Dichlorodicyclopentylsilane

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1997 - 1998

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: OECD study under GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1998

Report date:

1998

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Reference

Name:

Unnamed

Type:

Constituent

Details on test material:

- Name of test material (as cited in study report): Silane CP 2
- Physical state: liquid
- Analytical purity: 96.3% (GC)
- Impurities (identity and concentrations): as stated in substance data
- Composition of test material, percentage of components: as stated in substance data
- Lot/batch No.: 10466 QB
- Expiration date of the lot/batch: 1997-12-01
- Stability under test conditions: reaction to hydrolysis product
- Storage condition of test material: in original container, at room temperature, in the dark

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
not applicable

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Sample storage conditions before analysis: room temperatur, in the dark
- For analytical measurements duplicate samples from the freshly prepared stock solution (undiluted filtrate), from the dilution 1:10 and from the control were taken just before the start of the test and at the end of the test period. Additionally, samples were taken from control.

Test solutions

Vehicle:

no

Details on test solutions:

Due to the hydrolytical instability of the test substance in water the hydrolysis product was tested. Therefore , a supersaturated stock suspension of the test substance with a nominal concentration of 100 mg/L was continuously stirred at room temperature in the dark over 6 hours. The stock solution was filtered. The undiluted filtrate with the maximum concentration of dissolved respectively very fine dispersed test substance was used as stock solution for lower concentrated test media.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna (Straus), clone 5
- Source: supplied by University of Sheffield/UK in 1992; since 1992 the clone is bred in the laboratories of RCC
- Age at study initiation (mean and range, SD): 6-24 hours old
- Method of breeding: same water quality as in test (pH, main ions, total hardness)

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

none

Test conditions

Hardness:

2.5 mmol/l as CaCO3

Test temperature:

20 °C

pH:

7.7 to 8.1

Dissolved oxygen:

at least 8.3 mg/l or higher

Nominal and measured concentrations:

100 mg/l (nominal) - 74 mg hydrolysis product/L (mean, measured) = 88 mg test substance/L (mean, caclulated)
Dilution 1: 10 - 7 mg hydrolysis product/L (mean, measured) = 8 mg test substance/L (mean, caclulated)
Dilutions 1:32; 1:100; 1:320; 1:1000; 1:3200; 1:10000 - 2.2; 0.7; 0.22; 0.07; 0.022; 0.007 mg hydrolysis product/L (mean, calculated)
Test concentrations are related to the hydrolysis product. To achieve the amount of Silane CP 2 a correction has to be made by a factor of 1.19.

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: glass beakers of 100 ml filled with 50 ml.
- 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: reconstituted water
- Alkalinity: 0.8 mmol/l
- Ca/mg ratio: 4:1



EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : EC50 at 24 and 48 h

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 7 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Remarks:

hydrolysis product

Basis for effect:

mobility

Effect concentrations 2

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

2.9 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Remarks:

hydrolysis product

Basis for effect:

mobility

Remarks on result:

other: 95% CI: 2.2 - 3.9mg/L

Effect concentrations 3

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

0.7 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Remarks:

hydrolysis product

Basis for effect:

mobility

Details on results:

none

Reported statistics and error estimates:

Moving average interpolation

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Substance is toxic to daphnids.

Executive summary:

The acute toxicity of Silane CP 2 to Daphnia magna was determined in a 48 hour static test in accordance with OECD Guideline 202. Due to the hydrolytical instability of the substance in water the hydrolysis product Dicyclopentylsilanediol was tested. A stock solution with nominal concentration of 100 mg/L was stirred over 6 hours (main part of the substance react to dicyclopentylsilanolediol). The undiluted stock solution and their dilutions were tested. The concentration of the hydrolysis product in the freshly prepared stock solution and after 48 hours have been determined by HPLC with differential refractometer. The concentration of the hydrolysis product was stable during the test period. Based on these data the concentration of Silane CP 2 could be calculated. An EC50 (48 h) of 2.9 mg hydrolysis product/L = 3.45 mg Silane CP 2/L has been determined.