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EC number: 200-848-3 | CAS number: 75-20-7
- 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

Ecotoxicological Summary
Administrative data
Hazard for aquatic organisms
Freshwater
- Hazard assessment conclusion:
- PNEC aqua (freshwater)
- PNEC value:
- 4.62 µg/L
- Assessment factor:
- 1 000
- Extrapolation method:
- assessment factor
- PNEC freshwater (intermittent releases):
- 46.2 µg/L
Marine water
- Hazard assessment conclusion:
- PNEC aqua (marine water)
- PNEC value:
- 0.462 µg/L
- Assessment factor:
- 10 000
- Extrapolation method:
- assessment factor
STP
- Hazard assessment conclusion:
- no emission to STP expected
Sediment (freshwater)
- Hazard assessment conclusion:
- no exposure of sediment expected
Sediment (marine water)
- Hazard assessment conclusion:
- no exposure of sediment expected
Hazard for air
Air
- Hazard assessment conclusion:
- no hazard identified
Hazard for terrestrial organisms
Soil
- Hazard assessment conclusion:
- no exposure of soil expected
Hazard for predators
Secondary poisoning
- Hazard assessment conclusion:
- no potential for bioaccumulation
Additional information
The PNECs of calcium carbide for the aquatic environment are based on acute aquatic toxicity tests conducted with calcium carbide of technical grade. Assessment factors in agreement with pertinent guidance documents by ECHA were applied. PNECs for sediment and terrestrial compartments were not derived for the following reasons: Calcium carbide decomposes rapidly in contact with moisture, forming acetylene and calcium hydroxide. Calcium hydroxide is alkaline, and therefore has the capacity to change the pH of environmental media. Aquatic ecosystems are characterised by pH, among other factors; the organisms inhabiting any ecosystem are adapted to the prevailing 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 against 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 No. 7647-01-0). The buffering capacity of the environment will neutralise calcium hydroxide formed from calcium carbide. Ca2+ (from Ca(OH)2) is a ubiquitous substance with no toxicological relevance in the concentrations released from CaC2. Moreover, Ca2+ is an essential mineral nutrient for humans and animals that is homoeostatically regulated in the body. Acetylene has a high tendency to volatilise and will not remain in the aqueous phase. Furthermore, acetylene has a very low potential to adsorb to soil or sediment due to its low partitioning coefficient (log Pow = 0.37). Thus, exposure of sediments to acetylene based on the release of CaC2 to surface water is not expected.
Due to the identified uses of CaC2 direct release of the substance to soil and/or surface waters can be excluded. Indirect exposure (deposition via air) is negligible as CaC2 is released in the form of fine particles with very high surface area, that are transformed into Ca(OH)2 and C2H2. C2H2 is a gas and will remain in the gaseous phase. Due to the very high particle surface Ca(OH)2 is highly reactive and will undergo quick transformation to CaCO3 upon contact with CO2 (within hours to few days). Thus, only CaCO3 will be deposited in soil. CaCO3 is of no toxicological or environmental concern as the substance is a constituent of the soil matrix anyway.
Furthermore, neither calcium carbide nor its degradation products calcium hydroxide and acetylene have a tendency to accumulate in the food chain (for details please refer to the endpoint bioaccumulation in IUCLID section 5.3). Therefore, a risk for secondary poisoning in the food chain by calcium carbide can be excluded.
Conclusion on classification
Calcium carbide instantly decomposes hydrolytically upon contact with water/moisture, yielding calcium hydroxide and acetylene. Studies on the acute toxicity to aquatic invertebrates, algae and fish are available that were conducted with technical calcium carbide. Therefore, effects reported in these studies can be attributed to the entirety of the decomposition products of technical calcium carbide, i.e. calcium hydroxide and acetylene, including any impurities of the technical material. The lowest acute effect concentration of technical calcium carbide among the three aquatic species could be observed in Daphnia magna. The reported effect level (EC50) after 48-hr exposure is 4.62 mg CaC2/L. As long-term toxicity studies with technical calcium carbide are not available the classification of the substance is based on the available acute aquatic toxicity data. As the lowest acute effect level is 4.62 mg/L in Daphnia magna, classification for Category Acute 1 is not warranted. Furthermore, classification for Category Chronic 2 is not warranted either as this category does only apply to substances with effect levels in the range 1 to 10 mg/L that are moreover not rapidly biodegradable and/or that have a BCF value ≥ 500 (or a log Pow ≥ 4). The biodegradability criterion neither applies to calcium carbide nor to its decomposition product calcium hydroxide since they are inorganic substances. The second degradation product acetylene is considered to be readily biodegradable. Regarding the bioaccumulation potential, calcium is an essential mineral nutrient for animals and humans that is homoeostatically regulated in the body. Calcium hence is devoid of any bioaccumulation potential. Acetylene has a very low log Kow (0.37) and is thus not expected to have a significant bioaccumulation potential.
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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