Registration Dossier
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EC number: 201-251-0 | CAS number: 80-10-4
- 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

Endpoint summary
Administrative data
Description of key information
Additional information
The registered substance is part of a group of organosilicones, the toxicity of which is determined by a non-polar narcosis mechanism of toxicity, and as such log Kow drives toxicity. Substances in this group include alkoxy- and chloro- silanes having secondary features that do not affect the toxicity of the substances. The side chain of the registered substance is an aryl. There is evidence that the phenyl (aryl) group’s toxicity is related to log Kow alone as for other neutral organics and thus does not enhance toxicity. Additional information is given in a supporting report Application of Category - Analogue - QSAR for Reconsile (PFA, 2016b) attached in Section 13 of the IUCLID dossier.
READ-ACROSS JUSTIFICATION
In order to reduce animal testing read-across is proposed to fulfil up to REACH Annex IX requirements for the registered substance from substances that have similar structure and physico-chemical properties. Ecotoxicological studies are conducted in aquatic medium or in moist environments; therefore the hydrolysis rate of the substance is particularly important since after hydrolysis occurs the resulting product has different physico-chemical properties and the structure is altered.
In the following paragraphs the read-across approach fordichloro(diphenyl)silaneis assessed for each surrogate substance taking into account structure, hydrolysis rate and physico-chemical properties.
· Read-across from diphenylsilanediol to dichloro(diphenyl)silane:
Measured data were not available for dichloro(diphenyl)silane for aquatic toxicity. However, as the substance hydrolyses very rapidly (half-life of 10 seconds at pH 7) it is more environmentally relevant to consider the toxicity of the hydrolysis product, diphenylsilanediol (CAS 947-42-2) as organisms will predominately be exposed to the hydrolysis product.Therefore, the hazard assessment for the environment, including sediment and soil compartments, is based on the properties of the hydrolysis product,diphenylsilanediol, in accordance with REACH guidance.
Measured data were available for diphenylsilanediol. The lowest reported effect concentration was an EC50of 9.0 mg/l for the effect on growth rate on the algae Pseudokirchnerella subcapitata. For fish an LC50of 39 mg/l was reported and for invertebrates an EC50of 24 mg/l. These studies were conducted according to OECD Guidelines 201 (Alga, Growth Inhibition Test), 203 (Fish, Acute toxicity test) and 202 (Daphnia sp. Acute Immobilisation Test), respectively and are considered reliable for assessment.
· QSAR:
QSAR predictions for the hydrolysis product diphenylsilanediol confirm the low short-term toxicity of the substance to aquatic organisms. QSAR calculated LC50of 31.6 mg/l for fish, 17.9 mg/l for Daphnia and an EC50of 8.6 mg/l for algae.
· Considerations on the non-silanol hydrolysis products:
Effects on aquatic organisms arising from exposure to hydrochloric acid are thought to result from a reduction in the pH of the ambient environment (arising from an increase in the H+concentration) to a level below their tolerable range. Aquatic ecosystems are characterized by their ambient conditions, including the pH, and resident organisms are adapted to these conditions. The pH of aquatic habitats can range from 6 in poorly-buffered ‘soft’ waters to 9 in well-buffered ‘hard’ waters. The tolerance of aquatic ecosystems to natural variations in pH is well understood and has been quantified and reported extensively in ecological publications and handbooks (e.g. OECD SIDS for CAS 7647-01-0, hydrochloric acid). It is not considered appropriate or useful to derive a single aquatic PNEC for hydrochloric acid because any effects will not be a consequence of true chemical toxicity and will be a function of, and dependent on, the buffering capacity of the environment.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
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