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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 1994-10-15
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 203 (Fish, Acute Toxicity Test)
Principles of method if other than guideline:
DIN 38412 Part 1; EG Guideline 92/69 C.1; OECD Guideline 203, 1984
GLP compliance:
yes
Analytical monitoring:
yes
Details on sampling:
The only treatment was sampled at the start of the test
Vehicle:
no
Details on test solutions:
A test medium was prepared at a nominal concentration of 1.0 g/L by mixing for 18 hours followed by filtration. Analysis of the medium showed it to contain 934 mg/L of the substance.
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:
10.7ºdH (18 mg/L as CaCO3)
Test temperature:
20-21ºC
pH:
7.8-8.4 in Control

8.2-9.3 in Treatment
Dissolved oxygen:
8.0-8.9 mg/L in Control

7.8-9.0 mg/L in Treatment
Salinity:
Not applicable
Nominal and measured concentrations:
Nominal concentrations: 0 (Control) and 1000 mg/L

Measured concentrations: 880 mg/l at 0 hours; 922/947 mg/l at 24 hours; 885 mg/l at 72 hours; average value of 934 mg/l (water  filtered initial solution).

Measured concentration in treated media: 934 mg/L
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
Duration:
96 h
Dose descriptor:
NOEC
Effect conc.:
>= 934 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
mortality
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
> 934 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
mortality
Details on results:
- Mortality of control: 0

· Abnormal responses:  None reported
Reported statistics and error estimates:
No effects were observed in the test and therefore statistical analysis was not required.

No effects were observed in Control or treated media.

Validity criteria fulfilled:
yes
Conclusions:
A 96-hour LC50 of >934 mg/L and NOEC of =934 mg/L have been determined for the effects of the test substance on mortality of Brachydanio rerio. It is likely that the test organisms were exposed predominantly to the hydrolysis products of the substance.

Description of key information

96-hour LC50: >934 mg/l, mortality of Brachydanio rerio; equivalent to >579 mg/l as 3-aminopropylsilanetriol.

Key value for chemical safety assessment

LC50 for freshwater fish:
579 mg/L

Additional information

The only available test data for short-term toxicity of 3-(trimethoxysilyl)propylamine (CAS 13822-56-5) to fish are of non-assignable reliability, taken from a secondary data source. An LC50 value of 1264 mg/l was reported.

 

Reliable data are however available from appropriate structural analogues, 3-aminopropyltriethoxysilane (CAS 919-30-2) and 3-(trimethoxysilyl)propyl isocyanate (CAS 15396-00-6), which react in water to the same hydrolysis product as the registration substance, 3-aminopropylsilanetriol. Condensation reactions leading to insoluble oligomers/polymers can be a problem for ecotoxicity testing with substances generating silanols. This has been considered for these substances and is not considered to have been an issue at the test media stock concentration up 1000 mg/l in the key studies (PFA, 2016am).

 

A 96-hour LC50 of >934 mg/l (measured DOC concentration) (highest concentration tested) have been determined for the effects of 3-aminopropyltriethoxysilane on mortality of Brachydanio rerio (tested as Danio rerio), in accordance with OECD Test Guideline 203.

The test substance is susceptible to hydrolysis and it is likely that the test organisms were exposed to the hydrolysis products of the substance.

The results may be expressed in terms of concentration of the hydrolysis product, 3-aminopropylsilanetriol, by applying a molecular weight correction: (MW of silanol = 137.21 / MW of parent = 221.37) * >934 mg/l = >579 mg/l. This value is read across to 3-(trimethoxysilyl)propylamine (CAS 13822-56-5) without further correction.

 

These findings are supported by a 96-hour LC50 in rainbow trout of >100 mg/l (nominal concentration) (highest concentration tested), determined for 3-(trimethoxysilyl)propyl isocyanate (CAS 15396-00-6), in accordance with OECD Test Guideline 203. For this substance the isocyanate group is very rapidly hydrolysed to the corresponding amine, which is structurally identical to the registration substance (half-life of minutes or less), and further hydrolysis of the alkoxy groups proceeds at a slower rate (half-life of 2.6 hours at pH 7 and 20-25 °C, estimated) to 3-aminopropylsilanetriol and methanol.

 

Refer to the IUCLID Section 6 endpoint summary (Section 7.0 of the CSR) for further discussion of the approach to chemical safety assessment for this registration substance, and justification for read-across used.