3-(triethoxysilyl)propanethiol

Toxicity to soil macroorganisms except arthropods

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to soil macroorganisms except arthropods: short-term

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1996-02-29 to 1996-03-14

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The study was conducted according to an EU method, and in compliance with GLP, however no analytical monitoring was undertaken.

Qualifier:

according to guideline

Guideline:

EU Method C.8 (Toxicity for Earthworms: Artificial Soil Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

Eisenia fetida

Animal group:

annelids

Details on test organisms:

TEST ORGANISM

- Common name: Earthworm, Eisenia foetida foetida

- Source: Eisenia GmbH und Co, Wiesbaden, Germany

- Age at test initiation (mean and range, SD): 2 months

- Weight at test initiation (mean and range, SD): 300 - 600 mg

Study type:

laboratory study

Substrate type:

other: quartz sand

Limit test:

yes

Total exposure duration:

14 d

Test temperature:

20 +/-2 ºC

pH:

5.7

Moisture:

40%

Details on test conditions:

TEST SYSTEM

- No. of organisms per container (treatment): 10

- No. of replicates per treatment group: 4

- No. of replicates per control: 4

SOURCE AND PROPERTIES OF SUBSTRATE (if soil)

- Composition (if artificial substrate): Quartz sand

OTHER TEST CONDITIONS

- Photoperiod: Daylight

- Light intensity: ca. 400 Lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Mortality after 7 and 14 days exposure

VEHICLE CONTROL PERFORMED: no

TEST CONCENTRATIONS

- Limit test at 1000 mg/kg

Nominal and measured concentrations:

Nominal: 1000 mg/kg

Reference substance (positive control):

no

Duration:

14 d

Dose descriptor:

LC50

Effect conc.:

> 1 000 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

>= 1 000 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Details on results:

- Mortality at end of exposure period: 0

Reported statistics and error estimates:

No toxic effects on survival and growth were observed in the test and therefore statistical analysis of the results was not required.

Validity criteria fulfilled:

yes

Conclusions:

A reliable 14-day LC50 of >1000 mg/kg dry weight has been reported for the test substance to Eisenia foetida. A NOEC of ≥1000 mg/kg dry weight was also determined in the test.

Reference 2

Endpoint:

toxicity to soil macroorganisms except arthropods: short-term

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

See IUCLID Section 6.0, CSR Section 7.0, and the RAAF report for ecotoxicity attached in IUCLID Section 13 and Annex 5 of the CSR, for justification of read-across.

Reason / purpose for cross-reference:

read-across source

Duration:

14 d

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Description of key information

A 14-day LC₅₀ value of >1000 mg/kg dry weight has been determined for the effects of the read-across substance, 3-(trimethoxysilyl)propane-1-thiol (CAS 4420-74-0) on the mortality of Eisenia fetida, based on nominal concentrations. This value is equivalent to 786 mg/kg dry weight when expressed in terms of the silanol hydrolysis product 3-(trihydroxysilyl)propanethiol.

Additional information

There are no reliable soil macroorganism except arthropods toxicity data available for 3-(triethoxysilyl)propanethiol (CAS 14814-09-6), therefore good quality data for an appropriate structural analogue, 3-(trimethoxysilyl)propane-1-thiol (CAS 4420-74-0) have been read across. Both substances have hydrolysis half-lives which indicate that, under conditions relevant to ecotoxicity assessment, both will hydrolyse to 3-(trihydroxysilyl)propanethiol over the course of the test. The other hydrolysis products are ethanol and methanol respectively; the properties of these substances are well characterised. Methanol is non-toxic to the environment and it is considered unlikely that its presence significantly affected the results of the test performed with the read-across substance. The non-silanol hydrolysis product, ethanol, is not expected to contribute to toxicity to terrestrial organisms. 

 

A 14-day LC₅₀ value of >1000 mg/kg dry weight has been determined for the effects of 3-(trimethoxysilyl)propane-1-thiol (CAS 4420-74-0) on the mortality of Eisenia fetida, based on nominal concentrations of the substance (Scholz, 1996). The result was obtained under static test conditions. 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 results may be expressed in terms of the concentration of the hydrolysis product, 3-(trihydroxysilyl)propanethiol, by applying a molecular weight correction (MW of silanol = 154.26/ MW of parent = 196.34) * (concentration of parent = 1000 mg/kg dry weight) = >786 mg/kg dry weight

 

The study was considered to be reliability 2 (reliable with acceptable restrictions).