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EC number: 217-496-1 | CAS number: 1873-88-7
- 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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Toxicity to soil macroorganisms except arthropods
Administrative data
Link to relevant study record(s)
- Endpoint:
- toxicity to soil macroorganisms except arthropods: long-term
- Data waiving:
- study technically not feasible
- Justification for data waiving:
- other:
Reference
Description of key information
Key value for chemical safety assessment
Additional information
There are no reliable data describing the long-term toxicity of the registered substance to soil macroorganisms.
Stability study using the related substance octamethyltrisiloxane (L3) under OECD TG 222 conditions without test organisms:
A stability/recovery test was conducted in preparation for terrestrial ecotoxicology studies with the related substance L3. H-L3 and L3 are members of the Siloxane Category of compounds and have high vapour pressures (850 Pa and 530 Pa), high log Kow (6.2 and 6.60), high log Koc (3.8 and 4.3) and low water solubility (0.02 mg/l and 0.034 mg/l). In addition, the substances have a slow hydrolysis rate relative to the time-scale of ecotoxicity testing (t1/2 = 53 h and 329 hours at pH 7 and 25°C). In the context of terrestrial toxicity, both L3 and H-L3 are expected to have similar stability in soil and prior to volatilisation, any exposure is likely to be to the parent substance during the terrestrial toxicity studies. Therefore, it is considered valid to read-across the results of the soil stability study with L3.
The study demonstrated a method of introducing neat 14C-octamethyltrisiloxane (14C-L3) into natural soil with subsequent mixing to distribute the test article throughout the soil uniformly.
The second phase of the study investigated the stability of 14C-L3 in the same soil under conditions representative of those used for the OECD TG 222 Earthworm Acute Toxicity and Reproduction Test. The system was partially open to allow for respiration during a planned future toxicity experiment.
Effect of headspace on loss of test material during dosing of soil was examined. The main experiment test vessel was selected in order to minimise headspace as much as possible, while still allowing for enough tumbling to ensure homogeneity. However, even the container with the best recovery only observed an average recovery of 69.7% (or 22.9 mg/kg soil (d.w.)).
Measures were taken to avoid loss of test substance through volatilisation during the homogeneity experiment. These included:
- fitting the test vessel jar with a polytetrafluoroethylene (PTFE) lined lid and covering the threads of the jar with PTFE tape;
- spiking the soil with a calibrated gastight syringe;
- spiking with a concentration 34% above the saturation concentration, to attempt to account for test substance losses;
- taping the lid closed to avoid inadvertent opening.
The stability experiment was then carried out using the spiked soil from the homogeneity experiment, which was divided into five beakers. Each beaker had 10 mL of headspace and was covered with plastic film having five small holes (approximately 3 mm in diameter) to allow for air exchange. The plastic film was secured with rubber bands.
By day 3 in the stability experiment, only 6.3% of the initially observed radioactivity was detected, and sampling was stopped. However, the average of the homogeneity determination was taken as the initial concentration for each beaker in the stability test. The soil was not analysed again after dividing into the beakers, therefore the potential loss from moving the test soil from the container used in the homogeneity experiment to the 5 test beakers used in the stability study was not determined.
A single peak was observed consistent with14C-L3, showing that the primary mechanism of loss in the initial recovery experiment was volatilisation.
The absence of degradation products in the vast majority of samples, coupled with the rapid loss of 14C activity, shows that the primary mechanism of test article loss was volatilisation of 14C-L3 from the simulated OECD TG 222 test setup.
H-L3 is more volatile and also more rapidly degradable than L3, meaning that similar losses from the test system would be expected under equivalent test conditions. Additionally, in an OECD TG 216 (Soil Microorganisms: Nitrogen Transformation Test) study for the effects of the related substances HMDS and L3 on nitrate formation rate of soil microflora, analysis of the test substance concentrations show that test material was lost by day three of the test (see Section 6.3.4). Based on these experimental findings, the registrants believe it is not technically feasible to conduct an OECD TG 222 test for the registration substance on the basis that the test substance is too volatile to maintain adequate concentrations in the test system.
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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