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Toxicological information

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Description of key information

Reliable substance-specific information concerning the toxicity for zinc difluoride does not exist. Instead, toxicological information on very soluble inorganic fluoride (mainly sodium fluoride) substances and very soluble inorganic zinc substances were extrapolated to zinc difluoride considering that systemic effects mainly based on the concentrations of the Zn2+ and F- ions, which are the key concern of zinc difluoride.

Please refer to the report attached on IUCLID section 13 "ZnF2_Read Across Assessment Framework Report"

Key value for chemical safety assessment

Bioaccumulation potential:
no bioaccumulation potential

Additional information

Selected endpoints for the human health hazard assessment are addressed by read-across, using a combination of data on the fluoride moiety and the zinc moiety (or one of its readily soluble salts). This way forward is acceptable, since zinc difluoride dissociates to the fluoride anion and the zinc cation upon dissolution in aqueous media.

Once the individual constituents of zinc difluoride become bioavailable (i.e., in the acidic environment in the gastric passage or after phagocytosis by pulmonary macrophages), the “overall” toxicity of the dissociated substance can be described by the toxicity of the “individual” constituents. Since synergistic effects are not expected, the human health hazard assessment consists of an individual assessment of the zinc cation and the fluoride anion.

Zinc difluoride readily dissociates to the corresponding zinc cations and fluoride anions. The zinc cation and the fluoride anion are considered to represent the overall toxicity of zinc difluoride in a manner proportionate to the fluoride and the metal (represented by one of its readily soluble salts). Based on the above information, unrestricted read-across is considered feasible and justified.