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Short-term toxicity to fish

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Endpoint:
short-term toxicity to fish
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
1996-11-11 to 1996-11-15
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
The study was conducted according to an appropriate OECD test guideline, and in compliance with GLP, and was considered to be reliability 1 (reliable without restrictions).
Qualifier:
according to
Guideline:
EU Method C.1 (Acute Toxicity for Fish)
Deviations:
no
GLP compliance:
yes
Analytical monitoring:
yes
Details on sampling:
- Dissolved organic carbon (DOC) concentrations were determined in a stability study conducted at nominal DOC concentrations of: 5.3, 26.7, 53.3 and 533 mg/L. Samples were taken for analyis 24, 48 and 72 hours after preparation. The DOC concentration of the stock solution used to prepare these concentrations was also determined at the start of the stability study in order to determine the nominal concentrations in the treatments and also on the same occasions during the study.

- Sample storage conditions before analysis: not described
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION

- Method: Nominal test substance concentrations of 34, 62, 107, 186 and 338 mg/L were prepared by dilution of a stock solution of 1000 mg/l. The stock solution was prepared by stirring for 18 h followed by filtration. The measured DOC concentration of the stock solution was equivalent to 564 mg/L of the test substance. Nominal test substance concentrations were based on the measured concentration in the stock solution.

- Controls: Dilution water
Test organisms (species):
Cyprinus carpio
Details on test organisms:
TEST ORGANISM

- Common name: Common carp

- Source: Bio International B.V., Someren, NL

- Length at study initiation (length definition, mean, range and SD): 2.0-3.0 cm

- Feeding during test: none

ACCLIMATION

- Holding conditions: The fish were held in 200 L of water in 300 L glass aquaria at a temperature of 20+/-2°C

- Acclimation period: at least 14 days

- Acclimation conditions: same as test

- Type and amount of food: TRUOVIT at 1% of body weight

- Feeding frequency: Daily

- Health during acclimation (any mortality observed): The fish exhibit normal behaviour and are free from visible signs of disease at the start of the test. Mortality must not exceed 5% in the 7 day period prior to the test.
Test type:
semi-static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
96 h
Hardness:
12ºdH
Test temperature:
19-20.5ºC
pH:
2.0-8.1

Low pH values of 2.5 and 2.0 were measured in the 186 and 338 mg/L treatments at the start of the test. These treatments were not utilised in the test because they would not have been tolerated by the fish.

pH values in the other treatments (34-107 mg/L) ranged between 5.3 and 8.1
Dissolved oxygen:
84-99% ASV
Salinity:
not applicable
Nominal and measured concentrations:
Nominal concentrations: 0(Control), 34, 62, 107, 186 and 338 mg/L. The 186 and 338 mg/L treatments were not utilised in the test because they would not have been tolerated by the fish.

DOC concentrations determined in the stability study were stable after periods of 24, 48 and 72 hours (within +/-20% of nominal). The results are therefore interpreted with reference to nominal concentrations of the substance. However the substance is subject to hydrolysis and it is therefore likely that exposure will predominantly have been to hydrolysis products.
Details on test conditions:
TEST SYSTEM

- Test vessel:

- Type: open aquarium

- Material, size, headspace, fill volume: 20 L with 10 L of test medium

- Aeration: Continuous

- Renewal rate of test solution (frequency/flow rate): Daily

- No. of organisms per vessel: 10

- No. of vessels per concentration (replicates): 1

- No. of vessels per control (replicates): 1

- Biomass loading rate: 0.6 g/L


TEST MEDIUM / WATER PARAMETERS

- Source/preparation of dilution water: Potable water from Gelsenwasser AG


OTHER TEST CONDITIONS

- Adjustment of pH: None

- Photoperiod: 16 h light/8 h dark


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Mortality after 24, 48, 72 and 96 h


TEST CONCENTRATIONS

- Spacing factor for test concentrations: 1.8
Reference substance (positive control):
no
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
> 107 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Remarks:
but exposure is to hydrolysis products
Basis for effect:
mortality
Remarks on result:
other: nominal concentrations based on the measured DOC concentration in the stock solution
Duration:
96 h
Dose descriptor:
LC0
Effect conc.:
107 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Remarks:
but exposure is to hydrolysis products
Basis for effect:
mortality
Remarks on result:
other: nominal concentrations based on the measured DOC concentration in the stock solution
Duration:
96 h
Dose descriptor:
NOEC
Effect conc.:
>= 107 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Remarks:
but exposure is to hydrolysis products
Basis for effect:
mortality
Remarks on result:
other: nominal concentrations based on the measured DOC concentration in the stock solution
Details on results:
- Behavioural abnormalities: none reported

- Mortality of control: 0

- Other adverse effects control: none

- pH effects: low pH values of 2.5 and 2.0 were measured in the 186 and 338 mg/L treatments at the start of the test. These treatments were not utilised in the test because they would not have been tolerated by the fish.
Reported statistics and error estimates:
There were no effects on mortality in the treatments that were not excluded on the grounds of low pH. Statistical analysis of the test results was therefore not required.

Table 1. Test results

Mean initial measured test substance concentration (mg/L) Percentage mortality after 24 hours Percentage mortality after 48 hours Percentage mortality after 72 hours Percentage mortality after 96 hours 
 0 (Control) 0 0 0 0
 34 0 0 0 0
 62 0 0 0 0
 107 0 0 0 0
 186* - - - -
 338* - - - -

*Treatments not continued because of low pH (2.5).

Table 2. Results of analysis of test media in stability study

Nominal concentration (mg/L)* Measured concentration at start of study (mg/L) Measured concentration after 24 hours (mg/L) Measured concentration after 48 hours (mg/L)  Measured concentration after 72 hours (mg/L) 
 5.3  4.7  5.3  5.3  4.5
 26.7  29.4 28.0  27.9 26.4
 53.3  54.8 57.3 57.0 55.3
 533  533 642  599 584
 Stock solution  564 599 589 654

*Based on stock solution concentration at start of study

Validity criteria fulfilled:
yes
Conclusions:
A 96-hour LC50 value of >107 mg/L and NOEC of ≥107 mg/L have been determined for the effects of the test substance on mortality of Cyprinus carpio. The results are interpreted with reference to nominal concentrations of the test substance. However, due to the very rapid hydrolysis rate of the registered substance, it is very likely that the test organisms were exposed to the hydrolysis products of the substance rather than the parent substance.
Endpoint:
short-term toxicity to fish
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
1994-06-27 to 1994-07-01
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Remarks:
The study was conducted according to an appropriate EU method, and in compliance with GLP, and was considered to be reliability 2 (reliable with restrictions) due to the method of analysis being non-specific to the parent substance or the hydrolysis product.
Qualifier:
according to
Guideline:
EU Method C.1 (Acute Toxicity for Fish)
Deviations:
no
GLP compliance:
yes
Analytical monitoring:
yes
Details on sampling:
- Concentrations: 60, 120, 250, 500 and 1000 mg/L.

- Sampling method: Samples of each batch of fresh test media were taken for analyis at the start of the test and after 24, 48 and 72 hours. A sample of old test medium was also taken on one occasion after 24 hours in order to assess stability.

- Sample storage conditions before analysis: not described
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION

- Method: Nominal test concentrations of 60, 120, 250, 500 and 1000 mg/L were prepared by dilution of a stock solution. The stock solution was prepared by stirring for 18 h followed by filtration.

- Controls: Dilution water
Test organisms (species):
Danio rerio (previous name: Brachydanio rerio)
Details on test organisms:
TEST ORGANISM

- Common name: Zebrafish

- Source: West aquarium, Bad Lauterberg, Germany

- Length at study initiation (length definition, mean, range and SD): 3.0 cm +/-0.5 cm

- Feeding during test: none

ACCLIMATION

- Acclimation period: at least 14 days

- Acclimation conditions: same as test

- Type and amount of food: 1% of body weight

- Feeding frequency: Daily

- Health during acclimation (any mortality observed): The fish exhibit normal behaviour and are free from visible signs of disease at the start of the test. Mortality must not exceed 5% in the 7 day period prior to the test.
Test type:
semi-static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
96 h
Hardness:
12ºdH
Test temperature:
20-22ºC
pH:
7.7-8.4
Dissolved oxygen:
66-102% ASV
Salinity:
not applicable
Nominal and measured concentrations:
Nominal concentrations: 0(Control), 60, 120, 250, 500 and 1000 mg/L

Mean measured initial concentrations: 0(Control), 47, 101, 211, 416 and 863 mg/L

The measured concentration declined by between 8 and 26% over a 24 hour period.

The test results are interpreted with reference to mean measured initial concentrations
Details on test conditions:
TEST SYSTEM

- Test vessel:

- Type: open aquarium

- Material, size, headspace, fill volume: 30 L with 10 L of test medium

- Aeration: Continuous

- Renewal rate of test solution (frequency/flow rate): Daily

- No. of organisms per vessel: 10

- No. of vessels per concentration (replicates): 1

- No. of vessels per control (replicates): 1

- Biomass loading rate: 0.13 g/L


TEST MEDIUM / WATER PARAMETERS

- Source/preparation of dilution water: Potable water from Gelsenwasser AG, according to the guideline


OTHER TEST CONDITIONS

- Adjustment of pH: None

- Photoperiod: 16 h light/8 h dark


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Mortality after 24, 48, 72 and 96 h


TEST CONCENTRATIONS

- Spacing factor for test concentrations: 1.8
Reference substance (positive control):
no
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
574 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Remarks:
but exposure is to hydrolysis products
Basis for effect:
mortality
Remarks on result:
other: 416-863
Duration:
96 h
Dose descriptor:
LC0
Effect conc.:
211 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Remarks:
but exposure is to hydrolysis products
Basis for effect:
mortality
Details on results:
- Behavioural abnormalities: none reported

- Mortality of control: 0

- Other adverse effects control: none
Reported statistics and error estimates:
The LC50 values were obtained from a plot of log concentration versus percentage mortality. The confidence interval was defined as the concentrations bounding the LC50 value. The LC0 value was obtained directly from the raw data.

Table 1. Test results

Mean initial measured test substance concentration (mg/L) Percentage mortality after 24 hours Percentage mortality after 48 hours Percentage mortality after 72 hours Percentage mortality after 96 hours 
 0 (Control)  0  0  0  0
 47  0  0  0  0
 101  0  0  0  0
 211  0  0  0  0
 416  0  0  0  10
 863  10  100  100  100

Table 2. Results of analysis of test media

Nominal test substance concentration (mg/L) Measured concentration in fresh medium at start of test (mg/L) Measured concentration in old medium after 24 hours (mg/L) Measured concentration in fresh medium at 24 hours (mg/L)  Measured concentration in fresh medium at 48 hours (mg/L)  Measured concentration in fresh medium at 72 hours (mg/L)  Mean initial measured concentration at 0, 24, 48 and 72 hours (mg/L) 
 60  47  35  52  44  45  47
 120  101  81  108  96  99  101
 250  200  177  240  200  203  211
 500  423  357  462  380  399  416
 1000  806  742  919  -  -  863
Validity criteria fulfilled:
yes
Conclusions:
A 96-hour LC50 value of 574 mg/L and a 96-h LC0 value of 211 mg/L have been determined for the effects of the test substance on mortality of Brachydanio rerio. The results are interpreted with reference to mean measured concentrations of the test substance based on dissolved organic carbon. 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 fish:

WoE 96 hour LC50 >107 mg/l (nominal) (highest concentration tested) (EU Method C.1 (Acute Toxicity for Fish)), read-across from an analogous/structurally related substance, dichloro(3-chloropropyl)methylsilane (CAS 7787-93-1). 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: 96 hour LC50 >86 mg/l as 3-chloropropyl(methyl)silanediol.

WoE 96 hour LC50 574 mg/l (measured DOC concentration) (EU Method C.1 (Acute Toxicity for Fish)), read-across from an analogous/structurally related substance, 3-chloropropyl(diethoxy)methylsilane (CAS 13501-76-3). The observations in this study are attributed to the exposure of test organisms to the hydrolysis products in the test system 3-chloropropyl(methyl)silanediol and ethanol. The result is not expressed in terms of concentration of the hydrolysis product by applying a molecular weight correction, because the result is reported in terms of measured DOC concentration.

Key value for chemical safety assessment

Additional information

No data are available for the registration substance 3-chloropropyl(dimethoxy)methylsilane (CAS 18171-19-2), however data are available from the related substances dichloro(3-chloropropyl)methylsilane (CAS 7787-93-1) and 3-chloropropyl(diethoxy)methylsilane (CAS 13501-76-3). All substances have the same silanol hydrolysis product, 3-chloropropyl(methyl)silanediol. The other hydrolysis products are methanol, hydrochloric acid and ethanol, respectively. In the tests with dichloro(3-chloropropyl)methylsilane (CAS 7787-93-1) and 3-chloropropyl(diethoxy)methylsilane (CAS 13501-76-3), the observations are attributed to the exposure of test organisms to 3-chloropropyl(methyl)silanediol in the test system. There is no basis to expect that hydrochloric acid or ethanol respectively, significantly influenced the results of the tests. The toxicity of hydrochloric acid and ethanol is discussed further in Section 7.0 of the CSR and the RAAF report for ecotoxicity attached in Section 13 of IUCLID.

A 96 hour LC50 value of >107 mg/l has been determined for the effects of dichloro(3-chloropropyl)methylsilane (CAS 7787-93-1) on mortality of Cyprinus carpio. The results are reported in terms of nominal concentrations of the test substance. However, due to the rapid hydrolysis rates it is very likely that the test organisms were exposed to the hydrolysis products 3-chloropropyl(methyl)silanediol and hydrochloric acid. 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 = 191.56) * [CONCENTRATION OF PARENT = >107 mg/l] = >86 mg/l.

A 96 hour LC50 value of 574 mg/l has been determined for the effects of 3-chloropropyl(diethoxy)methylsilane (CAS 13501-76-3) on mortality of Danio rerio. The results are reported in terms of measured concentrations of dissolved organic carbon (DOC). Due to the hydrolysis rate of the test substance (9.5 hours at pH 7) and test media preparation methods (stirring for 18 hours prior to addition of test organisms), it is very likely that the test organisms were exposed to the hydrolysis products 3-chloropropyl(methyl)silanediol and ethanol.

Both tests are interpreted as weight of evidence that the registration substance is not acutely harmful to fish.