Reaction mass of [3-(trimethoxysilyl) propyl]urea, [3-(dimethoxyethoxysilyl) propyl]urea, [3-(methoxydiethoxysilyl) propyl]urea and [3-(triethoxysilyl) propyl]urea.

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:

1999-09-21 to 1999-12-15

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: 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

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

Qualifier:

according to guideline

Guideline:

ISO 6341 (Water quality - Determination of the Inhibition of the Mobility of Daphnia magna Straus (Cladocera, Crustacea))

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: Control and 100 mg/l (nominal)
- Sampling method: A 10 ml sample of test medium was taken from the approximate centre of the test vessels at the start and end of the test and analysed on the same day.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: The test media were prepared by direct addition of the substance to the dilution water followed by a short period of stirring with a magnetic stirrer to accelerate dispersion and solution. The resulting test media were clear and colourless.
- Controls: Dilution water

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Strain: Straus, 1820
- Source: Laboratory stock culture
- Age at study initiation (mean and range, SD): <24 hours
- Feeding during test: none

ACCLIMATION
- Type and amount of food: Freshwater algae
- Feeding frequency: Daily

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

250 mg/l as CaCO3

Test temperature:

20.1 - 20.5ºC

pH:

7.7 - 8.0

Dissolved oxygen:

8.7 - 9.1

Nominal and measured concentrations:

Nominal Concentrations: 0(Contol) and 100 mg/l
Analysis of samples taken at the start of the test showed that the concentration based on component M2 was in agreement with nominal (93%). The concentrations of components M3 and M4 were 89 and 78% of nominal. After 48 hours the concentrations of components M2 and M3 had declined by 92 and 99% and component M4 could not be detected.

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Material, size, headspace, fill volume: glass, 100 ml with 80 ml of test medium
- Aeration: none
- Renewal rate of test solution (frequency/flow rate): static
- 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: ISO standard medium prepared with milli-RO water
- Intervals of water quality measurement: Start and end of the test

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 h light, 8 h dark

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

TEST CONCENTRATIONS
- Spacing factor for test concentrations: limit test
- Justification for using less concentrations than requested by guideline: range-finding test
- Range finding study
- Test concentrations: 0(Control) and 100 mg/l
- Results used to determine the conditions for the definitive study: no effects at 100 mg/l

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- Mortality of control: 0

Results with reference substance (positive control):

- Results with reference substance valid? yes
- 48 h EC50: 0.56-1.0 mg/l

Reported statistics and error estimates:

Limit test and therefore no statistical analysis required

The project started with a pilot test with daphnia exposed to 100 mg/l in a static system but without analytical support. Exposure for 48 hours to 100 mg/l induced no effects on the mobility of the daphnids. Thereafter, a limit test was performed with daphnia exposed to 100 mg/l and a blank-control in a static system and samples for analysis of actual exposure concentrations were taken at the start and the end of the limit test.

Quantitative analyses were based on the three major components (NOTOX identification M2, M3 and M4) in A-1160 (methanol stripped). Analysis of the samples taken during the limits test showed that the concentration based on component M2 was in agreement with nominal at the start of the test period (93%). Concentrations based on components M3 and M4 were significantly below nominal at 89% and 78% of nominal, respectively. All three components degraded rather rapidly with degradation of M4>M3>>M2. Within 48 hours of exposure the concentration of M2 had decreased by 92%, the concentration of M3 by 99%, and the concentration of M4 had totally disappeared.

No immobility occurred during the 48-hour test period. Hence, the 48h-EC₅₀daphnia exposed to A-1160 (methanol stripped) was > 100 mg/l in static system. The high rate of hydrolytic degradation of the three components indicated little relevance for testing in a semi-static or flow-through system. Instead, the assessment of the toxic potential of exposure of daphnia to A-1160 (methanol stripped) was considered to be more realistic when exposure to degradation products was included.

The result is considered to be reliable. The test organisms were exposed primarily to the hydrolysis products of the substance.

Validity criteria fulfilled:

yes

Conclusions:

A test mediaum prepared at a nominal concentration of 100 mg/l of ureudopropyltrialkoxysilane, mixed methoxy and ethoxy esters (CAS No. 119612-64-2) was not acutely toxic to Daphnia magna over 48 hours. The result is considered to be reliable. The test organisms were exposed primarily to the hydrolysis products of the substance.

Executive summary:

In an invertebrate acute toxicity study in which Daphnia magna were exposed to A-1160 (methanol stripped), no mortality occured at the limit concentration of 100 mg/L. The result is considered to be reliable. The test organisms were exposed primarily to the hydrolysis products of the substance.

Description of key information

EC50 (48h) > 100 mg/l, mobility Daphnia magna (OECD 202), RL1

Additional information

This study conducted according to OECD 202 and GLP in a static test over 48 hour using Daphnia magna as test organism (NOTOX, 2000f).

A limit test was performed with daphnia exposed to 100 mg/l and a blank-control in a static system and samples for analysis of actual exposure concentrations were taken at the start and the end of the limit test. The substance degraded rapidly within 48 h.

No immobility occurred during the 48-hour test period. Hence, the 48h-EC₅₀ daphnia exposed to Ureidopropyltrialkoxysilane, mixed methoxy and ethoxy esters (116912-64-2) was > 100 mg/l in static system. The high rate of hydrolytic degradation indicated little relevance for testing in a semi-static or flow-through system. Instead, the assessment of the toxic potential of exposure of daphnia to Ureidopropyltrialkoxysilane, mixed methoxy and ethoxy esters (116912-64-2) was considered to be more realistic when exposure to degradation products was included.

The result is considered to be reliable. The test organisms were exposed primarily to the hydrolysis products of the substance.