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Toxicity to microorganisms

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Description of key information

Toxicity to microorganisms: 3hr ASRI EC10 >100 mg/l (loading rate) (OECD 209), read across from a structurally-related substance.

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:
100 mg/L

Additional information

There are no reliable microorganism toxicity data available for chloro(dimethyl)vinylsilane (CAS 1719-58-0), therefore good quality data for the structurally-related substance dichloro(methyl)(vinyl)silane (CAS 124-70-9), have been read across.Both substances hydrolyse very rapidly and have structurally similar silanol hydrolysis products, dimethyl(vinyl)silanol and methyl(vinyl)silanediol, respectively. In view of the very rapid hydrolysis, it is the silanol hydrolysis product that is relevant for environmental risk assessment.

The other hydrolysis product is hydrogen chloride for both substances. Hydrogen chloride is not expected to have adverse effects on microorganisms in a sewage treatment plant, where the pH is maintained within a favourable range.

Chloro(dimethyl)vinylsilane(CAS 1719-58-0) and dichloro(methyl)(vinyl)silane (CAS 124-70-9) 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 (I-2) of alkoxysilanes, silanols, acetoxysilanes and chlorosilanes, etc, where the Si part is of low-biological reactivity, once any hydrolysis is accounted for. Chloro(dimethyl)vinylsilane (CAS 1719-58-0) anddichloro(methyl)(vinyl)silane (CAS 124-70-9) are members of this sub-class.

It is therefore considered valid to read-across the results for dichloro(methyl)(vinyl)silane (CAS 124-70-9) to fill the data gap for the registered substance.Additional information is given in a supporting report (PFA, 2013j) attached in Section 13 of the IUCLID 5 dossier.

 


Table Microorganism toxicity data for substances within the relevant sub-class (I-2) of chemicals

CAS

Chemical Name (CAS Name)

Guideline Number

Test method

Species

PFA Klimisch code

Duration

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

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

001066-40-6

Hydroxytrimethylsilane

OECD 209 and ISO 1892

ASRI

 

2

Uncertain

6670

 

031795-24-1

Potassium methylsilanetriolate

OECD 209

ASRI

 

1a

3 h

 

EC10 >100 mg/l

139147-73-2

Silane, dichlorodicyclopentyl-

OECD 209

ASRI

 

1a

3 hr

>100

 

000124-70-9

Dichloro(methyl)(vinyl)silane

OECD 209

ASRI

 

1a

3hr

>100 mg/l

EC10 >100 mg/l

126990-35-0

Dicyclopentyldimethoxysilane

OECD 209/EU C11/Huls AG method (WOE)

ASRI/ASRI/oxygen consumptionP. putida(WOE)

 

1a/1a/2c -don't use to derive PNEC* (WOE)

 

3 hr; 3hr; 3hr(WOE)

>water solubility; >water solubility; >water solubility (WOE)

 

001000-50-6

Butylchlorodimethylsilane

88/302/EC

ASRI

 

1a

3h

>340

 

013154-25-1

Chlorotri(3-methyl-propyl)silane

OECD 209

ASRI

 

2b

3 hr

>1000 (nominal, parent)

100 (nominal, parent)

005894-60-0

Trichloro(hexadecyl)silane

OECD 209

ASRI

 

1a

3h

>1000

≥1000 mg/l Nitrification control indicated no heterotrophic inhibition of respiration rate

000075-94-5

Trichloro(vinyl)silane

OECD 209

ASRI

 

1a

3hr

>100 mg/l

 

001185-55-3

Trimethoxy(methyl)silane

OECD 209

ASRI

 

1a

3hr

>100 mg/l

EC10 >100 mg/l

017980-47-1

Triethoxyisobutylsilane

OECD 209

ASRI

 

1a

3h

>1000mg/l

≥1000 mg/l

002943-75-1

Triethoxyoctylsilane

OECD 209

ASRI

 

1a

3 hr

>1000

1000 mg/l Nitrification control indicated no heterotrophic inhibition of respiration rate

016068-37-4

4,4,7,7-tetraethoxy-3,8-dioxa-4,7-disiladecane

DIN 38 412, Part 8 (Pseudomonas cell multiplication inhibition test)

growth inhibition test

P. putida

1c

16 h

>8000 mg/l

8000 mg/l

035435-21-3

Triethoxy(2,4,4-trimethylpentyl)silane

OECD 209

ASRI

 

1a

3hr

>100 mg/l

 

087135-01-1

1,6-Bis(trimethoxysilyl)hexane

OECD 209

ASRI

 

1a

3h

>1000 mg/l

 

016415-12-6

Hexadecyltrimethoxysilane

OECD 209

ASRI

 

1a

3 hr

>1000

Nitrification control indicated no heterotrophic inhibition of respiration rate.

018395-30-7

Trimethoxy(2-methylpropyl)silane

Huls AG method

oxygen consumption

P. putida

2c -don't use to derive PNEC*

5.8 h

 

EC10 1.3 ml/l

002768-02-7

Trimethoxyvinylsilane

Huls AG method

oxygen consumption

P. putida

2c -don't use to derive PNEC*

5 h

 

EC10 1.1 ml/l

142877-45-0

Silane, trimethoxy(1,1,2-trimethylpropyl)-

OECD 209

ASRI

 

1a

3 hr

>1000

1000 mg/l

* Emulsifier nonylphenol ethoxylate propoxylate used. Results should be used with caution. Also, reference substance not used.


In the study with dichloro(methyl)(vinyl)silane (CAS 124-70-9), an activated sludge respiration inhibition 3 hour EC10value of >100 mg/l (loading rate) was reported. An EC50 >100 mg/l was reported by the study authors. 6%and 3% inhibition was observed at 100 mg/l in the test. This is considered by the reviewer of this study toindicate an EC10 of >100 mg/l.

The study is considered to be reliability 1 (reliable without restrictions); the read across of the result is considered to be reliability 2 (reliable with restrictions).

References:

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