Bis(trimethoxysilylpropyl)amine

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1988-08-08 to 1988-08-12

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION

- Method: The test media were prepared by direct dispersion in water with the aid of shielded propeller stirrers.

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM

- Source: Parkwood Trout Farm, Kent, UK.

- Acclimatisation: Stock held since 9 May 1988 and acclimatised to test conditions from 1 - 8 August 1988.

- Temperature: 14 + 20°C.

- Dissolved oxygen: 29.6 mg O2/L.

- Feeding: Commercial trout pellets daily. Discontinued 24 h prior to test.

- Mortalities: <1% in 7 days prior to test.

- Medication: None.

- Mean standard length: 6.6 cm (SD = 0.2cm).

- Mean weight: 4.40 g (SD = 0.35 g).

The fish were slightly larger than the recommended range given in OECD Guidelines No. 203 but this was not considered to have had a significant
effect on the results of the test. These larger fish were preferred for this particular study in view of the strong circulation currents generated by the shielded propeller stirrers necessary to maintain the test dispersion.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

350 mg/L as CaCO3

Test temperature:

14°C

pH:

8.0

Dissolved oxygen:

9.8-10.2 mg/L

Salinity:

Not applicable

Nominal and measured concentrations:

Nominal concentrations: 0 (Control), 100, 180, 320, 560 and 1000 mg/L

Details on test conditions:

- Test vessels: Glass aquaria holding 40 L of test media and fitted with shielded propeller stirrers.

- Experimental design: 5 test concentrations plus 1 control. 10 animals per test concentration.

- Method of initiation: Fish were placed in prepared test media.

- Loading: 1.1 g bodyweight/L

- Photoperiod: 16 h light : 8 h dark

- Temperature: 14+/-1°C.

- Aeration: By shielded propeller stirrers.

- Test concentrations: 100, 180, 320, 560 and 1000 mg/L.

- Medium renewal: Daily

- Duration of exposure: 96 hours

- Criteria of death: Absence of (i) respiratory movement and (ii) response to physical stimulation.

- Dilution water: Laboratory tap water, dechlorinated by the addition of sodium thiosulphate. Total hardness = 350 mg/l as CaCO3. This value is slightly higher than the recommended range but is not considered to have had any significant effects on the results of the test.

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

130 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

but exposure is to hydrolysis products

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

but exposure is to hydrolysis products

Basis for effect:

mortality (fish)

Details on results:

- Mortality of control: None

Reported statistics and error estimates:

Analysis of the mortality data to determine LC50 values was by the method of Thompson, W.R. & Weil, C.S. (1952) Biometrics 8, 51-54.

Sublethal observations / clinical signs:

Table 1. Test results

 

Nominal test 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
100	0	0	0	0
180	0	70	100	100
320	0	100	100	100
560	100	100	100	100
1000	100	100	100	100

 

Validity criteria fulfilled:

yes

Conclusions:

A 96-hour LC50 value of 130 mg/L and a NOEC of 100 mg/L have been determined for the effects of the test substance on mortality of Salmo gairdneri (new name: Oncorhynchus mykiss). The test substance hydrolyses rapidly in water and it is therefore likely that the test organisms were primarily exposed to the hydrolysis products of the substance.

Reference 2

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

13 - 17 May 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Version / remarks:

1992

Qualifier:

according to guideline

Guideline:

other: OECD 23 Guidance Documenton Aquatic Toxicity Testing of Difficult Substance and Mixtures 2000

Qualifier:

according to guideline

Guideline:

other: Fish, Acute Toxicity Test stipulaed in the Testing Methods for New Chemical Substances of Japan, 2011

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: silanol form was measured in all test levels at the start and the end of the exposure. Methanol was measured for the 100 mg/L level (with pH adjustment) and methanol control at the start of the exposure. As the test item hydrolyzes in water and forms silanol and methanol, these both components were measured in the test solutions instead of the test item itself.

- Sampling method: 10 mL of the test solution was taken out from the middle layer of the test vessel.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION

- Method: the test item was added in dilution water while stirring with a magnetic stirrer in Erlenmeyer flask to produce each nominal concentration as silanol form [N,N-bis (3-trihydroxysilylpropyl) amine]. Solutions were stirred with a magnetic stirrer for approx. 2 h. Suspension was filtered with a glass fiber filter and filtrate was re-aerated. In addition the same test solutions for all nominal concentrations were prepared with a final adjustment of the pH to the pH of the dilution water (using HCl).

- Controls: methanol control was made at the same level (75 mg/L) as the theoretical methanol concentration contained in 100 mg/L test solution (theoretical methanol concentration = concentration of silanol form * 32.04 (methanol molecular weight) * 6/257.40 (silanol form molecular weight)).

Test organisms (species):

Oryzias latipes

Details on test organisms:

TEST ORGANISM
- Common name: medaka

- Source: Ceri Kurume (laboratory production)

- Length at study initiation: 2.3 ± 1.2 cm

ACCLIMATION

- Acclimation period: 12 d for pH unadjusted and 40 d for pH adjusted

- Acclimation conditions (same as test or not): dechlorinated tap water, oxygen concentration not less than 80% of air saturation, 24 ± 1 °C, 16 h light/ 8 h dark

- Type and amount of food: fry or carp crumble 2C (Nippon Formula Feed Mfg.), food amount corresponds to 2% of body weight

- Feeding frequency: every day (no feeding 24 h before start of exposure)

- Health during acclimation (any mortality observed): no mortalities 7 d prior to test start

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Test temperature:

pH unadjusted: 23.7 - 24.1 °C
pH adjusted: 24.4 - 24.7 °C

pH:

pH unadjusted: 7.6 - 9.3
pH adjusted: 7.6 - 7.9

Dissolved oxygen:

pH unadjusted: 7.9 - 8.5 mg/L
pH adjusted: 6.4 - 8.1 mg/L

Nominal and measured concentrations:

0 (control), 35, 46, 59, 77, 100 mg/L (nominal, as silanol form) (pH adjusted)
0 (control), 35, 46, 59, 77, 100 mg/L (nominal, as silanol form) (pH unadjusted)

Details on test conditions:

TEST SYSTEM

- Test vessel: 3 L glass tank

- Type (delete if not applicable): closed

- Material, size, headspace, fill volume: transparent plastic lid, fill volume: 2.8 L

- Aeration: yes, conducted gently

- No. of organisms per vessel: 7

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

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

- No. of vessels per methanol control: 1

TEST MEDIUM / WATER PARAMETERS

- Source/preparation of dilution water: dechlorinated tap water, aerated

- Intervals of water quality measurement: at the start of the exposure and every 24 h

OTHER TEST CONDITIONS

- Adjustment of pH: the test was run in two parallels, one with and one without adjustment of pH in order to examine pH effects on fish mortality

- Photoperiod: 16 h light/8 h dark

-Light quality: room light

EFFECT PARAMETERS MEASURED : mortality and abnormalities were observed at 3, 24, 48, 72 and 96 h

TEST CONCENTRATIONS

- Range finding study: yes, pH exceeded 9 at the start of the exposure at test concentrations of 59 - 100 mg/L. Mortalities were observed at these concentrations and therefore solutions with a pH adjustment were additionaly set up, to observe wether effects were caused by pH or by the test item toxicity.

- Test concentrations: 10 - 100 mg/L

- Results used to determine the conditions for the definitive study: based on the results of the range finding test, concentrations between 35 and 100 mg/L were chosen for the definitive study

Reference substance (positive control):

yes

Remarks:

Copper (II) sulfate pentahydrate

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

57 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: pH unadjusted, 95% CI: 48 - 66 mg/L

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: pH adjusted

Details on results:

- Mortality of control: no mortalities

- Mortality of methanol control: no mortalities

Reported statistics and error estimates:

pH unadjusted: LC50 values of 96 h were calculated by Probit analysis.

pH adjusted: LC50 were estimated as the highest test concentration since the mortality over 50% was not observed

Sublethal observations / clinical signs:

Further effect values after 96 h exposure:

pH unadjusted: NOEC (96 h) = 46 mg/L (nominal)

pH adjusted: NOEC (96 h) = 59 mg/L (nominal)

Size of test organisms at the end of the test:

- pH unadjusted: total length: 2.5 ± 0.2 cm, weight: 0.13 ± 0.02 g

- pH adjusted: total length: 2.5 ± 0.1 cm, weight: 0.13 ± 0.01 g

Test item concentrations at the beginning and at the end of the test:

- pH unadjusted: silanol concentrations at test start: 33 - 100 mg/L (87 - 106% of nominal), silanol concentrations at test end: 35 - 88 mg/L (88 - 108% of nominal), methanol concentration at test start in methanol control and test level of 100 mg/L: 81 and 78 mg/L (108 and 103% theoretical formed concentration), respectively.

- pH adjusted: silanol measured concentrations at test start: 39 - 110 mg/L (111 - 119% of nominal), measured concentrations at test end: 37 - 110 mg/L (105 - 111% of nominal)

Table 1: Cumulative mortalities in %.

pH unadjusted
Nominal concentrations [mg/L]	Cumulative mortality in %
	3 h	24 h	48 h	72 h	96 h
Control	0	0	0	0	0
Methanol control	0	0	0	0	0
35	0	0	0	0	0
46	0	0	0	0	0
59	0	0	0	57	86
77	0	0	0	57	86
100	0	14	57	86	100
pH adjusted
Nominal concentrations [mg/L]	Cumulative mortality in %
	3 h	24 h	48 h	72 h	96 h
Control	0	0	0	0	0
Methanol control	0	0	0	0	0
35	0	0	0	0	0
46	0	0	0	0	0
59	0	0	0	0	0
77	0	0	0	0	14
100	0	0	0	0	29

Validity criteria fulfilled:

yes

Conclusions:

A 96 h EC50 value of > 100 mg/L was determined when the pH was adjusted while 96 h EC50 was 57 mg/L when pH was unadjusted. NOEC (96 h) was found to be 46 mg/L (nominal) when pH was unadjusted and 59 mg/L (nominal) when the pH was adjusted to the pH of the dilution water.

Description of key information

LC50 (96 h) > 100 mg/L (nominal, OECD 203) 

Additional information

Two studies are available testing the short-term toxicity of the substance towards fish.

The key study was conducted according to the OECD Guideline 203 and GLP (2013). The test organism Oryzias latipes was exposed in a static test regime to 0 (control), 35, 46, 59, 77 and 100 mg test item/L. The test was run in two parallels, one with and one without adjustment of pH in order to examine pH effects on fish mortality. The test item was analytically monitored by LC-MS and GC % analysis. Due to rapid hydrolysis of the substance, the silanol hydrolysis product was analytically monitored and measured at test start and end. The recovery of the hydrolysis product was in all cases >80%. The study resulted in an LC50 (96 h) of 57 mg/L (nominal) when the pH was not adjusted and an LC50 (96 h) of > 100 mg/L when the pH was adjusted.

The supporting study was also conducted according to the OECD guideline 203 and GLP (1989). The tested organism Oncorhynchus mykiss was exposed to nominal test item concentrations of 100, 180, 320, 560 and 1000 mg/L for 96 h. A semi-static testing regime was chosen. No analytical monitoring was performed in this study. The test determined a 96-hour LC50 value of 130 mg/L.