N-{3-[dimethoxy(methyl)silyl]propyl}butan-1-amine

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:

29 May - 01 Jun 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

2004

GLP compliance:

yes (incl. QA statement)

Remarks:

Staatliches Gewerbeaufsichtsamt Hildesheim, Germany

Analytical monitoring:

yes

Remarks:

LC-MS/MS

Details on sampling:

- Concentrations: 0 (Control), 100 mg/L
- Sampling method: At the start of the exposure and at renewal (0 and 24 h), samples of the fresh media were taken after preparation of the limit concentration and analyzed. At renewal and at the end of the exposure (24 and 48 h), samples of the 24-h old media were taken directly from the test vessels and analyzed.
- Sample storage conditions before analysis: All original samples were stored at room temperature before preparation. Prepared samples were stored in an autosampler at room temperature until analysis.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A bottle was filled with an appropriate amount of the dilution water, which was adjusted to pH 7 ± 0.2 by 1 M HCl, and 111.1 µL/L of the test item were placed by pipette onto the water surface. Test item solution was stirred at approx. 1100 rpm for 24 h at room temperature. After completion of stirring, the clear water phase was removed by siphoning from the approximate center of the water body. The test item solution was checked via laser beam (Tyndall effect) for undissolved test item. The Tyndall effect was positive.
- Differential loading: no
- Controls: Dilution water without test item, adjusted to pH 7 ± 0.2 by 1 M HCl.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Source: laboratory culture (daphnids were cultured in Elendt M4 medium and were fed at least 5 times per week ad libitum with a mix of unicellular green algae, e.g. Pseudokirchneriella subcapitata and Desmodesmus subspicatus. The algae were cultured at the test facility.)
- Age of parental stock: Less than 24 h old daphnids from a healthy stock were used for the study. Juvenile daphnids were removed from the culture vessels at the latest 24 h before the start of the exposure and discarded. The juveniles born within the following period of max. 24 h preceding the exposure were used for the test. No first brood progeny was used for the test.
- Feeding during test: no

ACCLIMATION
- Acclimation period: not necessary since culture medium and test medium are the same

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

-

Test temperature:

18 - 22 °C, constant within ± 1 °C

pH:

7.46 - 8.9 (100 mg/L concentration)
7.09 - 7.57 (Control)

Dissolved oxygen:

6.57 - 9.98

Salinity:

-

Conductivity:

-

Nominal and measured concentrations:

Nominal: 0 (Control), 100 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 50 mL glass beakers (loosely covered with watch glasses)
- Fill volume: 20 ml
- Aeration: no
- Renewal rate of test solution (frequency/flow rate): every 24 h
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: according to guideline
- Culture medium different from test medium: no (both Elendt M4 Medium according to the guideline)
- Intervals of water quality measurement: Prior to the start of the exposure (0 hours) and the water renewal (24 hours), the water quality parameters (i.e. pH-value, dissolved oxygen concentration, temperature, conductivity and total hardness) of the dilution water were measured. At the start of the exposure and at renewal (0 and 24 hours), the water quality parameters of the fresh media (i.e. pH-value, dissolved oxygen concentration) were measured in one additional replicate (without daphnids) of the limit concentration and the control. At renewal and at the end of the exposure (24 and 48 hours), the water quality parameters of the old media were measured in one appropriate replicate (containing daphnids) of the limit concentration and the control.

OTHER TEST CONDITIONS
- Adjustment of pH: yes, adjusted to pH 7 ± 0.2 by addition of 1 M HCl
- Photoperiod: 16/8 hours light/dark cycle
- Light intensity: Diffuse light, light intensity of max. 1500 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): Immobilization was determined in all groups after 24 and 48 hours.

RANGE-FINDING STUDY
- Test concentrations: 1, 10, 100 mg/L
- Results used to determine the conditions for the definitive study: no effects were observed.

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

Details on results:

- Mortality of control: no
- Effect concentrations exceeding solubility of substance in test medium: The limit concentration was visually clear throughout the exposure

Results with reference substance (positive control):

- Results with reference substance valid?
- Relevant effect levels: EC50 (24 h) = 2.07 mg/L

BIOLOGICAL RESULTS.

In the limit concentration with 100 mg/L of the test item no effects on Daphnia magna were observed.

Table 1: Immobilization Rates after 24 and 48 hours of Exposure in the Definitive Test.

Nominal test item concentration [mg/L]	IMMOBILIZATION [%]
	24 hours					48 hours
	Replicates					Replicates
	1	2	3	4	MV	1	2	3	4	MV
100	0	0	0	0	0	0	0	0	0	0
Control	0	0	0	0	0	0	0	0	0	0

ANLYTICAL RESULTS.

The measured concentration of the hydrolysis product in fresh media at the start and at renewal (0 and 24 hours) was 104% and 100%. At the end of each exposure interval the measured concentration was 97% and 102%.

Table 2: Measured Concentrations and Percent of Nominal Concentration of the hydrolysis product of the Test Item N-(n-Butyl)-3-aminopropylmethyldimethoxysilane during the Definitive Test.

Sampling timepoint	0 hours Fresh medium		24 hours Old medium		24 hours Fresh medium		48 hours Old medium
Nominal Test item Concentration [mg/L]	Hydrolysis product of N-(n-Butyl)-3-aminopropylmethyldimethoxysilane
	Meas. conc. [mg/L]	[%]	Meas. conc. [mg/L]	[%]	Meas. conc. [mg/L]	[%]	Meas. conc. [mg/L]	[%]
100	104	104	98.3	98	101	101	101	101
Control	< LOQ	-	< LOQ	-	< LOQ	-	< LOQ	-

VALIDITY CRITERIA:

Table 1: Validity criteria for OECD 202.

Criterion from the guideline	Outcome	Validity criterion fulfilled
In the control, including the control containing the solubilising agent, not more than 10% of the daphnids should have been immobilized.	no daphnids were immobilized in the control	yes
The dissolved oxygen concentration at the end of the test should be ≥ 3 mg/L in control and test vessels.	≥ 6.57 mg/L	yes

Validity criteria fulfilled:

yes

Remarks:

For further details please refer to “Any other information on results incl. tables”.

Conclusions:

In the limit test according to OECD guideline 202, no effects by the tested substance were observed on Daphnia magna up to the concentration of 100 mg/L within 48 h of exposure (EC50 (48 h) > 100 mg/L).

Description of key information

EC50 (48 h) > 100 mg/L (nominal, OECD 202, Daphnia magna)

Additional information

One study is available evaluating the toxicity of N-{3-[dimethoxy(methyl)silyl]propyl}butan-1-amine (CAS 120939-52-8) towards aquatic invertebrates. The study was performed according to OECD 202 and GLP standards with Daphnia magna as the test organism. D. magna was exposed in a semi-static testing regime to a single nominal concentration of 100 mg/L and a control for 48 h. The test item solution was prepared by stirring at approx. 1100 rpm for 24 h at room temperature. The tested substance was analytically monitored. Due to fast hydrolysis of the parent substance, the silanol hydrolysis product was analytically measured. The analytical monitoring was performed via LC-MS/MS and 97 - 104% of the hydrolysis product was recovered during the test. In the limit concentration with 100 mg/L of the test item no effects on Daphnia magna were observed resulting into an EC50 (48 h) of > 100 mg/L.