Triethoxy(3-isocyanatopropyl)silane

Long-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Not reported

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

Guideline study with acceptable restrictions. The study was not conducted in compliance with GLP and exposure concentrations were not measured.

Qualifier:

no guideline followed

Principles of method if other than guideline:

The study consisted of triplicate runs of a 21-day test. Each run consisted of duplicates for control and all test concentrations. Each duplicate started with five 24 to 48 hour old Daphnia magna. Concentrations of 0.01, 0.03, 0.1, 0.3 and 1.0 ppm were selected for the test. First generation Daphnia mortality was recorded throughout the test and their reproductive function was assessed by counting the total number of young produced through day 21.

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

The substance was added directly to 600 mL beakers, each containing 400 ml of hard reconstituted fresh water.

Test organisms (species):

Daphnia magna

Details on test organisms:

- Source: The test daphnids were from a laboratory culturing. The original colony of Daphnia magna was obtained through the Dow Chemical Company, which obtained their colony from the Duluth Laboratory of the United States Environmental Protection Agency.

- Culture medium: The colonies were maintained under static conditions in reconstituted hard water (EPA 660/3-75-009) made-up from glass-distilled water. Before culture inoculation, the reconstituted water was aerated for 2-4 hours.

- Culture conditions: The colonies were maintained in five-gallon glass aquaria under approximately 1000 foot-candle illumination (18/6 hour light/dark) in an environmental chamber designed to maintain 22+/-1°C.

- Feeding: The food for the Daphnia. magna was prepared each week by blending 0.25 g alfalfa meal, 4.0 g trout chow and 400 mL distilled water. This solution was allowed to settle and the supernatant used as food.

- Test organisms; A number of egg-bearing daphnia were isolated prior to each test for a period of 24 to 48 hours. Five 24 to 48 hours old.
Daphnia magna produced in the period prior to the test were introduced into each test concentration along with the untreated control group.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

21 d

Hardness:

No data

Test temperature:

22+/-1°C

pH:

No data

Dissolved oxygen:

No data

Salinity:

Not applicable

Nominal and measured concentrations:

Nominal concentrations: 0 (Control), 0.01, 0.03, 0.1, 0.3 and 1.0 ppm

Details on test conditions:

Five 24 to 48 hour old Daphnia magna were introduced into each test concentration along with the untreated control group.

The test consisted of triplicate runs of the 21-day test. Each run consisted of duplicates for control and all test concentrations, each duplicate started with five 24 to 48 hour old Daphnia magna.

The daphnia were fed 0.25 ml of Daphnia food each day except weekends throughout the 21-day study.

Observations were made each day for each of the test concentrations and control groups for mortalities and young produced.

The daphnia were transferred to fresh test and control vessels weekly throughout the 2l-day study.

Survival of the first generation daphnids was recorded throughout the test. The reproductive function of the first generation daphnia was assessed by counting the total number of young produced through day 21.

Comparison between test vessels and controls were made for first generation survival, fecundity, and survival of the second generations. General observations of behaviour and abnormalities were also made.

Reference substance (positive control):

no

Key result

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

>= 1 other: ppm

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: reproduction and mortality

Details on results:

Control parental Daphnia survival after 21 days: 96.7%

There were no statistically significant differences in survival and reproductive output between the Controls and any of the treatments.

Reported statistics and error estimates:

The levels of effect on survival and reproduction were insufficient to determine ECx values.

Differences in reproductive output were assessed by t test with p<0.05

Table 1. Test results

 

Nominal concentration (ppm)	Survival of parental daphnia (%)	Total young produced +/-Stand Dev	Young produced per female +/-Stand Dev	Initial survival of offspring (%)
0 (Control)	96.7	52.7+/-25.3	10.72+/-4.81	99.7
0.01	100	47.7+/-23.3	9.53+/-4.66	98.3
0.03	100	46.0+/-28.1	9.20+/-5.63	100
0.1	100	52.2+/-25.3	10.43+/-5.07	99.7
0.3	100	44.2+/-29.0	8.83+/-5.81	99.6
1.0	90	33.5+/-17.1	6.93+/-3.19	99.5

 

Validity criteria fulfilled:

yes

Conclusions:

A 21-day NOEC of ≥1 ppm has been determined for the effects of the test substance on survival and reproduction of Daphnia magna. The results are expressed relative to nominal concentrations of the test substance. However the substance is subject to rapid hydrolysis and under the test conditions it is therefore likely that exposure will have been to its hydrolysis products (methanol and trisilanols).

Description of key information

(21-day) NOEC: ≥1 ppm survival and reproduction, Daphnia magna, read across from N-(3-(trimethoxysilyl)propyl)ethylenediamine (CAS 1760-24-3).

Additional information

There are no reliable long-term invertebrate toxicity data available for triethoxy(3-isocyanatopropyl)silane (CAS 24801-88-5), therefore good quality data for an appropriate structural analogue, N-(3-(trimethoxysilyl)propyl)ethylenediamine (CAS 1760-24-3), have been read across.

Both substances rapidly hydrolyse to structurally similar hydrolysis products, 3-aminopropylsilanetriol and N-(3-(trihydroxysilyl)propyl)ethylenediamine, respectively. The other hydrolysis products are ethanol and methanol, respectively, and are not considered likely to contribute to effects observed in studies.

A 21-day NOEC of ≥1 ppm (≥1 mg/l) has been determined for the effects of N-(3-(trimethoxysilyl)propyl)ethylenediamine (CAS 1760-24-3) on survival and reproduction of Daphnia magna. The results are expressed relative to nominal concentrations of the test substance. However the substance is subject to rapid hydrolysis and under the test conditions it is therefore likely that exposure will have been to its hydrolysis products (methanol and N-(3-(trihydroxysilyl)propyl)ethylenediamine).