Registration Dossier

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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information



Summary of degradation

Ditantalum pentaoxide is inorganic and hence the ready biodegradation test as well as simulation tests on biodegradation in water, sediment and soil are not relevant. Due to the high insolubility of the substance (max. solubility 0.16 µg/L, loading 100 mg/L, after 7 days in OECD 29), hydrolysis of the substance is as well not relevant. Abiotic and biotic degradation will not occur.



Data on volatilisation are not available for the substance. Ditantalum pentaoxide is a solid with a melting point > 300 °C. Thus, the vapour pressure of the substance is negligible and it is hence not considered volatile.


Distribution modelling

No distribution modelling data exist. Modelling is not applicable to an inorganic substance such as ditantalum pentaoxide.


Summary of environmental distribution

The HPLC screening study to address adsorption/desorption behaviour is not applicable to metal compounds. A full adsorption/desorption study in accordance with OECD Guideline 106 does not need to be conducted as the study is technically not feasible for a substance with such a low water solubility.


Summary and discussion of bioaccumulation

No reliable experimental data on bioaccumulation in aquatic species exist. Based on the high insolubility in water and the high molecular weight, the substance is not considered to be bioavailable.

Secondary poisoning

Bioaccumulation of ditantalum pentaoxide is not expected to occur. Hence no secondary poisoning risk exists.


Assessment of PBT/vPvB Properties - Comparison with the Criteria of Annex XIII

According to the Guidance on information requirements and chemical safety assessment, Chapter R.11: PBT assessment, “the PBT and vPVB criteria of Annex XIII to the regulation do not apply to inorganic substances”. Therefore the substance is not considered to require any further assessment of PBT properties.