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EC number: 231-135-5 | CAS number: 7440-25-7
- 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

Endpoint summary
Administrative data
Description of key information
Data describing the aquatic toxicity of Ta metal are not available. Due to the high water insolubility of the substance (0.043 µg/L according to OECD 29 (loading 1 mg/L after 28 days), toxicity to aquatic organisms is not expected.
This expectation is substantiated by data available for the read-across source TaCl5 (for justification please refer to IUCLID section 13).
Additional information
Data describing the acute aquatic toxicity of TaCl5 to aquatic organisms are available for fish, invertebrates, algae and microorganisms.
In a study conducted according to OECD guideline 203, zebra fish (Danio rerio) were exposed to TaCl5 at nominal concentrations of 0 and 100 mg/L under semi-static conditions (limit test). No mortality could be observed. Due to methodological constraints, effect levels are provided as nominal loading rates. Hence the 96-h LL50(nominal) is > 100 mg/L.
An activated sludge respiration inhibition test with TaCl5 according to OECD 209 resulted in an EL50> 1000 mg/L and an NOEL ≥ 1000 mg/L.
In a study in accordance with OECD guideline 202 the 48-h acute toxicity of TaCl5 to Daphnia magna was studied under semi-static conditions at nominal concentrations of up to 3000 mg/L. The 48-hour EL50 was 3086 mg/L. The 48-h NOELR based on immobilization was 2000 mg/L and the LOELR was 3000 mg/L.
The toxicity of TaCl5 to cultures of Pseudokirchneriella subcapitata after 72 h (growth inhibition test) was investigated in accordance with OECD guideline 201 at nominal concentrations of up to 2000 mg/L. Results based on growth rate after 72 h were as follows:
- EL50: > 2000 mg/L;
- LOELR: 500 mg/L;
- NOELR: 250 mg/L.
Please note that in aquatic toxicity tests conducted with TaCl5 it was not possible to determine effect levels based on measured effective test substance concentrations. Addition of TaCl5 to water leads to strong temperature rise and a strong shift in pH value (< 1). Thus, pH values had to be adjusted in all tests by the addition of NaOH. After pH adjustment, the measured Ta5+ concentrations were low and showed high variability. Therefore, no concentration-response relationship could be established. Concentrations of the test item varied due to precipitation, agglomeration and adsorption reactions. In addition, slight changes in pH had significant impact on the test item concentrations. Observed effects in daphnia and algae at very high test substance concentrations may therefore rather predominantly refer to elevated sodium chloride (NaCl) concentrations, originated from neutralization, than released Ta5+ ions. Reported EC50 values in daphnia and inhibitory concentrations in algae for NaCl vary but may be as low as EC50= 874 mg/L (ECHA registry for sodium chloride) and IC50= 0.87-2.5 g/L (IC = inhibition of fluorescence; Santos et al., 2007, in Heisterkamp, 2015; Geis et al., 2000), respectively. Due to NaCl concentrations of approximately 2.92 g/L present at the highest loading rate of 2000 mg/L test substance in the OECD 201 test, and 2.34 g/L present at the highest loading rate of 3000 mg/L in the OECD 202 test, and the sensitivity of P. subcapitata and D.magna to salinity, any hypothetical Ta5+ related effects cannot be distinguished from NaCl induced growth inhibition/immobility in these tests. Therefore, effects can be rather attributed to NaCl than to the release of Ta5+ ions.
This information is used in a read-across approach in the assessment of the substance to be registered.
For details and justification of read-across please refer to the attached report in section 13 of IUCLID.
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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