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Diss Factsheets
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EC number: 237-623-4 | CAS number: 13870-28-5
- 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:
- 7.5 mg/L
Marine water
- Hazard assessment conclusion:
- PNEC aqua (marine water)
- PNEC value:
- 7.5 mg/L
STP
- Hazard assessment conclusion:
- PNEC STP
- PNEC value:
- 28 mg/L
- Assessment factor:
- 10
- Extrapolation method:
- assessment factor
Sediment (freshwater)
- Hazard assessment conclusion:
- PNEC sediment (freshwater)
- PNEC value:
- 29.4 mg/kg sediment dw
- Extrapolation method:
- equilibrium partitioning method
Sediment (marine water)
- Hazard assessment conclusion:
- PNEC sediment (marine water)
- PNEC value:
- 29.4 mg/kg sediment dw
- Extrapolation method:
- equilibrium partitioning method
Hazard for air
Air
- Hazard assessment conclusion:
- no hazard identified
Hazard for terrestrial organisms
Soil
- Hazard assessment conclusion:
- PNEC soil
- PNEC value:
- 1.47 mg/kg soil dw
- Extrapolation method:
- equilibrium partitioning method
Hazard for predators
Secondary poisoning
- Hazard assessment conclusion:
- PNEC oral
- PNEC value:
- 106 mg/kg food
- Assessment factor:
- 30
Additional information
The crystalline structure of layered delta-sodium disilicate is completely destroyed by dissolution in water yielding an aqueous solution which is identical to a solution of amorphous sodium disilicate (CAS No. 1344-09-8) and so called water glas is formed. In consequence, the argumentation form the soluble silicates HERA risk assessment Report (2005) is adopted. The primary hazard of commercial soluble silicates is their moderate-to-strong alkalinity, which can be harmful to aquatic life. However, most of natural aquatic ecosystems are slightly acid or alkaline and usually their pH values fall within the range of 6 – 9, and due to the high buffer capacity of these ecosystems pH effects of released soluble silicates to aquatic organisms are very unlikely. Consequently, the PNEC derived from artificial laboratory test systems overestimate the effects of soluble silicates to aquatic organisms in ecosystems. Therefore, the PNEC was derived from the ubiquitous SiO2 background concentration in the environment. The median values in the US were reported to be 17 mg SiO2/L for ground waters and 14 mg SiO2/L for streams (Davis 1964). The world-wide mean concentration in rivers is 13 mg SiO2/L (Edwards and Liss 1973) and in Europe is 7.5 mg SiO2/L (Jorgensen et al. 1991). Therefore, the conservative PNEC for aquatic organisms is 7.5 mg SiO2/L and was used for the final risk characterisation.
References:
Davis SN (1964). Silica in streams and ground water. Am. J. Sci. 262, 870-891.
Edwards AMC and Liss PS (1973). Evidence of buffering of dissolved silicon in fresh waters. Nature 243, 341-342.
Hera Risk Assessment Report Soluble Silicates, February 2005
Jorgensen SE, Nielsen SN, Jorgensen LA (1991): A Handbook of ecological parameters and ecotoxigology, Elsevier : Amsterdam, The Netherlands.
Conclusion on classification
Acute toxicity:
Algae (Scenedesmus subspicatus) is the most sensitive species with a EC50 value of 44.1 mg/L (pH adjustment to pH 7.6 at the start of the test, but no pH adjustments during the test). All other EC50 values for fish and Daphnia were far above the trigger value of 100 mg/L. According to 67/548/EEC and CLP (GHS) disodium disilicate (delta-crystalline) has not to be classified regarding acute toxicity to the environment as the lowest LD50 value is above 1 mg/L.
Chronic toxicity:
No test on biodegradability of the test substance is available as the substance is of inorganic nature. In a hydrolysis study, it was concluded that the crystalline structure of disodium disilicate (delta-crystalline) is completely destroyed by dissolution in water yielding an aqueous solution which is identical to a solution of amorphous sodium disilicate (CAS No. 1344-09-8). In addition log Koc and BCF values are expected to be very low as the substance is not soluble in octanol.
With regard to classification disodium disilicate (delta-crystalline) is thus regarded as degradable in nature and has in conclusion not to be classified regarding chronic toxicity to the environment according to 67/5487EEC and CLP (GHS).
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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