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Ecotoxicological information

Short-term toxicity to fish

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Reference
Endpoint:
short-term toxicity to fish
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1993-10-11 to 1993-10-15
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
EU Method C.1 (Acute Toxicity for Fish)
Version / remarks:
Cited as Directive 92/69/EEC, C.1
GLP compliance:
yes
Analytical monitoring:
yes
Details on sampling:
Freshly prepared test media were sampled at the start of the test and at each medium renewal. Old test medium was sampled at the end of the first 24-hour exposure period.
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION

- Method: The test substance was dissolved in the dilution water and tested without further treatment.
Test organisms (species):
Danio rerio (previous name: Brachydanio rerio)
Details on test organisms:
TEST ORGANISM

- Common name: Zebrafish

- Source: West Aquarium, Bad Lauterburg, Germany

- Length at study initiation: 3.0±0.5 cm

- Feeding during test: none


ACCLIMATION

- Acclimation period: 14-days

- Acclimation conditions: same as test

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

- Feeding frequency: Daily
Test type:
semi-static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
96 h
Hardness:
10.7 deg dH
Test temperature:
20 ± 1 °C
pH:
                               pH           
0 hr    24 hr   48 hr  72 hr   96 hr
Control  7.8      7.8     7.8     7.8      8.4
100 mg/l 7.8     7.7     7.8     7.8      8.3  
Dissolved oxygen:
                    Oxygen content (mg/l)          
0 hr    24 hr   48 hr   72 hr   96 hr   
Control   8.0      7.9      8.4      7.4      8.9
100 mg/l 8.1      7.7      8.2      7.5      8.7    
Salinity:
Not applicable
Nominal and measured concentrations:
Nominal concentrations: 0 (Control) and 100 mg/L

Measured concentrations were within ±20% of nominal.

The test results are reported and interpreted with reference to nominal concentrations.
Details on test conditions:
TEST SYSTEM

- Test vessel: 20 litre aquarium

- Type (delete if not applicable): open

- Aeration: Yes, continuous

- Renewal rate of test solution: daily

- No. of organisms per vessel: 10

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

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


TEST MEDIUM / WATER PARAMETERS

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

OTHER TEST CONDITIONS

- Adjustment of pH: No

- Photoperiod: 16 hours light, 8 hours dark


EFFECT PARAMETERS MEASURED: Daily mortalities


TEST CONCENTRATIONS

- Spacing factor for test concentrations: Limit test
Reference substance (positive control):
no
Key result
Duration:
96 h
Dose descriptor:
NOEC
Effect conc.:
>= 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality (fish)
Key result
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality (fish)
Details on results:
- Behavioural abnormalities: not reported

- Mortality of control: none

- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: not reported
Reported statistics and error estimates:
There were no effects on mortality and therefore statistical analysis of the results was not required.
Sublethal observations / clinical signs:

The measured concentration of the test substance after 0, 24, 48, and 72 hours was determined to be 119, 103/110 (indicating stability within 24 hours), 105, and 102 mg/l, respectively, based on Dissolved Organic Carbon measurements.



The deviation of the analytical results was within 20%, such that the concentrations were reported as nominal.


                       Concentration (mg/l)
         0 hr    24 hr       48 hr   72 hr    
         119     103*/110   105     102  
*= 24-hour stability control    

No mortalities were reported in the control and 100 mg/L test medium concentration 24, 48, 72 and 96 hours during the test.
    

Validity criteria fulfilled:
yes
Conclusions:
A 96-hour LC50 value of >100 mg/L and a NOEC of ≥100 mg/L have been determined for the effects of the test substance on mortality of Brachydanio rerio (new name: Danio rerio). It is likely that the test organisms were predominantly exposed to the hydrolysis products of the substance.

Description of key information

96-hour LC50 >100 mg/l (measured based on DOC) (highest concentration tested) (EU Method C.1). The observations in this study are attributed to the exposure of test organisms to the hydrolysis products in the test system. The LC50 is equivalent to >79 mg/l when expressed in terms of the silanol hydrolysis product.

Key value for chemical safety assessment

Additional information

A 96 hour LC50 value of >100 mg/l (measured) (highest concentration tested) has been determined for the effects of the registered substance (3-chloropropyl)trimethoxysilane (CAS 2530-87-2) on mortality of Brachydanio rerio (Hüls, 1994). In view of the test media preparation method and exposure regime it is likely that the test organisms were exposed predominantly to the hydrolysis products of the tested substance. The nominal test concentrations are supported by DOC analysis. The results may be expressed in terms of concentration of the silanol hydrolysis product, (3 -chloropropyl)silanetriol, by applying a molecular weight correction: (MW of silanol = 156.64 / MW of parent = 198.72) * 100 mg/l = 78.8 mg/l.

 

Above a concentration of approximately 1000 mg/l, dimeric / oligomeric, cyclic or cross-linked condensation products could potentially form over time in the aqueous test media. There was no report of undissolved material (parent substance or precipitated products) indicated in the study report for this test. 

Refer to the discussion in the Section 6 endpoint summary (Section 7.0 of CSR) for further discussion of the approach to chemical safety assessment for this registration substance.