Man-made vitreous (silicate) fibres with random orientation with alkaline and alkali earth oxides (Na2O+K2O+CaO+ MgO+BaO) content greater than 18% by weight and fulfilling one of the CLP Regulation Annex VI Note Q conditions

Endpoint summary

Description of key information

Short description of key information on bioaccumulation potential result:

It is assessed that MMVF note Q fibres are not taken up into the body by inhalation, ingestion or dermal contact. Inhaled fibres are cleared from the lungs and swallowed, and are rapidly disintegrated in the lung and the gastrointestinal fluids. No systemic exposure is expected.

Key value for chemical safety assessment

Bioaccumulation potential:

no bioaccumulation potential

Additional information

Comparable to guideline studies are used for the assessment along with the acceptable, well-documented publications which meet basic scientific principles.

The most likely exposure routes for MMVF note Q fibres are evaluated to be by inhalation and skin contact. In the case of workers, fibres may be swallowed after clearance from the respiratory tract; whereas ingestion is considered very unlikely. Inhalation toxicity studies found no exposure related systemic lesions related, indicating that the fibres do not translocate in the body, i.e. are not taken up through the lungs. No information has been found on absorption of MMVF note Q fibres through the skin or the gastrointestinal tract. However, MMVF note Q fibres are inorganic fibres with low potential to penetrate biological membranes, thus absorption through the skin and the gastrointestinal tract is assessed to be negligible.

MMVF note Q fibres exposed to a neutral pH lung fluid or an acidic environment in macrophages have been shown to disintegrate rapidly. Thus, MMVF note Q fibres disappear rapidly from the lungs, making systemic exposure to MMVF note Q fibres very unlikely. The half-life time (T_1/2) of MMVF note Q fibres (length > 20 μm) is in the range 5-9 days in short-term biopersistence inhalation study and in the range 15-37 days in intratracheal biopersistence studies depending on the specific fibre type. MMVF note Q fibres are also cleared by lung clearance through the mucociliary escalator and e.g. swallowed.

Discussion on bioaccumulation potential result:

The most likely exposure routes for MMVF note Q fibres are evaluated to be by inhalation and skin contact. In addition, in the case of workers fibres may be swallowed after clearance from the respiratory tract; but ingestion is considered less likely. Inhalation toxicity studies found no exposure related systemic lesions related, indicating that the fibres do not translocate in the body, i.e. are not taken up through the lungs. No information has been found on absorption of MMVF note Q fibres through the skin or the gastrointestinal tract. However, MMVF note Q fibres are inorganic fibres with low potential to penetrate biological membranes, thus absorption through the skin and the gastrointestinal tract is assessed to be negligible.

MMVF note Q fibres, which are exposed to an acidic environment, have been shown to disintegrate rapidly. Thus, systemic exposure to MMVF note Q fibres leading to toxic reactions is evaluated to be very unlikely.