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Diss Factsheets
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EC number: 208-764-9 | CAS number: 541-02-6
- 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
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Ecotoxicological Summary
Administrative data
Hazard for aquatic organisms
Freshwater
- Hazard assessment conclusion:
- PNEC aqua (freshwater)
- PNEC value:
- 1.2 µg/L
- Assessment factor:
- 10
- Extrapolation method:
- assessment factor
Marine water
- Hazard assessment conclusion:
- PNEC aqua (marine water)
- PNEC value:
- 0.12 µg/L
- Assessment factor:
- 100
- Extrapolation method:
- assessment factor
STP
- Hazard assessment conclusion:
- PNEC STP
- PNEC value:
- 10 mg/L
- Assessment factor:
- 100
- Extrapolation method:
- assessment factor
Sediment (freshwater)
- Hazard assessment conclusion:
- PNEC sediment (freshwater)
- PNEC value:
- 11 mg/kg sediment dw
- Assessment factor:
- 10
- Extrapolation method:
- assessment factor
Sediment (marine water)
- Hazard assessment conclusion:
- PNEC sediment (marine water)
- PNEC value:
- 1.1 mg/kg sediment dw
- Assessment factor:
- 100
- Extrapolation method:
- assessment factor
Hazard for air
Air
- Hazard assessment conclusion:
- no hazard identified
Hazard for terrestrial organisms
Soil
- Hazard assessment conclusion:
- PNEC soil
- PNEC value:
- 2.54 mg/kg soil dw
- Assessment factor:
- 50
- Extrapolation method:
- assessment factor
Hazard for predators
Secondary poisoning
- Hazard assessment conclusion:
- PNEC oral
- PNEC value:
- 16 mg/kg food
- Assessment factor:
- 90
Additional information
The hydrolysis half-life of decamethylcyclopentasiloxane is 73.4 d at pH 7 and 25°C. The water solubility of the substance is low (17 µg/l at 23°C) and the log Kow is high (8.07). It is therefore likely that, under the flow-through exposure conditions of the aquatic toxicity tests reported in the following sections, that the test organisms will have been predominantly exposed to very low concentrations of the registered parent substance.
Conclusion on classification
It is proposed that D5 should not be classified in the EU for environmental hazards. The substance was found to be non-toxic at its functional water solubility limit in short- and long-term studies with fish, Daphnia and algae.
To add further certainty “to assess likelihood or severity of an event occurring due to physicochemical properties of the substance” as defined in the REACH requirements, a new risk analysis method that applies thermodynamic principles of ‘fugacity’ and ‘activity’ to express the results of field monitoring and laboratory bioaccumulation and toxicity studies in a comprehensive risk analysis was conducted on D5 (Gobas et al., 2015). Fugacity (f) or activity (a) is the chemical potential of a substance in a given media or phase.
The use of fugacity/activity to describe the degree of saturation (or solubility) achieved by a compound in a given media is particularly useful for substances that display a narcosis mode-of-action in aquatic organisms, e.g., the cVMS substances (Redman et al., 2012), as chemical activities may provide valuable estimates of the proximity of measured concentrations to potentially toxic levels (Arnot and Mackay, 2011). Gobas et al. (2015) examined the available field data on D5 and concluded that:
“Fugacity and activity ratios of D5 derived from bioaccumulation measures indicate that D5 does not biomagnify in food-webs, likely due to biotransformation. The fugacity and activity analysis further demonstrates that reported no-observed effect concentrations of D5 normally cannot occur in the environment. Observed fugacities and activities in the environment are, without exception, far below those corresponding with no observed effects, in many cases by several orders of magnitude. This analysis supports the conclusion of the Canadian Board of Review and the Minister of the Environment that D5 does not pose a danger to the environment.”
D5 does not reach concentrations in surface water or sediment that cause toxicity to pelagic or benthic organisms. Analysis of chemical activity and fugacity shows that concentrations of D5 measured in biota, including plankton, invertebrates, fish, birds, and terrestrial and marine mammals are three to nine orders of magnitude below the maximum activity of one and below all NOEC levels.
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.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
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