] = >85 mg/l.