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EC number: 223-888-3 | CAS number: 4109-96-0
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data
Toxicity to microorganisms
Administrative data
Link to relevant study record(s)
Description of key information
Toxicity to microorganisms: 3 hour EC50 > 100 mg/l (OECD 209), read-across from an analogous substance.
Key value for chemical safety assessment
Additional information
There are no reliable microorganism toxicity data available for dichlorosilane (CAS 4109-96-0). A toxicity to microorganisms study with dichlorosilane is considered technically unfeasible because the substance is a gas at normal temperature and pressure and is expected to react violently and rapidly with water. This violent and rapid reaction of the gas with water would render aquatic ecotoxicology testing impossible and thus testing is waived on the basis of the technical difficulty to conduct such tests.
However, good quality data for the analogous substance, tetraethyl orthosilicate (CAS 78-10-4), have been read across as supporting evidence that the silanol hydrolysis product is not toxic and adding to the weight of evidence for not doing any further testing. Both substances hydrolyse rapidly to monosilicic acid. Tetraethyl orthosilicate hydrolyses with a half-life of 4.4 hours at pH7 and 25°C to give monosilicic acid and ethanol. Dichlorosilane hydrolyses with a half-life of approximately 5 seconds (as a worst case) at 25°C and pH 7 (analogue read-across). This half-life relates to degradation of the parent substance to give silanediol and HCl.
The Si-H bonds of silanediol are expected to react rapidly (<12 hours at 25°C and pH 7) to produce hydrogen and monosilicic acid.
In view of the rapid hydrolysis, it is the silanol hydrolysis product that is relevant for environmental risk assessment.
Dichlorosilane (CAS 4109-96-0) and tetraethyl orthosilicate (CAS 78-10-4) 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 for substances within the sub-class I-4 of Silicon without carbon attached (“(Poly)silicic acid producers”). Dichlorosilane (CAS 4109-96 -0) and tetraethyl orthosilicate (CAS 78-10-4) are members of this sub-class.
It is therefore considered valid to read-across the results for tetraethyl orthosilicate (CAS 78-10-4) 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 dossier.
Table: Microorganism toxicity data for substances within the relevant sub-class I-4 of chemicals
CAS |
Name |
Main code |
Result: E(I)C50 (mg/l) |
Result: NOEC (Or EC10/EC20) (mg/l) |
Guideline |
Test method |
Species |
Duration |
Klimisch code |
000078-10-4 |
Tetraethyl orthosilicate |
I-4-Q |
>100 mg/l |
|
OECD 209 |
ASRI |
|
3hr |
1 |
018765-38-3 |
Tetrakis(2-butoxyethyl) orthosilicate |
I-4-Q |
|
EC10 >1.7 ml/l |
Huls AG method |
oxygen consumption |
P. putida |
5 h |
2 |
068412-37-3 |
Silicic acid (H4SiO4), tetraethyl ester, hydrolyzed |
I-4-Q |
|
EC10 >2 ml/l |
Huls AG method |
oxygen consumption |
P. putida |
5 h |
2 |
In the study with tetraethyl orthosilicate (CAS 78 -10 -4), an activated sludge respiration inhibition (ASRI) 3 hour EC50value of >100 mg/l was reported.
The hydrolysis rate for tetraethyl orthosilicate is 4.4 hours at pH7 and 25°C, and so it is likely to hydrolyse to monosilicic acid to a lesser extent than dichlorosilane would hydrolyse over the timescale of the ASRI test.Therefore, microorganisms toxicity data for Silicic acid (H4SiO4), tetraethyl ester, hydrolysed (CAS 68412-37-3), which is a member of the same
sub-class I-4 of Silicon without carbon attached (“(Poly)silicic acid producers”)
A 5.42 hour EC10 of >2 ml/l for toxicity to Pseudomonas putida was determined for silicic acid (H4SiO4), tetraethyl ester, hydrolysed in a reliable study conducted according to
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