ZINC TOXICITY IN MAN AND EXPERIMENTAL SPECIES

Many of the metals or metal salts exert a degree of toxicity when ingested, inhaled or placed on the skin surfaces. The level of a metal which causes a toxic reaction varies tremendously with the mineral. Zinc salts are not particularly toxic in comparison with salts of copper, molybdenum, mercury, etc. In man, the inhalation of air containing from 3 to 15 mg zinc/cm during working hours over a period of many years apparently exerts no toxic manefestations. Skin sensitivity to zinc appears to be relatively rare, although salts such as zinc chloride have a caustic action and can cause damage to the skin. The action in this case cannot be attributed to the zinc ion. Many cases of poisoning due to the ingestion of zinc salts have been reported. These cases usually occur through the use of galvanized containers to store acid foods or drinks. The emetic dose of zinc sulfate has been reported to be 1 to 2 gm which would be equivalent to 225 to 450 mg of zinc. Zinc toxicity in rats has been shown to result in growth depression and anemia. Some evidence is presented to indicate that the anemia produced in this manner can be overcome by simultaneous copper administration. Zinc toxicity in other species of experimental animals is discussed. Pub in Zinc Metabolism p1-15 1966.