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Toxicity to microorganisms

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Description of key information

Toxicity to microorganisms: 3 hour EC50 >1000 mg/l, NOEC ≥1000 mg/l (OECD 209), read-across from an analogous substance.

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:
1 000 mg/L

Additional information

There are no reliable microorganism toxicity data available for[3-(2,3-epoxypropoxy)propyl]diethoxy(methyl)silane(CAS 2897-60-1), therefore good quality data for the analogous/structurally-related substance, [3-(2,3-epoxypropoxy)propyl]triethoxysilane (CAS 2602-34-8), have been read across.

Both substances hydrolyse rapidly and have silanol hydrolysis products that share epoxide as a functional group. In view of the hydrolysis, it is the silanol hydrolysis product that is relevant for environmental risk assessment. The other hydrolysis product is ethanol in both cases.[3-(2,3 -Epoxypropoxy)propyl]diethoxy(methyl)silane(CAS 2897-60-1) and [3-(2,3-epoxypropoxy)propyl]triethoxysilane (CAS 2602-34-8) are within an analogue group of substances within which, in general, there is no evidence of significant toxicity to microorganisms. This analogue group for the toxicity to microorganisms endpoint consists of a number of sub-classes of substances (based on structure/functionality) with different main codes (used to represent the different sub-classes). However, read-across is carried out between substances with the same main code in most cases. The table below presents microorganism toxicity data available for substances within the sub-class III-12 of epoxyalkyl alkoxysilanes.

[3-(2,3-epoxypropoxy)propyl]diethoxy(methyl)silane(CAS 2897-60-1) and [3 -(2,3-epoxypropoxy)propyl]triethoxysilane (CAS 2602-34-8) are members of this sub-class. It is therefore considered valid to read-across the results for [3-(2,3-epoxypropoxy)propyl]triethoxysilane (CAS 2602-34-8) to fill the data gap for the registered substance. Additional information is given in a supporting report (PFA, 2013j) attached in Section 13.

Table: Microorganism toxicity data available for substances within the relevant sub-class III-12 of chemicals

CAS

Name

Main code

Result: E(I)C50 (mg/l)

Result: NOEC (or EC10/ EC20) (mg/l)

Guideline Number

Test method

Species

Duration

Reliability

10217-34-2

triethoxy-[2-(7-oxabicyclo[4.1.0]hept-3-yl)ethyl]silane

III-12

 

<10% inhibition at 100 mg/l

OECD 209

ASRI

 

30 minutes

1

2530-83-8

[3-(2,3-epoxypropoxy)propyl]trimethoxysilane

III-12

>100 mg/l

 

OECD 209

ASRI

 

3 h

1

2602-34-8

[3-(2,3-epoxypropoxy)propyl]triethoxysilane

III-12

>1000 mg/l

≥1000

OECD 209

ASRI

 

3 h

1

In the study with [3-(2,3-epoxypropoxy)propyl]triethoxysilane (CAS 2602-34-8), an activated sludge respiration inhibition 3 hour EC50value of>1000 mg/l and NOEC≥1000 mg/lwere reported.

References:

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

PFA (2013j). Peter Fisk Associates, STP Microorganism toxicity Main Analogue Group report, PFA.300.003.006