Diniobium pentaoxide

PBT assessment

PBT assessment: overall result

PBT status:

the substance is not PBT / vPvB

Justification:

8.1.1. Summary and overall conclusions on PBT or vPvB properties

Taking into account all available data on biotic and abiotic degradation, bioaccumulation and toxicity it can be stated that diniobium pentaoxide is neither toxic nor does it accumulate in living being, but it is judged to be very persistent in the environment. Since not all three criteria for persistence, bioaccumulation and toxicity are fulfilled,diniobium pentaoxideis judged not to be a PBT substance.

8.1.2. PBT/vPvB criteria and justification

Persistence Assessment

According to the “Guidance on information requirements and chemical safety assessment Chapter R.11: PBT Assessment” (ECHA, 2008) the screening assessment for persistence should be based on all available data from biodegradation studies, abiotic degradation studies and estimation models.

Sincediniobium pentaoxideis an inorganic substance biodegradation cannot be assessed. Abiotic degradation is also not expected to occur. The substance is stable in water and does not hydrolyze. It is not volatile and does not enter into the atmosphere hence a reaction with atmospheric molecules, like OH radicals and a consequently degradation is impossible.Diniobium pentaoxidemetal is considered to remain stable in nature and thus to be persistent (P).

Bioaccumulation Assessment

Diniobium pentaoxideis insoluble in water (< 0.5 μg/L) and not bioavailable to aquatic species. As an inorganic substance without any bioavailability, Nb2O5 cannot be metabolized. Under physiological conditions,diniobium pentaoxidecannot be absorbed via skin or gastrointestinal tract. Even in case of absorption via the oral route and ingested, Nb will be eliminated via faeces without prior absorption. Thus, there is no potential for bioaccumulation anddiniobium pentaoxideis considered neither to be bioaccumulative (B) nor very bioaccumulative (vB).

Toxicity Assessment

According to the “Guidance on information requirements and chemical safety assessment Chapter R.11: PBT Assessment” (ECHA, 2008) the PBT assessment for toxicity must be based on NOEC values for marine or freshwater organisms, and on considerations of the classification of the substance as CMR and/or chronic toxic to humans.

No data is available on aquatic organisms, carcinogenicity and toxicity to reproduction. Sincediniobium pentaoxideis insoluble in water and not bioavailable via any route it is not considered to cause any adverse effect neither to animals nor to humans. An acute dermal study withdiniobium pentaoxideshowed no effect,diniobium pentaoxideis neither irritant to skin nor to the eye and was found to be not sensitizing. Three studies on genetic toxicity showed thatdiniobium pentaoxideis not mutagenic. Based on these datadiniobium pentaoxide is considered not to be toxic (T).