Triethoxy(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl)silane

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1997-04-24

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

activated sludge of a predominantly domestic sewage

Test type:

static

Water media type:

freshwater

Total exposure duration:

3 h

Test temperature:

18-22°C were hold by cooling the water in the incubation vessel with ice.

At the beginning of incubation: 18-19°C

During the determination of oxygen content: 18.8-19.9°C

Dissolved oxygen:

Control 1: 38.93 mg O2/l*h
Control 2: 39.20 mg O2/l*h

The difference between control 1 and 2 does not exceed 15% (i.e. 0.7%)

Reference substance (positive control):

yes

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 1 300 mg/L

Details on results:

In the tested concentration range of 67, 133, 267, 534, and 1334 mg/l there was no inhibitory dose-effect-level

Results with reference substance (positive control):

A positive control test with 3, 5-dichlorophenol yielded an EC50 of 7.3 mg/l, which is within the accepted range of 5 to 30 mg/l required by the guideline for a valid study.

Validity criteria fulfilled:

yes

Conclusions:

An activated sludge respiration inhibition 3hr EC50 value of >1300 mg/l was determined in a reliable study conducted according to an appropriate test protocol, and in compliance with GLP. This indicates that the test substance was not toxic to waste water (activated sludge) bacteria at a nominal concentration of 1300 mg/l.

Description of key information

Toxicity to microorganisms: Activated sludge respiration inhibition 3-hour EC50 > 1300 mg/l (highest concentration tested) (OECD 209).

Additional information

An activated sludge respiration inhibition 3-hour EC₅₀ value of >1300 mg/L was determined in a reliable study conducted according to an appropriate test protocol, and in compliance with GLP. This indicates that the test substance, [2-(perfluorohexyl)ethyl]triethoxysilane (CAS 51851-37-7, EC 257-473-3), was not toxic to waste water (activated sludge) bacteria at a nominal concentration of 1300 mg/l.

[2-(Perfluorohexyl)ethyl]triethoxysilane in contact with water, hydrolyses moderately to form [2-(perfluorohexyl)ethyl]silanetriol and ethanol. Refer to IUCLID Section 6.1 and Section 7.1 of the CSR for discussion of the surface active properties of the parent substance, silanol hydrolysis product and condensation products and further discussion of the hydrolysis rates of the parent substance.

Ethanol does not have adverse effects on microorganisms (OECD, 2004).

Reference:

OECD (2004): SIDS Initial Assessment Report for SIAM 19, Berlin, Germany, 19-22 October 2004, Ethanol, CAS 64-17-5.