Zirconium, niobium, antimony and fluorine in mice: effects on growth, survival and tissue levels.

To evaluate innate effects of certain trace elements, 540 mice were fed a diet of rye, corn oil and dried skim milk containing moderate amounts of zirconium and niobium and no detectable antimony or fluorine, in an environment relatively free of trace contaminants. Groups of 108, divided as to sex, were given 5 ppm zirconium, niobate or antimony or 10 ppm fluoride in drinking water from weaning until natural death. Females given fluoride grew somewhat larger at older ages and both sexes survived as long as their controls. Inherent toxicity, manifest by decreased median life spans and longevity and by some suppression of growth of older animals, was observed in females given niobium and antimony. The . feeding of niobium was ass.ociated with an increased incidence of hepatic fatty degeneration. No element was carcinogenic or tumorigenic. Fluoride did not accumulate in soft tissues, but increments of niobium and antimony were found. Zirconium occurred in both controls and experimental groups, and showed sll&ht toxicity. Of 15 trace elements studied in this manner, chromium, fluorine and nickel showed no demonstrable innate toxicity, whereas tellurium, arsenic, tin and vanadium showed the most. Innate biological effects of small doses of trace elements, given to mice and rats in drinking water from the time of weaning until death are being studied in an environment relatively free of contaminating trace elements. Effects of 9 elements given to mice have been reported: titanium, vanadium, chromium, nickel, germanium, arsenic, cadmium, tin, and lead ( 1, 2). The present study concerns zirconium, niobium, antimony and fluorine, all of which are present in food and in human tissues.