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Toxicological information

Endpoint summary

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Key value for chemical safety assessment

Toxicity to reproduction: other studies

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.

More detailed information on read-across can be found in IUCLID 0 "category".

 

Zinc:

Dietary supplementation with zinc at 20 mg/day did not result in adverse effects of pregnancy progress or outcome in healthy pregnant women in a number of large, controlled trials (Huntet al, 1984; Kynast and Saling, 1986; Mahomedet al, 1989). Similarly, supplementation with zinc at 30 mg/day did not result in any adverse outcomes in a double blind trial involving low income pregnant adolescents (n=268 at delivery) thought to have low zinc status (Cherryet al, 1989). In a smaller study, Jameson (1976) gave zinc supplements of 90 mg/day to seven pregnant women with low serum zinc concentrations and found no adverse effects. Moreover, in a follow-up study by the same author (Jameson, 1982), 133 women with low serum zinc concentrations were randomly assigned to either zinc supplementation at 45 mg/day or no supplementation and no adverse effects were reported. These data indicate that zinc supplementation at doses of 20-90 mg/day produce no adverse effects on pregnancy outcome (EFSA, 2006).

Fluoride:

Collins, et al. (2001) reported that sodium fluoride in drinking water of Sprague-Dawley rats at levels up to 250 ppm the highest concentration tested. This cocentration, equivalent to 28.4 mg sodium fluoride/kg body weight/day or 12.8 mg fluoride/kg body weight/day, had no adverse effects on reproduction throughout three generations. Mating, fertility and survival indices were not affected.

Justification for classification or non-classification

Based on the overall evaluation of the available data for soluble inorganic zinc substances and fluorides (i.e., potassium and sodium) on reproduction and developmental toxicity, a classification and labelling for reproduction of zinc difluoride is not considered to be justified according to Regulation (EC) 1272/2008.