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EC number: 222-123-0 | CAS number: 3353-69-3
- 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 aquatic algae and cyanobacteria
Administrative data
Link to relevant study record(s)
Description of key information
Short-term toxicity to algae: 72 hr EC50 >100 mg/l (nominal) (highest concentration tested) (OECD 202), read-across from a structurally related substance, 1,6-bis(trimethoxysilyl)hexane (CAS 87135-01-1). The observations in this study are attributed to the exposure of test organisms to the hydrolysis products in the test system. The EC50 is equivalent to >74 mg/l when expressed in terms of the silanol hydrolysis product.
Key value for chemical safety assessment
- EC10 or NOEC for freshwater algae:
- 74 mg/L
Additional information
There are no reliable short-term toxicity to algae data available for 1,2-bis[dichloro(methyl)silyl]ethane (CAS 3353-69-3), therefore good quality data for an appropriate structural analogue, 1,6-bis(trimethoxysilyl)hexane (CAS 87135-01-1), have been read across. Both substances have structurally similar silanol hydrolysis products, 1,2-bis[dihydroxy(methyl)silyl]ethane and 1,6-bis(trihydroxysilyl)hexane respectively. The other hydrolysis products are hydrogen chloride and methanol, respectively. In the test with 1,6-bis(trimethoxysilyl)hexane, the observations are attributed to the exposure of test organisms to 1,6-bis(trihydroxysilyl)hexane in the test system. There is no basis to expect that methanol significantly influenced the results of the test. The toxicity of methanol is discussed further in the ecotoxicological information overview endpoint summary (additional information).
A 72-hour E(L)C50 value of >100 mg/l and NOEC of ≥100 mg/l (nominal) (highest concentration tested) have been determined for the effects of 1,6-bis(trimethoxysilyl)hexane (CAS 87135-01-1) on growth rate of Pseudokirchneriella subcapitata. In view of the test media preparation method and exposure regime (3 h stirring prior to start of exposure; static exposure regime; pH 7.4 -8.9) it is likely that the test organisms were exposed predominantly to the hydrolysis products of the tested substance, although a low proportion of parent substance may have been present at the beginning of the exposure period.
The results may be expressed in terms of concentration of the hydrolysis product, 1,6-bis(trihydroxysilyl)hexane, by applying a molecular weight correction: (MW of silanol = 242.38 / MW of parent = 326.54) * >100 = >74 mg/l. This value is read across to 1,2-bis[dihydroxy(methyl)silyl]ethane without further correction.
Above a concentration of approximately 1000 mg/l, dimeric / oligomeric, cyclic or cross-linked condensation products could potentially form over time in the aqueous test media. No evidence of undissolved material (parent substance or precipitated products) is indicated in the study report for this test.
Test data have also been read-across from 4,4,7,7-tetraethoxy-3,8-dioxa-4,7-disiladecane (CAS 16068-37-3) which has a structurally similar silanol hydrolysis product, 1,1,1,4,4,4-hexahydroxy-1,4-silabutane, to that of the registration substance. The other hydrolysis product is ethanol. 4,4,7,7-Tetraethoxy-3,8-dioxa-4,7-disiladecane has a slower hydrolysis half-life (36 h at pH 7) than 1,2-bis[dichloro(methyl)silyl]ethane. However, test solution preparation time during the algae test involved 24 hours stirring, as well as static test conditions, therefore the algae would have been exposed to a mixture of parent substance and hydrolysis products. It is therefore considered conservative to read-across from 4,4,7,7-tetraethoxy-3,8-dioxa-4,7-disiladecane.
A 72-hour E(L)C50 value of >100 mg/l (highest concentration tested) and EC10 of 92.9 mg/l (nominal) have been determined for the effects of 4,4,7,7-tetraethoxy-3,8-dioxa-4,7-disiladecane (CAS 16068-37-3) on growth rate of Pseudokirchneriella subcapitata. In view of the test media preparation method and exposure regime (24 h stirring prior to start of exposure; static exposure regime; pH 7.82 - 8.23) it is likely that the test organisms were exposed to a mixture of the parent substance and the hydrolysis products.
The results may be expressed in terms of concentration of the hydrolysis product, 1,1,1,4,4,4-hexahydroxy-1,4-silabutane, by applying a molecular weight correction: (MW of silanol = 186.27 / MW of parent = 354.59) * EC50 >100 = >53 mg/l, and EC10 92.9 = 49 mg/l. This value is read across to 1,2-bis[dihydroxy(methyl)silyl]ethane without further correction.
Refer to the discussion in the Section 6 endpoint summary (Section 7.0 of CSR) for further discussion of the approach to chemical safety assessment for this registration substance, and justification for read-across used.
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